Department of Electrical & Computer Engineering

Annual ResearchAnnual Research ReportReport

Department of Electrical and Computer EngineeringPolytechnic Institute of NYU

Five Metrotech CenterBrooklyn, NY 11201

Phone: (718) 260 3590Fax: (718) 260 3906

LAST UPDATED 5/6/2023

http://eeweb.poly.edu

The Department of Electrical and Computer Engineering is home to two research centers:

CATTCATTThe Center for Advanced Technology in Telecommunications and Distributed Information Systems (CATT) is a research and education group at Polytechnic Institute of NYU, long-recognized as one of the best engineering schools in the country.

Our researchers are leaders in the fields of electrical engineering and computer science. The Center also draws on the expertise of key researchers at Columbia University.

Companies that partner with CATT in joint research gain access to state-of-the-art facilities and a team of experts who understand how to turn technological breakthroughs into commercially viable products and services.

The Center Director is Prof. Shivendra Panwar.

For more information, please refer to http://catt.poly.edu/index.html.

WICAT WICAT The Wireless Internet Center of Advanced Technology (WICAT) is a joint research center created by Columbia University and Polytechnic Institute of NYU. As a future Industry/University Cooperative Research Center member, WICAT is partnered with companies and organizations from across the industry, from telecommunications and manufacturing giants to wireless customers and small start-up firms.

The I/UCRC program helps industry and academia come together to overcome practical research challenges. For WICAT, this means that companies who become our partners help to direct future areas of wireless study and gain first access to new research. This research is aimed at anticipating not only their needs, but also the needs of their clients, suppliers and the industry as a whole.

WICAT’s goal is to be a catalyst for wireless innovation, and to help foster an ecosystem that partners vendors, service providers, government agencies, research initiatives, end-users, and small companies and start-ups. Our mission is both to facilitate communication between these partners and to provide them with a pool of research that can be applied to practical problems in the wireless industry.

The Center Directors are Profs. Henry Bertoni (Poly) and Andrew Campbell (Columbia). For more information, please refer to http://www.poly.edu/wicat/.

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This report is a collection of ongoing research projects undertaken by ECE faculty in the areas of

I.I. Fields and WavesFields and Waves

II.II. Systems, Control and Signal ProcessingSystems, Control and Signal Processing

III.III. Telecommunications and WirelessTelecommunications and Wireless

IV.IV. VLSI, Electronics and PowerVLSI, Electronics and Power

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List of Contributors

Henry Bertoni hbertoni@duke.poly.edu

Frank Cassara cassara@rama.poly.edu

Jonathan Chao chao@poly.edu

Dariusz Czarkowski dcz@pl.poly.edu

Nirod Das ndas@photon.poly.edu

Elza Erkip elza@poly.edu

David J. Goodman goodman@duke.poly.edu

Zhong-Ping Jiang zjiang@control.poly.edu

Ramesh Karri ramesh@india.poly.edu

Farshad Khorrami khorrami@smart.poly.edu

Spencer Kuo spkuo@rama.poly.edu

Francisco de Leon fdeleon@poly.edu

Yong Liu yongliu@poly.edu

I-Tai Lu itailu@rama.poly.edu

Shivendra S. Panwar panwar@catt.poly.edu

S. Unnikrishna Pillai pillai@hora.poly.edu

Garrett S. Rose grose@duke.poly.edu

Ivan W. Selesnick selesi@taco.poly.edu

Peter Voltz voltz@rama.poly.edu

Yao Wang yao@vision.poly.edu

Zivan Zabar zzabar@poly.edu

Table of Contents

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I. Fields and Waves...........................................................................................................7

II. Systems, Control and Signal Processing......................................................................12

Cooperative Control of Multi-Agent Systems....................................................................13

Robust Adaptive Nonlinear Control System Designs........................................................16

Development of Hardware/Software Architecture for Autonomous Unmanned Vehicles....18

Nonlinear Control for Electric Motors................................................................................20

Development of an Ultra-Accurate High-Speed Six DOF Manipulator and Other Robotic Systems..........................................................................................................................22

Decentralized Control of Nonlinear Large-Scale Interconnected Systems.........................24

III.Telecommunications and Wireless...............................................................................25

Cooperative Source and Channel Coding........................................................................26

Cooperative Regions and Partner Choice in Coded Cooperative Systems........................28

Power Efficient Multimedia Wireless Communications......................................................29

Peer-to-Peer Video Streaming System............................................................................31

Sensor Management.......................................................................................................34

Unlocking Capacity for Wireless Access Networks through Robust Cooperative Cross-Layer Design...................................................................................................................35

Designing Medium Access Control for Cooperative Networks...........................................39

IV. VLSI, Electronics and Power......................................................................................42

Power Electronics for Wireless Devices...........................................................................43

Mitigation of Voltage Disturbances Caused by Nonlinear Electrical Massive Loads...........47

Development of a Unit Substation Demand Estimator......................................................48

Mitigation Techniques to Reduce Inrush Currents of Network Transformers......................49

Architecture.....................................................................................................................50

Hybrid CMOS/Nano Circuit Design..................................................................................55

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I. Fields and Waves

6

7

Wave-Plasma Interactions in Artificial Modification of the Ionosphere and Magnetosphere by Powerful Radio WavesBackground—A major facility for conducting experiments related to basic radio science research as well as DoD missions is under development in Gakona, Alaska, as part of the High Frequency Active Auroral Research Program (HAARP). The present HAARP HF transmitting system is being expanded from a phased-array antenna of 48 elements to one with 180 elements. After completion of this upgrading, its maximum effective radiated power (ERP) will exceed 1 GW. A backscatter radar (450 MHz) will also be installed soon near the heating site to improve the remote sensing capability of the HAARP. A key objective of the program is to explore physical processes that can be initiated in the ionosphere and magnetosphere via interactions with high power radio waves. Shown in Fig. 1 is a photo of the HAARP HF transmitting system before being upgraded.

Two DoD missions of the HAARP program are 1. an ionospheric virtual antenna for underwater communications and 2. an in-situ array of ELF/VLF transmitters for the population control of radiation belt electrons.

Motivation— Signals in communications with submerged submarines have to penetrate deeply into seawater, which is a conducting dielectric; the relative dielectric constant r 72 and the conductivity 4 S/m. Thus the attenuation constant for the high frequency wave is rather high. Fortunately, the attenuation constant decreases with the wave frequency. It has the dependence = 410f Np/m for f 1 GHz. Hence, the wave penetration problem can be resolved by adopting very low frequency carrier. For example, choosing f = 100 Hz leads to = 4102 Np/m and the penetration depth = 25 m. However, the wavelength of 100Hz wave is 3000 km. To implement a high power and large size antenna (megawatts and hundreds of kilometers) on the ground is costly and has to face environmental impact problems.In the magnetosphere, very energetic electrons (in MeV level) in the radiation belts have strong impact on space systems, which are designed to survive certain amount of radiation (ionizing) dose accumulated during the lifetimes. Any unexpected radiation flux enhancement can cause satellites to accumulate radiation damage much faster than designed for, which leads to faster degradation of on-board active electronics. Objective—to advance the understanding of wave-plasma interaction processes that help for the realization of the future Naval/DoD systems for the missions.

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Progress—In the polar region, an electrojet current appears frequently in the lower ionosphere. A dc space charge field drives this current. Thus an amplitude-modulated powerful HF wave modulated at ELF/VLF frequency can be introduced to modulate the electron temperature, which results to the modulation of the electron conductivity in a similar fashion. Consequently, the electrojet current driven by the background dc fields becomes oscillating in time to act virtually as an antenna. The ac part of the current becomes the source current of ELF/VLF radiation. A cartoon showing the antenna and its radiation is presented in Fig. 2. Our research effort is to continuously improve the antenna efficiency and the signal quality,1-3 which are critical to practical applications.Our recent work4 showed that whistler waves could introduce chaotic scattering on energetic electrons; thus it can be an effective approach for controlling the population of energetic electrons in the radiation belts. This process is elaborated in Fig. 3. The threshold conditions are determined by the transition of the surface of section plots from regular to chaotic and by the decrease of the pitch angle to be less than the loss cone angle. This is demonstrated by the sequence of surface of section plots (a-c) and pitch angle scattering plots (d-f) presented in Fig. 4; the wave magnetic field B1 is normalized to the background magnetic field B0, i.e., B1/B0; six trajectories corresponding to 0/ = 3.65-3.9 with 0.05 increment are drawn in the same plot to show the frequency effect and to determine the optimal wave frequency. As shown, the trajectory of 0/ = 3.9 electron becomes the most chaotic at B1/B0

~ 0.006 and its pitch angle is reduced to about 300 at B1/B0

~ 0.015.

Participating Faculty: Spencer Kuo (spkuo@rama.poly.edu)

Collaborators: Drs. James T. Huynh, Paul Kossey, Steven Kuo, and Prof. M. C. Lee

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.........Sponsors: the High Frequency Active Auroral Research Program (HAARP) and the Office of Naval Research (ONR)

1S. P. Kuo, M. C. Lee, P. Kossey, K. Groves, and J. Heckscher, Geophys. Res. Lett., 27, 85, 2000.2S. P. Kuo, S. H. Lee, and P. Kossey, Phys. Plasmas, 9, 315, 2002.3S. P. Kuo and S. H. Lee, Radio Sci., 39, RS1S32 (1-5), 2004.4S. P. Kuo, P. Kossey, J. T. Huynh, and S. S. Kuo, IEEE Trans. Plasma Sci., 32(2), 362-369, 2004.

Selected recent publications:

[J1] M.C. Lee, R. Pradipta, W. J. Burke, A. Labno, L. M. Burton, J. A. Cohen, S. E. Dorfman, A. J. Coster, and S. P. Kuo, “Did Tsunami-Launched Gravity Waves Trigger Ionospheric Turbulence over Arecibo?”, J. Geophys. Res., 113, A01302, doi:10.1029/2007JA012615, 9 January 2008.

[J2] Spencer P. Kuo, Todd Pedersen, and Travis Mills, “Lateral Distribution of Atomic Oxygen Flux Produced by an Array of Three Fan-shaped Plasma Torches”, IEEE Trans. Plasma Sci., 36(3), 1056-1057, doi: 10.1109/TPS.2008.924556, June 2008.[J3] Lance S. Jacobsen, Campbell D. Carter, Thomas A. Jackson, Skip Williams, Jack Barnett, Chung-Jen Tam, Robert A. Baurle, Daniel Bivolaru, and Spencer Kuo, “Plasma-Assisted Ignition in Scramjets”, J. Propulsion and Power, (doi: 10.2514/1.27358) (0748-4658) vol. 24 no. 4, 641-654, Aug. 2008.[J4] Spencer P. Kuo, Yen-Liang Wu, R. Pradipta, J. A. Cohen, and M. C. Lee, “VLF wave generation by amplitude-modulated HF heater waves at Gakona, Alaska”, Geophys. Res. Lett., 35, L13101 (1-5), doi:10.1029/2008GL034414, June 2008.[J5] Spencer P. Kuo, “Plasma Assisted Decontamination of Bacterial Spores”, The Open Biomedical Engineering J., 2, 36-42, doi: 10.2174/1874120700802010036, June 2008.[J6] Spencer P. Kuo, “Mitigation of energetic electrons in the magnetosphere by amplified whistler wave under double cyclotron resonances”, Nonlinear Processes in Geophysics, 15, 773-782, 2008.

Selected recent patents:[P1] Spencer Kuo, “Portable Plasma Sterilizer,” US Patent Application # 12/030982, Date of Filing: Feb. 14, 2008.[P2] Spencer Kuo, “Plasma Assisted Oxygen Decontaminant Generator and Sprayer,” US Patent Application # 12/030962, Date of Filing: Feb. 14, 2008.[P3] Spencer Kuo, “Plasma Torch Implemented Air Purifier,” US Patent Application # 12/126869, Date of Filing: May 24, 2008.

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.........

11

.........

II. Systems, Control and Signal Processing

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.........

Cooperative Control of Multi-Agent Systems

Recently, the rapid advances in communication, computation and miniaturization technologies spur the keen interests of building more and more sophisticated man-made multi-agent systems in numerous industrial and military fields, including multi-vehicle search, rescue and monitoring, traffic control and management, information systems, network security systems, object recognition systems, cooperative decision making mechanism, path planning, task assignment and production scheduling. Compared with conventional single agent systems, multi-agent systems can be made to have more efficiency and robustness and less cost. In the coordination and control of multi-agent systems, decentralized strategies are desirable since the agents often can only get local information from the neighboring agents they can sense and communicate with.

For a multi-agent system to achieve common group objectives or collectively react to unexpected external changes, some information state (e.g. moving direction) of all the agents sometimes need to reach a common value, or consensus. We have contributed some novel solutions leading to relaxation of some existing conditions for the consensus by the well-known averaging consensus protocols. Also our research has derived sufficient conditions for the consensus by a class of non-averaging protocols. In addition, we have presented some novel protocols for the heading consensus of multi-vehicle systems. Our results on the analysis and design of consensus protocols have been integrated into a control strategy that realizes pattern preserving path following of a multiple nonholonomic vehicle team.

Key-words: multi-agent systems, consensus protocol, cooperative control.

Participating Faculty: Z. P. Jiang (zjiang@control.poly.edu)

Research supported by the NSF

[1] Q. Li and Z. P. Jiang, “Relaxed conditions for consensus in multi-agent coordination,” Journal of System Science and Complexity, vol. 21, no. 3, pp. 347-361, 2008.

[2] Q. Li and Z. P. Jiang, “Two decentralized heading consensus algorithms for nonlinear multi-agent systems,” Asian Journal of Control, special issue on “Collective Behavior and Control of Multi-Agent Systems”, vol. 10, no. 2, pp. 187-200, 2008.

[3] Q. Li and Z. P. Jiang, “Global analysis of multi-agent systems based on vicsek's model,” IEEE Trans. on Automatic Control, accepted.

[4] Q. Li and Z. P. Jiang, “Pattern preserving path following of unicycle teams with communication delays,” submitted for publication.

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.........Analysis and Control of Communication NetworksIn the past decade, the analysis and control of communication networks attracts great research interests. As an example, optimization tools have been successfully applied to flow control problems in Internet. The design objective of optimization-based flow control is to maximize the overall network utility function, subject to the constraints of link capacities. In [5], we solve this problem using a modified Aitken Extrapolation algorithm. Furthermore, we perform convergence speed analysis for optimization-based flow control algorithms.

Except for the utility and cost optimization problem, recently, great attention is paid to Internet congestion control since congestion causes packet loss and results in network under-utilization (Figure 1). We notice that, compared with the large body of work on stability analysis for existing congestion control schemes, the synthesis of nonlinear controllers with improved performance has not received enough attention. We focus on designing new AQM schemes to stabilize the nonlinear network model, with particular interest in output feedback design, owing to the advantage of only measuring limited output information--buffer queue length. Previously, the output feedback design for AQM schemes is based on linearized model with known network parameters. With the help of Lyapunov design technique, adaptive feedback linearization and filtering techniques, we design a new, nonlinear controller to achieve both asymptotic stabilization and adaptation to unknown parameters [2]. The output feedback solution represents a nontrivial application of modern nonlinear control theory. We also believe that the design in [2] should provide benefits to future networking technical developments and serve as guidance for distributed protocol designs.

There have been continued interests in applying modern control theory to systematically address new challenges in large-scale networks. Currently, many existing work on controlling communication networks are based upon linear control techniques. Hard nonlinearities, such as saturation caused by capacity constraints, have not been thoroughly addressed, especially when designing control schemes for large-scale networks. In this project, we apply nonlinear control theory to cope with saturation constraints and nonlinear disturbances. In [1], [3] and [4], the constrained regulation of a class of network systems is studied. Explicit conditions are identified under which the problem of asymptotic regulation against unknown traffic interferences is solvable, with control and state saturations. We achieve either asymptotic or practical regulation for a single-node system in [1]. We also propose decentralized, discontinuous control laws to achieve asymptotic regulation of cascaded nodes and large-scale networks in [3], [4]. Our research demonstrates that tools from nonlinear system theory can play an important role in tackling “hard nonlinearities” and “unknown disturbances” for controlling communication networks. The control architecture for a single-node system is shown in Figure 2.

Another line of our research is the analysis and design of wireless ad hoc broadcasting protocols. Ad hoc network is composed of a set of self-organized users that agree to relay packets for each other. Different from conventional cellular wireless systems, ad hoc networks have no fixed infrastructure and central administration. Furthermore, each user can move randomly and the topology changes occur frequently. In such distributed and dynamic networks, broadcasting is widely used to distribute small control packets such as route

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.........request packets and warning packets. Numerous broadcasting protocols are proposed in literature to minimize overhead and maximize reception ratio. Different from conventional simulation based analysis methods, we theoretically analyze these protocols. Our results in [6], [7], [8] reveal the relation between broadcasting efficiency and network parameters. Furthermore, we have proposed a mobility sensitive mechanism to improve protocol performance in highly-mobile environment [9]. Broadcasting protocols based on the proposed mechanism are adaptive to nodal movement and hence reduce packet loss rate due to mobility.

end host

end host

Bottlenecklink router

Lost packects

Internet

con tro lle r xx re f

-C

Figure 1 Packets loss caused by Internet congestion Figure 2 Control configuration for a network node

Key-words: Congestion control, TCP/IP, Broadcasting, Large-scale systems.Participating Faculty: Z. P. Jiang (zjiang@control.poly.edu) and S. Panwar (panwar@catt.poly.edu)Websites: eeweb.poly.edu/faculty/jiang, http://catt.poly.edu/CATT/Research supported in part by the CATT, NSF and AFOSR.

[1] Y. Fan, Z.P.Jiang and H. Zhang, Network flow control under capacity constraints: a case study, Systems & Control Letters, Vol. 55, No. 8, pp. 681-688, 2006.[2] Y. Fan and Z. P. Jiang and S. Panwar, An adaptive control scheme for stabilizing TCP, Proc. 5th World Congress on Intelligent Control and Automation, Hangzhou, China, 2004.[3] Y. Fan and Z.P.Jiang, A nonlinear flow control scheme under capacity constraints, Acta Automatica Sinica, vol. 31, no. 1, pp. 64-74, Jan. 2005.[4] Y. Fan, Z.P. Jiang and X. Wu, A control-theoretic approach to stabilizing queues in large-scale networks, IEEE Communications Letters, Vol. 9, No. 10, pp. 951-953, 2005.[5] H. Zhang, Z.P. Jiang, Y. Fan and S. Panwar, Optimization-based flow control with improved performance, Communications in Information and Systems, vol. 4, No. 3, pp. 235-252, 2004.[6] H. Zhang and Z.P.Jiang, Analysis of two ad hoc broadcasting protocols, IEEE wireless Communications and Networking Conference (WCNC), Atlanta, GA, March, 2004. [7] H. Zhang and Z.P. Jiang, Performance analysis of broadcasting schemes in mobile ad hoc networks, IEEE Communications Letters, vol. 8, no. 12, pp. 718-720, Dec. 2004.[8] H. Zhang and Z.P. Jiang, Modeling and performance analysis of ad hoc broadcasting schemes, Performance Evaluation, Vol. 63, pp. 1196—1215, 2006. [9] H. Zhang and Z.P.Jiang, Mobility sensitive broadcast algorithms in highly mobile ad hoc networks, Ad Hoc & Sensor Wireless Networks, Vol. 3, Issues 2-3, pp. 171-196, 2007.

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.........Robust Adaptive Nonlinear Control System Designs

We have developed a powerful and flexible paradigm for dynamic high-gain based design of controllers and observers for various classes of nonlinear systems. The design technique is applicable in both the state-feedback and the output-feedback cases. The technique utilizes a state scaling generated through an appropriately designed dynamics driven by the measured outputs of the system. The resulting controller and observer are algebraically simple requiring no recursive computations and the associated Lyapunov functions have a simple scaled quadratic form. The stability analysis is based on the solution of a pair of coupled matrix Lyapunov equations. Necessary and sufficient conditions for the solvability of the coupled Lyapunov equations have been obtained in our recent results.

The approach provides a unified design procedure applicable to both lower triangular (feedback) and upper triangular (feedforward) systems and also to some classes of polynomially bounded systems without requiring any triangularity in the system structure. The controller provides strong robustness properties and allows coupling with a dynamic high-gain observer whose design is dual to that of the controller to obtain output-feedback stabilization and tracking results. This represents the first output-feedback result for feedforward systems. The controller and observer designs in the case of feedforward systems are strongly parallel to the designs in the case of strict-feedback systems suggesting that the proposed technique could allow further extensions for feedforward systems along various lines that have been hitherto investigated only for strict-feedback systems. In both, the strict feedback and the feedforward cases, a greater generality and complexity of bounds on uncertain functions in the system does not increase the complexity of the control law, the observer, and the Lyapunov function, but is instead handled through the dynamics of the scaling parameter. Furthermore, the scaling parameter dynamics can be designed to provide robustness to various perturbations including unknown parameters, additive disturbances, inverse dynamics, and appended Input-to-State Stable (ISS) dynamics. A generalized scaling technique utilizing arbitrary powers of the scaling parameter has been developed to weaken the assumptions on the system and to extend the results to non-triangular systems. Current research effort on this topic is focussed on extending the results in the following directions: 1) systems with ISS appended dynamics considering general interconnections (dependent on all states) 2) adaptive control without a priori bounds on unknown parameters 3) decentralized control for large-scale systems with each subsystem control input designed using the dynamic high-gain scaling based technique 4) disturbance attenuation 5) relaxation of assumptions by considering more general scaling patterns/ multiple scalings and more general scaling dynamics.

16

.........

Feedback interconnection of nonlinear systems

Key-words: Nonlinear control, adaptive control, robust control, high-gain designs, feedback and feedforward systems.

Participating Faculty: Farshad Khorrami (khorrami@smart.poly.edu)

Website: http://crrl.poly.edu/pub1.html

Funding Sources: NSF and ARO

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.........Development of Hardware/Software Architecture for Autonomous Unmanned VehiclesThere are many civilian (e.g., weather forecasting, traffic monitoring, police operation, fire fighting, port security) and military applications (e.g., surveillance, target identification, ordinance delivery, communication relay) for the use of unmanned autonomous vehicles (UAV). For aerial vehicles, current FAA requirements analyses identify two possible means by which UAVs may be accepted into civilian airspace: 1) requiring all UAVs to have the necessary transponder hardware to identify themselves to the control tower or 2) requiring UAVs to have autonomous obstacle avoidance systems (OAS). This latter approach of requiring OAS on UAVs is favored by the industry. An autonomous unmanned aircraft equipped with an OAS will be able to carry out a multitude of missions requiring flight to a designated target without benefit of remote piloting or any prior knowledge of the local geography. Our on-going effort is in the direction of development of a low resource OAS and its implementation on a small autonomous helicopter.

There has been much interest in UAVs in the past few decades; however, miniaturization of sensors, electronics, and fast microprocessors in the past decade have improved feasibility of small autonomous vehicles with on board OAS. Nevertheless, this is a challenging problem due to limitation of space/volume, payload capacity, power, and computational resources on board a small UAV. We have been considering several classes of UAVs, namely unmanned aerial vehicles, unmanned underwater vehicles, unmanned surface vehicles, unmanned rotary wing aircrafts. The picture of our unmanned rotary wing aircraft and a hardware-in-the-loop simulation for this test bed are given below. We have on-going efforts in regard to fixed wing aircrafts, unmanned surface vehicles (USVs), and unmanned underwater vechicles ( UUVs).

Our small autonomous helicopter and its hardware-in-the-loop implementation

Key-words: Autonomous vehicles, unmanned vehicles, obstacle avoidance, path planning, control design.

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.........

Faculty: Farshad Khorrami (khorrami@smart.poly.edu)

Website: http://crrl.poly.edu/pub1.html

Funding Sources: ARO and Industrial Funding

Nonlinear Control for Electric MotorsElectromechanical actuators have been utilized in many applications from home appliances to sophisticated guidance and control systems. Various electromechanical actuators such as

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.........electric motors, hydraulic and pnuematic actuators, smart materials (e.g., piezoceramics, magneto-restrictive materials, shape-memory alloys, electrorehological fluids, etc.) have been considered. Modeling and control design for such actuators have been and are pursued to achieve a higher level of performance. As a part of our on-going efforts, we consider modeling and control design of electric motors, namely step motors, brushless DC motors, and induction motors. These electrical motors are used in many applications; some requiring a high level of accuracy and performance such as machines used in electronics industry for assembly or semiconductor wafer probing and inspection.

To achieve high precision and bandwidth for the motors, we explore modeling of these devices to the extent needed to provide a high performance controller but at the same time amenable to model-based nonlinear designs. To this extent, we consider nonlinear and adaptive controllers to derive robust and high performance feedback controllers which is essential for applications that require high performance and accuracies. The recent nonlinear and adaptive design tools have shown to be effective in designing robust controllers achieving robust performance. We have utilized existing nonlinear tools and their extensions to design robust adaptive controllers for various motors under full state or partial state measurement (sensors less control). We have experimental test beds for such motors at the Contol/Robotics Research Laboratory at Polytechnic Institute of NYU and one such test bed is a dual axis linear stepper motor used in electronics industry. A picture of this set up is shown below.

Our dual-axis linear stepper motor experimental test bedKey-words: Electric motors, modeling, nonlinear control, adaptive control, high speed accurate step motors.

Participating Faculty: Farshad Khorrami (khorrami@smart.poly.edu)

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.........Publications: http://crrl.poly.edu/pub1.html

Funding Sources: NSF, ARO, and Industrial Funding

Book: F. Khorrami, P. Krishnamurthy, H. Melkote, Modeling and Adaptive Nonlinear Control of Electric Motors, Spring Verlag, Heidelberg, 2003.

Development of an Ultra-Accurate High-Speed Six DOF Manipulator and Other Robotic SystemsDual-axis linear motors (i.e., Sawyer motors) are utilized in various manufacturing applications such as electronics industry for assembly, packaging, lead bonding, and wafer probing. In these applications, additional degrees of freedom are attained by using other types of motors and mechanisms (e.g., geared motors or lead screws). Inherently, these additional mechanisms degrade the overall performance of the system and various motor technologies need to be employed to design a four to six degree of freedom (DOF) manipulation system (four being common for many packaging and assembly operations).

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.........We have considered the use of Sawyer motors to design a direct drive six DOF manipulator. Many 6 DOF industrial manipulators have been built by various groups and companies. The unique features of the proposed 6 DOF manipulator are that it is direct drive, uses a single motor technology, has a large work space, is high speed, and is capable of achieving high positional resolution. We have performed detailed kinematic and dynamic modeling for this type of manipulators. Furthermore, we carried out a kinematic optimization to maximize the manipulator workspace. The advocated six degree-of-freedom positioning system is a tripod structure with inextensible limbs actuated at the base by two dimensional linear stepper motors (although other types of actuators may be utilized). The proposed manipulator achieves large range of motion in all the six degrees of freedom. Furthermore, high resolution and high speed motion may be achieved in all axes. A picture of our tripod manipulator is given below.

The tripod manipulators: 6 DOF design based on dual-axis linear motors.

Key-words: Robotic manipulators, manufacturing systems, ultra-accurate robots, direct drive manipulators.

Participating Faculty: Farshad Khorrami (khorrami@smart.poly.edu)

Website: http://crrl.poly.edu/pub1.html

Funding Sources: NSF and Industrial Funding

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.........

Decentralized Control of Nonlinear Large-Scale Interconnected SystemsSeveral real-world large-scale systems can be viewed as interconnections of linear/nonlinear subsystems with constraints on information flow between the subsystems. We have addressed the decentralized control problem for large-scale systems under various sets of assumptions on the subsystem structures and interconnection topologies. We have also applied these results to a variety of large-scale systems including power networks, smart structures, and satellite formations. Our results on nonlinear control techniques have enabled us to weaken the required assumptions on the structures of the individual subsystems and also on the interconnection (or coupling) among the subsystems. We have also extended the results to include adaptations to compensate for unknown system parameters and also to provide robustness to uncertain terms and appended nonlinear dynamics. Furthermore, we have investigated techniques to achieve decentralized attenuation of disturbance inputs and provided explicit guaranteed bounds on the disturbance attenuation along with tuning strategies to achieve desired disturbance attenuation properties through the proper choice of controller parameters. Decentralization of the control may be achieved both through a centralized or a decentralized design of the decentralized controllers. In our research, both strategies have been utilized.

Decentralized control of large-scale interconnected systems

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System

Dssddsafdsadsa

Subsystem i

.........Key-words: Decentralized control, large-scale systems, nonlinear control, adaptation, interconnected subsystems.

Participating Faculty: Farshad Khorrami (khorrami@smart.poly.edu)Website: http://crrl.poly.edu/pub1.htmlFunding Sources: NSF and ARO

III.Telecommunications and Wireless

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.........Cooperative Source and Channel CodingCurrent and next generations of wireless devices and services are substantially different than the original cellular phones which could only carry voice signals. Third/fourth generation cellular and wireless local area networks are designed to support data services, image and video communications as well as voice. Multimedia signals require higher data rates and larger bandwidths than their voice counterparts. This necessitates a more efficient use of already scarce radio resources. Furthermore, guaranteeing a desired level of signal quality for image and video is especially difficult given that the wireless channel is unreliable and compressed audio and video streams are very sensitive to transmission errors.

In order to provide robust wireless multimedia communications, this research uses cooperative communication techniques along with jointly optimized source compression and channel coding strategies. Cooperation of wireless terminals is achieved by overhearing other terminal's signals and retransmitting towards the desired destination. This provides signal diversity and enables robust source-to-destination routes which can adapt to changes in the wireless environment. In order to establish the theory and practice of cooperative source and channel coding, the research plan consists of three interrelated components: Information theory of source channel cooperation; design of cooperative source and channel coding techniques with numerical/simulation studies to jointly optimize the parameters; and application of these techniques to wireless video transmission. Our initial results illustrate the benefits of layered cooperation both for idealized and practical channel codes. Layered cooperation improves the overall source distortion by providing higher reliability for important source bits via cooperation [1], [2], [3].

Participating Faculty: Elza Erkip (elza@poly.edu), Yao Wang (yao@vision.poly.edu)

Website: http://eeweb.poly.edu/~elza/, http://eeweb.poly.edu/~yao/

Funding Sources: NSF, Philips Research, CATT, WICAT

[1] D. Gunduz and E. Erkip. Joint source-channel cooperation: Diversity versus spectral efficiency. In Proceedings of 2004 International Symposium on Information Theory, Chicago, June 2004.

[2] X. Xu, Y. Wang and E. Erkip. Layered cooperation for wireless multimedia communications. To appear, Proceedings of 2004 Picture Coding Symposium, San Francisco, December 2004.

[3] X. Xu, D. Gunduz, E. Erkip and Y. Wang. Layered cooperative source and channel coding. Submitted, 2005 ICC Multimedia Communication and Home Networking Symposium, Seoul, Korea, May 2005.

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.........Cooperative Regions and Partner Choice in Coded Cooperative SystemsCooperation of mobiles provides signal diversity in wireless networks. See project “Cooperative Wireless Communications: Fundamental Principles” for a detailed description of the cooperation principle. Most work in the literature of cooperative systems assumes that a cooperating partner is already chosen and investigates the details of how cooperation should be carried out. However, it is also important to be able to choose a partner among available candidates to maximize cooperation benefits for the user or the whole system. Therefore, for a given cooperative protocol, it is desirable to know exact conditions under which cooperation is useful, how much benefits can be brought by cooperation and how the channel qualities of user-to-user and user-to-destination links affect these benefits of cooperation.

In this project we consider a coded cooperative system as described in the project “Cooperative Coding for Wireless Networks” and investigate the choice of partners to minimize the error rates. We study the partner choice problem both in an asymptotic regime when the received signal to noise ratios are high, and as a function of the locations of users [1], [2]. Our results provide simple analytical tools that identify locations of partner terminals, which we call “cooperative region,” such that if a source terminal cooperates with someone in the cooperative region, it will observe a reduction in the frame error rate with respect to no cooperation. Formulation of the cooperative region enables us to limit the search region of good partners. We also develop analytical tools that indicate the best partner from a set of available nodes that are all inside the cooperative region. Using these results, cooperation decisions can be made online without need of simulations or large look-up tables.

Participating Faculty: Elza Erkip (elza@poly.edu), Andrej Stefanov (stefanov@poly.edu)

Website: http://eeweb.poly.edu/~elza/, http://eeweb1.poly.edu/stefanov/

Funding Sources: NSF, Philips Research, CATT, WICAT

[1] Z. Lin, E. Erkip and A. Stefanov, An asymptotic analysis on the performance of coded cooperation systems. In Proceedings of 2004 Fall Vehicular Technology Conference, Los Angeles, September 2004.

[2] Z. Lin, E. Erkip and A. Stefanov, Cooperative regions for coded cooperative systems. To appear, Proceedings of 2004 GLOBECOM Communication Theory Symposium, Dallas, December 2004.

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.........Power Efficient Multimedia Wireless CommunicationsAn important lesson of cellular telephone communications is that effective management of radio resources, including transmitter power and channel bandwidth, is essential to the quality and efficiency of a network and to the utility of subscriber equipment. The theory and algorithms for radio resource management were first confined to telephone communications. Later work showed that efficient power control algorithms for cellular data transmission differ from those devised for telephony. The radio resource management problem becomes even more complex when we anticipate networks that simultaneously carry a variety of information types. Our research focuses on managing radio resources in multimedia wireless networks with an emphasis on power efficiency.

As video transmission is integrated into wireless communication systems, the theory of power control should be expanded to consider both signal processing power and transmission power when designing new algorithms, since video coding can be a significant drain on the battery of a portable wireless terminal.

This project examines the interaction of signal processing and radio transmission in the design of algorithms for managing power and bandwidth utilization in multimedia wireless networks. Initial research focused on a single portable terminal transmitting video signals to a cellular base station. The research combines theory of source coding and radio transmission, models of distortion due to source coding and channel errors in H.263 video coders, and measurements of power dissipation in equipment performing video coding. Initial results show that the optimum amount of video compression depends on the distance between the terminal and the base station. To avoid using excessive transmitter power, terminals far from a base station should employ more video compression (at the expense of additional signal processing power consumption) than terminals near a base station.

Subsequent work expands the studies of a single terminal to consider the mutual interference of several terminals, all transmitting video signals to the same CDMA base station. Work in progress considers a network in which some terminals are transmitting video signals and others are transmitting data to the base station.

Key-words: Cellular communications, power control, video compression

Participating Faculty: Elza Erip (erkip@poly.edu), David Goodman (goodman@duke.poly.edu) and Yao Wang (yao@vision.poly.edu)

Funding Sources: NSF and WICAT

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.........Website: http://eeweb.poly.edu/dream-it/

[1] Xiaoan Lu, Yao Wang, Elza Erkip and David Goodman, Minimize the Total Power Consumption for Multiuser Video Transmission over CDMA Wireless Network: a Two-step Approach, to be presented at 2005 International Conference on Acoustics Speech and Signal Processing (ICASSP2005).

[2] Xiaoan Lu, David Goodman, Yao Wang and Elza Erkip, Complexity-bounded Power Control in Video Transmission over a CDMA Wireless Network, To be presented at IEEE Globecom 2004 Conference.

[3] Xiaoan Lu, Yao Wang, Elza Erkip and David Goodman, Power Optimization of Source Encoding and Radio Transmission in Multiuser CDMA Systems, in Proceedings of 2004 International Conference on Communications (ICC), Vol. 5, pp. 3106-3110, June, 2004.

[4] Xiaoan Lu, Thierry Fernaine, Yao Wang, Modelling Power Consumption for H.263 Video Coding, in Proceedings of IEEE International Symposium on Circuits and Systems (ISCAS), Vol. 2, pp. 77-80, 2004.

[5] Xiaoan Lu, Elza Erkip, Yao Wang and David Goodman, Power efficient multimedia communication over wireless channels, IEEE Journal on Selected Areas on Communications, Special Issue on Recent Advances in Wireless Multimedia, Vol. 21, No. 10, pp. 1738-1751, Dec., 2003.

[6] Xiaoan Lu, Yao Wang and Elza Erkip, Power efficient H.263 video transmission over wireless channels, in Proceedings of 2002 International Conference on Image Processing (ICIP), Vol. 1, pp. 533-536, September 2002.

[7] Elza Erkip, Xiaoan Lu, Yao Wang, David Goodman, Total power optimization for wireless multimedia communication, in System Level Power Optimization for Wireless Multimedia Communication: Power Aware Computing, edited by R. Karri and D. Goodman, Chapter 1, Kluwer Academic Publishers, 2002.

[8] Elza Erkip, Yao Wang, David Goodman, Yuantao Wu and Xiaoan Lu, Energy efficient coding and transmission, in Proceedings of IEEE Vehicular Technology Conference (VTC), Vol. 2, pp. 1444-1448, Spring 2001, May 2001.

Peer-to-Peer Video Streaming SystemWith the widespread adoption of broadband residential access, live video streaming may be the next disruptive IP communication technology. Peer-to-Peer video streaming

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.........systems have recently emerged to provide real-time video streaming service over the Internet. Although many architectures are possible for IPTV video distribution, several mesh-pull P2P architectures have been successfully deployed in the Internet.

Measurement. In order to gain insights into P2P IPTV systems and the traffic loads they place on ISPs, we have undertaken an in-depth measurement study of one of the most popular P2P IPTV systems. The measurement results obtained through passive and active measurement bring important insights into the traffic characteristics of unstructured overlay networks formed by P2P IPTV systems. Our study provides an important input to further investigation of the impact of emerging unstructured overlay networks on traffic engineering of underlay networks. Our measurement work was published in prestigious journals, such as IEEE Transactions on Multimedia [1] and IEEE Journal on Selected Areas in Communications [2], which was awarded the Best Paper in Multimedia Communications of IEEE Communications Society (ComSoc) in 2008.

Analysis. The fundamental design philosophy of P2P systems is to efficiently utilize resources available on peers to collaboratively improve application performance at low server infrastructure cost. Video applications are extremely sensitive to streaming rate and delay. We analytically investigated various performance bounds of P2P IPTV systems. Specifically, we studied two major efficiency design issues for P2P IPTV to achieve high streaming rate and low delay. We answered the following questions: What is the maximum supportable streaming rate and peer population in a P2P IPTV system [3]? What is the minimum delay that can be achieved in P2P streaming [4]? What is the performance bound of P2P video systems offering multiple channels [5]? For each question, we derived the performance bounds, and then proposed design solutions to achieve the derived bounds. Our results have been published in highly selective conferences, such as IEEE Conference on Computer and Communications (INFOCOM) 2007 (acceptance ratio 18%) [3], and ACM Multimedia 2007 (acceptance ratio 19%) [4], INFOCOM 2009 (acceptance ratio 19%) [5]

Design. Through measurement and analysis, we obtained valuable insights on the operation of P2P streaming systems. In a project funded by Thomson corporate research lab at Princeton, we designed a Hierarchically Clustered P2P Streaming System (HCPS) to achieve a close to 100% peer uploading bandwidth utilization with dynamic peer arrivals and departures [5]. Adaptive queue based chunk scheduling algorithm is developed to make our P2P streaming system robust against network bandwidth variations [6]. In addition, we have built up a prototype system, whose performance has been validated in an Internet scale network testbed, the PlanetLab. Our experimental results were published in the Proceedings of the 28th International Conference on Distributed Computing Systems (ICDCS 2008) (acceptance ratio 15%) [7] and IEEE Transactions on Multimedia [8]. In [9], we developed VUD, a radically new P2P streaming design for systems simultaneously offering multiple channels. By decoupling the video upload and download of peers, VUD effectively solved two fundamental performance problems of the traditional P2P streaming design: excessive long channel switching delays and poor quality for unpopular channels. For Video-on-demand, we

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.........developed a new incentive mechanism that motivates peers to contribute more upload bandwidth to obtain better video playback experience [10].

Participating Faculty: Yong Liu (yongliu@poly.edu), Shiv Panwar (panwar@catt.poly.edu), Keith Ross (ross@poly.edu), CSE Dept., Yao Wang (yao@poly.edu)

Funding Sources: Thomson, Princeton, NJ Verizon, Waltham, MA Huawei, Nanjing, China

[1] Xiaojun Hei, Chao Liang, Jian Liang, Yong Liu, and Keith W. Ross, “A Measurement Study of a Large-Scale P2P IPTV System,” IEEE Transactions on Multimedia, December 2007.

[2] Xiaojun Hei, Yong Liu, and Keith Ross, “Inferring Network-Wide Quality in P2P Live Streaming Systems,” IEEE Journal on Selected Areas in Communications, the special issue on advances in P2P streaming, December 2007.

[3] Rakesh Kumar, Yong Liu, and Keith Ross, “Stochastic Fluid Theory for P2P Streaming Systems,” in Proceedings of IEEE INFOCOM, 2007.

[4] Yong Liu, “On the Minimum Delay Peer-to-Peer Video Streaming: how realtime can it be?,” in Proceedings of ACM Multimedia, 2007.

[5] Di Wu, Yong Liu and Keith Ross, "Queuing Network Models for Multi-Channel P2P Live Streaming Systems", in the Proceedings of IEEE Conference on Computer and Communications (INFOCOM) 2009

[5] Chao Liang, Yang Guo, and Yong Liu, “Hierarchically Clustered P2P Streaming System,” in Proceedings of GLOBECOM, 2007.

[6] Yang Guo, Chao Liang, and Yong Liu, “Adaptive Queue-based Chunk Scheduling for P2P Live Streaming,” in Proceedings of IFIP Networking, May 2008.

[7] Chao Liang, Yang Guo, and Yong Liu, “Is Random Scheduling Sufficient in P2P Video Streaming?,” in Proceedings of International Conference on Distributed Computing Systems, June 2008.

[8] Chao Liang, Yang Guo, and Yong Liu, “Investigating the Scheduling Sensitivity of P2P Video Streaming: an experimental study,” accepted by IEEE Transactions on Multimedia.

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.........[9] Di Wu, Chao Liang Yong Liu and Keith Ross, "View-Upload Decoupling: A Redesign of Multi-Channel P2P Video Systems", in the Proceedings of IEEE Conference on Computer and Communications (INFOCOM) Mini-Conference, 2009.

[10] Chao Liang, Zhenghua Fu, Yong Liu, and Chai Wah Wu, "iPASS: Incentivized Peer-assisted System for Asynchronous Streaming", in the Proceedings of IEEE Conference on Computer and Communications (INFOCOM) Mini-Conference, 2009

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.........Sensor ManagementThe project is to develop phenomenology and models for determining the effects of electromagnetic interference and electromagnetic compatibility (EMI/EMC) on, and as a result of adjunct ISR (intelligence, surveillance and reconnaissance) sensors for expanded US Navy’s E2-C, EA-6B and EA-18G missions. The introduction of such adjunct ISR sensors may interfere with existing and future systems (such as radar, jamming, signal processing, and communications) as well as be incompatible with existing and future EMI/EMC environments. This project will determine a range of possible interference effects and potential design methods to mitigate these effects for current and future E2-C, EA-6B, and EA-18G applications. So far, we have

created a mathematical model to simulate the effects of electromagnetic radiation on the E-2C aircraft. The model is used to identify and propose cost effective solutions to potential electromagnetic radiation problems on the E-2C aircraft that could result from increased sensor power levels.

performed analysis to quantitatively describe the currents induced over the scattering surfaces for EA-6B and EA-18G aircrafts.

developed approaches to predict the width of the Fresnel zone for various surface wave scattering paths and estimate the magnitude of the magnetic field intensity as a function of incident RF power level.

participated in Mockup EA-6B wing testing.

Key-Words: EMI, EMC

Participating Faculty: I-Tai Lu (itailu@rama.poly.edu)

[1] I-Tai Lu, “EMI and EMC Studies for Northrop Grumman’s Airplanes,” Northrop Grumman report.

[2] I-Tai Lu, “Supplementary Results to the Joint Service Center Reports,” Northrop Grumman report.

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.........Unlocking Capacity for Wireless Access Networks through Robust Cooperative Cross-Layer Design

Cooperative wireless communication refers to active users in the network assisting each other in information delivery, with the objective of gaining greater reliability and efficiency than they could obtain individually. The wireless medium allows nodes to “overhear” other transmissions. While traditional wireless networks ignore this overheard information and treat it as harmful interference, cooperative networking exploits the broadcast nature of the wireless channel by finding effective ways of pooling the overheard information.

In a distributed wireless network, it is possible to employ several relays and mimic a multiple antenna transmission system. In our research we propose a MAC layer solution that allows multiple relays to send information to the receiver at unison, using a randomized distributed space time code. The randomized space-time coding can recruit relays on the fly, thus significantly reducing signaling overhead. The cross-layer design between physical layer and MAC layer involves relay discovery and rate adaptation, and results in improvements in throughput and delay performance. The design is dynamic and can be adapted to changing network conditions. The proposed MAC scheme can be integrated into various wireless technologies such as distributed contention based networks (e.g., IEEE 802.11 BSS and ad hoc mode) as well as centralized multiple access networks (e.g., IEEE 802.16).

Participating Faculty: Shivendra Panwar (panwar@catt.poly.edu), Elza Erkip (elza@poly.edu), Pei Liu (pliu@poly.edu)

Website: http://witestlab.poly.edu/

[1] C. Nie, P. Liu, T. Korakis, E. Erkip, S. Panwar, "CoopMAX: A Cooperative MAC with Randomized Distributed Space-Time Coding for an IEEE 802.16Network", to appear, IEEE ICC 2009.

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.........[2] P. Liu and S. Panwar, “Randomized spatial multiplexing for distributed cooperative communications”, to appear, IEEE WCNC 2009.

[3] T. Korakis, M. Knox, E. Erkip, S. Panwar, "Cooperative Network Implementation Using Open Source Platforms", to appear in IEEE Communications Magazine, special issue on Cooperative and Relay Communications, February 2009.

[4] P. Liu, Y. Liu, T. Korakis, A. Scaglione, E. Erkip and S. Panwar, “Cooperative MAC for Rate Adaptive Randomized Distributed Space-time Coding”, in Proceedings of the IEEE Globecom 2008.

[5] P. Liu, C. Nie, T. Korakis and S. Panwar, “A Cooperative MAC for Distributed Space-Time Coding in an IEEE 802.16 Network”, in Proceedings of the second International Workshop on Cooperative Wireless Communications and Networking (Conet 2008), invited paper.

[6] F. Verde, T. Korakis, E. Erkip, A. Scaglione, "On avoiding collisions and promoting cooperation: catching two birds with one stone", in Proceedings of the IEEE SPAWC 2008, Recife, Brazil, July 2008.

[7] K. Sinkar, A. Jagirdar, T. Korakis, H. Liu, S. Mathur, S. Panwar, "Data Recovery in Heterogeneous Networks Using Peer’s Cooperative Networking", in Proceedings of the IEEE Secon 2008, San Francisco, CA, USA, June 2008.

[8] Z. Tao, T. Korakis, F. Liu, S. Panwar, J. Zhang, L. Tassiulas, Cooperation and Directionality: Friends or Foes?, in Proceedings of the IEEE ICC 2008, Beijing, China, May 2008.

[9] F. Liu, T. Korakis, Z. Tao, S. Panwar, A MAC-PHY Cross-Layer Protocol for Wireless Ad-Hoc Networks, IEEE WCNC 2008, Las Vegas, NV, March 2008.

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.........Cooperative Networks: Implementation of Cooperative MAC Protocols for Wireless LANs

Cooperative communications, which refer to the collaborative processing and retransmission of overheard information at stations surrounding a source, has recently gained momentum in the research community. The notion of cooperation takes full advantage of the broadcast nature of the wireless channel and creates spatial diversity, thereby achieving improvement in system robustness, capacity, delay, coverage range, and interference reduction. The innovation of cooperative communications is not confined only to the physical layer. It is available in various forms at higher protocol layers. To enable access to physical layer information and facilitate quick adaptability to mobility, it is natural to introduce the notion of cooperation into the layer directly above the PHY, namely the medium access control (MAC) layer. Thus, we have proposed several MAC layer protocols that leverage the notion of Cooperation in the MAC layer of wireless networks.

While the simulations have the ability incorporate more general models, we are still limited by the complexity of the simulation software and our limited knowledge of the wireless environment. Some specific limitations of the simulation approach in depicting a real wireless network include inaccurate representation of the wireless medium, simplification of synchronization issues that occur in wireless terminals, ignorance of several aspects such as the computational overhead.

This project intends to implement Cooperative MAC protocols and study them in a large scale programmable wireless testbed. Moving one step further than analysis/simulation and implementing cooperative protocols in a real wireless platform, would provide deep insights about the behavior of cooperative wireless networks. Through implementations and experiments, we should be able to design, improve and in some cases redesign these protocols as well as incorporate more relevant models into our theory and simulations. We will also be able to test how proposed wireless schemes scale with the size of the network.

We implement the cooperative MAC layer protocols in a Linux based platform. We use open source wireless drivers based on the 802.11 protocol and commercial wireless cards, and we modify these drivers in order to implement our algorithms. Different Linux open source drivers (HostAP, MADWiFi, Intel) are studied and tested in order to figure out their

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.........abilities and their limitations. We implement cooperative MAC layer algorithms, using in parallel more than one combination of driver-chipset. We compare different implementations by studying advantages and disadvantages of each implementation. We also study and implement cross-layer algorithms between MAC and PHY layer as well as MAC algorithms for multicast or broadcast services (e.g. video multicasting).

Participating Faculty: Shivendra Panwar (panwar@catt.poly.edu), Pei Liu (pliu@poly.edu)

Website: http://witestlab.poly.edu/

[1] S. Singh, E. Siddiqui, T. Korakis, P. Liu, S. Panwar, "A Demonstration of Cooperative coding schemes using WARP", research demo, WiNTECH 2008 MobiCom Workshop, San Francisco, CA, USA, September 2008. Third place award, WinTECH 2008 demo Contest.[2] S. Singh, E. Siddiqui, T. Korakis, P. Liu, S. Panwar, "A Demonstration of Video over a Cooperative PHY layer Protocol", research demo, ACM MobiCom 2008, San Francisco, CA, USA, September 2008.

[3] S.Singh, T.Korakis, P.Liu, S.Panwar, “A demonstration of cooperative communications using software defined radio”, research demo, TridentCom 2009, Washington D.C. USA, April 2009

[4] Jian Lin, Thanasis Korakis, Xiao Wang, Shunyuan Ye, Shivendra S. Panwar, “A demonstration of a cross-layer cooperative routing-MAC scheme in multi-hop ad-hocnetworks”, research demo, TridentCom 2009, Washington D.C. USA, April 2009

[5] Ankit Sharma, Vikas Gelara, Shashi Singh, Thanasis Korakis, Pei Liu, Shivendra Panwar, "Implementation of a Cooperative MAC protocol using a Software Defined Radio Platform", IEEE LANMAN 2008, Cluj-Napoca, Romania, September 2008.

[6] T. Korakis, Z. Tao, S. Singh, P. Liu, S. Panwar, "Implementation of a Cooperative MAC Protocol: Performance and challenges in real environment", EURASIP Journal on Wireless Communications and Networking, under review

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.........Designing Medium Access Control for Cooperative Networks

The wireless medium is a broadcast one by nature. Many nodes may overhear the transmission. In the legacy IEEE 802.11 medium access control (MAC) protocols, transmissions received by mobile stations other than the intended receiver are discarded. The broadcast nature of the wireless channels is not fully utilized. Additionally, in legacy IEEE 802.11, transmission rates of different station can vary over a wide range (e.g., from 1 to 11 Mbps in IEEE 802.11b), the high rate stations have the same channel access probability as the low rate stations, but in fact they obtain lower share of channel time than the low rate stations. This not only degrades the throughput, but also causes serious fairness problems because low data rate stations uses most of the channel time.

To exploit the broadcast nature of wireless channels, recent work on cooperative coding has shown that additional “cooperative” nodes, which overhear the transmission from sender and then participate in additional transmissions, can provide space diversity for the system. We adopt these ideas to increase the throughput of a wireless network and designed a new MAC protocol. In our proposed cooperative MAC protocol, instead of reducing the transmission rate for the nodes near the edge, we facilitate low rate stations to transmit the data packet first to an intermediate station and then to the destination, if this two-hop transmission approach is faster than direct transmission.

Figure 1: Exchange of control and data packet

In our protocol, each station in the network needs to overhear the ongoing transmission by other stations, from which they can discover their neighbors. When a station has data to transmit, it will choose one station from the neighbor list, so that if a packet was sent to the selected station first and then relayed to the destination, this two hop transmission spends the least transmission time. We also introduced a new handshake message - HR (helper-ready) in additional to the RTS (request-to-send), CTS (clear-to-send) and ACK (acknowledgement) already in 802.11. An illustration of the exchange of control and data packet is shown in Figure 1.

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.........We validated our protocol using both analytical modeling and simulation. The results show that cooperative MAC protocol can substantially enhance the network performance, in terms of the achievable throughput and average delay experienced by the data packets. Besides, the cooperative MAC improves the system fairness in the sense that it reduces the channel time occupied by low rate stations. Last, but not the least, the protocol is designed such that only minor software modification to the legacy MAC implementation is needed and backward compatibility with the legacy IEEE 802.11 system is maintained.

Participating Faculty: Shivendra Panwar (panwar@poly.edu)

Website: http://eeweb.poly.edu/coopmac/

[1] Pei Liu, Zhifeng Tao, Sathya Narayanan, Thanasis Korakis and Shivendra S. Panwar, "CoopMAC: A Cooperative MAC for Wireless LANs", IEEE Journal on Selected Areas in Communications, Special Issue on Cooperative Communications, to appear, Feburary 2007

[2] Pei Liu, Zhifeng Tao, Zinan Lin, Elza Erkip and Shivendra Panwar, "Cooperative Wireless Communications: A Cross-Layer Approach", IEEE Wireless Communications, vol.13, no.4, pp.84-92, August 2006

[3] P. Liu, Z. Tao, and S. S. Panwar, "A Cooperative MAC Protocol for Wireless Local Area Networks," in Proceedings of the IEEE International Conference on Communications (ICC), Seoul, Korea, May 2005

[4] S. Narayanan, P. Liu, S. S. Panwar, "On the advantages of multi-hop extensions to IEEE 802.11 infrastructure mode," in Proceedings of the IEEE Wireless Communications and Networking Conference (WCNC), New Orleans, LA, 2005

[5] S. Narayanan, P. Liu, S. S. Panwar, "On the advantages of multi-hop extensions to IEEE 802.11 infrastructure mode," NYMAN 2004, New York, NY, Sep. 2004

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.........

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IV. VLSI, Electronics and Power

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.........

Power Electronics for Wireless DevicesMotivation: Portable power sources such as batteries, fuel cells, and super capacitors; energy harvesting; and wireless power are candidates for powering wireless devices. Limited life span of portable sources, low output power and unreliability and low efficiency of energy harvesting methods, and inefficiency of wireless power restrict applications and decrease performance of a wireless device or network. Optimization of the power consumption characteristics of wireless devices and networks can be achieved at many levels of the system design: efficient power distribution systems, low-power demand architecture, power minimizing network algorithms, power efficient network structures, and power aware functionality specifications and requirements.

Goals: To develop power electronics topologies, control algorithms, and supervisory strategies which will minimize the effects of limited energy supply to portable wireless devices. To explore various schemes of energy harvesting and their applications in wireless devices.

Background: This project focuses on power conversion hardware for wireless devices. It is interconnected with other energy conservation WICAT efforts under the DREAM-IT umbrella. The PI has been also cooperating with ConnectionOne Center at Arizona State University and the body area network team at the University of Virginia. The efforts have resulted so far in 2 conference publications, one MS thesis, and several student research posters. Experimental verification of the research is under way with an objective of journal paper submissions.

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.........

Work Plan: Topologies of dc-dc switching converters and hybrid converters will be adapted to the needs of wireless equipment. New topologies will be developed. The work will include simulations of converters with Spice software, layout and its verification with Cadence analog suite, and manufacturing of the prototypes and experimental confirmation. It is expected that the power switching frequencies will reach the range of 100 MHz in order to decrease the size of components, improve dynamics, and ultimately increase the efficiency. This range has not been yet achieved in power electronics and poses several challenges to be investigated in this project, namely effects of parasitic, simple and power efficient implementation of the control circuitry, matching of power levels to the device needs. In the energy harvesting area, the focus will be on development of matching and power conditioning circuits to extract energy from such sources as piezoceramic generators, photovoltaic, and thermoelectric sources to achieve the highest possible energy yield.

Participating Faculty: Dariusz Czarkowski (dcz@pl.poly.edu)

[1] S. Suresh, Y. Lu, and D. Czarkowski, “100 MHz DC-DC Switching Converter with Tracking Control,” Proceedings of the IEEE IECON, Orlando, FL, November 2008.

[2] Y. Lu, S. Suresh, and D. Czarkowski, “Integrated Controller for a 100 MHz DC-DC Switching Converter,” Proceedings of the IEEE APCCAS, P. R. China, November 2008.

[3] Kwok-Kei Ching, “Analysis and design of resonant converters for energy harvesting,” MS Thesis, Polytechnic University, Brooklyn, NY, May 2008.

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.........

Analysis of Secondary Networks Having Distributed Generation SystemsDistributed Generation (DG) is predicted to play an increasing role in the electric power system of the near future. ‘DG’ means that generators of limited size (from a few kW to a few MW) will be connected to the utility distribution system at customer load levels, at distribution feeder buses, or at substation locations. It is critical that the power system impacts be assessed accurately so that these DG units can be applied in a manner that avoids causing degradation of service, such as power quality, reliability, and control of the utility system.

Fig. 1. Block diagram of the Sutton network simulated with EMTP.

This project addresses the effects of distributed generators utilizing interposed static converter systems (specifically synchronous-generator/DC-link/utility-line units) on the effect on the network-protectors of transformers during steady state operation, and also on short-circuit fault currents. The system assumed to be balanced and a per-phase analysis was used. One of Consolidated Edison of NYC networks, namely the Sutton network, has been selected as a case study as shown in Fig. 1. This network, one of the smallest in Manhattan,

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.........extends from 52nd to 57th Street and from 1st to 5th Avenue. Using EMTP, the analysis included the complete simulation of the Sutton secondary network with its 12 13.8 kV feeders, and a 9 MW static converter connected at different locations on the primary and on the secondary networks as presented in Fig. 2.

Participating Faculty: Dariusz Czarkowski (dcz@pl.poly.edu), Francisco de Leon (fdeleon@poly.edu) and Zivan Zabar (zzabar@poly.edu)

Fig. 2. Location of the MPI trailer and simulated faults on the 20m07 feeder in the Sutton network

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.........Mitigation of Voltage Disturbances Caused by Nonlinear Electrical Massive LoadsPower utilities around the world become recently more and more concern about maintaining high quality of power they provide for the customers. The reason for that is both increasing number of nonlinear devices, which cause pollution of the voltage and sensitiveness of other equipment to this pollution. Variation in the voltage level can be seen as annoying blinking of fluorescent lights in our houses, but can also interrupt proper operation of modern industrial machines or even damage some very sensitive appliance. Heavy and nonlinear loads are main sources of the voltage distortion in the electrical power grids. In the example below we can see a heavy induction motor powering a car shredder and causing variation of the voltage on its terminal. This variation transmitted through utility lines may be the reason for improper operation of the machine in the factory or can be seen in the house as a fluctuating light.

Participating Faculty: Zivan Zabar (zzabar@poly.edu) and Dariusz Czarkowski (dcz@pl.poly.edu )Collaborators: Tomasz SulawaProject is being conducted by the power group of the ECE department, Polytechnic Institute of NYU.Long Island Power Authority and KeySpan Energy sponsor this power research project to investigate and mitigate disturbances in Long Island power network.

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.........Development of a Unit Substation Demand Estimator Today electric utility companies use a wide range of computerized applications for energy management. These applications have an important role in many aspects in the power system industry. Using real-time measurements and different data analysis methods, these applications are responsible for the creation of reasonable and accurate representation of the network. These applications are also used for short term and long term load forecasting during significantly degraded operations.

A Unit Substation Demand Estimator (USDE) is needed to estimate missing data from substations in various networks across NYC and Westchester County. As a starting point for this study and the USDE development, Flatbush Brooklyn network has been chosen as the first network to be tested.

This project describes the design and implementation of a USDE. The project presents different methods for estimation of missing data measurements. Each method is tested in detail to validate the accuracy of the estimated data and an estimation process strategy is suggested.

By using the successive estimation methods and Visual Basic for Application code, a USDE application is developed. The USDE application is then tested and special tuning functions are developed to improve the estimation process and the estimation results.

Participating Faculty: Dariusz Czarkowski (dcz@pl.poly.edu ) and Zivan Zabar (zzabar@poly.edu)

Collaborator: Yariv Ten-Ami

Sponsor: Consolidated Edison Company New York, NY

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.........Mitigation Techniques to Reduce Inrush Currents of Network TransformersTransformer energization at no-load may result in a very high inrush current that is a function of the switching instant of the terminal voltage, which is totally random. In an electric distribution system, a feeder energizes many parallel-connected network transformers. Following maintenance work on the feeder, when its circuit breaker closes, it would need to withstand the combined inrush currents of all those transformers, and that peak current may cause improper operation of protective relays.

One way to reduce that inrush current would be to minimize the residual flux in all the transformer cores. The work includes an investigation, using the EMTP code, of a few possible methods of minimizing the residual flux, and the degree to which each was able to reduce the inrush current. The most applicable method is based on the known principle that demagnetization of an iron core is achieved by repeatedly reversing the voltage at the terminals of the device, while, at the same time, steadily decreasing its magnitude. At utility frequencies, 50 or 60 Hz, the power supply is relatively large. The novel idea here is the use of a very-much-lower-frequency power supply, which leads to a very small power requirement (about 2% of that for a 50 – 60 Hz unit).

The next phase would be the construction and field-testing of a prototype (pending proposal).

Participating Faculty: Zivan Zabar (zzabar@poly.edu)

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.........Secure Built-In-Self-Test (BIST)ArchitectureCrypto algorithms are being implemented in hardware to meet high throughput requirements and widely integrated as crypto accelerators in System-On-Chip (SOC) devices for secure applications ranging from tiny smart cards to high performance routers. In a secure SOC, crypto coprocessors offload intensive arithmetic computations from the host processor. A straightforward way to use BIST to test symmetric block cipher circuits is using an additional Test Pattern Generator (TPG) and Output Response Analyzer (ORA) circuits. In the test mode, the inputs to crypto data path are applied from the TPG instead of the plaintext; the outputs from crypto data path are compressed into ORA as a signature.

In a BIST architecture, the aim of TPG is to provide random inputs to Circuit under Test (CUT). Since exhaustive testing is almost impossible, for example AES data path needs 2128

test patterns, the probability distribution for test patterns determines the length of test patterns to insure an acceptable level of fault coverage. LFSR tends to produce test patterns having equal numbers of 0s and 1s on each output test pattern resulting in very long test patterns for some circuits. Weighted random pattern generators bias the distribution of 0s and 1s that makes test patterns more random thereby achieving a higher fault coverage with fewer test patterns. Strong randomness is an inherent feature of crypto algorithms. A block cipher can be considered as an instance of a random permutation over a message block under the control of a key block. In fact, the security of a block cipher can be formalized by pseudorandomness: if there is no way to distinguish the block cipher from an ideal random permutation, then the block cipher can not be attacked. One or more round operations are non-linear transformations in symmetric block ciphers. For example, in both DES and AES, the non-linear substitution is used. The randomness of several symmetric block cipher algorithms has been evaluated by National Institute of Standards and Technology (NIST).

In BIST technique, the ORA operates as a hash function; it compresses all the test results into a signature. MISR is a simple hash function and widely used as ORA. Collision probability is the most important parameter for a hash function. It is defined as the probability that two different messages have the same hash result. The smaller the collision probability is, the better the hash function. If a result sequence with faulty output vectors can also be compressed into the correct signature, such faults can not be tested. Both the quality of TPG and ORA determines the efficiency of the BIST technique. Block cipher in CBC mode is the one of the most powerful hash function widely used in message authentication code. It is computationally infeasible for such hash functions to find messages x and x’ such that x’ ≠ x and hash (x’) = hash(x). A block cipher can be used either as a TPG with more random output patterns or as an ORA with very low collision probability. Based on this key observation, we develop a BIST technique called Secure BIST to test block cipher modules. In the proposed Secure BIST technique, the output of a crypto core (ciphertext) is fed back to the input of the crypto core (plaintext) in the test mode and the signature is compressed into the output ciphertext register. The proposed Secure BIST technique incurs almost no area overhead by using a crypto module itself as both the TPG and the ORA.

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.........We validated Secure BIST on hardware implementations of Data Encryption Standard (DES) and Advanced Encryption Standard (AES). The experimental results show that Secure BIST is superior to LFSR-based BIST in terms of area overhead, fault coverage and test sequence length.

Participating Faculty: Ramesh Karri (ramesh@india.poly.edu)

[1] Bo Yang and Ramesh Karri, A Secure Built-In Self Test Technique for Crypto Modules in Secure Systems-On-Chip (SOC), submitted to IEEE Transactions on Computer.

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.........Fault Tolerant Nanoscale SystemsNew technologies based on nanoscale physical characteristics such as Resonant Tunneling Diodes, Quantum-dot Cellular Automata and molecular electronics have been researched and are being proposed as candidates for next generation device technologies. However, physical limitations at the nanoscale result in highly unreliable fabrication mechanisms which in turn translate into highly unreliable nano devices. Consequently, device failure rates in these emerging nanotechnologies are projected to be in the order of 10-3-10-1. Furthermore, the faulty behavior is time varying and hard to model. Overall, fault tolerance is an important system level design objective in these emerging nanotechnologies. In current CMOS based technologies, fault rates are static and in the range 10-9-10-7. The typical techniques for addressing reliability in CMOS technologies, namely, extensive testing at manufacturing time, and a limited amount of redundant hardware added into the circuitry for high operation time reliability, cannot be successfully applied in emerging nanotechnologies with much higher and time varying failure rates. Fundamentally, manufacturing processes and hence failure mechanisms are different and the devices per unit area are several orders of magnitude larger (~107 device/cm2 in CMOS vs ~1012 device/cm2 in emerging nanotechnologies).

This research investigates design principles for building reliable systems from unreliable nano device technologies of Quantum-dot Cellular Automata (QCA) and Negative Differential Resistance (NDR).

Fault tolerant QCA building block design

Triple Modular Redundancy (TMR) is a straightforward way to provide fault tolerance capability. However, TMR is not a good choice for designing fault tolerant QCA designs since wires, faults in wires, and wire delays dominate in this nanotechnology. We propose TMR using Shifted Operands (TMRSO) as a new approach to designing fault tolerant QCA designs with lower area overhead and better performance than straightforward TMR . This new method exploits the self-latching and adiabatic pipelining properties of QCA devices to maximize throughput of a system since more than one calculation can be in the pipeline at a given time. We have validated this concept on a two-bit adder as shown in 1.

Figure 1. A two-bit TMRSO adder

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.........Fault Tolerant NDR building block designError checking code based information redundancy approach has been regarded as a powerful fault tolerance scheme in communication and storage systems. Preliminary work in this direction has shown that, by exploiting the characteristics of certain Nanotechnology devices, linear block code based information redundancy approach can be applied to carry save based arithmetic subsystems, thus providing a promising vision of further developing a low-overhead unified fault tolerance scheme for Nanotechnology systems . 2 shows an example of fault tolerance carry save addition and the functional flow of the fault detection technique in carry-save addition using linear block coding theory.

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Figure 2. Fault tolerance carry save addition Figure 3. Instruction issue process with voter/C-unit structure

Fault tolerant nanotechnology processor designWe propose to investigate a new decentralized architecture that incorporates powerful and flexible fault tolerance strategies in the Nanotechnology environment . As a preliminary work, we have developed a fault tolerance strategy with a certain degree of decentralization in computation units that dynamically selects between hardware and time redundancy in response to the time varying fault rates in the system. Figure 3 shows a high-level view of the instruction issue process and the interaction between the voters and the C-units.

Participating Faculty: Karri Ramesh (ramesh@india.poly.edu)

Collaborators: Alex Orailoglu and Kaijie Wu

[1] T. Wei, K. Wu, R. Karri and A. Orailoglu, Fault Tolerant Quantum Cellular Array (QCA) Design using Triple Modular Redundancy with Shifted Operands, ASP-DAC 2005, to appear

[2] W. Rao, A. Orailoglu and R. Karri, Fault Tolerant Arithmetic with Applications in Nanotechnology based System, International Test Conference, pp. 472-478, October 2004

[3] W. Rao, A. Orailoglu and R. Karri, Fault Tolerant Nanoelectronic Processor Architectures, ASP-DAC 2005, to appear.

Hybrid CMOS/Nano Circuit DesignIn recent years many researchers have begun investigating the use of novel nanoelectronic devices in computer systems. The reason for such interest in nanotechnology stems from the fact that conventional technologies, specifically complementary metal oxide semiconductors (CMOS), are becoming more unreliable and difficult to work with as device feature sizes scale into the nanometer regime. These issues emerge for various reasons, including difficulty in fabricating such small devices, higher sensitivities to parameter variations and characteristics that are increasingly dependent on quantum phenomena. Novel nanoscale technologies (e.g, quantum cellular automata, single electronics and molecular electronics) offer several

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.........potential advantages where issues due to scaling may be adverted or, in some cases, even leveraged as features in new design approaches for digital circuits and architectures. Of course, conventional CMOS technology has grown strong roots in the microelectronics industry and will not be phased out completely anytime soon. Thus, the point of this research is not simply an exploration into the use of nanotechnology for digital logic and memory but also how novel nanoelectronic circuits can be integrated with conventional CMOS. Such hybrid CMOS/Nano systems (illustrated in Figure 1) aim to take advantage of each technology for optimal area utilization, performance, power consumption and design complexity [1, 2].

Figure 3. Illustrations of the concept of the CMOS/Nano design paradigm. Nanoscale devices are fabricated on top of

an oxide layer above CMOS (a) and nanoelectronic arrays could be rotated for pitch matching as proposed by Strukov

and Likharev (b).

A Hybrid CMOS/Molecular Memory DesignMany molecular electronic devices fabricated to date have exhibited a property known as hysteresis whereby a device can be made to operate with one of two possible conductivity states. Since there are two possibilities for conductance, or resistance, the device can be easily used as a memory cell where one conductivity state represents logic 1 and the other logic 0. Shown below in Figure 2 is a hybrid CMOS/molecular memory design where molecular devices are used to store data and CMOS is used to access the memory. This memory was designed from a circuit designer’s perspective considering factors such as power consumption, device parameter variations and scalability [3, 4].

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Figure 4. Illustration of molecular memory architecture complete with required CMOS circuitry.

On-Chip Characterization of Nanoscale Devices via CMOS CircuitryAn important step in developing hybrid CMOS/molecular circuits is to design CMOS circuitry for the on-chip characterization of molecular electronic devices. Work has already begun in collaboration with researchers at NIST to design and implement simple circuits (amplifiers, decoders, etc.) that can be fabricated as parts of first generation CMOS/molecular systems. Current work at Poly has consisted of the design of verification of this test circuitry while collaborators have already begun fabricating molecular electronic devices and circuits. As this project develops, hybrid CMOS/molecular circuits will not only be designed and verified using CAD tools but will also be realized and tested in the lab, bringing such novel approaches one step closer to reality [5].

Participating Faculty: Garrett S. Rose (grose@duke.poly.edu)

[1] M. R. Stan, G. S. Rose, and M. M. Ziegler, “Hybrid CMOS/Molecular Integrated Circuits,” in Moore’s Law: Beyond Planar Silicon CMOS and into the Nano Era, H. Huff, Ed., Springer, in press.

[2] M. R. Stan, G. S. Rose, and M. M. Ziegler, “Hybrid CMOS/molecular Electronic Circuits,” in Proceedings of the International Conference on VLSI Design, Hyderabad, India, Jan. 2006.

[3] G. S. Rose, Y. Yao, J. M. Tour, A. C. Cabe, N. Gergel-Hackett, N. Majumdar, J. C. Bean, L. R. Harriott, and M. R. Stan, “Designing CMOS/Molecular Memories while Considering Device Parameter Variations,” ACM Journal of Emerging Technologies in Computing, submitted.

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.........[4] G. S. Rose, A. C. Cabe, N. Gergel-Hackett, N. Majumdar, M. R. Stan, J. C. Bean, L. R. Harriott, Y. Yao, and J. M. Tour, “Design Approaches for Hybrid CMOS/Molecular Memory Based on Experimental Device Data,” in Proceedings of the ACM Great Lakes Symposium on VLSI, Philadelphia, PA, May 2006, pp. 2-7. (Best student paper.)

[5] N. Gergel-Hackett, G. S. Rose, P. Paliwoda, C. A. Hacker, C. A. Richter, “OnChip Characterization of Molecular Electronic Devices: The Design and Simulation of a Hybrid Circuit Based on Experimental Molecular Electronic Device Results,” in Proceedings of the ACM Great Lakes Symposium on VLSI, 2007, submitted.

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ECE Annual Research Report

AimsThe aim of the ECE annual research report is to report ongoing and current research activities in the ECE Department of Polytechnic Institute of NYU. By “ongoing and current” we refer to the research projects that have been undertaken by the participating faculty within past three years.

Submission guidelinesWhen to submitThe Annual Research Report will be updated once a year. All contributors should submit their new project description or any possible changes on their reports of previous year by October 15 to Dr. Z. P. Jiang at zjiang@control.poly.edu. Electronic submission is preferred.

What to submitEach submitted project description should be less than or equal to two pages and should contain enough details as suggested below:

Title of project Description of project, including motivation, project objectives, preliminary

results (if any), and potential impact of your research. Colorful figures and tables are welcome.

Key-words (not exceeding five) Names and email addresses of participating faculty, and if applicable a short list

of your collaborators. Mark the name of contact person for the project in question.

Funding resources of the project in the last three years, if applicable. References: providing the reader with a short list of selected publications on

your preliminary work. If possible, create a website for the link to any further details and progress on your ongoing project.

Please submit a WORD file with single column and 12 point font.

CopyrightSubmission of a research write-up implies that the technical contents in any form are original and that the participating faculty members of each report are responsible for accuracy of the information provided therein.

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