ael.chungbuk.ac.krael.chungbuk.ac.kr/ael/연구기초특론/참고문헌... · 2014. 1. 15. ·...

1/3/2008

1

��

1. Methods and Techniques for developing Research projects A possible vision about Theories on the development and

characterization of Scientific Research

Eugénio Oliveira- 2007 MSR- Methodologies for Scientific Research

Eugénio Oliveira- 2007/2008


��

1. Abstract of my Lectures

Understanding about ScienceScientific Methods and TechniquesWriting scientific papersEvaluating scientific papersConsulting scientific Data Bases and searching for information ( Dr. Ana Azevedo)

2. Abstract of your Work

Eugénio Oliveira- 2007 MSR- Methodologies for Scientific ResearchEugénio Oliveira- 2007 MSR- Methodologies for Scientific Research

Criticizing a scientific paperOrganizing a workshopWriting a scientific paperPresenting a scientific paper

2. Abstract of your Work

1/3/2008

2

1.1 Basic Motivations: Issues on Scientific Methods



Source: GETA and Graduate School of Electrical and Communications Engineering course: Introduction to Research Methodology, Aarne Mammela, VTT-Helsinki University of Technology,

1/3/2008

3

� ��

• Basic Characteristics:• Cumulative versus reformulating always from the principles

• However:• However:•Thomas Kuhn(Harvard, Berkley, Princeton, MIT until 91. +96) “The Structure of Scientific Revolutions” 1962.

• He points out the role in scientific research of the emergence of NEW PARADIGMS.

•A PARADIGM is defined as:

Eugénio Oliveira- 2007 MSR- Methodologies for Scientific ResearchEugénio Oliveira- 2007

•A PARADIGM is defined as:Scientific discoveries, which universally recognized during a certain period of time, create a new model for both problems and their respective solutions to be used by a community of practicians ans experimentalists

MSR- Methodologies for Scientific Research

• Paradigms support theories based on concepts, phenomena and techniques for helping on explaining new facts or information

.

� ��

• Science progresses through successive ruptures depending on the current accepted paradigms.

Paradigms correspond to “different views” over the reality which are influenced by aspects other than scientific ones.

Wittgenstein and duck-??????…


Wittgenstein and duck-??????…

Eugénio Oliveira- 2007

L.Wittgenstein “Tractatus Logico-PhilosophicusWttgeinstein’s Poker”, David Edmonds, J. Eidinow


1/3/2008

4

• Scientific interpretation (and perception) is mostly affected bySocial as well as Psychological factors.

• Does it lead to Irrationality dominating Science?

� ��

• Example of important Paradigm changes:

• Does it lead to Irrationality dominating Science?No !

• A good discussion on prevalence of science can be found in:• Kuhn, T.S.“Black-Body Theory and the Quantum Discontinuity”, 1987.

However: Paradigm change � non-cumulative Science (sometimes)


• Solar System Ptolemy's vision changed by Copernicusvision • Going from Newtonian Phisics to Quantic Physics (Uncertainty Versus Determinism..) and Relativity (Space-Time relationship).


• Karl Popper (London S. E., + 94)

� ��

• Karl Popper (London S. E., + 94)

• “The Logic of Scientific Discover”, Basic Books, 1959 (1ªEd Ing)

• Conjecture and Refutations, Harper & Row, 1968

• Idealistic. He developed a Scientific Method as an Epistomology(a way of “knowing”) independently of the intrinsic value.


• T. Khun e Feyerabend (1993) criticize this point of view showing how science is guided by value and, therefore being non-idealistic.

• This is a debate on “Consciousness over Existence”

1/3/2008

5

• “Critical Rationalism” proposal� defends “falsifiability”as a criterion for demarcating (separating) science and non-science

Induction Baaaad!!! - Falsifiability gooood!!!

� ��

• Popper argues that scientific theory will always be conjectural andprovisional.

It is not possible to confirm veracity (the truth) of a theory by meansof simply recognizing that the results of a preview already done basedon that very same theory, hold.

Induction Baaaad!!! - Falsifiability gooood!!!


on that very same theory, hold.

That Theory should only be seen as a theory not (or not yet)contradicted by facts.


Verificationism: a sentence should be either verifiable or falsifiable

Critics addressed to Verificationism:Generalization: specific instances lead to universal

assumptions

� ��

assumptions

Observation X, being an instance of Theory TIncreases the probability of Theory T being correctThe “Black Crow paradox”:

• The “Black Crow paradox”: by Hempel:“All Crows are Black" is logically equivalent to“Everything which is Non-Black is not a Crow".

∀x(Cx � Bx) � ∀ x(¬Bx � ¬Cx)

Eugénio Oliveira- 2007 MSR- Methodologies for Scientific ResearchEugénio Oliveira- 2007 MIC- Metodologias de Investigação Científica

∀x(Cx � Bx) � ∀ x(¬Bx � ¬Cx)

• Thus, If ∃ x(Cx ∧ Bx) reassures that ∀ x(Cx�Bx), Then ∃ x(¬Bx ∧ ¬Cx) reassures that ∀ x(¬Bx�¬Cx) which, being equivalent to ∀ x(Cx�Bx), this last implication would also see its probabilityof being True increased.

1/3/2008

6

• Crítics addressed to Verificationism:• Generalization: specific instances lead to

universal assumptions

• “There are Apples (non-Crows) not Black”

� ��

• “There are Apples (non-Crows) not Black” Increases the probability that the sentence“All Crows are Black” is True

• If verificationism (generalization) was acceptable, any trivial evidence would support a Theory

There are attempts to overcome this paradox..


There are attempts to overcome this paradox..“falsifiability” proposed by KP states that keepingjust the Existential assertion permit us to know that if another existential proposition that contradicts it, arrises, this falsifies the Theory T !!


��

•


1/3/2008

7

A��

An exploration Enterprise:

Christopher Columbus – the “Explorer”Motivation: ambiguous…Problem: a new way to “India”Hypothesis: over the Atlantic and not around south Africa


south AfricaExperiment: Yes he have done it !!Conclusions: ?????

A��

research: discover new knowledge

• basic research (no specific application in mind)

• applied research (ideas into operational form)

• development: systematic use of the existing


• development: systematic use of the existing knowledge

1/3/2008

8

A��

Science, Technology and Engineering [Jain97]

• science: organized or systematic body of knowledge

•• technology: application of scientific knowledge for practical ends in engineering, medicine, agriculture, etc.

•natural sciences and engineering sciences differ inthe object of study:


• natural sciences: objects in the nature• engineering sciences: objects (products, services, methods) not found in the nature, usingresults of mathematics and natural sciences

A��

Science, Technology and Engineering [Jain97]

Verification, confirmation, and justification are

Requirements for success• You have to be:

Verification, confirmation, and justification aresynonymous terms in philosophy of science. Theopposite is falsification or refutation.R. K. Jain and H. C. Triandis, Management of Research and Development Organizations: Managing the Unmanageable. John Wiley & Sons, 1997.


• You have to be:• analytical and curious, • autonomous and collaborative• criticism and tolerant

1/3/2008

9

A��

How does a researcher work?

•• make always notes in a “notebook”• make summaries on what has been learned.• make plans for the future all the time (outlines, roadmaps)• discuss, ask questions and argue (criticism)


A��

Learning carefully by induction (bottom up, generalizationfrom examples to models) [Felder88]

• Defending theories by deduction (top down, from

•

• Defending theories by deduction (top down, frommodels to results)

Break the problem down and then generalize the results(divide and conquer)

R. M. Felder and L. K. Silverman, “Learning and teaching styles in


R. M. Felder and L. K. Silverman, “Learning and teaching styles inengineering education, ”Engineering Education, pp. 674681, April 1988.

1/3/2008

10

A��

1.2 Supporting Theories


��

• Basic Characteristics

• Research involves Methodologie(s) and Techniques

• A- Methodology includes the study of several methods that areapplicable to a class of problems

• i.e., the set of processes to conduct each specific Research Project

• B- Techniques refer to the means and specific Toolsenabling relevant information acquisition, the respective data

• Research involves Methodologie(s) and Techniques


enabling relevant information acquisition, the respective dataanalysis, as well as the inferences that can be made.


1/3/2008

11

��

• A- Methodologies• depending on the MOTIVATION:

• ‘Instrumentalist Research’:• It contributes for making human intervention in Real world

environments, more effective.

• ‘Pure Research’:• It contributes to a deep theoretical understanding and for a more abstract formulation of the phenomena.

• Two major sub-categories are identified:


• Two major sub-categories are identified:• ‘Applied Research’• ‘Problem - Oriented Research’


��

• ‘Apllied Research’. • Starting from a technology (devices, specific techniques, both) use them for dealing with processes (physic, organizational, social, use them for dealing with processes (physic, organizational, social, individual,...)

• ‘Problem- Oriented Research’. • Starting with the problem description and then looking for

the adequated techniques to solve it.


1/3/2008

12

��

• Depending on the Theory underlying the Research:

• ‘Descriptive’, of all significative aspects of the domain• ‘Descriptive’, of all significative aspects of the domain

• ‘Explicative’, of the behaviour of all the phenomena

• ‘Predictive’ of the future phenomena behaviour

• ‘Prescriptive’, beyond the prediction it should also prescribe and apply Norms and processes in identified specific circumstances

(Research in IS, Electronics and Telecommunications should be of


(Research in IS, Electronics and Telecommunications should be ofthis kind)


��

• Depending on the tradition in that scientific area or Knowledge Domain:

i) ‘Traditional Scientific Research’ which is more quantitative

ii) ‘Interpretative Research’ which is more qualitative

iii) ‘Engineering-oriented Research’

• iii) most appropriated for Electronics, Telecommunications and CS


• iii) most appropriated for Electronics, Telecommunications and CS

• But do not ignore the other approaches!


1/3/2008

13

��

1.3 Positivist (classical) Research method


��

• Traditional Scientific Research is based on positivist rational thinking:

• From observations we may build up Theories trying to explain what has been observed

• Theories are expressed in Deductive form or using Axioms and Postulates which are then operated through

thinking:


Axioms and Postulates which are then operated through Logics.


1/3/2008

14

��

Do Not Forget :

• Scientific Theories, following K. Popper, are capable of generating Inferences which are, in principle, falsifiablethrough references to the real world.

• Results coming from the process of testing hypothesis give feedback to the Theory, enabling verification of its trueness or detecting possible “ab-normalities” (T.Kuhn).


trueness or detecting possible “ab-normalities” (T.Kuhn).

• Whenever the Observation comes from the Real World it is called empirical

��

• Whenever the Observation comes from the Real World it is called empiricaland it becomes relevant in two situations:

• during the formation of the theoretical knowledge through the so-calledpassive observations

• during Hypothesis verification, gathering information in a moreactive way, although guided by that same theory.


1/3/2008

15

• When we do not have a suitable Theory available, we have to pursue‘exploratory research’ where experiments and interpretation are open,not guided by a Theory and making available Empirical Knowledge that may postulate other Theories.

��

that may postulate other Theories.

• IS and Telecommunications are disciplines (scientific areas) without a given stable theory.

• They encompass applied subjects using a partial theory or co-opting a theory from “reference disciplines” such as:

• Mathematics• Information Theory (C.Shannon)


• Information Theory (C.Shannon)• Physics• “Theory of Organizations”, • “Management Sciences”, • “Computer Science”.

��

Theory ofDisciplines of Reference

Theory Axioms

2

3

AxiomsPostulatesDeductive Logic

Hypothesis

4

5

7

Real World1

1- There exists a Real World that we can Perceive.

ResearchProject

Sim

ulat

ion

6


2- Knowledge is Organized in Theories making inferences possible3- Applied Disciplines like IS or T rely on Theories of Reference of other Disciplines

4- A Research Project permits testing formal Hypothesis formulated through inferences expressed in theTheory.5- In Empirical Research, Hypothesis derived from the Theory are directly cheked in the Real Worldl

6- Testing Hypothesis through Simulation7- Results comming out of the Research give feedback to the Theory

1/3/2008

16

• Summarizing: In traditional (or conventional) Science, new Hypothesis areextracted from the existent Theory, they are tested and new results are added to that Theory.

��

added to that Theory.

• Thus, it implies the pre-existance of:• A theoretical Body of Knowledge • An explicit theoretical Framework to guide the research• Definition of what issues have to be investigated


• Definition of what issues have to be investigated• What are the explicit Hypotheses that could be refuted (falsifiability)• Method for Applied Research and well defined techniquesfor testing the Hypothesis.


1.4 Interpretative Research method

��

is concerned with trying to understand lived experience and with how participants themselves make sense of their experiences. Therefore it is concerned with the meanings which those experiences hold for the participants. IRM is phenomenological in that it wishes to explore an individual’s personal perception or account of


individual’s personal perception or account of an event or state as opposed to attempting to produce an objective record of the event or state itself. http://www.psyc.bbk.ac.uk/ipa/ (Birkback- U. London)

1/3/2008

17

• Interpretative Method (or philosophy):

��

• post-positivist• criticizes the (conventional) scientific “chimera”• declares the impossibility of objective observation • Observations and Interpretations depend on the Observer.• Addresses critics to both “hard Sciences” and Social Sciences,

• Difficulties for Objectivity:


• Concepts, Factors, relationships that can’t be accessed

��

• Researchers involvement in the research domain• Researchers involvement in the research domain

• Results depending on the researcher own perspective:- On selecting and defining the research (sub-) domain- On selecting a pre-existant theory- On setting the issues to be investigated- On setting the precise scope of the research- On selecting and defining the Variables to be instantiated- On measuring those variables possible values


- On measuring those variables possible values

• Different attitudes on all those issues may lead to many different interpretations of the same observed phenomena.


1/3/2008

18

Engineering-oriented Research Approach

1.5 Research in Engineering disciplines


• For this approach to research, technology is very important!• (devices, artefacts, practical techniques to be used)


• At least up to a certain extent is the most suitable for research in Information Systems, Electronics, Telecommunications.

• Research in IS and Telecomm is applied and problem-oriented.• Implying:

- application of suitable technology, - conceptualization: requirements, models- prototyping,


- prototyping, - implementation - demonstration of (new) technology (real world/sim)- Evaluation phase


1/3/2008

19


Observation and Theory [Wohlin99]

• In engineering an hypothesis (defined in system specifications) is usually an idea of the relationship between the cause and effect (defined in system requirements)

• Theoretical model is always only an approximation of observation


• Theoretical model is always only an approximation of observation in real world

C. Wohlin et al., Experimentation in Software Engineering: An Introduction, Springer, 1999.


In engineering we are fundamentally interested inhow efficiently the basic resources are used for aneeded performance.


1/3/2008

20

• From Dr. Leung Yee Hong Australia TC Research Institut



Research Techniques

1.6 Techniques associated to Research


1/3/2008

21

I. Non empírical Techniques

Research Techniques

B- Techniques

II. Scientific Research positivist Techniques

III. Scientific Research Interpretative Techniques

IV. Scientific Research Techniques at the positivist/interpretative boundery

V. Scientific Research Engineering-based Techniques


I. Non empirical Techniques depend on:

• Artificially created data, or• Conceptual thinking about abstractions

Research Techniques

• Conceptual thinking about abstractions

• Includes:• conceptual research based on opinion and speculation.

( argumentative and dialectic analysis)• theorem proof: This applies to mathematical abstractions:

• formal methods application, • induction, • mathematical abstractions


• mathematical abstractions• Models verification

• Simulation: • Mapping a complex environment in a simplified Model.


1/3/2008

22

• Other non empiric Techniques:

Research Techniques

• Using hypothetic future scenarios• Mapping a real scenario into Games• ...

• Reviewing the State-of-the-art and doing Meta-analysis


��

��

Eugénio Oliveira- 2007 MSR- Methodologies for Scientific ResearchMarço 2007 FEUP-LIACC / Eugénio Oliveira

1/3/2008

23

II. Scientific Research positivist Techniques(applicable to IS and other Engineering disciplines):

• Techniques for forecasting applying

Research Techniques

• Techniques for forecasting applying • regression algorithms and • time-series based algorithms to extrapolate on historic

data

• Field Experiments :• Possibly isolating and controlling a set of phenomena

to be looked at


• Laboratory Experiments:• Creating artificial setups in which phenomena, factors

and variables are isolated and controlled.


• Research approach is Descriptive/Interpretative:

III. Scientific Research Interpretativist Techniques:

Research Techniques

• Research approach is Descriptive/Interpretative: Going from empirical observations to a limited rigour analysis.Need for controlling the researcher’s perspective:

- Critical self- Examination - Revising all the postulates and biases- Varying Observations- Submission to peer reviewing


• Group Research: • frequent discussion with a group of people including

who may be affected by the application (or the technology)• Use Collaborative Work Tools.


1/3/2008

24

• Action-based Research:

- Researcher is like an “Agent” changing existent

Research Techniques

- Researcher is like an “Agent” changing existent conditions to measure the respective reaction

• Other Methods for Social Sciences(Ethnographic..)

In http://www.qual.auckland.ac.nz/ Michael Myers Ed. Ass.Inf.Sys.


In http://www.qual.auckland.ac.nz/ Michael Myers Ed. Ass.Inf.Sys.It is advocated qualitative research, for example, for IS.

We also can do (but it is not recommended) R&D just through Case-study analysis


IV. Scientific Research Techniques at the positivist/interpretativistboundery

Including:

Research Techniques

Including:- Field Work : Data related to the object of study is directly observed by the Researcher in the original context

- Questionary-based : Structured Data collection comming from interviewees

- Case Study: - Isolate and describe a relevant real-world


- Case Study: - Isolate and describe a relevant real-worldsituation,

- Gather a collection of data from multiple sources


1/3/2008

25

• Secondary Research:

Research Techniques

• Analysis starting from pre-existent documents (texts, papers, descriptions, memoirs).

• Analysis is done under new perspective and using different techniques or procedures.


v. Scientific Research Engineering-based Techniques(Informatics Engineering, IS, Electronic Engineering, Telecomm...)

• Divided into two categories:

Research Techniques

• Divided into two categories:

1- Construction Technique: • Includes Design, Project, Implementation

(or prototyping) of a system(ex: Computer program System, or physical device)

- objective:-- explicitly testing an hypothesis or


-- explicitly testing an hypothesis or -- to solve a class of problems.

- it implies:-- Existence of either a theory or a modelfor explaining the results (testing the hypothesis)


1/3/2008

26

Research Techniques

Materials and Methods

• in exact sciences materials include definitions,

• theoretical model is defined (preferably a mathematical model),including boundary conditions (define the environment)and initial conditions (define the initial values of the

• in exact sciences materials include definitions,model, and related assumptions


and initial conditions (define the initial values of theparameters of the model) [Losee01]

J. Losee, A Historical Introduction to the Philosophy of Science,4th ed. Oxford Univ. Press, 2001.


Research Techniques

• methods include:rules of analysis and rules of verification and validation

• rules of analysis follow deductive reasoning,statistical analysis and approximations (analysismust often be replaced by simulations due tomathematical tractability problems)

• the theoretical model is verified by comparing the results

rules of verification and validation


• the theoretical model is verified by comparing the results with reality (measurements with a prototype, known as hypothetical-deductive method)


1/3/2008

27

Research Techniques

• Results

• results can be analytical (deductive), from simulation, or

• use analytical results in simple limited cases to obtain referencevalues

• results can be analytical (deductive), from simulation, ormeasurement results

• it is important to present numerical results thatverify (or not) your own thesis,


values

• the value of the results depend on how well they can be generalized (bottom up approach will help you)


Conclusions (constructive technique report)

(1) “We have shown that [some] algorithms proved right…”

(2) “Our approach is simpler to implement than previous algorithms and is

Research Techniques

(2) “Our approach is simpler to implement than previous algorithms and is practically feasible …. On the theoretical side, the greatest deficiency in our results is …”

(3) “In a practical situation the advantages and limitations of our approach are…”

(4) “These results can be extended in a number of directions…”


1. What is shown by this work and its significance.2. Limitations and advantages.3. Applications of the results.4. Recommendations for further work.

1/3/2008

28

• Destructive Techniques:

Research Techniques

• To analyse a system, or a set of methods to gather new information about those technology procedures under analysis.

- Recognized information and characteristics are then reused may be in a different way


- Example: Reverse Engineering


• There are philosophies permitting the Classification of Research Methods through Paradigms or basic Epistemologies:

Phylosophy Underlying Research

I. PositivistII. Interpretative (post-positivist)III. CriticalIV. (Constructivism)

At Harvard Business School they use just the three categories


At Harvard Business School they use just the three categories


1/3/2008

29

• Positivist Method:

• Assumes that reality is objectively accessible, it can be

Philosophy Underlying Research

• Assumes that reality is objectively accessible, it can be measured and described by the observer and measured by the same observer through their instruments and devices.Tests are made making predictions possible over future phenomena

• IS research (also Telecomm research?) can be of the positivist kind (for IS, Orlikowski and Baroudi,1995)- Use math/logic formalisms


- Use math/logic formalisms- use quantifiable and measurable variables- Test an Hypothesis and make inferences from what is known.


• Interpretativist Method

• Assumes that accessing to reality is only possible through social constructions like language, consciousness and


social constructions like language, consciousness and ontologies (sharing of concepts’ meaning).

• Hermeneutics-based philosophy (based on the human understanding and text interpretation) as well as in phenomenology(describing, understanding and interpretation perceived phenomena)


phenomena)

Proposes to abolish separation between "subject“ and "object", It opposes to XIX century positivist thinking.


1/3/2008

30

• Can IS and Telecomm studies influence or be influenced by


the context?

• Here, the focus is not as much on the variables, measurements and processes as it is on interpretation of what is being the results of the test, the measurement or implementation


• Research Criticism:

• It is a radical enterprise once it tries to identify what constraintsresearch:


research:• socially, culturally,• Historically, politically, • economically, physicallytrying to emancipate science by eliminating causes for ignorance,alienation etc...

Ex: Why is it not possible to do research on X?


Ex; Why cannot we implement systems of type Y?

Habermas from Frankfurt School following the way of Adorno, Lukacs, Marcuse


1/3/2008

31

• Junk Science (?) Stories of the Past Decade

Dial “F” for Fear.


Dial “F” for Fear.

Since the 1993 Larry King Live broadcast featuring a man suing a cell phone maker claiming his wife died from a cell phone-induced brain cancer, many cell phone users have worried about phone safety.

But studies failed to identify any risk.


• Junk Science (?) Stories of the Past Decade


Powerline scare unplugged.

Fears that electric and magnetic fields (EMFs) created by power lines and appliances caused cancer started in 1978. Parents worried about power lines over schools.

Power companies worried about burying power lines. The National


Power companies worried about burying power lines. The National Academy of Sciences finally unplugged the scare in October 1996, concluding that no evidence showed EMFs presented a health hazard

1/3/2008

32

• Junk Science Stories of the Past Decade

The Lone-Tree Theory.


The Lone-Tree Theory.

It nearly took an act of Congress to get the researcher behind the notorious “hockey stick” graph, which purports to show a steep rise in global temperature in the 20th century following a millennium of stable temperatures, to release his publicly funded data and computer code.


Among other dubious presumptions, the graph is derived from data that bases climate estimates for the entire 15th century on the tree ring measurements of a single tree.


Quality of Research

1.7 Quality of Research


1/3/2008

33

Quality of Research

• Quality depends on the Objectives to reach1. To increase available (and also general) Knowledge

• Objectives and Quality criteria are internal to the discipline• Objectives and Quality criteria are internal to the discipline• RIGOUR is very critical

2. Developing Computer Systems– (Instrumentalisme)• Objectives and Criteria are external (regarding R&D)• Relevance can be measured by the impact and is of the

most importance


• Relevance Versus Rigour• Not antagonic but taken with different emphasis


• Computer Science (and other Engineering-like areas) tendency:

• Until the 80ies � conceptual (not empirical) papers

Quality of Research

• Case-studies based research is mainly descriptive concerningsimple instances and then less scientific

• Until the 80ies � conceptual (not empirical) papers dominated

• After the 80 ies� Less theoretical papers, more instantiated, less general and Knowledge less cumulative


• Empirical research is now dominated by the descriptive approaches

• Specific Models have limited capabilities for explaining aphenomen as well as little predictive power.


1/3/2008

34

Quality of Research

• Requirements for the Research in CS and TC

• Choose an appropriate Research Method:• Choose an appropriate Research Method:

• Make explicit a Body of Theory sometimes coming fromother adjacent disciplines (ex: Computer Science, Organization

• Traditional/positivist, “interpretativiste” or Engineering-oriented


other adjacent disciplines (ex: Computer Science, OrganizationTheory, Information Theory, Physics, Statistics…)

• Extend the Theory and Infer predictions to be checked(at least in the case of positivist/traditional research)


(following Björn Lisper, Datorteknik, Mälardalens högskolaVästerås, Sweeden)http://www.idt.mdh.se/kurser/ct3340/ht03/

Scientific Methods, General

Theoretical methods:

Create formal models (mathematics, logic)

Define concepts within these

Prove properties of the concepts


Prove properties of the concepts

Abstraction, hide details to make the whole more understandable(and to make it possible to prove properties of it)

Proofs of properties by deductive methods

1/3/2008

35

Empirical methods:

Perform experiments

See how it turned out

Scientific Methods, General

See how it turned out

Draw conclusions

Simulation:Start with a formal model at some "easy-to-understand" level

Make "artificial experiments" in your computer


Collect statistics and draw conclusions

In Physics:Make hypotheses about the surrounding world (theory), observe it (experiment)Relate the result of experiment to the theory

Scientific Methods

Adjust the theory if it doesn’t predict the reality well enoughTheory is used to predict the future (e.g., if a bridge will hold for acertain load, or an asteroid fall down on our heads)

Common pattern in Computing Science:The system is constructed to behave according to some theoretical model


theoretical modelDeviations are seen as construction errors rather than deficiencies in the theory (hardware error, bug in OS, : : :)

In both cases: the theory helps us understand and predict, but indifferent ways!

1/3/2008

36

Scientific MethodsTheoretical vs. Empirical Methods in Computing Science

Computing Science really has a “spectrum”, from “extremeconstructivism” to a use of theory close to the one in physics:constructivism” to a use of theory close to the one in physics:

• “Extreme constructivism”: (ideal) programming language design:

Formal semantics for the language, pure construction of modeldefining the mathematical meaning of each program

Abstraction of details to make the meaning of the language


Abstraction of details to make the meaning of the languagesimpler (for instance, assume that data structures can growarbitrarily big)Implement the language according to the semantics


One can prove formally within the model that a program is correct –valuable!

But the model does not cover all kinds of failures. E.g., hardware errors, or stack overflow (or an asteroid falling down on the computer)


asteroid falling down on the computer)

1/3/2008

37


Extreme “physics” approach: performance modeling of complex computer-and communication systemsand communication systems

Extremely hard to make analytical calculationsSimplified performance models, tested against experiments (e.g., long suites of benchmarks)

Discrepancy leads to a modified theory, as in physics


Discrepancy leads to a modified theory, as in physicsOften simulation (desire to evaluate systems before building them)


In-between: algorithm analysis

Build on some form of formal model for how the algorithm executs (meta-language with formal semantics), and some performance model (how long does a step in the algorithm take, how much memory is needed to store an entity)


1/3/2008

38


In-between: algorithm analysis

Given that the performance model is correct, one provesmathematically that the algorithm needs certain resources (time, memory) to be carried outBut the performance model is often very approximate.

Sometimes is possible to refine the performance model,


Sometimes is possible to refine the performance model, but this can make it impossible to calculate the resource needs of the algorithm

Quality of Research

• Characteristics of the Research in CS and TC(?)

• Report the S-o-A. • Report the S-o-A. • Prove you made an advancement in Knowledge• Combination of Techniques trying to compensate one’s

weaknesses with other one strengths

• Report about the object of study and the nature of the domain• Validate Data• Analysis using statistics• Extract relationships between variables


• Praticable according to the resources• Relevant results (at different levels: community,society...)• Publish• Ambitious


1/3/2008

39

• Characterístics of the research in CS:

• Research may have as an objective:

Quality of Research

• Research may have as an objective:• Building a Theory• Testing a Theory• Extending a Theory


• Other characteristics:

• Concerning Data:• Extensive

Quality of Research

• Extensive• Representative• What is Data validity (ex. temporal, precision…)• Granularity:

• Simple or agregate• Specific or large generic experiments

• Temporal Horizon:


• Temporal Horizon:

• “Snapshot” of the domain at a specific point in time• “Longitudinal cut section” (múltiple points in time)

• Methods for colecting and analising data; quantification...


1/3/2008

40

Quality of Research

1.8 Challenges


Research in CS and TC Challenges

• Challenges:• There exists shortage of theory. Mainly theories in related disciplines• Phenomena are unstable:

• Data may get old quickly, usually a snapshot that may varyPay attention to the validity period

• Organizations and Markets are always moving

• Significant cultural variations:• Different national/regional cultures imply different speed/rhythm

• When you are doing research (requirements, interaction,questionnaires, demos) you influence the domain


questionnaires, demos) you influence the domain

• Pressure for publishing during the research action


1/3/2008

41

• Pressure for technical instantiation:

• Prototyping without a theoretical ground or well defined objective


objective• Economics and business models either not known or consolidate.

• Impact of the automation and rationalization:• Depends on time dynamics concerns• Depends on who are directly affected


• Adopting a new technology may take long time• Impact on other partners, markets, standards, tools…


• Conclusions on Research actions in CS and TC

• Consider tradoff Rigour Versus Relevance• Identify challenges BEFORE starting doing research


• Be clear about conventions related with researchto be done

• Select a significative sub-domain • Define questions to be answered through that research• Select the apropriate Research Method and Techniques

(possibly a good combination of some) and justify the choice.

Whenever the selected aproach is instrumentalist, you need


Whenever the selected aproach is instrumentalist, you need to be sure about the external quality, data validation and rigouras well as:Relevance


1/3/2008

42

Other Bibliography

• D. Sternberg, How to Complete and Survive a Doctoral Thesis. • D. Sternberg, How to Complete and Survive a Doctoral Thesis. St. Martin’s Press, 1981.


ael.chungbuk.ac.krael.chungbuk.ac.kr/ael/연구기초특론/참고문헌... · 2014. 1. 15. ·...

Documents