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Residual Life Distributions From Component Degradation Signals: A Bayesian Approach, Nagi Gebraeel, Mark Lawley, Rong Li, Jennifer Ryan Jan 2005

Residual Life Distributions From Component Degradation Signals: A Bayesian Approach, Nagi Gebraeel, Mark Lawley, Rong Li, Jennifer Ryan

Research Collection Lee Kong Chian School Of Business

No abstract provided.

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Smooth Test For Density, Aurobindo Ghosh, Anil K Bera Jan 2005

Smooth Test For Density, Aurobindo Ghosh, Anil K Bera

Research Collection Lee Kong Chian School Of Business

Recently econometricians have shifted their attention from point and interval forecasts to density forecasts because at the heart of market risk measurement is the forecast of the probability density functions of various financial variables. In this paper, we propose a formal test for density forecast evaluation based on Neyman's smooth test procedure. Apart from accepting or rejecting the tested model, this approach provides specific sources (such as the location, scale and shape of the distribution) of rejection, thereby helping in deciding possible modifications of the assumed model. Our applications to S&P 500 returns indicate capturing time-varying volatility and non-gaussianity significantly …

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Partnering For Perfection: An Economics Perspective On B2b Electronic Market Strategic Alliances, Qizhi Dai, Robert J. Kauffman Jan 2005

Partnering For Perfection: An Economics Perspective On B2b Electronic Market Strategic Alliances, Qizhi Dai, Robert J. Kauffman

Research Collection School Of Computing and Information Systems

New technological innovations have made it possible for new intermediaries to create value in business processes that involve the procurement of manufacturing and services supplies. Associated with these innovations is the emergence of business-to-business (B2B) electronic markets. These act as digital intermediaries that aim to reduce the transaction costs and mitigate the risks inherent in procurement. They improve buyers’ capabilities to search for attractive prices and also serve to increase the liquidity of sellers’ products. In this chapter, the authors explore the evolution of B2B e-market firms in terms of the strategies they employ to “perfect” their value propositions and …

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Education, Technological Progress And Economic Growth, Winston T. H. Koh, Hing-Man Leung Jan 2005

Education, Technological Progress And Economic Growth, Winston T. H. Koh, Hing-Man Leung

Research Collection School Of Economics

An important role of education – and the resultant accumulation of human capital – for a less-developed economy is to facilitate technology diffusion in order for it to catch up with developed economies. This paper presents a model linking education, the accumulation of physical capital and technological progress. In the model, investment in education and the accumulation of physical capital are complementary, and intertwine with the technology progress through related effects on technology diffusion and the expansion of the technology frontier. The allocation of effort to education, the optimal savings rate and the technology gap are endogenously determined in the …

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Simultaneous Equations In Ordered Discrete Responses With Regressor-Dependent Thresholds, Myoung-Jae Lee, A. Kimhi Jan 2005

Simultaneous Equations In Ordered Discrete Responses With Regressor-Dependent Thresholds, Myoung-Jae Lee, A. Kimhi

Research Collection School Of Economics

The parameters of ordered discrete response (ODR) models are identified only up to a positive scale. In this paper, we examine the identification issue for simultaneous equations with ODR, where the well-known identification problem in simultaneous equations of recovering structural-form parameters from reduced-form parameters is compounded with the ODR identification problem. We allow the thresholds in ODR to be regressor dependent as well as constant; the former is particularly challenging because threshold parameters get mixed with regression parameters, adding one more dimension to the identification problem. We also explore a cross-equation restriction on threshold differences, under which the structural form …

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Ontology-Assisted Mining Of Rdf Documents, Tao Jiang, Ah-Hwee Tan Jan 2005

Ontology-Assisted Mining Of Rdf Documents, Tao Jiang, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

Resource description framework (RDF) is becoming a popular encoding language for describing and interchanging metadata of web resources. In this paper, we propose an Apriori-based algorithm for mining association rules (AR) from RDF documents. We treat relations (RDF statements) as items in traditional AR mining to mine associations among relations. The algorithm further makes use of a domain ontology to provide generalization of relations. To obtain compact rule sets, we present a generalized pruning method for removing uninteresting rules. We illustrate a potential usage of AR mining on RDF documents for detecting patterns of terrorist activities. Experiments conducted based on …

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Systems Analysis And Design: Should We Be Researching What We Teach?, A. Bajaj, D. Batra, A. Hevner, J. Parsons, Keng Siau Jan 2005

Systems Analysis And Design: Should We Be Researching What We Teach?, A. Bajaj, D. Batra, A. Hevner, J. Parsons, Keng Siau

Research Collection School Of Computing and Information Systems

A guiding premise of academic scholarship is that knowledge gained from first-hand research experience is disseminated to students via the classroom. However, that valuable connection is lost when professors are not researching what they teach. In this paper, we explore issues of mismatch between teaching and research in the Information Systems (IS) discipline. Specifically, while systems analysis and design (SA&D) is an integral topic in IS curricula, this topic is the research specialty of few IS professors. This situation is reflected by the low number of research publications in this area; particularly in the leading mainstream IS journals. We characterize …

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Robust Temporal Constraint Networks, Hoong Chuin Lau, Thomas Ou, Melvyn Sim Jan 2005

Robust Temporal Constraint Networks, Hoong Chuin Lau, Thomas Ou, Melvyn Sim

Research Collection School Of Computing and Information Systems

In this paper, we propose the Robust Temporal Constraint Network (RTCN) model for simple temporal constraint networks where activity durations are bounded by random variables. The problem is to determine whether such temporal network can be executed with failure probability less than a given 0 ≤ E ≤ 1 for each possible instantiation of the random variables, and if so. how one might find a feasible schedule with each given instantiation. The advantage of our model is that one can vary the value of ∊ to control the level of conservativeness of the solution. We present a computationally tractable and …

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Exploring Bit-Difference For Approximate Knn Search In High-Dimensional Databases, Bin Cui, Heng Tao Shen, Jialie Shen, Kian-Lee Tan Jan 2005

Exploring Bit-Difference For Approximate Knn Search In High-Dimensional Databases, Bin Cui, Heng Tao Shen, Jialie Shen, Kian-Lee Tan

Research Collection School Of Computing and Information Systems

In this paper, we develop a novel index structure to support effcient approximate k-nearest neighbor (KNN) query in high-dimensional databases. In high-dimensional spaces, the computational cost of the distance (e.g., Euclidean distance) between two points contributes a dominant portion of the overall query response time for memory processing. To reduce the distance computation, we first propose a structure (BID) using BIt-Difference to answer approximate KNN query. The BID employs one bit to represent each feature vector of point and the number of bit-difference is used to prune the further points. To facilitate real dataset which is typically skewed, we enhance …

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Linear Correlation Discovery In Databases: A Data Mining Approach, Cecil Chua, Roger Hsiang-Li Chiang, Ee Peng Lim Jan 2005

Linear Correlation Discovery In Databases: A Data Mining Approach, Cecil Chua, Roger Hsiang-Li Chiang, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Very little research in knowledge discovery has studied how to incorporate statistical methods to automate linear correlation discovery (LCD). We present an automatic LCD methodology that adopts statistical measurement functions to discover correlations from databases’ attributes. Our methodology automatically pairs attribute groups having potential linear correlations, measures the linear correlation of each pair of attribute groups, and confirms the discovered correlation. The methodology is evaluated in two sets of experiments. The results demonstrate the methodology’s ability to facilitate linear correlation discovery for databases with a large amount of data.

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Applying Scenario-Based Design And Claim Analysis To The Design Of A Digital Library Of Geography Examination Resources, Yin-Leng Theng, Dion Hoe-Lian Goh, Ee Peng Lim, Zehua Liu, Ming Yin, Natalie Lee-San Pang, Patricia Bao-Bao Wong Jan 2005

Applying Scenario-Based Design And Claim Analysis To The Design Of A Digital Library Of Geography Examination Resources, Yin-Leng Theng, Dion Hoe-Lian Goh, Ee Peng Lim, Zehua Liu, Ming Yin, Natalie Lee-San Pang, Patricia Bao-Bao Wong

Research Collection School Of Computing and Information Systems

This paper describes the application of Carroll’s scenario-based design and claims analysis as a means of refinement to the initial design of a digital library of geographical resources (GeogDL) to prepare Singapore students to take a national examination in geography. GeogDL is built on top of G-Portal, a digital library providing services over geospatial and georeferenced Web content. Beyond improving the initial design of GeogDL, a main contribution of the paper is making explicit the use of Carroll’s strong theory-based but undercapitalized scenario-based design and claims analysis that inspired recommendations for the refinement of GeogDL. The paper concludes with an …

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Security Of An Ill-Posed Operator Based Scheme For Image Authentication, Yongdong Wu, Robert H. Deng Jan 2005

Security Of An Ill-Posed Operator Based Scheme For Image Authentication, Yongdong Wu, Robert H. Deng

Research Collection School Of Computing and Information Systems

This letter analyzes the security of an image authentication scheme which exploits the instability of an ill-posed operator. Since the ill-posed operator produces only a limited number of authentic images regardless of the number of watermarks, an attacker can impersonate an image owner to generate authentic images at a high probability. Our experiments demonstrate that our attack is both practical and effective.

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The Effects Of Shilling On Final Bid Prices In Online Auctions, Robert J. Kauffman, Charles A. Wood Jan 2005

The Effects Of Shilling On Final Bid Prices In Online Auctions, Robert J. Kauffman, Charles A. Wood

Research Collection School Of Computing and Information Systems

An increasing number of reports of online auction fraud are of growing concern to auction operators and participants. In this research, we discuss reserve price shilling, where a bidder shills in order to avoid paying auction house fees, rather than to drive up the price of the final bid. We examine the effect that premium bids have upon the final selling price, since they are linked with reserve price shill bids. We use 10,260 eBay auctions during April 2001, and identify 919 auctions involving 322 sellers and 1583 bidders involved in concurrent auctions for the exact same item. We find …

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Technology Competition And Optimal Investment Timing: A Real Options Perspective, Robert J. Kauffman, X. Li Jan 2005

Technology Competition And Optimal Investment Timing: A Real Options Perspective, Robert J. Kauffman, X. Li

Research Collection School Of Computing and Information Systems

Companies often choose to defer irreversible investments to maintain valuable managerial flexibility in an uncertain world. For some technology-intensive projects, technology uncertainty plays a dominant role in affecting investment timing. This article analyzes the investment timing strategy for a firm that is deciding about whether to adopt one or the other of two incompatible and competing technologies.We develop a continuous-time stochastic model that aids in the determination of optimal timing for managerial adoption within the framework of real options theory. The model captures the elements of the decision-making process in such a way so as to provide managerial guidance in …

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Investing When Volatility Fluctuates, Leping Wang Dec 2004

Investing When Volatility Fluctuates, Leping Wang

Research Collection Lee Kong Chian School Of Business

No abstract provided.

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On Measuring Influence In Non-Binary Voting Games, Vincent Chua, C. H. Ueng Dec 2004

On Measuring Influence In Non-Binary Voting Games, Vincent Chua, C. H. Ueng

Research Collection School Of Economics

In this note, we demonstrate using two simple examples that generalization of the Banzhaf measure of voter influence to non-binary voting games that requires as starting position a voter’s membership in a winning coalition is likely to incompletely reflect the influence a voter has on the outcome of a game. Generalization of the Banzhaf measure that takes into consideration all possible pivot moves of a voter including those moves originating from a losing coalition will, on the other hand, result in a measure that is proportional to the Penrose measure only in the ternary case.

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High Performance P300 Speller For Brain-Computer Interface, Cuntai Guan, Manoj Thulasidas, Jiankang Wu Dec 2004

High Performance P300 Speller For Brain-Computer Interface, Cuntai Guan, Manoj Thulasidas, Jiankang Wu

Research Collection School Of Computing and Information Systems

P300 speller is a communication tool with which one can input texts or commands to a computer by thought. The amplitude of the P300 evoked potential is inversely proportional to the probability of infrequent or task-related stimulus. In existing P300 spellers, rows and columns of a matrix are intensified successively and randomly, resulting in a stimulus frequency of 1/N (N is the number of rows or columns of the matrix). We propose a new paradigm to display each single character randomly and individually (therefore reducing the stimulus frequency to 1/(N*N)). On-line experiments showed that this new speller significantly improved the …

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Values Of Mobile Commerce To Customers, Keng Siau, H. Sheng, Fiona Fui-Hoon Nah Dec 2004

Values Of Mobile Commerce To Customers, Keng Siau, H. Sheng, Fiona Fui-Hoon Nah

Research Collection School Of Computing and Information Systems

This research studies the values of m-commerce using a qualitative means-ends approach, called Value-Focused Thinking. The conceptual foundation for this research is the Work System Framework. By interviewing both current and potential m-commerce users, we captured the values of m-commerce and develop a means-ends objective network to illustrate the relationships among these values. As one of the first empirical research to assess the values of m-commerce, this research contributes to an increased understanding of m-commerce. The means-ends objective network also serves as a theoretical foundation for future research in m-commerce. For practitioners, our findings highlight the concerns and issues of …

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Automatic Model Structuring From Text Using Biomedical Ontology, Joshi R., Li X., Ramachandaran S., Tze-Yun Leong Dec 2004

Automatic Model Structuring From Text Using Biomedical Ontology, Joshi R., Li X., Ramachandaran S., Tze-Yun Leong

Research Collection School Of Computing and Information Systems

Bayesian Networks and Influence Diagrams are effective methods for structuring clinical problems. Constructing a relevant structure without the numerical probabilities in itself is a challenging task. In addition, due to the rapid rate of innovations and new findings in the biomedical domain, constructing a relevant graphical model becomes even more challenging. Building a model structure from text with minimum intervention from domain experts and minimum training examples has always been a challenge for the researchers. In the biomedical domain, numerous advances have been made which may make this dream a possibility now. We are currently trying to build a general …

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Design Lessons On Access Features In Paper, Yin-Leng Theng, Dion Hoe-Lian Goh, Ming Yin, Eng-Kai Suen, Ee Peng Lim Dec 2004

Design Lessons On Access Features In Paper, Yin-Leng Theng, Dion Hoe-Lian Goh, Ming Yin, Eng-Kai Suen, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Using Nielsen's Heuristic Evaluation, this paper reports a user study with six usability-trained subjects to evaluate PAPER's access features in assisting users to retrieve information efficiently, part of an on-going design partnership with stakeholders and designers/developers. PAPER (Personalised Adaptive Pathways for Exam Resources) is an improved version evolving from an earlier implementation of GeogDL built upon G-Portal, a geospatial digital library infrastructure. After two initial evaluations with student and teacher design partners, PAPER has evolved into a system containing a new bundle of personalized, interactive services with four modules: mock exam; personal coach (practice and review); trend analysis and performance …

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Supporting Field Study With Personalized Project Spaces In A Geographical Digital Library, Ee Peng Lim, Aixin Sun, Zehua Liu, John Hedberg, Chew-Hung Chang, Tiong-Sa Teh, Dion Hoe-Lian Goh, Yin-Leng Theng Dec 2004

Supporting Field Study With Personalized Project Spaces In A Geographical Digital Library, Ee Peng Lim, Aixin Sun, Zehua Liu, John Hedberg, Chew-Hung Chang, Tiong-Sa Teh, Dion Hoe-Lian Goh, Yin-Leng Theng

Research Collection School Of Computing and Information Systems

Digital libraries have been rather successful in supporting learning activities by providing learners with access to information and knowledge. However, this level of support is passive to learners and interactive and collaborative learning cannot be easily achieved. In this paper, we study how digital libraries could be extended to serve a more active role in collaborative learning activities. We focus on developing new services to support a common type of learning activity, field study, in a geospatial context. We propose the concept of personal project space that allows individuals to work in their personalized environment with a mix of private …

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Justilm: Few-Shot Justification Generation For Explainable Fact-Checking Of Real-World Claims, Fengzhu Zeng, Wei Gao Dec 2004

Justilm: Few-Shot Justification Generation For Explainable Fact-Checking Of Real-World Claims, Fengzhu Zeng, Wei Gao

Research Collection School Of Computing and Information Systems

Justification is an explanation that supports the verdict assigned to a claim in fact-checking. However, the task of justification generation is previously oversimplified as summarization of fact-check article authored by professional checkers. In this work, we propose a realistic approach to generate justification based on retrieved evidence. We present a new benchmark dataset called ExClaim for Explainable Claim verification, and introduce JustiLM, a novel few-shot retrieval-augmented language model to learn justification generation by leveraging fact-check articles as auxiliary resource during training. Our results show that JustiLM outperforms in-context learning (ICL)-enabled LMs including Flan-T5 and Llama2, and the retrieval-augmented model Atlas …

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The Value Of Mobile Commerce To Customers, Keng Siau, H. Sheng, Fiona Fui-Hoon Nah Dec 2004

The Value Of Mobile Commerce To Customers, Keng Siau, H. Sheng, Fiona Fui-Hoon Nah

Research Collection School Of Computing and Information Systems

This research studies the values of m-commerce using a qualitative means-ends approach, called Value-Focused Thinking. The conceptual foundation for this research is the Work System Framework. By interviewing both current and potential m-commerce users, we captured the values of m-commerce and develop a means-ends objective network to illustrate the relationships among these values. As one of the first empirical research to assess the values of m-commerce, this research contributes to an increased understanding of mcommerce. The means-ends objective network also serves as a theoretical foundation for future research in mcommerce. For practitioners, our findings highlight the concerns and issues of …

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Theoretical And Practical Complexity Of Unified Modeling Language: Delphi Study And Metrics Analyses, J. Erickson, Keng Siau Dec 2004

Theoretical And Practical Complexity Of Unified Modeling Language: Delphi Study And Metrics Analyses, J. Erickson, Keng Siau

Research Collection School Of Computing and Information Systems

Systems have become increasingly complex, and as a result development methods have become more complex as well. The unified modeling language (UML) has been criticized for the often cited and sometimes over- whelming complexity it presents to its users, and those seeking to learn to use it. Using Rossi and Brinkkemper’s (1996) complexity metrics, Siau and Cao (2001) completed a complexity analysis of UML and 36 other modeling techniques, finding that UML is indeed more complex than other techniques. Siau, Erickson and Lee (2002) proposed that Rossi and Brinkkemper’s metrics present the theoretical maximum complexity, known as theoretical complexity. This …

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On Security Notions For Steganalysis, Kisik Chang, Robert H. Deng, Feng Bao, Sangjin Lee, Hyungjun Kim, Jongin Lim Dec 2004

On Security Notions For Steganalysis, Kisik Chang, Robert H. Deng, Feng Bao, Sangjin Lee, Hyungjun Kim, Jongin Lim

Research Collection School Of Computing and Information Systems

There have been some achievements in steganalysis recently. Many people have been making strides in steganalysis. They have approached steganalysis from different angles; from information theory to complexity theory. Anderson gave a possibility that there is a provable secure steganographic system, but there had not been complexity theoretical approaches for years. In 2002, Katzenbeisser and Petitcolas defined the conditional security of steganography and gave a possibility for a practical, provable secure steganography for the first time, and Hopper et al. introduced a provable secure steganographic algorithm in the sense of complexity theory. Chang et al. also tried to define the …

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L S Penrose's Limit Theorem: Tests By Simulation, Pao-Li Chang, Vincent Chua, Moshe Machover Dec 2004

L S Penrose's Limit Theorem: Tests By Simulation, Pao-Li Chang, Vincent Chua, Moshe Machover

Research Collection School Of Economics

LS Penrose’s limit theorem (PLT) – which is implicit in Penrose [5, p. 72] and for which he gave no rigorous proof – says that, in simple weighted voting games, if the number of voters increases indefinitely while existing voters retain their weights and the relative quota is pegged, then – under certain conditions – the ratio between the voting powers of any two voters converges to the ratio between their weights. Lindner and Machover [3] prove some special cases of PLT; and conjecture that the theorem holds, under rather general conditions, for large classes of weighted voting games, various …

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Analytically Calibrated Box-Cox Percentile Limits For Duration And Event-Time Models, Zhenlin Yang, Albert K.C. Tsui Dec 2004

Analytically Calibrated Box-Cox Percentile Limits For Duration And Event-Time Models, Zhenlin Yang, Albert K.C. Tsui

Research Collection School Of Economics

This paper proposes a unified approach to constructing confidence limits for a future percentile duration or event-time. The construction is based on an analytical calibration of the Box-Cox-type “plug-in” percentile limits (PL). The performance of the calibrated Box-Cox PL is investigated using Monte Carlo experiments. Comparisons are made with PLs that are specifically designed for a particular distribution such as Weibull and lognormal. Excellent performances of the calibrated Box-Cox PL are observed. Simulation based on other popular duration models such as gamma and inverse Gaussian reveal that the proposed PL is robust against distributional assumptions and that it performs much …

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U-Commerce: Emerging Trends And Research Issues, H. Galanxhi-Janaqi, Fiona Fui-Hoon Nah Dec 2004

U-Commerce: Emerging Trends And Research Issues, H. Galanxhi-Janaqi, Fiona Fui-Hoon Nah

Research Collection School Of Computing and Information Systems

Ubiquitous commerce or u-commerce is the combination of traditional e-commerce and wireless, television, voice and silent commerce. U-commerce implies ubiquity, universality, uniqueness and unison. It is not a replacement for other types of commerce, but an extension of them. While bringing many benefits, there are challenges and impediments to overcome. Research is needed to assess the value of u-commerce and to address its related issues and challenges. Questions that need to be addressed are: What is the value of u-commerce? What are the ways to maximize the benefits and value of u-commerce? Is it the right technology and what directions …

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Vertical Sensitivity For The Information Security Health Rating Of Enterprises, Arcot Desai Narasimhalu, Nagarajan Dayasindhu, Raghavan Subramanian Dec 2004

Vertical Sensitivity For The Information Security Health Rating Of Enterprises, Arcot Desai Narasimhalu, Nagarajan Dayasindhu, Raghavan Subramanian

Research Collection School Of Computing and Information Systems

INFOSeMM Maturity model was developed jointly by SMU and Infosys. It is recognized that different industry verticals will have different levels of recommended maturity levels. This paper articulates the need for developing the industry vertical benchmarks.

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Method For Identifying Individuals, Manoj Thulasidas Dec 2004

Method For Identifying Individuals, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

A method and system for identifying a subject comprises obtaining a digitised recording of an electrocardiogram measurement of the subject to be identified, the digitised recording being a cyclic waveform having a peak amplitude. The digitised recording is normalised to reduce variations due to physiological effects, and the normalised recording is processed to determine a feature vector in the frequency domain. The distance between the determined feature vector and a predetermined feature vector is measured to identify the subject.

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