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Web Bags: Are They Useful In A Web Warehouse?, Sourav S. Bhowmick, Sanjay Kumar Madria, Wee-Keong Ng, Ee Peng Lim Nov 1998

Web Bags: Are They Useful In A Web Warehouse?, Sourav S. Bhowmick, Sanjay Kumar Madria, Wee-Keong Ng, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Sets and bags are closely related structures. A bag is different from a set in that it is sensitive to the number of times an element occurs while a set is not. In this paper, we introduce the concept of web bag in a web warehouse as a part of our Web Information Coupling System(WICS). Informally, a web bag is a web table which allows multiple occurrences of identical web tuples. Web bag helps to discover useful knowledge from a web table such as visible documents (or web sites), luminous documents and luminous paths. We formally discuss the semantics and …


Evaluating Density Forecasts With Applications To Financial Risk Management, Francis X. Diebold, Todd A. Gunther, Anthony S. Tay Nov 1998

Evaluating Density Forecasts With Applications To Financial Risk Management, Francis X. Diebold, Todd A. Gunther, Anthony S. Tay

Research Collection School Of Economics

We propose methods for evaluating density forecasts. We focus primarily on methods that are applicable regardless of the particular user’s loss function. We illustrate the methods with a detailed simulation example, and then we present an application to density forecasting of daily stock market returns. We discuss extensions for improving suboptimal density forecasts, multi-step-ahead density forecast evaluation, multivariate density forecast evaluation, monitoring for structural change and its relationship to density forecasting, and density forecast evaluation with known loss function.


A Framework For Sharing Handwritten Notes, Richard C. Davis, James Lin, Jason A. Brotherton, James A. Landay, Morgan N. Price, Bill N. Schilit Nov 1998

A Framework For Sharing Handwritten Notes, Richard C. Davis, James Lin, Jason A. Brotherton, James A. Landay, Morgan N. Price, Bill N. Schilit

Research Collection School Of Computing and Information Systems

NotePals is an ink-based, collaborative note taking application that runs on personal digital assistants (PDAs). Meeting participants write notes in their own handwriting on a PDA. These notes are shared with other participants by synchronizing later with a shared note repository that can be viewed using a desktop-based web browser. NotePals is distinguished by its lightweight process, interface, and hardware. This demonstration illustrates the design of two different NotePals clients and our web-based note browser.


Notepals: Sharing And Synchronizing Handwritten Notes With Multimedia Documents, James A. Landay, Richard C. Davis, Victor Chen, Jonathan Huang, Rebecca B. Lee, Francis Li, James Lin, Charles B. Morrey, Ben Schleimer Nov 1998

Notepals: Sharing And Synchronizing Handwritten Notes With Multimedia Documents, James A. Landay, Richard C. Davis, Victor Chen, Jonathan Huang, Rebecca B. Lee, Francis Li, James Lin, Charles B. Morrey, Ben Schleimer

Research Collection School Of Computing and Information Systems

NotePals is an ink-based, collaborative note taking application that runs on personal digital assistants (PDAs). Meeting participants write notes in their own handwriting on a PDA. These notes are shared with other participants by synchronizing later with a shared note repository that can be viewed using a desktop-based web browser. NotePals is distinguished by its lightweight process, interface, and hardware. This demonstration illustrates the design of two different NotePals clients and our web-based note browser.


A Global Object Model For Accommodating Instance Heterogeneities, Ee Peng Lim, Roger Hsiang-Li Chiang Nov 1998

A Global Object Model For Accommodating Instance Heterogeneities, Ee Peng Lim, Roger Hsiang-Li Chiang

Research Collection School Of Computing and Information Systems

To completely address database integration problems in the context of multidatabase [10] and data warehousing systems, one has to examine various integration and query requirements. Due to various reasons such as poor data quality in local databases, ongoing local database updates, and instance heterogeneities, some instance differences have to be accommodated by the integrated databases. We have therefore proposed a new object-oriented global data model, called OORA, that can accommodate attribute and relationship instance heterogeneities in the integrated database. In addition, the OORA model has been designed to allow database integrators and end users to query both the local and …


Web Warehousing System: Design And Issues, Wee-Keong Ng, Ee Peng Lim, Sourav S. Bhowmick, Sanjay Kumar Madria Nov 1998

Web Warehousing System: Design And Issues, Wee-Keong Ng, Ee Peng Lim, Sourav S. Bhowmick, Sanjay Kumar Madria

Research Collection School Of Computing and Information Systems

The World Wide Web is a distributed global information resource. It contains a large amount of information that have been placed on the web independently by different organizations and thus, related information may appear across different web sites. To manage and access heterogeneous information on WWW, we have started a project of building a web warehouse, called Whoweda (Warehouse of Web Data). Currently, our work on building a web warehousing system has focused on building a data model and designing a web algebra. In this paper, we discuss design and research issues in a web warehousing system. The issues include …


Design And Implementation Of A Maritime Conflict Prediction System, Wee-Keong Ng, Ee Peng Lim, Wen Jing Hsu, Yy Cao Oct 1998

Design And Implementation Of A Maritime Conflict Prediction System, Wee-Keong Ng, Ee Peng Lim, Wen Jing Hsu, Yy Cao

Research Collection School Of Computing and Information Systems

Maritime conflicts have serious impacts on Singapore and the surrounding region both economically and environmentally. This is particularly severe for conflicts such as collisions between large vessels or tankers carrying oil and chemicals. Thus, it is in the interests of the Maritime and Port Authority of Singapore (MPA) to avoid collisions or near-collisions among such vessels navigating through Singapore waters. Existing systems used by MPA predict potential maritime conflicts arising within a short and fixed time horizon. The system produces inconsequential warnings that are often ignored. In this paper, we describe an advanced computerbased system designed to assist in the …


Search For Sleptons In E+E- Collisions At Centre-Of-Mass Energies Up To 184 Gev Aleph Collaboration, R. Barate, Manoj Thulasidas Aug 1998

Search For Sleptons In E+E- Collisions At Centre-Of-Mass Energies Up To 184 Gev Aleph Collaboration, R. Barate, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

The data collected by the ALEPH experiment at LEP at centre–of–mass energies around 183 GeV are analysed to search for sleptons, the partners of leptons in supersymmetric theories. The previously published search for acoplanar leptons and missing energy has been updated. New searches have been developed to cover a wider range of slepton signals. These include single electrons, acoplanar leptons accompanied by two photons plus missing energy as well as particles with lifetime. No evidence for the production of any such particles is found. Slepton mass limits are reported within gravity mediated and gauge mediated SUSY breaking scenarios.


The Forward-Backward Asymmetry For Charm Quarks At The Z, R. Barate, Manoj Thulasidas Aug 1998

The Forward-Backward Asymmetry For Charm Quarks At The Z, R. Barate, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

From 1.4 million hadronic Z decays collected by the ALEPH detector at LEP, an enriched sample of Z → cc̄ events is extracted by requiring the presence of a high momentum D∗±. The charm quark forward-backward charge asymmetry at the Z pole is measured to be AFB0.c = (8.0 ± 2.4) % corresponding to an effective electroweak mixing angle of sin2θWeff = 0.2302 ± 0.0054.


Scalar Quark Searches In E+E- Collisions At √S = 181 - 184 Gev, Barate, R.; Et Al., M. Thulasidas Aug 1998

Scalar Quark Searches In E+E- Collisions At √S = 181 - 184 Gev, Barate, R.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

Searches for scalar top, scalar bottom and degenerate scalar quarks have been performed with data collected with the ALEPH detector at LEP. The data sample consists of 57 pb−1 taken at s = 181–184 GeV. No evidence for scalar top, scalar bottom or degenerate scalar quarks was found in the channels t̃→cχ, t̃→bℓν̃, b̃→bχ, and q̃→qχ. From the channel t̃→cχ a limit of 74 GeV/c2has been set on the scalar top quark mass, independent of the mixing angle. This limit assumes a mass difference between the t̃ and the χ in the range 10–40 GeV/c2. From the channel t̃→bℓν̃ the …


Modelling Medical Decisions In Dynamol: A New General Framework Of Dynamic Decision Analysis, Tze-Yun Leong, Cungen Cao Aug 1998

Modelling Medical Decisions In Dynamol: A New General Framework Of Dynamic Decision Analysis, Tze-Yun Leong, Cungen Cao

Research Collection School Of Computing and Information Systems

Dynamic decision analysis concerns decision problems in which both time and uncertainty are explicitly considered. We present a new dynamic decision analysis framework, called DynamoL, that supports graphical presentation of the decision factors in multiple perspectives. To alleviate the difficulty in assessing conditional probabilities over time in dynamic decision models, DynaMoL incorporates a Bayesian learning system to automatically learn the probabilistic parameters from large medical databases. We describe the DynaMoL modeling and learning architecture through a medical decision problem on the optimal follow-up schedule for patients after curative colorectal cancer surgery. We also show that the modeling experience and results …


Method Engineering For Web Information Systems Development: Challenges And Issues, Keng Siau Aug 1998

Method Engineering For Web Information Systems Development: Challenges And Issues, Keng Siau

Research Collection School Of Computing and Information Systems

Despite the rapid advancement of technology in the last few decades, accurate, on-time, and on-budget completion of information systems development projects is still a vision rather than a reality. The software crisis is still very much alive almost forty years after it was first defined. The sudden popularity of Internet and electronic commerce pose a new challenge to the software engineering community. With the increasing importance of electronic commerce and $3 billion in sales expected to take place over cyberspace by the year 2000, organizations will be competing to design and develop web-based applications. However, existing information modeling methods might …


A Typology For Understanding The Role Of Information As A Source Of Value Creation In The Emerging Information Economy, J. Mcintosh, Keng Siau Aug 1998

A Typology For Understanding The Role Of Information As A Source Of Value Creation In The Emerging Information Economy, J. Mcintosh, Keng Siau

Research Collection School Of Computing and Information Systems

Today’s economy is increasingly driven by the integration of information in many aspects of business. Greater information intensity in industries such as hospital supply and express package delivery is causing a fundamental transformation in the way firms conduct business, the menu of competitive choices that they are faced with, and the need to continuously keep ahead of competitors. Information driven businesses appear to adopt several competitive or operating innovations. These include: mass customization or the creation of customized products which offer virtually individualized products to customers in mass markets (Pine, 1993); disintermediation or the creation of direct links between producers …


Searching For Periods Of Volatility: A Study Of The Behavior Of Volatility In Thai Stocks, Theodore Bos, David K. Ding, Thomas A. Fetherston Aug 1998

Searching For Periods Of Volatility: A Study Of The Behavior Of Volatility In Thai Stocks, Theodore Bos, David K. Ding, Thomas A. Fetherston

Research Collection Lee Kong Chian School Of Business

This paper improves the precision of the useful new procedure of Inclán and Tiao (1994) that estimates variance shift points in a time series. It accomplishes this by incorporating the evidence of Bos and Fetherston (1992) that the linear Brown, Durbin, and Evans (Brown et al., 1975) critical CUSUM of squares boundaries [used by Inclán and Tiao] produce an understatement of instability at the data end points. This is solved by Tanizaki (1995) which, like Bos and Fetherston (1992) and Bos and Fetherston (1995), uses the fact that the CUSUM of squares statistic follows a beta distribution. This study uses …


Information Systems And Economics, Robert J. Kauffman, Frederick J. Riggins Aug 1998

Information Systems And Economics, Robert J. Kauffman, Frederick J. Riggins

Research Collection School Of Computing and Information Systems

Do big dollar expenditures on information systems pay off? Friction-free: is that what we really want markets to be? Is it time for consumers to say goodbye to fixed pricing? The Internet creates an environment in which the cost of buyer-seller interactions is cheaper than ever, and consumers can participate in the price-setting process—revealing their willingness to pay—making it the most efficient one-on-one selling environment anywhere, approaching the efficiency of the financial markets. In fact, such transformation is evident throughout the information economy. We see it in the approximately 1,000% annual network growth rates expected by some Internet service providers’ …


Join Processing In Web Databases, Sourav S. Bhowmick, Wee-Keong Ng, Ee Peng Lim Aug 1998

Join Processing In Web Databases, Sourav S. Bhowmick, Wee-Keong Ng, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Recently, there has been increasing interests in data models and query languages for unstructured data in the World Wide Web. When web data is harnessed in a web warehouse, new and useful information can be derived through appropriate information manipulation. In our web warehousing project, we introduce a new operator called the web join. Like its relational counterpart, web join combines information from two web tables to yield a new web table. This paper discusses various issues in web join such as join semantics, joinability, and join evaluation.


A Measurement Of The Inclusive B → Sγ Branching Ratio, R. Barate, Manoj Thulasidas Jun 1998

A Measurement Of The Inclusive B → Sγ Branching Ratio, R. Barate, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

The avour changing neutral current decay b ! s has been detected in hadronic Z decays collected by ALEPH at LEP. The signal is isolated in lifetime-tagged b b events by the presence of a hard photon associated with a system of high momentum and high rapidity hadrons. The background processes are normalised from the data themselves. The inclusive branching ratio is measured to be (3:11 0:80stat 0:72syst) 104 ; consistent with the Standard Model expectation via penguin processes


Database Selection Techniques For Routing Bibliographic Queries, Ee Peng Lim, Wee-Keong Ng, Jian Xu, Yinyan Cao Jun 1998

Database Selection Techniques For Routing Bibliographic Queries, Ee Peng Lim, Wee-Keong Ng, Jian Xu, Yinyan Cao

Research Collection School Of Computing and Information Systems

No abstract provided.


Querying Structured Web Resources, Ee Peng Lim, Cheng Hai Tan, Boon Wan Lim, Wee-Keong Ng Jun 1998

Querying Structured Web Resources, Ee Peng Lim, Cheng Hai Tan, Boon Wan Lim, Wee-Keong Ng

Research Collection School Of Computing and Information Systems

To provide query facilities over Web resources, several web search engines such as Yahoo, Altavista, Infoseek, etc. have been developed. Most prominently, web search engines have been used to index all web pages on the Internet. The queries supported by these search engines are mainly designed to reveal web pages that meet the search criteria specified by the users. In this way, the search engines have been used as some kind of discovery tools. The queries supported are known as discovery queries. On the other hand, a web search engine can also be used to index and support queries over …


The New Aleph Silicon Vertex Detector, D. Creanza, Manoj Thulasidas May 1998

The New Aleph Silicon Vertex Detector, D. Creanza, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

The ALEPH collaboration, in view of the importance of effective vertex detection for the Higgs boson search at LEP 2, decided to upgrade the previous vertex detector. Main changes were an increased length (+/- 20 cm), a higher granularity for r phi view (50 mu m), a new preamplifier (MX7 rad hard chip), a polymide (upilex) fan-out on z side to carry the signals from the strips to the front-end electronics outside the fiducial region reducing consequently the passive material in the central region by a factor of two. The detector, the running experience and its performance will be described. …


Resonant Structure And Flavour Tagging In The Bπ± System Using Fully Reconstructed B Decays, Barate, R.; Et Al., M. Thulasidas Apr 1998

Resonant Structure And Flavour Tagging In The Bπ± System Using Fully Reconstructed B Decays, Barate, R.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

No abstract provided.


Resource-Constrained Project Scheduling: A Survey Of Recent Developments, Willy Herroelen, Bert De Reyck, Erik Demeulemeester Apr 1998

Resource-Constrained Project Scheduling: A Survey Of Recent Developments, Willy Herroelen, Bert De Reyck, Erik Demeulemeester

Research Collection Lee Kong Chian School Of Business

We review recent advances in dealing with the resource-constrained project scheduling problem using an efficient depth-first branch-and-bound procedure, elaborating on the branching scheme, bounding calculations and dominance rules, and discuss the potential of using truncated branch-and-bound. We derive conclusions from the research on optimal solution procedures for the basic problem and subsequently illustrate extensions to a rich and realistic variety of related problems involving activity preemption, the use of ready times and deadlines, variable resource requirements and availabilities, generalized precedence relations, time/cost, time/resource and resource/resource trade-offs and non-regular objective functions.


Functional Relations Among Constructs In The Same Content Domain At Different Levels Of Analysis: A Typology Of Composition Models, David Chan Apr 1998

Functional Relations Among Constructs In The Same Content Domain At Different Levels Of Analysis: A Typology Of Composition Models, David Chan

Research Collection School of Social Sciences

Composition models specify the functional relationships among phenomena or constructs at different levels of analysis (e.g., individual level, team level, organizational level) that reference essentially the same content but that are qualitatively different at different levels (M. T. Hannan, 1971, K. H. Roberts, C. L. Hulin, & D. M. Rousseau, 1978, D. M. Rousseau, 1985). Specifying adequate composition models is a critical component of good multilevel research. A typology of composition models is proposed to provide a framework for organizing, evaluating, and developing constructs and theories in multilevel research. Five basic forms of composition are described and illustrated. Implications of …


Measurement Of The W Mass By Direct Reconstruction In E+E- Collisions At 172 Gev, Barate, R.; Et Al., M. Thulasidas Mar 1998

Measurement Of The W Mass By Direct Reconstruction In E+E- Collisions At 172 Gev, Barate, R.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

No abstract provided.


Measurement Of Triple Gauge-Boson Couplings At 172 Gev, Barate, R.; Et Al, M. Thulasidas Mar 1998

Measurement Of Triple Gauge-Boson Couplings At 172 Gev, Barate, R.; Et Al, M. Thulasidas

Research Collection School Of Computing and Information Systems

The triple gauge-boson couplings, αWΦ, αW and αBΦ, have been measured using 34 semileptonically and 54 hadronically decaying W+W− candidate events. The events were selected in the data recorded during 1996 with the ALEPH detector at 172 GeV, corresponding to an integrated luminosity of 10.65 pb−1. The triple gauge-boson couplings have been measured using optimal observables constructed from kinematic information of W+W− events. The results are in agreement with the Standard Model expectation.


A Signcryption Scheme With Signature Directly Verifiable By Public Key, Feng Bao, Robert H. Deng Feb 1998

A Signcryption Scheme With Signature Directly Verifiable By Public Key, Feng Bao, Robert H. Deng

Research Collection School Of Computing and Information Systems

Signcryption, first proposed by Zheng, is a cryptographic primitive which combines both the functions of digital signature and public key encryption in a logical single step, and with a computational cost significantly lower than that needed by the traditional signature-then-encryption approach. In Zheng's scheme, the signature verification can be done either by the recipient directly (using his private key) or by engaging a zero-knowledge interative protocol with a third party, without disclosing recipient's private key. In this note, we modify Zheng's scheme so that the recipient's private key is no longer needed in signature verification. The computational cost of the …


Four-Jet Final State Production In E+E- Collisions At Centre-Of-Mass Energies Ranging From 130 To 184 Gev, R. Barate, Manoj Thulasidas Feb 1998

Four-Jet Final State Production In E+E- Collisions At Centre-Of-Mass Energies Ranging From 130 To 184 Gev, R. Barate, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

The four jet topology is analysed in the ALEPH data taken between November 1995 and October 1997, at centre-of-mass energies ranging from 130 to 184 GeV. While an unexpected accumulation of events with a dijet mass sum around 105 GeV/c 2 had been observed during the first run in 1995 at 130/136 GeV, corresponding to an integrated luminosity of 5.7 pb1 , no significant dierences between data and standard model prediction is seen, either in the high energy runs (81.1 pb1 taken at centre-of-mass energies from 161 to 184 GeV) or in the 7.1 pb1 recorded during a new short …


A Visual Object-Relationship Query Language For User-Database Interaction, Keng Siau Feb 1998

A Visual Object-Relationship Query Language For User-Database Interaction, Keng Siau

Research Collection School Of Computing and Information Systems

User–database interaction has a direct and immediate effect on the effectiveness and efficiency of database end users. Traditional query languages like SQL and QBE require end users to understand the underlying data structure in the database. This is a burden on end users, especially novice end users who have little technical knowledge or understanding of database. To alleviate the need for end users to know the logical database organization, this paper proposes the use of an object–relationship (OR) model and a formal high-level visual query language as the interface. Using this interface, end users communicate only domain knowledge with the …


Search For Evidence Of Compositeness At Lep I, R. Barate, M. Thulasidas Jan 1998

Search For Evidence Of Compositeness At Lep I, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

Extensive searches for evidence of compositeness of quarks and leptons have been made in the complete set of ALEPH data from LEP running at the Z peak. These include searches for radiative and weak decays of excited fermions, produced either in pairs or singly, and a scalar partner of the Z. Coupling and branching ratio limits deduced from these searches are presented.


An Upper Limit On The Τ Neutrino Mass From Three- And Five-Prong Tau Decays, R. Barate, M. Thulasidas Jan 1998

An Upper Limit On The Τ Neutrino Mass From Three- And Five-Prong Tau Decays, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

A bound on the tau neutrino mass is established using the data collected from 1991 to 1995 at s√≃mZ with the ALEPH detector. Two separate limits are derived by fitting the distribution of visible energy vs invariant mass in τ−→2π−π+ντ and τ−→3π−2π+(π0)ντ decays. The two results are combined to obtain a 95% confidence level upper limit of 18.2 MeV/c2 on the mass of the tau neutrino.