Physical Sciences and Mathematics Commons^™

Inclusive Production Of Neutral Pions In Hadronic Z Decays, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

A measurement of the inclusive production of π0 mesons in hadronic Z decays is presented and compared to Monte Carlo model predictions. The analysis is based on approximately 2 million hadronic events recorded with the ALEPH detector at LEP at a centre-of-mass energy of ⊡s = 91.2 GeV. Neutral pions are reconstructed using photons measured in the electromagnetic calorimeter and photons from conversion pairs. The inclusive π0 momentum spectrum is measured in the range 0.025 x p = p/p beam 0 per hadronic Z is found to be 4.80 ± 0.07(stat) ± 0.31(sys). The differential inclusive π0 cross section is …

Searches For Scalar Top And Scalar Bottom Quarks At Lep2, Barate, R.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

Searches for scalar top and bottom quarks have been performed with data collected by the ALEPH detector at LEP. The data sample consists of 21.7 pb−1 taken at √ s = 161, 170, and 172 GeV and 5.7 pb−1 taken at √ s = 130 and 136 GeV. No evidence for scalar top quarks or scalar bottom quarks was found in the channels ˜t → cχ, ˜t → bℓν˜, and b˜ → bχ. For the channel ˜t → cχ a limit of 67 GeV/c 2 has been set on the scalar top quark mass, independent of the mixing angle between …

Tertiary Storage In Multimedia Systems: Staging Or Direct Access?, Hwee Hwa Pang

Research Collection School Of Computing and Information Systems

Multimedia applications that are required to manipulate large collections of objects are becoming increasingly common. Moreover, the size of multimedia objects, which are already huge, are getting even bigger as the resolution of output devices improve. As a result, many multimedia storage systems are not likely to be able to keep all of their objects disk-resident. Instead, a majority of the less popular objects have to be off-loaded to tertiary storage to keep costs down. The speed at which objects can be accessed from tertiary storage is thus an important consideration. In this paper, we propose an adaptive data retrieval …

Updated Measurement Of The Τ Lepton Lifetime, R. Barate, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

A new measurement of the mean lifetime of the τ lepton is presented. Three different analysis methods are applied to a sample of 90000 τ pairs, collected in 1993 and 1994 with the ALEPH detector at LEP. The average of this measurement and those previously published by ALEPH is ττ = 290.1±1.5±1.1fs.

Search For The Standard Model Higgs Boson In E+E- Collisions At √S = 161, 170 And 172 Gev, Barate, R.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

The reaction e+ e ! HZ is used to search for the Standard Model Higgs boson. The data sample consists of integrated luminosities of 10:9 pb1 , 1:1 pb1 , and 9:5 pb1 collected by the ALEPH experiment at LEP during 1996, at centre-of-mass energies of 161, 170 and 172 GeV, respectively. No candidate events were found, in agreement with the expected background of 0.84 events from all Standard Model processes. This search results in a 95% C.L. lower limit on the Higgs boson mass of 69:4 GeV=c2 . When combined with earlier ALEPH searches performed at energies at and …

Search For Sleptons In E+E- Collisions At Centre-Of-Mass Energies Of 161 Gev And 172 Gev, R. Barate, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

The data recorded by the ALEPH experiment at LEP at centre–of–mass energies of 161 GeV and 172 GeV were analysed to search for sleptons, the supersymmetric partners of leptons. No evidence for the production of these particles was found. The number of candidates observed is consistent with the background expected from four–fermion processes and γγ–interactions. Improved mass limits at 95% C.L. are reported.

A Measurement Of The Qcd Colour Factors And A Limit On The Light Gluino, Barate, R.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

Using data collected from 1992 to 1995 with the ALEPH detector at LEP, a measurement of the colour factor ratios CA/CF and TF /CF and the strong coupling constant αs = CFαs(MZ)/(2π) has been performed by fitting theoretical predictions simultaneously to the measured differential two-jet rate and angular distributions in four-jet events. The result is found to be in excellent agreement with QCD, {fx4-1} Fixing CA/CF and TF/CF to the QCD values permits a determination of αs(MZ) and ηf, the number of active flavours. With this measurement the existence of a gluino with mass below 6.3 GeV/c2 is excluded at …

From Contemporary Workflow Process Automation To Adaptive And Dynamic Work Activity Coordination And Collaboration, Amit P. Sheth

Kno.e.sis Publications

The article outlines a research agenda for researchers in the area of workflow. We believe that today's workflow systems should evolve to what is termed as work coordination and collaboration systems (WCCSs). A WCCS will: (a) adapt to various changes in the organization (including its interactions with external organizations) and the organizational processes by being able to change the process definitions as well as change the processes and component activities while they are being enacted or executed; and (b) support a unified framework for managing coordination, collaboration, and information based decision making activities that naturally occur as part of organizational …

Measurement Of The Transverse Spin Correlations In The Decay Z → Τ+Τ-, Barate, R.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

A measurement of the transverse-transverse, CTT, and transverse-normal CTN, τ spin correlations in the decay Z0 → τ+ τ− is presented based on the aplanarity angle of the decay products of both taus. Based on 80 pb−1 of data collected by ALEPH[1] in 1992, 1993 and 1994 on the peak of the Z resonance, the results are: CTT = 1.00 ± 0.14(stat) ± 0.04(syst), CTN =−0.08 ± 0.14(stat) ± 0.02(syst). These values are in agreement with the Standard Model predictions, CTT = 0.989 and CTN = 0.

Measurement Of The Branching Fraction For D0 → K-Π+, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

The branching fraction for D0 → K−π+ is measured with the statistics collected by ALEPH from 1991 to 1994. The method is based on the comparison between the rate for the reconstructed D∗+→ D0π+, D0 → K−π+ decay chain and the rate for inclusive soft pion production at low transverse momentum with respect to the nearest jet. The result is B(D0 → K−π+0 = (3.90 ± 0.09 ± 0.12)%

Search For The Bc Meson In Hadronic Z Decays, R. Barate, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

A search for the Bc meson decaying into the channels Jψπ+ and Jψℓ+νℓ (ℓ = e or μ) is performed in a sample of 3.9 million hadronic Z decays collected by the ALEPH detector. This search results in the observation of 0 and 2 candidates in each of these channels, respectively, while 0.44 and 0.81 background events are expected. The following 90% confidence level upper limits are derived:Br(Z→BcXBr(Z→qq̄Br(Bc+→Jψπ+)

Source-Aware Multidatabase Query Processing, Ee Peng Lim, Yinyan Cao, Roger Hsiang-Li Chiang

Research Collection School Of Computing and Information Systems

We introduce a multidatabase model to represent the information that derives from different local databases. This model, known as Tuple-Source (TS) relational model, accommodates tuples from different local databases by attaching them with their source information in the global relations which are also known as TS-relations. In other words, a source attribute is implicit in every TS-relation. To manipulate the global relations, we have developed the TSSQL query language and implemented a distributed query processor to process such queries. In this paper, we report our distributed query processing architecture and algorithms. Our architecture consists of a query mediator and a …

A Measurement Of Rb Using Mutually Exclusive Tags, R. Barate, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

A measurement of Rb using ve mutually exclusive hemisphere tags has been performed by ALEPH using the full LEP1 statistics. Three tags are designed to select the decay of the Z0 to b quarks, while the remaining two select Z0 decays to c and light quarks, and are used to measure the tagging eciencies. The result, Rb = 0:2159 0:0009(stat) 0:0011(syst), is in agreement with the electroweak theory prediction of 0:21580:0003.

Study Of Muon-Pair Production At Centre-Of-Mass Energies From 20 To 136 Gev With The Aleph Detector, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

The total cross section and the forward-backward asymmetry for the process e+e− → μ+μ−(nγ) are measured in the energy range 20–136 GeV by reconstructing the effective centre-of-mass energy after initial state radiation. The analysis is based on the data recorded with the ALEPH detector at LEP between 1990 and 1995, corresponding to a total integrated luminosity of 143.5 pb−1. Two different approaches are used: in the first one an exclusive selection of events with hard initial state radiation in the energy range 20–88 GeV is directly compared with the Standard Model predictions showing good agreement. In the second one, all …

A Vhdl-93 Hardware Description Browser, Laura C. Debrock, Krishnaprasad Thirunarayan

Kno.e.sis Publications

This paper describes the design and implementation of the VHDL-93 Hardware Description Browser, which is a tool for the intelligent retrieval of information from VHDL designs. The Browser consists of two UNIX processes: a TCL/TK Graphical User Interface and a Prolog search engine. The GUI elicits queries from the user and submits them to the Prolog search engine via a two-way communication pipe. The search engine satisfies queries by traversing a forest of parse trees corresponding to the associated VHDL designs. The results are then sent to the GUI for posting.

Two public-domain tools were used to implement the Browser: …

Investigating The Use Of Kalman Filtering Approaches For Dynamic Origin-Destination Trip Table Estimation, Pushkin Kachroo, Kaan Ozbay, Arvind Narayanan

Electrical & Computer Engineering Faculty Research

This paper studies the applicability of Kalman filtering approaches for network wide traveler origin-destination estimation from link traffic volumes. The paper evaluates the modeling assumptions of the Kalman filters and examines the implications of such assumptions.

Feedback Control Solutions To Network Level User-Equilibrium Real-Time Dynamic Traffic Assignment Problems, Pushkin Kachroo, Kaan Ozbay

Electrical & Computer Engineering Faculty Research

A new method for performing dynamic traffic assignment (DTA) is presented which is applicable in real time, since the solution is based on feedback control. This method employs the design of nonlinear H∞ feedback control systems which is robust to certain class of uncertainties in the system. The solution aims at achieving user equilibrium on alternate routes in a network setting.

A New On-Line Cash Check Scheme, Robert H. Deng, Yongfei Han, Albert B. Jeng, Teow-Hin Ngair

Research Collection School Of Computing and Information Systems

This paper presents a new on-line cash check scheme which guarantees payor anonymity and improves upon existing similar schemes in efficiency and security.

Distributed Query Processing For Structured And Bibliographic Databases, Ee Peng Lim, Ying Lu

Research Collection School Of Computing and Information Systems

To support future digital library systems which draw information from different sources on the internet, we have to provide integrated queries to pre-existing database servers which contain structured, semi-structured and unstructured data. In this paper, we specifically examine the problem of querying both existing structured relational databases and bibliographic databases. By adopting the well-accepted Z39.50 standard protocol to access bibliographic databases in different legacy library systems, we have developed an extended SQL model, known as HarpSQL, to support integrated queries to both SQL databases and bibliographic databases. Using HarpSQL, one can not only query bibliographic databases in an SQL manner, …

Characterizing A Portable Subset Of Behavioral Vhdl-93, Krishnaprasad Thirunarayan, Robert Ewing

Kno.e.sis Publications

Goossens defined a structural operational semantics for a subset of VHDL-87 and proved that the parallelism present in VHDL is benign. We extend this work to include VHDL-93 features such as shared variables and postponed processes that change the underlying semantic model. In the presence of shared variables, nondeterministic execution of VHDL-93 processes destroys the unique meaning property. We identify and characterize a class of portable VHDL-93 descriptions for which unique meaning property can be salvaged. Our specification can serve as a correctness criteria for a VHDL-93 simulator.

The Carnot Heterogeneous Database Project: Implemented Applications, Munindar Singh, Phil Cannata, Michael N. Huhns, Nigel Jacobs, Tomasz Ksiezyk, Kayliang Ong, Amit P. Sheth, Christine Tomlinson, Darrell Woelk

Kno.e.sis Publications

The Carnot project was an ambitious research project in heterogeneous databases. It integrated a variety of techniques to address a wide range of problems in achieving interoperation in heterogeneous environments. Here we describe some of the major implemented applications of this project. These applications concern(a) accessing a legacy scientific database, (b) automating a workflow involving legacy systems, (c) cleaning data, and (d) retrieving semantically appropriate information from structured databases in response to text queries. These applications support scientific decision support, business process management, data integrity enhancement, and analytical decision support, respectively. They demonstrate Carnot‘s capabilities for (a) heterogeneous query processing, …

Cascade Artmap: Integrating Neural Computation And Symbolic Knowledge Processing, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

This paper introduces a hybrid system termed cascade adaptive resonance theory mapping (ARTMAP) that incorporates symbolic knowledge into neural-network learning and recognition. Cascade ARTMAP, a generalization of fuzzy ARTMAP, represents intermediate attributes and rule cascades of rule-based knowledge explicitly and performs multistep inferencing. A rule insertion algorithm translates if-then symbolic rules into cascade ARTMAP architecture. Besides that initializing networks with prior knowledge can improve predictive accuracy and learning efficiency, the inserted symbolic knowledge can be refined and enhanced by the cascade ARTMAP learning algorithm. By preserving symbolic rule form during learning, the rules extracted from cascade ARTMAP can be compared …

Studies Of Qcd In E+E- → Hadrons At Ecm = 130 And 136 Gev, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

Studies of QCD in e+e−→e+e−→ Hadrons at Ecm=Ecm=} 130 and 136 GeV The ALEPH Collaboration An analysis of the properties of hadronic final states produced in electron-positron annihilation at centre-of-mass energies of 130 and 136 GeV is presented. The measurements are based on a data sample of 5.7 pb−1pb−1 collected in November 1995 with the \Aleph detector at LEP. Inclusive charged particle distributions, jet rates and event-shape distributions are measured and the results are compared with the predictions of QCD-based models. From the measured distributions quantities are determined for which the dependence on the centre-of-mass energy can be predicted by …

Inductive Neural Logic Network And The Scm Algorithm, Ah-Hwee Tan, Loo-Nin Teow

Research Collection School Of Computing and Information Systems

Neural Logic Network (NLN) is a class of neural network models that performs both pattern processing and logical inferencing. This article presents a procedure for NLN to learn multi-dimensional mapping of both binary and analog data. The procedure, known as the Supervised Clustering and Matching (SCM) algorithm, provides a means of inferring inductive knowledge from databases. In contrast to gradient descent error correction methods, pattern mapping is learned by an inductive NLN using fast and incremental clustering of input and output patterns. In addition, learning/encoding only takes place when both the input and output match criteria are satisfied in a …

Some Relationships Between Foies And Sigma 1 1 Arity Hierarchies, Guozhu Dong, Limsoon Wong

Kno.e.sis Publications

No abstract provided.

Structural Issues In Active Rule Systems, James Bailey, Guozhu Dong, Kotagiri Ramamohanarao

Kno.e.sis Publications

Active database systems enhance the functionality of traditional databases through the use of active rules or ‘triggers’. There is little consensus, though, on what components should be included in a rule system. In this paper, the expressive power of some simple active database rule systems is examined and the effect of choosing different features studied. Four important parameters of variation are presented, namely the rule language, the external query language, the meta rule language and the pending rule structure. We show that each of these is highly influential in determining the expressiveness of the rule system as a whole, and …

An Error Handling Framework For The Orbwork Workflow Enactment Service Of Meteor, Davasish Worah, Amit P. Sheth, Krzysztof J. Kochut, John A. Miller

Kno.e.sis Publications

Workflow Management Systems (WFMSs) can be used to re-engineer, streamline, automate, and track organizational processes involving humans and automated information systems. However, the state-of-the-art in workflow technology suffers from a number of limitations that prevent it from being widely used in large-scale mission critical applications. Error handling is one such issue. What makes the task of error handling challenging is the need to deal with errors that appear in various components of a complex distributed application execution environment, including various WFMS components, workflow application tasks of different types, and the heterogeneous computing infrastructure.

In this paper, we discuss a top-down …

Managing World Wide Web Publications, Schubert Foo, Ee Peng Lim

Research Collection School Of Computing and Information Systems

The surge of interest in the World Wide Web (WWW), with its potential commercial payoff, has resulted in an explosion of information as organizations join in the fray to publish and do business on the Internet. In addition, Intranet, the private corporate WWW‐based network, has also emerged to provide cost‐effective and efficient groupware and information management solutions for organizations. As a result, the HyperText Markup Language used for constructing WWW documents has become a contender for authoring future office documents. Examines the current practices of WWW publishing and highlights its inadequacies and drawbacks. Demonstrates the need and advantages of using …

Measurement Of The Spectral Functions Of Vector Current Hadronic Tau Decays, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

A measurement of the spectral functions of non-strange τ vector current final states is presented, using 124 358 τ pairs recorded by the ALEPH detector at LEP during the years 1991 to 1994. The spectral functions of the dominant two- and four-pion τ decay channels are compared to published results of e + e - annihilation experiments via isospin rotation. A combined fit of the pion form factor from τ decays and e + e - data is performed using different parametrizations. The mass and the width of the ρ ±(770) and the ρ 0(770) are separately determined in order …

The Topology Dependence Of Charged Particle Multiplicities In Three-Jet Events, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

A study of individual jet and whole-event charged particle multiplicities in three-jet events measured in e + e − annihilation at the Z reveals a significant topology dependence. Mean jet multiplicities are inadequately described by jet energies; interjet angles must also be specified. Quantitative tests suggest that it is necessary to use transversemomentum- like scales to describe the data.