Physical Sciences and Mathematics Commons^™

Measurements Of The B Baryon Lifetime, D. Buskulic, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

The average lifetime of b-flavoured baryons measured with the OPAL detector is updated to include data collected between 1990 and 1994 at LEP. Bottom-flavoured baryons that decay semileptonically and produce aΛ baryon are identified through the correlation of the baryon number of theΛ and the electric charge of the lepton. To measure the lifetime, the decay point of the b baryon is estimated by theΛ-lepton vertex, and the observed distribution of decay lengths is fitted simultaneously in 874 right-sign and 384 wrong-sign combinations. In a separate method, the impact parameter distribution of the leptons is fitted in a subset of …

Measurement Of The Effective B Quark Fragmentation Function At The Z Resonance, Buskulic, D.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

Using a sample of about 1.46 million hadronic Z decays collected between 1991 and 1993 with the ALEPH detector at LEP, the energy distribution of the B0 and B± mesons produced at the Z resonance is measured by reconstructing semileptonic decays B → ℓνℓD(X) or B→ ℓνℓD∗+(X). The charmed mesons are reconstructed through the decay modes D0 → K−π+, D0 → K−π+π−π+, D+ → K−π+π+ and D∗+→ D0π+. The neutrino energy is estimated from the missing energy in the lepton hemisphere. Accounting for B∗ and B∗∗ production, the shape of the scaled energy distribution xE(b) for mesons containing a b …

Power Systems Marginal Cost Curve And Its Applications, Shaojun Wang, S. M. Shahidehpour, Nian-De Xiang

Kno.e.sis Publications

This paper presents a forward recursive procedure to calculate the expected system marginal cost curve (EMC). The EMC formulation allows for multi-state and multi-block dispatch of generating units and is used to determine the optimal energy of pumped-storage units. A new approach is developed to compute the first and second derivatives of the expected generation energy of a thermal unit with respect to the capacity of all thermal units in the system. The salient feature of the proposed approach is that it applies to hydro-thermal systems with multiple limited-energy hydro units.

Measurement Of The D*± Cross Section In Two Photon Collisions At Lep, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

The inclusive production of D∗± mesons in photon-photon collisions has been measured by the Aleph experiment at LEP with a beam energy of 45 GeV. The D∗+ are detected in their decay to D0π+ with the D0 observed in three separate decay modes: (1) K−π+, (2) K−π+π0 and (3) K−π+π−π+, and analagously for the D∗− modes. A total of 33 events was observed from an integrated luminosity of 73 pb−1 which corresponds to a cross section for Σ(e+e−→ e+e−D∗±X) of 155 ± 33 ± 21 pb. This result is compatible with both the direct production γγ → cc in the …

Limit On B0s Oscillation Using A Jet Charge Method, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

A lower limit is set on the Bs0 meson oscillation parameter Δms using data collected from 1991 to 1994 by the ALEPH detector. Events with a high transverse momentum lepton and a reconstructed secondary vertex are used. The high transverse momentum leptons are produced mainly by b hadron decays, and the sign of the lepton indicates the particle/antiparticle final state in decays of neutral B mesons. The initial state is determined by a jet charge technique using both sides of the event. A maximum likelihood method is used to set a lower limit of Δms. The 95% confidence level lower …

Multiclass Query Scheduling In Real-Time Database Systems, Hwee Hwa Pang, Michael J. Carey, Miron Livny

Research Collection School Of Computing and Information Systems

In recent years, a demand for real-time systems that can manipulate large amounts of shared data has led to the emergence of real-time database systems (RTDBS) as a research area. This paper focuses on the problem of scheduling queries in RTDBSs. We introduce and evaluate a new algorithm called Priority Adaptation Query Resource Scheduling (PAQRS) for handling both single class and multiclass query workloads. The performance objective of the algorithm is to minimize the number of missed deadlines, while at the same time ensuring that any deadline misses are scattered across the different classes according to an administratively-defined miss distribution. …

Predicting Conserved Water-Mediated Interactions In Protein Active Sites, Michael L. Raymer, Sridhar Venkataraman, William F. Punch, Erik D. Goodman, Brenda Kuhn

Kno.e.sis Publications

No abstract provided.

Test Of The Flavour Independence Of Αs, D. Buskulic, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

Using about 950 000 hadronic events collected during 1991 and 1992 with the ALEPH detector, the ratios r b = bs=udsc s and r uds = uds s =cbs have been measured in order to test the avour independence of the strong coupling constant s . The analysis is based on event{shape variables using the full hadronic sample, two b-quark samples enriched by lepton tagging and lifetime tagging, and a light-quark sample enriched by lifetime antitagging. The combined results are r b = 1:002 0:023 and r uds = 0:971 0:023.

The Forward-Backward Asymmetry For Charm Quarks At The Z Pole, D. Buskulic, 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.

Visual Pattern Recognition Using Neural Networks, Jenlong Moh

Dissertations

Neural networks have been widely studied in a number of fields, such as neural architectures, neurobiology, statistics of neural network and pattern classification. In the field of pattern classification, neural network models are applied on numerous applications, for instance, character recognition, speech recognition, and object recognition. Among these, character recognition is commonly used to illustrate the feature and classification characteristics of neural networks.

In this dissertation, the theoretical foundations of artificial neural networks are first reviewed and existing neural models are studied. The Adaptive Resonance Theory (ART) model is improved to achieve more reasonable classification results. Experiments in applying the …

A Meta-Interpreter For Circuit-Extraction, Krishnaprasad Thirunarayan

Kno.e.sis Publications

The design of a VLSI circuit consists of a description of the circuit in terms of its components and subcomponents, at various levels of detail. To verify that the layout of a VLSI circuit conforms to its design, one needs to work backwards from the lowest-level description of the circuit and recognize the higher-level components it constitutes. This paper is concerned with the application of logic programming techniques in the formal verification of the structural correctness of the VLSI circuit layouts. In particular, we review Michael Dukes' Generalized Extraction System (1990) that compiles design descriptions into a set of extraction …

The Effect Of Domain Knowledge On Elementary School Children's Search Behavior On An Information Retrieval System: The Science Library Catalog, Sandra Hirsh

Faculty Publications

Few information retrieval systems are designed with children’s special needs and capabilities in mind. We need to learn more about children’s information-seeking behavior in order to provide them with information-based tools which support exploratory learning. This dissertation examines children’s search behavior on a hypertext-based automated library catalog designed for elementary school children. The focus of this research is on the effect of domain knowledge on children’s search performance, search behavior, and learning as they look for science books on this system. Reseaxch has shown that level of domain knowledge in~luences the way people search for information. Data was collected through …

Myriad: Design And Implementation Of A Federated Database Prototype, Ee Peng Lim, San-Yih Hwang, Jaideep Srivastava, Dave Clements, M. Ganesh

Research Collection School Of Computing and Information Systems

A key problem in providing enterprise-wide information is the integration of databases that have been independently developed. An important requirement is to accommodate heterogeneity and maintain the autonomy of component databases. Myriad is a federated database prototype developed at the University of Minnesota, to provide a testbed for investigating alternatives in architecture and algorithms for database integration, query processing and optimization, and concurrency control and recovery. The system incorporates our group's research results in these areas. This paper describes our experiences in the design and implementation of Myriad, and in the project management. Special emphasis is given to discussing design …

Search For Supersymmetric Particles With R-Parity Violation In Z Decays, D. Buskulic, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

Searches for supersymmetric particles produced in e+e− interactions at the Z peak have been performed under the assumptions that R-parity is not conserved, that the dominant R-parity violating coupling involves only leptonic fields, and that the lifetime of the lightest supersymmetric particle can be neglected. In a data sample collected by the ALEPH detector at LEP up to 1993, and corresponding to almost two million hadronic Z decays, no signal was observed. As a result, supersymmetric particle masses and couplings are at least as well constrained as under the usual assumption of R-parity conservation.

An Upper Limit For The Τ Neutrino Mass From Τ → 5Π(Π0)Ντ Decays, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

From a sample of 152,000 τ decays collected by the ALEPH detector at LEP an upper limit of 24 MeV at 95% CL on the τ neutrino mass has been determined. The limit is obtained using a two dimensional likelihood fit of the visible energy and the invariant mass distribution of 25 τ → 5π(π0)ντ events.

Knowledge Acquisition And Structuring By Multiple Experts In A Group Support Systems Environment, Bernard Lee Lewis

Engineering Management & Systems Engineering Theses & Dissertations

This study addresses the impact of Group Decision Support Systems (GDSS) on expert system development by multiple Domain Experts. Current approaches to building expert systems rely heavily on knowledge acquisition and prototyping by a Knowledge Engineer working directly with the Domain Expert. Although the complexity of knowledge domains and new organizational approaches demand the involvement of multiple experts, standard procedures limit the ability of the Knowledge Engineer to work with more than one expert at a time.

Group Decision Support Systems offer a networked computerized environment for group work activities, in which multiple experts may express their ideas concurrently and …

1.4, Yolanda Jones

E-lert

No abstract provided.

Study Of The Subjet Structure Of Quark And Gluon Jets, D. Buskulic, D., M. Thulasidas

Research Collection School Of Computing and Information Systems

Measurements of the subjet structure of quark and gluon jets in hadronic Z decays are presented. The analysis is based on one million hadronic events recorded by the Aleph detector. Roughly symmetric three-jet events are selected with a coarse jet-resolution cut-off, y1. Gluon jets are identified with a purity of 94.6% in those events where evidence of long-lived heavy-flavour hadrons in the other two jets is found. The jets are then analyzed using a smaller cut-off y0 (< y1) so that subjets are resolved. The properties of the jets (subjet multiplicities (Nq), (Ng) and rates Rng(q) for n = 1, 2, 3, 4) are determined and are found to be in good agreement with the expectations of perturbative QCD as long as the subjet resolution parameter y0 is sufficiently large to keep non-perturbative effects small. In particular, the ratio , which to leading order in QCD is given by the ratio of colour factors , is measured to be 1.96 ± 0.15 for y0 = 2 · 10−3, but falls to 1.29 ± 0.03 for y0 = 1.6 · 10−5.

Michel Parameters And Τ Neutrino Helicity From Decay Correlations In Z → Τ+Τ-, D. Buskulic, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

No abstract provided.

1.3, Yolanda Jones

E-lert

No abstract provided.

A Study Of D*+ Π- Production In Semileptonic B Decay, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

In a sample of 1.5 million hadronic decays of the Z collected by the ALEPH detector, a search is carried out for the decays B→ D10(2420)l−νX and B→ D2∗0(2460)l−νX. The product branching ratio for D10 production is measured to be Br(b →B) × Br(B→ D10l−νX) × Br(D10→ D∗+π−) = (2.04 ± 0.58stat± 0.34syst) × 10−3, and a 95% confidence level limit of Br(b →B) × Br(B→ D2∗0l−νX) × Br(D2∗0→ D∗+π−) ≤ 0.81 × 10−3 is obtained for D2∗0 production.A topological search sensitive to the processes above, but also to wide resonances that decay to D∗+π− and to non-resonant D∗+π− production …

1.2, Yolanda Jones

E-lert

No abstract provided.

Book Review: Reasoning Agents In A Dynamic World: The Frame Problem. Kenneth M. Ford And Patrick J. Hayes, Eds.,, Jozsef A. Toth

Jozsef A Toth Ph.D.

No abstract provided.

Nonrecursive Incremental Evaluation Of Datalog Queries, Guozhu Dong, Jianwen Su, Rodney Topor

Kno.e.sis Publications

We consider the problem of repeatedly evaluating the same (computationally expensive) query to a database that is being updated between successive query requests. In this situation, it should be possible to use the difference between successive database states and the answer to the query in one state to reduce the cost of evaluating the query in the next state. We use nonrecursive Datalog (which are unions of conjunctive queries) to compute the differences, and call this process “incremental query evaluation using conjunctive queries”. After formalizing the notion of incremental query evaluation using conjunctive queries, we give an algorithm that constructs, …

Liability Issues In The Development Of Electronic Chart Display Information Systems, Daniel R. Martin

Marine Affairs Theses and Major Papers

The Electronic Chart Display Information System (ECDIS) is a new and evolving aid to navigation. Proponents claim ECDIS will help navigators to synthesize previously disparate information and result in safer navigation. The technology to implement ECDIS already exists; the major hurdle the maritime community faces is the legal uncertainties associated with ECDIS. This paper investigates the potential legal impact ECDIS would have on the government, shipowners, mariners, and manufacturers, and evaluates current international efforts to promote ECDIS. Through a detailed analysis of admiralty and aeronautical case history, it is evident that; 1) generation of electronic nautical charts can post a …

Rule Extraction: From Neural Architecture To Symbolic Representation, Gail A. Carpenter, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

This paper shows how knowledge, in the form of fuzzy rules, can be derived from a supervised learning neural network called fuzzy ARTMAP. Rule extraction proceeds in two stages: pruning, which simplifies the network structure by removing excessive recognition categories and weights; and quantization of continuous learned weights, which allows the final system state to be translated into a usable set of descriptive rules. Three benchmark studies illustrate the rule extraction methods: (1) Pima Indian diabetes diagnosis, (2) mushroom classification and (3) DNA promoter recognition. Fuzzy ARTMAP and ART-EMAP are compared with the ADAP algorithm, the k nearest neighbor system, …

Adaptive Resonance Associative Map, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

This article introduces a neural architecture termed Adaptive Resonance Associative Map (ARAM) that extends unsupervised Adaptive Resonance Theory (ART) systems for rapid, yet stable, heteroassociative learning. ARAM can be visualized as two overlapping ART networks sharing a single category field. Although ARAM is simpler in architecture than another class of supervised ART models known as ARTMAP, it produces classification performance equivalent to that of ARTMAP. As ARAM network structure and operations are symmetrical, associative recall can be performed in both directions. With maximal vigilance settings, ARAM encodes pattern pairs explicitly as cognitive chunks and thus guarantees perfect storage and recall …

Production Of Excited Beauty States In Z Decays, D. Buskulic, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

A data sample of about 3.0 million hadronic Z decays collected by the ALEPH experiment at LEP in the years 1991 through 1994, is used to make an inclusive selection of B hadron events.

First Measurement Of The Quark-To-Photon Fragmentation Function, D. Buskulic, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

Earlier measurements at LEP of isolated hard photons in hadronic Z decays, attributed to radiation from primary quark pairs, have been extended in the ALEPH experiment to include hard photon production inside hadron jets. Events are selected where all particles combine democratically to form hadron jets, one of which contains a photon with a fractional energy z 0:7. After statistical subtraction of non-prompt photons, the quark-to-photon fragmentation function, D(z), is extracted directly from the measured 2-jet rate. By taking into account the perturbative contributions to D(z) obtained from an O(S ) QCD calculation, the unknown non-perturbative component of D(z) is …

Inclusive Production Of Neutral Vector Mesons In Hadronic Z Decays, D. Buskulic, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

Data on the inclusive production of the neutral vector mesonsρ 0(770),ω(782), K*0(892), andφ(1020) in hadronic Z decays recorded with the ALEPH detector at LEP are presented and compared to Monte Carlo model predictions. Bose-Einstein effects are found to be important in extracting a reliable value for theρ 0 production rate. An averageρ 0 multiplicity of 1.45±0.21 per event is obtained. Theω is detected via its three pion decay modeω→π + π − π 0 and has a total rate of 1.07±0.14 per event. The multiplicity of the K*0 is 0.83±0.09, whilst that of theφ is 0.122±0.009, both measured using their …