Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Keyword
-
- Query processing (2)
- Associative memory (1)
- Confidence factor (1)
- Enterprise integration (1)
- Exception handling (1)
-
- Exceptions (1)
- Federated database (1)
- Fuzzy ARTMAP rule (1)
- Heteroassociative recall (1)
- Memory management (1)
- Neural network architecture (1)
- Priority scheduling (1)
- Process design (1)
- Pruning (1)
- Real-time database systems (1)
- Schema integration (1)
- Self-organization (1)
- Supervised learning (1)
- Total quality management (1)
- Transaction management (1)
Articles 1 - 25 of 25
Full-Text Articles in Physical Sciences and Mathematics
Measurement Of The Bs0 Lifetime And Production Rate With Ds- ℓ+ Combinations In Z Decays, D. Buskulic, M. Thulasidas
Measurement Of The Bs0 Lifetime And Production Rate With Ds- ℓ+ Combinations In Z Decays, D. Buskulic, M. Thulasidas
Research Collection School Of Computing and Information Systems
A precise determination of the effective Bs0→K+K− lifetime can be used to constrain contributions from physics beyond the Standard Model in the Bs0 meson system. Conventional approaches select B meson decay products that are significantly displaced from the B meson production vertex. As a consequence, B mesons with low decay times are suppressed, introducing a bias to the decay time spectrum which must be corrected. This analysis uses a technique that explicitly avoids a lifetime bias by using a neural network based trigger and event selection. Using 1.0fb−1 of data recorded by the LHCb experiment, the effective Bs0→K+K− lifetime is …
Measurement Of Αs From Scaling Violations In Fragmentation Functions In E+E- Annihilation, D. Buskulic, Manoj Thulasidas
Measurement Of Αs From Scaling Violations In Fragmentation Functions In E+E- Annihilation, D. Buskulic, Manoj Thulasidas
Research Collection School Of Computing and Information Systems
A study of scaling violations in fragmentation functions performed by the ALEPH collaboration at LEP is presented.
Measurements Of The B Baryon Lifetime, D. Buskulic, Manoj Thulasidas
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
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 …
Multiclass Query Scheduling In Real-Time Database Systems, Hwee Hwa Pang, Michael J. Carey, Miron Livny
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. …
Measurement Of The D*± Cross Section In Two Photon Collisions At Lep, D. Buskulic, M. Thulasidas
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
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 …
Test Of The Flavour Independence Of Αs, D. Buskulic, Manoj Thulasidas
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
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.
Myriad: Design And Implementation Of A Federated Database Prototype, Ee Peng Lim, San-Yih Hwang, Jaideep Srivastava, Dave Clements, M. Ganesh
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
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.
Exceptions And Exception Handling In Computerized Information Processes, Diane M. Strong, Steven M. Miller
Exceptions And Exception Handling In Computerized Information Processes, Diane M. Strong, Steven M. Miller
Research Collection School Of Computing and Information Systems
Exceptions, situations that cannot be correctly processed by computer systems, occur frequently in computer-based information processes. Five perspectives on exceptions provide insights into why exceptions occur and how they might be eliminated or more efficiently handled. We investigate these perspectives using an in-depth study of an operating information process that has frequent exceptions. Our results support the use of a total quality management (TQM) approach of eliminating exceptions for some exceptions, in particular, those caused by computer systems that are poor matches to organizational processes. However, some exceptions are explained better by a political system perspective of conflicting goals between …
An Upper Limit For The Τ Neutrino Mass From Τ → 5Π(Π0)Ντ Decays, D. Buskulic, M. Thulasidas
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.
Michel Parameters And Τ Neutrino Helicity From Decay Correlations In Z → Τ+Τ-, D. Buskulic, Manoj Thulasidas
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.
Study Of The Subjet Structure Of Quark And Gluon Jets, D. Buskulic, D., M. Thulasidas
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.
A Type I Hybrid Arq System With Adaptive Code Rates, Robert H. Deng, Michael L. Lin
A Type I Hybrid Arq System With Adaptive Code Rates, Robert H. Deng, Michael L. Lin
Research Collection School Of Computing and Information Systems
Type I hybrid ARQ systems use an error-control code of fixed rate for error-correction in each transmitted packet. In such systems, the code rate must be carefully chosen to match the channel bit error rate (BER) in order to maximize system throughput. Whenever there is a mismatch between code rate and channel BER, the throughput suffers. In this paper, we proposed a type I hybrid ARQ system which automatically adjusts its code rates to match channel BERs. The proposed system is very simple to implement and yet performs significantly better than type I hybrid ARQ systems of fixed code rate
A Study Of D*+ Π- Production In Semileptonic B Decay, D. Buskulic, M. Thulasidas
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 …
Adaptive Resonance Associative Map, Ah-Hwee Tan
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 …
First Measurement Of The Quark-To-Photon Fragmentation Function, D. Buskulic, Manoj Thulasidas
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 …
Multiple Query Optimization With Depth-First Branch-And-Bound And Dynamic Query Ordering, Ee Peng Lim, Ahmet Cosar, Jaideep Srivastava
Multiple Query Optimization With Depth-First Branch-And-Bound And Dynamic Query Ordering, Ee Peng Lim, Ahmet Cosar, Jaideep Srivastava
Research Collection School Of Computing and Information Systems
In certain database applications such as deductive databases, batch query processing, and recursive query processing etc., usually a single query gets transformed into a set of closely related database queries. Also, great benefits can be obtained by executing a group of related queries all together in a single unified multi-plan instead of executing each query separately. In order to achieve this Multiple Query Optimization (MQO) identifies common task(s) (e.g. common subexpressions, joins, etc.) among a set of query plans and creates a single unified plan (multi-plan) which can be executed to obtain the required outputs for all queries at once. …
Object Interactions As First Class Objects: From Design To Implementation, Mahesh Dodani, Benjamin Kok Siew Gan, Lizette Velazquez
Object Interactions As First Class Objects: From Design To Implementation, Mahesh Dodani, Benjamin Kok Siew Gan, Lizette Velazquez
Research Collection School Of Computing and Information Systems
Collaborations between objects make up the dynamic behavior of OO software. These collaborations among objects require careful design and implementation. Treating the interactions as responsibilities that are integrated in the participating objects, results in tight coupling between objects. Tight coupling increases complexity and reduces reusability. Object interactions need to be first class objects from design to implementation. Our research provides a unified approach to model and implement these interactions as first class objects. During analysis and design, they are modeled using DynaSpecs. During implementation, they are coded with a new language construct called Compositions. DynaSpecs and Compositions provide a consistent …
Rule Extraction: From Neural Architecture To Symbolic Representation, Gail A. Carpenter, Ah-Hwee Tan
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, …
Production Of Excited Beauty States In Z Decays, D. Buskulic, Manoj Thulasidas
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.
Inclusive Production Of Neutral Vector Mesons In Hadronic Z Decays, D. Buskulic, Manoj Thulasidas
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 …
Improved Tau Polarisation Measurement, D. Buskulic, M. Thulasidas
Improved Tau Polarisation Measurement, D. Buskulic, M. Thulasidas
Research Collection School Of Computing and Information Systems
Using 22 pb−1 of data collected at LEP in 1992 on the peak of the Z resonance, the ALEPH collaboration has measured the polarisation of the tau leptons decaying intoevv¯,μvv¯evv¯,μvv¯,πν, ρν and a1 ν from their individual decay product distributions. The measurement of the tau polarisation as a function of the production polar angle yields the two parametersN τ andN e, where, in terms of the axial and vector couplingsg Al andg Vl,N l=2g Vl gAl/(g 2Vl+g2Al). This analysis follows to a large extent the methods devised for the 1990 and 1991 data but with improvements which bring a better …