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Study Of Muon-Pair Production At Centre-Of-Mass Energies From 20 To 136 Gev With The Aleph Detector, R. Barate, M. Thulasidas May 1997

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 …

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A Measurement Of Rb Using Mutually Exclusive Tags, R. Barate, Manoj Thulasidas May 1997

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.

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A Measurement Of Rb Using A Lifetime-Mass Tag, R. Barate, Manoj Thulasidas May 1997

A Measurement Of Rb Using A Lifetime-Mass Tag, R. Barate, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

ALEPH's published measurement of Rb = Γ(Ζ → bb̄)/Γ(Ζ → hadrons) using a lifetime tag is updated using the full LEP 1 data sample. Considerable effort has been devoted to understanding systematic effects. Charm background is better controlled by combining the lifetime tag with a tag based on the b/c hadron mass difference. Furthermore, the algorithm used to reconstruct the event primary vertex is designed so as to reduce correlations between the two hemispheres of an event. The value of Rb is measured to be 0.2167 ± 0.0011 (stat) ± 0.0013 (syst).

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Source-Aware Multidatabase Query Processing, Ee Peng Lim, Yinyan Cao, Roger Hsiang-Li Chiang May 1997

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 …

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A New On-Line Cash Check Scheme, Robert H. Deng, Yongfei Han, Albert B. Jeng, Teow-Hin Ngair Apr 1997

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.

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Distributed Query Processing For Structured And Bibliographic Databases, Ee Peng Lim, Ying Lu Apr 1997

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, …

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Making Sense Of The Asian Success Story: An Integrative Framework, Chow Hou Wee, Gilbert Tan Mar 1997

Making Sense Of The Asian Success Story: An Integrative Framework, Chow Hou Wee, Gilbert Tan

Research Collection Lee Kong Chian School Of Business

The article focuses on Asian countries that have experienced economic growth over the past 50 years including Hong Kong, China; Japan; Singapore; South Korea and Taiwan. With the exception of Hong Kong, the economic success of the Asian countries has been attributed to the interventionist framework. Export-orientation is one strategy that is most associated with the success of the five Asian countries. The export-oriented strategy helped the five Asian countries in many ways. The ensuring growth of employment enabled the country to save and accumulate capital for reinvestment. The export-oriented strategy also positively affects the competitive advantages of the country. …

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Cascade Artmap: Integrating Neural Computation And Symbolic Knowledge Processing, Ah-Hwee Tan Mar 1997

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 …

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A System For Query Comprehension, Hock Chuan Chan, Kwok Kee Wei, Keng Siau Mar 1997

A System For Query Comprehension, Hock Chuan Chan, Kwok Kee Wei, Keng Siau

Research Collection School Of Computing and Information Systems

A major difficulty of query writing is that users do not fully understand queries. A system providing feedback is proposed so as to enable users to better understand their queries. It is a multi-functional rule-based system. In addition to providing an English translation for the query, it pin-points syntax errors, and suggests possible solutions. It also finds likely semantic errors, and provides possible solutions. The system was implemented for a query language based on the entity relationship model. It is expected to lead to better user performance. Empirical testing showed significant improvement in user performance with the feedback system. The …

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Inductive Neural Logic Network And The Scm Algorithm, Ah-Hwee Tan, Loo-Nin Teow Feb 1997

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 …

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Studies Of Qcd In E+E- → Hadrons At Ecm = 130 And 136 Gev, D. Buskulic, M. Thulasidas Feb 1997

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 …

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Transverse Momentum Correlations In Hadronic Z Decays, D. Buskulic, M. Thulasidas Jan 1997

Transverse Momentum Correlations In Hadronic Z Decays, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

Using data obtained with the ALEPH detector at the Z resonance, a measure based on transverse momentum is shown to exhibit a correlation between the two halves of a hadronic event which cannot be explained by energy-momentum conservation, flavour conservation, the imposition of an event axis or imperfect event reconstruction. Two possible interpretations based on existing Monte Carlo models are examined: a) ARIADNE, with the correlation forming early in the parton shower and with the transition from partons to hadrons playing only a minor part; b) JETSET, with the correlation forming at the fragmentation stage. A correlation technique based on …

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A Study Of Τ Decays Involving Η And Ω Mesons, D. Buskulic, M. Thulasidas Jan 1997

A Study Of Τ Decays Involving Η And Ω Mesons, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

The 132 pbt - 1 of data collected by ALEPH from 1991 to 1994 have been used to analyze η and ω production in τ decays. The following branching fractions have been measured: B(τ−→ντωh−)=(1.91±0.07±0.06)×10−2,B(τ−→ντωh−)=(1.91±0.07±0.06)×10−2, B(τ−→ντωh−π0)=(4.3±0.6±0.5)×10−3,B(τ−→ντωh−π0)=(4.3±0.6±0.5)×10−3, B(τ−→ντηK−)=(2.9+1.3−1.2±0.7)×10−4,B(τ−→ντηK−)=(2.9−1.2+1.3±0.7)×10−4, B(τ−→ντηh−π0)=(1.8±0.4±0.2)×10−3B(τ−→ντηh−π0)=(1.8±0.4±0.2)×10−3 and the 95% C.L. limit B(τ− → ντηπt -) t - 4 has been obtained. The ωπt- and ηπt -π0 rates and dynamics are found in agreement with the predictions made from e+e∼ - annihilation data with the help of isospin invariance (CVC).

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The Topology Dependence Of Charged Particle Multiplicities In Three-Jet Events, R. Barate, M. Thulasidas Jan 1997

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.

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Managing World Wide Web Publications, Schubert Foo, Ee Peng Lim Jan 1997

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 …

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Integrated Queries To Existing Bibliographic And Structured Databases, Ee Peng Lim, Ying Lu Jan 1997

Integrated Queries To Existing Bibliographic And Structured Databases, Ee Peng Lim, Ying Lu

Research Collection School Of Computing and Information Systems

It is widely accepted that future digital library applications have to be built upon different kinds of database servers to draw upon different forms of data, including bibliographic, text, multimedia, and structured data. In this paper, the problem of integrating existing public bibliographic databases and structured databases which reside at different locations in the network is addressed. Although bibliographic data is semistructured, its attribute set is often determined by an international standard known as MARC. To unify bibliographic and structured data, the well-known SQL was extended to model bibliographic related attributes and queries. In particular, a new data type was …

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Measurement Of The Spectral Functions Of Vector Current Hadronic Tau Decays, R. Barate, M. Thulasidas Jan 1997

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 …

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Measurement Of The Τ Lepton Lifetime With The Three-Dimensional Impact Parameter Method, R. Barate, M. Thulasidas Jan 1997

Measurement Of The Τ Lepton Lifetime With The Three-Dimensional Impact Parameter Method, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

A new method is presented for the measurement of the mean lepton lifetime using events in which are pair-produced and both's decay to hadrons.

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Production Of Orbitally Excited Charm Mesons In Semileptonic B Decays, D. Buskulic, M. Thulasidas Jan 1997

Production Of Orbitally Excited Charm Mesons In Semileptonic B Decays, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

A sample of 3.6 million hadronic Z decays recorded between 1991 and 1995 with the ALEPH detector at LEP is used to investigate semileptonic decays of B mesons into final states involving orbitally excited charm mesons. Topological vertex criteria are used to search for decays involving narrow D** states as well as wide D** resonances and non-resonant D(*)π final states. The sum of the branching ratios for these processes is measured to be ${⤪ Br}({⩈erline {⤪ B}}⌝ghtarrow {⤪ D}≪ ⫑l^{-}{⩈erline v}) + {⤪ Br}({⩈erline {⤪ B}}⌝ghtarrow {⤪ D}^{⇒t}≪ ⫑l^{-}{⩈erline v})↦op =(2.26 pm 0.29({⤪ stat}) pm 0.33({⤪ syst}))%,$which accounts for a …

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Improved Measurement Of The Bd0 -B̄D0 Oscillation Frequency, D. Buskulic, M. Thulasidas Jan 1997

Improved Measurement Of The Bd0 -B̄D0 Oscillation Frequency, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

The time dependence of B0 d {B 0 d oscillations is measured by the ALEPH experiment at LEP, using three techniques, two of which are updates of previous measurements. In all cases the charge of the decaying b quark and its decay time are measured in one hemisphere of the event; the quark charge at production is tagged mainly using the opposite hemisphere. The first method uses the charge correlation between a D and a lepton in the opposite hemisphere; if no lepton is present, the produced quark charge is determined from the hemisphere charges. In the second method, the …

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A Hypermedia Database To Manage World-Wide-Web Documents, Schubert Shou Boon Foo, Ee Peng Lim Jan 1997

A Hypermedia Database To Manage World-Wide-Web Documents, Schubert Shou Boon 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 organisations join in to publish and do business on the Internet. A related development, Intranet, which basically uses the same technology to build private corporate WWW-based networks, has emerged to provide cost-effective and efficient groupware and information management solutions for organisations. As a result, the Hyper Text Markup Language (HTML), used for constructing WWW documents, has become a contender for authoring future office documents. With this scenario, this study examines WWW practices and highlights the inadequacy and drawbacks of …

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Low-Degree Graph Partitioning Via Local Search With Applications To Constraint Satisfaction, Max Cut, And Coloring, Magnus M. Halldorsson, Hoong Chuin Lau Jan 1997

Low-Degree Graph Partitioning Via Local Search With Applications To Constraint Satisfaction, Max Cut, And Coloring, Magnus M. Halldorsson, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

We present practical algorithms for constructing partitions of graphs into a fixed number of vertex-disjoint subgraphs that satisfy particular degree constraints. We use this in particular to find k-cuts of graphs of maximum degree ∆ that cut at least a k - 1/k (1 + 1/2∆+k-1 ) fraction of the edges, improving previous bounds known. The partitions also apply to constraint networks, for which we give a tight analysis of natural local search heuristics for the maximum constraint satisfaction problem. These partitions also imply efficient approximations for several problems on weighted bounded-degree graphs. In particular, we improve the best performance …

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Export Database Derivation Approach For Supporting Object-Oriented Wrapper Queries, Ee Peng Lim, Hon-Kuan Lee Dec 1996

Export Database Derivation Approach For Supporting Object-Oriented Wrapper Queries, Ee Peng Lim, Hon-Kuan Lee

Research Collection School Of Computing and Information Systems

Wrappers export the schema and data of existing heterogeneous databases and support queries on them. In the context of cooperative information systems, we present a flexible approach to specify the derivation of object-oriented (OO) export databases from local relational databases. Our export database derivation consists of a set of extent derivation structures (EDS) which defines the extent and deep extent of export classes. Having well-defined semantics, the EDS can be readily used in transforming wrapper queries to local queries. Based on the EDS, we developed a wrapper query evaluation strategy which handles OO queries on the export databases. The strategy …

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Four-Fermion Production In E+E- Collisions At Centre-Of-Mass Energies Of 130 And 136 Gev, D. Buskulic, Manoj Thulasidas Nov 1996

Four-Fermion Production In E+E- Collisions At Centre-Of-Mass Energies Of 130 And 136 Gev, D. Buskulic, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

Four-fermion events have been selected in a data sample of 5.8 pb−1 collected with the aleph detector at centre-of-mass energies of 130 and 136 GeV. The final states ℓ+ℓ−qq, ℓ+ℓ−ℓ+ℓ−, ννqq, and ννℓ+ℓ− have been examined. Five events are observed in the data, in agreement with the Standard Model predictions of 6.67±0.38 events from four-fermion processes and 0.14−0.05+0.19 from background processes.

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An Evidential Reasoning Approach To Attribute Value Conflict Resolution In Database Integration, Ee Peng Lim, Jaideep Srivastava, Shashi Shekhar Oct 1996

An Evidential Reasoning Approach To Attribute Value Conflict Resolution In Database Integration, Ee Peng Lim, Jaideep Srivastava, Shashi Shekhar

Research Collection School Of Computing and Information Systems

Resolving domain incompatibility among independently developed databases often involves uncertain information. DeMichiel [1] showed that uncertain information can be generated by the mapping of conflicting attributes to a common domain, based on some domain knowledge. In this paper, we show that uncertain information can also arise when the database integration process requires information not directly represented in the component databases, but can be obtained through some summary of data. We therefore propose an extended relational model based on Dempster-Shafer theory of evidence [2] to incorporate such uncertain knowledge about the source databases. The extended relation uses evidence sets to represent …

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Observation Of Charmless Hadronic B Decays, Buskulic, D.; Et Al., M. Thulasidas Sep 1996

Observation Of Charmless Hadronic B Decays, Buskulic, D.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

No abstract provided.

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Strange B Baryon Production And Lifetime In Z Decays, D. Buskulic, M. Thulasidas Sep 1996

Strange B Baryon Production And Lifetime In Z Decays, D. Buskulic, M. Thulasidas

Research Collection School Of Computing and Information Systems

In a data sample of approximately four million hadronic Z decays recorded with the ALEPH detector from 1990 to 1995, a search for the strange b baryon Ξb is performed with a study of Ξ-lepton correlations. Forty-four events with same sign Ξ−ℓ− combinations are found whereas 8.4 are expected based on the rate of opposite sign Ξ−ℓ+ combinations. This significant excess is interpreted as evidence for Ξb semileptonic decays. The measured product branching ratio is Br(b → Ξb) × Br(Ξb→ XcXℓ−νℓ) × Br(Xc→ Ξ−X′) = (5.4±1.1(stat) ± 0.8(syst)) × 10−4 per lepton species, averaged over electrons and muons, with Xc …

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An On-The-Fly Decoding Technique For Reed-Solomon Codes, Yuan Xing Lee, Robert H. Deng, Eng Hean Koh Sep 1996

An On-The-Fly Decoding Technique For Reed-Solomon Codes, Yuan Xing Lee, Robert H. Deng, Eng Hean Koh

Research Collection School Of Computing and Information Systems

An on-the-fly error correction technique for double-byte-error-correction (DBEC) and triple-byte-error-detection (TBED) Reed-Solomon (RS) codes is presented in this paper. This new algorithm finds number of byte-errors (single byte-error, double-byte errors, and triple-byte errors) by simply testing the values of a few syndrome functions, and locates and corrects the byte-errors directly without using the standard iterative algorithms for finding the error location polynomial. More importantly, it neither suffers from malfunctions incurred in Deng-Costello algorithm (1987), nor requires syndrome re-calculation as in Koksal-Yucel's modification (1992). It is also much more simpler and faster than the original Deng-Costello algorithm. It has found applications …

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Resource-Constrained Project Scheduling: A Survey Of Recent Developments, Willy Herroelen, Erik Demeulemeester, Bert De Reyck Sep 1996

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

Research Collection Lee Kong Chian School Of Business

Resource-constrained project scheduling involves the scheduling of project activities subject to precedence and resource constraints in order to meet the objective(s) in the best possible way. The area covers a wide variety of problem types. The objective of this paper is to provide a survey of what we believe are the important recent developments in the area. Our main focus will be on the recent progress made in and the encouraging computational experience gained with the use of optimal solution procedures for the basic resource-constrained project scheduling problem (RCPSP) and important extensions. We illustrate how the branching rules, dominance and …

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Measurement Of The B Forward-Backward Asymmetry And Mixing Using High-P⊥ Leptons, Buskulic, D., M. Thulasidas Sep 1996

Measurement Of The B Forward-Backward Asymmetry And Mixing Using High-P⊥ Leptons, Buskulic, D., M. Thulasidas

Research Collection School Of Computing and Information Systems

The B0 - B̄0 average mixing parameter χ and b forward-backward asymmetry AFB0(b) are measured from a sample of about 4 200 000 Z → qq̄ events recorded with the ALEPH detector at LEP in the years 1990–1995. High transverse momentum electrons and muons produced in b semileptonic decays provide the tag of the quark flavour and of its charge.The average mixing parameter and the pole b asymmetry are measured to be χ = 0.1246 ± 0.0051stat ± 0.0052syst, AFB0(b) = 0.1008 ± 0.0043stat ± 0.0028syst. The value of sin2θweff = 0.23198 ± 0.00092 is extracted from the asymmetry measurement.

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