Programming Languages and Compilers Commons^™

Parametric Polymorphism In The Simple Language, Soumaia Ahmed Al Ayyat

Archived Theses and Dissertations

No abstract provided.

Monitoring The Stability Of The Aleph Vertex Detector, G. Sguazzoni, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

The ALEPH Silicon Vertex Detector features an optical fibre laser system to monitor its mechanical stability. The operating principle and the general performance of the laser system are described. The experience obtained during 1997 and 1998 operations confirms the important role that such a system can have with respect to the detector alignment requirements. In particular, the laser system has been used to monitor short-term temperature-related effects and long-term movements. These results and a description of the laser-based alignment correction applied to the 1998 data are presented.

Determination Of The Lep Centre-Of-Mass Energy From Zγ Events, R. Barate, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

A study of events with photons and missing energy has been performed with the data sample obtained with the ALEPH detector at centre-of-mass energies from 161 to 184 GeV, corresponding to a total integrated luminosity of about 80 pb−1. The measured distributions are in agreement with Standard Model predictions, leading to constraints on WWγ gauge coupling parameters ∆κγ and λγ. The results from the fit to the cross sections and to the energy and angular distributions of the photons are: ∆κγ = 0.05+1.15 −1.10(stat)±0.25(syst) λγ = −0.05+1.55 −1.45(stat)±0.30(syst).

Search For Invisible Higgs Boson Decays In E+E- Collisions At Centre-Of-Mass Energies Up To 184 Gev, R. Barate, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

In a data sample of 78.3 pb−1 collected in 1996 and 1997 by the ALEPH detector at centre-of-mass energies from 161 to 184 GeV, invisible decays of a Higgs boson have been searched for in the reaction e+e− → hZ, where the Z can decay into e+e−, µ+µ− or q¯q. No evidence for a signal is found and limits on the production cross section are derived as a function of the Higgs boson mass. These results are combined with those obtained in an update of the analyses of the ALEPH data taken at LEP 1. For a production cross section …

A Study Of Single W Production In E+E- Collisions At √S = 161-183 Gev, R. Barate, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

Single W production is studied in the data recorded with the ALEPH detector at LEP at centre-of-mass energies between 161 and 183 GeV. The cross section is measured to be σw = 0.41 ± 0.17(stat.) ± 0.04(syst.) pb at 183 GeV, consistent with the Standard Model expectation. Limits on non-standard WWγ couplings are deduced as -1.6 γ γ = 0) and -1.6 γ γ = 1) at 95% C.L. A search for effectively invisible decays of the W boson in W pair production is performed, leading to an upper limit on the branching ratio of 1.3% (Γinv = 27 MeV) …

Measurement Of W-Pair Production In E+E- Collisions At 183 Gev, R. Barate, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

The production of W+W− pairs is analysed in a data sample collected by ALEPH at a mean centre-of-mass energy of 182.7 GeV, corresponding to an integrated luminosity of 57 pb−1 . Cross sections are given for different topologies of W decays into leptons or hadrons. Under Standard Model assumptions for the W-pair production and decay, the W-pair cross section is measured to be 15.57 ± 0.62(stat.) ± 0.29(syst.) pb. Using also the W-pair data samples collected by ALEPH at lower centre-of-mass energies, the decay branching ratio of the W boson into hadrons is measured to be B(W → hadrons) = …

Measurement Of The Hadronic Photon Structure Function At Lep 1 For 〈Q2〉 Values Between 9.9 And 284 Gev2, Barate, R.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

Inclusive γ∗γ interactions to hadronic final states where one scattered electron or positron is detected in the electromagnetic calorimeters have been studied in the LEP 1 data taken by ALEPH from 1991 to 1995. The event sample has been used to measure the hadronic structure function of the photon F2γ in three bins with 〈Q2〉 of 9.9, 20.7 and 284 GeV2.

Measurement Of The W Mass In E+E- Collisions At 183 Gev, Barate, R.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

The mass of the W boson is obtained from reconstructed invariant mass distributions in W-pair events. The sample of W pairs is selected from 57 pb−1 collected with the ALEPH detector in 1997 at a centre-of-mass energy of 183 GeV.

Improving Performance On Incremental Compilation Of Java Bytecodes, Tarique Kazi

Honors Capstone Projects and Theses

No abstract provided.

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.

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.

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

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

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.

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 …

Definitional Interpreters For Higher-Order Programming Languages, John C. Reynolds

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

Abstract. Higher-order programming languages (i.e., languages in which procedures or labels can occur as values) are usually defined by interpreters that are themselves written in a programming language based on the lambda calculus (i.e., an applicative language such as pure LISP). Examples include McCarthy’s definition of LISP, Landin’s SECD machine, the Vienna definition of PL/I, Reynolds ’ definitions of GEDANKEN, and recent unpublished work by L. Morris and C. Wadsworth. Such definitions can be classified according to whether the interpreter contains higher-order functions, and whether the order of application (i.e., call by value versus call by name) in the defined …

Towards A Java Environment For Spmd Programming, Bryan Carpenter, Guansong Zhang, Geoffrey C. Fox, Xiaoming Li

Northeast Parallel Architecture Center

As a relatively straightforward object-oriented language, Java is a plausible basis for a scientific parallel programming language. We outline a conservative set of language extensions to support this kind of programming. The programming style advocated is Single Program Multiple Data (SPMD), with parallel arrays added as language primitives. Communications involving distributed arrays are handled through a standard library of collective operations. Because the underlying programming model is SPMD programming, direct calls to other communication packages are also possible from this language.

A High Level Spmd Programming Model: Hpspmd And Its Java Language Binding, Guansong Zhang, Bryan Carpenter, Geoffrey C. Fox, Xinying Li

Northeast Parallel Architecture Center

This report introduces a new language, HPJava, for parallel programming on message passing systems. The language provides a high level SPMD programming model. Through examples and performance results, the features of the new programming style, and its implementation, are illustrated.

Language Bindings For A Data-Parallel Runtime, Bryan Carpenter, Geoffrey C. Fox, Donald Leskiw, Xinying Li, Yuhong Wen

Northeast Parallel Architecture Center

The NPAC kernel runtime, developed in the PCRC (Parallel Compiler Runtime Consortium) project, is a runtime library with special support for the High Performance Fortran data model. It provides array descriptors for a generalized class of HPF-like distributed arrays, support for parallel access to their elements, and a rich library of collective communication and arithmetic operations for manipulating these arrays. The library has been successfully used as a component in experimental HPF translation systems. With prospects for early appearance of fully-featured, efficient HPF compilers looking questionable, we discuss a class of more easily implementable data-parallel language extensions that preserve many …

Considerations In Hpjava Language Design And Implementation, Guansong Zhang, Bryan Carpenter, Geoffrey C. Fox, Xinying Li, Yuhong Wen

Northeast Parallel Architecture Center

This paper discusses some design and implementation issues in the HPJava language. The language is briefly reviewed, then the class library that forms the foundation of the translation scheme is described. Through example codes, we illustrate how HPJava source codes can be translated straightforwardly to ordinary SPMD Java programs calling this library. This is followed by a discussion of the rationale for introducing the language in the first place, and of how various language features have been designed to facilitate efficient implementation.

Java/Corba Based Real-Time Infrastructure To Integrate Event-Driven Simulations, Collaboration And Distributed Object/Componentware Computing, Geoffrey C. Fox, Wojtek Furmanski, Hasan T. Ozdemir

Northeast Parallel Architecture Center

We are discussing the four major standard candidates for distributed object/componentware computing: Java, CORBA, COM and WOM within our proposed coordination framework we call Pragmatic Object Web (POW). We describe our integration approach based on multi-protocol middleware server JWORB (Java Web Object Request Broker) that currently integrates HTTP and IIOP and which we now further develop to also support COM and WOM core functionalities. We are also experimenting with visual data ow authoring front-ends using NPAC WebFlow system on top of JWORB based software bus. Finally, we illustrate our technologies in one major application domain- DoD Modeling and Simulation- where …

Common Runtime Support For High Performance Languages, Geoffrey C. Fox

Northeast Parallel Architecture Center

Widespread adoption of parallel computing depends on the availability of improved software environments. An essential component of these environments will be high-level languages. Several languages for exploiting data-parallelism (or task-parallelism) have been developed, or are under development. The stated goal of this project has been to provide a public domain infrastructure for runtime support of these high-level languages. The targeted languages include parallel versions of Fortran and C++, but our intention has been to provide uniform runtime support for many source languages.

Reflective Remote Method Invocation, George K. Thiruvathukal, Lovely S. Thomas, Andy T. Korczynski

Computer Science: Faculty Publications and Other Works

Remote Method Invocation (RMI) is available in the current Java language design and implementation, providing the much-needed capability of allowing objects running in different Java processes to collaborate using a variation on the popular Remote Procedure Call (RPC).

Although RMI provides features which are desirable for high-performance distributed computing, its design and implementation are deficient in key areas of importance to the high-performance computing community in general. This paper addresses the key deficiencies of RMI and how these deficiencies affect the design and implementation of distributed object applications.

Reflective RMI (RRMI) is an open RMI implementation which makes better use …

Object-Oriented Programming And Parallelism, Atanas Radenski

Mathematics, Physics, and Computer Science Faculty Articles and Research

Initially, object-orientation and parallelism originated and developed as separate and relatively independent areas. During the last decade, however, more and more researchers were attracted by the benefits from a potential marriage of the two powerful paradigms. Numerous research projects and an increasing number of practical applications were aimed at different forms of amalgamation of parallelism with object-orientation. It has been realized that parallelism is a inherently needed enhancement for the traditional object-oriented programming (OOP) paradigm, and that object orientation can add significant flexibility to the parallel programming paradigm.

Module Embedding, Atanas Radenski

Mathematics, Physics, and Computer Science Faculty Articles and Research

This paper proposes a code reuse mechanism called module embedding that enables the building of new modules from existing ones through inheritance, overriding of procedures, and overriding of types; the paper also describes an implementation scheme for this mechanism. Module embedding is beneficial when modules and classes are used in combination and need to be extended together, or when modules are more appropriate medium than classes.

Ta Da! - The Text Adventure Design Assistant A Visual Tool For The Development Of Adventure Games, Sean Molley

Masters Theses & Specialist Projects

In this paper, I survey past and present tools available to text adventure game authors, and then describe a new product: the Text Adventure Design Assistant (TA DA!), a visual programming system for creating text adventure games. My system consists of two parts: an abstract framework which defines an archetypical game, and a user interface which allows for the construction of games in a visual manner by manipulating the elements of the abstract game to produce a concrete design. The two most popular contemporary programming languages for creating text adventure games, TADS and Inform, are compared and contrasted, and my …

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.

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.

Technologies For Ubiquitous Supercomputing: A Java Interface To The Nexus Communication System, Ian Foster, George K. Thiruvathukal, Steven Tuecke

Computer Science: Faculty Publications and Other Works

We use the term ubiquitous supercomputing to refer to systems that integrate low- and mid-range computing systems, advanced networks and remote high-end computers with the goal of enhancing the computational power accessible from local environments. Such systems promise to enable new applications in areas as diverse as smart instruments and collaborative environments. However, they also demand tools for transporting code between computers and for establishing flexible, dynamic communication structures. In this article, we propose that these requirements be satisfied by introducing Java classes that implement the global pointer and remote service request mechanisms defined by a communication library called Nexus. …

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+)