Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 30 of 34
Full-Text Articles in Physical Sciences and Mathematics
Measurement Of Triple Gauge Wwγ Couplings At Lep2 Using Photonic Events, R. Barate, Manoj Thulasidas
Measurement Of Triple Gauge Wwγ Couplings At Lep2 Using Photonic 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 Δκγ and λγ. The results from the fit to the cross sections and to the energy and angular distributions of the photons are: Δκγ=0.05+1.15−1.10(stat)±0.25(syst), λγ=−0.05+1.55−1.45(stat)±0.30(syst).
Tuple Source Relational Model: A Source-Aware Data Model For Multidatabases, Ee Peng Lim, Roger Hsiang-Li Chiang, Yinyan Cao
Tuple Source Relational Model: A Source-Aware Data Model For Multidatabases, Ee Peng Lim, Roger Hsiang-Li Chiang, Yinyan Cao
Research Collection School Of Computing and Information Systems
In some integration projects, complete integration of database instances may not be necessary. It may also be too costly and impossible to do so due to poor local data quality and insufficient instance-level knowledge. In this research, we study how multidatabases with global schemas should be represented and manipulated when the data instances from the local databases do not require to be fully integrated. We propose the tuple source (TS) relational model to represent multidatabases under such an integration requirement. This model extends the classical relational model by augmenting every relation with a source attribute to identify the local database …
Web Bags: Are They Useful In A Web Warehouse?, Sourav S. Bhowmick, Sanjay Kumar Madria, Wee-Keong Ng, Ee Peng Lim
Web Bags: Are They Useful In A Web Warehouse?, Sourav S. Bhowmick, Sanjay Kumar Madria, Wee-Keong Ng, Ee Peng Lim
Research Collection School Of Computing and Information Systems
Sets and bags are closely related structures. A bag is different from a set in that it is sensitive to the number of times an element occurs while a set is not. In this paper, we introduce the concept of web bag in a web warehouse as a part of our Web Information Coupling System(WICS). Informally, a web bag is a web table which allows multiple occurrences of identical web tuples. Web bag helps to discover useful knowledge from a web table such as visible documents (or web sites), luminous documents and luminous paths. We formally discuss the semantics and …
A Framework For Sharing Handwritten Notes, Richard C. Davis, James Lin, Jason A. Brotherton, James A. Landay, Morgan N. Price, Bill N. Schilit
A Framework For Sharing Handwritten Notes, Richard C. Davis, James Lin, Jason A. Brotherton, James A. Landay, Morgan N. Price, Bill N. Schilit
Research Collection School Of Computing and Information Systems
NotePals is an ink-based, collaborative note taking application that runs on personal digital assistants (PDAs). Meeting participants write notes in their own handwriting on a PDA. These notes are shared with other participants by synchronizing later with a shared note repository that can be viewed using a desktop-based web browser. NotePals is distinguished by its lightweight process, interface, and hardware. This demonstration illustrates the design of two different NotePals clients and our web-based note browser.
Web Warehousing System: Design And Issues, Wee-Keong Ng, Ee Peng Lim, Sourav S. Bhowmick, Sanjay Kumar Madria
Web Warehousing System: Design And Issues, Wee-Keong Ng, Ee Peng Lim, Sourav S. Bhowmick, Sanjay Kumar Madria
Research Collection School Of Computing and Information Systems
The World Wide Web is a distributed global information resource. It contains a large amount of information that have been placed on the web independently by different organizations and thus, related information may appear across different web sites. To manage and access heterogeneous information on WWW, we have started a project of building a web warehouse, called Whoweda (Warehouse of Web Data). Currently, our work on building a web warehousing system has focused on building a data model and designing a web algebra. In this paper, we discuss design and research issues in a web warehousing system. The issues include …
Notepals: Sharing And Synchronizing Handwritten Notes With Multimedia Documents, James A. Landay, Richard C. Davis, Victor Chen, Jonathan Huang, Rebecca B. Lee, Francis Li, James Lin, Charles B. Morrey, Ben Schleimer
Notepals: Sharing And Synchronizing Handwritten Notes With Multimedia Documents, James A. Landay, Richard C. Davis, Victor Chen, Jonathan Huang, Rebecca B. Lee, Francis Li, James Lin, Charles B. Morrey, Ben Schleimer
Research Collection School Of Computing and Information Systems
NotePals is an ink-based, collaborative note taking application that runs on personal digital assistants (PDAs). Meeting participants write notes in their own handwriting on a PDA. These notes are shared with other participants by synchronizing later with a shared note repository that can be viewed using a desktop-based web browser. NotePals is distinguished by its lightweight process, interface, and hardware. This demonstration illustrates the design of two different NotePals clients and our web-based note browser.
Information Coupling In Web Databases, Sourav S. Bhowmick, Wee-Keong Ng, Ee Peng Lim
Information Coupling In Web Databases, Sourav S. Bhowmick, Wee-Keong Ng, Ee Peng Lim
Research Collection School Of Computing and Information Systems
Web information coupling refers to an association of topically related web documents. This coupling is initiated explicitly by a user in a web warehouse specially designed for web information. Web information coupling provides the means to derive additional, useful information from the WWW. In this paper, we discuss and show how two web operators, i.e., global web coupling and local web coupling, are used to associate related web information from the WWW and also from multiple web tables in a web warehouse. This paper discusses various issues in web coupling such as coupling semantics, coupling-compability, and coupling evaluation.
A Global Object Model For Accommodating Instance Heterogeneities, Ee Peng Lim, Roger Hsiang-Li Chiang
A Global Object Model For Accommodating Instance Heterogeneities, Ee Peng Lim, Roger Hsiang-Li Chiang
Research Collection School Of Computing and Information Systems
To completely address database integration problems in the context of multidatabase [10] and data warehousing systems, one has to examine various integration and query requirements. Due to various reasons such as poor data quality in local databases, ongoing local database updates, and instance heterogeneities, some instance differences have to be accommodated by the integrated databases. We have therefore proposed a new object-oriented global data model, called OORA, that can accommodate attribute and relationship instance heterogeneities in the integrated database. In addition, the OORA model has been designed to allow database integrators and end users to query both the local and …
Searches For The Neutral Higgs Bosons Of The Mssm In E+E- Collisions At Centre-Of-Mass Energies Of 181-184 Gev, Barate, R.; Et Al., M. Thulasidas
Searches For The Neutral Higgs Bosons Of The Mssm In E+E- Collisions At Centre-Of-Mass Energies Of 181-184 Gev, Barate, R.; Et Al., M. Thulasidas
Research Collection School Of Computing and Information Systems
The data collected by ALEPH at LEP at centre-of-mass energies ranging from 181 to 184 GeV, corresponding to an integrated luminosity of 57 pb−1, are analysed to search for pair-produced neutral Higgs bosons h and A, in the bb̄bb̄ and τ+τ−bb̄ final states. Two events are found in the data with 2.5 expected from standard model processes. When combined with the lower energy data collected by ALEPH and with earlier reported searches for associated hZ production, these analyses are interpreted in the context of the minimal supersymmetric extension of the standard model (MSSM). For standard choices of MSSM parameter sets, …
Design And Implementation Of A Maritime Conflict Prediction System, Wee-Keong Ng, Ee Peng Lim, Wen Jing Hsu, Yy Cao
Design And Implementation Of A Maritime Conflict Prediction System, Wee-Keong Ng, Ee Peng Lim, Wen Jing Hsu, Yy Cao
Research Collection School Of Computing and Information Systems
Maritime conflicts have serious impacts on Singapore and the surrounding region both economically and environmentally. This is particularly severe for conflicts such as collisions between large vessels or tankers carrying oil and chemicals. Thus, it is in the interests of the Maritime and Port Authority of Singapore (MPA) to avoid collisions or near-collisions among such vessels navigating through Singapore waters. Existing systems used by MPA predict potential maritime conflicts arising within a short and fixed time horizon. The system produces inconsequential warnings that are often ignored. In this paper, we describe an advanced computerbased system designed to assist in the …
Join Processing In Web Databases, Sourav S. Bhowmick, Wee-Keong Ng, Ee Peng Lim
Join Processing In Web Databases, Sourav S. Bhowmick, Wee-Keong Ng, Ee Peng Lim
Research Collection School Of Computing and Information Systems
Recently, there has been increasing interests in data models and query languages for unstructured data in the World Wide Web. When web data is harnessed in a web warehouse, new and useful information can be derived through appropriate information manipulation. In our web warehousing project, we introduce a new operator called the web join. Like its relational counterpart, web join combines information from two web tables to yield a new web table. This paper discusses various issues in web join such as join semantics, joinability, and join evaluation.
Modelling Medical Decisions In Dynamol: A New General Framework Of Dynamic Decision Analysis, Tze-Yun Leong, Cungen Cao
Modelling Medical Decisions In Dynamol: A New General Framework Of Dynamic Decision Analysis, Tze-Yun Leong, Cungen Cao
Research Collection School Of Computing and Information Systems
Dynamic decision analysis concerns decision problems in which both time and uncertainty are explicitly considered. We present a new dynamic decision analysis framework, called DynamoL, that supports graphical presentation of the decision factors in multiple perspectives. To alleviate the difficulty in assessing conditional probabilities over time in dynamic decision models, DynaMoL incorporates a Bayesian learning system to automatically learn the probabilistic parameters from large medical databases. We describe the DynaMoL modeling and learning architecture through a medical decision problem on the optimal follow-up schedule for patients after curative colorectal cancer surgery. We also show that the modeling experience and results …
The Forward-Backward Asymmetry For Charm Quarks At The Z, R. Barate, Manoj Thulasidas
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
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.
Scalar Quark Searches In E+E- Collisions At √S = 181 - 184 Gev, Barate, R.; Et Al., M. Thulasidas
Scalar Quark Searches In E+E- Collisions At √S = 181 - 184 Gev, Barate, R.; Et Al., M. Thulasidas
Research Collection School Of Computing and Information Systems
Searches for scalar top, scalar bottom and degenerate scalar quarks have been performed with data collected with the ALEPH detector at LEP. The data sample consists of 57 pb−1 taken at s = 181–184 GeV. No evidence for scalar top, scalar bottom or degenerate scalar quarks was found in the channels t̃→cχ, t̃→bℓν̃, b̃→bχ, and q̃→qχ. From the channel t̃→cχ a limit of 74 GeV/c2has been set on the scalar top quark mass, independent of the mixing angle. This limit assumes a mass difference between the t̃ and the χ in the range 10–40 GeV/c2. From the channel t̃→bℓν̃ the …
A Measurement Of The Inclusive B → Sγ Branching Ratio, R. Barate, Manoj Thulasidas
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
Database Selection Techniques For Routing Bibliographic Queries, Ee Peng Lim, Wee-Keong Ng, Jian Xu, Yinyan Cao
Database Selection Techniques For Routing Bibliographic Queries, Ee Peng Lim, Wee-Keong Ng, Jian Xu, Yinyan Cao
Research Collection School Of Computing and Information Systems
No abstract provided.
The New Aleph Silicon Vertex Detector, D. Creanza, Manoj Thulasidas
The New Aleph Silicon Vertex Detector, D. Creanza, Manoj Thulasidas
Research Collection School Of Computing and Information Systems
The ALEPH collaboration, in view of the importance of effective vertex detection for the Higgs boson search at LEP 2, decided to upgrade the previous vertex detector. Main changes were an increased length (+/- 20 cm), a higher granularity for r phi view (50 mu m), a new preamplifier (MX7 rad hard chip), a polymide (upilex) fan-out on z side to carry the signals from the strips to the front-end electronics outside the fiducial region reducing consequently the passive material in the central region by a factor of two. The detector, the running experience and its performance will be described. …
Resonant Structure And Flavour Tagging In The Bπ± System Using Fully Reconstructed B Decays, Barate, R.; Et Al., M. Thulasidas
Resonant Structure And Flavour Tagging In The Bπ± System Using Fully Reconstructed B Decays, Barate, R.; Et Al., M. Thulasidas
Research Collection School Of Computing and Information Systems
No abstract provided.
Measurement Of The W Mass By Direct Reconstruction In E+E- Collisions At 172 Gev, Barate, R.; Et Al., M. Thulasidas
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
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.
A Signcryption Scheme With Signature Directly Verifiable By Public Key, Feng Bao, Robert H. Deng
A Signcryption Scheme With Signature Directly Verifiable By Public Key, Feng Bao, Robert H. Deng
Research Collection School Of Computing and Information Systems
Signcryption, first proposed by Zheng, is a cryptographic primitive which combines both the functions of digital signature and public key encryption in a logical single step, and with a computational cost significantly lower than that needed by the traditional signature-then-encryption approach. In Zheng's scheme, the signature verification can be done either by the recipient directly (using his private key) or by engaging a zero-knowledge interative protocol with a third party, without disclosing recipient's private key. In this note, we modify Zheng's scheme so that the recipient's private key is no longer needed in signature verification. The computational cost of the …
Four-Jet Final State Production In E+E- Collisions At Centre-Of-Mass Energies Ranging From 130 To 184 Gev, R. Barate, Manoj Thulasidas
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 …
Measurement Of The Axial-Vector Τ Spectral Functions And Determination Of Αs (M2Τ) From Hadronic Τ Decays, R. Barate, M. Thulasidas
Measurement Of The Axial-Vector Τ Spectral Functions And Determination Of Αs (M2Τ) From Hadronic Τ Decays, R. Barate, M. Thulasidas
Research Collection School Of Computing and Information Systems
An analysis based on 124 000 selected ττ pairs recorded by the ALEPH detector at LEP provides the vector (V)(V) and axial-vector (A)(A) spectral functions of hadronic ττ decays together with their total widths. This allows the evaluation of finite energy chiral sum rules that are weighted integrals over the (V−A)(V−A) spectral functions. In addition, a precise measurement of αsαs along with a determination of nonperturbative contributions at the ττ mass scale is performed. The experimentally and theoretically most robust determination of αs(M2τ)αs(Mτ2) is obtained from the (V+A)(V+A) fit that yields αs(M2τ)=0.334±0.022αs(Mτ2)=0.334±0.022 giving αs(M2Z)=0.1202±0.0027αs(MZ2)=0.1202±0.0027 after the extrapolation to the mass …
Observation Of Doubly-Charmed B Decays At Lep, R. Barate, M. Thulasidas
Observation Of Doubly-Charmed B Decays At Lep, R. Barate, M. Thulasidas
Research Collection School Of Computing and Information Systems
A search for doubly-charmed B decays with both charmed mesons reconstructed is performed, using about 3.8 million hadronic Z decays recorded with the ALEPH detector at LEP. A clear signal is observed in the channels B→DsD¯(X)B→DsD¯(X) and B→DD¯(X)B→DD¯(X) (where D can be either a D00, a D++ or a D∗+∗+), providing the first direct evidence for doubly-charmed B decays involving no DsDs production. Evidence for associated K0SKS0 and K±K± production in the decays B→DD¯(X)B→DD¯(X) is also presented and some candidates for completely reconstructed decays B→DsD¯(nπ)B→DsD¯(nπ), B→DD¯K0SB→DD¯KS0 and B→DD¯K±B→DD¯K± are observed. Furthermore, candidates for the two-body Cabibbo suppressed decays B0→D∗−D∗+B0→D∗−D∗+ and …
Measurement Of The Fraction Of Hadronic Z Decays Into Charm Quark Pairs, R. Barate, M. Thulasidas
Measurement Of The Fraction Of Hadronic Z Decays Into Charm Quark Pairs, R. Barate, M. Thulasidas
Research Collection School Of Computing and Information Systems
The full statistics of hadronic Z decays collected with the ALEPH detector are analysed to measure, by three methods, the ratio, RcRc, of the partial decay width of the Z into cc¯cc¯ quarks to the total hadronic width. One method uses the inclusive pp and p⊥p⊥ spectra of electrons. The other two use a double-tagging technique to measure RcRc independently of the charm-tagging efficiency. In one, the tagging procedure uses the reconstruction of high momentum charmed mesons (D∗+D∗+, D+D+ and \({\rm D^0}$) to detect the charm quarks. In the other, a charm quark is tagged from the D∗D∗'s reconstructed in …
Studies Of Quantum Chromodynamics With The Aleph Detector, R. Barate, M. Thulasidas
Studies Of Quantum Chromodynamics With The Aleph Detector, R. Barate, M. Thulasidas
Research Collection School Of Computing and Information Systems
No abstract provided.
An Upper Limit On The Τ Neutrino Mass From Three- And Five-Prong Tau Decays, R. Barate, M. Thulasidas
An Upper Limit On The Τ Neutrino Mass From Three- And Five-Prong Tau Decays, R. Barate, M. Thulasidas
Research Collection School Of Computing and Information Systems
A bound on the tau neutrino mass is established using the data collected from 1991 to 1995 at s√≃mZ with the ALEPH detector. Two separate limits are derived by fitting the distribution of visible energy vs invariant mass in τ−→2π−π+ντ and τ−→3π−2π+(π0)ντ decays. The two results are combined to obtain a 95% confidence level upper limit of 18.2 MeV/c2 on the mass of the tau neutrino.
Search For Evidence Of Compositeness At Lep I, R. Barate, M. Thulasidas
Search For Evidence Of Compositeness At Lep I, R. Barate, M. Thulasidas
Research Collection School Of Computing and Information Systems
Extensive searches for evidence of compositeness of quarks and leptons have been made in the complete set of ALEPH data from LEP running at the Z peak. These include searches for radiative and weak decays of excited fermions, produced either in pairs or singly, and a scalar partner of the Z. Coupling and branching ratio limits deduced from these searches are presented.
Search For Supersymmetry With A Dominant R-Parity Violating Llē Coupling In E+E- Collisions At Centre-Of-Mass Energies Of 130 Gev To 172 Gev, R. Barate, M. Thulasidas
Search For Supersymmetry With A Dominant R-Parity Violating Llē Coupling In E+E- Collisions At Centre-Of-Mass Energies Of 130 Gev To 172 Gev, R. Barate, M. Thulasidas
Research Collection School Of Computing and Information Systems
A search for pair-production of supersymmetric particles under the assumption that R-parity is violated via a dominant LLE¯LLE¯ coupling has been performed using the data collected by ALEPH at centre-of-mass energies of 130–172 GeV. The observed candidate events in the data are in agreement with the Standard Model expectation. This is translated into lower limits on the mass of charginos, neutralinos, sleptons, sneutrinos and squarks. For instance, charginos with masses less than 73 GeV/c2c2 and neutralinos with masses less than 23 GeV/c2c2 are excluded at 95% confidence level for any generation structure of the LLE¯LLE¯ coupling, and for neutralino, slepton …