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Internet, World Wide Web, And Creativity, Keng Siau Sep 1999

Internet, World Wide Web, And Creativity, Keng Siau

Research Collection School Of Computing and Information Systems

The growth of the Internet has been the most astonishing technological and social phenomenon of the last decade of this century. In 1990 only a few academics had heard of it; now, more than 50 million people use it. By the turn of the century, that figure could be 100–200 million. So far, the network's only constant has been that the number of new users has doubled almost every 12–18 months. Most organizations have or will soon have Internet access. The popularity of Internet provides a tremendous opportunity for individuals and organizations to explore its features and services for electronic …


Motion Tracking Of Human Mouth By Generalized Deformable Models, Syin Chan, Chong-Wah Ngo, Kok F. Lai Sep 1999

Motion Tracking Of Human Mouth By Generalized Deformable Models, Syin Chan, Chong-Wah Ngo, Kok F. Lai

Research Collection School Of Computing and Information Systems

We propose and evaluate four trackers for tracking the shape, motion and deformation of a human mouth in video sequences. The trackers are suitable for use in very low bitrate video coding systems. (C) 1999 Elsevier Science B.V. All rights reserved.


Design Approaches To Model-Based Simulation In Intelligent Computer Assisted Instruction, Bjoern Helfesrieder, Venky Shankararaman Sep 1999

Design Approaches To Model-Based Simulation In Intelligent Computer Assisted Instruction, Bjoern Helfesrieder, Venky Shankararaman

Research Collection School Of Computing and Information Systems

Model-based simulation systems have been created in various fields of engineering to train personnel or students in operation, maintenance and troubleshooting of complex devices and systems. A review of literature indicates a lack of good overviews of the approaches to system design of model-based training simulations in Intelligent Computer Assisted Instruction (ICAI). Though single systems have to some extent been evaluated with regard to their performance, an organised evaluation, especially a comparative evaluation of the systems that have been created within the field is lacking. To be able to successfully conduct an in-depth review under these conditions, we concentrate and …


Xcert Software, Inc., Keng Siau Sep 1999

Xcert Software, Inc., Keng Siau

Research Collection School Of Computing and Information Systems

Xcert’s business is in developing Internet and Intranet security enhancement technology. Xcert was founded in April 1996 by Andrew Csinger and Pat Richard and was headquartered in Vancouver, Canada. Xcert’s solution to Internet security was a public key infrastructure (PKI). PKI is a system of digital certi® cates, certi® cate authorities (CAs) and other registration authorities that verify and authenticate the validity of each party involved in an Internet transaction. Xcert’s PKI technology allows organizations of any size to issue digital certi® cates to their members. These organizations become their own CA and are empowered to issue digital certi® cates …


Wedagen: A Synthetic Web Database Generator, Pallavi Priyardarshini, Fengqiong Qin, Ee Peng Lim, Wee-Keong Ng Sep 1999

Wedagen: A Synthetic Web Database Generator, Pallavi Priyardarshini, Fengqiong Qin, Ee Peng Lim, Wee-Keong Ng

Research Collection School Of Computing and Information Systems

At the Centre for Advanced Information Systems (CAIS), a Web warehousing system is being developed to store and manipulate Web information. The system named WHOWEDA (WareHouse Of WEb DAta) stores extracted Web information as Web tables and provides several Web operators, eg. Web join, Web select, global coupling, etc., to manipulate Web tables. During the implementation of WHOWEDA, it is necessary to perform systematic testing on the system and to evaluate its system performance. While it is possible for WHOWEDA to be tested or evaluated using actual Web pages downloaded from WWW, the amount of time required for such testing …


Research Issues In Web Data Mining, Sanjay Kumar Madria, Sourav S. Bhowmick, Wee-Keong Ng, Ee Peng Lim Sep 1999

Research Issues In Web Data Mining, Sanjay Kumar Madria, Sourav S. Bhowmick, Wee-Keong Ng, Ee Peng Lim

Research Collection School Of Computing and Information Systems

In this paper, we discuss mining with respect to web data referred here as web data mining. In particular, our focus is on web data mining research in context of our web warehousing project called WHOWEDA (Warehouse of Web Data). We have categorized web data mining into threes areas; web content mining, web structure mining and web usage mining. We have highlighted and discussed various research issues involved in each of these web data mining category. We believe that web data mining will be the topic of exploratory research in near future.


Locating Web Information Using Web Checkpoints, Aik Kee Luah, Wee-Keong Ng, Ee Peng Lim, Wee Peng Lee, Yinyan Cao Sep 1999

Locating Web Information Using Web Checkpoints, Aik Kee Luah, Wee-Keong Ng, Ee Peng Lim, Wee Peng Lee, Yinyan Cao

Research Collection School Of Computing and Information Systems

Conventional search engines locate information by letting users establish a single web checkpoint1. By specifying one or more keywords, users direct search engines to return a set of documents that contain those keywords. From the documents (links) returned by search engines, user proceed to further probe the WWW from there. Hence, these initial set of documents (contingent upon the occurrence of keyword(s)) serve as a web checkpoint. Generally, these links are numerous and may not result in much fruitful searches. By establishing multiple web checkpoints, a richer and controllable search procedure can be constructed to obtain more relevant Web information. …


Non-Repudiation In An Agent-Based E-Commerce System, Chin Chuan Liew, Wee-Keong Ng, Ee Peng Lim, Beng Suang Tan, Kok-Leong Ong Sep 1999

Non-Repudiation In An Agent-Based E-Commerce System, Chin Chuan Liew, Wee-Keong Ng, Ee Peng Lim, Beng Suang Tan, Kok-Leong Ong

Research Collection School Of Computing and Information Systems

Abecos is an agent-based e-commerce system under development at the Nanyang Technological University. A key factor in making this system usable in practice is strict security controls. One aspect of security is the provision of non-repudiation services. As protocols for non-repudiation have focused on -message non-repudiation, its adaptation to afford non-repudiation in a communication session for two agents in Abecos is inefficient. In this work, we investigate and propose a protocol for enforcing non-repudiation in a session. The protocol is believed to be applicable in any e-commerce system; agent- or not agent-based.


Artificial Intelligence Approach To Analyzing The Bullwhip Effect In Supply Chains, C. Qing, Keng Siau Aug 1999

Artificial Intelligence Approach To Analyzing The Bullwhip Effect In Supply Chains, C. Qing, Keng Siau

Research Collection School Of Computing and Information Systems

Supply chain management critically affects businesses’ abilities to obtain and sustain competitive advantages. The bullwhip effect, however, presents a challenge for successful supply chain management by amplifying demands in the supply chains. This paper presents a systematic approach to tackle the issue of bullwhip effect. Firstly, we define the supply chain under a multiagent framework. Secondly, the group problem solving paradigm, which is a rule learning approach, is proposed to enhance the decision making process within the supply chain framework. The group problem solving paradigm is also suggested as a means to alleviate the bullwhip effect. The paper concludes with …


A Recurring Improvisational Methodology For Change Management In Erp Implementation, Michelle Sieber, Fiona Fui-Hoon Nah Aug 1999

A Recurring Improvisational Methodology For Change Management In Erp Implementation, Michelle Sieber, Fiona Fui-Hoon Nah

Research Collection School Of Computing and Information Systems

Change has become an ongoing phenomenon and business process re-engineering has become a necessity for survival of organizations as we approach the 21st century. As participants in this ever-changing working environment, we must be innovative in managing change as it affects both our professional and personal lives. One of the innovative ways to manage change in the implementation of an enterprise resource planning (ERP) system is to adopt a comprehensive change management methodology. In this research, we propose the use of the recurring improvisational change methodology for managing such change. This research is also aimed at implementing the improvisational change …


Knowledge Sharing With Customers On The Www: Approaches By National Tourism Organizations, Xinran You, Joseph O'Leary, Fiona Fui-Hoon Nah Aug 1999

Knowledge Sharing With Customers On The Www: Approaches By National Tourism Organizations, Xinran You, Joseph O'Leary, Fiona Fui-Hoon Nah

Research Collection School Of Computing and Information Systems

The importance of knowledge management has been emphasized increasingly in recent literature. Knowledge has been regarded as the most important corporate asset in an organization (Nonaka and Takeuchi, 1995). But what is knowledge? According to Harris (1996), "when information is combined with context and experience, it becomes knowledge". Hence, knowledge is the integration of information, context, and experience (Ponelis and Fairer-Wessels, 1998). In the tourism context of this paper, there are two components of knowledge: (1) customer knowledge--understanding of customers by marketers that leads to more effective marketing actions; and (2) destination knowledge that either the travelers or travel experts …


Website Design: The Concepts Of Informational And Computational Equivalence, Keng Siau Aug 1999

Website Design: The Concepts Of Informational And Computational Equivalence, Keng Siau

Research Collection School Of Computing and Information Systems

“To the end users, the user interface is the system.” This slogan has been widely used in human-computer interaction field to stress the importance of user interface design. In the Internet and electronic commerce area, the website is not only the system, but it also projects an image of the organization in cyberspace. The design of websites is central to businesses as they create the first impression of organizations to visitors. For a virtual organization, the website is also the only medium that visitors rely on to form their impression of the organization. In this paper, we look at theories …


Cluster-Based Database Selection Techniques For Routing Bibliographic Queries, Jian Xu, Ee Peng Lim, Wee-Keong Ng Aug 1999

Cluster-Based Database Selection Techniques For Routing Bibliographic Queries, Jian Xu, Ee Peng Lim, Wee-Keong Ng

Research Collection School Of Computing and Information Systems

In this paper, we focus on the database selection problem in the context of a global digital library consisting of a large number of online bibliographic servers. Each server hosts a bibliographic database that contains bibliographic records each of which consists of text values for a number of pre-defined bibliographic attributes such as title, author, call number, subject, etc.. Each bibliographic database supports user queries on the bibliographic attributes. Since bibliographic records are relatively small in size, we only consider bibliographic databases that support boolean queries on the bibliographic attributes, and the query results are not ranked. While focusing on …


Camera Break Detection By Partitioning Of 2d Spatio-Temporal Images In Mpeg Domain, Chong-Wah Ngo Jun 1999

Camera Break Detection By Partitioning Of 2d Spatio-Temporal Images In Mpeg Domain, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

In this paper, we propose a new approach to detect camera cuts and wipes. The approach projects a video into two images representing the spatio-temporal continuity of a video life. Visually, these images are composed by regions of different patterns, each region represents the temporal location of a shot. The shape of a region boundary inherently classifies cut and wipe, and most importantly, marks the start and end of a wipe sequence. We hence formulate algorithms to locate the color and texture discontinuities occurring at the boundaries of image regions.


The Effectiveness Of Expert Support Technology For Decision Making: Individuals Versus Small Groups, Fiona Fui-Hoon Nah, Jiye Mao, Izak Benbasat Jun 1999

The Effectiveness Of Expert Support Technology For Decision Making: Individuals Versus Small Groups, Fiona Fui-Hoon Nah, Jiye Mao, Izak Benbasat

Research Collection School Of Computing and Information Systems

Expert support systems (ESSs) are increasingly used in organizations to support individuals and groups in decision making. Although ESSs have been shown to enhance the decision-making capabilities of individuals, their benefits in supporting group decision making are less clear. To the best of our knowledge, no empirical research has evaluated the effectiveness of the technology in the group setting or compared its usefulness for supporting individual versus group decision making. The results of this research show that ESSs benefit decision making of both individuals and groups and novices are able to gain more from ESSs than experts. The findings also …


Detection Of Gradual Transitions Through Temporal Slice Analysis, Chong-Wah Ngo, T. C. Pong, R. T. Chin Jun 1999

Detection Of Gradual Transitions Through Temporal Slice Analysis, Chong-Wah Ngo, T. C. Pong, R. T. Chin

Research Collection School Of Computing and Information Systems

In this paper, we present approaches for detecting camera cuts, wipes and dissolves based on the analysis of spatio-temporal slices obtained from videos. These slices are composed of spatial ly and temporal ly coherent regions which can be perceived as shots. In the proposed methods, camera breaks are located by performing color-texture segmentation and statistical analysis on these video slices. In addition to detecting camera breaks, our methods can classify the detected breaks as camera cuts, wipes and dissolves in an efficient manner


Notepals: Lightweight Note Sharing By The Group, For The Group, Richard C. Davis, James A. Landay, Victor Chen, Jonathan Huang, Rebecca B. Lee, Francis Li, James Lin, Charles B. Morrey, Morgan N. Price, Bill N. Schilit May 1999

Notepals: Lightweight Note Sharing By The Group, For The Group, Richard C. Davis, James A. Landay, Victor Chen, Jonathan Huang, Rebecca B. Lee, Francis Li, James Lin, Charles B. Morrey, Morgan N. Price, Bill N. Schilit

Research Collection School Of Computing and Information Systems

NotePals is a lightweight note sharing system that gives group members easy access to each others experiences through their personal notes. The system allows notes taken by group members in any context to be uploaded to a shared repository. Group members view these notes with browsers that allow them to retrieve all notes taken in a given context or to access notes from other related notes or documents. This is possible because NotePals records the context in which each note is created (e.g., its author, subject, and creation time). The system is lightweight because it fits easily into group members …


Information Modeling And Method Engineering: A Psychological Perspective, Keng Siau Apr 1999

Information Modeling And Method Engineering: A Psychological Perspective, Keng Siau

Research Collection School Of Computing and Information Systems

Information modeling is the cornerstone of information systems analysis and design. Information models, the products of information modeling, not only provide the abstractions required to facilitate communication between the analysts and end users, but they also provide a formal basis for developing tools and techniques used in information systems development. The process of designing, constructing, and adapting information modeling methods for information systems development is known as method engineering. Despite the pivotal role of modeling methods in successful information systems development, most modeling methods are designed based on common sense and intuition of the method designers with little or no …


Pi-Web Join In A Web Warehouse, Sourav S. Bhowmick, Sanjay Kumar Madria, Wee-Keong Ng, Ee Peng Lim Apr 1999

Pi-Web Join In A Web Warehouse, Sourav S. Bhowmick, Sanjay Kumar Madria, Wee-Keong Ng, Ee Peng Lim

Research Collection School Of Computing and Information Systems

With the enormous amount of data stored in the World Wide Web, it is increasingly important to design and develop powerful web warehousing tools. The key objective of our web warehousing project, called WHOWEDA (Warehouse of Web Data), is to design and implement a web warehouse that materializes and manages useful information from the Web. In this paper, we introduce the concept of Pi-web join in the context of WHOWEDA. Pi-web join operator is a web information manipulation operator to combine relevant web information residing in two web tables. Informally, it is the combination of web join and web project …


Resource Scheduling In A High-Performance Multimedia Server, Hwee Hwa Pang, Bobby Jose, M. S. Krishnan Mar 1999

Resource Scheduling In A High-Performance Multimedia Server, Hwee Hwa Pang, Bobby Jose, M. S. Krishnan

Research Collection School Of Computing and Information Systems

Supporting continuous media data-such as video and audio-imposes stringent demands on the retrieval performance of a multimedia server. In this paper, we propose and evaluate a set of data placement and retrieval algorithms to exploit the full capacity of the disks in a multimedia server. The data placement algorithm declusters every object over all of the disks in the server-using a time-based declustering unit-with the aim of balancing the disk load. As for runtime retrieval, the quintessence of the algorithm is to give each disk advance notification of the blocks that have to be fetched in the impending time periods, …


The Window Distribution Of Idealized Tcp Congestion Avoidance With Variable Packet Loss, Archan Misra, Teunis J. Ott Mar 1999

The Window Distribution Of Idealized Tcp Congestion Avoidance With Variable Packet Loss, Archan Misra, Teunis J. Ott

Research Collection School Of Computing and Information Systems

This paper analyzes the stationary behavior of the TCP congestion window performing ideal congestion avoidance when the packet loss probability is not constant, but varies as a function of the window size. By neglecting the detailed window behavior during fast recovery, we are able to derive a Markov process that is then approximated by a continuous-time, continuous state space process. The stationary distribution of this process is analyzed and derived numerically and then extrapolated to obtain the stationary distribution of the TCP window. This numerical analysis enables us to predict the behavior of the TCP congestion window when interacting with …


Search For Charginos And Neutralinos In E+E- Collisions At Centre-Of-Mass Energies Near 183 Gev And Constraints On The Mssm Parameter Space, R. Barate, M. Thulasidas Jan 1999

Search For Charginos And Neutralinos In E+E- Collisions At Centre-Of-Mass Energies Near 183 Gev And Constraints On The Mssm Parameter Space, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

Searches for charginos and neutralinos are performed with the data collected by the ALEPH detector at LEP at centre-of-mass energies near 183 GeV. In these searches, it is assumed that R-parity is conserved and that the lightest neutralino is the LSP. No evidence of a signal is observed in the 57 pb−1−1 accumulated, which excludes chargino and associated neutralino production up to the kinematic limit over large regions of the MSSM parameter space. Under the assumptions of common gaugino and common sfermion masses at the unification scale, the interplay between the chargino, neutralino and slepton exclusion limits allows a lower …


A Study Of Single W Production In E+E- Collisions At √S = 161-183 Gev, R. Barate, Manoj Thulasidas Jan 1999

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) …


Search For Charged Higgs Bosons In E+E- Collisions At √S = 181-184 Gev, Barate, R.; Et Al., M. Thulasidas Jan 1999

Search For Charged Higgs Bosons In E+E- Collisions At √S = 181-184 Gev, Barate, R.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

No abstract provided.


Study Of T Decays Involving Kaons, Spectral Functions And Determination Of The Strange Quark Mass, R. Barate, M. Thulasidas Jan 1999

Study Of T Decays Involving Kaons, Spectral Functions And Determination Of The Strange Quark Mass, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

All ALEPH measurements of branching ratios of ττ decays involving kaons are summarized including a combination of results obtained with K0SKS0 and K0LKL0 detection. The decay dynamics are studied, leading to the determination of contributions from vector K∗(892)K∗(892) and K∗(1410)K∗(1410), and axial-vector K1(1270)K1(1270) and K1(1400)K1(1400) resonances. Agreement with isospin symmetry is observed among the different final states. Under the hypothesis of the conserved vector current, the spectral function for the KK¯¯¯¯¯πKK¯π mode is compared with the corresponding cross section for low energy e+e−e+e− annihilation, yielding an axial-vector fraction of (94+6−8)%(94−8+6)% for this mode. The branching ratio for ττ decay into …


One-Prong Τ Decays With Kaons, R. Barate, M. Thulasidas Jan 1999

One-Prong Τ Decays With Kaons, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

One-prong ττ decays into final states involving kaons are studied with about 161 000 τ+τ−τ+τ− events collected by the ALEPH detector from 1991 to 1995. Charged kaons are identified by dE/dx measurement, while K0LKL0's are detected through their interaction in calorimeters. Branching ratios are measured for the inclusive mode, B(τ−→K−Xντ)=(1.52±0.04±0.04)%B(τ−→K−Xντ)=(1.52±0.04±0.04)%, where X can be any system of neutral particles, and for the exclusive modesB(τ−→K−ντ)=(6.96±0.25±0.14)×10−3,B(τ−→K−π0ντ)=(4.44±0.26±0.24)×10−3,B(τ−→K−π0π0ντ)=(0.56±0.20±0.15)×10−3,B(τ−→K−π0π0π0ντ)=(0.37±0.21±0.11)×10−3,B(τ−→K−K0ντ)=(1.62±0.21±0.11)×10−3,B(τ−→K−K0π0ντ)=(1.43±0.25±0.15)×10−3,B(τ−→K0¯¯¯¯¯¯¯π−ντ)=(9.28±0.45±0.34)×10−3,B(τ−→K0¯¯¯¯¯¯¯π−π0ντ)=(3.47±0.53±0.37)×10−3,B(τ−→K−ντ)=(6.96±0.25±0.14)×10−3,B(τ−→K−π0ντ)=(4.44±0.26±0.24)×10−3,B(τ−→K−π0π0ντ)=(0.56±0.20±0.15)×10−3,B(τ−→K−π0π0π0ντ)=(0.37±0.21±0.11)×10−3,B(τ−→K−K0ντ)=(1.62±0.21±0.11)×10−3,B(τ−→K−K0π0ντ)=(1.43±0.25±0.15)×10−3,B(τ−→K0¯π−ντ)=(9.28±0.45±0.34)×10−3,B(τ−→K0¯π−π0ντ)=(3.47±0.53±0.37)×10−3,where the first error is statistical and the second is systematical. Upper limits for B(τ−→K0¯¯¯¯¯¯¯π−π0π0ντ)B(τ−→K0¯π−π0π0ντ) and B(τ−→K−K0π0π0ντ)B(τ−→K−K0π0π0ντ) are also obtained. Mass spectra in the final states are investigated in order to study the relevant dynamics.


Search For Bs0 Oscillations Using Inclusive Lepton Events, R. Barate, M. Thulasidas Jan 1999

Search For Bs0 Oscillations Using Inclusive Lepton Events, R. Barate, M. Thulasidas

Research Collection School Of Computing and Information Systems

A search for B0sBs0 oscillations is performed using a sample of semileptonic b-hadron decays collected by the ALEPH experiment during 1991–95. Compared to previous inclusive lepton analyses, the proper time resolution and b-flavour mistag rate are significantly improved. Additional sensitivity to B0sBs0 mixing is obtained by identifying subsamples of events having a B0sBs0 purity which is higher than the average for the whole data sample. Unbinned maximum likelihood amplitude fits are performed to derive a lower limit of Δms>9.5ps−1Δms>9.5ps−1 at the 95% confidence limit (95% CL). Combining with the ALEPH D−sDs−-based analyses yields Δms>9.6ps−1Δms>9.6ps−1 at 95% …


Web-Based Interlibrary Loan System, Ee Peng Lim, Schubert Foo, Cheng Hai Tan, Kwang-Yong Tan Jan 1999

Web-Based Interlibrary Loan System, Ee Peng Lim, Schubert Foo, Cheng Hai Tan, Kwang-Yong Tan

Research Collection School Of Computing and Information Systems

Interlibrary loan (ILL) system is one of the important library services provided by most public libraries. Through ILL, public libraries share their collections of reading material and library users are able to access library resources beyond their affiliated libraries. However, the present manual ILL process is inconvenient, inefficient and error-prone. In this project, we developed a system that automated many tedious procedures in the existing ILL system. The new ILL system is realized by a number of Java applets customized for librarians and library users. The new ILL system allows library users to submit ILL requests at any time using …


Determination Of The Lep Centre-Of-Mass Energy From Zγ Events, R. Barate, Manoj Thulasidas Jan 1999

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).


Monitoring The Stability Of The Aleph Vertex Detector, G. Sguazzoni, Manoj Thulasidas Jan 1999

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.