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Do Accurate Earnings Forecasts Facilitate Superior Investment Recommendations?, Roger Loh, G. Mujtaba Mian May 2006

Do Accurate Earnings Forecasts Facilitate Superior Investment Recommendations?, Roger Loh, G. Mujtaba Mian

Research Collection Lee Kong Chian School Of Business

We find that analysts who issue more accurate earnings forecasts also issue more profitable stock recommendations. The average factor-adjusted return associated with the recommendations of analysts in the highest accuracy quintile exceeds the corresponding return for analysts in the lowest accuracy quintile by 1.27% per month. Our findings provide indirect empirical support for valuation models in the accounting and finance literatures (e.g., Ohlson, 1995) that emphasize the role of future earnings in predicting stock price movements. Our results also suggest that imperfectly efficient markets reward information gatherers, such as security analysts, for their costly activities in generating superior earnings forecasts.

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Evaluation Of Time-Varying Availability In Multi-Echelon Spare Parts Systems With Passivation, Hoong Chuin Lau, Huawei Song, Chuen Teck See, Siew Yen Cheng Apr 2006

Evaluation Of Time-Varying Availability In Multi-Echelon Spare Parts Systems With Passivation, Hoong Chuin Lau, Huawei Song, Chuen Teck See, Siew Yen Cheng

Research Collection School Of Computing and Information Systems

The popular models for repairable item inventory, both in the literature as well as practical applications, assume that the demands for items are independent of the number of working systems. However this assumption can introduce a serious underestimation of availability when the number of working systems is small, the failure rate is high or the repair time is long. In this paper, we study a multi-echelon repairable item inventory system under the phenomenon of passivation, i.e. serviceable items are passivated (“switched off”) upon system failure. This work is motivated by corrective maintenance of high-cost technical equipment in the miltary. We …

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Enterprise Agility And The Enabling Role Of Information Technology, Eric Overby, Anandhi S. Bharadwaj, V. Sambamurthy Apr 2006

Enterprise Agility And The Enabling Role Of Information Technology, Eric Overby, Anandhi S. Bharadwaj, V. Sambamurthy

Research Collection School Of Computing and Information Systems

In turbulent environments, enterprise agility, that is, the ability of firms to sense environmental change and respond readily, is an important determinant of firm success. We define and deconstruct enterprise agility, delineate enterprise agility from similar concepts in the business research literature, explore the underlying capabilities that support enterprise agility, explicate the enabling role of information technology (IT) and digital options, and propose a method for measuring enterprise agility. The concepts in this paper are offered as foundational building blocks for the overall research program on enterprise agility and the enabling role of IT.

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Anonymous Signature Schemes, Guomin Yang, Duncan S. Wong, Xiaotie Deng, Huaxiong Wang Apr 2006

Anonymous Signature Schemes, Guomin Yang, Duncan S. Wong, Xiaotie Deng, Huaxiong Wang

Research Collection School Of Computing and Information Systems

Digital signature is one of the most important primitives in public key cryptography. It provides authenticity, integrity and non-repudiation to many kinds of applications. On signer privacy however, it is generally unclear or suspicious of whether a signature scheme itself can guarantee the anonymity of the signer. In this paper, we give some affirmative answers to it. We formally define the signer anonymity for digital signature and propose some schemes of this type. We show that a signer anonymous signature scheme can be very useful by proposing a new anonymous key exchange protocol which allows a client Alice to establish …

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Fisa: Feature-Based Instance Selection For Imbalanced Text Classification, Aixin Sun, Ee Peng Lim, Boualem Benatallah, Mahbub Hassan Apr 2006

Fisa: Feature-Based Instance Selection For Imbalanced Text Classification, Aixin Sun, Ee Peng Lim, Boualem Benatallah, Mahbub Hassan

Research Collection School Of Computing and Information Systems

Support Vector Machines (SVM) classifiers are widely used in text classification tasks and these tasks often involve imbalanced training. In this paper, we specifically address the cases where negative training documents significantly outnumber the positive ones. A generic algorithm known as FISA (Feature-based Instance Selection Algorithm), is proposed to select only a subset of negative training documents for training a SVM classifier. With a smaller carefully selected training set, a SVM classifier can be more efficiently trained while delivering comparable or better classification accuracy. In our experiments on the 20-Newsgroups dataset, using only 35% negative training examples and 60% learning …

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Experimental And Empirical Perspectives On Grid Resource Allocation For The Singapore Market, Danny Oh, Steven Miller, Nan Hu Apr 2006

Experimental And Empirical Perspectives On Grid Resource Allocation For The Singapore Market, Danny Oh, Steven Miller, Nan Hu

Research Collection School Of Computing and Information Systems

In this paper, we describe our work on using the Tycoon system developed by HP Labs to provide a market-based resource allocation and bidding framework for a grid. We discuss how we intend to evaluate the feasibility of the Tycoon system by measuring its economic performance using agent-based simulation experiments for a particular type of grid usage scenario, namely, the digital media market scenario. We will also discuss a related effort in collecting and using real grid data from the National Grid Pilot Platform in Singapore and how we will be using real data collected to derive actual usage patterns …

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A Practical Password-Based Two-Server Authentication And Key Exchange System, Yanjiang Yang, Robert H. Deng, Feng Bao Apr 2006

A Practical Password-Based Two-Server Authentication And Key Exchange System, Yanjiang Yang, Robert H. Deng, Feng Bao

Research Collection School Of Computing and Information Systems

Most password-based user authentication systems place total trust on the authentication server where cleartext passwords or easily derived password verification data are stored in a central database. Such systems are, thus, by no means resilient against offline dictionary attacks initiated at the server side. Compromise of the authentication server by either outsiders or insiders subjects all user passwords to exposure and may have serious legal and financial repercussions to an organization. Recently, several multiserver password systems were proposed to circumvent the single point of vulnerability inherent in the single-server architecture. However, these multiserver systems are difficult to deploy and operate …

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Efficient Client-To-Server Assignments For Distributed Virtual Environments, Nguyen Binh Duong Ta, Suiping Zhou Apr 2006

Efficient Client-To-Server Assignments For Distributed Virtual Environments, Nguyen Binh Duong Ta, Suiping Zhou

Research Collection School Of Computing and Information Systems

Distributed Virtual Environments (DVEs) are distributed systems that allow multiple geographically distributed clients (users) to interact simultaneously in a computer-generated, shared virtual world. Applications of DVEs can be seen in many areas nowadays, such as online games, military simulations, collaborative designs, etc. To support large-scale DVEs with real-time interactions among thousands or more distributed clients, a geographically distributed server architecture (GDSA) is generally needed, and the virtual world can be partitioned into many distinct zones to distribute the load among the servers. Due to the geographic distributions of clients and servers in such architectures, it is essential to efficiently assign …

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Duverger's Law And The Study Of Electoral Systems, Kenneth Benoit Apr 2006

Duverger's Law And The Study Of Electoral Systems, Kenneth Benoit

Research Collection School of Social Sciences

Since its first publication in 1951, Duverger's Political Parties has influenced an entire branch of political science devoted to the study of the political consequences of electoral laws. This essay examines the two propositions known as Duverger's law and Duverger's hypothesis, both concerned with how electoral institutions shape party systems. First explaining the propositions and their context, the essay examines their influence on political science, and concludes by assessing where future research in the area might be best concentrated.

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Sgpm: Static Group Pattern Mining Using Apriori-Like Sliding Window, John Goh, David Taniar, Ee Peng Lim Apr 2006

Sgpm: Static Group Pattern Mining Using Apriori-Like Sliding Window, John Goh, David Taniar, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Mobile user data mining is a field that focuses on extracting interesting pattern and knowledge out from data generated by mobile users. Group pattern is a type of mobile user data mining method. In group pattern mining, group patterns from a given user movement database is found based on spatio-temporal distances. In this paper, we propose an improvement of efficiency using area method for locating mobile users and using sliding window for static group pattern mining. This reduces the complexity of valid group pattern mining problem. We support the use of static method, which uses areas and sliding windows instead …

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Effect Of Changing Requirements: A Tracking Mechanism For The Analysis Workflow, Subhajit Datta, Robert Van Engelen Apr 2006

Effect Of Changing Requirements: A Tracking Mechanism For The Analysis Workflow, Subhajit Datta, Robert Van Engelen

Research Collection School Of Computing and Information Systems

Managing the effects of changing requirements remains one of the greatest challenges of enterprise software development. The iterative and incremental model provides an expedient framework for addressing such concerns. This paper presents a set of metrics - Mutation Index, Component Set, Dependency Index - and a methodology to measure the effects of requirement changes in the analysis workflow from one iteration to another. Results from a sample case study are included to highlight a usage scenario. Future directions of our work based on this mechanism are also discussed.

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Searching Substructures With Superimposed Distance, Xifeng Yan, Feida Zhu, Jiawei Han, Philip S. Yu Apr 2006

Searching Substructures With Superimposed Distance, Xifeng Yan, Feida Zhu, Jiawei Han, Philip S. Yu

Research Collection School Of Computing and Information Systems

Efficient indexing techniques have been developed for the exact and approximate substructure search in large scale graph databases. Unfortunately, the retrieval problem of structures with categorical or geometric distance constraints is not solved yet. In this paper, we develop a method called PIS (Partition-based Graph Index and Search) to support similarity search on substructures with superimposed distance constraints. PIS selects discriminative fragments in a query graph and uses an index to prune the graphs that violate the distance constraints. We identify a criterion to distinguish the selectivity of fragments in multiple graphs and develop a partition method to obtain a …

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In-Network Processing Of Nearest Neigbor Queries For Wireless Sensor Networks, Yuxia Yao, Xueyan Tang, Ee Peng Lim Apr 2006

In-Network Processing Of Nearest Neigbor Queries For Wireless Sensor Networks, Yuxia Yao, Xueyan Tang, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Wireless sensor networks have been widely used for civilian and military applications, such as environmental monitoring and vehicle tracking. The sensor nodes in the network have the abilities to sense, store, compute and communicate. To enable object tracking applications, spatial queries such as nearest neighbor queries are to be supported in these networks. The queries can be injected by the user at any sensor node. Due to the limited power supply for sensor nodes, energy efficiency is the major concern in query processing. Centralized data storage and query processing schemes do not favor energy efficiency. In this paper, we propose …

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A Unified Log-Based Relevance Feedback Scheme For Image Retrieval, Steven Hoi, Michael R. Lyu, Rong Jin Apr 2006

A Unified Log-Based Relevance Feedback Scheme For Image Retrieval, Steven Hoi, Michael R. Lyu, Rong Jin

Research Collection School Of Computing and Information Systems

Relevance feedback has emerged as a powerful tool to boost the retrieval performance in content-based image retrieval (CBIR). In the past, most research efforts in this field have focused on designing effective algorithms for traditional relevance feedback. Given that a CBIR system can collect and store users' relevance feedback information in a history log, an image retrieval system should be able to take advantage of the log data of users' feedback to enhance its retrieval performance. In this paper, we propose a unified framework for log-based relevance feedback that integrates the log of feedback data into the traditional relevance feedback …

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A Hybrid Scatter Search/Electromagnetism Meta-Heuristic For Project Scheduling, Dieter Debels, Bert De Reyck, Roel Leus, Mario Vanhoucke Mar 2006

A Hybrid Scatter Search/Electromagnetism Meta-Heuristic For Project Scheduling, Dieter Debels, Bert De Reyck, Roel Leus, Mario Vanhoucke

Research Collection Lee Kong Chian School Of Business

In the last few decades, several effective algorithms for solving the resource-constrained project scheduling problem have been proposed. However, the challenging nature of this problem, summarised in its strongly NP-hard status, restricts the effectiveness of exact optimisation to relatively small instances. In this paper, we present a new meta-heuristic for this problem, able to provide near-optimal heuristic solutions for relatively large instances. The procedure combines elements from scatter search, a generic population-based evolutionary search method, and from a recently introduced heuristic method for the optimisation of unconstrained continuous functions based on an analogy with electromagnetism theory. We present computational …

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Tacit Knowledge, Nonaka And Takeuchi Seci Model And Informal Knowledge Processes, Siu Loon Hoe Mar 2006

Tacit Knowledge, Nonaka And Takeuchi Seci Model And Informal Knowledge Processes, Siu Loon Hoe

Research Collection School Of Computing and Information Systems

The organizational behavior and knowledge management literature has devoted a lot attention on how structural knowledge processes enhance learning. There has been little emphasis on the informal knowledge processes and the construct remains undefined. The purpose of this paper is to highlight the importance of informal knowledge processes, propose a definition for these processes and link them to the socialization and internalization processes suggested by Nonaka and Takeuchi in the SECI model. The paper offers a fresh perspective on how informal knowledge processes in organizations help to enhance the organization’s learning capability. It will enable scholars and managers to have …

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Fortifying Password Authentication In Integrated Healthcare Delivery Systems, Yanjiang Yang, Robert H. Deng, Feng Bao Mar 2006

Fortifying Password Authentication In Integrated Healthcare Delivery Systems, Yanjiang Yang, Robert H. Deng, Feng Bao

Research Collection School Of Computing and Information Systems

Integrated Delivery Systems (IDSs) now become a primary means of care provision in healthcare domain. However, existing password systems (under either the single-server model or the multi-server model) do not provide adequate security when applied to IDSs. We are thus motivated to present a practical password authentication system built upon a novel two-server model. We generalize the two-server model to an architecture of a single control server supporting multiple service servers, tailored to the organizational structure of IDSs. The underlying user authentication and key exchange protocols we propose are password-only, neat, efficient, and robust against off-line dictionary attacks mounted by …

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Crosscutting Score: An Indicator Metric For Aspect Orientation, Subhajit Datta Mar 2006

Crosscutting Score: An Indicator Metric For Aspect Orientation, Subhajit Datta

Research Collection School Of Computing and Information Systems

Aspect Oriented Programming (AOP) provides powerful techniques for modeling and implementing enterprise software systems. To leverage its full potential, AOP needs to be perceived in the context of existing methodologies such as Object Oriented Programming (OOP). This paper addresses an important question for AOP practitioners - how to decide whether a component is best modeled as a class or an aspect? Towards that end, we present an indicator metric, the Crosscutting Score and a method for its calculation and interpretation. We will illustrate our approach through a sample calculation.

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Agility Measurement Index: A Metric For The Crossroads Of Software Development Methodologies, Subhajit Datta Mar 2006

Agility Measurement Index: A Metric For The Crossroads Of Software Development Methodologies, Subhajit Datta

Research Collection School Of Computing and Information Systems

Software engineering's journey to maturity has been marked by the advent of different development methodologies. While each paradigm has its context and cognoscenti, project teams are often faced with the choice of one approach over another in the grind of delivering software on time and within budget. In this paper, we briefly review the three major techniques of addressing enterprise software development, namely the Waterfall, Unified and Extreme styles. The metric Agility Measurement Index is then proposed, which helps organizations choose the methodology that best suites a particular project.

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Threading And Autodocumenting News Videos: A Promising Solution To Rapidly Browse News Topics, Xiao Wu, Chong-Wah Ngo, Qing Li Mar 2006

Threading And Autodocumenting News Videos: A Promising Solution To Rapidly Browse News Topics, Xiao Wu, Chong-Wah Ngo, Qing Li

Research Collection School Of Computing and Information Systems

This paper describes the techniques in threading and autodocumenting news stories according to topic themes. Initially, we perform story clustering by exploiting the duality between stories and textual-visual concepts through a co-clustering algorithm. The dependency among stories of a topic is tracked by exploring the textual-visual novelty and redundancy of stories. A novel topic structure that chains the dependencies of stories is then presented to facilitate the fast navigation of the news topic. By pruning the peripheral and redundant news stories in the topic structure, a main thread is extracted for autodocumentary

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Publicly Verifiable Ownership Protection For Relational Databases, Yingjiu Li, Robert H. Deng Mar 2006

Publicly Verifiable Ownership Protection For Relational Databases, Yingjiu Li, Robert H. Deng

Research Collection School Of Computing and Information Systems

Today, watermarking techniques have been extended from the multimedia context to relational databases so as to protect the ownership of data even after the data are published or distributed. However, all existing watermarking schemes for relational databases are secret key based, thus require a secret key to be presented in proof of ownership. This means that the ownership can only be proven once to the public (e.g., to the court). After that, the secret key is known to the public and the embedded watermark can be easily destroyed by malicious users. Moreover, most of the existing techniques introduce distortions to …

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Multivariate Stochastic Volatility: A Review, Manabu Asai, Michael Mcaleer, Jun Yu Mar 2006

Multivariate Stochastic Volatility: A Review, Manabu Asai, Michael Mcaleer, Jun Yu

Research Collection School Of Economics

The literature on multivariate stochastic volatility (MSV) models has developed significantly over the last four years. This paper reviews the substantial literature on specification, estimation, and evaluation of MSV models. A wide range of MSV models is presented according to various categories, namely, (i) asymmetric models, (ii) factor models, (iii) time-varying correlation models, and (iv) alternative MSV specifications, including models based on the matrix exponential transformation, the Cholesky decomposition, and the Wishart autoregressive process. Alternative methods of estimation, including quasi-maximum likelihood, simulated maximum likelihood, and Markov chain Monte Carlo methods, are discussed and compared. Various methods of diagnostic checking and …

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Caps: Energy-Efficient Processing Of Continuous Aggregate Queries In Sensor Networks, Wen Hu, Archan Misra, Rajiv Shorey Mar 2006

Caps: Energy-Efficient Processing Of Continuous Aggregate Queries In Sensor Networks, Wen Hu, Archan Misra, Rajiv Shorey

Research Collection School Of Computing and Information Systems

In this paper, we design and evaluate an energy efficient data retrieval architecture for continuous aggregate queries in wireless sensor networks. We show how the modification of precision in one sensor affects the sample-reporting frequency of other sensors, and how the precisions of a group of sensors may be collectively modified to achieve the target quality of information (QoI) with higher energy-efficiency. The proposed collective adaptive precision setting (CAPS) architecture is then extended to exploit the observed temporal correlation among successive sensor samples for even greater energy efficiency. Detailed simulations with synthetic and real data traces demonstrate how the combination …

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Robust Classification Of Eeg Signal For Brain-Computer Interface, Manoj Thulasidas, Cuntai Guan, Jiankang Wu Mar 2006

Robust Classification Of Eeg Signal For Brain-Computer Interface, Manoj Thulasidas, Cuntai Guan, Jiankang Wu

Research Collection School Of Computing and Information Systems

We report the implementation of a text input application (speller) based on the P300 event related potential. We obtain high accuracies by using an SVM classifier and a novel feature. These techniques enable us to maintain fast performance without sacrificing the accuracy, thus making the speller usable in an online mode. In order to further improve the usability, we perform various studies on the data with a view to minimizing the training time required. We present data collected from nine healthy subjects, along with the high accuracies (of the order of 95% or more) measured online. We show that the …

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More Efficient Estimation In Nonparametric Regression With Nonparametric Autocorrelated Errors, Liangjun Su, Aman Ullah Feb 2006

More Efficient Estimation In Nonparametric Regression With Nonparametric Autocorrelated Errors, Liangjun Su, Aman Ullah

Research Collection School Of Economics

We define a three-step procedure for more efficient estimation of the nonparametric regression mean with nonparametric autocorrelated errors. The procedure is based upon a nonparametric prewhitening transformation of the dependent variable that has to be estimated from the data by a local polynomial technique. We establish the asymptotic distribution of our estimator under weak dependence conditions and show that it is more efficient than the conventional local polynomial estimator. Furthermore, we consider criterion functions based on the linear exponential family, which include the local polynomial least squares criterion as a special case. Simulation evidence suggests that significant gains can be …

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Scalable Authentication Of Mpeg-4 Streams, Yongdong Wu, Robert H. Deng Feb 2006

Scalable Authentication Of Mpeg-4 Streams, Yongdong Wu, Robert H. Deng

Research Collection School Of Computing and Information Systems

This paper presents three scalable and efficient schemes for authenticating MPEG-4 streams: the Flat Authentication Scheme, the Progressive Authentication Scheme, and the Hierarchical Authentication Scheme. All the schemes allow authentication of MPEG-4 streams over lossy networks by integrating seamlessly digital signatures and erasure correction coding with MPEG-4's fine granular scalability. A prominent feature of our schemes is their "sign once, verify many ways" property, i.e., they generate only one digital signature per compressed MPEG-4 object group, but allow clients to verify the authenticity of any down-scaled version of the original signed object group.

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Energy Efficiency And Capacity For Tcp Traffic In Multi-Hop Wireless Networks, Sorav Bansal, Rajeev Shorey, Rajeev Gupta, Archan Misra Feb 2006

Energy Efficiency And Capacity For Tcp Traffic In Multi-Hop Wireless Networks, Sorav Bansal, Rajeev Shorey, Rajeev Gupta, Archan Misra

Research Collection School Of Computing and Information Systems

We study the performance metrics associated with TCP-regulated traffic in multi-hop, wireless networks that use a common physical channel (e.g., IEEE 802.11). In contrast to earlier analyses, we focus simultaneously on two key operating metrics—the energy efficiency and the transport-layer (TCP) throughput. Using analysis and simulations, we show how these metrics are strongly influenced by the radio transmission range of individual nodes. Due to tradeoffs between the individual packet transmission energy and the likelihood of retransmissions, the total energy consumption is a convex function of the number of hops (and hence, of the transmission range). On the other hand, the …

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Functional Sunspot Equilibria, Shurojit Chatterji, Subir Chattopadhyay Feb 2006

Functional Sunspot Equilibria, Shurojit Chatterji, Subir Chattopadhyay

Research Collection School Of Economics

Consider a one step forward looking model where agents believe that the equilibrium values of the state variable are determined by a function whose domain is the current value of the state variable and whose range is the value for the subsequent period. An agent's forecast for the subsequent period uses the belief, where the function that is chosen is allowed to depend on the current realization of an extrinsic random process, and is made with knowledge of the past values of the state variable but not the current value. The paper provides (and characterizes) the conditions for the existence …

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Design Synthesis From Interaction And State-Based Specifications, Jun Sun, Jin Song Dong Jan 2006

Design Synthesis From Interaction And State-Based Specifications, Jun Sun, Jin Song Dong

Research Collection School Of Computing and Information Systems

Interaction-based and state-based modeling are two complementary approaches of behavior modeling. The former focuses on global interactions between system components. The latter concentrates on the internal states of individual components. Both approaches have been proven useful in practice. One challenging and important research objective is to combine the modeling power of both effectively and then use the combination as the basis for automatic design synthesis. We present a combination of interaction-based and state-based modeling, namely, Live Sequence Charts and Z, for system specification. We then propose a way of generating distributed design from the combinations. Our approach handles systems with …

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Singapore Management University Report To Stakeholders 2006 - 2007, Singapore Management University Jan 2006

Singapore Management University Report To Stakeholders 2006 - 2007, Singapore Management University

Report to Stakeholders

SMU was founded to add diversity to higher education in Singapore, and to serve as a catalyst for change. Eight years on, the University continues to set new benchmarks for nurturing responsible leadership, developing diverse talents and spearheading research that has impact and real-world relevance. In the past academic year, SMU added a new school, graduate programmes and centres of excellence and forged new and deeper relationships with industry, academic and civic partners. These advances built on our existing strengths and moved us forward on a path of purposeful change and growth that reinforced our vision to be a premier …

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