Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

Software Engineering

Singapore Management University

2007

Articles 1 - 20 of 20

Full-Text Articles in Physical Sciences and Mathematics

Location Update Versus Paging Trade-Off In Cellular Networks: An Approach Based On Vector Quantization, Abhishek Roy, Archan Misra, Sajal K. Das Dec 2007

Location Update Versus Paging Trade-Off In Cellular Networks: An Approach Based On Vector Quantization, Abhishek Roy, Archan Misra, Sajal K. Das

Research Collection School Of Computing and Information Systems

In this paper we propose two information-theoretic techniques for efficiently trading off the location update and paging costs associated with mobility management in wireless cellular networks. Previous approaches attempt to always accurately convey a mobile's movement sequence and hence, cannot reduce the signaling cost below the entropy bound. Our proposed techniques, however, exploit rate-distortion theory to arbitrarily reduce the update cost, at the expense of an increase in the corresponding paging overhead. To this end, we describe two location tracking algorithms, based on spatial quantization and temporal quantization, which first quantize the movement sequence into a smaller set of codewords, …

Go to article

Context-Aware Statistical Debugging: From Bug Predictors To Faulty Control Flow Paths, Lingxiao Jiang, Zhendong Su Nov 2007

Context-Aware Statistical Debugging: From Bug Predictors To Faulty Control Flow Paths, Lingxiao Jiang, Zhendong Su

Research Collection School Of Computing and Information Systems

Effective bug localization is important for realizing automated debugging. One attractive approach is to apply statistical techniques on a collection of evaluation profiles of program properties to help localize bugs. Previous research has proposed various specialized techniques to isolate certain program predicates as bug predictors. However, because many bugs may not be directly associated with these predicates, these techniques are often ineffective in localizing bugs. Relevant control flow paths that may contain bug locations are more informative than stand-alone predicates for discovering and understanding bugs. In this paper, we propose an approach to automatically generate such faulty control flow paths …

Go to article

Mining Modal Scenarios-Based Specifications From Execution Trace Of Reactive Systems, David Lo, Shahar Maoz, Siau-Cheng Khoo Nov 2007

Mining Modal Scenarios-Based Specifications From Execution Trace Of Reactive Systems, David Lo, Shahar Maoz, Siau-Cheng Khoo

Research Collection School Of Computing and Information Systems

Specification mining is a dynamic analysis process aimed at automatically inferring suggested specifications of a program from its execution traces. We describe a novel method, framework, and tool, for mining inter-object scenario-based specifications in the form of a UML2-compliant variant of Damm and Harels Live Sequence Charts (LSC). LSC extends the classical partial order semantics of sequence diagrams with temporal liveness and symbolic class level lifelines, in order to generate compact and expressive specifications. The output of our algorithm is a sound and complete set of statistically significant LSCs (i.e., satisfying given thresholds of support and confidence), mined from an …

Go to article

Model Checking In The Absence Of Code, Model And Properties, David Lo, Siau-Cheng Khoo Nov 2007

Model Checking In The Absence Of Code, Model And Properties, David Lo, Siau-Cheng Khoo

Research Collection School Of Computing and Information Systems

Model checking is a major approach in ensuring software correctness. It verifies a model converted from code against some formal properties. However, difficulties and programmers ’ reluctance to formalize formal properties have been some hurdles to its widespread industrial adoption. Also, with the advent of commercial off-the-shelf (COTS) components provided by third party vendors, model checking is further challenged as often only a binary version of the code is provided by vendors. Interestingly, latest instrumentation tools like PIN and Valgrind have enable execution traces to be collected dynamically from a running program. In this preliminary study, we investigate what can …

Go to article

Advances And Challenges With Data Broadcasting In Wireless Mesh Networks, Chun Tung Chou, Junaid Qadir, Joo Ghee Lim, Archan Misra Nov 2007

Advances And Challenges With Data Broadcasting In Wireless Mesh Networks, Chun Tung Chou, Junaid Qadir, Joo Ghee Lim, Archan Misra

Research Collection School Of Computing and Information Systems

Wireless mesh networks have become a promising means to provide low-cost broadband access. Many WMN applications require broadcasting data (IPTV etc.) over the WMN. This article studies how efficient data broadcast, measured in terms of broadcast latency, can be realized by exploiting two features of WMNs: the use of multiple transmission rates at the link layer and the use of multiple radio interfaces on each node. We demonstrate that by exploiting these features, broadcast latency can be reduced severalfold compared to the current default practice in wireless LANs of using the lowest transmission rate for broadcast traffic. We also discuss …

Go to article

Machine-Assisted Proof Support For Validation Beyond Simulink, Chunqing Chen, Jin Song Dong, Jun Sun Nov 2007

Machine-Assisted Proof Support For Validation Beyond Simulink, Chunqing Chen, Jin Song Dong, Jun Sun

Research Collection School Of Computing and Information Systems

Simulink is popular in industry for modeling and simulating embedded systems. It is deficient to handle requirements of high-level assurance and timing analysis. Previously, we showed the idea of applying Timed Interval Calculus (TIC) to complement Simulink. In this paper, we develop machine-assisted proof support for Simulink models represented in TIC. The work is based on a generic theorem prover, Prototype Verification System (PVS). The TIC specifications of both Simulink models and requirements are transformed to PVS specifications automatically. Verification can be carried out at interval level with a high level of automation. Analysis of continuous and discrete behaviors is …

Go to article

A Two-Phase Approach To Interactivity Enhancement For Large-Scale Distributed Virtual Environments, Nguyen Binh Duong Ta, Suiping Zhou Oct 2007

A Two-Phase Approach To Interactivity Enhancement For Large-Scale 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 even 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 …

Go to article

Sketchwizard: Wizard Of Oz Prototyping Of Pen-Based User Interfaces, Richard C. Davis, T. Scott Saponas, Michael Shilman, James A. Landay Oct 2007

Sketchwizard: Wizard Of Oz Prototyping Of Pen-Based User Interfaces, Richard C. Davis, T. Scott Saponas, Michael Shilman, James A. Landay

Research Collection School Of Computing and Information Systems

SketchWizard allows designers to create Wizard of Oz prototypes of pen-based user interfaces in the early stages of design. In the past, designers have been inhibited from participating in the design of pen-based interfaces because of the inadequacy of paper prototypes and the difficulty of developing functional prototypes. In SketchWizard, designers and end users share a drawing canvas between two computers, allowing the designer to simulate the behavior of recognition or other technologies. Special editing features are provided to help designers respond quickly to end-user input. This paper describes the SketchWizard system and presents two evaluations of our approach. The …

Go to article

Mining Modal Scenarios From Execution Traces, David Lo, Shahar Maoz, Siau-Cheng Khoo Oct 2007

Mining Modal Scenarios From Execution Traces, David Lo, Shahar Maoz, Siau-Cheng Khoo

Research Collection School Of Computing and Information Systems

Specification mining is a dynamic analysis process aimed at automatically inferring suggested specifications of a program from its execution traces. We describe a method, a framework, and a tool, for mining inter-object scenario-based specifications in the form of a UML2-compliant variant of Damm and Harel's Live Sequence Charts (LSC), which extends the classical partial order semantics of sequence diagrams with temporal liveness and symbolic class level lifelines, in order to generate compact and expressive specifications. Moreover, we use previous research work and tools developed for LSC to visualize, analyze, manipulate, test, and thus evaluate the scenario-based specifications we mine. Our …

Go to article

Performance Of Network-Coding In Multi-Rate Wireless Environments For Multicast Applications, Luiz F. M. Viera, Archan Misra, Mario Gerla Oct 2007

Performance Of Network-Coding In Multi-Rate Wireless Environments For Multicast Applications, Luiz F. M. Viera, Archan Misra, Mario Gerla

Research Collection School Of Computing and Information Systems

This paper investigates the interaction between net-work coding and link-layer transmission rate diversity in multi-hop wireless networks. By appropriately mixing data packets at intermediate nodes, network coding allows a single multicast flow to achieve higher throughput to a set of receivers. Broadcast applications can also exploit link-layer rate diversity, whereby individual nodes can transmit at faster rates at the expense of corresponding smaller coverage area. We first demonstrate how combining rate-diversity with network coding can provide a larger capacity for data dissemination of a single multicast flow, and how consideration of rate diversity is critical for maximizing system throughput. We …

Go to article

Context-Based Detection Of Clone-Related Bugs, Lingxiao Jiang, Zhendong Su, Edwin Chiu Sep 2007

Context-Based Detection Of Clone-Related Bugs, Lingxiao Jiang, Zhendong Su, Edwin Chiu

Research Collection School Of Computing and Information Systems

Studies show that programs contain much similar code, commonly known as clones. One of the main reasons for introducing clones is programmers' tendency to copy and paste code to quickly duplicate functionality. We commonly believe that clones can make programs difficult to maintain and introduce subtle bugs. Although much research has proposed techniques for detecting and removing clones to improve software maintainability, little has considered how to detect latent bugs introduced by clones. In this paper, we introduce a general notion of context-based inconsistencies among clones and develop an efficient algorithm to detect such inconsistencies for locating bugs. We have …

Go to article

Globally Distributed Software Development Project Performance: An Empirical Analysis, Narayanasamy Ramasubbu, Rajesh Krishna Balan Sep 2007

Globally Distributed Software Development Project Performance: An Empirical Analysis, Narayanasamy Ramasubbu, Rajesh Krishna Balan

Research Collection School Of Computing and Information Systems

Software firms are increasingly distributing their software development effort across multiple locations. In this paper we present the results of a two year field study that investigated the effects of dispersion on the productivity and quality of distributed software development. We first develop a model of distributed software development. We then use the model, along with our empirically observed data, to understand the consequences of dispersion on software project performance. Our analysis reveals that, even in high process maturity environments, a) dispersion significantly reduces development productivity and has effects on conformance quality, and b) these negative effects of dispersion can …

Go to article

Realizing Live Sequence Charts In System Verilog, Hai H. Wang, Shengchao Qin, Jun Sun, Jin Song Dong Aug 2007

Realizing Live Sequence Charts In System Verilog, Hai H. Wang, Shengchao Qin, Jun Sun, Jin Song Dong

Research Collection School Of Computing and Information Systems

The design of an embedded control system starts with an investigation of properties and behaviors of the process evolving within its environment, and an analysis of the requirement for its safety performance. In early stages, system requirements are often specied as scenarios of behavior using sequence charts for different use cases. This specication must be precise, intuitive and expressive enough to capture different aspects of embedded control systems. As a rather rich and useful extension to the classical message sequence charts, Live Sequence Charts (LSC), which provide a rich collection of constructs for specifying both possible and mandatory behaviors, are …

Go to article

Century: Automated Aspects Of Patient Care, Marion Blount, John Davis, Maria Ebling, Ji Hyun Kim, Kyun Hyun Kim, Kang Yoon Lee, Archan Misra, Se Hun Park, Daby Sow, Young Ju Tak, Min Wang, Karen Witting Aug 2007

Century: Automated Aspects Of Patient Care, Marion Blount, John Davis, Maria Ebling, Ji Hyun Kim, Kyun Hyun Kim, Kang Yoon Lee, Archan Misra, Se Hun Park, Daby Sow, Young Ju Tak, Min Wang, Karen Witting

Research Collection School Of Computing and Information Systems

Remote health monitoring affords the possibility of improving the quality of health care by enabling relatively inexpensive out-patient care. However, remote health monitoring raises new a problem: the potential for data explosion in health care systems. To address this problem, the remote health monitoring systems must be integrated with analysis tools that provide automated trend analysis and event detection in real time. In this paper, we propose an overview of Century, an extensible framework for analysis of large numbers of remote sensor-based medical data streams.

Go to article

Maximizing Broadcast And Multicast Traffic Load Through Link-Rate Diversity In Wireless Mesh Networks, Chun Tung Chou, Bao Hua Liu, Archan Misra Jun 2007

Maximizing Broadcast And Multicast Traffic Load Through Link-Rate Diversity In Wireless Mesh Networks, Chun Tung Chou, Bao Hua Liu, Archan Misra

Research Collection School Of Computing and Information Systems

This paper studies some of the fundamental challenges and opportunities associated with the network-layer broadcast and multicast in a multihop multirate wireless mesh network (WMN). In particular, we focus on exploiting the ability of nodes to perform link-layer broadcasts at different rates (with correspondingly different coverage areas). We first show how, in the broadcast wireless medium, the available capacity at a mesh node for a multicast transmission is not just a function of the aggregate pre-existing traffic load of other interfering nodes, but intricately coupled to the actual (sender, receiver) set and the link-layer rate of each individual transmission. We …

Go to article

A Time-And-Value Centric Provenance Model And Architecture For Medical Event Streams, Marion Bllount, John Davis, Archan Misra, Daby Sow, Min Wang Jun 2007

A Time-And-Value Centric Provenance Model And Architecture For Medical Event Streams, Marion Bllount, John Davis, Archan Misra, Daby Sow, Min Wang

Research Collection School Of Computing and Information Systems

Provenance becomes a critical requirement for healthcare IT infrastructures, especially when pervasive biomedical sensors act as a source of raw medical streams for large-scale, automated clinical decision support systems. Medical and legal requirements will make it obligatory for such systems to answer queries regarding the underlying data samples from which output alerts are derived, the IDs of the processing components used and the privileges of the individuals and software components accessing the medical data. Unfortunately, existing models of either annotation or process based provenance are designed for transaction-oriented systems and do not satisfy the unique requirements for systems processing high-volume, …

Go to article

Simplifying Cyber Foraging For Mobile Devices, Rajesh Krishna Balan, Darren Gergle, Mahadev Satyanarayanan, James Herbsleb Jun 2007

Simplifying Cyber Foraging For Mobile Devices, Rajesh Krishna Balan, Darren Gergle, Mahadev Satyanarayanan, James Herbsleb

Research Collection School Of Computing and Information Systems

Cyber foraging is the transient and opportunistic use of compute servers by mobile devices. The short market life of such devices makes rapid modification of applications for remote execution an important problem. We describe a solution that combines a "little language" for cyber foraging with an adaptive runtime system. We report results from a user study showing that even novice developers are able to successfully modify large, unfamiliar applications in just a few hours. We also show that the quality of novice-modified and expert-modified applications are comparable in most cases.

Go to article

Deckard: Scalable And Accurate Tree-Based Detection Of Code Clones, Lingxiao Jiang, Ghassan Misherghi, Zhendong Su, Stephane Glondu May 2007

Deckard: Scalable And Accurate Tree-Based Detection Of Code Clones, Lingxiao Jiang, Ghassan Misherghi, Zhendong Su, Stephane Glondu

Research Collection School Of Computing and Information Systems

Detecting code clones has many software engineering applications. Existing approaches either do not scale to large code bases or are not robust against minor code modifications. In this paper, we present an efficient algorithm for identifying similar subtrees and apply it to tree representations of source code. Our algorithm is based on a novel characterization of subtrees with numerical vectors in the Euclidean Rn and an efficient algorithm to cluster these vectors w.r.t. the Euclidean distance metric. Subtrees with vectors in one cluster are considered similar. We have implemented our tree similarity algorithm as a clone detection tool called DECKARD …

Go to article

Experiences With Tracking The Effects Of Changing Requirements On Morphbank: A Web-Based Bioinformatics Application, Subhajit Datta, Robert Van Engelen, David Gaitros, Neelima Jammigumpula Mar 2007

Experiences With Tracking The Effects Of Changing Requirements On Morphbank: A Web-Based Bioinformatics Application, Subhajit Datta, Robert Van Engelen, David Gaitros, Neelima Jammigumpula

Research Collection School Of Computing and Information Systems

In this paper, we present a case study of applying the metrics Mutation Index, Component Set, Dependency Index on Morphbank- a web based bioinformatics application - to track the effects of changing requirements on a software system and suggest design modifications to mitigate such impact. Morphbank is "an open web repository of biological images documenting specimen-based research in comparative anatomy, morphological phylogenetics, taxonomy and related fields focused on increasing our knowledge about biodiversity". This paper discusses the context of the case study, analyzes the results, highlights observations and learning, and mentions directions of future work.

Go to article

Businessfinder: Harnessing Presence To Enable Live Yellow Pages For Small, Medium And Micro Mobile Businesses, D. Chakraborty, K. Dasgupta, S. Mittal, Archan Misra, C. Oberle, A. Gupta, E. Newmark Jan 2007

Businessfinder: Harnessing Presence To Enable Live Yellow Pages For Small, Medium And Micro Mobile Businesses, D. Chakraborty, K. Dasgupta, S. Mittal, Archan Misra, C. Oberle, A. Gupta, E. Newmark

Research Collection School Of Computing and Information Systems

Applications leveraging network presence in next-generation cellular networks have so far focused on subscription queries, where "presence" information is extracted from specific devices and sent to entities who have subscribed to such presence information. In this article we present BusinessFinder, a service that leverages the underlying cellular presence substrate to provide efficient, on-demand, context-aware matching of customer requests to nomadic micro businesses as well as small and medium businesses having a mobile workforce. Presence, in the context of BusinessFinder, is not simply limited to phone location and device status, but also encompasses dynamic attributes of vendors (both "mobile" and "static"), …

Go to article