Computer Sciences Commons^™

Profile-Guided Program Simplification For Effective Testing And Analysis, Lingxiao Jiang, Zhendong Su

Research Collection School Of Computing and Information Systems

Many testing and analysis techniques have been developed for inhouse use. Although they are effective at discovering defects before a program is deployed, these techniques are often limited due to the complexity of real-world code and thus miss program faults. It will be the users of the program who eventually experience failures caused by the undetected faults. To take advantage of the large number of program runs carried by the users, recent work has proposed techniques to collect execution profiles from the users for developers to perform post-deployment failure analysis. However, in order to protect users' privacy and to reduce …

An Exploratory Overview Of Teaching Computer Game Development, Mario Guimaraes, Meg C. Murray

Faculty Articles

The computer game industry has exploded reaching sales of several billion dollars a year and, consequently, a majority of college students are familiar with the gaming environment. In fact, videogame development has been cited as one way to motivate students to explore the world of Computer Science. However, most videogames are extremely complex computer programs created by a team of developers including programmers and graphic artists and represent thousands of hours of work. Fortunately there are software tools available that provide a way for simple computer games to be created fairly easily using a building block approach. This paper discusses …

On The Assessment Of Pointcut Design In Evolving Aspect-Oriented Software, Raffi Khatchadourian, Phil Greenwood, Awais Rashid

Publications and Research

No abstract provided.

A Study Of Early Stage Game Design And Prototyping, Brien Colwell, Richard C. Davis, James A. Landay

Research Collection School Of Computing and Information Systems

Computer games and simulations can be valuable teaching and communication tools, and they are a powerful form of self-expression. Unfortunately, creating games requires programming, and programming requires time and skill. Some tools facilitate game creation to motivate novice programmers, but programming is still necessary. Other systems require less programming, but they are narrowly focused. To enable faster, simpler, and more expressive tools for professionals and amateurs, we have explored the processes and tools used in the early stages of game and simulation design. Interviews with educators clarified the uses of simulations in the classroom, while interviews with professional game designers …

Specification Mining Of Symbolic Scenario-Based Models, David Lo, Shahar Maoz

Research Collection School Of Computing and Information Systems

Many dynamic analysis approaches to specification mining, which extract behavioral models from execution traces, do not consider object identities. This limits their power when used to analyze traces of general object oriented programs. In this work we present a novel specification mining approach that considers object identities, and, moreover, generalizes from specifications involving concrete objects to their symbolic class-level abstractions. Our approach uses data mining methods to extract significant scenario-based specifications in the form of Damm and Harel's live sequence charts (LSC), a formal and expressive extension of classic sequence diagrams. We guarantee that all mined symbolic LSCs are significant …

Specifying And Verifying Sensor Networks: An Experiment Of Formal Methods, Jin Song Dong, Jing Sun, Jun Sun, Kenji Taguchi, Xian Zhang

Research Collection School Of Computing and Information Systems

With the development of sensor technology and electronic miniaturization, wireless sensor networks have shown a wide range of promising applications as well as challenges. Early stage sensor network analysis is critical, which allows us to reveal design errors before sensor deployment. Due to their distinguishable features, system specification and verification of sensor networks are highly non-trivial tasks. On the other hand, numerous formal theories and analysis tools have been developed in formal methods community, which may offer a systematic method for formal analysis of sensor networks. This paper presents our attempt on applying formal methods to sensor network specification/verification. An …

Resource-Aware Video Multicasting Via Access Gateways In Wireless Mesh Networks, Wanqing Tu, Cormac J. Sreenan, Chun Tung Chou, Archan Misra

Research Collection School Of Computing and Information Systems

This paper studies video multicasting in large scale areas using wireless mesh networks. The focus is on the use of Internet access gateways that allow a choice of alternative routes to avoid potentially lengthy multi-hop wireless paths with low capacity. A set of heuristic-based algorithms are described that together aim to maximize network capacity: the two-tier integrated architecture algorithm, the weighted gateway uploading algorithm, the link-controlled routing tree algorithm, and the alternative channel assignment algorithm. These algorithms use different approaches to arrange multicast group members into a clustered and two-tier integrated architecture in which network protocols can make use of …

Specifying And Verifying Event-Based Fairness Enhanced Systems, Jun Sun, Yang Liu, Jin Song Dong, Hai H. Wang

Research Collection School Of Computing and Information Systems

Liveness/Fairness plays an important role in software specification, verification and development. Existing event-based compositional models are safety-centric. In this paper, we describe a framework for systematically specifying and verifying event-based systems under fairness assumptions. We introduce different event annotations to associate fairness constraints with individual events. Fairness annotated events can be used to embed liveness/fairness assumptions in event-based models flexibly and naturally. We show that state-of-the-art verification algorithms can be extended to verify models under fairness assumptions, with little computational overhead. We further improve the algorithm by other model checking techniques like partial order reduction. A toolset named Pat has …

Model Checking Csp Revisited: Introducing A Process Analysis Toolkit, Jun Sun, Yang Liu, Jin Song Dong

Research Collection School Of Computing and Information Systems

FDR, initially introduced decades ago, is the de facto analyzer for Communicating Sequential Processes (CSP). Model checking techniques have been evolved rapidly since then. This paper describes PAT, i.e., a process analysis toolkit which complements FDR in several aspects. PAT is designed to analyze event-based compositional system models specified using CSP as well as shared variables and asynchronous message passing. It supports automated refinement checking, model checking of LTL extended with events, etc. In this paper, we highlight how partial order reduction is applied to improve refinement checking in PAT. Experiment results show that PAT outperforms FDR in some cases.

Link Layer Multicast Using Smart Antennas: No Client Left Behind, Souvik Sen, Jie Xiong, Rahul Ghosh, Romit Roy Choudhury

Research Collection School Of Computing and Information Systems

Wireless link layer multicast is an important service primitive for emerging applications, such as live video, streaming audio, and other content telecasts. The broadcast nature of the wireless channel is amenable to multicast because a single packet transmission may be received by all clients in the multicast group. However, in view of diverse channel conditions at different clients, the rate of such a transmission is bottlenecked by the rate of the weakest client. Multicast throughput degrades severely. Attempts to increase the data rate result in lower reliability and higher unfairness. This paper utilizes smart beamforming antennas to improve multicast performance …

Unifying Framework For Building Social Computing Applications, Renato Costa, Luiz Fernando Capretz

Electrical and Computer Engineering Publications

There have been a number of frameworks and models developed to

support different aspects of social computing. Some were developed to deal

with online interaction through the application of computer-mediated communications

tools, whereas others such as social network analyses and reputation

systems were more specific in their focus. While these methodologies are interrelated,

current social computing research has dealt with them as separate aspects.

This paper presents a comprehensive framework for social computing

that aims at integrating all these three aspects into a unified model so that discovery

and exploration of community members are not only made possible, but

also …

Rejuvenate Pointcut: A Tool For Pointcut Expression Recovery In Evolving Aspect-Oriented Software, Raffi Khatchadourian, Awais Rashid

Publications and Research

Aspect-oriented programming (AOP) strives to localize the scattered and tangled implementations of crosscutting concerns (CCCs) by allowing developers to declare that certain actions (advice) should be taken at specific points (join points) during the execution of software where a CCC (an aspect) is applicable. However, it is non-trivial to construct optimal pointcut expressions (a collection of join points) that capture the true intentions of the programmer and, upon evolution, maintain these intentions. We demonstrate an AspectJ source-level inferencing tool called rejuvenate pointcut which helps developers maintain pointcut expressions over the lifetime of a software product. A key insight into the …

Software Nightmares, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

To err is human, but to really foul things up, you need a computer. So states the remarkably insightful Murphy’s Law. And nowhere else does this ring truer than in our financial workplace. After all, it is the financial sector that drove the rapid progress in the computing industry – which is why the first computing giant had the word “business” in its name. The financial industry keeps up with the developments in the computer industry for one simple reason. Stronger computers and smarter programs mean more money — a concept we readily grasp. As we use the latest and …

A Generic Approach And Framework For Managing Complex Information, Essam Mansour

Doctoral

Several application domains, such as healthcare, incorporate domain knowledge into their day-to-day activities to standardise and enhance their performance. Such incorporation produces complex information, which contains two main clusters (active and passive) of information that have internal connections between them. The active cluster determines the recommended procedure that should be taken as a reaction to specific situations. The passive cluster determines the information that describes these situations and other descriptive information plus the execution history of the complex information. In the healthcare domain, a medical patient plan is an example for complex information produced during the disease management activity from …

Pointcut Rejuvenation: Recovering Pointcut Expressions In Evolving Aspect-Oriented Software, Raffi Khatchadourian, Phil Greenwood, Awais Rashid, Guoqing Harry Xu

Publications and Research

Pointcut fragility is a well-documented problem in Aspect-Oriented Programming; changes to the base-code can lead to join points incorrectly falling in or out of the scope of pointcuts. In this paper, we present an automated approach which limits fragility problems by providing mechanical assistance in pointcut maintenance. The approach is based on harnessing arbitrarily deep structural commonalities between program elements corresponding to join points selected by a pointcut. The extracted patterns are then applied to later versions to offer suggestions of new join points that may require inclusion. To illustrate that the motivation behind our proposal is well-founded, we first …

Impacts Of Social Network Structure On Knowledge Sharing In Open Source Software Development Teams, Y. Long, Keng Siau

Research Collection School Of Computing and Information Systems

The study examines the relationship between social network structure and knowledge sharing in Open Source Software (OSS) development teams. One hundred and fifty projects were selected from SourceForge.net using stratified sampling. Social network structure was measured by two indices: degree of centralization and core/periphery fitness. Knowledge sharing was measured from two aspects: the quality of knowledge sharing that is indicated by the helpfulness of messages and the quantity of knowledge sharing that is indicated by the number of messages. The results show that social network structure significantly affects the quantity of knowledge sharing. However, social network structure does not influence …

Mining Patterns And Rules For Software Specification Discovery, David Lo, Siau-Cheng Khoo

Research Collection School Of Computing and Information Systems

Software specifications are often lacking, incomplete and outdated in the industry. Lack and incomplete specifications cause various software engineering problems. Studies have shown that program comprehension takes up to 45% of software development costs. One of the root causes of the high cost is the lack-of documented specification. Also, outdated and incomplete specification might potentially cause bugs and compatibility issues. In this paper, we describe novel data mining techniques to mine or reverse engineer these specifications from the pool of software engineering data. A large amount of software data is available for analysis. One form of software data is program …

Hierarchical Inter-Object Traces For Specification Mining, David Lo, Shahar Maoz

Research Collection School Of Computing and Information Systems

Major challenges of dynamic analysis approaches to specification mining include scalability over long traces as well as comprehensibility and expressivity of results. We present a novel use of object hierarchies over inter-object traces as an abstraction/refinement mechanism enabling scalable, incremental, top-down mining of scenario-based specifications.

Perspective Models: A Mechanism For Achieving Interoperability Among Expressive, Personalized Domain Views, Kym J. Pohl, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

Accurate and expressive representation of the subject matter over which a context-oriented, decision-support system operates is fundamental to the effectiveness and longevity of the resulting solution. Often taking the form of an ontology, such extensive representational models, by their very nature, are rich in relationships and both coarse and fine-grained objects. It is, however, these qualities enabling rich expression that can significantly increase both the complexity of developing against these models as well as the potential for incurring undesirable performance issues. Further, due to the typically detail-oriented usage inherent in the software-based users (i.e., reasoning agents, etc.) of these models, …

Similarity Assessment Techniques, Michael A. Zang, Adam Gray, Michael Hobbs, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

This paper serves as a layman’s introduction to similarity assessment techniques, their distinction from contemporary computing paradigms, and their real-world applications. The following content derives from the experience gained by the authors in applying similarity assessment techniques to resolve the real-world problems of CDM customers, in particular those faced by the United States Transportation Command (USTRANSCOM).

Pre-Conference Proceedings Of The Focus Symposium On Intelligent Software Tools And Services, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

No abstract provided.

Icodes: A Multi-Agent System In Practice, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

This paper describes the Integrated Computerized Deployment System (ICODES) from both an architectural and evolutionary vantage point.

First, ICODES is a logistic software application of ship load-planning tools that utilizes intelligent software agents in a human-computer collaborative mode. As an example of a new generation of intelligent military decision-support systems, ICODES includes expert agents with automatic reasoning and analysis capabilities. This is made possible by an internal virtual representation of the load-planning environment, in terms of conveyance and cargo characteristics and the complex relationships that constitute the context within which load-planning operations are performed. ICODES agents monitor the principal determinants …

Challenging Computer Software Frontiers And The Human Resistance To Change, Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

This paper examines the driving and opposing forces that are governing the current paradigm shift from a data-processing information technology environment without software intelligence to an information-centric environment in which data changes are automatically interpreted within the context of the application domain. The driving forces are related to the large quantity of data and the complexity of networked systems that both call for software intelligence. The opposing forces are non-technical and due to the natural human resistance to change.

Based on this background the paper describes current information-centric technology, proposes a vision of intelligent software system capabilities, and identifies four …

A Model Of Open Source Software-Based Product Line Development, Luiz Fernando Capretz, Faheem Ahmed, Mohammad Ali Babar

Electrical and Computer Engineering Publications

Software Product Line (SPL) and Open Source Software (OSS) have emerged as successful modes of developing software. There is an increased interest in developing suitable approaches for combining the promised advantages of SPL andOSS. Researchers and practitioners have been emphasizing the need of exploiting the ever growing repositories ofOSScomponents for developing SPLs. However, there is no conceptual model for guiding the process of developing OSS-based SPLs. In this paper, we propose a model for developing software product line using open source software. This paper identifies and elaborates the essential phases and activities of the proposed model of developing OSS-based SPLs. …

Fuzzy Inference System For Software Product Family Process Evaluation, Faheem Ahmed, Luiz Fernando Capretz, Jagath Samarabandu

Electrical and Computer Engineering Publications

When developing multiple products within a common application domain, systematic use of a software product family process can yield increased productivity in cost, quality, effort and schedule. Such a process provides the means for the reuse of software assets which can considerably reduce the development time and the cost of software products. A comprehensive strategy for the evaluating the maturity of a software product family process is needed due to growing popularity of this concept in the software industry. In this paper, we propose a five-level maturity scale for software product family process. We also present a fuzzy inference system …

Mining Temporal Rules For Software Maintenance, David Lo, Siau-Cheng Khoo, Chao Liu

Research Collection School Of Computing and Information Systems

Software evolution incurs difficulties in program comprehension and software verification, and hence it increases the cost of software maintenance. In this study, we propose a novel technique to mine from program execution traces a sound and complete set of statistically significant temporal rules of arbitrary lengths. The extracted temporal rules reveal invariants that the program observes, and will consequently guide developers to understand the program behaviors, and facilitate all downstream applications such as verification and debugging. Different from previous studies that were restricted to mining two-event rules (e.g., (lock) →(unlock)), our algorithm discovers rules of arbitrary lengths. In order to …

User Guidance Of Resource-Adaptive Systems, João Pedro Sousa, Rajesh Krishna Balan, Vahe Poladian, David Garlan, Mahadev Satyanarayanan

Research Collection School Of Computing and Information Systems

This paper presents a framework for engineering resource-adaptive software systems targeted at small mobile devices. The proposed framework empowers users to control tradeoffs among a rich set of ervicespecific aspects of quality of service. After motivating the problem, the paper proposes a model for capturing user preferences with respect to quality of service, and illustrates prototype user interfaces to elicit such models. The paper then describes the extensions and integration work made to accommodate the proposed framework on top of an existing software infrastructure for ubiquitous computing. The research question addressed here is the feasibility of coordinating resource allocation and …

Bounded Model Checking Of Compositional Processes, Jun Sun, Yang Liu, Jin Song Dong, Jing Sun

Research Collection School Of Computing and Information Systems

Verification techniques like SAT-based bounded model checking have been successfully applied to a variety of system models. Applying bounded model checking to compositional process algebras is, however, not a trivial task. One challenge is that the number of system states for process algebra models is not statically known, whereas exploring the full state space is computationally expensive. This paper presents a compositional encoding of hierarchical processes as SAT problems and then applies state-of-the-art SAT solvers for bounded model checking. The encoding avoids exploring the full state space for complex systems so as to deal with state space explosion. We developed …

Searching Correlated Objects In A Long Sequence, Ken C. K. Lee, Wang-Chien Lee, Donna Peuquet, Baihua Zheng

Research Collection School Of Computing and Information Systems

Sequence, widely appearing in various applications (e.g. event logs, text documents, etc) is an ordered list of objects. Exploring correlated objects in a sequence can provide useful knowledge among the objects, e.g., event causality in event log and word phrases in documents. In this paper, we introduce correlation query that finds correlated pairs of objects often appearing closely to each other in a given sequence. A correlation query is specified by two control parameters, distance bound, the requirement of object closeness, and correlation threshold, the minimum requirement of correlation strength of result pairs. Instead of processing the query by scanning …

Mining Past-Time Temporal Rules From Execution Traces, David Lo, Siau-Cheng Khoo, Chao Liu

Research Collection School Of Computing and Information Systems

Specification mining is a process of extracting specifications, often from program execution traces. These specifications can in turn be used to aid program understanding, monitoring and verification. There are a number of dynamic-analysis-based specification mining tools in the literature, however none so far extract past time temporal expressions in the form of rules stating: whenever a series of events occurs, previously another series of events has happened. Rules of this format are commonly found in practice and useful for various purposes. Most rule-based specification mining tools only mine future-time temporal expression. Many past-time temporal rules like whenever a resource is …