Computer Sciences Commons^™

Network Structure Of Social Coding In Github, Ferdian Thung, Tegawende F. Bissyande, David Lo, Lingxiao Jiang

Research Collection School Of Computing and Information Systems

Social coding enables a different experience of software development as the activities and interests of one developer are easily advertized to other developers. Developers can thus track the activities relevant to various projects in one umbrella site. Such a major change in collaborative software development makes an investigation of networkings on social coding sites valuable. Furthermore, project hosting platforms promoting this development paradigm have been thriving, among which GitHub has arguably gained the most momentum. In this paper, we contribute to the body of knowledge on social coding by investigating the network structure of social coding in GitHub. We collect …

Predicting Project Outcome Leveraging Socio-Technical Network Patterns, Didi Surian, Yuan Tian, David Lo, Hong Cheng, Ee Peng Lim

Research Collection School Of Computing and Information Systems

There are many software projects started daily, some are successful, while others are not. Successful projects get completed, are used by many people, and bring benefits to users. Failed projects do not bring similar benefits. In this work, we are interested in developing an effective machine learning solution that predicts project outcome (i.e., success or failures) from developer socio-technical network. To do so, we investigate successful and failed projects to find factors that differentiate the two. We analyze the socio-technical aspect of the software development process by focusing at the people that contribute to these projects and the interactions among …

Empirical Evaluation Of Bug Linking, Tegawende F. Bissyande, Ferdian Thung, Shaowei Wang, David Lo, Lingxiao Jiang, Laurent Reveillere

Research Collection School Of Computing and Information Systems

To collect software bugs found by users, development teams often setup bug trackers using systems such as Bugzilla. Developers would then fix some of the bugs and commit corresponding code changes into version control systems such as svn or git. Unfortunately, the links between bug reports and code changes are missing for many software projects as the bug tracking and version control systems are often maintained separately. Yet, linking bug reports to fix commits is important as it could shed light into the nature of bug fixing processes and expose patterns in software management. Bug linking solutions, such as ReLink, …

Understanding Widespread Changes: A Taxonomic Study, Shaowei Wang, David Lo, Lingxiao Jiang

Research Collection School Of Computing and Information Systems

No abstract provided.

Infrastructure-Assisted Smartphone-Based Adl Recognition In Multi-Inhabitant Smart Environments, Nirmalya Roy, Archan Misra, Diane Cook

Research Collection School Of Computing and Information Systems

We propose a hybrid approach for recognizing complex Activities of Daily Living that lie between the two extremes of intensive use of body-worn sensors and the use of infrastructural sensors. Our approach harnesses the power of infrastructural sensors (e.g., motion sensors) to provide additional `hidden' context (e.g., room-level location) of an individual and combines this context with smartphone-based sensing of micro-level postural/locomotive states. The major novelty is our focus on multi-inhabitant environments, where we show how spatiotemporal constraints can be used to significantly improve the accuracy and computational overhead of traditional coupled-HMM based approaches. Experimental results on a smart home …

Understanding Widespread Changes: A Taxonomic Study, Shaowei Wang, David Lo, Lingxiao Jiang

Research Collection School Of Computing and Information Systems

Many active research studies in software engineering, such as detection of recurring bug fixes, detection of copyand- paste bugs, and automated program transformation tools, are motivated by the assumption that many code changes (e.g., changing an identifier name) in software systems are widespread to many locations and are similar to one another. However, there is no study so far that actually analyzes widespread changes in software systems. Understanding the nature of widespread changes could empirically support the assumption, which provides insight to improve the research studies and related tools. Our study in this paper addresses such a need. We propose …

Adoption Of Software Testing In Open Source Projects: A Preliminary Study On 50,000 Projects, Pavneet Singh Kochhar, Tegawende F. Bissyande, David Lo, Lingxiao Jiang

Research Collection School Of Computing and Information Systems

In software engineering, testing is a crucial activity that is designed to ensure the quality of program code. For this activity, development teams spend substantial resources constructing test cases to thoroughly assess the correctness of software functionality. What is however the proportion of open source projects that include test cases? What kind of projects are more likely to include test cases? In this study, we explore 50,000 projects and investigate the correlation between the presence of test cases and various project development characteristics, including the lines of code and the size of development teams.

An Empirical Study On Developer Interactions In Stackoverflow, Shaowei Wang, David Lo, Lingxiao Jiang

Research Collection School Of Computing and Information Systems

StackOverflow provides a popular platform where developers post and answer questions. Recently, Treude et al. manually label 385 questions in StackOverflow and group them into 10 categories based on their contents. They also analyze how tags are used in StackOverflow. In this study, we extend their work to obtain a deeper understanding on how developers interact with one another on such a question and answer web site. First, we analyze the distributions of developers who ask and answer questions. We also investigate if there is a segregation of the StackOverflow community into questioners and answerers. We also perform automated text …

Improving Webide Through Delightful Design And Gamification, Michael Hilton

Master's Theses

WebIDE is a web-based online learning environment. WebIDE has been used

successfully to teach CS0 and CS1 students Java and C concepts and software

engineering best practices, specically Test Driven Development. Previous Web-

IDE development has concentrated on developing functionality. The main goal

of this eort is to improve two non-functional aspects of WebIDE. The rst is to

design a more delightful user interface. The second is to add a scoring mecha-

nism that encourages students to develop best practices. The scoring mechanism

rewards students who answer the question correctly on the rst attempt, dis-

couraging them from spamming the …

Combining Crowdsourcing And Google Street View To Identify Street-Level Accessibility Problems, Kotaro Hara, Victoria Le, Jon Froehlich

Research Collection School Of Computing and Information Systems

Jon FroehlichAbstractPoorly maintained sidewalks, missing curb ramps, and other obstacles pose considerable accessibility challenges; however, there are currently few, if any, mechanisms to determine accessible areas of a city a priori. In this paper, we investigate the feasibility of using untrained crowd workers from Amazon Mechanical Turk (turkers) to find, label, and assess sidewalk accessibility problems in Google Street View imagery. We report on two studies: Study 1 examines the feasibility of this labeling task with six dedicated labelers including three wheelchair users; Study 2 investigates the comparative performance of turkers. In all, we collected 13,379 labels and 19,189 verification …

Authscan: Automatic Extraction Of Web Authentication Protocols From Implementations, Guangdong Bai, Jike Lei, Guozhu Meng, Sai Sathyanarayan Venkatraman, Prateek Saxena, Jun Sun, Yang Liu, Jin Song Dong

Research Collection School Of Computing and Information Systems

Ideally, security protocol implementations should be formally verified before they are deployed. However, this is not true in practice. Numerous high-profile vulnerabilities have been found in web authentication protocol implementations, especially in single-sign on (SSO) protocols implementations recently. Much of the prior work on authentication protocol verification has focused on theoretical foundations and building scalable verification tools for checking manually-crafted specifications [17, 18, 44]. In this paper, we address a complementary problem of automatically extracting specifications from implementations. We propose AUTHSCAN, an end-to-end platform to automatically recover authentication protocol specifications from their implementations. AUTHSCAN finds a total of 7 security …

Mutual Assessment In The Social Programmer Ecosystem: An Empirical Investigation Of Developer Profile Aggregators, Leif Singer, Fernando Figueira Filho, Brendan Cleary, Christoph Treude, Margaret-Anne Storey, Kurt Schneider

Research Collection School Of Computing and Information Systems

The multitude of social media channels that programmers can use to participate in software development has given rise to online developer profiles that aggregate activity across many services. Studying members of such developer profile aggregators, we found an ecosystem that revolves around the social programmer. Developers are assessing each other to evaluate whether other developers are interesting, worth following, or worth collaborating with. They are self-conscious about being assessed, and thus manage their public images. They value passion for software development, new technologies, and learning. Some recruiters participate in the ecosystem and use it to find candidates for hiring; other …

A Utp Semantics For Communicating Processes With Shared Variables, Ling Shi, Yongxin Zhao, Yang Liu, Jun Sun, Jin Song Dong, Shengchao Qin

Research Collection School Of Computing and Information Systems

CSP# (Communicating Sequential Programs) is a modelling language designed for specifying concurrent systems by integrating CSP-like compositional operators with sequential programs updating shared variables. In this paper, we define an observation-oriented denotational semantics in an open environment for the CSP# language based on the UTP framework. To deal with shared variables, we lift traditional event-based traces into hybrid traces which consist of event-state pairs for recording process behaviours. We also define refinement to check process equivalence and present a set of algebraic laws which are established based on our denotational semantics. Our approach thus provides a rigorous means for reasoning …

Verification Of Functional And Non-Functional Requirements Of Web Service Composition, Manman Chen, Tian Huat Tan, Jun Sun, Yang Liu, Jun Pang, Xiaohong Li

Research Collection School Of Computing and Information Systems

Web services have emerged as an important technology nowadays. There are two kinds of requirements that are crucial to web service composition, which are functional and non-functional requirements. Functional requirements focus on functionality of the composed service, e.g., given a booking service, an example of functional requirements is that a flight ticket with price higher than $2000 will never be purchased. Non-functional requirements are concerned with the quality of service (QoS), e.g., an example of the booking service’s non-functional requirements is that the service will respond to the user within 5 seconds. Non-functional requirements are important to web service composition, …

Improving Model Checking Stateful Timed Csp With Non-Zenoness Through Clock-Symmetry Reduction, Yuanjie Si, Jun Sun, Yang Liu, Ting Wang

Research Collection School Of Computing and Information Systems

Real-time system verification must deal with a special notion of ‘fairness’, i.e., clocks must always be able to progress. A system run which prevents clocks from progressing unboundedly is known as Zeno. Zeno runs are infeasible in reality and thus must be pruned during system verification. Though zone abstraction is an effective technique for model checking real-time systems, it is known that zone graphs (e.g., those generated from Timed Automata models) are too abstract to directly infer time progress and hence non-Zenoness. As a result, model checking with non-Zenoness (i.e., existence of a non-Zeno counterexample) based on zone graphs only …

Vtrust: A Formal Modeling And Verification Framework For Virtualization Systems, Jianan Hao, Yang Liu, Wentong Cai, Guangdong Bai, Jun Sun

Research Collection School Of Computing and Information Systems

Virtualization is widely used for critical services like Cloud computing. It is desirable to formally verify virtualization systems. However, the complexity of the virtualization system makes the formal analysis a difficult task, e.g., sophisticated programs to manipulate low-level technologies, paged memory management, memory mapped I/O and trusted computing. In this paper, we propose a formal framework, vTRUST, to formally describe virtualization systems with a carefully designed abstraction. vTRUST includes a library to model configurable hardware components and technologies commonly used in virtualization. The system designer can thus verify virtualization systems on critical properties (e.g., confidentiality, verifiability, isolation and PCR consistency) …

Verifying Linearizability Via Optimized Refinement Checking, Yang Liu, Wei Chen, Yanhong A. Liu, Jun Sun, Shao Jie Zhang, Jin Song Dong Dong

Research Collection School Of Computing and Information Systems

Linearizability is an important correctness criterion for implementations of concurrent objects. Automatic checking of linearizability is challenging because it requires checking that: 1) All executions of concurrent operations are serializable, and 2) the serialized executions are correct with respect to the sequential semantics. In this work, we describe a method to automatically check linearizability based on refinement relations from abstract specifications to concrete implementations. The method does not require that linearization points in the implementations be given, which is often difficult or impossible. However, the method takes advantage of linearization points if they are given. The method is based on …

Modeling And Verifying Hierarchical Real-Time Systems Using Stateful Timed Csp, Jun Sun, Yang Liu, Jin Song Dong, Yan Liu, Ling Shi, Étienne André

Research Collection School Of Computing and Information Systems

Modeling and verifying complex real-time systems are challenging research problems. The de facto approach is based on Timed Automata, which are finite state automata equipped with clock variables. Timed Automata are deficient in modeling hierarchical complex systems. In this work, we propose a language called Stateful Timed CSP and an automated approach for verifying Stateful Timed CSP models. Stateful Timed CSP is based on Timed CSP and is capable of specifying hierarchical real-time systems. Through dynamic zone abstraction, finite-state zone graphs can be generated automatically from Stateful Timed CSP models, which are subject to model checking. Like Timed Automata, Stateful …

Raising The Game: Applying Theory And Analytics To Real-World Threats, Singapore Management University

Perspectives@SMU

Safety and security are, on many levels, essential priorities for governments, businesses and individuals. While an increase of defence and security budgets may bring some assurance of peaceful times to come, it seems the world has no lack of insane perpetrators who can still somehow evade, breach, ambush, assail and attack as they please. Enter the “Bayesian Stackelberg Game”, a game theory model that can, and has been applied rather successfully to the allocation of security resources in the United States by Prof Milind Tambe, University of Southern California.

Special Issue On Medical Simulation, Michel Audette, Hanif M. Ladak

Computational Modeling & Simulation Engineering Faculty Publications

We would like to welcome you to this Special Issue on Medical Simulation, the first of its kind not only for SIMULATION: Transactions of The Society for Modeling and Simulation International, but for any technical journal. Our respective backgrounds are an indication of the technical and clinical breadth of medical simulation, as we approach the subject as primarily medical image analysis and biomechanics experts respectively, each with a variety of clinical interests spanning virtual reality (VR)–based neuro-, orthopedic and ear-nose-and-throat surgery. Moreover, we believe that the breadth of the papers that comprise this issue reflects an even broader perspective. After …

Impact Of Varied Low Resolution Phantoms On Intensity Modulated Proton Therapy Dose Distributions, Aarohi Shyam Padhye

Theses Digitization Project

The primary purpose of this thesis is to discuss the usefulness of image segmentation techniques in creating accurate proton dose distribution plans. The calculation of the proton dose distribution has to take into account the material (tissue, bone, brain) in the treatment area of the patients body.

Stereotactic Localization And Targeting Accuracy For Experimental Proton Radiosurgery, Yin Chen

Theses Digitization Project

The purpose of this study was to improve an existing experimental proton radiosurgery system at Loma Linda University Medical Center to reach sub-millimeter accuracy before proton radiosurgery with narrow beams can be used in a clinical trial. Protons, different from photons (i.e., x-rays or gamma rays), are charged with particles that slow down in matter and release a burst of energy near the end of their range (maximum depth of penetration), which is called the Bragg peak, named after the physicist William Henry Bragg who discovered it in 1903. Photon beams deliver most doses over a large area near the …

3d Face Animation With Opengl Es: An Android Application, Ihab Mohamad Zbib

Theses Digitization Project

Mobile applications have become ubiquitious with the increase in the popularity and computational power of mobile devices. They can now support rich multimedia user interactions. This project consists of the design and implementaiton of an Android application that renders and animates a three-dimensional model of a human head. The test is synthesized using an Android Text-to-Speech (TTS) engine. The application successfully implements a novel solution for the animated speech synchronization and opens the door for further work in the field of interactive animation. The project can be extended to become an interface for virtual remote communication or animated text messaging.

Fiducial-Free Alignment Verification Techniques For Intracranial Radiosurgery, Kenneth Matthew Williams

Theses Digitization Project

This thesis serves as the basis for a method using image registration to automate patient alignment in an effort to eliminate the dependency on the fiducial markers as well as improve the accuracy efficiency of the alignment process. Proton beams are an external beam modality of radiation therapy that can be used effectively for radiosurgical applications due to the dosimetry advantage of the Bragg peak. The Bragg peak is a phenomenon exploited by proton beam therapy to concentrate the effect of the beams on the tumor while minimizing damage to critical structures and other health tissues within the patient.

A New Phantom And Gradient Isocenter Estimation For Magnetic Resonance Imaging Distortion Correction, Zongqi Cai

Theses Digitization Project

The purpose of this study was to develop and implement a numerical software based method that can accurately correct the distortion of MR images generated by 3T MRI scanner. To accomplish this, a new phantom has been designed from scratch to capture the distortions inside 3T MRI scanner. An algorithm has been developed, based on the unique geometric feature of the new phantom, to estimate the location of gradient isocenter of the magnetic field inside 3T MRI scanner for the first time.

Alternative Hull Detection Techniques For Preprocessing In Proton Computed Tomography Reconstruction, Blake Edward Schultze

Theses Digitization Project

The purpose of this study was to develop computationally efficient hull detection techniques appropriate for image reconstruction using sparse matrices. The hull detection techniques investigated were space carving (SC), modified space carving (MSC), and space modeling (SM) and these were compared to the cone-beam version of filtered back projection (FBP) algorithm in terms of their computation time and the quality of the object hull they produced.

Towards An Early Software Estimation Using Log-Linear Regression And A Multilayer Perceptron Model, Ali Bou Nassif, Nfa-Estimation, Luiz Fernando Capretz

Electrical and Computer Engineering Publications

Software estimation is a tedious and daunting task in project management and software development. Software estimators are notorious in predicting software effort and they have been struggling in the past decades to provide new models to enhance software estimation. The most critical and crucial part of software estimation is when estimation is required in the early stages of the software life cycle where the problem to be solved has not yet been completely revealed. This paper presents a novel log-linear regression model based on the use case point model (UCP) to calculate the software effort based on use case diagrams. …

Eef-Cas: An Effort Estimation Framework With Customizable Attribute Selection, Katarina Grolinger, Besa Muslimi, Miriam A.M. Capretz, Mark Benko

Electrical and Computer Engineering Publications

Existing estimation frameworks generally provide one-size-fits-all solutions that fail to produce accurate estimates in most environments. Research has shown that the accomplishment of accurate effort estimates is a long-term process that, above all, requires the extensive collection of effort estimation data by each organization. Collected data is generally characterized by a set of attributes that are believed to affect the development effort. The attributes that most affect development effort vary widely depending on the type of product being developed and the environment in which it is being developed. Thus, any new estimation framework must offer the flexibility of customizable attribute …

Knowledge As A Service Framework For Disaster Data Management, Katarina Grolinger, Emna Mezghani, Miriam Am Capretz, Ernesto Exposito

Electrical and Computer Engineering Publications

Each year, a number of natural disasters strike across the globe, killing hundreds and causing billions of dollars in property and infrastructure damage. Minimizing the impact of disasters is imperative in today’s society. As the capabilities of software and hardware evolve, so does the role of information and communication technology in disaster mitigation, preparation, response, and recovery. A large quantity of disaster-related data is available, including response plans, records of previous incidents, simulation data, social media data, and Web sites. However, current data management solutions offer few or no integration capabilities. Moreover, recent advances in cloud computing, big data, and …

Extension Of Object-Oriented Metrics Suite For, John Michura, Miriam A M Capretz, Shuying Wang

Electrical and Computer Engineering Publications

Software developers require information to understand the characteristics of systems, such as complexity and maintainability. In order to further understand and determine characteristics of object-oriented (OO) systems, this paper describes research that identifies attributes that are valuable in determining the difficulty in implementing changes during maintenance, as well as the possible effects that such changes may produce. A set of metrics are proposed to quantify and measure these attributes. The proposed complexity metrics are used to determine the difficulty in implementing changes through the measurement of method complexity, method diversity, and complexity density. The paper establishes impact metrics to determine …