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Articles 61 - 86 of 86
Full-Text Articles in Physical Sciences and Mathematics
Arraytrack: A Fine-Grained Indoor Location System, Jie Xiong, Kyle Jamieson
Arraytrack: A Fine-Grained Indoor Location System, Jie Xiong, Kyle Jamieson
Research Collection School Of Computing and Information Systems
With myriad augmented reality, social networking, and retail shopping applications all on the horizon for the mobile handheld, a fast and accurate location technology will become key to a rich user experience. When roaming outdoors, users can usually count on a clear GPS signal for accurate location, but indoors, GPS often fades, and so up until recently, mobiles have had to rely mainly on rather coarse-grained signal strength readings. What has changed this status quo is the recent trend of dramatically increasing numbers of antennas at the indoor access point, mainly to bolster capacity and coverage with multiple-input, multiple-output (MIMO) …
Predicting Sql Injection And Cross Site Scripting Vulnerabilities Through Mining Input Sanitization Patterns, Lwin Khin Shar, Hee Beng Kuan Tan
Predicting Sql Injection And Cross Site Scripting Vulnerabilities Through Mining Input Sanitization Patterns, Lwin Khin Shar, Hee Beng Kuan Tan
Research Collection School Of Computing and Information Systems
ContextSQL injection (SQLI) and cross site scripting (XSS) are the two most common and serious web application vulnerabilities for the past decade. To mitigate these two security threats, many vulnerability detection approaches based on static and dynamic taint analysis techniques have been proposed. Alternatively, there are also vulnerability prediction approaches based on machine learning techniques, which showed that static code attributes such as code complexity measures are cheap and useful predictors. However, current prediction approaches target general vulnerabilities. And most of these approaches locate vulnerable code only at software component or file levels. Some approaches also involve process attributes that …
Towards Omnidirectional Passive Human Detection, Zimu Zhou, Zheng Yang, Chenshu Wu, Longfei Shangguan, Yunhao Liu
Towards Omnidirectional Passive Human Detection, Zimu Zhou, Zheng Yang, Chenshu Wu, Longfei Shangguan, Yunhao Liu
Research Collection School Of Computing and Information Systems
Passive human detection and localization serve as key enablers for various pervasive applications such as smart space, human-computer interaction and asset security. The primary concern in devising scenario-tailored detecting systems is the coverage of their monitoring units. In conventional radio-based schemes, the basic unit tends to demonstrate a directional coverage, even if the underlying devices are all equipped with omnidirectional antennas. Such an inconsistency stems from the link-centric architecture, creating an anisotropic wireless propagating environment. To achieve an omnidirectional coverage while retaining the link-centric architecture, we propose the concept of Omnidirectional Passive Human Detection, and investigate to harness the PHY …
Predicting Project Outcome Leveraging Socio-Technical Network Patterns, Didi Surian, Yuan Tian, David Lo, Hong Cheng, Ee Peng Lim
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 …
Understanding Widespread Changes: A Taxonomic Study, Shaowei Wang, David Lo, Lingxiao Jiang
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 …
Network Structure Of Social Coding In Github, Ferdian Thung, Tegawende F. Bissyande, David Lo, Lingxiao Jiang
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 …
Understanding Widespread Changes: A Taxonomic Study, Shaowei Wang, David Lo, Lingxiao Jiang
Understanding Widespread Changes: A Taxonomic Study, Shaowei Wang, David Lo, Lingxiao Jiang
Research Collection School Of Computing and Information Systems
No abstract provided.
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
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
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 …
Infrastructure-Assisted Smartphone-Based Adl Recognition In Multi-Inhabitant Smart Environments, Nirmalya Roy, Archan Misra, Diane Cook
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 …
Empirical Evaluation Of Bug Linking, Tegawende F. Bissyande, Ferdian Thung, Shaowei Wang, David Lo, Lingxiao Jiang, Laurent Reveillere
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, …
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
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 …
Combining Crowdsourcing And Google Street View To Identify Street-Level Accessibility Problems, Kotaro Hara, Victoria Le, Jon Froehlich
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 …
Verification Of Functional And Non-Functional Requirements Of Web Service Composition, Manman Chen, Tian Huat Tan, Jun Sun, Yang Liu, Jun Pang, Xiaohong Li
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
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 …
A Utp Semantics For Communicating Processes With Shared Variables, Ling Shi, Yongxin Zhao, Yang Liu, Jun Sun, Jin Song Dong, Shengchao Qin
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 …
Vtrust: A Formal Modeling And Verification Framework For Virtualization Systems, Jianan Hao, Yang Liu, Wentong Cai, Guangdong Bai, Jun Sun
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
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
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
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.
Mining Indirect Antagonistic Communities From Social Interactions, Kuan Zhang, David Lo, Ee Peng Lim, Philips Kokoh Prasetyo
Mining Indirect Antagonistic Communities From Social Interactions, Kuan Zhang, David Lo, Ee Peng Lim, Philips Kokoh Prasetyo
Research Collection School Of Computing and Information Systems
Antagonistic communities refer to groups of people with opposite tastes, opinions, and factions within a community. Given a set of interactions among people in a community, we develop a novel pattern mining approach to mine a set of antagonistic communities. In particular, based on a set of user-specified thresholds, we extract a set of pairs of communities that behave in opposite ways with one another. We focus on extracting a compact lossless representation based on the concept of closed patterns to prevent exploding the number of mined antagonistic communities. We also present a variation of the algorithm using a divide …
Clustering Of Search Trajectory And Its Application To Parameter Tuning, Linda Lindawati, Hoong Chuin Lau, David Lo
Clustering Of Search Trajectory And Its Application To Parameter Tuning, Linda Lindawati, Hoong Chuin Lau, David Lo
Research Collection School Of Computing and Information Systems
This paper is concerned with automated classification of Combinatorial Optimization Problem instances for instance-specific parameter tuning purpose. We propose the CluPaTra Framework, a generic approach to CLUster instances based on similar PAtterns according to search TRAjectories and apply it on parameter tuning. The key idea is to use the search trajectory as a generic feature for clustering problem instances. The advantage of using search trajectory is that it can be obtained from any local-search based algorithm with small additional computation time. We explore and compare two different search trajectory representations, two sequence alignment techniques (to calculate similarities) as well as …
Improving Public Transit Accessibility For Blind Riders By Crowdsourcing Bus Stop Landmark Locations With Google Street View, Kotaro Hara, Shiri Azenkot, Megan Campbell, Cynthia L. Bennett, Vicki Le, Sean Pannella, Robert Moore, Kelly Minckler, Rochelle H. Ng, Jon E. Froehlich
Improving Public Transit Accessibility For Blind Riders By Crowdsourcing Bus Stop Landmark Locations With Google Street View, Kotaro Hara, Shiri Azenkot, Megan Campbell, Cynthia L. Bennett, Vicki Le, Sean Pannella, Robert Moore, Kelly Minckler, Rochelle H. Ng, Jon E. Froehlich
Research Collection School Of Computing and Information Systems
Low-vision and blind bus riders often rely on known physicallandmarks to help locate and verify bus stop locations (e.g., bysearching for a shelter, bench, newspaper bin). However, there arecurrently few, if any, methods to determine this information apriori via computational tools or services. In this paper, weintroduce and evaluate a new scalable method for collecting busstop location and landmark descriptions by combining onlinecrowdsourcing and Google Street View (GSV). We conduct andreport on three studies in particular: (i) a formative interviewstudy of 18 people with visual impairments to inform the designof our crowdsourcing tool; (ii) a comparative study examiningdifferences between physical …
An Initial Study Of Automatic Curb Ramp Detection With Crowdsourced Verification Using Google Street View Images, Kotaro Hara, Jin Sun, Jonah Chazan, David Jacobs, Jin Froehlich
An Initial Study Of Automatic Curb Ramp Detection With Crowdsourced Verification Using Google Street View Images, Kotaro Hara, Jin Sun, Jonah Chazan, David Jacobs, Jin Froehlich
Research Collection School Of Computing and Information Systems
In our previous research, we examined whether minimallytrained crowd workers could find, categorize, and assesssidewalk accessibility problems using Google Street View(GSV) images. This poster paper presents a first step towardscombining automated methods (e.g., machine visionbasedcurb ramp detectors) in concert with human computationto improve the overall scalability of our approach.
Understanding And Rejecting Errant Touches On Multi-Touch Tablets, Ke Shu
Understanding And Rejecting Errant Touches On Multi-Touch Tablets, Ke Shu
Dissertations and Theses Collection (Open Access)
Given the pervasion of multi-touch tablet, pen-based applications have rapidly moved onto this new platform. Users draw both with bare fingers and using capacitive pens as they would do on paper in the past. Unlike paper, these tablets cannot distinguish legitimate finger/pen input from accidental touches by other parts of the user’s hand. In this thesis, we refer it to as errant touch rejection problem since users may unintentionally touch the screen with other parts of their hand. In this thesis, I design, implement and evaluate new approaches, bezel-focus rejection, of preventing errant touches on multi-touch tablets. I began the …
State Space Reduction For Sensor Networks Using Two-Level Partial Order Reduction, Manchun Zheng, David Sanán, Jun Sun, Yang Liu, Jin Song Dong, Yu Gu
State Space Reduction For Sensor Networks Using Two-Level Partial Order Reduction, Manchun Zheng, David Sanán, Jun Sun, Yang Liu, Jin Song Dong, Yu Gu
Research Collection School Of Computing and Information Systems
Wireless sensor networks may be used to conduct critical tasks like fire detection or surveillance monitoring. It is thus important to guarantee the correctness of such systems by systematically analyzing their behaviors. Formal verification of wireless sensor networks is an extremely challenging task as the state space of sensor networks is huge, e.g., due to interleaving of sensors and intra-sensor interrupts. In this work, we develop a method to reduce the state space significantly so that state space exploration methods can be applied to a much smaller state space without missing a counterexample. Our method explores the nature of networked …