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Research Collection School Of Computing and Information Systems

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Verification Of Functional And Non-Functional Requirements Of Web Service Composition, Manman Chen, Tian Huat Tan, Jun Sun, Yang Liu, Jun Pang, Xiaohong Li Jan 2013

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 Jan 2013

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 Jan 2013

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 Jan 2013

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) …


Robust Non-Parametric Data Fitting For Correspondence Modeling, Wen-Yan Lin, Ming-Ming Cheng, Shuai Zheng, Jiangbo Lu, Nigel Crook Jan 2013

Robust Non-Parametric Data Fitting For Correspondence Modeling, Wen-Yan Lin, Ming-Ming Cheng, Shuai Zheng, Jiangbo Lu, Nigel Crook

Research Collection School Of Computing and Information Systems

We propose a generic method for obtaining nonparametric image warps from noisy point correspondences. Our formulation integrates a huber function into a motion coherence framework. This makes our fitting function especially robust to piecewise correspondence noise (where an image section is consistently mismatched). By utilizing over parameterized curves, we can generate realistic nonparametric image warps from very noisy correspondence. We also demonstrate how our algorithm can be used to help stitch images taken from a panning camera by warping the images onto a virtual push-broom camera imaging plane.


Efficient Salient Region Detection With Soft Image Abstraction, Ming-Ming Cheng, Jonathan Warrell, Wen-Yan Lin, Shuai Zheng, Vibhav Vineet, Nigel Crook Jan 2013

Efficient Salient Region Detection With Soft Image Abstraction, Ming-Ming Cheng, Jonathan Warrell, Wen-Yan Lin, Shuai Zheng, Vibhav Vineet, Nigel Crook

Research Collection School Of Computing and Information Systems

Detecting visually salient regions in images is one of the fundamental problems in computer vision. We propose a novel method to decompose an image into large scale perceptually homogeneous elements for efficient salient region detection, using a soft image abstraction representation. By considering both appearance similarity and spatial distribution of image pixels, the proposed representation abstracts out unnecessary image details, allowing the assignment of comparable saliency values across similar regions, and producing perceptually accurate salient region detection. We evaluate our salient region detection approach on the largest publicly available dataset with pixel accurate annotations. The experimental results show that the …


Verifying Linearizability Via Optimized Refinement Checking, Yang Liu, Wei Chen, Yanhong A. Liu, Jun Sun, Shao Jie Zhang, Jin Song Dong Dong Jan 2013

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 Jan 2013

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 …


Engagingness And Responsiveness Behavior Models On The Enron Email Network And Its Application To Email Reply Order Prediction, Byung-Won On, Ee Peng Lim, Jing Jiang, Loo Nin Teow Jan 2013

Engagingness And Responsiveness Behavior Models On The Enron Email Network And Its Application To Email Reply Order Prediction, Byung-Won On, Ee Peng Lim, Jing Jiang, Loo Nin Teow

Research Collection School Of Computing and Information Systems

In email networks, user behaviors affect the way emails are sent and replied. While knowing these user behaviors can help to create more intelligent email services, there has not been much research into mining these behaviors. In this paper, we investigate user engagingness and responsiveness as two interaction behaviors that give us useful insights into how users email one another. Engaging users are those who can effectively solicit responses from other users. Responsive users are those who are willing to respond to other users. By modeling such behaviors, we are able to mine them and to identify engaging or responsive …


Sensor Feature Selection And Combination For Stress Identification Using Combinatorial Fusion, Yong Deng, Zhonghai Wu, Chao-Hsien Chu, Qixun Zhang, D. Frank Hsu Jan 2013

Sensor Feature Selection And Combination For Stress Identification Using Combinatorial Fusion, Yong Deng, Zhonghai Wu, Chao-Hsien Chu, Qixun Zhang, D. Frank Hsu

Research Collection School Of Computing and Information Systems

The identification of stressfulness under certain driving condition is an important issue for safety, security and health. Sensors and systems have been placed or implemented as wearable devices for drivers. Features are extracted from the data collected and combined to predict symptoms. The challenge is to select the feature set most relevant for stress. In this paper, we propose a feature selection method based on the performance and the diversity between two features. The feature sets selected are then combined using a combinatorial fusion. We also compare our results with other combination methods such as naïve Bayes, support vector machine, …


Mining Indirect Antagonistic Communities From Social Interactions, Kuan Zhang, David Lo, Ee Peng Lim, Philips Kokoh Prasetyo Jan 2013

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 …


Moving Object Detection With Laser Scanners, Christoph Mertz, Luis E. Navarro-Serment, Robert Maclachlan, Paul Rybski, Aaron Steinfeld, Arne Suppe, Christopher Urmson, Nicolas Vandapel, Martial Hebert, Chuck Thorpe, David Duggins, Jay Gowdy Jan 2013

Moving Object Detection With Laser Scanners, Christoph Mertz, Luis E. Navarro-Serment, Robert Maclachlan, Paul Rybski, Aaron Steinfeld, Arne Suppe, Christopher Urmson, Nicolas Vandapel, Martial Hebert, Chuck Thorpe, David Duggins, Jay Gowdy

Research Collection School Of Computing and Information Systems

The detection and tracking of moving objects is an essential task in robotics. The CMU-RI Navlab group has developed such a system that uses a laser scanner as its primary sensor. We will describe our algorithm and its use in several applications. Our system worked successfully on indoor and outdoor platforms and with several different kinds and configurations of two-dimensional and three-dimensional laser scanners. The applications vary from collision warning systems, people classification, observing human tracks, and input to a dynamic planner. Several of these systems were evaluated in live field tests and shown to be robust and reliable. (C) …


Improving Internet Security Through Information Disclosure: A Field Quasi-Experiment, Qian Tang, Leigh L. Linden, John S. Quarterman, Andrew B. Whinston Jan 2013

Improving Internet Security Through Information Disclosure: A Field Quasi-Experiment, Qian Tang, Leigh L. Linden, John S. Quarterman, Andrew B. Whinston

Research Collection School Of Computing and Information Systems

Cybersecurity is a national priority in this big data era. Because of negative externalities and the resulting lack of economic incentives, companies often underinvest in security controls, despite government and industry recommendations. Although many existing studies on security have explored technical solutions, only a few have looked at the economic motivations. To fill the gap, we propose an approach to increase the incentives of organizations to address security problems. Specifically, we utilize and process existing security vulnerability data, derive explicit security performance information, and disclose the information as feedback to organizations and the public. We regularly release information on the …


Seller Diversity On A Technology-Based Platform, Ruhai Wu, Mei Lin Jan 2013

Seller Diversity On A Technology-Based Platform, Ruhai Wu, Mei Lin

Research Collection School Of Computing and Information Systems

Managing a technology portfolio is one of the great challenges for sustained success, especially in high-technology industrieswhere technologies can be a major selling point. For engineers, this portfolio is more of a toolbox for solving design problems,but in large organizations there can be so many technologies used in different business areas that even the engineers may not beaware of all of them. When the same technologies are used in different types of products, knowledge about them can also begenerated by various groups within an organization. To improve the usefulness of a company's technology base, this paperproposes the use of a …


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 Jan 2013

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.


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 Jan 2013

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 …


Utility Of Potential Misdiagnoses In Predicting Foodborne Outbreaks, Lucia Lucia, Artur Dubrawski, Lujie Chen Jan 2013

Utility Of Potential Misdiagnoses In Predicting Foodborne Outbreaks, Lucia Lucia, Artur Dubrawski, Lujie Chen

Research Collection School Of Computing and Information Systems

To investigate utility of using inpatient and emergency room diagnoses to detect outbreaks of Salmonellosis in humans. To quantify the impact of including in the analysis cases diagnosed with conditions that may have physiological appearance similar to Salmonellosis.


Valuation Of Participation In Social Gaming, Kwansoo Kim, Byungjoon Yoo, Robert J. Kauffman Jan 2013

Valuation Of Participation In Social Gaming, Kwansoo Kim, Byungjoon Yoo, Robert J. Kauffman

Research Collection School Of Computing and Information Systems

This study examines the value of the time that a user spends to participate in a social game. We focus on how a massive multiplayer online role-playing game (MMORPG) vendor can establish prices to encourage participation and retain its players. We estimate value through an application of the hedonic pricing model and analyze a data set for an MMORPG in Korea. The results permit us to estimate the value of game-playing time in monetary terms. Based on our empirical results, we propose an economic model and conduct numerical simulation to show how a game vendor can apply differential pricing in …


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 Jan 2013

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 …


Guardian: Hypervisor As Security Foothold For Personal Computers, Yueqiang Cheng, Xuhua Ding Jan 2013

Guardian: Hypervisor As Security Foothold For Personal Computers, Yueqiang Cheng, Xuhua Ding

Research Collection School Of Computing and Information Systems

Personal computers lack of a security foothold to allow the end-users to protect their systems or to mitigate the damage. Existing candidates either rely on a large Trusted Computing Base (TCB) or are too costly to widely deploy for commodity use. To fill this gap, we propose a hypervisor-based security foothold, named as Guardian, for commodity personal computers. We innovate a bootup and shutdown mechanism to achieve both integrity and availability of Guardian. We also propose two security utilities based on Guardian. One is a device monitor which detects malicious manipulation on camera and network adaptors. The other is hyper-firewall …


Accountable Trapdoor Sanitizable Signatures, Junzuo Lai, Xuhua Ding, Yongdong Wu Jan 2013

Accountable Trapdoor Sanitizable Signatures, Junzuo Lai, Xuhua Ding, Yongdong Wu

Research Collection School Of Computing and Information Systems

Sanitizable signature (SS) allows a signer to partly delegate signing rights to a predetermined party, called sanitizer, who can later modify certain designated parts of a message originally signed by the signer and generate a new signature on the sanitized message without interacting with the signer. One of the important security requirements of sanitizable signatures is accountability, which allows the signer to prove, in case of dispute, to a third party that a message was modified by the sanitizer. Trapdoor sanitizable signature (TSS) enables a signer of a message to delegate the power of sanitization to any parties at anytime …


Verifiable And Private Top-K Monitoring, Xuhua Ding, Hwee Hwa Pang Jan 2013

Verifiable And Private Top-K Monitoring, Xuhua Ding, Hwee Hwa Pang

Research Collection School Of Computing and Information Systems

In a data streaming model, records or documents are pushed from a data owner, via untrusted third-party servers, to a large number of users with matching interests. The match in interest is calculated from the correlation between each pair of document and user query. For scalability and availability reasons, this calculation is delegated to the servers, which gives rise to the need to protect the privacy of the documents and user queries. In addition, the users need to guard against the eventuality of a server distorting the correlation score of the documents to manipulate which documents are highlighted to certain …


Symbolic Model-Checking Of Stateful Timed Csp Using Bdd And Digitization, Truong Khanh Nguyen, Jun Sun, Yang Liu, Jin Song Dong Dec 2012

Symbolic Model-Checking Of Stateful Timed Csp Using Bdd And Digitization, Truong Khanh Nguyen, Jun Sun, Yang Liu, Jin Song Dong

Research Collection School Of Computing and Information Systems

Stateful Timed CSP has been recently proposed to model (and verify) hierarchical real-time systems. It is an expressive modeling language which combines data structure/operations, complicated control flows (modeled using compositional process operators adopted from Timed CSP), and real-time requirements like deadline and within. It has been shown that Stateful Timed CSP is equivalent to closed timed automata with silent transitions, which implies that the timing constraints of Stateful Timed CSP can be captured using explicit tick events, through digitization. In order to tackle the state space explosion problem, we develop a BDD-based symbolic model checking approach to verify Stateful Timed …


Visualization For Anomaly Detection And Data Management By Leveraging Network, Sensor And Gis Techniques, Zhaoxia Wang, Chee Seng Chong, Rick S. M. Goh, Wanqing Zhou, Dan Peng, Hoong Chor Chin Dec 2012

Visualization For Anomaly Detection And Data Management By Leveraging Network, Sensor And Gis Techniques, Zhaoxia Wang, Chee Seng Chong, Rick S. M. Goh, Wanqing Zhou, Dan Peng, Hoong Chor Chin

Research Collection School Of Computing and Information Systems

This paper studies the importance of visualization for discerning and interpreting patterns of data and its application for solving real problems, such as anomaly detection and data management. There are various ways to realize visualization to cater to the needs of numerous real life applications. Depending on needs, a combination of some of these ways may be required for presenting an effective visualization. The authors present visualization schemes for anomaly detection/condition monitoring and data management by leveraging network techniques and combining them with modern techniques such as sensor, database, mobile communication, GPS and GIS techniques. Two case studies are presented …


Ibinhunt: Binary Hunting With Inter-Procedural Control Flow, Jiang Ming, Meng Pan, Debin Gao Dec 2012

Ibinhunt: Binary Hunting With Inter-Procedural Control Flow, Jiang Ming, Meng Pan, Debin Gao

Research Collection School Of Computing and Information Systems

Techniques have been proposed to find the semantic differences between two binary programs when the source code is not available. Analyzing control flow, and in particular, intra-procedural control flow, has become an attractive technique in the latest binary diffing tools since it is more resistant to syntactic, but non-semantic, differences. However, this makes such techniques vulnerable to simple function obfuscation techniques (e.g., function inlining) attackers any malware writers could use. In this paper, we first show function obfuscation as an attack to such binary diffing techniques, and then propose iBinHunt which uses deep taint and automatic input generation to find …


Lagrangian Relaxation For Large-Scale Multi-Agent Planning, Geoffrey J. Gordon, Pradeep Varakantham, William Yeoh, Hoong Chuin Lau, Ajay S. Aravamudhan, Shih-Fen Cheng Dec 2012

Lagrangian Relaxation For Large-Scale Multi-Agent Planning, Geoffrey J. Gordon, Pradeep Varakantham, William Yeoh, Hoong Chuin Lau, Ajay S. Aravamudhan, Shih-Fen Cheng

Research Collection School Of Computing and Information Systems

Multi-agent planning is a well-studied problem with various applications including disaster rescue, urban transportation and logistics, both for autonomous agents and for decision support to humans. Due to computational constraints, existing research typically focuses on one of two scenarios: unstructured domains with many agents where we are content with heuristic solutions, or domains with small numbers of agents or special structure where we can provide provably near-optimal solutions. By contrast, in this paper, we focus on providing provably near-optimal solutions for domains with large numbers of agents, by exploiting a common domain-general property: if individual agents each have limited influence …


Eliciting Usable Gestures For Multi-Display Environments, Teddy Seyed, Chris Burns, Mario Costa Sousa, Frank Maurer, Anthony Tang Dec 2012

Eliciting Usable Gestures For Multi-Display Environments, Teddy Seyed, Chris Burns, Mario Costa Sousa, Frank Maurer, Anthony Tang

Research Collection School Of Computing and Information Systems

Multi-display environments (MDEs) have advanced rapidly in recent years, incorporating multi-touch tabletops, tablets, wall displays and even position tracking systems. Designers have proposed a variety of interesting gestures for use in an MDE, some of which involve a user moving their hands, arms, body or even a device itself. These gestures are often used as part of interactions to move data between the various components of an MDE, which is a longstanding research problem. But designers, not users, have created most of these gestures and concerns over implementation issues such as recognition may have influenced their design. We performed a …


Agent-Based Virtual Humans In Co-Space: An Evaluative Study, Yilin Kang, Ah-Hwee Tan, Fiona Fui-Hoon Nah Dec 2012

Agent-Based Virtual Humans In Co-Space: An Evaluative Study, Yilin Kang, Ah-Hwee Tan, Fiona Fui-Hoon Nah

Research Collection School Of Computing and Information Systems

Co-Space refers to interactive virtual environment modelled after the real world in terms of look-and-feel, functionalities and services. We have developed a 3D virtual world named Nanyang Technological University (NTU) CoSpace populated with virtual human characters. Three key requirements of realistic virtual humans in the virtual world have been identified, namely (1) autonomy: agents can function on their own; (2) interactivity: agents can interact naturally with players; and (3) personality: agents can exhibit human traits and characteristics. Working towards these challenges, we propose a brain-inspired agent architecture that integrates goal-directed autonomy, natural language interaction and human-like personality. We conducted an …


Critical Success Factors Of Location-Based Services, Natalie J. P. Chin, Keng Siau Dec 2012

Critical Success Factors Of Location-Based Services, Natalie J. P. Chin, Keng Siau

Research Collection School Of Computing and Information Systems

Location-based services evolved with the advancement in mobile technology and wireless technology. Researchers have studied location-based services in terms of privacy, trust, and user acceptance. Statistics suggest the percentage of location-based services users is still relatively low. Therefore, the main objective of this study was to gain a comprehensive and holistic understanding of the critical success factors of location-based services. The electronic brainstorming approach was used to gather the opinions of an expert group of practitioners, researchers, and users on the critical success factors of location-based services. Through grouping similar factors together based on past literature, 15 categories of critical …


Cost-Sensitive Online Classification, Jialei Wang, Peilin Zhao, Steven C. H. Hoi Dec 2012

Cost-Sensitive Online Classification, Jialei Wang, Peilin Zhao, Steven C. H. Hoi

Research Collection School Of Computing and Information Systems

Both cost-sensitive classification and online learning have been extensively studied in data mining and machine learning communities, respectively. However, very limited study addresses an important intersecting problem, that is, “Cost-Sensitive Online Classification". In this paper, we formally study this problem, and propose a new framework for Cost-Sensitive Online Classification by directly optimizing cost-sensitive measures using online gradient descent techniques. Specifically, we propose two novel cost-sensitive online classification algorithms, which are designed to directly optimize two well-known cost-sensitive measures: (i) maximization of weighted sum of sensitivity and specificity, and (ii) minimization of weighted misclassification cost. We analyze the theoretical bounds of …