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Research Collection School Of Computing and Information Systems

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Conditional Proxy Broadcast Re-Encryption, Cheng-Kang Chu, Jian Weng, Sherman S. W. Chow, Jianying Zhou, Robert H. Deng Jul 2009

Conditional Proxy Broadcast Re-Encryption, Cheng-Kang Chu, Jian Weng, Sherman S. W. Chow, Jianying Zhou, Robert H. Deng

Research Collection School Of Computing and Information Systems

A proxy re-encryption (PRE) scheme supports the delegation of decryption rights via a proxy, who makes the ciphertexts decryptable by the delegatee. PRE is useful in various applications such as encrypted email forwarding. In this paper, we introduce a more generalized notion of conditional proxy broadcast re-encryption (CPBRE). A CPBRE scheme allows Alice to generate a re-encryption key for some condition specified during the encryption, such that the re-encryption power of the proxy is restricted to that condition only. This enables a more fine-grained delegation of decryption right. Moreover, Alice can delegate decryption rights to a set of users at …

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Automatic Steering Of Behavioral Model Inference, David Lo, Leonardo Mariani, Mauro Pezze Jul 2009

Automatic Steering Of Behavioral Model Inference, David Lo, Leonardo Mariani, Mauro Pezze

Research Collection School Of Computing and Information Systems

Many testing and analysis techniques use finite state models to validate and verify the quality of software systems. Since the specification of such models is complex and time-consuming, researchers defined several techniques to extract finite state models from code and traces. Automatically generating models requires much less effort than designing them, and thus eases the verification and validation of large software systems. However, when models are inferred automatically, the precision of the mining process is critical. Behavioral models mined with imprecise processes can include many spurious behaviors, and can thus compromise the results of testing and analysis techniques that use …

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Spatial Cloaking Revisited: Distinguishing Information Leakage From Anonymity, Kar Way Tan, Yimin Lin, Kyriakos Mouratidis Jul 2009

Spatial Cloaking Revisited: Distinguishing Information Leakage From Anonymity, Kar Way Tan, Yimin Lin, Kyriakos Mouratidis

Research Collection School Of Computing and Information Systems

Location-based services (LBS) are receiving increasing popularity as they provide convenience to mobile users with on-demand information. The use of these services, however, poses privacy issues as the user locations and queries are exposed to untrusted LBSs. Spatial cloaking techniques provide privacy in the form of k-anonymity; i.e., they guarantee that the (location of the) querying user u is indistinguishable from at least k-1 others, where k is a parameter specified by u at query time. To achieve this, they form a group of k users, including u, and forward their minimum bounding rectangle (termed anonymzing spatial region, ASR) to …

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Learning And Inferencing In User Ontology For Personalized Semantic Web Search, Xing Jiang, Ah-Hwee Tan Jul 2009

Learning And Inferencing In User Ontology For Personalized Semantic Web Search, Xing Jiang, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

User modeling is aimed at capturing the users’ interests in a working domain, which forms the basis of providing personalized information services. In this paper, we present an ontology based user model, called user ontology, for providing personalized information service in the Semantic Web. Different from the existing approaches that only use concepts and taxonomic relations for user modeling, the proposed user ontology model utilizes concepts, taxonomic relations, and non-taxonomic relations in a given domain ontology to capture the users’ interests. As a customized view of the domain ontology, a user ontology provides a richer and more precise representation of …

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Integrating Specification And Programs For System Modeling And Verification, Jun Sun, Yang Liu, Jin Song Dong, Chunqing Chen Jul 2009

Integrating Specification And Programs For System Modeling And Verification, Jun Sun, Yang Liu, Jin Song Dong, Chunqing Chen

Research Collection School Of Computing and Information Systems

High level specification languages like CSP use mathematical objects as abstractions to represent systems and processes. System behaviors are described as process expressions combined with compositional operators, which are associated with elegant algebraic laws for system analysis. Nonetheless, modeling systems with non-trivial data and functional aspects using CSP remains difficult. In this work, we propose a modeling language named CSP# (short for communicating sequential programs) which integrates high-level modeling operators with low-level procedural codes, for the purpose of efficient mechanical system verification. We demonstrate that data operations can be modeled as terminating sequential programs, which can be composed using high-level …

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Creating Human-Like Autonomous Players In Real-Time First Person Shooter Computer Games, Di Wang, Budhitama Subagdja, Ah-Hwee Tan, Gee-Wah Ng Jul 2009

Creating Human-Like Autonomous Players In Real-Time First Person Shooter Computer Games, Di Wang, Budhitama Subagdja, Ah-Hwee Tan, Gee-Wah Ng

Research Collection School Of Computing and Information Systems

This paper illustrates how we create a software agent by employing FALCON, a self-organizing neural network that performs reinforcement learning, to play a well-known first person shooter computer game known as Unreal Tournament 2004. Through interacting with the game environment and its opponents, our agent learns in real-time without any human intervention. Our agent bot participated in the 2K Bot Prize competition, similar to the Turing test for intelligent agents, wherein human judges were tasked to identify whether their opponents in the game were human players or virtual agents. To perform well in the competition, an agent must act like …

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A Bayesian Approach Integrating Regional And Global Features For Image Semantic Learning, Luong-Dong Nguyen, Ghim-Eng Yap, Ying Liu, Ah-Hwee Tan, Liang-Tien Chia, Joo-Hwee Lim Jul 2009

A Bayesian Approach Integrating Regional And Global Features For Image Semantic Learning, Luong-Dong Nguyen, Ghim-Eng Yap, Ying Liu, Ah-Hwee Tan, Liang-Tien Chia, Joo-Hwee Lim

Research Collection School Of Computing and Information Systems

In content-based image retrieval, the “semantic gap” between visual image features and user semantics makes it hard to predict abstract image categories from low-level features. We present a hybrid system that integrates global features (Gfeatures) and region features (R-features) for predicting image semantics. As an intermediary between image features and categories, we introduce the notion of mid-level concepts, which enables us to predict an image’s category in three steps. First, a G-prediction system uses G-features to predict the probability of each category for an image. Simultaneously, a R-prediction system analyzes R-features to identify the probabilities of mid-level concepts in that …

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Exploring Inter-Concept Relationship With Context Space For Semantic Video Indexing, Xiao-Yong Wei, Yu-Gang Jiang, Chong-Wah Ngo Jul 2009

Exploring Inter-Concept Relationship With Context Space For Semantic Video Indexing, Xiao-Yong Wei, Yu-Gang Jiang, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

Semantic concept detectors are often individually and independently developed. Using peripherally related concepts for leveraging the power of joint detection, which is referred to as context-based concept fusion (CBCF), has been one of the focus studies in recent years. This paper proposes the construction of a context space and the exploration of the space for CBCF. Context space considers the global consistency of concept relationship, addresses the problem of missing annotation, and is extensible for cross-domain contextual fusion. The space is linear and can be built by modeling the inter-concept relationship through annotation provided by either manual labeling or machine …

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Towards Expressive Specification And Efficient Model Checking, Jin Song Dong, Jun Sun Jul 2009

Towards Expressive Specification And Efficient Model Checking, Jin Song Dong, Jun Sun

Research Collection School Of Computing and Information Systems

System modeling is important and highly non-trivial. The choice of specification language is an important factor in the success of the entire development. The language should cover several facets of the requirements and the model should precisely capture (up to abstraction of irrelevant details) an existing system or a system to be built. The language should have a semantic model suitable to study the behaviors of the system and to establish the validity of desired properties. A formal model can be the basis for a variety of system development activities, e.g., system simulation, visualization, verification or prototype synthesis.

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Continuous Obstructed Nearest Neighbor Queries In Spatial Databases, Yunjun Gao, Baihua Zheng Jul 2009

Continuous Obstructed Nearest Neighbor Queries In Spatial Databases, Yunjun Gao, Baihua Zheng

Research Collection School Of Computing and Information Systems

In this paper, we study a novel form of continuous nearest neighbor queries in the presence of obstacles, namely continuous obstructed nearest neighbor (CONN) search. It considers the impact of obstacles on the distance between objects, which is ignored by most of spatial queries. Given a data set P, an obstacle set O, and a query line segment q in a two-dimensional space, a CONN query retrieves the nearest neighbor of each point on q according to the obstructed distance, i.e., the shortest path between them without crossing any obstacle. We formulate CONN search, analyze its unique properties, and develop …

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Fair Model Checking With Process Counter Abstraction, Jun Sun, Yang Liu, Abhik Roychoudhury, Shanshan Liu, Jin Song Dong Jun 2009

Fair Model Checking With Process Counter Abstraction, Jun Sun, Yang Liu, Abhik Roychoudhury, Shanshan Liu, Jin Song Dong

Research Collection School Of Computing and Information Systems

Parameterized systems are characterized by the presence of a large (or even unbounded) number of behaviorally similar processes, and they often appear in distributed/concurrent systems. A common state space abstraction for checking parameterized systems involves not keeping track of process identifiers by grouping behaviorally similar processes. Such an abstraction, while useful, conflicts with the notion of fairness. Because process identifiers are lost in the abstraction, it is difficult to ensure fairness (in terms of progress in executions) among the processes. In this work, we study the problem of fair model checking with process counter abstraction. Even without maintaining the process …

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Model Checking Linearizability Via Refinement, Yang Liu, Wei Chen, Yanhong A. Liu, Jun Sun Jun 2009

Model Checking Linearizability Via Refinement, Yang Liu, Wei Chen, Yanhong A. Liu, Jun Sun

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 be serializable, and 2) the serialized executions be correct with respect to the sequential semantics. This paper describes a new method to automatically check linearizability based on refinement relations from abstract specifications to concrete implementations. Our method avoids the often difficult task of determining linearization points in implementations, but can also take advantage of linearization points if they are given. The method exploits model checking of finite state systems specified as concurrent …

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Simplenpkl: Simple Non-Parametric Kernel Learning, Jinfeng Zhuang, Ivor Tsang, Steven C. H. Hoi Jun 2009

Simplenpkl: Simple Non-Parametric Kernel Learning, Jinfeng Zhuang, Ivor Tsang, Steven C. H. Hoi

Research Collection School Of Computing and Information Systems

Previous studies of Non-Parametric Kernel (NPK) learning usually reduce to solving some Semi-Definite Programming (SDP) problem by a standard SDP solver. However, time complexity of standard interior-point SDP solvers could be as high as O(n6.5). Such intensive computation cost prohibits NPK learning applicable to real applications, even for data sets of moderate size. In this paper, we propose an efficient approach to NPK learning from side information, referred to as SimpleNPKL, which can efficiently learn non-parametric kernels from large sets of pairwise constraints. In particular, we show that the proposed SimpleNPKL with linear loss has a closed-form solution that can …

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Nonrigid Shape Recovery By Gaussian Process Regression, Jianke Zhu, Steven C. H. Hoi, Michael R. Liu Jun 2009

Nonrigid Shape Recovery By Gaussian Process Regression, Jianke Zhu, Steven C. H. Hoi, Michael R. Liu

Research Collection School Of Computing and Information Systems

Most state-of-the-art nonrigid shape recovery methods usually use explicit deformable mesh models to regularize surface deformation and constrain the search space. These triangulated mesh models heavily relying on the quadratic regularization term are difficult to accurately capture large deformations, such as severe bending. In this paper, we propose a novel Gaussian process regression approach to the nonrigid shape recovery problem, which does not require to involve a predefined triangulated mesh model. By taking advantage of our novel Gaussian process regression formulation together with a robust coarse-to-fine optimization scheme, the proposed method is fully automatic and is able to handle large …

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Intentional Learning Agent Architecture, Budhitama Subagdja, Liz Sonenberg, Iyad Rahwan Jun 2009

Intentional Learning Agent Architecture, Budhitama Subagdja, Liz Sonenberg, Iyad Rahwan

Research Collection School Of Computing and Information Systems

Dealing with changing situations is a major issue in building agent systems. When the time is limited, knowledge is unreliable, and resources are scarce, the issue becomes more challenging. The BDI (Belief-Desire-Intention) agent architecture provides a model for building agents that addresses that issue. The model can be used to build intentional agents that are able to reason based on explicit mental attitudes, while behaving reactively in changing circumstances. However, despite the reactive and deliberative features, a classical BDI agent is not capable of learning. Plans as recipes that guide the activities of the agent are assumed to be static. …

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Mferio: The Design And Evaluation Of A Peer-To-Peer Mobile Payment System, Rajesh Krishna Balan, Narayanasamy Ramasubbu, Komsit Prakobphol, Nicolas Christin, Jason Hong Jun 2009

Mferio: The Design And Evaluation Of A Peer-To-Peer Mobile Payment System, Rajesh Krishna Balan, Narayanasamy Ramasubbu, Komsit Prakobphol, Nicolas Christin, Jason Hong

Research Collection School Of Computing and Information Systems

In this paper, we present the design and evaluation of a near-field communication-based mobile p2p payment application, called mFe-rio, that is designed to replace cash-based transactions. We first identify design criteria that payment systems should satisfy and then explain how mFerio, relative to those criteria, improves on the limitations of cash-based systems. We next describe mFerio's implementation and user interface design, focusing on the balance between usability and security. Finally, we present the results of a two-phase user study, involving a total of 104 people, that shows that mFerio has low cognitive load and is also fast, accurate, and easy …

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Adaptive In-Network Processing For Bandwidth And Energy Constrained Mission-Oriented Multi-Hop Wireless Networks, Sharanya Eswaran, Matthew Johnson, Archan Misra, Thomas La Porta Jun 2009

Adaptive In-Network Processing For Bandwidth And Energy Constrained Mission-Oriented Multi-Hop Wireless Networks, Sharanya Eswaran, Matthew Johnson, Archan Misra, Thomas La Porta

Research Collection School Of Computing and Information Systems

In-network processing, involving operations such as filtering, compression and fusion, is widely used in sensor networks to reduce the communication overhead. In many tactical and stream-oriented wireless network applications, both link bandwidth and node energy are critically constrained resources and in-network processing itself imposes non-negligible computing cost. In this work, we have developed a unified and distributed closed-loop control framework that computes both a) the optimal level of sensor stream compression performed by a forwarding node, and b) the best set of nodes where the stream processing operators should be deployed. Our framework extends the Network Utility Maximization (NUM) paradigm, …

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Non-Redundant Sequential Rules - Theory And Algorithm, David Lo, Siau-Cheng Khoo, Limsoon Wong Jun 2009

Non-Redundant Sequential Rules - Theory And Algorithm, David Lo, Siau-Cheng Khoo, Limsoon Wong

Research Collection School Of Computing and Information Systems

A sequential rule expresses a relationship between two series of events happening one after another. Sequential rules are potentially useful for analyzing data in sequential format, ranging from purchase histories, network logs and program execution traces. In this work, we investigate and propose a syntactic characterization of a non-redundant set of sequential rules built upon past work on compact set of representative patterns. A rule is redundant if it can be inferred from another rule having the same support and confidence. When using the set of mined rules as a composite filter, replacing a full set of rules with a …

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Information Sharing And Strategic Signaling In Supply Chains, Robert J. Kauffman, Hamid Mohtadi Jun 2009

Information Sharing And Strategic Signaling In Supply Chains, Robert J. Kauffman, Hamid Mohtadi

Research Collection School Of Computing and Information Systems

Information sharing in procurement occurs in rich and varied industry contexts in which managerial decisions are made and organizational strategy is formulated. We explore how information sharing ought to work in procurement contexts that involve investments in inter-organizational information systems (IOS) and collaborative planning, forecasting and replenishment (CPFR) practices. How and under what circumstances does a firm that plays the role of a supply chain buyer decide to share information on key variables, such as point-of-sale consumer demand data with its supplier, up the supply chain? This is a key issue that crosses the boundary between supply chain management and …

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Cyber Attacks: Cross-Country Interdependence And Enforcement, Qiu-Hong Wang, Seung Hyun Kim Jun 2009

Cyber Attacks: Cross-Country Interdependence And Enforcement, Qiu-Hong Wang, Seung Hyun Kim

Research Collection School Of Computing and Information Systems

This study empirically characterizes the interdependence in cyber attacks and examines theimpact from the first international treaty against cybercrimes (Convention on Cybercrimes:Europe Treaty Series No. 185). With the data covering 62 countries over the period from year2003 to 2007, we find that, international cooperation in enforcement as measured by theindicator of joining the Convention on Cybercrimes, deterred cyber attacks originating from anyparticular country by 15.81% ~ 24.77% (in 95% confidence interval). Second, joining theConvention also affected the interdependence in cyber attacks from two angels. First, for anypair of country, closer status in joining or not joining the Convention was associated …

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A Revisit Of Generative Model For Automatic Image Annotation Using Markov Random Fields, Yu Xiang, Xiangdong Zhou, Tat-Seng Chua, Chong-Wah Ngo Jun 2009

A Revisit Of Generative Model For Automatic Image Annotation Using Markov Random Fields, Yu Xiang, Xiangdong Zhou, Tat-Seng Chua, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

Much research effort on Automatic Image Annotation (AIA) has been focused on Generative Model, due to its well formed theory and competitive performance as compared with many well designed and sophisticated methods. However, when considering semantic context for annotation, the model suffers from the weak learning ability. This is mainly due to the lack of parameter setting and appropriate learning strategy for characterizing the semantic context in the traditional generative model. In this paper, we present a new approach based on Multiple Markov Random Fields (MRF) for semantic context modeling and learning. Differing from previous MRF related AIA approach, we …

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Interference-Aware Routing Protocol In Multi-Radio Wireless Mesh Networks, Byoungheon Shin, Yangwoo Ko, Jisun An, Dongman Lee Jun 2009

Interference-Aware Routing Protocol In Multi-Radio Wireless Mesh Networks, Byoungheon Shin, Yangwoo Ko, Jisun An, Dongman Lee

Research Collection School Of Computing and Information Systems

Utilization of multiple radio interfaces increases throughput of wireless networks. Existing work proposes a multi-radio routing protocol exploiting link quality and channel diversity of a path. While an established path is deteriorated by interferences incurred by any changes in a network, and existing work does not detect the deterioration. In this paper, we propose an interference-aware multi-radio routing protocol detecting and resolving dynamic path deterioration in wireless mesh networks.

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Applying Sanitizable Signature To Web-Service-Enabled Business Processes: Going Beyond Integrity Protection, Kar Way Tan, Robert H. Deng Jun 2009

Applying Sanitizable Signature To Web-Service-Enabled Business Processes: Going Beyond Integrity Protection, Kar Way Tan, Robert H. Deng

Research Collection School Of Computing and Information Systems

This paper studies the scenario where data in business documents is aggregated by different entities via the use of web services in streamlined business processes. The documents are transported within the Simple Object Access Protocol (SOAP) messages and travel through multiple intermediary entities, each potentially makes changes to the data in the documents. The WS-Security provides integrity protection by allowing portions of a SOAP message to be signed using eXtensible Markup Language (XML) signature scheme. This method however, has not considered the situation where a portion of data may be modified by another entity, therefore a need to allow the …

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Architectural Dualities In Complex Systems: Components, Interfaces, Technologies And Organizations, C. Jason Woodard, Joel West Jun 2009

Architectural Dualities In Complex Systems: Components, Interfaces, Technologies And Organizations, C. Jason Woodard, Joel West

Research Collection School Of Computing and Information Systems

Research on technological innovation and product development has long recognized the importance of product architecture, and many scholars have explored its relationship to the organizational structure of the product development process. Product architecture, in turn, has long encompassed both the allocation of functionality to components and the pattern of linkages between them. In this paper, we forge new connections among these established ideas by examining them as two pairs of dual relationships. First, we draw attention to the duality between components and interfaces. While innovation and product development researchers have historically emphasized the partitioning of products and systems into components, …

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A Formal Framework For Modeling And Validating Simulink Diagrams, Chunqing Chen, Jin Song Dong, Jun Sun May 2009

A Formal Framework For Modeling And Validating Simulink Diagrams, Chunqing Chen, Jin Song Dong, Jun Sun

Research Collection School Of Computing and Information Systems

Simulink has been widely used in industry to model and simulate embedded systems. With the increasing usage of embedded systems in real-time safety-critical situations, Simulink becomes deficient to analyze (timing) requirements with high-level assurance. In this article, we apply Timed Interval Calculus (TIC), a realtime specification language, to complement Simulink with TIC formal verification capability. We elaborately construct TIC library functions to model Simulink library blocks which are used to compose Simulink diagrams. Next, Simulink diagrams are automatically transformed into TIC models which preserve functional and timing aspects. Important requirements such as timing bounded liveness can be precisely specified in …

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Distributed Constraint Optimization With Structured Resource Constraints, Akshat Kumar, Boi Faltings, Adrian Petcu May 2009

Distributed Constraint Optimization With Structured Resource Constraints, Akshat Kumar, Boi Faltings, Adrian Petcu

Research Collection School Of Computing and Information Systems

Distributed constraint optimization (DCOP) provides a framework for coordinated decision making by a team of agents. Often, during the decision making, capacity constraints on agents' resource consumption must be taken into account. To address such scenarios, an extension of DCOP-Resource Constrained DCOP - has been proposed. However, certain type of resources have an additional structure associated with them and exploiting it can result in more efficient algorithms than possible with a general framework. An example of these are distribution networks, where the flow of a commodity from sources to sinks is limited by the flow capacity of edges. We present …

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Concernlines: A Timeline View Of Co-Occurring Concerns, Christoph Treude, Margaret-Anne Storey May 2009

Concernlines: A Timeline View Of Co-Occurring Concerns, Christoph Treude, Margaret-Anne Storey

Research Collection School Of Computing and Information Systems

Understanding the evolution of a software system requires understanding how information about the release history, non-functional requirements and project milestones relates to functional requirements on the software components. This short paper describes a new tool, called CONCERNLINES, that supports this cognitive process by visualizing co-occurring concerns over time.

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Zeros And Ones, M. Thulasidas May 2009

Zeros And Ones, M. Thulasidas

Research Collection School Of Computing and Information Systems

Computers are notorious for their infuriatingly literal obedience. I am sure anyone who has ever worked with a computer has come across the lack of empathy on its part – it follows our instructions to the dot, yet ends up accomplishing something altogether different from what we intend. Let’s spare a thought for the way your glorified adding machine makes sense of things

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A Self-Organizing Neural Network Architecture For Intentional Planning Agents, Budhitama Subagdja, Ah-Hwee Tan May 2009

A Self-Organizing Neural Network Architecture For Intentional Planning Agents, Budhitama Subagdja, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

This paper presents a model of neural network embodiment of intentions and planning mechanisms for autonomous agents. The model bridges the dichotomy of symbolic and non-symbolic representation in developing agents. Some novel techniques are introduced that enables the neural network to process and manipulate sequential and hierarchical structures of information. It is suggested that by incorporating intentional agent model which relies on explicit symbolic description with self-organizing neural networks that are good at learning and recognizing patterns, the best from both sides can be exploited. This paper demonstrates that plans can be represented as weighted connections and reasoning processes can …

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Classification Of Software Behaviors For Failure Detection: A Discriminative Pattern Mining Approach, David Lo, Hong Cheng, Jiawei Han, Siau-Cheng Khoo, Chengnian Sun May 2009

Classification Of Software Behaviors For Failure Detection: A Discriminative Pattern Mining Approach, David Lo, Hong Cheng, Jiawei Han, Siau-Cheng Khoo, Chengnian Sun

Research Collection School Of Computing and Information Systems

Software is a ubiquitous component of our daily life. We often depend on the correct working of software systems. Due to the difficulty and complexity of software systems, bugs and anomalies are prevalent. Bugs have caused billions of dollars loss, in addition to privacy and security threats. In this work, we address software reliability issues by proposing a novel method to classify software behaviors based on past history or runs. With the technique, it is possible to generalize past known errors and mistakes to capture failures and anomalies. Our technique first mines a set of discriminative features capturing repetitive series …

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