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Research Collection School Of Computing and Information Systems

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Articles 5821 - 5850 of 6891

Full-Text Articles in Physical Sciences and Mathematics

Localized Monitoring Of Knn Queries In Wireless Sensor Networks, Yuxia Yao, Xueyan Tang, Ee Peng Lim Jan 2009

Localized Monitoring Of Knn Queries In Wireless Sensor Networks, Yuxia Yao, Xueyan Tang, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Wireless sensor networks have been widely used in civilian and military applications. Primarily designed for monitoring purposes, many sensor applications require continuous collection and processing of sensed data. Due to the limited power supply for sensor nodes, energy efficiency is a major performance concern in query processing. In this paper, we focus on continuous kNN query processing in object tracking sensor networks. We propose a localized scheme to monitor nearest neighbors to a query point. The key idea is to establish a monitoring area for each query so that only the updates relevant to the query are collected. The monitoring …

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Ontology-Based Business Process Customization For Composite Web Services, Qianhui (Althea) Liang, Xindong Wu, E. K. Park, T. Khoshgoftaar, C. Chi Jan 2009

Ontology-Based Business Process Customization For Composite Web Services, Qianhui (Althea) Liang, Xindong Wu, E. K. Park, T. Khoshgoftaar, C. Chi

Research Collection School Of Computing and Information Systems

A key goal of the Semantic Web is to shift social interaction patterns from a producer-centric paradigm to a consumer-centric one. Treating customers as the most valuable assets and making the business models work better for them are at the core of building successful consumer-centric business models. It follows that customizing business processes constitutes a major concern in the realm of a knowledge-pull-based human semantic Web. This paper conceptualizes the customization of service-based business processes leveraging the existing knowledge of Web services and business processes. We represent this conceptualization as a new Extensible Markup Language (XML) markup language Web Ontology …

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Web Social Mining, Hady W. Lauw, Ee Peng Lim Jan 2009

Web Social Mining, Hady W. Lauw, Ee Peng Lim

Research Collection School Of Computing and Information Systems

No abstract provided.

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A Comprehensive Study For Rfid Malwares On Mobile Devices, Qiang Yan, Yingjiu Li, Tieyan Li, Robert Huijie Deng Jan 2009

A Comprehensive Study For Rfid Malwares On Mobile Devices, Qiang Yan, Yingjiu Li, Tieyan Li, Robert Huijie Deng

Research Collection School Of Computing and Information Systems

Radio Frequency Identification (RFID) technique has been widely accepted as wireless identification standard in the business world. While RFID technique enables efficient collection of identification information, it also introduces new security risk due to the emerging of RFID malwares. This risk becomes increasingly severe due to the adoption of internet in RFID applications (e.g., track and trace in EPCglobal network) and the use of mobile devices as RFID readers. The prior work to defend the threat of RFID malwares has mainly focused on the protection of front-end tag-reader communications and back-end database systems. Less work has been conducted to defend …

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Distributed Utility-Based Rate Adaptation Protocols For Prioritized, Quasi-Elastic Flows, Sharanya Eswaran, Matthew P. Johnson, Archan Misra, Thomas La Porta Jan 2009

Distributed Utility-Based Rate Adaptation Protocols For Prioritized, Quasi-Elastic Flows, Sharanya Eswaran, Matthew P. Johnson, Archan Misra, Thomas La Porta

Research Collection School Of Computing and Information Systems

This paper considers rate adaptation for streaming multimedia data in a wireless sensor network (WSN) consisting of multiple missions, where each mission subscribes to data streams from multiple sensors, and each sensor's data is utilized by multiple heterogenous missions. We specifically consider the application of the distributed network utility maximization (NUM) framework to a previously unconsidered scenario where the different missions have different priorities, as well as minimum utility demands. When all the utility demands are feasible, we first show that the addition of a penalty for failing to reach the minimum utility demand to the base NUM protocol leads …

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Multiuser Private Queries Over Encrypted Databases, Yanjiang Yang, Feng Bao, Xuhua Ding, Robert H. Deng Jan 2009

Multiuser Private Queries Over Encrypted Databases, Yanjiang Yang, Feng Bao, Xuhua Ding, Robert H. Deng

Research Collection School Of Computing and Information Systems

Searchable encryption schemes allow users to perform keyword-based searches on an encrypted database. Almost all existing such schemes only consider the scenario where a single user acts as both the data owner and the querier. However, most databases in practice do not just serve one user; instead, they support search and write operations by multiple users. In this paper, we systematically study searchable encryption in a practical multiuser setting. Our results include a set of security notions for multiuser searchable encryption as well as a construction which is provably secure under the newly introduced security notions. We also discuss how …

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Quc-Tree: Integrating Query Context Information For Efficient Music Retrieval, Jialie Shen, Dacheng Tao, Xuelong Li Jan 2009

Quc-Tree: Integrating Query Context Information For Efficient Music Retrieval, Jialie Shen, Dacheng Tao, Xuelong Li

Research Collection School Of Computing and Information Systems

In this paper, we introduce a novel indexing scheme-query context tree (QUC-tree) to facilitate efficient query sensitive music search under different query contexts. Distinguished from the previous approaches, QUC-tree is a balanced multiway tree structure, where each level represents the data space at different dimensionality. Before the tree structure construction, principle component analysis (PCA) is applied for data analysis and transforming the raw composite features into a new feature space sorted by the importance of acoustic features. The PCA transformed data and reduced dimensions in the upper levels can alleviate suffering from dimensionality curse. To accurately mimic human perception, an …

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Dynamic Web Service Selection For Reliable Web Service Composition, San-Yih Hwang, Ee Peng Lim, Chien-Hsiang Lee, Cheng-Hung Chen Jan 2009

Dynamic Web Service Selection For Reliable Web Service Composition, San-Yih Hwang, Ee Peng Lim, Chien-Hsiang Lee, Cheng-Hung Chen

Research Collection School Of Computing and Information Systems

This paper studies the dynamic web service selection problem in a failure-prone environment, which aims to determine a subset of Web services to be invoked at run-time so as to successfully orchestrate a composite web service. We observe that both the composite and constituent web services often constrain the sequences of invoking their operations and therefore propose to use finite state machine to model the permitted invocation sequences of Web service operations. We assign each state of execution an aggregated reliability to measure the probability that the given state will lead to successful execution in the context where each web …

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Tuning On-Air Signatures For Balancing Performance And Confidentiality, Baihua Zheng, Wang-Chien Lee, Peng Liu, Dik Lun Lee, Xuhua Ding Jan 2009

Tuning On-Air Signatures For Balancing Performance And Confidentiality, Baihua Zheng, Wang-Chien Lee, Peng Liu, Dik Lun Lee, Xuhua Ding

Research Collection School Of Computing and Information Systems

In this paper, we investigate the trade off between performance and confidentiality in signature-based air indexing schemes for wireless data broadcast. Two metrics, namely, false drop probability and false guess probability, are defined to quantify the filtering efficiency and confidentiality loss of a signature scheme. Our analysis reveals that false drop probability and false guess probability share a similar trend as the tuning parameters of a signature scheme change and it is impossible to achieve a low false drop probability and a high false guess probability simultaneously. In order to balance the performance and confidentiality, we perform an analysis to …

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The Price Of Stability In Selfish Scheduling Games, Lucas Agussurja, Hoong Chuin Lau Jan 2009

The Price Of Stability In Selfish Scheduling Games, Lucas Agussurja, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

Game theory has gained popularity as an approach to analysing and understanding distributed systems with self-interested agents. Central to game theory is the concept of Nash equilibrium as a stable state (solution) of the system, which comes with a price − the loss in efficiency. The quantification of the efficiency loss is one of the main research concerns. In this paper, we study the quality and computational characteristics of the best Nash equilibrium in two selfish scheduling models: the congestion model and the sequencing model. In particular, we present the following results: (1) In the congestion model: first, the best …

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Computing Medoids In Large Spatial Datasets, Kyriakos Mouratidis, Dimitris Papadias, Spiros Papadimitriou Jan 2009

Computing Medoids In Large Spatial Datasets, Kyriakos Mouratidis, Dimitris Papadias, Spiros Papadimitriou

Research Collection School Of Computing and Information Systems

In this chapter, we consider a class of queries that arise in spatial decision making and resource allocation applications. Assume that a company wants to open a number of warehouses in a city. Let P be the set of residential blocks in the city. P represents customer locations to be potentially served by the company. At the same time, P also comprises the candidate warehouse locations because the warehouses themselves must be opened in some residential blocks.

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Offering Rss Feeds: Does It Help To Gain Competitive Advantage?, Dan Ma Jan 2009

Offering Rss Feeds: Does It Help To Gain Competitive Advantage?, Dan Ma

Research Collection School Of Computing and Information Systems

Nowadays, many Websites have adopted the really simple syndication (RSS) technology to deliver online content to visitors. In this paper, I build an analytical model to examine how the offering of RSS feeds impact the number of visitors, total traffic load, and profit of Websites in a competitive setting. I show that although RSS can always attract more visitors, it may reduce the Website's profit. Interestingly, in a competitive market there are cases that the RSS feeds hurt the offering Website but benefit the competing Website instead. The conditions under which these will happen are derived. I also study the …

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Partially Materialized Digest Scheme: An Efficient Verification Method For Outsourced Databases, Kyriakos Mouratidis, Dimitris Sacharidis, Hwee Hwa Pang Jan 2009

Partially Materialized Digest Scheme: An Efficient Verification Method For Outsourced Databases, Kyriakos Mouratidis, Dimitris Sacharidis, Hwee Hwa Pang

Research Collection School Of Computing and Information Systems

In the outsourced database model, a data owner publishes her database through a third-party server; i.e., the server hosts the data and answers user queries on behalf of the owner. Since the server may not be trusted, or may be compromised, users need a means to verify that answers received are both authentic and complete, i.e., that the returned data have not been tampered with, and that no qualifying results have been omitted. We propose a result verification approach for one-dimensional queries, called Partially Materialized Digest scheme (PMD), that applies to both static and dynamic databases. PMD uses separate indexes …

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Efficient Valid Scope Computation For Location-Dependent Spatial Queries In Mobile And Wireless Environments, Ken C. K. Lee, Wang-Chien Lee, Hong Va Leong, Brandon Unger, Baihua Zheng Jan 2009

Efficient Valid Scope Computation For Location-Dependent Spatial Queries In Mobile And Wireless Environments, Ken C. K. Lee, Wang-Chien Lee, Hong Va Leong, Brandon Unger, Baihua Zheng

Research Collection School Of Computing and Information Systems

In mobile and wireless environments, mobile clients can access information with respect to their locations by submitting Location-Dependent Spatial Queries (LDSQs) to Location-Based Service (LBS) servers. Owing to scarce wireless channel bandwidth and limited client battery life, frequent LDSQ submission from clients must be avoided. Observing that LDSQs issued from similar client positions would normally return the same results, we explore the idea of valid scope, that represents a spatial area in which a set of LDSQs will retrieve exactly the same query results. With a valid scope derived and an LDSQ result cached at the client side, a client …

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Quality-Aware Collaborative Question Answering: Methods And Evaluation, Maggy Anastasia Suryanto, Ee Peng Lim, Aixin Sun, Roger Hsiang-Li Chiang Jan 2009

Quality-Aware Collaborative Question Answering: Methods And Evaluation, Maggy Anastasia Suryanto, Ee Peng Lim, Aixin Sun, Roger Hsiang-Li Chiang

Research Collection School Of Computing and Information Systems

Community Question Answering (QA) portals contain questions and answers contributed by hundreds of millions of users. These databases of questions and answers are of great value if they can be used directly to answer questions from any user. In this research, we address this collaborative QA task by drawing knowledge from the crowds in community QA portals such as Yahoo! Answers. Despite their popularity, it is well known that answers in community QA portals have unequal quality. We therefore propose a quality-aware framework to design methods that select answers from a community QA portal considering answer quality in addition to …

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When Is It Beneficial For A Firm To Pursue A Unified Procurement Strategy For Enterprise Software Solutions?, Robert J. Kauffman, Juliana Y. Tsai Jan 2009

When Is It Beneficial For A Firm To Pursue A Unified Procurement Strategy For Enterprise Software Solutions?, Robert J. Kauffman, Juliana Y. Tsai

Research Collection School Of Computing and Information Systems

The underlying structure of the enterprise software marketplace during the past ten years suggests that the arrangements that firms make with respect to the acquisition of such software capabilities will become increasingly concentrated. This article explores the multiple theoretical rationales and business cases for the move to a unified procurement strategy for enterprise software, reflecting some differences in terms of what might be expected from the predictions of the well known move-to-the-middle hypothesis. Our central argument is that a "move-to-the-middle" with more than just a single vendor is the likely outcome in unconsolidated industry markets. In industries experiencing consolidation, firms …

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Event-Detecting Multi-Agent Mdps: Complexity And Constant-Factor Approximation, Akshat Kumar, S. Zilberstein Jan 2009

Event-Detecting Multi-Agent Mdps: Complexity And Constant-Factor Approximation, Akshat Kumar, S. Zilberstein

Research Collection School Of Computing and Information Systems

Planning under uncertainty for multiple agents has grown rapidly with the development of formal models such as multi-agent MDPs and decentralized MDPs. But despite their richness, the applicability of these models remains limited due to their computational complexity. We present the class of event-detecting multi-agent MDPs (eMMDPs), designed to detect multiple mobile targets by a team of sensor agents. We show that eMMDPs are NP-Hard and present a scalable 2-approximation algorithm for solving them using matroid theory and constraint optimization. The complexity of the algorithm is linear in the state-space and number of agents, quadratic in the horizon, and exponential …

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The Architecture Of Platforms: A Unified View, Carliss Y. Baldwin, C. Jason Woodard Jan 2009

The Architecture Of Platforms: A Unified View, Carliss Y. Baldwin, C. Jason Woodard

Research Collection School Of Computing and Information Systems

Product and system designers have long exploited opportunities to create families of complex artifacts by developing and recombining modular components. An especially common design pattern has come to be associated with the concept of a ‘platform’, which we define as a set of stable components that supports variety and evolvability in a system by constraining the linkages among the other components. Our goal in this chapter is to shed light on the relationships between platforms and the systems in which they are embedded, in order to better understand firms and industries where platforms play an important role. We begin by …

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Chaos And Uncertainty, M. Thulasidas Jan 2009

Chaos And Uncertainty, M. Thulasidas

Research Collection School Of Computing and Information Systems

The end of 2008 in the finance industry can be summarized in two words – chaos and uncertainty. The subprime crisis, where everybody lost; the dizzying commodity price movements; the pink slip syndrome; the spectacular bank busts; and the gargantuan bail-outs all vouch for it.

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Text Mining In Radiology Reports, Tianxia Gong, Chew Lim Tan, Tze-Yun Leong, Cheng Kiang Lee, Boon Chuan Pang, C. C. Tchoyoson Lim, Qi Tian, Suisheng Tang, Zhuo Zhang Dec 2008

Text Mining In Radiology Reports, Tianxia Gong, Chew Lim Tan, Tze-Yun Leong, Cheng Kiang Lee, Boon Chuan Pang, C. C. Tchoyoson Lim, Qi Tian, Suisheng Tang, Zhuo Zhang

Research Collection School Of Computing and Information Systems

Medical text mining has gained increasing interest in recent years. Radiology reports contain rich information describing radiologist's observations on the patient's medical conditions in the associated medical images. However as most reports are in free text format, the valuable information contained in those reports cannot be easily accessed and used, unless proper text mining has been applied. In this paper we propose a text mining system to extract and use the information in radiology reports. The system consists of three main modules: a medical finding extractor a report and image retriever and a text-assisted image feature extractor In evaluation, the …

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Ambiguous Optimistic Fair Exchange, Qiong Huang, Guomin Yang, Duncan S. Wong, Willy Susilo Dec 2008

Ambiguous Optimistic Fair Exchange, Qiong Huang, Guomin Yang, Duncan S. Wong, Willy Susilo

Research Collection School Of Computing and Information Systems

Optimistic fair exchange (OFE) is a protocol for solving the problem of exchanging items or services in a fair manner between two parties, a signer and a verifier, with the help of an arbitrator which is called in only when a dispute happens between the two parties. In almost all the previous work on OFE, after obtaining a partial signature from the signer, the verifier can present it to others and show that the signer has indeed committed itself to something corresponding to the partial signature even prior to the completion of the transaction. In some scenarios, this capability given …

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On Visualizing Heterogeneous Semantic Networks From Multiple Data Sources, Maureen Maureen, Aixin Sun, Ee Peng Lim, Anwitaman Datta, Kuiyu Chang Dec 2008

On Visualizing Heterogeneous Semantic Networks From Multiple Data Sources, Maureen Maureen, Aixin Sun, Ee Peng Lim, Anwitaman Datta, Kuiyu Chang

Research Collection School Of Computing and Information Systems

In this paper, we focus on the visualization of heterogeneous semantic networks obtained from multiple data sources. A semantic network comprising a set of entities and relationships is often used for representing knowledge derived from textual data or database records. Although the semantic networks created for the same domain at different data sources may cover a similar set of entities, these networks could also be very different because of naming conventions, coverage, view points, and other reasons. Since digital libraries often contain data from multiple sources, we propose a visualization tool to integrate and analyze the differences among multiple social …

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Cognitive Agents Integrating Rules And Reinforcement Learning For Context-Aware Decision Support, Teck-Hou Teng, Ah-Hwee Tan Dec 2008

Cognitive Agents Integrating Rules And Reinforcement Learning For Context-Aware Decision Support, Teck-Hou Teng, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

While context-awareness has been found to be effective for decision support in complex domains, most of such decision support systems are hard-coded, incurring significant development efforts. To ease the knowledge acquisition bottleneck, this paper presents a class of cognitive agents based on self-organizing neural model known as TD-FALCON that integrates rules and learning for supporting context-aware decision making. Besides the ability to incorporate a priori knowledge in the form of symbolic propositional rules, TD-FALCON performs reinforcement learning (RL), enabling knowledge refinement and expansion through the interaction with its environment. The efficacy of the developed Context-Aware Decision Support (CaDS) system is …

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Text Cube: Computing Ir Measures For Multidimensional Text Database Analysis, Cindy Xinde Lin, Bolin Ding, Jiawei Han, Feida Zhu, Bo Zhao Dec 2008

Text Cube: Computing Ir Measures For Multidimensional Text Database Analysis, Cindy Xinde Lin, Bolin Ding, Jiawei Han, Feida Zhu, Bo Zhao

Research Collection School Of Computing and Information Systems

Since Jim Gray introduced the concept of ”data cube” in 1997, data cube, associated with online analytical processing (OLAP), has become a driving engine in data warehouse industry. Because the boom of Internet has given rise to an ever increasing amount of text data associated with other multidimensional information, it is natural to propose a data cube model that integrates the power of traditional OLAP and IR techniques for text. In this paper, we propose a Text-Cube model on multidimensional text database and study effective OLAP over such data. Two kinds of hierarchies are distinguishable inside: dimensional hierarchy and term …

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Making Sense Of Technology Trends In The Information Technology Landscape, Gediminas Adomavicius, Jesse C. Bockstedt, Alok Gupta, Robert J. Kauffman Dec 2008

Making Sense Of Technology Trends In The Information Technology Landscape, Gediminas Adomavicius, Jesse C. Bockstedt, Alok Gupta, Robert J. Kauffman

Research Collection School Of Computing and Information Systems

A major problem for firms making information technology investment decisions is predicting and understanding the effects of future technological developments on the value of present technologies. Failure to adequately address this problem can result in wasted organization resources in acquiring, developing, managing, and training employees in the use of technologies that are short-lived and fail to produce adequate return on investment. The sheer number of available technologies and the complex set of relationships among them make IT landscape analysis extremely challenging. Most IT-consuming firms rely on third parties and suppliers for strategic recommendations on IT investments, which can lead to …

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Planning With Ifalcon: Towards A Neural-Network-Based Bdi Agent Architecture, Budhitama Subagdja, Ah-Hwee Tan Dec 2008

Planning With Ifalcon: Towards A Neural-Network-Based Bdi Agent Architecture, Budhitama Subagdja, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

This paper presents iFALCON, a model of BDI (beliefdesire-intention) agents that is fully realized as a selforganizing neural network architecture. Based on multichannel network model called fusion ART, iFALCON is developed to bridge the gap between a self-organizing neural network that autonomously adapts its knowledge and the BDI agent model that follows explicit descriptions. Novel techniques called gradient encoding are introduced for representing sequences and hierarchical structures to realize plans and the intention structure. This paper shows that a simplified plan representation can be encoded as weighted connections in the neural network through a process of supervised learning. A case …

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A Fast Pruned‐Extreme Learning Machine For Classification Problem, Hai-Jun Rong, Yew-Soon Ong, Ah-Hwee Tan, Zexuan Zhu Dec 2008

A Fast Pruned‐Extreme Learning Machine For Classification Problem, Hai-Jun Rong, Yew-Soon Ong, Ah-Hwee Tan, Zexuan Zhu

Research Collection School Of Computing and Information Systems

Extreme learning machine (ELM) represents one of the recent successful approaches in machine learning, particularly for performing pattern classification. One key strength of ELM is the significantly low computational time required for training new classifiers since the weights of the hidden and output nodes are randomly chosen and analytically determined, respectively. In this paper, we address the architectural design of the ELM classifier network, since too few/many hidden nodes employed would lead to underfitting/overfitting issues in pattern classification. In particular, we describe the proposed pruned-ELM (P-ELM) algorithm as a systematic and automated approach for designing ELM classifier network. P-ELM uses …

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Distributing Complementary Resources Across Multiple Periods With Stochastic Demand, Shih-Fen Cheng, John Tajan, Hoong Chuin Lau Dec 2008

Distributing Complementary Resources Across Multiple Periods With Stochastic Demand, Shih-Fen Cheng, John Tajan, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

In this paper, we evaluate whether the robustness of a market mechanism that allocates complementary resources could be improved through the aggregation of time periods in which resources are consumed. In particular, we study a multi-round combinatorial auction that is built on a general equilibrium framework. We adopt the general equilibrium framework and the particular combinatorial auction design from the literature, and we investigate the benefits and the limitation of time-period aggregation when demand-side uncertainties are introduced. By using simulation experiments, we show that under stochastic conditions the performance variation of the process decreases as the time frame length (time …

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Chosen-Ciphertext Secure Proxy Re-Encryption Without Pairing, Robert H. Deng, Jian Weng, Shengli Liu, Kefei Chen Dec 2008

Chosen-Ciphertext Secure Proxy Re-Encryption Without Pairing, Robert H. Deng, Jian Weng, Shengli Liu, Kefei Chen

Research Collection School Of Computing and Information Systems

In a proxy re-encryption system, a semi-trusted proxy can convert a ciphertext originally intended for Alice into a ciphertext intended for Bob, without learning the underlying plaintext. Proxy re-encryption has found many practical applications, such as encrypted email forwarding, secure distributed file systems, and outsourced filtering of encrypted spam. In ACM CCS'07, Canetti and Hohenberger presented a proxy re-encryption scheme with chosen-ciphertext security, and left an important open problem to construct a chosen-ciphertext secure proxy re-encryption scheme without pairings. In this paper, we solve this open problem by proposing a new proxy re-encryption scheme without resort to bilinear pairings. Based …

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Mobitop: Accessing Hierarchically Organized Georeferenced Multimedia Annotations, Thi Nhu Quynh Kim, Khasfariyati Razikin, Dion Hoe-Lian Goh, Quang Minh Nguyen, Ee Peng Lim Dec 2008

Mobitop: Accessing Hierarchically Organized Georeferenced Multimedia Annotations, Thi Nhu Quynh Kim, Khasfariyati Razikin, Dion Hoe-Lian Goh, Quang Minh Nguyen, Ee Peng Lim

Research Collection School Of Computing and Information Systems

We introduce MobiTOP, a map-based interface for accessing hierarchically organized georeferenced annotations. Each annotation contains multimedia content associated with a location, and users are able to annotate existing annotations, in effect creating a hierarchy.

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