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I Tube, You Tube, Everybody Tubes: Analyzing The World’S Largest User Generated Content Video System, Meeyoung Cha, Haewoon Kwak, Pablo Rodriguez, Yong-Yeol Ahn, Sue. Moon Oct 2007

I Tube, You Tube, Everybody Tubes: Analyzing The World’S Largest User Generated Content Video System, Meeyoung Cha, Haewoon Kwak, Pablo Rodriguez, Yong-Yeol Ahn, Sue. Moon

Research Collection School Of Computing and Information Systems

User Generated Content (UGC) is re-shaping the way people watch video and TV, with millions of video producers and consumers. In particular, UGC sites are creating new viewing patterns and social interactions, empowering users to be more creative, and developing new business opportunities. To better understand the impact of UGC systems, we have analyzed YouTube, the world's largest UGC VoD system. Based on a large amount of data collected, we provide an in-depth study of YouTube and other similar UGC systems. In particular, we study the popularity life-cycle of videos, the intrinsic statistical properties of requests and their relationship with …

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Gapprox: Mining Frequent Approximate Patterns From A Massive Network, Chen Chen, Xifeng Yan, Feida Zhu, Jiawei Han Oct 2007

Gapprox: Mining Frequent Approximate Patterns From A Massive Network, Chen Chen, Xifeng Yan, Feida Zhu, Jiawei Han

Research Collection School Of Computing and Information Systems

Recently, there arise a large number of graphs with massive sizes and complex structures in many new applications, such as biological networks, social networks, and the Web, demanding powerful data mining methods. Due to inherent noise or data diversity, it is crucial to address the issue of approximation, if one wants to mine patterns that are potentially interesting with tolerable variations. In this paper, we investigate the problem of mining frequent approximate patterns from a massive network and propose a method called gApprox. gApprox not only finds approximate network patterns, which is the key for many knowledge discovery applications on …

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Efficient Discovery Of Frequent Approximate Sequential Patterns, Feida Zhu, Xifeng Yan, Jiawei Han, Philip S. Yu Oct 2007

Efficient Discovery Of Frequent Approximate Sequential Patterns, Feida Zhu, Xifeng Yan, Jiawei Han, Philip S. Yu

Research Collection School Of Computing and Information Systems

We propose an efficient algorithm for mining frequent approximate sequential patterns under the Hamming distance model. Our algorithm gains its efficiency by adopting a "break-down-and-build-up" methodology. The "breakdown" is based on the observation that all occurrences of a frequent pattern can be classified into groups, which we call strands. We developed efficient algorithms to quickly mine out all strands by iterative growth. In the "build-up" stage, these strands are grouped up to form the support sets from which all approximate patterns would be identified. A salient feature of our algorithm is its ability to grow the frequent patterns by iteratively …

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Mining Modal Scenarios From Execution Traces, David Lo, Shahar Maoz, Siau-Cheng Khoo Oct 2007

Mining Modal Scenarios From Execution Traces, David Lo, Shahar Maoz, Siau-Cheng Khoo

Research Collection School Of Computing and Information Systems

Specification mining is a dynamic analysis process aimed at automatically inferring suggested specifications of a program from its execution traces. We describe a method, a framework, and a tool, for mining inter-object scenario-based specifications in the form of a UML2-compliant variant of Damm and Harel's Live Sequence Charts (LSC), which extends the classical partial order semantics of sequence diagrams with temporal liveness and symbolic class level lifelines, in order to generate compact and expressive specifications. Moreover, we use previous research work and tools developed for LSC to visualize, analyze, manipulate, test, and thus evaluate the scenario-based specifications we mine. Our …

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Flexible Access Control To Jpeg 2000 Image Code-Streams, Yongdong Wu, Di Ma, Robert H. Deng Oct 2007

Flexible Access Control To Jpeg 2000 Image Code-Streams, Yongdong Wu, Di Ma, Robert H. Deng

Research Collection School Of Computing and Information Systems

JPEG 2000 is an international standard for still image compression in the 21st century. Part 8 of the standard, named JPSEC, is concerned with all the security aspects, in particular to access control and authentication. This paper presents a novel access control scheme for JPEG 2000 image code-streams. The proposed scheme is secure against collusion attacks and highly efficient. The scheme is also very flexible, allowing access control to JPEG 2000 image code-streams according to any combination of resolution, quality layer and region of interest. The "encrypt once, decrypt many ways" property of our scheme is designed to work seamlessly …

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A Multitude Of Opinions: Mining Online Rating Data, Hady Wirawan Lauw, Ee Peng Lim Oct 2007

A Multitude Of Opinions: Mining Online Rating Data, Hady Wirawan Lauw, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Online rating system is a popular feature of Web 2.0 applications. It typically involves a set of reviewers assigning rating scores (based on various evaluation criteria) to a set of objects. We identify two objectives for research on online rating data, namely achieving effective evaluation of objects and learning behaviors of reviewers/objects. These two objectives have conventionally been pursued separately. We argue that the future research direction should focus on the integration of these two objectives, as well as the integration between rating data and other types of data.

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Npake+: A Hierarchical Group Password-Authenticated Key Exchange Protocol Using Different Passwords, Zhiguo Wan, Robert H. Deng, Feng Bao, Bart Preneel Oct 2007

Npake+: A Hierarchical Group Password-Authenticated Key Exchange Protocol Using Different Passwords, Zhiguo Wan, Robert H. Deng, Feng Bao, Bart Preneel

Research Collection School Of Computing and Information Systems

Although two-party password-authenticated key exchange (PAKE) protocols have been intensively studied in recent years, group PAKE protocols have received little attention. In this paper, we propose a hierarchical group PAKE protocol nPAKE+ protocol under the setting where each party shares an independent password with a trusted server. The nPAKE+ protocol is a novel combination of the hierarchical key tree structure and the password-based Diffie-Hellman exchange, and hence it achieves substantial gain in computation efficiency. In particular, the computation cost for each client in our protocol is only O(logn). Additionally, the hierarchical feature of nPAKE+ enables every subgroup obtains their own …

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Performance Of Network-Coding In Multi-Rate Wireless Environments For Multicast Applications, Luiz F. M. Viera, Archan Misra, Mario Gerla Oct 2007

Performance Of Network-Coding In Multi-Rate Wireless Environments For Multicast Applications, Luiz F. M. Viera, Archan Misra, Mario Gerla

Research Collection School Of Computing and Information Systems

This paper investigates the interaction between net-work coding and link-layer transmission rate diversity in multi-hop wireless networks. By appropriately mixing data packets at intermediate nodes, network coding allows a single multicast flow to achieve higher throughput to a set of receivers. Broadcast applications can also exploit link-layer rate diversity, whereby individual nodes can transmit at faster rates at the expense of corresponding smaller coverage area. We first demonstrate how combining rate-diversity with network coding can provide a larger capacity for data dissemination of a single multicast flow, and how consideration of rate diversity is critical for maximizing system throughput. We …

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Sketchwizard: Wizard Of Oz Prototyping Of Pen-Based User Interfaces, Richard C. Davis, T. Scott Saponas, Michael Shilman, James A. Landay Oct 2007

Sketchwizard: Wizard Of Oz Prototyping Of Pen-Based User Interfaces, Richard C. Davis, T. Scott Saponas, Michael Shilman, James A. Landay

Research Collection School Of Computing and Information Systems

SketchWizard allows designers to create Wizard of Oz prototypes of pen-based user interfaces in the early stages of design. In the past, designers have been inhibited from participating in the design of pen-based interfaces because of the inadequacy of paper prototypes and the difficulty of developing functional prototypes. In SketchWizard, designers and end users share a drawing canvas between two computers, allowing the designer to simulate the behavior of recognition or other technologies. Special editing features are provided to help designers respond quickly to end-user input. This paper describes the SketchWizard system and presents two evaluations of our approach. The …

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Follow The Leader? Price Change Timing In Internet-Based Selling, R. J. Kauffman, Charles A. Wood Oct 2007

Follow The Leader? Price Change Timing In Internet-Based Selling, R. J. Kauffman, Charles A. Wood

Research Collection School Of Computing and Information Systems

Internet technologies should lessen information asymmetry, prompting competitive price reactions, but this does not seem to be happening in Internet-based selling. We study empirical regularities of price change timing for music CD vendors and booksellers to assess several theoretical explanations. Our sample includes 123, 680 daily prices for 169 products and 53 firms. Bertrand competition is insufficient to explain our observation that sellers do not shift prices this way. Tacitly collusive responses to competitors' price changes are observed rather than price changes solely in response to demand or cost shifts as would be expected with Bertrand competition. We find evidence …

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Option-Based Risk Management: A Field Study Of Sequential Information Technology Investment Decisions, Michel Benaroch, Mark Jeffery, Robert John Kauffman, Sandeep Shah Oct 2007

Option-Based Risk Management: A Field Study Of Sequential Information Technology Investment Decisions, Michel Benaroch, Mark Jeffery, Robert John Kauffman, Sandeep Shah

Research Collection School Of Computing and Information Systems

This field study research evaluates the viability of applying an option-based risk management (OBRiM) framework, and its accompanying theoretical perspective and methodology, to real-world sequential information technology (IT) investment problems. These problems involve alternative investment structures that bear different risk profiles for the firm, and also may improve the payoffs of the associated projects and the organization's performance. We sought to surface the costs, benefits, and risks associated with a complex sequential investment setting that has the key features that OBRiM treats. We combine traditional, purchased real options that subsequently create strategic flexibility for the decision maker, with implicit or …

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Supply Chain Excellence Is All About Providing, Knowledge@Smu Sep 2007

Supply Chain Excellence Is All About Providing, Knowledge@Smu

Knowledge@SMU

In a globalised economy, businesses are employing innovative methods to create value in the supply chain process. Operations, information and technology professor Hau L. Lee of Stanford University’s Graduate School of Business recently delivered a keynote address on “Creating Value with Supply Chain Excellence” at the Singapore Management University. Lee talked to Knowledge@SMU about how supply chain innovations could be developed and realised, using a framework he designed on Value-Creation Evolutions.

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Un-Balanced Economic Growth, Hing-Man Leung Sep 2007

Un-Balanced Economic Growth, Hing-Man Leung

Research Collection School Of Economics

Since the elasticity of substitution between capital and labor is not always one, and since technical progress is not always Harrod-neutral, it is desirable to have an endogenous growth model that admits all sizes of the elasticity and all known technology modes. We derive an equation to do just that, fully describing the per capita income growth rate at all times. It shows a typical economy needing hundreds if not thousands of years to reach its long term growth rate, leading to the conclusion that even the short run may be very long indeed.

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Novelty Detection For Cross-Lingual News Stories With Visual Duplicates And Speech Transcripts, Xiao Wu, Alexander G. Hauptmann, Chong-Wah Ngo Sep 2007

Novelty Detection For Cross-Lingual News Stories With Visual Duplicates And Speech Transcripts, Xiao Wu, Alexander G. Hauptmann, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

An overwhelming volume of news videos from different channels and languages is available today, which demands automatic management of this abundant information. To effectively search, retrieve, browse and track cross-lingual news stories, a news story similarity measure plays a critical role in assessing the novelty and redundancy among them. In this paper, we explore the novelty and redundancy detection with visual duplicates and speech transcripts for cross-lingual news stories. News stories are represented by a sequence of keyframes in the visual track and a set of words extracted from speech transcript in the audio track. A major difference to pure …

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A Self-Motives Perspective On Feedback-Seeking Behavior: Linking Organizational Behavior And Social Psychology Research, Frederick Anseel, Filip Lievens, Paul E. Levy Sep 2007

A Self-Motives Perspective On Feedback-Seeking Behavior: Linking Organizational Behavior And Social Psychology Research, Frederick Anseel, Filip Lievens, Paul E. Levy

Research Collection Lee Kong Chian School Of Business

Both the feedback-seeking literature in management and the self-motives domain in social psychology have focused on how motives affect the way in which people acquire information for self-evaluation purposes. Despite apparent conceptual similarities, the implications of research in these domains have not been fully integrated. This paper aims to link research on feedback-seeking behavior to recent theoretical developments in social psychology. First, the current perspective in management on feedback-seeking motives is depicted. Second, a well-established framework of self-motives in social psychology is introduced. Third, similarities and differences between these two motivational perspectives are discussed and a first step towards integration …

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Some Empirics On Economic Growth Under Heterogeneous Technology, Peter C. B. Phillips, Donggyu Sul Sep 2007

Some Empirics On Economic Growth Under Heterogeneous Technology, Peter C. B. Phillips, Donggyu Sul

Research Collection School Of Economics

A new econometric approach to testing for economic growth convergence is overviewed. The method is applicable to panel data, involves a simple regression based one-sided t-test, and can be used to form a clustering algorithm to assess the existence of growth convergence clubs. The approach allows for heterogeneous technology, utilizes some new asymptotic theory for nonlinear dynamic factor models, and is easy to implement. Some background growth theory is given which shows the form of augmented Solow regression (ASR) equations in the presence of heterogeneous technology and explains sources of potential misspecification that can arise in conventional formulations of ASR …

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Building Social Trust: A Human Capital Approach, Fali Huang Sep 2007

Building Social Trust: A Human Capital Approach, Fali Huang

Research Collection School Of Economics

Much evidence suggests individuals differ in their predisposition to cooperate, which is essentially a component of human capital. This paper examines the role of individual cooperative tendencies and their interactions with institutions in generating social trust; it also endogenizes cooperative tendencies using a human-capital investment model. Multiple equilibria and inefficiencies exist due to positive externalities. An innovative finding is that, when institutions are more effective in punishing defecting behaviors, more people invest in cooperative tendencies and hence the endogenous social trust is higher, though the equilibrium cooperative tendencies are lower. This paper provides a plausible explanation for many empirical and …

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Cross-Language And Cross-Media Image Retrieval: An Empirical Study At Imageclef2007, Steven C. H. Hoi Sep 2007

Cross-Language And Cross-Media Image Retrieval: An Empirical Study At Imageclef2007, Steven C. H. Hoi

Research Collection School Of Computing and Information Systems

This paper summarizes our empirical study of cross-language and cross-media image retrieval at the CLEF image retrieval track (ImageCLEF2007). In this year, we participated in the ImageCLEF photo retrieval task, in which the goal of the retrieval task is to search natural photos by some query with both textual and visual information. In this paper, we study the empirical evaluations of our solutions for the image retrieval tasks in three aspects. First of all, we study the application of language models and smoothing strategies for text-based image retrieval, particularly addressing the short text query issue. Secondly, we study the cross-media …

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Ntu: Solution For The Object Retrieval Task Of The Imageclef2007, Steven C. H. Hoi Sep 2007

Ntu: Solution For The Object Retrieval Task Of The Imageclef2007, Steven C. H. Hoi

Research Collection School Of Computing and Information Systems

Object retrieval is an interdisciplinary research problem between object recognition and content-based image retrieval (CBIR). It is commonly expected that object retrieval can be solved more effectively with the joint maximization of CBIR and object recognition techniques. We study a typical CBIR solution with application to the object retrieval tasks [26,27]. We expect that the empirical study in this work will serve as a baseline for future research when using CBIR techniques for object recognition.

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Overview Of The Imageclef 2007 Object Retrieval Task, Thomas Deselaers, Steven C. H. Hoi Sep 2007

Overview Of The Imageclef 2007 Object Retrieval Task, Thomas Deselaers, Steven C. H. Hoi

Research Collection School Of Computing and Information Systems

We describe the object retrieval task of ImageCLEF 2007, give an overview of the methods of the participating groups, and present and discuss the results. The task was based on the widely used PASCAL object recognition data to train object recognition methods and on the IAPR TC-12 benchmark dataset from which images of objects of the ten different classes bicycles, buses, cars, motorbikes, cats, cows, dogs, horses, sheep, and persons had to be retrieved. Seven international groups participated using a wide variety of methods. The results of the evaluation show that the task was very challenging and that different methods …

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Column Heterogeneity As A Measure Of Data Quality, Bing Tian Dai, Nick Koudas, Beng Chin Ooi, Divesh Srivastava, Suresh Venkatasubramanian Sep 2007

Column Heterogeneity As A Measure Of Data Quality, Bing Tian Dai, Nick Koudas, Beng Chin Ooi, Divesh Srivastava, Suresh Venkatasubramanian

Research Collection School Of Computing and Information Systems

Data quality is a serious concern in every data management application, and a variety of quality measures have been proposed, including accuracy, freshness and completeness, to capture the common sources of data quality degradation. We identify and focus attention on a novel measure, column heterogeneity, that seeks to quantify the data quality problems that can arise when merging data from different sources. We identify desiderata that a column heterogeneity measure should intuitively satisfy, and discuss a promising direction of research to quantify database column heterogeneity based on using a novel combination of cluster entropy and soft clustering. Finally, we present …

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Job Satisfaction As Mediator: An Assessment Of Job Satisfaction's Position Within The Nomological Network, Marcus Crede, Oleksandr S. Chernyshenko, Stephen Stark, Reeshad S. Dalal, Michael R. Bashshur Sep 2007

Job Satisfaction As Mediator: An Assessment Of Job Satisfaction's Position Within The Nomological Network, Marcus Crede, Oleksandr S. Chernyshenko, Stephen Stark, Reeshad S. Dalal, Michael R. Bashshur

Research Collection Lee Kong Chian School Of Business

Job satisfaction's position within the nomological network and the mechanism outlined by theories of social exchange suggest that job satisfaction functions as a mediator of the relationship between various antecedent variables and volitional workplace behaviours. We extend social exchange theory to include perceptions of the total job situation and develop a model that positions job satisfaction as a mediator of the relationships between various internal and external antecedent variables, and three volitional workplace behaviours: citizenship behaviours, counterproductive workplace behaviours, and job withdrawal. The fit of a fully mediated model is good and all four classes of antecedents (dispositions, workplace events, …

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Practical Elimination Of Near-Duplicates From Web Video Search, Xiao Wu, Alexander G. Hauptmann, Chong-Wah Ngo Sep 2007

Practical Elimination Of Near-Duplicates From Web Video Search, Xiao Wu, Alexander G. Hauptmann, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

Current web video search results rely exclusively on text keywords or user-supplied tags. A search on typical popular video often returns many duplicate and near-duplicate videos in the top results. This paper outlines ways to cluster and filter out the nearduplicate video using a hierarchical approach. Initial triage is performed using fast signatures derived from color histograms. Only when a video cannot be clearly classified as novel or nearduplicate using global signatures, we apply a more expensive local feature based near-duplicate detection which provides very accurate duplicate analysis through more costly computation. The results of 24 queries in a data …

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Context-Based Detection Of Clone-Related Bugs, Lingxiao Jiang, Zhendong Su, Edwin Chiu Sep 2007

Context-Based Detection Of Clone-Related Bugs, Lingxiao Jiang, Zhendong Su, Edwin Chiu

Research Collection School Of Computing and Information Systems

Studies show that programs contain much similar code, commonly known as clones. One of the main reasons for introducing clones is programmers' tendency to copy and paste code to quickly duplicate functionality. We commonly believe that clones can make programs difficult to maintain and introduce subtle bugs. Although much research has proposed techniques for detecting and removing clones to improve software maintainability, little has considered how to detect latent bugs introduced by clones. In this paper, we introduce a general notion of context-based inconsistencies among clones and develop an efficient algorithm to detect such inconsistencies for locating bugs. We have …

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Globally Distributed Software Development Project Performance: An Empirical Analysis, Narayanasamy Ramasubbu, Rajesh Krishna Balan Sep 2007

Globally Distributed Software Development Project Performance: An Empirical Analysis, Narayanasamy Ramasubbu, Rajesh Krishna Balan

Research Collection School Of Computing and Information Systems

Software firms are increasingly distributing their software development effort across multiple locations. In this paper we present the results of a two year field study that investigated the effects of dispersion on the productivity and quality of distributed software development. We first develop a model of distributed software development. We then use the model, along with our empirically observed data, to understand the consequences of dispersion on software project performance. Our analysis reveals that, even in high process maturity environments, a) dispersion significantly reduces development productivity and has effects on conformance quality, and b) these negative effects of dispersion can …

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The Soft Embodiment Of Culture: Camera Angles And Motion Through Time And Space, Angela K. Y. Leung, Dov Cohen Sep 2007

The Soft Embodiment Of Culture: Camera Angles And Motion Through Time And Space, Angela K. Y. Leung, Dov Cohen

Research Collection School of Social Sciences

Cultural assumptions about one's relation to others and one's place in the world can be literally embodied in the way one cognitively maps out one's position and motion in time and space. In three experiments, we examined the psychological perspective that Asian American and Euro-American participants embodied as they both comprehended and produced narratives and mapped out metaphors of time and space. In social situations, Euro-American participants were more likely to embody their own perspective and a sense of their own motion (rather than those of a friend), whereas Asian American participants were more likely to embody a friend's perspective …

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Evolutionary Combinatorial Optimization For Recursive Supervised Learning With Clustering, Kiruthika Ramanathan, Sheng Uei Guan Sep 2007

Evolutionary Combinatorial Optimization For Recursive Supervised Learning With Clustering, Kiruthika Ramanathan, Sheng Uei Guan

Research Collection School Of Computing and Information Systems

The idea of using a team of weak learners to learn a dataset is a successful one in literature. In this paper, we explore a recursive incremental approach to ensemble learning. In this paper, patterns are clustered according to the output space of the problem, i.e., natural clusters are formed based on patterns belonging to each class. A combinatorial optimization problem is therefore formed, which is solved using evolutionary algorithms. The evolutionary algorithms identify the "easy" and the "difficult" clusters in the system. The removal of the easy patterns then gives way to the focused learning of the more complicated …

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Anonymous And Authenticated Key Exchange For Roaming Networks, Guomin Yang, Duncan S. Wong, Xiaotie Deng Sep 2007

Anonymous And Authenticated Key Exchange For Roaming Networks, Guomin Yang, Duncan S. Wong, Xiaotie Deng

Research Collection School Of Computing and Information Systems

User privacy is a notable security issue in wireless communications. It concerns about user identities from being exposed and user movements and whereabouts from being tracked. The concern of user privacy is particularly signified in systems which support roaming when users are able to hop across networks administered by different operators. In this paper, we propose a novel construction approach of anonymous and authenticated key exchange protocols for a roaming user and a visiting server to establish a random session key in such a way that the visiting server authenticates the user's home server without knowing exactly who the user …

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Who’S Creating?, M. Thulasidas Sep 2007

Who’S Creating?, M. Thulasidas

Research Collection School Of Computing and Information Systems

We don’t read to retain information or knowledge any more. We search, scan, locate keywords, browse and bookmark. The Internet is doing to our reading habits what the calculator did to our arithmetic abilities. Knowledge is not cheap, although our easy access to it through the Internet may indicate otherwise. When we all become users of information, our knowledge will stop at its current level because nobody will be creating it any more.

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Keep The Talk Flowing, M. Thulasidas Sep 2007

Keep The Talk Flowing, M. Thulasidas

Research Collection School Of Computing and Information Systems

Specialisation is good. It lets us go deep into a specific field of endeavour, but at the expense of a broad overview of everything.

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