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Showing papers by "IBM published in 2003"


Journal ArticleDOI
Jeffrey O. Kephart1, David M. Chess1
TL;DR: A 2001 IBM manifesto noted the almost impossible difficulty of managing current and planned computing systems, which require integrating several heterogeneous environments into corporate-wide computing systems that extend into the Internet.
Abstract: A 2001 IBM manifesto observed that a looming software complexity crisis -caused by applications and environments that number into the tens of millions of lines of code - threatened to halt progress in computing. The manifesto noted the almost impossible difficulty of managing current and planned computing systems, which require integrating several heterogeneous environments into corporate-wide computing systems that extend into the Internet. Autonomic computing, perhaps the most attractive approach to solving this problem, creates systems that can manage themselves when given high-level objectives from administrators. Systems manage themselves according to an administrator's goals. New components integrate as effortlessly as a new cell establishes itself in the human body. These ideas are not science fiction, but elements of the grand challenge to create self-managing computing systems.

6,527 citations


Book ChapterDOI
04 May 2003
TL;DR: This work introduces captcha, an automated test that humans can pass, but current computer programs can't pass; any program that has high success over a captcha can be used to solve an unsolved Artificial Intelligence (AI) problem; and provides several novel constructions of captchas, which imply a win-win situation.
Abstract: We introduce captcha, an automated test that humans can pass, but current computer programs can't pass: any program that has high success over a captcha can be used to solve an unsolved Artificial Intelligence (AI) problem. We provide several novel constructions of captchas. Since captchas have many applications in practical security, our approach introduces a new class of hard problems that can be exploited for security purposes. Much like research in cryptography has had a positive impact on algorithms for factoring and discrete log, we hope that the use of hard AI problems for security purposes allows us to advance the field of Artificial Intelligence. We introduce two families of AI problems that can be used to construct captchas and we show that solutions to such problems can be used for steganographic communication. captchas based on these AI problem families, then, imply a win-win situation: either the problems remain unsolved and there is a way to differentiate humans from computers, or the problems are solved and there is a way to communicate covertly on some channels.

1,525 citations


Proceedings ArticleDOI
24 Aug 2003
TL;DR: This paper proposes a general framework for mining concept-drifting data streams using weighted ensemble classifiers, and shows that the proposed methods have substantial advantage over single-classifier approaches in prediction accuracy, and the ensemble framework is effective for a variety of classification models.
Abstract: Recently, mining data streams with concept drifts for actionable insights has become an important and challenging task for a wide range of applications including credit card fraud protection, target marketing, network intrusion detection, etc. Conventional knowledge discovery tools are facing two challenges, the overwhelming volume of the streaming data, and the concept drifts. In this paper, we propose a general framework for mining concept-drifting data streams using weighted ensemble classifiers. We train an ensemble of classification models, such as C4.5, RIPPER, naive Beyesian, etc., from sequential chunks of the data stream. The classifiers in the ensemble are judiciously weighted based on their expected classification accuracy on the test data under the time-evolving environment. Thus, the ensemble approach improves both the efficiency in learning the model and the accuracy in performing classification. Our empirical study shows that the proposed methods have substantial advantage over single-classifier approaches in prediction accuracy, and the ensemble framework is effective for a variety of classification models.

1,403 citations


Journal ArticleDOI
TL;DR: An elegant and remarkably simple algorithm ("the threshold algorithm", or TA) is analyzed that is optimal in a much stronger sense than FA, and is essentially optimal, not just for some monotone aggregation functions, but for all of them, and not just in a high-probability worst-case sense, but over every database.

1,315 citations


Journal ArticleDOI
Bran Selic1
TL;DR: The key lies in resolving pragmatic issues related to the artifacts and culture of the previous generation of software technologies that have rarely produced anticipated benefits.
Abstract: The potential benefits of using models are significantly greater in software than in other engineering disciplines because of the potential for a seamless link between models and the systems they represent. Unfortunately, models have rarely produced anticipated benefits. The key lies in resolving pragmatic issues related to the artifacts and culture of the previous generation of software technologies.

1,293 citations


Proceedings ArticleDOI
20 May 2003
TL;DR: This paper proposes a global planning approach to optimally select component services during the execution of a composite service, and experimental results show that thisglobal planning approach outperforms approaches in which the component services are selected individually for each task in a Composite service.
Abstract: The process-driven composition of Web services is emerging as a promising approach to integrate business applications within and across organizational boundaries. In this approach, individual Web services are federated into composite Web services whose business logic is expressed as a process model. The tasks of this process model are essentially invocations to functionalities offered by the underlying component services. Usually, several component services are able to execute a given task, although with different levels of pricing and quality. In this paper, we advocate that the selection of component services should be carried out during the execution of a composite service, rather than at design-time. In addition, this selection should consider multiple criteria (e.g., price, duration, reliability), and it should take into account global constraints and preferences set by the user (e.g., budget constraints). Accordingly, the paper proposes a global planning approach to optimally select component services during the execution of a composite service. Service selection is formulated as an optimization problem which can be solved using efficient linear programming methods. Experimental results show that this global planning approach outperforms approaches in which the component services are selected individually for each task in a composite service.

1,229 citations


Proceedings ArticleDOI
24 Aug 2003
TL;DR: This work presents an innovative co-clustering algorithm that monotonically increases the preserved mutual information by intertwining both the row and column clusterings at all stages and demonstrates that the algorithm works well in practice, especially in the presence of sparsity and high-dimensionality.
Abstract: Two-dimensional contingency or co-occurrence tables arise frequently in important applications such as text, web-log and market-basket data analysis. A basic problem in contingency table analysis is co-clustering: simultaneous clustering of the rows and columns. A novel theoretical formulation views the contingency table as an empirical joint probability distribution of two discrete random variables and poses the co-clustering problem as an optimization problem in information theory---the optimal co-clustering maximizes the mutual information between the clustered random variables subject to constraints on the number of row and column clusters. We present an innovative co-clustering algorithm that monotonically increases the preserved mutual information by intertwining both the row and column clusterings at all stages. Using the practical example of simultaneous word-document clustering, we demonstrate that our algorithm works well in practice, especially in the presence of sparsity and high-dimensionality.

1,203 citations


Journal ArticleDOI
C. F. Kurtz1, David J. Snowden1
TL;DR: This publication contains reprint articles for which IEEE does not hold copyright and which are likely to be copyrighted.
Abstract: In this paper, we challenge the universality of three basic assumptions prevalent in organizational decision support and strategy: assumptions of order, of rational choice, and of intent. We describe the Cynefin framework, a sense-making device we have developed to help people make sense of the complexities made visible by the relaxation of these assumptions. The Cynefin framework is derived from several years of action research into the use of narrative and complexity theory in organizational knowledge exchange, decision-making, strategy, and policy-making. The framework is explained, its conceptual underpinnings are outlined, and its use in group sense-making and discourse is described. Finally, the consequences of relaxing the three basic assumptions, using the Cynefin framework as a mechanism, are considered.

1,152 citations


Proceedings ArticleDOI
Tetsuya Nasukawa1, Jeonghee Yi1
23 Oct 2003
TL;DR: This paper illustrates a sentiment analysis approach to extract sentiments associated with polarities of positive or negative for specific subjects from a document, instead of classifying the whole document intopositive or negative.
Abstract: This paper illustrates a sentiment analysis approach to extract sentiments associated with polarities of positive or negative for specific subjects from a document, instead of classifying the whole document into positive or negative.The essential issues in sentiment analysis are to identify how sentiments are expressed in texts and whether the expressions indicate positive (favorable) or negative (unfavorable) opinions toward the subject. In order to improve the accuracy of the sentiment analysis, it is important to properly identify the semantic relationships between the sentiment expressions and the subject. By applying semantic analysis with a syntactic parser and sentiment lexicon, our prototype system achieved high precision (75-95%, depending on the data) in finding sentiments within Web pages and news articles.

1,144 citations


Journal ArticleDOI
Alexander Keller1, Heiko Ludwig1
TL;DR: A novel framework for specifying and monitoring Service Level Agreements (SLA) for Web Services, designed for a Web Services environment, that is applicable as well to any inter-domain management scenario, such as business process and service management, or the management of networks, systems and applications in general.
Abstract: We describe a novel framework for specifying and monitoring Service Level Agreements (SLA) for Web Services. SLA monitoring and enforcement become increasingly important in a Web Service environment where enterprise applications and services rely on services that may be subscribed dynamically and on-demand. For economic and practical reasons, we want an automated provisioning process for both the service itself as well as the SLA managment system that measures and monitors the QoS parameters, checks the agreed-upon service levels, and reports violations to the authorized parties involved in the SLA management process. Our approach to these issues is presented in this paper. The Web Service Level Agreement (WSLA) framework is targeted at defining and monitoring SLAs for Web Services. Although WSLA has been designed for a Web Services environment, it is applicable as well to any inter-domain management scenario, such as business process and service management, or the management of networks, systems and applications in general. The WSLA framework consists of a flexible and extensible language based on XML Schema and a runtime architecture comprising several SLA monitoring services, which may be outsourced to third parties to ensure a maximum of objectivity. WSLA enables service customers and providers to unambiguously define a wide variety of SLAs, specify the SLA parameters and the way they are measured, and relate them to managed resource instrumentations. Upon receipt of an SLA specification, the WSLA monitoring services are automatically configured to enforce the SLA. An implementation of the WSLA framework, termed SLA Compliance Monitor, is publicly available as part of the IBM Web Services Toolkit.

1,036 citations


Journal ArticleDOI
D. Porcino1, W. Hirt2
TL;DR: The application potential and technical challenges presented by UWB radio as an unconventional but promising new wireless technology are discussed, with the potential to provide solutions for many of today's problems in the areas of spectrum management and radio system engineering.
Abstract: An unprecedented transformation in the design, deployment, and application of short-range wireless devices and services is in progress today. This trend is in line with the imminent transition from third- to fourth-generation radio systems, where heterogeneous environments are expected to prevail eventually. A key driver in this transition is the steep growth in both demand and deployment of WLANs/WPANs based on the wireless standards within the IEEE 802 suite. Today, these short-range devices and networks operate mainly standalone in indoor home and office environments or large enclosed public areas, while their integration into the wireless wide-area infrastructure is still nearly nonexistent and far from trivial. This status quo in the short-range wireless application space is about to be disrupted by novel devices and systems based on the emerging UWB radio technology with the potential to provide solutions for many of today's problems in the areas of spectrum management and radio system engineering. The approach employed by UWB radio devices is based on sharing already occupied spectrum resources by means of the overlay principle, rather than looking for still available but possibly unsuitable new bands. This novel radio technology has received legal adoption by the regulatory authorities in the United States, and efforts to achieve this status in Europe and Asia are underway. This article discusses both the application potential and technical challenges presented by UWB radio as an unconventional but promising new wireless technology.

Patent
22 Oct 2003
TL;DR: In this article, the recovery process ensures that the recovered repository is consistent with the state of the repository at the time of the failure, but is available for addition and retrieval of new data items before completion of the recovery processing.
Abstract: Provided are methods, data processing systems, recovery components and computer programs for recovering from storage failures affecting data repositories. At least a part of the recovery processing is performed while the data repositories are able to receive new data and to allow retrieval of such new data. Although new data items may be received into the repository and retrieved therefrom during recovery processing, updates to the data repository which were performed before the failure and which are then restored to the repository by the recovery processing are restored within a recovery unit of work and are inaccessible to processes other than the recovery process until successful completion of the recovery unit of work. The recovery processing ensures that the recovered repository is consistent with the state of the repository at the time of the failure, but is available for addition and retrieval of new data items before completion of the recovery processing.

Journal ArticleDOI
01 Mar 2003
TL;DR: In some applications, biometrics can replace or supplement the existing technology and in others, it is the only viable approach.
Abstract: Biometrics offers greater security and convenience than traditional methods of personal recognition. In some applications, biometrics can replace or supplement the existing technology. In others, it is the only viable approach. But how secure is biometrics? And what are the privacy implications?.

Journal ArticleDOI
TL;DR: The current status of basic electron transfer research, both theoretical and experimental, with emphasis on the distance-dependent measurements, was discussed in this article, where the authors attempted to integrate terminology and notation of solution electron-transfer kinetics with that of conductance analysis.
Abstract: This is the report of a DOE-sponsored workshop organized to discuss the status of our understanding of charge-transfer processes on the nanoscale and to identify research and other needs for progress in nanoscience and nanotechnology. The current status of basic electron-transfer research, both theoretical and experimental, is addressed, with emphasis on the distance-dependent measurements, and we have attempted to integrate terminology and notation of solution electron-transfer kinetics with that of conductance analysis. The interface between molecules or nanoparticles and bulk metals is examined, and new research tools that advance description and understanding of the interface are presented. The present state-of-the-art in molecular electronics efforts is summarized along with future research needs. Finally, novel strategies that exploit nanoscale architectures are presented for enhancing the efficiences of energy conversion based on photochemistry, catalysis, and electrocatalysis principles.

Proceedings Article
Nimrod Megiddo1, Dharmendra S. Modha1
31 Mar 2003
TL;DR: The problem of cache management in a demand paging scenario with uniform page sizes is considered and a new cache management policy, namely, Adaptive Replacement Cache (ARC), is proposed that has several advantages.
Abstract: We consider the problem of cache management in a demand paging scenario with uniform page sizes. We propose a new cache management policy, namely, Adaptive Replacement Cache (ARC), that has several advantages. In response to evolving and changing access patterns, ARC dynamically, adaptively, and continually balances between the recency and frequency components in an online and selftuning fashion. The policy ARC uses a learning rule to adaptively and continually revise its assumptions about the workload. The policy ARC is empirically universal, that is, it empirically performs as well as a certain fixed replacement policy-even when the latter uses the best workload-specific tuning parameter that was selected in an offline fashion. Consequently, ARC works uniformly well across varied workloads and cache sizes without any need for workload specific a priori knowledge or tuning. Various policies such as LRU-2, 2Q, LRFU, and LIRS require user-defined parameters, and, unfortunately, no single choice works uniformly well across different workloads and cache sizes. The policy ARC is simple-to-implement and, like LRU, has constant complexity per request. In comparison, policies LRU-2 and LRFU both require logarithmic time complexity in the cache size. The policy ARC is scan-resistant: it allows one-time sequential requests to pass through without polluting the cache. On 23 real-life traces drawn from numerous domains, ARC leads to substantial performance gains over LRU for a wide range of cache sizes. For example, for a SPC1 like synthetic benchmark, at 4GB cache, LRU delivers a hit ratio of 9.19% while ARC achieves a hit ratio of 20.

Journal ArticleDOI
TL;DR: This work introduces and test different Bayesian network classifiers for classifying expressions from video, focusing on changes in distribution assumptions, and feature dependency structures, and proposes a new architecture of hidden Markov models (HMMs) for automatically segmenting and recognizing human facial expression from video sequences.

Patent
Jr. Joseph John Fatula1
15 Dec 2003
TL;DR: In this article, an apparatus, system, and method are disclosed for autonomic management of data operations and performance resources on a grid computing system, including a monitor module, a policy module, and a regulation module.
Abstract: An apparatus, system, and method are disclosed for autonomic management of data operations and performance resources on a grid computing system. An autonomic management apparatus includes a monitor module, a policy module, and a regulation module. The monitor module is configured to monitor the grid computing system for a trigger event. The policy module is configured to access one of a plurality of system policies. Each of the plurality of system policies corresponds to an operational control parameter of a system resource of the grid computing system. The regulation module is configured to autonomically regulate the system resource in response to a recognized trigger event according to one of the plurality of system policies. The trigger event may be a prediction trigger event, an initiation trigger event, a regulation trigger event, or a termination trigger event.

Journal ArticleDOI
02 May 2003-Science
TL;DR: Electrical measurements show that the observed optical emission originates from radiative recombination of electrons and holes that are simultaneously injected into the undoped nanotubes, consistent with a nanotube FET model in which thin Schottky barriers form at the source and drain contacts.
Abstract: Polarized infrared optical emission was observed from a carbon nanotube ambipolar field-effect transistor (FET). An effective forward-biased p-n junction, without chemical dopants, was created in the nanotube by appropriately biasing the nanotube device. Electrical measurements show that the observed optical emission originates from radiative recombination of electrons and holes that are simultaneously injected into the undoped nanotube. These observations are consistent with a nanotube FET model in which thin Schottky barriers form at the source and drain contacts. This arrangement is a novel optical recombination radiation source in which the electrons and holes are injected into a nearly field-free region. Sucha source may form the basis for ultrasmall integrated photonic devices.

Journal ArticleDOI
Alan George Ganek1, T. A. Corbi1
TL;DR: This issue of the IBM Systems Journal explores a broad set of ideas and approaches to autonomic computing--some first steps in what the authors see as a journey to create more self-managing computing systems.
Abstract: This issue of the IBM Systems Journal explores a broad set of ideas and approaches to autonomic computing--some first steps in what we see as a journey to create more self-managing computing systems Autonomic computing represents a collection and integration of technologies that enable the creation of an information technology computing infrastructure for IBM's agenda for the next era of computing--e-business on demand This paper presents an overview of IBM's autonomic computing initiative It examines the genesis of autonomic computing, the industry and marketplace drivers, the fundamental characteristics of autonomic systems, a framework for how systems will evolve to become more self-managing, and the key role for open industry standards needed to support autonomic behavior in heterogeneous system environments Technologies explored in each of the papers presented in this issue are introduced for the reader

Book ChapterDOI
08 Jan 2003
TL;DR: The notion of "certain answers" in indefinite databases for the semantics for query answering in data exchange is adopted and the computational complexity of computing the certain answers in this context is investigated.
Abstract: Data exchange is the problem of taking data structured under a source schema and creating an instance of a target schema that reflects the source data as accurately as possible. In this paper, we address foundational and algorithmic issues related to the semantics of data exchange and to query answering in the context of data exchange. These issues arise because, given a source instance, there may be many target instances that satisfy the constraints of the data exchange problem. We give an algebraic specification that selects, among all solutions to the data exchange problem, a special class of solutions that we call universal. A universal solution has no more and no less data than required for data exchange and it represents the entire space of possible solutions. We then identify fairly general, and practical, conditions that guarantee the existence of a universal solution and yield algorithms to compute a canonical universal solution efficiently. We adopt the notion of "certain answers" in indefinite databases for the semantics for query answering in data exchange. We investigate the computational complexity of computing the certain answers in this context and also study the problem of computing the certain answers of target queries by simply evaluating them on a canonical universal solution.

Proceedings ArticleDOI
09 Jun 2003
TL;DR: This paper presents a new formulation of privacy breaches, together with a methodology, "amplification", for limiting them, and instantiate this methodology for the problem of mining association rules, and modify the algorithm from [9] to limit privacy breaches without knowledge of the data distribution.
Abstract: There has been increasing interest in the problem of building accurate data mining models over aggregate data, while protecting privacy at the level of individual records. One approach for this problem is to randomize the values in individual records, and only disclose the randomized values. The model is then built over the randomized data, after first compensating for the randomization (at the aggregate level). This approach is potentially vulnerable to privacy breaches: based on the distribution of the data, one may be able to learn with high confidence that some of the randomized records satisfy a specified property, even though privacy is preserved on average.In this paper, we present a new formulation of privacy breaches, together with a methodology, "amplification", for limiting them. Unlike earlier approaches, amplification makes it is possible to guarantee limits on privacy breaches without any knowledge of the distribution of the original data. We instantiate this methodology for the problem of mining association rules, and modify the algorithm from [9] to limit privacy breaches without knowledge of the data distribution. Next, we address the problem that the amount of randomization required to avoid privacy breaches (when mining association rules) results in very long transactions. By using pseudorandom generators and carefully choosing seeds such that the desired items from the original transaction are present in the randomized transaction, we can send just the seed instead of the transaction, resulting in a dramatic drop in communication and storage cost. Finally, we define new information measures that take privacy breaches into account when quantifying the amount of privacy preserved by randomization.

Book ChapterDOI
20 Oct 2003
TL;DR: A web of trust is employed, in which each user maintains trusts in a small number of other users, and these trusts are composed into trust values for all other users.
Abstract: Though research on the Semantic Web has progressed at a steady pace, its promise has yet to be realized. One major difficulty is that, by its very nature, the Semantic Web is a large, uncensored system to which anyone may contribute. This raises the question of how much credence to give each source. We cannot expect each user to know the trustworthiness of each source, nor would we want to assign top-down or global credibility values due to the subjective nature of trust. We tackle this problem by employing a web of trust, in which each user maintains trusts in a small number of other users. We then compose these trusts into trust values for all other users. The result of our computation is not an agglomerate "trustworthiness" of each user. Instead, each user receives a personalized set of trusts, which may vary widely from person to person. We define properties for combination functions which merge such trusts, and define a class of functions for which merging may be done locally while maintaining these properties. We give examples of specific functions and apply them to data from Epinions and our BibServ bibliography server. Experiments confirm that the methods are robust to noise, and do not put unreasonable expectations on users. We hope that these methods will help move the Semantic Web closer to fulfilling its promise.

Proceedings ArticleDOI
12 Jan 2003
TL;DR: Besides the applications to the task of identifying good notions of (dis-)similarity between two top k lists, the results imply polynomial-time constant-factor approximation algorithms for the rank aggregation problem with respect to a large class of distance measures.
Abstract: Motivated by several applications, we introduce various distance measures between "top k lists." Some of these distance measures are metrics, while others are not. For each of these latter distance measures: we show that it is "almost" a metric in the following two seemingly unrelated aspects:step-(i) it satisfies a relaxed version of the polygonal (hence, triangle) inequality, andstep-(ii) there is a metric with positive constant multiples that bounds our measure above and below.This is not a coincidence---we show that these two notions of almost being a metric are the same. Based on the second notion, we define two distance measures to be equivalent if they are bounded above and below by constant multiples of each other. We thereby identify a large and robust equivalence class of distance measures.Besides the applications to the task of identifying good notions of (dis-)similarity between two top k lists, our results imply polynomial-time constant-factor approximation algorithms for the rank aggregation problem with respect to a large class of distance measures.

Proceedings Article
21 Aug 2003
TL;DR: A new kernel function between two labeled graphs that is based on an infinite dimensional feature space, so it is fundamentally different from other string or tree kernels based on dynamic programming and presents promising empirical results in classification of chemical compounds.
Abstract: A new kernel function between two labeled graphs is presented. Feature vectors are defined as the counts of label paths produced by random walks on graphs. The kernel computation finally boils down to obtaining the stationary state of a discrete-time linear system, thus is efficiently performed by solving simultaneous linear equations. Our kernel is based on an infinite dimensional feature space, so it is fundamentally different from other string or tree kernels based on dynamic programming. We will present promising empirical results in classification of chemical compounds.

Journal ArticleDOI
TL;DR: The SHOP2 planning system as discussed by the authors received one of the awards for distinguished performance in the 2002 International Planning Competition and described the features that enabled it to excel in the competition, especially those aspects of SHOP 2 that deal with temporal and metric planning domains.
Abstract: The SHOP2 planning system received one of the awards for distinguished performance in the 2002 International Planning Competition. This paper describes the features of SHOP2 which enabled it to excel in the competition, especially those aspects of SHOP2 that deal with temporal and metric planning domains.

Journal ArticleDOI
01 Nov 2003
TL;DR: In this paper, the potential of carbon nanotubes (CNTs) as the basis for a new nanoelectronic technology was evaluated and compared to those of corresponding silicon devices.
Abstract: We evaluate the potential of carbon nanotubes (CNTs) as the basis for a new nanoelectronic technology. After briefly reviewing the electronic structure and transport properties of CNTs, we discuss the fabrication of CNT field-effect transistors (CNTFETs) formed from individual single-walled nanotubes (SWCNTs), SWCNT bundles, or multiwalled (MW) CNTs. The performance characteristics of the CNTFETs are discussed and compared to those of corresponding silicon devices. We show that CNTFETs are very competitive with state-of-the-art conventional devices. We also discuss the switching mechanism of CNTFETs and show that it involves the modulation by the gate field of Schottky barriers at the metal-CNT junctions. This switching mechanism can account for the observed subthreshold and vertical scaling behavior of CNTFETs, as well as their sensitivity to atmospheric oxygen. The potential for integration of CNT devices is demonstrated by fabricating a logic gate along a single nanotube molecule. Finally, we discuss our efforts to grow CNTs locally and selectively, and a method is presented for growing oriented SWCNTs without the involvement of a metal catalyst.

Proceedings ArticleDOI
20 May 2003
TL;DR: An application called 'Semantic Search' is presented which is built on these supporting technologies and is designed to improve traditional web searching and an overview of TAP, the application framework upon which the Semantic Search is built is provided.
Abstract: Activities such as Web Services and the Semantic Web are working to create a web of distributed machine understandable data. In this paper we present an application called 'Semantic Search' which is built on these supporting technologies and is designed to improve traditional web searching. We provide an overview of TAP, the application framework upon which the Semantic Search is built. We describe two implemented Semantic Search systems which, based on the denotation of the search query, augment traditional search results with relevant data aggregated from distributed sources. We also discuss some general issues related to searching and the Semantic Web and outline how an understanding of the semantics of the search terms can be used to provide better results.

Journal ArticleDOI
08 Sep 2003
TL;DR: The main components of audiovisual automatic speech recognition (ASR) are reviewed and novel contributions in two main areas are presented: first, the visual front-end design, based on a cascade of linear image transforms of an appropriate video region of interest, and subsequently, audiovISual speech integration.
Abstract: Visual speech information from the speaker's mouth region has been successfully shown to improve noise robustness of automatic speech recognizers, thus promising to extend their usability in the human computer interface. In this paper, we review the main components of audiovisual automatic speech recognition (ASR) and present novel contributions in two main areas: first, the visual front-end design, based on a cascade of linear image transforms of an appropriate video region of interest, and subsequently, audiovisual speech integration. On the latter topic, we discuss new work on feature and decision fusion combination, the modeling of audiovisual speech asynchrony, and incorporating modality reliability estimates to the bimodal recognition process. We also briefly touch upon the issue of audiovisual adaptation. We apply our algorithms to three multisubject bimodal databases, ranging from small- to large-vocabulary recognition tasks, recorded in both visually controlled and challenging environments. Our experiments demonstrate that the visual modality improves ASR over all conditions and data considered, though less so for visually challenging environments and large vocabulary tasks.

Journal ArticleDOI
TL;DR: The combination of an efficient two-stage coupling scheme and utilization of ultra-long (up to 2mm) photonic crystal waveguides reduces the uncertainty in determining the loss figure to 3dB/cm.
Abstract: We report the design and testing of an SOI-based photonic integrated circuit containing two-dimensional membrane-type photonic crystal waveguides. The circuit comprises spot-size converters to efficiently couple light from a fiber into single-mode strip waveguides and butt-couplers to couple from strip waveguides to photonic crystal waveguides. Each optical interface was optimized to minimize back-reflections and reduce the Fabry-Perot noise. The transmission characteristics of each component are measured and record low propagation losses in photonic crystal waveguides of 24dB/cm are reported. The combination of an efficient two-stage coupling scheme and utilization of ultra-long (up to 2mm) photonic crystal waveguides reduces the uncertainty in determining the loss figure to 3dB/cm.

Posted Content
TL;DR: In this article, the authors proposed a simple and efficient construction of a CCA-secure public-key encryption scheme from any CPA-secure identity-based encryption (IBE) scheme.
Abstract: We propose a simple and efficient construction of a CCA-secure public-key encryption scheme from any CPA-secure identity-based encryption (IBE) scheme. Our construction requires the underlying IBE scheme to satisfy only a relatively “weak” notion of security which is known to be achievable without random oracles; thus, our results provide a new approach for constructing CCA-secure encryption schemes in the standard model. Our approach is quite different from existing ones; in particular, it avoids non-interactive proofs of “well-formedness” which were shown to underlie most previous constructions. Furthermore, applying our conversion to some recently-proposed IBE schemes results in CCA-secure schemes whose efficiency makes them quite practical.