Abstract: A system and method are provided for visually building multi-channel and multi-modal applications. The system includes a process design module for designing application workflow, an integration design module for integrating data sources into the application; a presentation design module for designing application views; a media library; and a componentization module, for packaging designed workflow into reusable components. The system further includes an interactive development/design environment (IDE). The IDE provides a graphical user interface for allowing a developer to visually interact with and operate modules. The system allows a developer to design a single application that can operate across multiple network standards, devices, browsers and languages, and that operate in one or more modes, such as real-time, off-line and asynchronous modes.

Abstract: The requirement for flexible operation is becoming increasingly important in modern industrial systems. This requirement has to be supported at all system levels, including the field level in process industry, as well as the cell and machine control levels in manufacturing industry, where fieldbus-based communication systems are commonly found. Furthermore, typical applications at these levels require both time- and event-triggered communication services, in most cases under stringent timing constraints, to convey state data in the former case and alarms and management data in the latter. However, neither the requirement for flexible operation under guaranteed timeliness nor for joint support of time and event-triggered traffic are efficiently fulfilled by most of existing fieldbus systems. This paper presents a new protocol, flexible time-triggered communication on controller area network, which fulfills both requirements: it supports time-triggered communication in a flexible way as well as being an efficient combination of both time- and event-triggered traffic with temporal isolation. These types of traffic are handled by two complementary subsystems, the synchronous and the asynchronous messaging systems, respectively. The paper includes a justification for the new protocol as well as its description and worst case temporal analysis for both subsystems. This analysis shows the capability of the protocol to convey real-time traffic of either type.

Abstract: The invention provides a session-based bi-directional multi-tier client-server asynchronous information database search and retrieval system for sending a character-by-character string of data to an intelligent server that can be configured to immediately analyze the lengthening string character-by-character and return to the client increasingly appropriate database information as the client sends the string.

Abstract: A decentralized asynchronous wireless communication system is disclosed for providing voice and data communication that allows flexibility of communication paths for local communication or for communication to external networks. The system makes use of communication docking bays that may communicate in a local mode with other communication docking bays or handsets within a same microcell via signal extenders. In an extended mode, a communication docking bay located in a first microcell of a first macrocell may communicate with a second communication docking bay or handset in a second microcell of the first macrocell via signal extenders and a network extender. In a remote mode, a communication docking bay located in a first microcell of a first macrocell may communicate with a second communication docking bay or handset in a second microcell of a second macrocell via signal extenders and network extenders. The communication docking bays also provide a communication path to a Public Switch Telephone Network and other communication medium. This feature provides an alternate means of connecting a mobile handset to a Public Switch Telephone Network without communicating through a network extender. The system is particularly suitable for operation in rural areas having a low population density.

Abstract: The aim of this study is to examine the quality of asynchronous interaction in web-based conferencing among pre-service teachers. Because all successful communication presumes perspective-taking skills and reciprocal understanding among the participants, we study whether the students are able to reach in reciprocal interaction and thus create educationally relevant high-level web-based discussion. The research project has its foundation in socio-constructivist learning theories, one of the most important principles of which is the idea of apprenticeship in thinking. To create a learning project in web-based conferencing we developed pedagogical practices, which enhance higher-level networked communication and make use of theoretical and expert knowledge. The study combines the power of asynchronous conferencing with peer and mentor collaboration to electronically apprentice student learning. The subjects of the study are pre-service teachers in the United States (N ?=?40) and Finland (N ?=?30) who use an ...

Abstract: Verifiable secret sharing is an important primitive in distributed cryptography. With the growing interest in the deployment of threshold cryptosystems in practice, the traditional assumption of a synchronous network has to be reconsidered and generalized to an asynchronous model. This paper proposes the first practical verifiable secret sharing protocol for asynchronous networks. The protocol creates a discrete logarithm-based sharing and uses only a quadratic number of messages in the number of participating servers. It yields the first asynchronous Byzantine agreement protocol in the standard model whose efficiency makes it suitable for use in practice. Proactive cryptosystems are another important application of verifiable secret sharing. The second part of this paper introduces proactive cryptosystems in asynchronous networks and presents an efficient protocol for refreshing the shares of a secret key for discrete logarithm-based sharings.

Abstract: This book is devoted to logic synthesis and design techniques for asynchronous circuits. It uses the mathematical theory of Petri Nets and asynchronous automata to develop practical algorithms implemented in a public domain CAD tool. Asynchronous circuits have so far been designed mostly by hand, and are thus much less common than their synchronous counterparts, which have enjoyed a high level of design automation since the mid-1970s. Asynchronous circuits, on the other hand, can be very useful to tackle clock distribution, modularity, power dissipation and electro-magnetic interference in digital integrated circuits. This book provides the foundation needed for CAD-assisted design of such circuits, and can also be used as the basis for a graduate course on logic design.

Abstract: We develop synchronization algorithms for both the downlink and the uplink of quasi-synchronous and asynchronous orthogonal frequency division multiple access systems. Unlike existing alternatives, the proposed time- and carrier-offset estimators do not require the transmission of known sequences and exhibit performance independent of the underlying channel zero locations. The only necessary assumption is that there are virtual subcarriers which are not occupied by any user. We derive a closed-form variance expression for the carrier-offset estimator at high signal-to-noise ratio (SNR), as a function of the number of active users and the SNR. We compare our method with alternative ones and validate our theoretical derivations with simulation results.

Abstract: A network based educational system is described. The system generally includes a student interface, a classroom interface and an administrative interface. Synchronous and asynchronous applications are used, typically with streaming video to deliver courseware to learners on the system.

Abstract: From the Publisher: Network synchronization deals with the distribution of time and frequency across a network of clocks often spread over a wide geographical area. The goal is to align (i.e. synchronize) the time and frequency scales of all clocks, by using the communication capacity of their interconnecting links. Network synchronization plays a central role in digital telecommunications as it determines the quality of most services offered by the network operator. However, the importance of network synchronization is often underestimated and how to solve quality-of-service degradation caused by synchronization difficulties can become problematical to all but a synchronization engineer. Systematically covers a wide spectrum of both theoretical and practical topics Features a clear and profound description of synchronous and asynchronous digital multiplexing (PDH, SDH), jitter and timing aspects of SDH networks Expounds synchronization network principles and implementation issues, clock modelling, time and frequency measurement Presents recent advances in telecommunications clock characterization and measurement If you are a system engineer, researcher, designer or postgraduate student searching for both the basics and an insight into more advanced areas currently under discussion then you will find Synchronization of Digital Telecommunications Networks an enlightening read. It will also prove to be a valuable sourcebook for senior undergraduates and technical personnel in telecommunications companies.

Abstract: This document describes the Asynchronous Layered Coding (ALC) protocol, a massively scalable reliable content delivery protocol. Asynchronous Layered Coding combines the Layered Coding Transport (LCT) building block, a multiple rate congestion control building block and the Forward Error Correction (FEC) building block to provide congestion controlled reliable asynchronous delivery of content to an unlimited number of concurrent receivers from a single sender.

Abstract: This paper describes a Secure INtrusion-Tolerant Replication Architecture (SINTRA) for coordination in asynchronous networks subject to Byzantine faults. SINTRA supplies a number of group communication primitives, such as binary and multi-valued Byzantine agreement, reliable and consistent broadcast, and an atomic broadcast channel. Atomic broadcast immediately provides secure state-machine replication. The protocols are designed for an asynchronous wide-area network, such as the Internet, where messages may be delayed indefinitely, the servers do not have access to a common clock, and up to one third of the servers may fail in potentially malicious ways. Security is achieved through the use of threshold public-key cryptography, in particular through a cryptographic common coin based on the Diffie-Hellman problem that underlies the randomized protocols in SINTRA. The implementation of SINTRA in Java is described and timing measurements are given for a test-bed of servers distributed over three continents. They show that extensive use of public-key cryptography does not impose a large overhead for secure coordination in wide-area networks.

Abstract: An enquiry proxy and session manager (60) is arranged to provide the output (45) of a natural language enquiry converter to a voice based enquiry system (62) and to output results provided from said voice based system using a response generator (68) in a natural language manner.

Abstract: The dominant hardware design paradigm is a synchronous (clocked) design style. Recent research has made asynchronous or self-timed systems attractive again. This paper introduces Balsa, a language and framework for synthesizing circuits using a technique of syntax direct translation. Balsa has been used to generate the DMA controller used in AMULET3i, an integrated asynchronous microprocessor design for embedded systems. This paper introduces the key features of the language.

Abstract: A new architecture and operational techniques for supporting high quality live and on-demand streaming multimedia on a data network. By using Helper machines inside the network as data forwarding, caching, and buffering agents, and by forming meshes among Helper machines, advantages of homogeneous, synchronous multicast transmission and of heterogeneous, asynchronous reception are achieved. The architecture provides essentially transparently support to the receivers for near-zero start-up latency, improved playback quality, improved CR-like operations. These are achieved while reducing network and server load compared to today's multimedia networking techniques.

Abstract: This paper studies the diagnosis of asynchronous discrete event systems. We follow a so-called true concurrency approach, in which neither the global state nor global time are available. Instead, we use only local states in combination with a partial order model of time; our basic mathematical tool is that of Petri net unfoldings. This study was motivated by the problem of event correlation in telecommunications network management.

Abstract: Interaction plays an important role in the success of distance learning As most distance learning environments mainly utilize asynchronous computer-mediated communication (CMC) systems, interaction research that focuses on synchronous CMC is largely ignored This study scrutinized the patterns of learner-learner interaction in a distance learning environment Student interactions in synchronous and asynchronous CMC systems were compared The results of the research suggest that constructivist-based instructional activities, such as student-moderated discussion and small-group cooperative learning, are conducive to interaction Overall, a higher percentage of social-emotional interactions occurred in the synchronous mode than in the asynchronous mode Students spent more time in task-oriented interaction in asynchronous discussions than they did in the synchronous mode In moderating online seminars, student moderators who followed the guidelines of student-centered discussions (SCD) were able to encourage full participation in an online seminar Recommendations for the design of instructional activities and interactive interfaces were also made in order to improve distance learning environments

Abstract: Verifiable secret sharing is an important primitive in distributed cryptography. With the growing interest in the deployment of threshold cryptosystems in practice, the traditional assumption of a synchronous network has to be reconsidered and generalized to an asynchronous model. This paper proposes the first practical verifiable secret sharing protocol for asynchronous networks. The protocol creates a discrete logarithm-based sharing and uses only a quadratic number of messages in the number of participating servers. It yields the first asynchronous Byzantine agreement protocol in the standard model whose efficiency makes it suitable for use in practice. Proactive cryptosystems are another important application of verifiable secret sharing. The second part of this paper introduces proactive cryptosystems in asynchronous networks and presents an efficient protocol for refreshing the shares of a secret key for discrete logarithm-based sharings.

Abstract: A device and method for configuring an UL-DPCCH. One or more UL-DPCCHs, especially a UL-DPCCH for supporting HSDPA, are constructed in code division multiplexing and transmitted according to the characteristics of control information. The UL-DPCCH of the present invention that delivers various kinds of control information can be configured flexibly and operate in compatibility with a conventional asynchronous mobile communication system.

Abstract: System and method for asynchronous distributed optimization of an enterprise. The system includes a based optimization system (402) operates in conjunction with an enterprise or process (404) to optimize the process (404) to optimize the process. The computer system (402) executes software programs which receive process data from the process (404).

Abstract: A communication system including a transmitter, a receiver, and a serial link, in which encoded data (e.g., video, audio, and optionally also other auxiliary data) are transmitted from the transmitter to the receiver. The serial link can but need not be a TMDS or TMDS-like link. In typical embodiments, packets of encoded audio data are transmitted over each of one or more channels of the link during data islands between bursts of encoded video data, a pixel clock is transmitted over the link, and the receiver regenerates a clock for the audio data using time code data in the packets and the pixel clock. Other aspects of the invention are transmitters for transmitting encoded data and a pixel clock over a serial link, receivers for receiving such data and pixel clock and performing audio clock regeneration, and methods for transmitting encoded data and a pixel clock over a serial link and performing clock regeneration using the transmitted data and pixel clock.

Abstract: This study was conducted to extend our understanding of the impacts on instruction when asynchronous text-based Internet communication technology is integrated into distance courses. The researchers interviewed twelve university instructors to examine Berge's (1995) four roles of the use of technologies as an interview guide. Moore's (1972) theory of transactional distance was used to interpret the data. The results revealed that as university instructors in distance education programs gain experience, they find it is possible to translate many face-to-face instructional strategies to the online classroom and learn the technical aspects necessary for effective use of asynchronous text-based Internet communication tools. However, most instructors continue to experience a tension between structure, dialogue, and autonomy.

Abstract: Systems and methods for interfacing asynchronous and non-asynchronous data media, such as for interfacing an asynchronous computing I/O bus medium with a non-asynchronous T/N medium. The disclosed systems and methods may be implemented, for example, in a manner that allows conversion or transformation of information in asynchronous-compliant form to information in non-asynchronous-compliant form in real time.

Abstract: Locality principles are becoming paramount in controlling advancement of data through pipelined systems. Achieving fine grained power down and progressive pipeline stalls at the local stage level is therefore becoming increasingly, important to enable lower dynamic power consumption while keeping introduced switching noise under control as well as avoiding global distribution of timing critical stall signals. It has long been known that the interlocking properties of as asynchronous pipelined systems have a potential to provide such benefits. However it has not been understood how such interlocking can be achieved in synchronous pipelines. This paper presents a novel technique based on local clock gating and synchronous handshake protocols that achieves stage level interlocking characteristics in synchronous pipelines similar to that of asynchronous pipelines. The presented technique is directly applicable to traditional synchronous pipelines and works equally well for two-phase clocked pipelines based on transparent latches, as well as one-phase clocked pipelines based on master-slave latches.

Abstract: The provision of a reliable communication infrastructure for mobile agents is still an open research issue. The challenge to reliability we address in this work does not come from the possibility of faults, but rather from the mere presence of mobility, which complicates the problem of ensuring the delivery of information even in a fault-free network. For instance, the asynchronous nature of message passing and agent migration may cause situations where messages forever chase a mobile agent that moves frequently from one host to another. Current solutions rely on conventional technologies that either do not provide a solution for the aforementioned problem, because they were not designed with mobility in mind, or enforce continuous connectivity with the message source, which in many cases defeats the very purpose of using mobile agents. In this paper, we propose an algorithm that guarantees delivery to highly mobile agents using a technique similar to a distributed snapshot. A number of enhancements to this basic idea are discussed, which limit the scope of message delivery by allowing dynamic creation of the connectivity graph. Notably, the very structure of our algorithm makes it amenable not only to guarantee message delivery to a specific mobile agent, but also to provide multicast communication to a group of agents, which constitutes another open problem in research on mobile agents. After presenting our algorithm and its properties, we discuss its implementability by analyzing the requirements on the underlying mobile agent platform, and argue about its applicability.

Abstract: We study the performance of a class of time-offset estimation algorithms for synchronization of master-slave nodes based on asynchronous transfer of timing cells when GPS is not used. We implement a synchronization control mechanism based on cell acknowledgment time-out (TO) with wait or no wait options. We analyze the mechanism reliability and performance parameters over symmetric links using an exponential cell delay variation model. We show that the maximum-likelihood offset estimator does not exist for the exponential likelihood function. We analytically provide RMS error result comparisons for five ad hoc offset estimation algorithms: the median round delay, the minimum round delay, the minimum link delay (MnLD), the median phase, and the average phase. We show that the MnLD algorithm achieves the best accuracy over symmetric links without having to impose a strict TO control, which substantially speeds up the algorithm. We also discuss an open-loop estimation updating mechanism based on standard clock models.

Abstract: In this dissertation, we consider a distributed implementation of the π-calculus, more precisely, the version of the π-calculus with mixed choice. To this end, we present the probabilistic asynchronous π-calculus, which is an extension of the asynchronous π-calculus enhanced with a notion of random choice. We define an operational semantics which distinguishes between probabilistic choice, made internally by the process, and nondeterministic choice, made externally by an adversary scheduler. This distinction will allow us to reason about the probabilistic correctness of algorithms under certain schedulers. We show that in this language we can solve the electoral problem, which was proved not possible in the asynchronous π-calculus. We propose a randomized distributed encoding of the π-calculus, using the probabilistic asynchronous π-calculus, and we show that our solution is correct with probability 1 under any proper adversary with respect to a notion of testing semantics. Finally, in order to prove that the probabilistic asynchronous π-calculus is a sensible paradigm for the specification of distributed algorithms, we define a distributed implementation of the synchronization-closed probabilistic asynchronous π-calculus in the Java language.

Abstract: The invention provides an ARQ scheme where data packets are transmitted from the transmitter to the receiver in first predetermined time intervals, and positive (ACK) and negative (NAK) acknowledgement messages are transmitted from the receiver to the transmitter in second predetermined time intervals. For each data packet that has been transmitted from the transmitter to the receiver, at least two second time intervals can be used for transmitting the acknowledgement message. The invention therefore improves over synchronous feedback transmission schemes by adding flexibility without incorporating the drawback of asynchronous transmission schemes that are known to have a high signalling overhead. The invention is preferably applicable to UMTS and HSDPA systems but can also be applied in any other communications system. The feedback channel may be uplink or downlink.

Abstract: A class of asynchronous dynamical systems with rate constraints that is a modification of the class defined by Hassibi et al. (1999) is introduced. A numerical procedure for a quadratic stability analysis, based on a combination of LMI and a genetic algorithm is proposed. Applications to networked control systems with packet dropout and to convergence of asynchronous fixed point iterations are described. The results obtained are put in perspective as well as compared with those obtained earlier in the literature.