Showing papers on "Systems architecture published in 2001"

SEDA: an architecture for well-conditioned, scalable internet services

Abstract: We propose a new design for highly concurrent Internet services, which we call the staged event-driven architecture (SEDA). SEDA is intended to support massive concurrency demands and simplify the construction of well-conditioned services. In SEDA, applications consist of a network of event-driven stages connected by explicit queues. This architecture allows services to be well-conditioned to load, preventing resources from being overcommitted when demand exceeds service capacity. SEDA makes use of a set of dynamic resource controllers to keep stages within their operating regime despite large fluctuations in load. We describe several control mechanisms for automatic tuning and load conditioning, including thread pool sizing, event batching, and adaptive load shedding. We present the SEDA design and an implementation of an Internet services platform based on this architecture. We evaluate the use of SEDA through two applications: a high-performance HTTP server and a packet router for the Gnutella peer-to-peer file sharing network. These results show that SEDA applications exhibit higher performance than traditional service designs, and are robust to huge variations in load.

A real-time traffic signal control system: architecture, algorithms, and analysis

Abstract: The paper discusses a real-time traffic-adaptive signal control system referred to as RHODES. The system takes as input detector data for real-time measurement of traffic flow, and “optimally” controls the flow through the network. The system utilizes a control architecture that (1) decomposes the traffic control problem into several subproblems that are interconnected in an hierarchical fashion, (2) predicts traffic flows at appropriate resolution levels (individual vehicles and platoons) to enable pro-active control, (3) allows various optimization modules for solving the hierarchical subproblems, and (4) utilizes a data structure and computer/communication approaches that allow for fast solution of the subproblems, so that each decision can be downloaded in the field appropriately within the given rolling time horizon of the corresponding subproblem. The RHODES architecture, algorithms, and its analysis are presented. Laboratory test results, based on implementation of RHODES on simulation models of actual scenarios, illustrate the effectiveness of the system.

Habitat monitoring: Application driver for wireless communications technology

Abstract: As new fabrication and integration technologies reduce the cost and size of micro-sensors and wireless interfaces, it becomes feasible to deploy densely distributed wireless networks of sensors and actuators. These systems promise to revolutionize biological, earth, and environmental monitoring applications, providing data at granularities unrealizable by other means. In addition to the challenges of miniaturization, new system architectures and new network algorithms must be developed to transform the vast quantity of raw sensor data into a manageable stream of high-level data. To address this, we propose a tiered system architecture in which data collected at numerous, inexpensive sensor nodes is filtered by local processing on its way through to larger, more capable and more expensive nodes.We briefly describe Habitat monitoring as our motivating application and introduce initial system building blocks designed to support this application. The remainder of the paper presents details of our experimental platform.

How to build smart appliances

Abstract: In this article smart appliances are characterized as devices that are attentive to their environment. We introduce a terminology for situation, sensor data, context, and context-aware applications because it is important to gain a thorough understanding of these concepts to successfully build such artifacts. In the article the relation between a real-world situation and the data read by sensors is discussed; furthermore, an analysis of available sensing technology is given. Then we introduce an architecture that supports the transformation from sensor data to cues then to contexts as a foundation to make context-aware applications. The article suggests a method to build context-aware devices; the method starts from situation analysis, offers a structured way for selection of sensors, and finally suggests steps to determine recognition and abstraction methods. In the final part of the article the question of how this influences the applications is raised and the areas of user interfaces, communication, and proactive application scheduling are identified. We conclude with the description of a case study where a mobile phone was made aware of its environment using different sensors. The profile settings of the phone (ringing mode etc.) are automatically selected according to the real world situation the phone is used in.

Ad hoc peer-to-peer mobile radio access system interfaced to the pstn and cellular networks

Abstract: An ad-hoc, peer-to-peer radio access system for cellular communications systems using time division duplex as a way of maximizing the bits/hz/km2 for cellular systems. The network architecture of the ad-hoc system allows the radio access to be integrated with the fixed components of a conventional cellular system, PSTN or ISP. The objective is to make the system of the invention transparent to the features and services provided by the external network. The advantages of such a system to a cellular operator are that significantly less infrastructure is required, and that the RF spectrum is more efficiently utilized resulting in much lower building and operating costs. The system architecture is comprised of remote terminals, routers, gateways, and at least one gateway controller that interfaces the ad-hoc system to a cellular network system. The ad-hoc system of the invention allows for both voice and data transmissions and receptions.

The coming-of-age of software architecture research

Abstract: Over the past decade, software architecture research has emerged as the principled study of the overall structure of software systems, especially the relations among subsystems and components. From its roots in qualitative descriptions of useful system organizations, software architecture has matured to encompass broad explorations of notations, tools, and analysis techniques. Whereas initially the research area interpreted software practice, it now offers concrete guidance for complex software design and development. We can understand the evolution and prospects of software architecture research by examining the research paradigms used to establish its results. These are, for the most part, the paradigms of software engineering. We advance our fundamental understanding by posing research questions of several kinds and applying appropriate research techniques, which differ from one type of problem to another, yield correspondingly different kinds of results, and require different methods of validation. Unfortunately, these paradigms are not recognized explicitly and are often not carried out correctly; indeed not all are consistently accepted as valid. This retrospective on a decade-plus of software architecture research examines the maturation of the software architecture research area by tracing the types of research questions and techniques used at various stages. We will see how early qualitative results set the stage for later precision, formality, and automation and how results build up over time. This generates advice to the field and projections about future impact.

Toward an integrated model of driver behavior in cognitive architecture

Abstract: Driving is a multitasking activity that requires drivers to manage their attention among various driving- and non-driving-related tasks. When one models drivers as continuous controllers, the discrete nature of drivers' control actions is lost and with it an important component for characterizing behavioral variability. A proposal is made for the use of cognitive architectures for developing models of driver behavior that integrate cognitive and perceptual-motor processes in a serial model of task and attention management. A cognitive architecture is a computational framework that incorporates built-in, well-tested parameters and constraints on cognitive and perceptual-motor processes. All driver models implemented in a cognitive architecture necessarily inherit these parameters and constraints, resulting in more predictive and psychologically plausible models than those that do not characterize driving as a multitasking activity. These benefits are demonstrated with a driver model developed in the ACT-R cognitive architecture. The model is validated by comparing its behavior to that of human drivers navigating a four-lane highway with traffic in a fixed-based driving simulator. Results show that the model successfully predicts aspects of both lower-level control, such as steering and eye movements during lane changes, and higher-level cognitive tasks, such as task management and decision making. Many of these predictions are not explicitly built into the model but come from the cognitive architecture as a result of the model's implementation in the ACT-R architecture.

Formal foundation and conceptual design of dynamic adaptations in a workflow management system

Abstract: While the different aspects of flexible workflow management are still under discussion, the ability to adapt the structure of running workflow instances to modified workflow schemas is an important property of a flexible workflow management system. In this paper, we present the formal foundation and conceptual design of dynamic adaptations in an object-oriented workflow management system. We describe in some detail how workflow schemas are represented. The system architecture, based on the CORBA object-oriented middleware, is overviewed, and the implementation of dynamic adaptations is sketched. An example introduces the graphical user interface of the system and shows a dynamic adaptation.

The K-Component Architecture Meta-model for Self-Adaptive Software

Abstract: Software architectures have recently emerged as a level of design concerned with specifying the overall structure of a system. Traditionally, software architectures only provide static descriptions of the participants and interaction structures in a system. Dynamic software architectures, however, can be reconfigured at runtime and therefore provide support for building dynamically adaptable applications. Software architectures can be specified using architectural reflection. In this paper we introduce an architecture meta-model that realises a dynamic software architecture. The architecture meta-model reifies the configuration graph of the architecture and is automatically generated from our component definitions and implementation language source-code. We show how graph transformations that re-write the architecture's configuration graph can be implemented as reflective programs, called adaptation contracts. Adaptation contracts are written in a separate programming language, thus cleanly separating the adaptation code from the computational code. Adaptation contracts can even be replaced at run-time. They are deployed in a run-time meta-level architecture that addresses issues of system safety, integrity and overhead during graph transformation. The paper also describes a prototype implementation of our model called K-Components.

System and method for monitizing network connected user bases utilizing distributed processing systems

Abstract: A distributed computing system architecture and an associated method are disclosed for allowing the monitization of third-party network user bases. The distributed computing system includes a plurality of network connected distributed devices providing computing resources that can be utilized to process customer project tasks. Third-party network service providers can monitize their respective user bases by providing user identification information to the distributed processing system and by facilitating the inclusion of the computing resources related to their user bases within the distributed processing system. In this way, revenue generated from customer payments for project processing can be shared with the third party in relation to the resources made available to the distributed computing system. For example, an Internet-based free or low cost service provider, such as a provider offering free Internet access, e-mail, file sharing services or any other Internet-based service, can monitize its user base by offering services to its users at least in part in return for an agreement by the users to allow computing resources related to the users to be utilized by the distributed processing system.

Intelligent software agent system architecture

Abstract: A software architecture supports deployment of mobile software agents over the Internet. Mobile software agents or “bots” are bifurcated into two parts, a first part executable on a user's client platform (“mBot”), and a corresponding second part, called “sBot,” executable on a remote “bot server”. botServer implements virtual “meeting places” for visiting bots, and provides event notification, plug-ins and other services. The new system further includes a component called “botBox” executable on another server (which may be the same as the bot server), that tracks the status and locations of running bots, handles communications, and enables continuing operation while the user is off-line. Knowledge about the user, including private information, is finely controlled by custom user profiles which are defined by the user, but made available to the remote-executing sBot only through the botBox intermediary.

Evaluation of the traffic-performance characteristics of system-on-chip communication architectures

Abstract: The emergence of several communication architectures for system-on-chips provides designers with a variety of design alternatives. In addition, the need to customize the system architecture for a specific application or domain, makes it critical for a designer to be aware of (and to evaluate) the trade-offs involved in selecting an optimal system-level communication architecture. While it is generally known that different communication architectures may be better suited to serve the needs of different applications, very little work has been done on quantitatively comparing and characterizing their performance for different classes of on-chip communication traffic. In this paper, we present a detailed analysis of the performance of various system-on-chip communication architectures under different classes of on-chip communication traffic. We present high-level models of a few commonly used on-chip architectures, which take into account key architectural features, including their characteristic topologies and communication protocols. We present an efficient methodology to study the performance of each architecture, making use of (i) parameterized traffic generators, that help create a wide variety of on-chip communication traffic, and (ii) an implementation independent communication interface abstraction, to enable plug-and-play evaluation of alternative communication architectures. Our experiments show that the effectiveness of each architecture varies significantly, depending on the characteristics of the communication traffic (average communication rates of common architectures were seen to vary by as much as 409%). Additionally, they also demonstrate the criticality of judiciously selecting an on-chip communication architecture for a given application. We discuss the implications of our experiments, including the relative strengths and weaknesses of the considered architectures, the classes of traffic that each is well suited to, and requirements for system design tools and methodologies in order to support efficient communication architecture selection and customization.

Design and Deployment of a Passive Monitoring Infrastructure

Abstract: This paper presents the architecture of a passive monitoring system installed within the Sprint IP backbone network. This system differs from other packet monitoring systems in that it collects packet-level traces from multiple links within the network and provides the capability to correlate the data using highly accurate GPS timestamps. After a thorough description of the monitoring systems, we demonstrate the system's capabilities and the diversity of the results that can be obtained from the collected data. These results include workload characterization, packet size analysis, and packet delay incurred through a single backbone router. We conclude with lessons learned from the development of the monitoring infrastructure and present future research goals.

Software architecture: introducing IEEE Standard 1471

Abstract: IEEE Standard 1471 identifies sound practices to establish a framework and vocabulary for software architecture concepts.In 2000, the Computer Society approved IEEE Standard 1471, which documents a consensus on good architectural description practices. Five core concepts and relationships provide the foundation for the approved IEEE 1471 version: every system has an architecture, but an architecture is not a system; an architecture and an architecture description are not the same thing; architecture standards, descriptions, and development processes can differ and be developed separately; architecture descriptions are inherently multiviewed; and separating the concept of an object's view from its specification is an effective way to write architecture description standards. IEEE 1471 focuses on both software intensive systems and more general systems, such as information systems, embedded systems, systems-of-systems, product lines, and product families in which software plays a substantial role in development, operation, or evolution.

A multi-system architecture using general purpose active-backplane and expansion-bus compatible single board computers and their peripherals for secure exchange of information and advanced computing

Abstract: A general purpose modified single board computer (MSBC) device (162) for operational and performance enhancement of computer systems. The modification configures the bus interface of the MSBC (162) such that it can reside on the expansion-bus (104) of a host computer system and operate as an add-in card to the hosting system. This device provides means to employ the resources of a full computer system, to enhance the operation and performance of an information system hosting this device. The MSBC (162) permits a 'system in system' architecture thus efficiently enabling advanced capabilities for existing and future computer and information systems.

Using Gauges for Architecture-Based Monitoring and Adaptation

Abstract: An increasingly important requirement for complex systems is the capability to adapt at runtime in order to accommodate variable resources, system errors, and changing requirements. An essential aspect of adaptation is the ability to observe a system’s runtime behavior and interpret those observations in terms that permit a high-level understanding of the system’s status. In this paper we describe mechanisms for monitoring a running system, interpreting monitored data in terms of the system’s architecture, and analyzing the system architecture to ascertain if the system’s runtime behavior fits within the envelope of acceptable behavior. We illustrate the use of these mechanisms for the important special case of system performance monitoring.

System architecture for remote access and control of environmental management

Abstract: A fault tolerant system by which individual components of a server are monitored and controlled through independent, programmable microcontrollers interconnected through a microcontroller network. An external agent can control and monitor the microcontrollers by extending the interconnection network beyond the physical server. The extension to the interconnection network converts protocols between media, and directs the microcontrollers and the state managed by the microcontrollers. Intervention of the server operating system software is not required and is not utilized for the access and control operations. A remote interface board provides the interface between the microcontroller network and an external modem that communicates with a remote client computer. The remote interface board also provides for connection to a local client computer.

An Architecture for the Effective Support of Adaptive Context-Aware Applications

Abstract: Mobile applications are required to operate in environments characterised by change More specifically, the availability of resources and services may change significantly during a typical period of system operation As a consequence, adaptive mobile applications need to be capable of adapting to these changes to ensure they offer the best possible level of service to the user Our experiences of developing and evaluating adaptive context-aware applications in mobile environments has led us to believe that existing architectures fail to provide the necessary support for such applications In this paper, we discuss the shortcomings of existing approaches and present work on our own architecture that has been designed to meet the key requirements of context-aware adaptive applications

Reconsidering Internet mobility

Abstract: Despite the popularity of mobile computing platforms, appropriate system support for mobile operation is lacking in the Internet. The paper argues that this is not for lack of deployment incentives, but because a comprehensive system architecture that efficiently addresses the needs of mobile applications does not exist. We identify five fundamental issues raised by mobility: location, preservation of communication, disconnection handling, hibernation, and reconnection, and suggest design guidelines for a system that attempts to support Internet mobility. In particular, we argue that a good system architecture should: (i) eliminate the dependence of higher protocol layers upon lower-layer identifiers; (ii) work with any application-selected naming scheme; (iii) handle (unexpected) network disconnections in a graceful way, exposing its occurrence to applications; and (iv) provide mobility services at the mobile nodes themselves, rather than via proxies. Motivated by these principles, we propose a session-oriented, end-to-end architecture called Migrate, and briefly examine the set of services it should provide.

Dedicated echo canceler for a workstation

Abstract: A multimedia collaboration system that integrates separate real-time and asynchronous networks—the former for real-time audio and video, and the latter for control signals and textual, graphical and other data—in a manner that is interoperable across different computer and network operating system platforms and which closely approximates the experience of face-to-face collaboration, while liberating the participants from the limitations of time and distance. These capabilities are achieved by exploiting a variety of hardware, software and networking technologies in a manner that preserves the quality and integrity of audio/video/data and other multimedia information, even after wide area transmission, and at a significantly reduced networking cost as compared to what would be required by presently known approaches. The system architecture is readily scalable to the largest enterprise network environments. It accommodates differing levels of collaborative capabilities available to individual users and permits high-quality audio and video capabilities to be readily superimposed onto existing personal computers and workstations and their interconnecting LANs and WANs. In a particular preferred embodiment, a plurality of geographically dispersed multimedia LANs are interconnected by a WAN. The demands made on the WAN are significantly reduced by employing multi-hopping techniques, including dynamically avoiding the unnecessary decompression of data at intermediate hops, and exploiting video mosaicing, cut-and-paste and audio mixing technologies so that significantly fewer wide area transmission paths are required while maintaining the high quality of the transmitted audio/video.

A Model-Based, Open Architecture for Mobile, Spatially Aware Applications

Abstract: With the emerging availability of small and portable devices that are able to determine their position and to communicate wirelessly, mobile and spatially aware applications become feasible. These applications rely on information that is bound to locations. In this paper we present NEXUS, a platform for such applications, which is open for both new applications and new information providers, similar to the World Wide Web. Distributed servers provide location-based information, which is federated to an integrated view for the applications. To achieve this goal, we present the concept of the Augmented World Model, which is a common data model for location-based information. We give an example to show how applications can use this platform.

Architecture-Level Dependence Analysis for Software Systems

Abstract: The emergence of formal software architecture description languages provides an opportunity to perform analyses at high levels of abstraction, as well as early in the development process. Previous research has primarily focused on developing techniques such as algebraic and transition-system analysis to detect component mismatches or global behavioral incorrectness. In this paper we motivate the utility and describe the challenges in developing a different kind of analysis for use at the architectural level, namely dependence analysis. Various kinds of dependence analyses have been used widely at the implementation level to aid program optimization, anomaly checking, program understanding, testing, and debugging. However, the languages used for architectural description offer quite different features than the languages for which traditional dependence analysis techniques have been developed. We describe our initial approach to architecture-level dependence analysis and illustrate that approach through a prototype tool we have built, called Aladdin, to automatically perform the analysis.

Auto) mobile communication in a heterogeneous and converged world

Abstract: We discuss services and system architecture issues for future wireless communication in the vehicular environment We consider the problem of wireless network heterogeneity that will be a consequence of emerging technologies such as wireless LANs, ad hoc networks, and broadcast systems, in addition to third-generation cellular standards like UMTS In particular, a communication gateway architecture is proposed as an essential building block in future automobile systems It enables services and applications within the car to transparently use different wireless communication systems Our article gives a high-level view of the component architecture of the gateway and its adaptation layer to the wireless infrastructure

Distributed architectures and logical-task decomposition in multimedia surveillance systems

Abstract: In the past few years, the development of complex surveillance systems has captured the interest of both the research and industrial worlds. Strong and challenging requirements of modern society are involved in this problem, which aims to increase safety and security in several application domains such as transport, tourism, home and bank security, military applications, etc. At the same time, fast improvements in microelectronics, telecommunications, and computer science make it necessary to consider new perspectives in this field. The main objective of this paper is to investigate, discuss, and evaluate the impact of distributed processing and new communication techniques on multimedia surveillance systems, which represent the so-called third-generation surveillance systems (3 GSSs). In particular, aspects related to the distribution of intelligence among multiple-processing and wide-bandwidth resources are discussed in detail. It is shown how distribution of intelligence can be obtained by a hierarchical architecture that partitions, in a dynamic way, the main logical processing tasks (i.e., representation, recognition, and communication) performed in a 3 GSS physical architecture made up of intelligent cameras, hubs, and central control rooms. The advantages of this solution are pointed out in terms of 1) increased flexibility and reconfigurability and 2) optimal allocation of available processing and bandwidth resources. Finally, a case study is analyzed that allows one to gain a deeper insight into a distributed surveillance system.

The Role of a Self-Reference System in Spatial Navigation

Abstract: The self-reference system architecture developed to explain the retrieval of spatial knowledge from long-term memory is reviewed and expanded to include navigational tracking as one of its operations. A distinction is made between the operation of the self-reference system at a perceptual-motor and a representational level, and a case is made that if a representational self-reference system is to function as a navigational tracking device, it must be closely connected with the perceptual-motor level. Existing empirical evidence is reviewed and new empirical evidence is reported that explores the connections between the two levels of functioning. Additionally, the operations that would enable a self-reference system to function as a tracking device are derived from an animal model of sense of direction. The ideas explored in this manuscript rely on the premise that spatial memory systems evolved in the service of spatial navigation.

Universal Serial Bus system architecture

Abstract: From the Book: PREFACE: The MindShare Architecture Series The MindShare Architecture book series includes: ISA System Architecture, EISA System Architecture, 80486 System Architecture, PCI System Architecture, Pentium System Architecture, PCMCIA System Architecture, PowerPC System Architecture, Plug-and-Play System Architecture, CardBus System Architecture, Protected Mode Software Architecture, Pentium Pro and Pentium II System Architecture, USB System Architecture, FireWire System Architecture, PCI-X System Architecture, and AGP System Architecture The book series is published by Addison-Wesley Rather than duplicating common information in each book, the series uses the building-block approach ISA System Architecture is the core book upon which the others build Table 1 on page 1 illustrates the relationship of the books to each other Cautionary Note The reader should keep in mind that MindShare's book series often deals with rapidly-evolving technologies This being the case, it should be recognized that the book is a "snapshot" of the state of the targeted technology at the time that the book was completed We attempt to update each book on a timely basis to reflect changes in the targeted technology, but, due to various factors (waiting for the next version of the spec to be "frozen," the time necessary to make the changes, and the time to produce the books and get them out to the distribution channels), there will always be a delay Specifications This Book is Based On This book is based on the Universal Serial Bus 20 specification Organization of This Book The book is divided into sixpartsand contains the chapters listed below: Part I: Overview of USB 20 Chapter 1: This chapter provides an overview of the primary concepts of USB transfers and describes the interaction between USB system software, system hardware, and USB devices for USB 1x systems and USB 20 system The USB communications process is described, including the concept of the device framework Each hardware and software element in a USB system is introduced and its primary functions are described Chapter 2: This chapter provides an overview of the primary concepts of USB transfers and describes the interaction between USB system software, system hardware, and USB devices for USB 1x systems and USB 20 system The USB communications process is described, including the concept of the device framework Each hardware and software element in a USB system is introduced and its primary functions are described Chapter 3: USB defines a single connector type for attaching all USB peripherals to the host system This chapter introduces the physical aspects of USB connectors and cables Chapter 4: This chapter discusses USB power distribution, along with issues related to bus powered devices and the operation of self-powered devices The chapter also discusses the role of host software in detecting and reporting power related problems Part II: The USB Solution Chapter 5: USB employs NRZI encoding and differential signaling to transfer information across USB cables This chapter discusses the low- and full-speed signaling environment, including the differential signaling and NRZI encoding techniques used by the USB The signaling environment must also support a wide range of other signal-related functions such as: detecting device attachment and removal, suspending and resuming operation, resetting a device, and others all of which are discussed in this chapter Chapter 6: USB supports four transfer types: interrupt, bulk, isochronous, and control These transfer types and the process used to initiate and perform them are described in this chapter Chapter 7: Every transfer broadcast over the USB consists of a combination of packets These packets are combined to define individual transactions that are performed as part of a larger transfer Each transaction type is defined, along with the individual packets that comprise them Chapter 8: Interrupt, Bulk, and Isochronous transfers require that the successful delivery of data be verified by USB CRC and other error checking is performed to verify data delivery and if errors occur retries of the failed transmission are performed This chapter discusses the various sources of errors and the error detection mechanisms used by USB to identify them, and the error recovery that is performed to overcome them Chapter 9: USB devices support power conservation by entering a suspended state This chapter discusses the ways that devices are placed into the suspended state under software control It also discusses how software re-awakens devices, and how a device such as a modem can initiate a wakeup remotely Part III: High Speed Device Operation Chapter 10: This chapter provides a brief introduction to high-speed device operation and set the stage for a detailed discussion of the high-speed environment Chapter 11: High-speed capable devices must also be able to communicate in the full-speed signaling environment High-speed devices add many extensions to the full-speed environment to permit reliable signaling at a 480Mb/s rate This chapter introduces the principles associated with USB high-speed signalling and the methods used to switch between full- and high-speed operation Chapter 12: This chapter introduces the changes brought about by high-speed transmission rates The transfers defined in USB 10 have the same primary characteristics in the high-speed environment However, packet sizes and differences in signaling change accounts for some change Also, new features have been added to the high-speed environment such as high-bandwidth transfers and ping protocol These and other changes are review in this chapter Chapter 13: Error detection and handling during high-speed transactions is very similar in concept to the low- and full-speed error detection methods However, due to the faster clock rates several of the timing parameters must be changed to support error detection implementations such as timout values and babble detect Chapter 14: This chapter discusses the changes required for high-speed devices to use the full-speed suspend and resume protocol and signaling conventions Part IV: USB 20 Hub Operation with LS/FS/HS Devices Chapter 15: This chapter introduces the primary characteristic of a high-speed hub It must be able to operate when attached to both full-speed and high-speed ports, and must support all device speeds on its ports Chapter 16: This chapter discusses the 20 hubs behavior when it receives high-speed packets on its upstream and downstream ports This chapter details the operation of the high-speed repeater and discusses the delays associated with forwarding high-speed packets across the hub Chapter 17: This chapter introduces the concept of split transactions that allow high-speed hubs to support low- and full-speed devices without sacrificing large amounts of bus time required to access the slower devices The operation of the transaction translator is described, along with the various forms of split transaction and the specific sequences employed by each Part V: USB Configuration Chapter 18: This chapter provides an overview of the configuration process Each of the major steps involved in USB device enumeration are defined and discussed Chapter 19: This chapter discusses configuration of USB devices that are attached to any USB port The process is virtually the same for devices of any speed Device descriptors and other characteristics and features that relate to configuring the device are also detailed and discussed Chapter 20: Hub devices are configured like any other device attached to a USB port Hub configuration differs in that it involves reporting whether or not other devices are attached to the downstream ports This chapter review the hub configuration process with the focus on the issues related to extending the bus through the hub's downstream facing ports Chapter 21: This chapter introduces the concept of device classes and discusses their role within the USB This chapter discusses the first five class types that were defined These class are discussed to provide the reader with a sense of the information defined for each class and the USB mechanisms that they use A detailed discussion of device classes requires in-depth knowledge in the associated field such as telephony and audio Part VI: USB Software Chapter 22: Host software consists of three types of components: the USB Device Drivers, the USB Driver, and the Host Controller Driver This chapter discusses the role of each of these layers and describes the requirements of their programming interface Who Should Read this Book This book is intended for use by hardware and software design and support personnel Those individuals working outside of the design field may also find the text useful Prerequisite Knowledge The reader should be familiar with PC Architectures and legacy hardware and software issues MindShare's ISA System Architecture book provides foundation material that describes the legacy issues Visit Our Web Page Our web site contains a listing of all of our courses and books In addition, it contains errata for a number of the books, a hot link to our publisher's web site, as well as course outlines wwwmindsharecom Our publisher's web page contains a listing or our currently-available books and includes pricing and ordering information Their home page is accessible at: wwwawcom/cseng

IDDM: Intrusion Detection Using Data Mining Techniques

Abstract: : The IDDM project aims to determine the feasibility and effectiveness of data mining techniques in real-time intrusion detection and produce solutions for this purpose. Traditionally, data mining is designed to operate on large off-line data sets. Previous attempts to apply the discipline in real-time environments met with varying success. In this paper, we overview earlier attempts to employ data mining principles in intrusion detection and present a possible system architecture for this purpose. As a consequence, we show that by combining data mining algorithms with agent technologies, near real-time operation may be attained.

An industrial process control data access server supporting multiple client data exchange protocols

Abstract: A method and process control data server system architecture are disclosed for providing process data to a variety of client applications via a plurality of differing data sharing standards. The system architecture incorporates a ready platform for subsequently added client application data exchange protocols. In an exemplary embodiment, a set of standard interface definitions between client application data exchange protocol-specific plugins and a data access server engine supports incorporating new client application data exchange protocols by means of plugins designed to interface with the data access server engine according to the standard interface definitions.

Programming for Pervasive Computing Environments

Abstract: Pervasive computing provides an attractive vision for the future of computing. Computational power will be available everywhere. Mobile and stationary devices will dynamically connect and coordinate to seamlessly help users in accomplishing their tasks. However, for this vision to become a reality, developers must build applications that constantly adapt to a highly dynamic computing environment. To make the developers’ task feasible, we introduce a system architecture for pervasive computing, called one.world . Our architecture provides an integrated and comprehensive framework for building pervasive applications. It includes a set of services, such as service discovery, checkpointing, migration, and replication, that help to structure applications and directly simplify the task of coping with constant change. We describe the design and implementation of our architecture and present the results of an evaluation, which includes two case studies.