Synthetic Floating-Point (SFP), a synthetic benchmark generator program for floating-point circuits is presented. SFP consists of two independent modules for characterisation and generation. The characterisation modul...
详细信息
Synthetic Floating-Point (SFP), a synthetic benchmark generator program for floating-point circuits is presented. SFP consists of two independent modules for characterisation and generation. The characterisation module extracts key dataflow statistics of an arbitrary software program. Generation involves producing randomised circuits with desired statistics which are either the output of the characterisation module or directly generated by the user. Using the basic linear algebra subprograms (BLAS) library, Whetstone benchmark and LINPACK benchmark, it is demonstrated that SFP can be used to generate floating-point benchmarks with different user-specified properties as well as benchmarks that mimic real computational programs.
distributed embedded softwaresystems, such as sensor networks and command and control systems, are complex systems with stringent performance, reliability, security, and safety constraints. These are also long-lived ...
详细信息
distributed embedded softwaresystems, such as sensor networks and command and control systems, are complex systems with stringent performance, reliability, security, and safety constraints. These are also long-lived systems that must be continually upgraded and evolved to incorporate enhanced functionality. One approach for achieving high quality and evolvability for these systems is to organize them in the form of application-oriented frameworks that allow the system to be composed from orthogonal aspects that can be independently developed, evolved, and certified. In this paper, we define a general framework that allows a distributed embedded system to have relatively independent aspects, including "plug-and-play" capability. We present conditions under which the reliability of the system can be inferred from the reliability of the individual aspects. The approach is illustrated for a framework-based distributed sensor network.
This paper presents the technique of manipulating FPGA configuration in fine granularity to improve the efficiency of incremental design. The main contributions are achieving hardware autonomy and enhancing hardware d...
详细信息
ISBN:
(纸本)9781479913725
This paper presents the technique of manipulating FPGA configuration in fine granularity to improve the efficiency of incremental design. The main contributions are achieving hardware autonomy and enhancing hardware development productivity, demonstrated by two categories of applications: implementing Autonomous Adaptive systems and Fast System Progotyping. Vendor tools provide limited facilitation for these applications. For the first category, a system with a universal UART transmitter is demonstrated on the ML410 FPGA board. The BAUD rate generating circuit is autonomously modified in hardware to adapt to the requirement of a remote UART receiver. For the second category, fast module assembly for prototyping a GNU Radio system is demonstrated on the XUPV5-LX110T FPGA board. Its run-time is tens of times faster than that of the vendor tool. Moreover, to evaluate the quality of the proposed fine-grained manipulation, wire delay information is approximated through brute-force analysis. The delay estimation result achieves accuracy within 6% error as compared to that of the vendor tool's.
This paper presents simulated results comparing representatives of two approaches to software DSM: an object-based protocol and a page-based protocol. We explore the performance implications of each approach, includin...
详细信息
This paper presents simulated results comparing representatives of two approaches to software DSM: an object-based protocol and a page-based protocol. We explore the performance implications of each approach, including the object approach's advantages in bandwidth consumption and lack of false sharing. Somewhat surprisingly the locality and data aggregation advantages of page-based systems prove to be the dominant factors with typical operating system overheads. We show that large page sizes actually improve the performance of multiwriter protocols, primarily because validating a single object validates all order objects on the same page as well. Since our applications have significant spatial locality, these additional validates reduce the number of remote misses, without significantly increasing bandwidth requirements. For three out of the four applications we tested, our page-based protocol matched or outperformed our object-based protocol under typical operating systems costs. We quantify this effect, and conclude with a discussion of techniques that could allow each approach to benefit from the best features of the other.
Reprogramming is an essential service for wireless sensor networks. Authenticating reprogramming process is important as sensors need to verify that the code image is truly from a trusted source. There are two ways to...
详细信息
Reprogramming is an essential service for wireless sensor networks. Authenticating reprogramming process is important as sensors need to verify that the code image is truly from a trusted source. There are two ways to achieve authentication: public key based and symmetric key based. Although previous work has shown that public key authentication is feasible on sensor nodes if used sparingly, it is still quite expensive compared to symmetric key based approach. In this paper, we propose a symmetric key based protocol for authenticating reprogramming process. Our protocol is based on the secret instantiation algorithm from, which requires only O(log n) keys to be maintained at each sensor. We integrate this algorithm with the existing reprogramming protocol. Through simulation, we show that it is able to authenticate reprogramming process at very low communication cost, and has very short delay.
Summary form only given. Desktop resources are attractive for running compute-intensive distributed applications. Several systems that aggregate these resources in desktop grids have been developed. While these system...
详细信息
Summary form only given. Desktop resources are attractive for running compute-intensive distributed applications. Several systems that aggregate these resources in desktop grids have been developed. While these systems have been successfully used for many high throughput applications there has been little insight into the detailed temporal structure of CPU availability of desktop grid resources. Yet, this structure is critical to characterize the utility of desktop grid platforms for both task parallel and even data parallel applications. We address the following questions: (i) What are the temporal characteristics of desktop CPU availability in an enterprise setting? (ii) How do these characteristics affect the utility of desktop grids? (iii) Based on these characteristics, can we construct a model of server "equivalents" for the desktop grids, which can be used to predict application performance? We present measurements of an enterprise desktop grid with over 220 hosts running the Entropia commercial desktop grid software. We utilize these measurements to characterize CPU availability and develop a performance model for desktop grid applications for various task granularities, showing that there is an optimal task size. We then use a cluster equivalence metric to quantify the utility of the desktop grid relative to that of a dedicated cluster.
Increasing demands on safety and energy efficiency will require higher levels of automation in transportation systems. This involves dealing with safety-critical distributed coordination. In this paper we demonstrate ...
详细信息
Optimal scheduling of tasks of a directed acyclic graph (DAG) onto a set of processors is a strong NP-hard problem. In this paper we present a scheduling scheme called TDS to schedule tasks of a DAG onto a heterogeneo...
详细信息
Optimal scheduling of tasks of a directed acyclic graph (DAG) onto a set of processors is a strong NP-hard problem. In this paper we present a scheduling scheme called TDS to schedule tasks of a DAG onto a heterogeneous system. This models a network of workstations, with processors of varying computing power. The primary objective of this scheme is to minimize schedule length and scheduling time itself. The existing task duplication based scheduling scheme is primarily done for totally homogeneous systems. We compare the performance of this algorithm with an existing scheduling scheme for heterogeneous processors called BIL. In initial simulations TDS has been observed to generate scheduling lengths shorter than that of BIL, for communication-to-computation cost ratios (CCR) of 0.2 to 1. Moreover TDS is far more superior than BIL as far as scheduling time is concerned.
The design and use of multi-stakeholder distributedsystems (MSDSs — in which nodes are designed or operated by distinct stakeholders having limited knowledge and possibly conflicting goals) challenge our tr...
ISBN:
(数字)9783540457893
ISBN:
(纸本)3540442359
The design and use of multi-stakeholder distributedsystems (MSDSs — in which nodes are designed or operated by distinct stakeholders having limited knowledge and possibly conflicting goals) challenge our traditional conceptions of requirements engineering and system validation in two ways. First, global inconsistency among high-level requirements forces us to focus on the personalized and time sensitive requirements of a single stakeholder, rather than the more traditional global, time-invariant requirements. Second, any given stakeholder will typically lack detailed knowledge of the behaviors of nodes not under his control; such knowledge is necessary to validating requirements conformance. OpenModel [1] is a research effort whose aim is to address this ”ignorance problem” through open, standardized behavioral modeling. In OpenModel, each node of an MSDS such as the Internet email system or a network of web services provides via http (or through a central registry) a behavioral model expressed in terms of shared domain-specific function/object theories. By assembling these models appropriately, tools based upon techniques like scenario simulation, animation, coverage measurement, theorem proving, and model checking can support a wide range of automated softwareengineering activities: personalized requirements engineering, validation, on-line help, node design, configuration, and evolution.
暂无评论