Testing the Schedulability of Synchronous Traffic for the Timed Token Medium Access Control Protocol

One of the key issues related to guaranteeing synchronous message deadlines in a timed token network (such as fiber distributed data interface) where the timed token medium access control protocol is used is the schedulability test of synchronous traffic (i.e., testing whether or not all synchronous messages can be transmitted before their deadlines, under a given setting of network parameters). Much work has been done on how to assign network parameters appropriately in order to guarantee timely transmission of synchronous traffic. As a result quite a few synchronous bandwidth allocation schemes and some good guidelines on selection of the target token rotation time have been proposed. In contrast, limited research has been conducted on how to effectively test whether or not given network parameters can guarantee timely transmission of all synchronous messages (of a considered synchronous message set) before their deadlines. The previous testing methods for synchronous message schedulability only provide a sufficient (but not necessary) test and therefore fail to always keep effective for any synchronous message set considered. In this paper, we propose two testing methods for determining the schedulability of a synchronous message set with message deadlines no longer than periods. The proposed tests perform better than any previous test in the sense that they are both sufficient and necessary. Some numerical examples are given to compare different testing methods, all of which have demonstrated the superiority of the proposed tests to other existing testing methods.     

Use of oscillating waterbeds and rhythmic sounds for premature infant stimulation.

22 healthy infants born at gestational ages of 28–32 wks were randomly assigned to experimental or control groups within the 1st 4 days following birth. Experimental Ss were placed in incubators equipped with oscillating waterbeds and rhythmic sounds; control Ss were placed in traditional incubators. Results indicate that general developmental progress was enhanced in the experimental group by the stimulation procedure. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Liquid‐crystal displays using printed plastic TFT backplanes

Abstract— In this paper, we present results from a new liquid crystal over plastic printed thin‐film‐transistor (TFT) display. The display demonstrator shows that the processing incompatibilities between the plastic TFT backplane and the liquid‐crystal materials can be addressed to make a stable twisted‐nematic structure. New fabrication processes such as the photo‐alignment of liquid crystals have made it possible to create a new generation of displays, which pave the way towards fully integrated plastic liquid‐crystal‐display technologies.     

WCET Analysis of Superscalar Processors Using Simulation With Coloured Petri Nets

Determining a tight WCET of a block of code to be executed on a modern superscalar processor architecture is becoming ever more difficult due to the dynamic behaviour exhibited by current processors, which include dynamic scheduling features such as speculative and out-of-order execution in the context of multiple execution units with deep pipelines. We describe the use of Coloured Petri Nets (CP-nets) in a simulation based approach to this problem. A complex model of a generic processor architecture is described, with emphasis on the modelling strategy for obtaining the WCET and an analysis of the results.     

Interior Penalties for Summation-by-Parts Discretizations of Linear Second-Order Differential Equations

This work focuses on simultaneous approximation terms (SATs) for multidimensional summation-by-parts (SBP) discretizations of linear second-order partial differential equations with variable coefficients. Through the analysis of adjoint consistency and stability, we present several conditions on the SAT penalties for general operators, including those operators that do not have nodes on their boundary or do not correspond with a collocation discontinuous Galerkin method. Based on these conditions, we generalize the modified scheme of Bassi and Rebay and the symmetric interior penalty Galerkin method to SBP-SAT discretizations. Numerical experiments are carried out on unstructured grids with triangular elements to verify the theoretical results.     

NFS-CD: Write-Enabled Cooperative Caching in NFS

We present the network file system with cluster delegation (NFS-CD), an enhancement to the NFSv4 that reduces server load and increases the scalability of distributed file systems in computing clusters. The cluster delegation feature of NFS-CD allows data sharing among clients by extending the NFSv4 delegation model so that multiple clients manage a single file without interacting with the server. Based on cluster delegation, we implement a fast-commit primitive, cooperative caching, and the ability to recover the uncommitted updates of a failed computer. NFS-CD supports both read and write operations in the cooperative cache without degrading the consistency model of NFSv4. We have implemented NFS-CD by modifying the Linux NFSv4 client only. Because the server remains unchanged, NFS-CD preserves the simple administration model of NFSv4 and interoperates with standard NFS clients. NFS-CD offers improved performance when compared to NFSv4 at the expense of slightly weaker reliability guarantees. An experimental evaluation of our implementation, using industry standard benchmarks and application workloads, reveals that NFS-CD reduces server load by more than half. It also demonstrates that under most workloads, file systems must support writes to the cooperative cache to achieve scale.     

Contributions from cognitive engineering to requirements specifications for complex sociotechnical systems: A case study in the context of healthcare in Brazil

This paper aims at presenting a case study on the use of human factors and ergonomics to enhance requirement specifications for complex sociotechnical system support tools through enhancing the understanding of human performance within the business domain and the indication of high‐value requirements candidates to information technology support. This work uses methods based on cognitive engineering to build representations of the business domain, highlighting workers’ needs, and contributing to the improvement of software requirements specifications, used in the healthcare domain. As the human factors discipline fits between human sciences and technology design, we believe that its concepts can be combined with software engineering to improve understanding of how people work, enabling the design of better information technology.     

Achieving greater anonymity in network latency

Each lnternet communication leaves trails that can be followed back to the user. Notably, anonymous communication schemes are purposed to hide users＇ identity as to personal, source, destination location and content information. Notably, no network capability is in existence to completely negate anonymity leakage in network latency[~l, thus, the minimization of anonymity leakage in network latency becomes critically salient. The purpose of this paper is to investigate network latency anonymity leaks, and propose practical techniques for their reduction. In this direction, the author investigate the following technical question： What implementation techniques can be configured to truly reduce anonymity leaks using deployable systems and exploiting the popular Tor security strategies.     

An engineering process for the verification of real-time systems

The complete verification of the timing properties of a large critical system cannot be undertaken in a single step or with a single method. In this paper we present a process that links together a number of techniques and approaches that cover all stages of development from requirements analysis to code testing. The key elements of the process are: a constrained form of timed automata that uses delay and deadline to define temporal behaviour, notions of rely and guarantee to cover temporal dependencies, model checking for design verification, SPARK and Ravenscar restrictions for programming, and scheduling and response time analysis for asserting implementation compliance. Extended examples of the use of the process are given.