修正的ISI法及其应用

针对本质安全指标(ISI)灵敏性不强,指标区间不连续,评价方式较片面等缺点,对ISI的指标取值方法和评价模式进行了修正.通过建立指标区间函数,提高了指标的灵敏性,实现了指标区间的连续化;根据事故演变情形,提出了改良的评价模式,并增加了危害指标、诱变指标和事故指标,分别反映过程潜在的危害因素、诱变因素和事故情形;分别用ISI和ISIM对EDC过程实例的2个路径,即直接氯化法和氧氯化法,进行了评价和比较,ISI的评价结果分别为29和32,MISI评价结果中,危害指标分别为1 232.4和1745.8,诱因指标分别为5.83和7.45,事故指标分别为277.1和751.1,表明MISI法的评价结果更加符合实际过程信息,同时从危害、诱变和事故3个方面反映过程的安全特征.     

Discrimination with Spike Times and ISI Distributions

We study the discrimination capability of spike time sequences using the Chernoff distance as a metric. We assume that spike sequences are generated by renewal processes and study how the Chernoff distance depends on the shape of interspike interval (ISI) distribution. First, we consider a lower bound to the Chernoff distance because it has a simple closed form. Then we consider specific models of ISI distributions such as the gamma, inverse gaussian (IG), exponential with refractory period (ER), and that of the leaky integrate-and-fire (LIF) neuron. We found that the discrimination capability of spike times strongly depends on high-order moments of ISI and that it is higher when the spike time sequence has a larger skewness and a smaller kurtosis. High variability in terms of coefficient of variation (CV) does not necessarily mean that the spike times have less discrimination capability. Spike sequences generated by the gamma distribution have the minimum discrimination capability for a given mean and variance of ISI. We used series expansions to calculate the mean and variance of ISIs for LIF neurons as a function of the mean input level and the input noise variance. Spike sequences from an LIF neuron are more capable of discrimination than those of IG and gamma distributions when the stationary voltage level is close to the neuron's threshold value of the neuron.     

CTW: an integrated computer and telephone‐accessed WWW system

This work presents the development of an integrated computer and telephone‐accessed WWW system (CTW) to provide a ubiquitous web access service. The CTW system serves as an intermediary between the telephone user and web sites. The CTW system retrieves and then converts the proposed Hyper Phone Markup Language (HPML) specified web pages into speech patterns. Telephone users can access information, including form‐based transaction services, on HPML‐specified web pages using a telephone set anywhere in the world by connecting to the CTW system. Another feature of CTW is that HPML‐ specified web pages stored in cyberspace can also be accessed via regular browsers, including the current Netscape Navigator and Microsoft Internet Explorer. The CTW system provides a ubiquitous web access service for users at any degree of web‐literacy by integrating well‐installed telephone networks and the Internet. Copyright © 2000 John Wiley & Sons, Ltd.     

Structured analysis of the ISI Atomic Pair Actions dataset using workflows

Understanding pair-wise activities is an essential step towards studying complex group and crowd behaviors in video. However, such research is often hampered by a lack of datasets that concentrate specifically on Atomic Pair Actions; [Here, we distinguish between the atomic motion of individual objects and the atomic motion of pairs of objects. The term action in Atomic Pair Action means an atomic interaction movement of two objects in video; a pair activity, then, is composed of multiple actions by a pair or multiple pairs of interacting objects ( and ). Please see Section 1 for details.] in addition, the general dearth in computer vision of a standardized, structured approach for reproducing and analyzing the efficacy of different models limits the ability to compare different approaches. In this paper, we introduce the ISI Atomic Pair Actions dataset, a set of 90 videos that concentrate on the Atomic Pair Actions of objects in video, namely converging, diverging, and moving in parallel. We further incorporate a structured, end-to-end analysis methodology, based on workflows, to easily and automatically allow for standardized testing of state-of-the-art models, as well as inter-operability of varied codebases and incorporation of novel models. We demonstrate the efficacy of our structured framework by testing several models on the new dataset. In addition, we make the full dataset (the videos, along with their associated tracks and ground truth, and the exported workflows) publicly available to the research community for free use and extension at <http://research.sethi.org/ricky/datasets/>.     

一种ISI信道的联合定时恢复算法

通过研究Viterbi算法的特性,本文采用了一种新的联合定时恢复方法,能同时进行序列检测和定时恢复,适用于低信噪比的ISI信道,具有效率高、延时小、实时跟踪的特点。仿真结果表明即使在检测器的误彼特率高于10-2时算法仍能很好的工作。     

基于无线信道的软干扰抵消Turbo均衡技术研究

介绍了应用于无线信道的Turbo均衡技术,针对MAP均衡算法的计算复杂度较高,提出了一种改进的基于软干扰抵消(SIC)的turbo均衡算法,该方法运用信道译码器输出的全部信息做先验信息进行迭代传递,充分利用了软信息;在给定的无线信道下进行了仿真与分析,仿真结果表明,在不增加计算复杂度的情况下,改进的SIC算法与传统SIC算法相比,在误码率为10-4时性能有近1.5dB的性能增益,与MAP均衡算法性能相近,有效地提高了通信可靠性。     

Simulation study of molecular communication systems with an absorbing receiver: Modulation and ISI mitigation techniques

The research activities on Molecular Communication via Diffusion (MCvD) that can interconnect nanomachines, heavily depend on simulations to verify and evaluate the new communication paradigm. The existing simulation tools cannot be directly used for MCvD systems since the diffusion channel has different characteristics compared to classical communication channels. In an MCvD system, diffusion and demodulation processes have their own constraints and characteristics due to the impossibility of sending a negative number of molecules, the random movement of molecules, and a reception process of molecules that determines the signal. Therefore, a custom end-to-end MolecUlar CommunicatIoN (MUCIN) simulator for MCvD systems is presented. Compared to other simulators available in the literature, MUCIN simulator is an end-to-end simulator that considers first hitting process for the signal reception. It supports 1-D to 3-D environments, sending consecutive symbols, imperfect molecule reception, extendable modulation, and filtering modules. MUCIN simulator source code is available under BSD licensing for contributors from the nanonetworking community. Following the simulator analysis, a case study of inter-symbol-interference mitigation that utilizes the decision in one previous slot is introduced. The contribution of this paper is twofold; one is the modeling and the development of an end-to-end MCvD simulator, the other is the performance evaluation of the proposed inter-symbol interference filtering and demodulation techniques.     

The MESM and the monastery

The first electronic digital computer in continental Europe was constructed not in Germany or France, but in the Ukraine. In the late 1940s, Sergei Alexeevich Lebedev began constructing the MESM (Malaya Elektronaya Schetnaya Mashina, or Small Electronic Calculating Machine). Although computer historians G.D. Crowe and S. Goodman (1994) trace the early career and work of Sergei Alexeevich Lebedev and the creation of the MESM in fine detail, many of the events and culture that surrounded this project deserve a closer look. The authors describe some of them     

The profession and the world

Professionals have a responsibility to use their skills and experience where relevant to judge the nature and reality of problems facing their community and to promote and support solutions to those problems. This responsibility distinguishes professionals from people who ply a trade. The paper considers how a computing professional's skills and experience are particularly relevant to the community. We can apply traditional systems analysis to the global problems we encounter, and digital technology has undoubted potential for supporting good solutions to many of these problems. How a systems analyst will look professionally at the world's purpose will depend on who she sees as having the problem. As the employee of a client, the systems analyst will take a materialist approach. But as a professional primarily responsible to the community, that same systems analyst will take a demotic approach.     

The Spider and the Web

No abstract available for this article.