架空跨海电缆净空高度动态监测系统设计

根据架空跨海电缆的特点,设计了一种以单片机为中心的净空高度动态监测系统。文中给出了一些主要硬件模块的设计方法和GPS数据的解析程序。经实验测试,该系统能有效地保证电缆的安全运行。     

Software engineering and production monitoring systems

Software that is to be designed and written for operation in the factory environment is especially difficult to conceptualize, design and successfully install. This paper focuses on some aspects of software engineering that apply to this situation and may prove useful to others involved in this profession. The particular problem that is considered in the paper is that of a Real-time Production Monitoring System although any industrial system could have been used. Monitoring industrial processes and displaying meaning ful data in real-time is extremely difficult, mainly because each component, although complementary, is functionally, electrically and temporally quite different. It is therefore difficult to design a standard factory data structure or always to find elegant processing mechanisms. In order to integrate data from these disparate sources, the system must be carefully architected, using consistent and sound software engineering principles.The paper included practical aspects of the implementation of this particular information system, which is a growing component in the management process of a typical computer-integrated manufacturing facility. The paper contains sections on human-factors engineering, fault detection and system recovery. The selection of the operating system platform is critical, and software engineering professionals should appreciate the sections devoted to the system components. Some material is based on the author's own practical experience gained in the design and implementation of several such systems.     

Software monitoring through formal specification animation

This paper presents a formal specification-based software monitoring approach that can dynamically and continuously monitor the behaviors of a target system and explicitly recognize undesirable behaviors in the implementation with respect to its formal specification. The key idea of our approach is in building a monitoring module that connects a specification animator with a program debugger. The requirements information about expected dynamic behaviors of the target system are gathered from the formal specification animator, while the actual behaviors of concrete implementations of the target system are obtained through the program debugger. Based on the information obtained from both sides, the judgement on the conformance of the concrete implementation with respect to the formal specification is made timely while the target system is running. Furthermore, the proposed formal specification-based software monitoring technique does not embed any instrumentation codes to the target system nor does it annotate the target system with any formal specifications. It can detect implementation errors in a real-time manner, and help the developers and users of the system to react to the problems before critical failure occurs.     

Systems with low distributed simulation overhead

Distributed simulation often involves a large number of overhead messages. This may lead to severe performance degradation of the simulator as pointed out in several previous works. In this work special classes of systems which can be simulated with low overhead-in most systems identified here the total number of overhead messages on any given communication line is at most one, irrespective of the time up to which the physical system is to be simulated-are presented. This includes acyclic systems, some closed queuing networks, some open cyclic queuing networks, and other special types of cyclic networks. Distributed simulation algorithms specially tailored to these systems are given. By isolating these classes of systems and designing distributed simulation algorithms specifically geared for them, a large number of overhead messages can be avoided. By contrast, other distributed simulation algorithms are usually designed for more general systems and they usually require too many overhead messages, even in simulating these special classes of systems     

可信可控网络中跨自治域的流合作测量模型

当前网络环境下提出的流测量算法缺少必要的合作,存在测量覆盖度不高等问题。为此,提出一种新的基于全网合作的流测量模型,在自治域(AS)间通过标识已测量流和共享测量结果的方式,实现AS间的流合作测量,在AS内利用控制节点为路由器统一分配测量任务的方法,实现AS内最大化流测量覆盖度的目标。实验结果表明,该模型能够有效利用网络资源,平衡各个路由器的测量负载,提高测量覆盖度,具有比以往方法更好的性能。     

安全性可控的生成式文本隐写算法

生成式文本隐写算法通过对候选池中的单词进行控制性选择映射来隐藏秘密信息,通常包含3个模块：文本生成模型、候选池概率分布截断和隐写嵌入算法。由于不同时刻文本生成模型输出的概率分布差异巨大,现有算法通常采用top-k或top-p对候选池单词的概率分布进行截断,以减少低概率的生成词,提高生成文本的安全性。当文本生成模型输出的候选池概率分布过于集中（over-concentrated）或过于平坦（over-flat）时,原有的top-k或top-p截断方式不足以应对概率分布的变化,容易产生概率较低的词或忽略概率较高的词,导致生成文本的安全性指标出现异常。针对此类问题,提出了安全性可控的生成式文本隐写算法,在候选池中根据秘密信息控制性选择生成词时,所提算法基于困惑度和KL散度的参数约束,动态进行候选池概率分布的截断,使候选池中所有单词都满足参数约束,提高了生成文本的安全性。实验结果表明,所提算法生成的隐写文本困惑度和KL散度可控;在相同KL散度情况下,生成文本的困惑度较现有算法下降最高达20%～30%;可以同时控制困惑度和KL散度,在指标合理的情况下,使生成的文本同时满足困惑度和KL散度两个指标...     

Incremental inconsistency detection with low memory overhead

Ensuring models’ consistency is a key concern when using a model‐based development approach. Therefore, model inconsistency detection has received significant attention over the last years. To be useful, inconsistency detection has to be sound, efficient, and scalable. Incremental detection is one way to achieve efficiency in the presence of large models. In most of the existing approaches, incrementalization is carried out at the expense of the memory consumption that becomes proportional to the model size and the number of consistency rules. In this paper, we propose a new incremental inconsistency detection approach that only consumes a small and model size‐independent amount of memory. It will therefore scale better to projects using large models and many consistency rules. Copyright © 2012 John Wiley & Sons, Ltd.     

Alignment materials with controllable anchoring energy

New polymers with photo‐controllable anchoring energy and tunable pretilt angle within 90°–0° range for nematic liquid crystals alignment were developed. The functional properties of polymers are provided by the effect of photoinduced planar alignment and the presence of side hydrocarbon chains in macromolecules that create a homeotropic alignment effect. Applying photosensitive alignment layers based on polymers with side benzaldehyde and hydrocarbon groups, fabrication of optical devices with refractive index gradient, uniform cell gap, and low operation voltage is possible. The developed materials are suitable for simple fabrication of tunable liquid crystal lenses.     

一种视频设备流量监测软件的设计

针对在研的视频数字化设备开发了一种视频流量监测系统。该系统采用微软MFC的API技术设计,通过通信接口接收流量信息,并经信号处理后实时显示视频设备的流量信息。应用结果表明,该监测系统运行稳定可靠,监测精度高,具有一定的实用性和推广价值。     

基于攻击威胁监控的软件保护方法

为了增加软件逆向分析的难度,提高软件的安全性,提出了一种基于攻击威胁监控的软件保护方法。该方法通过在软件中部署威胁监控网,来实时检测并处理软件执行过程遇到的多种攻击威胁,确保软件处于一个相对安全的执行环境中,难以被逆向分析。对该保护方法的研究,主要分为以下三个方面：1）攻击威胁描述。分析软件面临的潜在攻击威胁,并按照<威胁目的,实施方式,作用对象>的表示方式对每种威胁进行描述。2）攻击威胁监控网部署。分析各种威胁的特点并设计对应的检测方法,生成节点库;根据节点自身特点,选取合理的部署方案,将节点安插到软件的不同位置。3）原型系统实现与实验设计。按照保护方案的思路实现原型系统,保护一组程序实例,对提出的方案从性能损耗和安全性影响两方面来评估,实验分析结果表明该保护方案是可行且有效的。     

基于层次包围盒的车辆位置实时监控软件设计

在车辆位置合法性实时判断中根据系统特点选用了层次包围盒化简运算。具体设计中首先提出了上位机和下位机协同工作的策略,引入了“适时终止”机制,并详细分析了算法的性能。通过实验证明此方法可以有效地解决在低成本车载端实现车辆位置实时监控的难题。     

基于函数级控制流监控的软件防篡改

软件防篡改是软件保护的重要手段。针对由缓冲区溢出等攻击导致的控制流篡改,提出一种基于函数级控制流监控的软件防篡改方法。以函数级控制流描述软件正常行为,利用二进制重写技术在软件函数入口处植入哨兵,由监控模块实时获取哨兵发送的软件运行状态,通过对比运行状态和预期值判断程序是否被篡改。实现了原型系统并对其进行了性能分析,实验结果表明,基于函数级控制流监控的软件防篡改方法能有效检测对控制流的篡改攻击,无误报且开销较低,其实现不依赖程序源码,无需修改底层硬件和操作系统,监控机制与被保护软件隔离,提高了安全性。     

Unreliable multi-server system with controllable broadcasting service

Consideration was given to the multi-server queuing system with an infinite buffer. The customer arrivals obey a Markov arrival flow, the time of customer service having a phasetype distribution. service may be done with errors. If at the instant of customer arrival the number of busy servers is less than some threshold, then the customer is copied to all free servers which service it. If at that instant the number of busy servers is not less than some threshold, then the customer is serviced by a single server. The stationary distribution of the number of customers and their sojourn time were determined. The impact of the threshold value on the probability of successful service of the customer was studied numerically.     

具有形状控制的参数的角点磨光

提出了一种改进的空间剖分,在这个空间剖分上可以构造分片磨光曲面。最终得到低次的磨光曲面。更为重要的是,存在一些自由参数来控制磨光区域的大小和调整磨光曲面的形状。提供了一些例子显示磨光的效果。     

Closed multiresource queueing systems with controllable priorities

The paper investigates a closed queue model with controllable priorities in which the customers require a random number of channels simultaneously. A technique for aggregation of phase space states is proposed, reducing the dimension of the problem. Numerical examples are presented.Translated from Kibernetika, No. 5, pp. 90–93, September–October, 1989.     

Optimization of linear systems with controllable coefficients

Consideration was given to the characteristic properties of the linear differential equations with controllable coefficients, their dynamic invariants and constraints on the reachability domain that are important for the problems of control, properties of the Pontryagin extremals of this class, and numerical methods of control optimization.     

基于GPRS的远程心电实时监护仪软件系统设计

针对远程心电实时监护的特殊要求设计的监护仪软件系统,实现了心电实时监护、医嘱短信收发、监护状态显示、紧急求救报警等功能。     

Traceband: A fast,low overhead and accurate tool for available bandwidth estimation and monitoring

Available bandwidth estimation techniques are being used in network monitoring and management tools to provide information about the utilization of the network and verify the compliance of service level agreements. However, the use of these techniques in other applications and network environments is limited by the long convergence times, accuracy errors, and the amount of overhead that they introduce. In this paper, we introduce Traceband, a hidden Markov model-based technique for end-to-end available bandwidth estimation and monitoring that improves these performance metrics and therefore promises to expand the use of these techniques in other scenarios. Traceband is evaluated and compared with Spruce and Pathload using Poisson and self-similar cross-traffic. Experimental results in a controlled environment with Poisson cross-traffic demonstrate that Traceband is as accurate as Spruce and Pathload but considerably faster, and introduces less overhead. Traceband’s convergence time is demonstrated using bursty cross-traffic, as it is the only tool that accurately reacts to zero-traffic periods, which may be particularly useful for those applications that need to make decisions in real time. Using self-similar traffic, Traceband’s mean accuracy and variability degrade with the Hurst parameter but it still performs within reasonable limits. A general and optional moving average algorithm is also introduced to solve these issues.     

A Spark-based Apriori algorithm with reduced shuffle overhead

The Journal of Supercomputing - Mining frequent itemset is considered as a core activity to find association rules from transactional datasets. Among the different well-known approaches to find...