A simulated annealing algorithm for dynamic layout problem

Increased level of volatility in today's manufacturing world demanded new approaches for modelling and solving many of its well-known problems like the facility layout problem. Over a decade ago Rosenblatt published a key paper on modelling and solving dynamic version of the facility layout problems. Since then, various other researchers proposed new and improved models and algorithms to solve the problem. Balakrishnan and Cheng have recently published a comprehensive review of the literature about this subject. The problem was defined as a complex combinatorial optimisation problem. The efficiency of SA in solving combinatorial optimisation problems is very well known. However, it has recently not been applied to DLP based on the review of the available literature. In this research paper a SA-based procedure for DLP is developed and results for test problems are reported.

Scope and purpose

One of the characteristic of today's manufacturing environments is volatility. Under a volatile environment (or dynamic manufacturing environment) demand is not stable. To operate efficiently under such environments facilities must be adaptive to changing demand conditions. This requires solution of the dynamic layout problem (DLP). DLP is a complex combinatorial optimisation problem for which optimal solutions can be found for small size problems. This research paper makes use of a SA algorithm to solve the DLP. Simulated annealing (SA) is a well-established stochastic neighbourhood search technique. It has a potential to solve complex combinatorial optimisation problems. The paper presents in detail how to apply SA to solve DLP and an extensive computational study. The computational study shows that SA is quite effective in solving dynamic layout problems.     

Computing Prime Factorization And Discrete Logarithms: From Index Calculus To Xedni Calculus

The integer factorization problem (IFP), the finite field discrete logarithm problem (DLP) and the elliptic curve discrete logarithm problem (ECDLP) are essentially the only three mathematical problems that the practical public-key cryptographic systems are based on. For example, the most famous RSA cryptosystem is based on IFP, the US government's Digital Signature Standard, DSS, is based on DLP, whereas the ECC (Elliptic Curve Cryptography) and Elliptic Curve Digital Signature Algorithm (ECDSA) are based on ECDLP. The security of such cryptographic systems relies on the computational intractability of these three mathematical problems. In this paper, we shall present a survey of various methods for solving the IFP/DLP and particularly the ECDLP problems. More specifically, we shall first discuss how the index calculus as well as quantum algorithms can be used to solve IFP/DLP. Then we shall show why the index calculus cannot be used to solve ECDLP. Finally, we shall introduce a new method, xedni calculus , due to Joseph Silverman, for attack ECDLP; some open problems and new research directions, will also be addressed.     

The Least Fixpoint Transformation for Disjunctive Logic Programs

The paradigm of disjunctive logic programming(DLP)enhances greatly the expressive power of normal logic programming(NLP)and many(declarative)semantics have been defined for DLP to cope with various problems of knowledge representation in artificial intelligence.However,the expressive ability of the semantics and the soundness of program transformations for DLP have been rarely explored.This paper defines an immediate consequence operatro T^GP for each disjunctive program and shows that T^GP has the least and computable fixpoint Lft(P),Lft is,in fact,a program transformation for DLP,which transforms all disjunctive programs into negative programs.It is shown that Lft preserves many key semantics,including the disjunctive stable models,well-founded model,disjunctive argunent semantics DAS,three-valued models,ect.Thic means that every disjunctive program P has a unique canonical form Lft(P)with respect to these semantics.As a result,the work in this paper provides a unifying framework for studying the expressive ability of various semantics for DLP On the other hand,the computing of the above semantics for negative programs is ust a trivial task,therefore,Lft(P)is also an optimization method for DLP.Another application of Lft is to derive some interesting semantic results for DLP.     

Removal of hot spot speckle on laser projection screen using both the running screen and the rotating diffuser

A running screen method is applied to remove hot spot speckle on projection screen by a laser display system with one DLP panel. We have commercially displayed a projection image from a DLP (720 Pi) display system using a minimized RGB high power laser source. Then we successfully obtained a high-quality image with low speckle contrast as if hot spot speckle are not recognized on the screen when both the rotating diffuser and the rotating screen by piezoelectric motor are used.     

DLP和LCD投影机对比分析

投影机是一种重要的计算机图形图像显示设备。本文从介绍投影机的分类入手,分别详细介绍分析了LCD和DLP两种主流投影机的工作原理,并且就这两种投影机的技术特点进行了性能对比分析。可以看出,数字化的DLP投影技术在许多方面是具有很大优势的。     

Parallelized deblocking filtering of HEVC decoders based on complexity estimation

This paper proposes a parallelization method for a deblocking filter in a high-efficiency video coding (HEVC) decoder based on complexity estimation. A deblocking filter of HEVC is generally considered to be appropriate for data-level parallelism (DLP) because there are no data-level dependencies among adjacent blocks in the horizontal and vertical filtering processes. However, an imbalanced workload can increase the idle time on some of the threads, and thus, the maximum parallel performance cannot be achieved with only DLP. To alleviate this problem, the proposed method estimates the computational complexity by utilizing the coding unit (CU) segment information and the on/off flag of the deblocking filter in advance. Then, the workload is distributed equally across all threads. The experimental results indicate that the proposed method can accelerate the decoding speed by a factor of 3.97, with six threads on top of the sequential deblocking filtering. In addition, the ratio of the maximum elapsed time to ideal elapsed time is reduced to approximately 21 %, as compared to conventional DLP-based parallel deblocking filtering methods that do not implement a complexity estimation method.     

双析取逻辑程序设计基础（Ⅰ）

析取逻辑程序设计是传统逻辑程序设计最重要的扩充之一，本文通过一些实例说明，现存语义无法充分 表示信息的不完全性。为此，本文提出了双析取逻辑程序设计的概念，我们不仅从句法上将正规则析取逻辑程序推广为双析取逻辑程序。而且建立了一种高度直观，灵活的辩论语义框架ＢＤＡＳ。     

A privacy data leakage prevention method in P2P networks

Registered peers to a P2P service can share and exchange information with other peers without servers using P2P network. In such P2P networks, there are frequent leaks of the internal privacy data of an organization through P2P file sharing. Today, DLP which is a privacy data leakage prevention technology is applied P2P network blocking and file encryption methods. However restricting all the services and normal users is difficult due to the number of ports used by P2P including the port 80. Thus, we propose a privacy data leakage prevention method by releasing a P2P sharing file that does not include privacy data using a privacy data removing technology with a privacy data leaking risk factor. The proposed method provides higher security and performance compared with a DLP method as privacy data is removed from a P2P sharing file.     

A desired landing points walking method enablinga planner quadruped robot to walk on rough terrain

It is necessary for legged robots to walk stably and smoothly on rough terrain.In this paper,a desired landing points(DLP) walking method based on preview control was proposed in which an off-line foot motion trace and an on-line modification of the trace were used to enable the robot to walk on rough terrain.The on-line modification was composed of speed modification,foot lifting-off height modification,step length modification,and identification and avoidance of unsuitable landing terrain.A planner quadruped robot simulator was used to apply the DLP walking method.The correctness of the method was proven by a series of simulations using the Adams and Simulink.     

On look-ahead heuristics in disjunctive logic programming

Disjunctive logic programming (DLP), also called answer set programming (ASP), is a convenient programming paradigm which allows for solving problems in a simple and highly declarative way. The language of DLP is very expressive and able to represent even problems of high complexity (every problem in the complexity class ${{\Sigma}_{2}^{P}} = {\rm NP}^{{\rm NP}}$ ). During the last decade, efficient systems supporting DLP have become available. Virtually all of these systems internally rely on variants of the Davis–Putnam procedure (for deciding propositional satisfiability [SAT]), combined with a suitable model checker. The heuristic for the selection of the branching literal (i.e., the criterion determining the literal to be assumed true at a given stage of the computation) dramatically affects the performance of a DLP system. While heuristics for SAT have received a fair deal of research, only little work on heuristics for DLP has been done so far. In this paper, we design, implement, optimize, and experiment with a number of heuristics for DLP. We focus on different look-ahead heuristics, also called “dynamic heuristics” (the DLP equivalent of unit propagation [UP] heuristics for SAT). These are branching rules where the heuristic value of a literal Q depends on the result of taking Q true and computing its consequences. We motivate and formally define a number of look-ahead heuristics for DLP programs. Furthermore, since look-ahead heuristics are computationally expensive, we design two techniques for optimizing the burden of their computation. We implement all the proposed heuristics and optimization techniques in DLV—the state-of-the-art implementation of disjunctive logic programming, and we carry out experiments, thoroughly comparing the heuristics and optimization techniques on a large number of instances of well-known benchmark problems. The results of these experiments are very interesting, showing that the proposed techniques significantly improve the performance of the DLV system.     

一种实现数据主动泄漏防护的扩展中国墙模型

中国墙模型具有能够同时提供自主控制和强制控制的特性,因而被广泛应用于商业领域中,以防止有竞争关系的企业之间的信息流动而导致利益冲突.但是由于对读写约束过于严格,因而应用范围有限,特别是在数据泄漏防护的应用中未能发挥其优越性.针对数据泄漏防护对信息流动的控制需求,从数据客体的角度出发,考虑中国墙模型中的利益冲突问题,提出了主动冲突关系的概念,将原来对信息双向流动的约束转换为对单向流动的约束.在此基础上,提出了一种可以实现数据主动泄漏防护的扩展中国墙模型ACWM(aggressive Chinese wall model),并给出了模型的形式化描述和相关定理的证明.分析表明,ACWM模型可以实现传统中国墙模型的安全目标,而约束条件更加灵活,可以实现数据泄漏防护的需求.     

Monadic set operations

In ordinary geonetrical modelling systems, set operations, eg union, intersection and difference, are described by dyadic operators. This kind of definition leads to a binary-tree structure.

In this paper a method is presented where only monadic set operators are used to describe the model completely. With this method the definition structure can be expressed as a list structure only.

A further feature of this model is that a special procedure to define symmetry and/or periodic repetitions of a certain shape can be easily added.

A program which uses this method has been written to test the model and some drawings produced by this program are shown in this paper.     

Content-based control of HTTPs mail for implementation of IT-convergence security environment

Convergence among industries has made network data loss prevention (DLP) more important, in that in the IT-convergence environment, web mail is utilized as a means of information delivery. The web mail used in various industries has two facets: convenience for information transfer, and vulnerability to leakage of confidential information. Monitoring blocking and logging of web mail are a few of the major security methods that have been employed for prevention of such leakage. However, application of HTTP over SSL (HTTPs) to web mail systems such as Gmail has revealed the limitations of existing web mail security methods in controlling web mail. Most importantly, the existing method cannot control encrypted contents of web mail. In this paper, we propose a method that controls HTTPs web mail contents by using a proxy server and distributing the secure socket layer (SSL) certificate to user’ s PC. The proxy server plays the Certificate Authority role between the users’ PCs and the web mail server, distributing its own SSL certificates to the users’ PCs. The SSL certificate is the key to encryption and decryption of HTTPs web mail contents. Using the protocol derived in the present study, HTTPs web mail contents can be controlled as an effect of content-awareness. Network DLP is effected by monitoring, blocking and logging suspicious mail contents using HTTPs.     

描述逻辑程序系统的设计与实现

Eiter等人为语义网提出的回答集程序和描述逻辑相结合的描述逻辑程序,获得了本体上的非单调表达和推理能力。王以松等人证明了描述逻辑程序的完备化和环公式可以精确刻画描述逻辑程序的回答集。在此基础上,进一步证明了若完备化公式的模型不是回答集则一定存在终止环公式反例,它们是多项式时间可计算的。设计并实现了借助SAT求解器MiniSAT以及描述逻辑推理机RacerPro计算描述逻辑强回答集的原型DLP_SAT。实验结果表明,该原型能有效地计算一些熟知的描述逻辑程序的强回答集。     

Semantics and complexity of recursive aggregates in answer set programming

The addition of aggregates has been one of the most relevant enhancements to the language of answer set programming (ASP). They strengthen the modelling power of ASP in terms of natural and concise problem representations. Previous semantic definitions typically agree in the case of non-recursive aggregates, but the picture is less clear for aggregates involved in recursion. Some proposals explicitly avoid recursive aggregates, most others differ, and many of them do not satisfy desirable criteria, such as minimality or coincidence with answer sets in the aggregate-free case.In this paper we define a semantics for programs with arbitrary aggregates (including monotone, antimonotone, and nonmonotone aggregates) in the full ASP language allowing also for disjunction in the head (disjunctive logic programming — DLP). This semantics is a genuine generalization of the answer set semantics for DLP, it is defined by a natural variant of the Gelfond–Lifschitz transformation, and treats aggregate and non-aggregate literals in a uniform way. This novel transformation is interesting per se also in the aggregate-free case, since it is simpler than the original transformation and does not need to differentiate between positive and negative literals. We prove that our semantics guarantees the minimality (and therefore the incomparability) of answer sets, and we demonstrate that it coincides with the standard answer set semantics on aggregate-free programs.Moreover, we carry out an in-depth study of the computational complexity of the language. The analysis pays particular attention to the impact of syntactical restrictions on programs in the form of limited use of aggregates, disjunction, and negation. While the addition of aggregates does not affect the complexity of the full DLP language, it turns out that their presence does increase the complexity of normal (i.e., non-disjunctive) ASP programs up to the second level of the polynomial hierarchy. However, we show that there are large classes of aggregates the addition of which does not cause any complexity gap even for normal programs, including the fragment allowing for arbitrary monotone, arbitrary antimonotone, and stratified (i.e., non-recursive) nonmonotone aggregates. The analysis provides some useful indications on the possibility to implement aggregates in existing reasoning engines.     

双析取逻辑程序设计基础（Ⅱ）

双析取逻辑程序设计是析取逻辑程序设计的一种扩充，其辩论语框架ＢＤＡＳ为逻辑程序设计中的常识推理提供了一种较为合理的语义框架。     

Prediction and assessment of student behaviour in open and distance education in computers using Bayesian networks

This paper presents a methodological approach based on Bayesian Networks for modelling the behaviour of the students of a bachelor course in computers in an Open University that deploys distance educational methods. It describes the structure of the model, its application for modelling the behaviour of student groups in the Informatics Course of the Hellenic Open University, as well as the advantages of the presented method under conditions of uncertainty. The application of this model resulted in promising results as regards both prediction of student behaviour, based on modelled past experience, and assessment (i.e., identification of the reasons that led students to a given ‘current' state). The method presented in this paper offers an effective way to model past experience, which can significantly aid in decision-making regarding the educational procedure. It can also be used for assessment purposes regarding a current state enabling tutors to identify mistakes or bad practices so as to avoid them in the future as well as identify successful practices that are worth repeating. The paper concludes that modelling is feasible and that the presented method is useful especially in cases of large amounts of data that are hard to draw conclusions from without any modelling. It is emphasised that the presented method does not make any predictions and assessments by itself; it is a valuable tool for modelling the educational experience of its user and exploiting the past data or data resulting from its use.     

基于直接链路协议的无线局域网络及其安全策略

无线局域网(WLAN)的直接链路协议(PLD)是WLAN服务质量(QoS)的重要组成部分。文章首先描述了WLAN的发展及在无线通信领域的重要作用;接着研究分析了WLAN网络中的新型协议———直接链路协议(DLP)的工作原理;在研究了无线局域网安全协议之后,针对DLP协议带来的安全问题,提出了基于DLP协议的安全算法及认证机制;该方法不仅保证了直接链路数据通信的安全性,同时可以减少接入点(AP)对移动主机过多管理带来的开销以及信息传输的时延。     

State estimation and multi-sensor data fusion using data-based neurofuzzy local linearisation process models

Modelling unknown non-linear dynamic processes is an essential prerequisite for model-based state estimation and fusion. Fuzzy local linearisation (FLL) is a useful divide-and-conquer method for coping with complex problems such as data-based non-linear process modelling. In this paper, a hybrid learning scheme which combines a modified adaptive spline modelling (MASMOD) algorithm and the expectation-maximisation (EM) algorithm is developed for FLL modelling, based on which Kalman filter type algorithms for state estimation and multi-sensor data fusion are investigated. Two commonly used measurement fusion methods are analytically compared. A hierarchical multi-sensor data fusion architecture is proposed, with an example of non-linear trajectory estimation to validate the proposed method, which integrates the techniques for FLL modelling, neurofuzzy state estimation and multi-sensor data fusion. Whilst this paper mainly focuses on state estimation and data fusion for unknown non-linear dynamic processes, maneuvering targets are also briefly considered.     

The Geometric Modelling of Furniture Parts and Its Application

In this paper,3-D solid modelling method appropriate for the design of furnitrue parts,which has been used in FACD(Computer Aided Design for furnitre Structure)system,is introduced,Some interactive functions for modifying part models and deriving a variety of practical parts are described.Finally,the application of the modelling method to computer aided manufactureing of furniture parts is prospected.