Semantics and verification of monitors and systems of monitors and processes

In this paper we present a sound and complete semantics for the monitor concept of C.A.R. Hoare. First a method for specification of monitors, introduced by O.-J. Dahl, is reviewed. This method is based on the relation between the historic sequence of monitor procedure calls and the historic sequence of monitor procedure exits. Based on such specifications and our new monitor semantics we present a method by which it is possible to prove that a concrete monitor is an implementation of an abstract one. In the last part of the paper an axiomatic semantics for systems of concurrent processes and monitors is introduced. The method supports verification by separation of concerns: Properties of the communication to and from each process are proven in isolation by a usual Hoare style axiomatic semantics, while abstract monitors are also specified in isolation by the method reviewed in the first part of the paper. These properties of the components of the system are then used in a new proof rule to conclude properties of the complete system. Stein Gjessing received a Ph.D. (actually a Dr. philos.) from the University of Oslo (Norway) in 1985. Presently he is an Associate Professor at the Institute of informatics, University of Oslo, Norway. Dr. Gjessings research interests are in the area of concurrent and distributed programming, operating systems, formal specification and verification and programming languages.     

SGML and XML Document Grammars and Exceptions

The Standard Generalized Markup Language (SGML) and the Extensible Markup Language (XML) allow users to define document-type definitions (DTDs), which are essentially extended context-free grammars expressed in a notation that is similar to extended Backus–Naur form. The right-hand side of a production, called a content model, is both an extended and a restricted regular expression. The semantics of content models for SGML DTDs can be modified by exceptions (XML does not allow exceptions). Inclusion exceptions allow named elements to appear anywhere within the content of a content model, and exclusion exceptions preclude named elements from appearing in the content of a content model. We give precise definitions of the semantics of exceptions, and prove that they do not increase the expressive power of SGML DTDs when we restrict DTDs according to accepted SGML practice. We prove the following results:1. Exceptions do not increase the expressive power of extended context-free grammars.2. For each DTD with exceptions, we can obtain a structurally equivalent extended context-free grammar.3. For each DTD with exceptions, we can construct a structurally equivalent DTD when we restrict the DTD to adhere to accepted SGML practice.4. Exceptions are a powerful shorthand notation—eliminating them may cause exponential growth in the size of an extended context-free grammar or of a DTD.     

The scientific method and design and test

A few years ago, during a well-attended open Design Automation Conference benchmark forum, a panellist pointed out that “...reporting experimental results is a science and an art. A survey of the literature may reveal a consistent methodology.... Also, we should address the verification of reported results.” In retrospect, the suggestion may have hinted at the vast body of techniques commonly known as experimental design. However, this forum was not ready to expand on the subject. Most search engines currently on the Web return tens of thousands of URLs in response to keyword searches using terms such as experimental design or design of experiments. Few, if any, of these search results point to an evaluation of CAD algorithms. In contrast, the experimental design methodology, pioneered by Fischer during the 1920s in agricultural research, is now firmly established in science and manufacturing. Its application to biomedical research can save lives. Biomedical journals have strict guidelines on how to report experimental results so others may replicate experiments. A URL from a medical school points to a concise illustration of a simple experimental design flow and the terminology used. Adopting the accepted norms of experimental design will give us a scientific method to conduct, verify, and report comparative performance evaluations of CAD algorithms     

Simultaneous exploration and segmentation for search and rescue

We consider the problem of active victim segmentation during a search‐and‐rescue (SAR) exploration mission. The robot is equipped with a multimodal sensor suite consisting of a camera, lidar, and pan‐tilt thermal sensor. The robot enters an unknown scene, builds a 3D model incrementally, and the proposed method simultaneously (a) segments the victims from incomplete multimodal measurements and (b) controls the motion of the thermal camera. Both of these tasks are difficult due to the lack of natural training data and the limited number of real‐world trials. In particular, we overcome the absence of training data for the segmentation task by employing a manually designed generative model, which provides a semisynthetic training data set. The limited number of real‐world trials is tackled by self‐supervised initialization and optimization‐based guiding of the motion control learning. In addition to that, we provide a quantitative evaluation of the proposed method on several real testing scenarios using the real SAR robot. Finally, we also provide a data set which will allow for further development of algorithms on the real data.     

高等院校行政分析与决策系统的设计与实现

为提高高等院校的管理水平和决策水平,充分利用校园网资 源,开发了高等院校行政财政分析与决策系统。解决了诸如数据的动态查询、自动生成报表 、网络环境下数据共享等技术问题,具有网上数据共享、图形界面友好和安全的保密措施等 特点。     

Information and Communication Technologies,Organisations and Skills: Convergence and Persistence

This article, first of all, supports the idea that the undeniable process of ICT-based technological convergence implies the social, cultural and business unification of the world of media and culture. The poor performance of the megamerger is a clear indicator of the unstable ground of the convergence hypothesis. Secondly, it argues in favour of cooperation between different expertise, skills and cultures to make multimedia products or to supply multimedia services, instead of creating from scratch a brand new class of hybrid skills and professions. Thirdly, a variety of new possible and realistically achievable professional profiles in cultural industries and institutions are illustrated. Eventually a set of public policies, in the light of a new role for cities and regions, is developed. Correspondence and offprint requests to: Francesco Garibaldo, Fondazione ‘Istituto Per il Lavoro (IPL)’, via Marconi 8, 40122 Bologna, Italy. Email: f.garibaldo@ipielle.emr.it     

Modeling and solving the steelmaking and casting scheduling problem

We propose a general model for the problem of planning and scheduling steelmaking and casting activities obtained by combining common features and constraints of the operations from a real plant and the literature. For tackling the problem, we develop a simulated annealing approach based on a solution space made of job permutations, which uses as submodule a chronological constructive procedure that assigns processing times and resources to jobs. Our technique, properly tuned in a statistically principled way, is able to find good solutions for a large range of different settings and horizons. In addition, it outperforms both a greedy procedure and a constraint‐based solver developed for comparison purposes on almost all instances. Finally, we have collected several real‐world instances that we make available on the web along with the solution validator and our best results.     

DIS和HLA系统中的记录与回放

记录和回放在军用仿真系统中有着重要的意义，该文具体分析了ＤＩＳ和ＨＬＡ系统中记录与回放的基本实现方法，并从两个方面比较了两种系统中实现上的不同点。     

Motion and shape identification with vision and range

In this paper, we consider the problem of motion and shape estimation using a camera and a laser range finder. The object considered is a plane which is undergoing a Riccati motion. The camera observes features on the moving plane perspectively. The range-finder camera is capable of obtaining the range of the plane along a given "laser plane", which can either be kept fixed or can be altered in time. Finally, we assume that the identification is carried out as soon as the visual and range data is available, or after a suitable temporal integration. In each of these various cases, we derive to what extent the motion and shape parameters are identifiable and characterize the results as an orbit of a suitable group. The paper does not emphasize any specific choice of algorithm.     

GA-fuzzy modeling and classification: complexity and performance

The use of genetic algorithms (GAs) and other evolutionary optimization methods to design fuzzy rules for systems modeling and data classification have received much attention in recent literature. Authors have focused on various aspects of these randomized techniques, and a whole scale of algorithms have been proposed. We comment on some recent work and describe a new and efficient two-step approach that leads to good results for function approximation, dynamic systems modeling and data classification problems. First, fuzzy clustering is applied to obtain a compact initial rule-based model. Then this model is optimized by a real-coded GA subjected to constraints that maintain the semantic properties of the rules. We consider four examples from the literature: a synthetic nonlinear dynamic systems model, the iris data classification problem, the wine data classification problem, and the dynamic modeling of a diesel engine turbocharger. The obtained results are compared to other recently proposed methods     

Duality and linear programs for stability and performance analysisof queuing networks and scheduling policies

We consider the problems of performance analysis and stability/instability determination of queuing networks and scheduling policies. We exhibit a strong duality relationship between the performance of a system and its stability analysis via mean drift. We obtain a variety of linear programs (LPs) to conduct such stability and performance analyses. A certain LP, called the performance LP, bounds the performance of all stationary nonidling scheduling policies. If it is bounded, then its dual, called the drift LP, has a feasible solution which is a copositive matrix. The quadratic form associated with this copositive matrix has a negative drift, showing that all stationary nonidling scheduling policies result in a geometrically converging exponential moment. These results carry over to fluid models, allowing the study of networks with nonexponential distributions. If a modification of the performance LP, called the monotone LP, is bounded, then the system is stable. Finally, there is a another modification of the performance LP, called the finite time LP. It provides transient bounds on the performance of the system from any initial condition     

Concept and design of Ad Hoc and Mobile classrooms

Abstract This investigation describes the concept of mobile learning and the design of Ad Hoc and Mobile classrooms. Four classes of mobile learning and implementation of Ad Hoc and eSchoolbag systems are presented. The paper discusses the development of advanced wireless technologies for building an ad hoc classroom to create a modern and new learning environment. As in a traditional classroom, information technology is developed to provide the teacher with aids, such as a blackboard, a board rubber, coloured chalk, a microphone, a voice recorder, a video recorder, and so on, to support teaching and discussions. Additionally, students are provided with an electronic schoolbag which contains electronic books, a notebook, a parents' contact book, a pencil case, writing materials, sheets, a calculator, an address book, and other items. Taking lessons in a lively, vivid and new learning environment, it is expected that students will improve their learning performance with perhaps less attendance in a physical classroom and they gain the flexibility of being able to learn at their own convenience.     

输变电设备运维知识图谱的构建及应用

针对电网公司在开展输变电设备运维检修过程中存在的非结构化文本数据难以利用、全口径数据难以深度融合、数据应用手段仍处于简单统计状态等难题,本文研究设计了基于知识图谱的输变电设备运维知识问答系统的总体框架,以打破传统信息获取方式的局限性。首先,从多源输变电设备数据中提取出实体、关系、属性等元素,涵盖的数据既有结构化也有非结构化的数据。在此过程中,使用不同的技术和方法来提取这些元素。其次,利用图形数据库Neo4j将这些元素组合在一起,构建一个完整的输电变电设备运维知识图谱,从而将不同类型和业务数据整合并形成一个连贯统一的知识网络。最后,基于Neo4j +Python平台搭建输变电设备运维知识问答系统,为运维人员提供一种新的方法。     

网络化立体课程建设研究与实践

阐述在教育信息化的背景下,建设立体化课程的内涵和必要性,分析了立体化课程建设的现状和建设实施步骤,并总结出建设网络立体化课程中要注意的几个关键问题,指出课程建设与专业建设、学科建设共建的趋势.     

Intersection and Union Types: Syntax and Semantics

Type assignment systems with intersection and union types are introduced. Although the subject reduction property with respect to β-reduction does not hold for a natural deduction-like system, we manage to overcome this problem in two, different ways. The first is to adopt a notion of parallel reduction, which is a refinement of Gross-Knuth reduction. The second is to introduce type theories to refine the system, among which is the theory called Π that induces an assignment system preserving β-reduction. This type assignment system further clarifies the relation with the intersection discipline through the decomposition, first, of a disjunctive type into a set of conjunctive types and, second, of a derivation in the new type assignment system into a set of derivations in the intersection type assignment system. For this system we propose three semantics and prove soundness and completeness theorems.     

Directors and IT,and IT directors

In the face of multiple challenges and opportunities, in a turbulent business environment, chief executives are seeking to create more flexible and adaptable organizations. Increasingly these are taking the form of networks, with electronic links forwards to customers, backwards to suppliers and sideways to business partners. These networks are becoming global, bringing together all those who wish to contribute a proportion of their time to a particular mission. The staff of the network organization need to be supported by a communications network that is itself flexible and adaptable, and able to facilitate multifunctional, multi-location and multi-national team working. In the main the major constraints concern people, their skills and attitudes, and the management of technology, rather than the technology itself. IT professionals, and particularly IT directors, are sought who are able to facilitate change. IT directors require directional qualities which are distinct from those demanded of managers. They need a broad, strategic awareness and perspective concerning the requirements for responsive organizations, with continuing processes for adaptation and learning to meet the changing needs of customers.     

Literacy and computer literacy: Definitions and comparisons

This paper analyzes the prevailing definitions of literacy and computer literacy. It is shown that similar factors confound our understanding of both these terms. In addition we argue that the term computer literacy is highly inappropriate. In order to clarify the meaning of these terms we suggest a hierarchy of definitions, from the operational level to the broader socio-political definitions.The paper proposes the following. Firstly a definition for the operational skills of reading and writing, for which Papert's term letteracy is used. Secondly a corresponding definition for the operational skills required to use a computer, for which the new term comperacy is proposed. Both these terms represent a continuum of skill levels and a classification for these levels is also developed. The paper concludes with an examination of the interdependencies between letteracy and comperacy which can serve as the first step in a broader analysis of the relationship between literacy and computer literacy.     

Private and oblivious set and multiset operations

Privacy-preserving set operations are a popular research topic. Despite a large body of literature, the great majority of the available solutions are two-party protocols and expect that each participant knows her input set in the clear. In this work, we put forward a new framework for secure multi-party set and multiset operations in which the inputs can be arbitrarily partitioned among the participants, knowledge of an input (multi)set is not required for any party, and the secure set operations can be composed and can also be securely outsourced to third-party computation providers. In this framework, we construct a comprehensive suite of secure protocols for set operations and their various extensions. Our protocols are secure in the information-theoretic sense and are designed to minimize the round complexity. We then also build support for multiset operations by providing (i) a generic conversion from a multiset to a set, which makes the protocols for set operations applicable to multisets and (ii) direct instantiations of multiset operations of improved performance. All of our protocols have communication and computation complexity of \(O(m \log m)\) and logarithmic round complexity for sets or multisets of size m, which compares favorably with prior work. Practicality of our solutions is shown through experimental results, and novel optimizations based on set compaction allow us to improve performance of our protocols in practice. Our protocols are secure in both semi-honest and malicious security models.     

802.1x协议的认证计费系统设计与实现及缺陷改进

本文针对日益扩大的网络规模及网络管理存在着许多难题,设计实现了基于802.1x的认证计费管理系统,并对其缺陷进行了改进。解决了校园网用户接入身份认证,授权,计费等网络应用中的核心问题;并实现了按月、按时长、按流量多种灵活的计费策略。     

面向模式分析与设计方法应用研究

随着软件系统复杂程度的增加,一个完整的系统已不能由一个单独的模式建立起来,它将是多个模式的组合。面向模式的分析与设计关注于模式作为类的合成体的组合技术,将模式作为设计单元,通过对模式的合成和精练来优化程序设计,有利于快速的开发出更具有可扩展性和可维护性的软件系统。