Optimizing a multiserver queuing system with a variable number of servers

A multiserver Poisson queuing system with losses, with a variable number of servers, and an additive quality functional is investigated. All major characteristic of the system are obtained in an explicit form. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 4, pp. 92–101, July–August 2007.     

On a multiserver markovian queueing system with balking and reneging

In this paper a multi-server queueing model with balking and reneging is considered. Steady-state distribution of the number of customers in the system is obtained. An expression for the average loss of customers during a fixed duration of time is also advanced.     

One multiserver mixed queueing system with the limited waiting time

In this paper, a M/G/n/c multiserver queueing system with basic and standby servers is studied. Customers servicing is disturbed by failures of servers that make up a simplest flow. After the failure, the server needs a random time for renewal. It is also assumed that customers have limited, exponentially distributed waiting time in the system. The system is studied in both stationary and nonstationary modes.     

信元调度问题中有优先级的多服务台排队系统

根据排队理论对带有优先级的多服务台信元调度问题进行了定量分析,推导出了每个级别的信元平均时延及丢包率的计算公式,并进行了计算机仿真。根据理论分析和仿真结果,得出了在缓冲区既定的情况下,可以采用提高服务率或者是增加服务台数来有效的降低平均时延和丢包率的结论。由已经得到的公式,可以确定将平均时延及丢包率控制在所允许的范围的服务率和服务台数。     

Enhancing and protecting quantum correlations of a two-qubit entangled system via non-Hermitian operation

We investigate the dynamics of geometric measure of quantum discord and negativity as a measure of quantum entanglement for the system under the local non-Hermitian operation. Numerical calculations demonstrate that quantum discord and entanglement as two kinds of typical measures of quantum correlations can exceed respective initial value, and their evolution behaviors appear to violate conventional properties which formulates quantum discord and quantum entanglement are invariants under local operations. Our results show that non-Hermitian operation achieves distinctive effects on enhancement and protection of quantum correlations, which is mostly aroused by the non-Hermiticity and the non-unitarity of the non-Hermitian operation.     

Enhancing information security with the information resource management approach

Recently, computer security and incidents of computer crime have received considerable attention. Without a doubt, in computer security the risks are high, and the problems and their solutions are complex; nonetheless, the emphasis of this attention has been misplaced. The emphasis should be primarily on the security of information itself and secondarily on the devices that handle information and on any of the other factors that go into information production. The factors of information production should certainly be considered, but only after planning and analysis based on information has been completed. For example, when considering the possibility that a competitor may steal your firm's proprietary information, it is best to consider first what information should be safequarded and what expenditure is warranted for such protection; then one can consider the environments in which this information appears (paper-based, computerized, verbal, etc.) and controls that are appropriate for these environments.This paper explores the application to the information security area of Information Resource Management (IRM), a new and promising approach that concentrates, on information not on computers. This paper explains the concepts underlying IRM, how they are applied, and what general information systems benefits can be obtained. In a more specifically security-oriented sense, it indicates how IRM can help address a few of the pressing problems now encountered by information security practitioners: controls suboptimization, the Maginot Line syndrome, top management understanding and support, disaster recovery planning, security policy-making, consideration of noncomputerized information, and expeditious resolution of security problems.     

CSMA/CD with reservations in wireless communication for distributed robot system

This paper proposes a medium access protocol, CSMA/CD-R (Carrier Sense Multiple Access/Collision Detection with Reservation), designed for a distributed robot system based on wireless network without any centralized mechanism. It employs stations to reserve a communication channel after communication collision such that it shows better performance than conventional CSMA protocol for the wireless communication of the distributed robot system. The effectiveness and applicability of the proposed protocol are demonstrated by carrying out both computer simulations and real experiments with the developed multi-robot system.     

Post-release information privacy protection: A framework and next-generation privacy-enhanced operating system

In today’s digital world, privacy issues have received widespread public attention. Current research on information privacy protection focuses on release control and subject identity obscurity. Little work has been done, however, to prevent a piece of private information from being misused after that information has been released to external entities. This paper focuses on information privacy protection in a post-release phase. Without entirely depending on the information collector, an information owner is provided with powerful means to control and audit how his/her released information will be used, by whom, and when. The goal is to minimize the asymmetry of information flow between an information owner and an information collector. A set of innovative owner-controlled privacy protection and violation detection techniques has been proposed: Self-destroying File, Mutation Engine System, Automatic Receipt Collection, and Honey Token-based Privacy Violation Detection. Next generation privacy-enhanced operating system, which supports the proposed mechanisms, is introduced. Such a privacy-enhanced operating system stands for a technical breakthrough, which offers new features to existing operating systems. We discuss the functionalities of such an operating system and the design guidelines. To our best knowledge, no similar technical work has been found to provide post-release information privacy protection.     

Solving efficiently Decentralized MDPs with temporal and resource constraints

Optimizing the operation of cooperative multi-agent systems that can deal with large and realistic problems has become an important focal area of research in the multi-agent community. In this paper, we first present a new model, the OC-DEC-MDP (Opportunity Cost Decentralized Markov Decision Process), that allows us to represent large multi-agent decision problems with temporal and precedence constraints. Then, we propose polynomial algorithms to efficiently solve problems formalized by OC-DEC-MDPs. The problems we deal with consist of a set of agents that have to execute a set of tasks in a cooperative way. The agents cannot communicate during task execution and they must respect resource and temporal constraints. Our approach is based on Decentralized Markov Decision Processes (DEC-MDPs) and uses the concept of opportunity cost borrowed from economics to obtain approximate control policies. Experimental results show that our approach produces good quality solutions for complex problems which are out of reach of existing approaches.     

Systematically testing a real-time operating system

Testing large and complex software is an inherently difficult process that must be as systematic as possible to provide adequate reliability and quality assurance. This is particularly true for a complex real-time operating system in which an ad hoc testing approach would certainly fail to affirm the quality and correctness of the requirements specification, design, and implementation. We discuss applying systematic strategies to the testing of real-time operating system RTOS under development in the Esprit III project 8906 OMI/CLEAR     

Porting a new microcomputer operating system

On April 29th 1983 Tycom Corporation announced that it was the first company in the UK to have brought the MSDOS 2.0 operating system up and running on its microcomputer. The rudiments of the porting process are outlined. Two specific features are described in detail. They are new form of the Bios in MSDOS 2.0 and Tycom's innovative procedure which allows more than one operating system to reside on a disc at a time.     

Synchronization under a commercial operating system

Mutual exclusion and general synchronization of concurrent processes (‘tasks’) are well-known principles for constructing reliable real-time systems. This paper shows how to implement these principles under a typical commercial operating system which provides incomplete synchronization operations. The problem of synchronizing erroneous tasks is discussed briefly.     

An intelligent agent with layered architecture for operating systems resource management

Abstract: A software agent is defined as an autonomous software entity that is able to interact with its environment. Such an agent is able to respond to other agents and/or its environment to some degree, and has some sort of control over its internal state and actions. In belief–desire–intention (BDI) theory, an agent's behavior is described in terms of a processing cycle. In this paper, based on BDI theory, the processing cycle is studied with a software feedback mechanism. A software feedback or loop‐back control mechanism can perform functions without direct external intervention. A feedback mechanism can continuously monitor the output of the system under control (the target system), compare the result against preset values (goals of the feedback control) and feed the difference back to adjust the behavior of the target system in a processing cycle. We discuss the modeling and design aspects of an autonomous, adaptive monitoring agent with layered control architecture. The architecture consists of three layers: a scheduling layer, an optimizing layer and a regulating layer. Experimental results show that the monitoring agent developed for an e‐mail server is effective.     

基于Linux操作系统的安全编程

Linux操作系统对多任务、多用户和网络服务的支持使得Linux的管理和开发人员需要更多地关注安全问题,以避免数据的泄漏和丢失以及应用系统遭受破坏。介绍了ISO安全模型,以及在Linux编程中如何使用系统提供的认证和访问控制服务和如何避免几种最常见的安全性错误。     

Interfacing the hardware API with a feature-based operating system family

Multiprocessor systems on a chip (MPSoCs) are a popular class of course-grained parallel computer architectures, which are very useful, because they support re-use of legacy software components and application-specific tailoring of hardware structures at the same time. Furthermore, model-driven design frameworks for MPSoCs such as Xilinx’ EDK or our own LavA-framework facilitate very fast system development. However, in this paper we argue that these design frameworks are not ideal from the development process perspective. Instead, we propose a software-centric approach that is based on the hardware API concept. The API is a representation of hardware components on the software level, which is generated from a hardware meta-model. It allows us to automatically derive a hardware structure based on access patterns in software, revealed by a static code analysis. This trick reduces the number of hardware details the developer needs to deal with and avoids configuration inconsistencies between the hardware and software levels by design. Furthermore, we present how the development process can benefit from the hardware API, when the API is interfaced with a configurable operating system.     

Enhancing digital reading performance with a collaborative reading annotation system

As children now spend considerable time reading electronic media, digital reading skills and good reading comprehension are essential. However, many studies agree that screen-based reading leads to shallow reading, short attention spans, and poor comprehension. Therefore, this work presents a collaborative reading annotation system with a reading annotation and interactive discussion scaffold (CRAS-RAIDS) for improving reading performance in collaborative digital reading environments. This study used a quasi-experimental design. Fifty-three Grade 5 students were recruited from two classes of an elementary school in Taoyuan County, Taiwan. One class was randomly designated the experimental group used the proposed CRAS-RAIDS support for collaborative reading. The other class was designated the control group and used the traditional paper-based reading annotation method and face-to-face discussions. The two groups were then compared in terms of reading attitude, reading comprehension, and use of reading strategy in an active reading context. Analytical results show that the experimental group significantly outperformed the control group in direct and explicit comprehension, inferential comprehension performance, and use of reading strategy. Moreover, the experimental group, but not the control group, had a significantly improved reading attitude in the total dimensions and in the behavioral and affective sub-dimensions. Additionally, the experimental group showed positive interest and high learning satisfaction.     

PGSW-OS: a novel approach for resource management in a semantic web operating system based on a P2P grid architecture

A web operating system is an operating system that users can access from any hardware at any location. A peer-to-peer (P2P) grid uses P2P communication for resource management and communication between nodes in a grid and manages resources locally in each cluster, and this provides a proper architecture for a web operating system. Use of semantic technology in web operating systems is an emerging field that improves the management and discovery of resources and services. In this paper, we propose PGSW-OS (P2P grid semantic Web OS), a model based on a P2P grid architecture and semantic technology to improve resource management in a web operating system through resource discovery with the aid of semantic features. Our approach integrates distributed hash tables (DHTs) and semantic overlay networks to enable semantic-based resource management by advertising resources in the DHT based upon their annotations to enable semantic-based resource matchmaking. Our model includes ontologies and virtual organizations. Our technique decreases the computational complexity of searching in a web operating system environment. We perform a simulation study using the Gridsim simulator, and our experiments show that our model provides enhanced utilization of resources, better search expressiveness, scalability, and precision.     

MUSS—a portable operating system

This paper describes a technique for producing a machine-independent operating system with a high level of performance. The technique is based on the definition of a hypothetical ideal machine, which acts as the target computer for the operating system. The characteristics of this ideal machine are described in detail.     

Ergodic distribution of a system resource

The Laplace transform of the ergodic distribution of a semi-Markov random-walk process with a delay screen at zero is found.Translated from Kibernetika i Sistemnyi Analiz, No. 5, pp. 183–187, September–October 2004.