《建造合同》准则执行中的若干问题的思考

我国在1998年6月第一次发布了《建造合同》准则,2006年2月重新修订并发布了新的《建造合同》准则,新准则要求会计人员具有较高的业务素质和职业判断能力,并要求提高实务操作能力。文章结合江汉油建公司现行核算办法,分析了建造合同新的核算办法与江汉油建公司目前核算上存在的差异,并在此基础上提出了相应的解决措施。     

磁带库虚拟化存储系统的设计与实现

信息技术的发展和互联网的不断普及和发展,人们的数据安全意识逐渐增强,大容量的磁带库设备以及共享的逻辑存储设备,使海量数据存储备实现了完善的存储。通过对数据存储问题分析,明确了磁带库虚拟化存储系统的设计要求和方向,并以磁带库虚拟化存储系统的具体设计,明确了磁带库虚拟化储存体系的具体结构和层次。     

构建项目课程模式下的新教学评价体系

评价体系的改革是项目课程体系改革的重要一环,在给出传统教学评价体系基础上,构建新教学评价体系,并以具体的工作任务为例说明新教学评价的实施,实践证明,新教学评价体系能激发学生学习的积极性,主动性,有利于培养学生的综合职业能力,缩短学校与社会接轨的时间。     

Project preparedness and the emergence of implementation problems in ERP projects

The problems that organizations face in implementing an enterprise-wide ERP project are linked to their level of understanding of what is involved in such an endeavor and how it influences their initial preparations. We sought to demonstrate empirically the causal relationship between the organization's preparedness and the emergence of implementation problems. We examined four case studies to extract insight into the criticality of certain factors and the type of problems created when no moderating measures were taken by project managers. Consequently, we developed a predictor-outcome model mapping a lack of preparedness with implementation problems.     

The design and implementation of a session layer for delay-tolerant networks

The DTN architecture is based around sender-initiated unicast communication that is insufficient or inconvenient to meet the needs of many applications. To address these limitations, we define a DTN session layer and associated extensions to the DTN bundle protocol that more naturally support receiver-driven applications and multicast communication. Within a session, we provide mechanisms allowing applications to convey ordering relationships between successive transmissions that can be used by the network to help ensure a distributed application’s delivery ordering expectations are met. We also extend the bundle protocol’s expiration procedures to support more efficient network utilization by allowing in-network deletion of obsolete messages. We present the design rationale and describe our implementation of these mechanisms and discuss their advantages in meeting the needs of several popular types of applications.     

The Shadow Knows: Refinement and security in sequential programs

Stepwise refinement is a crucial conceptual tool for system development, encouraging program construction via a number of separate correctness-preserving stages which ideally can be understood in isolation. A crucial conceptual component of security is an adversary’s ignorance of concealed information. We suggest a novel method of combining these two ideas.Our suggestion is based on a mathematical definition of “ignorance-preserving” refinement that extends classical refinement by limiting an adversary’s access to concealed information: moving from specification to implementation should never increase that access. The novelty is the way we achieve this in the context of sequential programs.Specifically we give an operational model (and detailed justification for it), a basic sequential programming language and its operational semantics in that model, a “logic of ignorance” interpreted over the same model, then a program-logical semantics bringing those together — and finally we use the logic to establish, via refinement, the correctness of a real (though small) protocol: Rivest’s Oblivious Transfer. A previous report^? treated Chaum’s Dining Cryptographers similarly.In passing we solve the Refinement Paradox for sequential programs.     

Individual characteristics and the intention to continue project escalation

The factors leading to the continuing problems with information system (IS) project failure are of importance to both the research and practitioner communities. The psychological factors that lead project managers to escalate troubled projects are investigated. Theoretical grounding is presented for a research model consisting of Need for Achievement as an antecedent trait for implementation mindset, internal locus of control, preference for consistency, and time urgency, which in turn predict the Intention to Continue a troubled IS project. Using responses from 232 IS project stakeholders, the model is tested using structural equation modeling. The results support Need for Achievement as an antecedent to the other independent variables. Implementation mindset and internal locus of control were found to be significant predictors of the project managers’ intention to continue the IS projects. Based on the findings, suggestions for project re-evaluation milestones (PRMs) are presented.     

Fixed-point DSP implementation of nonlinear controller for large gap electromagnetic suspension system

Electromagnetic suspension systems are inherently nonlinear and often face hardware limitation when digitally controlled. The main contributions of this paper are: the design of a nonlinear H_∞ controller, including dynamic weighting functions, applied to a large gap electromagnetic suspension system and the presentation of a procedure to implement this controller on a fixed-point DSP, through a methodology able to translate a floating-point algorithm into a fixed-point algorithm by using l_∞ norm minimization due to conversion error. Experimental results are also presented, in which the performance of the nonlinear controller is evaluated specifically in the initial suspension phase.     

RFuzzy: Syntax, semantics and implementation details of a simple and expressive fuzzy tool over Prolog

We present the RFuzzy framework, a Prolog-based tool for representing and reasoning with fuzzy information. The advantages of our framework in comparison to previous tools along this line of research are its easy, user-friendly syntax, and its expressivity through the availability of default values and types.In this approach we describe the formal syntax, the operational semantics and the declarative semantics of RFuzzy (based on a lattice). A least model semantics, a least fixpoint semantics and an operational semantics are introduced and their equivalence is proven. We provide a real implementation that is free and available. (It can be downloaded from http://babel.ls.fi.upm.es/software/rfuzzy/.) Besides implementation details, we also discuss some actual applications using RFuzzy.     

两种工作电源的设计与实现

给出了直流稳压电源和逆变电源的设计方案。直流稳压电源具有两路±1 5 V,两路±1 2 V,两路±5 V和一路1.25～37V连续可调七路输出,每路输出电流最大可达1.5A;逆变电源输出功率可达250VA。经测试,这两种电源输出精确,稳定性好,是一种理想的实验室或家用电源。