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1.
Programmable rewriting strategies provide a valuable tool for implementing traversal functionality in grammar-driven (or schema-driven) tools. The working Haskell programmer has access to programmable rewriting strategies via two similar options: (i) the Strafunski bundle for generic functional programming and language processing, and (ii) the “Scrap Your Boilerplate” approach to generic functional programming. Basic rewrite steps are encoded as monomorphic functions on datatypes. Rewriting strategies are polymorphic functions composed from appropriate basic strategy combinators.We will briefly review programmable rewriting strategies in Haskell. We will address the following questions:
• What are the merits of Haskellish strategies?
• What is the relation between strategic programming and generic programming?
• What are the challenges for future work on functional strategies?
Keywords: Rewrite startegies; programming languages; Haskell; functional programming  相似文献   

2.
在模型驱动开发的场景下,保证UML模型的一致性具有重要意义,但目前大多数UML/MDA工具仪提供了有限支持。该文提出了一种基于代数重写逻辑的UML模型一致性检查的方法。首先定义了基于两级代数规范的实施构架以分别检查UML模型的没讣时和运行时语义一致性,其次定义了检查包括类图、状态机图和顺序图在内的多图一致性的重写规则。该方法为保持面向可执行的UML模型的一致性提供了有效支持。  相似文献   

3.
MFS是一个基于重写技术的程序开发系统.它提供的程序设计语言MFSL是扩展的函数式语言与代数规约语言相结合的混合语言.在这种混合语言中引入了能够提高效率和满足用户特殊需求的优化规则定义机制.语言的类型系统以及在语言和系统中引入的证明和测试机制能够使人们在开发过程中较早地发现问题,提高所开发系统的正确性.在系统的实现中采用的必要平行最外归约策略、图归约、证据测试集等技术能够使所开发的系统具有很高的实现效率.应用这一程序开发系统,能够较快地开发出正确且效率较高的程序.  相似文献   

4.
Neng‐Fa Zhou 《Software》2003,33(13):1199-1216
CGLIB is a high‐level graphics library for B‐Prolog, a constraint logic programming system. The library provides primitives for creating and manipulating graphical objects and a set of constraints including not‐overlap, grid, table and tree constraints that facilitate the specification of the layouts of objects. The library adopts a construct called action rules which is available in B‐Prolog for creating agents and programming interactions among agents or between agents and the user. The library is a fully working system implemented in B‐Prolog, Java and C. It can be used in many areas such as drawing editors, interactive user interfaces, document authoring, animation, information visualization, intelligent agents and games. The high‐level abstraction of the library and the use of constraints and action rules in the specification of layouts and behaviors can significantly enhance the productivity of the development of graphics. We demonstrate through several examples the effectiveness of the library as a tool for developing graphics‐rich and interactive user interfaces. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

5.
为了增强用户身份认证机制的安全性,在传统的口令认证方式的基础上,提出了一种基于模糊逻辑的击键特征用户认证方法。该方法利用模糊逻辑对用户输入口令的键盘特征进行分析鉴别,并结合用户口令进行用户身份认证。该方法有效弥补了传统的口令机制易被攻击的缺点,有一定的实用性。  相似文献   

6.
The need to provide effective tools for analyzing and querying spatial data is becoming increasingly important with the explosion of data in applications such as geographic information systems, image databases, CAD, and remote sensing. The SEE (Spatial Exploration Environment) is the first effort at applying direct-manipulation visual information seeking (VIS) techniques to spatial data analysis by visually querying as well as browsing spatial data and reviewing the visual results for trend analysis. The SEE system incorporates a visual query language (SVIQUEL) that allows users to specify the relative spatial position (both topology and direction) between objects using direct manipulation. The quantitative SVIQVEL sliders (S-sliders) are complemented by the qualitative active-picture-for-querying (APIQ) interface that allows the user to specify qualitative relative position queries. APIQ provides qualitative visual representations of the quantitative query specified by the S-sliders. This increases the utility of the system for spatial browsing and spatial trend discovery with no particular query in mind. The SVIQUEL queries are processed using a k-Bucket index structure specifically tuned for incremental processing of the multidimensional range queries that represent the class of queries that can be expressed by SVIQUEL. We have also designed a tightly integrated map visualization that helps to preserve the spatial context and a bar visualization that provides a qualitative abstraction of aggregates  相似文献   

7.
8.
This study examines the automatization of irrigation tasks of solar photovoltaic water pumping systems (SPVWPS) in greenhouse applications. A prototype of an embedded control system has been developed for SPVWPS battery‐coupled architectures. The new design aims at improving the safety of solar irrigation facility by avoiding the exhaustion of pumping resources (water and energy) while watering. The availabilities of pumping resources are introduced as new requisite inputs of a fuzzy logic‐based control system (FLC) so that it can produce adequate and safe irrigation durations. The FLC design consists of two cascaded devices. The first device uses climate data to estimate durations for watering that satisfy crop needs. The second device uses actual resource levels to evaluate the pumping capacity of the SPVWPS regarding requested durations. Watering is performed whenever the pumping capacity of the system represents more than 25% of the total requirement. Test results from an experimental greenhouse prove the effectiveness of the decision‐making mechanism that prevents scheduling unsuccessful watering tasks.  相似文献   

9.
Grammar deployment is the process of turning a given grammar specification into a working parser. The Grammar Deployment Kit (for short, GDK) provides tool support in this process based on grammar engineering methods. We are mainly interested in the deployment of grammars for software renovation tools, that is, tools for software re- and reverse engineering. The current version of GDK is optimized for Cobol. We assume that grammar deployment starts from an initial grammar specification which is maybe still ambiguous or even incomplete. In practice, grammar deployment binds unaffordable human resources because of the unavailability of suitable grammar specifications, the diversity of parsing technology as well as the limitations of the technology, integration problems regarding the development of software renovation functionality, and the lack of tools and adherence to firm methods for grammar engineering. GDK helps to largely automate grammar deployment because tool support for grammar adaptation and parser generation is provided. We support different parsing technologies, among them btyacc, that is, yacc with backtracking. GDK is free software.  相似文献   

10.
11.
Federal information systems initially developed from isolated islands of computing. Through progressive changes, these individual systems became connected by common users and common information needs. These systems are now well on the way to migrating toward computing environments that consist of distributed, heterogeneous, networked applications, databases, and hardware. The concept of a Federal computing environment that is built on an infrastructure defined by open, consensus-based standards is well on its way to becoming a de facto means of organizing these systems. Such an infrastructure is called an Open System Environment (OSE).

An Open System Environment encompasses the functionality needed to provide interoperability, portability, and scalability of computerized applications across networks of heterogeneous, multi-vendor hardware/software/communications platforms. The OSE forms an extensible framework that allows services, interfaces, protocols, and supporting data formats to be defined in terms of nonproprietary specifications that evolve through open (public), consensus-based forums.

A selected suite of specifications that defines the interfaces, services, protocols, and data formats for a particular class or domain of applications is called a profile. The Application Portability Profile (APP) integrates industry.  相似文献   


12.
基于Struts+Hibernate+Spring框架的劳资管理系统研究   总被引:1,自引:0,他引:1  
利用Struts、Hibernate和Spring,这三种架构设计一套B/S架构的劳资管理系统。该系统分为三层,在J2EE平台下整合三种技术,使系统层次划分更为清晰,可扩展性大大增强,大幅度提高了软件开发的效率。  相似文献   

13.
A normal synchronous time multiplexed system has low capacity utilisation of a trunk channel, owing to the ON-OFF nature of speech in human conversation. A time assignment speech interpolation (TASI) system nearly doubles this efficiency, at relatively small increase in hardware cost. In TASI, during the silent period of speech, the channel is allotted to some other ‘active’ subscriber on a first-come-first-serve basis. A microprocessor based system offers a very cost effective solution from hardware count. Intel 8085 A has been selected for the purpose. The microprocessor functions in a distributed processing mode together with the main CPU controlling the stored program exchange. The system uses digital dynamic speech detectors for detecting transitions in speech over a channel, as they show considerably superior performance over amplitude detectors. An assembly language program for the system has been developed.  相似文献   

14.
Garrocq  C.A. Hurley  M.J. 《Computer》1975,8(4):23-33
The design of a new aerospace vehicle is a complex, long-term process. At the onset, a set of objectives is identified in the areas of mission, weight, performance, payload, etc., which are specified with a fairly good knowledge of the available design technology and constraints. The designer possesses a fund of accumulated experience and knowledge that he applies, with imagination and intuition, to meet the requirements and constraints he has been given. The knowledge and experience of the designer are more and more frequently being delegated to the computer; intuition and imagination can never be. In spite of the extensive use of computers in portions of the design process, total turnaround times are long; drudgery interrupts and stalls the engineer. The total project data is segmented and scattered throughout the design team to such an extend that accessing, coordinating, and updating become difficult and complex. The team gets the job done, but only after painfully tedious effort.  相似文献   

15.
本文通过对FSSS系统问题引起的机组异常事件的分析,说明完善FSSS系统的重要性,结合台州发电厂DCS改造项目中的FSSS系统设计方案为实例,提出了通过电源冗余设计以及软件冗余设计等优化FSSS系统的方式和方法;来达到为机组可靠运行提供保证的有力措施。  相似文献   

16.
17.
Abstract— With the maturation of three‐dimensional (3‐D) technologies, display systems can provide higher visual quality to enrich the viewer experience. However, the depth information required for 3‐D displays is not available in conventional 2‐D recorded contents. Therefore, the conversion of existing 2‐D video to 3‐D video becomes an important issue for emerging 3‐D applications. This paper presents a system which automatically converts 2‐D videos to 3‐D format. The proposed system combines three major depth cues: the depth from motion, the scene depth from geometrical perspective, and the fine‐granularity depth from the relative position. The proposed system uses a block‐based method incorporating a joint bilateral filter to efficiently generate visually comfortable depth maps and to diminish the blocky artifacts. By means of the generated depth map, 2‐D videos can be readily converted into 3‐D format. Moreover, for conventional 2‐D displays, a 2‐D image/video depth perception enhancement application is also presented. With the depth‐aware adjustment of color saturation, contrast, and edge, the stereo effect of the 2‐D content can be enhanced. A user study on subjective quality shows that the proposed method has promising results on depth quality and visual comfort.  相似文献   

18.
Just-in-time and just-in-sequence (JIS) concepts have been presented by the automotive industries in the past years. Today, where customer-oriented manufacturing is more and more demanded, electronics production is in a similar situation. The integral organizational means at Diehl AKO Nuremberg have been realized to achieve JIS material supply in the electronics sector. The right cooperation of software solutions from SAP (ERP), LES (logistics) to BOFOS (manufacturing planning) results in a set of improvements in material flow, scheduling, and document flow. The following paper shows the concepts, realizations, and achievements of the partners Diehl AKO and ETL. The main interest lies on the general approach, not on a particular detail.  相似文献   

19.
The Asf+Sdf Meta-Environment is an interactive development environment for the automatic generation of interactive systems for constructing language definitions and generating tools for them. Over the years, this system has been used in a variety of academic and commercial projects ranging from formal program manipulation to conversion of COBOL systems. Since the existing implementation of the Meta-Environment started exhibiting more and more characteristics of a legacy system, we decided to build a completely new, component-based, version. We demonstrate this new system and stress its open architecture.  相似文献   

20.
本文设计了一套采用GPRS技术的动力环境监控系统,具有告警管理、四遥信息、配置管理、统计管理和系统维护等功能。系统利用成熟的.Net架构,借助移动的GPRS传输通道,采用B/S模型和C/S模型相结合的方式,系统完全基于浏览器运行,方便系统部署。特别针对通信网络不健全的监控场地,对其进行动力与环境的监控具有现实意义。  相似文献   

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