NSEDIT: A syntax-directed editor and testing tool based on Nassi—Shneiderman charts

This paper describes a programming environment for Pascal, called NSEDIT, which runs under VAX/VMS

1 VAX/VMS is a trademark of the Digital Equipment Corporation.

. NSEDIT is based upon the notion of Nassi-Shneiderman charts (abbreviated to N-S charts in this paper) and is designed for ease of use by novice programmers in a teaching situation. A key component of the system is the editor, which enables structural features of Pascal to be manipulated in terms of their N-S chart box representations. Simultaneous editing of more than one program or module is permitted. Another key feature of the system is a semiautomatic interface to the VAX/VMS Pascal compiler, with subsequent display of execution counts as part of the N-S charts. In this way users can obtain immediate feedback on the coverage of program elements by test runs, while still inside an editing session.     

An object-oriented approach to application generation

The TUBA system consists of a set of integrated tools for the generation of business-oriented applications. Tools and applications have a modular structure, represented by class objects. The article describes the architecture of the environments for file processing, screen handling and report writing.     

Specification methodology: An integrated relational approach

The effectiveness of set theoretic concepts for the purpose of software specification is becoming more and more widely recognized. This paper presents an integrated relational methodology for software specification, and shows its effectivness when applied to a practical example.     

A local approach to concept generation

Generating concepts defined by a binary relation between a set of properties and a set of objects is one of the important current problems encountered in Data Mining and Knowledge Discovery in Databases. We present a new algorithmic process which computes all the concepts, without requiring an exponential-size data structure, and with a good worst-time complexity analysis, which makes it competitive with the best existing algorithms for this problem. Our algorithm can be used to compute the edges of the lattice as well at no extra cost.      

A geometric approach to boundary-conformed toolpath generation

Isoparametric or streamline-like toolpath generation is an important method for CNC surface machining. For a trimmed surface, the generation of such a toolpath is not straightforward because by simply following the isoparametric curves of the parametric surface to generate the toolpath, the resulting toolpath may no longer conform to the trimmed boundary of the surface. Various methods have been proposed to solve this problem. Some methods work well for single surface machining, but may not be feasible for multi-patch surface machining. A new geometric approach to the problem of multi-patch machining is proposed in this paper. The new method works by generating bisectors to partition the region into smaller subregions, and generates the toolpath by offsetting the subregion boundary by using a special offset function. As this new method does not rely on processing on the parametric domain of the surface patches, it can be used for both NURBS and subdivision surfaces. Examples are given to demonstrate the capability of the new method, and to show that the new method compares favorably with existing techniques.     

CHEF: A versatile portable text editor

CHEF is an interactive text editor for use with both printing and display terminals. Its prime field of application is computer source program editing but it has some word processing capabilities that make it useful for documentation and general text editing work. There is a comprehensive set of whole-line operations, including block moves and the insertion of text from external files, together with substring replacement and line segmentation based on a flexible pattern-matching algorithm. There is a set of one-line buffers for temporary storage of lines or command strings and complex command sequences can be built up by macro substitution. Considerable effort has been made to design a command syntax that is flexible and consistent and, at the same time, minimizes effort during the editing process. CHEF copies the user's file into an internal work-space so that the original is not disturbed until the user is satisfied with the results of the editing session. A virtual memory technique is used to provide a work-space that can be almost any desired size, with random access to any part and efficient editing operations. CHEF is written in BCPL and has already been implemented on four different machines.     

Anisotropic quadrilateral mesh generation: An indirect approach

In this paper a new indirect approach is presented for anisotropic quadrilateral mesh generation based on discrete surfaces. The ability to generate grids automatically had a pervasive influence on many application areas in particularly in the field of Computational Fluid Dynamics. In spite of considerable advances in automatic grid generation there is still potential for better performance and higher element quality. The aim is to generate meshes with less elements which fit some anisotropy criterion to satisfy numerical accuracy while reducing processing times remarkably. The generation of high quality volume meshes using an advancing front algorithm relies heavily on a well designed surface mesh. For this reason this paper presents a new technique for the generation of high quality surface meshes containing a significantly reduced number of elements. This is achieved by creating quadrilateral meshes that include anisotropic elements along a source of anisotropy.     

An energy planning approach based on mixed 0–1 Multiple Objective Linear Programming

Multiple Objective Linear Programming (MOLP) models have been widely used in the energy sector for taking into account several conflicting objectives pursued in energy planning. However, continuous variables are not suffcient to accurately represent discrete phenomena encountered in many practical decision situations, such as the power generation expansion problem. This paper presents a new approach based on a mixed 0–1 MOLP model and applied to the Greek electricity generation sector for identifying the number and output of each type of power units needed to satisfy the expected electricity demand in the future. The core of the model is a branch and bound algorithm, which has been properly modified for the multi-objective case and is capable of generating the whole set of effcient solutions. The results provided by this method is the extraction of the effcient combinations of the power generation units, and for each combination the effcient solutions determining electricity production from each unit.     

A semi-direct approach to structure from motion

The problem of structure from motion is often decomposed into two steps: feature correspondence and three-dimensional reconstruction. This separation often causes gross errors when establishing correspondence fails. Therefore, we advocate the necessity to integrate visual information not only in time (i.e. across different views), but also in space, by matching regions – rather than points – using explicit photometric deformation models. We present an algorithm that integrates image-feature tracking and three-dimensional motion estimation into a closed loop, while detecting and rejecting outlier regions that do not fit the model. Due to occlusions and the causal nature of our algorithm, a drift in the estimates accumulates over time. We describe a method to perform global registration of local estimates of motion and structure by matching the appearance of feature regions stored over long time periods. We use image intensities to construct a score function that takes into account changes in brightness and contrast. Our algorithm is recursive and suitable for real-time implementation.     

An architectural approach to improved program maintainability

A programming standard is described, with the emphasis on the visual aspects of the final product rather than on how the programs are engineered.     

A constraint programming based column generation approach to nurse rostering problems

This paper presents our investigations on a hybrid constraint programming based column generation (CP–CG) approach to nurse rostering problems. We present a complete model to formulate all the complex real-world constraints in several benchmark nurse rostering problems. The hybrid CP–CG approach is featured with not only the effective relaxation and optimality reasoning of linear programming but also the powerful expressiveness of constraint programming in modeling the complex logical constraints in nurse rostering problems. In solving the CP pricing subproblem, we propose two strategies to generate promising columns which contribute to the efficiency of the CG procedure. A Depth Bounded Discrepancy Search is employed to obtain diverse columns. A cost threshold is adaptively tightened based on the information collected during the search to generate columns of good quality. Computational experiments on a set of benchmark nurse rostering problems demonstrate a faster convergence by the two strategies and justify the effectiveness and efficiency of the hybrid CP–CG approach.     

A column generation approach to the heterogeneous fleet vehicle routing problem

We consider a vehicle routing problem with a heterogeneous fleet of vehicles having various capacities, fixed costs and variable costs. An approach based on column generation (CG) is applied for its solution, hitherto successful only in the vehicle routing problem with time windows. A tight integer programming model is presented, the linear programming relaxation of which is solved by the CG technique. A couple of dynamic programming schemes developed for the classical vehicle routing problem are emulated with some modifications to efficiently generate feasible columns. With the tight lower bounds thereby obtained, the branch-and-bound procedure is activated to obtain an integer solution. Computational experience with the benchmark test instances confirms that our approach outperforms all the existing algorithms both in terms of the quality of solutions generated and the solution time.     

Aspect-oriented model-driven skeleton code generation: A graph-based transformation approach

Model-driven code generation has been investigated in traditional and object-oriented design paradigms; significant progress has been made. It offers many advantages including the rapid development of high quality code. Errors are reduced and the consistency between the design and the code is retained, in comparison with a purely manual approach. Here, a model-driven code generation approach based on graph transformations for aspect-oriented development is proposed. The approach has two main transformation activities. The first activity transforms a visual (graphical) model of the design into a formal, text-based notation that can be readily processed. The graphical model is created by the software designer and uses a UML profile for aspect-oriented software (i.e., FDAF) to represent aspects and their components. XML is the target notation for this step; the transformation uses the XML meta-model to ensure that the output complies with the language. The second activity transforms the XML model into AspectJ source code. The transformation uses the AspectJ meta-model to ensure the output complies with the language. The transformations from the extended UML model to XML and from XML to AspectJ code are fully automated. The transformation algorithms are based on graph transformations; tool support has been developed. Key technical issues in the approach are discussed, including performance, the amount of code generated, correctness, and adaptability, in addition to a comparison of the proposal with existing alternative approaches. The approach has been validated on three example systems: a banking system, classroom scheduling system, and an insurance system. The banking system example is presented in the paper.     

基于Web的B／S结构供电安全系统的实现技术

研究了基于Web的B／S结构系统设计方法和关键技术,并通过供电安全系统通用查询界面的设计讨论关键技术的实现方法。实践表明,所采用的一系列方法是有效的。     

A new deductive approach to planning

We introduce a new deductive approach to planning which is based on Horn clauses. Plans as well as situations are represented as terms and, thus, are first-class objects. We do neither need frame axioms nor state-literals. The only rule of inference is the SLDE-resolution rule, i.e. SLD-resolution, where the traditional unification algorithm has been replaced by anE-unification procedure. We exemplify the properties of our method such as forward and backward reasoning, plan checking, and the integration of general theories. Finally, we present the calculus and show that it is sound and complete. An earlier version of this paper was presented at the German Workshop on Artificial Intelligence, 1989.     

A semantic approach for automated test oracle generation

This paper presents the design, implementation, and applications of a software testing tool, TAO, which allows users to specify and generate test cases and oracles in a declarative way. Extended from its previous grammar-based test generation tool, TAO provides a declarative notation for defining denotational semantics on each productive grammar rule, such that when a test case is generated, its expected semantics will be evaluated automatically as well, serving as its test oracle. TAO further provides a simple tagging mechanism to embed oracles into test cases for bridging the automation between test case generation and software testing. Two practical case studies are used to illustrate how automated oracle generation can be effectively integrated with grammar-based test generation in different testing scenarios: locating fault-inducing input patterns on Java applications; and Selenium-based automated web testing.     

An accurate approach to roller path generation for robotic fibre placement of free-form surface composites

Due to their high stiffness and strength, composites are widely used in the aerospace industry. To manufacture composites, especially composites of free-form surface structure, process of robotic fibre placement (RFP) is widely used in industry. However, due to the complex geometry of the free-form surface, it is quite challenging to generate accurate roller paths for placing fibre on the surface for high composites quality. To address this problem, this work proposes an accurate roller path planning method using the differential geometry. The roller paths can ensure the specified small gaps and overlaps between two tows for high composite quality. This approach is applied to several examples, and their results verify the validity of this approach. It has great potential to be adopted in industry.     

Validation and automatic test generation on UML models: the AGATHA approach

The related economic goals of test generation are quite important for software industry. Manufacturers ever seeking to increase their productivity need to avoid malfunctions at the time of system specification: the later the defaults are detected, the greater the cost is. Consequently, the development of techniques and tools able to efficiently support engineers who are in charge of elaborating the specification constitutes a major challenge whose fallout concerns not only sectors of critical applications but also all those where poor conception could be extremely harmful to the brand image of a product.This article describes the design and implementation of a set of tools allowing software developers to validate UML (the Unified Modeling Language) specifications. This toolset belongs to the AGATHA environment, which is an automated test generator, developed at CEA/LIST.The AGATHA toolset is designed to validate specifications of communicating concurrent units described using an EIOLTS formalism (Extended Input Output Labeled Transition System). The goal of the work described in this paper is to provide an interface between UML and an EIOLTS formalism giving the possibility to use AGATHA on UML specifications.In this paper we describe first the translation of UML models into the EIOLTS formalism, and the translation of the results of the behavior analysis, provided by AGATHA, back into UML. Then we present the AGATHA toolset; we particularly focus on how AGATHA overcomes several problems of combinatorial explosion. We expose the concept of symbolic calculus and detection of redundant paths, which are the main principles of AGATHA's kernel. This kernel properly computes all the symbolic behaviors of a system specified in EIOLTS and automatically generates tests by way of constraint solving. Eventually we apply our method to an example and explain the different results that are computed.     

Validation and automatic test generation on UML models: the AGATHA approach

UML-based methodologies take more and more space in the software development domain. In addition, the need to validate applications as early as possible in the development cycle is now mandatory to satisfy cost and time-to-market constraints. In this context, this paper describes, first, how to bridge the gap between semiformal UML models and a formal technology ensuring test case generation. Second, the formal tool used to automatically generate test sequences, named AGATHA, is described in minute detail. Finally, this approach is illustrated throughout by a toy example of an elevator system.     

An effective and efficient parallel approach for random graph generation over GPUs

The widespread usage of random graphs   has been highlighted in the context of database applications for several years. This because such data structures turn out to be very useful in a large family of database applications ranging from simulation to sampling, from analysis of complex networks to study of randomized algorithms, and so forth. Amongst others, Erd?s–Rényi _Γv,p${\Gamma }_{v,p}$ is the most popular model to obtain and manipulate random graphs. Unfortunately, it has been demonstrated that classical algorithms for generating Erd?s–Rényi based random graphs do not scale well in large instances and, in addition to this, fail to make use of the parallel processing capabilities of modern hardware. Inspired by this main motivation, in this paper we propose and experimentally assess a novel parallel algorithm for generating random graphs under the Erd?s–Rényi model that is designed and implemented in a Graphics Processing Unit (GPU), called PPreZER. We demonstrate the nice amenities due to our solution via a succession of several intermediary algorithms, both sequential and parallel, which show the limitations of classical approaches and the benefits due to the PPreZER algorithm. Finally, our comprehensive experimental assessment and analysis brings to light a relevant average speedup gain of PPreZER over baseline algorithms.