The authors present a reasoned synopsis of the state of the art of compiler techniques. A classification scheme is employed that divides compilers according to two layers. The first layer is the input layer, dealing with the kind of language that the ...

This paper discusses some problems caused by inadequately characterizing distributed and system architectures. It presents a classification system for decomposing distributed systems and presents a few simple test cases. To allow system designers to characterize different aspects of their environments, we have started a collection of simple Quick-Tests.

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In this paper we argue for an alternative way of designing cooperative constraint solver systems using a control-oriented coordination language. The idea is to take advantage of the coordination features of MANIFOLD for improving the constraint solver ...

There is substantial current interest in the use of remotely sensed images to study littoral processes. Of particular interest is using the interaction of the ocean waves with the bottom to infer the water depth in coastal areas. Testing the accuracy of processing and analysis methods requires a known set of bottom depths at many points in the images to compare with depths extracted. Such knowledge is not available for most near-shore areas. Consequently, we have developed a simulator which produces a time series of images showing sea surface elevation for waves moving over a specified piecewise linear bottom of moderate slope. It provides a good approximation to the real sea surface for a wide range of conditions. Hence it can produce controlled datasets for many purposes in shallow-water research. The program uses linear wave theory to model a statistical realization of a deep-water wave field, with a realistic frequency spectrum and directional spreading, and applies the appropriate modifications for shoaling. Several examples show that the program produces reasonable results, indicating it should be a useful analytical tool in a range of problems.

Domain Analysis is the process that identifies the relevant objects of an application domain. The goal of Domain Analysis is Software Reuse. The higher is the level of the life-cycle object to reuse, the larger are the benefits coming from its reuse, the harder is the definition of a workable process. Frameworks are excellent candidates for Domain Analysis: they are at a higher level than code but average programmers can understand them.This paper presents the main features of Sherlock, a domain analysis process for the extraction of reusable frameworks, and discusses the impact that Sherlock has on the software process, in particular concerning reuse practices. Sherlock is based on both FODA and Proteus domain analysis techniques. The input of Sherlock is an informal description of the domain based on other domain applications, literature, user requirements, and interviews with domain experts. The output of Sherlock is a set of architectural models (the domain frameworks and patterns), taxonomies of permanencies and variabilities, objects models focusing on the common domain objects. The introduction of Sherlock in the software process requires the definition of new roles and has a valuable impact on reuse practices. We present in this paper a case study: the application of Sherlock at Thera S.p.A., a software company located in Brescia, Italy.

Since reuse costs are often higher than expected, several approaches to development with reuse have been proposed. Among the most interesting is the idea of frameworks: sets of single components collaborating according to predefined cooperation rules. This approach can have a great impact on the reusability of parts of a software system, but it is not an easy task to give a quantitative measure of this reusability. The existing reusability metrics can be used, but the results are not fully satisfactory, since they do not take into account the peculiar characteristics of a framework and the particular way it is reused (a mix between black box reuse and white box reuse). For these reasons, a set of criteria adapting the traditional reusability metrics is proposed. These criteria try to evaluate the four main factors affecting the reusability of a framework: portability, adaptability, understandability, and confidence.

Software reuse can be very useful in increasing the productivity and the quality level of a company, but the costs of this kind of investment are not always covered by the advantages it brings. It is particularly important to be able to correctly analyze the cost implied by software reuse in order to decide whether to adopt it or not. Even when a reuse policy has been adopted, reuse is not always the right solution and there are situations in which it is more convenient to develop a component from scratch. It is difficult to obtain a mathematical model for the evaluation of the effort required by the adaptation of a component in a new context. A different approach is proposed where the estimation is made using the knowledge and the experience gained from previous cases and stored in an ad-hoc base.

Software developers often meet the problem of creating new components of an application that someone probably has already produced. Without having effective reuse tools usually it is more natural to create new components from scratch than to seek for useful elements in other programmes and/or systems.In the field of simulation of Flexible Manufacturing Systems (FMS) this issue often occurs, when different systems with some similar features have to be managed. FMSs are highly automated production systems with minimal human control. FMS usually consist Flexible Manufacturing Cells (FMCs). An FMC is considered as a group of one or more machine tools, robots, adjacent mechanical elements, tool and fixture supporting workstations and an internal transport system.The components of different FMSs and FMCs are the same type of machine tools, transfer equipment, etc. In the relevant aspects they usually differ from each other only in their amounts and working parameters. This fact itself breeds the idea of reuse of FMS and FMC simulation model elements.Simulation can be used for analysing the behaviour of an existing or would-be system. It is useful for calculating utilisation statistics, finding bottlenecks, pointing out scheduling errors, and even for creating manufacturing schedules. Simulation is a very effective technique for dynamic analysis, but it is short of optimising ability. A satisfactory solution can be obtained through modelling and simulating alternative approaches with iteration.There are many concepts, object classes, and lines of source code created, that could be reused in the new applications. Usage of reuse methodology and practice will reduce our efforts in developing new systems.In this paper the reuse of the components of simulation models in a hybrid simulation and scheduling system for new simulation applications will be introduced. This simulation-scheduler system has been implemented as a combination of a traditional simulation language (SIMAN/Cinema) and an intelligent expert environment (G2). The design methodology used for model development is based on the object-oriented Rational Rose CASE tool and on a use-case model.

Software developers often meet the problem of creating new components of an application that someone probably has already produced. Without having effective reuse tools usually it is more natural to create new components from scratch than to seek for ...