Software Reuse

No seguimento dum artigo anterior acerca da análise de regressão não-linear (simples) utilizando a ferramenta Solver® do Excel® (Esteves, 2010) propõe-se neste artigo a apresentação do R, uma linguagem de programação e um ambiente para computação estatística e gráfica, através da sua aplicação na “descrição” de relações estatísticas (não-lineares) entre variáveis.

An established approach to cost and risk reduction of space systems is the use of heritage systems. A heritage system is a system which is based on a proven system design. A design is a set of engineering drawings, plans, etc. which are used to manufacture a system [1]. Heritage is the degree to which a system is proven. One example for a system with a high degree of heritage would be a communication satellite where satellites with similar designs have been successfully flown over a dozen times in the same orbit. In the following, an element of a system is called “component”.  Almost all newly developed space systems to some degree rely on preexisting components. Recent examples are NASA’s Space Launch System (SLS), and the Ares V and Area I vehicles for the Constellation program. All these vehicle designs rely on components from the Space Shuttle program, such as the solid rocket boosters and the external tank. However, the use of heritage systems is not as straight forward as one might expect. According to the Governmental Accountability Office (GAO), more than 50% of NASA’s space missions encountered problems linked to heritage components [2]. Heritage components were responsible for some notable catastrophic failures, for example the Ariane 5 Flight 501, where the guidance software was carried over from Ariane 4 [3]. It was a proven piece of software. However, the software was incompatible to the new system architecture in which it operated [3]. Other failures include the Mars Observer mission, where the spacecraft bus was proven for operation in low-Earth orbit (LEO) [4]. According to the failure investigation report, the most probable cause of the failure was a leaking valve. Due to the longer storage duration compared to LEO, the previously reliable valve started to leak. Besides mission failures, the analysis of past space programs shows that the use of heritage technologies can lead to reductions in development cost and risk but can also lead to cost and schedule overruns, if not properly managed [2]. Interviews conducted with engineers from various space companies confirmed that heritage technologies are assessed ad-hoc and no systematic methodology exists. Such a methodology could be beneficial, in particular during the early stages of development, where heritage-related risks can be mitigated easier than later on.

This paper presents a framework and methodology for assessing heritage in the early stages of development.

The methodology allows for identifying heritage with respect to a new application as well as identifying areas where it is missing. Second, possible modifications to the design can be assessed in terms of their impact on the expected development schedule and cost. Lastly, a system design which fits a new application is useless, if it cannot be implemented. Therefore, the ability to assess technological capabilities for implementing a system is also vital for assessing heritage systems. The methodology is applied to a case study which compares the Saturn V with SLS variants.

Context: Mobile Cloud Computing (MCC) represents the state-of-the-art technology that unifies mobile computing and cloud computing to develop systems that are portable yet resource sufficient. Mobile computing allows portable communication and context-aware computation, however, due to the energy and resource constraints mobile computing lacks performance for computationally intensive tasks. Cloud computing model uses the 'as a service' model-providing hardware and software services-to offer virtually unlimited storage and processing resources. The integration of mobile and cloud computing has given rise to the MCC systems that are portable, context-aware and resource sufficient. Challenges and Solution: To develop the MCC systems, some recurring challenges such as connectivity, context-awareness, portability and security must be addressed during the system design and architecting process. One way to address these challenges is to use the best practices and repeatable solutions to design and architect the MCC systems. In this research, we aim to utilise the empirically discovered patterns that support reusable design knowledge for architecture-driven development of the MCC systems. We follow a three-step process to empirically discover, document and apply patterns for architecting mobile cloud systems. Specifically, we have discovered three patterns as generic and reusable solutions for MCC systems. We demonstrate the applicability of the patterns based on a case study for architecture-centric development of the MCC patterns. The propose research aims to advance the state-of-the-art on reusable and knowledge-driven architecting of the MCC systems.

Las experiencias de la industria en reusabilidad del software, demuestran que esta no depende específicamente de aspectos tecnológicos sino de aquellos organizativos y de motivación. No obstante las tecnologías pueden ayudar al respecto. Se describe como la orientación a objetos
contribuye en los diferentes niveles de reutilización: bibliotecas de clases, patrones de diseño y
arquitecturas.

This study investigated and develops a strategy for software reuse for the Constellation Program. The study team consisted of a group of multidisciplinary experts from across the NASA Centers, with collective expertise spanning the lifecycle of software engineering from research through operations and software obsolescence. The team investigated what software reuse would mean in the context of the Constellation Program, the benefits that might be earned, and the risks to be mitigated.

The focus of existing open source software (OSS) research has been on how and why individuals and firms add to the commons of public OSS code - that is, on the "giving" side of this open innovation process. In contrast, research on the corresponding "receiving" side is scarce. We address this gap, studying how existing OSS code is reused and

Current software cost estimation models, such as the 1981 Constructive Cost Model (COCOMO) for software cost estimation and its 1987 Ada COCOMO update, have been experiencing increasing difficulties in estimating the costs of software developed to new life cycle processes and capabilities. These include non-sequential and rapid-development process models; reuse-driven approaches involving commercial off-the-shelf (COTS) packages, re-engineering, applications composition, and applications generation capabilities; object-oriented approaches supported by distributed middleware; and software process maturity initiatives. This paper summarizes research in deriving a baseline COCOMO 2.0 model tailored to these new forms of software development, including rationale for the model decisions. The major new modeling capabilities of COCOMO 2.0 are a tailorable family of software sizing models, involving Object Points, Function Points, and Source Lines of Code; nonlinear models for software reuse and re-engineering; an exponentdriver approach for modeling relative software diseconomies of scale; and several additions, deletions and updates to previous COCOMO effort-multiplier cost drivers. This model is serving as a framework for an extensive current data collection and analysis effort to further refine and calibrate the model's estimation capabilities.

The paper describes results of an empirical study, where some hypotheses about the impact of reuse on defect-density and stability, and about the impact of component size on defects and defect-density in the context of reuse are assessed, using historical data (“data mining”) ...

This paper aims at identifying some of the key factors in adopting an organization-wide software reuse program. The factors are derived from practical experience reported by industry professionals, through a survey involving 57 Brazilian small, medium and large software organizations. Some of them produce software with commonality between applications, and have mature processes, while others successfully achieved reuse through isolated, ad hoc efforts. The paper compiles the answers from the survey participants, showing which factors were more associated with reuse success. Based on this relationship, a guide is presented, pointing out which factors should be more strongly considered by small, medium and large organizations attempting to establish a reuse program.

The basic idea behind building Reusable software components is to design interchangeable parts from other industries to the software field of construction. A reuse library or component reuse repository organizes stores and manages reusable components. The biggest advantage of the building reusable software components is that it reduces the time and energy in developing any software. Frameworks provides a standard working system through which user 's main focus is on developing desired modules instead of developing lower level details. By using this facility the software developers can spend more time in developing the requirement of software, rather than preparing the tools of application development. Framework is set of reusable software program that forms the basis for an application. Frameworks help the programmers to build the application quickly .At its best code reuse is accomplished through the sharing of common classes and/or collections of functions, frameworks and procedures. This paper describes how to build the code level reusable components and how to design code level components. Finally providing coding guidelines, standards and best practices used for creating reusable code level components and guidelines and best practices for making configurable and easy to use.

Nowadays the number of software components that coexist within a motor vehicle can be counted by hundreds, however in the automotive industry the software development process is neither as mature nor evolved as the vehicle manufacturing process, where there are well defined methods and practices to reuse components at design and architectural level. In this paper, authors propose a metamodel, developed with software engineering techniques, aimed to offer an alternative that could allow to the expert engineers involved on the development of software components for automobile vehicles to reuse software components related with the driving assistance systems ABS; ASR, ESP and Traction Control.

We have integrated the feature modeling of Feature- Oriented Domain Analysis (FODA) into the processes and workproducts of the Reuse-Driven Software Engineering Business (RSEB). The RSEB is a use-case driven systematic reuse process: architecture and reusable subsystems are first described by use cases and then transformed into object models that are traceable to these use cases. Variability in the RSEB is captured by structuring use case and object models using explicit variation points and variants. Traditional domain engineering steps have been distributed into the steps of the architectural and component system development methods of the RSEB. But the RSEB prescribes no explicit models of the essential features that characterize the different versions. Building on our experience in applying FODA and RSEB to the telecom domain, we have added explicit domain engineering steps and an explicit feature model to the RSEB to support domain engineering and component reuse. These additio...

This paper describes a technique for formalizing metrics
for COTS-based architectures. This technique is built upon
the UML 2.0 metamodel and uses OCL as a metrics definition language.
As a proof of concept, an example based upon a set of
reusability metrics for fine-grained JavaBeans components
is presented

Economic and social issues were pointed out as Software
Engineering (SE) challenges for the next years, since the field needs
to treat issues beyond the technical side, which requires observing it
in another perspective. In this sense, the study of software
ecosystems is an emerging discipline that investigates the complex
relationships among companies in the software industry.
Companies work cooperatively and competitively in order to
achieve their strategic objectives. They must engage in a new
perspective, now also including third parties motivations and
movements in the ecosystem, besides their own business
perspective. Inspired from properties by natural and business
ecosystems, a software ecosystem covers technical and business
aspects of software development as well as partnership among
companies. In this paper, we undertake a review on software
ecosystems status as an emerging research topic in SE community,
i.e., mapping what is currently known about software ecosystems
and also analyzing them in a three-dimensional perspective in SE,
i.e., technical, business and social. We observed that software
ecosystems research is concentrated in eight main areas in which
the most relevant ones are open source software, ecosystem
modeling, and business issues. This paper also contributes to
summarize the body of knowledge and presents a research agenda
in software ecosystems.

Software component reuse is the software engineering practice of developing new software products from existing components. A reuse library or component reuse repository organizes stores and manages reusable components. This paper describes how a reusable component is created, how it reuses the function and checking if optimized code is being used in building programs and applications. Finally providing
coding guidelines, standards and best practices used for creating reusable components and guidelines and best practices for making configurable and easy to use.

Open Source Software (OSS) represents an extremely valuable resource that is reused systematically almost in every software project. The reuse of OSS components however is restricted to ready-made components and developers who want to reuse code that exists in OSS projects but is not offered as a black-box component often resort to copying existing code and adapting it in their projects. OPEN-SME is a European research project which aims at providing ready-to-use OSS components that originate from existing OSS projects but are not necessarily provided as such. In this work we describe the Component Adaptation Environment (COPE)tool that was developed in the context of the OPEN-SME project and enables software experts, called reuse engineers, to extract components from OSS projects, test them and provide test documentation, validate them with Model-Based Testing techniques, package them and upload them in a component repository for reuse.

Domain specific modeling services, especially when made available to pipeline systems that transport oil and gas, constitute an interesting but very challenging domain. It poses fundamental problems for requirements engineering, software architecture, and their relationship. We propose a novel, domain-based framework for requirements engineering for this class of applications. The framework addresses the key concepts in this field, such as changing complexities for design platforms and domain specific requirements. We report experimental lessons learned on this framework and suggest requirements analysis products for documentation and future system design directions.