GEMPACK: General-purpose software for applied general equilibrium and other economic modellers

This paper gives a brief overview of a new suite of software designed to make it relatively painless to implement large economic models, especially those in the computable general equilibrium (CGE) class. Whereas in the past a large element in the cost of building these models has been the writing of special-purpose code, the GEMPACK facility described here virtually eliminates the need for tailor-made programs. Moreover, because this facility is accessed via an essentially algebraic language, the GEMPACK computer text file used to implement an economic model provides an easily understood, but exhaustive and definitive, documentation of the model itself — something which only rarely has been available in the past.In this paper the CGE label applies to all numerical applications of general equilibrium (loosely speaking, multisectoral models whose detail gives an exhaustive coverage of the economy, and which recognise balance identities on both the revenue and costs sides of the transactions accounts of explicitly identified representative agents).     

A meta-model for formulating knowledge-based models of software development

In this paper, we introduce a knowledge-based meta-model which serves as a unified resource model for integrating characteristics of major types of objects appearing in software development models (SDMs). The URM consists of resource classes and a web of relations that link different types of resources found in different kinds of models of software development. The URM includes specialized models for software models for software systems, documents, agents, tools, and development processes. The URM has served as the basis for integrating and interoperating a number of process-centered CASE environments. The major benefit of the URM is twofold: First, it forms a higher level of abstraction supporting SDM formulation that subsumes many typical models of software development objects. Hence, it enables a higher level of reusability for existing support mechanisms of these models. Second, it provides a basis to support complex reasoning mechanisms that address issues across different types of software objects. To explore these features, we describe the URM both formally and with a detailed example, followed by a characterization of the process of SDM composition, and then by a characterization of the life cycle of activities involved in an overall model formulation process.     

GAUSSX: An integrated environment for GAUSS

This paper considers the boundary between classical statistical packages on the one hand, and programming languages on the other. The former are easy to use, but relatively inflexible, while the latter are very flexible, but have steep learning curves. A new class of software is now being developed that allows both flexibility, and ease-of-use. This concept is illustrated by the program GAUSSX, which provides an econometric shell for GAUSS.     

Features of multiregional and intertemporal AGE modelling with GEMPACK

The past few years have seen increasing use of multiregional and intertemporal (that is, forward-looking) applied general equilibrium (AGE) models. These models share the characteristic of rapidly expanding dimensions. Because multilateral trade models increase in size with the square of the number of regions and intertemporal models increase in proportion to the number of time periods, they can be very difficult to solve purely because of their size. This paper considers three recent models of these kinds, namely, GTAP, the Global Trade Analysis Project's multiregional model of the world; MRES, a multiregional forecasting model of Australia; and ORANI-INT, an intertemporal model of the Australian economy. Each of these has been implemented using the GEMPACK suite of general-purpose economic modelling software. In this paper we discuss features of GEMPACK which are especially relevant for multiregional and/or intertemporal models. These include an automatic facility to condense models to a manageable size; separation of equations, data, and closure/shocks; automatic creation of updated (that is, post-simulation) data files; and a solver that is well suited to intertemporal models with substantial elements of forward-looking behaviour. Each feature is illustrated via references to one or more of the three models mentioned above.     

星载软件可靠性模型应用研究及实践

为定量评估软件的可靠性指标,介绍了利用软件可靠性模型评估软件可靠性的过程和方法;针对某星载嵌入式软件的失效趋势,根据模型的选择原则和方法,以及模型的预测质量的对比,最终选择了指数模型作为可靠性评估模型。对该软件在轨运行情况进行了可靠性评估,开展了基于该软件可靠性测试数据的可靠性评估,评估结果给出了该软件的可靠性水平。     

产品线成本模型的比较与分析

为给软件产品线决策者应用软件产品线模型提供理论上的参考,综合分析比较了近年来的20种软件产品线模型,在对软件产品线模型的投资循环、重用方式、货币时间价值、经济函数、成本因子和重用成本等方面因素进行细致分析的基础上提出了软件产品线模型的比较框架,在该框架内着重分析了其中5种典型的软件产品线模型,对应用软件产品线开发方式的成本估算和投资分析做了细致分析,并对当前软件产品线模型时存在的问题和发展方向进行了探讨.     

A robust reconfiguration protocol for the dynamic update of component‐based software systems

This paper focuses on the dynamic reconfiguration of component‐based software systems. From a structural point of view, such systems are made of components linked together through their provided and required services, the code of components being defined by modules (e.g., jar files). Today, the ability to reconfigure component‐based systems at runtime faces limitations. Some component frameworks allow to dynamically reconfigure components – starting or stopping them, or changing how they are wired together for instance – but forbid any dynamic evolution of the modules defining their code. Other frameworks allow to dynamically update modules but at the cost of loosing control on component wires, preventing software architects or tools alike to decide how components are wired together. In this paper, we propose a component framework that addresses these limitations through a unified approach for the management of components and modules. Our approach uniquely enables to reconfigure both components and modules at runtime, without restrictions. We prototyped the proposed framework in Java and exercised various dynamic reconfigurations of component‐based systems. Furthermore, we formalized this framework and proved the correctness of its reconfiguration protocol with the Coq proof assistant. Copyright © 2017 John Wiley & Sons, Ltd.     

Applying software reliability models to a large industrial dataset

There are more reliability models in literature than experience reports of their application in industry. This paper tries to fill a bit of the hole, reporting the experience matured in Italtel SIT, a major Italian telecommunications company. The paper deals with the following subjects: goals of the experience; overview of the product under examination and its testing process; the method followed for conducting the experience; data analysis strategy; selection of the best models; analysis of their predictive capability; linking of phases by means of compression factors; and tools used to support the work.     

Development of a software tool for rapid,reproducible, and stakeholder-friendly dynamic coupling of system dynamics and physically-based models

System Dynamics (SD) modeling is well adapted to developing participatory environmental models. However, SD models are ill-suited for complex physical (e.g., groundwater) processes, and existing methods to couple them with physically-based models tend to be complex and inflexible. We here present Tinamit, a novel tool to couple SD and physically-based models in a rapid, reproducible, and stakeholder-friendly manner. Tinamit requires only a few lines of Python code to couple and simulate models (or, with its interface, no coding at all), which is expected to make model coupling more accessible to stakeholders and allow them to continue developing coupled models after the end of a funded project. We use Tinamit to couple a SD-based farmer economics model from Pakistan with a soil salinity model (SAHYSMOD) and analyze the trade-offs of various policies, of which canal lining with subsidies seemed promising. Such results cannot be readily obtained from either model alone.     

Segmented software cost estimation models based on fuzzy clustering

Parametric software cost estimation models are based on mathematical relations, obtained from the study of historical software projects databases, that intend to be useful to estimate the effort and time required to develop a software product. Those databases often integrate data coming from projects of a heterogeneous nature. This entails that it is difficult to obtain a reasonably reliable single parametric model for the range of diverging project sizes and characteristics. A solution proposed elsewhere for that problem was the use of segmented models in which several models combined into a single one contribute to the estimates depending on the concrete characteristic of the inputs. However, a second problem arises with the use of segmented models, since the belonging of concrete projects to segments or clusters is subject to a degree of fuzziness, i.e. a given project can be considered to belong to several segments with different degrees.This paper reports the first exploration of a possible solution for both problems together, using a segmented model based on fuzzy clusters of the project space. The use of fuzzy clustering allows obtaining different mathematical models for each cluster and also allows the items of a project database to contribute to more than one cluster, while preserving constant time execution of the estimation process. The results of an evaluation of a concrete model using the ISBSG 8 project database are reported, yielding better figures of adjustment than its crisp counterpart.     

基于蚁群算法的软件可靠性模型参数估计方法

由于软件可靠性模型大多是非线性模型,导致其参数难于估计。总结了常用的软件可靠性模型的参数估计方法,提出一种基于蚁群算法的可靠性模型参数估计方法。通过对Musa软件可靠性模型分类方案中三个不同类型模型（G-O模型、Weibull模型以及M-O模型）的实验,发现本算法对不同模型具有很好的适应性,解决了应用传统数值计算方法时的无法收敛问题;与粒子群算法相比,本算法的收敛速度比粒子群算法快一倍以上,且对于部分实验对象的拟合结果精度比粒子群算法高一个数量级以上。     

Synergistic verification and validation of systems and software engineering models

In this paper, we present a unified approach for the verification and validation of software and systems engineering design models expressed in UML 2.0 and SysML 1.0. The approach is based on three well-established techniques, namely formal analysis, programme analysis and software engineering (SwE) techniques. More precisely, our contribution consists of the synergistic combination of model checking, static analysis and SwE metrics that enables the automatic and efficient assessment of design models from static and dynamic perspectives. Additionally, we present the design and implementation of an automated computer-aided assessing framework integrating the proposed approach. Moreover, we discuss the related technical details and the underlying synergism. Finally, we illustrate the proposed approach by assessing a design case study that is composed of state machine and sequence diagrams.     

A composite complexity approach for software defect modelling

An approach is proposed to develop defect models for software components based on a categorical multivariate regression analysis. This modelling technique is useful when the software components are sufficiently small so that the assumption of a continuous normally distributed defect distribution is not valid. Library unit aggregations from five Ada projects are analysed to yield a composite complexity measure which is a function of both software complexity characteristics and development environment characteristics. The probabilities of various numbers of defects are derived from this composite complexity measure. The probability distributions are used to calculate subsystem level defects which are then compared to the actual defects.     

Applying a framework for the improvement of software process maturity

This article presents the results and lessons learned in the application of the Framework for the Modelling and Measurement of Software Processes (FMESP) in a software company dedicated to the development and maintenance of software for information systems. The aim of FMESP is to provide companies with a conceptual and technological framework for the management of their process models and measurement models in an integrated way. Modelling and measurement are two key factors to promote continuous process improvement. As a result, important benefits were obtained. The company improved the maturity of its processes which allowed it to obtain the ISO 9000 certification. From a research point of view, Action‐Research was successfully applied and as a result the framework was improved and important feedback was obtained, bringing to light new important issues which will be tacked in future work. Copyright © 2005 John Wiley & Sons, Ltd.     

Selecting software reliability growth models and improving their predictive accuracy using historical projects data

During software development two important decisions organizations have to make are: how to allocate testing resources optimally and when the software is ready for release. SRGMs (software reliability growth models) provide empirical basis for evaluating and predicting reliability of software systems. When using SRGMs for the purpose of optimizing testing resource allocation, the model's ability to accurately predict the expected defect inflow profile is useful. For assessing release readiness, the asymptote accuracy is the most important attribute. Although more than hundred models for software reliability have been proposed and evaluated over time, there exists no clear guide on which models should be used for a given software development process or for a given industrial domain.Using defect inflow profiles from large software projects from Ericsson, Volvo Car Corporation and Saab, we evaluate commonly used SRGMs for their ability to provide empirical basis for making these decisions. We also demonstrate that using defect intensity growth rate from earlier projects increases the accuracy of the predictions. Our results show that Logistic and Gompertz models are the most accurate models; we further observe that classifying a given project based on its expected shape of defect inflow help to select the most appropriate model.     

适用于动态软件体系结构的扩展的Z描述语言

动态软件体系结构语言已成为描述复杂软件体系结构的重要工具,然而许多描述语言都是静态的,并不能对动态软件体系进行描述。为此,对经典Z描述语言进行扩展,主要通过对构件、连接件和它们的添加以及删除来达到动态演化的目的。实例分析表明了这种扩展的可行性。     

Reconciling software development models: A quasi-systematic review

Purpose

The purpose of this paper is to characterize reconciliation among the plan-driven, agile, and free/open source software models of software development.

Design/methodology/approach

An automated quasi-systematic review identified 42 papers, which were then analyzed.

Findings

The main findings are: there exist distinct - organization, group and process - levels of reconciliation; few studies deal with reconciliation among the three models of development; a significant amount of work addresses reconciliation between plan-driven and agile development; several large organizations (such as Microsoft, Motorola, and Philips) are interested in trying to combine these models; and reconciliation among software development models is still an open issue, since it is an emerging area and research on most proposals is at an early stage.

Research limitations

Automated searches may not capture relevant papers in publications that are not indexed. Other data sources not amenable to execution of the protocol were not used. Data extraction was performed by only one researcher, which may increase the risk of threats to internal validity.

Implications

This characterization is important for practitioners wanting to be current with the state of research. This review will also assist the scientific community working with software development processes to build a common understanding of the challenges that must be faced, and to identify areas where research is lacking. Finally, the results will be useful to software industry that is calling for solutions in this area.

Originality/value

There is no other systematic review on this subject, and reconciliation among software development models is an emerging area. This study helps to identify and consolidate the work done so far and to guide future research. The conclusions are an important step towards expanding the body of knowledge in the field.     

A Dynamic Integrated Framework for Software Process Improvement

Current software process models (CMM, SPICE, etc.) strongly recommend the application of statistical control and measure guides to define, implement, and evaluate the effects of different process improvements. However, whilst quantitative modeling has been widely used in other fields, it has not been considered enough in the field of software process improvement. During the last decade software process simulation has been used to address a wide diversity of management problems. Some of these problems are related to strategic management, technology adoption, understanding, training and learning, and risk management, among others. In this work a dynamic integrated framework for software process improvement is presented. This framework combines traditional estimation models with an intensive utilization of dynamic simulation models of the software process. The aim of this framework is to support a qualitative and quantitative assessment for software process improvement and decision making to achieve a higher software development process capability according to the Capability Maturity Model. The concepts underlying this framework have been implemented in a software process improvement tool that has been used in a local software organization. The results obtained and the lessons learned are also presented in this paper.     

Understanding agile software development practices using shared mental models theory

ContextAgile software development is an alternative software development methodology that originated from practice to encourage collaboration between developers and users, to leverage rapid development cycles, and to respond to changes in a dynamic environment. Although agile practices are widely used in organizations, academics call for more theoretical research to understand the value of agile software development methodologies.ObjectiveThis study uses shared mental models theory as a lens to examine practices from agile software methodologies to understand how agile practices enable software development teams to work together to complete tasks and work together effectively as a team.MethodA conceptual analysis of specific agile practices was conducted using the lens of shared mental models theory. Three agile practices from Xtreme Programming and Scrum are examined in detail, system metaphor, stand-up meeting, and on-site customer, using shared mental models theory.ResultsExamining agile practices using shared mental models theory elucidates how agile practices improve collaboration during the software development process. The results explain how agile practices contribute toward a shared understanding and enhanced collaboration within the software development team.ConclusionsThis conceptual analysis demonstrates the value of agile practices in developing shared mental models (i.e. shared understanding) among developers and customers in software development teams. Some agile practices are useful in developing a shared understanding about the tasks to be completed, while other agile practices create shared mental models about team processes and team interactions. To elicit the desired outcomes of agile software development methods, software development teams should consider whether or not agile practices are used in a manner that enhances the team’s shared understanding. Using three specific agile practices as examples, this research demonstrates how theory, such as shared mental models theory, can enhance our understanding regarding how agile practices are useful in enhancing collaboration in the workplace.     

Investigating ARIMA models of software system quality

In this paper, we investigate how to incorporate program complexity measures with a software quality model. We collect software complexity metrics and fault counts from each build during the testing phase of a large commercial software system. Though the data are limited in quantity, we are able to predict the number of faults in the next build. The technique we used is called times series analysis and forecasting. The methodology assumes that future predictions are based on the history of past observations. We will show that the combined complexity quality model is an improvement over the simpler quality only model. Finally, we explore how the testing process used in this development may be improved by using these predictions and suggest areas for future research.