Evolving strategies for software architecture and reuse

Context: Successful software systems continuously evolve to accommodate feature requests of a diverse customer-base. At some point during this evolution, the variety of customer needs and increased system complexity suggests the consideration of a software product line (SPL).Aim: The goal of this research is to support the decision maker facing the enhancement of an evolving software system (ESS) by determining the most appropriate product line design (out of a given set of candidate SPL portfolios) to minimize the technical risk and maximize the business value.Method: The proposed method called OPTESS is aimed at finding an evolution plan for the ESS which optimizes both the given technical and business objectives. Business analysis using a value-based pricing mechanism is applied to a set of initially proposed SPL portfolios (for enhancing the ESS) such that profit is maximized. Technical analysis is applied to the same initially proposed SPL portfolios to minimize the risk of failure of ESS due to implementation of new features. Business and technical analyses improve the performance of solutions for their respective objectives by modifying the feature sets of candidate SPL portfolios. OPTESS helps the decision maker select a plan for enhancement of an ESS by performing trade- off analysis between economic and technical objectives.Results: The method was initially evaluated through a case study for a set of 9 new candidate features to be added to an open source text editing system called jEdit. OPTESS helped the decision maker to identify 3 non-dominated solutions judged to be the best contenders for addition when considering both technical and economic criteria.

Over the last few years, we have seen the transformation of the traditional monolithic enterprise, in which all operations were performed in-house, to the extended enterprise, which consists of a network of collaborating entities. Global operations, outsourcing, and increasing specialization have all contributed to this trend. One challenge facing the extended enterprise is how to reconnect the information flows and business processes that were disconnected as the enterprise disaggregated. The emergence of web services, service-oriented architectures, and business process modeling and execution standards are helping to address this challenge. Our contention is that the next phase of evolution is the rise of the intelligent enterprise, which is characterized by being able to adapt quickly to changes in its operating environment. The intelligent enterprise monitors its own business processes and its interactions with customers, partners, suppliers, and collaborators; it understands how this information relates to its business objectives; and it acts to control and optimize its operations to meet its business objectives. Decisions are made quickly and accurately to modify business processes on the fly, dynamically allocate resources, or change business partners (e.g., suppliers, service providers) and partnerships (e.g., establish new service level agreements). This talk will describe challenges in managing the business operations of an intelligent enterprise. While a plethora of tools exist for managing the IT infrastructure (servers, storage, and network resources) of the enterprise, there is little systematic support today for the closed loop management and control of business operations. We will describe technology approaches to intelligent business operations management that we are pursuing at HP Labs., the progress we have made, and some open research questions.

A major cause of many complications in the field of software architectures is the lack of appropriate abstractions for separating, combining and encapsulating concerns of various kinds in architectural descriptions. Architectures of most complex software-intensive systems involve concerns that inherently crosscut the natural boundaries of the elements composing the architecture descriptions. Crosscutting concerns intersect the common modularity of systems as prescribed by their architecture descriptions, by traversing both the components and connectors, i.e., the relationships among the components. Crosscutting concerns are critical aspects of many architectural problems. However, architectural descriptions written in special-purpose languages (ADLs) like Wright, Darwin, Rapide and Acme should support descriptions of multiple structures, which include diagrams, models and views, that intentionally address different kinds of concerns. ADLs should show how various concerns affect each other in architectural designs; they should also allow one to identify, analyze and elaborate architectural concerns that cut across several software components, such as transactions, security, load balancing, synchronization, reuse, customization, scalability, etc.; they should, but they do not. This dissertation presents a new approach to software architecture that is suitable for supporting concern-oriented development and documentation of architectures for software-intensive systems. This approach allows for creating and documenting a multidimensional software structure that is referred to as concern-oriented software architecture; it provides new mechanisms for encapsulating individual concerns into independent architectural constructs. The ultimate goal of this new approach is to provide support for achieving design by concerns all through the development and description of software architectures. Moving towards this goal, we present a particular concern-oriented architectural framework called Perspectival Concern-Spaces (PCS). The PCS Framework offers a flexible and extensible means a) for supporting advanced separation of concerns in architectural design, and in the construction and evolution of software-intensive systems; and b) for filling the gap between architectural descriptions and modern software development artifacts. To show the feasibility of the proposed approach, we provide new modeling techniques that are used to describe and apply an aspect-oriented architectural pattern, called the On-demand Remodularization pattern. We give several examples of how the PCS Framework can be used to integrate concern-oriented architectural documentations with mainstream software development artifacts.

Metric-based Evaluation of Implemented Software Architectures

To achieve their business objectives, software developing companies employ different technical and managerial strategies concerning architecture and reuse. These strategies include component‐based development, software platforms, product lines and highly configurable code bases. Frameworks for describing these strategies have recently emerged, presenting them in orders of ‘increasing maturity’, with researchers declaring specific architectural strategies to be more mature than others. Such frameworks can be useful in helping a company realize a particular architectural strategy but they do not provide guidelines concerning which architectural strategies are appropriate for companies in particular situations.Different companies have different needs—the business context and business goals of a company will determine which architectural strategy is most suitable for that company. There is no universally ‘most mature’ strategy. In this article, we have studied architectural situations in thirteen companies in order to determine why and how these companies have moved between architectural strategies and how these relate to reuse and business goals and conditions. We present a framework for describing these and provide guidelines for companies about how to traverse the maze of architectural evolution. Copyright © 2007 John Wiley & Sons, Ltd.

Large and complex software systems cannot be created in one piece. They need to be separated into manageable units, i.e., modules, which can be developed independently from each other. Precise definition and documentation of the modules and other software artifacts is essential for a successful software project. The module documentation is part of the overall software architecture documentation. However, nowadays most of the utilized tools for documenting software architectures (e.g., word processors) are not fully sufficient for this task. This thesis provides a concept for an extensible tool, which is specialized for documenting software architectures and modules. The concept supports management and visualization of explicitly definable relations, e.g., dependencies among modules or references to external implementation artifacts. Moreover, this thesis suggests a template for module documentation based on its concept. Finally, a proof of concept prototype is implemented and evaluated with promising results.

This special issue is based on a collection of selected papers presented at the Fifth International Conference on Advanced Computing held in Chennai (Madras), India in December 97. The International Conference on Advanced Computing is organized annually in India by the Advanced Computing Society (ACS) which is a premier professional society set up in India to cater to the broad interests in the area of Advanced Computing. One of the significant activities of the Society is to organize regular Meetings/Conferences/Symposia. The Conferences are held annually in India during December. Out of the shortlisted papers presented at the Conference held in Chennai (Madras) during December 97, the following six papers were finally selected after a second round of detailed review of the papers. The first paper On designing and implementing collaborative system using Java-RMI by Rajeev R. Raje, Snehasis Mukhopadhyay, Michael Boyles and Nila Patel describe the use of Java-RMI in designing a collaborative information classifier. The principles of RMI, the details of the prototype, and some preliminary results are presented. The paper primarily concentrates on web-based computing paradigms. In the second paper A framework for performance-based program partitioning , Ram Subramanian and Santosh Pande present an efficient and accurate performance model based program-partitioning approach for parallel architectures. The interactions between computation and communication are captured through behavioral edges . The approach yields significant performance improvement. The third paper DDSCHED: a distributed dynamic real-time scheduling algorithm by Anup K. Bhattacharjee, K. Ravindranath, R. Mall and A. Pal presents a dynamic soft real-time scheduling algorithm for distributed systems. The algorithm is based on a local scheduler and a distributed scheduling scheme. The algorithm takes care of the network delays assuming that the communication protocol is CSMA/CD. In the fourth paper Generic operational decomposition for concurrent systems semantics and reflection , Annie Marcoux, Christine Maurel, Frederic Migeon and Patrick Salle discuss about the reflection in concurrent languages, particularly in actor-based languages. The main objective of the paper is to extend concurrent systems to reflection. The authors present a modular and dynamic description of entity operational management, and extend the decomposition to obtain reflective entities. The fifth paper Parallel programming using visual patterns by A. S. M. Sajeev proposes a two level approach to parallel programming within the context of a visual environment. The first level is the specification of patterns encapsulating process communation and synchronization, and the second level is the use of patterns for parallel programming. The approach encourages reuse of patterns. In the sixth paper An application framework for dynamic distributed software architectures , G. R. Ribeiro-Justo and P. R. F. Cunha present an object-oriented application framework for developing evolving (reconfigurable) software architectures for distributed systems. The application framework is called C++CL. Such a requirement is encountered in banking, industrial control and telecommunications applications. We are extremely thankful to the following reviewers who have helped us in reviewing the papers submitted for this special issue: Lawrence Jenkins N. Mohan Ram Nishit Narang Rajeev Shorey Sameer Adhikari K. Balaji K. Rajan Sumit Kasera Subhrajyothi Bhar Pankaj Sethi Ravindranath Kokku Guest Editors: L. M. Patnaik, Ravi Mittal and K. M. Mehta

Software development has undergone various stages of paradigms - the very last one is called Object-Oriented (O-O) paradigm. Typical of this paradigm has been culminated by several OO programming languages such as C++, Java and VB. With the advent of Internetworking and evolvement of web technologies, business needs, especially isolated service requests/components, put a new demand on new software architecture. Existing models are examined in the light of their constraints and limitations to meet these constant changing business requirements. Service-oriented Architecture (SOA), as the next generation software architecture and through the utilization of the web service, XML and other related technologies provides viable working solution to implement dynamic e-business. This paper discusses SOA model and how it fits into implementing dynamic e-business solutions.

Customers, being important assets to an enterprise, directly relate to the latter’s profitability and survival. Customers buy products to generate revenue. Their feedbacks also promote the improvement of products and drive an enterprise to develop forward. With or without an information system, good CRM (customer relationship management) is extremely important for an enterprise to achieve its profit targets. Though a non-profit organization (NPO) does not pursue profits, it has service objects, concrete products or services for achieving its vision, or supporters of its vision. The spirit and practice of making every effort possible to know their customers which is usually adopted by an enterprise in order to achieve its business objectives could also be seen to exist in non-profit organizations. It’s just such spirit and practice that is slightly different in form or the goal. If adjusted, the application of CRM in enterprises could also effectively help non-profit organizations to understand more clearly the practice they have to take in order to achieve their visions and understand the objects of their services or supporters. Exampled with the church, this study explores whether CRM helps the church and how should churches apply CRM. Leaders at all levels in the church pastoral relationship could be compared to managers at all levels in a corporate organization, while PRM (pastoral relationship management) applied to churches via CRM could generate specific impacts on group pastoral care, group development strategies, equipment of true believers, business as mission, family as mission, church planting and preaching.

Current literature on software product development suggests that it is possible to develop the software architecture alongside the software itself using an evolutionary product development process. That is, engineers can delay finalization of product architecture until well along in the product development process. If there is a financial incentive to delay “freezing” the architecture until the latter stages of product development, could this process also be used for manufactured goods? This paper provides some examples of delayed architectural decisions, discusses when there might be financial incentives, and then shows some interesting new practices which might facilitate this process. It then comments on the applicability of this evolutionary approach to the development of the product architecture of manufactured goods, and concludes that manufactured goods can potentially realize the gains derived from an evolutionary approach to architectural design. © 2004 Wiley Periodicals, Inc. Syst Eng 7: 144–152, 2004

The information systems (IS) audit in public sector organisations is generally conducted to provide assurance about the effectiveness of IS controls, processes, resources, operations, and value for money in the IS investment. Public sector organisations are being confronted with various new demands from businesses, the public and other stakeholders because of the high level of IS investment, which takes long to complete and involves uncertainty of performance. This research argues that the current IS audit practice does not take a broad enough view in assessing the overall system. Hence, it is particularly challenging for an IS auditor not only to identify how well the IS supports the overall business objectives, but also to justify the continuity of IS operation and to produce an effective IS audit report. There have been several cases in which IS were unsuccessful and did not perform as the users expected. Due to the current IS audit practice, IS auditors are unable to recognise any inherent limitations that may exist in the design, development and implementation of application systems that will impact on the organisation’s objectives and operational activities. Sustainability is a relevant and practical way to deal with limitations found in IS audit practice. Sustainability is future oriented and concerned with holistic and integrated systems consisting of humans, nature, social and technology infrastructure. This research is conducted with the goal of incorporating sustainability within the IS audit framework as a strategy to minimise IS control risk, to reduce inherent risks faced by the IS auditors and to produce effective IS audit reports. This research found that the proposed framework known as the Sustainability Driven Information System Audit (SISA) is an appropriate alternative that can overcome these shortcomings, and effectively address risks associated with IS controls. SISA is also considered to reduce uncertainties in decision making by reviewing results, processes and input. It facilitates coordination and communication to produce an audit report that provides effective value to the key stakeholders and the public. This research also studies the appropriate method for IS auditors to make audit judgements, particularly in measuring IS controls. The applicability of the SISA framework to a real case study has been found to be very promising. The result showed that a systematic and numerical approach is suitable for prioritising audit criteria and in order to emphasise the key areas of concern for the audit purpose. The results indicate that the sustainability approach is a practical and reasonable method that can be employed at any public sector organisation. This research contributes theoretically, methodologically and practically to the IS audit body of knowledge.

Parallel, distributed and network-based computing is a continuosly evolving field, driven by progress in microprocessor architecture and interconnection technology, as well as by the needs of computing- and data-intensive applications in science and engineering, and, more recently, in business. This field is currently undergoing a significant change, because of the development of multicore and manycore processors, GPUs, and FPGAs, which are the new building blocks of parallel architectures. At the other end of the parallel and distributed computing scenario, computational grids are far from being a mature infrastructure and are evolving toward cloud computing, to get a higher level of virtualization. The availability of programming models, algorithms and software tools capable of harnessing the processing power offered by the new technologies is a key issue to make them usable by application developers. This special issue provides a view of the efforts carried out in this direction. Barlas introduces an optimization approach for reducing data communication and load imbalance in medical image matching on Grids. Binzenhofer et al. present a distributed and scalable algorithm to monitor a p2p network. Cesario and Talia discuss the use of data mining models and services on Grid systems for analysis of large data repositories. Danelutto et al. describe a performance model for component-based applications with stream communication semantics running on Grids. Danese et al. describe a FPGA-based coprocessor to accelerate double precision floating point operations in high-performance applications. Gross and Marquardt introduce a graphical editor providing abstractions from base technology for user-friendly configuration of Ubiquitous Computing environments. The papers collected here are selected extended versions of papers presented at PDP 2007, the Fifteenth Euromicro Conference on Parallel, Distributed and Network-based Processing, held in Naples, Italy, in February 2007. The conference was organized by the Institute for High-Performance Computing and Networking (ICAR) of the Italian National Research Council (CNR) in collaboration with the Second University of Naples, the University of Naples Parthenope and the University of Naples Federico II. We thank the editors of Scalable Computing: Practice and Experience for providing us the opportunity of publishing this issue, the authors for their contributions, and the referees for their precious help in selecting good-quality papers. Pasqua D'Ambra Institute for High-Performance Computing and Networking (ICAR), CNR Naples, Italy pasqua.dambra@cnr.it Daniela di Serafino Department of Mathematics, Second University of Naples Caserta, Italy daniela.diserafino@unina2.it Mario Rosario Guarracino Institute for High-Performance Computing and Networking (ICAR), CNR Naples, Italy mario.guarracino@cnr.it Francesca Perla Department of Statistics and Mathematics for Economic Research, University of Naples Parthenope Naples, Italy francesca.perla@uniparthenope.it

Despite the promising application of cloud computing within government organisations, determining the barriers to the successful implementation of cloud computing remains a major challenge. Often, government organisations face formidable barriers to fully adopting cloud computing functions. These barriers include organisational culture issues, a weak application of service-level agreements (SLAs), compliance issues, interoperability and integration issues, the lack of an organisational strategy, cost calculation methods, cloud service availability, and cloud data security and privacy, as well as insufficient trust in providers. Tackling these barriers while meeting the specifications of government cloud computing involves architectural requirements and mechanisms. In addition, the nature of cloud ecosystem operation and its alignment with appropriate strategies are known to be complex, also considering the growing desire for governance solutions. Although researchers and organisations have recognised cloud computing obstacles prior to the cloud implementation stage, fewer efforts have been made to investigate cloud barriers in-depth during and after cloud implementation projects or when introducing governance solutions. This might partly be attributable to inadequate enterprise requirements for addressing cloud barriers, the complexity of government cloud specifications, and the lack of involvement by cloud stakeholders, such as providers and consumers. Thus, the aim of this dissertation is to develop a governance method consisting of the generation and testing of architectural requirements to overcome dominant cloud barriers and improve cloud computing functionalities in the implementation stage. To achieve this, the roles of related cloud providers and consumers have been investigated. The study was guided by activities of The Open Group Architecture Framework (TOGAF) Architecture Development Method (ADM) to design related architectural requirements that would provide best practices for the development of the governance method. Using a sequential, exploratory mixed method, multiple qualitative case studies on the role of cloud providers were conducted to explore which and how architectural requirements are suitable and applicable for addressing the identified cloud barriers. Afterwards, a quantitative survey study was performed to examine and validate the findings from the qualitative phase and to discover the role of cloud consumers in tackling cloud barriers. The utilisation of dual perspectives, from cloud providers and consumers, to design and measure the suitability and applicability of the architectural requirements is a substantial theoretical contribution in the field of enterprise information systems and cloud governance. Both cloud providers and consumers in the selected research context balanced their roles in the composition of cloud ecosystem projects, reducing complexity and enabling cooperative solutions for handling cloud barriers with different levels of emphasis and prioritisation. The results of this thesis provide significant guidance in eliciting architectural requirements as well as in their successful contribution to addressing the 10 identified cloud barriers in the selected context. Seeking a cloud provider’s perspective through multiple case studies resulted in 24 confirmed, newly emerged architectural requirements and 48 sub-requirements for best practices to support Information Technology (IT) managers and practitioners during the implementation of government cloud projects. From the point of view of the cloud service consumer, statistical evidence showed that the architectural requirements proved to be relevant and applicable and resulted in the validation of only eight important cloud constructs with a scale of 36 architectural requirements. The results at the governance level also produced a clear method that can enhance the realisation of value when business/IT strategies and EA governance practices both take place in cloud projects. The governance method also consists of a set of architectural requirements to support managing and controlling cloud computing implementation projects with related stakeholders and change management initiatives. The architectural requirements have been modelled via the ArchiMate 3.0 modelling language as unique and beneficial contributions for the enhancement of enterprise architecture practices. This thesis thereby introduces a novel cloud governance method with clear mechanisms and practices to serve as crucial resources for related organisations, decision-makers, business practitioners and researchers.

A System Perspective on Business Models

The DREAM [1] software architecture model describes a reference class model and sequence diagrams, derived from use cases, that aid in integrating the different components for active distribution grids to applications. DREAM can be used in the commercial and grid operation application domains. It is designed to support the simulation (proof-of-concept) to the implementation stage (proof-of feasibility) of systems. The framework facilitates interoperability on the software and hardware level as well as from the communication technology level. The framework was designed from a use cases perspective. The major functionality implemented relates to flexible, heterarchic aggregation and coordination of devices involved in demand and supply of electricity. In the grid context, aim is to achieve a common objective, prioritize actions and operate on various timescales of grid operational and market functions. To that end, in the framework, monitoring data are handled and stored in a distributed fashion in order to directly steer or coordinate the operation of devices. These persistent data also allow handling forecasts and create interaction possibilities with actors or communities of actors on global and local markets and with operations in active distribution grids and customer energy management. A first implementation is now being built.