Architectural Design Decisions Research Articles

MULTI ATTRIBUTE ARCHITECTURE DESIGN DECISION FOR CORE ASSET DERIVATION

Software Product Line (SPL) is an effective approach in software reuse in which core assets can be shared among the members of the product line with an explicit treatment of variability. Core assets, which are developed for reuse in domain engineering, are selected for product specific derivation in application engineering. Decision making support during product derivation is crucial to assist in making multiple decisions during product specific derivation. Multiple decisions are to be resolved at the architectural level as well as the detailed design level, address the need for assisting the decision making process during core asset derivation. Architectural level decision making is based on imprecise, uncertain and subjective nature of stakeholder for making architectural selection based on non- functional requirements (NFR). Furthermore, detail design level involves the selection of suitable features which have the rationale behind each decision. The rationale for the selection, if not documented properly, will also result in loss of tacit knowledge. Therefore, a multi-attribute architecture design decision technique is proposed to overcome the above mentioned problem. The technique combines Fuzzy Analytical Hierarchy Process (FAHP) with lightweight architecture design decision documentation to support the decision making during core asset derivation. We demonstrate our approach using the case study of Autonomous Mobile Robot (AMR). The case study implementation shows showed that the proposed technique supports software engineer in the process of decision making at the architecture and detail design levels.

Evaluating Architectural Design Decision Paradigms in Global Software Development

Global software development (GSD) is considered as the coordinated activities of software development that are geographically and temporally distributed. The management of architectural knowledge, specifically, architectural design decisions (ADDs), becomes important in GSD due to the geographical, temporal, and cultural challenges in global environments. Based on our previous work on ADD management in localized software development, we present five ADD paradigms for GSD projects with different organizational structures. We also investigate the benefits and the challenges of these ADD paradigms by conducting an evaluation of the paradigms using extensive archived semi-structured interview data from industrial GSD projects. We aim to provide a fundamental framework for managing ADD documentation and evolution in GSD, as well as offer useful insights into managing architectural knowledge in a global setting.

Two controlled experiments on model-based architectural decision making

ContextIn recent years, architectural design decisions are becoming more and more common for documenting software architectures. Rather than describing the structure of software systems, architectural decisions capture the design rationale and – often reusable – architectural knowledge. Many approaches and tools have been proposed in the literature to support architectural decision making and documentation (for instance, based on models, ontologies, or templates). In this context, the capturing, organization, and effective reuse of architectural knowledge has gained a lot of attention. ObjectiveHowever, there is little empirical evidence about the supportive effect of reusable architectural knowledge on the effectiveness and efficiency of architectural decision making. MethodTo investigate these aspects, we conducted two separate controlled experiments with software architecture students in which we tested the supportive effect of reusable decision models in decision making and documentation. ResultsOur results show that the use of reusable decision models can significantly increase both the efficiency and the effectiveness of novice architects. ConclusionWe can report, that our findings are in line with similar studies and support the claims regarding reusable architectural design decisions in principle.

Automatic enforcement of constraints in real-time collaborative architectural decision making

Making and documenting architectural design decisions becomes increasingly important in the process of software architecting. However, the remoteness of different decision stakeholders, ranging from local distribution in an office environment to globally distributed teams, as well as the different domain knowledge, expertise and responsibilities of the stakeholders hinder effective and efficient collaboration. Existing tools and methods for collaborative architectural decision making focus mainly on sharing and reusing of knowledge, making trade-offs, and achieving consensus, but do not consider the various stakeholders’ decision making constraints due to their roles in the development process. To address this problem, we propose a meta-model for a set of decision making constraints, with precisely defined semantics, as well as a collaborative architectural decision making approach based on this meta-model. We also present tool support, called CoCoADvISE, which automatically enforces the constraints at runtime. The evaluation of this tool in a controlled experiment with 48 participants shows that our approach, besides preventing constraint violations, significantly increases both the time and effort related efficiency, as well as the effectiveness of users in collaborative decision making.

Harmonizing architectural decisions with component view models using reusable architectural knowledge transformations and constraints

Architectural design decisions (ADDs) have been used in recent years for capturing design rationale and documenting architectural knowledge (AK). However, various architectural design views still provide the most common means for describing and communicating architectural design. The evolution of software systems requires that both ADDs and architectural design views are documented and maintained, which is a tedious and time-consuming task in the long run. Also, in lack of a systematic and automated support for bridging between ADDs and architectural design views, decisions and designs tend to become inconsistent over time. In our proposal, we introduce a reusable AK transformation language for supporting the automated transformation of reusable AK knowledge to component-and-connector models, the architectural design view used most commonly today. In addition, reusable consistency checking rules verify the consistency between decisions and designs. We evaluate our approach in an industrial case study and show that it offers high reusability, provides automation, and can, in principle, deal with large numbers of recurring decisions.

The construction and implementation of a multichannel loudspeaker array for accurate spatial reproduction of sound fields

The spatial distribution of sound has a strong impact upon a listener’s overall impression of a room and must be reproduced accurately for auralization. In concert hall acoustics, directionally independent metrics such as reverberation time and clarity index simply do not predict this impression. Late lateral energy level, lateral energy fraction, and the interaural correlation coefficient are measures of spatial impression, but more work is needed before we fully understand how the directional distribution of sound should influence architectural design decisions. A three-dimensional array of 28 loudspeakers and two subwoofers has been constructed in a hemi-anechoic chamber at PSU, allowing for accurate reproduction of sound fields. For the array, closed-box loudspeakers were built and digitally equalized to ensure a flat frequency response. With this facility, subjective studies investigating spatial sound in concert halls can be conducted using measured sound fields and perceptually motivated auralizations, not tied to a physical room. Such a facility is instrumental in understanding and communicating subtle differences in sound fields to listeners, whether they be musicians, architects, or clients. The flexibility and versatility of this system will facilitate room acoustics research at Penn State for years to come. [Work supported by NSF Award 1302741.]

How product owner teams scale agile methods to large distributed enterprises

Software development teams in large scale offshore enterprise development programmes are often under intense pressure to deliver high quality software within challenging time contraints. Project failures can attract adverse publicity and damage corporate reputations. Agile methods have been advocated to reduce project risks, improving both productivity and product quality. This article uses practitioner descriptions of agile method tailoring to explore large scale offshore enterprise development programmes with a focus on product owner role tailoring, where the product owner identifies and prioritises customer requirements. In globalised projects, the product owner must reconcile competing business interests, whilst generating and then prioritising large numbers of requirements for numerous development teams. The study comprises eight international companies, based in London, Bangalore and Delhi. Interviews with 46 practitioners were conducted between February 2010 and May 2012. Grounded theory was used to identify that product owners form into teams. The main contribution of this research is to describe the nine product owner team functions identified: groom, prioritiser, release master, technical architect, governor, communicator, traveller, intermediary and risk assessor. These product owner functions arbitrate between conflicting customer requirements, approve release schedules, disseminate architectural design decisions, provide technical governance and propogate information across teams. The functions identified in this research are mapped to a scrum of scrums process, and a taxonomy of the functions shows how focusing on either decision-making or information dissemination in each helps to tailor agile methods to large scale offshore enterprise development programmes.

An Ontology-based Approach For Software Architectural Knowledge Management

Over the past few years, a large number of models, ontologies and tools have been proposed to capture, share and the management of architectural knowledge (AK) and particularly architectural design decisions (ADD) as an important part of AK of a software-intensive system. However, the growing tendency in Globalization of Software Development sets the stage for new challenges in the management of AK in a geographically distributed context in which it seems the existing AK models and tools are no longer sufficient for such setting. In this paper we develop an ontology-based approach to manage AK in order to partly mitigate the deficiencies of existing AK approaches in a distributed software devotement.

The Stratosphere platform for big data analytics

We present Stratosphere, an open-source software stack for parallel data analysis. Stratosphere brings together a unique set of features that allow the expressive, easy, and efficient programming of analytical applications at very large scale. Stratosphere's features include "in situ" data processing, a declarative query language, treatment of user-defined functions as first-class citizens, automatic program parallelization and optimization, support for iterative programs, and a scalable and efficient execution engine. Stratosphere covers a variety of "Big Data" use cases, such as data warehousing, information extraction and integration, data cleansing, graph analysis, and statistical analysis applications. In this paper, we present the overall system architecture design decisions, introduce Stratosphere through example queries, and then dive into the internal workings of the system's components that relate to extensibility, programming model, optimization, and query execution. We experimentally compare Stratosphere against popular open-source alternatives, and we conclude with a research outlook for the next years.

A systematic review of software architecture visualization techniques

ContextGiven the increased interest in using visualization techniques (VTs) to help communicate and understand software architecture (SA) of large scale complex systems, several VTs and tools have been reported to represent architectural elements (such as architecture design, architectural patterns, and architectural design decisions). However, there is no attempt to systematically review and classify the VTs and associated tools reported for SA, and how they have been assessed and applied. ObjectiveThis work aimed at systematically reviewing the literature on software architecture visualization to develop a classification of VTs in SA, analyze the level of reported evidence and the use of different VTs for representing SA in different application domains, and identify the gaps for future research in the area. MethodWe used systematic literature review (SLR) method of the evidence-based software engineering (EBSE) for reviewing the literature on VTs for SA. We used both manual and automatic search strategies for searching the relevant papers published between 1 February 1999 and 1 July 2011. ResultsWe selected 53 papers from the initially retrieved 23,056 articles for data extraction, analysis, and synthesis based on pre-defined inclusion and exclusion criteria. The results from the data analysis enabled us to classify the identified VTs into four types based on the usage popularity: graph-based, notation-based, matrix-based, and metaphor-based VTs. The VTs in SA are mostly used for architecture recovery and architectural evolution activities. We have also identified ten purposes of using VTs in SA. Our results also revealed that VTs in SA have been applied to a wide range of application domains, among which “graphics software” and “distributed system” have received the most attention. ConclusionSA visualization has gained significant importance in understanding and evolving software-intensive systems. However, only a few VTs have been employed in industrial practice. This review has enabled us to identify the following areas for further research and improvement: (i) it is necessary to perform more research on applying visualization techniques in architectural analysis, architectural synthesis, architectural implementation, and architecture reuse activities; (ii) it is essential to pay more attention to use more objective evaluation methods (e.g., controlled experiment) for providing more convincing evidence to support the promised benefits of using VTs in SA; (iii) it is important to conduct industrial surveys for investigating how software architecture practitioners actually employ VTs in architecting process and what are the issues that hinder and prevent them from adopting VTs in SA.

A General Evaluation on Double Skin Facades

This study examines the literature of double-skin facade systems over the last decade, and, with the help of tables and graphics, investigates their advantages and disadvantages. Moreover, a detailed comparison is made between double skin facade systems. The results of the study show that the greatest advantage (95%) of double skin facade systems is their provision of natural ventilation. Other advantages are highlighted according to their percentage as follows: An increase in interaction between user and environment because of the high proportion of transparency, support of heat and sound insulation, reduction in heat transmission and solar heat gain coefficient, an increase in thermal comfort, allowance of solar control elements between the two facade spaces, and protection of these elements from external environment conditions. The most commonly accepted disadvantage (72%) is overheating in the air space of the two facades. Other disadvantages are highlighted according to their percentage as follows: Problems related to a decrease in the amount of daylight entering the building, high investment costs, additional maintenance and repair costs, fire, and acoustic problems. In our country, architectural design decisions related to overheating must be taken so as to provide a positive contribution to energy performance and the applicability of these systems.

Sustainable Architectural Design Decisions

Software architects must sustain design decisions to endure throughout software evolution. Several criteria can help them assess decisions' sustainability. In addition, industry and research projects have applied different techniques to make architectural design decisions sustainable; their examples offer solutions and lessons learned.

Cloud Workload Characterization

This paper describes various computer system workloads and relates them to their underlying resource utilization. Specifically, the paper concentrates on Cloud workload characterization based upon issues, capabilities, and technologies surrounding the categories from the multiple points of view of the various players involved in Cloud Computing. The relationship is established between the categories and key limiting underlying technologies, and the dynamic and measurable low-level metrics and measurements that are used to detect and reduce resource contention, and identify category changes during run-time. Research questions are posed on dynamic low-level measurements and a usage case example with high performance computing (HPC) clusters. The Cloud workload categories can provide a basis for common communication for various viewpoints from players, including facility managers, Cloud IT or service providers, Cloud users, consumers, IT managers, and hardware vendors. This common communication tool will facilitate better service-level agreements (SLAs), capital purchase decisions, and future computer architecture design-decisions.

Effective Architectural Design Decisions in Double Skin Facades

Effective Architectural Design Decisions in Double Skin Facades

Breaking down the requirements: Reliability in remote handling software

Software requirements have an important role in achieving reliability for operational systems like remote handling: requirements are the basis for architectural design decisions and also the main cause of defects in high quality software. We analyze related recommendations and requirements given in software safety standards, handbooks etc. and apply them to remote handling control systems, which typically have safety-critical functionality, but are not actual safety-systems⿿for example the safety-systems in ITER will be hardware-based.Based on the analysis, we develop a set of generic recommendations for control system software requirements, including quality attributes, software fault tolerance, and safety and as an example we analyze ITER remote handling system software requirements to identify and present dependability requirements in a useful manner. Based on the analysis, we divide a high-level control system into safety-critical and non-safety-critical subsystems, and give examples of requirements that support building a dependable system.

Sinfonia inacabada da habitação coletiva: lições a partir do PREVI para uma arquitetura de possibilidades

Os esforços pela busca de uma maior sustentabilidade nas cidades inspiram os projetos de habitação coletiva como importante perspectiva para devolver caraterística mais humanizadora para o habitar urbano. Este trabalho discute um recorte específico no sentido de intermediar e apoiar as decisões estruturantes do projeto arquitetônico e urbanístico que considere a possibilidade de modificações como parte do processo de projeto e do programa habitacional. O trabalho tem por objetivo obter derivações conceituais para análise, reflexão e realização projetual relacionadas à capacidade adaptativa da habitação como possível agregadora de valor multidimensional para os moradores. A partir dos fundamentos teórico-conceituais relacionados, buscou-se identificar exemplar de habitação coletiva representativo para análise, selecionando-se o Proyecto Experimental de Vivienda-PREVI em Lima, Peru, pela sua importância e impacto. O estudo evidenciou alguns dos enfoques e suscitou outros conceitos relevantes para o processo de projeto. Apresenta-se uma análise do estudo de caso e o aprimoramento da base teóricoconceitual de potencial humanizador e de sustentabilidade socioambiental. O estudo permite o refinamento conceitual vinculado ao projeto da habitação coletiva com vistas à geração de valor multidimensional para o habitar humanizador e mais sustentável.

Knowledge representation of the software architecture design process based on situation calculus

AbstractSoftware architecture design is an interactive, complex, decision‐making process. Such a design process involves the exploration, evaluation, and composition of design alternatives. Increasingly, new computer‐aided tools are available to help designers in these complex activities. However, these tools do not know how design is actually done, in other words, by means of which design activities the final artefact was obtained. In fact, the architectural design knowledge exclusively rests in the mind of designers, and there is an urgent need to move it, as much as possible, to a computer‐supported environment that enables the capture of this type of knowledge. This contribution addresses this need by introducing a model for capturing how products under development are generated and transformed along the software architecture design process. The proposed model follows an operational perspective, where architectural design decisions are modelled by means of sequences of operations that are applied on the design products. Situation calculus is used to formally express the existence of an object in a given state of a design process. In addition, this formalism allows us expressing without ambiguities when an operation can be performed in a specific state of the design process.

Special Questions and techniques

Jeopardy!™ questions represent a wide variety of question types. The vast majority are Standard Jeopardy! Questions, where the question contains one or more assertions about some unnamed entity or concept, and the task is to identify the described entity or concept. This style of question is a representative of a wide range of common question-answering tasks, and the bulk of the IBM Watsoni system is focused on solving this problem. A small percentage of Jeopardy! questions require a specialized procedure to derive an answer or some derived assertion about the answer. We call any question that requires such a specialized computational procedure, selected on the basis of a unique classification of the question, a Special Jeopardy! Question. Although Special Questions per se are typically less relevant in broader question-answering applications, they are an important class of question to address in the Jeopardy! context. Moreover, the design of our Special Question solving procedures motivated architectural design decisions that are applicable to general open-domain question-answering systems. We explore these rarer classes of questions here and describe and evaluate the techniques that we developed to solve these questions.

Modeling customer-centric value of system architecture investments

System architecture investments aim at improving the quality of the system in alignment with (current and future) business goals. While the costs of architecture changes are routinely calculated, identifying benefits of architecture changes and translating them to a monetary value has been a challenge in practice. Currently, architecture value estimation is largely based on cost-savings or on risk mitigation, without much reliance on potential customer benefits. This article reports on our experience in modeling the customer value and evaluating its potential use in choosing between different system architectures in two case studies conducted in an organization developing healthcare systems. To model the customer value, we exploit best practices in management and marketing. Management tools, in particular strategy maps and balanced scorecards, are used to identify customer-centric benefits caused by architecture design decisions. Furthermore, two marketing concepts, customer value-in-use and customer segments, are adopted to quantify the value of architecture changes for a single customer and multiple customers, respectively. The paper shows that using the customer value in addition to the existing value indicators in the organization has several advantages but also calls for future improvements to be adopted in practice.

The supportive effect of patterns in architecture decision recovery— A controlled experiment

The documentation of software architectural design decisions is important to help people understand the system and the rationale behind architectural solutions. In practice, the documentation of such decisions is regularly done after the fact, or skipped completely. To support software maintenance and evolution, the decisions have to be recovered and described. This is often hindered by the fact that the original architects are not available any more, or they do not completely remember the reasons for making the decisions. Additionally, the whole process is very expensive. In this paper, we hypothesize that architecture decision recovery can be more efficient by focusing on recovering decisions related to applying architecture patterns. To test this hypothesis, we designed a controlled experiment that was conducted to analyze the impact of architecture patterns on the quality and quantity of architecture decisions recovered after the fact. We are able to provide statistical evidence that a focus on patterns significantly increases the quality of decisions, while no conclusive evidence concerning the quantity of decisions was found.