Changing User Requirements Research Articles

Which Factors Drive Rental Depreciation Rates for Office and Industrial Properties?

As new buildings are constructed in response to changes in technology or user requirements, the value of the existing stock will decline in relative terms. This is termed economic depreciation and it may be influenced by the age and quality of buildings, amount and timing of expenditure, and wider market and economic conditions. In this paper, we examine why individual assets experience different depreciation rates, applying panel regression techniques to 375 office and industrial assets in the United Kingdom. The results suggest that rental value depreciation rates reduce as buildings get older, while a composite measure of age and quality provides more explanation of depreciation than age alone. Furthermore, economic and local real estate market conditions are significant in explaining how depreciation rates change over time.

The verification of program relationships in the context of software cybernetics

Software Cybernetics is adopted by our method to improve reliability of software.A nested control system is established to manage the process of verification.A model is built from requirements to formalize expected behaviors of software.Internal relationships of program are abstracted gradually to construct a model.The feedback is represented by a form of intermediate code. Software cybernetics aims at improving the reliability of software by introducing the control theory into software engineering domain systematically. A key issue in software verification is to improve the reliability of software by inspecting whether the software can achieve its expected behaviors. In this paper, the thought of software cybernetics is applied in the process of verification to address this issue and a nested control system is established. The proposed method verifies functional requirements in a dynamic environment with constantly changing user requirements, in which the program serves as a controlled object, and the verification strategy determined by software behavioral model (SBM) serves as a controller. The main contribution of this paper includes: (1) SBM is established in software design phase, and a concern-based construction approach is proposed, which starts from obtaining the software expected functionality extracted from a requirement text; (2) Program abstract-relationship model (PARM) is constructed basing on a process of gradual abstract to be a controlled object; (3) Feedback in a form of intermediate code is generated in the process of verification. The proposed method is validated by our case study.

Self-Adaptively Auto-scaling for Mobile Cloud Applications

This paper proposes an approach to adapting distributed applications to changes in user requirements and resource availability. The key ideas behind the framework were dynamic deployment of components and dividing and merging components. The former enabled components to relocate themselves at new servers when provisioning the servers and remained servers when deprovisioning servers. The latter enabled the states of components to be divided and passed to other components and to be merged with other components according to user-defined functions. It was useful to adapt applications to elasticity in cloud computing. It is constructed as a middleware system for Java-based general-purposed software components. This paper describes the proposed approach and the design and implementation of the approach with applications.

A method of requirements change management for global software development

Context: Requirements change is an inevitable software development activity and can occur due to changes in user requirements, increased understanding of the stakeholders’ needs, customer organizational re-structure, and availability of new technologies. Timely management of these changes is vital to successful software development, which can be achieved through a rigorous requirements change management (RCM) process. RCM is not straight forward in collocated software development; and with the presences of geographical, social, cultural and temporal factors in Global Software Development (GSD), it makes RCM even more difficult for GSD. Existing RCM methods do not take into consideration of the GSD issues. Objective: In this paper, we present a method for managing requirements changes for GSD. Method: Our method consists of three stages: (i) an understanding of the changes required between different GSD sites is to be established; (ii) a change analysis is to be performed with respect to the development work, which might be either directly or indirectly affected by the changes; and (iii) a finalization of the changes will be made between GSD sites. Past researchers used student groups in a university environment to play the roles of stakeholders in experiments in GSD studies. We validate our method by applying it to a case study of an online shopping system, where the roles of stakeholders were played by a group of students. Results: The results showed that our method facilitates stakeholders to manage requirements changes for GSD better than the existing methods could. Conclusion: Managing changes in requirements at the right time improves the chance of developing a GSD project successfully by minimizing the risks associated with it.

A novel algorithm for link adaptation using fuzzy rule based system for wideband networking waveform of SDR

Adaptive and high speed communication with changing user requirements and environment conditions are the future needs of wireless networks. This is achieved by using the available resources optimally to increase the overall throughput by satisfying specific constraints. In this paper, a link adaptation algorithm for a hybrid multicode CDMA/adaptive TDMA based wideband networking waveform of SDR is proposed. The requirement of link adaptation increases when the transmissions are in the form of network packets. A low value of bit error rate can drastically increase packet error rate and thus packet re-transmissions, if the signal and protocol parameters are not dynamically changed according to the channel conditions and tolerable bit error rate. A constrained optimization problem has been formulated under the Quality of Service and throughput constraints. The optimization problem has been solved using fuzzy rule based system by dynamically changing the modulation technique and the number of multicodes assigned to each user. Simulation results are presented to demonstrate the effectiveness of the proposed algorithm in achieving better throughput by efficiently reducing the packet re-transmissions overhead.

Empirical Study of Agile Software Development Methodologies

In today's software industry, technological prowess and ever-evolving customer requirements have led to more complex software demands. Agile based software development is increasingly being adopted by the software practitioners as it assures early software development and high quality software products. Also, it offers responsiveness to changes in user requirements, providing for their quick absorption during software development. In this paper, we elaborate the significance, benefits and increasing adoption of Agile methodologies in context of today's complex and evolving software demands. The main objective of this paper is to conduct an empirical study into the choice among the most popular Agile methodologies, Scrum, Extreme Programming and Kanban. Further, this paper provides for a comparative analysis among various agile software development methodologies. Our survey results reveal higher adoption of Scrum based development in present-day software industry as compared to Extreme Programming and Kanban methodologies.

Dynamic Transaction Aware Web Service Selection

Web service composition, that recursively constructs a composite web service out of the existing services based on a business workflow has been acknowledged as a promising approach to meet the user demands, whenever a single service alone cannot fulfil the needs. In view of frequent failures in the internet environment where the composed service is executed, reliability of the composed service must be ensured. The reliability is determined by the behavioral or transactional properties of component services. The component services for each activity of the workflow must be selected based on their behavior so that their execution results in a consistent termination. Service selection must happen at run-time in order to consider the services available in a service registry at the time of execution. Towards this need, a dynamic transaction aware web service selection approach is proposed in this paper. Further, whenever user requirements change, a long running transaction must be interrupted and cancelled which is not addressed by any of the existing works. Hence, service cancellability property is proposed in this paper and incorporated in the dynamic selection approach. The overhead of the proposed run-time selection approach is assessed and the impact of increased services on its performance is also measured.

Early experiences with big data at an academic medical center.

Beth Israel Deaconess Medical Center (BIDMC), an academic health care institution affiliated with Harvard University, has been an early adopter of electronic applications since the 1970s. Various departments of the medical center and the physician practice groups affiliated with it have implemented electronic health records, filmless imaging, and networked medical devices to such an extent that data storage at BIDMC now amounts to three petabytes and continues to grow at a rate of 25 percent a year. Initially, the greatest technical challenge was the cost and complexity of data storage. However, today the major focus is on transforming raw data into information, knowledge, and wisdom. This article discusses the data growth, increasing importance of analytics, and changing user requirements that have shaped the management of big data at BIDMC.

Tx-FAITH

A key challenge in B2B and B2C applications involving dynamic composition of workflow activities is to ensure their reliable execution, in view of frequent failures in the internet environment where a composed service is executed. Existing approaches for transactional coordination of composite web services, consider forward and backward recovery alone, in order to maintain consistency in the case of failures. However, while achieving reliable execution, service cancellability is important due to the predominance of long running processes in business applications and frequently changing user requirements and business policies. If the execution of a long running process is not cancelled in the case of a changed requirement, the completion of the process results in wastage of resources and the outcome may no longer be useful. Hence, a transactional coordination framework named as Tx-FAITH is proposed to handle the cancellation recovery under the external interruption and cancellation of transactions. Tx-FAITH considers hierarchically composed web services whose components are recursively nested to form a composition and adapts a coordination approach based on context information. The proposed coordination and recovery approach when tested with 200 simultaneous users and with a database size of 0.35 million records, incurs only 10 seconds to process a request.

Applicability of Lehman Laws on Open Source Evolution: A Case study

Software evolution is an essential characteristic of real world software ,as the user requirements changes, software needs to change otherwise it becomes less useful. In order to be used for a longer time period, software needs to evolve. Software evolution can be a result of software maintenance. An effort is made to find the applicability of Lehman Laws on different releases of two software developed in C++ using objectoriented metrics In this paper, a study has been conducted on 10 versions of Graphics Layout Engine and Flight Gear Simulator evolved over the period of eight years.. The laws of continuous change, growth and complexity are found applicable according to the data collected. General Terms Validation

Test suite reduction methods that decrease regression testing costs by identifying irreplaceable tests

ContextIn software development and maintenance, a software system may frequently be updated to meet rapidly changing user requirements. New test cases will be designed to ensure the correctness of new or modified functions, thus gradually increasing the test suite’s size. Test suite reduction techniques aim to decrease the cost of regression testing by removing the redundant test cases from the test suite and then obtaining a representative set of test cases that still yield a high level of code coverage. ObjectiveMost of the existing reduction algorithms focus on decreasing the test suite’s size. Yet, the differences in execution costs among test cases are usually significant and it may take a lot of execution time to run a test suite consisting of a few long-running test cases. This paper presents and empirically evaluates cost-aware algorithms that can produce the representative sets with lower execution costs. MethodWe first use a cost-aware test case metric, called Irreplaceability, and its enhanced version, called EIrreplaceability, to evaluate the possibility that each test case can be replaced by others during test suite reduction. Furthermore, we construct a cost-aware framework that incorporates the concept of test irreplaceability into some well-known test suite reduction algorithms. ResultsThe effectiveness of the cost-aware framework is evaluated via the subject programs and test suites collected from the Software-artifact Infrastructure Repository — frequently chosen benchmarks for experimentally evaluating test suite reduction methods. The empirical results reveal that the presented algorithms produce representative sets that normally incur a low cost to yield a high level of test coverage. ConclusionThe presented techniques indeed enhance the capability of the traditional reduction algorithms to reduce the execution cost of a test suite. Especially for the additional Greedy algorithm, the presented techniques decrease the costs of the representative sets by 8.10–46.57%.

Which Factors Drive Rental Depreciation Rates for Office and Industrial Properties?

The life cycle of individual commercial and industrial buildings has a major impact on the form and functioning of towns and cities and is an important consideration for building owners and occupiers. During this life cycle, buildings may experience physical deterioration and obsolescence, the latter driven by changes in technology or user requirements. If new cohorts of buildings are constructed in response to such changes, the functionality and value of the existing stock will decline in relative terms. This decline in value is termed economic depreciation and the rate of such decline may be influenced by factors such as the design and quality of existing buildings, the amount and timing of expenditure on such buildings, and wider market and economic conditions. Many previous studies have measured depreciation and assessed its pattern with respect to age, producing depreciation rates that inform the inputs used by building owners in cash flow modelling exercises. This study goes beyond measurement of depreciation and seeks to explain why individual assets experience different depreciation rates. It does this by applying panel regression techniques to a dataset of rental depreciation rates for 375 UK office and industrial buildings observed over the period 1994 to 2009. Results suggest that rental depreciation rates reduce as a building gets older, while a composite measure of age and quality provides more explanation of depreciation than age alone. Furthermore, variables representing the state of the economy and local real estate market are significant in explaining how rental depreciation rates change over time.

CRISTAL: A practical study in designing systems to cope with change

Software engineers frequently face the challenge of developing systems whose requirements are likely to change in order to adapt to organizational reconfigurations or other external pressures. Evolving requirements present difficulties, especially in environments in which business agility demands shorter development times and responsive prototyping. This paper uses a study from CERN in Geneva to address these research questions by employing a ‘description-driven’ approach that is responsive to changes in user requirements and that facilitates dynamic system reconfiguration. The study describes how handling descriptions of objects in practice alongside their instances (making the objects self-describing) can mediate the effects of evolving user requirements on system development. This paper reports on and draws lessons from the practical use of a description-driven system over time. It also identifies lessons that can be learned from adopting such a self-describing description-driven approach in future software development.

A Semantic-Driven Knowledge Representation Model for the Materials Engineering Application

A Materials Engineering Application (MEA) has been presented as a solution for the problems of materials design, solutions simulation, production and processing, and service evaluation. Large amounts of data are generated in the MEA distributed and heterogeneous environment. As the demand for intelligent engineering information applications increases, the challenge is to effectively organize these complex data and provide timely and accurate on-demand services. In this paper, based on the supporting environment of Open Cloud Services Architecture (OCSA) and Virtual DataSpace (VDS), a new semantic-driven knowledge representation model for MEA information is proposed. Faced with the MEA constantly changing user requirements, this model elaborates the semantic representation of data, services and their relationships to support the construction of domain knowledge ontology. Then, based on the ontology modeling in VDS, the semantic representations of association mapping, rule-based reasoning, and evolution tracking are analyzed to support MEA knowledge acquisition. Finally, an application example of knowledge representation in the field of materials engineering is given to illustrate the proposed model, and some experimental comparisons are discussed for evaluating and verifying the effectiveness of this method.

A New Approach to Building Design Modularization

In this research a graph-based methodology has been developed to support modular building design. A graph-theoretic algorithm is used to decompose the design into modules that facilitate the future replacement of building components, allowing buildings to be more easily adapted to changing user requirements. The future flexibility of the building is increased by decomposing it into custom-designed modules, containing adjacent components that currently belong to different systems, but need to be replaced at the same time in the future. The reduction and standardization of the interfaces between the modules can also reduce the interdependencies between the activities for installing the building components, which are currently carried out by different subcontractors. It is shown that this approach to modularization increases the flexibility of the design, as well as reducing expected time overruns during project execution. Such overruns normally occur due to the knock-on effects of a delay in one construction activity on other interrelated activities that are carried out by different subcontractors. The methodology is demonstrated through a case study of a residential housing unit.

A Traceability Based Approach for Model Synchronization

In developing software systems, evolution is an inevitable aspect which affects artefacts in the whole life-cycle. Changes may be caused by changing user requirements or be induced by changes in implementation technologies. In Model Driven Engineering, the model is mainly the most artefact concerned by modifications and it's evolution causes changes in all the models obtained as products in the transformation chain. As a consequence, the impacted models have to be updated for preserving their coherency. This article deals with the coevolution problem by proposing an approach to ensure the co-evolution of artefacts after model changes.

Information Systems and Actor-Network Theory Analysis

Evidently, based on studies which have been conducted over the years, there exist lots more complexity than technical in the development and implementation of information systems in organisations. The complex issues are socio-technical in nature, which require a refresh examination, from social context, if different results are to be achieved. Some of the complexities which are encountered include operational issues, environmental trends, processes flow, communicative scheme, and actors’ relationship. The unpredictable nature of business and rapidly changing user requirements makes it even more difficult to develop and implement systems within budget and timeframe. Other challenges are within the social context, such as politics and culture affiliations. Through the lens of Actor-Network Theory (ANT) understanding of the social context of how information systems are developed and implemented is gained. Although ANT has been employed in many studies, it is of significant important to establishes and clarifies the factors, from the social perspective, which influences the development and implementation of information systems in organisations.

AO4AADL: Aspect oriented extension for AADL

Abstract Managing embedded system complexity and scalability is one of the most important problems in software development. To better address this problem, it is very recommended to have an abstraction level high enough to model such systems. Architectural description languages (ADLs) intend to model complex systems and manage their structure at a high abstraction level. Traditional ADLs do not normally provide appropriate formalisms to separate any kind of crosscutting concerns. This frequently results in poor descriptions of the software architectures and a tedious adaptation to constantly changing user requirements and specifications. AOSD (Aspect Oriented Software Development) deals with these problems by considering crosscutting concerns in software development. The effectiveness of considering an aspect-oriented architectural design appears when aspect concepts are taken into account early in the software’s life-cycle. In this paper, we propose a new aspect language called AO4AADL that adequately manipulates aspect oriented concepts at architecture level in order to master complexity and ensure scalability. The abstract nature of our proposed language allows the generation of aspect code for several programming languages and platforms.

Refactoring android Java code for on-demand computation offloading

Computation offloading is a promising way to improve the performance as well as reducing the battery power consumption of a smartphone application by executing some parts of the application on a remote server. Supporting such capability is not easy for smartphone application developers due to (1) correctness: some code, e.g., that for GPS, gravity, and other sensors, can run only on the smartphone so that developers have to identify which parts of the application cannot be offloaded; (2) effectiveness: the reduced execution time must be greater than the network delay caused by computation offloading so that developers need to calculate which parts are worth offloading; (3) adaptability: smartphone applications often face changes of user requirements and runtime environments so that developers need to implement the adaptation on offloading. More importantly, considering the large number of today's smartphone applications, solutions applicable for legacy applications will be much more valuable. In this paper, we present a tool, named DPartner, that automatically refactors Android applications to be the ones with computation offloading capability. For a given Android application, DPartner first analyzes its bytecode for discovering the parts worth offloading, then rewrites the bytecode to implement a special program structure supporting on-demand offloading, and finally generates two artifacts to be deployed onto an Android phone and the server, respectively. We evaluated DPartner on three real-world Android applications, demonstrating the reduction of execution time by 46%-97% and battery power consumption by 27%-83%.

Efficient adaptation of XML data using a conceptual model

One of the prominent characteristics of XML applications is their dynamic nature. Changes in user requirements cause changes in schemas used in the systems and changes in the schemas subsequently make existing documents invalid. In this work, we study two tightly coupled problems--schema evolution and document adaptation. The presented approach extends an existing conceptual model for evolution of XML applications towards document adaptation, by introducing a formal framework for detecting changes between two versions of a schema. From the detected changes it is possible to create a script that transforms documents valid against the old version of the schema to documents valid against its new version.