A Systematic Classification and Analysis of NFRs

The main agenda of Requirements Engineering (RE) is the development of tools, techniques and languages for the elicitation, specification, negotiation, and validation of software requirements. However, this development has traditionally been focused on functional requirements (FRs), rather than non-functional requirements (NFRs). Consequently, NFR approaches developed over the years have been fragmental and there is a lack of clear understanding of the positions of these approaches in the RE process. This paper provides a systematic classification and analysis of 89 NFR approaches

On the Resummation of Subleading Logarithms in the Transverse Momentum Distribution of Vector Bosons Produced at Hadron Colliders

The perturbation series for electroweak vector boson production at small transverse momentum is dominated by large double logarithms at each order in perturbation theory. An accurate theoretical prediction therefore requires a resummation of these logarithms. This can be performed either directly in transverse momentum space or in impact parameter (Fourier transform) space. While both approaches resum the same leading double logarithms, the subleading logarithms are, in general, treated differently. We comment on two recent approaches to this problem, emphasising the particular subleading logarithms resummed in each case and the numerical differences in the cross sections which result.Comment: 13 (Latex) pages, including 5 embedded figures, uses epsfig.st

Scope Management of Non-Functional Requirements

In order to meet commitments in software projects, a realistic assessment must be made of project scope. Such an assessment relies on the availability of knowledge on the user-defined project requirements and their effort estimates and priorities, as well as their risk. This knowledge enables analysts, managers and software engineers to identify the most significant requirements from the list of requirements initially defined by the user. In practice, this scope assessment is applied to the Functional Requirements (FRs) provided by users who are unaware of, or ignore, the Non-Functional Requirements (NFRs). This paper presents ongoing research which aims at managing NFRs during the software development process. Establishing the relative priority of each NFR, and obtaining a rough estimate of the effort and risk associated with it, is integral to the software development process and to resource management. Our work extends the taxonomy of the NFR framework by integrating the concept of the "hardgoal". A functional size measure of NFRs is applied to facilitate the effort estimation process. The functional size measurement method we have chosen is COSMICFFP, which is theoretically sound and the de facto standard in the software industry

Stochastic information technology modelling for business processes

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Business Processes (BP) and Information Technology (IT) are two areas that work very closely in helping organisations to keep or retain competitive advantage. Therefore, design in these areas should consider the advantages provided by, and the limitations that each of these domains imposes on each other. BP design tries to ensure that IT specifications are considered during the design of BP. Similarly, Information Systems (IS) design attempts to capture organisational needs, known as IS functional and Non-Functional Requirements (NFR), in order to meet the organisational goals. Despite this, BP and IT modelling techniques barely depict the way IT may affect BP performance or vice versa. For example, Business Process Simulation (BPS) is one of the modelling techniques that has been increasingly used to support process design. The performance measurements obtained from BPS models, though, are obtained considering only organisational issues, and thus cannot be used to assess the impact that IT may have on process performance. Similarly, IT modelling techniques do not provide IS performance measurements, and hence cannot depict the way IS may improve BP performance. The relationship between BP and IT can be alternatively described in terms of the relationships between BP, IS and Computer Networks (CN). By looking at the parameters that govern these relationships a simulation framework was developed, namely ASSESS-IT, that develops simulation models that provide performance measurements of BP, IS and CN, and thus can reflect the impact that IT (IS and CN) may have on BP performance. This research uses a case study to test the proposed framework (theory testing), to understand the way BP, IS, and CN domains interact (discovery), and to propose alternative theories to solve the problems found (theory building). The experimentation with the ASSESS-IT framework suggests that in order to portray the impact that IT may have on BP, analysts in these domains should first identify those performance specifications that describe how well the IS delivers its functionality (also known as non-functional requirements). It was found that when the IS does not depend on determined response time, the relationships between BP, IS and CN can be assessed using only the relationship between BP and IS. An alternative simulation framework, namely BPISS, is proposed to produce BPS models that provide performance measurements of BP and IS. Thus, BP and IT analysts can investigate the impact that a given IS design may have on BP performance, and identify a better BP and IS solution.CONACYT, Mexic

Addressing aspect interactions in an industrial setting: experiences, problems and solutions

Aspect oriented programming (AOP) introduces new and powerful modularization constructs. The aspect module is used to encapsulate crosscutting concerns, which otherwise would remain tangled and scattered. The idea of encapsulating crosscutting concerns rapidly expanded to earlier phases in the development cycle, including requirement analysis (aspect oriented requirement engineering, AORE) and design (aspect oriented modeling, AOM). The overall application of aspect orientation concepts is known as aspect oriented software development (AOSD). AOP is not yet a mainstream practice. Particularly AOSD is still in its early stages. This is reflected in the lack of reports of full development cycles using aspect oriented approaches, especially using industrial case studies. Furthermore, the power of aspects comes at the price of new challenges, one of them is that systems built using aspects are more difficult to understand. The crosscutting nature of aspects allows them to alter the behavior of many other modules. As a result, aspects may interact in unintended and unanticipated ways. This problem is known as aspect interactions. In this work we deal with the aspect interaction problem in the context of an industrial domain: slots machines. We perform a complete development cycle of the slot machine software. This is, to the best of our knowledge, the first complete industrial case of study of aspect orientation. Through this experience we discovered the limitations with regard to aspect interactions, of some emblematic aspect oriented approaches for requirement engineering, design and implementation. The contribution of this work is threefold. Firstly, we contribute with the evaluation and extensions to some of AORE and AOM approaches, in order to provide explicit support for aspect interactions in requirement analysis and design phases. We also evaluate the implementation of interactions using a static and a dynamic AOP language, and propose an AspectJ extension that copes with aspect interactions. Secondly, this work is the first report of a complete aspect oriented development cycle of an industrial case study. Thirdly, this work provides a complex case study that presents several business logic crosscutting concerns, which in turn exhibit numerous aspect interactions, that serves as a challenging test bed for upcoming AOSD approaches.Facultad de Informátic

Thermodynamics and kinetics of hydrophobic organic compound sorption in natural sorbents and quantification of black carbon by electron microscopy

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (v. 3, p.1198-1258).The sorption behaviors of hydrophobic organic compounds (HOCs) in sediments were investigated using pyrene. Native pyrene desorbed slowly, taking from weeks to months to equilibrate. The end-point data suggested that, at nanogram-pyrene-per-liter porewater levels, sorption was much stronger than conventionally expected. The non-linearity of the isotherm may indicate physical occlusion of native sorbate and/or sorption onto micropore surfaces of char/charcoal. Between 30-70% of the native pyrene may be occluded. Conceptual pictures for both hypotheses were presented with supportive evidence from experiments and literature. Analysis of experimental and literature data suggested logKoc (organic-carbon normalized partition coefficient) and logKBC (black-carbon normalized partition coefficient) values were fairly constant across different geosorbents (around 4.5-5.7 and 5.6-6.3, respectively), while the non-linearity exponent varied substantially. This may explain the orders of magnitude scatter in logKoc's and logKBC's reported in recent reviews. An a priori non-linear numerical model based on Intra-particle Porewater Diffusion (IPD) was constructed and successfully predicted the desorption kinetics of native pyrene. Fitted kinetic parameters correlated with system and sorbate/sorbent properties. This suggested the empirical approach can be replaced by the a priori model and the diverse HOC desorption rates in the literature can be reconciled if relevant physicochemical properties are known. The regional fate of pyrene in Boston Harbor was evaluated with a box model using derived kinetic and equilibrium properties. Realistic predictions can be obtained when assuming pseudo steady state conditions, but not equilibrium partitioning, for the bed sediment and the water column. Furthermore, model results and literature evidence suggested that sediment resuspension may be a significant mobilization mechanism for sedimentary HOCs in estuaries and harbors. A new BC quantification method based on energy dispersive X-ray spectroscopy (EDX) was developed. The method identified/quantified Organic Carbon (OC) or Black Carbon (BC) by analyzing the elemental ratios of C, N, and 0 of the sample. Agreeable OC/BC estimates on a variety of carbonaceous materials were obtained using the method. The good analytical potential of the method warranted further exploration and methodological refinement. This study has great implications for the sequestration and bioavailability of HOCs in the environment.by Dave T. F. Kuo.Ph.D