Guest Editors' Introduction: Cooperative and Human Aspects of Software Engineering

Software is developed by people, used by people, and supports interaction among people. As such, human characteristics and cooperation are central to modern practical software construction. While human aspects were recognized as important over 30 years ago, recent changes in the software domain have made cooperative and human aspects of software engineering even more significant. This special issue of IEEE Software presents a sample of current research in this field illustrating the wide variety of approaches, software domains and activities in which human and cooperative aspects are being investigated.     

Investigating a file transfer protocol using CSP and B

In this paper a file transmission protocol specification is developed using the combination of two formal methods: CSP and B. The aim is to demonstrate that it is possible to integrate two well established formal methods whilst maintaining their individual advantages. We discuss how to compositionally verify the specification and ensure that it preserves some abstract properties. We also discuss how the structure of the specification follows a particular style which may be generally applicable when modelling other protocols using this combination .     

Linear Neighborhood Propagation and Its Applications

In this paper, a novel graph-based transductive classification approach, called Linear Neighborhood Propagation, is proposed. The basic idea is to predict the label of a data point according to its neighbors in a linear way. This method can be cast into a second-order intrinsic Gaussian Markov random field framework. Its result corresponds to a solution to an approximate inhomogeneous biharmonic equation with Dirichlet boundary conditions. Different from existing approaches, our approach provides a novel graph structure construction method by introducing multiple-wise edges instead of pairwise edges, and presents an effective scheme to estimate the weights for such multiple-wise edges. To the best of our knowledge, these two contributions are novel for semi-supervised classification. The experimental results on image segmentation and transductive classification demonstrate the effectiveness and efficiency of the proposed approach.     

Effect of 'ropy' strains of Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus on rheology of stirred yogurt

The TA-TX2 Texture Analyser and the Brookfield RVT Viscometer have been used to investigate the contribution of ropiness to the texture of stirred yogurts made using ropy strains of bacteria. Back extrusion and texture profile analysis, not commonly used to quantify rheological properties of semi-solid foods, have been found useful in distinguishing the contribution of exopolysaccharides to different texture attributes (Toba et al ., 1990). Thus ropiness, a characteristic which is imparted to the product as a result of fermentation with particular polysaccharide-producing strains, contributes to 'adhesiveness', while 'firmness' and 'elasticity' are likely to be influenced more by the protein matrix of the yogurt than by secretion of the polysaccharide by the ropy strains. Effects on viscosity and ability to recover viscosity after disruption were apparent, although the contribution of ropiness was not always positive. Ropy strains increased viscosity of stirred yogurts when compared to yogurt made with non-ropy cultures. But, whilst a ropy Lactobacillus delbrueckii ssp. bulgaricus (Lb r⁺) combined with a non-ropy Streptococcus thermophilus (St r⁻) produced a viscous product which recovered its viscosity well, a yogurt made by combining both ropy strains did not recover its viscosity as well as yogurt made by combining two non-ropy cultures and lost its structure more rapidly during the destructive testing. These results show therefore that inclusion of a ropy strain will not always lead to improved texture attributes, that while ropy strains may increase viscosity they may not influence 'firmness' and lend support to the view that this latter attribute is more influenced by protein–protein interactions.     

The prevention of depressive symptoms in rural school children: A randomized controlled trial.

A controlled trial was conducted to evaluate a prevention program aimed at reducing depressive and anxious symptoms in rural school children. Seventh-grade children with elevated depression were selected. Nine primary schools (n=90) were randomly assigned to receive the program, and 9 control schools (n=99) received their usual health education classes. Children completed questionnaires on depression, anxiety, explanatory style, and social skills. Parents completed the Child Behavior Checklist (T. M. Achenbach, 1991). No intervention effects were found for depression. Intervention group children reported less anxiety than the control group after the program and at 6-month follow-up and more optimistic explanations at postintervention. Intervention group parents reported fewer child internalizing and externalizing symptoms at postintervention only. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Racism: Calling a Spade a Spade.

Research has documented the deleterious effects of racism on the mental health of people of color. However, the practice of psychotherapy sorely underutilizes these important findings, thereby providing less-than-optimum care. Through the presentation of research and personal stories, the author discusses the necessity of naming racism and of identifying its effects. Guidelines are suggested for transforming difficult racial dialogues into healing experiences for clients, and the necessity of taking stands against racism inside and outside of the therapy office is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Models of motivation in software engineering

Motivation in software engineering is recognized as a key success factor for software projects, but although there are many papers written about motivation in software engineering, the field lacks a comprehensive overview of the area. In particular, several models of motivation have been proposed, but they either rely heavily on one particular model (the job characteristics model), or are quite disparate and difficult to combine. Using the results from our previous systematic literature review (SLR), we constructed a new model of motivation in software engineering. We then compared this new model with existing models and refined it based on this comparison. This paper summarises the SLR results, presents the important existing models found in the literature and explains the development of our new model of motivation in software engineering.     

Recent progress of (Ba,Sr)TiO<Subscript>3</Subscript> thin films for tunable microwave devices

The (Ba_1−xSr_x)TiO₃ (BST) ferroelectric thin films exhibit outstanding dielectric properties, even at high frequencies (>1 GHz), and large, electric-field dielectric tunability. This feature makes them suitable for developing a new class of tunable microwave devices. The dielectric properties and dielectric tuning property of BST thin films are closely related to the film compositions, substrate types, and post-deposition process. The successful implementation of BST films as high-frequency dielectrics in electrically tunable microwave devices requires a detailed understanding of both their processing and material properties. This paper will review the recent progress of BST thin films as active dielectrics for tunable microwave devices. The technical aspects of BST thin films, such as processing methods, post-annealing process, film compositions, film stress, oxygen defects, and interfacial structures between film and substrate, are briefly reviewed and discussed with specific samples from the recent literature. The major issues requiring additional investigations to improve the dielectric properties of BST thin films for tunable microwave applications are also discussed.     

Flaw-Tolerance and Crack-Resistance Properties of Alumina-Aluminum Titanate Composites with Tailored Microstructures

The microstructures of alumina-aluminum titanate (A-AT) composites have been tailored with the intent of altering their crack-resistance ( R - or T -curve) behavior and resulting flaw tolerance. Specifically, two microstructural parameters which influence grain-localized crack bridging, viz., (i) internal residual stresses and (ii) microstructural coarseness, have been investigated. Particulate aluminum titanate was added to alumina to induce intense internal residual stresses from extreme thermal expansion mismatch. It was found that A-AT composites with uniformly distributed 20–30 vol% aluminum titanate ("duplex") showed significantly improved flaw tolerance over single-phase alumina. Coarsening of the duplex microstructure via grain growth scaling was relatively ineffective in improving the flaw tolerance further. Onset of spontaneous microcracking precluded further exploitation of this scaling approach. Therefore, an alternative approach to coarsening was developed, in which a uniform distribution of large alumina grains was incorporated within a fine-grain A-AT matrix ("duplex-bimodal"), via a powder processing route. The duplex-bimodal composites yielded excellent flaw tolerance with steady-state toughness of ∼8 MPa˙m^1/2. A qualitative model for microstructure development in these duplex-bimodal composites is presented.