Practical Object-Oriented Back-in-Time Debugging

Back-in-time debuggers are extremely useful tools for identifying the causes of bugs, as they allow us to inspect the past states of objects no longer present in the current execution stack. Unfortunately the "omniscient" approaches that try to remember all previous states are impractical because they either consume too much space or they are far too slow. Several approaches rely on heuristics to limit these penalties, but they ultimately end up throwing out too much relevant information. In this paper we propose a practical approach to back-in-time debugging that attempts to keep track of only the relevant past data. In contrast to other approaches, we keep object history information together with the regular objects in the application memory. Although seemingly counter-intuitive, this approach has the effect that past data that is not reachable from current application objects (and hence, no longer relevant) is automatically garbage collected. In this paper we describe the technical details of our approach, and we present benchmarks that demonstrate that memory consumption stays within practical bounds. Furthermore since our approach works at the virtual machine level, the performance penalty is significantly better than with other approaches.

Context-Oriented Programming

Context-dependent behavior is becoming increasingly important for a wide range of application domains, from pervasive computing to common business applications. Unfortunately, mainstream programming languages do not provide mechanisms that enable software entities to adapt their behavior dynamically to the current execution context. This leads developers to adopt convoluted designs to achieve the necessary runtime flexibility. We propose a new programming technique called Context-oriented Programming (COP) which addresses this problem. COP treats context explicitly, and provides mechanisms to dynamically adapt behavior in reaction to changes in context, even after system deployment at runtime. In this paper we lay the foundations of COP, show how dynamic layer activation enables multi-dimensional dispatch, illustrate the application of COP by examples in several language extensions, and demonstrate that COP is largely independent of other commitments to programming style.

Supporting Task-oriented Navigation in IDEs with Configurable HeatMaps

Mainstream IDEs generally rely on the static structure of a software project to support browsing and navigation. We propose HeatMaps, a simple but highly configurable technique to enrich the way an IDE displays the static structure of a software system with additional kinds of information. A heatmap highlights software artifacts according to various metric values, such as bright red or pale blue, to indicate their potential degree of interest. We present a prototype system that implements heatmaps, and we describe an initial study that assesses the degree to which different heatmaps effectively guide developers in navigating software.

Object-Oriented Reengineering Patterns

The rapid growth of object-oriented development over the past twenty years has given rise to many object-oriented systems that are large, complex and hard to maintain. Object-Oriented Reengineering Patterns addresses the problem of understanding and reengineering such object-oriented legacy systems. This book collects and distills successful techniques in planning a reengineering project, reverse-engineering, problem detection, migration strategies and software redesign. The material in this book is presented as a set of "reengineering patterns" --- recurring solutions that experts apply while reengineering and maintaining object-oriented systems. The principles and techniques described in this book have been observed and validated in a number of industrial projects, and reflect best practice in object-oriented reengineering.

MHP Oriented Interactive Augmented Reality System for Sports Broadcasting Environments

Television and movie images have been altered ever since it was technically possible. Nowadays embedding advertisements, or incorporating text and graphics in TV scenes, are common practice, but they can not be considered as integrated part of the scene. The introduction of new services for interactive augmented television is discussed in this paper. We analyse the main aspects related with the whole chain of augmented reality production. Interactivity is one of the most important added values of the digital television: This paper aims to break the model where all TV viewers receive the same final image. Thus, we introduce and discuss the new concept of interactive augmented television, i. e. real time composition of video and computer graphics - e.g. a real scene and freely selectable images or spatial rendered objects - edited and customized by the end user within the context of the user's set top box and TV receiver.

The role of specialisation in the promotion of young football talents: A person-oriented study

This paper investigates the controversial question whether it is more effective to promote specialisation in a specific sport at the beginning of a career or whether to encourage a broad range of sports when promoting competitive sports talents in order for them to achieve a high level of performance in adulthood. The issue of promoting talents depends on human developmental processes and therefore raises developmental scientific questions. Based on recent, dynamic-interactionist concepts of development, we assume a person-oriented approach focussing on the person as a whole rather than individual features. Theoretical considerations lead to four interacting factors being summarised to form a subsystem: childhood training. The relative weights of these factors lead to patterns. By relating these to a performance criterion at the age of peak performance, particularly promising developmental patterns may be identified. One hundred fifty-nine former Swiss football talents were retrospectively interviewed about their career and the data analysed using the LICUR method. Two early career patterns were identified as having a favourable influence on adult performance. Both are characterised by an above-average amount of in-club training. One pattern also exhibits an above-average amount of informal football played outside the club, the other above-average scores for activity in other sports. Hence, comprehensive training and practice inside and outside the club form the basis for subsequent football expertise.

Structural rearrangements of the central region of the morbillivirus attachment protein stalk domain trigger F protein refolding for membrane fusion

It is unknown how receptor binding by the paramyxovirus attachment proteins (HN, H, or G) triggers the fusion (F) protein to fuse with the plasma membrane for cell entry. H-proteins of the morbillivirus genus consist of a stalk ectodomain supporting a cuboidal head; physiological oligomers consist of non-covalent dimer-of-dimers. We report here the successful engineering of intermolecular disulfide bonds within the central region (residues 91-115) of the morbillivirus H-stalk; a sub-domain that also encompasses the putative F-contacting section (residues 111-118). Remarkably, several intersubunit crosslinks abrogated membrane fusion, but bioactivity was restored under reducing conditions. This phenotype extended equally to H proteins derived from virulent and attenuated morbillivirus strains and was independent of the nature of the contacted receptor. Our data reveal that the morbillivirus H-stalk domain is composed of four tightly-packed subunits. Upon receptor binding, these subunits structurally rearrange, possibly inducing conformational changes within the central region of the stalk, which, in turn, promote fusion. Given that the fundamental architecture appears conserved among paramyxovirus attachment protein stalk domains, we predict that these motions may act as a universal paramyxovirus F-triggering mechanism.

Successful Careers in Football – Findings of a Person-Oriented Study

A successful career in football is the result of the appropriate interaction between different aspects of an individual’s life, since the various areas and phases of one’s life depend on each other. An endogenous causal relationship exists throughout a person’s entire history (Mayer, 1990). In particular, their family, work and sports career must be tuned to each other. The transition from the initial stages of education (compulsory schooling) to vocational training, which coincides with the beginning of the selection for the national youth teams, is a particularly critical phase (Wylleman, Theeboom, & Lavallee, 2004). In order to do justice to the overall life situation of a young sports talent during this transition phase, we have adopted a holistic perspective and follow Bergman, Magnusson and El-Khouri (2003) in using a person-oriented and systemic approach. In doing so, our main focus lies on the person-environment system. This overall system is made up of various subsystems, consisting of several operating factors which interact with one another. The different levels to which these operating factors are expressed lead to observable patterns, which can be summarised in the form of types. Particularly promising types can therefore be identified and the developmental process can be described. Former players on the Swiss U16 to U21 national football teams, born between 1981 and 1987 (n=159), were interviewed concerning their careers, and the operating factors school/vocational training, family support and sports environment were examined. With the help of the LICUR method (Linking of Clusters after removal of Residue) (Bergman et al., 2003), developmental types were identified which were promising in terms of achieving top performance in adulthood. A range of developmental types and anti-types emerge for the transition from the under-15 phase to the over-16 phase. One particularly promising type is observed in the over-16 phase, for which the operating factors education, family support and participation in national U16 to U18 teams have slightly above-average scores, with scores that are well above average in the sports environment.

A Team-Oriented Investigation of ERP Post-Implementation Integration Projects: How Cross-Functional Collaboration Influences ERP Benefits

The benefits companies achieve by implementing an ERP system vary considerably. Many companies need to adapt their ERP integration solution in the post-implementation stage. But after the completion of such a usually very complex integration project, benefits do not emerge by all means. A misfit between the organization and the IS, especially the aspect of cross-functional team collaboration, could explain these divergences. Using an initial theoretical framework, we conducted a single case study to explore the team-oriented perceptions in a post-implementation ERP integration project. To analyze the benefits and the influences in greater depth we disentangled the integration benefits into their particular parts (process, system and information quality). Our findings show that post-implementation ERP integration changes are not always perceived as beneficiary by the involved teams and that cross-functional collaboration has an important influence.