New lower bounds for the independence number of sparse graphs and hypergraphs

We obtain new lower bounds for the independence number of $K_r$-free graphs and linear $k$-uniform hypergraphs in terms of the degree sequence. This answers some old questions raised by Caro and Tuza \cite{CT91}. Our proof technique is an extension of a method of Caro and Wei \cite{CA79, WE79}, and we also give a new short proof of the main result of \cite{CT91} using this approach. As byproducts, we also obtain some non-trivial identities involving binomial coefficients

Realizing live sequence charts in SystemVerilog.

The design of an embedded control system starts with an investigation of properties and behaviors of the process evolving within its environment, and an analysis of the requirement for its safety performance. In early stages, system requirements are often specified as scenarios of behavior using sequence charts for different use cases. This specification must be precise, intuitive and expressive enough to capture different aspects of embedded control systems. As a rather rich and useful extension to the classical message sequence charts, live sequence charts (LSC), which provide a rich collection of constructs for specifying both possible and mandatory behaviors, are very suitable for designing an embedded control system. However, it is not a trivial task to realize a high-level design model in executable program codes effectively and correctly. This paper tackles the challenging task by providing a mapping algorithm to automatically synthesize SystemVerilog programs from given LSC specifications

Young\u27s modulus of [111] germanium nanowires

This paper reports a diameter-independent Young’s modulus of 91.9 ± 8.2 GPa for [111] Germaniumnanowires (Ge NWs). When the surface oxide layer is accounted for using a core-shell NW approximation, the YM of the Ge core approaches a near theoretical value of 147.6 ± 23.4 GPa. The ultimate strength of a NW device was measured at 10.9 GPa, which represents a very high experimental-to-theoretical strength ratio of ∼75%. With increasing interest in this material system as a high-capacity lithium-ion battery anode, the presented data provide inputs that are essential in predicting its lithiation-induced stress fields and fracture behavior

A Typology of Interorganizational Relationships: Implications for IS Design

We are currently witnessing an explosion in the number and variety of interorganizational relationships reported in the business press that are often described using buzzwords such as \u27partnership\u27 and strategic alliance\u27. Unfortunately, theory lags practice in the examination of this phenomenon that is increasingly becoming the model for success in many industries. From the perspective of Transaction Cost Economics, a dominant theoretical anchor, these interorganizational relationships are considered to fall between the well described extremes of market exchange and hierarchically controlled exchanges and belong to a less understood type termed the \u27hybrid\u27 (Clemons, Reddi, Row 1993, Hennart 1994). Information Technology (IT) is often the fundamental enabler of these non traditional forms of organizing (Quinn 1992) and a theoretical understanding of the phenomenon is indispensable to enable the effective exploitation of IT capabilities in such relationships. In an exploratory study to derive a process based understanding of interorganizational relationships in the distribution channel, we find evidence that interorganizational relationships can be classified into four distinct types. The four types differ significantly in the processes of operational control and boundary management as well as in the nature of information exchange and the role of information technologies. The results provide a greater understanding of action in interorganizational relationships and have implications for the design of interorganizational information systems (IOS)

Gaps That Matter: The Influence of Perspectives on IS Service Quality

It is now well established that firms need to make significant changes to organizational processes to derive advantages from the deployment of Information Technologies (IT). The strength of the interface between Information Systems providers (the IS group) and their users in organizations is a critical determinant of the firm\u27s ability to visualize, design and deploy appropriate IT solutions and make the necessary organizational design changes to utilize the investments in IT (Davenport 1992). While the creation of partnerships between IS groups and their users has often been highlighted as important to ensure effective IT implementation (Lasher, Ives, Jarvenpaa 1991), the critical dimensions along which the two groups need to be convergent and the impact of convergence on outcomes for users has received little attention. Using the theoretical lens of role theory, we examine the impact of convergence in perspectives on six key issues between IS groups and the users that they serve in three large organizations. Our results provide empirical support for the view that convergence in the perspectives of IS and user groups is associated with increased levels of Service Quality. One contribution of this study is the explication of key issues on which convergence of perspectives between IS and User groups is central to the improvement of the quality of services provided by the IS group

Gravitational Lensing Characteristics of the Transparent Sun

The transparent Sun is modeled as a spherically symmetric and centrally condensed gravitational lens using recent Standard Solar Model (SSM) data. The Sun's minimum focal length is computed to a refined accuracy of 23.5 +/- 0.1 AU, just beyond the orbit of Uranus. The Sun creates a single image of a distant point source visible to observers inside this minimum focal length and to observers sufficiently removed from the line connecting the source through the Sun's center. Regions of space are mapped where three images of a distant point source are created, along with their associated magnifications. Solar caustics, critical curves, and Einstein rings are computed and discussed. Extremely high gravitational lens magnifications exist for observers situated so that an angularly small, unlensed source appears near a three-image caustic. Types of radiations that might undergo significant solar lens magnifications as they can traverse the core of the Sun, including neutrinos and gravitational radiation, are discussed

Evaluating the Effectiveness of an Established Community-Based Eccentric Viewing Rehabilitation Training Model—the EValuation Study

Purpose: This study evaluated the community-based eccentric viewing (EV) training offered across the United Kingdom by the Macular Society. Volunteer trainers deliver free one-to-one training, usually in learners' homes. They also share information about lighting, magnification, social support, and low-vision technology. Methods: The audio-recorded reading performance of learners was compared before and after training. Telephone questionnaires were used to assess life satisfaction, amount of reading performed, and health- and vision-related quality of life. Learners were also interviewed to obtain their subjective opinions. Results: A total of 121 learners completed all stages of the study. There was no significant change in maximum reading speed. A statistically significant (P < 0.001) but small improvement in both critical print size and threshold print size was found, but frequency and duration of reading did not increase. There was a borderline significant (P = 0.022) increase in “life satisfaction” for the learners, but a highly significant (P < 0.001) decrease in their “positive affect.” There was no change in health- or vision-related quality of life, or in the difficulty experienced in performing everyday tasks. However, according to learner interviews, 72% felt they had achieved a positive outcome from the training, and 75% felt they had received helpful advice in addition to the EV training. Conclusions: The lack of improvement of reading speed and modest improvement in threshold print size should be interpreted in the context of the unique features of this EV program, since many learners who would seem to have limited scope for improvement still undertake the training

Evaluating the effectiveness of the Macular Society Eccentric Viewing Rehabilitation Training - the evaluation study

Background: The Macular Society have provided Eccentric Viewing (EV) training across the UK since 2006, by training volunteers to deliver a community based model. Trainers deliver free one-to-one training during 1-3, 1 hour over a 2–3 month period, usually in learners’ homes. During sessions, trainers also share handy hints and tips about (e.g.) lighting, magnification, social support and technology. Methods: An independent research team evaluated the effectiveness of the programme using a wide range of outcome measures, including reading ability; well-being; and health- and vision-related quality of life. Learners were also interviewed for their opinions. Results: 121 learners completed all stages of the study. They perceived the trainers to be knowledgeable, well- trained and friendly. 75% of learners felt they had received helpful advice in addition to EV training; and 65% of learners felt they had achieved a positive outcome. Objective results were less encouraging. There was a borderline significant increase in “life satisfaction” for the learners, but a highly significant decrease in their “positive affect” (PANAS). There was no significant change in measured reading speed or acuity (MNRead-style test); or in health- or vision-related quality of life (EQ-5D-5L; VisQoL; NEI-VFQ-7). There was, however, an increase in the proportion of learners reporting that they could read a newspaper with “little or no difficulty” (from 13% to 23%); and a significant decrease in the number reporting “extreme difficulty” whilst watching television (from 27% to 15%). Conclusion: The findings may be explained by some of the unique features of this programme: many learners who would seem to have limited scope for improvement still wish to undertake the training; the interval between training sessions is lengthy; and there is no link to a low vision assessment. Acknowledgements: Commissioned and funded by the Macular Society