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Main Concepts (main + concept)
Selected AbstractsTRIBLER: a social-based peer-to-peer systemCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 2 2008J. A. Pouwelse Abstract Most current peer-to-peer (P2P) file-sharing systems treat their users as anonymous, unrelated entities, and completely disregard any social relationships between them. However, social phenomena such as friendship and the existence of communities of users with similar tastes or interests may well be exploited in such systems in order to increase their usability and performance. In this paper we present a novel social-based P2P file-sharing paradigm that exploits social phenomena by maintaining social networks and using these in content discovery, content recommendation, and downloading. Based on this paradigm's main concepts such as taste buddies and friends, we have designed and implemented the TRIBLER P2P file-sharing system as a set of extensions to BitTorrent. We present and discuss the design of TRIBLER, and we show evidence that TRIBLER enables fast content discovery and recommendation at a low additional overhead, and a significant improvement in download performance. Copyright © 2007 John Wiley & Sons, Ltd. [source] Resilience thinking: Interview with Brian WalkerECOLOGICAL MANAGEMENT & RESTORATION, Issue 2 2007Tein McDonald Summary This interview with Brian Walker, chair of the research-based Resilience Alliance, outlines the main concepts and propositions behind ,resilience thinking' and touches on the importance of this paradigm for individuals and organizations involved in managing complex social-ecological systems. It refers to the origins, work and publications of the Resilience Alliance, listing and elaborating the key case studies used to illustrate the Alliance's main proposition that complex social-ecological systems do not behave in a predictable linear fashion. Rather, research indicates it is normal for complex systems to go through cycles of increasing and decreasing resilience and to have potential to shift, (in a self-organising way) to potentially undesirable states or entirely new systems if certain component variables are severely impacted by management. Such shifts can be novel and ,surprising', and are often not beneficial or desirable for societies. This is particularly the case where small-scale solutions push the problem upwards in a system, causing loss of resilience at a global scale. Predicting thresholds is therefore important to managers and is a key research focus for members of the Resilience Alliance who are currently building an accessible database to support decision-making in global natural resource management. [source] Simplified estimation of seismically induced settlementsINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 8 2003E. Vincens Abstract This paper proposes a predictive expression of settlements for a dry sand deposit overlying a bedrock and subjected to a seismic motion. The proposed formula combines geometrical and mechanical properties of the soil profile with classical characteristics of the input motion. One of the main concepts developed herein consists in regarding the input motion and the dynamical response as samples of random processes; another key concept consists in the common densification curve from Sawicki. The model introduces a parameter k identified by means of an extensive set of accelerograms. The main advantage of the proposed method consists in allowing fast comparisons of earthquake induced settlements for different soil and motion characteristics and therefore quantifying the damage power of a time-history input motion. Copyright © 2003 John Wiley & Sons, Ltd. [source] A review of reliable numerical models for three-dimensional linear parabolic problemsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 1 2007I. Faragó Abstract The preservation of characteristic qualitative properties of different phenomena is a more and more important requirement in the construction of reliable numerical models. For phenomena that can be mathematically described by linear partial differential equations of parabolic type (such as the heat conduction, the diffusion, the pricing of options, etc.), the most important qualitative properties are: the maximum,minimum principle, the non-negativity preservation and the maximum norm contractivity. In this paper, we analyse the discrete analogues of the above properties for finite difference and finite element models, and we give a systematic overview of conditions that guarantee the required properties a priori. We have chosen the heat conduction process to illustrate the main concepts, but engineers and scientists involved in scientific computing can easily reformulate the results for other problems too. Copyright © 2006 John Wiley & Sons, Ltd. [source] Enriching spaces in practice-based education to support collaboration while mobile: the case of teacher educationJOURNAL OF COMPUTER ASSISTED LEARNING, Issue 4 2007E.M. Morken Abstract Practice-based education is gaining a growing popularity in fields as diverse as, for example, software engineering, pedagogy and medical studies. In practice-based education learning takes place across different learning arenas and requires cooperation among all the actors involved in the learning process. However, mobility of students across these arenas impact deeply on cooperation patterns, and therefore on the learning process. In this paper we investigate the usage of shared display systems to promote cooperation among students in practice-based education. Our focus is on teacher education and the paper is based on our experiences with the teacher education programme at our university. Based on our observations of students out in practice, we discuss the importance of common spaces and the role of bulletin boards of different types. We then define high-level requirements for a shared display system to support practice-based education and we illustrate the main concepts with a demonstrator. Strengths and weaknesses of our approach are pointed out through an evaluation of the demonstrator. [source] Movement-to-music computer technology: a developmental play experience for children with severe physical disabilitiesOCCUPATIONAL THERAPY INTERNATIONAL, Issue 2 2007Cynthia Tam Abstract Children with severe physical disabilities often lack the physical skills to explore their environment independently, and to play with toys or musical instruments. The movement-to-music (MTM) system is an affordable computer system that allows children with limited movements to play and create music. The present study explored parents' experiences of using the MTM system with their children. A qualitative methodology employing in-depth interview techniques was used with six mothers and their children. The themes extracted from the data were organized under two main concepts of the International Classification of Functioning, Disability, and Health (ICF) (WHO, 2001) framework. The results showed that the MTM expanded horizons for the child along the ICF health dimensions and the MTM had a positive impact on ICF environmental determinants of health. The small sample size should be noted as a limitation of this study. Further research should be carried out with a larger sample of children with restricted mobility to obtain a better understanding of the impact of MTM technology on children's psychosocial development. Copyright © 2007 John Wiley & Sons, Ltd. [source] Is ,Normal Grief' a Mental Disorder?THE PHILOSOPHICAL QUARTERLY, Issue 200 2000Stephen Wilkinson I argue that grief (including ,normal grief') is a mental disorder. I discuss the main concepts involved briefly, and state the prima facie case in favour of the view that grief is a disorder. I consider objections that grief is not a disorder because (a) it is a normal response; (b) it is more healthy than failing to grieve; (c) it involves cognitive good; (d) it is a rational response; (e) it ought not to be medicalized or treated; (f ) it has a ,distinct sustaining cause'. Each objection is flawed, and I conclude that there is a strong case for regarding even ,normal' grief as a disorder. Alternatively, the arguments in this paper may be taken as attacking ,orthodoxrsquo; definitions of mental health (e.g., in DSM 4th edn) by providing an extended discussion of one particular counter-example. [source] Clinical reasoning in neurology: Use of the repertory grid technique to investigate the reasoning of an experienced occupational therapistAUSTRALIAN OCCUPATIONAL THERAPY JOURNAL, Issue 4 2009Kathy Kuipers Background/aim:,The aim of this paper is to describe the use of a structured interview methodology, the repertory grid technique, for investigating the clinical reasoning of an experienced occupational therapist in the domain of upper limb hypertonia as a result of brain injury. Method:,Repertory grid interviews were completed before and after exposure to a protocol designed to guide clinical reasoning and decision-making in relation to upper limb neurological rehabilitation. Data were subjected to both qualitative and quantitative analyses. Results:,Qualitative analysis focussed on clinical reasoning content. Common themes across the pre- and post-exposure interviews were the use of theoretical frameworks and practice models, the significance of clinical expertise, and discrimination of ,broad' and ,specific' aspects, as well as differentiation between ,therapist and client-related' aspects of the clinical situation. Quantitative analysis indicated that for both pre- and post-exposure repertory grids, clinical reasoning was structured in terms of two main concepts. In the pre-exposure grid, these were related to the therapist's role, and to the ,scope' of practice tasks (either broad or specific). In the post-exposure grid the two main concepts were upper limb performance, and client-centred aspects of the therapy process. Conclusions:,The repertory grid technique is proposed as an effective tool for exploring occupational therapy clinical reasoning, based on its capacity for accessing personal frames of reference, and elucidating both the meaning and the structure supporting clinical reasoning. [source] Prodrug Strategies in Anticancer ChemotherapyCHEMMEDCHEM, Issue 1 2008Felix Kratz Dr. Abstract The majority of clinically approved anticancer drugs are characterized by a narrow therapeutic window that results mainly from a high systemic toxicity of the drugs in combination with an evident lack of tumor selectivity. Besides the development of suitable galenic formulations such as liposomes or micelles, several promising prodrug approaches have been followed in the last decades with the aim of improving chemotherapy. In this review we elucidate the two main concepts that underlie the design of most anticancer prodrugs: drug targeting and controlled release of the drug at the tumor site. Consequently, active and passive targeting using tumor-specific ligands or macromolecular carriers are discussed as well as release strategies that are based on tumor-specific characteristics such as low pH or the expression of tumor-associated enzymes. Furthermore, other strategies such as ADEPT (antibody-directed enzyme prodrug therapy) and the design of self-eliminating structures are introduced. Chemical realization of prodrug approaches is illustrated by drug candidates that have or may have clinical importance. [source] | |||||||||||||