UML的前途

UML（统一建模语言）成为标准已经超过12年了。在这些年里，人们对UML的看法各不相同，有喜爱的，也有讨厌的。在这篇文章中，我们将讨论当前UML规范的不足之处．并建议如何让它敏捷、更精益、更智慧、更有弹性——简而言之，     

A Converging Wall-Jet Instrument for Ion Selective Electrode Dynamic Response Studies

Abstract

Ion selective electrodes are used to conduct real-time measurements of gaseous thermal degradation products from halon replacement experiments. Response characteristics of these ion selective electrodes are needed to address potential interferences and surface poisoning experienced under field conditions. The design and the fabrication of an in situ, converging wall-jet instrument for the measurement of the dynamic responses of ion selective electrodes are described. Various time delays associated with the generation and detection of ion activity steps have been quantitatively determined.

Dynamic response measurements for iodide steps on a Corning iodide/cyanide ion selective electrode are comparable to those obtained on the best of the earlier instrument designs, the in situ, switched wall-jet instrument. The advantages of the converging wall-jet instrument over the switched wall-jet instrument are identified.     

Suitability of European climate for the Asian tiger mosquito Aedes albopictus: recent trends and future scenarios

The Asian tiger mosquito (Aedes albopictus) is an invasive species that has the potential to transmit infectious diseases such as dengue and chikungunya fever. Using high-resolution observations and regional climate model scenarios for the future, we investigated the suitability of Europe for A. albopictus using both recent climate and future climate conditions. The results show that southern France, northern Italy, the northern coast of Spain, the eastern coast of the Adriatic Sea and western Turkey were climatically suitable areas for the establishment of the mosquito during the 1960–1980s. Over the last two decades, climate conditions have become more suitable for the mosquito over central northwestern Europe (Benelux, western Germany) and the Balkans, while they have become less suitable over southern Spain. Similar trends are likely in the future, with an increased risk simulated over northern Europe and slightly decreased risk over southern Europe. These distribution shifts are related to wetter and warmer conditions favouring the overwintering of A. albopictus in the north, and drier and warmer summers that might limit its southward expansion.     

A Survey of Symbolic Methods in Computational Analysis of Cryptographic Systems

Since the 1980s, two approaches have been developed for analyzing security protocols. One of the approaches relies on a computational model that considers issues of complexity and probability. This approach captures a strong notion of security, guaranteed against all probabilistic polynomial-time attacks. The other approach relies on a symbolic model of protocol executions in which cryptographic primitives are treated as black boxes. Since the seminal work of Dolev and Yao, it has been realized that this latter approach enables significantly simpler and often automated proofs. However, the guarantees that it offers with respect to the more detailed computational models have been quite unclear. For more than 20 years the two approaches have coexisted but evolved mostly independently. Recently, significant research efforts attempt to develop paradigms for cryptographic systems analysis that combines the best of both worlds. There are two broad directions that have been followed. Computational soundness aims to establish sufficient conditions under which results obtained using symbolic models imply security under computational models. The direct approach aims to apply the principles and the techniques developed in the context of symbolic models directly to computational ones. In this paper we survey existing results along both of these directions. Our goal is to provide a rather complete summary that could act as a quick reference for researchers who want to contribute to the field, want to make use of existing results, or just want to get a better picture of what results already exist.     

Flexural behaviour and strength of cold-formed steel L-headers

Cold-formed steel headers are structural components used over wall openings in cold-formed steel residential and light commercial construction. Recently, there has been an increased interest in cold-formed L-headers among homebuilders primarily due to their ease of installation and low material cost. The findings from an extensive laboratory testing program, of full-scale single and double cold-formed steel L-headers are presented in this paper. The objective of the research was to investigate the flexural behaviour and strength of L-headers under both gravity and uplift loads. Based on the results improved ultimate strength design expressions and new deflection expressions for a wide range of L-header assemblies have been proposed.     

Development of a cost effective probe for the long term monitoring of straw bale buildings

This paper reviews current methodologies for measuring the moisture content of straw bale walls in buildings. It discusses the development of an affordable and accurate moisture probe that has been designed to be easily assembled by the builder or owner of a straw bale building from items readily available in the United Kingdom (UK). The probe uses a timber block inserted into the wall, relying upon the measurable moisture variances of the timber and relating this to the surrounding straw. The probes are designed to be used in pairs of varying length, taking measurements at different depths to give an estimate of the moisture gradient through the wall. In order to properly calibrate this device, a full set of sorption and desorption isotherms were established for both Oat and Wheat straw and three different timber species. The results from an environmental chamber have been compared to readings from specimens of the new probe installed in a straw bale house in the south west of the UK. The results were found to be consistent, to within 2%, with the laboratory findings.     

Interactions between early parenting and a polymorphism of the child's dopamine transporter gene in predicting future child conduct disorder symptoms.

Mounting evidence suggests that genetic risks for mental disorders often interact with the social environment, but most studies still ignore environmental moderation of genetic influences. The authors tested interactions between maternal parenting and the variable number tandem repeat (VNTR) polymorphism in the 3′ untranslated region of the dopamine transporter gene in the child to increase understanding of gene–environment interactions involving early parenting. Participants were part of a 9-year longitudinal study of 4- to 6-year-old children who met criteria for attention-deficit/hyperactivity disorder (ADHD) and demographically matched controls. Maternal parenting was observed during standard mother–child interactions in Wave 1. The child's conduct disorder (CD) symptoms 5–8 years later were measured using separate structured diagnostic interviews of the mother and youth. Controlling for ADHD symptoms and child disruptive behavior during the mother–child interaction, there was a significant inverse relation between levels of both positive and negative parenting at 4–6 years and the number of later CD symptoms, but primarily among children with 2 copies of the 9-repeat allele of the VNTR. The significant interaction with negative parenting was replicated in parent and youth reports of CD symptoms separately. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

英国公司QuantaSol打破太阳能电池记录

帝国理工学院(Imperial Collage)剥离出来的QuantaSol声称,他们已经打破了单结太阳能电池的世界记录。当曝露在500倍聚光的条件下,应力平衡的量子阱太阳能电池的转换效率记录为28.3%。     

Project governance: case studies on financial incentives

Appropriate financial incentives within construction project coalitions can contribute to effective project governance. However, the dearth of primary research material is partly attributed to the lack of a suitable methodology with which to study projects. Social network analysis (SNA) is proposed as an analytical tool to explore coalition governance. Primary data are presented for three European case studies employing quite different approaches to the use of financial incentives in project governance. The case studies investigate pain share/gain share arrangements implemented under a prime contracting procurement approach; an unusual use of activity-related penalties in the French system of procurement; and the use of guaranteed maximum price supplements within a UK standard form of (without contractor's design) building contract. The use of SNA enables the observation of a number of transaction sets and the formulation of a framework for the quantification of construction project governance. The first case study demonstrates the decentralization of client-orientated financial management, from consultant quantity surveyor to a number of multidisciplinary cluster leaders. The second case study illustrates the importance of incentive contiguity in effective project governance. The third case study uses SNA to demonstrate the way in which financial governance could be transformed through the transference of client-orientated financial management from the client and their professional adviser to the main contractor.

Les incitations financières appropriées, dans le cadre d'un fonds commun relatif à un projet de construction, peuvent contribuer à une gestion efficace du projet. Or, la pénurie de matériel de recherche primaire est attribuée, en partie, à l'absence d'une méthodologie appropriée permettant d'étudier de tels projets. Dans cet article, l'auteur propose l'analyse du réseau social (SNA) comme outil analytique permettant d'explorer la gouvernance collective. L'article présente des données primaires concernant trois études de cas européennes employant des méthodologies tout à fait différentes d'utilisation des incitations financières dans la gouvernance du projet. Ces études de cas portent sur les mécanismes de partage des difficultés/partage des gains mis en ?uvre au titre des approvisionnements par un maître d'?uvre, sur l'usage inhabituel de pénalités liées à l'activité dans le système français des approvisionnements et sur l'usage de suppléments de prix garantis et maximaux dans une forme standard du SNA, au Royaume-Uni, permettant l'observation d'un certain nombre d'ensembles de transactions et la formulation d'un cadre pour la quantification de la gouvernance du projet de construction. La première étude de cas démontre la décentralisation de la gestion financière orientée ‘client’, du consultant métreur-vérificateur vers un certain nombre de responsables de groupes pluridisciplinaires. La deuxième étude de cas illustre l'importance de la contiguïté incitative dans une gouvernance de projet efficace. La troisième étude de cas utilise la SNA pour démontrer comment pourrait être transformée la gouvernance financière en passant d'une gestion financière orientée ‘client’, du client et de son conseiller professionnel, vers le maître d'?uvre.

Mots-clés: modèles de développement, collaboration, gouvernance, incitations, contrats de maître d'oeuvre, approvisionnement, dynamique du projet, organisation du projet, analyse du réseau social, intégration des équipes.