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排序方式: 共有289条查询结果,搜索用时 15 毫秒
281.
A Dynamic Travel Time Model for Spillback 总被引:1,自引:1,他引:0
In this paper we introduce travel time models that incorporate spillback and bottleneck phenomena. In particular, we study a model for determining the link travel times for drivers entering a link as well as drivers already in the link but whose travel times are affected by a significant change in traffic conditions (e.g. spillback or bottleneck phenomena). To achieve this goal, we extend the fluid dynamics travel time models proposed by Perakis (1997)and subsequently by Kachani (2002), and Kachani and Perakis (2001), to also incorporate such phenomena. These models utilize fluid dynamics laws for compressible flow to capture a variety of flow patterns such as the formation and dissipation of queues, drivers’ response to upstream congestion or decongestion and drivers’ reaction time. We propose variants of these models that explicitly account for spillback and bottleneck phenomena. Our investigation considers both separable and non-separable velocity functions. 相似文献
282.
Formal mentoring: Lessons learned from past practice. 总被引:1,自引:0,他引:1
Formal mentoring programs are often implemented to help early career professionals; however, research on these programs has found mixed support. The general literature on formal mentoring programs has shifted from early studies comparing informal and formal mentoring to studies of the program characteristics related to success. A pilot program for formal mentoring of early career psychologists is presented for case study. Although the program was small and matching mentors and mentees proved difficult, reactions from some participants indicated successful mentoring. Drawing on lessons learned from the program and the general literature on formal mentoring, the author focuses on the matching process, training and program resources, and program administration. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
283.
Context-aware service engineering: A survey 总被引:2,自引:0,他引:2
Georgia M. Kapitsaki Author Vitae George N. Prezerakos Author Vitae Nikolaos D. Tselikas Author Vitae 《Journal of Systems and Software》2009,82(8):1285-1297
Context constitutes an essential part of service behaviour, especially when interaction with end-users is involved. As observed from the literature, context handling in service engineering has been during recent years a field of intense research, which has produced several interesting approaches. In this paper, we present research efforts that attempt mainly to decouple context handling from the service logic. We enumerate all context management categories, but focus on the most appropriate for service engineering, namely source code level, model-driven and message interception, taking also into account the fact that these have not been dealt with in detail in other surveys. A representative example is used to illustrate more precisely how these approaches can be used. Finally, all three categories are compared based on a number of criteria. 相似文献
284.
Risk Governance of Emerging Technologies Demonstrated in Terms of its Applicability to Nanomaterials
Panagiotis Isigonis Antreas Afantitis Dalila Antunes Alena Bartonova Ali Beitollahi Nils Bohmer Evert Bouman Qasim Chaudhry Mihaela Roxana Cimpan Emil Cimpan Shareen Doak Damien Dupin Doreen Fedrigo Valrie Fessard Maciej Gromelski Arno C. Gutleb Sabina Halappanavar Peter Hoet Nina Jeliazkova Stphane Jomini Sabine Lindner Igor Linkov Eleonora Marta Longhin Iseult Lynch Ineke Malsch Antonio Marcomini Espen Mariussen Jesus M. de la Fuente Georgia Melagraki Finbarr Murphy Michael Neaves Rolf Packroff Stefan Pfuhler Tomasz Puzyn Qamar Rahman Elise Rundn Pran Elena Semenzin Tommaso Serchi Christoph Steinbach Benjamin Trump Ivana Vinkovi Vr
ek David Warheit Mark R. Wiesner Egon Willighagen Maria Dusinska 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(36)
Nanotechnologies have reached maturity and market penetration that require nano‐specific changes in legislation and harmonization among legislation domains, such as the amendments to REACH for nanomaterials (NMs) which came into force in 2020. Thus, an assessment of the components and regulatory boundaries of NMs risk governance is timely, alongside related methods and tools, as part of the global efforts to optimise nanosafety and integrate it into product design processes, via Safe(r)‐by‐Design (SbD) concepts. This paper provides an overview of the state‐of‐the‐art regarding risk governance of NMs and lays out the theoretical basis for the development and implementation of an effective, trustworthy and transparent risk governance framework for NMs. The proposed framework enables continuous integration of the evolving state of the science, leverages best practice from contiguous disciplines and facilitates responsive re‐thinking of nanosafety governance to meet future needs. To achieve and operationalise such framework, a science‐based Risk Governance Council (RGC) for NMs is being developed. The framework will provide a toolkit for independent NMs' risk governance and integrates needs and views of stakeholders. An extension of this framework to relevant advanced materials and emerging technologies is also envisaged, in view of future foundations of risk research in Europe and globally. 相似文献
285.
Size-dependent magnetic properties of single-crystalline multiferroic BiFeO3 nanoparticles 总被引:1,自引:0,他引:1
As-prepared, single-crystalline bismuth ferrite nanoparticles show strong size-dependent magnetic properties that correlate with: (a) increased suppression of the known spiral spin structure (period length of approximately 62 nm) with decreasing nanoparticle size and (b) uncompensated spins and strain anisotropies at the surface. Zero-field-cooled and field-cooled magnetization curves exhibit spin-glass freezing behavior due to a complex interplay between finite size effects, interparticle interactions, and a random distribution of anisotropy axes in our nanoparticle assemblies. 相似文献
286.
Tsiliki G Zervakis M Ioannou M Sanidas E Stathopoulos E Potamias G Tsiknakis M Kafetzopoulos D 《IEEE transactions on information technology in biomedicine》2011,15(6):806-812
An increasing number of studies have profiled gene expressions in tumor specimens using distinct microarray platforms and analysis techniques. One challenging task is to develop robust statistical models in order to integrate multi-platform findings. We compare some methodologies on the field with respect to estrogen receptor (ER) status, and focus on a unified-among-platforms scale implemented by Shen et al. in 2004, which is based on a Bayesian mixture model. Under this scale, we study the ER intensity similarities between four breast cancer datasets derived from various platforms. We evaluate our results with an independent dataset in terms of ER sample classification, given the derived gene ER signatures of the integrated data. We found that integrated multi-platform gene signatures and fold-change variability similarities between different platform measurements can assist the statistical analysis of independent microarray datasets in terms of ER classification. 相似文献
287.
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289.
Christos Michalakelis Georgia Dede Dimitris Varoutas Thomas Sphicopoulos 《Telecommunication Systems》2008,39(1):51-60
New product diffusion process studies focus mainly on estimating the adoption rate of the product, within the boundaries of the targeted market. However, and especially for high technology and telecommunications products, it is very likely the case that products or services are introduced simultaneously into a number of market segments, a fact that it is rarely taken into account. Thus, the effect of market and population interaction, and the consequent co-influence in the diffusion rates is not considered. This work focuses on developing and evaluating a pertinent methodology, so as to capture this cross-national interaction influence in the diffusion process. 相似文献