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61.
Cult3D是一个实现基于普通电脑的交互式人体结构三维显示的有效平台。在对内耳结构三维数据处理的基础上,使用Cult3D Designer编辑器,采用组织事件、动作与对象的关联的编程手段实现了对内耳三维对象的复杂交互动作控制,完成基于普通电脑的交互式虚拟内耳显微解剖浏览系统。 相似文献
62.
John Derrick Eerke Boiten Jim Woodcock Joakim von Wright 《Electronic Notes in Theoretical Computer Science》2002,70(3):1-2
This volume contains the Proceedings of the REFINE 2002 workshop. The Workshop was held in Copenhagen, Denmark on July 20 and 21, 2002, as a satellite event to FLoC'02 as an FME-affiliated workshop.Refinement is one of the cornerstones of a formal approach to software engineering. Refinement is the process of developing a more detailed design or implementation from an abstract specification through a sequence of mathematically-based steps that maintain correctness with respect to the original specification.The aim of this BCS FACS refinement workshop was to bring together people who are interested in the development of more concrete designs or executable programs from abstract specifications using formal notations, tool support for formal software development, and practical experience with formal refinement methodologies.The purpose of the workshop was to provide a forum for discussion of common ground and key differences. Topics of interest included:
- • Simulation techniques
- • Foundations and semantics
- • Case studies (specification and verification)
- • Compositional and modular reasoning
- • Object-orientation
- • Time
- • Specification notations
- • Programming models
- • Verification and tool support
- •
- John Derrick<
- jd1@ukc.ac.uk
, University of Kent, UK.
- •
- Eerke Boiten<
- eab2@ukc.ac.uk
, University of Kent, UK.
- •
- Jim Woodcock<
- jcpw@ukc.ac.uk
, University of Kent, UK.
- •
- Joakim von Wright<
- jockum.wright@abo.fi
, Åbo Akademi University, Finland
63.
This paper considers the problem of electing an eventual leader in an asynchronous shared memory system. While this problem
has received a lot of attention in message-passing systems, very few solutions have been proposed for shared memory systems.
As an eventual leader cannot be elected in a pure asynchronous system prone to process crashes, the paper first proposes to
enrich the asynchronous system model with an additional assumption. That assumption (denoted AWB) is particularly weak. It is made up of two complementary parts. More precisely, it requires that, after some time, (1) there
is a process whose write accesses to some shared variables be timely, and (2) the timers of (t−f) other processes be asymptotically well-behaved (t denotes the maximal number of processes that may crash, and f the actual number of process crashes in a run). The asymptotically well-behaved timer notion is a new notion that generalizes and weakens the traditional notion of timers whose durations are required to
monotonically increase when the values they are set to increase (a timer works incorrectly when it expires at arbitrary times,
i.e., independently of the value it has been set to).
The paper then focuses on the design of t-resilient AWB-based eventual leader protocols. “t-resilient” means that each protocol can cope with up to t process crashes (taking t=n−1 provides wait-free protocols, i.e., protocols that can cope with any number of process failures). Two protocols are presented.
The first enjoys the following noteworthy properties: after some time only the elected leader has to write the shared memory,
and all but one shared variables have a bounded domain, be the execution finite or infinite. This protocol is consequently
optimal with respect to the number of processes that have to write the shared memory. The second protocol guarantees that
all the shared variables have a bounded domain. This is obtained at the following additional price: t+1 processes are required to forever write the shared memory. A theorem is proved which states that this price has to be paid
by any protocol that elects an eventual leader in a bounded shared memory model. This second protocol is consequently optimal
with respect to the number of processes that have to write in such a constrained memory model. In a very interesting way,
these protocols show an inherent tradeoff relating the number of processes that have to write the shared memory and the bounded/unbounded
attribute of that memory. 相似文献
64.
快速煅烧分解石灰石对其吸收CO2和SO2的影响 总被引:2,自引:1,他引:1
在加热过程中,应用一种新型的快速加热装置——铂膜反应器,及时准确地获得样品质量和颗粒温度,来研究石灰石的煅烧分解,并对石灰石加热速率高达750℃/s下的分解反应特性,及其对分解后产生的氧化钙吸收CO2和脱硫的化学反应特性进行了研究.实验表明,在初始加热阶段,高升温速率明显阻碍了煅烧分解的进行,这对分解后的CaO吸收CO2的效果影响不大.当加热速率升高时,石灰石分解后产生的CaO吸收CO2和脱硫过程中,钙利用率显著下降. 相似文献
65.
Armando Jiménez Zavala 《电力部件与系统》2014,42(13):1474-1483
Abstract—Time series models provide a powerful tool to extract nonstationary features from measured data. In this article, a statistical framework based upon a dynamic harmonic regression model for examining modal behavior is provided. In this model, temporal patterns in measured data are modeled within a stochastic state space setting. Estimates of the states or time-varying parameters are then obtained using an optimal estimation method based on the Kalman filter. Techniques to estimate future values of the unobserved signal are also analyzed. The widely applicable technique is illustrated on both simulated and measured data. Factors that affect the performance of the method are discussed, including the effects of non-linear trends, data quality, and sampling design. Connections with other modal identification methods are also investigated. 相似文献
66.
67.
Jim Falk Jim Green Gavin Mudd 《The International journal of environmental studies》2013,70(6):845-857
The nuclear debate in Australia is shaped by the nation's substantial base of energy resources, including its large reserves of uranium and recent rises in the market price of uranium. But the debate also echoes Australia's past in the development of programs for nuclear weapons. The proposals include uranium enrichment, the storage of nuclear waste in Australia, and the introduction of nuclear reactors. A national inquiry has been instituted by the government. These developments, stemming from a range of factors, have revived the opposition to uranium mining and nuclear power which has for two decades held a dominant role in Australian politics. The issue of what should be Australia's energy path in a time of climate change is beginning to be examined. The importance of the decisions, whether to be a player in the nuclear club with its attendant multiple hazards, or to play a quite different leadership role in the development and adoption of sustainable energy strategies and technologies, cannot be exaggerated. 相似文献
68.
Carlos H. Caldas Chien‐Cheng Chou Jim O'connor 《Construction Management & Economics》2013,31(10):1079-1090
Highway projects in metropolitan areas often require that adjacent utilities be relocated to accommodate new or expanded highway facilities. Traditionally, utility owners have been responsible for their own relocations prior to highway construction. However, utility relocation delay was reported as one of the root causes of overall project delays in highway construction. In the USA, one strategic approach sporadically taken over the past 15 years by some state departments of transportation (DOTs) has been to combine utility relocation work with the highway contractor's scope of work. While the combined strategy offers many benefits, it does have its own set of challenges and disadvantages. Many of these difficulties involve disagreements between DOTs and utility owners over the appropriateness of the combined strategy for particular types of relocations. Hence, a negotiation‐based decision support model (DSM) for determining whether to use the combined strategy was developed to provide guidance to both DOTs and utility decision makers during the planning and design phases of highways. A literature review and interviews with experts from both DOTs and the utility industry were conducted to identify significant factors as well as their impact levels on the decision. A DSM aiming at synthesizing the factors and orchestrating the negotiation process for the decision was proposed and verified. As suggested by the model evaluators, the proposed DSM can improve the quality of this complex decision‐making process, especially for less experienced project managers or designers. 相似文献
69.
Peter E. D. Love Purnendu Mandal Jim Smith Heng Li 《Construction Management & Economics》2013,31(5):567-574
Rework that is experienced in construction projects is often caused by errors made during the design process. Factors that contribute to design errors are identified and used to design and develop a systems dynamics model, which is used to simulate a number of practical scenarios that can be used to reduce design errors and rework. The model presented in this paper can enable design and project managers to understand better the process of design documentation and how design errors occur in construction projects. 相似文献
70.
The study explored the effects of intensive urbanization on urban plant diversity and landscape pattern. An inventory of plant species in managed green spaces in the nine urban districts of Guangzhou (south China) with varied development history was conducted. The relationships among species richness, diversity and urban development were analysed by community ecology attributes, cluster analysis, growth-form differentiation and district fidelity indices, and statistical tests. The 1055 vascular species were dominated by a small number of common evergreen species, accompanied by many rare species. By species richness, tree was the dominant growth form, followed by herb and shrub. Species richness and diversity were slightly below urban-fringe secondary forests. Old and young districts offered disparate conditions for species enrichment to establish urban landscape patterns with divergent floristic and growth-form assemblages. Urban species profile and vegetation landscapes were mainly influenced by planning and management of the urban landscape and changing landscape fashion. 相似文献