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1.
Today companies face the unprecedented challenges of a global market, collaborative environments and the concept of management of the entire product life cycle. In supporting this, the challenge is not only how to utilize information management policies, but also how to develop product representation methods to meet the new demands including platform/application independence, support for the product lifecycle, assisting generation of viewpoint-specific representations, rapid sharing of information between geographically distributed applications and users, and protection of commercial security (intellectual property). This paper proposes a product representation approach using the strengths of lightweight representation and annotation and markup practices to allow the association of product data from throughout the lifecycle with the geometric form of the product. The approach, called Lightweight Model with Multi-layer Annotation (LIMMA), integrates the concept of lightweight representation with annotation of boundary-representations (b-rep) of a product and the use of a formalised markup language (XML). Examples of annotation layers and development of models through-life are given, based on the LIMMA approach.
Lian DingEmail:
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2.
We use panel data on road sections to investigate the effect of traffic policing on non-urban road accidents in Israel. Traffic policing is measured indirectly by the number of police reports issued for driving offences. Our main findings are: (1) only large-scale enforcement has any measurable effect on road accidents while small-scale enforcement has no apparent effect. (2) The enforcement effect is slightly larger in the long run than it is in the short-run. (3) The effect of enforcement tends to dissipate rapidly after the dosage of enforcement is reduced. (4) Enforcement has no effect on fatal road accidents. (5) The evidence that the effect of policing in one road section spills over onto other road sections is weak.  相似文献   

3.
Today companies face the unprecedented challenges of a global market, collaborative environments and the concept of management of the entire product life cycle. In supporting this, the challenge is not only how to utilize information management policies, but also how to develop product representation methods to meet the new demands including platform/application independence, support for the product lifecycle, assisting generation of viewpoint-specific representations, rapid sharing of information between geographically distributed applications and users, and protection of commercial security (intellectual property). This paper proposes a product representation approach using the strengths of lightweight representation and annotation and markup practices to allow the association of product data from throughout the lifecycle with the geometric form of the product. The approach, called Lightweight Model with Multi-layer Annotation (LIMMA), integrates the concept of lightweight representation with annotation of boundary-representations (b-rep) of a product and the use of a formalised markup language (XML). Examples of annotation layers and development of models through-life are given, based on the LIMMA approach.  相似文献   

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The study deals with the evaluation of the effects of a new deployment of the National Traffic Police in Israel--a concentrated general enforcement on 700 km of interurban roads, which contain 60% of all rural accidents and about half of the severe accident locations. The enforcement project began in April 1997 and lasted for 1 year, aiming at a 10% reduction of severe accidents on those roads. The evaluation study consisted of three main parts: (a) monitoring of everyday police operations on the project roads; (b) periodic evaluation of the project's influence on drivers' behavior and attitudes; and (c) the evaluation of accident changes within the project area, at the end of the project year. Speed measurements, performed before the police project launch, demonstrated that, depending on road type, up to 85% of drivers violated the rural road speed limits. Two rounds of field observations, before and during the project, took place at 32 sites throughout the project area and comprised eight behavior types: turning performance; signaling while turning; compliance with 'stop' and 'yield' signs; safety belt use by drivers and front-seat passengers, at the intersections; 'keeping to the right' on dual carriageway roads; and 'not-crossing of the white separating line' at single carriageway roads. A comparison revealed a general reduction in violation rates of most behaviors, during-the-project, except for compliance with 'stop' signs and signaling. Concurrently, two rounds of driver surveys were performed which examined the project's influence on the drivers' attitudes towards the police enforcement effectiveness and risk connected with traffic rule violations. An improvement was identified in perceived general level of police activity, during the project, whereas a lower or similar risk of apprehension was attributed by drivers to most specific violations of the traffic rules. Three groups of indices of police activity were estimated monthly during the study: inputs; outputs; and efficiency indices, which characterized the police presence on the project roads, the citations produced and the usage rates of the vehicle fleet and the enforcement tools. Analyzing these indices, two periods in the project performance were determined, and three criteria were proposed to subdivide the project roads into two groups, according to the level of enforcement intensity. Both periods and enforcement levels, as well as geographic zone, were accounted for in the analysis of accident trends on the project roads. For the accident analysis, a statistical model combining the odds ratio and longitudinal methods, was developed and applied to the severe accident counts, all injury accidents and severe casualties. A statistically significant reduction in severe accidents and severe casualties, as opposed to the comparison group, was found on the highly enforced roads in the center of the country. At the same time, since the police project began, an increase in accidents was observed on most interurban roads, including the northern parts of the project area. However, it was noted that in four of the five project road groups the mean value of the odds ratio was much less than one. Thus, although the enforcement project did not attain its full purpose, it seemed to be a deterrent factor for the increasing accident trend that appeared that year on the interurban roads. The findings pointed out that the National Traffic Police did not exhaust its potential in the project's performance and needs more flexible enforcement and deployment tactics.  相似文献   

6.
Social aspects of a community may be correlated with driver's involvement in road traffic accidents. This study focused on examining this association in the context of the social capital theory. A survey of 600 Arab drivers living in 19 towns and villages was conducted using a face-to-face interview. Structural equation modeling was applied to explore paths of associations between the model components. Most of the proposed relationships in the path model were found to be significant, where the model explained 37% of the variation. The results indicate that only volunteering and reciprocity have direct correlations with traffic law violations. While the other correlations (except political involvement), were mediated by attitudes toward traffic laws violation.  相似文献   

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The impact of the indigenous design and production of technologically advanced weapons in industrializing states continues to be a subject of great interest and importance. To date, however, studies of this linkage have tended to be highly generalized and simplistic. Most use static models, which assume either that this investment tends to divert scarce resources from the task of “nation building,” or, at the other end of the spectrum, that such production “spills over” into other areas, providing an infrastructure for broader technological and managerial development. In this study, a relatively complex and dynamic model relating military production to economic and technological development is proposed. In examining the case of Israel, it is shown that military production passes through various stages and is composed of separate and usually diverse sectors, from electronics to metallurgy. At each level and for every sector, the type of technology required, and, thus, the investment, risks and the potential for spill-over are different. Although Israel is, in many cases, unusual, nevertheless the generalized model can serve as a basis for the investigation of other cases.  相似文献   

9.
This paper examines the effect of the use of Center High Mounted Stop Lamp (CHMSL) on rear-end accidents, as reflected in Israeli police records from calendar years 1991-2002. The basic analysis, similar to that used in previous CHMSL studies, compares the involvement in accidents of passenger cars of model years 1994-1996 that are equipped with CHMSL with passenger cars of model years 1991-1993 that are not equipped with CHMSL. The number of involvements as the struck vehicle in a rear-end accident was used as the relevant measurement and the number of involvements as the striking vehicle in a rear-end accident was used as the reference measurement. The results yielded an odds ratio of 0.93. The explanation that the CHMSL is responsible for the 7% decrease is intuitively appealing and is consistent with previous findings. However, the strength of this evidence is marginal (p = 0.07). Additional analyses evaluated the model year effect in greater detail, in order to determine whether there exists a change point between 1993 and 1994 as would be expected from a CHMSL effect, or whether the effect is spurious. Detailed analyses were performed on the ratio of struck to striking involvements as well as the rates of involvement of both types. These analyses showed that (1) the chosen reference measurement is an appropriate one, but (2) the 0.93 odds ratio is quite possibly due to other reasons unrelated to the CHMSL, thus further limiting the confidence in CHMSL effectiveness.  相似文献   

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Boundary representation by straight lines and circular arcs is described, and the error introduced through the common representation of circular arc boundaries by quadratic geometrical shape functions is investigated. This error is shown to be in some cases the major contributor to the total error. An even more significant advantage of exact boundary representation is that it permits many of the required integrations to be performed analytically, rather than by using Gaussian quadrature. For example, all integrations in any rectilinear domain can then be evaluated analytically. This generally produces an increase in accuracy, and a saving in the computing time required to assemble the coefficient matrices. In slender domains both this increase in accuracy and saving in computing time are very marked, as analytical integrations permit the use of very much coarser discretization than would be required for numerical quadrature.  相似文献   

13.
分析了基于本体论的上下文建模方法,对现有上下文本体进行了分类和比较,并针对其在时序表示方面存在的问题,提出了基于资源描述框架(RDF)具体化的上下文时序信息表示方法,扩展了上下文本体的描述能力.同时针对上下文感知中的时序推理问题,提出了一个持续时间推理算法;另外还通过整合Allen区间代数和本体推理实现了时序关系推理.最后通过实验验证了上述两种时序推理方法的效率.  相似文献   

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Experienced time study analysts in the United Kingdom and Israel analyzed a series of motion pictures of a simple manual task. Comparison of the analyses of the two groups showed no significant differences between results. Furthermore, none of these men was able to detect partially trained workers or variations in the micro-method. Variations between observers were minimal where the observations concerned a very specific task situation.  相似文献   

16.
The general consensus from epidemiological game-theory studies is that vaccination coverage driven by self-interest (Nash vaccination) is generally lower than group-optimal coverage (utilitarian vaccination). However, diseases that become more severe with age, such as chickenpox, pose an exception to this general consensus. An individual choice to be vaccinated against chickenpox has the potential to harm those not vaccinated by increasing the average age at infection and thus the severity of infection as well as those already vaccinated by increasing the probability of breakthrough infection. To investigate the effects of these externalities on the relationship between Nash and utilitarian vaccination coverages for chickenpox, we developed a game-theory epidemic model that we apply to the USA and Israel, which has different vaccination programmes, vaccination and treatment costs, as well as vaccination coverage levels. We find that the increase in chickenpox severity with age can reverse the typical relationship between utilitarian and Nash vaccination coverages in both the USA and Israel. Our model suggests that to obtain herd immunity of chickenpox vaccination, subsidies or external regulation should be used if vaccination costs are high. By contrast, for low vaccination costs, improving awareness of the vaccine and the potential cost of chickenpox infection is crucial.  相似文献   

17.
四元数方法表示的反射和折射定律   总被引:1,自引:0,他引:1  
在讨论四元数及其基本运算、Rodrigues-Hamilton参数表示的四元数和四元数变换算子的基础上,给出了标准四元数的定义。基于标准四元数,推导了四元数方法表示的光线反射和折射变换算子,并给出了对应的计算公式,为复杂光学系统以及失调光学系统的空间光线传输计算奠定了理论基础。  相似文献   

18.
The present paper extends Lotka’s theorem—which we rename as “the law of limited excellence”—while empirically modelling the scientific productivity of 46 Israel Prize laureates in the life and exact sciences—a group best described as ‘Star Scientists’. By focusing on this highly selective group we expose unequal scientific productivity even amongst Israel’s most prolific scientists. Specifically, we test the invariance of Lotka’s law by focusing attention on the extreme tail of publication distributions while empirically exploring the non-linearity of its seemingly “flat” tail. By exposing the rarity of excellence even in this extreme end of publication productivity we extend the generality of Lotka’s theorem and expose that—like a fractal—the tail of excellence behaves as the entire distribution. We end this empirical contribution by suggesting a few implications for research and policy.  相似文献   

19.
Young drivers in Israel, as in other parts of the world, are at an elevated risk of being involved in car crashes more than any other age group. A Graduated Driver Licensing System (GDL) has been introduced in Israel, requiring new drivers to be accompanied by an experienced driver during the first 3 months after obtaining a driving license. In an effort to ensure the effectiveness of the accompanied driving phase, a novel program which targets both young drivers and their parents, called green light for life (GLL), was initiated. This study aims to determine the effectiveness of GLL by comparing between young drivers who participated in the program and those who did not. Additionally, this study examined a structural equation model to predict young drivers’ involvement in car crashes and additional risk measures. The study utilized quantitative measures through a questionnaire completed by 738 young drivers (437 men, 301 women; 362 of whom participated in the program, 376 who did not). The results obtained indicate that GLL participants showed more positive views regarding the accompanied driving phase and were less involved in car crashes. They draw a comprehensive model of associations between various aspects of accompanied driving and risky driving measures.  相似文献   

20.
The conservation equation for a monochromatic field with arbitrary polarization propagating in an inhomogeneous transparent medium is expressed in terms of amplitude and phase variables. The expressions obtained for linearly polarized fields are compared with the results obtained in the eikonal approximation. The electric field wave equation is written in terms of intensity and phase variables. The transport equations for the irradiance and the phase are shown to be particular cases of these derivations. The conservation equation arising from the second-order differential wave equation is shown to be equivalent to that obtained from Poynting's theorem.  相似文献   

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