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111.
Shawn T. O’Neil Amitabh Chaudhary Danny Z. Chen Haitao Wang 《Journal of Combinatorial Optimization》2013,26(4):621-635
We present theoretical results for large-file distribution on general networks of known topology (known link bandwidths and router locations). We show that the problem of distributing a file in minimum time is NP-hard in this model, and we give an O(logn) approximation algorithm, where n is the number of workstations that require the file. We also characterize our method as optimal amongst the class of “no-link-sharing” algorithms. 相似文献
112.
Edem O. P. Akpan 《生产规划与管理》2013,24(8):775-780
From the available literature, there seems to be no defined approach to resource smoothing exercise except those attempted by Weist (1967, Management Science, 13, B359-B377) and Burgess and Killebrew (1962, Journal of Industrial Engineering, 13, 76-83). The aim of the smoothing exercise is to achieve optimal resource usage by avoiding high peaks and deep valleys in the project resource profile. The general approach has always been to move some activities with floats in the high peak regions to be started at a later date, and as this is done, the valleys will be filled to smooth the resource profile subject of course to time constraint. If this approach is followed as it is, it would be difficult to determine optimality especially when many resources are involved. A cost minimization approach is envisaged in the present study with no limitation on the number of resource inputs. In a situation where the resources are assumed to have the same value, the cost assigned to each of them should be similar. The method follows the general concept but with a difference; cost of the activity in question is considered. The exercise is continued until all the floats are exhausted. The optimum result would then be the one with the minimum cost profile. From examples used for the evaluation, the results obtained are comparable to those of the above two researchers, and some with better results in the majority of cases. 相似文献
113.
In this paper our main objective is to investigate a deterministic inventory production lot-size model with a permissible delay in payment under a restriction. We analyse our deterministic inventory model under a restriction which will be assumed as the average inventory level. In fact we use in our analysis two approaches: the geometric programming approach; and the Lagrange method. Then a comparison between these two approaches is performed, which is our aim. Finally we deduce some previously published works of other researchers as special cases. 相似文献
114.
In this paper we provide a simple method to determine the inventory policy of multiple items having varying holding cost using a geometric programming approach. The varying holding cost is considered to be a continuous function of the order quantity. The EOQ inventory model with constant holding cost and the classical EOQ inventory model without constraints are derived. 相似文献
115.
In this paper the one-machine scheduling problem with the objective of minimizing the mean tardiness subject to maintaining a prescribed number of tardy jobs is analysed. An algorithm for solving this problem is presented. It is proved that the schedule generated by the proposed algorithm is indeed optimal. 相似文献
116.
117.
Yvonne O. Hunter-Johnson Rosemary B. Closson 《Human Resource Development International》2013,16(2):193-208
The training academy of any law enforcement agency serves as the educational platform for personal, professional and academic development of law enforcement officers. It is essential that the training provided is reflective of best practices to enhance learning, curriculum design, educational policies and instructional techniques compatible with the educational orientation of their learners. To this end, it is proposed within this study that the learners' educational orientation be incorporated in the design phase of the ADDIE (Analysis, Design, Development, Implementation and Evaluation) model. In an effort to determine the educational orientation of the participants, the study utilized the Student Orientation Questionnaire (SOQ) to analyse the educational orientation of law enforcement officers and its implication for training. 相似文献
118.
This article addresses the problem of the multiscale importance of road networks, with the aim of helping to establish a more resilient network in the event of a road disruption scenario. A new model for identifying the most important roads is described and applied on a local and regional scale. The work presented here represents a step forward, since it focuses on the interaction between identifying the most important roads in a network that connect people and health services, the specificity of the natural hazards that threaten the normal functioning of the network, and an assessment of the consequences of three real‐world interruptions from a multiscale perspective. The case studies concern three different past events: road interruptions due to a flood, a forest fire, and a mass movement. On the basis of the results obtained, it is possible to establish the roads for which risk management should be a priority. The multiscale perspective shows that in a road interruption the regional system may have the capacity to reorganize itself, although the interruption may have consequences for local dynamics. Coordination between local and regional scales is therefore important. The model proposed here allows for the scaling of emergency response facilities and human and physical resources. It represents an innovative approach to defining priorities, not only in the prevention phase but also in terms of the response to natural disasters, such as awareness of the consequences of road disruption for the rescue services sent out to local communities. 相似文献
119.
Western Canada is experiencing an unprecedented outbreak of the mountain pine beetle (MPB). The MPB has the potential to impact some of Canada's national parks by affecting park ecosystems and the visitor experience. Controls have been initiated in some parks to lessen the impacts and to prevent the beetle from spreading beyond park boundaries. We examine the perception of ecological risk associated with MPB in two of Canada's national parks, the factors affecting perceptions of risk, and the influence of risk judgments on support for controlling MPB outbreaks in national parks. Data were collected using two studies of park visitors: a mail survey in 2003 and an onsite survey in 2005. The MPB was rated as posing a greater risk to the health and productivity of park ecosystems than anthropogenic hazards and other natural disturbance agents. Visitors who were familiar with MPB rated the ecological and visitor experience impacts as negative, unacceptable, and eliciting negative emotion. Knowledge and residency were the most consistent predictors of risk judgments. Of knowledge, risk, and demographic variables, only sex and risk to ecosystem domains influenced support for controlling the MPB in national parks. Implications for managing MPB in national parks, visitor education, and ecological integrity are discussed. 相似文献
120.
梁顺德 《天津大学学报(社会科学版)》1999,(1)
对结构助词“的”的使用规律。从句子、语义、语用三个平面加以考察。“的”的取舍对句法、语义结构关系产生影响时,必须用“的”;对句法、语义结构的改变没有影响时,“的”的取舍由语用上的需要决定。“的”的取舍在句法、语义规则上具有强制性,在语用规则上具有选择性。 相似文献