A vertex υ in a set S is said to be cost effective if it is adjacent to at least as many vertices in V\S as it is in S and is very cost effective if it is adjacent to more vertices in V\S than to vertices in S. A dominating set S is (very) cost effective if every vertex in S is (very) cost effective. The minimum cardinality of a (very) cost effective dominating set of G is the (very) cost effective domination number of G. Our main results include a quadratic upper bound on the very cost effective domination number of a graph in terms of its domination number. The proof of this result gives a linear upper bound for hereditarily sparse graphs which include trees. We show that no such linear bound exists for graphs in general, even when restricted to bipartite graphs. Further, we characterize the extremal trees attaining the bound. Noting that the very cost effective domination number is bounded below by the domination number, we show that every value of the very cost effective domination number between these lower and upper bounds for trees is realizable. Similar results are given for the cost effective domination number.

For a graph G=(V, E) and a set of vertices S⊆ V, a vertex v∈S is said to be very cost effective if it is adjacent to more vertices in V{set minus}. S than in S. A bipartition π= {S, V{set minus}. S} is called very cost effective if both S and V{set minus}. S are very cost effective sets. Not all graphs have a very cost effective bipartition, for example, the complete graphs of odd order do not. We characterize the cactus graphs having a very cost effective bipartition. Also, we show that if a graph G or H has a very cost effective bipartition, then so does the Cartesian product G□ H.

The document most frequently used to support a water resource project's economic feasibility is the commercial benefit-cost analysis, which quantifies tangible and direct project consequences. The objective of this type of analysis is simply to maximize net monetary benefits. This analysis assigns an arbitrary monetary value to ecological and social disruptions, if it does not ignore these effects entirely. An improvement on this method is the social benefit-cost analysis, which assesses sane intangible costs such as air and noise pollution. Unfortunately, even the social analysis usually neglects the sometimes profound effects that a large water resource project has upon quality of life, particularly with regards to massive relocations. The purpose of this dissertation is to resolve these problems by presenting a method by which a water resource study team may use five unique viewpoints - technical, organizational, personal, social, and environmental - to quantify and compare the true benefits and costs of project construction and operation. The study team begins by rigorously documenting the three general categories of project consequence (economic, social and environmental) and assigning each benefit or cost a relative value within category according to perceived positive or negative effects. The second step is to use these quantifications to produce three impact vs. dam height curves. The final and most difficult step in this study process is to assign a relative weight to the respective economic, social, and enviromental impact clusters, depending on national priorities and the biases and personal viewpoints of the decisiomaker (s). The final product of this procedure is a single curve which is used to further investigate and assess the overall feasibility of a water resource project and the 'optimum' range of dam heights. All of the possible impacts of a large water resource project, whether they be tangible or intangible, should be investigated in order to produce an authentic indicator of project efficiency. The only way to insure that all impacts are properly accounted for is to perform an exhaustive examination of a water resource project from the five perspectives mentioned above. The body of this dissertation is an example analysis based upon the proposed Three Gorge Dam and Reservoir on the Yangtze River in the People's Republic of China. This project will be the world's largest power plant at 13,000 megawatts. Because of its size, anticipated impacts, and the interest it has generated all over the world, the Three Gorge project is considered the ideal subject of a comprehensive multiple perspective analysis as described in this study.

The purpose of this research was to understand cost containment strategies used by private hospitals under managed care plans and their relationship to quality of care within the South African environment. The data was collected using a questionnaire consisting of closed questions requesting respondents to rate statements about costs and quality of care, as well as open questions for additional information about costs and quality of care. The study found that managed care has the ability to control costs and that hospitals monitor LOS and prescribe generic medication in order to control costs. The study also found that cost control strategies have a negative impact on quality of care and that hospitals place more emphasis on cost control than quality of care. In addition, large hospitals that enjoy high occupancy rates experienced an increase in patient complaints since the introduction of managed care, compared to small and medium hospitals. The study found that managed care has had a better than average impact on controlling costs and a better than average impact in quality reduction, however the correlation between cost control and quality reduction was negative. Finally, the study found that technology has an impact on rising healthcare costs and that any constraints placed on rising costs associated with technology will have a negative impact on quality of care. Copyright / Dissertation (MBA)--University of Pretoria, 2010. / Gordon Institute of Business Science (GIBS) / unrestricted

The Geographic Information System (GIS) is a crucial part of any land navigation system. Autonomous ground vehicles should have access to stored geographic data and the ability to manipulate it for routing purposes. Since there is no human interaction involved in operating these vehicles, data that a human driver would use to make decisions must be stored in the GIS. The data which represent the earth's surface become a series of factors and constraints which translate to friction in terms of mobility. Factors need to be weighted appropriately, but require a sensitivity analysis before designating these weights. Constraints do not require any weight because they represent absolute barriers which cannot be traveled upon. All GIS layers are incorporated into the raster environment, so that an accumulated surfaces can be built on which a least-cost path can be located. The sensitivity analysis allows generation of many routes which can be field tested for the appropriate weight selection for each factor. Ultimately, the entire process would select an optimal path and output closely spaced waypoints which the vehicle can follow. / Master of Science

Query optimization aims to select a query execution plan among all query paths for a given query. The query optimization of traditional relational database management systems (RDBMSs) relies on estimating the cost of the alternative query plans in the query plan search space provided by a cost model. The classic cost model (CCM) may lead the optimizer to choose query plans with poor execution time due to inaccurate cardinality estimations and simplifying assumptions. A learned cost model (LCM) based on machine learning does not rely on such estimations and learns the cost from runtime. While learned cost models are shown to improve the average performance, they may not guarantee that optimal performance will be consistently achieved. In addition, the query plans generated using the LCM may not necessarily outperform the query plans generated with the CCM. This thesis proposes a hybrid approach to solve this problem by striking a balance between the LCM and the CCM. The hybrid model uses the LCM when it is expected to be reliable in selecting a good plan and falls back to the CCM otherwise. The evaluation results of the hybrid model demonstrate promising performance, indicating potential for successful use in future applications.

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Measuring the use of resources in a production process has been a subject under great scrutiny since more than a hundred years ago. Traditionally, costing systems and cost accounting systems have been in charge of such functions in manufacturing corporations. On the other hand, in recent years Lean Manufacturing has become a powerful and popular force for change. A premier tool for process visualization and understanding is Value Stream Mapping, and it focuses primarily in the time dimension of the processes. However, it is clear that the interaction of cost and time is very important. This is felt in everyday occurrences, such as paying interests for credit cards, mortgages and other types of loans. It is intuitive that the longer a certain amount of money is held, the more it costs. Also, if a larger amount of money is held for one day, it will obviously cost more than holding a smaller amount of money. Therefore, cost and time, BOTH, determine the real cost of the use of money. However, this simple perception has not been applied equally to the measurement of manufacturing processes. They usually concentrate on either cost or time, but seldom in both at the same time and their interaction. The Westinghouse corporation formalized the concepts of the Cost-Time Profile in 1993, based on work done there during several decades. Simply put, the Cost-Time Profile measures how much money is invested in the manufacturing process of a product and for how long, creating a chart that presents the accumulated cost at every point in time (Cost-Time Profile) and measuring the area under this curve (Cost-Time Investment), and then using this quantification to measure the bottom line impact. This research has accomplished two main things: the detailed consideration of the Cost-Time Profile (CTP) and the issues and factors that affect it, and the extension of the concepts to the new reality of Extended Enterprises. In a logical sequence, the basic concepts of CTP are defined and presented. Then, the extension of them to Inter-Enterprise environments follows. Successive sections present how to build a CTP and the Inter-Enterprise Cost-Time Profile (IE-CTP), as well as discussing the factors that should be taken into account to bring the IE-CTP to practical applications, such as the effect of batching; the interaction with existing accounting systems; the consideration of direct cost, overhead and profit and the relationships between companies in supply networks to build IE-CTPs. Then the issue of how to improve the results of the Cost-Time Investment (CTI) and CTP is addressed, and schedule optimization models are developed; generic improvement scenarios and lean implementation scenarios are discussed; some simulation studies are presented for cases when this tool has advantages over deterministic tools and an IE-CTP specific software tool is presented. After learning how to improve the CTP and CTI, a discussion about how to use it and implement it is presented, and finally the summary and conclusions close this research report, identifying the contributions presented and leaving open avenues for future research. / Ph. D.