The aim and objective of this research is to formulate and solve a multi-objective optimization problem for the optimal placement of multiple rows and multiple columns of fixed flat-plate solar collectors in a field. This is to maximize energy collected from the solar collectors and minimize the investment in terms of the field and collector cost. The resulting multi-objective optimization problem will be solved using genetic algorithm techniques. It is necessary to consider multiple columns of collectors as this can result in obtaining higher amounts of energy from these collectors when costs and maintenance or replacement of damaged parts are concerned. The formulation of such a problem is dependent on several factors, which include shading of collectors, inclination of collectors, distance between the collectors, latitude of location and the global solar radiation (direct beam and diffuse components). This leads to a multi-objective optimization problem. These kind of problems arise often in nature and can be difficult to solve. However the use of evolutionary algorithm techniques has proven effective in solving these kind of problems. Optimizing the distance between the collector rows, the distance between the collector columns and the collector inclination angle, can increase the amount of energy collected from a field of solar collectors thereby maximizing profit and improving return on investment. In this research, the multi-objective optimization problem is solved using two optimization approaches based on genetic algorithms. The first approach is the weighted sum approach where the multi-objective problem is simplified into a single objective optimization problem while the second approach is finding the Pareto front. / Dissertation (MEng)--University of Pretoria, 2012. / Electrical, Electronic and Computer Engineering / MEng / Unrestricted

The evaluation methods of competitors in figure skating are the key problem of this sport. The 6.0 system of evaluation was in use until the year 2004. In such system referee compares competitors one by one and decides on the rank. The 6.0 system can be described by method of Expert Judgment and/or Group Participation. In year 2004 International Skating Union introduced the new system. In this new system is in the role of the decision maker mainly the competitor not the referee. The competitor chooses elements of his program which maximized the total point benefit. We can find out the point value of every element in SOV -- Scale of Values. Nowadays the skater can decide according to the Decision Making under Multiple Criteria theory, we use Weighted Sum Approach method which is sufficient for our purpose. In this thesis both systems are going to be explained on particular cases and linked with methods of decision making theory.

The work deals with the safety of technological systems and can be divided into two main thematic units. The attention in the first theoretic unit is paid to aspects that affect the safety of technological systems during their technical life. It describes, together with elementary norms and acts solving the products safety, the most important principles for creating and analysing the safety. It clarifies the origin of company’s risk management, part of its quality management, mentions the faults in which products can be found and also describes the failures which have the biggest effect on these faults and of course on the safety too. Attention is further paid to the reliability analysis, as the tool that helps to create the products safety in the pre-manufacturing phase and also to technical diagnostic, as the tool to keep the safety in after-manufacturing phase. The second practical unit arithmetically analyses the safety of two high-voltage transformers. For that it was used the database of real operation numerical values that were gained during diagnostic investigations on these transformers. In addition it describes mentioned diagnostics methods and gives the new procedure for analyse of transformers’ safety by criteria matrix and weighted sum approach. The main contribution of the work can be considered the checkout and the evaluation of this procedure for use in elaboration of high-voltage transformers diagnostic values for analyzing their safety.