A fuzzy-based optimal reactive power control

A mathematical formulation of the optimal reactive power control problem using fuzzy set theory is presented. The objectives are to minimize real power losses and improve the voltage profile of a given system. Transmission losses are expressed in terms of voltage increments by relating the control variables to the voltage increments in a modified Jacobian matrix. This formulation does not require Jacobian matrix inversion, and hence it will save computation time and memory space. The objective function and the constraints are modeled by fuzzy sets. Linear membership functions of the fuzzy sets are defined and the fuzzy linear optimization problem is formulated. The solution space is defined as the intersection of the fuzzy sets describing the constraints and the objective functions. Each solution is characterized by a parameter that determines the degree of satisfaction with the solution. The optimal solution is the one with the maximum value for the satisfaction parameter. Results for test systems reveal the advantages of the approach     

AI approach to optimal VAr control with fuzzy reactive loads

This paper presents an artificial intelligence (AI) approach to the optimal reactive power (VAr) control problem. The method incorporates the reactive load uncertainty in optimizing the overall system performance. The artificial neural network (ANN) enhanced by fuzzy sets is used to determine the memberships of control variables corresponding to the given load values. A power flow solution determines the corresponding state of the system. Since the resulting system state may not be feasible in real-time, a heuristic method based on the application of sensitivities in an expert system is employed to refine the solution with minimum adjustments of control variables. Test cases and numerical results demonstrate the applicability of the proposed approach. Simplicity, processing speed and ability to model load uncertainties make this approach a viable option for online VAr control     

Delay Mitigation in the Malaysian Construction Industry

This paper describes the importance of applying proper management in dealing with delays in construction for a growing economy. The main objective of this paper is to identify the management tools that are practiced in the local construction industry in mitigating delay. It also aims to identify the main factors that lead to project delays and to suggest recommendations on how to overcome or mitigate effects of the problem. Data is gathered from responses from questionnaire survey and interviews with those involved in construction project. The surveys and research findings indicate that delay incidents occur mainly during the construction phase of a project and one or more parties usually contribute to delay. This paper highlights the importance of having more experienced and capable construction managers as well as skilled laborers to enable the industry to develop at a faster rate either nationally or internationally.     

Direct formation of particles from drops by chemical reaction with gases

The factors which influence the direct formation of solid particles by reaction of sprays with gaseous media were investigated by studying the reaction of single macro-drops of orthophosphoric acid with gaseous ammonia. The composition, temperature and physical nature of the drops were measured or recorded as the reaction proceeded. The controlling resistance for mass-transfer was found to exist within the drop and a diffusion model adequately described the uptake of ammonia for the conditions studied. The maximum uptake of ammonia increased with delay in formation of a permanent solid phase. This delay was increased or altered by (i) reduction in acid concentration, (ii) addition of sulfuric acid, (iii) cyclic exposure of the drop to the gas, and (iv) humidification of the gas.     

Fast and robust three-dimensional best path phase unwrapping algorithm

What we believe to be a novel three-dimensional (3D) phase unwrapping algorithm is proposed to unwrap 3D wrapped-phase volumes. It depends on a quality map to unwrap the most reliable voxels first and the least reliable voxels last. The technique follows a discrete unwrapping path to perform the unwrapping process. The performance of this technique was tested on both simulated and real wrapped-phase maps. And it is found to be robust and fast compared with other 3D phase unwrapping algorithms.     

Development and Testing of a Fluorescent Fiber Solar Concentrator for Remote Daylighting

Conventional solar concentrators and normal luminescent solar concentrators have their difficulties in reticulation and a tracking mechanism is always needed. This article introduces a new design of an optical fiber solar concentrator, which is a 1,200?mm×1,200?mm polymethyl methacrylate plate consisting of 150 pieces of three-color 1-m long Φ2-mm fluorescent fibers. The concentrator is fabricated and is mounted on a university building roof and the concentrated light is transported to a remote dark room through 10-m long Φ2-mm clear optical fibers. A 6-month outdoor testing for its remote indoor daylighting application has been conducted. The reasonable radiation-to-radiation efficiency with a mean value of 0.057, the acceptable lighting effect up to 114.1 lm, and the light-to-light efficiency of 0.58% reveal this fiber solar concentrator a potential in remote indoor daylighting for the application in building integration. The light produced by this device presents a good match to the direct sunlight in color.     

Daylighting can be fluorescent: Development of a fiber solar concentrator and test for its indoor illumination

Many limitations such as the strict dependence on beam irradiation and difficulties for wiring remain in conventional remote daylighting devices. This paper provides a brief discussion on the working theory and limitations for those conventional devices and presents a new concept developed by the first author for remote indoor daylighting. Based on the developed concept, a new device was designed and fabricated accordingly, which is an optical fiber solar concentrator consisting of a PMMA plate and 150 pieces of three-color 1 m long Φ2 mm fluorescent fibers. This new device is mounted on a university building roof and the concentrated light is transported to a remote dark room through 10 m long Φ2 mm clear optical fibers. Outdoor testing and evaluations for remote indoor daylighting and power production have been conducted. A 6-month monitored data from 24th May 2008 to 23rd Nov 2008 has been presented and the results reveal this new device a pleasant potential in remote indoor daylighting for large amount application in building integration.     

The cost of non-conformance during a highway project: a case study

Poor quality resulting from non-conformance during construction leads to extra cost and time to all members of the project team. The costs of rectifying non-conformance can be high and they can affect a firm's profit margin and its competitiveness. Construction-related firms can identify non-conformance information by employing a quality cost matrix as illustrated in a case study as a basis for improvement. Findings indicate the applicability of the matrix, the usefulness of the information for quality improvement and the positive change in attitude of personnel involved in the case study. Areas and frequency of non-conformance and the viability and importance of preventive measures are also ighlighted.     

"Power quality system," a new system of quality management for globalization: towards innovation and competitive advantages.

Knowledge Management (KM) addresses the critical issues of organizational adoption, survival and competence in the face of an increasingly changing environment. KM embodies organizational processes that seek a synergistic combination of the data and information processing capabilities of information and communication technologies (ICT), and the creative and innovative capacity of human beings to improve ICT In that role, knowledge management will improve quality management and avoid or minimize losses and weakness that usually come from poor performance as well as increase the competitive level of the company and its ability to survive in the global marketplace. To achieve quality, all parties including the clients, company consultants, contractors, entrepreneurs, suppliers, and the governing bodies (i.e., all involved stake-holders) need to collaborate and commit to achieving quality. The design based organizations in major business and construction companies have to be quality driven to support healthy growth in today's competitive market. In the march towards vision 2020 and globalization (i.e., the one world community) of many companies, their design based organizations need to have superior quality management and knowledge management to anticipate changes. The implementation of a quality system such as the ISO 9000 Standards, Total Quality Management, or Quality Function Deployment (QFD) focuses the company's resources towards achieving faster and better results in the global market with less cost. To anticipate the needs of the marketplace and clients as the world and technology change, a new system, which we call Power Quality System (PQS), has been designed. PQS is a combination of information and communication technologies (ICT) and the creative and innovative capacity of human beings to meet the challenges of the new world business and to develop high quality products.     

Primary lymphangiomyomatosis with chylous ascites

The structure of the PC-glycan of the major excretory-secretory product (ES-62) of Acanthocheilonema viteae has been investigated using endoglycosidases and lectins. Results obtained raise the possibility that it may be of the high mannose type. This, and the insensitivity of the PC-glycan to treatments which remove PC or choline from bacterial PC-glycans, suggests that it may be more analogous to fungal, than to bacterial PC-containing glycans.