Global Journal of Technology and Optimization

In this paper we consider the resource-sharing and scheduling problem, with makespan minimization as an objective. Although this problem was optimally solved through a customized branch-and-bound algorithm, its complexity motivated the use of heuristics such as genetic algorithms. A previous genetic algorithm used for solving this problem was significantly faster than the branch-andbound algorithm; however, it suffered from a high rate of infeasible offspring. We propose a new genetic approach, which produces only feasible offspring via a much more compact, genotype representation of the solution. While in the previous genetic algorithm the chromosome consisted of all the solution 0-1 variables (genotype=phenotype), in the new algorithm we define a much smaller chromosome (genotype) that stores sufficient information for efficiently generating a solution for the 0-1 variables (phenotype).

The theory of solving linear and nonlinear ill-posed problems is advanced greatly today (see, e.g., [1,2]). A general scheme for constructing regularizing algorithms using Tikhonov’s variational approach is considered in [2]. It is very well known that ill-posed problems have unpleasant properties even in the cases when stable methods (regularizing algorithms) of their solution exist. E.g., it is impossible to estimate an error of an approximate solution of an illposed problem without very strong assumptions concerning the unknown solution. The following assumptions are under consideration: 1) the unknown solution is an element of the given compact set; 2) the unknown solution is sourcewise represented with a compact operator. For these cases the theory of error estimation or a posteriori error estimation was developed and applied for solving operator equations including integral equations and some inverse problems for differential equations. Numerical methods for solving ill-posed problems and their error estimation are based on convex programming. The results above were used for the solution of practical problems in astrophysics, acoustics, physical chemistry, electron microscopy, nuclear physics, etc.

This paper proposes an augmented Lagrange Hopfield network (ALHN) for solving economic dispatch (ED) problem with ramp rate, emission and transmission constraints. The proposed ALHN method is the continuous Hopfield neural network with its energy function based on augmented Lagrangian function. In ALHN, the energy function is augmented by Hopfield terms from Hopfield neural network and penalty factors from augmented Lagrangian function to damp out oscillation of the Hopfield network during its convergence. Consequently, ALHN can overcome the drawbacks of the conventional Hopfield network due to its simplicity, better optimal solution and faster computing time. The proposed method has been tested on large-scale systems up to 1,200 units and the New England 39-bus system and the obtained results are compared to other methods available in the literature. The test results have shown that the proposed method is more favorable than the others for less total costs and faster computational times.

Robust design is a proven process to achieve insensitivity. From the view point of numerical optimization, the robustness of the objective function makes the system performance insensitive to uncertainties. To better manage the uncertainties, the Taguchi method, reliability-based optimization and robust optimization can be used. This study suggests how to analyze a robust design problem using axiomatic design concept. The design axioms provide a general framework for design methodologies. Two axioms are (1) Independence Axiom and (2) Information Axiom. These axioms can be applied to all design processes in a general way. The first axiom illustrates the relationship between functional requirements (FRs) and design parameters (DPs). Then, the designs of products can be classified into three types: uncoupled, decoupled and coupled. Two goals of robust design can be defined as two functional requirements. One is to reduce the distribution of a response. The other is to set the mean of a response to its target. In general, it is easy to determine the robust solution for a uncoupled or decoupled design. However, the coupled design cannot currently give true robustness, leading to a trade-off between performance and robustness. In this paper, game theory is applied to optimize the trade-off between two functional requirements.

The wireless network technology is increasingly important in healthcare as a result of the aging population and the tendency to acquire chronic disease such as heart attack, high blood pressure amongst the elderly. A wireless sensor network system that has the capability to monitor physiological sign such as SpO₂ (Saturation of Arterial Oxygen) and heart beat rate in real-time from the human’s body is highlighted in this study. This research is to design a prototype sensor network hardware, which consists of microcontroller PIC18F series and transceiver unit. The sensor is corporate into a wearable body sensor network which is small in size and easy to use. The sensor allows a non invasive, real time method to provide information regarding the health of the body. This enables a more efficient and economical means for managing the health care of the population.

A technique is proposed in this paper to acquire and re-construct 3D objects utilizing shadow data. The proposed technique is capable to extract object height features that are not directly visible to the camera scene; however, the technique is only valid to acquire object height information for the directions associated with the incident light and the generated object shadows, hence, acquired height features represents the object features that have actually obstructed the incident light. The technique is tested using objects of different shapes. Close to real measurements are gained using the adopted imaging hardware and setup. The obtained results therefore assure the validity of the suggested approach, hence open the way for further implementation in wider applications.

PIC is a family of Harvard architecture microcontrollers made by Microchip Technology, derived from the PIC1640 originally developed by General Instrument's Microelectronics Division. The name PIC initially referred to "Peripheral Interface Controller". PICs are popular with the developers and the hobbyists due to their low cost, wide availability, large user base, extensive collection of application notes, free development tools, and serial programming (and reprogramming with flash memory) capability. In modern days, PIC microcontrollers are used in the industrial world to control many types of equipment, ranging from consumer to specialized devices. They have replaced older types of controllers, including microprocessors. Also, there is a growing need for off-line support of a computer’s main processor. The demand is going to grow with more equipment uses more intelligence. In the engineering field for instance, PIC has brought a very positive impact in designing an automation control system and controlling industrial machineries. Accordingly, this paper shows the change in the motor speed by the use of PIC in accordance to the light and level of temperature. The project focuses on programming the PIC by embedded software that detects the temperature and light signals and send it to 3 phase induction motor of 240 volt. A theoretical analysis and the practical approach in achieving this work goal have proved that PIC plays an important role in the field of electronics control.

In this paper a sensorless direct torque control (DTC) scheme of permanent magnet synchronous motor (PMSM) is proposed. To improve the performance of the classical DTC a modified control scheme based on twelve sectors instead of six is presented and a comparison between the two methods is carried out. The high performance of the DTC is related to the accuracy of the flux estimation witch is affected by parameter variation especially the stator resistance due changes in temperature or frequency. Therefore, it is adequate to compensate this parameter variation using an online adaptation of the control scheme by the estimated stator resistance using the Extended Kalman Filter (EKF). The EKF is designed to estimate the rotor speed and stator flux and resistance. Estimated parameters are used for the closed loop speed sensorless control operation of the PMSM. It has been demonstrated that the EKF estimation and sensorless DTC perform quite well in spite of the parameters and load variations that handled by the system. The simulation results are presented to validate the effectiveness of the overall control scheme.

Solar energy is rapidly advancing as an important means of renewable energy resource. More energy is produced by tracking the solar panel to remain aligned to the sun at a right angle to the rays of light. This paper describes in detail the design and construction of a prototype for solar tracking system with two degrees of freedom, which detects the sunlight using photocells. The control circuit for the solar tracker is based on a PIC16F84A microcontroller (MCU). This is programmed to detect the sunlight through the photocells and then actuate the motor to position the solar panel where it can receive maximum sunlight.

The increasing penetration of renewable energy sources, the demand for more energy efficient electricity production and the increase in distributed electricity generation causes a shift in the way electricity is produced and consumed. The downside of these changes in the electricity grid is that network stability and controllability becomes more difficult compared to the old situation. The new network has to accommodate various means of production, consumption and buffering and needs to offer control over the energy flows between these three elements. In order to offer such a control mechanism we need to know more about the individual aspects. In this paper we focus on the modelling of distributed production. Especially we look at the use of microCHP (Combined Heat and Power) appliances in a group of houses. The problem of planning the production runs of the microCHP is modelled via an ILP formulation both for a single house and for a group of houses.

The object of the study is to reduce the daily load peaks on an insular electric network (Corsica Island, France) using with help to renewable energy systems. The methodology is based on an energy balance between a PV array, an electrolyzer and fuel cells (50 kW) supplying a seasonal load profile built from electrical network load peaks. This load is supplied firstly by the PV array and the fuel cell produces complementary power when the PV system is deficient. An electrolyzer, using unconsumed PV energy produces hydrogen for the fuel cell. In the present work, at the beginning of the operation, the hydrogen stock is sufficient to satisfy a given number of days corresponding to the system autonomy (Loss of Load probability = 0). Solar and ambient temperature data were measured at our laboratory weather station in Ajaccio (41°55' N, 8°48' E, 70 m altitude). Hourly data are available for the years 1998 to 2004. The originality of this approach was to determine a whole methodology allowing obtaining quickly sizing curves for a PV/H₂ hybrid system supplying a given load (remote sites and/or grid connection).

Sudan is an agricultural country with fertile land, plenty of water resources, livestock, forestry resources and agricultural residues. Energy is one of the key factors for the development of national economies in Sudan. An overview of the energy situation in Sudan is introduced with reference to the end uses and regional distribution. Energy sources are divided into two main types; conventional energy (biomass, petroleum products, and electricity); and non-conventional energy (solar, wind, hydro, etc.). Sudan possesses a relatively high abundance of sunshine, solar radiation and moderate wind speeds, hydro and biomass energy resources. Application of new and renewable sources of energy available in Sudan is now a major issue in the future energy strategic planning for the alternative to the fossil conventional energy to provide part of the local energy demand. Sudan is an important case study in the context of renewable energy. It has a long history of meeting its energy needs through renewables. Sudan’s renewables portfolio is broad and diverse, due in part to the country’s wide range of climates and landscapes. Like many of the African leaders in renewable energy utilisation, Sudan has a well-defined commitment to continue research, development, and implementation of new technologies. Sustainable low-carbon energy scenarios for the new century emphasise the untapped potential of renewable resources. Rural areas of Sudan can benefit from this transition. The increased availability of reliable and efficient energy services stimulates new development alternatives. It is concluded that renewable environmentally friendly energy must be encouraged, promoted, implemented and demonstrated by full-scale plant especially for use in remote rural areas.

The Solid Oxide Fuel Cell (SOFC) is nowadays one of the most promising fuel cell technologies, due to a number of positive features, such as high energy conversion efficiency and fuel flexibility. Nevertheless, the actual technological stage pushes the researchers towards the establishment of specific tools and standards to speed-up the transition to SOFC commercialization into a wide application area, ranging from automotive to marine and airplane Auxiliary Power Units (APUs). Particularly in this work, an overview is given on control-oriented modeling of SOFC at both single cell and stack level. Both numerical results and physical considerations, provided throughout the paper, highlight the importance of developing model-based tools for enhancing design phases, as well as the definition of reliable control and diagnostics strategies for SOFC-APUs.

Photovoltaic (PV) forecast, prospects and barriers (worldwide, Russia and Indonesia) are discussed. A short review of new technologies and projects in VIESH are presented. A new technology of PV modules with life time up to 40-50 years without traditional plastic materials like EVA, Tedlar, Mylar etc. is described. New resonant electric power transmission systems for different power consumers are considered including stationary single-wire waveguide line and single-trolley and contactless high frequency electric transport. Tendencies of integrating solar energy technologies leads to higher output parameters and better service to consumers. Solar PV and PV/T (thermal) concentrator approaches based on tracking and stationary systems with bifacial solar cells are demonstrated. PVT concentrator system with vertical p-n junctions' solar cells is discussed. Advantages and technology of vertical p-n junctions' solar cells are presented. Non expensive solar energy (PV, thermal and PVT, concentrators, heliodon etc.) lab equipment and portable satellite receiver getting space images of Earth and analyzing meteorological information for educational and research purposes are described.