A hybrid GA–PS–SQP method to solve power system valve-point economic dispatch problems

This study presents a new approach based on a hybrid algorithm consisting of Genetic Algorithm (GA), Pattern Search (PS) and Sequential Quadratic Programming (SQP) techniques to solve the well-known power system Economic dispatch problem (ED). GA is the main optimizer of the algorithm, whereas PS and SQP are used to fine tune the results of GA to increase confidence in the solution. For illustrative purposes, the algorithm has been applied to various test systems to assess its effectiveness. Furthermore, convergence characteristics and robustness of the proposed method have been explored through comparison with results reported in literature. The outcome is very encouraging and suggests that the hybrid GA–PS–SQP algorithm is very efficient in solving power system economic dispatch problem

Requirements Negotiation: Does Consensus Reduce Software Development Cost?

The requirements engineering activities within a software project are known to be critical to the successful production of a correctly functioning system. This is particularly so when considering the varying views of multiple stakeholders. One promising approach for improving the outcome is to introduce formal negotiation. Negotiation is beneficial to identify and to resolve conflicts between stakeholders. Consensus achieved through negotiation represents all key stakeholders’ perspectives and perceptions regarding the system to be developed. The aim of implementing negotiation is to minimize the possibility of introducing defects during the creation of requirements and to decrease later effort required to fix requirements’ defects. This paper answers the question of whether consensus gives positive significant impact to the software project as a whole or not. It presents an approach to estimate the savings from implementing negotiation in the requirements elicitation process. An empirical evaluation study is adopted through a role play experiment to evaluate the benefit of exercising negotiation. The net gain and the return on investment show positive values which suggest that negotiation activities are worth an investment. Based on a return on investment of 197 percent on average, this paper suggests that negotiation is a useful prevention activity to inhibit defects from occurring during the requirements creation process

Performance Evaluation of Multiple Differential Detection for Third Generation Mobile Communication System

Third generation mobile communication system is widely used nowadays. One of its parameter standard, which is QPSK modulation has been adopted by International Telecommunication Union (ITU) to be used in IMT-2000. However, due to amplitude variations introduced in QPSK, a rather robust and reliable data modulation technique, namely the p/4-shift Differential QPSK is proposed. For detection purposes, two types of detectors are evaluated for their performance in AWGN and Rayleigh fading channels.A differential detection technique called multiple differential detection technique which uses maximumlikelihood sequence estimation (MLSE) of the transmitted phases is compared with conventional differential detection which uses symbol-by-symbol detection. By using some of the IMT-2000 standard parameters, the simulation results show that multiple differential detection scheme performs much better than conventional differential detection scheme

Reduced graphene oxide-multiwalled carbon nanotubes hybrid film with low Pt loading as counter electrode for improved photovoltaic performance of dye-sensitised solar cells

In this work, the role of reduced graphene oxide (rGO) with hyperbranched surfactant and its hybridisation with multiwalled carbon nanotubes (MWCNTs) and platinum (Pt) nanoparticles (NPs) as counter electrode (CE) were investigated to determine the photovoltaic performance of dye-sensitised solar cells (DSSCs). Sodium 1,4-is(neopentyloxy)-3-(neopentyloxycarbonyl)- 1,4-dioxobutane-2-sulphonate (TC14) surfactant was utilised as dispersing and stabilising agent in electrochemical exfoliation to synthesise graphene oxide (GO) as initial solution for rGO production prior to its further hybridisation and fabrication as thin film. A chemical reduction process utilising hydrazine hydrate was conducted to produce rGO due to the low temperature process and water-based GO solution. Subsequently, hybrid solution was prepared by mixing 1 wt% MWCNTs into the produced rGO solution. TC14-rGO and TC14-rGO_MWCNTs hybrid solution were transferred into fluorine-doped tin oxide substrate to fabricate thin film by spraying deposition method. Finally, the CE films were prepared by coating with thin Pt NPs. Photoanode film was prepared by a two-step process: hydrothermal growth method to synthesise titanium dioxide nanowires (TiO2 NWs) and subsequent squeegee method to apply TiO2 NPs. According to solar simulator measurement, the highest energy conversion efficiency (η) was achieved by using CE-based TC14-rGO_MWCNTs/Pt (1.553%), with the highest short current density of 4.424 mA/cm2. The highest η was due to the high conductivity of CE hybrid film and the morphology of fabricated TiO2 NWs/TiO2 NPs. Consequently, the dye adsorption was high, and the photovoltaic performance of DSSCs was increased. This result also showed that rGO and rGO_MWCNTs hybrid can be used as considerable potential candidate materials to replace Pt gradually

Design Simulation of Multiple Differential Transceiver at 2.0 GHz for Third Generation Mobile Communication System

Third generation mobile communication system is widely used nowadays. One of its parameter standard, which is QPSK modulation has been adopted by International Telecommunication Union (ITU) to be used in IMT-2000. However, due to amplitude variations introduced in QPSK, a rather robust and reliable data modulation technique, namely the 7c/4-shift Differential QPSK is proposed. For detection purposes, two types of detectors are evaluated for their performance in AWGN and Rayleigh fading channels. A differential detection technique called multiple differential detection technique which uses maximum-likelihood sequence estimation (MLSE) of the transmitted phases is compared with conventional differential detection which uses symbol-bysymbol detection. By using some of the IMT-2000 standard parameters, the simulation results show that multiple differential detection scheme performs much better than conventional differential detection scheme

A Numerical Algorithm for Solving Stiff Ordinary Differential Equations

An advanced method using block backward differentiation formula (BBDF) is introduced with efficient strategy in choosing the step size and order of the method. Variable step and variable order block backward differentiation formula (VSVO-BBDF) approach is applied throughout the numerical computation.The stability regions of the VSVO-BBDFmethod are investigated and presented in distinct graphs.The improved performances in terms of accuracy and computation time are presented in the numerical results with different sets of test problems. Comparisons are made between the proposed method and MATLAB’s suite of ordinary differential equations (ODEs) solvers, namely, ode15s and ode23s

Effect of Inflow and Infiltration in Sewerage System of Residential Area, Kuantan, Pahang

Inflow and infiltration is a phenomenon in sewerage systems that can have negative effects on the environment and human health if not treated properly. Collaboration has been made between Universiti Malaysia Pahang (UMP) and Indah Water Konsortium Sdn. Bhd. (IWK) where the purpose is to evaluate the amount of inflow and infiltration happening in sewerage systems of residential areas in Kuantan. For this part of the study, one sewer pipeline (MH92a–MH92b) was selected at the residential area of Bandar Putra, having a population equivalent of 1694. The method used in this research was the Flowrate method to tabulate data. ISCO 2150 and 4250 Area Velocity Flowmeters were used to measure flow rate data in the sewer pipeline, whereas ISCO 674 Rain Gauge was used to collect rainfall intensity data. Calibration of all the equipment was done at the Hydrology and Hydraulic Laboratory in UMP. The data was collected for 41 days with each measurement separated by an interval of five minutes. The result shows that the average percentage Infiltration Rate of Qpeak and Qave in this residential catchment were 10.3% and 26.5% which is higher than the value mentioned in Hammer and Hammer (2012). Inflow and infiltration is a real concern, so more study is required to determine whether revision of the infiltration rate recommended in the Malaysian Standard is needed

A study of geo-polymer as alternative material in automotive brake pad

Todays, there are various of alternative materials that have been studied by many researchers in order to find the appropriate combination of brake pad manufacturing in the automotive industry. Some of the alternative materials that has being used including palm slag, banana peels, nutshell and others. This provide more economical benefit and also environmental preservation by utilizing the waste of natural fiber. In this study, geo-polymer brake pad has been prepare using the waste product which is barren soil. Barren soil is chosen as an alternative brake pad material candidate from natural resources as it consists of deserts, dry salt flats, beaches, sand dunes, exposed rock, strip mines, quaries, and gravel pits. This barren soil are mixed with another candidates such as binder, reinforcement, abrasives and lubricant following the standard formulation of brake pad manufacturing. In this works, three type of samples have been used. The elemental composition for sample 1, 2 and 3 are main content with 10%, 5%, 15% alumina and 10%, 15%, 5% graphite respectively. The physical properties of geo-polymer brake pads studied including hardness test and its morphology structure. Sample has been characterized based on two main parameters which are hardness test and morphology analysis. From the analysis, it was found that a prototype from sample 3 exhibit the highest hardness index compare to sample 1 and 2. Sample 3 hardness also much better compare to the conventional brake pad with 64% of the hardness increment. This finding also support by the morphological analysis, whereby the surface of sample 3 show a compact and flat surface with less cracking and porosity. From both parameter, it can be concluded that sample 3 has a great potential to become a suitable geo-polymer brake pad. Here, the composition of a combination alumina and graphite in all sample play as important role in enhance the hardness parameter for the potential brake pad prototype