IIUM Engineering Journal
Not a member yet
783 research outputs found
Sort by
CHAOS CONTROL AND SYNCHRONIZATION USING SYNERGETIC CONTROLLER WITH FRACTIONAL AND LINEAR EXTENDED MANIFOLD
Get PDFIn this manuscript, for the first time, a fractional-order manifold in a synergetic approach using a fractional order controller is introduced. Furtheremore, in the synergetic theory a macro variable is expended into a linear combination of state variables. An aim is to increase the convergence rate as well as time response of the whole closed loop system. Quality of the proposed controller is investigated to control and synchronize a nonlinear chaotic Coullet system in comparison with an integer order manifold synergetic controller. The stability of the proposed controller is proven using the Lyapunov method. In this regard stabilizing control effort is yielded. Simulation result confirm convergence of states towards zero. This is achieved through a control effort with fewer oscillations and lower amplitude of signls which confirm feasibility of the control effort in practice.KEYWORDS:Â synergetic control theory; fractional order system; synchronization; nonlinear chaotic Coullet system; chaos contro
INNOVATIONS IN MICRO/NANO PATTERNING USING TOOL-BASED METHODS
Get PDFIn recent years, the trend in miniaturization of products has been pervasive in areas such as information technology, biotechnology, and the environmental and medical industries. Micro/Nano patterning is the key supporting technology that has to be developed to meet the challenges posed by the requirements of product miniaturization and the industrial realization of nanotechnology. Micro/Nano patterning techniques can be carried out by techniquesbased on energy beams or solid cuttingtools (tool-based micro-machining). Tool-based micro/nano patterning is a relatively new area; however, over the lasttwo decades, owing to the predominant trend in miniaturization of products, Micro/Nano patterning using tool-based techniques has become a key supportive technology. The energybeam-based patterning process (electron-beam lithography) hassome limitations due to poor control of 3D structures, low material removal rate and low aspect ratio. Moreover, these processes requirespecial facilities, and the maximum achievable thickness is relatively small. Some of theselimitations can be overcome by a tool-based approach using ultra-precision machine tools and solid tools as cutting elements to produce the micro-features with well-controlled shape and tolerances. These Micro/Nano machining-based patterning techniques have been achieved through a paradigm shift in the ideas and processes of conventional machining. In this paper, an attempt has beenmade to present the recent innovations in tool-based micro/nano patterning processes
IMPLEMENTING NDN USING SDN: A REVIEW ON METHODS AND APPLICATIONS
Get PDFIn recent years many claims about the limitations of todays’ network architecture, its lack of flexibility and ability to response to ongoing changes and increasing users demands. In this regard, new network architectures are proposed. Software Defined Networking (SDN) is one of these new architectures which centralizes the control of network by separating control plane from data plane. This separation leads to intelligence, flexibility and easier control in computer networks. One of the advantages of this framework is the ability to implement and test new protocols and architectures in actual networks without any concern of interruption.Named Data Networking (NDN) is another paradigm for future network architecture. With NDN the network becomes aware of the content that is providing, rather than just transferring it among end-points. NDN attracts researchers’ attention and known as the potential future of networking and internet. Providing NDN functionalities over SDN is an important requirement to enable the innovation and optimization of network resources. In this paper first we describe about SDN and NDN, and then we introduce methods for implementing NDN using SDN. We also point out the advantages and applications of implementing NDN over SDN
NOVEL CONTROL STRATEGY FOR GRID-CONNECTED PHOTOVOLTAIC ARRAY
Get PDFIn this paper, the configuration of the PV generation system, the dynamic model for PV modules and its power electronic interfacing have been presented. A novel control strategy for the DC-DC converter has been developed in order to extract the maximum amount of power from the PV array. Also, a novel control strategy, which is based on d-q rotating reference frame, has been proposed for the DC-AC converter. The simulation results, based on PSCAD/EMTDC, show that the novel control scheme can transfer the DC energy from PV array, compensate the power factor of AC grid and improve the dynamic behavior of grid-connected PV system
A REVIEW ON LOWER APPENDICULAR MUSCULOSKELETAL SYSTEM OF HUMAN BODY
Get PDFRehabilitation engineering plays an important role in designing various autonomous robots to provide better therapeutic exercise to disabled patients. Hence it is necessary to study human musculoskeletal system and also needs to be presented in scientific manner in order to describe and analyze the biomechanics of human body motion. This review focuses on lower appendicular musculoskeletal structure of human body to represent joints and links architectures; to identify muscle attachments and functions; and to illustrate muscle groups which are responsible for a particular joint movement. Firstly, human lower skeletal structure, linking systems, joint mechanisms, and their functions are described with a conceptual representation of joint architecture of human skeleton. This section also represents joints and limbs by comparing with mechanical systems. Characteristics of ligaments and their functions to construct skeletal joints are also discussed briefly in this part. Secondly, the study focuses on muscular system of human lower limbs where muscle structure, functions, roles in moving endoskeleton structure, and supporting mechanisms are presented elaborately. Thirdly, muscle groups are tabulated based on functions that provide mobility to different joints of lower limbs. Finally, for a particular movement action of lower extremity, muscles are also grouped and tabulated to have a better understanding on functions of individual muscle. Basically the study presents an overview of the structure of human lower limbs by characterizing and classifying skeletal and muscular systems.KEYWORDS: Â Musculoskeletal system; Human lower limbs; Muscle groups; Joint motion; Biomechatronics; Rehabilitation
AN EFFICIENT TECHNIQUE FOR RETINAL VESSEL SEGMENTATION AND DENOISING USING MODIFIED ISODATA AND CLAHE
Get PDFRetinal damage caused due to complications of diabetes is known as Diabetic Retinopathy (DR). In this case, the vision is obscured due to the damage of retinal tinny blood vessels of the retina. These tinny blood vessels may cause leakage which affect the vision and can lead to complete blindness. Identification of these new retinal vessels and their structure is essential for analysis of DR. Automatic blood vessels segmentation plays a significant role to assist subsequent automatic methodologies that aid to such analysis. In literature most of the people have used computationally hungry a strong preprocessing steps followed by a simple thresholding and post processing, But in our proposed technique we utilize an arrangement of light pre-processing which consists of Contrast Limited Adaptive Histogram Equalization (CLAHE) for contrast enhancement, a difference image of green channel from its Gaussian blur filtered image to remove local noise or geometrical object, Modified Iterative Self Organizing Data Analysis Technique (MISODATA) for segmentation of vessel and non-vessel pixels based on global and local thresholding, and a strong post processing using region properties (area, eccentricity) to eliminate the unwanted region/segment, non-vessel pixels and noise that never been used to reject misclassified foreground pixels. The strategy is tested on the publically accessible DRIVE (Digital Retinal Images for Vessel Extraction) and STARE (STructured Analysis of the REtina) databases. The performance of proposed technique is assessed comprehensively and the acquired accuracy, robustness, low complexity and high efficiency and very less computational time that make the method an efficient tool for automatic retinal image analysis. Proposed technique perform well as compared to the existing strategies on the online available databases in term of accuracy, sensitivity, specificity, false positive rate, true positive rate and area under receiver operating characteristic (ROC) curve
ENERGY AUDIT OF A TEXTILE MILL – A CASE STUDY
Get PDFThe textile industry plays a pivotal role in Pakistan’s economy. The industry‘s share for overall manufacturing activity is 46%; in the export sector it is 68%; in value addition it is 9% of GDP and in providing employment it is 38%, in addition to the foreign exchange earnings, investment and contribution to the value added industry. In spite of this major contribution, the textile industry is at a severe risk due to hefty increases in energy costs. Keeping in view of these challenges in order to technically support the textile industry, energy audit of a textile mill ihas been carried out and areas of energy wastage are identified with an estimated cost saving of almost Rs. 6.8 million. Finally recommendations are given for cost effective measures for efficient energy usage, estimation of implementation costs and payback periods.KEYWORDS:  energy; audit; loss; consumption; econom
HARMONIC COMPONENTS ESTIMATION IN POWER SYSTEM USING BACTERIAL FORAGING OPTIMIZATION ALGORITHM AND STOCHASTIC GRADIENT ALGORITHM WITH VARIABLE FORGETTING FACTOR
Get PDFIn this paper, a hybrid configuration algorithm called stochastic gradient method with variable forgetting factor (SGVFF) is proposed to better estimate unknown parameters in a power system such as amplitude and phase of harmonics using variable forgetting factor following the bacterial foraging optimization algorithm (BFO). It must be mentioned that harmonic estimation is a nonlinear problem and using linear optimization algorithms for solving this problem reduces the convergence speed. Thus, BFO algorithm is used for initial estimation. In this paper, first, using little information and by applying BFO algorithm in an off-line procedure initial value for SGVFF algorithm is achieved and then SGVFF algorithm is gained in an on-line procedure. In the hybrid algorithm applied in this paper, amplitudes and phases are estimated simultaneously. Simulation results indicate that the proposed method has faster convergence speed, better performance and higher accuracy in a noisy system in comparison with recursive least squares variable forgetting factors algorithm (RLSVFF). This proves the superiority of the proposed method.KEYWORDS:Â Power system harmonic; BFO algorithm; SGVFF method; RLSVFF metho
CO-PRODUCTION OF LACTIC ACID AND ETHANOL USING RHIZOPUS SP. FROM HYDROLYZED INEDIBLE CASSAVA STARCH AND LEAVES
Get PDFProduction of lactic acid and ethanol from inedible cassava starch and leaves was investigated. Prior to fermentation, hydrolysis of the starch and leaves was conducted. Hydrolysis was optimized by manipulating at three levels each four particular factors, namely acid concentration, starch concentration, temperature, and reaction time. Maximum glucose yield of 0.96 g/g was obtained when 2.5% (w/v) of cassava leaves with 2.5% (w/v) of starch was hydrolyzed using 0.20 M of nitric acid at 160oC of temperature for 10 min. The potential of hydrolyzed cassava starch and leaves was then investigated for lactic acid production using fungal Rhizopus sp. The fermentation process was then conducted in shake flask by varying four factors at three levels each. Maximum lactic acid and ethanol yields of 0.95 g/g and 0.52 g/g, respectively, were achieved at different optimum conditions.  Lactic acid production was found to be linked to a decrease in ethanol production. Design Expert v6.0.8 was used to aid in the design of the experiment using Taguchi’s methodology