Search results for: Standard cells
1301 SPH Method used for Flow Predictions at a Turgo Impulse Turbine: Comparison with Fluent
Authors: Phoevos K. Koukouvinis, John S. Anagnostopoulos, Dimitris E. Papantonis
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This work is an attempt to use the standard Smoothed Particle Hydrodynamics methodology for the simulation of the complex unsteady, free-surface flow in a rotating Turgo impulse water turbine. A comparison of two different geometries was conducted. The SPH method due to its mesh-less nature is capable of capturing the flow features appearing in the turbine, without diffusion at the water/air interface. Furthermore results are compared with a commercial CFD package (Fluent®) and the SPH algorithm proves to be capable of providing similar results, in much less time than the mesh based CFD program. A parametric study was also performed regarding the turbine inlet angle.Keywords: Smoothed Particle Hydrodynamics, Mesh-lessmethods, Impulse turbines, Turgo turbine.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 26411300 Overhead Estimation over Capacity of Mobile WiMAX
Authors: Saeed AL-Rashdy, Qing Guo
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The IEEE802.16 standard which has emerged as Broadband Wireless Access (BWA) technology, promises to deliver high data rate over large areas to a large number of subscribers in the near future. This paper analyze the effect of overheads over capacity of downlink (DL) of orthogonal frequency division multiple access (OFDMA)–based on the IEEE802.16e mobile WiMAX system with and without overheads. The analysis focuses in particular on the impact of Adaptive Modulation and Coding (AMC) as well as deriving an algorithm to determine the maximum numbers of subscribers that each specific WiMAX sector may support. An analytical study of the WiMAX propagation channel by using Cost- 231 Hata Model is presented. Numerical results and discussion estimated by using Matlab to simulate the algorithm for different multi-users parameters.Keywords: BWA, mobile WiMAX, capacity, AMC , overheads.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 20821299 Development of a Vegetation Searching System
Authors: Rattanathip Rattanachai, Kunyanuth Kularbphettong
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This paper describes the development of a Vegetation Searching System based on Web Application in case of Suan Sunandha Rajabhat University. The model was developed by PHP, JavaScript and MySQL database system and it was designed to support searching for endemic and rare species of trees on Web site. We describe the design methods and functional components of this prototype. To evaluate the system performance, questionnaires for the system usability and Black Box Testing were used to measure expert and user satisfaction. The results were satisfactory as followed: Means for experts and users were 4.30 and 4.50, and standard deviation for experts and users were 0.61and 0.73 respectively. Further analysis showed that the quality of the plant searching Website was also at a good level as well.
Keywords: Endemic species, Vegetation, Web based System, and Black Box Testing.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 17921298 Low Computational Image Compression Scheme based on Absolute Moment Block Truncation Coding
Authors: K.Somasundaram, I.Kaspar Raj
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In this paper we have proposed three and two stage still gray scale image compressor based on BTC. In our schemes, we have employed a combination of four techniques to reduce the bit rate. They are quad tree segmentation, bit plane omission, bit plane coding using 32 visual patterns and interpolative bit plane coding. The experimental results show that the proposed schemes achieve an average bit rate of 0.46 bits per pixel (bpp) for standard gray scale images with an average PSNR value of 30.25, which is better than the results from the exiting similar methods based on BTC.Keywords: Bit plane, Block Truncation Coding, Image compression, lossy compression, quad tree segmentation
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 17501297 Hypothesis of a Holistic Treatment of Cancer: Crab Method
Authors: Devasis Ghosh
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The main hindrance to total cure of cancer is a) the failure to control continued production of cancer cells, b) its sustenance and c) its metastasis. This review study has tried to address this issue of total cancer cure in a more innovative way. A 10-pronged “CRAB METHOD”, a novel holistic scientific approach of Cancer treatment has been hypothesized in this paper. Apart from available Chemotherapy, Radiotherapy and Oncosurgery, (which shall not be discussed here), seven other points of interference and treatment has been suggested, i.e. 1. Efficient stress management. 2. Dampening of ATF3 expression. 3. Selective inhibition of Platelet Activity. 4. Modulation of serotonin production, metabolism and 5HT receptor antagonism. 5. Auxin, its anti-proliferative potential and its modulation. 6. Melatonin supplementation because of its oncostatic properties. 7. HDAC Inhibitors especially valproic acid use due to its apoptotic role in many cancers. If all the above stated seven steps are thoroughly taken care of at the time of initial diagnosis of cancer along with the available treatment modalities of Chemotherapy, Radiotherapy and Oncosurgery, then perhaps, the morbidity and mortality rate of cancer may be greatly reduced.Keywords: ATF3 dampening, auxin modulation, cancer, platelet activation, serotonin, stress, valproic acid.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 14451296 Using Data Mining Techniques for Estimating Minimum, Maximum and Average Daily Temperature Values
Authors: S. Kotsiantis, A. Kostoulas, S. Lykoudis, A. Argiriou, K. Menagias
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Estimates of temperature values at a specific time of day, from daytime and daily profiles, are needed for a number of environmental, ecological, agricultural and technical applications, ranging from natural hazards assessments, crop growth forecasting to design of solar energy systems. The scope of this research is to investigate the efficiency of data mining techniques in estimating minimum, maximum and mean temperature values. For this reason, a number of experiments have been conducted with well-known regression algorithms using temperature data from the city of Patras in Greece. The performance of these algorithms has been evaluated using standard statistical indicators, such as Correlation Coefficient, Root Mean Squared Error, etc.
Keywords: regression algorithms, supervised machine learning.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 34181295 A Real-Time Signal Processing Technique for MIDI Generation
Authors: Farshad Arvin, Shyamala Doraisamy
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This paper presents a new hardware interface using a microcontroller which processes audio music signals to standard MIDI data. A technique for processing music signals by extracting note parameters from music signals is described. An algorithm to convert the voice samples for real-time processing without complex calculations is proposed. A high frequency microcontroller as the main processor is deployed to execute the outlined algorithm. The MIDI data generated is transmitted using the EIA-232 protocol. The analyses of data generated show the feasibility of using microcontrollers for real-time MIDI generation hardware interface.Keywords: Signal processing, MIDI, Microcontroller, EIA-232.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 21271294 Trust Enhanced Dynamic Source Routing Protocol for Adhoc Networks
Authors: N. Bhalaji, A. R. Sivaramkrishnan, Sinchan Banerjee, V. Sundar, A. Shanmugam
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Nodes in mobile Ad Hoc Network (MANET) do not rely on a central infrastructure but relay packets originated by other nodes. Mobile ad hoc networks can work properly only if the participating nodes collaborate in routing and forwarding. For individual nodes it might be advantageous not to collaborate, though. In this conceptual paper we propose a new approach based on relationship among the nodes which makes them to cooperate in an Adhoc environment. The trust unit is used to calculate the trust values of each node in the network. The calculated trust values are being used by the relationship estimator to determine the relationship status of nodes. The proposed enhanced protocol was compared with the standard DSR protocol and the results are analyzed using the network simulator-2.Keywords: Reliable Routing, DSR, Grudger, Adhoc network.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 25031293 Biomass and Pigment Production by Monascus during Miniaturized Submerged Culture on Adlay
Authors: Supavej Maniyom, Gerard H. Markx
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Three reactor types were explored and successfully used for pigment production by Monascus: shake flasks, and shaken and stirred miniaturized reactors. Also, the use of dielectric spectroscopy for the on-line measurement of biomass levels was explored. Shake flasks gave good pigment yields, but scale up is difficult, and they cannot be automated. Shaken bioreactors were less successful with pigment production than stirred reactors. Experiments with different impeller speeds in different volumes of liquid in the reactor confirmed that this is most likely due oxygen availability. The availability of oxygen appeared to affect biomass levels less than pigment production; red pigment production in particular needed very high oxygen levels. Dielectric spectroscopy was effectively used to continuously measure biomass levels during the submerged fungal fermentation in the shaken and stirred miniaturized bioreactors, despite the presence of the solid substrate particles. Also, the capacitance signal gave useful information about the viability of the cells in the culture.Keywords: Chinese pearl barley, miniature submerged culture, Monascus pigment, biomass, capacitance.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 27721292 A 3.125Gb/s Clock and Data Recovery Circuit Using 1/4-Rate Technique
Authors: Il-Do Jeong, Hang-Geun Jeong
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This paper describes the design and fabrication of a clock and data recovery circuit (CDR). We propose a new clock and data recovery which is based on a 1/4-rate frequency detector (QRFD). The proposed frequency detector helps reduce the VCO frequency and is thus advantageous for high speed application. The proposed frequency detector can achieve low jitter operation and extend the pull-in range without using the reference clock. The proposed CDR was implemented using a 1/4-rate bang-bang type phase detector (PD) and a ring voltage controlled oscillator (VCO). The CDR circuit has been fabricated in a standard 0.18 CMOS technology. It occupies an active area of 1 x 1 and consumes 90 mW from a single 1.8V supply.
Keywords: Clock and data recovery, 1/4-rate frequency detector, 1/4-rate phase detector.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 29271291 Dimension Reduction of Microarray Data Based on Local Principal Component
Authors: Ali Anaissi, Paul J. Kennedy, Madhu Goyal
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Analysis and visualization of microarraydata is veryassistantfor biologists and clinicians in the field of diagnosis and treatment of patients. It allows Clinicians to better understand the structure of microarray and facilitates understanding gene expression in cells. However, microarray dataset is a complex data set and has thousands of features and a very small number of observations. This very high dimensional data set often contains some noise, non-useful information and a small number of relevant features for disease or genotype. This paper proposes a non-linear dimensionality reduction algorithm Local Principal Component (LPC) which aims to maps high dimensional data to a lower dimensional space. The reduced data represents the most important variables underlying the original data. Experimental results and comparisons are presented to show the quality of the proposed algorithm. Moreover, experiments also show how this algorithm reduces high dimensional data whilst preserving the neighbourhoods of the points in the low dimensional space as in the high dimensional space.
Keywords: Linear Dimension Reduction, Non-Linear Dimension Reduction, Principal Component Analysis, Biologists.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 15741290 Wave Vortex Parameters as an Indicator of Breaking Intensity
Authors: B. Robertson, K. Hall
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The study of the geometric shape of the plunging wave enclosed vortices as a possible indicator for the breaking intensity of ocean waves has been ongoing for almost 50 years with limited success. This paper investigates the validity of using the vortex ratio and vortex angle as methods of predicting breaking intensity. Previously published works on vortex parameters, based on regular wave flume results or solitary wave theory, present contradictory results and conclusions. Through the first complete analysis of field collected irregular wave breaking vortex parameters it is illustrated that the vortex ratio and vortex angle cannot be accurately predicted using standard breaking wave characteristics and hence are not suggested as a possible indicator for breaking intensity.
Keywords: Breaking Wave Measurement, Wave Vortex Parameters, Analytical Techniques, Ocean Remote Sensing.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 17681289 Some Peculiarities of Growth and Functional Activity of Escherichia coli Strain from Probiotic Formula “ASAP“
Authors: Marine A. Balayan, Susanna S. Mirzabekyan, Marine Isajanyan, Zaven S. Pepoyan, Аrmen H. Trchounian, Аstghik Z. Pepoyan, Helena Bujdakova
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It has been shown that pH 7,3 and 37 0C are the optimal condition for the growth of E. coli “ASAP". The cells grow well on Glucose, Lactose, D-Mannitol, D-Sorbitol, (+)-Xylose, L- (+)-Arabinose and Dulcitol. No growth has been observed on Sucrose, Inositol, Phenylalanine, and Tryptophan. The strain is sensitive to a range of antibiotics. The present study has demonstrated that E. coli “ASAP" inhibit the growth of S. enterica ATCC #700931 in vitro. The studies on conjugating activity has revealed no conjugant of E. coli “ASAP" with plasmid strains E. coli G35#59 and S. enterica ATCC #700931. On the other hand, the conjugants with low frequencies were obtained from E. coli “ASAP" with E. coli G35#61, and E. coli “ASAP" with randomly chosen isolate from healthy human gut microflora: E. coli E6. The results of present study have demonstrated improvements in gut microflora condition of patients with different diseases after the administration of “ASAP"
Keywords: E. coli, ASAP, Probiotic formula, gut microflora.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 17701288 Influence of AgNO3 Treatment on the Flavonolignan Production in Cell Suspension Culture of Silybum marianum (L.) Gaertn
Authors: Anna Vildová, H. Hendrychová, J. Kubeš, L. Tůmová
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The abiotic elicitation is one of the methods for increasing the secondary metabolites production in plant tissue cultures and it seems to be more effective than traditional strategies. This study verified the use of silver nitrate as elicitor to enhance flavonolignans and flavonoid taxifolin production in suspension culture of Sylibum marianum (L.) Gaertn. Silver nitrate in various concentrations (5.887.10-3 mol/L, 5.887.10-4 mol/L, 5.887.10-5 mol/L) was used as elicitor. The content of secondary metabolites in cell suspension cultures was determined by high performance liquid chromatography. The samples were taken after 6, 12, 24, 48, 72 and 168 hours of treatment. The highest content of taxifolin production (2.2 mg.g-1) in cell suspension culture of Silybum marianum (L.) Gaertn. was detected after silver nitrate (5.887.10-4 mol/L) treatment and 72 h application. Flavonolignans such as silybinA, silybin B, silydianin, silychristin, isosilybin A, isosilybin B were not produced by cell suspension culture of S. marianum after elicitor treatment. Our results show that the secondarymetabolites could be released from S. marianum cells into the nutrient medium by changed permeability of cell wall.Keywords: Silybum marianum (L.) Gaertn., elicitation, silver nitrate, taxifolin.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 17941287 Optimizing Operation of Photovoltaic System Using Neural Network and Fuzzy Logic
Authors: N. Drir, L. Barazane, M. Loudini
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It is well known that photovoltaic (PV) cells are an attractive source of energy. Abundant and ubiquitous, this source is one of the important renewable energy sources that have been increasing worldwide year by year. However, in the V-P characteristic curve of GPV, there is a maximum point called the maximum power point (MPP) which depends closely on the variation of atmospheric conditions and the rotation of the earth. In fact, such characteristics outputs are nonlinear and change with variations of temperature and irradiation, so we need a controller named maximum power point tracker MPPT to extract the maximum power at the terminals of photovoltaic generator. In this context, the authors propose here to study the modeling of a photovoltaic system and to find an appropriate method for optimizing the operation of the PV generator using two intelligent controllers respectively to track this point. The first one is based on artificial neural networks and the second on fuzzy logic. After the conception and the integration of each controller in the global process, the performances are examined and compared through a series of simulation. These two controller have prove by their results good tracking of the MPPT compare with the other method which are proposed up to now.
Keywords: Maximum power point tracking, neural networks, photovoltaic, P&O.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 19551286 Forecasting the Volatility of Geophysical Time Series with Stochastic Volatility Models
Authors: Maria C. Mariani, Md Al Masum Bhuiyan, Osei K. Tweneboah, Hector G. Huizar
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This work is devoted to the study of modeling geophysical time series. A stochastic technique with time-varying parameters is used to forecast the volatility of data arising in geophysics. In this study, the volatility is defined as a logarithmic first-order autoregressive process. We observe that the inclusion of log-volatility into the time-varying parameter estimation significantly improves forecasting which is facilitated via maximum likelihood estimation. This allows us to conclude that the estimation algorithm for the corresponding one-step-ahead suggested volatility (with ±2 standard prediction errors) is very feasible since it possesses good convergence properties.Keywords: Augmented Dickey Fuller Test, geophysical time series, maximum likelihood estimation, stochastic volatility model.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 8591285 A Novel Method for Areal Surface Roughness Measurement
Authors: Romuald Synak, Wlodzimierz Lipinski, Marcin Pawelczak
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An area-integrating method that uses the technique of total integrated light scatter for evaluating the root mean square height of the surface Sq has been presented in the paper. It is based on the measurement of the scatter power using a flat photodiode integrator rather than an optical sphere or a hemisphere. By this means, one can obtain much less expensive and smaller instruments than traditional ones. Thanks to this, they could find their application for surface control purposes, particularly in small and medium size enterprises. A description of the functioning of the measuring unit as well as the impact caused by different factors on its properties is presented first. Next, results of measurements of the Sq values performed for optical, silicon and metal samples have been shown. It has been also proven that they are in a good agreement with the results obtained using the Ulbricht sphere instrument.
Keywords: ISO 25178 Standard, scatterometry, surface metrology, surface roughness
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 17321284 Decolorization and Phenol Removal of Palm Oil Mill Effluent by Termite-Associated Yeast
Authors: P. Chaijak, M. Lertworapreecha, C. Sukkasem
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A huge of dark color palm oil mill effluent (POME) cannot pass the discharge standard. It has been identified as the major contributor to the pollution load into ground water. Here, lignin-degrading yeast isolated from a termite nest was tested to treat the POME. Its lignin-degrading and decolorizing ability was determined. The result illustrated that Galactomyces sp. was successfully grown in POME. The decolorizing test demonstrated that 40% of Galactomyces sp. could reduce the color of POME (50% v/v) about 74-75% in 5 days without nutrient supplement. The result suggested that G. reessii has a potential to apply for decolorizing the dark wastewater like POME and other industrial wastewaters.Keywords: Decolorization, palm oil mill effluent, ligninolytic enzyme, yeast, termite.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 13231283 Finite Element Method Analysis of Occluded-Ear Simulator and Natural Human Ear Canal
Authors: M. Sasajima, T. Yamaguchi, Y. Hu, Y. Koike
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In this paper, we discuss the propagation of sound in the narrow pathways of an occluded-ear simulator typically used for the measurement of insert-type earphones. The simulator has a standardized frequency response conforming to the international standard (IEC60318-4). In narrow pathways, the speed and phase of sound waves are modified by viscous air damping. In our previous paper, we proposed a new finite element method (FEM) to consider the effects of air viscosity in this type of audio equipment. In this study, we will compare the results from the ear simulator FEM model, and those from a three dimensional human ear canal FEM model made from computed tomography images, with the measured frequency response data from the ear canals of 18 people.
Keywords: Ear simulator, FEM, viscosity, human ear canal.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 11281282 Bank Business Models and The Changes in CEE Countries
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The aim of this article is to assess the existing business models used by the banks operating in the CEE countries in the time period from 2006 till 2011. In order to obtain research results, the authors performed qualitative analysis of the scientific literature on bank business models, which have been grouped into clusters that consist of such components as: 1) capital and reserves; 2) assets; 3) deposits, and 4) loans. In their turn, bank business models have been developed based on the types of core activities of the banks, and have been divided into four groups: Wholesale, Investment, Retail and Universal Banks. Descriptive statistics have been used to analyse the models, determining mean, minimal and maximal values of constituent cluster components, as well as standard deviation. The analysis of the data is based on such bank variable indices as Return on Assets (ROA) and Return on Equity (ROE).Keywords: Banks, Business model, CEE, ROA, ROE.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 18481281 A Numerical Model to Study the Rapid Buffering Approximation near an Open Ca2+ Channel for an Unsteady State Case
Authors: Leena Sharma
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Chemical reaction and diffusion are important phenomena in quantitative neurobiology and biophysics. The knowledge of the dynamics of calcium Ca2+ is very important in cellular physiology because Ca2+ binds to many proteins and regulates their activity and interactions Calcium waves propagate inside cells due to a regenerative mechanism known as calcium-induced calcium release. Buffer-mediated calcium diffusion in the cytosol plays a crucial role in the process. A mathematical model has been developed for calcium waves by assuming the buffers are in equilibrium with calcium i.e., the rapid buffering approximation for a one dimensional unsteady state case. This model incorporates important physical and physiological parameters like dissociation rate, diffusion rate, total buffer concentration and influx. The finite difference method has been employed to predict [Ca2+] and buffer concentration time course regardless of the calcium influx. The comparative studies of the effect of the rapid buffered diffusion and kinetic parameters of the model on the concentration time course have been performed.
Keywords: Calcium Profile, Rapid Buffering Approximation, Influx, Dissociation rate constant.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 18431280 Construction and Performance Characterization of the Looped-Tube Travelling-Wave Thermoacoustic Engine with Ceramic Regenerator
Authors: Abdulrahman S. Abduljalil, Zhibin Yu, Artur J. Jaworski, Lei Shi
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In a travelling wave thermoacoustic device, the regenerator sandwiched between a pair of (hot and cold) heat exchangers constitutes the so-called thermoacoustic core, where the thermoacoustic energy conversion from heat to acoustic power takes place. The temperature gradient along the regenerator caused by the two heat exchangers excites and maintains the acoustic wave in the resonator. The devices are called travelling wave thermoacoustic systems because the phase angle difference between the pressure and velocity oscillation is close to zero in the regenerator. This paper presents the construction and testing of a thermoacoustic engine equipped with a ceramic regenerator, made from a ceramic material that is usually used as catalyst substrate in vehicles- exhaust systems, with fine square channels (900 cells per square inch). The testing includes the onset temperature difference (minimum temperature difference required to start the acoustic oscillation in an engine), the acoustic power output, thermal efficiency and the temperature profile along the regenerator.Keywords: Regenerator, Temperature gradient, Thermoacoustic, Travelling-wave.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 22661279 Mechanical Properties of Particle Boards from Maize Cob and Urea-Formaldehyde Resin
Authors: A. Danladi, I. O. Patrick
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Particle boards were prepared from Maize cob (MC) and urea-formaldehyde resin (UFR) on compression moulding machine. The amount of MC was varied from 50-120g while 30g of UFR was kept constant. Some mechanical properties of the particle boards were tested using the standard ASM methods. The results show that as the MC content increased from 50- 120g in 30g UFR, the hardness increased from about 6.89 x 102 to7.51 x 102MPa. Impact strength decreased from 3.3x 10-2 to 0.45 x 10-2J/M2, while tensile strength initially increased from 2.63 x 102 to 3.14 x 102 MPa as the MC increased from 50 to 60g in 30g UFR, thereafter, it decreased to about 1.35 x 102MPa at 120g in 30g content.
Keywords: Hardness, Impact strength, Maize cob, Tensile strength and Urea-formaldehyde resin.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 44961278 Optical and Structural Properties of a ZnS Buffer Layer Fabricated with Deposition Temperature of RF Magnetron Sputtering System
Authors: Won Song, Bo-Ra Koo, Seok Eui Choi, Yong-Taeg Oh, Dong-Chan Shin
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Optical properties of sputter-deposited ZnS thin films were investigated as potential replacements for CBD(chemical bath deposition) CdS buffer layers in the application of CIGS solar cells. ZnS thin films were fabricated on glass substrates at RT, 150oC, 200oC, and 250oC with 50 sccm Ar gas using an RF magnetron sputtering system. The crystal structure of the thin film is found to be zinc blende (cubic) structure. Lattice parameter of ZnS is slightly larger than CdS on the plane and thus better matched with that of CIGS. Within a 400-800 nm wavelength region, the average transmittance was larger than 75%. When the deposition temperature of the thin film was increased, the blue shift phenomenon was enhanced. Band gap energy of the ZnS thin film tended to increase as the deposition temperature increased. ZnS thin film is a promising material system for the CIGS buffer layer, in terms of ease of processing, low cost, environmental friendliness, higher transparency, and electrical propertiesKeywords: ZnS thin film, Buffer layer, CIGS, Solar cell.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 23981277 Robust H8 Fuzzy Control Design for Nonlinear Two-Time Scale System with Markovian Jumps based on LMI Approach
Authors: Wudhichai Assawinchaichote, Sing Kiong Nguang
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This paper examines the problem of designing a robust H8 state-feedback controller for a class of nonlinear two-time scale systems with Markovian Jumps described by a Takagi-Sugeno (TS) fuzzy model. Based on a linear matrix inequality (LMI) approach, LMI-based sufficient conditions for the uncertain Markovian jump nonlinear two-time scale systems to have an H8 performance are derived. The proposed approach does not involve the separation of states into slow and fast ones and it can be applied not only to standard, but also to nonstandard nonlinear two-time scale systems. A numerical example is provided to illustrate the design developed in this paper.
Keywords: TS fuzzy, Markovian jumps, LMI, two-time scale systems.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 14561276 An Effective Hybrid Genetic Algorithm for Job Shop Scheduling Problem
Authors: Bin Cai, Shilong Wang, Haibo Hu
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The job shop scheduling problem (JSSP) is well known as one of the most difficult combinatorial optimization problems. This paper presents a hybrid genetic algorithm for the JSSP with the objective of minimizing makespan. The efficiency of the genetic algorithm is enhanced by integrating it with a local search method. The chromosome representation of the problem is based on operations. Schedules are constructed using a procedure that generates full active schedules. In each generation, a local search heuristic based on Nowicki and Smutnicki-s neighborhood is applied to improve the solutions. The approach is tested on a set of standard instances taken from the literature and compared with other approaches. The computation results validate the effectiveness of the proposed algorithm.
Keywords: Genetic algorithm, Job shop scheduling problem, Local search, Meta-heuristic algorithm
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 16521275 Using Fractional Factorial Designs for Variable Importance in Random Forest Models
Authors: Ewa. M. Sztendur, Neil T. Diamond
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Random Forests are a powerful classification technique, consisting of a collection of decision trees. One useful feature of Random Forests is the ability to determine the importance of each variable in predicting the outcome. This is done by permuting each variable and computing the change in prediction accuracy before and after the permutation. This variable importance calculation is similar to a one-factor-at a time experiment and therefore is inefficient. In this paper, we use a regular fractional factorial design to determine which variables to permute. Based on the results of the trials in the experiment, we calculate the individual importance of the variables, with improved precision over the standard method. The method is illustrated with a study of student attrition at Monash University.
Keywords: Random Forests, Variable Importance, Fractional Factorial Designs, Student Attrition.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 19971274 Accounting Performance of the Leading Companies in the Construction Sector in Brazil during the Period 2009-2012
Authors: Fabrício José Piacente, Vanessa de Cillos Silva, Thigo Luiz Mello Melato
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The construction industry has been demonstrating increased growth and importance in Brazil’s national economic development. This study aims to evaluate the financial performance of the leading companies in the construction sector in Brazil in the period from 2009 to 2012. An analysis is made of the capital structure, liquidity, and profitability of the six largest companies in the construction sector in Brazil: Brookfield, Cyrela, Gafisa, MRV, PDG and Rossi. The results are then compared with standard industry ratios. It was found that among the companies analyzed, MRV and Cyrela showed the best relative performance in the period under consideration.
Keywords: Accounting ratios, construction, financial performance.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 18931273 Supercompression for Full-HD and 4k-3D (8k)Digital TV Systems
Authors: Mario Mastriani
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In this work, we developed the concept of supercompression, i.e., compression above the compression standard used. In this context, both compression rates are multiplied. In fact, supercompression is based on super-resolution. That is to say, supercompression is a data compression technique that superpose spatial image compression on top of bit-per-pixel compression to achieve very high compression ratios. If the compression ratio is very high, then we use a convolutive mask inside decoder that restores the edges, eliminating the blur. Finally, both, the encoder and the complete decoder are implemented on General-Purpose computation on Graphics Processing Units (GPGPU) cards. Specifically, the mentio-ned mask is coded inside texture memory of a GPGPU.Keywords: General-Purpose computation on Graphics Processing Units, Image Compression, Interpolation, Super-resolution.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 19791272 Identification of Nonlinear Systems Structured by Hammerstein-Wiener Model
Authors: A. Brouri, F. Giri, A. Mkhida, F. Z. Chaoui, A. Elkarkri, M. L. Chhibat
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Standard Hammerstein-Wiener models consist of a linear subsystem sandwiched by two memoryless nonlinearities. The problem of identifying Hammerstein-Wiener systems is addressed in the presence of linear subsystem of structure totally unknown and polynomial input and output nonlinearities. Presently, the system nonlinearities are allowed to be noninvertible. The system identification problem is dealt by developing a two-stage frequency identification method. First, the parameters of system nonlinearities are identified. In the second stage, a frequency approach is designed to estimate the linear subsystem frequency gain. All involved estimators are proved to be consistent.
Keywords: Nonlinear system identification, Hammerstein systems, Wiener systems, frequency identification.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2400