Vol. 17 No. 1 (2009)
Articles
Abstract: In this paper, we suggest a method for designing and implementing of multilayer Perceptron (MLP) neural network based on backpropagation (PB) learning algorithm. The method is described using very high speed integrated circuit hardware description language (VHDL), that used in developing the designs of a very large scale integration (VLSI). Firstly artificial neuron with sigmoid activation function has been designed and implemented which is considered as a basic unit of MLP. The MLP network is trained by BP algorithms, in the Matlab environment in order to obtain the ideal parameters of the network. Then hardware implementation of MLP on FPGAs, of types Spartan 3E and Virtex4 is achieved by using integer format and floating point format respectively . A comparison is done between the two arithmetic formats of MLP implementations on FPGAs. Keyword: MLP neural networks , floating-point (FLP) arithmetic, FPGA, VHDL.
Abstract: Abstract Application of Fuzzy Logic (FL) theory to self-tuning PID controller for the reactive power compensation using Synchronous Machine (SM) is investigated in this paper. The measured Power Factor (PF) is adjusted to a required value using FGS based PID controller. If the measured PF is different from the required reference value an error signal is generated. This error signal and change of error are evaluated by FLC to obtain the new constants values for the PID controller that used to drive six-pulse full wave thyristorized rectifier circuit, which can thus control the excitation field voltage. A VAR compensation for the weak bus, with a desired PF, has been applied on the modified IEEE-5 bus sample systems using bifurcation analysis and Q-V sensitivity methods as voltage stability indicator. In this paper, a suitable model of the SM has been presented. Loading and no load conditions in addition to excitation field voltage have been tested. A good agreement between practical and theoretical results has been observed. Simulation results demonstrate that better control performance can be achieved in comparison with Ziegler-Nichols controllers and Kitamori's PID controllers. It has been found that the proposed controller (FGS based PID) provides fast response, flexible, nonlinear gain characteristic and adaptive operation. It is concluded that the reactive power compensation system with a FGS based PID controller of SM is reliable, sensitive, economical, faster, and more efficient with no harmonics. Keywords: Reactive Power Compensation, PID controller, Fuzzy Logic, Fuzzy Gain Scheduling, Voltage Stability, Bifurcation, and Matlab-Simulink.
Abstract: The drastic increase of residential load consumption in recent years result in over loading feeder lines and transformers for the Iraqi northern area distribution system especially in the city of Mosul. Solution for this problem require up to date research study for the Diversity Factor in different parts of the distribution system, also require consumers load study to find the proper solution to stop excess overload in the transformers and the feeders. This paper include the regional survey for samples of consumers representing typical types of different standard of living and energy consumption by distributing questioners contain list of information such as load type in daily use. Also current readings are recorded for the individual consumer and for the transformers and feeders for the months of the year 2006. In addition to those readings of energy consumption is recorded once every two months. The registered readings are used to calculate the Diversity Factor for different loads, also used in conjunction with the list of questioners to find a sample (for different loads) that coincide with the list of questioner for current and energy readings. Resulting in the feasibility of using the sample to know the peak value of current for any consumer not included in the list of questioner and for any new consumer, since it become possible to decide the size of the transformers and feeder lines, then resulting the Diversity Factor to overcome the problem of overloading in any part of the distribution system.
Abstract: Quenching is known as the most critical step in the sequence of heat-treating operations. The objective of quenching is to preserve the solid solution formed at the solution heat-treating temperature, by rapidly cooling to some lower temperature, usually near room temperature. The scope of this study is to construct the forming limit diagram experimentally for aluminum alloy (2024-T3) sheet, as received and after Quenching from solid solution temperature. The results which have been obtained experimentally showed that at (6 hours) after Quenching, there is a considerable effect on the FLC, Quenching increases the FLC at the as received condition in the range of (19-31 %) . الكلمات الدالة: مخطط حد التشكيل ، الإخماد، المعاملة الحرارية المحلولية .
Abstract: Abstract Traveling-wave equation of the semiconductor optical amplifier is solved analytically in order to study the dynamical properties of the power output in terms of the input parameters that can influence its operation of semiconductor optical amplifier. Power output (number of photons) was calculated as a function of carrier density, input signal, and bias current. Material gain is found for the amplifier at different wavelengths of the input signal. The model investigated the population inversion along the waveguide of the amplifier. The model, which is used in this article, is one of many mathematical models that can be found in literature . The design of semiconductor amplifier in order to predict the operational characteristics can be obtained from its model. The simplicity of our model is in its ability to incorporate with any external stimulus on the amplifier directly in the wave equation. Keywords: SOA, Traveling-wave equation , Numerical simulations.
Abstract: The current research concentrates on special objectives in Innovating and applying a network among the Multi-Agents in the Designed Proposed System , by the use of (Oracle) language to produce a new product by using the available potentialities of the company or by cooperating with partners in the future within the concept of the Virtual Manufacturing. Every Agent (user) has its own roles and privileges. The application results indicate that the VM philosophy has been performed efficiently by the use of the Multi–Agents Network which is managed and attains integration by the server Agent that uses the available interfaces as Oracle language capabilities such as DDE, OLE and run–product. Also, The application results have confirmed that there is a possibility to add easily a new client : Hardwarely: by Updating the network and connecting a new client by the use of one of the following oracle tools: - Oracle Net 8 Assistance, - SQL * Net Easy Configuration , , Oracle Net 8 Assistance.lOracle Net 8 Easy Configuration . Softwarely: to the designed system by the use of the Enterprise Manager console as a wizard or through the SQL plus worksheet. Keyword: Virtual Manufacturing, Multi- Agents Network, Oracle Security
Abstract: Abstract The goal behind this research is to highlight on structural systems using shear walls; this approach is widely used in many countries, due to its desired features,. Shear walls are often considered issential in the design of building to resist seismic action. The research includes designing a multi story building according to a specific plan using frame system and other one for the same building using shear walls, then comparing between the two designs to determine the main differences in between the two design. The research focused on the following points: 1. maximum displacement of the two cases. 2. Quantity of concrete for the construction. 3. Reinforcement steel for the construction. 4. Quantity of formwork, and the required duration to implement each system. The results show that Shear Wall System is the best alternative system. Key words : Structural System , Shear Wall , Frame System , Multi Storey Design
Abstract: ِAbstract Video transmission in Wideband Code Division Multiple Access (WCDMA) system has to use compression technique to overcome the channel bandwidth limitation problem. The video compression uses the Variable Length Coded (VLC,s) to obtain high compression. VLC,s is very sensitive to errors in the transmission channel . Many methods are proposed to protect the video stream. This paper proposes a new method using hybrid Discrete Wavelet Transforms (DWT) & Discrete Cosine Transform (DCT) technique to protect the more visually important VLC,s coefficients in video signal and completed by another technique to improve the performance of the video decoder decision at lower values of Signal to Interference Noise Ratio (SINR). Keywords : Video Transmission , WCDMA, Wavelet , Decoder Decision.
Abstract: Abstract This article is concern of physical environment that effects of indivsual behavior whose occupy it. Stress is one of these reflections which integrate by indivsual needs and coping resources. There are few design characteristics that have the potential to challenge human adaptive spatial resources, stress occurs when there is difficult predictability of misaffordances of internal environment. The results of this articles is that the arrangement of boundaries and the openness of the perimeters affect, to the predictability. Key words: stress, predictability, internal environment.
Abstract: Self-compacting concrete (SCC) is a special concrete that does not require vibration for placing and compaction. It is able to flow under its own weight, completely filling formwork and achieving full compaction, even in the presence of congested reinforcement. The hardened concrete is dense, homogeneous and has the same engineering properties and durability as normal vibrated concrete. The use of self-compacting concrete (SCC) is increasing every day in concrete industry due to its improving production techniques. However, mix design methods and testing procedures are still developing. The water/cement ratio and superplasticiser dosages were being one of the main key parameters in proportioning of SCC mixtures. In this study three mixtures with different combinations of water/cement ratio and superplasticiser dosage levels are investigated. Slump flow test is carried out to determine the effect of w/cm and superplasticiser dosages on fresh and hardened properties of SCC that is bleeding, segregation, stability and compressive strength. The results show that when w/cm increased from 0.32 to 0.36, the flowability of SCC increased by 8.0% and 8.6% for superplasticiser dosages 1.8% and 2.2% respectively, and when w/cm increased from 0.36 to 0.4, the flowability of SCC increased to 4.5% and 5.3% for the same levels of superplasticiser dosages. Key words: Bleeding, Flowability, Segregations, Self-Compacting Concrete, Superplasticiser Dosage.
Abstract: Abstract Recent researches indicate that if water is exposed to an intense magnetic field, it is possible to obtain many positive effects on water properties that improve water use in irrigation application. Therefore, a field study has been conducted to evaluate the extent of there positive improvements under sprinkler irrigation. Uniformity of sprinkler irrigation is used as a performance indicator under different pressure heads. The research included experimental work on solid set sprinkler system (single sprinkler type Rain Bird) using rotating sprinkler heads with single nozzle of diameter 5.2mm. The sprinkler was tested under pressures ( 10,12,15,17,20,22) psi. Treatments have been conducted using normal water with 1 to 5 runs. Direct current (DC) magnetic field for magnetizing water is used to magnetize water. Five levels of the DC magnetic flux densities are used (525,603.1,650,1608.5,3016) Gauss. The study has revealed the performance of the sprinkler irrigation system is improved when the magnetized water is used compared to non–magnetized under the same operating and climatologically conditions . The degree of improvement depends on the intensity of the magnetic field used.Under low and very low pressures, the most effective intensity on uniformity was the intensity 1608.5 Gauss . The best performance of the system was achieved at (15) psi with direct magnetic flux density of 1608.5 Gauss. There variables have achieved the highest increase in irrigation uniformity compared with irrigation in normal water which was 24.2 %. Key Words: uniformity of irrigation, magnetized water, sprinkler irrigation.
Abstract: This research investigates the influence of magnetic water on compressive strength and workability (consistence) of concrete. Results show that the compressive strength of concrete samples prepared with magnetic water increases 10-20% more than that of the tap water samples. In the present study, increasing in compressive strength of concrete is achieved when the magnetic strength of water is 1.2 T, and velocity of water current that passes through magnetic field is of 0.71 m/s. It is also found that magnetic water improves the workability (consistency) of fresh concrete. Key words: magnetic water, workability, compressive strength, concrete, Ampere’s Role “
Abstract: Abstract This paper presents an experimental study and analysis for effect of channel slope on straight vertical and skew free overfall for a rectangular channel with different slopes. The relationship between the critical depth and brink depth for both vertical and skew free overfall are found and shown to be influenced by channel slope. The measured discharge from standard weir was compared with calculated discharge from theoretical equation and found that the discharge over skewed model is greater by (21%) from straight vertical, and the error percentage for calculated and measured discharge not exceed (15% and 12%) for skewed and vertical models respectively for all slopes. The discharge coefficient for vertical model is greater by (25%) than skew, relationships between end and critical depths (he/hc) with channel slope for straight vertical and skew free overfall were calculated.
Abstract: Abstract A numerical solution to the frequency equation for the transverse vibration of a beam (Simply Supported with symmetric overhang) is done. It is proposed two limiting cases of a beam with no overhang, and no span. This agrees with the cases in which the supports are at the nodal Points of a freely vibrating beam. Also the numerical results compared with the analytical solutions for this study are coincident. An approximation to the solution of the frequency equation for beams with small overhang is presented and compared with the numerical solution. This approximation is quite useful to determine a beam’s flexural stiffness (EI), or modulus of elasticity (E), by free vibrating of a simply supported beam. Key word : Transverse vibration, beam, frequency
Abstract: In this research , the meteorological phenomenons ( the rainfall , monthly evaporation , min. & max. temperature , wind velocity and the percentage humidity ) for the following stations (Mosul , Sinjar , Rabeaa , Telafer , Erbil and Salahaldin ) in the north of Iraq were studied using simple correlation between stations . The result of analysis indicated a good correlation in some stations . Also multiple correlation have been applied to study the effect of elevation (E.L.) of station above m.s.l. and a displacement (D), distance from a reference point , (which are Mosul and Telafer ) . Analytical relations were derived for these stations to estimate the missing data and to generalize it for the north part of the country . For simplicity, contour maps were drawn for these three variables E.L. , D, and the value of phenomena is drawn . Key word : climatic phenomenons , M.S.L. & displacement , contour maps .