The objective of this study was tointroduce a recursive least squares (RLS) parameter estimatorenhanced by using a neural network (NN) to facilitate the computing of a bit error rate (BER) (error reduction) during channels estimation of a multiple input-multiple output orthogonal frequency division multiplexing (MIMO-OFDM) system over a Rayleigh multipath fading channel.Recursive least square is an efficient approach to neural network training:first, the neural network estimator learns to adapt to the channel variations then it estimates the channel frequency response. Simulation results show that the proposed method has better performance compared to the conventional methods least square (LS) and the original RLS and it is more robust at high speed mobility.
The objective of this paper was to study the laser spot welding process of low carbon steel sheet. The investigations were based on analytical and finite element analyses. The analytical analysis was focused on a consistent set of equations representing interaction of the laser beam with materials. The numerical analysis based on 3-D finite element analysis of heat flow during laser spot welding taken into account the temperature dependence of the physical properties and latent heat of transformations using ANSYS code V.10.0 to simulate the laser welding process. The effect of laser operating parameters on the results of the temperature profile were studied in addition to the effect on thermal stresses and dimensions of the laser w
... Show MoreThe achievements of the art that we know today are questioned in motives that differ from what art knew before, including dramatic artistic transformations, which he called modern art.
In view of the enormity of such a topic, its ramifications and its complexity, it was necessary to confine its subject to the origin of the motives of the transformations of its first pioneers, and then to stand on what resulted from that of the data of vision in composition and drawing exclusively, and through exploration in that, we got to know the vitality of change from the art of its time.
And by examining the ruling contemporary philosophical concepts and their new standards and their epistemological role in contemporary life, since they includ
Out of the search for the truth, the reader of the Holy Qur’an should know the fate of the sorcerers whom Pharaoh threatened when they announced it as pure monotheism in front of seeing the stick as it turned into a clear serpent, when they said: We believe in the Lord of the worlds, the Lord of Moses and Aaron, and the clear promise came to cut and crucify the trunks of palm trees, and they said what they said if Being supplicants to God (May God cause us to die as Muslims), did Pharaoh actually carry out what he promised them?? So we studied that subject from this angle. Because what looms on the horizon of the Holy Qur’an is that there is no one who seeks refuge with God Almighty in times of adversity except that God Almighty has
... Show MoreNathaniel Hawthorne is famous for his psychological and moral themes. He is also famous for using symbolism in presenting his poignant themes of sin and its consequences. This research paper studies the use of symbols in Hawthorne's The House of Seven gables as an example of his general use of symbolism in his novels. The general pattern of Hawthorne's symbolism is that he presents one major symbol that embodies the main idea, and supports it with a number of minor symbols that develop and elucidate it. In The House of the Seven Gables, the major symbol is the house itself, which stands for corruption, evil, and the injustice of the past. This symbol is supported by such secondary symbols as the heart, the fountain, the
... Show MoreThis study aimed to measure digital stress among students at the University of Baghdad and to identify differences in digital stress based on gender (male–female), academic level (first–fourth year), and field of study (scientific–humanities). The study sample consisted of 200 students from the University of Baghdad. The "Digital Stress" scale, developed by the researcher specifically for this study, was applied, and the descriptive-analytical method was adopted. After administering the scale and analyzing the results using appropriate statistical methods, the findings indicated that university students experience a high level of digital stress, while no statistically significant differences were found in digital stress accord
... Show Moreproblem of the research is the decline of the role of urban space with time as an influential system in societal relations. The research aims to define indicators for achieving social interaction in the city, and to determine indicators for achieving integration in the urban space, and to study the relationship between the integration of urban space and community interaction over time. the research assumed that by distinguishing the social interaction space from the urban space and developing urban spaces in order to be truly interactive spaces, this will help us achieve social interaction and build a positive relationship between them, which enables us to achieve integration within the urban spaces leading to social interaction. Because
... Show MoreThis study investigated three aims for the extent of effectiveness of the two systems in educational development of educators. To achieve this, statistical analysis was performed between the two groups that consisted of (26) participants of the electronic teaching method and (38) participants who underwent teaching by the conventional electronic lecture. The results indicated the effectiveness of the “electronic teaching method” and the “electronic lecture method” for learning of the participants in educational development. Also, it indicated the level of equivalence from the aspect of effectiveness of the two methods and at a confidence level of (0.05). This study reached several conclusions, recommendations, and suggestio
... Show MoreHousing finance is considered to be an important and basic element in housing market, so it’s very important to aid individuals and particular institutions to built or buy new housing units.Inadequate finance system for housing is capable of supporting families to fulfill their needs and helping them to buy and built houses represented a big gap between the need to housing units and available stock. The most important finance institutions in Iraq nowa days are the Real Estate Bank and Housing Fund.Althoughthe role played byeach ofthese institutions, but thattheir roleis stilllimited in thehousing financeat the level ofindividuals orinstitutions. the adoption of the real estate Bank and housing fund to the amount allocated by th
... Show MoreIn this work the corrosion behavior of Ti-6Al-4V alloy was studied by using galvanostatic measurements at room temperature in different media which includ sodium chloride (food salt), sodium tartrate (presence in jellies, margarine, and sausage casings,etc.), sodium oxalate (presence in fruits, vegetables,etc.), acetic acid (presence in vinegar), phosphoric acid (presence in drink), sodium carbonate (presence in 7up drink,etc.), and sodium hydroxide in order to compare.
Corrosion parameters were interpreted in th
... Show MoreThis paper studies the effects of stiffeners on shear lag in steel box girders with stiffened flanges. A three-dimensional linear finite element analysis using STAAD.Pro V8i program has been employed to evaluate and determine the actual top flange stress distribution and effective width in steel box girders. The steel plates of the flanges and webs have been modeled by four-node isoparametric shell elements, while the stiffeners have been modeled as beam elements. Different numbers (4, 8, and 15) for the steel stiffeners have been used in this study to establish their effects on the shear lag and longitudinal stresses in the flange. Using stiffeners reduced the magnitude of the top flange longitudinal stresses about 40%, but did
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