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Performance of STBC Based MIMO-OFDM Using Pilot-aided Channel Estimation
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Many studies have been published to address the growing issues in wireless communication systems. Space-Time Block Coding (STBC) is an effective and practical MIMO-OFDM application that can address such issues. It is a powerful tool for increasing wireless performance by coding data symbols and transmitting diversity using several antennas. The most significant challenge is to recover the transmitted signal through a time-varying multipath fading channel and obtain a precise channel estimation to recover the transmitted information symbols. This work considers different pilot patterns for channel estimation and equalization in MIMO-OFDM systems. The pilot patterns fall under two general types: comb and block types, with a proper arrangement suitable to the multiple transmit antennas. The two main channel estimation methods, LS and MMSE, are compared by evaluating performance in terms of Bit Error Rate (BER) to analyze the performance of pilot-aided channel estimation for 2x2 and 4x4 MIMO arrangements utilizing LTE parameters and the effects of modifying different numbers of OFDM subcarriers under different channel models It has been discussed, a 4x4 system performs better than a 2x2 system in terms of BER with an acceptable amount of additional complexity.

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Publication Date
Wed Nov 03 2021
Journal Name
Journal Of Engineering Research
Performance of quadrilateral perforated prestressed concrete rafters
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This study focuses on the behavior of simply supported perforated prestressed concrete rafters (PPCRs) under single midspan monotonic static loading. The experimental program consisted of testing seven specimens; one solid (control) rafter, and six perforated with quadrilateral openings. The main investigated variables are the number and height of the openings. The test findings indicate that, in comparison to the solid rafter, the presence of quadrilateral openings in the PPCRs led to reducing the load capacity by (4.3-36%) and increase the midspan deflection at ultimate by (14.8-33%). Also, increasing the number of concrete posts between openings resulted in increasing the failure load and decreasing the deflection at all stages o

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Publication Date
Mon Feb 19 2018
Journal Name
Al-academy
Performance of the comedian in Moliere plays
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This research aims to study the performance of comedian in the plays of writer Moliere . The problem of research is to answer the following question:      How does comedian Moliere's techniques in a number of his plays and funny acts?   The    research aims at revealing the means used by the comedian in his performance of a comedic character in the number of Moliere plays.                                                 

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Publication Date
Sat Oct 01 2011
Journal Name
Journal Of Engineering
STATIC PERFORMANCE CHARACTERISTICS OF VORTEX RATE SENSOR
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The vortex rate sensor is a fluidic gyroscope with no moving parts and can be used in very difficult
conditions like radiation, high temperature and noise with minimum cost of manufacturing and
maintenance. A vortex rate sensor made of wood has been designed and manufactured to study
theoretically and experimentally its static performance .A rig has been built to carry out the study,
the test carried out with three different air flow rates (100, 150, and 200 l/min).The results show that
the relation between the differential pressure taken from the sensor pickoff points and the angular
velocity of the sensor was linear.The present work involved theoretical and experimental study of
vortex rate sensor static characteri

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Publication Date
Fri Jan 30 2015
Journal Name
Journal Of Madenat Alelem College
Estimation of Liver Enzymes and Total Bilirubin Level in the sera of patients infected with liver hydatid cysts
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This study included 46 patients with liver hydatid cyst diagnosed clinically and surgically. Control group consist of 22 healthy volunteers. The patients were divided according to the size of the cysts into more and less than 5 cm diameter size, 33 and 13, respectively. Also they were divided into primary and secondary hydatid cyst infection, 30 and 16, respectively. Significant increase of GOT, GPT and ALP levels were recorded due to hydatid cyst infection and had direct effect on the liver function, beside an increase in total bilirubin in patients serum compared with the control, also the same occurred in the secondary infection compared with primary infection, patients with> 5 cm showed significant increase in the above levels compared

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Publication Date
Tue Sep 30 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Estimation of the linear dimensional changes of autoclave cured acrylic resin with multiple palatal depths and investment materials
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Background: Dimensional changes of acrylic denture bases after polymerization results in need for further adjustments or even ends with technical failure of the finished dentures. The purpose of this study was to estimate the linear dimensional changes for different palatal depths when using multiple investment materials and polymerization techniques. Materials and methods: Ninety upper complete denture bases were constructed for this study. They were divided into two main groups according to the polymerization methods: conventional water bath and experimental autoclave (short and long cycles). Each main group was further subdivided into three subgroups according to the palatal depth (shallow, medium and deep). Furthermore, for each palatal

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Publication Date
Fri Apr 12 2019
Journal Name
Journal Of Economics And Administrative Sciences
Compare between simex and Quassi-likelihood methods in estimation of regression function in the presence of measurement error
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       In recent years, the attention of researchers has increased of semi-parametric regression models, because it is possible to integrate the parametric and non-parametric regression models in one and then form a regression model has the potential to deal with the cruse of dimensionality in non-parametric models that occurs through the increasing of explanatory variables. Involved in the analysis and then decreasing the accuracy of the estimation. As well as the privilege of this type of model with flexibility in the application field compared to the parametric models which comply with certain conditions such as knowledge of the distribution of errors or the parametric models may

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Publication Date
Mon Jun 25 2018
Journal Name
Oriental Journal Of Chemistry
Advancement and Validation of new Derivatives Spectrophotometric Method for Individual and Simultaneous Estimation of Diclofenac Sodium and Nicotinamide
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Publication Date
Mon Jan 01 2018
Journal Name
Iraqi Journal Of Agricultural Sciences, 2018, 49(2), Pp. 179–187
Estimation of some genetic parameters for grain yield and its components of maize under watered and water stress
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Publication Date
Tue Sep 30 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Digital panoramic estimation of chronological age among Iraqi adult population in relation to morphological variables of canine teeth
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Background: Age determination of skeletal remains is apart of many medico-legal as well as anthropological examination. Many anatomical structures have been studied, but the teeth and their measurements seem to be the most reliable method since teeth represent the most durable and resilient part of the skeleton. This study was undertaken for estimating the chronological age among Iraqi adult subjects based on various morphological variables of canine teeth using digital panoramic radiograph. Material and methods: The sample in the current study consisted of 240 Iraqi patients attending to the dental radiological clinic at College of dentistry/ Babylon University taking panoramic radiographs for different diagnostic purposes, the study samp

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Publication Date
Tue Jun 30 2020
Journal Name
Journal Of Economics And Administrative Sciences
Comparison of weighted estimated method and proposed method (BEMW) for estimation of semi-parametric model under incomplete data
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Generally, statistical methods are used in various fields of science, especially in the research field, in which Statistical analysis is carried out by adopting several techniques, according to the nature of the study and its objectives. One of these techniques is building statistical models, which is done through regression models. This technique is considered one of the most important statistical methods for studying the relationship between a dependent variable, also called (the response variable) and the other variables, called covariate variables. This research describes the estimation of the partial linear regression model, as well as the estimation of the “missing at random” values (MAR). Regarding the

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