Error Rate Analysis of GF(q) Network Coded Detect-and-Forward Wireless Relay Networks Using Equivalent Relay Channel Models

This paper investigates simple means of analyzing the error rate performance of a general q-ary Galois Field network coded detect-and-forward cooperative relay network with known relay error statistics at the destination. Equivalent relay channels are used in obtaining an approximate error rate of the relay network, from which the diversity order is found. Error rate analyses using equivalent relay channel models are shown to be closely matched with simulation results. Using the equivalent relay channels, low complexity receivers are developed whose performances are close to that of the optimal maximum likelihood receiver.Comment: 28 pages, 10 figures. This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

Wireless Network Control with Privacy Using Hybrid ARQ

We consider the problem of resource allocation in a wireless cellular network, in which nodes have both open and private information to be transmitted to the base station over block fading uplink channels. We develop a cross-layer solution, based on hybrid ARQ transmission with incremental redundancy. We provide a scheme that combines power control, flow control, and scheduling in order to maximize a global utility function, subject to the stability of the data queues, an average power constraint, and a constraint on the privacy outage probability. Our scheme is based on the assumption that each node has an estimate of its uplink channel gain at each block, while only the distribution of the cross channel gains is available. We prove that our scheme achieves a utility, arbitrarily close to the maximum achievable utility given the available channel state information

Beamformer Design with Smooth Constraint-Free Approximation in Downlink Cloud Radio Access Networks

It is known that data rates in standard cellular networks are limited due to inter-cell interference. An effective solution of this problem is to use the multi-cell cooperation idea. In Cloud Radio Access Network, which is a candidate solution in 5G and beyond, cooperation is applied by means of central processors (CPs) connected to simple remote radio heads with finite capacity fronthaul links. In this study, we consider a downlink scenario and aim to minimize total power spent by designing beamformers. We consider the case where perfect channel state information is not available in the CP. The original problem includes discontinuous terms with many constraints. We propose a novel method which transforms the problem into a smooth constraint-free form and a solution is found by the gradient descent approach. As a comparison, we consider the optimal method solving an extensive number of convex sub-problems, a known heuristic search algorithm and some sparse solution techniques. Heuristic search methods find a solution by solving a subset of all possible convex sub-problems. Sparse techniques apply some norm approximation ($\ell_0/\ell_1, \ell_0/\ell_2$) or convex approximation to make the objective function more tractable. We also derive a theoretical performance bound in order to observe how far the proposed method performs off the optimal method when running the optimal method is prohibitive due to computational complexity. Detailed simulations show that the performance of the proposed method is close to the optimal one, and it outperforms other methods analyzed.Comment: 18 pages, 12 figures, submitted to IEEE Access in Feb. 03, 2021. It is a revised version of the paper submitted to IEEE Access in Nov. 23, 2020. Revisions were made according to the reviewer comment

A Theoretical Performance Bound for Joint Beamformer Design of Wireless Fronthaul and Access Links in Downlink C-RAN

It is known that data rates in standard cellular networks are limited due to inter-cell interference. An effective solution of this problem is to use the multi-cell cooperation idea. In Cloud Radio Access Network (C-RAN), which is a candidate solution in 5G and future communication networks, cooperation is applied by means of central processors (CPs) connected to simple remote radio heads with finite capacity fronthaul links. In this study, we consider a downlink C-RAN with a wireless fronthaul and aim to minimize total power spent by jointly designing beamformers for fronthaul and access links. We consider the case where perfect channel state information is not available in the CP. We first derive a novel theoretical performance bound for the problem defined. Then we propose four algorithms with different complexities to show the tightness of the bound. The first two algorithms apply successive convex optimizations with semi-definite relaxation idea where other two are adapted from well-known beamforming design methods. The detailed simulations under realistic channel conditions show that as the complexity of the algorithm increases, the corresponding performance becomes closer to the bound.Comment: 30 pages, single column, 11 figures, submitted to Transactions on Wireless Communications in Oct. 20, 2020. Major Revision decision was made in Jan. 16, 2021. After the revision, it will be resubmitted to the same journal until the end of February, 202

Weismann-Netter-Stuhl Syndrome:A family report

Weismann-Netter-Stuhl (WNS) syndrome is a rare skeletal anomaly that affects the diaphyseal part of both the tibiae and fibulae with posterior cortical thickening and anteroposterior bowing. This anomaly is usually bilateral and symmetrical. The patients are generally of short stature. In some cases, a family history suggesting genetic transmission of a mutation with an unknown locus has been reported. In this paper we present an infant with WNS syndrome with bilateral involvement of the femur. Similar clinical findings were defined in three other family members

R-410A SOĞUTKANLI SOĞUTMA SİSTEMLERİNDE DİKEY EMİŞ BORUSU ÇAPININ BELİRLENMESİ

Bu çalışmada amaçlanan, soğutma ve ısı pompası sistemlerinde yaygın olarak kullanılan, alternatif bir soğutkanın (R-410A) kullanıldığı buhar sıkıştırmalı soğutma sistemleri için dikey emiş (dönüş) borusu çapının belirlenmesidir. Analiz kapsamında, kompresöre etkili yağ dönüşü sağlanabilmesi amacıyla, minimum akış hızı kriteri dikkate alınmıştır. Soğutkanın emiş borusundaki sıcaklığı, eşdeğer boru uzunluğu ve sistemin kondenser sıcaklığı değerleri değişken olarak seçilmiştir. L tipi bakır boruların farklı iç çap değerlerine göre sistemin soğutma kapasitesi, soğutkan debisi ve soğutkan hızı değerlerinin minimum sınırları belirlenmiştir. Sonuçlar tablo olarak sunulmuştur

University sports students’ serceptions of career value

Bu araştırma, 2010-2011 eğitim-öğretim yılı içerisinde üniversiteler arası Futbol Türkiye Şampiyonası’na katılan takımlardaki sporcu öğrencilerin kariyer değeri algılarını tespit etmek amacıyla yapılmıştır. Örneklem grup final müsabakalarına katılan 8 erkek takımında yer alan 144 sporcu öğrenci ile sınırlıdır. Örneklem grubun görüşlerini belirlemek amacıyla, Aktaş’ın (2004) yüksek lisans çalışması için geliştirdiği ölçek formu kullanılmıştır. Verilerin analizinde, frekans, yüzdelik hesaplamalar, Mann-Whithney U testi ve Kruskal-Wallis H testi kullanılmıştır. Araştırma sonucunda, örneklem grubun eğitim gördükleri üniversite değişkenine göre istatiksel olarak anlamlı farklılık bulunmuştur. Eğitim gördükleri fakülte/yüksekokul, eğitim seviyesi ve yaş değişkenlerine göre ise istatiksel olarak anlamlı farklılık tespit edilmemiştir.The purpose of this research is to observe the career value perceptions of the students that participated in the 2010-2011 Turkey Inter-universities Football Championship. Sample group is limited to the 144 students competing in 8 men's teams in the final. In order to determine views of the sample group a scale form which is developed by Aktaş (2004) for master studies was used. In the analysis of the data, the frequency, percentage calculation, the Mann-Whitney U test and Kruskal-Wallis H test were used. As a result of the research, a statistically significant difference was found according to the university in which the sample group train. According to the variables of faculty/high school in which they are being educated, their level of education and age, no statistically significant differences were determined

Dynamic content updates in heterogeneous wireless networks

Content storage at the network edge is a promising solution to mitigate the excessive traffic load due to on-demand streaming applications as well as to reduce the streaming delay. To this end, cache-enabled cellular architectures can be utilized to increase the provided quality-of-service (QoS) and to reduce the network cost. However, there are certain issues to be considered in the design of the content storage strategy such that the contents should be refreshed in order to responds user`s expectations. Using a frequent cache refreshment strategy the ratio of satisfied users can be increased at an increasing network cost. In this paper, we introduce a cache refreshment strategy via leveraging learning techniques so that users' tolerance to the age of content is learned and the content is refreshed accordingly

Plasma antioxidant responses and oxidative stress following a 20 meter shuttle run test in female volleyball players

The effect of physical exercise on oxidant stress and antioxidants has been investigated extensively in the last twenty years. Cells continuously produce free radicals under normal conditions during mitochondrial electron transport chain (ETC). Experimental studies have shown elevated metabolic rate by strenuous physical exercise induces oxidative stress and production of excessive amounts of free radicals. Lipid peroxidation occurs when free radicals react with cellular components involving polyunsaturated fatty acid residues of phospholipids which are very sensitive to oxidation. This study aimed to determine plasma antioxidant responses and oxidative stress following a 20 meter shuttle run test in female volleyball players. Ten female volleyball players from the same team, and ten sedentary female ages between 18-24 years old volunteered to participate in this study. They were in good health and 48 hours before the test did not receive any drug or alcohol. None of them had any endocrine, orthopedic problems. Before the study, Informed, written consent was obtained from all the participants after full explanation of the procedures involved. All procedures were approved by the Selçuk University Meram Medical School of Ethical Committee. 20 meter shuttle run test was designed to estimate the maximal aerobic power of athletes performing in sports with frequent stops and starts (eg. Basketball, volleyball, fencing and so on). Findings of our study demonstrate that in both female groups 20 meter shuttle run test leads to production of more reactive oxygen species than the antioxidant systems can scavenge. Decrease in the activities of these antioxidant enzymes may be due to their inactivation caused by the higher production of the free radicals. it seems that the vulnerability of the body to oxidative stress is significantly enhanced after strenuous exercise test.The effect of physical exercise on oxidant stress and antioxidants has been investigated extensively in the last twenty years. Cells continuously produce free radicals under normal conditions during mitochondrial electron transport chain (ETC). Experimental studies have shown elevated metabolic rate by strenuous physical exercise induces oxidative stress and production of excessive amounts of free radicals. Lipid peroxidation occurs when free radicals react with cellular components involving polyunsaturated fatty acid residues of phospholipids which are very sensitive to oxidation. This study aimed to determine plasma antioxidant responses and oxidative stress following a 20 meter shuttle run test in female volleyball players. Ten female volleyball players from the same team, and ten sedentary female ages between 18-24 years old volunteered to participate in this study. They were in good health and 48 hours before the test did not receive any drug or alcohol. None of them had any endocrine, orthopedic problems. Before the study, Informed, written consent was obtained from all the participants after full explanation of the procedures involved. All procedures were approved by the Selçuk University Meram Medical School of Ethical Committee. 20 meter shuttle run test was designed to estimate the maximal aerobic power of athletes performing in sports with frequent stops and starts (eg. Basketball, volleyball, fencing and so on). Findings of our study demonstrate that in both female groups 20 meter shuttle run test leads to production of more reactive oxygen species than the antioxidant systems can scavenge. Decrease in the activities of these antioxidant enzymes may be due to their inactivation caused by the higher production of the free radicals. it seems that the vulnerability of the body to oxidative stress is significantly enhanced after strenuous exercise test