Television white spaces (TVWSs) refer to the unused part of the spectrum under the very high frequency (VHF) and ultra-high frequency (UHF) bands. TVWS are frequencies under licenced primary users (PUs) that are not being used and are available for secondary users (SUs). There are several ways of implementing TVWS in communications, one of which is the use of TVWS database (TVWSDB). The primary purpose of TVWSDB is to protect PUs from interference with SUs. There are several geolocation databases available for this purpose. However, it is unclear if those databases have the prediction feature that gives TVWSDB the capability of decreasing the number of inquiries from SUs. With this in mind, the authors present a reinforcement learning-based TVWSDB. Reinforcement learning (RL) is a machine learning technique that focuses on what has been done based on mapping situations to actions to obtain the highest reward. The learning process was conducted by trying out the actions to gain the reward instead of being told what to do. The actions may directly affect the rewards and future rewards. Based on the results, this algorithm effectively searched the most optimal channel for the SUs in query with the minimum search duration. This paper presents the advantage of using a machine learning approach in TVWSDB with an accurate and faster-searching capability for the available TVWS channels intended for SUs.
The performance of a condenser in a domestic refrigerator system without wires and a condenser with a novel design consisted of number of loops as elliptical shape is investigated experimentally in this work. The experiment was conducted with a refrigerator designed to work with HFC134a, under no load and with loads of (1.5,3 and 12 liters of water). In particular, the effects of shape change of the condenser were very important in heat transfer enhancement and reduce of the frictional loss as a result of reducing the pressure drop in the condenser. The results shown that compressor work decreases with elliptical condenser about (8.6% to 11.3%), and then the power consumption decreases also. The performance of household refrigerator with
... Show Moreان حـق التنميـة والتطـور مـن احلقـوق التـي طالبـت هبـا املجتمعـات الدوليـة كافـة السـيام بعـد احلــرب العامليــة الثانيــة، ولكــن العقوبــات االقتصاديــة التــي فرضــت عــى العــراق مل تراعــي حقــه يف التنميــة فبعــد ان كان العــراق يتجــه نحــو التقــدم والتطــور يف منطقــة الــرق االوســط عــاد إىل التدهـور والضعـف بسـبب فـرض العقوبـات االقتصاديـة عليـه مـن قبـل املجتمـع الـدويل ، ونظـرا المهي
... Show Moreبعد مرور عام واكثر على ظهور فيروس كورونا والعالم يواجه تسونامي تلك الجائحة التي تكاد تعصف بالوجود البشري برمته لذا اخذت البشرية على عاتقها مواصلة الجهود والابحاث للوصول الى علاج طبي يتم من خلاله مواجهة هذا الفيروس او التقليل من آثاره التي تهدد الحياة البشرية بالموت المباشر دون الاصابة، مما نتج عن تلك الجهود مجموعة من اللقاحات التي تبنتها الشركات العالمية المسؤولة الا ان الضرورة القصوى التي نتجت عنها تلك الل
... Show MoreThis is a contextual study in face and isotope science, and I have made it in one of the terms faces and isotopes, which is the word (bad). Quranic also, and that is at every aspect they mentioned.
The nature of the research required that it be divided into three sections:
The first topic: I singled it out to show the types of contextual connotations.
- The second topic: I singled it out to define the word bad and its meaning.
- The third topic: I devoted it to the study of the word bad and explaining the significance of the Quranic context on the additional meaning and the original meaning.
Conclusion: It mentioned the most important results, which are:
1- The significance of the Quranic context is one of the most impo
يدرس هذا البحث مشكلة اعتماد الجمهور العراقي على الصحف، باعتبارها إحدى وسائل الإعلام التقليدية، في تكوين معلوماته ومعرفته العامة. وهي دراسة وصفية اعتمدت المنهج الوصفي المسحي الذي يصور الظروف أو الاتجاهات الحالية للظاهرة قيد الدراسة ويحاول تفسيرها. استخدم الباحث الاستبانة في المقام الأول كأداة بحث، حيث تم تصميمها وتوزيعها على عينة مكونة من 150 باحثا قصديا من قراء وقراء الصحف. وينتهي الباحث بالنتائج التالية: إ
... Show Moreيتناول البحث الحماية المدنية للمستهلك في المرحلة السابقة على التعاقد الالكتروني
In this work, the effect of vortex shedding on the solar collector performance of the parabolic trough solar collector (PTSC) was estimated experimentally. The effect of structure oscillations due to wind vortex shedding on solar collector performance degradation was estimated. The performance of PTSC is evaluated by using the useful heat gain and the thermal instantaneous efficiency. Experimental work to simulate the vortex shedding excitation was done. The useful heat gain and the thermal efficiency of the parabolic trough collector were calculated from experimental measurements with and without vortex loading. The prototype of the collector was fabricated for this purpose. The effect of vortex shedding at different operation condition
... Show MoreThe rivers are the main source of fresh water for many countries and the great development which is considered as one of the sustainable development elements in its various agricultural, industrial, domestic and environmental fields .The countries of the world seek food security and water security in order to ensure the basic needs of citizens .Because their distribution is uneven in many regions of the world with different human needs, which leads to conflicts over water sources, especially those located in one international river basin .This has led to the emergence of internationallegal rules governing the management of The problem revolves around the dialectic between limited water resources and increased need for water use b
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The aim of the research is to demonstrate the impact of the salary localization service in enhancing banking competitive advantage. In order to achieve this goal, salary localization was chosen as an independent variable and its impact was studied on the dependent variable, which is the competitive advantage. The research problem lies in the fluctuation of the salary localization service from one bank to another and the impact of this on the competitive advantage. The study sample included five private Iraqi banks, namely (the National Bank of Iraq, the International Development Bank, Assyria International Bank, Al Khaleej Commercial Ban
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One of the major components in an automobile engine is the throttle valve part. It is used to keep up with emissions and fuel efficiency low. Design a control system to the throttle valve is newly common requirement trend in automotive technology. The non-smoothness nonlinearity in throttle valve model are due to the friction model and the nonlinear spring, the uncertainty in system parameters and non-satisfying the matching condition are the main obstacles when designing a throttle plate controller.
In this work, the theory of the Integral Sliding Mode Control (ISMC) is utilized to design a robust controller for the Electronic Throttle Valve (ETV) system. From the first in
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