نتایج جستجو برای: communication systems

تعداد نتایج: 1451634  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس 1389
هدیه الیاسی, عبدالرضا نبوی,

growing demands and requires of high data rate systems cause significant increase of high frequency systems for wideband communication applications. as mixers are one of the main blocks of each receivers and its performance has great impact on receiver’s performance; in this thesis, a new solution for ku-band (12-18 ghz) mixer design in tsmc 0.18 µm is presented. this mixer has high linearity a...

15 صفحه اول
پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه بیرجند 1388
حسین رحمانی دارنجانی, ناصر ندا, ناصر مهرشاد,

a significant problem in multicarrier communication systems is the necessity to reduce the value of papr (peak-to-average power ratio) of transmitting signal. in this thesis we study the effect of the system parameters such as coding and modulation types on papr and ultimate ber in a mc-cdma system. in this study we consider fading channel as well as the nonlinearity of transmitter’s amplifier ...

15 صفحه اول
پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تحصیلات تکمیلی صنعتی کرمان - پژوهشکده برق و کامپیوتر 1390
کیوان کیارش, محسن صانعی, احمد حکیمی,

a phase-locked loop (pll) based frequency synthesizer is an important circuit that is used in many applications, especially in communication systems such as ethernet receivers, disk drive read/write channels, digital mobile receivers, high-speed memory interfaces, system clock recovery and wireless communication system. other than requiring good signal purity such as low phase noise and low spu...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس 1389
محمد امیر ثابت حاجیونی, عباس آسوشه,

abstract: country’s fiber optic network, as one of the most important communication infrastructures, is of high importance; therefore, ensuring security of the network and its data is essential. no remarkable research has been done on assessing security of the country’s fiber optic network. besides, according to an official statistics released by ertebatat zirsakht company, unwanted disconnec...

15 صفحه اول
Journal: :مدیریت اطلاعات سلامت 0
سیدحسام سیدین استادیار، مدیریت خدمات بهداشتی درمانی، دانشگاه علوم پزشکی تهران، تهران، ایران. حانیه سادات سجادی دانشجوی دکتری تخصصی، مدیریت خدمات بهداشتی درمانی، دانشگاه علوم پزشکی تهران، تهران، ایران و کارشناس ارشد، مدیریت خدمات بهداشتی درمانی، دانشگاه علوم پزشکی اصفهان، اصفهان، ایران روح اله زابلی دانشجوی دکتری تخصصی، مدیریت خدمات بهداشتی درمانی، دانشگاه علوم پزشکی تهران، تهران، ایران و مربی، مدیریت خدمات بهداشتی درمانی، دانشگاه علوم پزشکی بقیه اله، تهران، ایران

background: accurate and timely information and communication are vital to adequately prepare individual health organizations for emergency events. the current article investigated health-related communication and information systems for emergency management in iran. methods: the present study was conducted in 2009 with a mixed qualitative and quantitative approach. simple random purposeful sam...

متن کامل
پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - دانشکده علوم اجتماعی و اقتصادی 1389
احمد مداحی, علی محقر,

abstract nowadays, the science of decision making has been paid to more attention due to the complexity of the problems of suppliers selection. as known, one of the efficient tools in economic and human resources development is the extension of communication networks in developing countries. so, the proper selection of suppliers of tc equipments is of concern very much. in this study, a ...

15 صفحه اول
Journal: :advances in railway engineering 0
anil ates istanbul transportation cooperation hakan celik istanbul transportation telecommunication and security tech.

after 1860’s the railway systems has started to be used in urban transportation in the world. however, especially after the 1950’s, automobile usage has been increased quickly. thus the dense of transportation has started to move from railway systems to the ones with rubber tire vehicles in istanbul. traffic density in urban transportation has started to be experienced since 1950 with the incre...

متن کامل
Journal: :amirkabir international journal of modeling, identification, simulation & control 2015
akram beigi nasser mozayani

agents, in a multi agent system, communicate with each other through the process of exchanging messages which is called dialogue. multi agent organization is generally used to optimize agents’ communications. holonic organization demonstrates a self-similar recursive and hierarchical structure in which each holon may include some other holons. in a holonic system, lateral communication occurs b...

متن کامل
Journal: Journal of Communication Engineering 2016
A. Bagheri, GH. Abed Hodtani

In this paper, we analyze the secure connectivity in Shotgun cellular systems (SCS: Wireless communication systems with randomly placed base stations) by Poisson intrinsically secure communication graph (IS-graph), i.e., a random graph which describes the connections that are secure over a network. For a base-station in SCS, a degree of secure connections is determined over two channel models: ...

متن کامل
Journal: :trauma monthly 0
reza alizadeh trauma research center, baqiyatallah university of medical sciences. postal code19945/581. mollasadra st, ir iran +98-2188053776, dr_sagafi@yahoo.com; department of ophthalmology, khatam-al-anbia eye hospital , faculty of medicine, mashhad university of medical sciences, ir iran farzad panahi trauma research center, baqiyatallah university of medical sciences. postal code19945/581. mollasadra st, ir iran +98-2188053776, dr_sagafi@yahoo.com masoud saghafinia trauma research center, baqiyatallah university of medical sciences. postal code19945/581. mollasadra st, ir iran +98-2188053776, dr_sagafi@yahoo.com; trauma research center, baqiyatallah university of medical sciences. postal code19945/581. mollasadra st, ir iran +98-2188053776, dr_sagafi@yahoo.com keivan alizadeh trauma research center, baqiyatallah university of medical sciences. postal code19945/581. mollasadra st, ir iran +98-2188053776, dr_sagafi@yahoo.com; department of interventional cardiology, rajaee heart hospital, tehran university of medical sciences, ir iran neusha barakati faculty of medicine, mashhad university of medical sciences, ir iran mohammad khaje-daloee department of epidemiology and statistics, faculty of medicine, mashhad university of medical sciences, ir iran

background trauma still stands atop of the list of emergencies. transfer of these patients via emergency medical services (ems) dispatch is critical with regard to importance of timing. this aspect has achieved greater importance due to population increase and telephone triage. objectives we aimed to decrease unnecessary emergency medical services (ems) missions via a computer program designed ...

متن کامل

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید

function paginate(evt) { url=/search_year_filter/ var term=document.getElementById("search_meta_data").dataset.term pg=parseInt(evt.target.text) var data={ "year":filter_year, "term":term, "pgn":pg } filtered_res=post_and_fetch(data,url) window.scrollTo(0,0); } function update_search_meta(search_meta) { meta_place=document.getElementById("search_meta_data") term=search_meta.term active_pgn=search_meta.pgn num_res=search_meta.num_res num_pages=search_meta.num_pages year=search_meta.year meta_place.dataset.term=term meta_place.dataset.page=active_pgn meta_place.dataset.num_res=num_res meta_place.dataset.num_pages=num_pages meta_place.dataset.year=year document.getElementById("num_result_place").innerHTML=num_res if (year !== "unfilter"){ document.getElementById("year_filter_label").style="display:inline;" document.getElementById("year_filter_place").innerHTML=year }else { document.getElementById("year_filter_label").style="display:none;" document.getElementById("year_filter_place").innerHTML="" } } function update_pagination() { search_meta_place=document.getElementById('search_meta_data') num_pages=search_meta_place.dataset.num_pages; active_pgn=parseInt(search_meta_place.dataset.page); document.getElementById("pgn-ul").innerHTML=""; pgn_html=""; for (i = 1; i <= num_pages; i++){ if (i===active_pgn){ actv="active" }else {actv=""} pgn_li="
  • " +i+ "
    • "; pgn_html+=pgn_li; } document.getElementById("pgn-ul").innerHTML=pgn_html var pgn_links = document.querySelectorAll('.mypgn'); pgn_links.forEach(function(pgn_link) { pgn_link.addEventListener('click', paginate) }) } function post_and_fetch(data,url) { showLoading() xhr = new XMLHttpRequest(); xhr.open('POST', url, true); xhr.setRequestHeader('Content-Type', 'application/json; charset=UTF-8'); xhr.onreadystatechange = function() { if (xhr.readyState === 4 && xhr.status === 200) { var resp = xhr.responseText; resp_json=JSON.parse(resp) resp_place = document.getElementById("search_result_div") resp_place.innerHTML = resp_json['results'] search_meta = resp_json['meta'] update_search_meta(search_meta) update_pagination() hideLoading() } }; xhr.send(JSON.stringify(data)); } function unfilter() { url=/search_year_filter/ var term=document.getElementById("search_meta_data").dataset.term var data={ "year":"unfilter", "term":term, "pgn":1 } filtered_res=post_and_fetch(data,url) } function deactivate_all_bars(){ var yrchart = document.querySelectorAll('.ct-bar'); yrchart.forEach(function(bar) { bar.dataset.active = false bar.style = "stroke:#71a3c5;" }) } year_chart.on("created", function() { var yrchart = document.querySelectorAll('.ct-bar'); yrchart.forEach(function(check) { check.addEventListener('click', checkIndex); }) }); function checkIndex(event) { var yrchart = document.querySelectorAll('.ct-bar'); var year_bar = event.target if (year_bar.dataset.active == "true") { unfilter_res = unfilter() year_bar.dataset.active = false year_bar.style = "stroke:#1d2b3699;" } else { deactivate_all_bars() year_bar.dataset.active = true year_bar.style = "stroke:#e56f6f;" filter_year = chart_data['labels'][Array.from(yrchart).indexOf(year_bar)] url=/search_year_filter/ var term=document.getElementById("search_meta_data").dataset.term var data={ "year":filter_year, "term":term, "pgn":1 } filtered_res=post_and_fetch(data,url) } } function showLoading() { document.getElementById("loading").style.display = "block"; setTimeout(hideLoading, 10000); // 10 seconds } function hideLoading() { document.getElementById("loading").style.display = "none"; } -->