Bilgi toplumu teknolojileri için anten sistemleri ve algılayıcılar

TÜBİTAK EEEAG01.10.2010Bu proje kapsamında, özellikle milimetre-dalga frekanslarında çalışan yeniden şekillendirilebilir anten, elektronik taramalı dizi anten ve yansıtıcı dizi anten tasarımı, üretimi ve ölçümleri yapılmıştır. Yeniden şekillendirilebilirlik özelliği için farklı teknolojiler kullanılmıştır. Huzmesi yönlendirilebilen sur biçimli mikroşerit yürüyen dalga anten dizisi X-bant uygulamalarında kullanılmak üzere tasarlamış, üretilmiş ve ölçülmüştür. Antenin ana huzmesinin istenilen yöne elektronik olarak döndürülebilmesini sağlayabilmek için mikroşerit hat üzerinde gerekli faz değişimini sağlayacak varaktör diyotlar kullanılmıştır. Yapılan EM benzetim ve ölçümler sonucu sur biçimli anten dizisinde, ana huzmenin diyot kontrolü ile tasarlandığı gibi 10 lik bir açı taraması yapabildiği gösterilmiştir. Bu kavram kanıtlaması şeklinde bir çalışmadır; huzmenin daha büyük açı aralığında tarama yapması için tasarımda yapılması gereken değişiklikler belirtilmiştir. MM-Dalga sabit genişlikli ve doğrusal sönümlenen yarık antenler tasarlanıp, üretilmiş ve antenin şeklinin, optik uyarımla bu iki yapı arasında değiştirilmesinin sağlanması durumunda ışıma örüntüsünün değiştirilebileceği gösterilmiştir. Proje kapsamında gerçekleştirilen bir diğer çalışmada da K ve Ka bantlarında bağımsız çalışabilen, RF MEMS anahtarlarla huzmesi elektronik olarak döndürülebilen dairesel polarizasyonlu yansıtıcı dizi anten tasarlanmış, üretilmiş ve ölçülmüştür. Çift frekanslı (24.4 GHz ve 35.5 GHz) dizi iç içe geçmiş farklı boyutlarda iki ayrık-halka dizisi şeklinde tasarlanmıştır. Huzme döndürme amacıyla her bir ayrık halkanın açısal konumunu RF MEMS anahtarlarla ayarlayarak, dairesel polarizasyonlu dalgaların fazları kontrol edilmektedir. Anten ODTÜ MEMS merkezinde geliştirilen yüzey mikro-işleme süreciyle üretilmiştir. Işıma örüntüleri ölçülmüş ve benzetim sonuçlarıyla karşılaştırılmıştır. Ölçümlerle, ana huzmenin, tasarlandığı gibi, Ka bandında 35°‟ye, K bandında 24°‟ye döndürülebildiği gösterilmiştir. Proje çalışmalarından sur biçimli mikroşerit anten dizisiyle ilgili hazırlanan makale Microwave and Optical Technology Letters adlı dergide yayınlanmak üzere kabul edilmiştir. Yansıtıcı dizi antenle ilgili makale de hazırlık sürecindedir. Saygın konferanslarda yedi bildiri sunulmuştur. Ayrıca, proje kapsamında üç yüksek lisans tez çalışması tamamlanmıştır.In this project, reconfigurable antenna, beam steering array and reflectarray have been designed, produced and measured, especially in mm-wave frequencies. To provide reconfigurability, different technologies have been considered. X-band electronically scanning meanderline microstrip traveling wave antenna array has been designed, produced and measured. To rotate the antenna beam to the desired direction, microstrip meander line has been loaded by varactor diodes that provide required phase shift values. EM simulations and rdiation pattern measurements of the meanderline antenna have demonstrated that the antenna has the capability to scan 10 with the control of varactors as designed. This is a proof-of-concept type study; alternative configurations to increase the scan range have also been discussed. MM-wave tapered slot antennas with a constant width and linear taper have been designed, produced and measured. It has been demonstrated that if the shape of the tapered slot antenna can be changed between constant width and linear taper structures by means of optical excitation, radiation pattern reconfigurability can be obtained. In another study accomplished in this project, electronically scanning circularly polarized reflectarray working independently in K and Ka bands has been designed, produced and measured. Dual band (24.4 GHz and 35.5 GHz) reflectarray has been designed as an interlaced array of split rings of two different sizes. In order to steer the beam, the phase of the incident circularly polarized wave is controlled by RF MEMS switches that modify the angular orientation of split-rings individually. The antenna has fabricated by using surface micromachining process developed in METU MEMS Center. Radiation patterns of the antenna are measured and compared with the simulations. It has been shown that the reflectarray is capable of beam switching to 35° in Ka band, 24° in K band as required. One journal paper on meanderline antenna has been accepted to be published in Microwave and Optical Technology Letters. Preparation of manuscript on reflectarray is under progress. Seven conference papers have been presented in well known Conferences. Furthermore, three Master Thesis studies have been accomplished during the project

The effect of supply chain management on business peformance: A study on hotel business

YÖK Tez No: 279984Turizm sektörü, son dönemlerde yaşanan ekonomik, sosyal, siyasal gelişmeler nedeniyle rekabetin en fazla yaşandığı sektörlerden birisidir. İşletmeler artık bireysel becerileriyle artan bu rekabet ortamında ayakta durmakta zorlanmaktadırlar. Bu ortamdaki rekabet şartları, firmaları birleşme ve yardımlaşma konularına daha fazla önem vermek zorunda bırakmıştır.Tedarik zinciri kavramı bu gelişmeler sonucunda ortaya çıkan bir kavramdır. Tedarik zinciri yönetimi, değişen bu rekabetçi çevrede firmaların başarısını etkileyen önemli uygulamalardan birisi olarak tartışılmaktadır.Bu çalışmanın amacı, turizm sektöründe faaliyet gösteren otel işletmelerinde tedarik zinciri yönetiminin boyutlarını belirlemek ve bu boyutların otel işletmelerinin performansı üzerindeki etkilerini araştırmaktır. Bu amaçları gerçekleştirmek için İstanbul'da faaliyetlerini sürdüren üç, dört ve beş yıldızlı oteller araştırmanın evreni olarak belirlenmiştir. Araştırma örneklemi kota örnekleme yöntemi ile seçilmiştir. Araştırmada nicel araştırma yöntemi kullanılmış, veriler anket tekniği kullanılarak elde edilmiştir. Elde edilen veriler SPSS 15,0 programı aracılığı ile analiz edilmiştir.Araştırma sonuçlarına göre otel işletmelerinde tedarik zinciri yönetiminin altı boyutlu bir olgu olarak anlaşıldığı belirlenmiştir. Bu boyutlar; yenilikçilik boyutu, rekabetçilik boyutu, kurumsal gelişime katkı boyutu, ilişki gücü boyutu, hız ve esneklik boyutu ve müşteri ilişkiler boyutu şeklindedir. Otel işletmelerinde performans yönetimi kavramı ise beş boyutlu bir olgu olarak algılanmaktadır. Bu boyutlar: finansal performans, yenilikçilik performansı, kurum içi gelişim performansı, çalışan performansı ve müşteri performansı şeklindedir.Araştırma sonuçlarına göre tedarik zinciri yönetimi boyutlarından yenilikçilik boyutu, rekabetçilik boyutu, kurumsal gelişime katkı boyutu, ilişki gücü boyutu ve müşteri ilişkiler boyutunun işletme performansını pozitif olarak etkilemediği görülmektedir. Tedarik zinciri yönetimi boyutlarından hız ve esneklik boyutu ise otel işletmelerinin performansını pozitif olarak etkilemektedir.Tourism industry is one of the most competitive sectors, because of the social, economical and political developments experienced nowadays.These competitive conditions forced firms to consider more important working together and acting with solidarity.Supply chain is a concept that comes into being as a result of these develops. Supply chain management is discussed as one of the important applications that affect the successes of firm in the competitive milieu.The aim of this study is to determine dimensions of supply chain management on hotels that performing in tourism sector and to search the effects of these dimensions on hotel performance. To become true these aims, it has been decided as research population 3, 4 and 5 stared hotels that performs in Istanbul. Research sampling has been chosen with quota sampling method. It has been used quantitative research method, the data have been obtained with survey technique. The obtained data have been analyzed by SPSS 15, 0 program.According to research results it has been determined that supply chain management at hotel businesses has six dimensions. The dimensions are innovation dimension, competitiveness dimension, supplement to association development dimension, relationship power dimension, speed and flexibility dimension and customer relationship dimension. However, performance management concept has been perceived at hotel businesses as five dimensioned phenomenon. These dimensions are financial performance, innovation performance, performance of business-internal development, employee performance and customer performance.According to research results; it is seemed that the dimensions of supply chain management innovation dimension, competitiveness dimension, supplement to association development dimension, relationship power dimension and customer dimension haven?t affected positively to the business performance. The dimension of supply chain management, speed and flexibility dimension, however, has affected positively the performance of hotel business

Çift frekansta çalışan yeniden yapılandırılabilir RF MEMS anahtarlı ayrık halka yansıtıcı dizi anteni.

Dual band (K and Ka) electronically scanning reflectarray with RF MEMS switches is designed, implemented and measured. Unit cell of the reflect array is composed of conductor backed split-ring elements. In order to steer the beam, the phase of the incident circularly polarized wave is controlled by RF MEMS switches that modify the angular orientation of split-rings individually. Reflectarray is designed using unit cell approach with periodic boundary conditions. The antenna is fabricated by using surface micromachining process developed in METU MEMS Center. Radiation patterns of the antenna are measured and compared with the simulations. It has been shown that the reflectarray is capable of beam switching to 35° in Ka band, 24° in K band.M.S. - Master of Scienc

Local food availability in menus of hotels: The case of Batman, Turkey

The purpose of this study is to find out the availability of the local dishes of the city of Batman in the menus of the accommodation establishments. Therefore, at first, the local dishes of this city were compiled via document analysis technique. As a result of this compilation, for the study, semi-structured interviews were conducted with the managers or head chefs of 13 accommodation establishments located in Batman. As a result of these interviews, it was revealed that none of the accommodation establishments include local dishes in their menus. Furthermore, other results presented that the visitors have a demand towards local dishes and that they prefer local dishes when it is offered as an alternative. Within the context of local dishes, it was exhibited that the local tandoor bread was served to the visitors only in three hotels operating in a bed and breakfast system and this bread has been in demand

Local food availability in menus of hotels: The case of Batman, Turkey

The purpose of this study is to find out the availability of the local dishes of the city of Batman in the menus of the accommodation establishments. Therefore, at first, the local dishes of this city were compiled via document analysis technique. As a result of this compilation, for the study, semi-structured interviews were conducted with the managers or head chefs of 13 accommodation establishments located in Batman. As a result of these interviews, it was revealed that none of the accommodation establishments include local dishes in their menus. Furthermore, other results presented that the visitors have a demand towards local dishes and that they prefer local dishes when it is offered as an alternative. Within the context of local dishes, it was exhibited that the local tandoor bread was served to the visitors only in three hotels operating in a bed and breakfast system and this bread has been in demand

The Effects of Islamic Work Ethics and the Ethics of Love of Money over the Perception of Smuggling: The Example of the Alanya Tradesmen

WOS: 000439232500001This study intends to identify the thoughts of tradesmen active in commerce directed towards smuggling, which constitutes a crime in accordance with the Anti-Smuggling Act No. 5607 and was passed on March 21, 2007, as well as to reveal the relationship between their perception of the variables of Islamic work ethics and love of money. In this context, the provincial center in Alanya was identified as an important tourist destination in the universe of the research, as well as having an intensity of trade operations. Because the whole of the research universe could not be reached, 384 samples were determined to be necessary for them to go and arrive at the path of specification. Easy sampling was preferred; 510 questionnaires were distributed as a quantitative data collection technique, and 498 usable questionnaires were investigated in the context of the research. According to the research results, the participants had high levels of perceptions related to the smuggling of many commercial products. However, the participants had perceptions in the direction that smuggling was done by those who came to Alanya to work, especially from outside; smuggling took place overland; and smuggling is done because of the economic benefits it provides and the fines are not a deterrent. When looking at the relationship between the variables, the perception of Islamic work ethics affected the change in perception towards smuggling being a bad behavior. Additionally, the dimensions of love of money (good and budget) were determined as variables that also significantly explained changes in the perception of smuggling