MF - Makale Koleksiyonu | İnşaat Mühendisliği Bölümü / Civil Engineeringİnşaat Mühendisliği Bölümüne ait makale koleksiyonunu içerir.https://hdl.handle.net/11729/7642024-03-28T12:42:02Z2024-03-28T12:42:02ZA novel nonlinear frequency modulated chirp signal for synthetic aperture radar and sonar imagingBayındır, Cihanhttps://hdl.handle.net/11729/53102023-01-31T11:33:05Z2016-01-20T00:00:00ZA novel nonlinear frequency modulated chirp signal for synthetic aperture radar and sonar imaging
Bayındır, Cihan
In order to maintain average power levels as well as high range resolution, phasecoded signals are used in radar and sonar signal processing. One of the most commonly used phase-coded signals is the linear frequency modulated chirp waveform. Various nonlinear frequency-modulated chirps are offered as alternatives to linear frequency modulated chirp. In this paper a new nonlinear frequency modulated chirp waveform is proposed. Properties like bandwidths, point spread functions and Fourier transforms are given for the proposed chirp signal. Synthetic imagery for spotlight imaging geometry is reconstructed by using the polar format and Stolt format processing techniques using the linear frequency-modulated (LFM) and proposed nonlinear frequency modulated chirp. Comparisons are presented, and it is shown that proposed waveform can improve the sonar image resolution.; Radar ve sonar sinyal işlemede ortalama güç seviyeleriyle birlikte yüksek çözünürlüğü sağlayabilmek için evre-kodlu sinyaller kullanılmaktadır. En sıkça kullanılan sinyallarden biri de lineer sıklık değişimli (linear frequency modulated-LFM) sinyaldir. Lineer sıklık değişimli sinyale alternatif olarak bazı lineer olmayan sıklık değişimli sinyaller de ortaya atılmıştır. Bu çalışmada yeni bir lineer olmayan sıklık değişimli sinyal önerilmiştir. Ortaya atılan sinyalin; bant aralığı, nokta dağılım fonksiyonu ve Fourier dönüşümü gibi özellikleri sunulmuştur. Lineer sıklık değişimli sinyal ve önerilen lineer olmayan sıklık değişimli sinyal kullanılarak kutupsal format ve Stolt format işleme teknikleriyle sentetik görüntüler oluşturulmuş ve ortaya atılan sinyalin sonar görüntü çözünürlüğünü geliştirdiği gösterilmiştir.
2016-01-20T00:00:00ZDetermining pull-out deformations by means of an online photogrammetry monitoring systemAvşar, Emin ÖzgürAltan, Mehmet OrhanDoğan, Ünal AnılAkça, Devrimhttps://hdl.handle.net/11729/52642023-01-20T03:57:14Z2015-03-02T00:00:00ZDetermining pull-out deformations by means of an online photogrammetry monitoring system
Avşar, Emin Özgür; Altan, Mehmet Orhan; Doğan, Ünal Anıl; Akça, Devrim
Chemical anchorages are applied in many engineering implementations, particularly strengthening of reinforced concrete structures. During strengthening procedure; chemical anchorages should be tested, since they supply to transfer the load between existing construction elements and newly added elements. Therefore; the study of the quality of chemical anchorages is an important issue in construction materials science. In this context; the most important experiment is to determine the pull-out loads of embedded anchorage reinforcement by applying axial loads. In this study; it is aimed to determine the displacements of steel reinforcements, embedded into concrete by using chemical anchorages, while applying axial pulling loads. In order to determine the displacements and load - deformation graphs; starting conditions and every 10 bar pressure applied conditions of the steel reinforcements were captured by the cameras. The obtained images were evaluated by using photogrammetric software. Based on the photogrammetric post-processing results, the load - deformation graphs were plotted and the loads at loss of adhesion were determined.
2015-03-02T00:00:00ZAnalysis of the benefits, challenges and risks for the integrated use of BIM, RFID and WSN: a mixed method researchSeyis, SenemSönmez, Alperen Merthttps://hdl.handle.net/11729/43542023-11-10T19:08:11Z2023-07-11T00:00:00ZAnalysis of the benefits, challenges and risks for the integrated use of BIM, RFID and WSN: a mixed method research
Seyis, Senem; Sönmez, Alperen Mert
Purpose The purpose of this study is to identify, classify and prioritize the benefits, challenges and risks for the integrated use of building information modeling (BIM), radio frequency identification (RFID) and wireless sensor network (WSN) in the architecture, engineering, construction and operation (AECO) industry. Design/methodology/approach This study relies on the mixed method approach which consists of systematic literature review, semistructured interviews and Delphi technique. A systematic literature review was performed and face-to-face semistructured interviews with seven subject matter experts (SMEs) were conducted for identification and classification purposes. Delphi method was applied in two structured rounds with eleven SMEs for prioritization purpose. These three research techniques were chosen to reach the most accurate data by combining different perspectives on the subject matter. Data gathered by these three methods was triangulated to increase the validity and reliability of this research. Findings Thirteen benefits, ten challenges and four risks for the integrated use of BIM, RFID and WSN were identified. The results could aid the practitioners and researchers comprehend the pros and cons of this integration by representing SMEs' valuable insights and perspectives about the current and future status, trends, limitations and requirements of the AECO industry. The identified risks and challenges show the requirements for future studies while the benefits demonstrate the capabilities and the potential contributions of this hybrid integration to the AECO industry. Originality/value The integration of BIM, RFID and WSN is still not commonly implemented in the AECO industry. Some studies focused on this topic; however, none of them reveals the benefits, risks and challenges for integrating BIM, RFID and WSN in a holistic manner. This research makes a significant contribution to the AECO literature and industry by uncovering the benefits, challenges and risks for the integrated use of BIM, RFID and WSN that could increase industry applications.
2023-07-11T00:00:00ZInvestigation of the relationship between upstream and on-ramp flows at downstream capacity level on Istanbul freeway mergesAksoy, GökerÖğüt, Kemal Selçukhttps://hdl.handle.net/11729/32992022-09-23T12:36:36Z2021-03-04T00:00:00ZInvestigation of the relationship between upstream and on-ramp flows at downstream capacity level on Istanbul freeway merges
Aksoy, Göker; Öğüt, Kemal Selçuk
Traffic congestion usually occurs at freeway merges due to the inequality of lane numbers at upstream and downstream. The freeway entry, defined as on-ramp, is the main cause of this irregularity and in order to clarify its effect, three freeway merges are investigated in this study with macroscopic flow parameters where a variety of geometric properties are present. In each merge, when the capacity flow is achieved at downstream, the on-ramp and upstream flows are determined and the relationship between upstream flow rate and ‘on-ramp ratio’, which is calculated by dividing the on ramp flow rate to the sum of on-ramp and upstream flow rates, is investigated. An inverse relationship is determined between total upstream flows (upstream flow plus on-ramp flow) with respect to on-ramp ratio. As a result, the merge with one lane drop and three-lanes at downstream seems to be least influenced type while the merge with two lanes drop and four lanes at downstream is the highest. For the former, 1% increase in on-ramp ratio causes a reduction of 20 pcu/h/lane on sum of total upstream flows while for the latter 26 pcu/h/lane. It is seen that the term on ramp ratio, can be quite useful variable for establishing capacities of freeway merges with the help of upstream and on-ramp traffic demands.; Otoyollarda yaşanan trafik sıkışıklıkları genellikle katılım bölgelerinde akım yukarı ve akım aşağı yöndeki şerit sayılarının eşitsizliğinden kaynaklanmaktadır. Bu çalışmada, şerit sayıları açısından değişiklik gösteren üç farklı katılım bölgesinde tıkanıklığa neden olan akım değerleri makroskopik akım değişkenleri kullanılarak incelenmiştir. Her katılımda, akım aşağı yön kapasiteye ulaştığında, anayol üzerindeki akım aşağı ve akım yukarı yöndeki hacimler ile katılım hacimleri belirlenmiştir. Bu an için belirlenen katılım hacmi, katılan hacmi ve akım yukarı yöndeki hacmin toplamına bölünerek “katılım oranı” terimi hesaplanmıştır. Toplam akım yukarı hacim (akım yukarı hacim ve katılım hacmi toplamı) ile katılım oranı arasında ters orantılı bir etkileşim bulunmuştur. Sonuç olarak, bu etkileşimin akım aşağı yönde üç şeridi bulunan ve bir şerit azalmasının görüldüğü otoyol katılım bölgesi birleşiminde en az olduğu, akım aşağı yönde dört şeridi bulunan ve iki şerit azalan otoyol katılım bölgesinde ise en fazla olduğu belirlenmiştir. Katılım oranında %1’lik artış, sözü edilen ilk katılım bölgesinde toplam akım yukarı hacmini 20 bo/sa/şrt azaltırken, ikinci katılım bölgesinde 26 bo/sa/şrt azalmaya neden olmaktadır. Katılım oranı teriminin, otoyol katılım bölgelerinde kapasitelerinin belirlenmesinde ve kapasite akımını oluşturan katılım hacmi ile akım yukarı hacminin ilişkilendirilmesinde yararlı bir araç olabileceği görülmektedir.
2021-03-04T00:00:00Z