itüdergisi (E-Journals - İstanbul Teknik Üniversitesi, Istanbul Teknik Uniersity., İTÜ)
itüdergisi (E-Journals - İstanbul Teknik Üniversitesi, Istanbul Teknik Uniersity., İTÜ)Not a member yet
1059 research outputs found
Sort by
Kentsel koruma sürecinde görselleştirme tekniklerinin etkinliğinin değerlendirilmesi
Get PDFInvestigation of visualization technique's efficiency is important with the reliability and accuracy of the technique regarding representation level of the spatial content in the process of urban historic site evaluation. When comparing to traditional visualization techniques, computer aided three-dimensional urban models have more capability to attain communication and interaction among various user groups. As innovative visualization techniques, three-dimensional urban models visualize spatial information comprehensively. But, these models are occasionally used to represent the final view of the urban structure and expressions of planning and design proposals. Comprehensive spatial analyses and investigations are required in urban planning and conservation studies devoted to evaluation of urban historic sites by the utilization of visualization techniques. Efficiency levels of various visualization techniques may vary in the different stages of urban conservation process, then examination of negative and positive aspects of these techniques have been anticipated to provide contributions directly to spatial analyses and investigations in urban historic sites. This study, examine the efficiency of three-dimensional urban models which is developed with the functional attributes and sufficient accuracy level in comprehensive spatial content while improving the communication and interaction between different user groups. This examination is held within the comparison of efficiency levels between three-dimensional urban model and two-dimensional mapping technique. The aim of this study is to develop three-dimensional urban model as an efficient and innovative visualization technique in order to evaluate urban historic site. Methodology in the research model is based on the questionnaire which is gathering the graduate students' responses regarding the efficiency of two and three-dimensional visualization techniques in urban conservation process. Then responds are investigated and assessed in quantitative methods with descriptive statistics in order to measure how efficiently the spatial content or information is perceived and comprehended by means of both visualization techniques and to compare the efficiency levels of these techniques. As the fundamental finding of the study, it is concluded that more functional attributes in three-dimensional urban models are defined in the comprehensive spatial analyses and investigations in the contrary with two-dimensional mapping technique. When comparing the efficiency levels of both visualization techniques, three-dimensional urban model has higher scores in more variables but the most prominently in comprehension of topography, orientation sense of users and cognition of the project. As visualization techniques affect the users? perception and spatial evaluation in urban historic site, three-dimensional urban model is more capable of representing the harmony parameters related to urban structure, visual characteristics and accessibility. In regard to the opportunities for utilization of three-dimensional urban models, this study demonstrates the appropriateness with which key components in the urban conservation process-topographical studies, analyses of building height and harmony are more efficiently represented with three-dimensional visualization techniques. On the contrary, two-dimensional mapping technique expresses less parameter in urban structure. Only proposed building size and proportion is efficiently defined in conventional mapping technique. Although conventional mapping technique has less capable of expressing the characteristics of urban historic site, combination of two and three-dimensional visualization technique is best to define and express the spatial content and information in urban historic sites. In conclusion, as accurate and reliable visualization techniques three-dimensional urban models, define more attributes in spatial content, improve the user's perception regarding the characteristics related to harmony in urban historic site and finally enhance the communication and interaction among graduate students defined as professional group in order to develop urban conservation applications in collaborative planning approach. Keywords: Urban conservation, visualization techniques, three dimensional urban model, CAD.Kentsel koruma sürecinde üç boyutlu görselleştirme ve sunum teknikleri, mekansal bilgi sistemlerindeki gelişime paralel olarak anıtsal ve sivil mimarlık eserlerinin belgelenmesi ve tarihi çevrelerin değerlendirilmesinde sağladığı teknolojik olanaklarla önem kazanmaktadır. Bu çalışmanın temel amacı, tarihi çevrenin değerlendirilmesinde etkin ve yenilikçi bir görselleştirme tekniği olarak üç boyutlu kentsel modelin geliştirilmesi ve meslek adamlarının algısına yönelik olarak bu modelin etkinliğinin değerlendirilmesidir. Bu değerlendirme kapsamında önerilen üç boyutlu kentsel model geleneksel görselleştirme ve sunum tekniği olarak iki boyutlu haritalama tekniğiyle karşılaştırılmaktadır. Bu çalışma, tarihi kentsel çevrenin değerlendirilmesi sürecinde, mekansal bilgi sistemlerinde güvenilirlik ve hassasiyet, kapsamlı mekansal içerikte işlevsellik ile bilgi erişimi ve paylaşımı fonksiyonlarını bütüncül biçimde kullanarak üç boyutlu kentsel model önerisini geliştirmeyi öngörmektedir. Uygulama alanı olarak seçilen Zeyrek tarihi kentsel alanında iki boyutlu haritalama tekniği ile hazırlanan görseller ve önerilen üç boyutlu kentsel model, lisansüstü öğrencilerine yapılan anket görüşmeleriyle değerlendirilmektedir. Çalışma, görselleştirme tekniklerinin etkinliğinin değerlendirilmesinde betimleyici ölçme yöntemi olarak gruplar arası ortalama farklarının ve anlamlılık düzeylerinin karşılaştırılması ve sınanması ile gerçekleştirilmektedir. Çalışmanın sonucunda, geleneksel iki boyutlu haritalama tekniklerine göre üç boyutlu kentsel modelin, tarihi kentsel alanın mekansal özelliklerini daha başarılı biçimde tanımlayabildiği görülmektedir. Meslek adamlarının algısına göre, üç boyutlu kentsel modelin en önemli özelliği, tarihi kentsel alanın mekansal içeriğini tanımlama, algılama ve kavrama düzeylerini geliştirmesidir. Anahtar Kelimeler: Kentsel koruma, görselleştirme teknikleri, üç boyutlu kentsel model, Computer Aided Design (CAD)
İstanbul'da şehirsel saçaklanmanın ölçülmesi
Get PDFSprawling urban development is one of the major concerns in terms of sustainable urban development. Critics of sprawl argue that urban expansion invade the agricultural land, leading to a loss of amenity benefits from open space. In addition, growth at the urban fringe is thought to depress the incentive for redevelopment of land closer to city centers, leading to decay of city centers. Under free-market conditions the decisions of individuals minimize costs and maximize profit. This is mostly in favour of conversion of rural land leading to sprawling urban development because it is easier and more profitable due to lower land values. In response to concerns about sprawl, compact development strategies have been proposed in order to alleviate the market failures and promote sustainable development. Therefore, urban planners require information related to the rate of growth, pattern and extent of sprawl to provide basic measurements to define sprawl characteristics. Measuring urban sprawl is a controversial topic among scholars who investigate the urban landscape. There have been many attempts to measure sprawl by developing quantifiable indicators. Density is considered as one of the essential components of measuring sprawl. Since density is a very complex concept and its measures vary in several ways, it is important to determine how the relationship between density and sprawl should be evaluated. The density gradient is an alternative approach to quantifying density instead of using the number of people or dwelling units per given area. The idea of a density gradient is the percentage change in density for a small change in distance from an urban center, or the density gradient of sprawl. It can be argued that the density gradient model, which generalizes urban form as monocentric, is a good fit in explaining urban dynamism as cities grow and economies develop. Using measurable indicators, researchers created a sprawl index based on factors that can be analyzed. Recently, scholars have also identified measurable characteristics of sprawl and proposed specific indicators of sprawl to characterize patterns of urban growth and land use. The other attempts involve using certain spatial simulation techniques to measure urban form both in theoretical simulations and while using empirical data. The aim of this paper is to provide a sprawl measurement methodology that contributes to the understanding of sprawl dynamics of Istanbul. In this paper, a sprawl index was calculated to measure urban sprawl in Istanbul. The information that was used in the sprawl index was assembled for each of 787 neighborhoods of Istanbul. For each neighborhood level, the built up areas of neighborhoods have been taken as the statistical units for the calculation of the sprawl index. 18 variables related to built-up areas were collected and entered into database. Using factor analysis 18 indicators were explained by three components (density, mix-use and accessibility) and then each neighborhood received density score, mix-use score and accessibility score. Since "density" and "accessibility" have an inverse effect in the context of urban sprawl measurement, the accessibility factor is considered as a negative component, while density and mix-use were considered as positive component in the calculation of sprawl index. Consequently, using sprawl score, Istanbul is divided into five zones ranging from the most sprawled to the most compact. The results demonstrate that the spatial development pattern of Istanbul exhibits urban sprawl characteristics. Current planning approach alone is not effective to reduce sprawl without setting certain spatial strategies by which development activity is restricted or additional requirements for new development are imposed in certain areas. This brings the compact development strategies to planners' attention as a way to control urban sprawl. For further research, it should be investigated if uncontrolled urban sprawl might feasibly be shifted from the areas where it now seems likely to occur into other areas closer to the center of the metropolitan areas. Keywords: Urban spatial development, compact development, urban sprawl, sprawl index, Istanbul.Şehirsel saçaklanma sürdürülebilir gelişme karşısındaki en önemli sorunlardan biri olarak kabul edilmektedir. Saçaklanma, şehrin yayılarak tarım alanlarını ve çevreyi işgal etmesi, doğal açık alanların sağladığı pek çok yararları ortadan kaldırması, ulaşım maliyetlerini arttırması ve kent merkezlerinin köhneleşmesine neden olması gibi bir dizi problemlere neden olması açısından eleştirilmektedir. Serbest piyasa koşullarında bireyler ve girişimciler kararlarını, karlarını maksimum, zararlarını ise minimum yapacak şekilde vermektedirler. Bu durum ise çoğunlukla çeperlerdeki kırsal alanların, şehrin yeni gelişme alanlarına çevrilmesine neden olmaktadır. Çünkü çeperlerdeki boş arazilerin varlığı ve arazi değerlerinin düşük olması, bu bölgelerde konut alanı üretmeyi daha kolay, daha az riskli ve böylece karlı duruma getirmektedir. Bu nedenle şehirsel büyümenin, zaman içerisindeki eğilimlerinin tespit edilmesi, sürdürülebilirlik açısından değerlendirilerek problemlerinin belirlenmesi ve bu problemlerin çözümünün sistematik olarak ele alınması, geleceğe dönük şehirsel büyüme politikaları ve stratejilerinin belirlenmesi açısından oldukça önem taşımaktadır. Bu nedenle bu çalışmada, İstanbul’da yakın gelecekte daha sürdürülebilir gelişme koşullarının oluşturulması için şehirsel büyümenin, belirli mekânsal gelişme stratejileriyle değerlendirilmesine duyulan ihtiyaç ortaya konmuştur. Bu çalışma, İstanbul’daki konut alanlarının mekânsal büyüme karakteristiğini mekânsal analiz yöntemleri ile çözümlemeyi amaçlamaktadır. Çalışmada, faktör analiziye bir saçaklanma indeksi geliştirilmiştir. Daha sonra saçaklanma indeksi kullanılarak İstanbul’un bugün gelinen noktadaki kentsel alanın mekânsal karakteristiği şehirsel saçaklanma ve kompakt gelişme açısından değerlendirilmiştir. Çalışmanın sonunda, İstanbul’un şehirsel büyüme karakteristiğinin şehirsel saçaklanma özelliği gösterdiği ortaya konmuştur. Anahtar Kelimeler: Mekânsal büyüme, kompakt gelişme, şehirsel saçaklanma, saçaklanma indeksi, İstanbul
Developing models of pavement performance estimation using fuzzy logic and regression analyze approach for the motorway network in Turkey
Get PDFUlaştırma yatırımlarının devlet tarafından finanse edilmesi ve işletilmesi geleneği yakın zamanlara kadar sürmüştür. Ne var ki tüm dünyada ulaştırma yatırımlarına olan gereksinimin artışı ve kamu kesimi kaynaklarının sınırlılığı, devletlerin asli görevleri olarak görülen kamu hizmeti anlayışını değişime zorlamıştır. Bu bağlamda özel sektörün ilgisinin ulaştırma altyapı yatırımlarına çekilerek ihtiyaçların kamu kaynaklarına gerek kalmadan veya daha az kamu katkısıyla giderilmesi amaçlanmakta ve bunun yolları aranmaktadır. Günümüzde yeni otoyolların yapımı her geçen gün azalmakta, motorlu taşıt trafiğindeki sürekli artışlar ve kaynak sağlanmasındaki güçlükler karşısında, yeni otoyolu yapmaktan çok mevcut otoyol üstyapılarının, gelecekteki yoğun ve ağır trafiğe cevap verebilecek şekilde bakımı, onarımı ve yenilenmesi gibi çalışmalar daha çok önem kazanmaktadır. Türkiye otoyol ağının bakım ve onarımı için çok yüksek değerlere ulaşan bütçe gereksinimleri nedeniyle, sınırlı kaynaklara sahip bulunan ülkemizde, kaynakların daha verimli biçimde kullanılmasını sağlamak amacıyla, otoyol ağı içindeki yollarda, Üstyapı Yönetim Sistemi’nin uygulanması zorunlu hale gelmiş bulunmaktadır. Üstyapı Yönetim Sistemi (ÜYS), sınırlı mevcut bir bütçeye, en yüksek kazanç sağlayacak optimum bakım/iyileştirme önceliği programlarını oluşturmak için, nesnel ve sistematik yaklaşım taşımaktadır. Bu çalışmada; Karayolları Genel Müdürlüğü’nce yapılan ölçümlerin (IRI, RN) sonucunda toplanan veriler kullanılarak, otoyolların üstyapısında bozulmaların ne zaman meydana geleceğinin, oluşturulacak modeller (fuzzy logic, regresyon analizi) yardımıyla saptanması hususunda, ülkemiz koşullarına uygun örnek bir Üstyapı Yönetim Sistemi (ÜYS)’nin kurulması amaçlanmaktadır. Anahtar Kelimeler: Üstyapı Yönetim Sistemi, bulanık mantık, IRI, RN.21. Century World of transportation services without adequate and contemporary social and economic life is not possible to keep alive and dynamic. The main aim of transportation, the country development goals of economic and social needs of the service, the user, to secure the economic condition, age and by using technology, international rules and in compliance with EU policies, to provide uninterrupted. Science and technology progress, the economy needs people to change their habits and cultural accumulation, and possibly all of them at the top of the political preferences, and improve access framework is referring to. In general, an investment in transport and the operation to be financed by the state tradition have continued until recently. However, the worldwide increase in the need for transportation investments and public sector of its limited resources, the state as the primary task of the public service has forced the change. In this context, private sector investment in transport infrastructure by the interest of public resources without the need or less fixed by public contributions and the roads are intended to be searched. However, the private sector by the implementation of transport investment opportunities, to provide an important opening, the demand and the private sector increasingly replicated because of limitations in resources, public also needs to contribute is inevitable. Today, construction of new highway each day to reduce motor vehicle traffic in the continuous increase in resources and right in the face of difficulties, the new highway as much of the existing highway superstructure, the future intensive and heavy traffic can provide answers to the maintenance, repair and renewal work as more important. Turkey's Motorway Network maintenance and repair is too high to reach for the requirements of the budget because of limited resources available in our country of resources in a more efficient use, to the motorway network, roads, Pavement Management System implementation has become mandatory to have. Pavement Management System (PMS), limited to an existing budget, to provide the highest gain optimum maintenance / improvement programs to create a priority objective and systematic approach to move. This system, road managers, limited budget available for road improvement in terms of better use to help you decide to minimize the initiative depends on the person.The basic purpose of a pavement management system is to achieve the best value possible for the available public funds and to provide safe, comfortable and economic transportation. Pavement Management System (PMS), are applicable on two levels, namely the network level and the individual (project) level. At the network level, decisions are made on a large group of projects or an entire motorway network regarding what to do (repair, rehabilitation or other measures) and when and where. The individual or project level, on the other hand, is concerned with more specific technical management decisions for the individual projects. Roughness of a motorway is an important parameter which not only indicates the comfort level of ride over a pavement surface, but it is also related to vehicle's vibration, operating speed wear and tear of the wheel, vehicle operating cost. Some of the roughness indices, which are used to quantify the road roughness, are: International Roughness Index (IRI), Mean Panel Rating (MPR), Profile Index (PI), Ride Number (RN), Root Mean Square Vertical Acceleration (RMSVA.)In this study, General Directorate of Turkish Highways as a result of measurement data (IRI and RN) collected with the use of motorways in the pavement when the corruption occurs in the future, to create models (fuzzy logic, regression analyze) to help in the matter of identifying the country in accordance with our conditions, a Pavement Management System (PMS)'s goal is to be established. In this paper, to develop a system for planning of pavement maintenance works on the motorway network in Turkey, on which roughness tests were made by KGM (General Directorate of Turkish Highways) considered. By using the present parameters for the conditions in Turkey (traffic, climate, material features, total thickness of distressed motorways, pavement temperatures etc.) and the measured roughness values (IRI, RN),pavement performance estimation modelling and related to this, a method about establishing a pavement rehabilitation program for the future, is given. In this study, to create models, used two computer programs which above written in MATLAB2008R Fuzzy Logic toolbox and SPSS16. Keywords:, Pavement Management System, fuzzy logic model, IRI, RN
Defining topological relations between topographical features within the scope of 1:25000 scaled geodatabase design
Get PDFÜlkemizde 1:25000 ölçekli sayısal harita üretimi sistemi kapsamında, fotogrametrik vektör veriler üzerinde, kıymetlendirme operatörleri ve bütünleme personeli tarafından fotogrametrik düzenlemeler (birleştirme, alan kapatma, detay kesişimi, fazlalıkların atılması, eksikliklerin tamamlanması vb.) yapılmakta ve detaylar arası ilişkiler tanımlanmaktadır. Gerek kıymetlendirme operatörleri gerekse bütünleme personeli tarafından yapılan veri düzenlemeleri ağırlıklı olarak personelin iş tecrübesine dayanmaktadır. Fakat 1:25000 ölçekli bir pafta içerisindeki vektör veri yoğunluğu, toplanan detay çeşidinin fazlalığı ve detaylar arasındaki ilişkilerin karmaşıklığı göz önüne alındığında, tecrübeli personelin bile tüm detaylar arasındaki ilişkileri kontrol edebilmesinin zor ve zaman alıcı olduğu ve bu maksatla kullanılabilecek bir topolojik tutarlılık kalite kontrol sistemine ihtiyaç duyulduğu değerlendirilmektedir. Bu çalışma ile 1:25000 ölçekli vektör veri tabanı tasarımı çalışmaları kapsamında, topoğrafik veri tabanı kalite kontrol sistemi kurulmasının bir adımı olarak Ulaşım Sınıfı detayları arasındaki topolojik ilişkilerin belirlenmesi, gerekli kuralların geliştirilmesi ve bu kurallara uymayan detayların tespit edilerek operatöre sunulması hedeflenmiştir. Bu maksatla öncelikle mevcut yönetmelikler, üretim talimatları ve konu ile ilgili eski çalışmalar incelenerek topolojik kurallar tespit edilmeye çalışılmıştır. Tecrübeli kıymetlendirme operatörleri ve bütünleme personeli ile görüşmeler yapılmış ve tespit edilen kurallar geliştirilerek yazılı doküman olarak hazırlanmıştır. Yazılı olarak hazırlanan kurallar, ESRI ArcGIS programının hazır araçları kullanılarak ve gerekli kodlar yazılarak kişisel veri tabanı ortamında tanımlanmış, hazırlanan bir arayüz aracılığıyla, kullanıcı etkileşimli olarak sorgulanması ve hataların ArcMap programı üzerinde kullanıcıya sunulması sağlanmıştır. Anahtar Kelimeler: 1:25000 ölçek, topolojik ilişki, topolojik tutarlılık, veri kalitesi, kalite kontrolü.In 1:25000 scaled digital map production system photogrammetric vector data is collected from stereo aerial photograph couples via digital photogrammetric workstations in Soft Plotter KDMS format and transformed into MicroStation DGN format. Some photogrammetric editing operations (merge, clip, feature intersection arrangement, polygon closing, creating missing features, data cleaning etc.) on collected data are carried out by compilation operators via MicroStation Software. Then the data is transferred to completion unit for land completion works. In this unit, the operators correct the feature compilation or assessment errors, complete missing features and collect the attributes (name, usage purpose, feature height etc.), which cannot be detected in compilation phase, on land in 3D shape format by using digital data collection sets. The data that is collected on land are merged with the data that has been collected by compilation operators and transformed into DGN format and. Then some data quality controls are implemented and the data are archived in DGN format. In near feature it is planned to archive the same data also in Shape format. For the cartographic operations and plotting works the data are delivered to the related units. In the data collection workflow stated above, the data arrangement operations by either compilation or completion operators mainly depend on their experiences. There is no written reference for these works. Because of the feature types' excess, the complexity of relations between features and data density in a 1:25000 scaled map, it is assessed that it is very difficult and time consuming even for an experienced operator to control the features' relations. Thus, a need for a topological consistency control system emerges. By designing this control system it is expected that the topological consistency quality of photogrammetric vector data will increase, a valuable feedback will be available for both compilation and completion processes, topological consistency quality control of data in geodatabase, of which design and implementation works are still ongoing, will be possible, as a result of increased data quality, data queries will be more accurate and reliable. In this study which has been directed to improve the quality of 1:25000 scaled topographical vector data, as a part of designing geodatabase quality control system, determining and applying relations between topological features, forming relationship rules, finding out the data which disobey the rules and presenting this disobeying data to operator has been aimed. "Transportation Class" features have been used for this study as a model for the whole thematic classes. At first, existing written regulations, production directions and related previous studies have been scrutinized. Some relationship rules have been determined from these references. Then numerous meetings have been arranged with experienced compilation and completion operators. The rules have been developed by means of these deliberations. After verifying that the studies have come to an end, a document including determined rules has been prepared. In this rules list it has been seen that the operators' contribution has been much more than the reference documents', as it had been expected. Then the rules have been examined again and each of them has been decided whether it would be possible to apply to the system by using ESRI ArcGIS ready tools or it would need some customization codes. These decisions have also been written to document in related feature?s row. Afterwards, the rules which could be applied by using ready tools have been defined in personal geodatabase. For the rules which have needed some scripts, the necessary programs have been prepared in ArcObjects by using Visual Basic for Applications interface of ArcMap software. These programs have provided applying these rules to the system, interactive data query on whole rules and presenting the disobeying data (errors) to the operator. Objects in the real world have very complex relations between themselves. These relations must be determined and modeled as realistic as possible to be able to form the consistency of the collected data sets. Modeling the relations between topographical features in real world is a subject on which research and development studies still go on. It is assessed that with the results of this study, measurable inputs can be achieved which help deciding whether the 1:25000 scaled topographical data model and newly designed geodatabase are convenient, feasible and they can be managed or not. Keywords: 1:25000 scale, topological relation, topological consistency, data quality, quality control
Experimental investigation of the effects of beach drainage on erosion in fine-grained beaches
Get PDFPlajlar ince kumlardan iri kayalara kadar değişen büyüklükte kayaların birikmesiyle oluşmuş jeolojik bölgelerdir. Plajlar kara, hava ve deniz birleşiminde yer almakta olup morfolojileri dalga mekaniği, katı madde özellikleri ve mekaniği, plaj yeraltı suyu akımı ve mekaniği ile rüzgar etkilerinin etkileşimine bağlıdır. Sahil drenajı, sahil altına yerleştirilen perfore drenaj boruları vasıtasıyla dalga ve yeraltı sularının drene edilmesi ve böylece yeraltı su seviyesinin düşürülmesi ile sızma oranının arttırılması prensibine dayanır. Araştırmada ince taneli kuma sahip sahillerde sızma oranının arttırılması ile erozyonun nasıl değişeceği deneysel olarak incelenmiştir. Çalışmanın amacı değişik dalga özelliklerinin etkisinde drenaj borusunun farklı konumlarında profil şeklinin ve drenaj debisinin tayin edilmesidir. Bu amaçla fiziksel bir model geliştirilmiş ve basit analitik çözümler önerilmiştir. Bu çalışmalar daha sonra düzenli dalga koşullarında yapılan laboratuvar çalışmaları ile karşılaştırılmıştır. Drenaj debisinin tahmini, inşaa edilecek su toplama kuyusunun hesabında ve bu kuyudan suları denize deşarj edecek pompa kapasitesinin tayininde kullanılmaktadır. Öte yandan, değişik dalga ve drenaj borusu yerleşim yerleri için erozyon alanının tahmin edilmesi, kıyı duvarları ve kıyı kaplamaları gibi çeşitli yapıların stabilitelerinin belirlenmesi açısından önemlidir. Bu çalışmada hem drenaj debisi hem de erozyon alanı parametrelerinin tahmini için denklemler önerilmiştir. Sahil drenajı ile erozyon alanında azalma yaşanmıştır. Bunun nedeni olarak yer altı su seviyesinin düşmesi ile sızma oranında artma ve buna mukabil katı madde efektif ağırlığında artış söylenebilir. Profil verileri incelendiğinde erozyon alanındaki artışın en önemli nedeni ise dalga tırmanma yüksekliğinde yaşanan azalma görülmüştür. Anahtar Kelimeler: Sahil drenajı, erozyon, stabilizasyon.Beaches play important roles in both the dissipation of wave energy and for the recreational purposes. They are generally in dynamic equilibrium. But, due to increasing industrial activities and population, human interference into the beaches occurs and the dynamic equilibrium deteriorates. In order to control the cross-shore and alongshore sediment transport in eroding beaches, some structures like breakwaters, groins, seawalls are constructed. These structures are composed of massive concrete blocks which lead to loss in aesthetic vision. Moreover, these structures are very difficult to relocate after construction. Beach drainage is an erosion control method studied in-situ, laboratory and numerically and offers an alternative to massive coastal control structures. Main philosophy lying under this method is lowering the water table and increasing the infiltration through the sediment matrix. As the infiltration rate increases, the probability of liquefaction and effective weight reduction of sediments will be reduced. Also, water that infiltrates during the wave runup will lead to reduction in flow velocity during both in runup and run-down phases. This reduction in flow velocity will lead to reduction in shear stresses. Recently, some numerical studies claim that for fine sediments, in case of infiltration, erosion occurs due to offshore migration of sediments. On the other hand, reports of in-situ investigations reveal that, in case of infiltration either the beach accretes or the erosion is reduced. Experiments are conducted in a narrow flume with 22m in length, 1m in width and 80cm in depth. Slope of beach profile is always kept constant (1:5), the profile and drainage flow rate data are measured. The median grain size of the sediment is d50=0.3 mm. The diameter of the drainage pipe is 50mm and is laid all width of the flume. The pipe is perforated in 8mm holes to allow the water suction. Geotextile sheet is wrapped over the pipe to prevent the holes from sediment clogging. 6 drainage pipe locations are determined; beach profiles and drainage flow rates are measured in these locations. Between the beach head and the ground water trench, geotextile filter layer is placed to prevent clogging of the holes, which allow the ground water flow through the beach. Ground water level is always kept constant in all experiments as the same as the still water level. According to the experimental analysis, the waves which have lower height than 5.5 cm do not result in erosion in the profile in no-drain case. The area of the erosion is almost linearly increasing with wave height. In case of drainage, the wave height which does not result in erosion in the profile is observed as 8cm. Center of gravity of the offshore bar migrates landwards as the drainage pipe location approaches the intersection of beach profile and still water line. There is no direct relation between the drainage flow rate and erosion area. The important factor is that whether the runup/rundown wave water or the existing ground water is drained. The ground water is drained as the pipe location migrates landwards. According to the experimental analysis results, the most obvious reduction in the erosion area is observed when the pipe is placed in location (2). When the data measured in location (2) is compared with no-drain data, erosion area reduction rate is reduced when the wave height is increased. When the wave height is increased up to 25 cm, drainage has no advantage to reduce erosion Dimensionless drainage flow rate and dimensionless erosion area parameters are derived analytically by using the data measured in pipe locations of 1, 3, 4 and 5. Derived equations are verified by using locations 2 and 6. The increase in the infiltration rate by lowering the water table leads to reduction in the effective weight of the sediments and decrease in the flow velocity of the runup/rundown swash flows. When the profile graphs are investigated, the main reason for the erosion reduction should be the reduction of the wave runup height. Increase in the infiltration rate leads to reduction of the wave runup wave flow velocity and quantity, resulting in the decrease of runup limit of water waves. In the down-rush phase, the flow velocity is also reduced and the ability to carry sediments is decreased. Keywords: Beach drainage, dewatering, erosion, stabilisation
Aktif görünüm modeline dayalı gürbüz yüz hizalama
Get PDFIn building a face recognition system for real-life scenarios, one usually faces the problem that is the selection of a feature-space and preprocessing methods such as alignment under varying illumination conditions and poses. In this study, we developed a robust face alignment approach based on Active Appearance Model (AAM) by inserting an illumination normalization module into the standard AAM searching procedure and inserting different poses of the same identity into the training set. The modified AAM search can now handle both illumination and pose variations in the same epoch, hence it provides better convergence in both point-to-point and point-to-curve senses. We also investigate how face recognition performance is affected by the selection of feature space as well as the proposed alignment method. The experimental results show that the combined pose alignment and illumination normalization methods increase the recognition rates considerably for all feature spaces. In this paper, we focus on the problems induced by varying illumination and poses. Our primary aim is to eliminate the negative effect of illumination and pose on the face recognition system performance through illumination and pose-invariant face alignment based on Active Appearance Model. Pose normalization is required before recognition in order to reach acceptable recognition rates. We developed AAM based pose normalization method which uses only one AAM. There are two important contributions over the previous studies. By using the proposed method: One can synthetically generate appearances for different poses when only frontal face image is available. One can generate frontal appearance of the face when there is only non-frontal face image is available. The same variation in pose imposes similar effect on the face appearance for all individuals. Deformation mostly occurs on the shape whereas the texture is almost constant. Since the number of landmarks in AAM is constant, the wireframe triangles are translated or scaled as pose changes. So as we change pose, only wireframe triangles undergo affine transformation but the gray level distribution within these triangles remains the same. One can easily generate frontal face appearance if AAM is correctly fitted to any given non-frontal face of the same individual provided that there is no self-occlusion on face. Self-occlusion usually is not a problem for angles less than ±45. For 2D pose generation, we first compute how each landmark point translates and scales with respect to the corresponding frontal counterpart landmark point for 8 different poses, and obtain a ratio vector for each pose. We use the ratio vector to create the same pose variation over the shape of another individual. Appearances are also obtained through AAM using synthetically generated landmarks. It is important to note that the generated faces contain no information about the individual used in building the ratio matrix. An AAM model trained by using only frontal faces can only fit into frontal faces well and fail to fit into non-frontal faces. Our purpose here is to enrich the training database by inserting synthetically generated faces at different poses so that AAM model trained by frontal faces can now converge to images at any pose. In this paper we developed AAM based face alignment method which handles illumination and pose variations. The classical AAM fails to model the appearances of the same identity under different illuminations and poses. We solved this problem by inserting histogram fitting based normalization into the searching mechanism and inserting different poses of the same identity into the training set. From the experimental results, we showed that the proposed face restoration scheme for AAM provides higher accuracy for face alignment in point-to-point error sense. Recognition results based on PCA and LDA feature spaces showed that the proposed illumination and pose normalization outperforms standard AAM. Keywords: Face alignment, active appearance models, illumination invariant face recognition.Yüz görünümündeki şekil ve doku değişimine bağlı farklılıklar yüz tanıma problemini oldukça zor hale getirmektedir. Bireyler arası yüz görünüm farklılıklarının fazla olmasına karşın, her bireyin kendi yüz görünümünü farklı hale getirecek değişimlerde mevcuttur. Özellikle aydınlatma ve poz değişimleri yüz tanıma sistemlerinin başarımını etkileyen zorlukların başında gelmektedir. Bu çalışmada otomatik yüz hizalama için aydınlatma ve poz değişimlerine karşı gürbüz yeni bir yöntem tanıtılmıştır. Klasik aktif görünüm modeli (AGM) yapısına yüz için özelleştirilmiş aydınlatma normalizasyonu eklenerek AGM’nin farklı aydınlatma koşullarındaki arama ve yakınsama performansını arttıran yeni bir yöntem önerilmiştir. AGM ile yüz bölütlemede, özgün yüz aydınlatma normalizasyonunu AGM bükme (warping) işleminden hemen sonra ve her çevirimde uygulayarak aydınlatma değişimlerine karşı gürbüz bir model oluşturulmuştur. Yöntem giriş olarak verilen farklı aydınlatılmış ve farklı bir poza sahip yüz görüntüsünü hem iyileştirmeye hem de hizalamaya çalışmaktadır. Ayrıca tam karşıdan çekilmiş tek bir yüz görüntüsünden, o kişinin farklı pozlara sahip görüntülerini sentezleyen bir yöntem tanıtılmış ve sentetik olarak sentezlenen poz verileri ile AGM şekil uzayı güçlendirilerek poz değişimlerine karşı gürbüz bir yöntem önerilmiştir. Önerilen yöntemde, model eğitimi için aynı bireyin farklı aydınlatma ve poza sahip görüntülerine ihtiyaç duyulmamaktadır. Önerilen yöntemde aydınlatma değişimlerine karşı bağışık bir yapı oluşturulması için karmaşık aydınlatma modelleri gerekmemektedir. Deneysel çalışmalardan da görüleceği gibi önerilen yöntem, farklı aydınlatma ve pozlarda bile klasik AGM’ye göre oldukça iyi sonuçlar vermiştir. Anahtar Kelimeler: Yüz hizalama, aktif görünüm modelleri, aydınlatmadan bağımsız yüz tanıma
Web-based integrated construction management system model
Get PDFİnşaat yapım süreci çok sayıda proje katılımcısını, değişik formlarda ve sorumluluklarda proje organizasyonlarını ve farklı tiplerde bilgisayar uygulamalarını içerir. Bu özellikler uygulamalardaki entegrasyona dayanan büyük miktarda veri değişimi ve bilgi paylaşımı ihtiyacını ortaya çıkarmaktadır. Yapı üretim sürecinin her aşamasını kapsayan ve katılımcılar arasındaki iletişim kopukluğunu sanal ortamda ortadan kaldıran “Web-tabanlı Bütünleşik Yapım Yönetim Sistemi Modeli” geliştirilmiştir. Önerilen sistem ile yönetim kademelerine güncel, doğru ve hızlı veri akışı sağlama, ayrık ortamlardan bilgiye kolay erişme ve çoklu-proje ortamın-da etkin süreç yönetimi hedeflenmiştir. Bu çalışmada önerilen modelin inşaat yapım sürecinin tüm aşamalarındaki proje yönetimine ve sektörün gelişimine sağladığı katkılar tartışılacaktır.The construction process involves a large number of participants, various forms of project organisation, and the use of numerous different types of computer applications. These characteristics bring forth the need for intensive data exchange and information sharing based on the integration of various applications. Different types of construction projects undertaken by the ITU Construction Works Office are continuing to expand and a serious need for the management of all construction related activities are recognised. With such a rapid spurge of projects, a need is recognised for a system that would ensure the effective management of the ITU's campus construction projects. This process involves the integration of such information in a format that can be transferred to the level of the Rector for effective decision-making. The objective of this study is to develop an integrated data management tool including decision-support utilities for communicating, organising and managing project information using web-based technology and the network. By integrating data, extracted from the specific software packages, the system generates a variety of reports at the multiple project level for multi-task decisions to achieve completion of the multi-projects on time within budget. The paper concludes with a discussion of how the proposed system contributes to the development of the construction industry
The relation between social and economical indicators of the cities in Turkey
Get PDFBirleşmiş Milletler Kalkınma Programının yürüttüğü sosyal ve ekonomik göstergeler kullanılarak yapılan insani kalkınma indeksi çalışmalarında, Türkiye ekonomik olarak daha geri ülkelerin bile altında çıkmıştır. Bu çalışmada sosyal ve ekonomik göstergeler arası ilişkilerin illere göre nasıl değiştiğini açıklamak amaçlanmıştır. Sosyo-ekonomik yapıları ortaya çıkarmak için faktör analizi kullanılmıştır. 80 il bazında 30 değişken, 3 faktör altında toplanmıştır. Araştırmada, birinci faktör sonucuna göre; bazı kentler ekonomik olarak daha gelişmiş iken, bazı kentler sosyal olarak daha ileri düzeyde çıkmıştır. İkinci faktör sonucuna göre; sanayi üretiminde verimlilik önem kazanmaktadır. Üçüncü faktör sonucunda ise, GAP bölgesine yapılan yatırımların etkisi görülmüştür.The purpose of the study was to establish the factors which determine the level of socioeconomic development of the cities in Turkey. In the group factor analysis carried out to analyze the differentiation in the socioeconomic structures of the cities in Turkey, 80 cities could only be described on the basis of 30 variables and under 3 factors. The factors, according to the variables with more predicates, have been named, the first, as “Technical and Social Infrastructure Factor”, the second as “Manufactures Industry Production and Private Sector Venture Factor” and the third as “Agricultural Production, Tourism and Business Services Factor”. The result of the research showed that, as a result of the first factor, some cities are economically more developed and some are socially more developed. For this reason, socioeconomic development can be ensured with investments in the socially developed cities towards qualified workforce. According to the result of the second factor, productivity in the industrial production gains importance. As a result of the third factor, the effect of the investments made in the GAP region has been seen. Gaziantep situated in GAP region has been found to have an important polar development dynamics. In the third factor, tourism has been found important. A tourism planning may be made at the axle to interconnect Antalya, in the western Mediterranean, Adıyaman, Gaziantep, Mardin, and Van in the Southern-east
The role of the landmarks in the legibility of holiday villages
Get PDFBu çalışmada mimari çevrenin okunabilirliğinde önemli bir bileşen olan “çevre işaretleri”nin turizm amaçlı bir yerleşme türü olan “tatil köyleri”nin mekansal olarak okunmasındaki rolü değerlendirilmiştir. Değerlendirme için Antalya İli Belek beldesinden üç adet tatil köyü seçilmiş, seçilen tatil köylerinde çevre işaretlerinin bireyler tarafından seçimini tespit etmek için anket yöntemi kullanılmıştır. Anket bireyin tatil köyü ile ilgili hatırladığı elemanların açık uçlu sorularla ve “bilişsel harita” çizimi ile tespitini sağlamıştır. Buna göre bir tatil köyünde, sahip olduğu rekreasyon ve dinlenme amaçlarına bağlı olarak bireylerin tespit ettikleri çevre işaretleri ortaya çıkarılmıştır. Bu veriler bize yeni bir tatil köyü tasarımında yüksek düzeyde okunabilirlik sağlanmasında çevre işaretlerinin ne tür özelliklere sahip olması gerektiği ile ilgili birtakım sonuçlar sunmaktadır.In this study the role of the "landmarks" which are one of the most important components in the legibility of an architectural environment has been evaluated in the spatial reading of the resort type "holiday village". Legibility means the ease of recognition and organization of parts of an urban space. Theoretically it has six components: landmarks, routes, nodes, edges, districts and complexity . Landmark is one and most important organizer of this process. A legible space rescues from being lost, eases quick move, develops a common sense psychology, gives emotional trust, increases potential density in experience and decreases chaos, anger and unconscious crowd in space. Landmarks helps to decrease all negative space effects on human psychology. In an urban design all the elements to be selected as a landmarks have to be found out. These findings can guide a new design to be much more legible and preferred. One of the methods of this kind of research is a case study in that environment. As an urban environment three holiday villages in the Mediterranean shores of Antalya-Belek have been selected for this evaluation. A questionnaire that determined the architectural elements chosen by the subject with open-ended question types and a "cognitive map" drawing exercise has been used. As a result the landmarks with relation to all recreation and resting facilities have been found out. These data have given us conclusion on the features of landmarks to develop a high level legibility for a holiday village settlement design study
Physical and economical restructuring of central business districts (CBD); sample: Eskişehir
Get PDFBu çalışmada, kent içinde önemli bir konuma sahip merkezi iş alanının (MİA) oluşumunu ve gelişimini etkileyen faktörler ve bunlar arasındaki ilişkiler genel olarak irdelenmiştir. MİA dokularının, fonksiyonel ve mekansal olarak tekrar canlandırılarak, kullanım ve değişim değerlerinin artırılmasıyla birlikte, çağdaş gereksinimlere cevap verebilecek hale getirilmesi gereklidir. Özellikle gelişmiş ülkelerdeki hem fiziksel, hem de ekonomik yönden uygulanan yeniden yapılanma projeleri ve sonuçları bunu ortaya koymaktadır. Çalışma kapsamında; “Merkezi İş Alanlarının fiziksel ve ekonomik olarak yeniden yapılanması: Eskişehir Örneği” üzerinde yapılan araştırmalar değerlendirilerek elde edilen sonuçların, geleceğe yönelik şehir planlama çalışmaları ile stratejik politika ve alınacak önlemler açısından, yararlı ve yol gösterici olabileceği düşünülmektedir.The factors and their interrelations that affect the existence and development of central business districts (CBD) as important items in the city are generally examined in the approach that is brought into being by this study. As it is known, cost of the product and competitive environment have a pretty effective role in terms of city population, economy, social and city economic infra-structure that have important effects on the development of central business districts and their inner commercial activities. Consequently, this causes city economy and physical appearance to wear out and become outdated with social change. Within the process of rapid urbanization, the effect of the physical growth of urban spaces in CBD is researched in this study. The restructuring of CBD according to their physical and economical contents is analyzed in the case of Eskisehir. The results of this analysis are considered to be guide and useful for the future city planning in terms of strategic policy and proper measures. By analyzing spatial progress of CBD in certain period that have a multi-varied structure with service sectors like management, supervision, commerce, social and cultural activities as a reflection of city of Eskisehir socio-economic base, to point out directions of the progress, factors and their effects that cause the progress and to make the decisions of progress in the city-land of Eskisehir for next 30 year term are aimed
Data sources:
Access Repository Dashboard
Do you manage itüdergisi (E-Journals - İstanbul Teknik Üniversitesi, Istanbul Teknik Uniersity., İTÜ)? Access insider analytics, issue reports and manage access to outputs from your repository in the CORE Repository Dashboard!