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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Effects Of Soil Structure Interaction And Base Isolated Systems On Seismic Performance Of Foundation Soils

Soyoz, Serdar 01 July 2004 (has links) (PDF)
In this thesis primarily structural induced liquefaction potential was aimed to be analyzed. Also the effect of base isolation systems both on structural performance and liquefaction potential was studied. FLAC software was chosen for the analyses so that structure and soil could be modeled together. By these means the soil structure interaction effects were also examined. Four different structures and three different sites were analyzed under two different input motions. All the structures were also analyzed as base isolated. It was mainly found that depending on the structural type and for a certain depth the liquefaction potential could be higher under the structure than the one in the free field. Also it was concluded that base isolation systems were very effective for decreasing the story drifts, shear forces in the structure and liquefaction potential in the soil. It was also found that the interaction took place between structure, soil and input motions.
82

Assembly Line Balancing With Task Paralleling

Kaplan, Ozlem 01 September 2003 (has links) (PDF)
In this study, we consider single model deterministic Assembly Line Balancing problem with task paralleling. The objective is to minimize the total cost which is composed of station opening cost and task dependent equipment cost. A branch and bound algorithm that allows two-level task paralleling is proposed. A heuristic algorithm is also developed both for obtaining efficient upper bounds to branch and bound and for achieving good approximate solutions for large sized problems. Computational experiments are conducted to investigate the effects of experimental parameters on the cost-related and algorithm-related performance measures. The exact algorithm results are compared to the proposed heuristic algorithm results, station paralleling results and optimal solutions without paralleling.
83

Generalized Beam Angle Statistics For Shape Description

Tola, Omer Onder 01 October 2004 (has links) (PDF)
In this thesis, we introduce a new shape descriptor and a graph based matching algorithm to detect a template shape in an image that contains a single object. The shape descriptor, Generalized Beam Angle Statistics, GBAS is obtained with the generalization of the boundary based shape descriptor, Beam Angle Statistics, BAS cite{BAS}. GBAS improves BAS so that it can compute the feature vector of a boundary point without the requirement of the parametric boundary representation. This way, it can be used in matching an individual edge pixel with a boundary point of template shape, even if it is not possible to extract the shape boundary in the image with the available techniques. Given a template shape, the matching algorithm solves the correspondence problem between the sampled boundary points of the template and the edges of the query image, using the GBAS feature vectors and the spatial information of edges. The match graph represents the correspondence problem and the optimum path on this graph gives the solution of it. Optimum path is found using a polynomial time algorithm that is based on the dynamic programming approach. In the experiments, we show that the proposed shape descriptor is very powerful and the matching algorithm is capable of detecting a template shape in edge detected images under a variety of transformations and noise.
84

Settlement Behaviour Of Concrete Faced Rockfill Dams: A Case Study

Ozkuzukiran, Riza Savas 01 January 2005 (has links) (PDF)
In this study settlement behaviour of K&uuml / rt&uuml / n dam, which is the first concrete faced rockfill dam in Turkey, is investigated. Two dimensional plane strain finite element analyses are carried out in order to determine the total stresses and displacements during construction and reservoir filling conditions. Hardening soil model is used in order to represent the non-linear, inelastic and stress dependent behaviour of rockfill material. Material model parameters are selected mainly referring to the previous studies on the dams consisting of similar materials. Calculated stresses and settlements are compared with the observed values and in general, they were found to be in good agreement for the construction stages. It is seen that, due to the relatively narrow valley and steep abutment slopes, arching is a significant parameter as far as the stresses and settlements are concerned. For the reservoir impounding condition, calculated settlements were found to be slightly larger than the observed values, which may indicate that during the reservoir impounding, the rockfill embankment behaves in a stiffer manner as compared to that of during construction stages.
85

Mechanical Properties Of Cfrp Anchorages

Ozdemir, Gokhan 01 February 2005 (has links) (PDF)
Due to inadequate lateral stiffness, many reinforced concrete buildings are highly damaged or collapsed in Turkey after the major earthquake. To improve the behavior of such buildings and to prevent them from collapse, repair and/or strengthening of some reinforced concrete elements is required. One of the strengthening techniques is the use of CFRP sheets on the existing hollow brick masonry infill. While using the CFRP sheets their attachment to both structural and non-structural members are provided by CFRP anchor dowels. In this study, by means of the prepared test setup, the pull-out strength capacities of CFRP anchor dowels are measured. The effects of concrete compressive strength, anchorage depth, anchorage diameter, and number of fibers on the tensile strength capacity of CFRP anchor dowel are studied.
86

Operational Hydrological Forecasting Of Snowmelt Runoff By Remote Sensing And Geographic Information Systems Integration

Tekeli, Ahmet Emre 01 June 2005 (has links) (PDF)
Snow indicates the potential stored water volume that is an important source of water supply, which has been the most valuable and indispensable natural resource throughout the history of the world. Euphrates and Tigris, having the biggest dams of Turkey, are the two largest trans-boundary rivers that originate in Turkey and pass throughout the water deficit nations Syria, Iran, Iraq and Saudi Arabia bringing life as well as water all their way. Snowmelt runoff originating from the mountains of Eastern Turkey accounts for 60 to 70 % of total annual discharge observed in Euphrates and Tigris. For an optimum operation of the dams, maximizing energy production, mitigation of floods and satisfying water rights, hydrological models which can both simulate and forecast the river discharges of Euphrates and Tigris are needed. In this study a hydrological model, snowmelt runoff model (SRM), is used in conjunction with remote sensing and geographic information systems to forecast the river discharges in the headwaters of Euphrates River, Upper Euphrates Basin. NOAA and MODIS satellite images were used to derive the snow covered area (SCA) information required by SRM. Linear reduction methodologies based on accumulated air temperature, with constant or varying gradient, were developed to get the continuous daily SCA values from the discrete daily satellite images. Temperature and precipitation forecasts were gathered from two different numerical weather prediction models, namely European Center for Medium Range Weather Forecasts (ECMWF) and Mesoscale Model Version 5 (MM5) from Turkish State Meteorological Services. These data sets provided t+24 hour forecasts of both temperature and precipitation. Temperature, precipitation and SCA information are fed into SRM. Discharge forecasts obtained from the model outputs are compared with the observed values. The overall performance of the model was seen as promising. Possible reasons of the mismatches between the forecasted and observed values are searched. Experiences gained throughout the study are summarized and recommendations on further forecast studies are mentioned.
87

Legal Aspects Of Ict Implementation In Turkish Construction Industry

Ciftci, Caglar 01 July 2005 (has links) (PDF)
With increasing awareness of gains and importance of the strategic use of Information and Communication Technologies (ICT), the implementation rate of ICTs in construction sector is increasing. However, these technologies have not been covered by legal and contractual practices. The industry needs to implement application frameworks and legal re-structuring of the existing related laws and regulations to use ICT in a legal and contractually valid environment. In this thesis, an EU funded project, eLEGAL / which defines a framework for legal conditions and contracts regarding the use of ICT in construction industry, is selected as a model project to address legal and contractual issues regarding ICT use in Turkish construction industry. Moreover, the applicability of this project&rsquo / s results are discussed by using real cases and defining the barriers, opportunities, methods and tools to use ICT legally admissible in Turkish construction industry.
88

Use Of Satellite Observed Seasonal Snow Cover In Hydrological Modeling And Snowmelt Runoff Prediction In Upper Euphrates Basin, Turkey

Sorman, Ali Arda 01 June 2005 (has links) (PDF)
Snowmelt runoff in the mountainous eastern part of Turkey is of great importance as it constitutes 60-70% in volume of the total yearly runoff during spring and early summer months. Therefore, forecasting the amount and timing of snowmelt runoff especially in the Euphrates Basin, where large dams are located, is an important task in order to use the water resources of the country in an optimum manner. The HBV model, being one of the well-known conceptual hydrological models used more than 45 countries over the world, is applied for the first time in Turkey to a small basin of 242 km2 on the headwaters of Euphrates River for 2002-2004 water years. The input data are provided from the automatic snow-meteorological stations installed at various locations and altitudes in Upper Euphrates Basin operating in real-time. Since ground based observations can only represent a small part of the region of interest, spatially and temporally distributed snow cover data are acquired through the use of MODIS optical satellite. Automatic model parameter estimation methods, GML and SCE_UA, are utilized to calibrate the HBV model parameters with a multi-objective criteria using runoff as well as snow covered area to ensure the internal validity of the model and to generate a Pareto front. Model simulations show that the choice of study years and timing of satellite images affect the results and further suggest that more study catchments and years should be included to achieve more comprehensible conclusions. In the second part of the study, the calibrated HBV model is applied to forecast runoff with a 1-day lead time using gridded input data from numerical weather prediction models of ECMWF and MM5 for the 2004 snowmelt period. Promising results indicate the possible operational use of runoff forecasting using numerical weather prediction models in order to prevent or at least take precautions before flooding ahead of time.
89

Comparison Of International Federation Of Consulting Engineers And General Specification For Public Works Contracts From Risk Management Perspective

Usta, Ergun 01 August 2005 (has links) (PDF)
Contractors have to construct the projects efficiently in accordance with the contract provisions when they accept a contract. All construction projects involve risk and there is no possibility to eliminate all the risks associated with a specific project. Management of risk requires identification and analysis of risk factors. After this risk assessment step, proper response strategies have to be developed so that an optimum risk-reward structure is ensured. Contracts are the grounds where risk allocation schemes between parties are settled and risk-reward mechanisms are defined. Since contractors are usually unable to influence the contract conditions and clauses, they should understand which risks they are retaining under contract conditions. Thus, succesful management of risk requires understanding of contract clauses and identification of secondary risk factors created due to poorly defined contract clauses. The aim of this thesis is to investigate standard conditions of contract, namely FIDIC and GSPW, which are the most widely utilised contracts by the Turkish contractors, from the risk management point of view. For this purpose an interview form is prepared and interviews are conducted using this structured form. Implications of the contract clauses for the risk management strategy of contractors are discussed based on interview findings. The basic philosophy of FIDIC and GSPW are investigated so that necessary suggestions for the contractors can be made considering the risk allocation schemes defined in these documents.
90

Anchorage Strength Of Fiber Reinforced Polymers

Camli, Umit Serdar 01 December 2005 (has links) (PDF)
Fiber reinforced polymers (FRPs) have gained popularity in upgrade projects for reinforced concrete structural elements within the last decade because of its ease of application and high strength-to-weight ratio. In the design of an effective retrofitting solution by means of an FRP system, the anchorage capacity has an important role. This study presents the results of an experimental program conducted to determine the strength of carbon fiber reinforced polymers (CFRPs) bonded to concrete prisms or hollow clay tiles that are finished with or without plaster. In the experimental program, different types of anchorage methods were tested in a double shear push-out test setup. A simple and effective strength model is proposed for strip type anchorages based on the existing analytical models and experimental observations from this study. This new model is suitable for determining the design capacity of CFRP-to-concrete and CFRP-to- hollow clay tile joints with or without plaster and accounts for the presence of embedment and concrete strength. Obtained results by using this model were found to closely match with the experimental observations.

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