Earthquake is one of the most destructive natural disasters on earth. Rapid and reliable post-quake damage assessment has an important role to reduce the drastic effects of an earthquake by setting the responsible agencies in motion. In this study, the collapsed buildings due to earthquake were detected from post-event aerial images. Two approaches were proposed to detect the collapsed buildings. These approaches were implemented in a selected urban area of Golcuk. The first approach was based on the analysis of shadow casting edges. First, the shadow casting edges of the buildings were identified and a buffer zone was generated for each building polygon along these edges. Then, the shadow regions were detected using the watershed segmentation algorithm. This was followed by measuring the agreement between the shadow producing edges of the buildings and their corresponding shadows. Of the 284 buildings analyzed, 229 were successfully labeled as collapsed or un-collapsed providing an overall accuracy of 80,63%.In the second approach, a two-branch method based on building light intensities and the gradient orientation was used. In the first branch, an intensity threshold was determined and applied to building image patches. Then, a pixel ratio was computed to categorize the buildings. In the second branch, a series of processings were carried out including the smoothing of the building image patches and the determination of the magnitude and the orientation of the gradient. Then, an optimum angle threshold was determined to label the buildings. The final decision about the condition of a building was made by integrating the two branches. Of the 284 buildings analyzed, 254 were correctly labeled providing an overall accuracy of 89,44%. The same assessments were repeated after generating a one-pixel wide buffer zone around the building polygons and an overall accuracy of 90,85% was obtained. The results of the proposed approaches prove that the collapsed buildings caused by the earthquake can be successfully detected from post-event aerial images.

In agent based systems, especially in autonomous mobile robots, modelling the environment and its changes is a source of problems. It is not always possible to effectively model the uncertainity and the dynamic changes in complex, real-world domains. Control systems must be robust to changes and must be able to handle these uncertainties to overcome this problem. In this study, a reactive behaviour based agent control system is modelled and implemented. The control system is tested in a navigation task using an environment, which has randomly placed obstacles and a goal position to simulate an environment similar to an autonomous robot&rsquo / s indoor environment. Then the control system was extended to control an agent in a multi-agent environment. The main motivation of this study is to design a control system which is robust to errors and easy to modify. Behaviour based approach with the advantages of fuzzy reasoning systems is used in the system.

ABSTRACT TRUSTED MAIL GATEWAY AYLA, Erkut Sinan M.S., Department of Computer Engineering Supervisor: Dr. Attila &Ouml / zgit December 2004, 135 pages The study aims to make contribution to solve mail security problems. The Trusted Mail Gateway provides a domain with the basic security services that are message integrity, confidentiality, non&amp / #8208 / repudiation, origin authentication and availability while message (e&amp / #8208 / mail) being delivered through the Internet. It generates S/MIME digital signatures and performs S/MIME encryption on behalf of the domain using secret key cryptography and public&amp / #8208 / key techniques and generating Cryptographic Message Syntax (CMS) data to provide origin authenticity, integrity and v confidentiality. It applies anti&amp / #8208 / virus control and protection, spam filtering and content check to both incoming mails to the domain and outgoing mails from the domain to prevent attacks against availability. Also, the Trusted Mail Gateway provides intra&amp / #8208 / domain security. It keeps e&amp / #8208 / mail messages in corresponding mailboxes as encrypted messages. Trusted Mail Gateway processes all the mails passing through and records processing results in database as notary information. Moreover, it establishes trust relations with other trusted domains and exchanges notary information with them via a secure channel. Keywords: S/MIME, security services, mail protocols, domain, notary

Web services introduce a new paradigm for distributed computing, and the technology that it introduces constructs a new type of Web application. Web services can be described as any software that makes its discovery and invocation available over the Internet, and uses a standardized XML messaging system. The term peer-to-peer refers to a class of decentralized systems enabling the access of shared resources available on peers that are acting both as client and as server. In this work, a peer-to-peer approach is used to expoit Web service technologies by providing Web service security for JXTA peer-to-peer networks. JXTA is a network programming environment that has particularly been designed for the peer-to-peer platform. In order to achieve the goal of secure Web services, the specifications &ldquo / WSSecurity&rdquo / , &ldquo / XML Key Management Specification&rdquo / , &ldquo / WS-Trust&rdquo / and &ldquo / WSSecurityPolicy&rdquo / are exploited. &ldquo / WS-Security&rdquo / is primarily a specification for an XML-based security metadata container, and is a building block for the specifications &ldquo / WS-Trust&rdquo / and &ldquo / WS-SecurityPolicy&rdquo / . &ldquo / WS-Trust&rdquo / defines the process of how to acquire security tokens. Within the peer-to-peer network that is proposed with this work, a peer is dedicated to act as a &ldquo / trusted third party&rdquo / and to manage the processes for incorporating the security of public-key infrastructure, which is defined by &ldquo / XML Key Management Specification&rdquo / . In addition, the same peer is dedicated to manage to acquire security tokens, which is defined by &ldquo / WS-Trust&rdquo / . As for &ldquo / WS-SecurityPolicy&rdquo / , Web service invoking peers conform to this specification that specifies how to define security assertions stating Web service provider&rsquo / s preferences and requirements. This work realizes and achieves the necessity of bringing together the technologies mentioned above in order to propose an architecture of secure SOAP messaging for Web service invocation in peer-to-peer environment that is provided by the JXTA framework. The work presented in this thesis is realized as a part of the SATINE project funded by the European Commission.

Creating realistic human animations is a difficult and time consuming job. One of the best solutions known is motion capture, which is an expensive process. Manipulating existing motion data instead of capturing new data is an efficient way of creating new human animations. In this thesis, we review the current techniques for animation, navigation and ways of manipulating motion data. We discuss strengths and weaknesses of interpolation techniques for creating new motions. Then we present a system that uses existing motion data to create a motion graph and automatically creates new motion data for character navigation suitable for user requirements. Finally, we give experimental results and discuss possible uses of the system.

Modern information systems strive to provide effective use of resources. Supplied with analysis tools, geographical information systems (GIS) can serve its stakeholders with minimal requirements. In this study, GIS capabilities were employed for Turkish Flora. Data related with the threatened plants that are indigenous to Turkey were gathered from the relevant literature and reshaped into a dataset in which spatial locations were represented in a geographically referenced format. Afterwards, this output was used to investigate the affects of different factors on the distribution patterns of these plants by means of functions of GIS and multivariate analysis. At last, overlay analysis was employed in order to reveal the congruence between official protection reserves, spatial locations of the plants in danger and areas of importance for other elements of wildlife specifically birds. Outcomes of the study is three-fold. First of all, a simple algorithm was established which can be used in the formation of a unified database of widely distributed floristic data in Turkey. Geographically referenced data and the analysis results produced in the study is another value added for Turkish botanics. From another perspective, effectiveness of GIS in handling different types of non-standard data were scrutinized. Overlay analysis of locations of the plants and the protection reserves constituted the managerial aspect of the study by pointing large gaps in the actual protection coverage and proposing candidate regions for official reserve choices of the future. In essence, GIS was deemed to be an effective tool for parties working on non-standard spatial data.

The aim of this study is to introduce a real-world timetabling problem that exists in some private schools in Turkey and to solve such problem instances utilizing memetic algorithms. Being a new type of problem and for privacy reasons, there is no real data available. Hence for benchmarking purposes, a random data generator has been implemented. Memetic algorithms (MAs) combining genetic algorithms and hill-climbing are applied to solve synthetic problem instances produced by this generator. Different types of recombination and mutation operators based on the hierarchical structure of the timetabling problem are proposed. A modified version of the violation directed hierarchical hill-climbing method (VDHC), introduced by A. Alkan and E. Ozcan, coordinates the process of 12 different low-level hill-climbing operators grouped in two distinct arrangements that attempt to resolve corresponding constraint violations. VDHC is an adaptive method advocating cooperation of hill-climbing operators. In addition, MAs with VDHC are compared with different versions of multimeme algorithms and pure genetic algorithms. Experimental results on synthetic benchmark data set indicate the success of the proposed MA.

This study first introduces an order-free chromosome encoding to enhance the performance of genetic algorithms by learning the linkage of building blocks in non-binary encodings. The method introduces a measure called affinity which is based on the statistical properties of gene valuations in the population. It uses the affinity values of the local and global gene pairs to construct a global permutation with tight building block positioning. Method is tested and experimental results are shown for a group of deceptive and real life test problems. Then, study proposes a gene level concurrency model where each gene position is implemented on a different process. This combines the advantages of implicit parallelism and a chromosome structure free approach. It also helps implementation of gene reordering method introduced and probably other non-linear chromosome encodings.

This thesis proposes an efficient method to accelerate ray based volume rendering with texture slabs using programmable graphics hardware. In this method, empty space skipping and early ray termination are utilized without performing any preprocessing on CPU side. The acceleration structure is created on the fly by making use of depth buffer efficiently on Graphics Processing Unit (GPU) side. In the proposed method, texture slices are grouped together to form a texture slab. Rendering all the slabs from front to back viewing order in multiple rendering passes generates the resulting volume image. Slab silhouette maps (SSM) are created to identify and skip empty spaces along the ray direction at pixel level. These maps are created from the alpha component of the slab and stored in the depth buffer. In addition to the empty region information, SSM also contains information about the terminated rays. The method relies on hardware z-occlusion culling that is realized by means of SSMs to accelerate ray traversals. The cost of generating this acceleration data structure is very small compared to the total rendering time.

This thesis is about software project scheduling and use of earned value method on software projects. As a result of the study, a solution for software project scheduling problems is proposed. A mathematical formulation, developed using integer programming method, is at the heart of the solution. Objective of the formulation is to minimize the development costs consisting of direct labor cost, indirect costs and probable penalty costs. The formulation takes the capability and compatibility variances among resources into account whereas contemporary approaches mostly focus on resource availability. Formulation is of type discrete time and takes the time span to be searched as input. Therefore a heuristic approach has been developed for providing time span input to the models developed using the formulation. The heuristic approach has been proven to be calculating a time span that does not hinder achieving the absolute optimum schedule and shortens the solution time of the integer programs. The heuristic approach and problem formulation have been incorporated into a computer program that generates integer programs and heuristic solutions. This thesis also describes a method for preparing an earned value plan, based on the scheduling solution defined. The method aims to help project managers in determining the status of their projects and deciding whether any corrective action is required or not. Besides the method, approaches for incorporating indirect costs and penalty costs, which are not explicitly discussed in literature, into final cost estimation have been described.