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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.
551

A Security Management System Design

Onder, Hulusi 01 July 2007 (has links) (PDF)
This thesis analyzes the difficulties of managing the security of an enterprise network. The problem that this thesis study deals with is the central management of a large number and variety of services that provide organization-wide network and information security. This study addresses two problem areas: how to better manage the security of a network, and how to explain the security issues to upper management better. The study proposes a Security Management System (SMS) to be used for network security management, monitoring and reporting purposes. The system is a custom made, central management solution, which combines the critical performance indicators of the security devices and presents the results via web pages.
552

Impact Of Damper Failure On Vehicle Handling During Critical Driving Situations

Beduk, Mustafa Durukan 01 November 2009 (has links) (PDF)
Capturing what is going on and what may happen related to vehicle handling behaviour in cases of desired or non-desired actions and interventions has a crucial importance. Strategies implemented to improve vehicle stability or algorithms and control modules designed to compensate the non-desired effects on handling behavior may appear to be inadequate as the vehicle goes through uncountable experiences. The importance of understanding and introducing the possible sources of undesired effects which may be encountered throughout driving action cannot be underemphasized. One of the possibilities that may lead the driver face with unexpected results concerning vehicle&rsquo / s handling is suspension damper failure, which has not yet been dealt with adequately in the literature. The fast developing technology and consequently the expanding utilization of chassis electronics and electronic vehicle components make the investigation of damper failure phenomenon essential since reliability decreases by the continuously increasing introduction of electronic means. In this study, possible failure types of dampers including electrical failure are taken into account, their effects on vehicle stability under critical driving conditions are examined. Shortcomings and comments are made on criticality of failed damper and its failure point. This work as a result, constitutes a particular contribution to the literature in that it brings up a concrete knowledge to the stated research area.
553

Identification Of Low Order Vehicle Handling Models From Multibody Vehicle Dynamics Models

Saglam, Ferhat 01 January 2010 (has links) (PDF)
Vehicle handling models are commonly used in the design and analysis of vehicle dynamics. Especially, with the advances in vehicle control systems need for accurate and simple vehicle handling models have increased. These models have parameters, some of which are known or easily obtainable, yet some of which are unknown or difficult to obtain. These parameters are obtained by system identification, which is the study of building model from experimental data. In this thesis, identification of vehicle handling models is based on data obtained from the simulation of complex vehicle dynamics model from ADAMS representing the real vehicle and a general methodology has been developed. Identified vehicle handling models are the linear bicycle model and vehicle roll models with different tire models. Changes of sensitivity of the model outputs to model parameters with steering input frequency have been examined by sensitivity analysis to design the test input. To show that unknown parameters of the model can be identified uniquely, structural identifiability analysis has been performed. Minimizing the difference between the data obtained from the simulation of ADAMS vehicle model and the data obtained from the simulation of simple handling models by mathematical optimization methods, unknown parameters have been estimated and handling models have been identified. Estimation task has been performed using MATLAB Simulink Parameter Estimation Toolbox. By model validation it has been shown that identified handling models represent the vehicle system successfully.
554

Concurrent design of facility layout and flow-based department formation

Chae, Junjae 17 February 2005 (has links)
The design of facility layout takes into account a number of issues including the formation of departments, the layout of these, the determination of the material handling methods to be used, etc. To achieve an efficient layout, these issues should be examined simultaneously. However, in practice, these problems are generally formulated and solved sequentially due to the complicated nature of the integrated problem. Specifically, there is close interaction between the formation of departments and layout of these departments. These problems are treated as separate problems that are solved sequentially. This procedure is mainly due to the complexity of each problem and the interrelationships between them. In this research, we take a first step toward integrating the flow-based department formation and departmental layout into comprehensive mathematical models and develop appropriate solution procedures. It is expected that these mathematical models and the solution procedures developed will generate more efficient manufacturing system designs, insights into the nature of the concurrent facility layout problem, and new research directions.
555

Analytical models to evaluate system performance measures for vehicle based material-handling systems under various dispatching policies

Lee, Moonsu 29 August 2005 (has links)
Queueing network-based approximation models were developed to evaluate the performance of fixed-route material-handling systems supporting a multiple workcenter manufacturing facility. In this research, we develop analytical models for fixed-route material-handling systems from two different perspectives: the workcenters?? point of view and the transporters?? point of view. The state-dependent nature of the transportation time is considered here for more accurate analytical approximation models for material-handling systems. Also, an analytical methodology is developed for analytical descriptions of the impact of several different vehicledispatching policies for material-handling systems. Two different types of vehicledispatching policies are considered. Those are workcenter-initiated vehicle dispatching rules and vehicle-initiated vehicle dispatching rules. For the workcenterinitiated vehicle dispatching rule, the Closest Transporter Allocation Rule (CTAR) was used to assign empty transporters to jobs needing to be moved between various workcenters. On the other hand, four different vehicle-initiated vehicle dispatching rules, Shortest Distance Dispatching Rule (SDR), Time Limit/Shortest DistanceDispatching Rule (TL/SDR), First-Come First-Serve Dispatching Rule (FCFSR), Longest Distance Dispatching Rule (LDR), are used to select job requests from workcenters when a transporter is available. From the models with a queue space limit of one at each workcenter and one transporter, two different types of extensions are considered. First, the queue space limit at each workcenter is increased from one to two while the number of transporters remains at one. Second, the number of transporters in the system is also increased from one to two while maintaining the queue space limit of one at each workcenter. Finally, using a simulation approach, we modified the Nearest Neighbor (NN) heuristic dispatching procedure for multi-load transporters proposed by Tanchoco and Co (1994) and tested for a fixed-route material-handling system. The effects of our modified NN and the original NN transporter dispatching procedures on the system performance measures, such as WIP or Cycle Time were investigated and we demonstrated that the modified NN heuristic dispatching procedure performs better than the original NN procedure in terms of these system performance measures.
556

Exploring project collaboration systems in the building industry

Laepple, Eberhard Sebastian 30 October 2006 (has links)
The use of Web-Based-Collaboration-Systems (WBCS) continues to grow as part of information technology development in the Architecture-Engineering-Construction (AEC) industry. WBCS provide different media channels to support collaboration across geographical distributed teams. However, many companies are still hesitant to integrate WBCS. This research provides an understanding of how WBCS are used in practice. Most distinctively, it obtained practice data from several major US architecture firms and examined about 30,000 transactions produced during actual design and planning projects as practicing architects, engineers and consultants used WBCS. The study investigated what information was used and exchanged among participants during the different design stages. This was related to the different media channels of WBCS. The raw project data has been coded and transformed into secondary data through computer-supported content analysis. Based upon categories from previous literature, such as communication, coordination and design theories, the data has been analyzed for sender, receiver, channel and content of information transmitted. The content has been characterized into work tasks, information handling behavior and design activities. Additional interviews with industry professionals produced information that had not been documented through WBCS and that corroborated the analytical findings. The combination of theory, quantitative, and qualitative analysis has been synthesized into a portrait of WBCS usage that was validated through triangulation. The analysis of digital records of design communication from practice through content analysis is a new research methodology in AEC. The evidence supporting design methods theory shows the changes in tasks and information handling in regards to the project phases. It indicates that the most frequent loops of design activity are Evaluation- Analysis-Synthesis and Evaluation-Synthesis-Evaluation. It documents the actual usage of WBCS based on descriptive statistics and Markov models. WBCS was used primarily as a document repository and calendaring tool. The remote team members used it more frequently than centrally located participants. The study shows the limitations of WBCS: none of the verbal communication was captured. More significant, the entire email exchange took place outside the WBCS. WBCS was used very extensively, if the implementation of the system supported the organizational structure and vice versa.
557

Packaging effects on logistics activities : A study at ROL International

Leek, Tobias, Hassel, Johan January 2006 (has links)
<p>Packaging has a major impact on the activities performed in a logistical value chain. Packaging can improve or decrease the efficiency of the outbound logistics process. It is therefore important to consider the activities and the value that they add to the overall process. ROL International is a Swedish store interior manufacturer that design, produce and distribute their products on a global basis. One of their basic products is the shelf concept. ROL wants to improve their efficiency and consider a change in the packaging method for the shelf concept. Two alternative packaging methods have been suggested and ROL want to know if either of the two alternatives would result in increased efficiency.</p><p>The purpose of this report is to evaluate the two packaging alternatives and their impact on the activities connected to the outbound logistics at ROL International.</p><p>Since the study was conducted at request from ROL International, it is considered as a qualitative single case study. Observations, mainly at ROL’s warehouse but also through an observation at one customer’s premises, were used for determination of the activities included throughout the studied process. In addition to the observations, interviews were conducted with key persons concerned with the effects of a change in packaging method. Secondary data in form of order and shelf statistics were important for the study due to its impact on the frequency in which the studied activities are performed.</p><p>The study found that neither of the two suggested packaging alternatives are suitable for implementation in the present situation. This is mainly because of the increase in activities needed to perform the packaging of shelves, which would result in increased cost that cannot be justified through enhanced customer service and higher quality. More-over, the study also found that the current process for picking customer orders are ineffi-cient and might require a restructuring of the warehouse operation in order to become more efficient.</p>
558

Internal material handling at Volvo Construction Equipment Braås

Saleh, Fatima, Bartsch, Susann, Steen, Jessica January 2008 (has links)
<p>Background: Material handling is a large part of a company´s internal work and represents between 15 % and 70 % of the total cost of a manufactured product. By improving the internal handling of material, more efficient distribution and manufacturing flows are possible. The material handling process is an input to the production and assembly process that has to be defined and mapped so that it can be improved. The material handling process studied at Volvo CE Braås includes goods receiving, storage, packaging as well as the order/delivery process to assembly, and will finish with the material transport to the assembly line.</p><p>Research questions: How can the material handling process, from goods receiving to assembly line, at Volvo CE in Braås be described by using VSM? What kinds of waste can be identified? By proposing a future-state map, how can the identified problems and waste be reduced or eliminated?</p><p>Methodology: This thesis is a descriptive case study and was conducted with a deductive approach. Data was collected by our own observations, personal interviews, statistics, benchmarking and questionnaire. The scientific credibility of this thesis was secured by for example using many sources, avoidance of assumptions, studying a common process and following standardized steps of the VSM tool.</p><p>Conclusions: The material handling process was described in the separated areas of goods receiving, storage and assembly line. Visualization was given in a current-state map. Five different kinds of waste were identified. Finally, suggestions of improvements were presented along with a future-state map.</p><p>Suggestions on future research: A more detailed VSM including information flow and lead times could be studied. Scenario simulations of critical areas within the material handling process could be preformed. Furthermore, an ABC classification of articles and storage locations can be done to optimize storage.</p>
559

Autonomer Brückenkran als automatisiertes Materialflusssystem /

Wecker, Thomas. January 1900 (has links)
Thesis--Universität Ulm, 2006. / Includes bibliographical references.
560

Quay crane scheduling at container terminals : reducing the maximum tardiness of vessel departures /

Wang, Lei. January 2003 (has links)
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references (leaves 40-42). Also available in electronic version. Access restricted to campus users.

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