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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.
41

A Study Of Brightwater Injection Efficiency On Sector Model Using Stars Software

Pashayev, Nariman 01 September 2011 (has links) (PDF)
Maintaining proper waterflood conformance is a critical component of waterflood management. Most methods used to control waterflood conformance have proven to be only marginally effective. A unique technique has been developed for creating a durable reservoir flow restriction that diverts injected water into unswept reservoir sections. Placement of the restriction is based in the location of the thermal front between the injector and producers. A thermally activated nano-sized particle system-BRIGHTWATER - was developed that gives us this restriction. A sector model of ACG field has been developed to study applicability of BRIGHTWATER injection in ACG field. A decrease in oil production and increase in water production were seen in wells after production started. The water cuts were high for South flank wells. From the simulation it was seen that there were unswept zones. So this new technology was decided to apply in this thesis work. Several runs were conducted to study effect of BRIGHTWATER concentration, crosslinker concentration, injection rate and pressure, injection temperature, injection times and injection well locations. Results are given in tables and figures and briefly discussed. Also the best and the worst cases are chosen from the results, and analyzed in detail. Finally, economical analysis is given. It has been observed that injecting the polymer in slug form is better than continuous injection. Injecting polymer in early times may give better results. Injection of polymer with 3 slug sizes between 6 month injection periods seems more beneficial. According to the simulation results optimum polymer injection temperature was 780 F. Good results were obtained when polymer was injected at 65000, 75000 and 85000 bbl/day injection rates. Oil recoveries obtained during simulation were in the range of 1.4% to 3.8 % which gives additional recovery of 11 to 31 MMSTB of oil. BRIGHTWATER injection has been found to be applicable to ACG field.
42

Controller Design And Simulation For A Helicopter During Target Engagement

Avcioglu, Sevil 01 December 2011 (has links) (PDF)
The aim of this thesis is to design a controller for an unmanned helicopter to perform target engagement. This mission is briefly defined as / the helicopter flies to a firing point under the commands of a trajectory controller, and then it is aligned to the target with attitude control. After weapon firing, the helicopter initiates a return maneuver under again the commands of the trajectory controller. This mission where the continuous systems and discrete guidance decisions are to be executed in coherence can be studied as a hybrid control problem. One hybrid control approach which is used in this study is the representation based on two motion primitives: trim trajectories and maneuvers. To obtain the desired trim trajectories and the maneuvers, a dynamic inversion based controller is developed. The controller has two loops: the inner loop which controls the helicopter attitudes and the outer loop which controls the helicopter trajectory. A guidance algorithm is developed which enables the controller to switch from the inner loop to the outer loop or vice versa. Simulations are generated to test the controller performance.
43

Prototype Development And Verification For An Ip Lookup Engine On Fpgas Performance Study

Ozkaner, Akin 01 February 2012 (has links) (PDF)
The increasing use of the internet demands more powerful routers with higher speed, less power consumption and less physical space occupation. IP lookup operation is one of the major concerns in today&rsquo / s routers for providing such attributes. To accomplish IP lookup on routers, hardware or software based solutions can be used. In this thesis, an SRAM based pipelined architecture proposed earlier for ASIC implementation is re-designed and implemented on an FPGA in the form of a BRAM based pipelined 8x8 torus architecture using Xilinx ISE and simulated and verified using Modelsim Simulator. Some necessary modifications and improvements for FPGA implementation are carried out. The results of our experiments, which are performed for a real router lookup table and a real time traffic load with various optimizations, are also presented. Our study and design effort demonstrates the feasibility of the FPGA implementation of the proposed technique, of course with a considerable performance penalty.
44

SELECTION AND PSYCHOSOCAL PREDICTORS OF WELLBEING: A STUDY AMONG FOTBALL ACADEMY PLAYERS / Selektion och faktorer som kan predicera välmående: En studie kring akademispelare i fotboll

Lilja, Henric January 2011 (has links)
The objectives were to study: (1) if psychosocial factors (such as social support from coaches and peers), within a football context, could predict psychological well-being among soccer academy players (2) the relationship between selection and well-being among football academy players and (3) compare the age categories 11-14 and 15-19 in perceived wellbeing, experiences of selection and social support from coaches and peers.  In total, 443 players from four academy settings participated in the study. The player’s ages differences were between 11-19 years. The instrument used was the Swedish health survey developed by the Swedish Health Institute with a number of football specific items added. Result suggests a regression model including two variables (social support from coaches and peers) explaining 16, 6 % of the psychological well-being. Further, a negative relationship was found between selection and perceived well-being. Another finding was that the youth players (11-15 years) experienced higher levels of social support and psychological well-being, but experienced selection more negatively compared to junior players (15-19 years). Recommendations are given to coaches to be aware of developing a supportive coaching style. Another recommendation to increase well-being is to develop support mechanisms to help the youth players in academy settings to cope with the pressure of selection. The results are discussed in relation to theoretical frameworks and previous research.  Keywords: Football academies, psychological well-being, social support and selection / Svenska fotbollsförbundet
45

Evolutionary optimisation for Volt-VAR power quality control

Boyi Bukata, Bala January 2013 (has links)
With the more environmentally friendly smart grid initiatives during the past few years, intelligent operation and optimisation of the electricity distribution system have received an increasing attention in power system research worldwide. Power flow from the distribution substation to the customer can be optimised at Volt-Ampere-Reactive (VAR) level by reducing the reactive power. Distributed Generation (DG) and Renewable Energy Sources (RES) represent both the broadest potentials and the broadest challenges for intelligent distribution systems and smart grid control. In general, the flexibility envisaged by integrating RES during smart grid transformation is often surrounded by nonlinearities such as wave-form deformations caused by harmonic currents or voltages, which impliedly increase control system complexity. Therefore, conventional controllers presently implemented need to be re-engineered in order to solve power quality (PQ) problems therein. This work aims to improve the controllability of Distribution Static Compensators (DSTATCOMs) through the development of improved control systems using evolu- tionary computation enabled design automation and optimisation. The resultant Volt-VAR Control (VVC) optimises PQ in the presence of nonlinearities and uncertainties. It also aims at increasing overall system’s sensitivity to unconsidered parameters in the design stage like measurement noise, unmodelled dynamics and disturbances. This is otherwise known as the robustness of the system offering it with valuable potential for future smart grids control, which are anticipated to present more nonlinearities due to virtual power plant (VPP) configuration. According to European Project FENIX, a Virtual Power Plant (VPP) aggregates the capacity of many diverse Distributed Energy Resources (DER), it creates a single operating profile from a composite of the parameters characterizing each DER and can incorporate the impact of the network on aggregate DER output. To particularly solve PQ problems, two objectives are realised in this thesis. First, a non-deterministic evolutionary algorithm (EA) is adopted to generate optimum fuzzy logic controllers for DSTATCOMs. This design methodology extends the traditional computer-aided-design (CAD) to computer-automated-design (CAutoD), which provides a unified solution to diverse PQ problems automatically and efficiently. While realizing this objective, the prediction ability of the derivative term in a proportional and derivative (PD) controller is improved by placing a rerouted derivative filter in the feedback path to tame ensuing oscillations. This method is then replicated in a fuzzy PD scheme and is automated through the capability of a “generational” tuning using evolutionary algorithm. Fuzzy logic controllers (FLCs) are rule-based systems which are designed around a fuzzy rule base (RB) related through an inference engine by means of fuzzy implication and compositional procedures. RBs are normally formulated in linguistic terms, in the form of if ... then rules which can be driven through various techniques. Fundamentally, the correct choice of the membership functions of the linguistic set defines the performance of an FLC. In this context, a three rule-base fuzzy mapping using Macvicar-Whelan matrix has been incorporated in this scheme to reduce the computational cost, and to avoid firing of redundant rules. The EA-Fuzzy strategy is proven to overcome the limitation of conventional optimisation which may be trapped in local minima, as the optimisation problem is often multi-modal. The second objective of the thesis is the development of a novel advanced model-free predictive control (MFPC) system for DSTATCOMs through a deterministic non-gradient algorithm. The new method uses its “look-ahead” feature to predict and propose solutions to anticipated power quality problems before they occur. A describing function augmented DSTATCOM regime is so arranged in a closed-loop fashion to locate limit cycles for settling the systems nonlinearities in a model-free zone. Predictive control is performed upon the online generated input-output data-set through the power of a non-gradient simplex algorithm. The strategy is to boycott the usage of a system model which is often based on gradient information and may thus be trapped in a local optimum or hindered by noisy data. As a model-free technique, the resultant system offers the advantage of reduction in system modelling or identification, which is often inaccurate, and also in computational load, since it operates directly on raw data from a direct online procession while at the same time dealing with a partially known system normally encountered in a practical industrial problem. Steady-state and dynamic simulations of both control and simulation models in Matlab/Simulink environment demonstrate the superiority of the new model-free approach over the traditional trial-and-error based methods. The method has been varified to offer faster response speed and shorter settling time at zero overshoot when compared to existing methods. A SimPowerSystems software simulation model is also developed to check experimental validity of the designs. Where specific PQ problems such as harmonics distortion, voltage swells, voltage sags and flicker are solved. A noticeable record level of THD reduction to 0.04% and 0.05% has respectively been achieved. It is therefore safe to recommend to the industry the implementation of this model-free predictive control scheme at the distribution level. As the distribution system metamorphoses into decen- tralised smart grid featuring connectivity of virtual power plants mostly through power electronic converters, e.g., DSTATCOM, it stands to benefit from the full Volt-VAR automated controllability of the MFPCs low control rate. Based on CAutoD, the practical implementation of this technique is made possible through digital prototyping within the real-time workshop to automatically generate C or C++ codes from Simulink, which executes continuous and discrete time models directly on a vast range of computer applications. Its overall wired closed-loop structure with the DSTATCOM would offer reliable and competitive advantages over its PID and SVC (CAD-based) counterparts currently being implemented through physical prototyping, in terms of; quick product-to-market pace, reduced hardwire size, small footprint, maintenance free as it is model-free (and automated), where pickling the controller timers and model contingencies are unnecessary as would be with the conventional controllers. More importantly, the scheme performs the aforementioned control functions robustly at a high speed in the range of 0.005 → 0.01 seconds. High enough to capture and deal with any ensuing PQ problem emanating from changes in customer’s load and system disturbances in an environmentally friendly, but less grid-friendly renewable generators.
46

Vi är skolan : En undersökning av samarbetet mellan svenska NIU fotbollsgymnasium och fotbollsakademier

Anello, David, Rasmus, Hallbäck January 2014 (has links)
Background: There is a newly founded national sports education program. This newly founded national sports program comprises of several different sports of which football is one of them. Before a football player can reach the European- or national elite the player usually is first developed in clubs and their respective academies where a lot of time is spent on fine tuning the players’ individual skillsets. The main goal for the NIU program is to develop future elite athletes to different sports. When it comes to football, the Swedish Football Association and the Swedish school board have together developed a study plan which will serve as a guideline for the NIU-football classes in Sweden. Because of this, it is interesting to get a further insight in the training setup of the youth academies and the involved upper secondary schools. Purpose: The purpose of this thesis is to examine football schools and their cooperation with football academies. The purpose is also to examine the potential goals that the different schools have with the academies. Methodology: This thesis has a qualitative approach with the authors gathering data with the help of interviews with members of the respective schools and football academies. A document study has also been done in order to further strengthen the empiric data. Result: The cooperation between school and academy is incredibly thorough. The academies are in charge of the NIU training-sessions and decide what to train according to their own preferences and goals but stay within the schoolboards theoretic guidelines.
47

External Control Of Puma 700 Series Robot Based On The Communication Protocols Lun And Ddcmp

Gebizlioglu, Onder Emin 01 December 2003 (has links) (PDF)
This thesis analyzes the supervisory control of the PUMA 700 series robot through a remote computer. Supervisory communication carries the control through MARK II controller, common controller for the PUMA robots, to a standard PC, enabling the development of purpose specific control programming without the knowledge of the VAL (Variable Assembly Language), robot-programming language. Using the supervisory communication feature of PUMA, new control software has been developed in which both VAL commands and interactive control commands can be executed simultaneously. The supervisory communication with the control software enables exploitation of third party applications and additional operating system features. The supervisory communication uses the Digital Data Communications Message Protocol (DDCMP). The frame structure of data messages, which is specific to PUMA robots, is fitted into this protocol. The messages embedded into DCMP are actually logical units, having different abilities and features. Data messages are formed with the interactive control software according to execution requests of the user. This thesis explains the implementation of the communication without using the CRC (Cyclic Redundancy Checking) on the remote computer side and the data messages formed with the interactive control software, which also enables the use of sensory inputs (camera, infrared, sound, color information) to be used for the robot motion control.
48

Deriving Strategies And Developing Balanced Scorecard For General Directorate Of Environmental Impact Assessment And Planning In Ministry Of Environment And Forestry.

Ozcan, Mehmet 01 December 2003 (has links) (PDF)
In this study, it is aimed to derive strategies and develop a Balanced Scorecard in General Directorate of Environmental Impact Assessment and Planning in Ministry of Environment and Forestry. Firstly, the objectives of the General Directorate defined in the law are reassessed and strategies to realize the objectives are derived by making use of feedback received by conducting surveys to 4 main stakeholder groups which are the staff of the General Directorate, Provincial Directorates, companies preparing EIA reports, other public institutions, and interviews with managers. Following the determination of strategies, performance measures for each strategy are specified, replaced into internal business perspective, stakeholder perspective and learning and growth perspective in the Balanced Scorecard and and finally deployed to head of departments and branch offices.
49

A New Route To The Synthesis Of Nanocomposites By Using An Unsaturated Polyester Matrix

Toprak, Pelin 01 September 2004 (has links) (PDF)
This study was conducted to investigate the effects of organoclay type and concentration on the nanocomposites synthesized by &ldquo / In-Situ Polymerization&rdquo / and &ldquo / Prepolymerization&rdquo / methods. In-Situ Polymerization Method was in fact a new route which consisted of dispersing the monomers / propylene glycol, maleic anhydride and o-phthalic anhydride into the galleries of montmorillonite followed by subsequent polymerization. The Prepolymerization Method involved the addition of montmorillonite to the previously synthesized unsaturated polyester. As the first step, all the compositions were prepared by Cloisite 30B, and then for comparison of clay type, nanocomposites containing 3 wt.% of Cloisite 15A and Cloisite 25A were also synthesized. The efficiency of the two methods were compared with regards to their structural, thermal and mechanical properties. According to the results of XRD analysis, in both methods, maximum intercalation was observed when Cloisite 30B was used. An exfoliated structure was obtained in the Prepolymerization Method at 3 wt. % Cloisite 30B content. In all clay types, the increase in the d-spacings of the organoclays was higher when the Prepolymerization Method was applied. With Cloisite 30B, maximum improvement in the impact strength was obtained at 3 wt. % organoclay loading and the In-Situ Method yielded better results leading to a 77% increase in the impact strength at this organoclay loading. Among the organoclay types, Cloisite 15A was found to give rise to maximum increase in the impact strength. With the Prepolymerization Method higher improvement in flexural strength and flexural modulus was obtained owing to the lower styrene content in the crosslinking medium. The elongation at break values followed a decreasing trend with increasing clay content but did not show any significant difference when the clay types were compared.
50

Characterization Of Kizilcahamam Geothermal Field By Tracer Testing

Kaya, Tevfik 01 September 2005 (has links) (PDF)
ABSTRACT CHARACTERIZATION OF KIZILCAHAMAM GEOTHERMAL FIELD BY TRACER TESTING Tevfik Kaya M.S, Petroleum and Natural Gas Engineering Department Supervisor : Assoc. Prof. Dr. Serhat Akin Co-Supervisor : Prof. Dr. Mahmut Parlaktuna September 2005, 107 Pages Kizilcahamam Geothermal Field which is 70 km far from Ankara, has been utilized for Geothermal District Heating System, 25 MWt, 2500 residences capacity, greenhouses heating, thermal facilities since 1994. The average production rate is 350m3/h during the heating season , 150m3/h during the summer season for hot water and yearly average reinjection rate is 114m3/h from the field. The long term projections has been studied concerning on expected pressure decline by matching 10 years field history data which contain dynamic level and temperature data. The pressure decline is 140 kPa in the field between 1999 and 2005 with the existing reinjection rate, if the existing rates do not change, the additional pressure decline which is 120 kPa will be occurred up to 2011. In order to get more information from the field, the fluorescein as tracer has been injected in to the MTA-1, and the samples were collected from the MTA-2, Fethi Bey, IHL-1 and IHL-3 for 3 months. The fluorescein concentration has been detected by using fluorimeter, and tracer concentration time plots were analyzed. The fluoreiscein was detected in short breakthrough time in MTA-2 and Fethi Bey which are close to reinjection well, breakthrough time is longer in IHL-1 and IHL-3. The interpretation of tracer test shows that there is communication between all wells. Tracer concentration time plots were compared with different mathematical models, the best match was obtained with multi-fractured model. These results show that Kizilcahamam field is not homogeneous field. It is expected that increasing the reinjection rate will decrease the pressure decline in the field.

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