cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.14457/cu.the.2015.174
title: Design of load frequency controller for power system subject to bounded persistent disturbances

description: The waveforms of the electric power generated from renewable energy sources such as wind and sunlight are known to be uncertain and, very often, vary persistently for a long period of time. This thesis presents the design of load frequency controllers for power systems that are subject to persistent disturbances by using the principle of inequalities and the principle of matching. The principal design objective is to guarantee that the magnitudes of the outputs of interest always stay strictly within their acceptable bounds for all time in the presence of all the possible disturbances. An advantage of the framework adopted here is that once a solution is found, the system is guaranteed to operate with satisfactory levels of security and quality supply. Two case studies have been carried out; the numerical results clearly show that the framework adopted here is suitable and effective, thereby giving a realistic formulation of the design problem.
DOI: 10.14457/cu.the.2015.175
title: Fundamental limits of the two-user gaussian x channel with limited receiver cooperation

description: Modern wireless communications via the X channel where each transmitter has an independent message for the corresponding receiver have become an active topic of research since they can support various services transmitted from sources to users or obtain different types of data transmitted from users to sources. However, interference is the important phenomenon that occurs unavoidably in these wireless communications and affects directly on the performance of the system. Cooperation is one of several methods that can mitigate the effect of interference and is considered in several communication scenarios. Unfortunately, the basic comprehension of the X channel with cooperation is somewhat less. In this dissertation, we study the two-user Gaussian X channel with limited receiver cooperation where both receivers exchange messages over the orthogonal receiver-cooperative links through the perspective of information theory that can be divided into 3 parts as follows: In the first part, we investigate the fundamental limits of the two-user Gaussian X channel with limited receiver cooperation using the Fano’s inequality, the data processing inequality, and the genie-aided techniques. The obtained result is called an outer bound. In the second part, we characterize the generalized degrees-of-freedom under the channel symmetric setting by using our proposed outer bound. The results in this part imply that the performance of our system can be improved when the amount of exchanged information between both receivers increases. However, the system reaches the saturation point of the receiver cooperation when the normalized capacity of the receiver-cooperative link \\kappa &gt;= 1/2, 1, 3/2 and 2 and 2 for the normalized interference level \\alpha \\in [0, 3/2], (3/2, 2], (2,5/2], and (5/2, 3] respectively. In the final part, we propose the strategies consisting of transmission scheme based on Han-Kobayashi strategy and cooperative protocol based on quantize-map-and-forward scheme and then give achievable rate regions based on the proposed strategies for both the general case and the strong Gaussian X channel type I case where SNR1 &gt; INR2 and SNR2 &gt; INR1. The obtained results show that our proposed strategy in the strong Gaussian X channel type I case achieves the capacity region to within 2 bits/s/Hz per message when \\beta and \\gamma in the common rate constraints at the transmitter are set such that most of the bounds in the achievable rate region reach theirs maximum value. This constant is independent of the channel parameters.
DOI: 10.14457/cu.the.2015.176
title: LED DIMMING TECHNIQUE THAT SUPPORTS VISUAL LIGHT COMMUNICATION

description: This research describes a design technique to control brightness of LED(Light Emitting Diode) light bulb that can be able to mix communication signal into visible light. This method is called Visual or Visible Light Communication (VLC) by put frequency in visible light and receives response back from receiver by Infrared. This method can be used for many various applications. In this research will test 3 applications, 1st Display message on LCD display via VLC for Electronics price tag, 2nd Application for Electronics Voting System and 3rd Application for temperature monitoring. Other feature is identically control brightness each LED light bulb for utility usage.
DOI: 10.14457/cu.the.2015.177
title: INTERFACIAL TENSION MEASUREMENT OF LIGHT OIL FROM FANG OILFIELD WITH ALKALINE-POLYMER SOLUTION

description: Enhanced oil recovery especially alkaline-polymer flooding is an important technique to improve oil recovery. It involves the injection of alkali to reduce the interfacial tension (IFT) between oil and water, and the injection of polymer to improve mobility ratio to produce more oil. In this study, the interfacial tension of light oil from Fang oilfield with alkaline-polymer solution will be measured and the effects of parameters such as pressure, temperature, salinity, types of solution and solution concentration on the interfacial tension are investigated. The results present that pressure has less effect on the interfacial tension because the experiment is in the liquid phase. For the effect of types of alkaline solution, strong base has higher performance in lowering the interfacial tension compared with weak base because strong base can completely dissociate in the solution so that the amount of ions are higher. This results in the higher amount of the in-situ surfactant and thus lowering more interfacial tension. Concentration of alkali plays a key role in the interfacial tension reduction accounting for 99.49%. Interfacial tension reduces with the increase of temperature for every type of the solution. Increasing polymer concentration tends to increase the interfacial tension. Salinity can increase the interfacial tension at low alkali concentration while decrease the interfacial tension at high alkali concentration. Divalent ions have low impact on the interfacial tension. The results can be used as the fundamental data for future studies such as the core flooding test and simulation for enhanced oil recovery.
DOI: 10.14457/cu.the.2015.178
title: EFFECTIVE MIX DESIGN OF HEAVYWEIGHT CONCRETE FOR GAMMA-RAY SHIELDING AND MECHANICAL PROPERTIES OF CONCRETE

description: Utilization of heavyweight concrete as radiation shielding has bringing benefits not only in energy for nuclear power plant, but also accelerators in medical and in industrial, then in radiation sources for agricultural field. The lack of experiment related to structural member in heavyweight concrete is a reason in performing this study. Concrete that were resulted for this study restricted to barite (BaSO4) as heavy material that highly available in Thailand. Modification experiment was expected to achieve effective barite concrete mixture using local material from Thailand. This experiment will evaluate mechanical properties of barite concrete, attenuation of gamma-ray, and barite reinforced concrete beam as parameter to determine the effectiveness of the mixture. 20 different barite concrete mixtures with 2 variations of w/c ratios and 4 classifications of replacement percentage aggregate will be examined. Using Cesium-137 and Cobalt-60 energy sources, linear attenuation coefficient (µ) of barite concrete will be measured at two different energies which are 0.662 MeV and average 1.250 MeV (combination 1.173 MeV and 1.332 MeV), respectively. We concluded that replacement coarse aggregate with normal aggregate deemed most advantageous in term of workability of concrete. In relation with provision standard, ACI 349-06 equation is not applied for barite concrete due to underestimated. Contribution replacement normal sand in mixture is affected in stiffness of the beam. Moreover, percentage barite in the mixture had main role in ductility factor and not correlated with number of w/c ratio and type of replacement aggregate in the mixture.
DOI: 10.14457/cu.the.2015.179
title: THE IMPROVEMENT OF FIXED AMBIGUITY RESOLUTION RATE IN GPS KINEMATIC POSITIONING MODE USING GENETIC ALGORITHMS

description: The two key factors in achieving high-precision positioning results from GPS carrier phase observations are the data differencing technique and the ambiguity resolution process. A double differencing technique has been widely used to reduce biases in GPS observations. However, un-modeled biases can persist, and these reduce the number of ambiguity-fixed solutions, especially in GPS kinematic positioning mode. Therefore, noisy or unwanted GPS satellites must be identified and removed from the data processing step. This requires users to edit or filter noisy data in the processing step. Data filtering is essentially a trial-and-error process, with users reprocessing the data until satisfactory ambiguity-fixed solutions are obtained. Often, data filtering is a time-consuming process that requires the skills of an experienced user. In this research, a genetic algorithm (GA) was developed to overcome the aforementioned problem. This GA is used to optimize the selection of GPS satellites in order to improve the number of ambiguity-fixed solutions in GPS kinematic positioning mode. Experimental results demonstrate that the GA can enhance the number of ambiguity-fixed solutions without user-assistance in the data processing step. However, the experiment did not use practical kinematic data. Therefore, further investigations were conducted to improve the ability of the GA. The sliding windows technique was integrated with the GA to enhance the number of ambiguity-fixed solutions by varying the finite-length selection windows in the data processing step. This new proposed methodology was tested with raw GPS kinematic observation data from a practical mobile-mapping system. The results indicate that the proposed method produces considerably more ambiguity-fixed solutions than either the GA alone or the standard GPS kinematic post-processing. The experimental results clearly demonstrate that the proposed methods can be used to improve the ambiguity-fixed solutions in GPS kinematic positioning mode without the need for user-assistance in the data processing step.
DOI: 10.14457/cu.the.2015.180
title: CASE STUDY ON PHYSICAL SECURITY ASSESSMENT OF A CATEGORY 1 GAMMA IRRADIATION FACILITY

description: Analysis and evaluation of a physical protection system (PPS) design begin with a review and thorough understanding of the protection objectives of the system. A physical protection system is deployed to prevent or mitigate loss of valuable assets (e.g., property or life). It consists of three important elements: detection, delay, and response. In our study, the asset is the Category I radioactive sources, which have high activity and need to have high security system to secure them. In Thailand, the Category 1 source facility is required to have effective PPS to protect people and environment from radiological hazards. This study focuses on the evaluation of a physical protection system of a Category 1 gamma source facility in Thailand against several potential cases of outsider intrusion, using the EASY model to calculate the probability of interruption (PI). The study includes 4 parts: collect data to determine system objectives, evaluate the collected data for the current design, design additional PPS, and analyze result and recommendation. Based on the current PPS design and the design basis threat data, there are 6 potential attack scenarios to evaluate the PPS against. Each consists of three modes of transportation potentially used by the adversary: running, motorcycle, truck. The result shows that the PI in several scenarios is in the range of 0.50-0.75, which is considered “too low” and something should be done to improve the PPS. After improving the PPS by installing a steel cage at the laboratory room door to increase delay, the PI for all scenarios is increased to above 0.90, meaning that the security system effectiveness is high.
DOI: 10.14457/cu.the.2015.181
title: A deterministic algorithm for global Maximum power point calculation of a solar farm

description: Optimizing the e_ciency plays a very important role in harvesting solar energy by PV systems. This dissertation proposes a few methods which estimate all local maximum power points (MPP) and the global maximum power point of a PV system in short time. They require only a few online measured values. PV systems may be driven directly to global MPP without power searching. Consequently, the time for tracking is reduced, the efficiency of PV systems is, hence, increased. In this dissertation, the solar cell is represented by the single diode model. The relation of voltage and current at (MPPs) is exploited and this di_erentiates the proposed method from the others. Solar cell parameters for the model are not provided by solar cell panel manufacturers. So parameter extraction is a requirement. A new simple method which uses only given data in product datasheet but yields high accurate results is also proposed. Some experiments and simulations evaluate the correctness, robustness and reliability of the proposed techniques. The results obtained are compared with those of other referenced methods. Two programs are written basing on the proposed algorithms. First one is for solar cell parameters extraction using only information in product datasheet. The second is used for simulation and calculation the MPPs of the PV system which may be configured exibly by the users.
DOI: 10.14457/cu.the.2015.183
title: Opportunistic Hybrid Network Coding (OHNC) method and QOS metrics modeling for Smart Grid Wireless Neighborhood Area Networks

description: Designing a useful data collection scheme in Smart Grid Neighborhood Area Network (Smart Grid NAN), which is the most critical part in Smart Grid communication, has drawn wide attention of researchers in recent years. However, there are few studies in data gathering method to fulfill the strict requirements of Smart Grid services. In this dissertation, we first propose an innovative Quality of Service (QoS) model for wireless network in Neighborhood Area Network based on exploring the nature features of Smart Grid applications. We have chosen reliability and latency requirements as the most important criteria and implemented the S-shaped curve model for performance evaluations of any candidate communication schemes. Comparing with other existing QoS models, our model is easy to use and help to reduce the time and cost. We then suggest Opportunistic Hybrid Network Coding (OHNC) method for data gathering in wireless Smart Grid NAN context. Network Coding has been proved reliable and latency-beneficial, especially in wireless environment. Based on simulation, the OHNC shows that Network Coding method can fulfill the QoS requirements of current and upcoming Smart Grid applications.
DOI: 10.14457/cu.the.2015.184
title: INVESTIGATION OF AN EFFICIENT PETROLEUM FISCAL REGIME FOR THAILAND

description: The paper investigates the current fiscal regime, utilizing in Thailand (both Thailand-I and Thailand-III), under the condition of typical production profile and cost structure of petroleum production in Thailand. The analysis is based on various sizes of the actual operating oil and gas fields in Thailand from the past. The efficiency of the fiscal regime is the objective of the sharing benefit between the host government and the oil company, which creates the win-win situation, thus, prevents the future renegotiation among the parties. The analysis performs by the discounted cash flow model as a base case model to estimate the government take and company take. The results are compared with neighboring countries such as Malaysia and Myanmar. Monte Carlo simulation is also used to verify the result under the distribution of various inputs to get the distribution of the company take. The result shows that Thailand-I tends to be regressive in most cases, concerning its regressive tool like fixed-rate royalty. Though, Thailand-III gives a good response to wider changing conditions but still has a regression in some cases such as long production fields or costly fields. Moreover, the modification of fiscal regime is examined under the concession externsion in this study. By adjusting the advantageous and detrimental elements in Thailand-III, the progressivity is observed with the proper gain to the government.
DOI: 10.14457/cu.the.2015.185
title: DEVELOPMENT AN ONLINE RADIOACTIVE SOURCE SECURITY SYSTEM

description: An online radioactive sources security System (ORSS) was developed for preventing high activity radioactive sources from committing a malicious act, since the radioactive source could be used to build a Radiological Disposal Device (RDD). The design features of an ORSS system in this research was covered the basic security functions such as detection, deterrence, delay, response, and security management according to the security level A of IAEA guideline. A detector was operate as an economical radiation monitor and integrated with the subsystem of compact CCTV unit, motion sensing unit, door access unit, and GPS tracking unit in order to link all alarm signals through a computerizing system in sequential actions. The system control software was also developed. The alarm signal could be sent via both internet and SMS mobile phone to the security center and responsible persons with online monitoring access. In functional tested results, it was revealed that the developed system could prevent unauthorized person from accessing the secured source in multiple alarm layers operation and could be used for protecting a high activity radioactive source removal without authorization at working place such as hospitals, industries and laboratories with high reliability security.
DOI: 10.14457/cu.the.2015.186
title: Modeling and Effect Analysis of Tilt and Azimuth Angles for Rooftop Photovoltaic Arrays

description: Electricity is so important that we use it in various fields of human activity every day. Indeed, we cannot even dream of living in absence of electricity in modern times and the use of electricity is increasing day by day. Global solar radiation has the potential to meet all of our energy requirements and the recent installation growth rates in the PV sector have demonstrated the potential benefit. One of the most important parameters that affects Photovoltaic (PV) panel system is solar radiation received from the Sun. Because both position and angle of a PV panel are important factors in PV system design, they are considered in many numerical analyses in this thesis. Investigation the optimal tilt angle of PV panels in this thesis uses a mathematical method, the forecasted solar radiation in different tiled and azimuth angles, and the satellite data of monthly average daily solar radiation and diffuse solar radiation on horizontal surface of 10 years. Using monthly average daily optimal tilt angle can increase the received energy than using the optimal yearly tilt angle. However, for rooftop installations, the module mounting system selected is dependent on the roof type and the structural characteristics of the building. Sun tracking systems are also possible, but these are more common in the ground mounted installations. They are typically more expensive and technically complicated and require additional maintenance.
DOI: 10.14457/cu.the.2015.187
title: Adaptive error-resilient techniques for H.265/HEVC video transmission

description: High efficiency video coding (HEVC) is the latest video coding standard that enables the transmission of high resolution videos over wireless networks. In this dissertation, HEVC based error resilient video coding is proposed to target real time video transmission applications. A feedback-based reference picture selection (RPS) method called hierarchical-P RPS is proposed such that it can adapt with the HEVC coding framework. Due to hierarchical coding structure of HEVC, the quality of each frame in the sequence varies depending on its location in the hierarchical structure. High quality pictures are used as reference for several subsequent pictures while low quality pictures are used for only one consecutive picture. When error is detected, hierarchical-P RPS algorithm will select suitable reference pictures subject to the trade-off of low quality picture with short temporal distance and high quality picture with long temporal distance. To enhance the performance of the proposed RPS, we combine feedback-based RPS and region-of-interest (ROI) based intra refresh method by using some novel features of HEVC. Each block in the ROI region is encoded with intra mode according to error status such that it can enhance the quality of picture in ROI area and can avoid the motion search process in this area. To enable block level intra refresh, rate control is also modified to fit in the framework. Experimental results demonstrate that the proposed framework can achieve better subjective and objective quality, compared to the hierarchical-P RPS algorithm. The average PSNR improvement of proposed algorithm over modified RPS algorithm is 1.04 dB and that over HEVC reference software with regular intra frame refresh is about 5.23 dB.
DOI: 10.14457/cu.the.2015.188
title: EVALUATION OF TOE-TO-HEEL AIR INJECTION (THAI) COMBINED WITH WET COMBUSTION

description: Heavy oil cannot be easily produced by means of conventional oil recovery methods due to its extremely high viscosity. However, by utilizing a suitable Enhanced Oil Recovery (EOR) technique, heavy oil can be produced. In-situ Combustion (ISC) with modification of well configuration called Toe-to-heel Air Injection (THAI) is one of the solutions. The technique is performed by injecting air from horizontal or vertical well to create fire front and producing heated oil from horizontal wells. Further modification of THAI is performed by co-injecting water with air to generate in-situ steam to recover heat in burnt zone. In this study, combination of THAI and wet combustion is performed and parameters affecting oil recovery are studied. From the results, it is found that oxygen content is very important design parameter for in-situ combustion. As fire front must be generated, enrichment of oxygen is required and increasing oxygen through increment of oxygen concentration is more efficient than increase of air injection rate. For properties related to wet combustion, time to start injecting water plays more important role for wet combustion compared to amount of water injected as the early time to start wet combustion can speed up distribution of heat of combustion to entire reservoir. Moreover, optimal air injection rate that is obtained from dry combustion can be slightly increased in case of wet combustion as co-injection of water helps retarding air flow ability. So that chance of burning at production well is extended. Injecting air from vertical well obtained benefit from higher amount of air injected compared to horizontal well injector as reservoir pressure is low in shallow depth. By using the best conditions for wet combustion, oil recovery of about 55% is achieved which is higher than dry combustion case of about 17 %. From an increase of heat capacity and a reduction of heat conductivity, effect of thermal conductivity is more pronounced than heat capacity and high value of thermal conductivity is preferable for this combined technique. Lower irreducible water saturation is favorable as it would provide benefit in steam propagation. Good vertical permeability is desirable as it increases amount of air injected which consecutively speeds up time to create fire front. During the combustion process, combustion may appear at production well when operating parameters are improper or can be from uncertainty of reservoir parameters such as low and high irreducible water saturation, low vertical permeability and high value of heat capacity and this situation is extremely dangerous and must be avoided.