Approved for public release; distribution is unlimited / Observations of the temporal evolution of ripples are analyzed in terms of geometry, migration, crest orientation, and their predicted geometry by models using wave orbital velocities. Two weeks of bedform data were obtained in the surf zone during the RIPEX/SBE in April, 2001. Bed sediment consists of medium- to coarse-grained sand (D50=0.43mm). Models capture temporal trends in ripple geometry, but regression analyses show that they do not handle the range in forcing characteristics and geometries in the surf zone well. Transport models of bedload and total load formulated under uni-directional flows qualitatively capture the temporal evolution of observed transport by ripples, suggesting that under low to moderate forcing, bed load and suspended load occur mostly within the bed-following bottom boundary layer, andare measurable by ripple migration alone. Models predict large transport rates when flat beds were observed, so that at higher forcing ripples cannot be used to measure total sediment transport. Using a two-dimensional probability density function (PDF) of vector displacement peaks, a new ripple analysis model is proposed, incorporating a hierarchy of forcing complexity that includes such physical processes as directional spreading, axis rotation, orbital asymmetry, superimposed currents and infragravity wave velocities. The two-dimensional PDF's are compared with concurrent three-dimensional bed maps and are found to assist in describing ripple sizes, types, orientations, and migration velocities. / Lieutenant, United States Navy

Master of Science / Department of Electrical and Computer Engineering / Anil Pahwa / Understanding electricity consumer behavior at different times of the year and throughout the day is very import for utilities. Though electricity consumers pay a fixed predetermined amount of money for using electric energy, the market wholesale prices vary hourly during the day. This analysis is intended to see overall behavior of consumers in different seasons of the year and compare them with the market wholesale prices. Specifically, coincidence of peaks in the loads with peak of market wholesale price is analyzed. This analysis used data from 101 homes in Austin, TX, which are gathered and stored by Pecan Street Inc. These data were used to first determine the average seasonal load profiles of all houses. Secondly, the houses were categorized into three clusters based on similarities in the load profiles using k-means clustering method. Finally, the average seasonal profiles of each cluster with the wholesale market prices which was taken from Electric Reliability Council of Texas (ERCOT) were compared. The data obtained for the houses were in 15-min intervals so they were first changed to average hourly profiles. All the data were then used to determine average seasonal profiles for each house in each season (winter, spring, summer and fall). We decided to set three levels of clusters). All houses were then categorized into one of these three clusters using k-means clustering. Similarly electricity prices taken from ERCOT, which were also on 15-min basis, were changed to hourly averages and then to seasonal averages. Through clustering analysis we found that a low percent of the consumers did not change their pattern of electricity usage while the majority of the users changed their electricity usage pattern once from one season to another. This change in usage patterns mostly depends on level of income, type of heating and cooling systems used, and other electric appliances used. Comparing the ERCOT prices with the average seasonal electricity profiles of each cluster we found that winter and spring seasons are critical for utilities and the ERCOT price peaks in the morning while the peak loads occur in the evening. In summer and fall, on the other hand, ERCOT price and load demand peak at almost the same time with one or two hour difference. This analysis can help utilities and other authorities make better electricity usage policies so they could shift some of the load from the time of peak to other times.

Background: A novel, isothermal nucleic acid amplification method, RT-LAMP, presents potential for nucleic acid amplification-based diagnostics in resource-limited settings. Low-cost HIV-1 viral load monitoring will improve access to ART for HIV-1-infected individuals present in settings where on-site viral load testing is unavailable. Aim: The aim of this dissertation was to develop an RT-LAMP HIV-1 viral load assay by combining the RT-LAMP reaction with colorimetric amplification detection by hydroxy-naphthol blue dye. Methods: Different approaches for HIV RNA extraction from patient plasma and culture supernatant were studied to obtain template for RT-LAMP. Reaction products for 4 different RT-LAMP primer sets were analysed using agarose gel electrophoresis and restriction digestion. Results: The first 3 primers sets produced persistent off-target amplification. The fourth primer set, designed against culture supernatant DU179, produced a target-specific colour change from violet to blue after 1 hour, following optimisation of amounts of Mg2SO4 and AMV RT. Further studies showed HNB detection sensitivity to template copy number. Conclusions: Initial reaction conditions pertaining to an RT-LAMP based, colorimetric HIV-1 viral load assay were established. Further work is required to determine the reaction duration at which the colour change represents a viral load of ≥1000 copies HIV RNA per ml plasma.

In power system studies, some parameters cannot be measured directly by using the currently existing power meters. These power system parameters include the power system Thevenin impedance, harmonic impedances, zero sequence impedance, and the load model parameters. The power systems Thevenin impedance at a load bus is an important parameter for power system planning and operation. The effects of changing the system operation conditions on voltages at the load buses can be easily determined if the power system impedance parameters are known. Moreover, by knowing the Thevenin equivalent parameters, one can calculate the systems voltage stability margin and maximum loadability. The knowledge of power system harmonic impedances is necessary for harmonic mitigation, determination of harmonic limit compliance, prediction of system resonance, and harmonic propagation studies. Moreover, real-time monitoring of the systems harmonic impedances provides significant improvements to the design and operation of active filters. The systems zero sequence impedance at the substation bus is also important information for power system studies. It is used to calculate the different ground fault levels at substations. Furthermore, the loads in power systems play a significant role in power system planning, control, and stability analysis. Having reliable and accurate models of the loads is essential for designing automatic control systems and optimizing their configuration. Obtaining such models has been a challenging problem for power system engineers for decades, especially in the current deregulated market environment. This thesis presents newly developed and verified algorithms for online measurement and monitoring of these power system parameters. The algorithm proposed for monitoring the systems Thevenin, harmonic, and zero sequence impedance parameters, uses the natural variations of the loads connected to the substations. The proposed algorithm for monitoring of load model parameters uses the voltage and current waveforms captured during the operation of the Under Load Tap Change (ULTC) transformers installed in the distribution substations. The proposed algorithms are applied to several field measurements from different substations. The results show that the algorithms fulfill the requirements for the online measurement and monitoring of power system Thevenin, harmonic and zero sequence impedances as well as the load model parameters. / Energy Systems

High Voltage Direct Current (HVDC) transmission systems continue to be an excellent asset in modern power systems, mainly for their ability to overcome the problems of AC transmission, such as the interconnection of asynchronous grids, stability of long transmission lines, and use of long cables for power transmission. In the past 20 years, Voltage Source Converter (VSC)-HVDC transmission systems were developed and installed in many projects, thereby adding more operational benefits to DC transmission option, such as high controllability, ability to supply weak networks, and reduced converter reactive power demand. Nevertheless, VSC-HVDC transmission suffers from the disadvantages of high losses and cost. In this research, a hybrid HVDC employing a Line Commutated Converter (LCC) as rectifier and a VSC as inverter is used to supply a passive network through a DC cable. The hybrid system is best suited for unidirectional power transmission scenarios, such as power transmission to islands and remote load centers, where the construction of new transmission lines is prohibitively expensive. Control modes for the rectifier and inverter are selected and implemented using Proportional Integral (PI) controllers. Special control schemes are developed for abnormal operating conditions such as starting at light load and recovering from AC network faults. The system performance under steady state and transient conditions is investigated by EMTP-RV simulations. The results show the feasibility of the hybrid system. / UOIT

We use load balance technique, Linux Virtual Server. Cluster server system construct the efficient structure own high scalability and availability through connecting with high performance network or LAN. In addition, applications provide transmitting real-time video and audio are increasingly needed with network bandwidth increase. To fit the current trend and test the multimedia streaming support of LVS, we add streaming service into web cluster system. But the playing of stream is not smooth, when the system is running. Streaming have serious delay and so we propose transmitting stream directly. When user had chose stream media from web then the client connect with streaming server directly and play the media continually, so we improve the performance of streaming.

Customer load characteristics plays the ndamental role for more reliable load forecasting. It can also be used to enhance the system expansion planning and economic dispatch more effectively. Besides, the system capacity shortage due to peak loading can be relieved by the strategy of energy conservation and load management with customer load models. A systematic procedure is proposed in this thesis to study the effect of temperature change to the power system load demand by using the typical load patterns of customer classes. The billing data of all service customers are retrieved to derive the daily load profile of the selected Taipower district. To verify the accuracy of the estimated load composition, the simulation results are compared to the actual load profile collected by the SCADA system. The sensitivity analysis of load demand with respect to the temperature change for each customer class is performed by statistic regression according to the actual customer power consumption and temperature data. With temperature rise, the load contribution by each customer class is updated by the corresponding temperature sensitivity and integrated together to form the new load profile of the service district. In the future, the load research will play more important role for power utility companies. Load data will be utilized to a greater extent by various departments in utility companies. For instance, the proposed load survey system can solve the customer load characteristics more accurately to support various applications. By refer the temperature sensitivity analysis based on the customer load research, can evaluate the potential of air conditioner load management to reduce the system peak loading can be inhibit. With this information, the proper incentive of cycling control of air conditioners can be designed to achieve more effective load management.

In a more competitive environment, load forecast serves two different applications. First, load forecast results can be used by the retailers of power to study their opportunities and plan their business strategies. Second, accurate projections of load are useful for T&D operators in performing system operation and expansion studies. Several key elements in their market and system planning studies have strong location factors that the spatial load forecast can address. In this dissertation, a package that integrates a Geographic Information System (GIS) used for automatic mapping and facility management (AM/FM) and a spatial load forecast module is presented. The interface functions and the procedure of the fuzzy logic based spatial load forecast module are described. Simulation studies are performed on a metropolitan area of Kaohsiung, Taiwan. The conventional fuzzy modeling has a drawback in that the fuzzy rules or the fuzzy membership functions are determined by trial and error. In this dissertation an automatic model identification procedure is proposed to construct the fuzzy model for short-term load forecast. In this method an analysis of variance is used to identify the influential variables on the system load. To setup the fuzzy rules, a cluster estimation method is adopted to determine the number of rules and the membership functions of variables involved in the premises of the rules. A recursive least square method is then used to determine the coefficients in the conclusion parts of the rules. None of these steps involves nonlinear optimization and all steps have well-bounded computation time.

Thesis (M.S. in Meteorology and Physical Oceanography)--Naval Postgraduate School, March 2003. / Thesis advisor(s): Timothy P. Stanton, Edward B. Thornton. Includes bibliographical references (p. 79-83). Also available online.

Summary Residual stress dssess ment by means of the hole drilling techniqae is still regarded by many analysts as a phenomenon whose use is restricted to isotropic and homogeneous materials. The work caFried out in this paper tends to address this 'lack of certainty' through introdacing a verilication approach of experimentally assess ed residual stress values, The components investigated were produced under pure bending conditions and anulysed for their residual stress behaviour using a customized strain gaage rosette. This rosette was employed in order to detect the average and peak maximam strain relaxstion os a result of producing a hole by the high speed drilling technique. It is envisaged that the concept of the verffication method could lead to a better understanding with regard to residual stress analysis.