Optical beam induced current mapping has found wide-spread applications in charactering semiconductor devices and integrated circuitry. Conventionally a focused cw laser beam is employed to excite carriers in the depletion region that is subsequently detected to form the contrast signal for scanning imaging. Device defects that may quench the photo-generated carriers can then be easily revealed. However, such detection is static in nature and the dynamics behavior of a device remains unknown. In this study, we are using a pulsed laser with high repetition rate and a high frequency phase sensitive lock-in loop to achieve temporal resolution at sub-nanosecond. In this way, the temporal response at a selected position on the device can be characterized

As the great studies have been made in light emitting diodes, the application becomes more variety for different field. High bright light emitting diodes apply a new light source for fluorescence lifetime measurements. We use confocal scanning microscopy and a high frequency sensitive lock-in amplifier to obtain the electroluminescence image at ten of micrometer. We drive the light emitting diodes by radio frequency signal and observe it. We parallel connection an inductance to match the parasitic capacity in high frequency to obtain better light emitted brightness.

The advances of information technologies have forced many enterprises to reconsider the way their business processes are conducted. Among the various information technologies, workflow management systems (WFMSs) are widely recognized as an effective tool to greatly improve the efficiency of business processes and customers¡¦ satisfaction. Today, a great number of commercial WFMSs have been available on the market; however, none of them are very successful due to the lack of some important features. One of the features that are needed by many business processes is the specification and enforcement of time constraints. In this thesis, we propose a time constraint model that helps workflow designer to define and verify time constraints. Different constraints may be verified at different times, e.g., definition time, invocation time, execution time. A workflow instance, once detected as a violation of some time constraint, could be terminated immediately to avoid the waste of precious resources as well as to provide prompt response to users. A variety of algorithms for verifying time constraints are proposed and analyzed.

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The limit of bandwidth efficiency is well known in wireless radio communication. Therefore, making use of bandwidth efficiently is very important. Among various technologies which can increase the bandwidth efficiency, space-time coding system is very popular technology recently. In this article, we¡¦ll discuss three common schemes in ST system¡GSpace-Time Trellis Coding (STTC), Space-Time Block Coding (STBC) and Differential Space-Time Block Coding (DSTBC). First, we¡¦ll introduce the basic model of ST systems in chapter 2. And in chapter 3, the error probability, which is a close form, of STBC and DSTBC systems in slow fading channel will be derived, according to the derivation of error probability in multi-channel communication systems¡i10¡j. Then, the channel model will be defined as a fast fading channel and the error probability of STBC system in this channel model will be derived in chapter 4. Furthermore, we¡¦ll derive the error probability of STBC system in multi-path slow fading channel. Finally, we¡¦ll make a conclusion to the works we did in this article. The contribution of this article are¡G1. We derive a bit error probably which is a close form of STBC and DSTBC systems in slow fading channel. 2. We analyze the performace of STBC system in fast fading channel and derive a bit error probability in this case. 3. We analyze the performance of STBC system in multi-path slow fading channel and get a result that the diversity gain will increase when use the RAKE receiver mentioned in this article.

Time of concentration parameter is defined very loosely in literature and it is calculated rather subjectively in practice (Akan 1986). The situation becomes adverse as the terrain slope approaches zero; because the slope generally appears in the denominator of any formula for time of concentration, this time goes to infinity as the slope goes to zero. The variables affecting this time parameter on flat terrains have been studied through plot scale field experiments. It has been found that the antecedent moisture and rainfall rate control this parameter. Some of the existing time of concentration methods have been compared, and it is found that all the empirical models compared under predict this time parameter. This under prediction can be attributed first to the differing concepts of time of concentration previous researchers have modeled, secondly to the absence of any accounting for the initial moisture content in their respective equations and thirdly to the watersheds where these models have been calibrated. At lower time of concentrations, Izzard-based model predictions show some results close to the observed values. A methodology to determine the plot scale surface undulations has been developed to estimate the depression storage. Regression equations have been derived based upon the experiments to determine the overland flow times on a flat plot of 30 feet length with uniform rainfall intensity. The application of these equations on other lengths cannot be ascertained. Equations for the hydrograph slope on flat terrains have been determined for bare clay and grass plots.

The lymphatic system consists of a network of vessels which work to return the interstitial fluid back to the blood circulation. Individual units called lymphangions, segments of lymphatic vessels between two valves, pump cyclically to propel lymph. Lymphangions are similar to the heart in that they are sensitive to both preload and afterload. To describe the heart independent of preload and afterload, investigators developed the concept of time-varying elastance. We evaluated the applicability of this concept to lymphangions by analyzing preliminary data obtained from the bovine mesenteric vessels. We found that there were some limitations to the applicability of this concept to lymphangions, as there was a high degree of variability with respect to contraction strength and frequency of individual time-varying elastance curves. To better characterize lymphangion mechanics, we built a device which would enable real-time isobaric, isometric and isotonic experiments in vitro. We performed all three experiments on lymphatic vessel segments and obtained input and output pressures, output flow, instantaneous radii and wall tension. The characterization of the lymphangion using these parameters can be the first step to simulate the behavior of a lymphatic vesssel and later the behavior of an entire lymphatic system.

This research is related to time management and the use of timesheets in architectural design education. It focuses on the role of Web-based timesheets in the architectural design studio. The main purpose of the research is to explore whether Web technology is helpful in increasing compliance with time documentation and can determine which student behaviors and habits can be observed with Web-based timesheets in architectural design education. In time management, using timesheets is a common method to analyze time usage. However, a traditional timesheet is usually focused on the investigator's (teacher or employer) perspective. Therefore active participation is hardly expected and data analysis is not easily offered to participants as useful information in real time. To overcome the identified problems, Web technology may be useful. For this research, a pilot software tool was developed and tested in design studios at several grade levels. Research was focused on empirical observation to determine which student work patterns and behaviors can be observed with a Webbased timesheet tool. The Web-based timesheet tool was successfully fielded in the design studio and the utility of the Web-based timesheet tool was observed. By analyzing the collected data from the experiments with this Web-based timesheet tool, it was possible to observe various work patterns and behaviors and to develop insights in the students' design process. Analysis of log data gave interesting insights into students' work patterns and design behaviors. Web technology was helpful in increasing the value of the timesheet in architectural design education.

The increased prevalence of childhood obesity is a major concern for society. This study aims at exploring the influence of the parents (especially parental time allocation choices) on children’s obesity-related health outcomes and examining the potential differences between the fathers’ and the mothers’ marginal effects. A household with two parents and one child is modeled. The household production theory and the collective household modeling structure are combined. The model treats the mother, the father and the child as three separate agents with individual preferences. The two parents’ interaction is modeled within the collective model framework by assuming that they will reach Pareto efficient resource allocation between them. In order to capture the dynamics between parents and the child, parents-child interaction is modeled in a two-stage Stackleberg game structure where the child is allowed to have certain decision choices of his/her own. This game structure allows us to explore the parental influence on the child’s health outcomes while allowing the child to have influencing power in the household decision-making process. Based on this theoretical model, a general triangular system with one child’s health production equation and five health inputs demand equations is derived and estimated. The empirical estimation is performed for three systems: pooled model, the younger children model (of age 9 to 11), and the older children model (of age 13 to 15). The empirical results show mother-related variables show more influence on the child’s Body Mass Index (BMI) outcomes compared to father-related variables: mothers’ BMI and mothers’ work-to-home stress spillover are positively related to their children’s BMI while mothers’ time spent with their children is negatively related to their children’s BMI. There exists a complementary relationship between mothers’ income and fathers’ food preparation time. In the older children model, mothers’ own income increases tend to decrease their time spent with their children. The main contribution of this study is that it develops a general theoretical framework to capture the dynamics in parents-child interaction. Based on this theoretical model, empirical analysis and future work can be conducted in a theoretically consistent way.

Thesis (D. Min.)--Midwestern Baptist Theological Seminary, 2008. / Abstract. Includes bibliographical references (leaves 112-113)