Research has focused on how the effects of different types of feedback vary as a function of the complexity of the linguistic targets and on the learning of inflectional features. However, few studies have investigated the learning of rule-based verb constructions. Grounded in the interactionist approach and usage-based theory, this study investigated the effects of corrective feedback on the acquisition of rule-based verb constructions among English-speaking learners of Chinese. Specifically, this study examined the effects of input-providing feedback and output-prompting feedback on the learning of two verb constructions. Data were drawn from 18 learners of Chinese from second-year Chinese classes in an American university. The participants were divided into two groups and took a pretest, treatment, and two posttests. Learners also filled out a questionnaire about their perception and preference of feedback types. Contrary to previous research, results indicated that both recasts and metalinguistic clues had positive effects on learners' learning of the target constructions. Moreover, learners of different proficiency preferred different types of feedback. The study results provided a categorization of verb constructions into four classes based on the rules that govern their formations and constraints that work on the constructions and identified stages learners moved through when learning verb constructions. The researcher proposed an instructional model of rule-based verb constructions. The model will help instructors recognize the stage the learners' are in and provide insight into how to help learners move to a higher stage by providing instruction, corrective feedback, and practice activities.

This is a verification of the results of “Smart Grid Protection through Self-Healing” from the publication of Chathurika Chandraratne, et al., that proposes a protection solution for the smart grid. The paper used as reference has as the main focus on three different protections; directional overcurrent protection, overcurrent protection, and transformer protection, which are validated through ETAP software simulation of IEEE- 9 bus and 14 bus electrical power systems, the same used by the author. It was validated after repeated simulation, that just as intended, self-healing increases system agility, and it helped prevent false-tripping14 bus electrical power systems.

Guidewires have been used in many operating rooms by vascular surgeons to assist them in positioning and maneuvering through a tortuous stenosis or lesion to a desired location, and to be used as a guide for the implantation of a catheter. Surgeons are tasked with having to insert a guidewire inside a small cavity, which requires a high level of skill and patience. The insertion of the guide wire is controlled by a torque device, which allows a surgeon to advance, rotate and grip the wet hydrophilic coating of the guidewire. Despite its many advantages, the torque device does, in fact, give rise to many time consuming issues that results in delays to the surgical procedure. One main problem in the use of the torque device is that it is introduced through the proximal end of the guidewire. Therefore, it requires the assistance of another individual, the surgical technician, to advance the torque device from the furthest point away from the patient. Once the torque device is in position, it is up to the surgeon to attempt to control the tightening, advancing and loosening of the device all with one hand. The other, free hand is used as a placement hand to secure the positioning of the guidewire within the patient. Another issue arises in the removal of the torque device, which must be loosened with one hand and slid off the same end it was introduced, often resulting in the unwanted ejection of the guide wire tip from within the patient's body. The process must then commence from the start, resulting in loss of valuable time, and be repeated until the distal tip of the guidewire is secure in the desired location and the catheter can now be introduced. The main purpose of this research is to investigate, design, and develop a new guidewire torque device to facilitate in a more controlled manipulation of a guidewire by vascular surgeons. Through in-depth interviews with both surgeons and surgical residents alike, direct observational time in the vascular surgery OR (operating room), and I obtained knowledge used as a design basis for the development of the product. For example, observations of relevant medical procedures were also accomplished at Tampa General Hospital to establish a basis for the design,and to assess current vascular surgery medical procedures. Initial design concepts where created using SolidWorks CAD software. After a period of researching and understanding user needs, an assortment of non-slip adhesives where found to be a viable solution to the problem. A characterization analysis was done on the highest rated non-slip adhesive to further define design parameters, and pave the way for FDA approval and product commercialization.

This thesis is concerned primarily with the optimization of the current regulation in bi-directional ac-dc power converters through the use of appropriate current control methods. Following a review into prior current control technology, current control methods which attempt to achieve Zero Average Current Error (ZACE) in each switching period are presented. A ZACE controlled converter offers independent real and reactive power flow control with negligible low order current harmonics, a relatively narrow switching frequency band, and relative immunity to power circuit parameter variations, including DC link or AC line voltage harmonics. ZACE and other desirable characteristics in a current control method are discussed. The single phase ac and dc ripple current is characterized.Two new types of ZACE current control techniques for directly controlling the inductor current in switched power converters are introduced in this thesis together with variations for certain applications. Slope-generated hysteresis (SGH), the first to be developed, is a hysteresis method which uses the slopes of the current error signal alone to generate a hysteresis band which will result in a fixed switching frequency. Slope-generated hysteresis-clock (SGHC) is presented as an alternative with a dual clock to force a narrow switching frequency band.Ramptime current control is the second type of ZACE current control presented. Developed as an improvement over SGH, ramptime produces ZACE in each switching period by using the timing of a previous switching instant relative to the coincident previous current error signal excursion time to determine each switching instant. The digital current error polarity signal is the only variable input required to produce a pwm output.Variations of ramptime current control are also presented. Polarized ramptime is a subset of ramptime which maintains a narrow ++ / switching frequency band despite switching delays. Dual ramptime is the final enhancement of ramptime where two polarized ramptime regulators are used together to provide the appropriate choice between full-bridge and half-bridge switching in a single phase current controlled full-bridge voltage source inverter with the ac ripple current minimized without compromising the transient response. Using this technique, excellent fidelity and a narrow switching frequency band are demonstrated.The ZACE current control techniques are applied to a three phase voltage source inverter. A "standing phase" system of control for a three wire, three phase inverter is chosen over individual phase control since only two current regulators are required to control two decoupled current error signals, and the effective switching frequency is reduced by one third.The new ZACE methods are found to compare favourably in simulation to existing linear and hysteresis type current control techniques. SGH current control has equivalent fidelity to any other hysteresis control in delivering the reference current waveform, but is prone to noise in the hysteresis band determination requiring filtering. This, combined with the effect of switching delays compromises the narrowness of the switching frequency band. SGHC current control is also prone to noise in the generation of the hysteresis band, and results in a decrease in the fidelity of reproduction of the reference waveform. Ramptime current control is a robust technique, largely immune to power circuit parameter and voltage variances, with good fidelity and a relatively narrow switching frequency band. Polarized ramptime current control is shown to produce excellent fidelity with a narrow switching frequency band.The operation of the ZACE methods in single and three phase prototype converters is demonstrated. A field installation of a ++ / grid-connected ramptime current controlled converter is shown to source 20 kW of real power onto the grid from a photovoltaic array with a maximum power point tracking control, while independently providing grid voltage support through reactive power control.The effect of the synchronization of the current regulators on the ac and dc current ripple are presented. Synchronized polarized ramptime regulators are shown to produce the minimum ripple current in simulation and in the prototype operation.ZACE current control techniques, and ramptime and polarized ramptime in particular, are presented as a significant contribution to the control of current in power electronic converters.

Wireless communication systems are increasingly deployed by family, businesses, government and SOHO users because of the freedom wireless communications afford, simplicity of installation and ease of use. Along with its rapid development, the security problem in wireless communication network has attracted more and more attention. It has been estimated that the IEEE 80.211 standard is susceptible to attacks both on data content and user authentication, such as eavesdropping, spoofing and Denial of Service. These attacks are due to the standard's inherent flaws and space signal sharing caused by the omni-directional antenna it usually uses. In recent years, few studies have been undertaken which examine the use of the smart directional antenna to mitigate the security risks in mobile wireless computing networks. One of the major reasons is the antenna size, as portability is a key requirement. Due to the dielectric-material embedding and FDTD optimal design technology, a smart antenna with controllable directionality can now achieve an overall volume reduction of 80%. This has promise for application in the wireless security realm. This thesis provides a conventional background in wireless computing networks and security theory. In addition, security level definition, program in Matlab™ and corresponding experimental results are provided. To show the effectiveness of improving security in WLAN with the use of a smart directional antenna, this thesis proposes a model for predicting electromagnetic environments using a directional transmission antenna based on the Finite Element method. To validate the numerical results, a new experimental method (using Network Stumbler software) to measure the signal strength in different locations is introduced. Results from experiments using the two methods are consistent. The latter method gives the users the possibility of using a laptop (with an appropriate wireless card, software and roguing around) to detect the real-time signal strength in different locations instead of using expensive measure apparatus. Such an advantage can be valuable for the efficient implementation of indoor wireless networks for security purposes. Finally, it contributes a security solution using DE-ESMB and DE-ESPAR smart antennas in WLAN. Through these simulated and experimental results, one can conclude that the security performance in WLAN can be greatly improved by using smart directional antenna. There are five chapters in this thesis: Chapter 1 introduces the wireless communication network. Information about architecture, topology and popular wireless standards is presented in this chapter. Chapter 2 investigates the security problem in IEEE 802.11 Standards. Recent improvements in security, and their limitations, are also included. This problem is investigated by performing laboratory experiments, including a real attack on 802.11 Standards and packet capture experiments using AiroPeek NX software. Chapter 3 describes the useful parameters of smart directional antennas, and then presents the security level definition in WLAN. Simple software in Matlab™ to determine the security level according to the beamwidth of the adopted antenna is also introduced. Chapter 4 is the important part of this thesis. Simulation results of signal strength in different locations using FEMLAB™ are presented, which are consistent with the follow-up experimental results carried out in a typical office area. This chapter also describes the final security solution using the newly-designed DE-ESMB and DE-ESPAR directional antennas. Chapter 5 is a summary of the thesis. It presents the conclusions and suggests area of future research for improving the security level using smart antennas in WLAN.

<p>Elevated levels of anxiety are a common response to stressful competitive sports situations, are known to moderate athletic performance and are referred to as an unpleasant emotional state associated with perceptions of situational threat. The empirical studies in this dissertation considered primarily psychometric, methodological and conceptual issues of relevance for the study of anxiety and sports performance. In Study I, athletes were followed across a full competitive season to explore patterns of inter- and intra-individual variability of anxiety and self-confidence in relation to performance. The findings imply intra-individual anxiety and self-confidence variability to affect performance differently than the specific intensity level and are discussed in relation to more stable personality dispositions such as private self-consciousness. Study II evaluated the psychometric properties of the 27-item Competitive State Anxiety Inventory-2 (CSAI-2) and alternative versions of this scale. General support for a 17-item version (CSAI-2R) was found, but there are also psychometric limitations future research needs to resolve. Study III investigated assessment of intensity and directional ratings on single anxiety items with reference to the conceptualisation of anxiety symptoms as interpreted on a debilitative-facilitative continuum. The findings question the importance and rationale of assessing anxiety direction and revealed serious concerns with assessment procedures and statistical techniques applied in previous research. These concerns were also supported in Study IV, which explored athletes’ idiosyncratic experiences of debilitative and facilitative anxiety symptoms in terms of intensity and emotional valence. The findings are discussed and summarised in a model in order to increase conceptual clarity and provide implications for future research regarding anxiety and related emotional performance states.</p>

<p>Syftet med denna uppsats är att identifiera olika utvecklingsmöjligheter som Apoteket AB har på den avreglerade apoteksmarknaden. Genom att analysera attraktiviteten i de olika möjligheterna är ambitionen att ge rekommendationer om framtida verksamhetsinriktningar där bolaget kan uppnå en positiv utveckling. För att identifiera utvecklingsmöjligheterna har djupgående intervjuer med personer inom Apoteket AB genomförts. Den empiriska informationen har analyserats med hjälp av en SWOT-analys samt en Directional Policy Matrix (DPM). Utifrån detta har en bedömning av marknadens attraktivitet samt företagets konkurrensförmåga genomförts för att bestämma respektive utvecklingsmöjlighets attraktivitet. I undersökningen identifierades fem potentiella utvecklingsmöjligheter. Resultatet visade att Apoteket AB har goda förutsättningar att satsa på internethandel, grossistverksamhet samt samarbete med en annan aktör. De rådande stand-still-direktiven hindrar Apoteket AB att vidta konkurrenskraftiga åtgärder tills de nya aktörerna etablerat sig. Grossistverksamhet och samarbete med andra aktörer kan därmed realiseras först när direktiven upphör. Med detta sagt är internethandel den enda av de attraktiva möjligheterna som bolaget i nuläget tillåts verkställa. För en differentiering mot särskilda sortiment och kundgrupper samt för vidare internationalisering har Apoteket AB i dagsläget inte tillräckligt med styrkor för att matcha dessa möjligheter. I framtiden kan dock mycket förändras och det gäller för Apoteket AB att omvandla sina svagheter till styrkor samt vara proaktiva så att fler utvecklingsmöjligheter kan realiseras.</p>

The performances of high-speed network communications frequently rest with the distribution of data-stream. In this paper, a dynamic data-stream balancing architecture based on link information is introduced and discussed firstly. Then the algorithms for simultaneously acquiring the passing nodes and links of a path between any two source-destination nodes rapidly, as well as a dynamic data-stream distribution planning are proposed. Some related topics such as data fragment disposal, fair service, etc. are further studied and discussed. Besides, the performance and efficiency of proposed algorithms, especially for fair service and convergence, are evaluated through a demonstration with regard to the rate of bandwidth utilization. Hoping the discussion presented here can be helpful to application developers in selecting an effective strategy for planning the distribution of data-stream. / Singapore-MIT Alliance (SMA)

Directional wave-field decomposition for heterogeneousanisotropic media with in-stantaneous response is establishedfor both the acoustic and the electromagnetic equations. We derive a sufficient condition for ellipticity of thesystem's matrix in the Laplace domain and show that theconstruction of the splitting matrix via a Dunford-Taylorintegral over the resolvent of the non-compact, non-normalsystem's matrix is well de ned. The splitting matrix also hasproperties that make it possible to construct the decompositionwith a generalized eigenvector procedure. The classical way ofobtaining the decomposition is equivalent to solving analgebraic Riccati operator equation. Hence the proceduredescribed above also provides a solution to the algebraicRiccati operator equation. The solution to the wave-field decomposition for theisotropic wave equation is expressed in terms of theDirichlet-to-Neumann map for a plane. The equivalence of thisDirichlet-to-Neumann map is the acoustic admittance, i.e. themapping between the pressure and the particle velocity. Theacoustic admittance, as well as the related impedance aresolutions to algebraic Riccati operator equations and are keyelements in the decomposition. In the electromagnetic case thecorresponding impedance and admittance mappings solve therespective algebraic Riccati operator equations and henceprovide solutions to the decomposition problem. The present research shows that it is advantageous toutilize the freedom implied by the generalized eigenvectorprocedure to obtain the solution to the decomposition problemin more general terms than the admittance/impedancemappings. The time-reversal approach to steer an acoustic wave eld inthe cavity and half space geometries are analyzed from aboundary control perspective. For the cavity it is shown thatwe can steer the field to a desired final configuration, withthe assumption of local energy decay. It is also shown that thetime-reversal algorithm minimizes a least square error forfinite times when the data are obtained by measurements. Forthe half space geometry, the boundary condition is expressedwith help of the wave-field decomposition. In the homogeneousmaterial case, the response of the time-reversal algorithm iscalculated analytically. This procedure uses the one-wayequations together with the decomposition operator.

Elevated levels of anxiety are a common response to stressful competitive sports situations, are known to moderate athletic performance and are referred to as an unpleasant emotional state associated with perceptions of situational threat. The empirical studies in this dissertation considered primarily psychometric, methodological and conceptual issues of relevance for the study of anxiety and sports performance. In Study I, athletes were followed across a full competitive season to explore patterns of inter- and intra-individual variability of anxiety and self-confidence in relation to performance. The findings imply intra-individual anxiety and self-confidence variability to affect performance differently than the specific intensity level and are discussed in relation to more stable personality dispositions such as private self-consciousness. Study II evaluated the psychometric properties of the 27-item Competitive State Anxiety Inventory-2 (CSAI-2) and alternative versions of this scale. General support for a 17-item version (CSAI-2R) was found, but there are also psychometric limitations future research needs to resolve. Study III investigated assessment of intensity and directional ratings on single anxiety items with reference to the conceptualisation of anxiety symptoms as interpreted on a debilitative-facilitative continuum. The findings question the importance and rationale of assessing anxiety direction and revealed serious concerns with assessment procedures and statistical techniques applied in previous research. These concerns were also supported in Study IV, which explored athletes’ idiosyncratic experiences of debilitative and facilitative anxiety symptoms in terms of intensity and emotional valence. The findings are discussed and summarised in a model in order to increase conceptual clarity and provide implications for future research regarding anxiety and related emotional performance states.