This dissertation presents the continued study of a non-iterative decision feedback (DF) receiver/decoder design and its application to cellular communications or wireless local loop systems based on the IS-95(-A) standard of the Telecommunications Industry Association and also Personal Communications Services systems based on the American National Standards Institute standard J-STD- 008-1996, which use code-division multiple access (CDMA) spread spectrum technology. Specifically, the DF decoder presented herein can be used in the uplink of these systems, which simultaneously uses a concatenation of convolutional coding, interleaving, and orthogonal Walsh modulation. The main contributions of this dissertation are the demonstration that the DF concept works well in multipath fading environments, the design of a new time-efficient decoding algorithm, and a new interleaver design. Initially, the performance of the DF decoder is assessed in unfaded as well as Rayleigh fading multipath propagation in additive white Gaussian noise interference. Simulation results using coherent and noncoherent detection are presented for both independent Rayleigh fading and Rayleigh fading with a commonly used Doppler spectrum. The results show improved performance compared to conventional non-DF receivers using the same decoding metric. This is a prerequisite for application of the DF decoder in an actual mobile communications environment. The effectiveness of the initial DF decoder design, as it is applied to IS-95 based systems, is studied. It is found that the effectiveness of the DF decoder is determined by the decoding delay of the convolutional decoder and the interleaver specification. Based on these findings, two methodologies to improve the effectiveness of the DF decoder are investigated. First, the average decoding delay is reduced using sub-optimal convolutional decoding. Second, the combination of a new block interleaver design and the DF decoder is considered. Simulation results of average decoding delay, bit error rate and frame error rate are presented for coherent and noncoherent detection of unfaded and Rayleigh fading multipath signals. It is shown that both approaches result in better system performance, which can further improve the quality of service and/or capacity of an IS-95 based system. Finally, a simplified analysis of the DF decoder performance is presented. / Graduation date: 1999

Thesis (Ph.D)--Stanford University, 1999. / Title from pdf t.p. (viewed April 3, 2002). "August 1999." "Adminitrivia V1/Prg/20000907"--Metadata.

Access control is a key feature of healthcare information systems. Access control is about enforcing rules to ensure that only authorized users get access to resources in a system. In healthcare systems this means protecting patient privacy. However, the top priority is always to provide the best possible care for a patient. This depends on the clinicians having access to the information they need to make the best, most informed, care decisions. Care processes are often unpredictable and hard to map to strict access control rules. As a result, in emergency or otherwise unexpected situations, clinicians need to be able to bypass access control. In a crisis, availability of information takes precedence over privacy concerns. This duality of concerns is what makes access control in healthcare systems so challenging and interesting as a research subject. To create access control models for healthcare we need to understand how healthcare works. Before creating a model we need to understand the requirements the model should fulfill. Though many access control models have been proposed and argued to be suitable for healthcare, little work has been published on access control requirements for healthcare. This PhD project has focused on bridging the gap between formalized models and real world requirements for access control in healthcare by targeting the following research goals:RG1 To collect knowledge that forms a foundation for access control requirements in healthcare systems.RG2 To create improved access control models for healthcare systems based on real requirements.This PhD project has consisted of a number of smaller, distinct, but relatedprojects to reach the research goals. The main contributions can be summarized as:C1 Requirements for access control in healthcare: Studies performed onaudit data, in workshops, by observation and interviews have helped discoverrequirements. Results from this work include methods for access controlrequirements elicitation in addition to the actual requirements discovered.C2 Process-based access control: The main conclusion from the requirementswork is that access control should be tailored to care processes. Care processesare highly dynamic and often unpredictable, and access control needs to adaptto this. This thesis suggests how existing sources of process information, bothexplicit and implicit, may be used for this purpose.C3 Personally controlled health records (PCHR): This thesis explores theconsequences of making the patient the administrator of access control andproposes a model based on these initial requirements. From a performedusability study it is clear that the main challenge is how to keep the patientinformed about the consequences of sharing.

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Several nice hardware functionalities located at the low level of operating system onmobile phones could be utilized in a better way if they are available to applicationdevelopers. With their help, developers are able to bring overall user experienceto a new level in terms of developing novel applications. For instance, one of thosehardware functionalities, SIM-card authentication is able to offer stronger andmore convenient way of authentication when compared to the traditional approach.Replacing the username-password combination with the SIM-card authentication,users are freed from memorizing passwords. However, since normally those kindsof functionalities are locked up at the low level, they are only accessible by a fewusers who have been given privileged access rights. To let the normal applicationsbe benefiting as well, they need to be made accessible at the application level. Onthe one hand, as we see the benefit it will bring to us, there is a clear intentionto open it up, however, on the other hand, there is also a limitation resultingfrom their security-critical nature that needs to be placed when accessing whichis restricting the access to trusted third parties. Our investigation is based on the Android platform. The problem that we havediscovered is the existing security mechanism in Android is not able to satisfy everyregards of requirements we mentioned above when exposing SIM-card authenticationfunctionality. Hence, our requirement on enhancing the access control modelof Android comes naturally. In order to better suit the needs, we proposed a solutionWhite lists & Domains (WITDOM) to improve its current situation in thethesis. The proposed solution is an extension to the existing access control modelin Android that allows alternative ways to specify access controls therefore complementingthe existing Android security mechanisms. We have both designedand implemented the solution and the result shows that with the service that weprovided, critical functionalities, such as APIs for the low-level hardware functionalitycan retain the same level of protection however in the meanwhile, with moreflexible protection mechanism.

TFT-LCD industries in Taiwan nowadays have confronted the condition of market¡¦s fast change. The trade shall have to substantially shorten the research and development span of products and also have to inseparably integrate the production system among upper, middle and lower reaches industries so as to advance the enterprise¡¦s competitiveness in the global markets. Therefore, the enterprises have implemented PLM and PDM system in droves to assist in effectively integrating the control and working of all the related information of products and the related operation of the products information during the life cycle of the products. The activity of engineering change is regarded as an essential part to the enterprise¡¦s improving the quality of products and reducing production cost and satisfying the customers¡¦ requirements. There are always possible engineering changes while carried out in each stage of the whole life cycle of products development. Consequently, a rationalized and standardized engineering change management system has then become obviously important to the existence competitiveness of the industries. By ways of case discussion, the study is to research a practical case through PLM system methodology and to confer the design methods of information access subsystem mode applied to the engineering change management module when TFT-LCD industries have implemented PLM system so as to test and verify if the effectiveness of implement is able to satisfy the operation management requirement of the engineering change. Through the analysis of implement process, the study also expects to obtain some rules of experiences as references when the future industry implements the Product life cycle management system.

Transportation is frequently cited as a barrier to health care, but rarely have researchers analyzed the problems in depth. The purpose of this study was to assess the role transportation plays in the utilization of preventive health care services among Medicaid recipients ages 0 - 20 in Texas. This preventive care is known as Early Periodic Screening and Diagnostic Testing (EPSDT), a comprehensive prevention and treatment program for Medicaid eligible children. Our computer assisted telephone interviewing based survey was administered to Medicaid recipients selected from a representative sample through a stratified sampling scheme. Binary logistic regression models were used to assess and predict factors associated with utilization of the Texas Medicaid Transportation Program (MTP) and utilization of EPSDT. We also used k-means cluster analysis to identify subgroups of Medicaid clients with particularly acute transportation barriers. Of the 1,214 Medicaid recipients interviewed, the overall odds of a Medicaid recipient being a MTP non-user was 0.94. For clients with automobile access, the probability increases to 0.98. Clients who experienced difficulties paying for gasoline decreased the overall odds to 0.86. When examining utilization of EPSDT, the overall probability of being a low utilizer was 0.59. Two factors, Spanish-speaking patients (0.21) and clients with more than one child at home (0.54) decreased the overall odds of being a low utilizer, while those with difficulty paying for gasoline increased the odds of being a low utilizer to 0.63. Increasing EPSDT utilization among the millions of Texas Medicaid recipients is an important policy objective. Because the Texas Medicaid population is large and diverse, no single approach to increasing utilization is likely to address all needs. The group concept provides a means to understand which Medicaid recipients do not access MTP services and those with low utilization rates. These groupings can be useful in targeting Medicaid clients with specific transportation difficulties. Instead of broad informational campaigns, policy makers should devise targeted strategies to promote the most appropriate types of assistance. In addition to expanding transportation options, policy makers should also examine the locations in which care is delivered, considering telemedicine, mobile health and school-based health clinics as options.

Thesis (M.S.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Tri T. Ha, Jan E. Tighe, David C. Jenn, Jovan Libaric. Includes bibliographical references (p. 133). Also available online.

Thesis (M.S.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Tri T. Ha, Jan E. Tighe, David C. Jenn. Includes bibliographical references (p. 97). Also available online.

Thesis (M.A.)--University of Hong Kong, 2001. / Includes bibliographical references.