Automatic analysis of distance bounding protocols

Distance bounding protocols are used by nodes in wireless networks to calculate upper bounds on their distances to other nodes. However, dishonest nodes in the network can turn the calculations both illegitimate and inaccurate when they participate in protocol executions. It is important to analyze protocols for the possibility of such violations. Past efforts to analyze distance bounding protocols have only been manual. However, automated approaches are important since they are quite likely to find flaws that manual approaches cannot, as witnessed in literature for analysis pertaining to key establishment protocols. In this paper, we use the constraint solver tool to automatically analyze distance bounding protocols. We first formulate a new trace property called Secure Distance Bounding (SDB) that protocol executions must satisfy. We then classify the scenarios in which these protocols can operate considering the (dis)honesty of nodes and location of the attacker in the network. Finally, we extend the constraint solver so that it can be used to test protocols for violations of SDB in these scenarios and illustrate our technique on some published protocols.Comment: 22 pages, Appeared in Foundations of Computer Security, (Affiliated workshop of LICS 2009, Los Angeles, CA)

Study of a High-Efficient Wide-Bandgap DC-DC Power Converter for Solar Power Integration

This research focuses on the design and analysis of a Boost cascaded Buck-Boost (BoCBB) power converter with super high efficiency in electric power conversion. The BoCBB power converter is based on emerging wide-bandgap silicon-carbide (SiC) MOSFETs and Schottky diodes, which have only 1/6 times of power loss in traditional silicon power semiconductor devices. The BoCBB power converter can be widely applied in solar harvesting for the National Aeronautics and Space Administration (NASA), military bases and electric utilities, as well as high-power DC motor drives for the electric vehicles, robotics, and manufacturing and product lines. This research analyzed the topology and energy efficiency of a 3-kW BoCBB power converter. The energy efficiency of the SiC-based BoCBB power converter was calculated under various switching frequencies (20-kHz – 100-kHz) and was first tested by a simulation study of solar power integration in a 400-Vdc distribution microgrid in Matlab/Simulink environment. The design of 50-kHz in switching frequency revealed to be optimal in overall system performance. This conclusion was further verified by experimental tests. The experimental tests demonstrated a high efficiency of above 97% in power conversion. In order to improve the power quality of the BoCBB power converter for time-varying solar radiation, a novel sliding-window-combined (SWC) hysteresis control technique was proposed and preliminarily verified by a simulation study to enhance transients of a power grid

Optimization of 8-Plate Multi-Resonant Coupling Structure Using Class-E\u3csup\u3e2\u3c/sup\u3e Based Capacitive-Wireless Power Transfer System

Capacitive-wireless power transfer (CPT) effectively charges battery-powered devices without a physical contact. It is an alternative to inductive-wireless power transfer (IPT) which is available in the present market. Compared with IPT, CPT offers flexibility in designing the coupling section. Because of its flexibility, CPT utilizes various coupling methods to enhance the coupling capacitance. Misalignment is a common issue in any WPT system. Among IPT and CPT, IPT has better performance for misalignments, but it requires bulk and expensive ferrite core to attain a high coupling coefficient. This work focuses on designing a CPT system to minimize the impact of misalignments. In this research, a novel 8-plate multi-resonant Class-E2 CPT system is developed to improve the performance of the CPT system for misalignments. The proposed CPT model expands the resonant frequency band, which results in better performance for misalignments compared with the regular 4-plate CPT system. The 8-plate coupling structure is designed to charge a 100 Ah drone battery. For this application, the coupling is formed when the drone lands on the capacitive- wireless charging pad. This work also presents the analysis of several dielectric materials with different dielectric constants. A well-designed capacitive coupler can effectively limit harmonics during the interaction between transmitter and receiver. Also, the effect of coupling plate shape is identified on the CPT system. The hardware tests indicate the round-shaped plates have better stability in coupling capacitance with the variation in frequency. The effect of misalignments is studied through the impedance tracking of the Class-E2 power converter. Impedance plots for 50 μH, and 100 μH resonant inductors are used to determine input current peak for each case. Additionally, hardware tests are performed to study the variation of input current and output voltage for a range of frequencies. The test results indicate the efficiency at optimal impedance point for a resonant inductor with 50 μH is 8% higher compared to the CPT with a 100 μH resonant inductor which highlights the effects of the resonant inductor on efficiency. The zero-voltage-switching (ZVS) limits are also identified for varying frequencies and duty cycles. Later in this research, the optimal design of the Class-E rectifier is identified to enhance the power transfer. Several cases were considered to investigate the impact of the secondary inductor on the output voltage and the ZVS property. Hardware tests validate that under optimal conditions the efficiency of the Class-E2 based CPT system improves by 18% compared with Ar \u3e\u3c 1. Further work presents the advantages of 8-plate multi-resonant coupling for misalignments. The proposed model has a simple design procedure which enhances the power flow from the inverter to the rectifier section. The hardware results of the proposed 8-plate multi-resonant coupling show an increase in efficiency to 88.5% for the 20.8 W test, which is 18% higher than regular 4-plate coupling. Because of the wider resonant frequency band [455- 485 kHz], compared with regular 4-plate coupling, the proposed design minimized the output voltage drop by 15% for 10% misalignment. Even for large misalignments, 8-plate improves the CPT performance by 40% compared with 4-plate coupling

A Case Study: Influence of Circuit Impedance on the Performance of Class-E² Resonant Power Converter for Capacitive Wireless Power Transfer

The evolution of power electronics led to rapid development in wireless charging technology; as a result, a single active switch topology was introduced. The present market utilizes inductive wireless power transfer (IPT); because of the disadvantages of cost, size, and safety concerns, research on wireless power transfer was diverted towards capacitive wireless power transfer (CPT). This paper studies the optimal impedance tracking of the capacitive wireless power transfer system for maximum power transfer. Compared to prior methods developed for maximum power point tracking in power control, this paper proposes a new approach by means of finding impedance characteristics of the CPT system for a certain range of frequencies. Considering the drone battery as an application, a single active switch Class-E2 resonant converter with circular coupling plates is utilized. Impedance characteristics are identified with the help of equations related to the input and resonant impedance. The impedance tracking is laid out for various resonant inductors, and the difference in current peak is observed for each case. Simulations verify and provide additional information on the reactive type. Additionally, hardware tests provide the variation of input current and output voltage for a range of frequencies from 70 kHz to 300 kHz. Efficiency at the optimal impedance points for a resonant inductor with 50 μH and 100 μH are tested and analyzed. It is noted that the efficiency for a resonant inductor with 50 μH is 8% higher compared to the CPT with a 100 μH resonant inductor. Further hardware tests were performed to investigate the impact of frequency and duty cycle variation. Zero-voltage-switching (ZVS) limits have been discussed with respect to both frequency and duty cycle

8-Plate Multi-Resonant Coupling Using a Class-E\u3csup\u3e2\u3c/sup\u3e Power Converter For Misalignments in Capacitive Wireless Power Transfer

Misalignment is a common issue in wireless power transfer systems. It shifts the resonant frequency away from the operating frequency that affects the power flow and efficiency from the charging station to the load. This work proposes a novel capacitive wireless power transfer (CPT) using an 8-plate multi-resonant capacitive coupling to minimize the effect of misalignments. A single-active switch class-E2 power converter is utilized to achieve multi-resonance through the selection of different resonant inductors. Simulations show a widening of the resonant frequency band which offers better performance than a regular 4-plate capacitive coupling for misalignments. The hardware results of the 8-plate multi-resonant coupling show an efficiency of 88.5% for the 20.8 W test, which is 18.3% higher than that of the regular 4-plate coupling. Because of the wider resonant frequency band {455–485 kHz}, compared with the regular 4-plate coupling, the proposed design minimized the output voltage drop by 15% for a 10% misalignment. Even for large misalignments, the 8-plate performance improved by 40% compared with the 4-plate coupling

Achieving Quality of Service in Group Scheduling in Cellular Networks

Title from PDF of title page, viewed on July 17, 2014Thesis advisor: Cory BeardVitaIncludes bibliographic references (pages 51-55)Thesis (M. S.)--School of Computing and Engineering. University of Missouri--Kansas City, 2014Cellular 3G/4G networks provide a wonderfully rich set of applications and social networking capabilities. From a QoS perspective, the traffic is basically divided into Real time and Non real time traffic which helps in scheduling priorities to the packets. With increase in need for QoS in the commercial networks, scheduling schemes such as MLWDF (Modified Largest Weighted Delay First) are playing a prominent role in deciding factors of packet selection. But most of these features are not available to public safety and emergency organizations where these organizations must use dedicated systems to obtain the reliability and protected performance that is needed. This research work provides a brief survey of the regulatory and commercial issues involved. The research work then provides solutions to give real-time and non-real-time traffic scheduling priorities to balance different requirements. We introduce the concept of a queue indicator that uses queue awareness to decide which traffic type to transmit. Then we introduce the concept of group scheduling that adds together scheduling metrics of different users within groups to decide which groups should transmit. These metrics are both opportunistic to take advantage of changing channel conditions and they are queue aware to adapt to traffic conditions. But the metrics are very simple so that scheduling mechanisms are practical and scalable for implementations. These are all evaluated through a detailed simulator (MATLAB-Simulator) that models long-term and short-term fading impacts. We find the best queue indicator values and then assess different cases where groups have various delay requirements. With the ever increasing number of users and the usage of data in cellular networks, meeting the expectations is a very difficult challenge. To add to the difficulties, the available resources are very limited, so proper management of these resources is very much needed. Scheduling is a key component and having a scheduling scheme which can meet the QoS requirements such as Throughput, Fairness and Delay is importantAbstract -- List of illustrations -- List of tables -- Acknowledgements -- Introduction -- Background -- Scheduler design and related work -- Matlab -- Results and analysis - Reference

Prevalence of insulin induced lipodystrophy in patients with diabetes mellitus in a tertiary care centre: a cross sectional study

Background: Diabetes Mellitus is a spectrum of common metabolic disorders whose management mainly lies in treating the patients with oral hypoglycaemic drugs and insulin along with the dietary and lifestyle modifications. Lipodystrophy is the most neglected adverse drug effect caused by injecting insulin. The main objective of this study was to assess the prevalence of lipodystrophy at the insulin injection sites in patients suffering from diabetes mellitus (Type 1 and Type 2).Methods: A cross-sectional study was conducted in the Department of Endocrinology on 250 diabetic patients taking insulin injections based on inclusion and exclusion criteria. The demographic features and anthropometric measurements were noted. Insulin injection sites were examined clinically by inspection and palpation for presence of swelling like lipodystrophy, injection marks and signs of allergy like erythema etc. Lipodystrophy was graded from 0-3 and denoted as lipohypertrophy or lipoatrophy. The results were tabulated and presented accordingly.Results: In this study, out of 250 patients 17 (6.8%) patients presented with insulin induced lipodystrophy. Lipohypertrophy was the most common presentation and only one case presented with lipoatrophy.Conclusions: It can be concluded from the present study that lipodystrophy which is an important adverse effect due to insulin injection needs to be monitored regularly in every patient taking insulin for better control of glucose levels

Better Patient Privacy Protection with Better Patient Empowerment about Consent in Health Information Exchanges

Since HIPAA laws have permitted broad discretion to Health Information Exchange (HIE) providers, HIEs have configured the patient healthcare consent process to privilege all providers who sign up with the Health Information Exchange with patient health information (PHI) on all consenting patients. This in a sense violates the security principle of “least privilege”. The onus of denying broad based general access for a consenting patient, now resides with the patient. The notion of making the information available to all physicians at all times because they are part of an exchange is not the best practice. Patients empowered with the right information may choose to deny access to their medical records while seeking a second opinion. This research investigates the following questions: How does a more holistic education as opposed to a one-sided message impact patient consent behavior? How does the messaging framework impact the intention to consent under different sharing settings? Utilizing an experimental survey, our results show that the binary setting (share all PHI with all providers) was the least favorable among all participants, while the customized setting was the most favorable

Assessment of knowledge, attitude and practice of insulin injection among subjects with diabetes mellitus

Background: Diabetes mellitus (DM) is a spectrum of common metabolic disorders whose management mainly lies in treating the patients with oral hypoglycemic drugs and insulin along with the dietary and lifestyle modifications. Insulin is administered most subcutaneously. As the insulin injection sites are relatively painless, patients tend to inject in the same area repeatedly rather than moving to a newer site and increase risk for development of injection site reactions like lipodystrophy and impairment of glycemic control. Hence, it is utmost important for every diabetic patient and their relatives who would inject the insulin injection to be aware of appropriate manner of insulin injection. This helps in maintaining adequate glycemic control in diabetic patients. The main objective of this study was to assess the knowledge, attitude and practice of insulin injection technique among the diabetic patients.Methods: A cross-sectional study was conducted in the department of Endocrinology on 250 diabetic patients taking insulin injections based on inclusion and exclusion criteria. A validated questionnaire was administered to patients to answer in order to assess their knowledge, attitude and practice about technique of insulin injection.Results: In this study, it was found that 90% of the patients were aware of rotating the injection site, whereas only 40% of the patients were aware of appropriate time duration (5-10 sec for syringes/counting 1-15 for releasing the pen) required for resting the syringe/pen needle inside the skin. Only 48% of the patients used to remove the air bubble prior to injection, 57% pinched the injection site before injecting, 20% rubbed the injection site after injection and 30% used to wash hands prior to injection. Hypoglycemia was the most common adverse effect noted in 54% of patients.Conclusions: It can be concluded from the present study that every patient and his/her attendant needs to be educated and trained appropriately regarding technique of injecting insulin injection for betterment of their health.