70 research outputs found
Dynamic Super Round Based Distributed Task Scheduling for UAV Networks
No full textNetworks of Unmanned Aerial Vehicles (UAVs) are emerging in many application domains, e.g., military surveillance. To perform collaborative tasks, the involved UAVs exchange several types of information, e.g., sensor data and commands. The major question here is how to schedule the tasks under dynamic traffic flows to provide network services. Existing solutions use the Round-Robin Strategy (RRS), where the tasks are scheduled statistically by dividing the time into fixed-length rounds. However, the RRS wastes significant network and device resources due to task scheduling in each round. This paper proposes DROVE – a novel clustering approach that allows the UAVs for dynamic task scheduling. However, determining the task scheduling is crucial, as it significantly affects several network parameters, e.g., throughput. Therefore, we devise the problem of distributed task scheduling under dynamic traffic flow scenarios to optimize the throughput. We propose a clustering task scheduling algorithm to serve dynamic traffic flows. Particularly, we integrate the dynamic traffic flows into the Lyapunov drift analysis framework, and determine the throughput optimality of our proposed scheduling algorithm. We perform extensive simulations to validate the effectiveness of DROVE. The results show that DROVE outperforms the state-of-the-art solutions in terms of energy consumption, clustering overhead, throughput, end-to-end delay, flow success rate and packet drop rate. </p
Probability Reliability and Statistical Methods in Engineering Design
No full textxvi.;ill.;304 hal.; 25 c
Efficient Alternate Test Generation for RF Transceiver Architectures
No full textThe production testing cost of modern wireless communication systems, especially basestation units, is estimated to be as high as 30-40 percent of their manufacturing cost and is increasing with system complexity, high levels of device integration and scaling of CMOS process technology and operating frequencies. The major production testing challenges for RF transceivers are: (a) the high cost of automated test development because of system-level simulation difficulties and the large simulation times involved, (b) the high cost of using high-end, communication protocol-aware RF test instrumentation, and (c) lack of external test access to RF circuits embedded inside integrated transceivers. Consequently, there exists a need for developing efficient design-for-test methodologies and non-invasive system-level test techniques for wireless transceivers to reduce their test cost. This dissertation is focused towards development of new system-level alternate test methodologies for RF transceiver architectures. The research proposes using non-invasive testing techniques for RF subsystems and digital-compatible built-in testing techniques for baseband and intermediate frequency (IF) analog circuits. The objectives of this research are: (a) to develop automatic test stimulus generation algorithms that allow accurate determination of targeted RF system-level test specification values using behavioral modeling and simulation techniques, (b) to develop RF transceiver test techniques that allow testing of embedded RF systems with limited test access, while reducing the test time for complex RF and baseband system-level performance metrics (b) to significantly reduce the test instrumentation overhead for testing complex frequency-domain and modulation-domain system specifications. The feasibility and the cost benefits of using the proposed alternate test approaches have been demonstrated using 900 MHz and 1575 MHz transceiver prototypes.Ph.D
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No full textThe Ca2+-sensor synaptotagmin-1 that triggers neuronal exocytosis binds to negatively charged membrane lipids (mainly phosphatidylserine (PtdSer) and phosphoinositides (Ptdlns)) but the molecular details of this process are not fully understood. Using quantitative thermodynamic, kinetic and structural methods, we show that synaptotagmin-1 (from Rattus norvegicus and expressed in Escherichia coli) binds to Ptdlns(4,5)P-2 via a polybasic lysine patch in the C2B domain, which may promote the priming or docking of synaptic vesicles. Ca2+ neutralizes the negative charges of the Ca2+-binding sites, resulting in the penetration of synaptotagmin-1 into the membrane, via binding of PtdSer, and an increase in the affinity of the polybasic lysine patch to phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P-2). These Ca2+-induced events decrease the dissociation rate of synaptotagmin-1 membrane binding while the association rate remains unchanged. We conclude that both membrane penetration and the increased residence time of synaptotagmin-1 at the plasma membrane are crucial for triggering exocytotic membrane fusion
An Energy Efficient Oscillator Frequency Calibration Methodology Using Fraction Phase Computation
No full text
Uncertainty modeling in vibration, control and fuzzy analysis of structural systems
No full textThis book gives an overview of the current state of uncertainty modeling in vibration, control, and fuzzy analysis of structural and mechanical systems. It is a coherent compendium written by leading experts and offers the reader a sampling of exciting research areas in several fast-growing branches in this field. Uncertainty modeling and analysis are becoming an integral part of system definition and modeling in many fields. The book consists of ten chapters that report the work of researchers, scientists and engineers on theoretical developments and diversified applications in engineering s
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