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Due to the lack of diversity of the initial population, the multi-objective particle swarm optimization algorithm easily falls into the local optimal value during the iterative process. The method of piecewise logistic chaotic map is introduced to increase the randomness of initial population. A disturbance variable is used to weaken the dependency on global optimal value. A segmented maintenance...
Surface deformation disasters, such as landslides, debris flow and collapse, do great harm to human lives and property. Ground-Based Synthetic aperture radar (GB-SAR) has been widely applied in deformation monitoring and measurement with the advantages of all-weather, all-day and high precision. Back projection (BP) algorithm, algorithm based on keystone and subblock dechirp (KSD), and far-field pseudopolar...
Sedentary behaviors such as sitting and watching TV are ubiquitous in modern societies. Increases in sedentary time have been linked with an increased risk of obesity, diabetes, cardiovascular disease, and all-cause mortality. While smartphones and wearables can now detect sedentary user behaviors, few computational models exist for predicting when they will occur in future. In this paper, we propose...
Sedentary behaviors such as prolonged occupational and leisure-time sitting are now ubiquitous in modern societies. Sedentary time is positively associated with increased risk of obesity, diabetes, cardiovascular disease, and all-cause mortality. Smartphones can sense the sedentary behaviors performed by their users, as well as the contexts (situations) in which sedentary behaviors occur. In this...
Because of the widely dynamic range of ground targets' backscattering coefficients, original GB-SAR image has disadvantage of low contrast ration [1]. In order to enhance contrast, classical method and improved methods based on statistical property of GB-SAR images are studied. Finally, the feasibility and effectiveness of the improved methods are validated with experimental datasets.
For many nonlinear estimation problems, classical lower bounds such as the Cramer-Rao bound (CRB) can characterize the mean squared error (MSE) performance only in the asymptotic region. While more powerful bounds like the Ziv-Zakai bound (ZZB) can also predict the best MSE performance in the nonasymptotic region, they may complicate the computation to an unaffordable extent. In this paper, for estimators...
Cooperative caching and relaying content in ISPs can decrease the bandwidth costs and distribution time. The relay resources installed at ISP are limited and the upload rates of relay servers are various. After formulating the optimization problem, we design a Non-dominated Sorting Bit matrix Genetic Algorithm (NSBGA) to solve it. Constraint-satisfied population is initialized according to resource...
Sedentary lifestyles are ubiquitous in modern societies. Watching television, playing video games, and using the computer while sitting are examples of sedentary behaviors that are now common worldwide. Multiple research studies have found that the length of sedentary time is linked with an increased risk of obesity, diabetes, cardiovascular disease, and all-cause mortality. Medical researchers have...
Sedentary behaviors such as sitting and watching TV increase the risk of many ailments including diabetes, cardiovascular disease and all-cause mortality. Fitness trackers and smartphone apps automatically track users' physical activities and sedentary behaviors to support self-monitoring. These trackers generate activity time-series data that require manual analysis to detect recurrent patterns....
We developed a health and wellness smartphone app to support diabetes self-management. The target users are older, less healthy adults with advanced type 2 diabetes. We illustrate the design implications of a health and wellness smartphone app for such users by presenting the process and results of our usability and user experience lab test with our app.
A design scheme of gas monitoring system based on Zigbee + GPRS is presented in this paper. The gas data is collected from the gas sensor and it uploads to the ARM gateway using WSN technology Zigbee. It can be intelligently control of the local gas valve, exhaust fan, alarm lights and windows through the WSN after data analysis, then it solves the problem caused by the gas in time. At the same time,...
Recognition between true and false ballistic warheads is an important problem in missile defense. In this paper, a multiple-input multiple-output (MIMO) radar with distributed antennas is employed to observe the scene from distinct directions to gain multi-dimensional information of the warheads. A state space model (SSM) is developed to describe the motion behavior of the warheads (state equation)...
Resistive random access memory (RRAM) has been recognized as one of the most promising candidates for next generation non-volatile memory due to its simple structure and excellent scalability. However, poor reliability is a serious issue for RRAM memory applications. To improve the reliability and endurance, many researchers changed the cell material, process and structure. Here, in this paper, we...
In this paper, two different Cramer-Rao bounds are compared for joint target position and velocity estimation for either active or passive radar. The first bound considers the case where the target has been previously detected in a given range cell, so that propagation loss can be estimated. The second bound does not assume the target can be localized to a given range cell. The comparisons are carried...
In order to obtain the maximum power absorption of wave power devices, the mean gain factor q for the array and its characteristics are discussed in this paper. Some characteristics about the maximum q are studied through theoretical derivation and numerical examples. Also, the relationship between the maximum q and the properties of the optimum linear arrays of wave power devices are explored through...
The micro-motion characteristics of warheads have been utilized to discriminate false warheads from true ones. To obtain accurate dimensional measurements, a multiple-input multiple-output (MIMO) radar is adopted to observe the kinetic information of the warhead. A distributed state space model (SSM) is built and the differences between the true and false warheads are characterized as different system...
State estimation of a power grid under undetected power injection attacks is considered. With a known prior probabilistic description of the state variables, the maximum a posteriori probability (MAP) estimator is adopted. Undetected attacks lead to model mismatch, which may greatly degrade the estimation performance. The mean square error (MSE) of the MAP estimate under model mismatch is derived...
The joint target position and velocity estimation performance using an active or passive distributed radar is investigated under more general, and practically occurring, conditions than assumed in previous work. In particular, the presented results allow nonorthogonal signals, spatially dependent Gaussian reflection coefficients, and spatially dependent Gaussian clutter-plus-noise. Given these cases...
The biggest challenge for GEO SAR imaging is to compensate the Doppler parameter space-variance properly. The problem of velocity space-variance becomes severe in GEO SAR due to the effect of earth rotation and large imaging area. In addition, the direction of velocity space-variance is very difficult to determine in Equator due to the very complex geometry relationship among satellite motion, earth...
In this paper, a novel imaging algorithm tailored for GB-SAR data is proposed. The characteristics of GB-SAR data are firstly analyzed, and then a signal model (after range compression) is analytically built up. According to this model, our imaging algorithm, based on keystone formatting and range-Doppler domain subblock division, is then put forward, its azimuth focusing is essentially achieved through...
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