An Automated System for ST Segment and Arrhythmia Analysis in Exercise Radionuclide Ventriculography

A computer-based system for interpretation of the electrocardiogram (ECG) in the diagnosis of arrhythmia and ST segment abnormality in an exercise system is presented. The system was designed for inclusion in a gamma camera so that ECG diagnosis could be combined with the diagnostic capability of radionuclide ventriculography. Digitized data are analyzed in a beat-by-beat mode and a contextual diagnosis of underlying rhythm is provided. Each beat is assigned a beat code based on a combination of waveform analysis and RR interval measurement. The waveform analysis employs a new correlation coefficient formula which corrects for baseline wander. Selective signal averaging, in which only normal beats are included, is done for an improved signal-to-noise ratio prior to ST segment analysis. Template generation, R wave detection, QRS window size, baseline correction, and continuous updating of heart rate have all been automated. ST level and slope measurements are computed on signal-averaged data. Arrhythmia analysis of 13 passages of abnormal rhythm by computer was found to be correct in 98.4 percent of all beats. 25 passages of exercise data, 1-5 min in length, were evaluated by the cardiologist and found to be in agreement in 95.8 percent in measurements of ST level and 91.7 percent in measurements of ST slope.     

Joint trajectory generation for redundant robots in an environment with obstacles

Collision avoidance is an absolutely essential requirement for a robot to complete a task in an environment with obstacles. For kinematically redundant robots, collision avoidance can be achieved by making full use of the redundancy. In this article, the problem of determining collision-free joint space trajectories for redundant robots in an environment with multiple obstacles is considered, and the “command generator” approach is employed to generate such trajectories. In this approach, a nondifferentiable distance objective function is defined and is guaranteed to increase wherever possible along the trajectory through a vector in N(J), the null space of Jacobian matrix J. Algorithms that implement this nondifferentiable optimization problem are fully developed. It is shown that the proposed collision-free trajectory generation scheme is efficient and practical. Extensive simulation results of a four-link robot example are presented and analyzed.     

On sampled data approach to parameter identification of continuous linear systems

It is generally preferable to estimate unknown parameters in analog transfer functions by sampled data techniques. This approach calls for the derivation of an appropriate discrete modelD(z)for a given analog systemH(s)with undetermined parameters, and then the fitting of the sampled input-output data byD(z)to estimate these parameters. This correspondence presents a method for obtaining such discrete models. It also provides a more effective procedure for calculating the parameter estimates from the identified discrete transfer functionhat{D}(z).     

Partial nitrification of ammonium-rich wastewater as pretreatment for anaerobic ammonium oxidation (Anammox) using membrane aeration bioreactor

A lab-scale membrane aeration bioreactor (MBR) system was developed for treating synthetic ammonium-rich wastewater to yield an appropriate NO(2)(-)/NH(4)(+) mixture as a pretreatment for anaerobic ammonium oxidation (Anammox). The effluent with a suitable NO(2)(-)/NH(4)(+) ratio (1:1 to 1:1.3) was obtained in 24 h using the developed MBR system under suitable conditions. Additionally, the control of bulk dissolved oxygen (DO) level under a desired condition (anoxic condition) was easier and more economical than traditional aeration systems. An optimal initial alkalinity of 1500 mg CaCO(3)l(-1) was necessary for achieving 50% partial nitrification of wastewater with an initial ammonium concentration of 510 mg NH(4)-N l(-1) within 24 h. Furthermore, there is no need for pH adjustment by adding a base or an acid throughout the reaction if the initial alkalinity is appropriately controlled. Both the appropriate NO(2)(-)/NH(4)(+) ratio and the low DO level make this MBR system an ideal system for Anammox.     

High-performance adaptive group-of-picture rate control for H.264/AVC

In this paper, an adaptive group-of-picture (AGOP) control is proposed to improve the coding performance for the H.264/AVC system. The efficient algorithm is developed to find the quantized parameter with temporal correlation between inter-frames. According to the estimated parameters, the GOP coding type can be adaptively selected as AGOP or BGOP (basic GOP). The rate control with some decision functions is proposed to modify the quantization parameter (QP). The coding rate can accurately meet the target rate with adjusting QP value dynamically, while keeping low computational overhead. Simulation results show that the proposed algorithm can improve PSNR by about 1 dB in average compared with the original H.264/AVC reference software (JM12.4), from various sequences testing.     

安卓应用中无声音频的收集与检测

在安卓系统中，一些安卓应用为了避免被系统杀死，会通过各种方式在后台占用系统的CPU，内存等资源，实现后台保活.这类行为会加速安卓系统的电量消耗.其中一种后台保活的方式是在后台持有Audiomix锁并播放无声音频.针对这种行为，本文设计了相应的方案来检测这个问题.通过对安卓源码进行修改，收集到安卓应用正在播放的音频数据，再通过检测脚本对音频进行实时检测，来判断安卓应用是否在后台播放无声音频来实现保活.实验分析了50个安卓应用，结果表明该方法可以有效检测此类行为.