Software Optimization in Ultrasound Imaging Technique Using Improved Deep Belief Learning Network on the Internet of Medical Things Platform

Wireless Personal Communications - The Internet of Medical Things (IoMT) is the array of medical instruments and related technologies that link Information Technology (IT) systems in...     

一个批判性回顾与展望——台湾大学建筑与城乡研究所教研实践

从理论与专业的角度,回顾过去台湾大学建筑与城乡研究所的教育目标和在知识上的主要发展线索,以及实际执行时遇到的困难。在教育目标上,面对一个发展中国家的教育资源不足的现实,专业的通才教育是核心教师共同的目标,针对建筑、城市规划、地景建筑三者的共享知识,提供规划与设计的专业训练。由于教师职业多为台湾归国留学生中的一时之选,以及发扬开放而自由的台大学风,学生与教师适时地响应了当时台湾社会的变动,这主要表现在对一系列的都市运动的响应之上,取得了一定程度的影响力。面对当前空间与社会的巨变,首先是学生们提出改革的要求,于是教师提出新的因应方向,响应他们的期望,推动机构本身在改革过程所急需的人事、教学与研究的再建构。这是建筑与城乡研究所面对的21世纪的挑战。     

Piecewise empirical model (PEM) of resistive memory for pulsed analog and neuromorphic applications

With the end of Dennard scaling and the ever-increasing need for more efficient, faster computation, resistive switching devices (ReRAM), often referred to as memristors, are a promising candidate for next generation computer hardware. These devices show particular promise for use in an analog neuromorphic computing accelerator as they can be tuned to multiple states and be updated like the weights in neuromorphic algorithms. Modeling a ReRAM-based neuromorphic computing accelerator requires a compact model capable of correctly simulating the small weight update behavior associated with neuromorphic training. These small updates have a nonlinear dependence on the initial state, which has a significant impact on neural network training. Consequently, we propose the piecewise empirical model (PEM), an empirically derived general purpose compact model that can accurately capture the nonlinearity of an arbitrary two-terminal device to match pulse measurements important for neuromorphic computing applications. By defining the state of the device to be proportional to its current, the model parameters can be extracted from a series of voltages pulses that mimic the behavior of a device in an analog neuromorphic computing accelerator. This allows for a general, accurate, and intuitive compact circuit model that is applicable to different resistance-switching device technologies. In this work, we explain the details of the model, implement the model in the circuit simulator Xyce, and give an example of its usage to model a specific \(\hbox {Ta}/\hbox {TaO}_{\mathrm{x}}\) device.     

System performance and economic analysis of solar-assisted cooling/heating system

The long-term system simulation and economic analysis of solar-assisted cooling/heating system (SACH-2) was carried out in order to find an economical design. The solar heat driven ejector cooling system (ECS) is used to provide part of the cooling load to reduce the energy consumption of the air conditioner installed as the base-load cooler. A standard SACH-2 system for cooling load 3.5 kW (1 RT) and daily cooling time 10 h is used for case study. The cooling performance is assumed only in summer seasons from May to October. In winter season from November to April, only heat is supplied. Two installation locations (Taipei and Tainan) were examined.It was found from the cooling performance simulation that in order to save 50% energy of the air conditioner, the required solar collector area is 40 m² in Taipei and 31 m² in Tainan, for COP_j = 0.2. If the solar collector area is designed as 20 m², the solar ejector cooling system will supply about 17–26% cooling load in Taipei in summer season and about 21–27% cooling load in Tainan. Simulation for long-term performance including cooling in summer (May–October) and hot water supply in winter (November–April) was carried out to determine the monthly-average energy savings. The corresponding daily hot water supply (with 40 °C temperature rise of water) for 20 m² solar collector area is 616–858 L/day in Tainan and 304–533 L/day in Taipei.The economic analysis shows that the payback time of SACH-2 decreases with increasing cooling capacity. The payback time is 4.8 years in Tainan and 6.2 years in Taipei when the cooling capacity >10 RT. If the ECS is treated as an additional device used as a protective equipment to avoid overheating of solar collectors and to convert the excess solar heat in summer into cooling to reduce the energy consumption of air conditioner, the payback time is less than 3 years for cooling capacity larger than 3 RT.     

基于FPGA的穆斯堡尔谱仪数据采集卡

FPGA(Field Programmable Gate Array)是一种可编程器件,有着强大的逻辑运算和时序控制能力,尤其擅长于时序信号的采集和处理.基于FPGA的穆斯堡尔谱仪数据采集卡,改变了传统的使用单片机的方法,运算速度明显提高,仪器体积显著减小.通过Quartus Ⅱ开发系统,选用Altera公司Cyclone系列的EP1C6T144C8芯片实现穆斯堡尔谱仪的计数器、存储器及串行通信功能.EP1C6T144C8芯片的逻辑单元为5980个,存储空间为92160位,丰富的逻辑资源可以很好的满足穆斯堡尔谱仪数据采集卡的要求,并且可以实现功能和参数修改.     

A bandwidth enhancement method for microstrip antennas

Bandwidth enhancement methods for electromagnetically coupled microstrip dipoles are discussed. It is demonstrated that if parasitic metallic strips are incorporated in the structure either co-planar and parallel to the embedded microstrip transmission line open end, or between the transmission line and the microstrip dipole, then substantial bandwidth enhancement results. Experimental verification of this model is introduced for a bandwidth definition based on the frequency range which satisfies a voltage standing-wave ratio (VSWR) < 2 criterion. Also, experimentalbar{E}- andbar{H}-plane patterns verify the theoretical model which accounts for radiation from the microstrip dipole, the parasitics, and the transmission line.     

A new technique for robust control of servo systems

The robust controller has very simple structures and can be divided into two separate parts: a servo controller and an auxiliary controller. The two controllers are designed independently. The function of the auxiliary controller is to cancel out the plant uncertainties directly without the use of the high loop gain principle. Interpretation of robot controller as a signal-synthesis adaptive controller is given. Practical implementation issues of the auxiliary controller are discussed. Simulations of a design example with large parameter uncertainty, nonlinearity, and external disturbance are presented to demonstrate the effectiveness of the design technique. This technique is further tested with success in an experimental study of joint position control of a PUMA 560 robot arm     

Slider dynamic motion during writer-induced head-disk contact

The spatial and temporal characteristics of slider motion resulting from writer-induced pole tip protrusion are studied. Head-disc contact results from protrusion and the amount of contact is varied by varying the steady-state write current, the amount of overshoot, and the write frequency, all of which change the amount of heat dissipated in the writer. We measure the resulting slider motion via three orthogonal LDVs and a position sensitive detector to give five of the six possible degrees of freedom of motion. We compare the relative magnitudes of motion in different directions and we explore how higher power gives more continuous contact. We also investigate the time scales associated with protrusion and with air bearing pitch angle changes. We measure the speed with which the writer protrudes and find that slider pitch angle change increases linearly with the amount of current.