145 research outputs found
Position Control of Ultrasonic Motor Using IMC-PID Combined with Tribes Type NN Algorithm
No full textAbstract. In this paper, we propose a novel scheme of IMC-PID control combined with a tribes type neural network (NN) for the position control of ultrasonic motor (USM). In this method, the NN controller is employed for tuning the parameter in IMC-PID control. The weights of NN are designed to be updated by the tribes-particle swarm optimization (PSO) algorithm. This method makes it possible to compensate for the characteristic changes and nonlinearity of USM. The parameter-free tribes-PSO requires no information about the USM beforehand; hence its application overcomes the problem of Jacobian estimation in the conventional back propagation (BP) method of NN. The effectiveness of the proposed method is confirmed by experiments
Design and Fabrication of Uncooled MEMS Capacitive FPA for IR Imaging
No full textA new structure of MEMS Uncooled capacitive focal plane array (FPA) is presented and its then-no-mechanical behaviors are studied. A surface process with poly-silicon as a sacrificial layer was developed, and in which poly-silicon was dry etched by SF(6) in an ICP system of STS. The etching rates of poly-silicon in lateral and vertical can reach 3.8 and 5.6 mu m/min after the optimization of the process. The process is simple and compatible with most of the IC processes.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000262479800011&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Engineering, Electrical & ElectronicEngineering, MechanicalNanoscience & NanotechnologyEICPCI-S(ISTP)
Process Development of Through-Glass-Via (TGV) Interposer for Radio Frequency (RF) Applications
No full textIn this paper, a simplified process for TGV interposer is presented for RF applications. Sand blasting method and tllinning/polislling process is utilized to form TGVs on Glass wafer. TGV interposer metallization ofis realized witll Al sputtering followed by wet chemical etclling. Based on tlle process, TGV interposer is fabricated and tlle TGV sam pie measures about 36I mu m in tlle diameter at tlle front side, 85 mu m in tlle diameter on tlle back side, and 338 mu m in tlle thickness. Effects of manufacture error due to sand blasting drilling on tlle electrical property of TGV at higll frequency(l-40GHz) is investigated witll simulation results.CPCI-S(ISTP)[email protected]; [email protected]; [email protected]
PID Controller Design of Nonlinear System using a New Modified Particle Swarm Optimization with Time-Varying Constriction Coefficient
No full textThe proportional integral derivative (PID) controllers have been widely used in most process control systems for a long time. However, it is a very important problem how to choose PID parameters, because these parameters give a great influence on the control performance. Especially, it is difficult to tune these parameters for nonlinear systems. In this paper, a new modified particle swarm optimization (PSO) is presented to search for optimal PID parameters for such system. The proposed algorithm is to modify constriction coefficient which is nonlinearly decreased time-varying for improving the final accuracy and the convergence speed of PSO. To validate the control performance of the proposed method, a typical nonlinear system control, a continuous stirred tank reactor (CSTR) process, is illustrated. The results testify that a new modified PSO algorithm can perform well in the nonlinear PID control system design in term of lesser overshoot, rise-time, settling-time, IAE and ISE.
Keywords: PID controller, Particle Swarm Optimization (PSO),constriction factor, nonlinear system
Successful Management of Cervical Esophageal Perforation After Anterior Cervical Surgery
No full textCardiac & Cardiovascular SystemsRespiratory SystemSurgerySCI(E)0LETTER31159-11609
Modified Particle Swarm Optimization using Nonlinear Decreased Inertia Weight
No full textParticle Swarm Optimization (PSO) has demonstrated great performance in various optimization problems. However, PSO has weaknesses, namely premature convergence and easy to get stuck or fall into local optima for complex multimodal problems. One of the causes of these weaknesses is unbalance between exploration and exploitation ability in PSO. This paper proposes a Modified Particle Swarm Optimization (MPSO) using nonlinearly decreased inertia weight called MPSO-NDW to improve the balance. The key idea of the proposed method is to control the period and decreasing rate of exploration-exploitation ability. The investigation with three famous benchmark functions shows that the accuracy, success rate, and convergence speed of the proposed MPSO-NDW is better than the common used PSO with linearly decreased inertia weight or called PSO-LDW
Keywords: particle swarm optimization (PSO), premature convergence, local optima, exploration ability, exploitation ability
Wei zhi she jiao wang luo zhong de xing qu dian tui jian
No full textPh.D.Location-based social networks (LBSNs) have become popular recently because of the explosive increase of smart phones that makes users easily to access to the LBSN Apps. More than 2.3 billion people worldwide use smart phones in 2017 predicted by EMarketer, which prospers the online LBSNs. A typical LBSN such as Foursquare collects users’ check-in information including visited locations’ geographical information (latitude and longitude) and users’ comments at the location and allows users to make friends and share information as well. Driven by the collected big data in LBSNs, point-of-interest (POI) recommendation arises to improve the user experience in the App, which attempts to suggest each user a list of POIs that the user may feel interesting and be willing to visit in the future.Developing POI recommendation systems requires analytics of the human mobility with respect to real-world POIs. Different from watching on Netflix or shopping on Amazon, checking-in at a POI in LBSNs is a physical activity, which causes the most important feature in POI recommendation: geographical influence. In addition, check-ins exhibit specific temporal characteristics. For instance, users check-in at POIs around the office in the day time while at bars in the evening. These geographical and temporal features make the POI recommendation more challenging than traditional recommendation systems.In this thesis, we systematically study the problem of POI recommendation in LBSNs. In particular, we review the literature in the area of POI recommendation, analyze the user mobility in LBSNs, and develop POI recommendation systems. First, we review state-of-the-art POI recommendation techniques and discover the challenges in POI recommendation systems. Second, we analyze the user mobility in LBSNs from geographical and temporal perspective respectively and show how to capture the geographical and temporal influence in a POI recommendation system. Third, we develop two POI recommendation systems: Geo-Teaser and STELLAR. Finally, we conclude this thesis and point out future work directions.最近基於位置的社交網絡（LBSN）由於智能手機的爆炸式增長而變得流行起來。由EMarketer 預測，在2017 年全球超過23 億人使用智能手機，這使得用户可以輕鬆訪問手機應用程序而普及了基於位置的社交網絡。Foursquare 等典型的基於位置的社交網絡會收集用户的簽到信息，包括訪問地點的地理位置信息（緯度和經度）以及用户在該位置的評論，并允許用户交朋友和共享信息。在位置社交網絡收集到的大數據的驅動下，興趣點（POI）推薦應用應運而生以改善位置社交網絡應用中的用户體驗。興趣點推薦應用旨在向每個用户建議用户可能感興趣并願意在將來訪問的興趣點列表。開發興趣點推薦系統需要對現實世界的興趣點進行人員移動性的分析。不同於在Netflix 上觀影或在亞馬遜購物，在位置社交網絡中的興趣點進行簽到是一種親身體驗行为，這形成了興趣點推薦中最重要的特徵：地理影響。另外，簽到行为也表現出特别的時間特徵。例如，用户在白天常在辦公室附近的興趣點簽到, 而在晚上則是在酒吧活動。這些地理和時間特徵使興趣點推薦比傳統的推薦系統更具挑戰性。在本論文中，我們系統的研究了位置社交網絡中的興趣點推薦問題。具體的，我們回顧了興趣點推薦領域的文獻，分析了位置社交網絡中的用户移動性，并提出了原創的興趣點推薦系統。首先，我們綜述了主流的興趣點推薦技術，并分析興趣點推薦系統存在的挑戰。第二，我們分别從地理和時間角度分析位置社交網絡中的用户移動性，并展示如何在興趣點推薦系統中利用地理和時間影響提高系統表現。第三，我們開發了兩個興趣點推薦系統：Geo-Teaser 和STELLAR。最後，我們總結本論文并指出未來的工作方向。Zhao, Shenglin.Thesis Ph.D. Chinese University of Hong Kong 2018.Includes bibliographical references (leaves 147-167).Abstracts also in Chinese.Title from PDF title page (viewed on 25, May, 2021).Zhao, Shenglin
Applications of ultrasonic sensors and obrid-sensor in safety confirmation system for elders
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