Browsing by Author "Lai, Yi-Sheng"

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A Novel Search Scheme for Nonintrusive Load Monitoring Systems
(2012)
Lai, Yi-Sheng
;
Chen, Yung-Chi
;
Tsao, Shiao-Li
;
Tsai, Tzung-Cheng
;
資訊工程學系
A nonintrusive load monitoring (NILM) system analyzes the changes of voltage and current on an electrical circuit and can disaggregate the usage and power consumption of appliances on the same circuit loop according to different power consumption signatures of the appliances. An NILM system is regarded as one of the most important features for energy monitoring and management in a smart home and building. Advances in computing, communication and storage technologies further make an NILM system possible to accommodate a huge amount of power consumption signatures of appliances, and to detect appliances and/or appliance states through database search techniques. In this study, we propose a low-cost NILM system for a smart home and building to facilitate end users contributing the power consumption signatures of their appliances to a datacenter through confirmations or feedbacks of the NILM search. Based on those user contributed datasets, a new NILM search algorithm is then presented in this paper. To evaluate and compare the performance and accuracy of NILM search results by employing the proposed and existing approaches, an evaluation test-bed is established. The experimental results demonstrate that the proposed scheme outperforms the existing algorithms and can achieve 85% to 96% accuracy of appliance state detections.
Characteristics of low-temperature pulse-laser-deposited (Pb,Sr)TiO3 films in metal/ferroelectric/silicon structure
(2007-01-07)
Wang, Jyh-Liang
;
Lai, Yi-Sheng
;
Lee, Trent Gwo-Yann
;
Chiou, Bi-Shiou
;
Tsai, Chun-Chien
In this study, pulsed- laser deposited ( Pb, Sr) TiO3 ( PSrT) films on p- type Si were studied at low substrate temperatures ranging from 300 to 450 degrees C for metal/ ferroelectric/ semiconductor applications. The substrate temperature strongly enhances film crystallinity without significant inter- diffusion at the PSrT/ Si interface and affects the electrical properties. As the substrate temperature increases, the films have smaller leakage currents, fewer trap states at the electrode interfaces, clockwise capacitance versus applied field hysteresis loops and larger memory windows correlated with superior crystallinity. Conversely, 300 degrees C- deposited films exhibit a small and counterclockwise loop with a positive shift of the flatband voltage, attributed to more negative trap charges within the films. However, the high substrate temperature ( 450 degrees C) may produce serious Pb - O volatilization, incurring more defects and leakage degradation. The analyses of fixed charge density and flatband voltage shift reveal the trap status and agree well with the leakage characteristic. An electron band model of the Pt/ PSrT/ Si electronic structure is proposed to explain the electrical behaviour. The excellent fatigue endurance with a small variation of memory windows (< 11%) after 1010 switching is also demonstrated.
Dependence of ferroelectric characteristics on the deposition temperature of (Pb,Sr)TiO3 films
(2007-10-01)
Wang, Jyh-Liang
;
Lai, Yi-Sheng
;
Shye, Der-Chi
;
Chou, Chen-Chia
;
Chiou, Bi-Shiou
The pulsed laser deposition (PLD) of (Pb,Sr)TiO3 (PSrT) films on Pt/SiO2/Si at low substrate temperatures (T-s, ranging from 300 to 450 degrees C, has been investigated. The PLD PSrT films prepared at low Ts exhibit ferroelectric proper-ties, good crystallinity, and no significant interdiffusion between the PSrT film and the Pt bottom electrode. The conduction mechanism is identified as Schottky emission at low electric fields and as Poole-Frenkel emission at high electric fields. PSrT films grown at appropriate T, yield fewer interface states and fewer trapping states, leading to a smaller leakage current. The enhanced (100) preferred orientation of PSrT films deposited at T-s= 350-400 degrees C exhibits optimum ferroelectricity. In addition, the dielectric constant and ferroelectricity are associated with the preferred orientation. This shows that the electrical characteristics strongly rely on the preferred orientation and trapping states, which could be controlled by varying the substrate temperature (T, <= 450 degrees C during PLD.
Effects of accumulated laser pulses on (Pb,Sr)TiO(3) films post-excimer laser annealed at low temperatures
(2007-08-01)
Wang, Jyh-Liang
;
Lai, Yi-Sheng
;
Chiou, Bi-Shiou
;
Shye, Der-Chi
;
Hwang, Chuan-Chou
In this article, we report the effect of excimer laser annealing (ELA) on the characteristics of (Pb,Sr)TiO(3) (PSrT) films. The unirradiated and irradiated films are characterized by atomic force microscope (AFM), X-ray photoelectron spectroscopy, X-ray diffractometer (XRD), transmission electron microscopy (TEM), and electron energy loss spectroscopy (EELS). It is found that the crystallinity is improved and the oxygen content is increased by ELA. Besides, the surface morphology becomes rough after ELA. Moreover, PSrT films irradiated by ELA are found to increase the grain size near the surface. The material properties of unirradiated and irradiated films, as well as the characteristics of PSrT films irradiated with various laser pulses, will be explored in this study. (c) 2007 Elsevier B.V. All rights reserved.
Effects of accumulated laser pulses on (Pb,Sr)TiO3 films post-excimer laser annealed at low temperatures
(2007-08-01)
Wang, Jyh-Liang
;
Lai, Yi-Sheng
;
Chiou, Bi-Shiou
;
Shye, Der-Chi
;
Hwang, Chuan-Chou
In this article, we report the effect of excimer laser annealing (ELA) on the characteristics of (Pb,Sr)TiO3 (PSrT) films. The unirradiated and irradiated films are characterized by atomic force microscope (AFM), X-ray photoelectron spectroscopy, X-ray diffractometer (XRD), transmission electron microscopy (TEM), and electron energy loss spectroscopy (EELS). It is found that the crystallinity is improved and the oxygen content is increased by ELA. Besides, the surface morphology becomes rough after ELA. Moreover, PSrT films irradiated by ELA are found to increase the grain size near the surface. The material properties of unirradiated and irradiated films, as well as the characteristics of PSrT films irradiated with various laser pulses, will be explored in this study. (c) 2007 Elsevier B.V. All rights reserved.
Ferroelectricity and negative temperature coefficient of resistance in pulsed-laser-deposited (Pb, Sr) TiO(3) films
(2008-04-21)
Wang, Jyh-Liang
;
Lai, Yi-Sheng
;
Liou, Sz-Chian
;
Tsai, Chun-Chien
;
Chiou, Bi-Shiou
(Pb, Sr)TiO(3) films deposited on Pt/SiO(2)/Si substrates by pulsed-laser deposition (PLD) at 400 degrees C with oxygen pressures ranging from 50 to 200 mTorr have been investigated. The paraelectricity-to-ferroelectricity transition of films depends on the oxygen pressure during deposition. Films deposited at 200 mTorr exhibit paraelectric-like nature, whereas films deposited at lower pressures present the ferroelectric characteristic. The (Pb, Sr) TiO(3) film is found to exhibit a negative temperature coefficient of resistance (NTCR) at the measurement temperature ranging from 30 to 390 degrees C. This work demonstrates that the ferroelectricity/paraelectricity and the temperature coefficient of resistance of (Pb, Sr) TiO(3) films could be controlled by oxygen pressures during PLD.
Method and system for detecting an appliance based on users' feedback information
(2013-05-22)
Tsao, Shiao-Li
;
Lai, Yi-Sheng
A method and system for detecting an appliance based on users' feedback information, particularly a nonintrusive load monitoring method and system based on a user's feedback information and a joint strategic decision search algorithm are disclosed. By means of obtaining the users' feedback information on an appliance inputted by users or a search result of the appliances being confirmed by the users to generate a mapping between the model of the appliances and at least one load signature of each model of appliances; the users' feedback information is recorded into a smart meter or a cloud computing system, and a mathematical analysis is further used to compute an occurrence of any one signature of the appliance and the identification rate of each signature; then the joint strategic decision search algorithm automatically identifies various models of appliances and analyzes the operating states of the electric appliances in homes or offices.
Polarization degradation and breakdown of pulse-laser-deposited (Pb,Sr)TiO3 films at low temperatures
(2007-01-01)
Wang, Jyh-Liang
;
Shye, Der-Chi
;
Lai, Yi-Sheng
;
Tseng, Huai-Yuan
;
Juan, Chuan-Ping
(Pb,Sr)TiO3 (PST) films were deposited on Pt/SiO2/Si by pulsed laser deposition at low substrate temperatures (T-s) ranging from 300 to 450 degrees C. The loss in remnant polarization (P-r) and coercive field (E-c) is found to be less than 17% after 10(10) switching cycles when T-s is higher than 350 degrees C. It is also suggested that the leakage current is reduced when T-s increases up to a temperature of 400 degrees C. However, PST films deposited at 450 degrees C may produce serious Pb-O volatilization, resulting in the deterioration of the crystallinity and high leakage currents. As a result, the 400 degrees C-deposited PST film reveals the lowest leakage current, nearly fatigued-free J-E characteristics after 10(10) switching cycles, and the best breakdown property, attributed to the enhanced crystallinity and low concentration of defects.
Power monitoring device for identifying state of electric appliance and power monitoring method thereof
(2012-01-04)
Tsao, Shiao-Li
;
Lai, Yi-Sheng
;
Lin, Ming-Chun
;
Chen, Yung-Chi
A power monitoring device for identifying the state of an electric appliance based on user feedbacks and a power monitoring method thereof are provided. The power monitoring device includes a measurement module, a variation detection and search module, and an electric appliance signature database established based on user feedbacks. When the measurement module detects a variation of a power consumption feature, the variation detection and search module searches the electric appliance signature database according to the variation to obtain electric appliances similar to the variation and the states thereof. A user contributes data to the electric appliance signature database by confirming the search result, or selecting the correct electric appliance and the state thereof. When the user confirms the search result, the power monitoring device establishes an association between the electric appliance and its electric appliance signatures and updates the electric appliance signature database.
Structural and electrical investigation of laser annealed (Pb,Sr)TiO3 thin films
(2008-01-01)
Wang, Jyh-Liang
;
Lai, Yi-Sheng
;
Liou, Sz-Chian
;
Chiou, Bi-Shiou
;
Jan, Chueh-Kuei
Material and electrical characteristics of (Pb,Sr)TiO3 (PSrT) films irradiated by various laser pulses and laser fluences are investigated in this work. Enhanced crystallinity can be obtained after excimer laser annealing (ELA). However, grain growth induced by ELA is nonuniform, and the effect is limited to the upper region of the films. As the number of laser pulses increases to 120, the film shows stronger diffraction intensities and increased oxygen content, resulting in a distinct capacitance versus electric field hysteresis loop and a larger dielectric constant than the nonirradiated one. The leakage current is found to be associated with the interface quality. The conduction mechanism of nonirradiated and irradiated PSrT films is mainly governed by Schottky emission at low electric fields, whereas the Poole-Frenkel emission occurs for films irradiated with more than 120 laser pulses or laser fluences larger than 90.5 mJ/cm(2) at high electric fields. (C) 2008 American Vacuum Society.
Structural and electrical investigations of pulse-laser-deposited (Pb,Sr)TiO3 films at various oxygen partial pressures
(2007)
Wang, Jyh-Liang
;
Lai, Yi-Sheng
;
Liou, Sz-Chian
;
Chou, Chen-Chia
;
Tsai, Chun-Chien
Pulsed-laser deposited (Pb,Sr)TiO3 (PSrT) films on Pt/SiO2/Si substrate deposited at various oxygen partial pressures (P-O2), ranging from 50 to 200 mTorr, were investigated in this work. PSrT films exhibit (100) preferred orientation at lower P-O2 and then transit to (110) preferred orientation above 100 mTorr. The paraelectricity/ferroelectricity transition and dielectric constant of PSrT films are associated with the preferred orientation and oxygen concentration at various P-O2. Furthermore, films deposited at higher P-O2 exhibit higher breakdown field and smaller leakage current density as a consequence of fewer oxygen vacancies. Except for the case of films deposited at 200 mTorr, the conduction mechanism is identified as Schottky emission/Poole-Frenkel emission at low/high electric fields. (c) 2007 The Electrochemical Society.
Study on fatigue and breakdown properties of Pt/(Pb,Sr)TiO3/Pt capacitors
(2006-11-22)
Wang, Jyh-Liang
;
Lai, Yi-Sheng
;
Chiou, Bi-Shiou
;
Tseng, Huai-Yuan
;
Tsai, Chun-Chien
Pulsed- laser deposited ( Pb, Sr) TiO3 ( PSrT) films on Pt/ SiO2/ Si substrate at various ambient oxygen pressures ( P-O2) are investigated in this work. Films deposited at P-O2 below 100 mTorr exhibit the ( 100) preferred orientation and a tetragonal structure with larger tetragonality. In addition, films deposited at 80 mTorr exhibit the most apparent ferroelectric properties in contrast to those deposited at 200 mTorr. Moreover, films deposited at higher P-O2 also exhibit longer lifetimes and higher breakdown fields due to their smaller leakage current density, in terms of the reduction of defects, compensation of oxygen vacancies (OVs), an improved interface and small cluster sizes. An energy band model reveals that fatigue properties of PSrT films are dominated by interfacial states at low P-O2 and by deep trapping states at high P-O2, which could be ascribed to OVs located at the interfaces and inside films, respectively.
Tailoring of amorphous SiOx nanowires grown by rapid thermal annealing
(2008-02-20)
Lai, Yi-Sheng
;
Wang, Jyh-Liang
;
Liou, Sz-Chian
;
Tu, Chia-Hsun
;
電子工程學系及電子研究所
The growth of Pt-catalyzed SiOx nanowires by rapid thermal annealing at 900 degrees C is demonstrated in the study. The growth of the nanowire is found to occur via a catalyst driven VLS mechanism. The seed particle composed of Pt-Si alloy is observed from the reaction between SiO2 and the catalytic Pt film. When the annealing time exceeds 60 s, the SiOx nanowires first agglomerate, and then collapse to form dendritic islands on the surface. The dendritic islands may result from the reaction between Pt-Si seed particle and SiOx nanowires, and are identified to be the Pt-Si compound. (C) 2008 Elsevier B.V. All rights reserved.
Temperature-dependent characteristics of pulse-laser-deposited (Pb,Sr)TiO3 films at low temperatures
(2008-01-01)
Wang, Jyh-Liang
;
Lai, Yi-Sheng
;
Chiou, Bi-Shiou
;
Chou, Chen-Chia
;
Lee, Trent Gwo-Yann
Pulsed laser deposition (PLD) of (Pb,Sr)TiO3 (PSrT) film on Pt/SiO2/Si at low substrate temperatures (T-s), ranging from 300-450 degrees C, has been investigated. As T-s increases, the films reveal coarsening clusters, improved crystallization of the perovskite phase, distinct capacitance-electric field (C-E) hysteretic loops and a larger dielectric constant. The 350 degrees C-deposited film shows strong (100) preferred orientation and optimum dielectric properties with the dielectric constant of similar to 620. The current density increases as the measurement temperature and the electric field increase. Moreover, PSrT films exhibit a strong negative temperature coefficient of resistance (NTCR) behavior at temperatures ranging from 100 to 390 degrees C.