• Title/Summary/Keyword: one-time property

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Two-Degree-of Freedom Control of the Synchronous Generator Using $H_{\infty}$ Control Methods ($H_{\infty}$ 제어이론을 사용한 동기 발전기의 2-자유도 제어)

  • Kim, Young-Su;Kim, Tae-Joon;Lee, Byung-Ha
    • Proceedings of the KIEE Conference
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    • 1998.07b
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    • pp.754-756
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    • 1998
  • In this paper the control methods for the synchronous generator is designed based on the two-degree-of-freedom (TDOF) control methods which can safisty the command following property and Robust control property at the same time. The power systems is reduced to one machine infinite-bus system. Robust stability of the proposed power system stabilizer is checked through the simulation considering the circumstance which can happen in real situation.

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Design Sensitivity in Quasi-One-Dimensional Silicon-Based Photonic Crystalline Waveguides

  • Kinoshita, Takeshi;Shimizu, Akira;Iida, Yukio;Omura, Yasuhisa
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.3 no.1
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    • pp.55-61
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    • 2003
  • This paper describes how the optical properties of a quasi-one-dimensional photonic crystalline waveguide having a periodic air cavity are influenced by various structural parameters; the electromagnetic fields are simulated using the finite-difference time-domain method. The simulations considered four design parameters: cavity size, defect size, lattice constant, and number of cavity. The parameter sensitivity of the photonic bandgap property of the waveguide having air cavities is examined. A couple of significant design guidelines are obtained. We show that the quasi-one-dimensional photonic crystalline waveguide has significant unrealized potential.

Context Prediction Using Right and Wrong Patterns to Improve Sequential Matching Performance for More Accurate Dynamic Context-Aware Recommendation (보다 정확한 동적 상황인식 추천을 위해 정확 및 오류 패턴을 활용하여 순차적 매칭 성능이 개선된 상황 예측 방법)

  • Kwon, Oh-Byung
    • Asia pacific journal of information systems
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    • v.19 no.3
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    • pp.51-67
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    • 2009
  • Developing an agile recommender system for nomadic users has been regarded as a promising application in mobile and ubiquitous settings. To increase the quality of personalized recommendation in terms of accuracy and elapsed time, estimating future context of the user in a correct way is highly crucial. Traditionally, time series analysis and Makovian process have been adopted for such forecasting. However, these methods are not adequate in predicting context data, only because most of context data are represented as nominal scale. To resolve these limitations, the alignment-prediction algorithm has been suggested for context prediction, especially for future context from the low-level context. Recently, an ontological approach has been proposed for guided context prediction without context history. However, due to variety of context information, acquiring sufficient context prediction knowledge a priori is not easy in most of service domains. Hence, the purpose of this paper is to propose a novel context prediction methodology, which does not require a priori knowledge, and to increase accuracy and decrease elapsed time for service response. To do so, we have newly developed pattern-based context prediction approach. First of ail, a set of individual rules is derived from each context attribute using context history. Then a pattern consisted of results from reasoning individual rules, is developed for pattern learning. If at least one context property matches, say R, then regard the pattern as right. If the pattern is new, add right pattern, set the value of mismatched properties = 0, freq = 1 and w(R, 1). Otherwise, increase the frequency of the matched right pattern by 1 and then set w(R,freq). After finishing training, if the frequency is greater than a threshold value, then save the right pattern in knowledge base. On the other hand, if at least one context property matches, say W, then regard the pattern as wrong. If the pattern is new, modify the result into wrong answer, add right pattern, and set frequency to 1 and w(W, 1). Or, increase the matched wrong pattern's frequency by 1 and then set w(W, freq). After finishing training, if the frequency value is greater than a threshold level, then save the wrong pattern on the knowledge basis. Then, context prediction is performed with combinatorial rules as follows: first, identify current context. Second, find matched patterns from right patterns. If there is no pattern matched, then find a matching pattern from wrong patterns. If a matching pattern is not found, then choose one context property whose predictability is higher than that of any other properties. To show the feasibility of the methodology proposed in this paper, we collected actual context history from the travelers who had visited the largest amusement park in Korea. As a result, 400 context records were collected in 2009. Then we randomly selected 70% of the records as training data. The rest were selected as testing data. To examine the performance of the methodology, prediction accuracy and elapsed time were chosen as measures. We compared the performance with case-based reasoning and voting methods. Through a simulation test, we conclude that our methodology is clearly better than CBR and voting methods in terms of accuracy and elapsed time. This shows that the methodology is relatively valid and scalable. As a second round of the experiment, we compared a full model to a partial model. A full model indicates that right and wrong patterns are used for reasoning the future context. On the other hand, a partial model means that the reasoning is performed only with right patterns, which is generally adopted in the legacy alignment-prediction method. It turned out that a full model is better than a partial model in terms of the accuracy while partial model is better when considering elapsed time. As a last experiment, we took into our consideration potential privacy problems that might arise among the users. To mediate such concern, we excluded such context properties as date of tour and user profiles such as gender and age. The outcome shows that preserving privacy is endurable. Contributions of this paper are as follows: First, academically, we have improved sequential matching methods to predict accuracy and service time by considering individual rules of each context property and learning from wrong patterns. Second, the proposed method is found to be quite effective for privacy preserving applications, which are frequently required by B2C context-aware services; the privacy preserving system applying the proposed method successfully can also decrease elapsed time. Hence, the method is very practical in establishing privacy preserving context-aware services. Our future research issues taking into account some limitations in this paper can be summarized as follows. First, user acceptance or usability will be tested with actual users in order to prove the value of the prototype system. Second, we will apply the proposed method to more general application domains as this paper focused on tourism in amusement park.

A Study on The Types and Traits of Conversion Design Methods of Modern Architecture for Renewal Use in Japan (일본에서의 근대건축물의 재생과 활용을 위한 킨버전디자인 수법의 유형과 특성에 관한 연구)

  • Lo, Jung-Eun;Park, Chan-Il
    • Korean Institute of Interior Design Journal
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    • v.16 no.2 s.61
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    • pp.40-50
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    • 2007
  • This study started from my concern over maintenance and renewal of existing buildings and other seriously damaged Modern Architecture under the urban development. Above all, we must face up to reality of an increasing need of renovation of old buildings that are in its physical, social, and economical decrepitude. Currently, 25% of total buildings come under renovation period within 20 years, which means that we do not have enough time to decide the destiny of old buildings. In the city, there has been endless controversy over conversation and development. Recently the Cultural property Registration System made it possible a positive usage of non-designated cultural property with historical value. This very useful system renewed our perception on Modern Architecture as cultural property and also triggered peoples' interest in recreating new value beyond economical one. So we really need a balanced view that can bring into both growth of contemporary city and renewal use of Modern Architecture. Here, in this study I tried to solve that problem with Conversion Design and define what a realistic design way for them is. To get more reasonable result, I chose a factor analysis for 20 conversion projects in Japanese Modern Architecture. Conversion Design is a proper way to restore the identity of old buildings and the most effective way to sustainable use of Modern Architecture.

Development and Mass Production Potential of a Novel 5-side Photodiode LED Viewing Angle Measurement System (5면 Photodiode를 이용한 양산 공정용 LED 지향각 측정 시스템개발에 관한 연구)

  • Kim, Dee-Wan;Park, Chan-Hee;Kim, Keun-Sik;Kim, Cheol-Sang
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.20 no.5
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    • pp.623-631
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    • 2011
  • Light emitting diodes (LEDs) which can produce uniform luminescence need a very difficult and complex procedure because LEDs have strong and straight optical property. One of the major parameters for LED production is the determination of the viewing angle. However, in the present, there is still no available production technology to measure LED viewing angle and optical property. In this study, we developed a five-side LED viewing angle and optical property measurement system, having a source meter that uses a high speed switching photo relay instead of a mercury relay. This new measurement system can measure the viewing angle at a very high accuracy of ${\pm}0.66^{\circ}$. This new technology presents a great potential for fast and reliable LED mass production, which can significantly cut down the cost from savings in production time.

A study on the surface change of MgO by discharge in AC PDP (방전시간에 따른 MgO 표면층의 변화에 관한 연구)

  • Ji, S.W.;Yeo, J.Y.;Kim, D.H.;Park, C.H.;Cho, J.S.
    • Proceedings of the KIEE Conference
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    • 1998.07e
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    • pp.1764-1766
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    • 1998
  • One of the most important problems in the development of AC PDP is to make long life and more stable panels. It is well known that the life time of a panel strongly depends on the sputtering-resistant property of the protecting layer such as MgO. However, the sputtering rate is so low that it is very difficult to measure the sputtering-resistant property of MgO. This paper describes a high speed measurement technique to test the sputtering-resistant property of MgO thin film by the R.F. magnetron sputtering. In this case the MgO sample has been used as a target of sputtering process. Moreover, the MgO surface changed by ion-bombarding sputtering are also discussed with SEM photoes.

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Scientometrics Profile of Global Intellectual Property Rights Research

  • Gnanasekaran, D.;Balamurugan, S.
    • Journal of Information Science Theory and Practice
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    • v.4 no.2
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    • pp.53-65
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    • 2016
  • The authors in this paper aim to identify the growth of literature on Intellectual Property Rights (IPRs). The research publications on IPRs were downloaded from the Scopus online citation database and the authors found that there were 1,513,138 records contributed globally over a period of 10 years from 2005 to 2014. The distribution of publications based on the year, country, and document type were studied. Relative growth rate (RGR) of the publications and doubling time (Td) were calculated. Most productive organizations, source titles, and the productive authors on IPR research were studied. Most cited articles in the study area were identified. The results show that a number of publications under the subjects Medicine and Engineering were produced. The developed countries are very active in IPR research and producing publications. It is found that one institution which holds the sixth place among the top 10 most productive institutions belongs to Brazil, a developing country. Two developing countries such as China and India hold second and tenth positions respectively in the top 10 countries contributing literature on IPRs.

Estimation of Representative Mechanical Property of Porous Electrode for Secondary Batteries with Homogenization Method (균질화 기법을 이용하여 기공이 있는 이차전지 극판의 대표 기계 물성 도출을 위한 연구)

  • Pyo, Changmin;Kim, Jaewoong
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.21 no.9
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    • pp.85-91
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    • 2022
  • The demand for electric vehicles has increased because of environmental regulations. The lithium-ion battery, the most widely used type of battery in electric vehicles, is composed of a cathode, an anode, and an electrolyte. It is manufactured according to the pole plate, assembly, and formation processes. To improve battery performance and increase manufacturing efficiency, the manufacturing process must be optimized. To do so, simulation can be used to reduce wasted resources and time, and a finite-element method can be utilized. For high simulation quality, it is essential to reflect the material properties of the electrode by considering the pores. However, the material properties of electrodes are difficult to derive through measurement. In this study, the representative volume element method, which is a homogenization method, was applied to estimate the representative material properties of the electrode considering the pores. The representative volume element method assumes that the strain energy before and after the conversion into a representative volume is conserved. The method can be converted into one representative property, even when nonhomogeneous materials are mixed in a unit volume. In this study, the material properties of the electrode considering the pores were derived. The results should be helpful in optimizing the electrode manufacturing process and related element technologies.

A Study on Electric Property of BLT thin films as a function of the Post Annealing Time (열처리 시간에 따른 BLT 박막의 전기적 특성에 관한 연구)

  • Kim, Eung-Kwon;Kim, Hyun-Duk;Choi, Jang-Hyun;Kim, Hong-Joo;Song, Joon-Tae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07b
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    • pp.574-577
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    • 2002
  • In recent year, BLT$(Bi_{3.25}La_{0.75}Ti_3O_{12})$ has been one of promising substitute materials at the ferroelectric random access memory applications. We manufactured $(Bi_{3.25}La_{0.75}Ti_3O_{12})$ Target with a ceramic process. The BLT target was sintered at $1100^{\circ}C$ for 4 hours. Using RF magnetron sputtering, a deposited BLT thin films were estimated about ferroelectric property as a functions of post annealing time. The BLT thin films showed a promoted ferroelectric characteristics at the post annealied sample for 30 minutes. This sample exhibited the (117) preferred crystal orientation, current density of $2{\times}10^{-8}A/cm^2$, a remanent polarization of $10{\mu}C/cm^2$ and a coercive field of 62.1 KV/cm respectively.

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Changes in Pasting and Fluid Properties of Corn and Rice Starches after Physical Modification by Planetary Mill

  • Kim, Bum-Keun;Lee, Jun-Soo;Cho, Yong-Jin;Park, Dong-June
    • Food Science and Biotechnology
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    • v.17 no.4
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    • pp.814-818
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    • 2008
  • Com and rice starches were physically modified by planetary mill. While native starches showed high peak viscosities (1,001 and 563 cp), it decreased largely (42 and 20 cp for rice and com starch, respectively) after 2 hr of physical modification. When two starches were co-ground, peak viscosities decreased more largely than single ground one only in 30 min, indicating the pasting properties could be easily changed by co-grinding. Especially, the higher the amount of com starch, the viscosity decreased more largely, which means that paste stability could be controlled also by changing the ratio of com and rice starch. Mean particle size increased with physical modification time since particles became spread because of shear force. There were also changes in surface morphology after physical modification. Fluid property, such as mean time to avalanche (MTA), was improved (from $6.16{\pm}0.47$ and $8.37{\pm}1.23\;sec$ to $5.47{\pm}0.78$ and $5.26{\pm}1.37\;sec$ for rice and com starch, respectively) by physical modification. Pasting property, such as swelling power, was also improved by physical modification. These mean that native starches can be applied to both conventional powder and new paste-food industry more efficiently by physical modification.