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Lightweight Model for Energy Storage System Remaining Useful Lifetime Estimation (ESS 잔존수명 추정 모델 경량화 연구)

  • Yu, Jung-Un;Park, Sung-Won;Son, Sung-Yong
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.13 no.5
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    • pp.436-442
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    • 2020
  • ESS(energy storage system) has recently become an important power source in various areas due to increased renewable energy resources. The more ESS is used, the less the effective capacity of the ESS. Therefore, it is important to manage the remaining useful lifetime(RUL). RUL can be checked regularly by inspectors, but it is common to be monitored and estimated by an automated monitoring system. The accurate state estimation is important to ESS operator for economical and efficient operation. RUL estimation model usually requires complex mathematical calculations consisting of cycle aging and calendar aging that are caused by the operation frequency and over time, respectively. A lightweight RUL estimation model is required to be embedded in low-performance processors that are installed on ESS. In this paper, a lightweight ESS RUL estimation model is proposed to operate on low-performance micro-processors. The simulation results show less than 1% errors compared to the original RUL model case. In addition, a performance analysis is conducted based on ATmega 328. The results show 76.8 to 78.3 % of computational time reduction.

Speed Control of Marine Gas Turbine Engine using Nonlinear PID Controller (비선형 PID 제어기를 이용한 선박용 가스터빈 엔진의 속도 제어)

  • Lee, Yun-Hyung;So, Myung-Ok
    • Journal of Navigation and Port Research
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    • v.39 no.6
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    • pp.457-463
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    • 2015
  • A gas turbine engine plays an important role as a prime mover that is used in the marine transportation field as well as the space/aviation and power plant fields. However, it has a complicated structure and there is a time delay element in the combustion process. Therefore, an elaborate mathematical model needs to be developed to control a gas turbine engine. In this study, a modeling technique for a gas generator, a PLA actuator, and a metering valve, which are major components of a gas turbine engine, is explained. In addition, sub-models are obtained at several operating points in a steady state based on the trial running data of a gas turbine engine, and a method for controlling the engine speed is proposed by designing an NPID controller for each sub-model. The proposed NPID controller uses three kinds of gains that are implemented with a nonlinear function. The parameters of the NPID controller are tuned using real-coded genetic algorithms in terms of minimizing the objective function. The validity of the proposed method is examined by applying to a gas turbine engine and by conducting a simulation.

Perception Level of Foot Reflex Therapy and Its Related Factors among Customers using Foot Care Service Centers (전문 발 관리실 이용자의 발 반사요법 인식수준 및 관련요인)

  • Kim, Young-Ho;Kim, Pom-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.3
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    • pp.1350-1358
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    • 2013
  • For this study, in order to understand the perception level of foot reflex therapy and clarify its related factors among customers using foot care service centers, a survey was conducted based on structured self-administered questionnaire with 181 users of three foot care service centers located in Daejeon between September 1 and October 30, 2011. The results showed that the average score in perception level of the subjects regarding foot reflex therapy was $32.19{\pm}5.32$(Score scale of the 11 items 0-44) and people with higher level of education had a significantly higher perception level(p=0.020).The perception level based on attitude and practice of foot reflex therapy was significantly higher in the group who do it "to heal illness"(p=0.034); and who "had illness" at the time when they started the therapy (p=0.030); when they used the foot massage for a longer period (p=0.000); and those in the group who would "recommend it"(p=0.004). In multiple regression analysis, among the factors that affect perception level of foot reflex massage, reason for using foot reflex therapy, health state when starting foot reflex massage, period of using foot reflex massage, and experience of recommendation to other people were selected as significant variables, with the explanatory power of 26.1%. The results suggest that perception level of foot care service users regarding foot reflex therapy are more correlated to variables that explain their attitude and practice than general characteristic variables.

A Java Distributed Batch-processing System using Network of Workstation (워크스테이션 네트워크를 이용한 자바 분산 배치 처리 시스템)

  • Jeon, Jin-Su;Kim, Jeong-Seon
    • Journal of KIISE:Computing Practices and Letters
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    • v.5 no.5
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    • pp.583-594
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    • 1999
  • With the advance of VLSI and network technologies, it has now become a common practice to deploy a various forms of distributed computing environments. A study shows that a lot of network-aware computers are in an idle state for considerable amount of time depending on the types of users and time frames of the day. If we can take the full advantage of those idle computers, we can obtain the enormous combined processing power without further costly investment. In this paper, we present a distributed batch-processing system, called the Java Distributed Batch-processing System (JDBS), which allows us to execute CPU-intensive, independent jobs across a pool of idle workstations on top of extant distributed computing environments. Since JDBS is implemented using a Java programming language, it not only extends the scope of machine types that can be joined to the pool, but makes it a lot easier to build an entire system. Besides, JDBS is scalable and fault-tolerant due to its multi-cluster organization and intelligent strategies. A graphical user interface is also provided to facilitate the registration and unregistration, job submission, and job monitoring.

A study on the risks of terrorism raids in domestic occurring through of the Islamic State of IS terrorist groups (IS테러단체의 공습확대에 따른 자국 내 테러발생 위험성에 관한 연구)

  • Oh, Sei-Youen;Yun, Gyeng-Hui
    • Korean Security Journal
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    • no.42
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    • pp.277-308
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    • 2015
  • Recently the Japanese hostage crisis with Syria, the stake of the pilots IS of the terror group's affiliates like Kim incident occurred while urinarado IS not an exception anymore in connection with terrorism will not be able to do. In addition, particularly against terrorist groups worldwide, IS being a hero has been marginalized and wants uncritical drugs aimed at teens, such as dialog or game IS through SNS joined nationals as well as other countries, while recommending domestic complaints until the people power or luck, put the older brother can sign up for any terror group IS the terrorist group's terrorist acts while making the environment a national mark by foreigners or immigrants can be caused by the situation. Therefore, in this study, this IS serious for the terrorist acts of the terrorist group, IS due to the expansion of the domestic terrorist group caused the terror raids of about the dangers of foreign countries to review the case, and the incident has sought ways to prevent and respond to the rapporteur. The result IS due to the expansion of the domestic terrorist group caused the terror raids of the dangers of sex exists and that causes a response to the implements are as follows. First of all, IS brokering for the site of the terrorist group's approach to counter-terrorism Act will be a, and the next, each agency and terror for the information exchange and cooperation and serves as a reexamination of terror occurred through the quick and appropriate measures should be the language. Finally, the duties related to terrorism for teens, especially education and strengthen the safety program development and against terrorism should be carried out.

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Development and Application of Water Quality Level Model (WQLM) for the Small Streams of Rural Watersheds with Discriminant Analysis (판별분석을 통한 농촌유역 소하천의 수질등급모형(WQLM) 개발 및 적용)

  • Kim, Jin-Ho;Choi, Chul-Mann;Ryu, Jong-Soo;Jung, Goo-Bok;Shin, Joung-Du;Han, Kuk-Heon;Lee, Jung-Taek;Kwun, Soon-Kuk
    • Journal of Korean Society on Water Environment
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    • v.23 no.2
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    • pp.260-265
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    • 2007
  • This study was carried out to complement water quality standards and to establish new concept for water quality standards reflecting current state of water quality in small streams. By this purpose, discriminant analysis was performed and Water Quality Level Model (WQLM) was developed using the data such as EC, BOD, $COD_{Mn}$, SS, T-N, T-P, $NH_3-N$ in 224 agricultural streams. To give water quality level for water quality parameters, it divided into 20% respectively in the order of excellent water quality. On the basis of the lowest water quality level, water quality level of small streams is granted. As a result of it, number of stream corresponding to Level I was no, Level II was 2 streams, Level III was 22 streams, Level IV was 70 streams, and Level V was 130 streams. Average of water quality in each level was the highest in Level V. EC, SS, and T-N of 7 parameters were selected in variance concerned water quality level. By standardized canonical discriminant function coefficient, EC of three variances was the highest in 0.625 at the discriminant power. The next was T-N (0.509), SS (0.414). By discriminant function for water quality level, Level II was equal to $-2.973+19.376{\times}(EC)+0.647{\times}(T-N)+0.009{\times}(SS)$, Level III was equal to $-3.288+19.190{\times}(EC)+0.733{\times}(T-N)+0.041{\times}(SS)$, Level IV was equal to $-4.462+27.097{\times}(EC)+0.792{\times}(T-N)+0.053{\times}(SS)$, and Level V was equal to $-9.117+40.040{\times}(EC)+1.305{\times}(T-N)+0.111{\times}(SS)$. As a result of test at real agricultural watershed of Jeongan and Euidang in Gongju city, the fitness of WQLM was high to 88.78%. But, to get accomplished water quality assessment more exactly in agricultural streams, we had to concentrate and get vast data, and WQLM was modified and complemented continually.

Treatise is a Study on 風 in Terms of Oriental Medicine as well as the Philosophy (풍의 한의철학적 의미)

  • Hong Moo Hyung;Bae Hyun Su;Shin Min Kyu;Hong Moo Chang;Kim Soo Joong
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.17 no.4
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    • pp.861-878
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    • 2003
  • In the ancient time wind is considered as the life . soul and the human's breath which represents essence of universal creation and the absolute power and also the messenger of the god or god's state. Greek's 'pneuma' , India's 'Brahman' and the Old Testament's 'ruach' are used to signify the wind. Also Wind(風) in traditional culture, it is related to 玄妙之道 of 花郞, the flower of youth in Shilla dynasty and sexual intercourse in shaman's dream which can be thought as Freud's libido. In this aspect we can see the connection between the wind and the libido which can be meaning of sexual desire. Ancient Chinese wrote word ‘風’ as phoenix, the god's bird, the phoenix in inscriptions on bones and tortoise carapace(甲骨文) because one can feel the wind but can’t see it. The word Ki(氣) origins from 風 therefore 風 is 氣's fundamental notion. The wind can be understood by ki which travels around the world to create all nature. And the Wind is associated with 風化, 玄鳥, 八僧舞, which are related with reproduction. In the book of change (周易) the 震巽卦 ; 雷風 come under wind which means the function of ki and also menas the 精(essence of life) of 恒久(eternity) means the reprodution ; that performs succession of life. In the Oriental Medicine 氣 is a phenomenon that appears by movement of Ki by 相火(Ministerial fire). 相火 is core of the succession of life which means preservation of descendants; therefore 風 has very similar concept with sexual desire. 風 is the beginning ki of universe and in human body aspect 風 belong to the Liver Meridian. If 風 makes movement then the Pericardium Meridian of Hand Kwolum responds and the genital organs which belongs to Liver Meridian of Leg Kwolum reproductive function by contraction and expansion. Generally 風 understood as movement and origination and this is recognized as meaning of 氣. Therefore as studied above the present writer believe m. participates closely to reproductive function.

High Energy Density Germanium Anodes for Next Generation Lithium Ion Batteries (다음세대 리튬이온 배터리용 고에너지 밀도 게르마늄 음극)

  • Ocon, Joey D.;Lee, Jae Kwang;Lee, Jaeyoung
    • Applied Chemistry for Engineering
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    • v.25 no.1
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    • pp.1-13
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    • 2014
  • Lithium ion batteries (LIBs) are the state-of-the-art technology among electrochemical energy storage and conversion cells, and are still considered the most attractive class of battery in the future due to their high specific energy density, high efficiency, and long cycle life. Rapid development of power-hungry commercial electronics and large-scale energy storage applications (e.g. off-peak electrical energy storage), however, requires novel anode materials that have higher energy densities to replace conventional graphite electrodes. Germanium (Ge) and silicon (Si) are thought to be ideal prospect candidates for next generation LIB anodes due to their extremely high theoretical energy capacities. For instance, Ge offers relatively lower volume change during cycling, better Li insertion/extraction kinetics, and higher electronic conductivity than Si. In this focused review, we briefly describe the basic concepts of LIBs and then look at the characteristics of ideal anode materials that can provide greatly improved electrochemical performance, including high capacity, better cycling behavior, and rate capability. We then discuss how, in the future, Ge anode materials (Ge and Ge oxides, Ge-carbon composites, and other Ge-based composites) could increase the capacity of today's Li batteries. In recent years, considerable efforts have been made to fulfill the requirements of excellent anode materials, especially using these materials at the nanoscale. This article shall serve as a handy reference, as well as starting point, for future research related to high capacity LIB anodes, especially based on semiconductor Ge and Si.

A Study on the Stress and Dietary Life of Office Workers in Seoul (서울시내 직장인의 스트레스와 식생활관리)

  • 김종군;김정미;최미경
    • Korean journal of food and cookery science
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    • v.19 no.4
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    • pp.413-422
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    • 2003
  • The purpose of this study was to investigate the relationship between the dietary attitude and health on the stress status of office - workers in Seoul. This research was conducted on 389 office workers (224 males and 165 female). In relation to stress, it was found that the degree of stress as an office workers was ′slight′ and much for 45.2% and 40.6%, respectively, of the study population. Consequently, most office workers were found to be under stress. The amount of food intake under stress was found to be ′reduced′, unchanged and increased in 38.3, 37.0 and 24.7%, respectively, of those surveyed. The preferred foods when under stress were found to be alcoholic and non-alcoholic beverages, in 57.6% of cases, which was the highest proportion regardless of age, sex, marital status, occupation and educational level. The desired taste when under stress was found to be ′hot′ and sweet in 34.7 and 26.0%, respectively. As to the feeling after food intake, 51.7% responded that food intake was not useful for the relief of stress, which was the highest proportion and many salaried females worried about weight gain. With regard to the relationship between stress, health and nutrition, 69.9% of office workers responded that they thought the relationship of these factors was very high. As for the greatest cause triggering stress, 50.3% responded "due to workplace and job". The best method for relieving stress was to do exercise, with a 30.1 % response, The average score for the degree of stress and tension was 7.2, with 64.0% of office workers having an average level between 6- and 9. The degree of stress was higher for females than males, for unmarried salaried and hot-tempered persons. Those not doing exercise were subject to the highest levels of stress, and those a having sufficient sleep were found to be subject to less stress. Those interested in their health were found to have a good condition and lower levels of stress. In correlation with eating habits, stress, the degree of tension and personality, the F-value was found to be 43.505 (p<0.01), with an explanatory power of 0.294 (29.4%), indicating significant differences. This means that office workers with higher degrees of stress and tension tended to have poorer eating habits. Since bad eating habits have an adverse effect on both the state of physical health and individuals emotional development, for the purpose of correctly managing stress, office workers should make efforts to practice good eating habits.

Magritte's drawings and Lacan's Subject theory: Gaze, Encounter with the world (마그리트 회화와 라캉의 주체론 - 응시, 세계와의 조우)

  • Baek, Jin-Hwa
    • The Journal of Art Theory & Practice
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    • no.5
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    • pp.7-24
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    • 2007
  • The subject is connected with a structure named "The Symbolic" to Lacan, but he denied that the subject is explained simply as a fruit of language and "Other". From his point of view, passing through Subject, De-formation and Crack over it is designated as foundation of generation and creation rather than our destined defect. It should not be understood that subject of "The Real" is a concept of the subject free itself from restraint of "The Symbolic". However, this does not mean he asserts "Subject" is something incapable of being controlled by the unknown power. The problem is that this autonomous existence meets inside of it with something "more than one's own self" by "circulating around itself" like a permanent star. This is the indication of a "stranger in the middle of my privacy", or "extimit$\'{e}$", a coined-word by Lacan. Perhaps "Subject" is nothing more than the name of distance of object which is "too hot" to come close, and of this circulating movement. It's because of this object that the real subject stands against generalization and the subject can't be restored to any place in symbolic order-even though it is empty. The part which is told from Lacan's structural theory, that is to say, an importance to Lacan is that his Subject theory is not suggested or denied as a manual structure. On the contrary, it is a study of the relationship between the settled symbol that included in "real subject which is a unconscious one" and the symbolic subject hold- that is a metaphysical subject in general meaning. In Lacan's enlarged concept of subject beyond symbolic reality, it is noticeable that it gives justifiability to the union of a medium of different nature in artistic expression. We can recognize that the unconscious world is a living space which enables it to be a "condition of human being", not something dark under the surface of water through Magritte's(Rene Magritte, 1898~1967) surrealistic works. In other words, Magritte's art secures a core dimension of human nature through a mysterious gap of conscious and settled space. Magritte's drawings often evokes strange and unsettling feelings in people who view his paintings. This is because routine objects are found in "unsuitable" places from which we usually find them in our everyday lives. "Reality" in Magritte's paintings makes it aware that it is a strained field of concealment and disclosure basically between truths, and we can learn that his behavior to overturn to paint in-visible things is finally an effort to restore the "real subject" to the viewer's reality. In other words, such reversion arouses a nostalgic desire for the objects existing in their original appearance as they are - natural condition that our gaze had not been distorted yet by anamorphic stains. - and the state when we are conscious of them normally. Such desire offers an opportunity for us to get out of mental depression rather than operates to us as an abnormal crack. It's a successive process of effort to search for lost subject and Paradise Lost facing up to reality of subject human that is to be a subject of world and life are ousted from their place by structure and authority of culture.

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