• 제목/요약/키워드: case-series study

검색결과 1,580건 처리시간 0.033초

야전데이터를 활용한 무기체계 신뢰성 평가: K계열 무기체계 사례 중심 (Reliability Evaluation of Weapon System using Field Data: Focusing on Case Study of K-series Weapon System)

  • 정일한;이학용;박영일
    • 품질경영학회지
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    • 제40권3호
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    • pp.278-285
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    • 2012
  • Purpose: Weapon systems have the long life cycle unlike the consumer product. Thus, the reliability of weapon system is improved during the life cycle through the steady technical change. In this paper, we deal with the method of evaluating the reliability of weapon system with the field failure data. Methods: Especially, we present how to gather the field failure data and evaluate the reliability through the case of K-series weapon system. To evaluate reliability, the reliability growth model is used and the result is discussed. Results: It is steadily improved the reliability of K-series weapon system deployed from 2000 to 2004. The frequency of the failures that affect the mission is largely reduced and MTBMF(mean time between mission failure) is also improved. Conclusion: We can guess the trend of the reliability of weapon system with the field data through this study. Furthermore, it can be used to improve the reliability and make maintenance policy.

IGARCH and Stochastic Volatility : Case Study

  • Hwang, S.Y.;Park, J.A.
    • Journal of the Korean Data and Information Science Society
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    • 제16권4호
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    • pp.835-841
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    • 2005
  • IGARCH and Stochastic Volatility Model(SVM, for short) have frequently provided useful approximations to the real aspects of financial time series. This article is concerned with modeling various Korean financial time series using both IGARCH and stochastic volatility models. Daily data sets with sample period ranging from 2000 and 2004 including KOSPI, KOSDAQ and won-dollar exchange rate are comparatively analyzed using IGARCH and SVM.

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NILRADICALS OF POWER SERIES RINGS AND NIL POWER SERIES RINGS

  • HUH, CHAN;KIM, CHOL ON;KIM, EUN JEONG;KIM, HONG KEE;LEE, YANG
    • 대한수학회지
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    • 제42권5호
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    • pp.1003-1015
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    • 2005
  • Klein proved that polynomial rings over nil rings of bounded index are also nil of bounded index; while Puczylowski and Smoktunowicz described the nilradical of a power series ring with an indeterminate. We extend these results to those with any set of commuting indeterminates. We also study prime radicals of power series rings over some class of rings containing the case of bounded index, finding some examples which elaborate our arguments; and we prove that R is a PI ring of bounded index then the power series ring R[[X]], with X any set of indeterminates over R, is also a PI ring of bounded index, obtaining the Klein's result for polynomial rings as a corollary.

Analysis of Multivariate Financial Time Series Using Cointegration : Case Study

  • Choi, M.S.;Park, J.A.;Hwang, S.Y.
    • Journal of the Korean Data and Information Science Society
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    • 제18권1호
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    • pp.73-80
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    • 2007
  • Cointegration(together with VARMA(vector ARMA)) has been proven to be useful for analyzing multivariate non-stationary data in the field of financial time series. It provides a linear combination (which turns out to be stationary series) of non-stationary component series. This linear combination equation is referred to as long term equilibrium between the component series. We consider two sets of Korean bivariate financial time series and then illustrate cointegration analysis. Specifically estimated VAR(vector AR) and VECM(vector error correction model) are obtained and CV(cointegrating vector) is found for each data sets.

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중국에서의 파킨슨병 침치료 임상연구 동향 (Acupuncture for Parkinson's Disease in China)

  • 김락형;장인수;강세영
    • Korean Journal of Acupuncture
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    • 제28권4호
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    • pp.147-158
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    • 2011
  • Objectives : The purpose of this study was to obtain some knowledge about the acupuncture treatments on Parkinson's disease for the future practice and the research from the clinical studies in China. Methods : The literatures were searched using the data base-China Academic Journals (CAJ) (1994-2011). Clinical studies of acupuncture for Parkinson's disease such as randomized controlled trial (RCT), non-randomized controlled trial (NRCT), case series, case report were included. Results : Of 145 articles, 52 Clinical studies met our inclusion criteria: 20 RCTs, 7 NRCTs, 22 case series and 3 case reports. Various kinds of acupuncture treatments such as scalp acupuncture, body acupuncture, abdominal acupuncture, acupoint injection, eye acupuncture and thick needle acupuncture (粗鍼) were used in the clinical studies. The treatment and control groups take Madopa Tablet (Levodopa + Benserazide HCl) in the same time in many studies, and Madopa treatment was used as a comparative treatment in the most of studies. Acupuncture treatment was done daily or 2~3 times a week for 2~20 weeks. All of studies reported high effective rate in the treatment group compared to control group. Conclusions : The results of this study could be used for the future study about the acupuncture therapy for Parkinson's disease.

갱년기 증상에 대한 한약 사용 - 국내 한의 임상연구 분석 (Usage of Korean Herbal Medicine for Climacteric Symptoms - Analysis of Korean Clinical Studies)

  • 배민정;하재운;윤영주
    • 대한예방한의학회지
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    • 제27권2호
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    • pp.85-107
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    • 2023
  • Objective : To investigate the usage of Korean herbal medicine (KHM) for climacteric symptoms, this study reviewed clinical studies conducted in Korea. Method : Literature search was performed on three Korean database; OASIS, RISS and NDSL. Studies published before July 2023 were categorized and analyzed according to the study type and herbal prescriptions. Results : Fifty-eight studies including 7 controlled trial, 27 case series and 24 single case reports were included in our review and the total number of case patients was 420. 52 prescriptions based on syndrome identifications and 11 prescriptions of Sasang constitutions were used and the most frequently used prescriptions were Soyosan(逍遙散) and Guibitang(歸脾湯). Thirty-two prescriptions were also mentioned in previous delphi research or clinical practice guideline, and the rest were not. Thirty-five studies used acupuncture combined with KHM and 10 studies used pharmacopuncture and 5 studies used herbal hipbath. Conclusion : To increase the therapeutic effect of KHM and establish KHM as an alternative to hormone treatment, various prescriptions should be used according to syndrome identifications in the clinical field. High-quality RCTs on frequently used prescriptions and the development of various type of KHM are also necessary.

소청룡탕(小靑龍湯)의 군신좌사(君臣佐使) 배오(配伍) 분석 (Compatibility Analysis Through the System of Chief, Deputy, Assistant, and Envoy for Socheongnyong-tang)

  • 김도회;윤미정;신순식
    • 대한한의학방제학회지
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    • 제26권4호
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    • pp.363-380
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    • 2018
  • Objectives : We analyzed the principle of compatibility of socheongnyong-tang and expanded the range of application in clinical practice. Methods : Socheongnyong-tang was analyzed by the compatibility principle through the system of chief, deputy, assistant, and envoy, but the basic formulas of "Discussion of Cold Damage" and "Synopsis of the Golden Chamber" was used. Results : Socheongnyong-tang treats exterior wind-cold and interior water accumulation. Exterior wind-cold is treated mainly by exterior-releasing herbs constituting mahwang-tang and gyeji-tang in "Discussion of Cold Damage", and interior water accumulation is treated mainly by retained fluid-resolving herbs constituting yeonggamomigangsinha-tang, yeonggamomigagangsinbanhahaengin-tang and yeonggamomigagangsinbanhaengdaehwang-tang in "Synopsis of the Golden Chamber". Depending on the weight of exterior wind-cold and interior water accumulation, the disease condition is classified as a case where exterior wind-cold is heavier than interior water accumulation, a case where exterior wind-cold is lighter than interior water accumulation, and a case where it is equivalent. When exterior wind-cold is heavier than interior water accumulation, chief herbs are Ephedrae Herba and Cinnamomi Ramulus of exterior-releasing herbs series and deputy herbs are Zingiberis Rhizoma and Asari Radix et Rhizoma of retained fluid-resolving herbs series. When exterior wind-cold is equal to the disease condition of interior water accumulation, chief herbs are Ephedrae Herba of exterior-releasing herbs series and Zingiberis Rhizoma of retained fluid-resolving herbs series, and deputy herbs are Cinnamomi Ramulus of the exterior-releasing herbs series and Asari Radix et Rhizoma of retained fluid-resolving herbs series. When exterior wind-cold is lighter than interior water accumulation, chief herbs are Zingiberis Rhizoma and Asari Radix et Rhizoma of retained fluid-resolving herbs series and deputy herbs are Ephedrae Herba and Cinnamomi Ramulus of exterior-releasing herbs series. In any case, assistant herbs are Pinelliae Rhizoma, Paeoniae Radix alba, and Schisandrae Fructus, and envoy herb is Glycyrrhizae Radix preparata. Conclusions : In conclusion, socheongnyong-tang must differently formulate the system of chief, deputy, assistant, and envoy according to the grade of exterior wind-cold and interior water accumulation. These results suggest that socheongnyong-tang can be applied flexibly when applied in clinical practice to enhance the therapeutic effect.

CAJ 검색을 통해 살펴 본 중국에서의 역류성 식도질환 침구치료 임상연구 동향에 대한 고찰 (A Review on Clinical Studies of the Acupuncture and Moxibustion Therapy for Gastroesophageal Reflux Disease in China by Searching CAJ)

  • 강세영
    • Korean Journal of Acupuncture
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    • 제32권1호
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    • pp.1-12
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    • 2015
  • Objectives : The purpose of this study was to review the acupuncture and moxibustion therapy for gastroesophageal reflux disease(GERD) in China. Methods : The literatures were searched using the database-China Academic Journals(CAJ)(~2015.1.). Clinical studies of acupuncture and moxibustion therapy for GERD such as randomized controlled trial(RCT), non-randomized controlled trial(NRCT), case series, or case report were included. Results : Thirty studies met our inclusion criteria: 24 RCTs, 4 NRCTs, 1 case series, 1 case report. Various kinds of treatment such as body acupuncture, abdominal acupuncture, acupuncture therapy with finger on back-shu point, electroacupuncture, acupoint injection, auricular acupuncture, and moxibustion were used in the clinical studies. The treatment groups take herbal medicines at the same time in 16 studies, and proton pump inhibitor(PPI) and histamine 2 receptor antagonist were used as a comparative treatment in the most of studies. Acupuncture or moxibustion treatments were done daily or 2~3 times a week for 5 days~18 weeks. All of studies reported higher effective rate in the acupuncture or moxibustion treatment group compared to the western medication control group. Conclusions : The results of this study could be used for the future practice and the clinical research about the acupuncture and moxibustion therapy for GERD.

저압배선계통에서 직렬아크의 검출에 관한 연구 (A Study on the Series Arc Detection in Low-voltage Wiring Systems)

  • 김일권;박대원;최수연;박찬용;김황국;길경석
    • 한국전기전자재료학회논문지
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    • 제21권2호
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    • pp.182-187
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    • 2008
  • This paper dealt with the detection algorithm of series arcing, which is a cause of electric fires in low-voltage wiring systems. To find the distinguished electrical features of series arc, we simulated series arcing by the arc generator specified in UL1699. An electric heater, an inverter-controlled vacuum cleaner, and a phase-controlled incandescent lamp were used as loads to generate series arcing. A high-pass filter (HPF) with the low cut-off frequency of 3 kHz at -3 dB was fabricated and applied to separate the series arc signal from the AC voltage source. The experiment showed that the high frequency signal generates randomly during series arcing, and the phase-controlled incandescent lamp produces high frequency pulses even in normal state. In this case, the magnitude, the width, and the randomness of high frequency signal should be analyzed to estimate series arcing precisely.