• 제목/요약/키워드: dynamic shifts

검색결과 59건 처리시간 0.034초

Microbiota Analysis and Microbiological Hazard Assessment in Chinese Chive (Allium tuberosum Rottler) Depending on Retail Types

  • Seo, Dong Woo;Yum, Su-jin;Lee, Heoun Reoul;Kim, Seung Min;Jeong, Hee Gon
    • Journal of Microbiology and Biotechnology
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    • 제32권2호
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    • pp.195-204
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    • 2022
  • Chinese chive (Allium tuberosum Rottler) has potential risks associated with pathogenic bacterial contamination as it is usually consumed raw. In this study, we investigated the microbiota of Chinese chives purchased from traditional markets and grocery stores in March (Spring) and June (Summer) 2017. Differences in bacterial diversity were observed, and the microbial composition varied across sampling times and sites. In June, potential pathogenic genera, such as Escherichia, Enterobacter, and Pantoea, accounted for a high proportion of the microbiota in samples purchased from the traditional market. A large number of pathogenic bacteria (Acinetobacter lwoffii, Bacillus cereus, Klebsiella pneumoniae, and Serratia marcescens) were detected in the June samples at a relatively high rate. In addition, the influence of the washing treatment on Chinese chive microbiota was analyzed. After storage at 26℃, the washing treatment accelerated the growth of enterohemorrhagic Escherichia coli (EHEC) because it caused dynamic shifts in Chinese chive indigenous microbiota. These results expand our knowledge of the microbiota in Chinese chives and provide data for the prediction and prevention of food-borne illnesses.

데이터마이닝을 활용한 동적인 고객분석에 따른 고객관계관리 기법 (Customer Relationship Management Techniques Based on Dynamic Customer Analysis Utilizing Data Mining)

  • 하성호;이재신
    • 지능정보연구
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    • 제9권3호
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    • pp.23-47
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    • 2003
  • 전통적인 고객관계관리 연구는 특정 시점에서 고객관계관리에 중점을 두어 연구되었다. 이러한 정적인 고객관계관리와 고객 행동에 관한 지식은 마케팅 관리자가 제한된 마케팅 자원을 이익의 극대화를 위해 사용할 수 있게 해주었다. 그러나 시간이 경과하게 되면 이러한 정적인 지식은 쓸모가 없어지게 된다. 그러므로 고객관계관리는 고객의 동적 특성을 반영해야 한다. 과거 고객의 구매 행위를 관찰하여 현재 또는 미래 시장의 고객을 세분화하며 구분된 고객 군집에 대해 서로 다른 마케팅 전략을 사용할 수 있다. 고객의 구매행동을 근간으로 한 고객관계관리는 수십 년 전부터 연구되어왔지만 동적인 고객관계관리에 대한 연구는 최근에 들어와서야 활발하게 진행되고 있다. 본 논문은 인터넷 상점의 고객 데이터로부터 추출된 지식과 시간 경과에 따른 고객 행동 패턴의 분석을 위해 데이터마이닝과 모니터링 에이전트 시스템(MAS)을 이용하며, 이를 통한 동적인 고객관계관리 모델을 제시한다. 이 모델은 고객이력경로에 대한 예측과 고객에게 나타나는 집단이력경로의 분석, 그리고 시간 경과에 따른 고객 군집의 변화에 대한 분석과 그에 따른 마케팅 전략 도출을 포함한다. 이 모델의 제안은 많은 온라인 소매상이 직면하고 있는 경영상의 문제를 해결하는데 유용할 것이다.

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주식유통시장의 층위이동과 장기기억과정 (Level Shifts and Long-term Memory in Stock Distribution Markets)

  • 정진택
    • 유통과학연구
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    • 제14권1호
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    • pp.93-102
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    • 2016
  • Purpose - The purpose of paper is studying the static and dynamic side for long-term memory storage properties, and increase the explanatory power regarding the long-term memory process by looking at the long-term storage attributes, Korea Composite Stock Price Index. The reason for the use of GPH statistic is to derive the modified statistic Korea's stock market, and to research a process of long-term memory. Research design, data, and methodology - Level shifts were subjected to be an empirical analysis by applying the GPH method. It has been modified by taking into account the daily log return of the Korea Composite Stock Price Index a. The Data, used for the stock market to analyze whether deciding the action by the long-term memory process, yield daily stock price index of the Korea Composite Stock Price Index and the rate of return a log. The studies were proceeded with long-term memory and long-term semiparametric method in deriving the long-term memory estimators. Chapter 2 examines the leading research, and Chapter 3 describes the long-term memory processes and estimation methods. GPH statistics induced modifications of statistics and discussed Whittle statistic. Chapter 4 used Korea Composite Stock Price Index to estimate the long-term memory process parameters. Chapter 6 presents the conclusions and implications. Results - If the price of the time series is generated by the abnormal process, it may be located in long-term memory by a time series. However, test results by price fixed GPH method is not followed by long-term memory process or fractional differential process. In the case of the time-series level shift, the present test method for a long-term memory processes has a considerable amount of bias, and there exists a structural change in the stock distribution market. This structural change has implications in level shift. Stratum level shift assays are not considered as shifted strata. They exist distinctly in the stock secondary market as bias, and are presented in the test statistic of non-long-term memory process. It also generates an error as a long-term memory that could lead to false results. Conclusions - Changes in long-term memory characteristics associated with level shift present the following two suggestions. One, if any impact outside is flowed for a long period of time, we can know that the long-term memory processes have characteristic of the average return gradually. When the investor makes an investment, the same reasoning applies to him in the light of the characteristics of the long-term memory. It is suggested that when investors make decisions on investment, it is necessary to consider the characters of the long-term storage in reference with causing investors to increase the uncertainty and potential. The other one is the thing which must be considered variously according to time-series. The research for price-earnings ratio and investment risk should be composed of the long-term memory characters, and it would have more predictability.

기업의 동태적 진화 및 적응 이론에 대한 비판적 고찰 : 적응에 있어 조직학습과 재구조화 관점을 중심으로 (Reconceptualizing the Dynamic Evolution of the Firm : On Learning and Restructuring in Adaptation)

  • 이종호
    • 한국지역지리학회지
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    • 제13권6호
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    • pp.623-638
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    • 2007
  • 본 논문은 환경 변화에 대한 기업의 동태적 적응 메카니즘을 설명하는 대조적인 두 이론을 고찰하고, 두 이론 간에 보완적 연계의 필요성을 밝히는 것이 그 목적이다. 1980년대 까지 재구조화론은 기업의 성공과 적응을 설명하는 지배적인 접근이었다. 그러나 이 접근은 환경 변화에 대해 어떻게 기업이 적응하는지, 기업들 간의 적응의 성패가 왜 상이하게 나타나는지에 대해 설명하지 않는다. 즉 재구조화론은 기업의 학습과 적응에 대한 맥락 특수적인 해석 시각을 제공하지 못한다. 한편 1990년대 이후에 기업의 학습과 진화에 대한 학문적 관심은 기업의 동태적 경쟁력을 이끄는 기업 학습의 본질을 고찰하는 것에 초점이 두어져 왔다. 조직학습론은 조직 진화에 있어 지식, 학습 그리고 역량의 중요성을 강조한다. 하지만 이 접근 또한 급진적인 환경 변화에 대한 기업의 적응 메커니즘에 대해서는 효과적으로 설명하지 못하고 있다. 본 연구는 이러한 맥락에서 기업의 동태적 적응과 진화는 재구조화 과정과 점진적 및 급진적 학습 과정의 길함을 통해 나타나는 사실을 설명하고, 이를 토대로 기업의 진화와 적응을 효과적으로 설명하기 위해서는 두 이론을 보완적으로 연계한 통합적 이론 체계가 구축될 필요가 있음을 제안한다.

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동적패널모형을 활용한 서울시 중소형 오피스 빌딩 임대료 결정 요인 연구: CBD(도심권)와 GBD(강남권) 비교를 중심으로 (A Study of Rent Determinants of Small and Medium-Sized Office Buildings in Seoul Using a Dynamic Panel Model: Focusing on CBD and GBD Comparison)

  • 김나라;유진석;김종진
    • 토지주택연구
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    • 제14권4호
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    • pp.47-62
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    • 2023
  • 본 연구는 오피스의 소비재 및 투자재 특성을 고려하여 거시경제변수와 미시특성변수를 포함한 모형을 구성하고, 유효 임대료 자료를 기반으로 국내 주요 업무지구인 도심권과 강남권 중소형 오피스 빌딩 임대료 결정요인을 비교 분석하여 투자적 시사점을 제시하고자 하였다. 분석방법은 시계열자료와 횡단면자료를 함께 포함하여 분석이 가능하며, 추정량 편의 가능성이 낮은 것으로 알려진 동적패널모형을 사용하였다. 두 모형의 분석결과를 요약하면 다음과 같다. 도심권·강남권 중소형 오피스 빌딩 임대료 영향 요인 분석결과 변수와 계수값 부호 측면에서 도심권 분석 결과와 동일하게 나타났다. 따라서 도심권과 강남권 중소형 오피스 빌딩의 임대료는 건물 및 입지특성과 함께 거시경제환경의 변화에 의해 영향을 받는 것으로 나타나 공간 소비재와 투자재의 특성을 모두 가지는 시장으로 해석된다. 위의 분석결과를 바탕으로 투자적 측면의 시사점은 다음과 같이 제시된다. 첫째, 도심권에 위치한 입지는 양호하지만 노후화된 중소형 오피스 빌딩의 재건축은 현실적으로 한계가 있다. 따라서 이러한 중소형 오피스 빌딩의 가치는 지속적으로 낮아질 가능성이 높아질 수 있어 투자시 이에 대한 고려가 필요하다. 둘째, 도심권의 경우 주차여건이 가격에 큰 영향을 줄 수 있으므로 도심권 중소형 오피스 빌딩 투자시 대상 빌딩의 주차환경과 개선 가능성에 대한 고려가 중요하다고 할 수 있다. 마지막으로 강남권 중소형 오피스 시장은 거시경제환경의 변화에 보다 민감한 시장으로 향후 이자율과 경제성장 등에 영향을 미칠 수 있는 통화정책 등의 변화를 주요한 투자기준으로 고려해야 할 필요성이 높다고 할 수 있다.

골프드라이빙 스트로크시 역학적 분석 (Mechanical Analysis of golf driving stroke motion)

  • 박광동
    • 한국운동역학회지
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    • 제12권1호
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    • pp.205-219
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    • 2002
  • This research seeks to identify the plantar pressure distribution graph and change in force in connection with effective golf drive strokes and thus to help ordinary golfers have appropriate understanding on the moving of the center of weight and learn desirable drive swing movements. To this end, we conducted surveys on five excellent golfers to analyze the plantar pressure applied when performing golf drive strokes, and suggested dynamic variables quantitatively. 1) Our research presents the desire movements as follows. For the time change in connection with the whole movement, as a golfer raises the club head horizontally low above ground from the address to the top swing, he makes a semicircle using the left elbow joint and shaft and slowly turns his body, thus lengthening the time. And, as the golfer twists the right waist from the middle swing to the impact with the head taking address movement, and does a quick movement, thus shortening the time. 2) For the change in pressure distribution by phase, to strike a strong shot with his weight imposed from the middle swing to the impact, a golfer uses centrifugal force, fixes his left foot, and makes impact. This showed greater pressure distribution on the left sole than on the right sole. 3) For the force distribution graph by phase, the force in the sole from the address to halfway swing movements is distributed to the left foot with 46% and to the right foot with 54%. And, with the starting of down swing, as the weight shifts to the left foot, the force is distributed to the left sole with 58%. Thus, during the impact and follow through movements, it is desirable for a golfer to allow his left foot to take the weight with the right foot balancing the body. 4) The maximum pressure distribution and average of the maximum force in connection with the whole movement changed as the left (foot) and right (foot) supported opposing force, and the maximum pressure distribution also showed much greater on the left sole.

Influence of ventilation rate on the aerodynamic interference between two extra-large indirect dry cooling towers by CFD

  • Ke, S.T.;Liang, J.;Zhao, L.;Ge, Y.J.
    • Wind and Structures
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    • 제20권3호
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    • pp.449-468
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    • 2015
  • Current wind-resistance designs of large-scale indirect dry cooling towers (IDCTs) exclude an important factor: the influence of the ventilation rate for radiator shutter on wind loads on the outer surfaces of the tower shell. More seemingly overlooked aspects are the effects of various ventilation rates on the wind pressure distribution on the tower surfaces of two IDCTs, and the feature of the flow field around them. In order to investigate the effects of the radiator shutter ventilation rates on the aerodynamic interference between IDCTs, this paper established the numerical wind tunnel model based on the Computational Fluid Dynamic (CFD) technology, and analyzed the influences of various radiator shutter ventilation rates on the aerodynamic loads acting upon a single and two extra-large IDCTs during building, installation, and operation stages. Through the comparison with the results of physical wind tunnel test and different design codes, the results indicated that: the influence of the ventilation rate on the flow field and shape coefficients on the outer surface of a single IDCT is weak, and the curve of mean shape coefficients is close to the reference curve provided by the current design code. In a two-tower combination, the ventilation rate significantly affects the downwind surface of the front tower and the upwind surface of the back tower, and the larger positive pressure shifts down along the upwind surface of the back tower as the ventilation rate increases. The ventilation rate significantly influences the drag force coefficient of the back tower in a two-tower combination, the drag force coefficient increases with the ventilation rate and reaches the maximum in a building status of full ventilation, and the maximum drag coefficient is 11% greater than that with complete closure.

Position Change of the Neurovascular Structures around the Carpal Tunnel with Dynamic Wrist Motion

  • Kwon, Jae-Yoel;Kim, Ji-Young;Hong, Jae-Taek;Sung, Jae-Hoon;Son, Byung-Chul;Lee, Sang-Won
    • Journal of Korean Neurosurgical Society
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    • 제50권4호
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    • pp.377-380
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    • 2011
  • Objective : The purpose of this study was to determine the anatomic relationships between neurovascular structures and the transverse carpal ligament so as to avoid complications during endoscopic carpal tunnel surgery. Methods : Twenty-eight patients (age range, 35-69 years) with carpal tunnel syndrome were entered into the study. We examined through wrist magnetic resonance imaging in three different positions (neutral, radial flexion, and ulnar flexion) and determined several anatomic landmark (distance from the hamate hook to the median nerve, ulnar nerve, and ulnar vessel) based on the lateral margin of the hook of the hamate. The median nerve and ulnar neurovascular structure were studied with the wrist in the neutral, ulnar, and radial flexion positions. Results : The ulnar neurovascular structures usually passed just over or ulnar to the hook of the hamate. However, in 12 hands, a looped ulnar artery coursed 0.6-3.3 mm radial to the hook of the hamate and continued to the superficial palmar arch. The looped ulnar artery migrates on the ulnar side of Guyon's canal (-5.2-1.8 mm radial to the hook of the hamate) with the wrist in radial flexion. During ulnar flexion of the wrist, the ulnar artery shifts more radially beyond the hook of the hamate (-2.5-5.7 mm). Conclusion : It is appropriate to transect the ligament greater than 4 mm apart from the lateral margin of the hook of the hamate without placing the edge of the scalpel toward the ulnar side. We would also recommend not transecting the transverse carpal ligament in the ulnar flexed wrist position to protect the ulnar neurovascular structure.

색의 공간 구성적 차원에 관한 색채해석학적 연구 (A chroma-hermeneutical Study on the Space-constituitive Dimension of Color)

  • 이란표
    • 한국실내디자인학회논문집
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    • 제13권5호
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    • pp.181-189
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    • 2004
  • This study consists of two parts, in which the traditional discourses about light and color are analysed hermeneutically, The first part deals with the optical and chromatic discourse that stands in the same context with the aesthetic, and the second with the analysis of color phenomenon that is constituitive of space. From the ancient time the basic parameters of the conceptual thinking such as the virtual, simulacrum, have sticked to the inevitable status, which mediates to represent the original that can never present by oneself. In modern times this specificity of the virtual could have been connected with the problem, how and by which means objects can be perceived and grasped in itself. Among the barometers to the problem ‘color’ or ‘color perception’ has been regarded as the distinct one, in which the relationship between the image and the identifying of this one, the relationship between the perceived image and the perceiving subject and the problem of the spatiality of color and surface can be dwelled on. Through the explication of the chromatic and aesthetic discourse it can be recognized that color, surface and space are interacted with one another. Colors on the surface are not only the dynamic interpoints between the memory and the forgetfulness, but also the virtual interfaces, in which the spatialising actions happen incessantly. At this point it can be illuminated that the space-constituitive dimension of color is correlative with the dimension of chromatic effects of spatialising. Therefore color as well as surface as the spatial happening must be apprehended as the one, which constitutes the spatialising and at the same time varies and shifts itself into another on the purpose of the other spatialising.

항공기 세로축 무게중심의 변화에 따른 민감도 해석에 관한 연구 (A Study on Aircraft Sensitivity Analysis for C.G Variation of Longitudinal Axis)

  • 김종섭
    • 한국항공우주학회지
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    • 제34권6호
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    • pp.83-91
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    • 2006
  • 현대의 고성능 전투기는 공력성능 및 조종성능의 향상을 위하여 대부분 세로축 방향으로 항공기를 불안정하게 설계하는 정안정성 완화 개념을 채택하고 있다. 비행제어법칙의 설계 작업은 불안정하게 설계된 항공기에 안정성을 부여하고, 주어진 비행임무에 대하여 만족스런 조종성능을 발휘할 수 있도록 비행성능을 조작하는 일련의 과정이다. 세로축 무게중심은 무장형상, 연료상태 및 착륙장치의 위치에 영향을 받으며 항공기 안정성에 많은 영향을 미친다. 따라서 무게중심의 이동은 세로축 안정도 여유에 영향을 미친다. 본 논문에서는 운용 시에 발생 가능한 최대 후방 무게중심에 대해 항공기 안정성을 해석하였고, 비행시험을 통해 최종적으로 검증하였다. 선형해석 항목은 세로축 단주기 모드 특성 및 안정도 여유에 관하여 행하였으며, 비선형 해석 항목은 단주기 모드를 해석하기 위해 세로축 가진 입력에 대한 항공기 응답특성을 분석하였다. 또한, 최대 후방 무게중심에서 수행된 고받음각 비행시험 자료를 제시함으로써 T-50 고등훈련기의 비행 안정성을 제시하였다.