• Title/Summary/Keyword: 누적분석

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Genetic Diversity of Rana catesbiana Captured on various sites in Korea based on mitochondrial ND1 sequence (미토콘드리아 ND1 유전자 염기서열 비교를 통한 국내 서식 황소개구리의 유전적 다양성 조사)

  • Lee Ji-Young;Shim Jae-Man;Joung Insil
    • Proceedings of the KAIS Fall Conference
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    • 2005.05a
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    • pp.297-300
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    • 2005
  • 1970년대 식용을 위한 양식을 목적으로 일본에서 수입된 황소개구리가 국내 하천과 호서생태계에 큰 피해를 주었으나, 최근 급속히 그 개체수가 줄어든 것으로 추정되므로 이번 연구에서는 국내에 서식하는 북미산 황소개구리의 유전자 분석을 통하여 개체동태군에 대한 유전적 연관을 조사하였다. 이를 위하여 전라남도 지역에서 서식하는 황소개구리를 채집하여 이미 발표된 북미산 황소개구리와 미토콘드리아 ND1/tRNA 유전자 1215bp의 염기서열을 비교, 분석하였다. 북미산과 비교하였을 때 조사한 국내 서식 개체 모두에게 ND1/tRNA 유전자 1개 위치에서 염기변화가 발견되었으나 이는 도입 개체군의 유전자인지 국내 특이변이가 진행된 것인지 확실하지 않다. 또한 조사한 개체 일부에서 유전자 염기서열의 6위치에서의 변이가 발견되었으나 국내 서식 황소개구리는 미국산 황소개구리와의 유전적 차이가 거의 없으며, Kimura-2-parameter 분석결과 국내 서식 황소개구리 개체 내에서 $98.7\%\~100\%$의 높은 유사성을 보여 종내 유전적 차이가 거의 없는 것으로 보인다. Neighbor-Joining과 Maximum Parsimony 분석 결과, cluster를 이루는 개체군의 차이를 보였으므로 개체들이 분화되어 나온 시점과 위치가 다른 것으로 확인되었지만 장흥, 영암, 고흥의 개체가 국내 도입시기의 개체군에 속하며 광주, 남평 지역의 개체군이 고흥의 한 개체로부터 분화되어 나왔음을 추정할 수 있다. 이러한 결과로부터 국내에 서식하는 황소개구리가 도입 후 지역 특이적 분화가 일어났다고 결정하기는 무리가 있으며, 이와 같이 유전적 유전도가 높은 개체들간의 교배에 따른 유전적유전적 다양성의 감소가 최근에 관찰되는 국내산 황소개구리의 급격한 감소원인들 중의 하나일 가능성을 시사한다.년도) 18,756, 2045(년도) 22,595, 시장점유율 증가로 인한 수출액 증가분 누적(억원) : 2015(년도) 3,411, 2025(년도) 8,847, 2035(년도) 14,433, 2045(년도) 18,005 또한 시나리오 비교평가를 실시하여 본 결과, 본 연구에서 정의한 순편익 누적(Cumulative Net Profit) 변수를 적용하면 현재 연구비 추세 대비 $30\%$ 까지 연구비를 증가 시키는 것이 효율적임을 알 수 있었다.성, 생산 용이성, 제품 디자인의 우수한 정도가 a=0.01 수준 하에서 유의적으로 추정되었다. 이들 변수들 중에서 품질경쟁력에 가장 큰 영향을 미치는 측정변수는 제품의 기본 성능, 수명(내구성), 신뢰성, 제품 디자인의 순서로 추정되었다. 이것은 한국 제조업이 아직 산업 디자인이 품질경쟁력에 크게 영향을 미치는 성숙단계에 이르지 못하였음을 의미한다. (2) 제품 디자인에게 영향을 끼치는 유의적인 변수는 연구개발력, 연구개발투자 수준, 혁신활동 수준(5S, TPM, 6Sigma 운동, QC 등)이며, 제품 디자인은 우선 품질경쟁력을 높여 간접적으로 고객만족과 고객 충성을 유발하는 것으로 추정되었다. 상기의 분석결과로부터, 본 연구는 다음과 같은 정책적 함의를 도출하였다. 첫째, 신상품 개발과 혁신을 위한 포괄적인 연구개발 프로젝트를 품질 경쟁력의 주요 결정요인(제품의 기본성능, 신뢰성, 수명(내구성) 및 제품 디자인)과 연계하여 추진해야 할 것이다. 둘째, 기업은 디자인 경영 마인드 제고와 디자인 전문인력 양성을, 대학은 디자인 현장 업무를 통하여 창의력 증진과 기획 및 마케팅 능력 교육을, 정부는 디자인 기술개발 및 디자인 교육지원의 강화를 통하여 각각 디자인 경쟁력$\rightarrow$품질경쟁력을 제고시켜야 할 것이

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An Empirical Analysis of Stock Price Reaction to M&A in Liner Shipping Companies (정기선사 M&A와 주가수익률 실증분석)

  • Park, Seon-Na;Lee, Ki-Hwan
    • Journal of Korea Port Economic Association
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    • v.28 no.1
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    • pp.179-201
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    • 2012
  • Since 1993, M&A activities have been frequent in Liner shipping market. This study examines the effect of M&A on stock price reaction for acquiring firms listed on the market. The study covers the period from 1993 to 2009 and uses 61 daily closing prices of the acquiring firms before and after the M&A announcement day and is analyzed through the market-adjusted model in an event study. After calculating short-term performance using abnormal returns(AR) and cumulative average abnormal returns(CAR) before and after 30 days from the day of event, the results on the test show that the firm's values slightly increased through the M&A, but it does not attest to the statistical significance. In addition, this study investigates the AR difference between estimating windows and post-event windows for the 3 cases of each period before and after 30 days, 15 days, and 7 days from the event day to analyse the impact of M&A on the addition of acquiring firm's value. Our findings suggest that the M&A between Liner shipping companies is targeted for the long-term business strategy instead of the instant rise in the value of the firm involved.

Assessment of the Effect of Geographic Factors and Rainfall on Erosion and Deposition (지형학적 인자 및 강우량에 따른 침식 및 퇴적의 영향 평가)

  • Yu, Wan-Sik;Lee, Gi-Ha;Jung, Kwan-Sue
    • Journal of the Korean Society of Hazard Mitigation
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    • v.11 no.2
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    • pp.103-112
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    • 2011
  • This study aims to demonstrate the relationship between various factors and soil erosion or deposition, simulated from distributed rainfall-sediment-runoff model applications. We selected area, overland flow length, local slope as catchment representative characteristics among many important geographic factors and also used the grid-based accumulated rainfall as a representative hydro-climatic factor to assess the effect of these two different types of factors on erosion and deposition. The study catchment was divided based on the Strahler's stream order method for analysis of the relationship between area and erosion or deposition. Both erosion and deposition increased linearly as the catchment area became larger. Erosion occurred widely throughout the catchment, whereas deposition was observed at the grid-cells near the channel network with short overland flow lengths and mild slopes. In addition, the relationship results between grid-based accumulated rainfall and soil erosion or deposition showed that erosion increased gradually as rainfall amount increased, whereas deposition responded irregularly to variations in rainfall. Within the context of these results, it can be concluded that deposition is closely related with the geographic factors used in this study while erosion is significantly affected by rainfall.

Target Localization Method based on Extended Kalman Filter using Multipath Time Difference of Arrival (다중경로 도달시간차이를 이용한 확장칼만필터 기반의 표적 위치추정 기법)

  • Cho, Hyeon-Deok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.6
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    • pp.251-257
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    • 2021
  • An underwater platform operating a passive sonar needs to acquire the target position to perform its mission. In an environment where sea-floor reflections exist, the position of a target can be estimated using the difference in the arrival time between the signals received through multipaths. In this paper, a method of localization for passive sonar is introduced, based on the EKF (Extended Kalman Filter) using the multipath time difference of arrival in underwater environments. TMA (Target Motion Analysis) requires accumulated measurements for long periods and has limitations on own-ship movement, allowing it to be used only in certain situations. The proposed method uses an EKF, which takes measurements of the time differences of the signal arrival in multipath environments. The method allows for target localization without restrictions on own-ship movement or the need for an observation time. To analyze the performance of the proposed method, simulation according to the distance and depth of the target was performed repeatedly, and the localization error according to the distance and water depth were analyzed. In addition, the correlation with the estimated position error was assessed by analyzing the arrival time difference according to the water depth.

The Effect of Meteorological Factors on PM10 Depletion in the Atmosphere and Evaluation of Rainwater Quality (기상인자에 따른 대기 중 미세먼지 감소 및 빗물 특성 연구)

  • Park, Hyemin;Kim, Taeyong;Yang, Minjune
    • Korean Journal of Remote Sensing
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    • v.36 no.6_3
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    • pp.1733-1741
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    • 2020
  • This study analyzed the effect of meteorological factors on the concentration of PM10 (particulate matter 10) in the atmosphere and the variation of rainwater quality using multivariate statistical analysis. The concentration of PM10 in the atmosphere was continuously measured during eleven precipitation events with a custom-built PM sensor node. A total of 183 rainwater samples were analyzed for pH, EC (electrical conductivity), and water-soluble cations (Na+, Mg2+, K+, Ca2+, NH4+) and anions (Cl-, NO3-, SO42-). The data has been analyzed using two multivariate statistical techniques (principal component analysis, PCA, and Pearson correlation analysis) to identify relationships among PM10 concentrations in the atmosphere, meteorological factors, and rainwater quality factors. When the rainfall intensity was relatively strong (> 5 mm/h, rainfall type 1), the PM10 concentration in the atmosphere showed a negative correlation (r = -0.55, p < 0.05) with cumulative rainfall. The PM10 concentration increased the concentration of water-soluble ions (r = 0.25) and EC (r = 0.4), and decreased the pH (r = -0.7) of rainwater samples. However, for rainfall type 2 (< 5 mm/h), there was no negative correlation between the PM10 concentration in the atmosphere and cumulative rainfall and no statistically significant correlation between the PM10 concentration in the atmosphere and rainwater quality.

Overreaction Hypothesis and Aftermarket Performance of the U.K. IPOS (과잉반응가설과 영국 최초공모주의 장기성과 분석)

  • Lee, Ki-Hwan
    • The Korean Journal of Financial Management
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    • v.12 no.1
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    • pp.187-210
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    • 1995
  • 본고(本槁)에서는 영국기업의 최초공모주를 이용하여 최초공모주(最初公募株) 시장(市場)에 나타나는 3가지 이례현상(異例現象) 즉 단기(短期)에 있어 최초공모주의 저가발행현상(低價發行現象), 장기(長期)에 있어 최초공모주의 저성과현상(低成果現象) 그리고 hot issue market 존재를 분석하고 있다. 이러한 분석은 주로 미국(美國) 발행시장(發行市場)을 대상으로 이루어져 왔는바, 시장의 효율성 측면에서 비슷한 수준을 유지하고 있는 영국(英國)의 증권시장(證券市場)에서도 이러한 현상이 나타나는지를 조사해보는 것은 의미가 있을 뿐만아니라 이러한 현상이 다른 시장에서도 통상 나타나는 현상인지를 밝히는데도 의의가 있다고 보여진다. 영국(英國)의 최초공모주(最初公募株) 시장(市場)에서의 3가지 이례현상(異例現象)을 분석하기 위해 우선 거래 첫날의 시장조정수익률(市場調整收益率)을 계산하여 신규공모주가 시장가격에 비해 할인(割引)되어 발행되는지를 조사한 결과 시장가격에 비해 12.88% 정도 할인발행되고 있음이 밝혀졌다. 단기의 저가발행현상(低價發行現象)과는 달리 신규공모주가 시장에 상장된지 3년이 경과한 후 추정된 장기투자수익률(長期投資收益率)은 12.05%의 부(負)의 누적초과수익률(累積超過收益率)을 시현하고 있는데 이는 과잉반응가설(過剩反應假說)에 의해 설명되고 있다. 끝으로 1987년의 최초공모주가 다른 연도에 비해 다섯배 정도로 저가발행되고 있음을 밝힘으로써 영국발행시장(英國發行市場)에도 hot issue market 현상이 나타남을 분석하고 있다.

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Real-time brain mapping system using EEG and evoke potential (뇌파 및 Evoke potential을 이용한 실시간 Brain mapping system)

  • Cho, Sang-Heum;Kim, Pan-Ki;Park, Sue-Kyoung;Kim, Ji-Eun;Song, Eun;Kang, Mahn-Hee;Ahn, Chang-Beom
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.1983-1984
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    • 2008
  • 뇌 활동의 전기적 신호인 뇌파(EEG)와 외부 자극에 대한 유발 전위(EP)를 측정하여 실시간으로 뇌지형도를 생성하는 real-time brain mapping system을 개발하였다. 측정 전극은 32채널을 사용하였고, EEG를 실시간 및 누적 주파수 분석을 통한 뇌파의 활성도 진단, EP를 측정하여 시각적/청각적 자극에 의한 유발 전위 분석을 할 수 있다. 본 시스템은 측정 대상군의 통계적 분석을 위한 Database를 구축하였고, 신뢰성 높은 뇌파 및 유발 전위 신호를 위하여 실시간 측정과정 및 측정 후 Data 검토과정에서 다양한 Artifact 제거 알고리즘이 도입되었다. 또한, 32 채널 Brain map을 구성하여 뇌파를 공간적으로 분석 가능하며, 시간 및 주파수의 증가에 따라 Brain map을 동영상화하여 시간적/주파수적 변화에 따른 분석이 가능하다.

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An Empirical Study on the Relationship between the Pnline WOMs and the Number of Audience of Successful Films (흥행영화의 온라인 구전패턴과 관객수의 관계에 대한 실증연구)

  • Hwang, Yena;Nam, Yoonjae
    • The Journal of the Korea Contents Association
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    • v.19 no.5
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    • pp.147-162
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    • 2019
  • This study investigates the relationship between the online WOMs(such as volume of blogs, articles, reviews, searches) and the number of audience of successful film.The results are as follow: Frist, using a curve-estimation method, the results show that the longitudinal trends of the online WOMs can be best described by a cubic indicating. Second, using panel analysis in model(t) the volume of blogs, reviews, and searches is positively associated with the number of audience. All of the variables' coefficient are significant. However the volume of articles is negatively related to the number of audience with a significant coefficient.

The Cumulative Recurrence Rate of Colonic Adenomatous Polyps After Colon Polypectomy in a Single University Hospital Health Check-up Examinees (일개 대학병원 건강검진 수진자를 대상으로 한 선종성 대장용종절제술 후 대장용종의 누적재발률)

  • Hwang, Hye-Lim;Jung, Woo-Geun;Kim, Yun-Jin;Lee, Sang-Yeoup;Cho, Byung-Mann;Yi, Yu-Hyeon;Cho, Young-Hye;Tak, Young-Jin;Jeong, Dong-Wook;Lee, Jeong-Gyu
    • Journal of agricultural medicine and community health
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    • v.39 no.3
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    • pp.137-145
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    • 2014
  • Objectives: Colonoscopy is a popular tool for screening for colon cancer throughout the world. The incidence of polypectomy and follow-up colonoscopy are persistently increasing but the studies about follow-up test after polypectomy are still lack of its domestic sources. This study is designed to look into the recurrence rate of colon polyps and risk factors after polypectomy. Methods: This is a retrospective study by reviewing medical charts of 147 patients who underwent polypectomy and follow-up colonoscopy from Jan. 2000 to Mar. 2008. The Kudo classification was used to describe the polyps found in the colonoscopy. The follow-up period was defined as the term between polypectomy and the first colonoscopy follow up. Results: Seventy six point two percent of the enrolled patient were male and the mean age was $56.5{\pm}8.1$. Mean follow-up period was $24.9{\pm}13.7$ (6 - 65) months. The cumulative recurrence rate of 1 year was 11.6%. The rate of 2 years was 36.7% and that of 3 years was 55.8%. The number of polyps was the factor which statistically showed significant relation of its recurrence rate. The histological morphology characteristic of polyps could be one independent factor which may be associated to the recurrence of polyps. Conclusions: The importance of colonoscopy follow up after polypectomy was clearly emphasized through the cumulative recurrence rate of 55.8%. Therefore, there is a need for more domestic studies with a large number of patients about the recurrence of polyps after polypectomy.

Effects of Harvest Time on Growth and Phytochemical Contents of Baby Leaf Vegetables in Multi-layer System (다단재배에서 수확시기가 어린잎 채소의 생육과 항산화물질 함량에 미치는 영향)

  • Kim, Jae Kyung;Kang, Ho Min;Kim, Il Seop;Choi, Eun Young;Choi, Ki Yong
    • Journal of Bio-Environment Control
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    • v.26 no.3
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    • pp.194-200
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    • 2017
  • This study aimed to determine the suitable of harvest time on the growth and quality of baby leafy vegetables (Agastsche rugosa O. Kuntze and Lepidium sativum L.) grown on rice seedling tray in a six-layered bench system at 30cm intervals in order to exploit the space during rice growing off-season. Seedlings were grown on the rice seedling tray for 10 days after sowing with coir substrate supplied with nutrient solution at EC $1.5dS{\cdot}m^{-1}$ every 2 days prior to placing the tray on the bench, which were at $1^{st}$ (Low) layer above 20cm and $6^{th}$ (High) layer above 170cm apart from the ground. Growth and phytochemical contents were measured at 7-day and 14-day harvest time. During the culture periods, daily average of integrated solar radiation and temperature were $9.3{\sim}9.6MJ{\cdot}m^{-2}$, $27.5^{\circ}C$ in the High layer and $5.1{\sim}6.2MJ{\cdot}m^{-2}$ in average, and $26.5{\sim}26.6^{\circ}C$ in the Low layer, respectively. For A. rugosa, the highest growth was observed in the Low layer bench at a 14-day harvest time, while their plant height in the High layer was shorter and the leaf number was lower. For L. sativum, the plant height, leaf length and width, leaf number and fresh weight were higher in the Low layer. For A. rugosa, a high yield was observed with the increase in integrated temperature and integrated solar radiation, while a higher yield of L. sativum was found with the increase in integrated temperature, but not with integrated solar radiation. For A. rugosa, both polyphenol and anthocyanin contents were higher in the High layer at a 14-day harvest time. For L. sativum, polyphenol contents were higher in the High layer, whereas no significant difference in anthocyanin and flavonoid contents was observed depending on the layer and harvest time. The highest chlorophyll content showed in Low layer at a 7-day harvest time in both A. rugose and L. sativum. All of the results suggest that in terms of growth and quality, it may be better growing in the high layer for 14 days after seedling in A. rugosa, and low layer for 7 days in L. sativum.