• 농업과학연구
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• 제9권1호
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• pp.260-268
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• 1982

본연구(本硏究)는 우리나라 사유림소유자(私有林所有者)의 산림시업의식(山林施業意識)과 이에 영향(影響)을 미치는 제요인(諸要因)과의 관계(關係)를 개별적(個別的) 또는 종합적(綜合的)으로 구명(究明)하여, 임업기술지도(林業技術指導) 및 사유림시책입안(私有林施策立案)에 필요(必要)한 기초자료(基礎資料)를 제시(提示)하는데 목적(目的)을 두고 수행(修行)하였으며, 연구자료(硏究資料)는 81, 11~82, 1월(月) 사이에 179명(名)의 일반산주(一般山主)와 83명(名)의 독림가(篤林家)를 대상(對象)으로 조사(調査)하였다. 종속변수(從屬變數)로서의 산림시업의식(山林施業意識)은 Likert 형척도(型尺度)에 의하여 평점(評點)하였으며, 독립변수(獨立變數)는 연령(年令), 교육수준(敎育水準), 임야면적(林野面積), 사회경제적지위(社會經濟的地位), 전달매개수단(傳達媒介手段), 사회심리(社會心理)의 6개요인(個要因)으로서 변수간(變數間)의 상호연관성(相互聯關性)을 일반산주(一般山主), 독림가별(篤林家別)로 비교분석(比較分析) 하였다. 지금까지의 연구결과(硏究結果)를 요약(要約)하면 다음과 같다. 1. 산림시업의식(山林施業意識)의 평균점수(平均點數)는 일반산주(一般山主)가 독림가(篤林家)보다 2점(點)정도 낮았으며, 그 차이(差異)는 유의적(有意的)이었다. 한편, 독립변수(獨立變數)로서의 산주연령(山主年令), 임야면적(林野面積), 사회경제적지위(社會經濟的地位) 및 전달매개변수(傳達媒介變數)의 평균점수(平均點數)도 일반산주(一般山主)가 낮았으나, 사회심리변수(社會心理變數)만은 두 산주집단(山主集團)사이에 유의차(有意差)가 없었다. 2. 일반산주(一般山主의 산림시업의식(山林施業意識)은 연령변수(年令變數)와 매우 유의적(有意的)인 부(負)의 상관(相關)을 이루고 있었으며, 그 밖의 독립변수(獨立變數)와는 정(正)의 상관(相關)을 나타내었다. 반면(反面)에 독림가(篤林家)의 시업의식(施業意識)은 교육수준변수(敎育水準變數)와 유의적(有意的)적인 부(負)의 상관(相關)을 이루고 있었으며, 연령(年令), 전달매개(傳達媒介) 및 사회심리변수(社會心理變數)와는 정(正)의 상관(相關)을 보였다. 3. 산림시업의식(山林施業意識)과 6개독립변수간(個獨立變數間)의 중상관계수(重相關係數)는 일반산주(一般山主)가 0.6971, 독림가(篤林家)가 0.5207 로서 매우 유의적(有意的)이었다. 시업의식변량(施業意識變量)에 대한 독립변수(獨立變數)의 상대적(相對的) 영향력(影響力)은 일반산주(一般山主)의 경우 사회심리변수(社會心理變數)에 의하여 41.0%가 설명(說明)되고, 독림가(篤林家)의 경우는 사회심리변수(社會心理變數)에 의하여 16.2%, 연령변수(年令變數)에 의하여 6.0%가 설명(說明)되는 것으로 나타났다. 4. 전체산주(全體山主)의 시업의식(施業意識)에 대한 7가지 사회심리성격(社會心理性格)의 중상관계수(重相關係數)는 0.6566으로서 매우 유의적(有意的)이었으며, 이러한 7가지 성격요인(性格要因)은 통합적(統合的)으로 종속변량(從屬變量)을 43.1% 설명(說明)할 수 있다. 그리고, 이 43.1%는 다시 무의욕적성격(無意慾的性格)에 의하여 15% 전통적가정관(傳統的家庭觀)에 의하여 11.2%가 설명(說明)되는 것으로 나타났다. 5. 결국(結局) 우리나라 사유림소유자(私有林所有者)의 산림시업의식(山林施業意識)은 대부분(大部分) 경제적요인(經濟的要因) 보다는 심리적(心理的)인 요인(要因)에 의하여 결정(決定)되므로 임업지도활동(林業指導活動)을 통하여 사회심리적요인(社會心理的要因)을 개선(改善)해 나갈 필요(必要)가 있다.

• 응용통계연구
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• 제33권4호
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• pp.365-377
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• 2020

선형모형에서 두개 이상의 설명변수들 사이에 존재하는 다중공선성 문제를 변수들 간에 내재되어 있는 공통의 구조인 인자를 구성하고, 인자들을 회귀변수로 사용하여 해결하는 인자회귀모형에 대하여 논의한다. 무한개로 가정 가능한 내재된 인자 중 유의미한 인자적재행렬을 구성하기 위하여 벌점모수의 값이 큰 LASSO 사전분포를 적용하는 베이지안 추정법을 사용한다. 결정된 인자적재행렬과 다른 모수들의 추정값을 각 설명변수의 선형모수로 역변환 하여, 새로운 관측값에 대한 예측 모형으로도 사용한다. 제안한 방법을 제품 서비스 관리 자료에 적용하여 정해진 인자의 개수에 대한 인자가 일반적인 공통인자회귀모형과 동일한 결과를 나타냄을 확인하였고, 일반적인 공통인자회귀모형과 비교를 위해 계산한 평균 제곱 오차값이 더 작다는 것을 알 수 있었다.

• 한국도로학회논문집
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• 제19권5호
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• pp.143-151
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• 2017

PURPOSES : The purpose of this study is to develop models of accidents occurring at circular intersections related to the time of day and night and driver gender, and to provide countermeasures for safer circular intersections. METHODS : Seventy intersections built before 2008 were surveyed for inclusion in the modeling. Traffic accident data from 2008 to 2014 were collected from the TAAS data set of the Road Traffic Authority. Sixteen variables explaining the accidents including geometry and traffic volume were selected from the literature and seven multiple linear regression models were developed using SPSS 20.0. RESULTS : First, the null hypotheses, that the number of traffic accidents are not related to driver gender or time of day, were rejected at a 5% level of significance. Second, seven statistically significant accident models with $R^2$ value of 0.643-0.890 were developed. Third, in daytime models by gender, when the right-turn-only lane was selected as the common variable, the number of lanes, presence of driveways and speed humps, diagrammatic exit destination sign, and total entering traffic volume were evaluated as specific variables. Finally, in nighttime models by gender, when the diagrammatic exit destination sign was selected as the common variable, total entering traffic volume, presence of right-turn-only lanes, number of circulatory road way lanes, and presence of splitter islands and driveways were identified as specific variables. CONCLUSIONS:This study developed seven accident models and analyzed the common and specific variables by time of day and gender. The results suggest approaches to providing countermeasures for safer circular intersections.

• Journal of Chest Surgery
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• 제25권12호
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• pp.1570-1577
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• 1992

The vascular surgery is the field that has developed in early 20 century and is progressing nowadays. Recent advance in surgical technique accompanying with excellent medical diagnosis and treatment, prompt angiographic usage, development of variable prosthetic material, and concomitant use of anti-coagulant have made remarkable results of vascular surgery. 83 cases of vascular surgery have been performed at Thoracic and Cardiovascular Surgery Department of Pusan National Unversity Hosaital since 1971 till 1990, for 20 years and their results are followed. Patient ductus arteriosus and Buerger`s disease were omited in this study. 1. The age distribution shows that the fifth and sixth decades are most frequently affected and mean age was 56.1 years old. Male to female ratio is 1: 2.32. 2. Among the 83 cases of all, number of occlusive vascular disease is 46 and that of aneurysmal disease is 33. 3. In clinical manifestation, most common symptom of occlusive disease is pulselessness and pain was next. Mass sensation is most commonly complained by patients of aneurysmal disease. 4. CT scan was more important in diagnosis of aneurysmal diseases and angiogram was more commonly used in occlusive diseases. 5. The common site of arterial occlusion was common iliac artery, femoral artery, aortic bifurcation, and external iliac artery, as its frequency rate. The most commonly affecting portion of aortic aneurysm was abdminal aorta, and descending thoracic aorta and femoral artery were next 6. Preoperative associated diseases were atherosclerosis[41 cases], hypertension[21 cases], valvular heart disease[11 cases], and diabetes mellitus[9 cases], etc, 7. Operative methods in ocllusive diseases were thrombectomy[36.9%], endarterectomy [10.9%], and bypass graft insertion[52.7%]. Among the bypass graft, Y-graft was used in 7 case, straight graft was used in 17 cases, and saphenous venous graft was used in 2 cases. 8. Postoperative complications were developed in 17 cases, and morbidity rate was 36. 9. Eleven patient were died within 1 month after operation, so operative mortality rate was 13.3%. 10. Duration of patency was beteween 7 and 58 months[average 27.5 months] in occlusive diseases and their 5-year patency rate was 56.3%. Duration of patency of aneurysmal disease was 20 months in aveage and their 5-year patency rate was 51.3%. 11. Patients of eleven cases of occlusive disease and two cases of aneurysmal disease required reoperation for variable reason. 12. 35 cases of patient have used anticoagulants: coumadin, ticlid, and persanthin-ASA combination.

• 아태비즈니스연구
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• 제15권2호
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• pp.207-222
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• 2024

Purpose - This study investigates whether the lagged price difference ratio between preferred and common stocks is related to the return and closing price of the preferred stock using three panel models. Design/methodology/approach - As a first step, we use a two-way fixed effect panel model with stationary preferred stock returns as a dependent variable. For robustness, we then apply the autoregressive distributed lag model (ARDL) and error correction model (ECM) with nonstationary closing prices of the preferred stocks as a dependent variable and compare the results of each model. The ARDL and ECM models provide an advantage of estimating a long-run equilibrium equation together if a long-run relationship exists between the two time-series variables compared to the fixed effect model. Findings - Our sample consists of 107 preferred stocks with at least four years of daily observations as of the end of December 2023. The coefficients of the error correction terms in the ARDL and ECM models are highly statistically significant, approximately -0.08. This indicates that the disequilibrium between the closing prices of common and preferred stocks adjusts by about 8% per day toward equilibrium. In all three models, the price difference ratio on day t-1 was statistically significant in explaining the preferred stock returns or closing prices on day t, implying that trading based on the previous day's price difference ratio is effective for one day. Research implications or Originality - Furthermore, the returns on preferred stocks are higher for firms with a lower proportion of foreign investors or a lower foreign market capitalization of preferred stocks. This suggests that foreign investors with informational advantages do not actively engage in profit-taking by trading preferred stocks, thus not narrowing the price difference. In summary, the recent surge in preferred stock prices is likely driven mainly by the irrational behavior of retail investors.

• Journal of Power Electronics
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• 제18권2호
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• pp.343-355
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• 2018

A wide-voltage-conversion range bidirectional DC-DC converter is proposed in this paper. The topology is comprised of one typical LC energy storage component and a special common grounded asymmetric H-bridge with four active power switches/anti-parallel diodes. The narrow output PWM voltage is generated from the voltage difference between two normal (wider) output PWM voltages from the asymmetric H-bridge with duty cycles close to 0.5. The equivalent switching frequency of the output PWM voltage is double the actual switching frequency, and a wide step-down/step-up ratio range is achieved. A 300W prototype has been constructed to validate the feasibility and effectiveness of the proposed bidirectional converter between the variable low voltage side (24V~48V) and the constant high voltage side (200V). The slave active power switches allow ZVS turn-on and turn-off without requiring any extra hardware. The maximum conversion efficiency is 94.7% in the step-down mode and 93.5% in the step-up mode. Therefore, the proposed bidirectional topology with a common ground is suitable for energy storage systems such as renewable power generation systems and electric vehicles with a hybrid energy source.

• Journal of Microbiology and Biotechnology
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• 제26권8호
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• pp.1473-1480
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• 2016

This study focused on the variations in the non-coding sequences between ctxB and rstR of various CTX phages. The non-coding sequences of CTX-1 and CTX-cla are phage type-specific. The length of the non-coding region of CTX-1 and CTX-cla is 601 and 730 nucleotides, respectively. The non-coding sequence of CTX phage could be divided into three regions. There is a phage type-specific Variable region between two homologous Common regions (Common regions 1 and 2). The non-coding sequence of RS1 element is similar to CTX-1 except that Common region 1 is replaced by a short RS1-specific sequence. The non-coding sequences of CTX-2 and CTX-cla are homologous, indicating the non-coding sequence of CTX-2 is derived from CTX-cla. The non-coding region of CTX-O139 is similar to CTX-cla and CTX-2; however, it contains an extra phage type-specific sequence between Common region 2 and rstR. The variations in the non-coding sequences of CTX phages might be associated with the difference in the replication efficiency and the directionality in the integration into the V. cholerae chromosome.

• 응용통계연구
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• 제27권7호
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• pp.1097-1114
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• 2014

연생보험은 보험가입자 2인의 생사여부에 따라 보험금을 지급하는 보험상품이다. 보험실무에서는 연생보험 가입자들의 장래생존기간을 독립으로 가정하고 보험료를 산출한다. 그러나 보험가입자들 사이에 존재하는 상관성을 고려할 때 이는 합리적이지 않다. 또한 보험가입자들의 생존분포와 독립적인 커먼-쇽(common shock)을 연생보험에 반영하면 다양한 지급조건을 설정할 수 있는데 이에 대한 충분한 고려가 이루어지지 않고 있다. 본 논문에서는 커먼-쇽(common shock)을 연생보험에 적용하고, 코퓰라(copula)를 이용하여 가입자들의 장래생존기간 간에 존재하는 상관성을 반영한 후 분석을 수행한다. 또한 연생보험가입자에 대한 확률변수를 추가적으로 고려하여 기존의 연생모형에서 다루지 못했던 새로운 상품을 설계하고 시뮬레이션을 통해 보험료를 계산한다. 그리고 그 결과를 바탕으로 본 논문에서 제시한 모형이 연생상품에 다양하게 적용 가능함을 논하고자 한다.

• International journal of advanced smart convergence
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• 제6권4호
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• pp.1-8
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• 2017

In this work, the effects of fairly influential factors on performance of vacuum system, such as constant pressure and outgassing effect were simulated to propose the optimum design factors. Outgassing effects of selected vacuum materials on the vacuum characteristics were simulated by the $VacSim^{Multi}$ simulation tool. This investigation examined the feasibility of reliably simulating the outgassing characteristics of common vacuum chamber materials (aluminum, copper, stainless steel, nickel plated steel, Viton A). The optimum design factors for vacuum systems were suggested based on the simulation results. And, the effects of throttle valve applications on vacuum characteristics were also simulated to obtain the optimum design model of variable conductance on high vacuum system. Simulated vacuum characteristics of the proposed modelling were agreed with the observed experimental behaviour of real systems. Pressure limit valve and normally on-off control valve were schematized as the modelling of throttle valve for the constant process-pressure. Simulation results were plotted as pump-down curve of chamber and variable conductance of throttle valve. Simulated behaviors showed the applications of throttle valve sustained the process-pressure constantly, stably, and reliably.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 추계학술대회 논문집 학회본부
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• pp.391-395
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• 1990

A new control algorithm is developed to achieve the robust performance of the system during the overall control process. Time-varying sliding manifolds are proposed to remove the reaching phase which is one of common shortcomings of variable structure control scheme. A necessary and sufficient condition for the existence of a sliding mode on the newly proposed time-varying sliding mode on the newly proposed time-varying sliding manifolds is derived by Lyapunov's second method. The digital simulation results show that the newly proposed control algorithm is superior to the typical variable structure control algorithm with respect to the robust performance of the system. The simplicity of the proposed control algorithm encourages control engineers to implement the proposed control algorithm in many control problems.