• 산업경영시스템학회지
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• 제6권8호
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• pp.93-103
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• 1983

In this paper, we study an optimal service policy of the M/M/2/K queueing system with two types of customers. The incurred costs consist of waiting cost, service cost and incurred costs consist of waiting cost, service cut and changeover cost. The changeover cost occurs when a server who assigned to serve a particular type of customers reassigned to the other types of customers. Two servers serve two types of customers who arrive to the two separate queues. The two types of customers differ in respect of their arrival rate, service rate, waiting cost, and service cost. The servers require a policy, for determining when they should change their service type, which minimizes the long run expected total cost. The policy is obtained by a Markov decision process model that consists of a finite number of states and actions. In order to find the optimal service policy, we define states and actions of the system, compute onestep transition probabilities, and apply to the successive approximations algorithm.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 추계 학술논문 발표대회
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• pp.206-207
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• 2013

In the recent years, the subject of the M&A of construction company has become one of important issue in the domestic construction industry. Therefore, the purpose of this research consider the rational plans of M&A not only for systematizing types about process of M&A in construction industry, but also for analyzing the significant characteristic of M&A in korea. To achieve this objective, this research performs a case study of M&A to embody the major trend and implications. The results of this research based on this methodology can be systematized as falling into two areas : 1)the primary types of M&A were divided into 4 categories by analyzing the results of interview, 2)the process of M& A from the result of case study.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 추계학술대회 논문집
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• pp.287-292
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• 2001

Static behaviors of railway plate girder bridges designed by the L-22, a standard load type of the railway specification in Korea, are evaluated by widely eight load cases. The load cases are three real loads, which contain three locomotive types of Saemaul PMC, diesel, and Korea Train Express(KTX), and three design loads, L-22, L-18, and HL-25 loads, in railway specification. Plate girders for analysis have the length of spans of six types：6m, 9m, 12m, 22m, 24m, and 30m. For analysis SAP2000n ,a commercial FEM tool, is used. Dominant axial load types are taken from these results that are maximum deflections, reaction forces, and absolute maximum bending moment in girders.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2002년도 추계학술발표대회
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• pp.189-194
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• 2002

This study aimed at the design trends and characteristics of flexible housing unit plan. In this paper, flexible unit plans of 256 examples that are constructed or will be constructed from 1991 to 2005 on the basis of the initial year of dwelling are analyzed. Divided into 60$m^2$, 85$m^2$, 102$m^2$, 135$m^2$, 165$m^2$ and above 180$m^2$ areas, kinds, characteristics and trend of planning of flexible housing unit plan are analyzed with the frequency and percentage method. The results of this study are as follows; 16 types of flexible kinds; room and living roon/room and room/room, room and living room. Since 2000, various types of flexible planning have came into existence (12 types of 16 types). 3bay is next to 4bay in number of flexible housing planning. There are R/L type in 3bay, R/L type and R/R types in 4bay. Flexible space organization is differentiated various types in R/L and public-private space has expanded in many ways.

• Journal of Microbiology and Biotechnology
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• 제26권2호
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• pp.270-276
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• 2016

Extended-spectrum β-lactamases (ESBLs), particularly those of the CTX-M types, are the predominant resistance determinants of Escherichia coli that are rapidly spreading worldwide. To determine CTX-M types, E. coli isolates were collected from retail chickens (n = 390) and environmental samples from chicken farms (n = 32) and slaughterhouses (n = 67) in Korea. Fifteen strains harboring bla_CTX-M genes were isolated from 358 E. coli isolates. The most common CTX-M type was eight of CTX-M-15, followed by six of CTX-M-1 and one of CTX-M-14. The bla_CTX-M genes were identified in the isolates from retail chickens (n = 9), followed by feces, water pipes, floors, and walls. Conjugations confirmed the transferability of the plasmids carrying bla_CTX-M genes to the recipient E. coli J53 strain. Furthermore, eight addiction systems carried by the replicons in CTX-M types were confirmed. The dominant system was identified as ccdAB, vagCD, and pndAC in donor strains and transconjugants. The clonal relationship between the two strains carrying bla_CTX-M genes indicates that E. coli may transmit from the farm to retail chickens, suggesting a possible public health risk. Our findings demonstrate that the detection of CTX-M types in E. coli isolates is important for tracking ESBL production in animals, and suggest linkage of multiple addiction systems in plasmids bearing bla_CTX-M genes.

• 경영과학
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• 제32권2호
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• pp.91-109
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• 2015

The M&A of firms has been emerged as the effective means of fast diversification and growth in dynamic environment. However, the empirical research about M&A in Korea has not been implemented rich due to the difficulty of obtaining M&A data. In this research, we empirically investigate the relationships among M&A, environment and firms' performance focused on Korean manufacturing firms, understanding the current practice of M&A in Korea. We use the Manufacturing Productivity Panel Survey Data, which are collected by Korea Productivity Center in 2013. The sample size is 575 and the sample is divided into M&A group and non-M&A group. We conduct logit analysis with the independent variables of environment factors (munificence, dynamic, uncertainty), and firms' performance (sales growth, ROS, labor productivity and Inventory turnover), and dependent variable of M&A group or non M&A group. The results show that M&A is closely related to environment feature and firm performance: M&A firms are likely to be the higher munificence and dynamic and the lower sales growth and higher profitability than non-M&A group. In addition, we also examine the characteristics of firms by M&A types (competitors, customer/supplier and firms from unrelated industry). These results imply that if firms confront the pressure of uncertainty (dynamic) and the lower growth, they tend to choose M&A. Futhermore, to profoundly understand the behavior of firms about M&A, it is required to classify the M&A firms by merge types.

• 대한가정학회지
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• 제44권5호
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• pp.99-107
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• 2006

The purposes of this study are to identify the types of teacher efficacy, to present a theoretical base for teacher efficacy among Home Economics teachers and subsequently, to improve the quality in the practices of home economics education. To achieve these purposes, 263 secondary school home economics teachers were surveyed by the prime investigator. The three research questions of this study were: 1. What are the individual characteristics, the environmental characteristics and the trends of teacher efficacy among secondary school home economics teachers? 2. What is the factor in teacher efficacy among secondary school home economics teachers? 3. What are the types of teacher efficacy among secondary school home economics teachers? For these research questions, factor analysis and cluster analysis were conducted. The factor analysis on teacher efficacy with a survey of secondary school home economics teachers produced 5 factors of efficacy: classroom management, needs assistance, instructional strategies, environmental assistance and teaming assistance. The teacher efficacy had a mean of 3.58 and the home economics teachers showed a slightly higher level in teacher efficacy. Of the 5 efficacy factors, classroom management showed the highest level (M=3.89), followed by learning assistance (M=3.81), instrumental strategies (M=3.57), environmental assistance (M=3.42) and needs assistance (M=3.19). Overall, the teachers had positive feeling in teacher efficacy. Three types of teachers were found in the types of teacher efficacy: the supreme, the average and the efforts-needy. Those types were identified based on the mean scores of the five sub-domains from the factor analysis. To enhance the teacher efficacy, the needs assessments for the students and behavioral adjustment issues should be reflected in the curriculum of teacher education and workshops. The primary investigator suggested that continuous and long-term plans for teacher education need to be developed because short-term plans may not be effective in changing attitudes such as teacher efficacy.

• 한국항해학회지
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• 제18권2호
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• pp.19-40
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• 1994

Several factors can be chosen for evaluating seakeeping performance, such as deck wetness, propeller racing, slamming, rolling, vertical acceleration and vertical bending moment, in consi-deration of the safety of human being, cargo and ship. In fact, there are few developments for an evalua-tion method of seakeepting performance correponding with each ship's characteristics. The purpose of this paper is to develop an quantitative evaluation method of seakeeping performance according to ship types. The scope and the method of this study are as follow. (1) Obtain each response amplitude of ship's motion in waves by Ordinary Strip Method and apply it to short-crested, irregular wave for random process of the factors on seakeeping performance. (2) Define the evaluation index, the dangerousness, the maximum dangerousness and the evaluation diagram. (3) Figure out the different characteristics according to ship types by computer simulation of evaluating seakeeping performance. (4) Adopt vertical acceleration and one of rolling or lateral acceleration as the factors on seakeeping performance by clarifying the correlation of stochastic process. This study developed an evaluation method coincident with each ship's characteristics, and suggested a device for application to actual ship. This method might be useful in developing the practical system of seakeeping performance in accordance with ship types. The ship models for computer simulation are 175m container ship types, 93m tranning ship HANARA as passenger ship type, 259m bulk-carrier type and 164m pure car-carrier type.

• 한국산림과학회지
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• 제90권3호
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• pp.295-305
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• 2001

본 연구는 우리나라 온대 중 북부지방의 천연 활엽수림을 대표하는 강원도 평창 지역을 대상으로 입지유형을 해발고도(1,000m 이상, 700~1,000m, 700m 미만) 및 지형(능선, 사면, 계곡)에 따라 9가지로 구분하여 정밀 임분조사를 실시하고, 각 입지유형별 임분구조의 파악과 경쟁관계를 구명함으로써, 천연 활엽수림의 친환경적 경영방안에 필요한 기초 자료를 제공하기 위하여 수행하였다. 입지유형별 임분의 생장은 700~1,000m에서 가장 양호한 것으로 나타났으며, 종 다양성도와 풍부도는 해발고도가 낮아질수록 증가하는 것으로 파악되었다. 또한 지형별로는 능선, 사면, 계곡의 순서로 재적 등의 임분 상태가 양호한 것으로 나타났으며, 한 수종의 상대우점도가 높은 입지유형에서는 균재도는 낮은 값을 보이고 있었다. 입지유형별 최적 경쟁지수 모형은 7개 입지유형에서 거리독립경쟁지수가 선정되었으며, 1,000m 이상의 능선과 700~1,000m의 계곡에서만 거리종속경쟁지수가 흉고직경 정기평균 생장량과 높은 상관을 나타내어 입지유형별로 다소 다른 결과를 보였다. 입지유형에 따른 수종별 생장특성과 경쟁관계를 분석한 결과 상대우점도가 높은 수종들이 상대적으로 경쟁 상태도 양호한 것으로 나타났다. 신갈나무는 해발고도 700m 이상의 지형에서 생장이 우수하였고, 음나무의 경우에는 해발고도 1,000m 이상의 지형과 700~1,000m의 능선에서 상대우점도가 상대적으로 낮았음에도 불구하고 높은 경쟁력을 유지하고 있는 것으로 파악되었다. 또한 느릅나무와 다릅나무는 1,000m 미만의 지형에서 다른 수종보다 높은 경쟁력을 보이고 있어, 앞으로 이러한 입지유형별 수종분포 및 경쟁관계를 고려한 무육작업이 필요할 것으로 보인다.

• Journal of Ecology and Environment
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• 제47권3호
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• pp.75-84
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• 2023

Background: Knowledge of the spatial trends of plant invasions in different habitats is essential for a better understanding of the process of these invasions. We examined the variation in invasive alien plant species (IAS) richness and composition at two spatial scales defined by elevation and habitat types (roadside, forest, and cultivated lands) in the Makawanpur district of Nepal. Following an elevation gradient ranging from 500 to 2,400 m asl along a mountain road, plant species cover was recorded within sample plots of size 10 m × 5 m. Systematic random sampling was adopted in every 100 m elevation intervals on three habitat types. Results: Altogether 18 invasive alien plants belonging to eight families were recorded within 60 plots, of which 14 species (representing 80%) were from tropical North and South America. The most common plants by their frequency were Ageratina adenophora, Chromolaena odorata, Bidens pilosa, Lantana camara, and Parthenium hysterophorus. We found a significant relationship between species composition and elevation in the study area. Low-elevation regions had a higher number of alien species as compared to high-elevation regions within different habitat types. Conclusions: The species richness and density of IAS were higher in the road site followed by the cultivated land and forest sites. This pattern occurred throughout the elevation range and habitats. IAS were found mostly in the open land with high sunlight availability. Information from such scientific assessment of invasive alien plants will assist in developing appropriate management plans in the Makawanpur district.