• 한국산림과학회지
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• 제97권5호
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• pp.501-507
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• 2008

The data of crown width with 4 directions, DBH, tree height, and coordinate for sample trees were collected from 30 permanent sample plots in secondary fore st of the Maoershan Experimental Forestry Farm, Northeast China. In this paper, the competition of individual trees in stand were discussed for secondary forest by using iterative Hegyi competition index and crown overlap index that represented the competitive and cooperative interactions among neighboring trees. Active competitors of subject tree in the competition zone were selected to calculate the iterative competition index. Using the results of crown classification based on the equal crown projection area, a new distance dependent competition index called crown overlap index (COI) was developed for secondary forest. The COI performed well in describing the crown competition rather than crown competition factor (CCF). The individual-based competition index discussed in this paper will provide more precise for developing individual tree growth models for secondary forest and it can also use to adjust the stand structure for spatial optimal management.

• 대한수학회보
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• 제48권3호
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• pp.637-646
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• 2011

Cho and Kim [4] and Kim [6] introduced the concept of the competition index of a digraph. Cho and Kim [4] and Akelbek and Kirkland [1] also studied the upper bound of competition indices of primitive digraphs. In this paper, we study the upper bound of competition indices of strongly connected digraphs. We also study the relation between competition index and ordinary index for a symmetric strongly connected digraph.

• 대한수학회보
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• 제50권6호
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• pp.2001-2011
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• 2013

Cho and Kim [4] have introduced the concept of the competition index of a digraph. Similarly, the competition index of an $n{\times}n$ Boolean matrix A is the smallest positive integer q such that $A^{q+i}(A^T)^{q+i}=A^{q+r+i}(A^T)^{q+r+i}$ for some positive integer r and every nonnegative integer i, where $A^T$ denotes the transpose of A. In this paper, we study the upper bound of the competition index of a Boolean matrix. Using the concept of Boolean rank, we determine the upper bound of the competition index of a nearly reducible Boolean matrix.

• 한국산림과학회지
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• 제107권2호
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• pp.193-204
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• 2018

본 연구는 국내 주요 침엽수종인 소나무, 잣나무, 낙엽송을 대상으로 거리종속 경쟁지수 모델 및 경쟁목 선정방법에 따른 최적 경쟁지수 모형을 선발하고, 수종별 간벌강도 및 입목밀도에 따른 경쟁지수 특성을 분석하고자 하였다. 사용자료는 강원도와 경상북도의 국유림 내 분포하는 소나무림, 잣나무림, 낙엽송림을 대상으로 각 2회씩 조사된 표준지 80개소의 총 240개 시험구 내 입목정보를 활용하였다. 경쟁지수가 산출된 입목 수는 수종별로 소나무 1126본, 잣나무 4093본, 낙엽송 3399본 이었다. 최적 경쟁지수 모형 선정을 위하여 흉고단면적 정수, 수고 및 지하고의 각도를 이용하여 경쟁목을 선정하는 방법을 고려하였으며, 기존 Lorimer, Martin-EK, Braathe, Heygi, Daniels 모델과 본 연구에서 제안한 Modified Daniels 모델까지 총 6가지 경쟁지수 모델을 비교하였다. 최적 모형 선정을 위한 상관분석 결과, 흉고단면적 정수 $4m^2/ha$를 이용한 경쟁목 선정방법과 Modified Daniels 경쟁지수 모델이 이용된 모형에서 가장 좋은 상관이 나타나 최종적인 모형으로써 경쟁지수가 산출되었다. 임분특성에 따른 경쟁지수를 파악한 결과, 소나무, 잣나무, 낙엽송 모두 간벌강도가 강할수록 입목밀도가 낮을수록 경쟁지수는 낮아지는 경향이 나타났다.

• 한국산림과학회지
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• 제85권3호
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• pp.539-551
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• 1996

본 연구에서는 위치종속조사가법에 의해 소나무임분에서 조사된 자료로부터 임목의 크기 및 경쟁목과의 거리를 함께 고려한 개체목차원의 거리종속경쟁지수와 전통적인 임분차원의 밀도척도를 추정하고 이들을 흉고직경생장과 비교하여 경쟁상태에 대한 설명력을 검토하였으며, 경쟁지수가 영향변수로 고려된 개체목 흉고직경생장식을 유도하였다. 경쟁목선정방법에 있어 경쟁치단각도를 30도로 설정했을 때의 경쟁지수가 흉고직경생장과 기장 높은 상관관계를 보인 반면, 경쟁구역거리는 흉고직경생장추정에 대한 경쟁지수의 설명력에 미미한 영향을 미치는 것으로 나타났다. 개체목별 거리종속경쟁지수에 근거한 대부분의 임분경쟁지수들은 임분의 경쟁상태를 비슷하게 나타내는 것으로 평가되었다. 임령과 지위지수의 영향을 배제한 상태에서의 편상관분석결과 Alemdag의 평균경쟁지수 및 상대공간지수가 흉고직경과 가장 높은 연관성을 나타냈는데, 이중 개체목의 위치를 파악하지 않고도 비교적 손쉽게 파악될 수 있는 상대공간지수가 임분의 평균흉고직경을 추정하는데는 좀더 적합한 것으로 판단되었다. 개체목차원의 거리종속 경쟁지수중에서, 지위 및 흉고직경의 영향을 배제시킨다면 Hegyi의 경쟁지수가 흉고직경생장과 가장 밀접한 영향관계에 있는 것으로 밝혀졌다. 이로부터 Hegyi경쟁지수 및 임령, 우세목수고, 개체목의 흉고직경을 영향인자로 하는 다음과 같은 흉고직경생장식을 유도하였다. $$dbh^{\prime}=3.975362676{\cdot}age^{-1.099274613}{\cdot}ho^{0.199893990}{\cdot}dbh^{0.269430865}{\cdot}HgCI^{-0.353643587}$$ 위의 식은 다른 조건이 같다면 지위지수는 흉고직경생장에 유리한 영향을 미치는 반면 임령 및 경쟁지수의 증가에 의해서는 흉고직경생장이 둔화된다는 일반생장법칙에 부합되어 흉고직경생장식으로 적합하다고 판단되며, 단목생장모델을 위한 함수식으로 활용될 수 있다.

• 대한수학회보
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• 제45권2호
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• pp.385-396
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• 2008

For a positive integer m and a digraph D, the m-step competition graph $C^m$ (D) of D has he same set of vertices as D and an edge between vertices u and v if and only if there is a vertex x in D such that there are directed walks of length m from u to x and from v to x. Cho and Kim [6] introduced notions of competition index and competition period of D for a strongly connected digraph D. In this paper, we extend these notions to a general digraph D. In addition, we study competition indices of tournaments.

• The Journal of Asian Finance, Economics and Business
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• 제8권2호
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• pp.317-328
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• 2021

This study examines the impact of bank competition and efficiency in the financial stability of the banking sector in Bangladesh. The study used the Lerner index and the Boone indicator to represent the bank competition, while the non-performing loan (NPL) and Z-score are used to represent financial stability. The secondary data were collected from the annual reports of 28 DSE listed commercial banks of Bangladesh over the period from 2011 to 2018. Using a dynamic panel GMM model, the study found the Lerner index is significantly negatively related with Z-score, which means that higher bank competition results in higher bank stability. It is also seen that higher cost efficiency results in higher bank stability. The Lerner index has negative, but insignificant impact on NPL. Similarly, using the Boone indicator, this study found that lower competition increases NPL. In terms of the Z-score, the Boone indicator found that 1 unit of increment results in decrease of the Z-score by 6.15 units. The study suggests that, as more competition results in more financial soundness, the banking industry competition should be ensured by policymakers or regulators. Banks could enhance financial stability by cost control to achieve cost efficiency as well as by improving loan-to-asset ratio.

• 산경연구논집
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• 제10권11호
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• pp.49-56
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• 2019

Purpose: Corporate social responsibility is a self-regulating business model that helps a firm be socially accountable to the public. By practicing corporate social responsibility, firms can be conscious of the kind of impact they are having on all aspects of society, including economic, social, and environmental. Corporate social responsibility activities are not directly linked to increasing corporate performance and corporate value, but rather involve spending expenses. Based on these facts, this study verifies whether the effects of corporate social responsibility activities differ depending on the firm's situation. Research design, data and methodology: This study analyzed the effect of market competition on corporate social responsibility activities using logistic regression analysis on listed companies in the KOSPI and KOSDAQ for fiscal years 2014 through 2016. In this study, market competition was measured using the Herfindahl-Herschman Index(HHI). Higher HHI value can be interpreted as a lower degree of market competition. We also measured corporate social responsibility activities using the KEJI Index published by the Korea Economic Justice Institute (KEJI). If a firm-year is included in the top 200 companies of the KEJI Index, it is classified as a good corporate social responsibility activity firm. Results: We find that companies in less competitive market were not included in the KEJI Index. This result indicates that firms in the market with lower market competition perform less corporate social responsibility activities that incur costs. An additional analysis showed that there was a significant negative relationship between the market competition and the corporate social responsibility activity scores published by the KEJI Index. These result adds robustness to the result of the hypothesis that firms that have a monopolistic place in the market practice passive corporate social responsibility activities. Conclusions: The results show that managers of a firm in the lower market competition have a lower incentive to use limited resources for projects that are not directly related to revenue. The results of this study imply that corporate social responsibility activities vary according to the position of the business. Therefore, this study suggests that market investors should consider the degree of competition in the market when they evaluate corporate social responsibility activities.

• 대한치과의사협회지
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• 제54권12호
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• pp.971-984
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• 2016

The increase rate of dentists' competition is very fast at metropolitan areas in South Korea. We compare metropolitan and rural parameters to investigate the relation between competition and revenue variation. The competition and revenue variables of 73 metropolitan and 75 rural areas were calculated from 2010 Census of Service Industry microdata which include non-insurance revenues of dental clinics. Independent sample t-test results showed that the level of competition among dental clinics in metropolitan areas is higher. The lowest and the low ranked revenues are higher in rural areas. The highest and the average revenues are higher in metropolitan areas. But, 25 percentile and median revenues has no significant difference between two areas. Simple log linear regression results showed that the number of clinics could explain the distribution of revenues in both areas better than the density of active dentists and Herfindahl-Hirschman index. In the areas with many clinics have high maximum and average revenues and low minimum revenues. The increasing rate of maximum revenues is higher in metropolitan areas though the decreasing rate of minimum revenues is higher in rural areas. Metropolitan areas have higher Gini coefficients than rural areas, but the increasing rate of Gini coefficients is lower than rural areas. Findings from this study are useful reference when the dentists select the opening areas. One is that the median revenues between metropolitan and rural areas have no significant difference. The other is that the rural areas ensure the more stable and uniform revenues. The results would help to relieve the consumptive competition among dentists and to achieve the distributional efficiency of dental human resources.

• 통상정보연구
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• 제7권4호
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• pp.351-365
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• 2005

Korean auto mobile industry has been contributed to development on national economy for last 30 years. Especially, The fact is that latest increasement of Korean automobile selling is worthy of notice in U.S. market which is the biggest automobile market of the world. But development of automobile industry unattainable nothing of helping of auto parts industry. So, when we discuss about growth of automobile industry, we also have to consider role of auto parts industry at the same time. The purpose of this study was to analyze exporting competition of Korean auto parts in U.S. market by using Index of Export Bias and Market Comparative Advantage Index. For attaining the purpose of study, we classified the Korean auto parts which exported to U.S. market and the world by using the six units classification of the Harmonized System(HS). Also we measured Index of Export Bias and Market Comparative Advantage Index. Analyzing period was 1998-2004. The results of Index of Export Bias indicated that HS Code No. 8708.50, 8708.91 represented over 3 numerical value and 8708.92, 8708.60, 8708.39, 8708.29 represented over 2 numerical value. Additional results indicated that the Korean auto parts which gained exporting competition in the U.S. market were HS Code No. 8708.70, 8708.93, 8708.92. The products which will have exporting competition in the U.S. market would be HS Code No. 8708.99,