Detecting community structure in complex networks using an interaction optimization process

Kim, Paul,Kim, Sangwook Elsevier 2017 PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIO Vol.465 No.-

<P><B>Abstract</B></P> <P>Most complex networks contain community structures. Detecting these community structures is important for understanding and controlling the networks. Most community detection methods use network topology and edge density to identify optimal communities; however, these methods have a high computational complexity and are sensitive to network forms and types. To address these problems, in this paper, we propose an algorithm that uses an interaction optimization process to detect community structures in complex networks. This algorithm efficiently searches the candidates of optimal communities by optimizing the interactions of the members within each community based on the concept of greedy optimization. During this process, each candidate is evaluated using an interaction-based community model. This model quickly and accurately measures the difference between the quantity and quality of intra- and inter-community interactions. We test our algorithm on several benchmark networks with known community structures that include diverse communities detected by other methods. Additionally, after applying our algorithm to several real-world complex networks, we compare our algorithm with other methods. We find that the structure quality and coverage results achieved by our algorithm surpass those of the other methods.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Improving the technique for detecting community structures is important for understanding and controlling complex networks. </LI> <LI> Most community detection methods have a high computational complexity and are sensitive to network forms and types. </LI> <LI> We propose an algorithm that uses an interaction optimization process to detect community structures in complex networks. </LI> <LI> We find that the structure quality and coverage resulting from our algorithm surpass the results of other methods. </LI> </UL> </P>

Plant Community Structure from the Jilmoi Wetlands to the Donghae Observatory, Baekdudaegan Mountains

( Jin Woo Choi ),( Kyung Won Kim ),( Jung Hun Yeum ),( Won Seok Hwang ) 한국환경생태학회 2015 한국환경생태학회지 Vol.29 No.2

This study aims to investigate the characteristics of the vegetation structure in the sectin stretching between the Jilmoi wetlands and the Donghae Observatory and to set the criteria for the basic data for a management plan including restoration afterwards. 12 plots(10 m×40 m, 20 m×20 m) were set up to analyse the vegetation structure. The analysis of the classification by TWINSPAN and ordination by DCA, importance percentage and property, distribution of diameter of breast height, growth increments of major woody species, species diversity and the physicochemical properties of soil were all analyzed. Vegetation classes were divided into 3 communities, which are community Ⅰ(Pinus densiflora community), community Ⅱ(Quercus mongolica community) and community Ⅲ(Quercus mongolica-Tilia amurensis community). The P. densiflora community declined when competing with Q. mongolica and Fraxinus rhynchophylla and Q. mongolica competed with T. amurensis on an understory layer in Q. mongolica community. Q. mongolica competed with T. amurensis on both canopy and understory layers in Q. mongolica-T. amurensis community. P. densiflora declined and it was assumed to succeed to F. rhynchophylla or T. amurensis through Q. mongolica based on the importance percentage and distribution of the diameter of the breast height of small and middle sized trees. The age of P. densiflora was between 47 to 51 years old and Q. mongolica was 61years old. T. amurensis was 61 years old and the growth of Q. mongolica slowed a little. As the result of Shannon``s index of species diversity, community Ⅰranged from 0.9578 to 1.1862, community Ⅱranged from 0.7904 to 1.2286 and community Ⅲranged from 0.8701 to 1.0323. The contents of organic matter and cation were low compared to uncultivated mountain soil and it were analysed to be inappropriate for tree growth.

지역사회 권력구조에 대한 실증연구 분석과 전망

이우권(Lee Woo-Kwon) 한국정치정보학회 2007 정치정보연구 Vol.10 No.1

지역사회 권력구조란 일정 지역사회의 범위 내에서 지역의 변화를 창도할 수 있는 세력의 주체 즉, 지역사회 권력엘리트 사이에 형성되어 있는 권력배분 양태 그리고 그러한 권력엘리트간의 권력적 상호작용을 의미한다. 이 연구는 외국 및 한국에서 이루어진 기존의 지역사회 권력구조에 관한 실증적 연구들을 체계적으로 분석하고 이를 바탕으로 앞으로 진행될 것으로 전망되는 지역사회 권력구조 연구의 방향성을 제시하는 데 있다. 한국에서 진행된 지역사회 권력구조에 대한 연구들은 전반적으로 아직 초보적인 단계와 탐색적 수준에 머무르고 있고, 연구자의 관심과 제약요인에 의해 연구대상 지역에 대한 선정 역시 개별적으로 진행되어 왔으며, 이러한 선별적 연구들의 결과 해석은 지역사회 권력구조에 대한 이론정립 문제보다는 각 연구에서 활용된 방법론 중심의 논쟁이 주를 이루고 있다. 따라서 앞으로 진행될 지역사회 권력구조에 관한 연구들은 기존의 연구들이 내포하고 있는 한계점 즉, 지역사회 권력구조에 관한 기초가 되는 이론 및 방법론 배경에 관한 충분한 연구와 적용, 지역사회 권력구조 자체에서 발현되는 것으로 식별된 지도자들 사이에서 이루어지는 상호작용의 총합으로서 구체적인 관계망 분석 등을 충분히 실현해야 할 것이다. Community power structure menas power distribution shape in community power elite and power interaction of community power elite within a community. The purpose of this study is suggest direction and prospect of future community power structure study base on preceding community power structure study in foreign and korea. Community power structure study in future should fill up a soft spots of preceding community power structure study. first, A study thoroughly investigate and adaptation theory and methodology base on community power structure study. second, A study carry into analysis of power interaction and relation network among community power elite manifested in community power structure.

새마을금고의 건전성 제고방안

노미리 한국경제법학회 2023 경제법연구 Vol.22 No.2

새마을금고 사태가 주기적으로 발생하는 것은 새마을금고의 지배구조가 취약하고, 내부통제에 문제가 있다는 것이다. 이 글에서는 새마을금고의 건전성 제고방안과 관련하여 새마을금고의 지배구조 개선방안과 감독체계 개편을 다루었다. 새마을금고의 지역금고와 중앙회는 공통적으로 이사회, 총회(대의원회)라는 기구가 있고, 감사위원회는 중앙회에만 있는 조직이다. 새마을금고에서 중앙회장의 권한은 막강한 바, 이를 견제하기 위해서는 이사회, 총회(대의원회), 감사위원회의 역할이 중요하다. 감사위원회에 관한 내용은 2019년 감사위원회의 독립성을 제고하기 위하여 개정되었는바, 새마을금고의 지배구조 개선방안과 관련하여 이 글에서는 이사회와 총회의 역할 강화 방안을 검토하였다. 첫째, 이사회의 역할을 강화하기 위해서는 이사회의 독립성 및 전문성이 강화되어야 한다. 그러기 위해 상근이사의 자격 요건을 강화하고 임원의 결격사유를 강화하는 등 이사의 자격 요건을 강화할 필요가 있다. 또한, 성과평가 대상 확대를 통한 이사의 전문성을 강화해야 한다. 또한 임원진의 책임 강화를 위해 내부통제기준을 강화해야 하는데, 그 방안으로 내부통제기준 위반 시 제재처분 기준의 수위를 상향해서 조정하는 방안이 있다. 또한, 내부통제규정 중 지속적으로 문제가 되는 이해상충행위인 쪼개기 대출, 사적 거래를 법률로 상향 조정한다면 임직원의 내부통제기준에 대한 인식 제고에 도움이 될 것이다. 둘째, 총회의 역할이 강화되려면 총회가 활성화되어야 한다. 총회가 활성화되기 위해서는 회원의 참여권이 강화되어야 하며, 참여권의 전제가 되는 회원의 알 권리가 보장되어야 한다. 회원의 알 권리 보장을 위해서 새마을금고의 정보제공의무와 공시의무가 강화되어야 한다. 또한 회원의 참여권 강화를 위해서는 회원이 전자적 방법으로 서류를 제공받거나 의결권을 행사할 수 있도록 새마을금고법을 개정할 필요가 있다. 또한 금고의 회원이 적극적으로 의결권을 행사할 수 있도록 사전에 총회참고서류 등이 제공되어야 한다. 다음으로 새마을금고의 감독체계 개편과 관련하여 새마을금고의 주무부처를 금융위원회로 변경해야 한다. 주무부처 변경은 새마을금고의 내부통제와 관련이 있다. 행정안전부의 주된 업무가 금융 업무가 아니라는 점, 행정안전부의 중앙회에 대한 정기종합 감사가 격년으로 이루어지는 점에 비추어 봤을 때, 현행 감사방식이 새마을금고의 부실을 사전에 예방할 수 있는 방법이라고 보기는 어렵다. 그러므로 새마을금고의 주무부처를 금융위원회로 변경할 필요가 있다. The periodic occurrence of Community Credit Cooperative’s problem is attributed to its weak governance structure and internal control issues. This article discusses ways to enhance the soundness of Community Credit Cooperatives and focuses on improving its governance structure and supervisory system. Both the regional credit cooperatives and the federation of Community Credit Cooperatives (hereinafter ‘the federation’) have a common body called the board of directors and the general assembly (representative assembly), while the audit committee is unique to the federation. The authority of the chairman of the federation is quite strong, making it crucial to have the roles of the board of directors, general assembly, and audit committee strengthened to check this authority. Regarding the audit committee, it was revised in 2019 to enhance its independence. Therefore, this article discuss ways to strengthen the roles of the board of directors and the general assembly in relation to improving Community Credit Cooperative’s governance structure. To strengthen the role of the board of directors, its independence and expertise need to be enhanced. This can be achieved by reinforcing the qualifications for full-time directors and tightening the disqualification criteria for executives. Furthermore, enhancing the expertise of directors through the expansion of performance evaluations is necessary. Additionally, to strengthen the responsibility of executives, the internal control standards should be reinforced, and one possible measure is to adjust the level of sanctions for violations of internal control standards upward. Addressing persistent issues in the internal control regulations, such as split loans and private transactions, through being prescribed in legislation could help improve officers’ and employees' awareness of internal control standards. To strengthen the role of the general assembly, it needs to be activated. To activate the general assembly, this requires empowering the members' participation rights, and the rights of members to know, which are the premise of the rights to participate, must be guaranteed. To ensure the guarantee of members' rights, Community Credit Cooperative’s obligations to provide information and disclose information must be strengthened. Additionally, to enhance members' participation rights, there is a need to revise the Community Credit Cooperatives Act to allow members to receive documents electronically and exercise their voting rights electronically. Moreover, to enable active exercise of voting rights by members, pre-meeting reference documents for the general assembly should be provided. Next, regarding the reorganization of Community Credit Cooperative’s supervisory system, it is necessary to change the responsible agency for Community Credit Cooperatives to the Financial Services Commission (hereinafter ‘FSC’). The change of the responsible agency is related to the internal control of Community Credit Cooperatives. Considering that the main business of the Ministry of Public Administration and Security (hereinafter ‘MPAS’) is not in finance and that the regular comprehensive audits of the federation by the MPAS are conducted every two years, the current audit method may not be an effective means of preventing Community Credit Cooperatives’ insolvency in advance. Therefore, there is a need to change the responsible agency for Community Credit Cooperatives to the FSC.

Plant Community Structure from the Jilmoi Wetlands to the Donghae Observatory, Baekdudaegan Mountains

Choi, Jin-Woo,Kim, Kyung-Won,Yeum, Jung-Hun,Hwang, Won-Seok Korean Society of Environment and Ecology 2015 한국환경생태학회지 Vol.29 No.2

This study aims to investigate the characteristics of the vegetation structure in the sectin stretching between the Jilmoi wetlands and the Donghae Observatory and to set the criteria for the basic data for a management plan including restoration afterwards. 12 plots($10m{\times}40m$, $20m{\times}20m$) were set up to analyse the vegetation structure. The analysis of the classification by TWINSPAN and ordination by DCA, importance percentage and property, distribution of diameter of breast height, growth increments of major woody species, species diversity and the physicochemical properties of soil were all analyzed. Vegetation classes were divided into 3 communities, which are community I (Pinus densiflora community), community II (Quercus mongolica community) and community III (Quercus mongolica-Tilia amurensis community). The P. densiflora community declined when competing with Q. mongolica and Fraxinus rhynchophylla and Q. mongolica competed with T. amurensis on an understory layer in Q. mongolica community. Q. mongolica competed with T. amurensis on both canopy and understory layers in Q. mongolica-T. amurensis community. P. densiflora declined and it was assumed to succeed to F. rhynchophylla or T. amurensis through Q. mongolica based on the importance percentage and distribution of the diameter of the breast height of small and middle sized trees. The age of P. densiflora was between 47 to 51 years old and Q. mongolica was 61years old. T. amurensis was 61 years old and the growth of Q. mongolica slowed a little. As the result of Shannon's index of species diversity, community I ranged from 0.9578 to 1.1862, community II ranged from 0.7904 to 1.2286 and community III ranged from 0.8701 to 1.0323. The contents of organic matter and cation were low compared to uncultivated mountain soil and it were analysed to be inappropriate for tree growth.

연계중심 군집화를 통한 거대도시 분석

한이철 ( Yicheol Han ),이정재 ( Jeongjae Lee ),임상봉 ( Sangbong Im ) 한국농공학회 2011 한국농공학회 학술대회초록집 Vol.2011 No.-

The mega-region rose as new economic unit. It is defined by connected networks of metropolitan areas, contiguous “functional urban regions” each with an employment core and a commuting ring, or integrated sets of cities and their surrounding suburban hinterlands across which labor and capital can be reallocated at very low cost. Even though those importance of mega-regions and strong relationship with commuting data, there are not widely used methods for detecting the boundary of them except night-time lights. The mega-region is the spatial structure organized by commuters among regions, and commuting is presented by network form. Therefore large communities of commuting network can be regarded as mega-regions, and we can use community detecting method to analysis the mega-regions. Many methods have been proposed to uncover the community structure of networks. Among them the hierarchical clustering method using dendrogram is used as the principal technique to detecting communities under the assumption that every node belongs to only one community. That method, however, does not allow for overlapping communities of nodes, although overlapping as well as hierarchy is usually regarded to the crucial features of communities in many real networks. Overlapping means that nodes may simultaneously belong to more than one group. Thus community structure cannot project the relationship among overlapped groups. To capture hierarchy and overlapping concepts, link community was proposed. They redefined community as group of links rather than nodes and showed that link community method reconciled the antagonistic two network structure concepts. In this paper we evolve link community method for detecting mega-regions and analyze the characteristics of detected regions. Firstly, we propose a link vector in order to present directed and weighted network. A directed and weighted network is described as n by n matrix. Here a row (or column) of matrix is type of a vector. A link and its connected situations can be also described as vector form which contains the information about connected nodes and their weights. Then we suggest new similarity formula which means the angle between link vectors using dot product. If a link is a vector, degree of parallel between two vectors in n-dimensions implies similarity. Using dot product and trigonometric functions we can get the degree of parallel as angle between them. Finally, we apply the evolved link community model to commuting network data to detect and analyze mega-regions.

Plant Community Structure from the Jilmoi Wetlands to the Donghae Observatory, Baekdudaegan Mountains

최진우,김경원,염정헌,황원석 한국환경생태학회 2015 한국환경생태학회지 Vol.29 No.2

This study aims to investigate the characteristics of the vegetation structure in the sectin stretching between the Jilmoi wetlands and the Donghae Observatory and to set the criteria for the basic data for a management plan including restoration afterwards. 12 plots(10 m×40 m, 20 m×20 m) were set up to analyse the vegetation structure. The analysis of the classification by TWINSPAN and ordination by DCA, importance percentage and property, distribution of diameter of breast height, growth increments of major woody species, species diversity and the physicochemical properties of soil were all analyzed. Vegetation classes were divided into 3 communities, which are community Ⅰ(Pinus densiflora community), community Ⅱ(Quercus mongolica community) and community Ⅲ(Quercus mongolica-Tilia amurensis community). The P. densiflora community declined when competing with Q. mongolica and Fraxinus rhynchophylla and Q. mongolica competed with T. amurensis on an understory layer in Q. mongolica community. Q. mongolica competed with T. amurensis on both canopy and understory layers in Q. mongolica-T. amurensis community. P. densiflora declined and it was assumed to succeed to F. rhynchophylla or T. amurensis through Q. mongolica based on the importance percentage and distribution of the diameter of the breast height of small and middle sized trees. The age of P. densiflora was between 47 to 51 years old and Q. mongolica was 61years old. T. amurensis was 61 years old and the growth of Q. mongolica slowed a little. As the result of Shannon's index of species diversity, community Ⅰranged from 0.9578 to 1.1862, community Ⅱ ranged from 0.7904 to 1.2286 and community Ⅲ ranged from 0.8701 to 1.0323. The contents of organic matter and cation were low compared to uncultivated mountain soil and it were analysed to be inappropriate for tree growth.

Plant Community Structure from the Jilmoi Wetlands to the Donghae Observatory, Baekdudaegan Mountains

Jin-Woo Choi,Kyung-Won Kim,Jung-Hun Yeum,Won-Seok Hwang 한국환경생태학회 2015 한국환경생태학회지 Vol.29 No.2

This study aims to investigate the characteristics of the vegetation structure in the sectin stretching between the Jilmoi wetlands and the Donghae Observatory and to set the criteria for the basic data for a management plan including restoration afterwards. 12 plots(10 m×40 m, 20 m×20 m) were set up to analyse the vegetation structure. The analysis of the classification by TWINSPAN and ordination by DCA, importance percentage and property, distribution of diameter of breast height, growth increments of major woody species, species diversity and the physicochemical properties of soil were all analyzed. Vegetation classes were divided into 3 communities, which are community Ⅰ(Pinus densiflora community), community Ⅱ(Quercus mongolica community) and community Ⅲ(Quercus mongolica-Tilia amurensis community). The P. densiflora community declined when competing with Q. mongolica and Fraxinus rhynchophylla and Q. mongolica competed with T. amurensis on an understory layer in Q. mongolica community. Q. mongolica competed with T. amurensis on both canopy and understory layers in Q. mongolica-T. amurensis community. P. densiflora declined and it was assumed to succeed to F. rhynchophylla or T. amurensis through Q. mongolica based on the importance percentage and distribution of the diameter of the breast height of small and middle sized trees. The age of P. densiflora was between 47 to 51 years old and Q. mongolica was 61years old. T. amurensis was 61 years old and the growth of Q. mongolica slowed a little. As the result of Shannon's index of species diversity, community Ⅰranged from 0.9578 to 1.1862, community Ⅱranged from 0.7904 to 1.2286 and community Ⅲranged from 0.8701 to 1.0323. The contents of organic matter and cation were low compared to uncultivated mountain soil and it were analysed to be inappropriate for tree growth.

Comparative study of changes in reaction profile and microbial community structure in two anaerobic repeated-batch reactors started up with different seed sludges

Kim, J.,Lee, S.,Lee, C. Elsevier Applied Science 2013 Bioresource technology Vol.129 No.-

Microbial community structure and dynamics were examined in two anaerobic reactors run in repeated-batch mode to treat whey permeate. Despite being started up using different seeding sources, the reactors showed generally similar reaction patterns and performances. During the repeated-batch operation for three cycles, the overall reaction rate increased with the increase in the initial population size of both bacteria and methanogens over cycles. Clostridium- and Methanospirillum-related microorganisms were likely the main acidogenic and methanogenic populations, respectively, in both reactors. Bacterial community structure shifted dynamically over cycles, while little change was observed in methanogen community structure throughout the operation. This means that the changes in bacterial community structure changes had little influence on the formation and evolution of methanogen community structure in the reactors. The increased methanogenesis rate with cycles seemed therefore more likely due to the effect of the increase in methanogen abundance rather than the alteration of community structure.

‘역설적 공간’으로서의 학습공동체: 후기구조주의 공간 관점에서 학습공동체 재사유하기

최근정 ( Choi Kunjung ),최선주 ( Choi Seonjoo ) 인하대학교 교육연구소 2019 교육문화연구 Vol.25 No.3

이 연구의 목적은 기존 학습공동체 논의에 대한 비판적 성찰과 후기구조주의 공간 관점에서 학습공동체 재사유 방향을 탐색하는 것이다. 문헌분석을 통해 학습공동체 논의의 구체적인 특징을 분석하였고, 특이성, 유동성, 위치성으로 특징 지워지는 후기구조주의 공간 관점에서 학습공동체에 대한 3가지 재사유 방향을 제시하였으며, 이 새로운 개념의 학습공동체를 ‘역설적 공간으로서의 학습공동체’로 명명하였다. 첫째, ‘작품이 아닌’ 학습공동체: 공동체중심에서 특이성의 학습공동체성으로 둘째, ‘사이공간’을 창출하는 학습공동체: 경계만들기에서 연결접속의 배치로 셋째, ‘공간정치’로서 학습공동체: 장소성에서 위치성으로 학습공동체 재사유하기를 제안하였다. 이 연구는 공동체에 대한 경직된 사유에서 탈피하여 학습공동체의 다양한 존재 방식과 역동을 보다 입체적으로 파악할 수 있도록 학습공동체 논의를 확장한다는 점에서 의미가 있다. Learning community has long been regarded as an ideal concept in lifelong learning. Though the concept has evolved gradually according to the social trends― ranging from learning circles, learning organizations, and learning villages, to learning communities― Learning community has been noted as a key mechanism of the learning society. This paper raised questions on current discourses of learning community, which are based on rigid ideas of community and fail to fully capture the dynamics of learning community. Thus, the study analyzed the characteristics of existing learning community discourses critically and suggested a new thinking flux of the post-structuralism’s space perspectives, characterized by ‘singularity’, ‘fluidity’, and ‘positionality’. The new concept of learning community that encompasses these three characteristics is referred to as ‘learning community as a paradoxical space’. (1) a learning community rather than a work as a learning community with a ‘singularity’, (2) a learning community that creates ‘in-between-spaces’ from the creation of boundaries to the placement of connections, and (3) a learning community as ‘spatial politics’ with positionality. This study is meaningful in that it critically reflects learning community discourses and suggests more stereoscopic understanding of its aspects and dynamics.