• Proceedings of the Korea Inteligent Information System Society Conference
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• 2006.06a
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• pp.344-353
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• 2006

Nowadays many people participate in online communities for information sharing. But most recommender systems are designed for personalization of individual user, so it is necessary to develop a recommendation procedure for group users, such as participants in online communities. This paper proposes a group recommender system to recommend books for group users in online communities. For such a purpose, we suggest a group recommendation procedure consisting of two phases. The first phase is to generate recommendation list for 'big user' using collaborative filtering, and the second phase is to remove irrelevant books among previous list reflecting the preference of each individual user. The procedure is explained step by step with an illustrative example. And this procedure can potentially be applied to other domains, such as music, movies and etc.

• The Korean Journal of Ecology
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• v.22 no.3
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• pp.119-129
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• 1999

The bryophyte communities on the forest floor of the mixed coniferous and deciduous broad-leaf forest and the evergreen coniferous forest of cool temperate and subalpine zones in Mts. Taebaek, Odae and Sulak of Tabaek Range were investigated from. the numerical and phytosociological viewpoints. As a result, four bryophyte communities were recognized there, considering the species composition of vascular vegetation; A. Thuja koraiensis-Abies nephrolepis/Taxus caespitosa-Pinus pumila/Hylocomium splendens-Pleurozium schreberi community, B: Sasamorpha borealis-Abies nephrolepis/Plagiomnium cuspidatum- Aulacomnium heterostichum community, C. Abies holophylla-Abies nephrolepis/Thuidium recognitum-Trachycystis immarginata cristatus community, D. Meehania urticifolia-Abies nephrolepis/Hylocomiopsis ovicarpa-Taxiphyllum aomoriense community. Among these, the community A was distributed in higher altitudes and characterized by the species group of the holarctic elements, e.g. Hylocomium splendens, Pleurozium schreberi, Dicranum majus, etc. limited in subarctic; subalpine and arctic; alpine zones and was confirmed as synusies of the Thujo-Abietetum nephrolepidis Song 1991 and Taxo-Pinetum pumilae Song 1985 belonging the Vaccinio-Piceetea Br.-Bl. 1939. In contrast the communities B, C and D were distributed in the mixed coniferous and deciduous broad-leaf forest of lower altitudes and characterized by the elements of the cool temperate; montane zone. They were confirmed as synusies belonging to the Corylo-Quercetum mongolicae Song 1988. By the result of the numerical syntaxonomical analysis such as cluster analysis, interspecific association, PCA, the communities were largely divided into the two types. The two types coincided with the community units or the diagnostic species of the bryophyte communities of the subalpine zone and the montane zone, respectively. Also the analysis revealed that the division of the above two forest zones are justifiable. Up to date many investigator have described the coniferous forest distibuted above 1000m in Taebaek mountains as the forest vegetation of subalpine zone. However, from the results of the present study, the boundary of the mixed forest and the true subalpine coniferous forest was elucidated to be ca. 1,500 m phytosociologically. Species richness was the highest in the community A, and the other four communities showed a similar species richness.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.11a
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• pp.27-32
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• 2009

Since the cohousing idea, originated in Northern Europe, was introduced in the U.S. by architects Kathryn McCamant and Charles Durrett in the early 1980s, there are recently the largest number of cohousing communities and rapidly expanded in the U.S. So, it is necessary to appreciate the cohousing communities developed in U.S. In this study, we investigated the physical characteristics of cohousing and the methods of its residents' participation by means of a case study on cohousing communities in U.S. and suggested the future direction of the cohousing community. Also, this work could be exploited when the cohousing is introduced to Korea. At first, the general status and characteristics of U.S cohousing was explored using diverse sources such as literature, paper and Web site. And then, the direct visit survey was used to obtain the more exact and specific data about physical aspects and residents' participation in each community. We found that cohousing communities were mostly located in the urban and Rural area, which was founded in the 1990s, and new communities continue to be created in the U.S. Typically, the number of households is from 20 to 30 in one community. The land is generally owned by the community itself and its size is within 10 acres. Communities usually serve optional group meals in the common house at least two or five times a week. Each member's income is separated and the community members should take care of their common properties. The leader of community does not exist and most communities don't have the organization of community members. All cohousing communities use consensus as the basis for group decision-making.

• Journal of the Korean housing association
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• v.22 no.2
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• pp.11-20
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• 2011

Since the cohousing idea, originated in Northern Europe, was introduced in the U.S. by architects Kathryn McCamant and Charles Durrett in the early 1980s, there are recently the largest number of cohousing communities and rapidly expanded in the U.S. So, it is necessary to appreciate the cohousing communities developed in U.S. In this study, we investigated the physical characteristics of cohousing and the methods of its residents' participation by means of a case study on cohousing communities in U.S. and suggested the future direction of the cohousing community. Also, this work could be exploited when the cohousing is introduced to Korea. At first, the general status and characteristics of U.S cohousing was explored using diverse sources such as literature, paper and Web site. And then, the direct visit survey was used to obtain the more exact and specific data about physical aspects and residents' participation in each community. We found that cohousing communities were mostly located in the urban and Rural area, which was founded in the 1990s, and new communities continue to be created in the U.S. Typically, the number of households is from 20 to 30 in one community. The land is generally owned by the community itself and its size is within 10 acres. Communities usually serve optional group meals in the common house at least two or five times a week. Each member's income is separated and the community members should take care of their common properties. The leader of community does not exist and most communities don't have the organization of community members. All cohousing communities use consensus as the basis for group decision-making.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.351-351
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• 2017

Arbuscular mycorrhizal fungi (AMF) are particular soil fungi that benefit many crops and require a symbiosis with plant roots to survive. In our previous study, there was a positive correlation between AMF root colonization and soybean grain yield in a four-year consecutive winter cover crop-soybean rotational system without phosphorus fertilizer. It is suggested that higher AMF root colonization can be a better solution for improving soybean growth and grain yield in P-limited soil. Our purpose in this study was to test the hypothesis that a P application is the main factor improving soybean growth, P nutrition and grain yield, and the benefit from AMF to soybean P uptake and growth in a P-limited soil. Impact of a P application on AMF root colonization and communities in soybean roots and their potential contribution to soybean growth and P nutrition under a five-year P-unfertilized crop rotational system were investigated over two-years. In this study, four cover crop treatments included 1) wheat (Triticum aestivum); 2) red clover (Trifolium pratense); 3) rapeseed (Brassica napus); and 4) fallow in the crop rotation. The amount of triple superphosphate as a P fertilizer applied rate after cultivation of cover crops was 120 and $360k\;ha^{-1}$ in 2014 and 2015, respectively. Soybean roots were sampled at full-flowering and analyzed for AMF communities using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and quantitative real-time PCR (qPCR) techniques. The AMF root colonization in the soybean roots at full bloom stage was significantly influenced by cover crop and P application throughout the two-year rotation. The two-year rotation of different cover crops or fallow impacted the molecular diversity of AMF communities colonizing roots of soybean. Redundancy analysis (RDA) indicated that AMF communities colonizing roots of soybean were significantly different among cover crop rotations. The AMF communities colonizing roots of soybean were clearly influenced by a P application in the two-year trial. Moreover, a P application may have positively impacts on the AMF communities under P-deficit soil due to the continuous cover crop-soybean rotational system without a P fertilizer.

• Journal of Plant Biology
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• v.9 no.1_2
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• pp.7-16
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• 1966

In order to determine the factors related to site quality, 13 areas of Larch growing in the Kwangung and its vicinity forest as sample plots, were examined. Sample plots included various site classes as well as age classes. Three were divided into two groups (major and minor trees). Average height of dominant trees was determined through messurement of 5 to 6 dominant tree in each sample plots. Average height of dominant 30 year-old trees was the basis for site index. A Standard Yield Table for the larch produced in Kwangnung forest was made by various data, which included age class 5, ranging from 10 to 45 years. The relationship of the height of the trees, the site conditions, and ground vegetation are investigated in this paper. The site indexes of 40 forest class age in 28-B and 28-G forest classes of the larch associations for ground vegetation had comparatively rarge differences due to the sampled areas. The relation of the direction of forest communities to the height and the diameter of the tree shwoed that its communiteis of northest and northwest parts appeared higher valueof the height and the diameter. The diameter and the height of trees were closely realted to each other. The samller the occupied area per tree and the smaller the average distance among trees, the more density was increased. The larger the density was the lower height of the trees. In the ground vegetation of the larch communities, there seems to be a definite correlation between the height of trees and the occupied area per tree or the average distance among the trees. The height of trees and site index of two larch communities were as follow: 28-B forest class site index 20.8, height 24.0m, 28-G forest class site index 18.4, height 20.9m. The ground layer was analyzed by the method of Quadrat(20/20sq. cm) with an interval of 1M. It set up 40 Quadrats of the larch communiteis. The community structure of the ground vegetation of two larch was analyzed, and important value was calculated and then evaluated. The ground vegetation under the larch had developed Burmannii Beauv stratal society below the 28-B and 28-G the forest class. Accordingly, the first important value of Burmannii Beauv was found in two ground vegetation below the larch. Therefore, this species could be quantitatively considered as the forest indicator species. Common species of each community appeared 18 species out of 34 species in the ground vegetation under two larch communities. The ground vegetation of the 28-B forest class showed more than that of the 28-G forest class. the similarity of the ground vegetation was measrued by the Frequency Index Community Coefficient. The differences between the associations were lcearly manifested by the ground vegetation tested by Gleason's Frequency Index of Community Coefficient for the analysis of each stratal society of all associations. According to F.I.C.C. the ground vegetation under two larch(28-B and 28-G) forest classes showed higher value. An investigation into the relationship of physical and chemical properties of soil and site was considered the next step to be taken in the study of the larch site classification.

• The Korean Journal of Ecology
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• v.13 no.2
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• pp.149-163
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• 1990

Two distinct spider communities were studied in the crowns and ground surfaces of pine plantations at Mt. Ungilsan, Kyonggi-do using pitfall traps and knock-down by spraying of an insecticide (D.D.V.P.) to sample spiders. There were 34 species of 11 families in the ground community and 41 species of 15 families in the crown community, with only 9 species being collected in both. Wandering spiders comprised 78.5% of the crown community and 90.8% of the ground community. Guild abundance and the most abundant families were distinctly different in the two habitats: agile hunters (Salticidae:32.4%) and nocturnal hunters (Clubionidae:19%) in the crown, runners (Lycocidae:32.8%) and nocturnal hunters (Gnaphosidae:31.2%) in the ground. Dominant species were Clubiona jucunda (Karsch) and Mymarachne japonica (Karsch) in the crown, while in the ground they were Pardosa laura Karsch and Gnaphosa silvicola. Species diversity(H ) had peaks in May, July and November in the ground community, while in the crown community peaks were in June and September. The seasonal trends of species diversity (H ) were due mainly to differences in the number of species and the numbers of individuals collected at each sample date rather than to differences in equitability among species. Spier guilds and dominant species have different seasonal patterns based on the temporal differences in prey availability in the two communities and the reduction of temporal overlap.

• Korean Journal of Organic Agriculture
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• v.16 no.1
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• pp.91-113
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• 2008

This study ultimately aims at suggesting the improvements for community development policy in Korea. In order to do so, this carried out field surveys for two rural villages and tried to find out the current institutional situation of rural villages. Reviewing conceptual debates on rural, village, community and organisation theory, it sets up a typology of four groups as follows: voluntary expressive group, involuntary expressive group, voluntary instrumental group, and involuntary instrumental group. Based on this typology, this study conducted field surveys for two rural villages; Pyeongchon-Ri in Chungnam and Noolmi-Ri in Kyoungbuk. From the analysis on the field surveys, it finds some features on Korean rural groups. First, the residents in rural villages have very strong identity for their living areas. Second, the number of rural groups are tend to decrease recently. Third, the actions of instrumental groups are determined by the organisations operating nearby. Fourth, the function of groups within rural villages only carry out some village festivals, but other friendly relationship among rural residents are expanded out to wider areas called Myeon. As a result, this study suggests that we should recognize the diversity in rural communities in Korea and deals with them in different ways of public policies.

• Journal of Agricultural Extension & Community Development
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• v.9 no.1
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• pp.87-100
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• 2002

The purpose of this study were to compare the community attachment between rural and urban communities, and suggest directions for community development plans of rural and urban communities in Korea. The data for this study were collected from two communities(n=285), one from Gochang representing rural community, located in Jeonbuk province(n=142), and the other from Suwon city representing urban community located in Gyunggi province(n=143), utilizing questionnaire. The major finding of this study were as follows; 1) Community attachment was significantly higher in community than in urban community, and the linear development model was more appropriate to explain the results of the study. 2) Community attachment appeared to be significantly related to social bonds, community participation, social trust, community economical activities, and social and cultural environment. 3)In general, determinants such as number of acquaintances, price of cultural heritages of residence, trust for local government, good traffic environment, job satisfaction, etc. explained 55.5% in rural and urban communities.

• Asia pacific journal of information systems
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• v.16 no.2
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• pp.183-203
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• 2006

Firms are increasingly adopting online communities-of-practice (CoPs) with strong managerial support in hopes of promoting knowledge sharing and creation within the organization. Excessive managerial concern and sponsoring, however, could harm the spontaneity of CoP participants, which is one of the pivotal characteristics of virtual communities, and in the end, have negative impact on their smooth operation. In this regard, this study examines the factors which affect the stimulation of CoPs and explores the difference in their operating mechanisms under two differing organizational structural settings by the existence of a sponsor. By analyzing 133 samples of CoPs in a globally leading company, this study found that the existence of a sponsor designated by the organization, has serious influence on the working of CoPs, That is, leaders' enthusiasm and the level of off-line activities are critical factors for the stimulation of CoPs which have no sponsor, while in case of CoPs that have their sponsors, neither leaders' enthusiasm nor the level of off-line activities are significantly related to the stimulation of CoPs. At the same time, the performance of CoPs which have their sponsors was found significantly higher than that of CoPs which have no sponsor. These results indicate that firms need to pay special attention to organizational sponsorship when introducing CoPs within their organizations.