• Title/Summary/Keyword: Community stability

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Function of Habitat Heterogeneity for the Biodiversity and Demography of Population in Small Mammal Community (소척추동물군집에서 개체군 변동과 생물다양성 유지를 위한 서식지 이질성의 기능)

  • Lee, Sang Don
    • The Korean Journal of Ecology
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    • v.18 no.4
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    • pp.512-523
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    • 1995
  • The central theme of Habital heterogeneity is to provide animals with habital complexity or structural diversity and to allow resource partitioning among individuals. In turn, the leads to population stability because prey can escape more easily with more hiding places causing less population fluctuation. Species diversity is characterized due to more potential niches both horizontally and verticall. Empirically, in homogeneous habitats population was less abundant, reproduction and survival were lower, spacing behavior, competition and dispersal were higher than in heterogeneous habitats. The results imply that diversity and conservation of species can be maintained through providing heterogeneous habitats.

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Relationships between Small Mammal Community and Coarse Woody Debris in Forest Ecosystem (산림 생태계에서 소척추동물 군집과 잔목의 관계)

  • Lee, Sang-Don
    • The Korean Journal of Ecology
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    • v.20 no.4
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    • pp.251-258
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    • 1997
  • Few attempts have been made to discover the ecological function of coarse woody debris (CWD) despite its importance to small mammal population. Twenty-five pitfall traps and a hundred live traps were placed in three sites with high amounts of CWD and three sites with low amounts of CWD. Eleven species were caught, and Peromyscus maniculatus was the most abundant (45.6%, n=605). Among 11 speices, abundance of Tamias townsendii and Clethronomys gapperi were higher in sites with high amounts of CWD than in sites with low amounts of CWD. Home range size was larger in breeding season than in non-breeding season indicating mating search. Resident time of Peromyscus maniculatus was longer in sites with high amounts of CWD implying better stability in population. The increasing amount of coarse woody debris (CWD) enhanced the habitat use by small mammals, and animals in high amounts of CWD were more abundant and stable in population fluctuation. This study, therefore, concludes that CWD is a critical habitat element for small mammals in forest ecosystem.

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Explorized Policy Iteration For Continuous-Time Linear Systems (연속시간 선형시스템에 대한 탐색화된 정책반복법)

  • Lee, Jae-Young;Chun, Tae-Yoon;Choi, Yoon-Ho;Park, Jin-Bae
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.3
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    • pp.451-458
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    • 2012
  • This paper addresses the problem that policy iteration (PI) for continuous-time (CT) systems requires explorations of the state space which is known as persistency of excitation in adaptive control community, and as a result, proposes a PI scheme explorized by an additional probing signal to solve the addressed problem. The proposed PI method efficiently finds in online fashion the related CT linear quadratic (LQ) optimal control without knowing the system matrix A, and guarantees the stability and convergence to the LQ optimal control, which is proven in this paper in the presence of the probing signal. A design method for the probing signal is also presented to balance the exploration of the state space and the control performance. Finally, several simulation results are provided to verify the effectiveness of the proposed explorized PI method.

Residential Satisfaction of Households living in Super-High Rise Apartment in Ulsan (울산시 초고층 아파트 거주자의 주거만족도)

  • 김선중;김수정
    • Journal of the Korean Home Economics Association
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    • v.37 no.3
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    • pp.101-110
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    • 1999
  • The purpose of this study was to invesitigate the residential satisfaction of households living in super-high rise apartment. The questionnarles were collected from 244 residents living in super-high rise apartment above 20 stories located in Ulsan. Used statistical techniques were frequency, one-way ANOVA. The major findings were as follows: 1) Although the respondents were dissatisfied with super-high rise apartments, they chose present dwelling due to public transportation, easy access to work, and other community facilities. 2) Households who have more educated husband and wife and younger child were less satisfied with current dwelling. 3) The attrative features of super-high rise apartment were interior facilities, exterior environment, and social relations, While the negative features were interior environment, safety, and psychological stability.

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Investigation of Users' Goals in Social Network Sites (소셜네트워크사이트 사용자의 가치체계 연구)

  • Jung, Yoonhyuk
    • The Journal of Information Systems
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    • v.23 no.1
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    • pp.93-109
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    • 2014
  • This study aims to develop a rich understanding of user goals in user-empowering information technologies which have been dominating part in the information systems environment. A particular focus is on users' goals in a social network site (SNS) which is a typical example of user-empowering technologies. Users conduct various activities in order to achieve diverse goals in SNS. Thus, investigating what goals users pursue in SNS will give insights into understanding the users. We employed the laddering interview technique and means-end chain approach. Interviews of 50 Facebook users were analyzed to produce a hierarchical goal map showing users' goal structure. The map contains 18 goals, including self-reflection, psychological stability, belongingness, improving productivity, and amusement as ultimate goals in SNS. In the map, there are varied routes from activities to ultimate goals in SNS; that is, a complex assembly consisting of activities and goals. The findings call the information systems research community to have more interests in diverse goals and values users seek with technologies.

Localization Process of Agricultural Extension Personnel and the Tasks for the Future (농촌지도직 공무원의 지방직 전환 과정과 앞으로의 과제)

  • Kim, Sung-Soo
    • Journal of Agricultural Extension & Community Development
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    • v.3 no.2
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    • pp.167-176
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    • 1996
  • Localization process of agricultural extension personnel in Korea were in progress with insufficient debates for effective personnel management. Although the members of the Korean Agricultural Extension Society were strongly opposed to the plan to decentralize agricultural extension personnel from central to local government status, the administrative action took place to localize as of January 1997. The Korean Agricultural Extension Society filed the petition against to the plan pinpointing lowered morale of extension personnel, the financial burden of local governments, jeopardizing stability, undermining efficiency, and people`s attitude towards central and local government. The dangers of decentralization of agricultural extension services may cause serious problems in varied areas. More extensive debates would be needed in deciding the future directions of agricultural extension services analyzing the basic characteristics of agricultural extension, linkages of research and extension, financial burden of local government, specialization of extension personnel, and unnecessary duplication of investment among local governments.

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중국공산당 이데올로기 전략의 효용성 연구 - 중국의 정치사상교육을 중심으로

  • Lee, Dong-Gyu
    • 중국학논총
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    • no.68
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    • pp.141-161
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    • 2020
  • This paper aims to analyze China's political education, which plays a role of vehicle in the Chinese Communist Party (CCP) promoting its ideological strategy, in order to figure out the utility of the CCP's ideological strategy. After Reform and Opening Up, the CCP rebuilt and reinforced political education in China according to its ideological strategy. Especially after the Tiananmen incident in 1989, the CCP made nationalism and patriotism as the core part of political education, and expanded its curriculum. Such reinforcement of political education has a advantage in maintaining the CCP's governance by creating a nationalist consensus against the western ideas. Although it can be helpful for the stability of domestic politics, it also has negative possibilities which isolate China in the global community and obstruct China's development.

A Cross-sectional Survey on Drug Abuse among High School Students in Taegu City (대구시내 고등학생의 약물남용에 관한 연구)

  • Lee, Hyun-Sook;Kim, Chung-Nam;Oh, Yun-Jung
    • Research in Community and Public Health Nursing
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    • v.8 no.2
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    • pp.347-367
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    • 1997
  • The purpose of this study was to investigate drug abuse and to find related factors among high school students. The subjects for this study were 973 students from 10 high schools in Taegu city. The data were collected from September 30, 1996 to October 30, 1996. The questionnaire developed by Kim Soyoaja (1991) surveyed adolescent drug use and questions on smoking and drinking were readjusted and added by the researcher based on review. The data was analyzed using frequency, percentage, $X^2-test$, t -test, Pearson Correlation Coefficient with the SPSS /PC+. The results of this study were summarized as follows: 1. The proportion of students who drank alcohol 1-2 times or more per year was 52.4% and smoked Cigarette 1 -2 times or more per year was 20.8%. The 7 different drugs(Analgetics 5.7%. sleeping pills and sedatives 4.2%, antihistamines 1.1%. stimulants 7.7%, hallucinogens 0.8%, inhalants 3.3%, and narcotics 0.6%) were also evaluated. 2. There was a significant relationship between drinking and type of school($X^2$=62.97, p<.0l), grades($X^2$=33.86, P<.001), school life($X^2$= 19.04, p<.001), and delinquent friends($X^2$= 64.72, P<.001). 3. There was a significant relationship between smoking and type of school($X^2$=153.65, p<.001), grades ($X^2$=67.53, p<.001), their respect for teachers ($X^2$=33.80, p<.001) school life($X^2$ =50.87, p<.001), and delinquent friends($X^2$ =85.28, p<.001). 4. There was a significant relationship between the 7 different kinds of drug abuse and type of school ($X^2$=14.65, p<.01), grades($X^2$=12.89, p<.01), their respect for teachers ($X^2$=8.46, p<.05), and delinquent friends($X^2$=22.42, p<.001). 5. There was a significant relationship between a parent's habitual drug abuse and the 7 different kinds of drug abuse($X^2$=7.78, p<.01), as well as a parent's attitude toward drugs and the 7 different kinds of drug abuse($X^2$=6.33, p<.05). 6. There was a significant difference between drinking(t=-12.53, p<.001), smoking(t=-15.98, p<.001), the 7 different kinds of drug abuse(t=-5.77, p<.001), and the respondant's delinquent experience. 7. There was a correlation between drinking and smoking(r=.4166, p<.001), drinking and the 7 different kinds of drug abuse(r=.2200, p<.001), smoking and the 7 different kinds of drug abuse(r=.1428, p<.05). There was a correlation between drinking and smoking(r=.5977, p<.001), drinking and the 7 different kinds of drug abuse(r=.2849, p<. 001), smoking and the 7 different kinds of drug abuse(r=.1711, p<.05) among male students. There was a correlation between drinking and smoking(r=.4219, p<.001), drinking and the 7 different kinds of drug abuse(r=.2611, p<.001), smoking and the 7 different kinds of drug abuse(r=.1764, p<.001) among female students. 8. There was a correlation between drinking and family stability(r=.0709, p<.05) drinkry and parent -child relationships (r=.1321, p<.01), drinking and mother's rearing attitude(r=.0704, P<.05), smoking and parent -child relationships(r=.0813, P<.05). There was a correlation between drinking and family stability(r=.14S7, p<.01), drinkng and parent-child relationships(r=.2147, p<.001), smoking and family stability(r=.1544, p<.01), smoking and parent. -child relationships (r=. 2018, P<.01) among male students. There was a correlation between drinking and family stability(r=.1l21, p<.05), drinking and mother's rearing attitude (r=.0988, P<.05), smoking and parent -child relationships (r=. 0940, P<.05) among female students. 9. There was a significant difference between the 7 different kinds of drug abuse and family stability (t=2.23, p<.05), parent-child relationships (t=4. 34, p<.001), satisfaction with family (t=4.02, p<.001), father's rearing attitude(t=3.04, p<.01), mother's rearing attitude(t=2.87, p<.01). The distribution channel of drugs including alcohol beverages and cigarettes should be evaluated and restructured to discourage student's temptation and to limit accessibility. The step by step preventive teaching on alcohol drinking and cigarette smoking is needed from middle school to help prevent further drug abuse.

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Molecular Analysis of Microbial Community in Soils Cultivating Bt Chinese Cabbage (분자생물학적 분석을 통한 Bt 배추의 토양미생물상 영향 비교평가)

  • Sohn, Soo-In;Oh, Young-Ju;Oh, Sung-Dug;Kim, Min-Kyung;Ryu, Tae-Hoon;Lee, Ki-Jong;Suh, Seok-Choel;Baek, Hyeong-Jin;Park, Jong-Sug
    • Korean Journal of Environmental Agriculture
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    • v.29 no.3
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    • pp.293-299
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    • 2010
  • The aim of this study was to investigate the possible impact of Bt Chinese cabbage on the soil microbial community. Microbial communities were isolated from the rhizosphere of one Bt Chinese cabbage variety and four varieties of conventional ones and were subjected to be analyzed using both culture-dependent and molecular methods. The total counts of bacteria, fungi, and actinomycetes in the rhizosphere of transgenic and conventional Chinese cabbages were observed to have an insignificant difference. Denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified 16S rRNA genes revealed that the bacterial community structures were very similar to each other and this genetic stability of microbial communities was maintained throughout the culture periods. Analysis of dominant isolates in the rhizosphere of transgenic and conventional Chinese cabbages showed that the dominant isolates from the soil of transgenic Chinese cabbage belonged to the Bacilli and Alphaproteobacteria, while the dominant isolates from the soil of conventional cabbage belonged to the Holophagae and Planctomycetacia, respectively. These results indicate that the Bt transgenic cabbage has no significant impact on the soil microbial communities.

A Phenomenological Study on Performance of Cultural Welfare Services (문화복지서비스 성과에 관한 현상학적 연구 - 서비스 이용자의 인식을 중심으로 -)

  • Yu, Young Ju
    • Korean Journal of Social Welfare Studies
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    • v.44 no.3
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    • pp.271-300
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    • 2013
  • The objective of this study is to discover how the performance of service is perceived by those who receive the services. For the purpose of this study, perception on service performance is defined as "the perception of the changes in daily life as a result or in the course of using Cultural Welfare Services, i.e., the users' own perception of the tangible changes made through the community experience, the perception of others arising from interaction within the community, and the perception of future social relations or vision of the future." The study was conducted by using the qualitative research method of phenomenological approach aimed at understanding the essential aspects of interpersonal phenomena as they occur in a sociocultural context. The outcomes of the study that users' perception on performance of Cultural Welfare Services is principally "a process of enabling users who have hitherto led a life devoid of meaning and values to explore the opportunities of changing the course of life by awakening their cultural sensitivity." With regard to the essence of performance, which is a higher category, the analyses have led to the following findings: "perception of 'me' within the community", "emotional stability acquired in the course of task performance", "perception of a new 'me' through community activities", "perception of 'others' face to face with me", and "exploration of opportunities for a new life".