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The Vegetational History of korea During the Holocene Period (홀로세 중 한국의 식생사)

  • 강우석
    • The Korean Journal of Quaternary Research
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    • v.8 no.1
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    • pp.9-22
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    • 1994
  • The vegetational and environmental history of Korea during the Holocene period has reconstructed by the use of folral, palaeoclimatogical, archaeological data and written records. From 10,000 to 6,700 yeat B.P. in mid-eastern Korea, deciduous broadieaved trees gradually increased trees, notably at c.8,000 years B.P. From 6,700 to 4,500 years B.P., the vegetation remained dominated by Quercus and pinus(Diploxylon). Vegetational informations suggest the postglacial hypsithermal from c.8,000 to 4,500 years b.p. After 4,500 until 1,400 years B.P., the admixture of cryophilous trees in midland and thermophilous trees in south seems to imply the latitudinal divisions of vegetation and climate. The presence of cultivated rice pollen as well as non-arboreal pollen and spores indicates an increased rate of deforestation. From 1,400 years B.P., there was a sharp decrease in the representation of temperate trees, but the presence of the cryophilous genera Abies and pinus (Haploxylon) is noticea-ble and might be related to the occurrence of Little Ice Age. Fossil pollen diagram from western Korea and eastern Korea since 6,250 and 10,000 yeats B.P., respectively have enabled to compare vegetational dis-tribution patterns and changes in the Holocene period. In western Korea, Alnus- dominated vegetation continued from 6,250 to 1,500 years B.P., but pinus took over Alnus from 1,500 years B.P. In eastern Korea, however, Quercus and pinus dominated from 10,000 to 2,000 years B.P., but pinus be-came predominant from 2,000 years B.P. On a time- spatial basis, different vegetational distribution pattern can be recognised between western and east-ern Korea. The use of seven historical records which is unique to Korea also enabled to reconstruct the distributional pattern and temporal change of vegetation from 1425 to 1928.

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Fabrication of Mono-Dispersed Ultrafine BaTiO$_3$ Powder Using Microwave (마이크로파를 이용한 초미세 균일 분산 BaTiO$_3$ 분말 제조)

  • 김현상;최광진;이상균;김영대;심상준;우경자;김경림;조영상
    • Journal of the Korean Ceramic Society
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    • v.36 no.4
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    • pp.343-353
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    • 1999
  • Microwave(2.45 GHz) was used as energy source in hydrothermal reaction to fabricate ultrafine BaTiO3 powder. Using microwave of 700 W, crytal BaTiO3 began to fom after 5 min in microwave-autoclave sys-tem. The crystallinity was not noticeably increased with increasing longer reaction time than 10 min. On the other hand in microwave-reflux system crytal BaTiO3 began to form after 15min and the crystallinity was not noticeably increased with increasing longer reaction time than 1hr,. In either case particle size dis-tribution was considerably uniform due to the effect of homogeneous heating by microwave. In addition mi-crowave heating gave an extremely small degree of particle agglomeration compared to electric heating. Av-erage sizes of as-synthesized powders were 30-60nm. Ba/Ti ratio in sol played an important role in det-ermining the particle size. It seems that excess barium forms different phases such as Ba(OH)2 which makes thin layer on the surface of BaTiO3 powder. This thin layer would inhibit the agglomeration of Ba-TiO3 powders and keep the small grain size. In microwave-autoclave system tetragonal-BaTiO3 was formed directly by the reaction of only 15 min. In the case of microwave-reflux system tetragonal-BaTiO3 was formed by driyng over 25$0^{\circ}C$.

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A Study on the Changes of Outdoor Space System in Korean Rural Villages - A Comparative Study of Changes in Residential Environment Accompanied by the Rural Village Improvement Projects - (한국 농촌마을의 옥외공간체계 변화에 관한 연구 - 취락구조 개선사업에 따른 주거환경의 변화 비교를 중심으로-)

  • 엄붕훈
    • Journal of the Korean Institute of Landscape Architecture
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    • v.18 no.2
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    • pp.31-44
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    • 1990
  • This study was carried out to investigate the changes of rural residential environmemts accompanied by the rural village improvement projects. The results of this study can be a guidoline for further betterment works of rural village envirnments. This sutdy is composed of the survey of two major parts, one Is the interview of the residents and the survey of existing conditions of residential environments, and the other is a questionnaire survey of the mental image, preference and satisfaction for each village residential environments. Based on preliminary investigation, five rural villages, located In Kyungsamgun., Kyungbuk province, were selected as sutdy sites. The major results are summarized as follows; 1. In socio-cultural enveronments, the ratio of compound and non - agricultural household are increased with the modernization of rural villages. On the ocher hand, the numbers of neighbor's association are considerably decreased. This means the traditional community of korean rural villages are diminishing. 2. In physical environments, the ratio of improved western type gouses are increased In modprnized villages. And the modernization is most remarkable in the palls of fences and gardens. 3. By the result of the analysis of residfnt's environmental image and preference, the image scores of urban, formal, mdoern, etc. are showed to be high. And the preference is also high in modernized villages. But in general, the Preference for the village environment is comparatively low in all villages. This means the improvememt work should be continuous and systematic. 4. By the result of stepwise regression analysis, the variables, affecting the preference of village environment. are regularity, familiarity, amount of greenery, beauty of surrounding scenery, convenience, cleanness, etc. The R2s of the perference models were 0.4486 ∼0.9395, Which are considered to be high. 5. In the satisfaction for each residences, the toilets are mostly dis - satisfying. With the modernization of vilelages, the needs for environmental quality by residents are increased. 6. In the satisfaction for village enveironments, the satisfaction level is most low in service facilities, such as public bath, barbershop. And the satisfaction for the scenic beauty, the amenity of surrondings, and the com munity of the traditional villages, are commparatively high in conventional villges. 7. The imporvement works, based on the characteristics of each rural villages, are recommended. And the tradition of Jung - ja tree spaces and harmony with surrounding landscape of traditional villages, must be conserved with good regards.

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The Effects of Expectancy-Disconfirmation of Attraction Affecting Visitor's Satisfaction in Natural Recreation Forests - Focused on Recreational Resources and Facilities - (자연휴양림(自然休養林) 매력물(魅力物)의 기대불일치(期待不一致)가 이용만족도(利用滿足度)에 미치는 영향(影響) - 자연휴양림의 휴양자원과 시설을 중심으로 -)

  • Lee, Ju-Hee;Bae, Min-Ki
    • Journal of Korean Society of Forest Science
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    • v.95 no.4
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    • pp.459-467
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    • 2006
  • The purpose of this study was to identify the effects of expectancy-disconfirmation (ED) of attraction affecting visitor's satisfaction in natural recreation forest (NRF). After reviewing the literature about recreational resources (RRs), facilities, ED, and visitor's satisfaction in NRF, this study analogized 11 attractions of NRF and constructed the conceptual framework. This study had obtained data through a questionnaire, which surveyed 415 visitors at 3 NRFs in 204 summer season. This study found that 1) The expectancy-performance of visitor's interesting resources is the highest among RRs, 2) There was mean difference between expectancy and performance of attraction at one percent significant level, 3) Safety facility had the highest ED value and plant resources had the lowest ED value, 4) The higher ED value of attractions, the lower value of visitor's satisfaction, 5) in multivariate analysis, such variables as physical resource, social culture resource, lodging facility, foundation facility, safety facility, sanitary facility, and education facility have been turned out be statistically significant at one percent level, 6) The relative contribution of the ED of foundation facility, lodging facility, and education facility on visitor's satisfaction have ben determined to have respectively 2.50, 1.48, and 1.88 times more important than that of physical resources.

Significance of Dissimilatory Fe(III) Reduction in Organic Matter Oxidation and Bioremediation of Environmental Contaminants in Anoxic Marine Environments (혐기성 해양환경에서 철 환원세균에 의한 유기물 분해 및 생물정화)

  • Hyun Junc-Ho
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.10 no.3
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    • pp.145-153
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    • 2005
  • I reviewed an ecological and environmental significance of microbial carbon respiration coupled to dis-similatory reduction of fe(III) to Fe(II) which is one of the major processes controlling mineralization of organic matter and behavior of metals and nutrients in various anaerobic environments. Relative significance of Fe(III) reduction in the mineralization of organic matter in diverse marine environments appeared to be extremely variable, ranging from negligible up to $100\%$. Cenerally, Fe(III) reduction dominated anaerobic car-bon mineralization when concentrations of reactive Fe(III) were higher, indicating that availability of reactive Fe(III) was a major factor determining the relative significance of Fe(III) reduction in anaerobic carbon mineralization. In anaerobic coastal sediments where $O_2$ supply is limited, tidal flushing, bioturbation and vegetation were most likely responsible for regulating the availability of Fe(III) for Fe(III) reducing bacteria (FeRB). Capabilities of FeRB in mineralization of organic matter and conversion of metals implied that FeRB may function as a useful eco-technological tool for the bioremediation of anoxic coastal environments contaminated by toxic organic and metal pollutants.

The Age and Sex-specific Quality of Life by Chronic Disease Using the EQ-5D Index : Based on the 2017-2019 Korea National Health and Nutrition Examination Survey (EQ-5D 지수를 활용한 만성질환별 삶의 질의 성별 및 연령에 따른 변화: 2017~2019년 국민건강영양조사 자료를 이용하여)

  • Gyung-Jun Chae;Se-Ho Park;Seung-A Song;Jun-Kyu Lee;Jong-min Hong;Jae Seok Song;Nam Jun Kim
    • Journal of agricultural medicine and community health
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    • v.48 no.2
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    • pp.81-90
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    • 2023
  • Objectives: This study analyzed the decline in quality of life according to age in the chronic disease patient group, quantified it as a quantitative index, and compared it by sex and chronic disease. Methods: In the 2017-2019 Korea National Health and Nutrition Examination Survey database, 11,473 adults aged 19 years or older, excluding cancer patients, were analyzed for age-specific changes in the EQ-5D Index by chronic disease. The decline in quality of life according to age in patients with chronic diseases was analyzed by linear regression analysis while controlling for general characteristics. Then, linear regression analysis was performed according to sex. Results: In the case of the control group, the quality of life decreased by 0.0004 for every 1-year increase in age(P<0.001). By chronic disease, asthma(β=0.0019, P<0.001), arthritis(β=0.0017, P=0.002), thyroid dis- ease(β=0.0016, P=0.015), dyslipidemia(β=0.0011, P=0.020), and hypertension(β=0.0009, P=0.027) mostly showed a greater decrease in quality of life than the control group. In addition, when divided into two groups by sex, hypertension(β=0.0012, P=0.029), thyroid disease(β=0.0041, P=0.038), and arthritis(β=0.0022, P<0.001) showed a significant decrease in quality of life only in male. Diabetes(β=0.0056, P=0.038), dyslipi- demia(β=0.0022, P=0.001) significantly decreased quality of life only in female. Conclusions: Chronic disease had a negative impact on patients perception of quality of life, and the more severe the pain and activity limitation due to the chronic disease, the more severe it was. It also showed different patterns according to sex. Therefore, it is necessary to allocate more medical resources and provide policy support to prevent chronic diseases, which are serious social problems.

Changes in Ultrastructure of Tissues, Characteristics of Protein and Soybean Curd Yield with Increased Soaking Time during Soybean Curd Processing (대두(大豆)의 수침시간(水浸時間)에 따른 조직(組織)의 미세구조(微細構造), 단백질(蛋白質) 특성(特性) 및 두부수율(豆腐收率)의 변화(變化))

  • Park, Yong-Gone;Park, Boo-Duck;Choi, Kwang-Soo
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.14 no.4
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    • pp.381-386
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    • 1985
  • This experiment was conducted to investigate changes of soybean curd yield according to the extension of soaking time during manufacturing of soybean curd. To investigate those changes systematically, transmission electron microscopy and disc-gel electrophoresis were used. The soybean curd yield was increased from 45.0% to 50.5% and 55.4% respectively as soaking time is extended from 5 hours to 10 and 24 hours. The solid extraction and soybean milk coagulation were also increased according to the extension of soaking time. From disc-gel electrophoresis patterns of soybean milk protein and soybean curd protein, numbers of band were increased and major band thickened by expending the soaking time. Most of high molecular bands of soybean milk protein were transfered to soybean curd. Crude 7S proteins of soybean milk and soybean curd in dis-gel electrophoresis were appeared to be 4 and 5 bands respectively, and crude 11S proteins of soybean milk and soybean curd were appeared to be 9 and 8 bands respectively. Of soybean milk bands, most of 11S component transfered to soybean curd. Transmission electron photomicrographs revealed that the dimension of each protein body became larger and the numbers of spherosome around the protein bodies in unit area fewer by extending the soaking time of soybean.

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Does Geography Matter in Technological Partner Selection? (지식확산과 집적경제를 고려한 기업의 기술협력파트너 위치선정 행태)

  • Jo, Yu-Ri
    • Journal of Technology Innovation
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    • v.19 no.2
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    • pp.153-184
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    • 2011
  • This paper investigates what kind of technological partner firms want to cooperate with in terms of partner location. Two geographical factors are considered. One is geographical proximity, given the tradeoff between the effectiveness of knowledge spillovers in proximity and diverse knowledge absorption from geographically distant partners. The other is how many other firms are co-located with potential partners because it is known that clustering regions can create more technological outputs. Analysis on 2008 Korea Innovation Survey data finds that partner proximity is the single most important factor in choosing a cooperation partner. While firms that are located in a region crowded with related industries prefer proximate partners, others that are surrounded by unrelated industries are more likely to cooperate with distant partners. The findings suggest that geographical proximity matters in partner selection because it not only stimulates knowledge spillovers but also reduces costs involving R&D cooperation such as monitoring costs and information costs. Moreover, firms take into consideration both the benefits and risks of clustering regions. If there are so many unrelated firms that they create agglomeration diseconomies such as congestion costs and unintentional knowledge leakages, firms are more likely to try to find their cooperation partners in other regions.

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A Study on the Life History of Post-prostitute Women: Episodes of Endless Escapes from the Public (탈성매매 여성들의 생애사 연구 : 그 끝없는 탈주에 대하여)

  • Kim, Young-Sook;Lee, Keun-Moo
    • Korean Journal of Social Welfare
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    • v.60 no.3
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    • pp.5-30
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    • 2008
  • The purpose of this study is to propose a practical intervention program for the women who got out of prostitution. For the research we selected the seven women who had ever engaged in prostitution by snowball sampling. Qualitative data were accumulated by in-depth interview and private documents collection. We analyzed the raw data following the Mandelbaum's conceptual frame ; dimension of life, turning point and adaptation. In analysis of the dimension of life, home, religion and occupation were represented as main thems. Home was interpreted as the reconstruction of existential field that assumes their fault and others. Religion was interpreted as the phenomenological field that develops their potentiality and peculiarity. Occupation was interpreted as the restraining means aganist returning to prostitution. In analysis of the turning point, we found a common theme : dis empowering the discourse power by body-politics. In analysis of the adaptation, we found three propositions as fellows: 1) "Living with stigma internalized by themselves" 2) "Living as anonymous being and absconding" 3) Expunging the past disgrace through shifting of social status. Based on the above results we proposed practical approaches for them.

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Multi-Interface Multi-Channel R-HWMP Routing Protocol for End-to-End Bandwidth Reservation in IEEE 802.11s WMNs (IEEE 802.11s 무선 메쉬 네트워크에서 종단간 대역폭 예약을 위한 멀티 인터페이스 멀티 채널 R-HWMP 라우팅 프로토콜)

  • Jung, Whoi Jin;Kim, Bong Gyu;Lee, Jae Yong;Kim, Byung Chul
    • Journal of the Institute of Electronics and Information Engineers
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    • v.51 no.7
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    • pp.37-48
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    • 2014
  • Wireless mesh networks have emerged as a key technology in environment that needs wireless multi-hop communication without infrastructure and IEEE 802.11s mesh network standard have currently been established. One of big differences between this standard and the legacy IEEE 802.11 is that MCCA MAC is included to support QoS. MCCA supports bandwidth reservations between neighbors, so it can satisfy the QoS of bandwidth guarantee. However, MCCA has dis-advantages as follow; 1) it can not guarantee end-to-end bandwidth, 2) in multi-interface multi-channel wireless environments, the IEEE 802.11s does not provide a bandwidth reservation protocol and a wireless channel assignment etc. In this paper, we have proposed MIMC R-HWMP, which expands R-HWMP that was proposed in our previous work[3], to support multi-interface multi-channel. By simulation, we showed end-to-end bandwidth guarantee and the increase in the available bandwidth in multi-interface multi-channel wireless mesh networks.