• Title/Summary/Keyword: Horizon

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Experimental Assessment of Forest Soil Sensitivity to Acidification(II) - Application of Extractable Sulfate and Sulfate Adsorption Capacity - (산림토양(山林土壤)의 산성화(酸性化) 민감도(敏感度)에 대(對)한 실험적(實驗的) 평가(評價)(II) - 추출성(抽出性) 황산(黃酸)이온(SO42-) 함량(含量)과 황산(黃酸)이온 흡착능(吸着能)의 활용(活用) -)

  • Lee, Sung Woo;Kim, Young Kul;Lee, Choong Hwa;Byun, Jae Kyoung
    • Journal of Korean Society of Forest Science
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    • v.90 no.4
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    • pp.431-436
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    • 2001
  • The extractable sulfate content and sulfate adsorption capacity in soils of four Pinus densiflora stands were measured to assess the soil acidification sensitivity to acid deposition. The soluble sulfate content in organic horizon which reflects the previous deposition of sulfur oxides was much higher for Namsan and Ulsan than Kanghwa and Hongcheon. In mineral soils, however, the extractable sulfate content was the greatest for Ulsan followed by Kanghwa, Namsan and Hongcheon due to the interactive effect of previous deposition and soil adsorption of sulfate. Adsorption rates of specifically adsorbed sulfate(proportion of insoluble sulfate to total extractable sulfate) for Namsan, Kanghwa and Ulsan affected by acid deposition were 16.6%, 56.8% and 37.4%, respectively, so that the soil in Namsan had the highest acidification sensitivity to acid deposition. For sulfate adsorption isotherm($RE=mX_i-b$), the significantly positive correlations between added sulfate($X_i$) and adsorbed sulfate(RE) were found only in mineral soil(p<0.05) over all regions. The regression coefficient(m) that means soil sulfate adsorption capacity by 0-30cm depth was 0.16, 0.24, 0.25 and 0.32 in $mmol_c\;kg^{-1}$ for Namsan, Kanghwa, Ulsan and Hongcheon, respectively, indicating that soil acidification sensitivity is the highest for Namsan. The added sulfate($X_i$) that could make the adsorbed sulfate(RE) null was 3.81, 2.17, 4.96 and 0.65 in $mmol_c\;kg^{-1}$ for Namsan, Kanghwa, Ulsan and Hongcheon, respectively and the values of former three regions considerably exceeded the realistic sulfate deposition.

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The Yellow Sea Ecoregion Conservation Project : the Present Situation and its Implications (황해생태지역 보전사업 추진현황 및 시사점)

  • Kim, Gwang Tae;Choi, Young Rae;Jang, Ji Young;Kim, Woong-Seo
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.15 no.4
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    • pp.337-348
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    • 2012
  • The Yellow Sea Ecoregion Conservation Project is a joint international project which is carried out under the purposes of conserving the habitats in the Yellow Sea Ecoregion and biodiversity from various threats that damage ecosystems, informing the importance and value of the Yellow Sea Ecoregion, and promoting the understanding and interests of Korea, China and Japan. Subsequent to the Yellow Sea Ecoregion Planning Programme which had been performed during the period from 2002 to 2006, the Yellow Sea Ecoregion Support Project has been performed over 7 years in total from 2007 to 2014. Panasonic is sponsoring the financing of the project, and the organizations in charge of the project by country are Korea Institute of Ocean Science & Technology for Korea and World Wide Fund for Nature branches for China and Japan. While the Yellow Sea Ecoregion Planning Programme was focused on the biological assessment and the selection of potential priority area by scientific review, the Yellow Sea Ecoregion Support Project is oriented toward practical activities targeting more diversified stakeholder. Especially, this project plans to support direct conservation activities in the region and participation and cooperation from local residents. The project plan is comprised of 3 phases. During the first period from 2008 to 2009, small grant projects were operated targeting 16 institutions of Korea and China, and for the second period from 2010 to 2012, one place each was selected as demonstration site for habitat conservation in Korea and China respectively and supported for three years to introduce the conservation method based on international standards such as the management of marine protected areas, ecosystem-based management and community-based management and simultaneously to develop habitat conservation activities suitable for national and regional characteristics. During the period from 2013 to 2014 which is the last phase, the project plans to distribute the performance of small grant projects and demonstration site activities through a series of forums among stakeholder. Through the activities described above, the recognition of general public on the conservation of the Yellow Sea Ecoregion was changed positively, and community-based management began to be reflected in the policies for the marine protected areas of central and local government.

A Study on characteristics of planosols in korea -Part I Yeongog series (우리나라에 분포(分布)된 반층토(盤層土)의 특성(特性)에 관(關)한 연구(硏究) -제(第)1보(報) 연용통(延谷統)에 관(關)하여)

  • Um, Ki Tae;Cho, Seong Jin
    • Korean Journal of Soil Science and Fertilizer
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    • v.8 no.2
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    • pp.45-51
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    • 1975
  • The morphological, physical, chemical, and mineralogical characteristics of planosols in Korea were studied in an effort to establish the suitabilition of the planosols for agricultural development. The Yeongog series which are planosols were established in Korea. Results from the Yeongog series are briefly as follows : 1. Morphologically, the surface soils are brown to dark brown friable loam and subsoils are of varied colors but mainly are dark brown, black and pale brown mottles. The texture of these horizons are silty clay loam with moderate to strong platy structure and clay cutans are on the ped faces. The consistences of these horizons are extremely compact and hard when moist and sticky, plastic when wet. The substrata show varied soil colors and loam to clay loam. 2. Physically, the clay content of the Yeongog soils is highest in the subsoils and gradually decreases below the subsoils. Water holding capacity and bulk desity is higher than in other mineral soils. 3. Chemically, the organic matter content is low and soil reaction ranges from very strongly to strongly acid. The cation exchange capacity is medium and base saturation a high. Active iron, easily reducible manganese and available silicate are high compared with normal soils. 4. In chemical composition of clay fraction of the Yeongog series, sesquioxide ratio, $Fe_2O_3$, $K_2O$ and MgO are high. The cation exchange capacity of the clay fraction is also very high. 5. The clay minerals in Yeongog series are mainly kaoline, vermiculite with Al interlayers and illite. The quarts, primary minerals are in the Yeongog soils. 6. These soils are formed in a warm, humid climate under native grasses on the terraces and rolling or hilly footslopes. In soil classification, the Yeongog soils are classified planosols with claypan. According to 7th approximation system in U.S.A., the Yeongog series are classified as Fragiudalfs because they have an argillic horizon, a hard pan and a high base saturation which is more than 35 percent and classified as Eutric Planosols by FAO/UNESCO classification system.

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Economic Value of the Sirolimus Eluting Stent($CYPHER^{TM}$) in Treating Acute Coronary Heart Disease (관상동맥질환 치료를 위한 시롤리무스 방출 스텐트 ($CYPHER^{TM}$)의 경제성 분석)

  • Lee, Hoo-Yeon;Park, Eun-Cheol;Park, Ki-Dong;Park, Ji-Eun;Kim, Young;Lee, Sang-Soo;Kang, Hye-Young
    • Journal of Preventive Medicine and Public Health
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    • v.36 no.4
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    • pp.339-348
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    • 2003
  • Objective : To quantify the economic value of the Sirolimus fluting Stent ($CYPHER^{TM}$) in treating acute coronary heart disease (CMD), and to assist in determining an adequate level of reimbursement for $CYPHER^{TM}$ in Korea. Methods : A decision-analytical model, developed by the Belgium Health Economics Disease Management group, was used to investigate the incremental cost-effectiveness of $CYPHER^{TM}$ versus conventional stenting. The time horizon was five years. The probabilities for clinical events at each node of the decision model were obtained from the results of large, randomized, controlled clinical trials. The initial care and follow-up direct medical costs were analyzed. The initial costs consisted of those for the initial procedure and hospitalization, The follow-vp costs included those for routine follow-up treatments, adverse reactions, revascularization and death. Defending on the perspective of the analysis, the costs were defined as insurance covered or total medical costs (=sum of insurance covered and uncovered medical costs). The cost data were obtained from the administrative data of 449 patients that received conventional stenting from five participating Korean hospitals during June 2002. Sensitivity analyses were peformed for discount rates of 3, 5 and 7%. Since the major clinical advantage of $CYPHER^{TM}$ over conventional stenting was the reduction in the revascularization rates, the economic value of $CYPHER^{TM}$, in relation to the direct medical costs of revascularization, were evaluated. If the incremental cost of $CYPHER^{TM}$ per revascularization avoided, compared to conventional stenting, was no higher than that of a revascularization itself, $CYPHER^{TM}$ would be considered as being cost-effective. Therefore, the maximum acceptable level for the reimbursement price of $CYPHER^{TM}$ making the incremental cost-effectiveness ratio equal to the cost of a revascularization was identified. Results : The average weighted initial insurance covered and total medical costs of conventional stenting were about 6,275,000 and 8,058,000 Won, respectively. The average weighted sum of the initial and 5-year follow-up insurance covered and total medical costs of conventional stenting were about 13,659,000 and 17,353,000 Won, respectively. The estimated maximum level of reimbursement price of $CYPHER^{TM}$ from the perspectives of the insurer and society were $4,126,897{\sim}4,325,161$ and $4,939,939{\sim}5,078,181$ Won, respectively. Conclusion : By evaluating the economic value of $CYPHER^{TM}$, as an alternative to conventional stenting, the results of this study are expected to provide a scientific basis for determining the acceptable level of reimbursement for $CYPHER^{TM}$.

Analyzing the Characteristics of Pre-service Elementary School Teachers' Modeling and Epistemic Criteria with the Blackbox Simulation Program (블랙박스 시뮬레이션에 참여한 초등예비교사의 모형 구성의 특징과 인식적 기준)

  • Park, Jeongwoo;Lee, Sun-Kyung;Shim, Han Su;Lee, Gyeong-Geon;Shin, Myeong-Kyeong
    • Journal of The Korean Association For Science Education
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    • v.38 no.3
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    • pp.305-317
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    • 2018
  • In this study, we investigated the characteristics of participant students' modeling with the blackbox simulation program and epistemic criteria. For this research, we developed a blackbox simulation program, which is an ill-structured problem situation reflecting the scientific practice. This simulation program is applied in the activities. 23 groups, 89 second year students of an education college participated in this activity. They visualized, modeled, modified, and evaluated their thoughts on internal structure in the blackbox. All of students' activities were recorded and analyzed. As a result, the students' models in blackbox activities were categorized into four types considering their form and function. Model evaluation occurred in group model selection. Epistemic criteria such as empirical coherence, comprehensiveness, analogy, simplicity, and implementation were adapted in model evaluation. The educational implications discussed above are as follows: First, the blackbox simulation activities in which the students participated in this study have educational implications in that they provide a context in which the nature of scientific practice can be experienced explicitly and implicitly by constructing and testing models. Second, from the beginning of the activity, epistemic criteria such as empirical coherence, comprehensiveness, analogy, simplicity, and implementation were not strictly adapted and dynamically flexibly adapted according to the context. Third, the study of epistemic criteria in various contexts as well as in the context of this study will broaden the horizon of understanding the nature of scientific practice. Simulation activity, which is the context of this study, can lead to research related to computational thinking that will be more important in future society. We expect to be able to lead more discussions by furthering this study by elaborating and systematizing its context and method.

Nutrient Balance during Rice Cultivation in Sandy Soil affected by the Fertilizer Management (사질논에서 벼 재배기간 중 시비방법별 양분수지)

  • Roh, Kee-An;Ha, Ho-Sung
    • Korean Journal of Soil Science and Fertilizer
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    • v.32 no.2
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    • pp.155-163
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    • 1999
  • Nutrient balance during rice cultivation in the paddy of a local area under the environmental protection for drinking water supply was investigated. To compare nutrient balance in the paddy soil applied with different types of fertilization, 7 treatments were selected as followings : Recommended level of chemical fertilizers(R), Conventional fertilization(CF), Fresh cow manure(FCM), Cow manure compost(CMC), Straw compost+reduced chemical fertilizer(SCF), Fresh straw+recommended level of fertilizers(FSC), and no fertilization as control(C). Here, FCM, CMC and SCF were applied at the same level of total nitrogen as recommended in R. Rice yield was the highest in the recommendation(R) and fresh cow manure (FCM) treatments with $6,730kg\;ha^{-1}$(index 100), and followed by SCF (index 98), FSC (index 98), CMC(index 94), and CF(index 94). But statistically significant difference was not recognized among treatments except the control. Nitrogen infiltration loss was high in the simple chemical fertilizer treatments with $63kg\;ha^{-1}$ in CF and $58kg\;ha^{-1}$ in R during rice cultivation, respectively. Nitrogen infiltration loss was decreased below half level of chemical fertilizer treatments with cow manure treatments ($23kg\;ha^{-1}$ in FCM and $27kg\;ha^{-1}$ in CMC) and with reducing chemical fertilizer treatment by adding straw compost ($25kg\;ha^{-1}$). Phosphate was not leached during rice cultivation in paddy soil of a fluvial deposit type, in which oxidation horizon was developed broadly under around 15 cm depth of surface soil. Phosphate balance (A-B) was closed to 0 in all treatments except cow manure treatment (CMC), in which it was $+30kg\;ha^{-1}$ and show the possibility of over accumulation of phosphate by continuously replicated application of cow manure compost. Potassium balance was negative value in all but straw recycling treatment (FSC). It means that potassium was continuously supplied from soil minerals, uptaken by plants or eluted out of soil. In conclusion, by substituting inorganic fertilizer for organic fertilizer or reducing application rate of chemical fertilizer through mixing organic fertilizer, it would be possible to achieve the same rice yield as in the recommendation treatment and to decrease nutrient leaching below half level in rice paddy soil.

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Evaluation of Soil Redox Capacity using Chromium Oxidation-reduction Reactions in Volcanic Ash Soils in Jeju Island (크롬산화환원반응을 이용한 제주도 화산회토양 내 토양산화환원능 평가)

  • Chon, Chul-Min;Ahn, Joo-Sung;Kim, Kue-Young;Park, Ki-Hwa
    • Journal of the Mineralogical Society of Korea
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    • v.21 no.2
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    • pp.161-175
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    • 2008
  • The soil developed from volcanic ash in Jeju Island, Korea, were classified as typical Andisols. The soils had acidic pH, high water contents, high organic matters and clay-silty textures. The crystalline minerals of the samples were mainly composed of ferromagnesian minerals such as olivine and pyroxene, and iron oxides such as magnetite and hematite derived from basaltic materials. A large amount of gibbsite was found at the subsurface horizon as a secondary product from the migration of excessive aluminum. In addition, our study has shown that considerable amounts of poorly ordered minerals like allophane and ferrihydrite were present in Jeju soils. The contents of $SiO_2$ were lower than those of other soil orders, but $A1_2O_3$ and $Fe_2O_3$ contents were higher. These results are some of the important chemical properties of Andisols. The contents of heavy metals were in the range of $84{\sim}198$ for Zn, $56{\sim}414$ for Ni, $38{\sim}150$ for Co, $132{\sim}1164\;mg\;kg^{-1}$ for Cr, which are higher than the worldwide values in most of the soils. Some soil samples contained relatively high levels of Cr exceeding 1000 mg/kg. Mean reduction capacity of the Jeju soils was $6.53\;mg\;L^{-1}$ reduced Cr(VI), 5.1 times higher than that of the non-volcanic ash soils from inland of Korea. The soil reduction capacity of the inland soils had a good correlation with total carbon content (R = 0.90). However, in spite of 20 times higher total carbon contents in the Jeju soils, there was a week negative correlation between the reduction capacity and the carbon content (R = -0.469), suggesting that the reduction capacity of Jeju soils is not mainly controlled by the carbon content and affected by other soil properties. Correlations of the reduction capacity with major elements showed that Al and Fe were closely connected with the reduction capacity in Jeju soil (R = 0.793; R = 0.626 respectively). Moreover, the amounts of Ni, Co and Cr had considerable correlations with the reduction capacity (R = 0.538; R = 0.647; R = 0.468 respectively). In particular, in relation to the behavior of redox-sensitive Cr, the oxidation of the trivalent chromium to mobile and toxic hexavalent chromium can be restricted by the high reduction capacity in Jeju soil. The factors controlling the reduction capacity in Jeju soils may have a close relation with the andic soil properties explained by the presence of considerable allophane and ferrihydrite in the soils.

Yoo Young-kuk's Early Constructivism: Utopianism in (1937) (유영국(劉永國)의 초기 구성주의: <랩소디>(1937)에 나타난 유토피아니즘)

  • 유영아
    • The Journal of Art Theory & Practice
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    • no.9
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    • pp.93-121
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    • 2010
  • This study is about Yoo Young-kuk's early works which show constructivism, especially focus on his debut painting, for the 7th Dokuritsu Bijutsu Kyokai(獨立美術協會, the Independent Fine Arts Association) in Tokyo in 1937. The work was painted 2 years after he had started his study in Japan in 1935. It was the first painting that applied Constructivism. played an important role for Constructivism to be a leading art in his abstraction. After this picture, Yoo was soon devoted to the principles of Constructivism-- Faktura(material), Tektonika (tectonics), Tekhnika(technique), space, construction-- in his painterly reliefs. This article examined why Yoo concentrated on Constructivism for , what the characteristics were, and what influences were on other works from 1935 to 1949. In addition, I investigated in which period was painted and how Constructivism was spread in 1930s and early 1940s in chapter 2. I scrutinized Rhapsody in chapter 3. When Yoo created Japan was under the Fifteen Years War(1931-1945), and a major discourse was the Japanese Spirit at that time. It was connected with construction of an ideal nation which the Japanese ultra-national fascism pursued. This ideological pursuit was intended to unite the Japanese people for total war system and to restore a national dignity which had been fallen down due to Manchurian Incident(1931). Thus, on the hand, Kokusai Bunka Shinkokai(國際文化振興, The Society for International Cultural Relations) and the Nippon Kosaku Bunka Renmei(日本工作文化連盟, Japanese Werkbund) were supported financially by the Japanese government. On the other hand, the government enacted regulations to opposing parties which would distract Japanese people's unification. As for the Japanese art world, the merge of art groups was carried out through remodeling of Teikoku Bijutsuin(帝國美術院, The Imperial Fine Arts Academy) in 1935. This brought out continuous dispute and disorder. Young artists who felt difficulty of entering an entry of Imperial Fine Arts Exhibition repeatedly grouped and disbanded for small art groups to build their standing, which they pursued Surrealism and Abstract art. Among them Constructivism was considered as the latest trend and was popular in craft, design, architecture as well as fine arts. In the year before he painted , Avant-garde theatres including Constructivism theatre were introduced in a feature article of September, 1936 in Atelier, which was dealing with mainly avant-garde arts. Books related with Constructivism were translated into Japanese, and Gestaltung Education had become active since the publication of A Compendium of Gestaltung Education("構成敎育大系"(1934)), Salvador Dali(1904-1989) was also introduced, so Surrealism was drawn more attention by young artists. reflected popular trends. Yoo analyzed the Japanese avant-gardists' archaic taste in the Independent Art Association that he submitted his painting to. And then he entitled 'Rhapsody' which derives from Ancient Greek's epic poetry and deliberately set up images in a scene. In chapter 3, I examined a theme which was planned carefully by sorting favorite images from the Japanese Surrealism. was a result that Yoo Young-kuk observed objectively the phenomenon that young artists dreamt of Utopia or longed for Nostalgia passively and lethargically under wars. And then he otherized himself from that circumstance. First of all, for he used the typical icons of Japanese Surrealism such as the horizon, flowing clouds, and vast plain that were considered stereotypes of Arcadia. He, however distinguished himself form those Japanese Surrealists. He made his own vision about Utopia by referring Lyubov Popova(1889-1924)'s stage design. His objective point of view was expressed by positive and dynamic images of structure and human's actions. Constructivism which was attempted in had an effect on other early constructive works, and the principles of Constructivism were sought hard in reliefs, paintings, and photos.

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The Measurement and Comparison of the Relative Efficiency for Currency Futures Markets : Advanced Currency versus Emerging Currency (통화선물시장의 상대적 효율성 측정과 비교 : 선진통화 대 신흥통화)

  • Kim, Tae-Hyuk;Eom, Cheol-Jun;Kang, Seok-Kyu
    • The Korean Journal of Financial Management
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    • v.25 no.1
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    • pp.1-22
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    • 2008
  • This study is to evaluate, to the extent to, which advanced currency futures and emerging currency futures markets can predict accurately the future spot rate. To this end, Johansen's the maximum-likelihood cointegration method(1988, 1991) is adopted to test the unbiasedness and efficiency hypothesis. Also, this study is to estimate and compare a quantitative measure of relative efficiency as a ratio of the forecast error variance from the best-fitting quasi-error correction model to the forecast error variance of the futures price as predictor of the spot price in advanced currency futures with in emerging currency futures market. Advanced currency futures is British pound and Japan yen. Emerging currency futures includes Korea won, Mexico peso, and Brazil real. The empirical results are summarized as follows : First, the unbiasedness hypothesis is not rejected for Korea won and Japan yen futures exchange rates. This indicates that the emerging currency Korea won and the advanced currency Japan yen futures exchange rates are likely to predict accurately realized spot exchange rate at a maturity date without the trader having to pay a risk premium for the privilege of trading the contract. Second, in emerging currency futures markets, the unbiasedness hypothesis is not rejected for Korea won futures market apart from Mexico peso and Brazil real futures markets. This indicates that in emerging currency futures markets, Korea won futures market is more efficient than Mexico peso and Brazil real futures markets and is likely to predict accurately realized spot exchange rate at a maturity date without risk premium. Third, this findings show that the results of unbiasedness hypothesis tests can provide conflicting finding. according to currency futures class and forecasts horizon period, Fourth, from the best-fitting quasi-error correction model with forecast horizons of 14 days, the findings suggest the Japan yen futures market is 27.06% efficient, the British pound futures market is 26.87% efficient, the Korea won futures market is 20.77% efficient, the Mexico peso futures market is 11.55%, and the Brazil real futures market is 4.45% efficient in the usual order. This indicates that the Korea won-dollar futures market is more efficient than Mexico peso, and Brazil real futures market. It is therefore possible to concludes that the Korea won-dollar currency futures market has relatively high efficiency comparing with Mexico peso and Brazil real futures markets of emerging currency futures markets.

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A Study on Hybrid Characteristics of Public Space in Contemporary Cities Reinterpreted by the Idea of Liminal Space (역공간(Liminal Space) 개념으로 해석한 현대도시 공공공간의 혼성적 특성에 관한 연구)

  • Zoh, Kyung-Jin;Han, So-Young
    • Journal of the Korean Institute of Landscape Architecture
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    • v.39 no.4
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    • pp.49-59
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    • 2011
  • This study is a reinterpretation of characteristics of public space in contemporary cities with a view to liminal space. The conditions of pubic space now cannot be captured through the existing discourses of publicness, and public space. The basic premise of the study is that the idea of liminal space or liminality is useful to grasp the fluid and hybrid attribute of public space in contemporary cities. Liminal space, originally from anthropological studies, is the intermingled stage between two realms and the sustained period of the ritual. The idea has been widely used for various cultural phenomenon and spatial experiences. A literature review on public space and liminal space was carried out. Cases pertaining to public space with a view to liminal space were examined and discussed in detail. Through the careful reading of several public spaces with an angle toward liminal space, the new perspective toward public space will be drawn out. First, we need to emphasize the fluid spectrum of public space rather than the serial stage such as the public, the semi-public, the semi-private, and the private. Second, the idea will contribute to understanding the flexible state depending upon time. What we can learn from case studies is the volatile characteristics in public space as a common phenomenon support its vitality. This interpretation will contribute to the perception of a new horizon of public space. The nature of public space is unpredictable and free. In reality, the spectrum of public space will expand and fluctuate. Ironically, public space can be vitalized through enhancing and activating the private space. The intimate and complicated interface between the two realms is a key issue. The boundary of public space might be redefined to embrace the flexible the fragile nature of changing public space. These research implications will guide the thoughtful design and management of pubic space.