• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.3
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• pp.215-231
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• 2020

Forest landscape models (FLMs) can be used to investigate the complex interactions of various ecological processes and patterns, which makes them useful tools to evaluate how environmental and anthropogenic variables can influence forest ecosystems. However, due to the large spatio-temporal scales in FLMs studies, parameterization and validation can be extremely challenging when applying to new study areas. To address this issue, we focused on the parameterization and application of a spatially explicit forest landscape model, LANDIS-II, to Mt. Gyebang, South Korea, with the use of the National Forest Inventory (NFI) and long-term ecological research (LTER) site data. In this study, we present the followings for the biomass succession extension of LANDIS-II: 1) species-specific and spatial parameters estimation for the biomass succession extension of LANDIS-II, 2) calibration, and 3) application and validation for Mt. Gyebang. For the biomass succession extension, we selected 14 tree species, and parameterized ecoregion map, initial community map, species growth characteristics. We produced ecoregion map using elevation, aspect, and topographic wetness index based on digital elevation model. Initial community map was produced based on NFI and sub-alpine survey data. Tree species growth parameters, such as aboveground net primary production and maximum aboveground biomass, were estimated from PnET-II model based on species physiological factors and environmental variables. Literature data were used to estimate species physiological factors, such as FolN, SLWmax, HalfSat, growing temperature, and shade tolerance. For calibration and validation purposes, we compared species-specific aboveground biomass of model outputs and NFI and sub-alpine survey data and calculated coefficient of determination (R²) and root mean square error (RMSE). The final model performed very well, with 0. 98 R² and 8. 9 RMSE. This study can serve as a foundation for the use of FLMs to other applications such as comparing alternative forest management scenarios and natural disturbance effects.

• Horticultural Science & Technology
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• v.34 no.6
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• pp.871-877
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• 2016

Recycling nutrient solutions in closed hydroponic production systems is usually accompanied by an imbalance of nutrient solutions when concentration is controlled according to electrical conductivity (EC) levels. This study investigated whether it was possible to automatically control the concentrations of five essential elements nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) using only N, K and Ca ion sensors. N, P, K, Ca, and Mg uptake was measured in the nutrient solution, and relationships between absorbed ions were analyzed through twice-repeated experiments in lettuce. Results confirmed that the pattern of $PO_4$ ion uptake was similar that of N, and the pattern of Mg ion uptake was similar that of Ca. $PO_4$ ion uptake was most highly correlated with N, and Mg was most highly correlated with Ca. Regression coefficients of N and $PO_4$ were significantly different at 1.04 and 0.55, respectively, but were similar between Ca and Mg at 0.35 and 0.40, respectively. Additional experiments were conducted to measure nutrient uptake in pak choi and rose plants, both to confirm the results from the first experiment in lettuce, and to assess possible application to other crops. Coefficients of determination both for N and $PO_4$, and Ca and Mg were considerably high ($R^2=0.86$) in cultured pak choi, and similar results were observed in cultured rose ($R^2=0.87$ and 0.73, respectively). Regression coefficients for cultured pak choi were 0.56 and 0.24, respectively, and for rose were 0.51 and 0.16, respectively. Although the results obtained for N and $PO_4$ were not consistent between the lettuce experiments, N and $PO_4$ have similar regression coefficients for all crops. No common coefficient was found between Ca and Mg.

• Journal of the Korean Geographical Society
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• v.31 no.2
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• pp.160-197
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• 1996

The purpose of this study is to review research trends and issues of economic geography in Korea for the last fifty years by sub-fields of agricultural geography, industrial geography, commercial and service geography, and transportation geography. Research in Korean economic geography has progressed significantly in terms of the scope and the number of papers published during the last a half a century. Agricultural geography was a leading field of economic geography in Korea before mid-1970s. Since the mid-1970s, however, agricultural geography has turned over the leading role in economic geography to industrial geography. Classification and structure of agricultural region has been the most popular research theme in Korea, even though diverse topics has been dealt in the research of agricultulal geography in Korea during the last fifty years. In recent years, emphasis is given to study on the dynamics of agricultural region and regional differentiation of part-time farming. It is suggested that the future issues of research in agricultural geography in Korea are agricultural restructuring and changes in agricultural space under the WTO system, changes in rural area and agricultural region with the progress of informatization, changes in agricultural structures and rural society by the increase of part-time farming, governments agricultulal policy and its impacts, competitive advantages of Korean agricultulal products, and environmental impacts of agricultural restructuring. Research in industrial geography has remarkably progressed since the 1980s. Locational changes, regional industrial structure and formation of industrial region were the major topics of interest in the research of industrial geography in Korea before 1980. Since the early 1980s, in addition to the topics which were interested in before 1980, changes of industrial organization and industrial location, changes of production systems and industrial space development of high technology industries and science parks, industrial restructuring and regional economy, foreign direct investments, industrial linkages and industrial districts, and industrial policy and regional development have been the major research themes of industrial geography in Korea. Considerable number of papers has been published both in Korean journals and in foreign journals during this period. Considering global changes in the organization of industrial space, future research should be more focused on firms strategy for regaining competitive advantages, local and global perspectives of industry, industry and environmental changes, in addition to the topics which have been dealt in recent years. Research in commercial and service geography and transportation geography was negligible in Korea before the late 1970s. These two sub-fields in economic geography have begun to develop since 1980s. Periodic markets, structure of commercial area, and distribution of products were the major topics of interest in the 1980s in the commercial and service geography in Korea. In the 1990s, however reserch in producer services has been active with growth of producer services in Korean economy. It is suggested that regional changes with progress of informatization and technology, changes of international trade and regional changes, development of efficient distribution system, role of producer services in regional development, and network of producer services are the major issues to be studied in the future in the field of commercial and service geography in Korea. Commuting, distribution of products, and transportation networks have been the major topics of research in transportation geography in Korea. Diverse quantitative techniques have been applied in the most of the researches in transportation geography. It is required that future studies in transportation geography should also focus on societal and behavioral issues, policy issues regional impacts of new transportation facilities, an analysis of transportation system at the global or international level. Since the 1980s economic geography in Korea has considerably progressed with publication of papers and books. The progress can be regarded as successful in quantitative aspect, but not in quantitative aspects. For the development of Korean economic geography in both quantitative and qualitative aspects, it is necessary to promote international collaborative researches and interdisciplinary cooperations. Attention should also be given to the research on changes in competitive advantages and economic restructuring, changes of economic space with the development of high technology and the progress of informatization. economic development and culture. and foreign regional studies.

• The Korean Journal of Air & Space Law and Policy
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• v.28 no.1
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• pp.3-54
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• 2013

Nowadays, major advanced countries in aviation technology are putting their effort to develop commercial and civil Unmanned Aircraft System(UAS) due to its highly promising market demand in the future. The market scale of commercial and civil UAS is expected to increase up to approximately 8.8 billon U.S. dollars by the year 2020. The usage of commercial and civil UAS covers various areas such as remote sensing, relaying communications, pollution monitoring, fire detection, aerial reconnaissance and photography, coastline monitoring, traffic monitoring and control, disaster control, search and rescue, etc. With the introduction of UAS, changes need to be made on current Air Traffic Management Systems which are focused mainly manned aircrafts to support the operation of UAS. Accordingly, the legislation for the UAS operation should be followed. Currently, ICAO's Unmanned Aircraft System Study Group(UASSG) is leading the standardization process of legislation for UAS operation internationally. However, some advanced countries such as United States, United Kingdom, Australia have adopted its own legislation. Among these countries, United States is most forth going with President Obama signing a bill to integrate UAS into U.S. national airspace by 2015. In case of Korea, legislation for the unmanned aircraft system is just in the beginning stage. There are no regulations regarding the operation of unmanned aircraft in Korea's domestic aviation law except some clauses regarding definition and permission of the unmanned aircraft flight. However, the unmanned aircrafts are currently being used in military and under development for commercial use. In addition, the Ministry of Land, Infrastructure and Transport has a ambitious plan to develop commercial and civil UAS as Korea's most competitive area in aircraft production and export. Thus, Korea is in need of the legislation for the UAS operation domestically. In this regards, I personally think that Korea's domestic legislation for UAS operation will be enacted focusing on following 12 areas : (1)use of airspace, (2)licenses of personnel, (3)certification of airworthiness, (4)definition, (5)classification, (6)equipments and documents, (7)communication, (8)rules of air, (9)training, (10)security, (11)insurance, (12)others. Im parallel with enacting domestic legislation, korea should contribute to the development of international standards for UAS operation by actively participating ICAO's UASSG.

• Korean Journal of Poultry Science
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• v.40 no.3
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• pp.197-205
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• 2013

This study established a method for preserving chicken primordial germ cells (PGCs) that enables long-term storage in liquid nitrogen ($LN_2$) for preservation of the species. The purpose of this study was to compare the effects of Ethylene Glycol (EG) and Propylene Glycol (PG) on viability of cryopreserved PGCs with vitrification in Korean Native Chicken (Ogye), and to fine should be find or to the optimal protocol for PGCs freezing. One of the important components of cryopreservation process is cryopreservation medium that plays a vital role in preventing cellular injury during freeze-thawing. Cryoprotective agents have been known to improve cell viability after freeze-thawing. PGCs obtained from the germinal gonade of 5.5~6 day (stage 28) chick embryos, using the MACS method were suspended in a freezing medium containing a freezing and protecting agents. Gonads were harvested from stage 28 chick embryos and pooled in groups of 10E embryos, contributing gonads to the cell suspension. The gonadal cells, including PGCs, were then frozen in 1 of the following cryoprotectant treatments: 2.5% EG, 5% EG, 10% EG, 2.5% PG, 5% PG, 10% PG, and 0% cryoprotectant as a control. Effects of exposure to vitrification solution and vitrification, with different concentrations of the cryoprotectant solution, were examined. After freezing and thawing, survival rates of the frozen-thawed PGCs from the 0, 2.5, 5, 10 and 15% EG plus FBS treatment were 44.24%, 64.51%, 85.63%, 80.51% and 73.52% (p<0.05), respectively. The viability of PGCs after freeze-thawing was significantly higher for 10% EG plus FBS treatment than for 10% PG + FBS treatment (p<0.05)(85.63% vs 66.81%). Therefore, these systems may contribute in the improvement of cryopreservation for a scarce species in birds preservation. This study established a method for preserving chicken PGC that enables systematic storage and labeling of cryopreserved PGCs in liquid N at a germplasm repository and ease of entry into a database. In the future, the importance for this new technology is that poultry lines can be conserved while work is being conducted on improving the production of germline chimeras.

• Nuclear Engineering and Technology
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• v.39 no.5
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• pp.603-616
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• 2007

Roy Huddle, having invented the coated particle in Harwell 1957, stated in the early 1970s that we know now everything about particles and coatings and should be going over to deal with other problems. This was on the occasion of the Dragon fuel performance information meeting London 1973: How wrong a genius be! It took until 1978 that really good particles were made in Germany, then during the Japanese HTTR production in the 1990s and finally the Chinese 2000-2001 campaign for HTR-10. Here, we present a review of history and present status. Today, good fuel is measured by different standards from the seventies: where $9*10^{-4}$ initial free heavy metal fraction was typical for early AVR carbide fuel and $3*10^{-4}$ initial free heavy metal fraction was acceptable for oxide fuel in THTR, we insist on values more than an order of magnitude below this value today. Half a percent of particle failure at the end-of-irradiation, another ancient standard, is not even acceptable today, even for the most severe accidents. While legislation and licensing has not changed, one of the reasons we insist on these improvements is the preference for passive systems rather than active controls of earlier times. After renewed HTGR interest, we are reporting about the start of new or reactivated coated particle work in several parts of the world, considering the aspects of designs/ traditional and new materials, manufacturing technologies/ quality control quality assurance, irradiation and accident performance, modeling and performance predictions, and fuel cycle aspects and spent fuel treatment. In very general terms, the coated particle should be strong, reliable, retentive, and affordable. These properties have to be quantified and will be eventually optimized for a specific application system. Results obtained so far indicate that the same particle can be used for steam cycle applications with $700-750^{\circ}C$ helium coolant gas exit, for gas turbine applications at $850-900^{\circ}C$ and for process heat/hydrogen generation applications with $950^{\circ}C$ outlet temperatures. There is a clear set of standards for modem high quality fuel in terms of low levels of heavy metal contamination, manufacture-induced particle defects during fuel body and fuel element making, irradiation/accident induced particle failures and limits on fission product release from intact particles. While gas-cooled reactor design is still open-ended with blocks for the prismatic and spherical fuel elements for the pebble-bed design, there is near worldwide agreement on high quality fuel: a $500{\mu}m$ diameter $UO_2$ kernel of 10% enrichment is surrounded by a $100{\mu}m$ thick sacrificial buffer layer to be followed by a dense inner pyrocarbon layer, a high quality silicon carbide layer of $35{\mu}m$ thickness and theoretical density and another outer pyrocarbon layer. Good performance has been demonstrated both under operational and under accident conditions, i.e. to 10% FIMA and maximum $1600^{\circ}C$ afterwards. And it is the wide-ranging demonstration experience that makes this particle superior. Recommendations are made for further work: 1. Generation of data for presently manufactured materials, e.g. SiC strength and strength distribution, PyC creep and shrinkage and many more material data sets. 2. Renewed start of irradiation and accident testing of modem coated particle fuel. 3. Analysis of existing and newly created data with a view to demonstrate satisfactory performance at burnups beyond 10% FIMA and complete fission product retention even in accidents that go beyond $1600^{\circ}C$ for a short period of time. This work should proceed at both national and international level.

• Journal of Korean Society of Archives and Records Management
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• v.3 no.1
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• pp.69-92
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• 2003

Registration and description of records are important elements of processing which provide with the background information of production of records and business-related information. They also enable to search and use the records. In this paper, I examined the Korean registration and description system defined in the Public Records Management Act which directs the records creating agency to register records in creating offices and directs the "professional archives" to make "basic registrations" and "detailed registrations" of the records. In the analysis and comparison of two different registration and description systems with the known international standards of records and archives management, such as ISO15489 and ISAD(G), I intended to evaluate the Korean records and archives management system and suggested recommendations for the renovation of the Korean recordskeeping system. Despite we have unique office business procedures and the culture of officialdom, and despite we have developed our system based on the established business procedures and office culture, it would be preferable to adopt or follow the international standards and established best practices. After the comparative analysis, I recommended some innovations in the filed of registration and description. For instance, in the basic registration. we would better to install an item of "simple contents summary." We may also need the multiple-level description. The fonds level description and the series level description should be introduced to our archival automated management system. We need to establish a Korean standard of description adopting the rules of the ISAD(G) and ISAAR(CPF). Essential requirements for electronic records management, such as contextual and structural information, should be incorporated in the new standard. Documentation of records disposition also should be reinforced to guarantee the authenticity of records and to ensure control of the records. To implement the recommendations for the standard, we need to amend the Public Records Management Act and its Regulations and Rules. Also it is imperative to redesign the GARS integrated archival automated management system.

• Journal of The Korean Association For Science Education
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• v.18 no.4
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• pp.463-472
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• 1998

Biotechnology is the process of using biological system for the production of materials. Genetic engineering, a subset of biotechnology, is the process of altering biological systems by the purposeful manipulation of DNA It is a new field in biology and no topic in biology is more likely to impact our personal lives and is therefore more worthy of our attention and understanding. The purpose of this study was to investigate students' understanding of the concepts of biotechnology, and a test tool which is made up of 20 basic questions was developed for the study. The subject of this study was high school students and the sample size was 486. In order to find out the source of students' misunderstanding, we also analysed high school textbooks and teachers were given the same tool applied to students. Two-way ANOVA was used for the analysis. Major findings of this study are as following; 1. Mean score of students was 41, and there was a significant difference between the scores of boys and girls(p<0.05). Female students scored higher than male students. The variables "region" and "major" had no significant influence. 2. Students' the most misunderstood concepts were "monoclonal antibody" and "gene cloning". Many students thought that a plamid DNA originally has a useful DNA in it, which is apparently wrong. 3. Mean score of teachers was 82, and the variabes of gender and career did not have statistically significant influence on the result(p>0.05). 4. Teachers got the lowest scores on the concepts of "gene therapy", "the accomplishment of biotechnology in agriculture and medicine", and "plasmid DNA". The results of item analysis implied that teachers' misunderstanding might be a part of the sources of students' misunderstaning. 5. Out of 18 basic concepts selected in the study, only 10 concepts were explained well enough in most textbooks. The results of item analysis indicated that textbooks also could be a part of the source of students' misunderstanding.

• Journal of Life Science
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• v.13 no.3
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• pp.333-342
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• 2003

The pathogenic effort of high glucose, possibly in concert with fatty acids, is mediated to vascular complications of diabetes via increased production of reactive oxygen species(ROS), reactive nitrogen species(RNS), and subsequent oxidative stress. This study was carried out to investigate the suppressive effect of buchu(Allium tuberosum) on oxidative stress in streptozotocin(STZ)-induced diabetes in Sprague Dawley male rats. The effect of buchu supplementation (10%) on lipid peroxidation, and antioxidative defense system in blood and liver was compared among normal rats fed basal diet(normal) and diabetic rats fed basal diet(DM-control) or 10% buchu-supplemented diet(DM-buchu). Diabetes was experimentally induced by the femoral muscle injection of 50 mg STZ per kg of body weight. Animals were sacrificed after 4 wks of experimental diets feeding. The induction of diabetes by STZ elevated the level of lipid peroxidation represented by thiobarbituric acid-reactive substances(TBARS) and conjugated dienes in plasma, LDL, liver, and erythrocytes. 10% buchu-supplemented diet significantly reduced the levels of conjugated dienes in erythrocytes(p<0.05) and lowered TBARS in liver and LDL to the levels of control. Induction of diabetes by STZ elevated Mn-superoxide dismutase(Mn-SOD) activity and lowered activities of glutathionine reductase(GSH-red) and glutathionine peroxidase(GSH-px). Catalase activity was not affected by the induction of diabetes by STZ. However, buchu supplementation to diabetic rats significantly elevated catalase activity(p<0.05) and slightly elevated GSH-px and GSH-red activities in liver. GSH levels of blood and liver were lowered or not changed by induction of diabetes by STZ, respectively, while buchu supplementation to diabetic rats significantly elevated hepatic GSH level (p<0.05). In conclusion, it can be concluded that buchu might be a food source to attenuate oxidative stress in diabetic patients by inhibiting lipid peroxidation, by increasing hepatic GSH level, and by inducing anti-oxidative enzyme systems.

• Journal of Animal Science and Technology
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• v.50 no.3
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• pp.391-400
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• 2008

Odor management is significantly concerned with sustainable livestock production because odor nuisance is a primary cause for complaint to neighbors. This study was conducted to measure the concentration of odorous compounds, odor intensity, and odor offensiveness at unit process in animal waste treatment facility combined composting and methane fermentation process by an instrumental analysis and direct olfactory method. Ammonia, sulfur-containing compounds, and volatile fatty acid were analyzed at each process units and boundary area in summer and winter, respectively. Higher concentration of odorants occurred in the summer than in the winter due to high ambient temperature. The maximum concentration of odorants was detected in composting pile when mixed manure was being turned followed by inlet, curing, outlet, and screen & packing process. Highest concentration of detected odorous compounds was ammonia ranging from 3.4 to 224.7 ppm. Among the sulfur-containing compounds measured, hydrogen sulfide was a maximum level of 2.3 ppm and most of them exceeded reported odor detection thresholds. Acetic acid was the largest proportion of VFA generated, reaching a maximum of 51 to 89%, followed by propionic and butyric acid at 1.9 to 35% and 1.8 to 15%, respectively. Malodor assessment by a human panel appeared a similar tendency in instrumental analysis data. Odor quotient for predicting major odor-causing compounds was calculated by dividing concentrations measured in process units by odor detection thresholds. In the composting process, hydrogen sulfide, ammonia, dimethyl sulfide, and methyl mercaptan were deeply associated with odor-causing compounds, while the major malodor compounds in the inlet process were methyl mercaptan, hydrogen sulfide, and butyric acid.