• Journal of the Korean Society of International Agriculture
• /
• v.30 no.4
• /
• pp.328-338
• /
• 2018

Central Asia (Uzbekistan, Kazakhstan, Kyrgyzstan) is a hot and arid continental climate, with most areas (68%) consisting of barren vegetation, desert, and meadows. The main agricultural areas for crop production include irrigated farmland, non-irrigated farmland, grassland, prairie and mountain. We are experiencing climate change with recent climate variability increasing. Agriculture is one of major economic sectors and provides a means of livings for the rural population of Central Asia, especially the poor. In the past two decades, Central Asia has experienced a high population growth rate, with Kazakhstan at 16.8%, Uzbekistan at 34.5% and Kyrgyzstan at 28.4%. As a major industry, Kazakhstan has the largest share of exports of agricultural products followed by petroleum, mineral resources, steel, and chemicals. Uzbekistan is the fifth largest cotton exporter as well as the sixth largest cotton producer in the world. Kyrgyzstan exports ores, stones, cultured pearls, and minerals. These three countries are rich in mineral resources, agricultural products, and energy resources. However, not only do they have difficulties in economic development due to the weakness of logistics and industrial infrastructure, but they also have imperceptible cooperation and investment among countries due to insufficient research and development. Through this study, we will investigate national outlook, economic indicators, major agricultural products, import and export status, and agricultural technology cooperation status, and study how Korean agricultural industry advances into these countries through SWOT analysis. Through this, we hope to contribute to the basic data of Central Asian studies and cooperation and investment in agriculture in each country. In addition, in order to increase cooperative exchange and investment in these countries, we will prepare a Central Asia logistics hub for the rapidly changing interKorean railroad era.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.8
• /
• pp.215-225
• /
• 2016

This study seeks to find an alternative to the requirement for proving the competitiveness of Korean performing arts before entering into the overseas market by deriving the factors causing entry into the market to be delayed based on an analysis of the current status. Between 2007 to 2014, the overseas revenues from Korean performing arts increased by 16.4% compared to the total amount of financial support, as the number of free performances given overseas and the average guaranteed number of performances overseas are both at a standstill. Also, the size of the audience increased by a mere 3.3 times, which is an even lower growth rate than that for the number of performances, 3.8 times, during the same period. Furthermore, the audience size per unit is suffering from long-term stagnation. The main causes are as follows: 1) applying one-dimensional methods to performing arts exchanges and expanding the overseas market, 2) the existing confused concepts between profit and non-profit contents, 3) the weaknesses of the market expansion strategy, because of programming practices focusing on providers, such as presenters and producers, rather than consumers. As a result, the necessary basic research, including consumer surveys, has not been done yet. In order to understand the implications of this analysis and solve the problem of the delayed overseas expansion of Korean performing arts, the Korean wave industry was examined as a representative example. Consumer surveys for the performing arts, possibly benchmarked to the "Korean Wave Consumer Survey Index (KWCSI)", are expected to be done in the near future. In addition, through the development of a specific consumer index of the performing arts, customized marketing strategies by continent and country need to be established. This empirical study of the overseas expansion of performing arts can be utilized as a bridge between the academic and real worlds. This work may also enable a variety of strategies to be established for the overseas expansion of the performing arts.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.36 no.5
• /
• pp.394-406
• /
• 1991

It was proved that cold tolerance of rice plants at the young microspore stage was affected by water temperature and nitrogen application from the spikelet differentiation stage to the young microspore stage, and this mechanism could be explained in the point of view of pollen developmental physiology. The cold tolerance of rice plants at the young microspore stage was severely affected by water temperature (Previous water temperature) and nitrogen application(Previous nitrogen application) from the spikelet differentiation stage to the spikelet differentiation stage. Although the duration is only 10 days or so from the spikelet differentiation stage to the young microspore stage, these days are very important period to confirm the cold tolerance of rice plants at the young microspore stage. The higher previous water temperature up to $25^{\circ}C$ and the deeper previous water depth up to 10cm caused the more cold tolerance of rice plants. Water irrigation of 10cm before the cretical stage showed lower cool injury than that of water irrigation of 20cm during the critical stage. The preventive effect of cool injury by combined treatment of the deep water irrigation before and during the critical stage was not additive but synergistic. The cold tolerance of rice plants grown in previous heavy nitrogen level was rapidly decreased when nitrogen content of leaf blade at the young microspore stage was excessive over the critical nitrogen level. Nitrogen content of leaf blade at the changing point of cold tolerance was estimated as about 3.5% for Japonica cultivars and about 2.5% for Indica x Japonica cultuvars. It is considered that these critical nitrogen contents of leaf blade can be used as a index of the safe critical nitrogen level for the preventive practices to cool injury. It was summarized that increase of engorged pollens per anther by high previous water temperature resulted from the increase of number of differentiated microspores per anther, otherwise, the increase of engorged pollens by the decrease of previous nitrogen level was caused by the decrease of the number of aborted microspores per anther.

• Journal of Intelligence and Information Systems
• /
• v.26 no.1
• /
• pp.135-149
• /
• 2020

Artificial intelligences are changing world. Financial market is also not an exception. Robo-Advisor is actively being developed, making up the weakness of traditional asset allocation methods and replacing the parts that are difficult for the traditional methods. It makes automated investment decisions with artificial intelligence algorithms and is used with various asset allocation models such as mean-variance model, Black-Litterman model and risk parity model. Risk parity model is a typical risk-based asset allocation model which is focused on the volatility of assets. It avoids investment risk structurally. So it has stability in the management of large size fund and it has been widely used in financial field. XGBoost model is a parallel tree-boosting method. It is an optimized gradient boosting model designed to be highly efficient and flexible. It not only makes billions of examples in limited memory environments but is also very fast to learn compared to traditional boosting methods. It is frequently used in various fields of data analysis and has a lot of advantages. So in this study, we propose a new asset allocation model that combines risk parity model and XGBoost machine learning model. This model uses XGBoost to predict the risk of assets and applies the predictive risk to the process of covariance estimation. There are estimated errors between the estimation period and the actual investment period because the optimized asset allocation model estimates the proportion of investments based on historical data. these estimated errors adversely affect the optimized portfolio performance. This study aims to improve the stability and portfolio performance of the model by predicting the volatility of the next investment period and reducing estimated errors of optimized asset allocation model. As a result, it narrows the gap between theory and practice and proposes a more advanced asset allocation model. In this study, we used the Korean stock market price data for a total of 17 years from 2003 to 2019 for the empirical test of the suggested model. The data sets are specifically composed of energy, finance, IT, industrial, material, telecommunication, utility, consumer, health care and staple sectors. We accumulated the value of prediction using moving-window method by 1,000 in-sample and 20 out-of-sample, so we produced a total of 154 rebalancing back-testing results. We analyzed portfolio performance in terms of cumulative rate of return and got a lot of sample data because of long period results. Comparing with traditional risk parity model, this experiment recorded improvements in both cumulative yield and reduction of estimated errors. The total cumulative return is 45.748%, about 5% higher than that of risk parity model and also the estimated errors are reduced in 9 out of 10 industry sectors. The reduction of estimated errors increases stability of the model and makes it easy to apply in practical investment. The results of the experiment showed improvement of portfolio performance by reducing the estimated errors of the optimized asset allocation model. Many financial models and asset allocation models are limited in practical investment because of the most fundamental question of whether the past characteristics of assets will continue into the future in the changing financial market. However, this study not only takes advantage of traditional asset allocation models, but also supplements the limitations of traditional methods and increases stability by predicting the risks of assets with the latest algorithm. There are various studies on parametric estimation methods to reduce the estimated errors in the portfolio optimization. We also suggested a new method to reduce estimated errors in optimized asset allocation model using machine learning. So this study is meaningful in that it proposes an advanced artificial intelligence asset allocation model for the fast-developing financial markets.

• Journal of agricultural medicine and community health
• /
• v.37 no.2
• /
• pp.84-95
• /
• 2012

Background: In Korea, private health insurance has neglected to induce externality on national health insurance by moral hazard. Therefore, we conducted this study in order to explore the influence of private health insurance on unnecessary medical utilization among patients with cervical or lumbar sprain. Method: The study examined a population of 449 patients (admission, 384; out-patient; 85) diagnosed with simple cervical or lumbar sprain without neurological symptoms at 20 small hospitals or clinics in Gwangju and Jeollanam provinces from Jul. 1 to Aug. 31 2008. The data were collected using structured, self-administrated questionnaire which collected information such as whether or not the patient was admitted (as a dependent variable), whether or not they had private health insurance (as a independent variable), and covariates such as socio-demographic characteristics, the factors related to the sprain, and characteristics of the insurance provider. Results: From hierarchical multiple logistic regression analysis, it was found that the admission rate of patient with private health insurance was higher than that those without it (Odds ratio=3.31, 95% Confidence interval; 1.14-9.58), meaning that private health insurance was an independent factor influencing the admission of patients with these conditions. Other determinants of admission were patient age and physician referral. Conclusions: This study is the first empirical study to explore the influence of private health insurance on inducing moral hazard in admission services, specifically among patients with cervical or lumbar sprain. Regulation of benefits provided by private health insurance may be necessary, as the effect of this moral hazard may mean existence of externality.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.13 no.4
• /
• pp.89-99
• /
• 2005

The golf courses more than about 200 are operating in Korea. From the golf courses, a great amount of turfgrass clippings tend to increase, steadily. Materials used in the experiment were Creeping Bentgrass(CB), Kentucky Bluegrass(KB), Korean Lawngrass(KL), rice bran and composted chicken drop. Treatments are CB, KB, and KL. The temperature during the composting of all treatments increased rapidly and reached at the highest temperature($57.9^{\circ}C$, $67.8^{\circ}C$, $74.3^{\circ}C$) within 20 days, and then stabilized to the range of $35.2{\sim}41.6^{\circ}C$ at the 30th day. The pH values of all treatments decreased on the first day. However, they were increased rapidly after three days and decreased again on 10~20 days. The pH values of all treatments at the final day were stabilized to the low alkali levels. The contents of total carbon during the period of composting tend to decrease and total nitrogen was increased for factor of reduction of volume. CEC value of all treatments during the period of composting tends to increase. The round paper chromatogram of extracted solution of KL sample was the sharpest and clearest among all treatments. The G.I. values of CB, KB, and KL in 30th day of composting were about 95.1, 77.7, and 98.7 in germination test using chinese cabbage, respectively. Conclusively, all turfgrass clippings used in this experiment were composted well, suitable as composting products standardized by KSC. The maturity of the final compost samples is best in KL, followed by CB and KB treatments. The turfgrass compost can contribute to the plant cultivation for environment-friendly farm, and the results of this study can become the basic data of turfgrass clippings compost. Further research on the mixing ratio of each material is required to produce compost of good quality.

• Journal of Intelligence and Information Systems
• /
• v.24 no.2
• /
• pp.59-83
• /
• 2018

With the increasing importance of sentiment analysis to grasp the needs of customers and the public, various types of deep learning models have been actively applied to English texts. In the sentiment analysis of English texts by deep learning, natural language sentences included in training and test datasets are usually converted into sequences of word vectors before being entered into the deep learning models. In this case, word vectors generally refer to vector representations of words obtained through splitting a sentence by space characters. There are several ways to derive word vectors, one of which is Word2Vec used for producing the 300 dimensional Google word vectors from about 100 billion words of Google News data. They have been widely used in the studies of sentiment analysis of reviews from various fields such as restaurants, movies, laptops, cameras, etc. Unlike English, morpheme plays an essential role in sentiment analysis and sentence structure analysis in Korean, which is a typical agglutinative language with developed postpositions and endings. A morpheme can be defined as the smallest meaningful unit of a language, and a word consists of one or more morphemes. For example, for a word '예쁘고', the morphemes are '예쁘(= adjective)' and '고(=connective ending)'. Reflecting the significance of Korean morphemes, it seems reasonable to adopt the morphemes as a basic unit in Korean sentiment analysis. Therefore, in this study, we use 'morpheme vector' as an input to a deep learning model rather than 'word vector' which is mainly used in English text. The morpheme vector refers to a vector representation for the morpheme and can be derived by applying an existent word vector derivation mechanism to the sentences divided into constituent morphemes. By the way, here come some questions as follows. What is the desirable range of POS(Part-Of-Speech) tags when deriving morpheme vectors for improving the classification accuracy of a deep learning model? Is it proper to apply a typical word vector model which primarily relies on the form of words to Korean with a high homonym ratio? Will the text preprocessing such as correcting spelling or spacing errors affect the classification accuracy, especially when drawing morpheme vectors from Korean product reviews with a lot of grammatical mistakes and variations? We seek to find empirical answers to these fundamental issues, which may be encountered first when applying various deep learning models to Korean texts. As a starting point, we summarized these issues as three central research questions as follows. First, which is better effective, to use morpheme vectors from grammatically correct texts of other domain than the analysis target, or to use morpheme vectors from considerably ungrammatical texts of the same domain, as the initial input of a deep learning model? Second, what is an appropriate morpheme vector derivation method for Korean regarding the range of POS tags, homonym, text preprocessing, minimum frequency? Third, can we get a satisfactory level of classification accuracy when applying deep learning to Korean sentiment analysis? As an approach to these research questions, we generate various types of morpheme vectors reflecting the research questions and then compare the classification accuracy through a non-static CNN(Convolutional Neural Network) model taking in the morpheme vectors. As for training and test datasets, Naver Shopping's 17,260 cosmetics product reviews are used. To derive morpheme vectors, we use data from the same domain as the target one and data from other domain; Naver shopping's about 2 million cosmetics product reviews and 520,000 Naver News data arguably corresponding to Google's News data. The six primary sets of morpheme vectors constructed in this study differ in terms of the following three criteria. First, they come from two types of data source; Naver news of high grammatical correctness and Naver shopping's cosmetics product reviews of low grammatical correctness. Second, they are distinguished in the degree of data preprocessing, namely, only splitting sentences or up to additional spelling and spacing corrections after sentence separation. Third, they vary concerning the form of input fed into a word vector model; whether the morphemes themselves are entered into a word vector model or with their POS tags attached. The morpheme vectors further vary depending on the consideration range of POS tags, the minimum frequency of morphemes included, and the random initialization range. All morpheme vectors are derived through CBOW(Continuous Bag-Of-Words) model with the context window 5 and the vector dimension 300. It seems that utilizing the same domain text even with a lower degree of grammatical correctness, performing spelling and spacing corrections as well as sentence splitting, and incorporating morphemes of any POS tags including incomprehensible category lead to the better classification accuracy. The POS tag attachment, which is devised for the high proportion of homonyms in Korean, and the minimum frequency standard for the morpheme to be included seem not to have any definite influence on the classification accuracy.

• Journal of the Korean Wood Science and Technology
• /
• v.10 no.3
• /
• pp.13-44
• /
• 1982

1. Since long time ago, it has been talked about that soaking wood into water for a long time would be profitable for the decreasing of defects such as checking, cupping and bow due to the undue-shrinking and swelling. There are, however, no any actual data providing this fact definitly, although there are some guesses that water soluble extractives might effect on this problem. On the other hand, this is a few work which has been done about the effect of water soluble extractives upon the some physical properties of wood and that it might be related to the above mentioned problem. If man does account for that whether soaking wood into water for a long time would be profitable for the decreasing of defects due to the undue-shrinking and swelling in comparison with unsoaking wood or not, it may bring a great contribution on the reasonable uses of wood. To account for the effect of water soluble extractives upon physical properties of wood, this study has been made at the wood technology laboratory, School of Forestry, Yale university, under competent guidance of Dr. F. F. Wangaard, with the following three different species which had been provided at the same laboratory. 1. Pinus strobus 2. Quercus borealis 3. Hymenaea courbaril 2. The physical properties investigated in this study are as follows. a. Equilibrium moisture content at different relative humidity conditions. b. Shrinkage value from gre condition to different relative humidity conditions and oven dry condition. c. Swelling value from oven dry condition to different relative humidity conditions. d. Specific gravity 3. In order to investigate the effect of water soluble extractives upon physical properties of wood, the experiment has been carried out with two differently treated specimens, that is, one has been treated into water and the other into sugar solution, and with controlled specimens. 4. The quantity of water soluble extractives of each species and the group of chemical compounds in the extracted liquid from each species have shown in Table 36. Between species, there is some difference in quantity of extractives and group of chemical compounds. 5. In the case of equilibrium moisture contents at different relative humidity condition, (a) Except the desorption case at 80% R. H. C. (Relative Humidity Condition), there is a definite line between untreated specimens and treated specimens that is, untreated specimens hold water more than treated specimens at the same R.H.C. (b) The specimens treated into sugar solution have shown almost the same tendency in results compared with the untreated specimens. (c) Between species, there is no any definite relation in equilibrium moisture content each other, however E. M. C. in heartwood of pine is lesser than in sapwood. This might cause from the difference of wood anatomical structure. 6. In the case of shrinkage, (a) The shrinkage value of the treated specimen into water is more than that of the untreated specimens, except anyone case of heartwood of pine at 80% R. H. C. (b) The shrinkage value of treated specimens in the sugar solution is less than that of the others and has almost the same tendency to the untreated specimens. It would mean that the penetration of some sugar into the wood can decrease the shrinkage value of wood. (c) Between species, the shrinkage value of heartwood of pine is less than sapwood of the same, shrinkage value of oak is the largest, Hymenaea is lesser than oak and more than pine. (d) Directional difference of shrinkage value through all species can also see as other all kind of species previously tested. (e) There is a definite relation in between the difference of shrinkage value of treated and untreated specimens and amount of extractives, that is, increasing extractives gives increasing the difference of shrinkage value between treated and untreated specimens. 7. In the case of swelling, (a) The swelling value of treated specimens is greater than that of the untreated specimens through all cases. (b) In comparison with the tangential direction and radial direction, the swelling value of tangential direction is larger than that of radial direction in the same species. (c) Between species, the largest one in swelling values is oak and the smallest pine heartwood, there are also a tendency that species which shrink more swell also more and, on the contrary, species which shrink lesser swell also lesser than the others. 8. In the case of specific gravity, (a) The specific gravity of the treated specimens is larger than that of untreated specimens. This reversed value between treated and untreated specimens has been resulted from the volume of specimen of oven dry condition. (b) Between species, there are differences, that is, the specific gravity of Hymenaea is the largest one and the sapwood of pine is the smallest. 9. Through this investigation, it has been concluded that soaking wood into plain water before use without any special consideration may bring more hastful results than unsoaking for use of wood. However soaking wood into the some specially provided solutions such as salt water or inorganic matter may be dissolved in it, can be profitable for the decreasing shrinkage and swelling, checking, shaking and bow etc. if soaking wood into plain water might bring the decreasing defects, it might come from even shrinking and swelling through all dimension.

• Journal of the Korean Geotechnical Society
• /
• v.31 no.5
• /
• pp.5-21
• /
• 2015

An energy pile is a novel type of ground heat exchangers (GHEX's) which sets up heat exchange pipes inside a pile foundation, and allows to circulate a working fluid through the pipe for exchanging thermal energy with the surrounding ground stratum. Using existing foundation structure, the energy pile can function not only as a structural foundation but also as a GHEX. In this paper, six full-scale energy piles were constructed in a test bed with various configurations of the heat exchange pipe inside large-diameter cast-in-place piles, that is, three parallel U-type heat exchangers (5, 8 and 10 pairs), two coil type heat exchangers (with a 500 mm and 200 mm pitch), and one S-type heat exchanger. During constructing the energy piles, the constructability of each energy pile was evaluated with consideration of the installation time, the number of workers and any difficulty for installing. In order to evaluate the thermal performance of energy piles, the thermal performance tests were carried out by applying intermittent (8 hours operating-16 hours pause) artificial cooling operation to simulate a cooling load for commercial buildings. Through the thermal performance tests, the heat exchange rates of the six energy piles were evaluated in terms of the heat exchange amount normalized with the length of energy pile and/or the length of heat exchange pipe. Finally, the economic feasibility of energy pile was evaluated according to the various types of heat exchange pipe by calculating demanded expenses per 1 W/m based on the thermal performance test results along with the market value of heat exchange pipes and labor cost.

• Journal of Soil and Groundwater Environment
• /
• v.7 no.4
• /
• pp.77-86
• /
• 2002

Surfactant enhanced in-situ soil flushing was performed to remediate the soil and groundwater at an oil contaminated site, where had been used as a military vehicle repair area for 40 years. A section from the contaminated site (4.5 m $\times$ 4.5 m $\times$ 6.0 m) was selected for the research, which was composed of heterogeneous sandy and silt-sandy soils with average $K_d$ of 2.0$\times$$10^{-4}$cm/sec. Two percent of sorbitan monooleate (POE 20) and 0.07% of iso-prophyl alcohol were mixed for the surfactant solution and 3 pore volumes of surfactant solution were injected to remove oil from the contaminated section. Four injection wells and two extraction wells were built in the section to flush surfactant solution. Water samples taken from extraction wells and the storage tank were analyzed on a gas-chromatography (GC) for TPH concentration in the effluent with different time. Five pore volumes of solution were extracted while TPH concentration in soil and groundwater at the section were below the Waste Water Discharge Limit (WWDL). The effluent TPH concentration from wells with only water flushing was below 10 ppm. However, the effluent concentration using surfactant solution flushing increased to 1751 ppm, which was more than 170 times compared with the concentration with only water flushing. Total 18.5 kg of oil (TPH) was removed from the soil and groundwater at the section. The concentration of heavy metals in the effluent solution also increased with the increase of TPH concentration, suggesting that the surfactant enhanced in-situ flushing be available to remove not only oil but heavy metals from contaminated sites. The removal efficiency of surfactant enhanced in-situ flushing was investigated at the real contaminated site in Korea. Results suggest that in-situ soil flushing could be a successful process to remediate contaminated sites distributed in Korea.