• Journal of Korea Foresty Energy
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• v.21 no.2
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• pp.51-61
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• 2002

This study was conducted to investigate and compare species composition, stand structure, and growth pattern for two different sites in which silvopastoral system has been taking place. One site was the pasture area where a number of trees were removed and grasses were planted for cattle grazing, and the other site was the deciduous forest that has been established by ecological succession. The results were as follows: 1. Nine tree species were present equally in the pasture area and the deciduous forest. Of these species, seven tree species were growing in common for two sites. However, the species composition, including density and frequency, was varied by sites. 2. The number of stems per hectare in the pasture area was 71, and that in the deciduous forest was 1,433, having shown the big difference. It is estimated that, considering the growth rate, better grown trees were remained at the time of harvesting in 1996. 3. The growth of diameter, height, and basal area in the pasture area was superior to that in the nearby deciduous forest. In spite of higher values of diameter and height, the timber volume of pasture area per unit area was less than 15% of that in the deciduous forest. 4. Providing sufficient growing space, the pasture area supported higher values of diameter and height. The wider growing space also had influence on the expansion of crown of trees by the result of deliquescent growth pattern. From this point of view, more research would be needed to establish appropriate number of trees for silvopastoral system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.373-376
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• 2018

Traditional paprika smart farm systems are often harmful to paprika growth because they are set to follow the values of several sensors to the reference value, so the system is often unable to make optimal judgement. Using decision tree techniques, the expert system for the paprika smart farm is designed to create a control system with a decision-making structure similar to that of farmers using data generated by factors that depend on their surroundings. With the current smart farm control system, it is essential for farmers to intervene in the surrounding environment because it is designed to follow sensor values to the reference values set by the farmer. To solve this problem even slightly, it is going to obtain environmental data and design controllers that apply decision tree method. The expert system is established for complex control by selecting the most influential environmental factors before controlling the paprika smart farm equipment, including criteria for selecting decisions by farmers. The study predicts that each environmental element will be a standard when creating smart farms for professionals because of the interrelationships of data, and more surrounding environmental factors affecting growth.

• Korean Journal of Environment and Ecology
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• v.7 no.2
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• pp.187-191
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• 1994

A mixed forest community in Tokyusan was studied to determine the adequate plot area of tree stratum for investigating forest community structure. Nineteen nested plots were set up in the studied forest community, and species-area curve and performance curve were established. According to species-area curve, the minimum plot area where a given percentage increase in plot area produced less than the same percentage increase in number of species was 500$m^2$. The minimum plot area where a given percentage increase in plot area produced less than the half of the percentage increase in number of species was 1,000$m^2$. According to performance curve of the importance values of the major species, the minimum plot area where the importance value of the major species was distinguished from each other was 900$m^2$, and the minimum plot area was 500$m^2$ except for a big tree of Pinus densiflora distributed unexpectedly. According to performance curve of species diversity, the minimum plot area was 400$m^2$. Similarity indices between plot area above 900$m^2$ and total plot area were more than 90% and similarity indices between plot area above 400$m^2$ and total plot area were more than 85%. It may be as a conclusion that minimum plot area was generally about 500$m^2$ and in case of requiring more accuracy, minimum plot area was about 1,000$m^2$.

• Korean Journal of Heritage: History & Science
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• v.38
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• pp.285-303
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• 2005

Through the excavated excellent articles of the Tang era, we have considered the building techniques and styles of a square pavilion, an octagonal pavilion, a miniature hill, a pond, etc., could read building techniques of the scenic structures on ancient literatures including records and additionally about their poetical life at that time and inquired into the arrangement, structure, building techniques, etc. of a miniature hill, a pond, a pavilion, a flowerplant, etc., on Nakyangmyungwonki. Thus, under the research on the private landscape architecture, especially the nobility gardening, around excavated excellent articles and literatures, 'A miniature hill(假山) and a pond for landscaping views formed the center of a garden, and additionally a pavilion was built and flowerplants were set. The miniature hill of laying stones and having a carven, steeping, stratifying, looking like dyed green and birds' singing among hills and eating water on the lakeshore${\ldots}$' was expressed. The pond of digging in the ground and conducting water had its water system developed. There were several kinds of pavilions such as 廳, 堂, 館, 亭, 臺, 樓, 閣, 榭, etc. As examples of landscaping plants, there were a bamboo, a lotus flower, a peony, aromatic trees a pine, a korean spindle tree, a big cone pine, an empress tree, a wild walnut, a peach, a plum, a Japanese apricot tree, an apricot tree, a chrysanthemum, arrowroot vines, etc. Thus, the garden of the Tang era, abundant, diverse and excellent, enjoyed the prime of the period of prosperity. Due to cultural exchange, it is supposed that the period of united Shilla of the same age would meet with the period of prosperity in the developmental history of Korea landscape, based on the nobility garden system '4 different dwelling-houses every season on a record "四節游宅"'.

• Convergence Security Journal
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• v.18 no.1
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• pp.19-31
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• 2018

As the ICT technologies advance, the unprecedently large amount of digital data is created, transferred, stored, and utilized in every industry. With the data scale extension and the applying technologies advancement, the new services emerging from the use of large scale data make our living more convenient and useful. But the cybercrimes such as data forgery and/or change of data generation time are also increasing. For the data security against the cybercrimes, the technology for data integrity and the time verification are necessary. Today, public key based signature technology is the most commonly used. But a lot of costly system resources and the additional infra to manage the certificates and keys for using it make it impractical to use in the large-scale data environment. In this research, a new and far less system resources consuming signature technology for large scale data, based on the Hash Function and Merkle tree, is introduced. An improved method for processing the distributed hash trees is also suggested to mitigate the disruptions by server failures. The prototype system was implemented, and its performance was evaluated. The results show that the technology can be effectively used in a variety of areas like cloud computing, IoT, big data, fin-tech, etc., which produce a large-scale data.

• The Journal of Engineering Geology
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• v.32 no.2
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• pp.221-239
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• 2022

Unknown geotechnical characteristics are key challenges in the design of piles for the plant, civil and building works. Although the N-values which were read through the standard penetration test are important, those N-values of the whole area are not likely acquired in common practice. In this study, the N-value is predicted by means of regression analysis with artificial intelligence (AI). Big data is important to improve learning performance of AI, so circular augmentation method is applied to build up the big data at the current study. The optimal model was chosen among applied AI algorithms, such as artificial neural network, decision tree and auto machine learning. To select optimal model among the above three AI algorithms is to minimize the margin of error. To evaluate the method, actual data and predicted data of six performed projects in Poland, Indonesia and Malaysia were compared. As a result of this study, the AI prediction of this method is proven to be reliable. Therefore, it is realized that the geotechnical characteristics of non-boring points were predictable and the optimal arrangement of structure could be achieved utilizing three dimensional N-value distribution map.

• Journal of the Korea Society of Computer and Information
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• v.25 no.10
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• pp.87-94
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• 2020

Social reviews such as SNS feeds and blog articles have been widely used to extract keywords reflecting opinions and complaints from users' perspective, and often include proper nouns or new words reflecting recent trends. In general, these words are not included in a dictionary, so conventional morphological analyzers may not detect and extract those words from the reviews properly. In addition, due to their high processing time, it is inadequate to provide analysis results in a timely manner. This paper presents a method for efficient keyword extraction from social reviews based on the notion of cohesion scoring. Cohesion scores can be calculated based on word frequencies, so keyword extraction can be performed without a dictionary when using it. On the other hand, their accuracy can be degraded when input data with poor spacing is given. Regarding this, an algorithm is presented which improves the existing cohesion scoring mechanism using the structure of a word tree. Our experiment results show that it took only 0.008 seconds to extract keywords from 1,000 reviews in the proposed method while resulting in 15.5% error ratio which is better than the existing morphological analyzers.

• Journal of the Korean Data and Information Science Society
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• v.26 no.3
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• pp.611-618
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• 2015

By Wikipedia, big data is a broad term for data sets so large or complex that traditional data processing applications are inadequate. Data mining is the computational process of discovering patterns in huge data sets involving methods at the intersection of association rule, decision tree, clustering, artificial intelligence, machine learning. Association rule is a well researched method for discovering interesting relationships between itemsets in huge databases and has been applied in various fields. There are positive, negative, and inverse association rules according to the direction of association. If you want to set the evaluation criteria of association rule, it may be desirable to consider three types of association rules at the same time. To this end, we proposed a balanced comparative confidence considering sensitivity, specificity, false positive, and false negative, checked the conditions for association threshold by Piatetsky-Shapiro, and compared it with comparative confidence and inversely comparative confidence through a few experiments.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.655-658
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• 2020

최근 IT 기술의 발달로 태블릿, 스마트폰과 같은 다양한 디바이스로 손쉽게 음악을 감상할 수 있다. 하지만 최근 이런 기술 발달과는 다르게 사용자가 원하는 음악을 검색하는 방법은 고전적인 형태에서 벗어나지 않고 있다. 기존 음악 검색 방법은 텍스트 기반, 내용 기반, 소비자 감성 기반의 음악 추천 검색 방법이 있으며 저장된 메타 데이터를 이용하여 사용자의 질의에 대한 결과만 제공할 뿐 사용자의 경험 정보를 고려하지 않는다. 그리고 기존 플랫폼들은 사용자가 최근 많이 들은 가수, 장르, 분위기를 종합하여 사용자에게 어울리는 음악을 추천을 할 뿐 사용자의 경험정보를 고려하여 음악을 추천하지는 않는다. 본 논문에서는 사용자의 경험 정보를 활용하여 사용자 맞춤형 음악 추천 시스템을 제안한다. 본 시스템은 사용자의 현재 기분 정보, 주변 날씨 정보 등을 입력 받는다. 이후, 경험 정보를 기반으로 결정 트리를 통해 사용자 요구 기반의 음악 추천 시스템을 구축하였다.

• Journal of the Korean Society of Tobacco Science
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• v.16 no.2
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• pp.181-190
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• 1994

Various active carbons were made from plant sources of coconut shell, pine tree, oak tree and lignite coal. Pore characteristics of these adsorbents were investigated. 1, With increasing activation time, specific surface area and pore volume increased, but the development of micropores was limited at a certain level. The average pore diameter, by BET, of coconut active carbon was 15.5-21.8$\AA$ and that of lignite carbon was 15.6-31.3$\AA$. The pore diameters of silica-gel, sepiolite and zeolite was 30.9$\AA$, 58.6$\AA$ and 55.7$\AA$, respectively. 2. The Horvath - Kawazoe micropore diameter of coconut shell active carbon was under 10.5$\AA$ and that of the other active carbon was under 20.9$\AA$ but silica-gel 33$\AA$, sepiolite 103 $\AA$ and zeolite was unexpectedly large to be 175$\AA$. From the difference between BET micropore diameter and Howath - Kawazoe diameter, it could be said that silica - gel has comparatively uniform pore diameter but sepiolite and zeolite have very uneven diameter. 3. Total pore volume of coconut shell active carbon was 0.27-1.04 cm3/g but that of the other active carbon, 0.23-0.62 cm3/g, was much lower than that of coconut shell active carbon. Hydrophilic adsorbent silica - gel and sepiolite showed big difference in specific surface area, but pore volumes of these were 0.47 and 0.56 cm3/g showing similar value and micropore volumes of these were, respectively, 0.06 cm3/g and 0.04 cm3/g. Total pore volume of zeolite was 0.1 cm3/g and that of micropore was only 0.02 cm3/g.