• Journal of the Korean Wood Science and Technology
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• 제39권2호
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• pp.163-171
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• 2011

Because Japanese cedar shows lower mechanical performance, glued-laminated timber (glulam) can be a better way to utilize Japanese cedar for structural purpose. However, low yield of higher grade lamination from log makes it difficult to design structural glulam. This study was aimed to increase the yield of higher grade lamination and provide higher efficiency of manufacturing structural lamination by ultrasonic log sorting technology. Logs were sorted by an existing log grading rule regulated by Korea Forest Research Institute (KFRI). It was found that the KFRI log grading rule contributed to finding better logs in viewpoint of the volumetric yield and it can reduce the number of rejected lumber by visual grading. However, it could not identify better logs to produce higher-grade products. To find an appropriate log-sorting-method for structural products, log diameter and ultrasonic time of flight (TOF) for the log were considered as factors to affect mechanical performance of resulting products. However, it was found that influence of log diameter on mechanical performance of resulting products was very small. The TOF showed a possibility to sort logs by mechanical performance of resulting products even though a coefficient of correlation was not strong (R = 0.6). In a case study, the log selection based on the ultrasonic TOF of the log increased the yield of the outermost tension lamination (E8 or better grade, KS F 3021) from 2.6% to 12.5% and reduced LTE5 (lower than E5 grade) lamination from 43.6% to 10.3%, compared with the existing KFRI log grading rule.

• 한국인터넷방송통신학회논문지
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• 제21권4호
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• pp.177-182
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• 2021

다양한 원재료를 혼합하여 원하는 성분 함유량을 가진 제품을 최소의 비용으로 생산하는 혼합 최적화 문제에 대해 일반적으로 O(n⁴)의 수행 복잡도의 선형계획법을 적용하고 있다. 본 논문에서는 이 문제에 대해 O(n log n)복잡도로 해를 얻을 수 있는 휴리스틱 알고리즘을 제안한다. 제안된 알고리즘은 합금 강판에서 요구하는 성분들의 함유량 범위를 충족시키면서 최소의 원자재비용을 얻기 위해, 원재료 단가 오름차순으로 성분별 함유량을 충족시키도록 원재료 양을 결정하였다. 3가지 사례에 대해 적용한 결과 제안된 알고리즘은 O(n log n)복잡도로 단순한 결정기법을 적용하였음에도 불구하고, LP의 최적화 기법과 동일하거나 보다 좋은 해를 얻을 수 있었다.

• Journal of Advanced Marine Engineering and Technology
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• 제7권2호
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• pp.15-21
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• 1983

Preparing for treatment and management of the emulsified fuel oil which will be generalized henceforth, this paper is an attempt to examine the viscosity-temperature characteristics of emulsified heavy fuel oil which is mixed with water and emulsifier in various mixture ratio by mechanical mixer. The experimental results are summarized as follows: 1. The viscosity-temperature characteristics of the emulsified C & B grade heavy fuel oil mixed with water of same or less weight, is changed according to log.log(v+0.6)=b-3.8log T. 2. The emulsifier has to be added to the emulsified A grade heavy fuel oil mixed with water of same or less weight, because it is instable. Especially if the emulsifier is sodium stearate, it is added more than 0.3% of the weight of oil and water. 3. In the emulsified A grade heavy fuel oil mixed with water and emulsifier, the higher the ratio of water addition becomes, the higher the viscosity is and the more the viscosity-temperature slope decreases. But the higher the ratio of emulsifier addition is, the more the viscosity-temperature slope increases. In this case, the linearity of viscosity-temperature characteristic curve is poorer than that of B and C grade heavy fuel oil. 4. In the emulsified A grade heavy fuel oil mixed with emulsifier of 0.3% or less, the emulsion type is O/W type when water addition ratio is 40%, but it is W/O type when it is 10%, 20%, 30% and 50%.

• Journal of Forest and Environmental Science
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• 제40권1호
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• pp.35-42
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• 2024

The Japanese larch (Larix kaempferi [Lamb.] Carriere) is a major timber species in Korea. However, studies on bucking rates and merchantable logs of this species are insufficient in South Korea. To bridge these gaps, in this study, the bucking rate of Japanese larch (Larix kaempferi [Lamb.] Carriere) was computed and the number of long logs and merchantable log volumes were analyzed. Sample trees were bucked according to the log grade for trading, and collected from a forest field in Gangwon Province. The bucking rate of all Japanese larch logs was >89%. The highly profitable 2-4 logs of 3.6 m length from trees with ≤30 cm diameter at breast height (DBH) and 5-6 logs with ≥34 cm DBH were produced. The bucking rate of long logs was >84%; thus, Japanese larch was found to be suitable for the supply of high-grade timber. Additionally, to follow reasonable wood supply plans, merchantable volume tables were offered based on 3.6 m-long number of logs and small-end diameter classes. Understanding the proportion of merchantable log volumes, bucking rates, and the number of long and short logs has large-scale applications in practical forestry.

• 한국IT서비스학회지
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• 제12권4호
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• pp.165-174
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• 2013

Log scaling which decides a quality grade of log is influence the price of log at the market. It is the one of important works at the field until now. So it remains using a ruler traditionally. This study evaluated the automating program through compared the automating program with using a ruler for log. The automating program used libraries of OpenCV concerning image processing algorithm to measure log diameter for scaling. In addition, it applies two panels of checkered pattern beside a pile of logs and tapes on the surface of a log diameter to find a correct value. We analyzed statistical mean difference of both log diameter and volume. In conclusion, the automating program after applying check panel and taping ins't different using a ruler. Therefore we need to considerate about applying it for improving Forest Administration.

• 한국콘텐츠학회논문지
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• 제21권10호
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• pp.1-10
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• 2021

학습관리 시스템(LMS)에 축적되는 로그 데이터는 학습 과정에 대한 양질의 정보를 제공한다. 지금까지 LMS 로그 데이터를 활용한 학업성취 예측 연구가 다양하게 수행되었지만, 상대적으로 적은 양의 학생 및 수업 데이터에 기반하고 있어 연구 결과 일반화 가능성에 한계가 존재한다. 본 연구는 대용량 LMS 로그 데이터를 이용해 대학생 학업성취를 조기예측하는 심층신경망 모델을 개발하고 성능을 검증했다. 이를 위해 가명화 처리된 LMS 로그 데이터 78,466,385건과 성적 데이터 165,846건을 활용했다. 그 결과, 본 연구에서 제안하는 예측 모델은 우수학생 집단을 학기 초부터 높은 수준의 정확도로 예측하였다. 한편 보통 및 저성취 집단에 대한 예측 정확도는 제한적인 수준이었지만, 예측시점이 늦을수록 향상되었다. 본 연구의 결과는 순수 LMS 로그 데이터만을 이용해 실제로 활용할 수 있을 정도의 일반화 성능을 가진 심층신경망 기반 조기예측 모델을 구현했다는 의의가 있다.

• 한국산림과학회지
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• 제25권1호
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• pp.49-71
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• 1975

The importance of bamboo as raw material for bamboo wares and several kinds of industrial products is highly appreciated at home and abroad. But different kinds of bamboo-bundle systems have been traditionally used in the local areas. There being no reasonable bamboo-bundle system, we have a lot of difficulty in trading bamboo products and executing adrinistmative works. Therefore, a reasonable bamboo-bundle system based on scientific proofs needs to be tested and established for fair trade and administration. This study is carried out to solve the above difficulty with statistical investigation and analysis. The results obtained are as follows. 1. The larger the circles at eye-height become, the more the possibility of the largest internode covering the span between eye-height and 1/4 height increases. 2. The longest internodes are distributed according to a rule without relation to circles at eye-height. 3. The tapering grade of bamboo culms is very high and its form is almost the same without relation to its size. (Form exponent; 0.71-1.05, eye-height form factor; 0.60-0.66, 1/4 becomes, seeing that the circle grade and the percentage of actual volume height form factor; 0.61-0.69). 4. The larger the circles at eye-height are, the lower the percentage of actual volume have negative curve relation to each other. 5. It is considered that the numbers of bamboos bundled in a "Sok" is not decided according to the usefulness of bamboos, judging from the fact that the outputs of bamboo wares per "Sok" in every circle grade are not the same. 6. As the results of the regression analysis, the empirical formulae of several amounts to circles at eye-height and culm length are as follows; Volume, $${\hat{y}}_i=\bar{3}.821874+2.013181log\;C_i+0.839128log\;H_i$$ $$V=0.0066355\;C^{2.013181}\;H^{0.839128}$$ Actual volume, $${\hat{y}}_{ai}=3.915338+0.776549log\;C_i+1.857000log\;H_i$$ $$V_a=0.0082288\;C^{0.776549}\;H^{1.857000}$$ Weight, $$w_i=3.869148+1.936410log\;C_i+0.566904log\;H_i$$ $$W=0.0073986\;G^{1.936410}\;H^{0.565904}$$ 7. Korean Phyllostachys bambusoides Sieb. et Zucc. is almost the same as that of Japan in several amounts, just the same especially in the weight. 8. It is found that the bamboo-bundle systems of Korea and Japan have much closer relation to the weight than other amounts. So It is, therefore, considered that the weight is important factor in deciding bamboo-bundle system. 9. According to the item 8, I should like to propose the appropriate numbers per "Sok" adjusted on the basis of the weight in the Table 18.

• 한국정보통신학회논문지
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• 제22권2호
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• pp.382-389
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• 2018

최근 사이버 공격은 다양한 정보시스템에 심각한 피해를 주고 있다. 로그 데이터 분석은 이러한 문제를 해결하는 하나의 방법이다. 보안 로그 분석시스템은 로그 데이터 정보를 수집, 저장, 분석하여 보안 위험에 적절히 대처할 수 있게 한다. 본 논문에서는 보안 로그 분석을 위하여 분산 검색 엔진으로 사용되고 있는 Elasticsearch와 다양한 종류의 로그 데이터를 수집하고 가공 및 처리할 수 있게 하는 Logstash를 사용하여 보안 로그 분석시스템을 설계하고 구현하였다. 분석한 로그 데이터는 Kibana를 이용하여 로그 통계 및 검색 리포트를 생성하고 그 결과를 시각화할 수 있게 하였다. 구현한 검색엔진 기반 보안 로그 분석시스템과 기존의 Flume 로그 수집기, Flume HDFS 싱크 및 HBase를 사용하여 구현한 보안 로그 분석시스템의 성능을 비교 분석하였다. 실험 결과 Elasticsearch 기반의 로그 분석시스템을 사용할 경우 하둡 기반의 로그 분석시스템에 비하여 데이터베이스 쿼리 처리시간 및 로그 데이터 분석 시간을 현저하게 줄일 수 있음을 보였다.

• Journal of the Korean Wood Science and Technology
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• 제31권6호
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• pp.22-30
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• 2003

This study was performed to obtain the basic data for high quality timber production and efficient utilization by investigating the effect of pruning on timber quality of domestic plantation-grown Korean pine (Pinus koraiensis Sieb. et Zucc.). The results were summarized as follows:Dead knots (unsound knots) in the pruned logs occurred more at upper parts when compared with in non-pruned ones. The numbers of knots on surface in heavily pruned trees were less than those in non-pruned trees, but there was no significant difference in moderately pruned trees. The required period to reveal clear timber surface without defects after pruning increased proportionally with the increase of knot diameter. The yield of clear lumber production increased by about 10% after 14 years from moderate pruning. The quality grade of log improved with more pruning practices. Knots appeared the most important factor in lowering the log grades.

• Journal of the Korean Wood Science and Technology
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• 제31권2호
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• pp.16-23
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• 2003

간벌이 국산 잣나무 조림목의 용재품질에 미치는 영향을 구명함으로써 잣나무 인공조림목의 양질재 생산과 효율적 이용을 위한 기초자료를 제공하고자 수행된 본 연구에서 다음과 같은 결과를 얻었다. 강도의 간벌을 실시한 곳에서는 원목의 단위 m당 표면옹이 출현수가 감소하였고, 죽은 옹이의 비율도 감소하였으나 옹이의 크기는 커졌으며, 옹이의 상향각은 죽은옹이가 산옹이보다 컸다. 굽은 원목은 간벌을 하지 않은 곳보다 강도간벌을 실시한 곳에서 적게 출현하였고, 원주형질률은 강도간벌을 실시한 곳에서 높게 나타났으며 지상고 3.2 m 이하 부위의 원목에서 더욱 향상되었다. 무결점재면률은 무간벌구에 비해 강도간벌구에서 향상되었으며, 원목품등은 간벌을 강하게 실시한 경우일수록 높게 나타났다.