• Journal of Biosystems Engineering
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• 제20권3호
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• pp.245-249
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• 1995

In this study power requirements to saw shoots with circular saw were determined by measuring and analyzing the required maximum torque to provide the information for the mechanization of Korean pine cone harvest. Two levels of feed rate of shoots, 10.4mm/s and 20.8mm/s, three levels of sawing speed 5.8㎧, 11.6㎧, and 17.4㎧, and 14 levels of shoot diameter from 7.7 to 18.1mm were used as variables. 1) The maximum torques were significantly affected by all three variables. The average maximum torque, 18.2 N-cm for feed rate of 20.Bmm/s was greater as much as 80% of 10.1 N-cm for feed rate of 10.4mm/s. 2) As the sawing speed was increased from 5.8㎧ to 11.6㎧ and 17.4㎧, the maximum torques were decreased to 14.8N-cm, 8.5N-cm, and 7.IN-cm, respectively when the feed rate was 10.4mm/s. The maximum torque ranged from 4.5 to 19.3N-cm as shoot diameter increased from 7.7 to 18.1mm. The minimum power requirements to saw shoots of 18.1mm with circular saw was 30W for the feed rate of 10.4mm/s. 3) The maximum torques were 28.6N-cm, 14.6N-cm, and 11.4N-cm when sawing speeds were 5.8㎧, 11.6㎧, and 17.4㎧, respectively when the feed rate was 20.8mm/s and these torques were increased as much as 93%, 36%, and 61% of those for the feed rate of 10.4mm/s. The maximum torque increased from 9.7N-cm to 30.7N-cm as shoot diameter increased from 7.7 to 18.1mm. The minimum power requirements to saw shoots of 18.1mm was 54W which was 1.8 times of 30W for the feed rate of 10.4mm/s.

• 동의생리병리학회지
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• 제16권6호
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• pp.1184-1189
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• 2002

Allii sativi Bulbus(garlic) have been shown to possess medicinal value, in particular, antimicrobial activity. In this study, we compared the efficacy on some pathogenic bacteria and fungus among several different extracts(water, hexane, ethyl acetate, methanol, chloroform) of Allii sativi Bulbus. Animal pathogenic bacteria and fungus(S. gallinarium: KCTC 2441, S. flexneri: KCTC 2361, E. cloacae: KCTC 2006, K. pneumonia: KCTC 2208, C. albicans: KCTC 1940) were used to test by measurement of minimum inhibitory concentrations(MIC) and disc diffusion. Allii sativi Bulbus were cut and mixed with water at 37℃ about 24 h and filtered, and several different solvents(hexane, chloroform, ethyl acetate, methanol) were respectively added to separate the fraction of each solvent. The antimicrobial(bacteriocidal) and antifungal effect were apparently shown from water extract, hexane and ethyl acetate extract against using strains(Staphylococcus gallinarium, Shigella flexneri, Enterobacter doacae, Klebsiella pneumonia, Candida albicans). Especially, the water extract showed the superior efficacy. And the clear zone size of water extract (11～27 mm) was greater than that of gentamycin, hexane extract and ethyl acetate extract against S. gallinarium. S. flexneri, K. pneumonia and C. albicans. Minimum inhibitory concentrations(MIC) of water extract appeared to around 2.0～7.5 ㎎/㎖ against S. gallinarium, S. flexneri, E. cloacae and K. pneumonia. The greater activity was shown by water extract because the MIC of water extract for C. albicans observed in very low concentration(<1.0 ㎎/㎖) compared to hexane(5.0 ㎎/㎖) and ethyl acetate(10.0 ㎎/㎖). Therefore, these results exhibited that water extract of Allii sativi Bulbus have stronger antimicrobial activity than hexane and ethyl acetate extract, and may be useful as topical medicine of superficial infections causing C. albicans as well as antifungal agents.

• 한국농공학회논문집
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• 제57권5호
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• pp.29-35
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• 2015

The optimal greenhouse scales for controlled tomato should be studied because the increase of oil price and labor costs following the shortage of workforce makes greenhouse cultivation hard to gain profits. The purpose of this study is to estimate optimal production scales by greenhouse types for controlled tomato. The translog cost function is estimated based on the production cost survey data. The results can be summarized as follows: First, the average production cost of controlled tomato per kg decreases as the production scale increases. Second, according to the tomatoes farm of standard farming income data of RDA, the minimum production scale is 23 ton. Third, the estimated output of single-span greenhouse considering production scale with minimum average cost is 345 ton and production cost per kg is 1,476 won. The corresponding figures of multi-span greenhouse are 415 ton and 936 won, respectively. The study results can be used as basic materials for efficient decision making of tomato farmhouses and novice farmers. Also, the study shows that multi-span greenhouse should be encouraged to be built, since it requires lower marginal cost than single greenhouse. The results of this paper will help increase the income of farmhouses and cut expenses for the coming years.

• 한국정보통신학회논문지
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• 제15권1호
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• pp.147-156
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• 2011

최근 정보시스템의 활용도가 높아짐에 따라, 많은 데이터를 이용하여 필요한 상품을 빠르게 추출하는 방법들에 대한 연구가 활발히 이루어지고 있다. 숨겨진 패턴을 탐색하는 연관 규칙 탐색 기법들이 많은 관심을 받고 있으며, Apriroi 알고리즘은 대표적인 기법이다. 그러나 Apriori 알고리즘은 반복적인 스캔으로 인한 탐색시간 증가 문제를 가지고 있다. 본 논문에서는 빈발항목의 탐색시간을 단축하기 위한 알고리즘을 제안한다. 제안한 알고리즘은 트랜잭션 데이터베이스를 이용하여 매트릭스를 생성하고 매트릭스에서 트랜잭션들의 평균 항목 개수와 정의한 최소 지지도를 사용하여 빈발 항목을 탐색한다. 트랜잭션의 평균 항목 개수는 트랜잭션의 수를 줄이는데 사용되고 최소 지지도는 항목을 줄이는데 사용된다. 제안한 알고리즘의 성능 평가는 기존 알고리즘과의 탐색시간 비교와 정확도 비교로 이루어진다. 실험 결과는 제안한 알고리즘이 기존의 Apriori와 매트릭스 알고리즘보다 최종 빈발 항목의 추출에서 빠르고 효율적으로 탐색이 이루어지는 것을 확인하였다.

• 대한치과의사협회지
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• 제55권1호
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• pp.63-70
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• 2017

Materials and methods: Sixty extracted premolars were assigned to three groups according to the root canal system (Weine's classification; type I, II and III) of 20 teeth each using radiographic examination. The root tip was cut horizontally 1 mm from the anatomical apex and the apical cross-section was visualized using microscope at x50 magnification and photographed. Minimum and maximum apical root canal diameter of each tooth was measured and classified into three types by canal morphology (round, oval and flattened shape). Statistical analysis was performed to compare the apical root canal diameter and morphology according to the root canal system. Results: In apical root canal morphology at cross-sectional view, the most common shape was round in type I, flat in type II, and oval in type III. In apical root canal diameters at cross-sectional view, there was a significant difference between the minimum and maximum diameter in all types (p<0.05). The maximum diameter was 0.331 mm in type I, 0.519 mm in type II, and 0.310 mm in type III. There was a significant difference among type I, III and type II (p<0.05). Conclusion: The morphology and diameter of apical root canal was different according to the root canal system. Therefore, clinicians should consider the apical file size in view of the apical root canal shape according to the root canal system.

• 한국조경학회지
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• 제31권1호
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• pp.66-77
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• 2003

The purpose of this study is to propose a standard putting green management program to prepare fast green suitable for international golf tournaments, and to conform whether the reported green speed model can be applied to the real field situations. The west course of Lakeside Country Club was selected for the case study. This study was initiated on August 1st, 2001 and continued through October 4th, 2001. The results are summarized as follows: 1. Following the long-term schedule, 'penncross' creeping bentgrass turf was mowed at 5.0mm(37days), 4.5mm(8days), 4.0mm(4days), 3.5mm(2days), 3.2mm(2days), 3.0mm(2days), 2.8mm(2days) and the mowing direction was changed daily. Variation of mowing height was reduced to a minimum range. Core aerification with deep tines was applied 19 days prior to the first practice round. Dry sand maintenance was top-dressed 2 times at 1.5mm/$m^2$ on the 17th day and 1.0mm/$m^2$ on the 10th day. Minimum irrigation was applied to keep the turf alive. During the tournament preparation week, dew on the putting greens was removed by using a sponge roller. Following the dew removal, the greens were cut once each morning at a height of 2.8mm. The mower used was the 21 inch working behind mower equipped with a tournament bedknife and 11 reel blades. Following the mowing, the peens were rolled with a light-weight roller in one direction in the morning. Rolling was used as a finishing technique to ensure that the surface was as smooth as possible, and to provide true ball roll and maximum green speed. In conclusion these management practices satisfied the daily green stimpmeter readings required for USGA championship play. 2. During the period of tournament preparation, no damage was observed on the green, but scalping in green edge appeared in about 0.39% of the total area of 18 greens in the west course.

• 한국터널지하공간학회 논문집
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• 제14권6호
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• pp.653-666
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• 2012

본 연구는 터널의 단면변화구간에서 발생한 손상 미케니즘에 대하여 이루어졌다. 이를 위해 단면변화 구간을 대상으로 다양한 현장조사 및 시험을 실시하였으며, 이를 바탕으로 2차원 및 3차원 수치해석을 수행하였다. 현장조사 및 시험 결과, 슬래브 손상에 대한 직접적인 원인을 찾을 수 없었으며, 2차원 수치해석을 수행한 결과 기준 안전율(1.0)을 만족하는 것으로 분석되었다. 추가로 수행한 3차원 수치해석 결과, 기둥 간격의 변화에 따라 슬래브 휨응력 변화를 전달시키지 못해 손상이 발생한 것으로 분석되었다. 보강을 위해 터널내 기둥을 추가하는 방안을 적용하였으며 그 결과, 상부 슬래브 비틀림 형상이 완화되어 보강 효과를 확인할 수 있었다. 단면 변화 구간의 경우 2차원 뿐만 아니라, 3차원으로 영향범위를 고려하여 설계에 반영한다면, 합리적이고 안정적으로 건설 및 유지관리가 가능할 것으로 판단된다. 추후에는 개착터널내 단면변화 구간에서 구조물에 영향을 최소화할 수 있는 보강방안에 대해 연구를 계속하고자 한다.

• 한국정보통신학회논문지
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• 제18권1호
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• pp.25-31
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• 2014

현재 실용화된 국내 문법 검사기는 경험적으로 구축된 오류 결정 규칙을 이용해 주위의 문맥을 보고 문법 오류를 판단하는 문맥 의존 오류를 처리하고 있다. 그러나 기존 문법 검사기의 오류 결정 규칙은 어휘 수준으로 구축되어 있어 검사기의 재현율이 낮다. 따라서 어휘대신 어휘 범주 정보를 사용하여 오류 결정 규칙을 일반화할 필요가 있다. 본 논문에서는 검사단어가 용언일 때 선택 제약 명사의 의미 범주를 국내에서 개발된 어휘의미망 KorLex에서 TCM과 MDL을 이용해 추출하고 추출된 의미 범주를 이용해 용언의 오류 결정 규칙을 일반화하는 방법을 제안한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.428-432
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• 2003

Quantitative Feedback Theory (QFT) is one of most effective methods of robust controller design and can be considered as a suitable method for systems with parametric uncertainties. Particularly it allows us to obtain controllers less conservative than other methods like $H_{\infty}$ and ${\mu}$-synthesis. In QFT method, we transform all the uncertainties and desired specifications to some boundaries in Nichols chart and then we have to find the nominal loop transfer function such that satisfies the boundaries and has the minimum high frequency gain. The major drawback of the QFT method is that there is no effective and useful method for finding this nominal loop transfer function. The usual approach to this problem involves loop-shaping in the Nichols chart by manipulating the poles and zeros of the nominal loop transfer function. This process now aided by recently developed computer aided design tools proceeds by trial and error and its success often depends heavily on the experience of the loop-shaper. Thus for the novice and First time QFT user, there is a genuine need for an automatic loop-shaping tool to generate a first-cut solution. In this paper, we approach the automatic QFT loop-shaping problem by using an algorithm involving Linear Programming (LP) techniques and Genetic Algorithm (GA).

• 화약ㆍ발파
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• 제28권1호
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• pp.40-54
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• 2010

메사쉴드공법은 주로 풍화토 또는 풍화암 구간의 소규모 굴착단면에 적용되며 대부분 인력굴착으로 이루어지나 막장면에 암반이 노출되면 유압력을 이용한 할암공법이나 발파공법의 적용이 불가피하다. 본 연구에서는 메사쉴드공법이 적용된 소규모 굴착단면 터널에서 터널상부에 상수도관 및 가스관 등이 근접되고, 강도가 높은 암반 노출로 인해 할암공법 대신에 125g의 최소장약량으로 심발공에서 초기진동을 제어하는 발파공법을 소규모 굴착단면 터널에 적용한 사례이다.