• 한국공간구조학회논문집
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• 제7권5호
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• pp.83-87
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• 2007

비대칭 및 대칭 변단면 압축재( = m)의 임계하중을 수치 해석법의 하나인 유한 요소법으로 결정하였다. 해석에서 고려한 변수는 taper parameter(=a) 와 단면 성능 변수 m이다. 구조설계 및 구조의 안전 검토에 임하는 구조 기술자들의 편의를 위하여 유한요소법으로 결정한 임계하중의 계수 변화는 하나의 대수식으로 표시하였다. 대수식에 나타나는 계수들은 회귀분석법으로 결정하였다.

• 농업생명과학연구
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• 제44권4호
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• pp.1-7
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• 2010

본 연구는 난대산림연구소의 제주시험림에 있는 서어나무 (Carpinus laxiflora)에 대한 개체목의 수간곡선식 추정 및 재적표를 개발하기 위하여 수행하였다. 최적의 추정식을 선택하기 위하여 Max & Burkhart식, Kozak식 및 Lee식을 적용하여 수간곡선식을 유도한 후, 각 식의 직경 추정에 대한 검정 통계량 및 실측치와 추정치간의 오차분포를 검증하였다. 그 결과 Max & Burkhart식 및 Lee식이 특정 구간에서 과대치 또는 과소 추정치를 보인데 반하여 Kozak식은 전구간에서 고른 분포를 보였다. 추정력이 가장 좋은 Kozak식을 활용하여 수피포함 재적표를 작성하였다.

• 한국소음진동공학회논문집
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• 제23권4호
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• pp.338-346
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• 2013

Equations of motion of a rotating blade considering pre-twist angle, cross section taper and a concentrated mass are derived using the hybrid deformation variable modeling method. For the modeling of a concentrated mass which is located at an arbitrary position of the blade, a Dirac delta function is employed for the mass density function. The final equations for the vibration analysis are transformed into a dimensionless form using several dimensionless parameters. The effects of the dimensionless parameters on the vibration characteristics of the rotating blade are investigated through numerical analysis.

• The Korean Journal of Ecology
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• 제26권3호
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• pp.123-127
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• 2003

Cubic-meter volumes estimated from two proxy taper functions were compared to observed volumes of Japanese red cedar trees (Cryptomeria japonica D. Don) to evaluate accuracy and precision in the centroid method. Centroid volume estimates were also compared to volume estimates from existing whole-tree volume equations developed for another geographic region. This study found that one proxy function produced unbiased volume estimates while the other was biased. Volume estimates from the whole-tree equations were also biased. However, the volume estimates from the whole-tree equations were more precise than those from the centroid method. These results support previous studies that the centroid method can produce reliable volumes of trees when no other reliable volume equations exist.

• 한국산림과학회지
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• 제99권1호
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• pp.57-61
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• 2010

본 연구는 난대산림연구소의 제주시험림에 있는 붉가시나무(Quercus acuta)에 대한 개체목의 수간곡선식 추정 및 간재적을 추정하기 위하여 수행되었다. 최적의 추정식을 선택하기 위하여 Max and Burkhart식, Kozak식 및 Lee식을 적용하여 각 식의 직경 추정에 대한 검정 통계량 및 실측치와 추정치간의 오차분포를 검증하였다. 그 결과 Max and Burkhart식 및 Lee식이 특정 구간에서 과대치 또는 과소 추정치를 보인데 반하여 Kozak식은 전구간에서 고른 분포를 보였다. 추정력이 가장 좋은 Kozak식을 활용하여 수피포함 재적표를 작성하였다.

• 한국산림과학회지
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• 제83권1호
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• pp.63-74
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• 1994

단목(單木) 또는 임분(林分)의 생장파악 및 예측을 위해서는 수간형태(樹幹形態)의 파악이 선행되어야 한다. 또한 임분의 생장을 동적(動的)으로 파악하기 위해서는 수간형태(樹幹形態)를 수식화(數式化)할 필요가 있다. 그러나 수간(樹幹)은 전체적으로는 원추형(圓錐型)에 가깝지만 그 가늘어지는 정도가 부분적으로 다르기 때문에 하나의 식(式)으로 표현하기엔 어려움이 있으므로, 부분적으로 상이한 계수를 갖는 구간추정식(區間推定式)으로 표현하는 것이 이상적이다. 본 논문에서는 spline함수로부터 유도된 단목간곡선의 집합으로부터, 선형관계식을 이용하여 임분간곡선(林分幹曲線)을 수식화하는 방법을 소개하였다. 이와 같이 수간형태(樹幹形態)를 수식화(數式化) 한 단목 및 임분의 간곡선식(幹曲線式)은 임분(林分)의 발달과정을 동적(動的)으로 파악할 수 있게 하여 임분생장연구의 다양성 및 합리적 산림계획모델의 기초를 제공한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.990-994
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• 2004

This paper presents a method to predict the transient characteristic of the air lubricated slider head in a hard disk drive by using optimization technique. The time dependent modified Reynolds equation based on the molecular slip flow approximation equations was used to describe the fluid flow within the air bearing and the implicit finite difference scheme is applied to calculate the pressure distribution under the slider head. The exhaustive search combined with the Broyden-Fletcher-Goldfarb-Shanno method were employed to obtain optimum design variables which are taper angle, rail width and taper length in order to keep the forces and moments acting on the slider head in dynamic equilibrium. The results show that the optimal head slider of the magnetic head has good stability characteristic that can reach the steady state within 0.5 microsecond.

• 농업생명과학연구
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• 제43권1호
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• pp.17-23
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• 2009

This study was conducted to compare volumes estimated from two taper functions and observed volumes of Chamaecyparis obtusa trees to evaluate accuracy and precision of centroid method. Centroid volume estimates were also compared with volume estimates from existing Forest Resources Evaluation and Prediction Program. The results of this study showed that Gregoire's simple taper function produced unbiased volume estimates while the others were biased. Volume estimates from the Forest Resources Evaluation and Prediction Program were also biased when applied in the Jangseong National Forest regions. These results suggested that the centroid method could produce reliable stem volumes of trees when no other reliable stem volume equations exist.

• International Journal of Control, Automation, and Systems
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• 제5권4호
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• pp.419-428
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• 2007

This paper describes the development of a six-axis force/moment sensor with rectangular taper beams for an intelligent robot's wrist and ankle. In order to accurately push and pull an object with an intelligent robot's hand, and in order to safely walk with an intelligent robot's foot, the robot's wrist and ankle should measure three forces Fx, Fy, and Fz, and three moments Mx, My, and Mz simultaneously from the mounted six-axis force/moment sensor to the intelligent robot's wrist and ankle. Unfortunately, the developed six-axis force/moment sensor utilized in other industrial fields is not proper for an intelligent robot's wrist and ankle in the size and the rated output of the six-axis force/moment sensor. In this paper, the structure of a six-axis force/moment sensor with rectangular taper beams was newly modeled for an intelligent robot's wrist and ankle, and the sensing elements were designed by using the derived equations, following which the six-axis force/moment sensor was fabricated by attaching strain-gages on the sensing elements. Moreover, the characteristic test of the developed sensor was carried out by using the six-component force/moment sensor testing machine. The rated outputs from the derived equations agree well with those from the experiments. The interference error of the sensor is less than 2.87%.

• Journal of Forest and Environmental Science
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• 제33권4호
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• pp.315-321
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• 2017

This study was carried out to estimate the parameters of stem taper functions, to figure out the best taper model by species, and to compare with previous studies by species, targeting on the stemmed tree samples collected from the Korean red pine (Pinus densiflora), Korean white pine (Pinus koraiensis), and Japanese larch (Larix kaempferi ) stands in Gangwon and North Gyeongsang provinces of South Korea. The seven widely used models were applied in this study, and Muhairwe 1999 model for Korean red pine and Korean white pine and Kozak 2002 model for Japanese larch were evaluated as the best model for each species according to the fit statistics and the predicted stem form comparison. In addition, the predicted diameter was suitably fitted when comparing the previous studies, and the values were more appropriate following stem taper according to neiloid, paraboloid, and cone parts by species. Consequently, the estimation of this study was considered to represent the stem taper well. When comparing stem taper of three species, the diameter was largest in Korean white pine. Overall, the taper models of this study are judged to be useful for estimating stem form and volume computation of Korean red pine, Korean white pine, and Japanese larch.