• 제목/요약/키워드: Mean Distance

검색결과 1,693건 처리시간 0.024초

경상북도 춘양지방 금강소나무림의 식생구조 및 생육밀도 (Plant Community Structure and Ecological Density of Pinus densiflora for. eracta Community in Chungyang, Kyeongsangbuk-do)

  • 이경재;김정호;한봉호
    • 한국환경생태학회지
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    • 제15권4호
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    • pp.379-393
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    • 2002
  • 본 연구는 경상북도 춘양지방 금강소나무림(이하 춘양목소나무림)의 식생구조 및 생육밀도를 밝히기 위하여 36개 조사구(단위면적: 100$m^2$)를 설치하고 식생조사를 실시하였다. 36개 조사구는 교목층의 흉고직경의 크기에 따라 군집을 분류한 결과. 군집 I (대경목), 군집 II (대경목), 군집 III(중경목), 군집 IV(소경목)의 4개 소나무군집으로 분리되었고, 교목층은 소나무, 아교목층은 쇠물푸레와 신갈나무, 관목층은 철쭉꽃과 진달래가 우점하였다. 4개 군집의 종다양도는 0.4320~0.9487(단위면적: 400$m^2$)로 낮은 상태이었으며 군집간 유사성이 높았다. 생육밀도 분석결과 흉고단면적은 평균흉고직경 이 작은 군집일수록 낮았으며, 평균흉고직경, 개체수, 최단거 리 간의 회귀분석결과 생육거리(m) = 0.0934$\times$흉고직경(cm)+0.6117, 개체수=242.47$\times$흉고직경(cm)$^{-1.1009}$, 생육거리=9.643$\times$개체수$^{-0.7016}$이었다. 아울러 본 군집들은 수령 30~50년생, 낙엽층 두께 0.5~2.5cm, 관목피도율 20% 정도로 송이생육에 적합한 것으로 판단되었다.

Intermittent Atomization Characteristics of Multi-Hole and Single-Hole Diesel Nozzle

  • Lee, Jeekuen;Kang, Shin-Jae;Park, Byungjoon
    • Journal of Mechanical Science and Technology
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    • 제16권12호
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    • pp.1693-1701
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    • 2002
  • The intermittent spray characteristics of a multi-hole and a single-hole diesel nozzle were experimentally investigated. The hole number of the multi-hole nozzle was 5, and the hole diameter of the 5-hole and the single-hole nozzle was the same as d$\_$n/=0.32 ㎜ with the constant hole length to diameter ratio(l$\_$n//d$\_$n/=2.81). The droplet diameters of the spray, including the time-resolved droplet diameter, SMD (Sauter mean diameter) and AMD (arithmetic mean diameter) , injected intermittently from the two nozzles into the still ambient were measured by using a 2-D PDPA (phase Doppler particle analyzer). Through the time-resolved evolutions of the droplet diameter, it was found that the structure of the multi-hole and the single-hole nozzle spray consisted of the three main parts : (a) the leading edge affected by surrounding air. and composed of small droplets; (b) the central part surrounded by the leading edge and mixing flow region and scarcely affected by the resistance of air, (c) the trailing edge formed by the passage of the central part. The SMD decreases gradually with the increase in the radial distance, and the constant value is obtained at the outer region of the radial distance (normalized by hole diameter) of 7-8 and 6 for the 5-hole and single-hole nozzle, respectively. The SMD along the centerline of the spray decrease shapely with the increase in the axial distance after showing the maximum value near the nozzle tip. The SMD remains the constant value near the axial distance(normalized by hole diameter) of 150 and 180 for the 5-hole and the single-hole nozzle, respectively.

한국 성인 유치악자의 상악전치 및 교합평면에 관한 연구 (A Study on the Position of the Maxillary Anterior Teeth and Orientation of Occlusal Plane in Dentulous Korean Adults)

  • 이준석
    • 구강회복응용과학지
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    • 제23권3호
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    • pp.197-203
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    • 2007
  • Statement of problem: It is very important to establish the suitable position for artificial maxillary anterior teeth and the orientation of occlusal plane in fabrication of the complete dentures. Incisive papilla has been considered the most useful anatomic landmark in the arranging of a maxillary anterior artificial teeth. Purpose: To determine correct position of upper anterior artificial teeth in complete denture patients, relationship of incisive papilla, intercanine line, occlusal plane were evaluated in Korean adults. Materials and Method: Maxillary casts were made in 60 Korean dentate subjects. Each cast was mounted in Hanau modular articulator using Hanau spring bow. Then, anatomic landmarks were determined in each cast. Distance from central incisor to incisive papilla, distance from incisive papilla to intercanine line and discrepancies between frankfurt plane and occlusal plane were measured and analysed. Results: 1. The mean distance between the posterior point of incisive papilla and the incisal edge of central incisor was 11.20 mm (in male 11.77 mm, in female 10.55 mm) and there was no significant difference in measured values between male and female 2. The mean distance between the posterior point of incisive papilla and intercanine line was 2.52 mm (Male 2.57 mm, Female 2.35 mm) and there were no significant differencies in measured values between male and female 3. The mean discripancy between the Frankfurt plane and the occlusal plane were 9. 75 degree (Male 9.81 degree, Female 9.55 degree), and there was no significant difference in measured values between left and right sides.

양손으로 물체 옮기기 과제 수행 시 우세손이 옮기는 물체의 종류와 목표점의 위치 변화가 비우세손의 팔뻗기 동작에 미치는 영향 (The Influence of Different Objects and Target Locations of Dominant Hand on the Non-Dominant Hand Movement Kinematics in Bimanual Reaching)

  • 김민희;전혜선
    • 한국전문물리치료학회지
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    • 제15권3호
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    • pp.44-52
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    • 2008
  • The purpose of this study was to investigate the effects of different objects and target location of dominant hand on the non-dominant hand movement kinematics in a bimanual reaching task. Fifteen right-handed volunteers were asked to reach from same starting point to the different target point of right and left hand with grasping the objects of different size. Independent variables were 1) three different object types (small mug cup, name pen, and PET bottle), and 2) three different target locations (shorter distance, same distance, and longer distance than the non-dominant hand) of the dominant hand. Dependent variables were movement time (MT), movement distance (MD), movement mean velocity ($MV_{mean}$), and movement peak velocity ($MV_{peak}$) of the non-dominant hand. Repeated measures two-way analysis of variance (ANOVA) was used to test for differences in the non-dominant hand movement kinematics during bimanual reaching. The results of this study were as follows: 1) MT of the non-dominant hand was increased significantly when traveling with grasping the mug cup and reaching the far target location, and was decreased significantly when traveling with grasping the PET bottle and reaching the near target location of the dominant hand. 2) MD of the non-dominant hand was significantly increased during reaching the far target location, and significantly decreased during reaching the near target location with dominant hand. 3) $MV_{mean}$ of the non-dominant hand was increased significantly when traveling with grasping the PET bottle, and was decreased significantly when traveling with grasping the mug cup of the dominant hand. Therefore, it can be concluded that the changes of the ipsilateral hand movement have influence on coupling of the contralateral hand movement in bimanual reaching.

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Evaluating the Services of the Deanship of e-Learning and Distance Education at Umm Al-Qura University According to the Opinions of Beneficiaries (Students/Faculty Members)

  • Alharthi, Ahmed;Yamani, Hanaa;Elsigini, Waleed
    • International Journal of Computer Science & Network Security
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    • 제21권9호
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    • pp.191-202
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    • 2021
  • This research was conducted with the aim to appraise the level of satisfaction of students and faculty members with the services of the Deanship of e-Learning and Distance Education at Umm Al-Qura University. In addition, it investigated any differences arising between the evaluation of students and faculty members for these services owing to their gender..To achieve these goals, a descriptive analysis methodology was used in this research. The sample comprised 1357 students (704 male and 653 female) and 372 faculty members (208 male and 164 female) from Umm Al-Qura University in the academic year 2020-2021. To collect the requisite data, the study participants were asked to complete a 5-point Likert scale questionnaire, and the validity and reliability of the data were then assessed. The findings revealed the existence of a high level of satisfaction of students and faculty members with the services of Deanship of e-Learning and Distance Education at Umm Al-Qura University. There are no statistically significant differences between the mean scores of students (male/female) at Umm Al-Qura University in evaluating the said services. Furthermore, there are no statistically significant differences between the mean scores of faculty members (male/female) at Umm Al-Qura University in evaluating these. There exist statistically significant differences between the mean scores of faculty members and students in the evaluation of the services of the Deanship for the benefit of faculty members.

레이더검지기의 차량 궤적 정보를 이용한 고속도로 공간평균속도 산출방법 비교 (Comparison of the Methodologies for Calculating Expressway Space Mean Speed Using Vehicular Trajectory Information from a Radar Detector)

  • 한음;김상범;노정현;윤일수
    • 한국ITS학회 논문지
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    • 제15권3호
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    • pp.34-44
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    • 2016
  • 본 연구에서는 고속도로 VDS에서 수집된 시간평균속도를 이용하여 공간평균속도를 산출하는 방법들의 성능을 비교하고자 한다. 이를 위해서 먼저, 이전 연구들에서 제시된 시간평균속도를 이용한 공간평균속도 추정방법들을 정리하였다. 현장에서 수집된 시간평균속도와 공간평균속도 자료는 기계 혹은 측정 상의 오차로 정확한 값을 보장하기 힘들다. 따라서 미시교통시뮬레이션모형을 이용하여 이상적인 상황에서 공간평균속도 값을 산출한 후, 본 연구에서 선정된 공간평균속도 산출방법론을 통해 산출된 추정값과 비교하였다. 비교 결과, 개별차량의 시간평균속도 자료를 이용하는 경우, 조화평균 값과 교통량-거리가중 조화평균 값이 공간평균속도 값에 가장 근사하게 분석되었다. 그리고 30초 단위 시간평균속도를 사용하는 경우에는 교통량-거리가중 조화평균 값이 가장 유사하였다. 현장에서 공간평균속도를 구하는 것이 매우 어렵기 때문에 본 연구에서는 중부고속도로에 레이더검지기를 설치하여 개별 차량의 경로자료를 수집한 후, 경로자료를 이용하여 공간평균속도를 산출하였다. 분석 결과, 교통량-거리가중 조화평균을 이용한 추정값이 공간평균속도에 비교적 유사한 것으로 나타났다.

전라남도 내의 백로류 집단번식지 특성에 관한 연구 (Study on the Characteristics of Mixed heronries in Jeollanam-do)

  • 이두표;김상진;황인천;임동옥
    • 한국환경생태학회:학술대회논문집
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    • 한국환경생태학회 2006년도 임시총회 및 학술논문발표회
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    • pp.86-96
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    • 2006
  • 본 연구는 백로류 집단번식지의 보호 및 관리에 대한 기초자료를 제공하기 위하여 2005년도 번식기에 전라남도 전역을 대상으로 번식지의 분포, 번식조류 종류 및 개체수에 대한 센서스를 실시하고 백로류 생태에 중요한 번식지 특성을 파악하였다. 센서스 결과 집단번식지는 총 17개소, 번식종류는 6종이 확인되었으며 왜가리와 중대백로가 가장 많은 지역(각각 92%)에서, 가장 많은 수(36.3%, 31.0%)가 번식하는 것으로 나타났다. 번식지 식생은 대나무 군락이 53.3%로 가장 많았다. 번식지 면적은 평균 $2,346m^2(500{\sim}7,000m^2$), 가까운 두 번식지간 거리는 평균 18.1km($5.6{\sim}40.4km$), 번식지와 마을간 거리는 평균 297m($10{\sim}2000m$), 번식지 경사도는 평균 $18^{\circ}(2^{\circ}{\sim}40^{\circ})$ 이었으며 번식지 사면방향은 동쪽이 40.0%로 가장 많았다.

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Anatomic Characteristics of Supraorbital Foramina in Korean Using Three-Dimensional Model

  • Woo, Sang Woo;Lee, Hye Joo;Nahm, Francis Sahngun;Lee, Pyung Bok;Choi, Eun Joo
    • The Korean Journal of Pain
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    • 제26권2호
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    • pp.130-134
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    • 2013
  • Background: The aims of this study were to analyze the anatomic variations of supraorbital foramina/notches in Koreans and to compare the results with those of previous studies examining other races. We evaluated the three-dimensional computed tomography (3D-CT) images of human faces using multidetector computed tomography (MDCT). Methods: A total of 395 adults (232 men and 163 women) were enrolled and the 3D-CT images of their faces were reviewed in this study. In this study, the data from the images included the presence, shape, width and distance from the nasion to the supraorbital foramina/notches. ANOVA was used to assess the main effects of gender and side (right or left foramen/notch), and comparisons of the means were done by paired t-test. Results: The most common shapes in Koreans were a single notch (39.5%) on the right hand side and a single foramen (42.3%) on the left hand side. The incidence of a single foramen in Koreans was high compared to other races. The mean foramen diameter was $2.34{\pm}0.78$ mm, and the mean distance from the nasion was $27.19{\pm}4.03$ mm. The mean notch diameter was $3.37{\pm}1.71$ mm, and the mean distance from the nasion was $23.42{\pm}2.45$ mm. Conclusions: This is the first study on the variations of supraorbital foramina/notches in Koreans using 3D-CT images of faces. The anatomic characteristics of the supraorbital foramina/notch will help in performing nerve blocks and maxillofacial surgery.

접번축(蝶番軸) 위치(位置) 결정시(決定時)의 정밀성(精密性)에 대(對)한 연구(硏究) (A Study on Accuracy in Determining the Hinge Axis Location)

  • 김춘호;계기성
    • 대한치과보철학회지
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    • 제24권1호
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    • pp.17-26
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    • 1986
  • The purpose of this study was to investigate true hinge axis location with different times (8:00-9:00 A.M.,2:00-3:00 P.M.) and with experienced and inexperienced groups. 25 subjects, 23-27 years of age , with functionally acceptable occlusion, and no clinical signs of temporomandibular joint dysfunction were participated in this study. In this study arbitrary hinge axis point was located 13 mm anterior to the posterior margin of the tragus on a line from the center of the tragus to the outer canthus of the eye and then the true hinge axis point was located with T.M.J. hinge axis locator. The discrepancies of distance and the direction between true hinge axis point and arbitrary hinge axis point were studied according to times and two groups. The results obtained were as follows : 1. The mean distance from arbitrary hinge axis point to the true hinge axis point on the right and left sides was as follows : Experienced group: linear distance: $1.228{\pm}3.145mm$, vertical distance: $-1.128{\pm}2.515mm$, horizontal distance: $-0.484{\pm}1.806mm$. Inexperience group: linear distance: $1.628{\pm}3.158mm$, vertical distance: $-1.169{\pm}2.090mm$, horizontal distance: $-1.133{\pm}2.367mm$. Horizontal distance between experienced and inexperienced groups was significant statistically. (P<0.1) 2. True hinge axis points located within 5 mm of arbitrary hinge axis point were 86.7% in the experienced group and 84% in the inexperienced group. 3. For experienced operator A with time, the mean distance from arbitrary hinge axis point to true hinge axis point was as follows: Horizontal distance: AM: $-0.613{\pm}1.966mm$, PM: $-0.860{\pm}2.156mm$. Vertical distance: AM: $-0.886{\pm}2.518mm$, PM : $-1.226{\pm}2.660mm$. True hinge axis points had tendency to be located posterior-inferiorly to tragus-canthus line in the afternoon than in the morning, but there was not significant statistically. (P>0.1)

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콘빔형 전산화단층영상을 이용한 한국인의 본윌 삼각에 대한 평가 (Evaluation of Bonwill triangle using cone beam computerized tomography in Korean)

  • 공현준;오상천
    • 구강회복응용과학지
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    • 제34권2호
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    • pp.97-103
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    • 2018
  • 목적: 본 연구의 목적은 콘빔형 전산화단층영상(cone-beam computerized tomography)을 이용하여 한국인의 본윌 삼각을 평가함으로써 그간 서양인을 기준으로 제시된 본윌 삼각 관련 수치와 비교하기 위함이다. 연구 재료 및 방법: 원광대학교 치과대학 대전치과병원에 내원하여 Cone-beam CT를 촬영한 환자 중, 본 연구의 기준에 적합한 한국인 120명(남성 60명, 여성 60명)이 선택되었으며 Invivo 5.1 (Anatomage, San Jose, USA)가 Cone-beam CT scan을 분석하기 위해 사용되었다. 축의 방향설정을 시행한 후, 과두간 거리는 각 과두의 중심점을 지정하여 측정하였으며, 과두-절치간 거리는 과두 중심점과 하악 양 중절치 절단연의 접촉점을 지정하여 측정하였다. 수집된 자료는 SPSS Version 23.0 (IBM Inc., Armonk, USA)을 이용하여 분석하였고, independent t-test를 이용하여 성별에 따른 통계적 유의성을 검증하였다. 결과: 한국인의 평균 과두간 거리는 105.9 mm였으며, 남성(108.3 mm)이 여성(103.4 mm)에 비해 통계학적으로 유의하게 크게 나타났다. 한국인의 평균 과두-절치간 거리는 105.2 mm였으며, 남성(108.1 mm)이 여성(102.3 mm)에 비해 통계학적으로 유의하게 크게 나타났다. 결론: 본 연구에서 측정된 한국인의 과두간 거리는 105.9 mm로 서양인을 대상으로 제시된 110 mm에 비해 작은 값을 보였으며, 남성이 여성에 비해 통계학적으로 유의하게 크게 나타났다. 본 제한된 연구 결과를 근거로 한국인의 보철적 수복 시 과두간 거리를 좀 더 개인에 맞게 조절할 수 있는 교합기 사용이 필요하다고 사료된다.