• 전산구조공학
• /
• 제11권1호
• /
• pp.251-259
• /
• 1998

개구부를 갖는 콘크리트 전단벽을 두께가 얇은 직사각형 평판으로 모델화하였다. 판의 두가지 경계조건에 대한 안정해석 결과를 판좌굴계수 k로 표시하였다. 경계조건이 다른 변수로는 휨으로 인한 힘/연직하중비 .alpha., 수평 전단력/연직하중비 .betha. 및 개구부의 위치 및 크기 변화이다. 유한요소법에 의한 결과를 얻기 위하여 예제의 판을 27*9의 정사각형 요소로 분할하였으며 node에서 3가지 자유도를 갖는 c.deg. 유한요소를 택하였다. 일반적으로 개구부의 크기가 증가함에 따라 판 개구부가 판 중앙에서 자유연(free edge)으로 접근할수록 좌굴계수는 감소하는 현상을 보이고 있다.

• 한국조경학회지
• /
• 제28권3호
• /
• pp.88-96
• /
• 2000

The objective of this study is to evaluate the preference and visual characteristic of users according to the location of benches at urban community parks. The types of benches are separated into four patterns and located in four representative places at urban community parks. Each relations between visual preference and adjective related factors are calibrated by the estimated results of Pearson correlation coefficient. Moreover, the factors which affect the visual preference are obtained by multiple regression analysis and to calibrate the each factors significant level, the method of multivariate variance analysis is applied. The results of this study are summzrized as belows: 1. Four types of factors which consist the visual characteristic are classified as emotional factor of visual images(aesthetic factor(F1), texture related factor(F2)) and physical factor(physical factor(F3), transformable factor(F4)). Each factor's eigenvalue is appears as 5.27∼1.78 and the eigenvalue of emotional factor of visual images is more higher than the physical factor. 2. The correlation coefficient between visual preference according to the location of benches(X21) and aesthetic factor(f1) is estimated as 0.79, which is highest value among the four factors. And the correlation coefficient of texture related factor(f2), physical factor(F3) and transformable factor(F4) is estimated as 0.14, 0.04 and 0.08 respectively. 3. The visual preference of users according to the location of benches is greatly affected by the emotional factor of visual images(F1, F2) and the physical factor(F3, F4) are poorly related. The results of this study suggest the effective guidelines for the location of leisure facilities. Moreover the design and planning of leisure facilities at the urban community park have to be reexamined. What must be examined from now on is as follows: First, the preference research of rest facilities in the urban park through the multiple approach must be carried out continuously. Second, the research about the visual quality of the environmental sight observed in sitting on the bench as well as the visual quality of the showed object and place needs to be supported. Nevertheless, through this study the utilization into the useful data of the plan and the design for the systematic disposition of landscape architecture equipments centered on the users can be expected.

• 한국농공학회지
• /
• 제31권2호
• /
• pp.104-115
• /
• 1989

In an effort to clarify the wetted patterns of sandy loam soil under trickle irrigation conditions, the distance of wetted zone, infiltration capacity and soil wetted patterns, etc. were measured by gypsum block as soil moisture sensor located every 5 cm vertically and horizontaly in the soil bin under the such conditions as a). irrigation rates set to 2, 4, 6, 8 liters per hour b). total amount of water applied fixed to 14.62 liters per soil bin c) the hearing force of soil measured by plate penetrometer ranging from 1.04 to 1.22kg/cm$_2$ The results can be summarized as follows ; 1. The wetted distance in horizontal direction(H), the wetted distance in vertical direction(D), the horizontal infiltration capacity (iH) and the vertical infiltration capacity(in)could by explained as a function of time t. 2. The horizontal wetted distance (H) is explained by an exponetial function H= a$.$ t where b was found ranging from 021 to 026 under surface trickle irrigation, which was considered a lotlower than the classical value of 0.5 and these measurements were indifferent to the increasing irrigation rates. 3. As for the surface trickle irrigation where horizontal infiltration capacity(iH) is explained as iH = A $.$ t h, the coefficient A increases with respect to irrigation rates within the limits of 0.89~1.34. 4. In terms of surface trickle irrigation of the ratio of Dm Which is maximum vertical wetted distance to Hm, which is maximum horizontal wetted distance, found to be within range of 1.0 to 1.21. It was also noted that the value of Dm decreses when irrigation rates increases while the value of Hm changes the opposite direction. 5. The optimum location of sensors from emitter for surface trickle irrigation should he inside of hemisphere whose lateral radius is 28~30cm long and vertical radius is 10~12cm long. The distance between emitters should be within 60cm long. 6. In the study of vertical wetted distance( D) where D= a $.$ tb, the exponential coefficient b ranged from 0.61 to 0.75 in surface trickle irrigation, and from 0A9 to 0.68 for subsurface trickle irrigation. These measurements showed an increasing tendency to with respect to irrigation rates. 7. In case of vertical infiltration capacity( in), where iD= A $.$ t 1-h, the coefficient A for surface trickle irrigation found to be within range of 0.16 to 0.19 and did not show any relationships with varying degree of irrigation rates. However, the coefficient was varying from 0.09 to 0.22 and showed a tendency to increase vis-a-vis irrigation rates for subsurface trickle irrigation, in contrast. 8. In the observation of subsurface trickle irrigation, it was found that Dm/Hm ratio was within 1.52 to 1.91 and showed a decreasing tendency with respect to increasing rates of irrigation. 9. The location of sensors for subsurface trickle irrigation follows same pattern as above, with vertical distance from emitter being 10~17cm long and horizontal 22~25cm long. The location of emitter should be 50 cm. 10.The relationship between VS which is the volume of wetted soil and Q which is the total amount of water when soil is reached field capacity could be explained as VS= 2.914Q0.91and the irrigation rates showed no impacts on the above relationship.

• 한국측량학회지
• /
• 제40권3호
• /
• pp.159-168
• /
• 2022

지방자치단체는 생활SOC의 불균형을 해소하려는 노력을 추진되어야 하며, 생활SOC의 입지 현황, 최적입지 등에 관한 공간정보를 구축해야 한다. 이 연구는 생활SOC 관련 연구수요를 고려하여, 생활SOC의 접근성, 형평성, 그리고 최적입지를 분석하였다. 분석 시설은 생활거점시설로서, 공공도서관, 근린공원, 생활문화센터, 국공립어린이집으로 구성하였다. 분석지역은 경기도 수원시이며, 분석의 기준연도는 2020년이다. 접근성은 세생활권(200m×200m)에서 인구 1인당 접근성을 산출하였다. 형평성은 지니계수를 활용하여 동 간 접근성의 지역 간 격차를 확인하였다. 최적입지는 최대 커버링 입지문제를 활용하여 탐색하였다. 분석 결과, 국공립어린이집을 제외한 시설의 공간적 접근성은 지역 간 커다란 차이를 드러냈다. 접근성이 우수한 지역도 시설에 따라 커다란 편차를 보였다. 생활SOC의 지역 간 격차는 생활문화센터가 가장 컸으며, 뒤를 이어, 근린공원, 국공립어린이집, 공공도서관 순으로 나타났다. 공공도서관, 근린공원, 생활문화센터의 최적입지는 원도심에 집중적으로 분포하였으나, 국공립어린이집의 최적입지는 수원시 전역에서 나타났다. 이 연구의 결과는 추후 지방자치단체에서 생활SOC 공급계획을 수립함에 있어 핵심적인 계획내용이다. 따라서 후속연구는 이 연구의 분석구조와 결과를 유용하게 활용 가능할 것으로 기대한다.

• 대한기계학회논문집A
• /
• 제24권10호
• /
• pp.2487-2495
• /
• 2000

The acoustic characteristics of expansion chamber will be changed with the variation of inlet/outlet location due to the higher order acoustic mode in a high frequency in which the plane wave theory is not available. In this paper, the acoustic performance of reactive type expansion chamber with circular cross-section is analyzed by using the modified mode matching theory. The sensitivity analysis of four-pole parameters with respect to the location of inlet and outlet is also suggested to increase the acoustic performance. The acoustic power transmission coefficient is used as cost function, and the location of inlet and outlet is used as design variables. The steepest descent method and SUMT algorithm are used for optimization technique. Several results showed that the expansion chamber with optimally located inlet/outlet had better acoustic performance than concentric expansion chamber.

• 대한조선학회논문집
• /
• 제58권5호
• /
• pp.330-338
• /
• 2021

This paper focuses on the improvement of the influence coefficient matrix method for estimation of local ice load on the icebreaking research vessel ARAON. The influence coefficient matrix relates ice pressure on the hull plate to the measured/calculated hull strain/stress. Conventionally von Mises equivalent stresses representing hull stresses and ice pressure acting on the hull plate are utilized to assemble the influence coefficient matrix. Because of the three dimensional features of the ship-ice collision process, an enhanced method to assemble the influence coefficient matrix is derived considering ice loads in the X, Y, and Z direction simultaneously. Furthermore the location of ice loads acting on hull-plate may fall outside the measuring sensor area, and the enhanced influence coefficient matrix is modified to reduce the difference between the actual and the estimated ice loads by expanding the domain outward from the sensor area. The developed method for enhanced influence coefficient matrix is applied to IBRV ARAON during the 2019 Antarctic ice field test and the local ice loads in three directions are efficiently calculated compared to those by a conventional method.

• Wind and Structures
• /
• 제37권6호
• /
• pp.425-444
• /
• 2023

This study is to investigate the effect of interference between two C-shaped high-rise buildings by computational fluid dynamics (CFD), focusing on the variation of the local pressure coefficient (C_P) and the mean pressure coefficient (C_PMEAN). Sixteen building position cases are considered for the present study. These cases were based on the position and height of the interference building (IB). The pressure coefficient (C_P) is calculated on the principal building (PB) and is compared with an isolated building identical in shape and size. The interference effect on PB has also been presented in reference for the interference factor (IF). According to the findings, the maximum force coefficient on the PB is 0.971 and it is 10.97% more than the isolated PB when IB is located at position 2b (two times the width of the building), and the interfering height of 13H/15 mm. The moment coefficient on PB is 1.27, which is 27.36% less than the isolated case in which IB pushed 2b to 3b in the y direction with 750 mm height. In most of the cases, because of the shielding effect of the IB, the value of force coefficient (C_F) on PB has been reduced. On the face of the PB, there are also considerable differences in the mean pressure coefficient C_PMEAN. When IB was positioned at a location of 2b in Y direction and an interfering height of 13H/15 mm, the maximum C_PMEAN (1.58) was observed on the leeward face of PB.

• 대한전자공학회논문지SD
• /
• 제47권6호
• /
• pp.43-50
• /
• 2010

본 논문에서는 시스템 모듈에서 발생하는 EMI를 줄이기 위해 분할된 전원/접지 평판 구조에 의해 발생하는 방사성 방출(Radiated emission)을 분석하였다. 분석을 위해 다양한 조건을 갖는 시험 기판(Test board)에 대한 자기장과 전기장을 시뮬레이션하고 측정하여 비교하였다. 이 분석 결과는 입력 신호의 주파수 대역에서 반사계수의 위상이 $0^{\circ}$에 근접하도록 하며, 입력 신호의 주파수와 분할된 전원/접지 평판 구조의 공진주파수가 일치하지 않도록 분할된 접지 갭의 폭과 위치를 결정함으로써 방사성 방출을 줄일 수 있음을 보여준다. 또한, 스티칭 커패시터(Stitching capacitor)를 사용하여 방사성 방출을 저감시킬 수 있으며, 방사성 방출을 효과적으로 저감시키기 위해 입력 신호의 주파수에서 반사계수의 크기를 낮추고 위상이 $0^{\circ}$에 근접하도록 스티칭 커패시터의 값과 위치를 결정할 필요가 있음을 알 수 있다.

• 대한토목학회논문집
• /
• 제13권5호
• /
• pp.173-181
• /
• 1993

자연하천에 대한 합리적인 하천개수계획수립 및 유로의 유지관리면에서 반드시 규명되어야 할 유로만곡부에서의 정량적인 해석은 여러가지 접근방법이 있으며, 사행하천의 유로이동에 대한 예측은 도로, 교량 등의 위치선정과 기존하천구조물의 방재에 필수적이다. 하상계수가 큰 우리나라의 하천에 유로이동 예측모형을 적용할 때 유량은 기간별-지배유량을 고려하는 것이 타당할 것으로 사료되며, 본 연구대상 유역에 대한 침식계수, 유로이동에 대한 평균오차량, 하상세굴계수 등을 비교검토한 결과 유로이동을 지배하는 유량이 존재함을 알 수 있으며, 연구대상유역에서 유로이동에 대한 지배유량은 재현기간 4년에 해당하는 6,000CMS 이상으로 사료된다. 유로이동모형을 실측값이 있는 남한강의 연구대상유로에 적용하여 침식계수를 구하였으며, 계산된 침식계수를 이용하여 그 유로에서의 2000년에 대한 유로이동을 예측하였다.

• Clinics in Shoulder and Elbow
• /
• 제21권4호
• /
• pp.200-206
• /
• 2018

Background: The purpose of this study was to assess the relevance of preoperative magnetic resonance imaging (MRI) evaluation by occupation ratio (OR) at maximum diameter of supraspinatus muscle. Methods: Patients from the Inje University Sanggye Paik Hospital who received rotator cuff repair and underwent pre- and postoperative MRI were selected as subjects of this study. On T1-weighted MRIs, OR of fat and muscle at Y-shaped view, OR at a location on supraspinatus muscle where its diameter was maximum on coronal view, and pre- and postoperative Goutallier Classification and changes in the tangent sign were measured. Statistical significance of postoperative OR was assessed regarding time from symptom onset to surgery, size of rotator cuff tear, preoperative OR, and the difference between ORs measured at maximum diameter of supraspinatus muscle and Y-shaped view. Results: Preoperative OR at Y-shaped view was $52.28{\pm}8.57$ (32.5-65.3). Preoperative OR difference between maximum diameter and Y-shaped view was $13.76{\pm}10.51$ (2.38-42.04), and Pearson correlation coefficient was 0.604 (p=0.001). Postoperative OR at Y-shaped view was $63.77{\pm}9.35$ (37.3-76.1). Pearson correlation coefficient of pre- and postoperative Goutallier Classification was -0.579 (p=0.002) and Pearson correlation coefficient of the postoperative difference between ORs measured at maximum diameter of supraspinatus muscle and Y-shaped view was -0.386 (p=0.047). Conclusions: Fatty degeneration of supraspinatus muscle in rotator cuff tear patients should be evaluated not only in the conventional Y-shaped view, but also at location of maximum diameter of supraspinatus muscle to establish patients' therapeutic plan.