• Title/Summary/Keyword: j1962

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Computation of Wave Resistance in the Water of Finite Depth Using a Panel Method (패널법을 이용한 유한수심에서의 조파저항 계산)

  • S.J. Lee
    • Journal of the Society of Naval Architects of Korea
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    • v.29 no.4
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    • pp.66-74
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    • 1992
  • A panel method in the spirit of Hess & Smith(1962), and also of Dawson(1977) was developed to compute the wave resistance of a submerged, or a surface piercing, body moving in the water of finite depth. As a boundary condition on the free surface what is called the Poisson equation is used, while Yasukawa(1989) chose the Dawson equation for which the double-body flow is regarded as the basic one. In order to satisfy the boundary condition on the bottom surface automatically, the sum of a Rankine source and its image with respect to the bottom surface is chosen as the Green function, and hence the singularity is distributed only on the body and on the free surface thereby decreasing the required number of panels dramatically, compared to that of Yasukawa, without the consequential loss of accuracy. Calculations were done for a submerged sphere and for the Wigley hull, and the results are compared with other existing analytical and numerical data.

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Seismic vulnerability of old confined masonry buildings in Osijek, Croatia

  • Hadzima-Nyarko, Marijana;Pavica, Gordana;Lesic, Marija
    • Earthquakes and Structures
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    • v.11 no.4
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    • pp.629-648
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    • 2016
  • This paper deals with 111 buildings built between 1962 and 1987, from various parts of the city of Osijek, for which, through the collection of documentation, a database is created. The aim of this paper is to provide the first steps in assessing seismic risk in Osijek applying method based on vulnerability index. This index uses collected information of parameters of the building: the structural system, the construction year, plan, the height, i.e., the number of stories, the type of foundation, the structural and non-structural elements, the type and the quality of main construction material, the position in the block and built-up area. According to this method defining five damage states, the action is expressed in terms of the macroseismic intensity and the seismic quality of the buildings by means of a vulnerability index. The value of the vulnerability index can be changed depending on the structural systems, quality of construction, etc., by introducing behavior and regional modifiers based on expert judgments. Since there is no available data of damaged buildings under earthquake loading in our country, we will propose behavior modifiers based on values suggested by earlier works and on judgment based on available project documentation of the considered buildings. Depending on the proposed modifiers, the seismic vulnerability of existing buildings in the city of Osijek will be assessed. The resulting vulnerability of the considered residential buildings provides necessary insight for emergency planning and for identification of critical objects vulnerable to seismic loading.

A Case of Oligomeganephronia of the Solitary Kidney, Presented with Isolated Proteinuria (단독 단백뇨로 발현된 단일신의 oligomeganephronia 1례)

  • Park Soeun;Lee Jung Won;Cho Su Jin;Yoo Eun Sun;Kim Hae Soon;Sung Soon Hee;Lee Seung Joo
    • Childhood Kidney Diseases
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    • v.6 no.1
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    • pp.92-96
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    • 2002
  • Oligomeganephronia is rare congenital anomaly characterized by striking reduction of the number of nephrons, which are markedly hypertrophied in renal hypoplasia. Since the first description of oligomeganephronia in bilateral renal hypoplasia in 1962, dozens of cases were reported. Van Acker reported the first case of oligomeganephronia developed in the solitary kidney and 8 cases were searched in the literature. We report a case of oligomeganephronia in the solitary kidney in 13 years old boy, presented with isolated proteinuria as a first case in Korea. (J Korean Soc Pediatr Nephrol 2002 ; 6:92-6)

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Simulation and evaluation of fiber optics for hand-piece using ray tracing method (광선추적법을 이용한 핸드피스용 광섬유 광학계 시뮬레이션 및 특성 평가)

  • Park, J.H.;Kim, H.;Yang, B.C.;Lee, B.H.;Yoo, Y.J.;Kim, D.W.;Lee, C.W.;Lee, C.W.
    • Proceedings of the KIEE Conference
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    • 2002.07c
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    • pp.1962-1963
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    • 2002
  • The hand-piece fiber optics is applied to medical appliances such as glaucoma theraphy to focus semiconductor laser on the affected parts efficiently. In this paper, we evaluate optical properties such as beam power and radius of a hand-piece probe by experiments and we also simulate the hand-piece optics by ray tracing method in order to study major parameters to optimize focalization ability. As results, we show experimental and simulation results of the hand-piece optics and also summarize several requirements that have to be considered in optimizing the hand-piece optics.

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Integrated OBD-II connector for reading vehicle driving information (자동차 주행 정보를 읽기 위한 통합 OBD-II 커넥터 구현)

  • Baek, Sung-hyun;Jang, Jong-Wook
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2013.05a
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    • pp.307-310
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    • 2013
  • 최근 스마트폰, 블랙박스, EDR등에서 자동차 네트워크인 OBD-II를 이용하여 자동차 실시간 제어데이터를 알 수 있게 되었다. 하지만 각각의 장치(스마트폰, 블랙박스, EDR등)에서는 OBD-II에서 자동차 데이터를 수신 받을 때 사용되는 통신 네트워크가 다르다. 본 논문은 이러한 단점을 보완 하고자 각 장치에서 대부분 사용되어 지는 Bluetooth와 Wifi, WCDMA 모듈을 통합하여 사용자가 1개의 리더기 만으로도 어느 장치에서든지 OBD-II네트워크에서 자동차 실시간 제어 데이터를 알 수 있는 OBD-II 네트워크의 리더를 위한 통합 하드웨어를 구현 하였다.

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A Study on the Determinants of Physical Distribution Costs in Korea (한국경제물류비용의 결정요인에 관한 연구)

  • 김관영;주만수
    • Journal of the Korean Regional Science Association
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    • v.14 no.1
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    • pp.1-20
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    • 1998
  • In this paper, the authors studied a comprehensive study of national physical distribution costs used here was originally developed by J. L. Heskett(1962) and modified in Korean context by Oh-Kyung Kwon(1997). Using this method the authors calculated national physical distribution costs in Korea from 1984 to 1996. Unlke the major industrialized countries, national physical distribution costs in Korea showed continuous increasing trend in every senses. Using this time series data on physical distribution costs, we analysis the inefficiencies in the physical distribution and figured out the sources of these inefficiencies. The major sources of increasing physical distribution costs in Korea were (1) increasing traffic congestion measured by number of automobiles per road-kilometer, (2) increasing real wages, and (3) high interest rates. Especially, alternatives adopted by firms facing increasing traffic congestion were buying more vehicles, which in turn caused more serious congestion ever. This inefficient cycle in physical distribution area should be cut somehow in order to restore national competitiveness of Korean frims by reducing physical distributins costs.

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Infiltration and Percolation Characteristics of Water in Agricultural Land Filled with Rock-Dust (암분 매립 농경지 토양의 표면 침투 및 삼투 특성)

  • Hur, S.O.;Jeon, S.H.;Lee, Y.J.;Han, K.H.;Jo, H.R.;Kang, S.S.;Kim, M.S.;Ha, S.G.;Kim, J.G.
    • Korean Journal of Soil Science and Fertilizer
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    • v.42 no.spc
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    • pp.40-44
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    • 2009
  • This study was carried for the understanding of infiltration and percolation characteristics of water in agricultural land filled with rock-dust (Technosols). The experiment was performed at two sites (A, B), and soil horizons of the sites were classified with 4 layers, respectively. The soil texture of all soil horizons was analyzed with silt loam (SiL) except for the soil texture, which was loamy sand (LS), at the lowest horizon of measurement site A. The bulk densities at each horizon of two soils were mostly over $1.49g{\cdot}cm^{-3}$, which is very higher than $1.25g{\cdot}cm^{-3}$ of typical medium-textured mineral soil, except for the surface of site A measured immediately after tillage. The concentrations of $P_2O_5$ at surface of two soils s were 1962 (A), 1613 (B) $mg{\cdot}kg^{-1}$, respectively. These concentrations are 3.2~6.5 times of $300{\sim}500mg{\cdot}kg^{-1}$, which is the optimum concentration for crop growth. Infiltration rates at surface of the soils were 3.54 (A), 2.85 (B) cm $hr^{-1}$, but percolation rates at soil horizons under the surface were below 0.3 (A), below 0.003 (B) cm $hr^{-1}$. These results would be because the surface soils were managed by tillage and crop planting etc., but soils under surface were formed with structural problems occurred at the formation time of agricultural land accumulated with rock-dust or a compaction by farm machines.

Emotion Recognition by Hidden Markov Model at Driving Simulation (자동차 운행 시뮬레이션에서 Hidden Markov Model을 이용한 운전자 감성인식)

  • Park H.H.;Song S.H.;Ji Y.K.;Huh K.S.;Cho D.I.;Park J.H.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.1958-1962
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    • 2005
  • A driver's emotion is a very important factor of safe driving. This paper classified a driver's emotion into 3 major emotions, can be occur when driving a car: Surprise, Joy, Tired. And It evaluated the classifier using Hidden Markov Models, which have observation sequence as bio-signals. It used the 2-D emotional plane to classfiy a human's general emotion state. The 2-D emotional plane has 2 axes of pleasure-displeasure and arsual-relaxztion. The used bio-signals are Galvanic Skin Response(GSR) and Heart Rate Variability(HRV), which are easy to acquire and reliable. We classified several moving pictures into 3 major emotions to evaluate our HMM system. As a result of driving simulations for each emotional situations, we can get recognition rates of 67% for surprise, 58% for joy and 52% for tired.

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Design of a Two-wheeled Balancing Mobile Platform with Tilting Motion (횡방향 틸팅 기능을 갖는 이륜 밸런싱 모바일 플랫폼 설계)

  • Kim, Sangtae;Seo, Jeongmin;Kwon, SangJoo
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.1
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    • pp.87-93
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    • 2014
  • Conventional two-wheeled balancing robots are limited in terms of turning speed because they lack the lateral motion to compensate for the centrifugal force needed to stop rollover. In order to improve lateral stability, this paper suggests a two-wheeled balancing mobile platform equipped with a tilting mechanism to generate roll motions. In terms of static force analysis, it is shown that the two-body sliding type tilting method is more suitable for small-size mobile robots than the single-body type. For the mathematical modeling, the tilting-balancing platform is assumed as a 3D inverted pendulum and the four-degrees-of-freedom equation of motion is derived. In the velocity/posture control loop, the desired tilting angle is naturally determined according to the changes of forward velocity and steering yaw rate. The efficiency of the developed tilting type balancing mobile platform is validated through experimental results.