• Journal of Advanced Marine Engineering and Technology
• /
• 제33권1호
• /
• pp.44-51
• /
• 2009

The Characteristics of the flowfield through tube banks with in-line and staggered arrangements were investigated by PIV. Strouhal numbers, velocity vectors and velocity profiles around the cylinders with in-line and staggered arrangements were observed at the pitch ratio Pt/D=2.0 and Reynolds number of Re=$Re=4.0{\times}10^3$. As the results The flow patterns through tube banks were almost a straight line in case of the in-line arrangement while it was almost 八 type in case of the staggered arrangement in the direction of the wake. The average velocity in the rear region of the tube banks with the staggered arrangement was far smaller than that with the in-line arrangement. The Strouhal number in the last rank was far smaller than that in the front ranks in both of the in-line and staggered arrangements. The wake of each cylinder changed with time and with the position of the cylinder.

• 한국초전도ㆍ저온공학회논문지
• /
• 제17권2호
• /
• pp.31-35
• /
• 2015

Mapping is a useful tool in the magnetic field analysis and design. In some specific research area, such as the nuclear magnetic resonance (NMR) or the magnetic resonance imaging (MRI), it is important to map the magnetic field in the interesting space with high accuracy. In this paper, an indirect mapping method in the center volume of an air-core solenoid is presented, based on the solution of the Laplace's equation for the field. Through the mathematical analysis on the mapping calculation, we know that the condition number of the matrix, generated by the measurement points, can greatly affect the error of mapping result. Two different arrangement methods of the measurement points in field mapping are described in this paper: helical cylindrical line (HCL) method and parallel cylindrical line (PCL) method. According to the condition number, the HCL method is recommended to measure the field components using one probe. As a simple example, we mapped the magnetic fields in a MRI main magnet system. Comparing the results in the different methods, it is feasible and convenient to apply the condition number to reduce the error in the field mapping calculation. Finally, some guidelines were presented for the magnetic field mapping in the center volume of the air-core solenoid.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
• /
• pp.680-683
• /
• 1997

Fieldbus system should be designed by considering the number of sensors/actors(actuators+ controllers) and their sampling times. But the number of sensors/actors and which are connected to the network bus can be varied by addition and/or fault of the field devices. That variation decreases the efficiency of system which is off-line designed optimally. This paper proposes an algorithm that ensures transmission of cyclic data even though there is the number change in the field devices. We assign the different weight values to cyclic data and acyclic data. By simulation and experiment, the cyclic and acyclic data are processed via the proposed network, and the results are compared with those of the Profibus system. It is shown that the proposed algorithm is more robust with the uncertainties of the field devices of the control system.

• 한국시뮬레이션학회:학술대회논문집
• /
• 한국시뮬레이션학회 2001년도 The Seoul International Simulation Conference
• /
• pp.269-273
• /
• 2001

Semiconductor wafer fabrication is a business of high capital investment and fast changing nature. To be competitive, the production in a fab needs to be effectively planned and scheduled starting from the ramping up phase, so that the business goals such as on-time delivery, high output volume and effective use of capital intensive equipment can be achieved. In this paper, we propose Stand Alone layout and In-Line layout are analyzed and compared while varying number of device variable changes. The comparison is performed through simulation using ProSys; a window 98 based discrete system simulation software, as a tool for comparing performance of two proposed layouts. The comparison demonstrates that when the number of device variable change is small, In-Line layout is more efficient in terms of production quantity. However, as the number of device variable change is more than 14 titles, Stand Alone layout prevails over In-Line layout.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
• /
• pp.531-534
• /
• 2005

This paper presents a new data line sharing technique for TFT-LCD panels. This technique reduces the number of data driver IC's to half by having two adjacent pixels share the same data line. This in turn doubles the number of gate lines, which are integrated directly on the glass substrate of amorphous silicon for further cost reduction and more compactness. The proposed technique with new pixel array structure was applied to 15.4 inch WXGA TFT-LCD panels and has proven that the number of driver IC's were halved with nearly 41% circuit cost reduction and 5.3% reduction in power consumption without degrading the image quality.

• 한국철도학회논문집
• /
• 제8권6호
• /
• pp.507-512
• /
• 2005

Railroad transportation system has experienced major changes due to KTX introduction. Kyungbu corridor especially Seoul to Cheonan has line capacity problem and its solution has been a primary concern to researchers and policy decision makers. This study explored pattern of train operation between Seoul and Cheonan after the introduction of KTX in 2004. Both the number of trains and available seat capacity per day have increased but maximum number of trains per specific hour has not been changed much. Demand for train shows that if concentrated in a specific time, so number of trains during the peak hour should be increased. But, it is difficult ? 새 line capacity, so increasing seat capacity per train might be an option. An increase in an avaliable sear should be considered the characteristics of each train lines.

• Journal of Plant Biology
• /
• 제33권3호
• /
• pp.189-196
• /
• 1990

Suspension cell lines have been newly established from the calli derived from the immuature embryo culture of hexapolid (Triticum aestivum var. sicco), tetrapolid (T. durum) and diploid (T. tauchii or Aegilops squarrosa) wheat species. The chromosomal variation in suspension cultured cell lines was examined and old cell line, C82d, established from T. aestivum var. copain was also used. New method using 1-bromonaphthalene for metaphase rapping of suspension cells was developed. Variation in chromosome number was observed among all the suspension lines. Cells with doubled chromosome number and deleted chromosome were also observed. Extensive structural changes in chromosome were found in C82d line. Chromosome aberrations showed loss of chromosome arms and chromosome segment. The mean chromosome number in suspension cells of T. aestivum var. sicco was 40, in C82d line 33, in T. durum 28 and in T. tauchii 14. The stability of chromosome in suspension cells of diploid and tetrapolid wheats was higher than that of hexaploid wheat.

• 전기학회논문지P
• /
• 제55권3호
• /
• pp.141-145
• /
• 2006

The line current problem(2-dimensional space : point source) is not easy to analyze the magnetic field using the standard finite element method(FEM), such as overhead trolley line or transmission line. To supplement such a defect this paper is proposed the coupling scheme of analytical solution and FEM. In analysis of the magnetic field using the standard FEM. If the current region is a relatively small compared to the whole region. Therefore the current region must be finely divided using a large number of elements. And the large number of elements increase the number of unknown variables and the use of computer memories. In this paper, an analytical solution is suggested to supplement this weak points. When source is line current and the part of interest is far from line current, the analytical solution can be coupling with FEM at the boundary. Analytical solution can be described by the multiplication of two functions. One is power function of radius, the other is a trigonometric function of angle in the cylindrical coordinate system. There are integral constants of two types which can be established by fourier series expansion. Also fourier series is represented as the factor to apply the continuity of the magnetic vector potential and magnetic field intensity with tangential component at the boundary. To verify the proposed algorithm, we chose simplified model existing magnetic material in FE region. The results are compared with standard FE solution. And it is good agreed by increasing harmonic order.

• 한국작물학회지
• /
• 제28권3호
• /
• pp.310-318
• /
• 1983

본 시험은 식생분석법(vegetation analysis)에 많이 이용되는 4가지 분석방법 즉, List quadrat 방법, Clip quadrat방법, Point quadrat방법, Line intercept방법을 비교 분석하였다. 1. 분석 방법별로 얻어지는 초종수에 있어서는 List quadrat방법이 14종으로 가장 많았고, Line intercept방법이 8종으로 가장 적었다. 한편 Clip quadrat방법과 Point quadrat방법은 다같이 12종씩 기록되었다. 2. Clip quadrat방법은 여뀌바늘(Ludwigia prostrata Roxb), 벗풀(Sagittaria trifolia L.)등과 같이 수분함량이 비교적 적은 초종에 대해서는 지나치게 높은 우점도(Importance value)를 보이는 경향이며 반면 올미(Sagittaria Pygmaea Miq.) 또는 물달개비〔Monochoria vaginalis(Burm. f)〕와 같은 수분함량이 높은 초종에 대해서는 지나치게 낮게 우점도를 나타내는 경향이었다. 한편 Line intercept 방법은 벗풀(S. trifolia)와 가래(Potamogeton distinctus Benn.)등과 같이 넓은 잎을 가진 초종에 대해 높은 우점도를 나타내는 경향이었다. 3. 본 시험에 사용된 4가지 방법중에서 어느 방법을 선택하더라도 별다른 큰 문제점을 야기 시키지는 않았으나 작업과정중의 노력절감, 시간절약 또는 우점초종의 초종수 및 우점순위 등을 종합적으로 볼 때 Point quadrat방법이 가장 바람직하였고, Line intercept방법이 가장 바람직하지 못하였다.

• 대한수학회보
• /
• 제37권1호
• /
• pp.121-125
• /
• 2000

In this paper, we obtain an algorithm for finding a maximum matching in the line graph L(G) of a graph G. The complexity of our algorithm is O($$\mid$E$\mid$$), where is the edge set of G($$\mid$E$\mid$$ is equal to the number of vertices in L(G)).