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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Marine Engineering
Journal Basic Information
Journal DOI :
Korean Society of Marine Engineers
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Volume & Issues
Volume 21, Issue 5 - Oct 1997
Volume 21, Issue 4 - Aug 1997
Volume 21, Issue 3 - Jun 1997
Volume 21, Issue 2 - Apr 1997
Volume 21, Issue 1 - Feb 1997
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The Comparison Study of Radiative and Convective Heat Transfer in a Room Air Ventilation
Journal of the Korean Society of Marine Engineering, volume 21, issue 3, 1997, Pages 229~235
The comparison of radiative and convective heat transfer in a room air ventilation is investi¬gated by a numerical simulation. The room air temperature distributions with radiation are appeared more uniform than without radiation at Gr= 1460 and Re=50. The mean Nusselt number in the radiative heat transfer shows less value than convective heat transfer. The total mean Nusselt number is found Wall 1> Wall 3
Wall 2 7 Wall 4.
A Study on the Comparison Between Experimental and Numerical Analysis for Developing Turbulent Steady Flows in the Entrance Region of a Square Duct
Journal of the Korean Society of Marine Engineering, volume 21, issue 3, 1997, Pages 236~245
The flow characteristics of developing turbulent steady flow are investigated numerically and experimentally in the entrance region of a square duct (
and 4, 000 mm). The numerical anaysis are incorporated by finite- volume discretization with staggered grid system and SIMPLE algorithm. The numerical solution are compared with experimental results of mean velocity profiles, turbulence intensity and entrance length. For turbulent steady flow, the turbulent components in the velocity waveforms increase as the dimensionless transverse position approaches the wall. Thrbulence intensity increases as the dimensionless transverse position increases from the center to the wall of the duct for the developing turbulent steady flows. The entrance length of the turbulent steady flow is about 40 times as large as the hydraulic diameter under the present experimental condition.
A Study on the non -linearity of wave washer spring
Journal of the Korean Society of Marine Engineering, volume 21, issue 3, 1997, Pages 246~255
The wave washer springs are expected to behave non-linearly between forces and displace¬ments due to contractions of the height and due to expansions in radial direction. To find out the non -linearity of wave washer springs, the three dimensional plate analysis theory using the finite element method is adopted in this paper. The wave washer springs are considered to be three dimensional plate structures rather than frame structures, because their thickness is normally much smaller than their width. The displacements of nodal points due to small increment of force are calculated by the finite element method and the calculated nodal displacements are added to X - Y Z coordinates of nodal points. The new stiffness matrix of the system using the new coordinates of nodal points is adopted to calculate the another nodal displacements, that is, the step by step method is used in this paper. The relations between the increments of forces and displacements in each step are recorded and plotted in chart. The experimental results are compared with the calculated chart and it is shown that there are good coincidences between measured values and calculated ones.
On Development of Vibration Analysis Algorithm of Beam with Multi - Joints(II)
Journal of the Korean Society of Marine Engineering, volume 21, issue 3, 1997, Pages 256~266
The authors apply the transfer influence coefficient method to the 3. dimensional vibration analysis of beam with multi - joints and formulate a general algorithm to analyse the longitudinal, flexural and torsional coupled forced vibration. In this paper, a structure which is mainly found in the robot arms, cranes and so on, has some crooked parts, subsystems and joints, but has no closed loop in this system. It is modeled as the beam of a distributed mass system with massless translational, rotational and torsional springs in each node, and joint elements of release or roll at node which the displacement vector is discontinuous. The superiority of the present method to the transfer matrix method in the computation accuracy was confirmed from the numerical computation results. Moreover, we confirmed that boundary and intermediate conditions could be controlled by varying the values of the spring constants.
Study on the Steady-State Heat Conduction Characteristics of a Small Gasoline Engine
Journal of the Korean Society of Marine Engineering, volume 21, issue 3, 1997, Pages 267~277
In this paper, heat conduction characteristics of the cylinder block of a small 3 - cylinder, 4¬stroke gasoline engine were analyzed using the 3 - dimensional finite element method. Based on the experimental data, the engine cycle simulation was carried out in order to obtain the heat transfer coefficient and the temperature of the gas and the mean heat transfer coefficient of the coolant. Heat transfer data of the gas, which were averaged with respect to exposure time to the wall, were taken as convective boundary conditions corresponding to the operating conditions to obtain the temperature fields of the block. Finally silicon nitride(Si3N4) was taken as the material of the block liner in order to investigate its temperature distribution characteristics and compare the results with the original ones.
A Study on Technical Trends in Telecom Rectifier Plant
Journal of the Korean Society of Marine Engineering, volume 21, issue 3, 1997, Pages 278~283
The rectifier is the main element in the telecom DC power system. This paper investigates the advantages and disadvantages of three rectifier techniques ; thyristor, ferro - resonant, and switched - mode. Compared with other techniques, the switched - mode rectifier tech¬nique offers several advantages such as higher efficiency, smaller size and weight, and lower audible noise. Technical requirements in telecom rectifier plant are also described. Finally, the future trends in telecom powering are discussed in connection with the advance oftelecom net¬works.
A Study on Position Control of the Direct Drive Robot Using Neural Networks
Journal of the Korean Society of Marine Engineering, volume 21, issue 3, 1997, Pages 284~292
This paper is concerned with position control of direct drive robots. The proposed algorithm consists of the feedback controller and neural networks. Mter the completion of learning, the output of the feedback controller is nearly equal to zero, and the neural networks play an important role in the control system. Therefore, the optimum retuning of control parameters is unnecessary. In other words, the proposed algorithm does not need any knowledge of the con¬trolled system in advance. The effectiveness of the proposed algorithm is demonstrated by the experiment on the position control of a parallelogram link-type direct drive robot.
Cost Maximization Approach to Edge Detection Using a Genetic Algorithm
Journal of the Korean Society of Marine Engineering, volume 21, issue 3, 1997, Pages 293~301
Edge detection is the first step and very important step in image analysis. We cast edge detec¬tion as a problem in cost maximization. This is acheived by the formulation of a cost function that evaluates the quality of edge configurations. The cost function can be used as a basis for compar¬ing the performances of different detectors. We used a Genetic Algorithm for maximizing cost func¬tion. Genetic algorithms are a class of adaptive search techniques that have been intensively stud¬ied in recent years and have been prone to converge prematurely before the best solution has been found. This paper shows that carefully chosen modifications(three factors of the crossover opera¬tor) are implemented can be effective in alleviating this problem.
A Study on the Combustion Characteristics and Stratification for Lean Burn of Methanol (The Combust ion Character istics in a IDI Type Constant Volume Combustion Chamber)
Journal of the Korean Society of Marine Engineering, volume 21, issue 3, 1997, Pages 302~310
In this paper, we find a method to improve ignitability using methanol which is prospective as an alternative fuel. The constant volume combuster is divided into main chamber and sub-cham¬ber. These two chambers are linked by an adapter which is shaped like a cup. We also compare CDI to HIS that is revised in our laboratory for making a scrutiny into the effects of ignition char¬acteristics. Besides, we analyze a flame propagation process in the main and sub-chamber through taking pictures 10, 000 frames per second by high speed camera at the state being fabricated quartz glass aside main and sub-chamber.
A Study on Temperature Process Control of Electric Furnace
Journal of the Korean Society of Marine Engineering, volume 21, issue 3, 1997, Pages 311~318
In this paper, a controller with monitoring functions is proposed for controlling temperature of an electric furnace system. The controller includes holding and ramp control functions, and the control program for the temperature process monitor of the electric furnace. For this purpose, the implementation and performance of auto tuning algorithms in a computer¬based controller is studied in relation to control of a nonlinear electric furnace system which is characterized with large time delay. The communicator of a control and detection signals, between the controller and the electric furnace is implemented by an I/O data card. Experiments for the practical electric furnace are performed to illustrate the performance of the proposed controller.