• Journal of the Korean Geosynthetics Society
• /
• v.9 no.3
• /
• pp.67-75
• /
• 2010

The tensile strength, permeability and discharge capacity of biodegradable plastic drain boards made with poly lactic acid (PLA) have been tested and verified prior to their usage at field. Based on test results, the tensile strength of biodegradable plastic drain board made with PLA has relatively lower tensile strain and tensile strength than those of plastic drain board. Performance of PLA filter having good permeability and low opening size is proper for the filter of vertical drain board. In case of improving stiffness of PLA filter, biodegradable plastic drain board also satisfies required discharge capacity as use of vertical drain board too.

• Journal of the Society of Naval Architects of Korea
• /
• v.58 no.2
• /
• pp.112-120
• /
• 2021

The novel wave generating system of a wave flume has been devised by utilizing the analytic solution of wave board motion in idealized two dimensional space. The arbitrary oscillation motion of submerged wave board segment has been defined by sinusoidal motion of upper and lower end of the wave board. The analytic solution of the wave board motion has been represented by the solution of board motion due to flap motion and swing motion. Arbitrary oscillation of the board could be specified by determining amplitude, frequency, and the phase lag. A novel hybrid wave generator could be operated not only in piston motion but also in flap or swing motion by selection of control parameter. The wave generator has unique motion enhancing ability by appending flap motion or swing motion to piston motion in wave generation. In addition the hybrid wave generator has advantages in generating high quality wave spectrum of irregular wave in simulating real sea condition.

• Aerospace Engineering and Technology
• /
• v.4 no.2
• /
• pp.79-87
• /
• 2005

This paper describes a new on-board computer design for the next generation satellite. The new on-board computer utilizes centralized processing architecture with MCMERC325C CPU based on functional modular design concepts. The on-board computer consists of PM32 Module, TC-TM Module, IO Module and Power module. The IEEE-1355 DS/DE, or SpaceWire, provides a standard communication interface between module. It also provides simple cross-strap design for redundancy management and increases re-usability of the modules.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.1
• /
• pp.367-370
• /
• 2006

A GPS-based time synchronization technique employing a refined HW circuitry and SW algorithm is considered as fine time-management system for Low Earth Orbit (LEO) remote sensing satellites. By synchronizing the On-Board Time (OBT) within satellites to the GPS 1PPS, a very expensive, highly accurate on-board clock is not required to determine the precise on-board time management. Also, the satellite command generation in ground stations and postprocessing of earth observation data which a particular image is acquired. This paper analyses on-orbit verification of the existing satellite time sync architecture and presents a new time sync architecture, operation and relation between the OBT and the GPS time.

• Journal of Electrical Engineering and Technology
• /
• v.8 no.4
• /
• pp.951-958
• /
• 2013

This paper proposes the controller design for a stability improvement of an on-board battery charger. The system is comprised of a power factor correction (PFC) circuit and phase shift full-bridge DC-DC converter. The PFC circuit performs the control of the DC-link voltage and the input power factor. The DC-DC converter regulates the voltage and the current in the battery using the DC-link voltage. This paper proposes the design method of PI controller for the PFC circuit using a small signal model. The analysis and design of a type-three controller for the DC-DC converter is also presented. A simulation and experiment has been performed on the on-board battery charger and their results are presented to verify the validity of the proposed system.

• Journal of the Korean Wood Science and Technology
• /
• v.46 no.1
• /
• pp.60-66
• /
• 2018

For new use development of carbonized board, we investigated the effect of carbonization temperature on the surface temperature of carbonized board manufactured from a plywood, particle board, MDF, and wood of Fraxinus rhynchophylla at different carbonization temperature ($400^{\circ}C{\sim}1100^{\circ}C$). The surface temperature of carbonized board precipitously increased until 12 minutes elapsed, after smoothly increased and thereafter which were stable after 20 minutes. The higher carbonization temperature increased density of carbonized board and surface temperature of carbonized board so that density is considered to influence surface temperature change. Moreover, carbonized boards kept heat for a long time because the descent velocity of carbonized boards' surface temperature was slower than that of heater's.

• Journal of Forest and Environmental Science
• /
• v.31 no.2
• /
• pp.119-125
• /
• 2015

This study examined the effects of rice straw steaming time and mixing ratio between rice straw and wood particle on the properties of mixed particle board from Acacia mangium Willd wood and rice straw. Rice straw and Acacia mangium Willd wood were collected in Hanoi, Vietnam. The particle board was three-layer particle board with the structural ratio of 1:3:1. The thickness, density and board size of the particle board were 18 mm, $0.7g/cm^3$, and $800{\times}800{\times}18$ (mm, including trimming), respectively. A resin mixture between commercial Urea-formaldehyde (U-F) adhesive and methylene diphenyl isocyanate (MDI) adhesive was used with a dosage of 12% for the core layer and 14% for the surface layer. In this experimental design, the steaming time for rice straw was 15, 30, 45, 60, and 75 minutes at $100^{\circ}C$. The rice straw-wood mixing ratio was 10, 20, 30, 40, and 50%. The results showed that both mixing ratio and steaming time affect the properties of the particleboard, but the mixing ratio has a stronger impact. A higher mixing ratio and a longer steaming time resulted in a better quality of particleboard. The optimal steaming time for rice straw was 46.12 minutes with the straw-wood mixing ratio of 29.85% with the following characteristics of the particle board: the modulus of rupture (MOR) of 14.64 MPa, internal bond strength (IB) of 0.382 MPa, thickness swelling (TS) of 8.83%, and board density of $0.7-0.7g/cm^3$.

• Journal of the Institute of Convergence Signal Processing
• /
• v.22 no.4
• /
• pp.199-205
• /
• 2021

The distributing board in directly installed on the ground or the bottom surface of the building, and when vibrations such as earthquakes or external shocks occur, the possibility of damage or malfunction of electric components such as internal power devices, wiring, and protection relays increases. Recently, the need for a seismic type distributing board is increasing, and research and development of a distributing board having a vibration damping function and product launch are being conducted. In this paper, an IoT-based data collection device system capable of measuring vibration and environmental data of distributing board was designed and implemented. When vibration occurred on the distributing board, data was stored and visualized in the MySQL DB through Node-RED for monitoring and data storage using the MQTT protocol for reliable messaging transmission. The test was conducted by attaching the IoT device of the distributing board, and data was collected in real-time and monitored through Node-RED.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.9 no.1
• /
• pp.91-96
• /
• 2014

nowadays, many researches for plug-in hybrid electric vehicles have been actively carried out to improve the gas mileage in comparison with mass-produced hybrid electric vehicles. In this paper, the on-board charger for plug-in hybrid electric vehicles is studied for obtaining the high efficiency. The on-board charger consists of two phase interleaved PFC circuit and LLC resonant converter. The new design procedures of LLC resonant converter are proposed in this paper. These are very simple and powerful method. In order to verify the abovementioned contents, the LLC resonant converter is designed and tested by using PSIM tool.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.5
• /
• pp.703-712
• /
• 2014

To improve the efficiency and safety of railway systems, the train control system has been considerably evolved from the ground-equipment-based control system (e.g. track circuit, interlocking system, etc.) into the on-board-equipment-based control system. In addition, this train control system enables the rolling stock to intelligently control the trackside facilities by introducing the information and communication technologies (ICT). Accordingly, since the ICT-based train control system makes the railway system be simplified (i.e. the heavy ground-equipment can be removed), the efficient and cost-effective railway system can be realized. In this paper, we perform the feasibility test of the ICT-based train control system via a simulation. To this end, we have developed the prototypes of the on-board controller and wayside object control units which control the point and crossing gate and performed the integrated operation simulation in a testbed. In this paper, before the field test of the on-board-controller-based train control system, we perform the Consecutive operation test for prototypes of the on-board controller, wayside object control units and local control computer.