• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.33 no.2
• /
• pp.140-147
• /
• 2010

The defense M&S (Modeling and Simulation) techniques are being used by the ROK Army for developing the efficiency and economics of national defense at operational level. But the problem we have found is the lack of interoperability and reusability in defense M&S. CMMS (Conceptual Model of the Mission Space) method have been used by militaries of some advanced countries for the purpose to solve these problems. Therefore, we have adapted the same approach in this paper as adapted by advanced countries military forces as named it as K-CMMS(Korean-Conceptual Model of the Mission Space). Considering the special ROK factors, we have suggested the framework of K-CMMS. We have tried to search for improving the reusability and interoperability in defense M&S.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.23 no.6
• /
• pp.39-50
• /
• 2019

Modeling and Simulation(M&S) for a liquid propellant supply system is a technique to predict the performance of components and systems under certain conditions based on mathematical modeling for each component of the engine. In this paper, the basic structure of M&S for the supply system applied to liquid rocket engines was obtained by analyzing the related research conducted. The basic mathematical modeling of components was organized and the characteristics of each study result were analyzed. Based on the analysis and validation results, M&S method of advanced foreign research institutes was also identified, and factors related to its accuracy were described.

• International Journal of Precision Engineering and Manufacturing
• /
• v.5 no.3
• /
• pp.54-61
• /
• 2004

This paper describes the development of a 6-axis robot's finger force/moment sensor, which measures forces $F_x$(x-direction force), $F_y$and $F_z$, and moments $M_x$ (x-direction moment), $M_y$ and $M_z$ simultaneously, for stable grasping of an unknown object. In order to safely grasp an unknown object using the robot's gripper, the force in the gripping direction and the force in the gravity direction should be measured, and the force control should be performed using the measured forces. Also, the moments $M_x$, $M_y$ and $M_z$ to accurately perceive the position of the object in the grippers should be detected. Thus, the robot's gripper should be composed of 6-axis robot's finger force/moment sensor that can measure forces $F_x$, $F_y$ and $F_z$, and moments $M_x$ $M_y$ and $M_z$ simultaneously. In this paper, the 6-axis robot's finger force/moment sensor for measuring forces $F_x$, $F_y$ and $F_z$, and moments $M_x$ $M_y$ and $M_z$ simultaneously was newly modeled using several parallel-plate beams, designed, and fabricated. The characteristic test of the fabricated sensor was performed, and the result shows that interference errors of the developed sensor are less than 3%. Also, Robot's gripper with the 6-axis robot's finger force/moment sensor for the characteristic test of force control was manufactured, and the characteristic test for grasping an unknown object using the sensors was performed using it. The fabricated gripper could grasp an unknown object stably. Thus, the developed 6-axis robot's finger force/moment sensor can be used for robot's gripper.

• Wind and Structures
• /
• v.35 no.3
• /
• pp.147-155
• /
• 2022

This research proposes a wind-lens turbine design that can startup and operate at a low wind speed (< 5m/s). The performance of the wind-lens turbine was investigated using CFD and wind tunnel testing. The wind-lens turbine consists of a 3-bladed horizontal axis wind turbine with a diameter of 0.6m and a diffuser-shaped shroud that uses the suction side of the thin airfoil SD2030 as a cross-section profile. The performance of the 3-bladed wind-lens turbine was then compared to the two-bladed rotor configuration while keeping the blade geometry the same. The 3-bladed wind-lens turbine successfully startup at 1m/s and produced a torque of 66% higher than the bare turbine, while the two-bladed wind-lens turbine startup at less than 4m/s and produced a torque of 186 % higher than the two-bladed bare turbine at the design point. Findings testify that adding the wind-lens could improve the bare turbine's performance at low wind speed.

• Applied Chemistry for Engineering
• /
• v.19 no.5
• /
• pp.484-490
• /
• 2008

Electrospun of PVP (polyvinylpyrrolidone) ultra fine fibers were fabricated using various solvents including methanol, ethanol, 2-propanol, butanol, acetone, methylene chloride, and DMF, which possess different properties such as boiling point, dielectric constant, and dipole moment. Electrospun PVP fiber was influenced by viscosity, conductivity, and surface tension of spinning solution. Therefore, the electrospun PVP fiber was successfully prepared under critical conditions of viscosity > $0.114kg/m{\cdot}s$, conductivity > 1.02 mS/m, surface tension < 30.0 mN/m. In case of an ethanol solvent system, average diameter of PVP fiber increased from 1701 nm to 5454 nm as increased the applied voltage from 10 kV to 20 kV.

• Fire Science and Engineering
• /
• v.32 no.5
• /
• pp.6-14
• /
• 2018

This study was carried out with respect to the heat release rate (HRR) properties of building wood. Heat release characteristics were measured using a cone calorimeter (ISO 5660-1) with four kinds of wood. The time to ignition measured after the combustion in $25kW/m^2$ external heat flux was 35 to 55 s. Time to ignition of both lauan and red pine was marked with the most delayed value in each of 54 s, 55 s. The maximum heat release rate ($HRR_{peak}$) was $156.87{\sim}235.1kW/m^2$, and the risk of early fire was highest in spruce. Total heat release of red pine was obtained in the highest value with $114.2MJ/m^2$. The mean effective heat of combustion of Japanese cedar was 19.1 MJ/kg and the highest among the samples. Fire risk of wood by FPI was orderly increased from lauan ($0.2468s{\cdot}m^2/kW$), red pine ($0.2339s{\cdot}m^2/kW$), spruce ($0.2308s{\cdot}m^2/kW$) to Japanese cedar ($0.2231s{\cdot}m^2/kW$). Fire risk of wood by FGI get increased from lauan ($0.5088kW/m^2{\cdot}s$), red pine ($0.5111kW/m^2{\cdot}s$), Japanese cedar ($2.8522kW/m^2{\cdot}s$) to spruce ($3.0662kW/m^2{\cdot}s$). Therefore, the risk of fire on the heat release characteristics of woods were found that spruce and Japanese cedar showed the high value compared with the other specimens.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.6
• /
• pp.631-640
• /
• 2011

This paper proposes a M & S Tool for simulating the detection performance in the bistatic radar system. After examing the interrelationship among the bistatic radar parameters, $P_d$(probability of detection), $P_{fa}$(probability of false alarm) and ��SNR of the received signal, we analyze the range of the bistatic radar range product and range sum. We derive the number of integration of the received pulses that satisfies the required detection performance of the bistatic radar system, along with the analysis of the performance degradation in the jammer scenario. Finally, the analyzed results are implemented in the M & S Tool which consists of 4 modules.

• Journal of Korean Institute of Industrial Engineers
• /
• v.30 no.3
• /
• pp.250-260
• /
• 2004

This study considers a linear connected-(r,s)-out-of-(m,n):F lattice system whose components are ordered like the elements of a linear (m,n )-matrix. We assume that all components are in the state 1 (operating) or 0 (failed) and identical and s-independent. The system fails whenever at least one connected (r,s)-submatrix of failed components occurs. The purpose of this paper is to present an optimization scheme that aims at minimizing the expected cost per unit time. To find the optimal threshold of maintenance intervention, we use a genetic algorithm for the cost optimization procedure. The expected cost per unit time is obtained by Monte Carlo simulation. The sensitivity analysis to the different cost parameters has also been made.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09b
• /
• pp.997-997
• /
• 2006

• Journal of Ocean Engineering and Technology
• /
• v.27 no.1
• /
• pp.24-30
• /
• 2013

The Korea Navy has been making constant efforts to apply M&S (modeling and simulation) to naval ship development, and the generalization of M&S for ship development is a trend. M&S for ship design is used for the V&V (verification and validation) of its design and operation, including design verification and ergonomic design that considers the crew using the Naval Ship Product Model. In addition, many parts of this M&S are repeatedly accomplished regardless of the kinds of ships. This study aims to standardize M&S, which repeatedly applies similar verifications for operation scenarios. A congestion assessment simulation for the major spaces of ships was the subject of the standardization based on the leading research results of various researchers, and a simulation automation solution was suggested. An information model using XML was proposed through the simulation automation concept, and a prototype system based on it was implemented. The usability was shown through a case study that verified the operability performance of the crew messroom.