• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.28 no.7
• /
• pp.19-25
• /
• 2014

In the LED lighting applications, because LED packages are the origin of heat generation, there are thermal design problem on heat sinks. In the thermal design, it is important to consider the total volume and the total weight of heat sink simultaneously. In this study, an Al 6063 heat sink was optimized using Computational Fluid Dynamics(CFD) simulation tool for the cooling of 30W LED module, and then the cooling performance and the total weight of heat sinks with Al 6063 and Thermal Conductive Polycarbonate(TCP) were compared under the same conditions. As the result of simulation, an Al 6063 heat sink was optimized with 22 ea. of fins and 1.6 mm of fin thickness. LED Junction Temperature of the TCP Heat Sink was $5.6^{\circ}C$ higher, but total weight of it was 47 % less than the Al 6063.

• Journal of the Korea Convergence Society
• /
• v.12 no.1
• /
• pp.185-191
• /
• 2021

A powder metallurgy process with granules is the manufacturing technology that can achieve higher-density sintered parts than conventional powder metallurgy processes. However, there is a disadvantage in that the production cost increases significantly due to the additional granulation step. High granule productivity must be guaranteed for affordable material costs in this manufacturing technology. This paper performed a series of scattering, collision, and adhesion simulations of agglomerated powders to investigate the characteristics of granulation process affecting the manufacturing yield rate. The results of this simulation-based convergence study can contribute to improving productivity in the metal powder spray granulation process.

• Design & Manufacturing
• /
• v.13 no.2
• /
• pp.54-59
• /
• 2019

CNC(Computer Numerical Control) machine tools are being used in various industrial fields such as aircraft and automobiles. The machining conditions used in the mold industry are used, and the simulation and the experiment are compared. The tool used in the experiment was carried out to increase the reliability of the simulation of the cutting machining. The program used in the 3D-FEM (finite element method) was the AdvantEdge and predicted by down-milling. The tool model is used 3D-FEM simulation by using the cutting force, temperature prediction. In this study, we carried out the verification of cutting force by using a 3-axis tool dynamometer (Kistler 9257B) system when machining the plastic mold Steel machining of NAK-80. The cutting force experiment data using on the charge amplifier (5070A) is amplified, and the 3-axis cutting force data are saved as a TDMS file using the Lab-View based program using on NI-PXIe-1062Q. The machining condition 7 was the most similar to the simulation and the experimental results. The material properties of the NAK-80 material and the simulation trends reflected in the reverse design of the tool were derived similarly to the experimental results.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.11 no.4
• /
• pp.325-330
• /
• 2001

It has been realized that the results of circuit level simulation of neural networks, used for optimization problems, arc much different from those of algorism level simulation. In other words, the outputs converges asymptotically as time elapes, however, the input convergence depends on the value of parasitic conductance connected between input node and ground. Also, this conductance affects system performance. This paper discusses the influence of input conductance on the convergece of the continuous Hopfield neural networks. The convergence has been analyzed for the input and output nodes of neurons. Also, the characteristics of equilibrium points has been analyzed depending on different values of the input conductance.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.24 no.4
• /
• pp.719-726
• /
• 1987

In this paper, an adaptive IIR (infinite impulse response) notch filter of lattice type is constructed and its adaptation algorithm is proposed for the detection and retrieval of a sine wave signal embedded in noise. A modified method which adapts only one coefficient of the filter is also suggested. All these methods adapt the coefficients while keepting the poles of the filter inside the unit circle on z-plane, and thus they satisfy the condition on the stability of the IIR filter after it has converged. To investigate the convergence characteristics of these methods such as convergence speed and output S/N ratio, intensive computer simulation has been performed by varying the frequency of the sine wave and the input S/N ratio. And the results of the simulation have been compared to those of Rao and Kung's which shows relatively fast convergence speed. The methods proposed here, especially the second one. shows faster convergence speed and higher output S/N ratio than the Rao and Kung's.

• Journal of Convergence for Information Technology
• /
• v.9 no.1
• /
• pp.151-157
• /
• 2019

As the interest in home furnishing becomes more focused due to the increase of small-sized households, the need for a virtual simulation system for this purpose is increasing. However, in the case of existing virtual simulation systems, simulation is performed using a virtual object in a virtual space, so accurate simulation results can not be derived. In the case of a simulation using an augmented reality, Thereby causing inconsistency in space. In this paper, we propose a system that performs the home furnishing simulation by modifying and enhancing objects in the process of matching feature coordinates of real space.

• ETRI Journal
• /
• v.34 no.6
• /
• pp.962-965
• /
• 2012

In this letter, we propose a new RESURF stepped oxide (RSO) process to make a semi-superjunction (semi-SJ) trench double-diffused MOSFET (TDMOS). In this new process, the thick single insulation layer ($SiO_2$) of a conventional device is replaced by a multilayered insulator ($SiO_2/SiN_x/TEOS$) to improve the process and electrical properties. To compare the electrical properties of the conventional RSO TDMOS to those of the proposed TDMOS, that is, the nitride_RSO TDMOS, simulation studies are performed using a TCAD simulator. The nitride_RSO TDMOS has superior properties compared to those of the RSO TDMOS, in terms of drain current and on-resistance, owing to a high nitride permittivity. Moreover, variations in the electrical properties of the nitride_RSO TDMOS are investigated using various devices, pitch sizes, and thicknesses of the insulator. Along with an increase of the device pitch size and the thickness of the insulator, the breakdown voltage slowly improves due to a vertical field plate effect; however, the drain current and on-resistance degenerate, owing to a shrinking of the drift width. The nitride_RSO TDMOS is successfully fabricated, and the blocking voltage and specific on-resistance are 108 V and $1.1m{\Omega}cm^2$, respectively.

• Journal of the Korean Society of Industry Convergence
• /
• v.10 no.4
• /
• pp.263-269
• /
• 2007

A numerical algorithm for three-dimension laminar flow in an agitated vessel was established by using the spherical coordinates. Flow pattern for the double-stage paddle impeller was not dependent upon the distance of among the impeller in the agitated vessels. The numerical simulation of the flow pattern in spherical and cylindrical agitated vessel agree well with the visualization results.

• Proceedings of the Korea Institute of Convergence Signal Processing
• /
• 2000.08a
• /
• pp.37-40
• /
• 2000

This paper represented the analytic results of outage probability, considering the effect of Rician fading, Interference and Interference-reduction techniques and simulated, when cellular system was constructed by using Stratospheric platform, one of the next generation wireless communication infras which provides high speed multimedia services.

• Journal of the Korean Society of Industry Convergence
• /
• v.23 no.3
• /
• pp.427-431
• /
• 2020

In this Study, as the structure of IT module for smart phone display becomes thin to catch up with slim product trend, the reliability of display module is on the rise as a issue for product design. Especially, almost part of cellular phone should undergo thermal dissipation test. thus many manufacturers have considered design guide line using CAE and simulation for more effective usage of limited resources on the market. This test simulates the case when cellular phone slips through user's fingers while he is talking on the phone. This paper studies a thermal simulation of display module in smart phone. This design for reliability improvements are suggested on the basis of the results of FVM Analysis and display of IT module and smart phone design.