• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2003년도 춘계공동학술대회
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• pp.721-728
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• 2003

Nowadays, a lot of enterprise completed the ERP implementation and these ERP-based enterprises consider the construction of WMS or already have done it. However the enterprises which Implemented WMS linked with ERP have many problems In the warehouse management and the reason ran be summarized In two poults First. In the integration point of view, only Interface issue between ERP and WMS was taken into account, therefore it was hard to reflect the phased process change. Second, a large number of WMS functions were tried to implement at the same tune and these attempts caused confusion and Instability which Is Interpreted as a main reason of the WMS failure. This paper presents the phased construction method for the successful implementation or WMS and in the integration point or view, the phased process change appears naturally

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.78-81
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• 2003

Polishing Processes are widely used in the glass, optical, die and semiconductor industry and are conventionally carried out using abrasive slurry and a polishing pad. But abrasive slurry process has a weak point that is high cost of handling of used slurry and hard controllability of slurry. Recently, some researches have attempted to solve these problems and one method is the development of a fixed abrasive pad. FAP has a couple of advantages including clean environment, lower CoC, easy controllability and higher form accuracy. But FAP also has a weak point that is need of dressing because of glazing and loading. The paper introduces the basic concept and fabrication technique of FAP using hydrophilic polymers with swelling characteristics in water and explains the self-conditioning phenomenon. Experimental results demonstrate to achieve nano surface roughness of soda lime glass for optical application

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2002년도 정기학술대회
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• pp.227-233
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• 2002

Suspension system is one of the most important components indespensible for stability and reliability of automobiles. The demands to more safe and durable suspension system have been increased as the automobiles get popular and improve in quality. The crack in the coil spring of the suspension system produced during manufacturing may grow under a fatigue load and cause a severe safety problems which lead to a catastrophic damage to the passengers. Many conventional NDT techniques including ET, RT, and UT are less sensitive or hard to apply to detect the surface breaking crack in the suspension coils partly because the techniques are point-to-point measurement methods, thus take too long time to inspect the coil spring longer than 1m. Contrary to this, Lamb wave technique is full-field measurement method that make it possible to examine the whole coil spring in real time. In this paper, the Lamb wave is applied to the coil spring to investigate the possibility to detect the cracks on the surface of the coil spring.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.351-356
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• 2011

Some materials show the character of rigid body in low frequency spectrum. The rigid body motions are consisted of translational and rotational motions. Especially, we can get the acceleration or displacement of a random point in the rigid body by analyzing rigid body transfer matrix at the car's engine and power train. Actually it is difficult to measure the acceleration by attaching the sensor inside of the engine and power train. So the hard to predict acceleration data can be achieved attaching the sensor on the outside of the engine and power train by analyzing the data of rigid body motion which the engine is operated using dynamo. Also this paper will show the change of predicted data and accuracy variation by not using all the measured data but a few exceptions of the point number.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제6권2호
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• pp.9-24
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• 2002

Total Variation(TV) regularization method is effective for reconstructing "blocky", discontinuous images from contaminated image with noise. But TV is represented by highly nonlinear integro-differential equation that is hard to solve. There have been much effort to obtain stable and fast methods. C. Vogel introduced "the Fixed Point Lagged Diffusivity Iteration", which solves the nonlinear equation by linearizing. In this paper, we apply multigrid(MG) method for cell centered finite difference (CCFD) to solve system arise at each step of this fixed point iteration. In numerical simulation, we test various images varying noises and regularization parameter $\alpha$ and smoothness $\beta$ which appear in TV method. Numerical tests show that the parameter ${\beta}$ does not affect the solution if it is sufficiently small. We compute optimal $\alpha$ that minimizes the error with respect to $L^2$ norm and $H^1$ norm and compare reconstructed images.

• 대한의용생체공학회:의공학회지
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• 제8권2호
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• pp.117-117
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• 1987

The medical image processing system is intended for a diverse set of users in the medical Imaging Parts. This system consists of a 640 Kbyte IBM-PC/AT with 30 Mbyte hard disk, special purpose image processor with video input devices and display monitor. Image may be recorded and processed in real time at sampling rate up to 10 MHz. This system provides a wide range of image enhancement processing facilities via a menu-driven software packages. These facilities include point by point processing, image averaging, convolution filter and subtraction.

• 반도체디스플레이기술학회지
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• 제10권3호
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• pp.35-42
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• 2011

This paper describes the characteristics of high speed grinding and the influence of wheel surface speed V and a grindability of the grinding materials. The various fine ceramics pieces was ground by metal and vitrified bonded diamond wheel. The surface roughness of fine ceramics(Zirconia($ZrO_2$), Silicon Carbide(SiC), Silicon Nitride($Si_3N_4$), Alumina($Al_2O_3$)) decreases from $0.05{\mu}m(R_{max})$ to $0.025{\mu}m(R_{max})$ when the wheel speed at grinding point increases the wheel speed. Relation between the temperature at grinding point and surface roughness was linear. Abrasive jet machining(AJM), a specialized from of shot blasting, is considered one of the most helpful micro machining methods for hard and brittle materials such as glasses and ceramics by constant pressure grinding.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권9호
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• pp.1596-1612
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• 2011

Coordinated Multi-Point (CoMP) transmission / reception is being studied in Long Term Evolution-Advanced (LTE-A) for future evolution of the $3^{rd}$ Generation Partnership Project (3GPP) LTE. Support of soft handover is essential for improving the performance of cell edge users. CoMP provides a natural framework for enabling soft handover in the LTE system. This paper evaluates the soft handover gain in LTE-A downlink. Mathematical analysis of signal to interference plus noise ratio (SINR) gain and the handover margins for soft handover and hard handover are derived. CoMP system model is developed and an inter-cell and intra-cell interference model is derived, taking into account the pathloss, shadowing, cell loading, and traffic activity. Reference signal received power (RSRP) is used to define the triggers and the measurements for soft handover. Our results indicate that parameter choices such as handover margin and the CoMP set size impact CoMP performance gain.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.132-137
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• 2006

Supercooled type ice slurry system is hard to keep a proper supercooling degree when solution becomes supercooling state. This is the reason of the ice blockage in pipe or cooling part due to an unstable cooling state. In this study, a cooling experiment was performed to pressurized solution in a stationary state. The behaviors during the supercooled aqueous solution were investigated at fixed flow rate of brine and aqueous solution of ethylene glycol 7 mass%. Also the effect to the freezing point of supercooled aqueous solution was investigated to the different pressure 101, 202, 303, and 404 kPa. At results, the pressure of the aqueous solution in the cylinder increased the supercooling degree increased and dissolution of supercooled point decreased.

• Journal of Power Electronics
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• 제19권5호
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• pp.1182-1192
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• 2019

In order to improve the conversion efficiency and mitigate the EMI problem of conventional hard-switching inverters, a new soft-switching DC-AC inverter with a compact structure and a low modulation complexity is proposed in this paper. In the proposed structure, resonant inductors are connected in series for the arm branches, and resonant capacitors are connected in parallel for the neutral point branches. With the help of resonant components, the proposed structure achieves zero-current switching on the arm branches and zero-voltage switching on the neutral point branches. When compared with state-of-art soft-switching topologies, the proposed topology does not need auxiliary switches. Moreover, the commutation algorithm to realize soft-switching can be easily implemented. In this paper, the principle of the resonant operation of the proposed soft-switching converter is presented and its performance is verified through simulation studies. The feasibility of the proposed inverter is evaluated experimentally with a 2.4-kW prototype.