• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.7
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• pp.681-686
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• 2009

Direct laser metal forming technology was applied to restore the damaged mold surface. In order to estimate melting characteristics of the $20{\mu}m$ Fe-Cr-Ni powder, single layer experiments were performed at various levels of heat input. The process window of the $20{\mu}m$ Fe-Cr-Ni powder provided feasible process parameters for the smooth regular surface. The cross hatching scanning strategy on the multiple layer experiment was performed to reduce the thickness non-uniformity of edge portions compared with the one direction scanning. To estimate the coherence between the melted powder and the basematal, the tendency of hardness distribution has been observed. The hardness of the melted and the remelted zone was distributed from 400HV to 600HV. It is over 2 times compared of the hardness of the basemetal. Experimental results show that the mold restoring process using direct laser metal forming can be successfully applied in the mold repair industry.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.5
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• pp.490-498
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• 2011

In this paper, we present a two-stage vision-based approach to detect multi views of pedestrian in road scene images. The first stage is HG (Hypothesis Generation), in which potential pedestrian are hypothesized. During the hypothesis generation step, we use a vertical, horizontal edge map, and different colors between road background and pedestrian's clothes to determine the leg position of pedestrian, then a novel symmetry peaks processing is performed to define how many pedestrians is covered in one potential candidate region. Finally, the real candidate region where pedestrian exists will be constructed. The second stage is HV (Hypothesis Verification). In this stage, all hypotheses are verified by Support Vector Machine for classification, which is robust for multi views of pedestrian detection and recognition problems.

• Journal of the Korea Convergence Society
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• v.11 no.5
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• pp.191-197
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• 2020

OFDI is one of the key issues around the world in the development of economics, in 2013, Chinese President Xi JinPing proposed "One Belt One Road" initiative on conference of Asia-Africa international conference with its core policy as (Outward Foreign Direct Investment).With the steady development of China's "One Belt One Road", further advancement of Korea-China FTA, and rapid expansion of close economic relations between two countries, China is bound to increase OFDI to Korea. The paper empirically studied its determinants of Chinese OFDI to Korea, with PANELDATA data introduced combining time series with cross-section, result shows GRDP, HV, YNTL, FWYS, XFZS are all verified as determinants of Chinese OFDI to Korea, while, several suggestions are proposed for Korea to attract Chinese OFDI.

• Journal of Technologic Dentistry
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• v.35 no.4
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• pp.287-293
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• 2013

Purpose: This study is to provide basic data of the dental acrylic denture base resin in the mechanical property difference investigation according to the monomer composition weight ratio of the acrylic denture base resin. Methods: The monomer composition of the acrylic denture base resin and weight ratio makes the different specimen. It measured the mechanical property with the specimens through Hardness Test, Tensile Test, Flexural Test, Flexural Modulus, FT-IR Test. Results: The control group Vertex was 18.4 Hv and the experimental group MED was 14.46~19.07Hv in the hardness test. Vertex was 364N, MED-3 was lowest in the tensile strength test and the Head of a family cursor declination was big. The result declination of the experimental specimens showed. Vertex and MED-2 was the highestest in the flexural test and after coming MED-6, MED-5, MED-1, MED-3, MED-4. Vertex and MED-2, as to a spectrum for $500{\sim}1800cm^{-1}$ peak can show the excellent degree of polymerization in the FT-IR Test. Conclusion: The ideal weight ratio of the monomer of the acrylic denture base resin of which the mechanical property is the highestest was MMA 100g, EDGMA 5g, DMA 0.2g, of MED-2.

• Microbiology and Biotechnology Letters
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• v.28 no.4
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• pp.239-241
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• 2000

From 5 forest soil samples, the isolation frequency of oligotrophic Actinomycetes was investigated with nutrient and minimal media. The frequency of soil Actinomycetes by the minimal media. The frequency of soil Actinomycetes by the minimal media of DHV, WA, BA and NA was similar to the value by HV nutrient medium. In addition, different Actinomycetes were isolated from all the media used in this experiment and then their growth were tested on nutrient (Bennett's agar) and minimal media(WA). In consequent, the number of different Actinomycetes from minimal media was 26.1 strains, whereas the number of from nutrient medium (HV) was 26.6 strains. Furthermore, the percentage of facultative and obligate strains among the oligotrophic Actinomycetes was 90% and 10%, respectively.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.5
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• pp.711-716
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• 2012

To assess the insulation deterioration of stator windings, diagnostic and AC breakdown tests were performed on the eleven high voltage (HV) motors rated at 6kV. After completing the diagnostic tests, the AC overvoltage test was performed by gradually increasing the voltage applied to the stator windings until electrical insulation failure occurred, to obtain the breakdown voltage. Stator winding of motors 1, 3, and 8 failed at above rated voltage at 14 kV, 13.8kV, and 16.4kV, respectively. The breakdown voltage of three motors was higher than expected for good quality windings in 6kV motors. Based on deterioration evaluation criteria, the stator winding insulation of eleven HV motors are confirmed to be in good condition. The turning point of the current, $P_{i2}$, in the AC current vs. voltage characteristics occurred between 5kV and 6kV, and the breakdown voltage was low between 13.8kV and 16.4kV. There was a strong correlation between the breakdown voltage and various electrical characteristics in diagnostic tests including Pi2.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.12
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• pp.627-632
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• 2001

There are claims that ESE(Early streamer emission) Air terminals offer a vastly increased zone of protection over that of traditional lightning rods by causing the emission of an upward streamer/leader that will propagate towards the tip of downward leader at an early stage in the attachment process than would occur for a simple rod in the same geometrical configurations. This paper shows the results of comparing test a particular type of ESE air terminals with a simple rod conducted in the KEH HV laboratory, which are lightning impulse voltage test, flashover direction test and corona emission current measurement. The results from this test show a completely random scattering of flashovers to the conventional and ESE air terminals under identical electrics] and geometrical conditions, and thus shows no advantage of one terminal over the other.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05a
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• pp.50-54
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• 2000

Recently, the HFPD measurement testing is widely used in partial discharge measurement of HV machines because HFPD measurement testing receives less influence of external noise and has a merit of good sensitivity. Also HFPD testing is able to offer the judgement standard of degradation level of HV machine and can detect discharge signals in live-line. Therefore it is very useful method compare to previous conventional PD testing method and effective diagnosis method in power transformer that requires live-line diagnosis. But partial discharges have very complex characteristics of discharge pattern so it is required continuous research to development of precise analysis method. In recent, the study of partial discharge is carrying out discover of initial defect of power equipment through condition diagnosis and system development of degradation diagnosis using HFPD(High Frequency Partial Discharge) detection. In this study, simulated transformer is manufactured and HFPD occurred from transformer is measured with broad band antenna in real time, the degradation grade of transformer is analyzed through produced patterns in simulated transformer according to applied voltages.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.10
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• pp.786-790
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• 2012

A variety of diagnostic tests are widely applied in the field in industry to evaluate the condition of high voltage (HV) motor stator insulation. In this paper, the influence of temperature on the stator insulation diagnostic tests such as the insulation resistance, AC current, dissipation factor, and partial discharge measurements are studied and reported. The tests are performed with the HV motor stator winding temperature set between $40^{\circ}C$ to $80^{\circ}C$ in $10^{\circ}C$ intervals. It is shown that the AC current, dissipation factor, and partial discharge magnitude steadily increase with temperature, which suggests that temperature must be taken into account in the interpretation of the test results.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.199-200
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• 2006

PM recent developments focus on increasing this technology's competitiveness when compared to wrought materials. Warm compaction allows the replacement of a double press double sinter process with a single warm press and sintering step, thus allowing cost and time savings. Moreover there are added benefits to consider such as reducing work in process and lessening part's logistics cost. This paper presents a successful industrial trial to replace a double press-double sinter process with a warm die compaction and sintering process. The part chosen was a high performance gear containing 0,9% wt. carbon. Sintering was conducted in a belt furnace at $1120^{\circ}C$ in a nitrogen rich atmosphere with rapid cooling process in order to obtain a quasi fully martensitic structure with a minimum of 700HV0,1 and 450HV10 after annealing. The balance between properties and cost is favoured by the use of a singular lubricant developed in a Eureka frame project together with POMETON S.A. and die warm compaction. Warm compaction is only needed to be effective on the gear teeth, in order to achieve the required properties. Therefore only the die is actually heated. This simplified system avoids flow rate problems typically involved when using more elaborate warm compaction equipments.