• Title/Summary/Keyword: DLM

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Characterization of Direct Laser Melting Technology for the Fabrication of Fuel Cell Bipolar Plate (연료전지용 금속 분리판 제작을 위한 DLM공정 특성 연구)

  • Mun, S.M.;Jang, J.H.;Kim, T.H.;Lee, H.J.;Moon, Y.H.
    • Transactions of Materials Processing
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    • v.20 no.2
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    • pp.118-123
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    • 2011
  • Manufacturing of the bipolar plate of a direct methanol fuel cell (DMFC) by direct laser melting technology (DLM) was attempted. The DLM technology is highly influenced by process parameters such as laser power, scan rate and layering height. Therefore, an analysis of the DLM technology was performed under various conditions. The bipolar plates were fabricated using the DLM process with 316L stainless steel (STS 316L) plates and powder. Powder melting trials at various energy density were performed in order to select a feasible melting range for a given laser power. The melting line height increases and eventually saturates when the energy density increases, but decreases when the laser power increases at a given energy density. For the estimation of the potential performance of the bipolar plate, the surface roughness and contact resistance of the DLM layer were also analyzed. The changes of line height and thickness are useful information to report when manufacturing bipolar plate of fuel cell through the DLM process.

Statistical Correction of Numerical Model Forecasts for Typhoon Tracks

  • Sohn, Keon-Tae
    • Communications for Statistical Applications and Methods
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    • v.12 no.2
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    • pp.295-304
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    • 2005
  • This paper concentrates on the prediction of typhoon tracks using the dynamic linear model (DLM) for the statistical correction of the numerical model guidance used in the JMA. The DLM with proposed forecast strategy is applied to reduce their systematic errors using the latest observation. All parameters of the DLM are updated dynamically and backward forecasting is performed to remove the effect of initial values.

Comparison of Physiological Activity in Different Parts of Dolsan Leaf Mustard (돌산 갓의 부위별 생리활성 작용의 비교)

  • 최명락;유은정;송상호;강동수;박종철
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.30 no.4
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    • pp.721-725
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    • 2001
  • Physiological activity in different parts of Dolsan leaf mustard (DLM) was investigated. To determine the physiological activity, DLM was crushed filtered centrifuged and then the supernatant was used as a sample. of 1%, 3% and 6%. By adding of improved root juice(20th day) with the concentration of 6% the cytotoxicity against HepG2 was the highest about 78.2%. And antioxidative effects in different parts of DLM was measured by using the DPPH method. Antioxidative effects was higher in all leaves than other parts. In particular antioxidative effects was the highest in leaves of traditional DLM at the 20th day of growth about 80.4%. In leaves of improved DLM at the 60th growth angiotensin-I converting enzyme inhibitory effect was the highest about 94.0%. Consequently there was not significant difference of physiological activity between improved and traditional DLM. However the cytotoxicity against HepG2 was the highest in roots of DLM. And the antioxidative and the ACE inhibitory effect in leaves of DLM were higher than those of other parts.

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The 3-hour-interval prediction of ground-level temperature using Dynamic linear models in Seoul area (동적선형모형을 이용한 서울지역 3시간 간격 기온예보)

  • 손건태;김성덕
    • The Korean Journal of Applied Statistics
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    • v.15 no.2
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    • pp.213-222
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    • 2002
  • The 3-hour-interval prediction of ground-level temperature up to +45 hours in Seoul area is performed using dynamic linear models(DLM). Numerical outputs and observations we used as input values of DLM. According to compare DLM forecasts to RDAPS forecasts using RMSE, DLM improve the accuracy of prediction and systematic error of numerical model outputs are eliminated by DLM.

Design of the Kernel Hardening in USB Driver for Linux DLM Function (리눅스 운영체제에서 DLM을 이용한 USB 디바이스 커널 하드닝 설계)

  • Jang, Seung-Ju
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.12
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    • pp.2579-2585
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    • 2009
  • It is an important problem without system breaking. Like this, to make a computer system operate normally, various commercial fault tolerant techniques are used. Almost commercial products of fault tolerant system consume much cost. This paper proposes kernel hardening technique that are reducing panic using DLM modue in Linux USB driver. I experimented the design technique in Linux O.S. By the experiment, the suggesting technique which includes USB module with DLMis working well.

Effect of Powder Morphology on the Deposition Quality for Direct Laser Melting (Direct Laser Melting 공정시 분말 형태가 적층 품질에 미치는 영향)

  • Lee, S.H.;Kil, T.D.;Han, S.W.;Moon, Y.H.
    • Transactions of Materials Processing
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    • v.25 no.3
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    • pp.195-202
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    • 2016
  • Direct laser melting(DLM) is an additive manufacturing process that can produce parts by solidification of molten metallic powder layer by layer. The properties of the fabricated parts strongly depend on characteristics of the metallic powder. Atomized powders having spherical morphology have commonly been used for DLM. Mechanical ball-milling is a powder processing technique that can provide non-spherical solid powders without melting. The aim of the current study was to investigate the effect of powder morphologies on the deposition quality in DLM. To characterize the morphological effect, the performances of spherical and non-spherical powders were compared using both single- and multi-track DLM experiments. DLM experiments were performed with various laser process parameters such as laser power and scan rate, and the deposition quality was evaluated. The surface roughness, cross-section bead shape and process defects such as balling or non-filled area were compared and discussed in this study.

Improved method of positioning accuracy using GPS/DR integration DLM filter (GPS/DR 통합 DLM 필터를 이용한 위치 정확도 향상 방안)

  • Jun, Byung-Cheol;Kim, Young-Ho
    • Proceedings of the Korea Information Processing Society Conference
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    • 2001.10b
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    • pp.1179-1182
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    • 2001
  • 본 논문에서는 차량합법시스템에서 위치정확도 향상을 위한 방법으로 GPS/DR 통합시스템을 사용하여 DLM(Dynamic Linear Model) 알고리즘을 적용한 개선된 통합필터를 제안하였다. GPS/DR 통합 시스템의 성능을 개선하기 위해서는 DR 센서의 오류요소를 정확히 모델링 하여야 한다. GPS 로부터 위치를 계산하기 위해서는 적어도 3개 이상의 가시위성이 필요하다. 그러나 도심지에서는 고층빌딩이나 가로수 등에 의한 장애물로 인해서 3개 이상의 가시위성을 확보하기가 힘든 경우가 많다. 본 논문에서는 가시위성의 확보가 힘든 고층 빌딩이나 가로수길 등에서도 우수한 성능을 보이는 GPS 의사거리 및 의사거리율 정보를 이용하는 CPS/DR 통합 DLM 필터를 이용하여 성능을 개선시키는 방법을 제시한다.

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A Study of USB Device Kernel Hardening Using DLM, in Linux Operating System (리눅스 운영체제에서 DLM을 이용한 USB 디바이스 커널 하드닝에 관한 연구)

  • Jang, Seung-Ju;Choi, Eun-Seok
    • Proceedings of the Korea Contents Association Conference
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    • 2009.05a
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    • pp.693-698
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    • 2009
  • Computer system to operate normally without interruption, is one of the important issues. Likewise, a computer system to operate without interruption, failure to endure a variety of techniques, development and commercial use is arranged. Most guards will take a lot of technique failure endure. In this paper on the Linux operating system, dynamic module (DLM) to connect using the USB device to use USB devices can cause the symptoms to reduce the kernel PANIC hadeuning technique for studying the kernel.

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The Design and Implementation of the Distributed MIDI Interface for Multimedia I/O Server (멀티미디어 입출력 서버를 위한 분산 MIDI 인터페이스의 설계 및 구현)

  • Jo, Byeong-Ho;Gang, Tae-Jin;Yu, Gi-Yeong;Lee, Gyeong-Hui;Gung, Sang-Hwan
    • The Transactions of the Korea Information Processing Society
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    • v.5 no.7
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    • pp.1680-1690
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    • 1998
  • 멀티미디어 입출력 서버인 MuX는 다양한 입출력 디바이스와의 인터페이스를 위해 장치독립적인 DLM(dynamic Linking Module)을 사용한다. 본 논문에서는 MuX 시스템의 입출력 디바이스 인터페이스 기능을 확장하기 위해서 MIDI(Musical Instrument Digital Interface)형식의 오디오 데이터를 처리할 수 있는 DLM을 추가하였다. MIDI 데이터의 특성과 MIDI 파일 형식을 분석하여 MIDI를 지원하는 디바이스와의 인터페이스를 위한 MIDI DLM(Dynamic Linking Module)과 파일을 지원하는 DLM을 설계하고 구현하였다.

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Effect of Process Parameters on Surface Roughness and Porosity of Direct Laser Melted Bead (DLM 공정시 공정변수에 따른 내부공극률과 표면조도 변화)

  • Kim, T.H.;Jang, J.H.;Jeon, C.H.;Moon, Y.H.
    • Transactions of Materials Processing
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    • v.20 no.8
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    • pp.575-580
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    • 2011
  • Direct laser melting(DLM) is promising as a joining method for producing parts for automobiles, aerospace, marine and medical applications. An advantageous characteristic of DLM is that it affects the parent metal very little. The mechanical properties of parts made by DLM are strongly affected by the porosity and surface roughness of the laser melted beads. This is a systematic study of the effects of the porosity and surface roughness of laser melted beads using various processing parameters, such as laser power, scan rate and overlapping ratio of the fill spacing. The specimens were fabricated with 316L and 304L austenitic stainless steel powder. Dense parts with low porosity were obtained at low laser scan speed, as it increased the aspect ratio of the parental material and the depth of penetration. The variations of surface roughness were examined at various processing parameters such as overlapping ratio and laser power.