• Title/Summary/Keyword: 리프터

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Influence of Adhesive Force of Lifter on the Quality of Powdered Fingermark (리프터의 점착력이 분말 처리된 지문의 품질에 미치는 영향)

  • Choi, Go-Woon;Hwang, Yun-Jung;Kim, Chae-Won;Yu, Je-Seol
    • The Journal of the Korea Contents Association
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    • v.19 no.5
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    • pp.624-631
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    • 2019
  • The purpose of this study was to observe the influence of adhesive force of lifter on powdered fingermark. First, an experiment was conducted to measure the adhesive force of five kinds of lifters. Second, each fingermark deposited on slide glass was developed using four kinds of powders. Then, these were transferred to lifter, and the quality of the transferred fingermark was observed. As a result of measuring the adhesive force of the lifter using the ASTM D3121-17 rolling ball tack method, the difference in adhesion between the lifters except the gelatin lifter was small. Also, it was confirmed that the quality of the transferred fingermark was not significantly related to the adhesive force of the lifter. However, if the quality of the transferred fingermark is not good when transferring to a gelatin lifter which is a lifter having a weak adhesive force, additional transfer is possible.

Development of Analysis Model and Sensitivity Analysis for High-Power Hydraulic Drifter Design (고출력 유압 드리프터 설계를 위한 해석모델 개발 및 민감도 분석)

  • Noh, Dae-Kyung;Lee, Dae-Hee;Yun, Joo-Seop;Lee, Dong-Won
    • Journal of the Korea Society for Simulation
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    • v.27 no.2
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    • pp.11-24
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    • 2018
  • The purpose of the present study is to develop an analysis model to analyze the design parameter sensitivity of a high-power drifter suitable for implementation in Korean hydraulic drills. This study aims to establish a basis for the optimization of the impact performance and stability of a high-power drifter by investigating the effects of each design parameter on the impact performance via design parameter sensitivity analysis. To begin, an analysis model of drifter dynamics is developed, and the reliability of the analysis model is verified by comparing the analysis results to the experimental results. The drifter is then redesigned for compatibility with Korean hydraulic drills. Finally, design parameter sensitivity analysis of the redesigned drifter is conducted to determine the effects of the design parameters on the impact performance, and to extract the high-sensitivity parameters. SimulationX, which is multi-physics analysis software, is used to develop the analysis model, and EasyDesign is employed for design parameter sensitivity analysis.

Analysis of Drifter's Critical Performance Factors Using Its Hydraulic Analysis Model (드리프터 유압 해석모델을 활용한 성능격차 유발 인자 접근 사례)

  • Noh, Dae-Kyung;Seo, Jaho;Park, Jin-Sun;Park, James;Jang, Joo-Sup
    • Journal of the Korea Society for Simulation
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    • v.23 no.3
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    • pp.33-40
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    • 2014
  • Drifter is equipment which is hard to localize. Performance of prototype hasn't performed well compared to product of leading companies even though advanced foreign firm's product were dead copied. This study shows cases of approaching the factor which produces performance gap through drifter hydraulic analysis model which is core component of rock drill. Progression of procedure is following. 1) Securing reliability of the analysis model by comparing impact test result with analysis result. 2) Drawing a graph which indicates performance gap between prototype and drifter of advanced foreign firm by using analysis model. 3) Approaching the factor which produces performance gap with analysing variable of the analysis model. Software used for this analysis is SimulationX.

Case of Dynamic Performance Optimization for Hydraulic Drifter (유압 드리프터의 동적성능 최적화 사례)

  • Noh, Dae-kyung;Lee, Dae-Hee;Jang, Joo-Sup;Yun, Joo-Seop;Lee, Dong-Won
    • Journal of the Korea Society for Simulation
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    • v.28 no.2
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    • pp.35-48
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    • 2019
  • Domestic hydraulic drifters till now have been developed by benchmarking products from overseas leading companies. However, they do not have excellent impact performance as they are not suitable for characteristics (large flow rate and low pressure) of Korean hydraulic drill power pack, and therefore, research on the optimum design has not made much headway. This study performs multi-objective function optimization for hydraulic drifters whose capacity has been redesigned to deal with the large flow rate, and also with the help of this function, it aims to improve impact power and reduce supply and surge pressure. A summary of the research study is as follows: First, we set goals for improving impact power, supply pressure, and surge pressure, and then perform multi-objective function optimization on them. After that, we secure the reliability of the optimized analytical model by comparing the test results of the prototype built by the optimized design with the analysis results of the analytical model. This study used SimulationX, that is the hydraulic system analysis software, and EasyDesign, which is a multi-objective function optimization program. Through this research, we have achieved the results that satisfy the goal of developing high power drifters suitable for Korean type hydraulic drills.

Study for the Actuation of Lifter by the Bi-Directional Pump and Single-Rod Cylinder (양방향펌프와 편로드실린더에 의한 리프터의 구동에 관한 연구)

  • Lee, Seong-Rae;Kim, Je-Min
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.4
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    • pp.139-145
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    • 2007
  • The motion of single-rod cylinder is typically controlled by the directional control valve. In some case, the hydraulic system should be energized by the man power and at the same time the motion of a cylinder is controlled manually. It may be confusing for a man to do two things at the same time. The solution is to make up the closed hydraulic circuit with the bi-directional pump and single-rod cylinder without using a directional control valve. In the case of single-rod cylinder, the flows at the rod side and head side are so different that several valves should be installed to make the motion of single-rod cylinder possible. The hydraulic system is composed of a bi-directional pump, a single-rod cylinder, pilot operated check valves, a check valve and a counter balance valve for the purpose of actuating the lifter. The characteristics of a suggested system are analysized mathematically and numerically.

Development of Drifter's Hydraulic System Model and Its Validation (드리프터의 유압시스템 해석모델 개발 및 신뢰성 검토)

  • Noh, D.K.;Jang, J.S.;Seo, J.H.;Kim, H.S.;Park, S.H.
    • Journal of Drive and Control
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    • v.11 no.3
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    • pp.14-21
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    • 2014
  • The goal of this study drifter is to understand the operating mechanism of a drifter and to suggest a reliable analysis model which can be used for evaluating the drifter's performance from the viewpoint of impact frequency and energy. For this, the working principle of drifter and functions of its main components were analyzed, and a simulation model was developed based on the analysis. The model was validated using experimental tests on a test-bench. A comparative study of simulation and experimental results indicated that the suggested model accurately represents the real drifter system in terms of impact frequency and impact energy per blow.

Clean Lifter Design Using Magnetic Levitation System (자기부상을 이용한 클린 리프터 설계)

  • Kim, Jong-Moon;Kang, Do-Hyun
    • Proceedings of the KIEE Conference
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    • 2005.07b
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    • pp.1171-1173
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    • 2005
  • This paper presents a clean lifter design using a magnetic levitation system. Electromagnets are used as a levitation magnet attached to the clean lifter. The lateral forces are generated by the magnets so that non-contacting bearings are implemented. The clean lifter design specifications are suggested and the overall system is described.

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Isolated Digit and Command Recognition in Car Environment (자동차 환경에서의 단독 숫자음 및 명령어 인식)

  • 양태영;신원호;김지성;안동순;이충용;윤대희;차일환
    • The Journal of the Acoustical Society of Korea
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    • v.18 no.2
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    • pp.11-17
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    • 1999
  • This paper proposes an observation probability smoothing technique for the robustness of a discrete hidden Markov(DHMM) model based speech recognizer. Also, an appropriate noise robust processing in car environment is suggested from experimental results. The noisy speech is often mislabeled during the vector quantization process. To reduce the effects of such mislabelings, the proposed technique increases the observation probability of similar codewords. For the noise robust processing in car environment, the liftering on the distance measure of feature vectors, the high pass filtering, and the spectral subtraction methods are examined. Recognition experiments on the 14-isolated words consists of the Korean digits and command words were performed. The database was recorded in a stopping car and a running car environments. The recognition rates of the baseline recognizer were 97.4% in a stopping situation and 59.1% in a running situation. Using the proposed observation probability smoothing technique, the liftering, the high pass filtering, and the spectral subtraction the recognition rates were enhanced to 98.3% in a stopping situation and to 88.6% in a running situation.

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