• 제목/요약/키워드: Stick-up

검색결과 78건 처리시간 0.027초

TDD 기법을 이용한 적층식 석탑의 동특성 추출 (Extracting Modal Parameters of a Layered Stone Pagoda Using TDD Technique)

  • 김병화;문대중;이도형
    • 한국지진공학회논문집
    • /
    • 제19권3호
    • /
    • pp.103-108
    • /
    • 2015
  • This work introduces a modal testing and analysis results of the mock-up for a layered stone pagoda. The pagoda has been horizontally excited by an impact hammer. As to the measured acceleration time responses, the first five lower mode shapes and natural frequency are extracted by the TDD technique. It is observed that the time delay of a shear wave occurs through friction surfaces. Such phenomena cannot be described by using the traditional analytical models such as a continuum cantilever beam model or a discrete shear building model. However, the time delay typically affects only the phases of the pagoda system. The frequencies of the pagoda system are not affected by such time delay. It is found in the first time that the layered stone pagoda system has a set of closely placed modes in near of natural frequency. It is believed that such modes are due to the friction characteristics in friction surfaces. Based on the stick-slip friction model, it seems that the one of the closely placed mode can be a self-excited one.

전단압전가진기를 이용한 인치웜 가진시스템의 개발 (Development of a New Inchworm Actuation System U sing Piezoelectric Shearing Actuators)

  • 이상원
    • 한국정밀공학회지
    • /
    • 제24권8호통권197호
    • /
    • pp.81-88
    • /
    • 2007
  • This paper presents the development of a new inchworm actuation system using the shearing deformation of the piezoelectric actuators. In this new actuation system, piezoelectric shearing/expanding actuators, an inertial mass and an advanced preload system are configured innovatively to generate the motion of an inertial mass. There are two modes in the new actuation system: (1) stick mode, and (2) clamp mode. In stick mode, the deformation of the piezoelectric shearing actuators drives an inertial mass by means of the friction force at their contact interface. On the other hand, in clamp mode, the piezoelectric expanding actuators provide the gripping force to an inertial mass and, as a result, eliminate its backward motion following the rapid backward deformation of the piezoelectric shearing actuators. To investigate the feasibility of the proposed new actuation system, the experimental system is built up, and the static performance evaluation and dynamic analysis are conducted. The open-loop performance of the linear motion of the proposed new actuation system is evaluated. In dynamic analysis, the mathematical model for the contact interface is established based on the LuGre friction model and the equivalent parameters are identified.

ASM 기반의 얼굴 특징 영역 추출 및 변형된 알파 블렌딩을 이용한 가상 메이크업 프로그램 (A Virtual Makeup Program Using Facial Feature Area Extraction Based on Active Shape Model and Modified Alpha Blending)

  • 구자명;조태훈
    • 한국정보통신학회논문지
    • /
    • 제14권8호
    • /
    • pp.1827-1835
    • /
    • 2010
  • 본 논문은 사용자 사진에서 ASM(Active Shape Model)을 이용하여 얼굴의 각 특징 점을 추출하고, 추출 된 특징점을 이용하여 화장할 부분의 영역을 생성 한다. 기존의 가상 메이크업 프로그램에서는 사용자가 수동적으로 몇 개의 특징 점을 정확히 선택해야 하는데서 불편함을 초래했다. 본 논문에서 제안하는 가상 메이크업 프로그램에서는 ASM을 이용하여 사용자의 입력을 필요로 하지 않는다. 자연스러운 화장 효과를 표현하기 위해서 기본적인 알파 블렌딩을 각각 화장품의 특징에 맞게 변형하여 사용자 피부색과 화장품의 색을 혼합한다. 얼굴 윤곽, 눈, 눈썹, 입술, 볼의 영역을 생성하고, Foundation, Blush, Lip Stick, Lip Liner, Eye Pencil, Eye Liner, Eye Shadow 종류의 화장을 할 수 있게 구현하였다.

고대 로마 신화에 등장한 신들의 복식 연구 (A Study on the Costume of the Gods in the Ancient Roman Myths)

  • 임상임;추미경
    • 한국의류학회지
    • /
    • 제25권5호
    • /
    • pp.945-956
    • /
    • 2001
  • The costume for gods in the Ancient Roman myth was studied by examining in the embossed-carving, sculptures, mural-painting and various documents of the period. The clothes item, hairstyle, symbol & ornaments and shoes of the gods in the Roman myths were analyzed to understand the formative process in the religious costumes, and results are as follows. First, the costumes for male gods are the same as those for ordinary men lived in ages, including toga, paludamentum, tebenna, tunica. The costumes for female gods are also the same as those for ordinary women lived in ages, including stola, palla, tunica. Second, the hairstyle of male gods is short curled-hair, twisty roll-up hair and braid long-hair due to the influence of Etrurian in the early days. Another hairstyle is appeared in form of the laurelled-crown. The hairstyle of female gods is curled long-hair, chignon style and braid roll-up hair decorated with hairband. Third, the symbol & ornaments which represent the responsible possession of male gods, are appeared in beard, a stick of the message, arrow-case, offering-dish, antlered-glass, shield, spear-handle, as the superhuman forms, such as the lightning shape. For female gods they are is appeared plastron, a stick of the message, flower. some female gods wear necklace, foot-ring, bracelet. Fourth, male gods wear shoes in forms of sandal, buskin, boots, but all female gods are in barefoot. It could be explained by the fact that a man-centered society in the ancient roman is reflected in the world of gods. As mentioned, Gods costume in Roman myths was very similar to or nothing different from the ordinary peoples in Rome. However, they used corps, sacrifices or sepcific symbols depending on the fields that they were responsible for in order to be distinguished from the ordinary people. This is the result from the peoples expression that they should keep a close relationship with Gods hoping to be protected, and rely on them under whatever circumstances.

  • PDF

체성감각계 지원이 여성노인의 보행 및 평형감각 유지에 미치는 효과 (Effect of somatosensory input on the gait ability and equilibrium sensory of elderly women)

  • 정철;박우영
    • 한국응용과학기술학회지
    • /
    • 제35권1호
    • /
    • pp.205-213
    • /
    • 2018
  • 평형능력은 보행에 영향을 미치고, 보행속도는 노인의 건강한 척도를 말해주는 기준이 된다. 이 연구의 목적은 체성감각계 지원이 여성 노인의 보행 및 평형감각에 미치는 영향을 보고자 하였다. 평소 지팡이를 사용하지 않고, 규칙적으로 운동을 하지 않으며, 이비인후과적으로 이상이 없는 노인으로 평균 연령이 75세 여성 노인 61명을 실험군 31명과 통제군 30명으로 분류하였다. 종속변인으로는 2.44m왕복걷기, 10m 일반걷기 및 빠르게 걷기, 6분 걷기를 실시하였다. 평형감각 검사로는 뉴로컴사의 EquiTest를 이용하여 분석하였다. 연구 결과 2.44m 왕복걷기와 10m 일반걷기에서는 유의한 차이가 없었으나 10m 빠르게 걷기, 6분걷기에서는 유의한 효과를 보이는 것으로 나타났다. 평형감각에서는 조건 2, 3, 4, 6에서 유의한 효과를 보이는 것으로 나타났다. 결론적으로 체성감각계 지원이 노인 여성들의 보행 및 평형유지 능력에 유의한 효과를 보이는 것으로 나타나 지팡이의 적극적 사용이 권장된다 할 수 있겠다.

무한대를 이용하는 여과평면 구성 및 하향 여과공기 거동조성과 최적집진에 관한 연구 (A Study on the Downward Filteration Movement, the Dust Collection and Filteration Plane Constitution by the use of Infinity)

  • 정동백
    • 한국대기환경학회지
    • /
    • 제11권4호
    • /
    • pp.373-375
    • /
    • 1995
  • In order to turn the Bag Filter to the Purse Filter, the past system that the adverse reason is removed, the input of synthetic materiality of dust and air is placed down, and the output is placed up has been improved so that any adverse effect shall not be raised. The form of filteration mechanism is changed from a cylinder from, and the dust and air is mixed to make the entry velocity and one person can velocity of the mixed materiality become lower by the use of infinity, and the reception of filteration mechanism has been made reasonably. The dust separated from the filteration mechanism is desceded down, snd the mixde materiality is ascended up. So, a cross point is formed, and a collision and a friction is occurred from its process, and at its result, dust is scattered to stick to a filter cloth, therefore, the loss of pressure shall ont be appeared by cause of the increase of dust-loading.

  • PDF

파랑과 속도전단에 의한 유출유의 분산 특성 (Dispersion Characteristics of Spilled Oil by Waves and Velocity Shear)

  • 설동관;류청로;김종규
    • 한국해양환경ㆍ에너지학회지
    • /
    • 제1권2호
    • /
    • pp.18-26
    • /
    • 1998
  • 본 논문은 쇄파와 속도 전단에 의해 발생하는 난류에 의해 해상에 유출된 기름이 유적으로 분해되어 해수면 하로 분산되어 가는 과정을 논하였다. 유막 분산의 역학적 메커니즘을 파악하기 위하여 두 가지 수리실험, 즉 전단발생장치와 조파수조를 이용하여 난류를 발생시켰다. 이러한 실험으로부터 혼합시간이 증가함에 따라 수면에 형성된 유막은 수십 마이크로미터에서 수백 마이크로미터의 입경을 가진 유적으로 분산되었다 뿐만 아니라 유출된 기름의 풍화정도에 따라서 상이한 분산 메커니즘을 나타내는 것을 확인할 수 있었다.

  • PDF

가스내장 히트파이프의 냉시동특성과 성능에 관한 연구 (A Study on the Chilling Start-up Characteristics and Performance of a Gas Loaded Heat Pipe)

  • 홍성은;강환국
    • 설비공학논문집
    • /
    • 제18권11호
    • /
    • pp.915-922
    • /
    • 2006
  • Considering heat pipe design principles in fabrication and operational performances, water is one of the most recommended working fluids to make mid to low tempera lure heat pipes. But the conventional water heat pipes might encounter the failure in a cold start-up operation when socked at a chilling temperature lower than the freezing point. If they are subjected to a heat supply for start-up at a temperature around $-20^{\circ}C$, the rate of the vapor flow and the corresponding heat transfer from the evaporator to the condenser is so small that the vapor keeps to stick on the surface of the chilling condenser wall, forming an ice layer, resulting in a liquid deficiency in the evaporator. This kind of problems was resolved by Kang et al. in 2004 by adopting a gas loading heat pipe technology to the conventional water heat pipes. This study was conducted to examine a chilling start-up procedure of gas loading heat pipes by investigating the behaviors of heat pipe wall temperatures. And the thermal resistance of the gas loaded heat pipe that depends on the operating temperatures and heat loads was measured and examined. Two water heat pipes were designed and fabricated for the comparison of performances, one conventional and the other loaded with $N_2$ gas. They were put on start-up test at a heat supply of 30 W after having been socked at an initial temperature around $-20^{\circ}C$. It was observed that the gas loaded one had succeeded in chilling start-up operation.

부식된 핵연료 피복관과 지지격자 사이의 프레팅 마멸 특성 (Fretting Wear Characteristics of the Corroded Fuel Cladding Tubes for Nuclear Fuel Rod against Supporting Girds)

  • 김진선;박세민;김용환;이승재;이영제
    • Tribology and Lubricants
    • /
    • 제23권3호
    • /
    • pp.130-133
    • /
    • 2007
  • Fuel cladding tubes in nuclear fuel assembly are held up by supporting grids because the tubes are long and slender. Fluid flows of high-pressure and high-temperature in the tubes cause oscillating motions between tubes and supports. This is called as FIV (flow induced vibration), which causes fretting wear in contact parts of tube and support. The fretting wear of tube and support can threaten the safety of nuclear power plant. Therefore, a research about the fretting wear characteristics of tube-support is required. The fretting wear tests were performed with supporting grids and cladding tubes, especially after corrosion treatment on tubes, in water. The tests were done using various applied loads with fixed amplitude. From the results of fretting tests, the wear amounts of tube materials can be predictable by obtaining the wear coefficient using the work rate model. Due to stick phenomena the wear depth was changed as increasing load and temperature. The maximum wear depth was decreased as increasing the water temperatures. At high temperatures there are the regions of some severe adhesion due to stick phenomena.

부식된 핵연료 피복관과 지지격자 사이의 프레팅 마멸 특성 (Fretting Wear Characteristics of the Corroded Fuel Cladding Tubes for Nuclear Fuel Rod against Supporting Girds)

  • 이영제;김진선;박세민;김용환;이승재
    • Tribology and Lubricants
    • /
    • 제24권3호
    • /
    • pp.129-132
    • /
    • 2008
  • Fuel cladding tubes in nuclear fuel assembly are held up by supporting grids because the tubes are long and slender. Fluid flows of high-pressure and high-temperature in the tubes cause oscillating motions between tubes and supports. This is called as FIV (flow induced vibration), which causes fretting wear in contact parts of tube and support. The fretting wear of tube and support can threaten the safety of nuclear power plant. Therefore, a research about the fretting wear characteristics of tube-support is required. The fretting wear tests were performed with supporting grids and cladding tubes, especially after corrosion treatment on tubes, in water. The tests were done using various applied loads with fixed amplitude. From the results of fretting tests, the wear amounts of tube materials can be predictable by obtaining the wear coefficient using the work rate model. Due to stick phenomena the wear depth was changed as increasing load and temperature. The maximum wear depth was decreased as increasing the water temperatures. At high temperatures there are the regions of some severe adhesion due to stick phenomena.