• 항공우주정책ㆍ법학회지
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• 제22권1호
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• pp.55-74
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• 2007

When the People's Republic of China destroyed one of its own defunct meteorological satellites, the Fengyun-1C, at an altitude of some 865 km above the earth's surface, the PRC was accused of initiating, or at the very least risking an(other) arms race in outer space also. The test also gave rise to a few legal questions as to the permissibility of this test, and the broader permissibility of using space for military and other weapon-touting activities, Whilst the test cannot be considered to constitute a direct threat to international peace and security so as to invoke relevant legal principles and consequences in terms of the UN Charter for example, it highlights the importance of such clauses in international space law as requiring international cooperation and consultation, due regard for the interests of all other countries both on earth and in outer space, and the further development of general regimes of registration and space debris-prevention. From that perspective, the PRC violated international outer space law not so much by the test itself but by the accompanying lack of information, consultation and due regard for other states', and indeed mankind's, interests.

• 항공우주정책ㆍ법학회지
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• 제spc호
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• pp.181-199
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• 2007

When the People's Republic of China destroyed one of its own defunct meteorological satellites, the Fengyun-1C, at an altitude of some 865 km above the earth's surface, the PRC was accused of initiating, or at the very least risking an(other) arms race in outer space also. The test also gave rise to a few legal questions as to the permissibility of this test, and the broader permissibility of using space for military and other weapon-touting activities, Whilst the test cannot be considered to constitute a direct threat to international peace and security so as to invoke relevant legal principles and consequences in terms of the UN Charter for example, it highlights the importance of such clauses in international space law as requiring international cooperation and consultation, due regard for the interests of all other countries both on earth and in outer space, and the further development of general regimes of registration and space debris-prevention. From that perspective, the PRC violated international outer space law not so much by the test itself but by the accompanying lack of information, consultation and due regard for other states', and indeed mankind's, interests.

• 항공우주정책ㆍ법학회지
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• 제27권2호
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• pp.211-241
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• 2012

유럽연합(European Union: EU)이 2012년 6월 유엔의 우주의평화적이용위원회(COPUOS) 제 55차 회기에서 공식 제기한 우주활동의 국제 행동규범안(Draft International Code of Conduct for Outer Space Activities)은 그간 우주에서의 국가 활동 규범에 대한 미비한 요소들을 제시한 내용으로서 국제사회의 관심을 끌기에 충분한 내용이다. 현재 우주에서의 미비한 질서는 군비경쟁 금지, 우주쓰레기 경감 등을 통한 우주의 안전과 안보를 위한 지침, 그리고 우주활동의 정보를 참여 국가 간 교환하는 것이라고 할 수 있는 바, EU의 상기 제안은 여사한 문제들에 대한 행동 강령을 정한 것으로서 주목되는 내용이다. 2008년 말부터 시작된 EU의 제안 활동은 그간 일부 우주활동 국가들, 특히 미국과의 비공식 접촉을 통하여 접촉대상국들의 의견도 반영한 가운데 2013년 채택을 목표로 하는 자발적 이행 규범으로서 강제력을 가지고 있지는 않지만 미국은 우주에서의 군축 관련 규범 제정의 필요성에 탄력을 제공하는 계기가 될 가능성에 우려하는 가운데 현재는 방관하고 있는 입장으로 보인다. 이러한 미국의 입장은 우주에서 전략적 우위를 점하고 있다는 자국의 이익이 군축에 관한 규범의 제정으로 손상될 수 있다는 판단을 근거로 하고 있다. 이에 따라 미국은 유엔 총회에서 우주에서의 군비경쟁 방지(PAROS)에 관한 결의에 반대하고 군축회의(Conference on Disarmament: CD)에서 오랫동안 논의되어 왔던 우주에서의 군축을 촉구하는 논의의 장을 마련하는 것에 반대하여 왔다. 중국과 러시아는 2008년 우주에서의 군축에 관한 PPWT (Treaty on Prevention of the Placement of Weapons in Outer Space and of the Threat or Use of Force against Outer Space Objects)채택을 제안하였는 바, EU의 제안은 자신들이 제안한 PPWT의 추력을 저상시키는 내용이 되기 때문에 불편한 심정으로서 역시 소극적인 입장이다. 한편, 미국이 상기 입장의 연장선 상에서 PPWT에 반대 입장을 취하는 것은 이해하기 어렵지 않다. EU의 행동규범안은 주요 우주대국의 군사전략적 측면에서의 이해관계 때문에 그 장래가 명확치 않으나 우주쓰레기의 경감을 위하여 노력하고 우주활동의 정보를 상호교환하면서 우주에서의 안전과 안보를 보장을 통하여 가능한 우주의 평화적 이용과 탐사라는 기본 명제를 극대화 시키는 효과를 가져오는 것으로서 매우 바람직한 조치로 간주된다. 단, 동 규범안은 참여 국가들간의 협조와 연락업무를 수행하기 위하여 상설기구를 설치하도록 되어있지만 이는 기존 조직인 유엔외기권사무소(UN Office for Outer Space Affairs)가 담당하도록 할 경우 효율과 경제를 도모할 수 있을 것이다. 동 규범안에 대한 추후 구체 협상 시 여사한 내용도 논의될 것으로 보지만 EU의 우주활동의 안전과 안보에 관한 조치는 환경문제에서와 같이 국제사회를 이끌어가는 또 하나의 의미있는 기여로 평가받아야 한다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.303-304
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• 2002

This paper presents theoretical analysis of the NRRO(the non-repeatable run-out) for a ball bearing with geometric imperfection. This imperfection contains ball size error, ball waviness, outer race waviness and inner race waviness. The 3D dynamic analysis of a ball bearing using the Newton-Raphson method is performed to calculate the displacement of shaft center. The radial and axial NRRO are simulated, and preload and clearance effects are investigated. Preload and clearance have significant effects on radial and axial NRRO of for miniature ball bearings.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.369-374
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• 2002

This paper presents theoretical analysis of the NRRO(non-repeatable run-out) for a ball bearing with geometric imperfection. The 3DOF dynamic analysis of a ball bearing using the Newton-Raphson method is performed to calculate the displacement of shaft center. Frequency and magnitude characteristics of radial and axial vibrations are investigated. The ball form errors of the ball, the inner race, and the outer race in a HDD spindle ball bearing are precisely measured. NRRO of a ball bearing is analyzed by using the measured waviness data. It is concluded that dominant components of radial vibrations are ${\Large}f_c\;and\;2{\Larg}f_b{\pm}{\Large}f_c$, and dominant component of axial vibrations is $2{\Large}f_b$. These are generated by the size error and the second waviness of the balls.

• 한국소음진동공학회논문집
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• 제14권12호
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• pp.1287-1294
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• 2004

Hub bearings not only sustain the body of a cat, but permit wheels to rotate freely. Excessive radial or axial load and many other reasons can cause defects to be created and grown in each component. Therefore, nitration and noise from unwanted defects in outer-race, inner-race or ball elements of a Hub bearing are what we want to detect as early as possible. How early we can detect the faults has to do with how the detection algorithm finds the fault information from measured signal. Fortunately, the bearing signal has Periodic impulse train. This information allows us to find the faults regardless how much noise contaminates the signal. This paper shows the basic signal processing idea and experimental results that demonstrate how good the method is.

• Journal of Advanced Marine Engineering and Technology
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• 제12권2호
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• pp.35-45
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• 1988

In this paper an experimental review of condition monitoring method using time domain vibration signals and statically measured wave forms of a multi-components damaged ball bearing is presented first time. Many investigators studied already about vibration characteristics of a single point damaged ball bearing but they did not make efforts to verify vibration phenomena of a multi-components damaged one. Even in case of a tripple components damaged (i.e, outer race, inner race and rolling element) one, the high frequency resonance technique (HERT) and the displacement time domain technique can be also used for its fault detection. According to experimental results undertaken a static displacement measuring method, the defect locations of components can be proposed confidently with simple calculation of the rotating angles of each component.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.341.1-341
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• 2002

This paper presents theoretical analysis of the NRRO(the non-repeatable run-out) for a ball bearing with geometric imperfection. The 3DOF dynamic analysis of a ball bearing using the Runge-Kutta method is performed to calculate the displacement of shaft center. Frequency and magnitude characteristics of radial and axial vibrations are investigated. The ball form errors of the ball, the inner race, and the outer race in a HDD spindle ball bearing are precisely measured. (omitted)

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.593-596
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• 2004

Hub bearings not only sustain the body of a car, but permit wheels to rotate freely. Excessive radial or axial load and many other reasons can cause defects to be created and grown in each component. Therefore, vibration and noise from unwanted defects in outer-race, inner-race or ball elements of a Hub bearing are what we want to detect as early as possible. How early we can detect the faults has to do with how the detection algorithm finds the fault information from measured signal. Fortunately, the bearing signal has periodic impulse train. This information allows us to find the faults regardless how much noise contaminates the signal. This paper shows the basic signal processing idea and experimental results that demonstrate how good the method is.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 춘계학술대회 논문집
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• pp.222-228
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• 1999

The two-microphone sound-intensity technique has been used for the detection of defects in radially loaded ball bearings. The difference in the sound-intensity levels measured for bearings with no defect and for those with intentionally introduced defects of different sizes in their elements under various operating conditions of loads and speeds is demonstrated. A change in the intensity frequency spectrum because of the defects is observed. The results show that the detectability of an outer-race defect is much better than that of on inner-race or ball defect. It is difficult to detect defects at lower speeds. Sound-pressure measurements were also performed fur comparison, and it is shown that the detectability of defects by sound-intensity measurements is better than that by sound-pressure measurements.