• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 V
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• pp.2669-2672
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• 2003

This paper describes a new method of discrimination between the normal disc and the rewritable one. The conventional method of disc discrimination, using Focus error signal, has a heavy fluctuations. To achieve an accurate discrimination, in this paper, the sum of side beam［1］signal is used for that. A new approach is expected to improve the performance of disc discrimination as well as to reduce the signal variation almost by 50％. Techniques in this paper are applicable to the all types of optical disc player, such as CD (compact disc), VCD(Video-CD) and DVD (digital versatile disc) and any other optical disc players.

• 정보저장시스템학회논문집
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• 제10권1호
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• pp.27-31
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• 2014

Optical Archive system consists of cartridge, drive and transfer robot. Transfer robot moves disc in cartridge to drive that reads data of disc. Distance between disc in cartridge and transfer robot very short, about 4mm. When disc projects, there is a danger of collision. Collision can cause breakage of disc and breakdown of system. To prevent collision of disc and transfer robot, projection of disc should be detected. In this paper, we proposed error monitoring method of projecting disc in archive data storage using camera. Proposed algorithm is evaluated by experiments with archive system.

• 센서학회지
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• 제8권3호
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• pp.211-218
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• 1999

This paper describes the application of a coupled finite element-boundary element method (FE-BEM) to obtain the steady-state response of a piezoelectric transducer. The particular structure considered is a PZT4 disc-typed projector. The projector is three-dimensionally simulated to transduce applied electric charge on axial surfaces of the piezoelectric disc to acoustic pressure in air or in water. The directivity pattern of the acoustic field formed from the projected sound pressure is also simulated. And the displacement of the disc caused by the externally applied electric charge is shown in temporal motion. The coupled FE-BE method is described in detail.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.580-585
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• 2003

Korean high speed train (KHST) has adopted a combined electric/ mechanic (friction) braking system. Electric brakes are consist of rheostatic brake, regenerative brake and eddy current brake and mechanical brakes are composed of disc brake, wheel disc brake and tread brake. In this paper, we introduce the braking performance test and the measuring method of mechanical brake. And disc brake performance has been reviewed by the experimental method. The on-line test of KHST has been carried out up to 260 km/h and proved that the disc braking capacity of KHST is sufficient.

• 전자공학회논문지S
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• 제35S권5호
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• pp.27-34
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• 1998

This paper is on the discrete model reduction method over disc-type analytic domains. We define hankel singular value over the disc that is mapped by standard bilinear mapping. And the generalized singular perturbation approximation and the direct truncation are generalized to GSPA and DT over a disc. Furthermore, it is shown that the reduced order model over a smaller domaing has a smaller .inf.-norm error bound. And the poposed reduction method is used to obtain the regional pole placement property.

• 센서학회지
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• 제13권3호
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• pp.244-251
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• 2004

In general, the braking system of high speed train has an important role for the safety of the train. To stop safely the train at its pre-decided position, it is necessary to combine properly the various brakes. Korean high speed train (HSR 350x) has adopted a combined electric and mechanic (friction) braking system. Electric brakes are consist of rheostatic brake, regenerative brake and eddy current brake and mechanical brakes are composed of disc brake, wheel disc brake and tread brake. In this paper, the measuring method that can take a measurement of the braking forces for disc brake and wheel disc brake has been suggested and we have verified that this method is valid through on-line test of HSR 350x.

• 한국기계가공학회지
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• 제6권3호
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• pp.38-46
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• 2007

Weight reduction for an automobile component has been sought to achieve fuel efficiency and energy conservation. In response to this trend, a new disc-brake called the circumferential friction disc-brake is suggested. This paper compares the mechanical performances of a conventional disc-brake and a suggested disc-brake, under the dynamic braking condition. The thermoelastic instability is considered to simulate the test condition. Furthermore, the metamodel using kriging interpolation method is introduced to obtain the optimum design of a suggested circumferential friction disc-brake. The design results obtained by the kriging method are compared with those obtained by the ANSYS.

• 정보저장시스템학회논문집
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• 제1권1호
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• pp.53-57
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• 2005

In order to measure signal quality of optical disc such as CD or DVD, jitter is used traditionally. The signal attained from a disc by optical pick-up is processed by analog circuits. And then, binary signal can be obtained by using proper silcer. After the signal is changed into binary format, jitter is calculated as a time difference between the binary signal and the reference time. Jitter is used to express the signal quality. In this paper, a new method that is able to offer more precise measurement of the signal quality fur high density optical disc than the jitter is proposed. We named it LPSNR (Level Peak Signal to Noise Ratio). The relationship between bER (bit error rate) and LPSNR is shown in the paper.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.43-46
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• 1991

Nd-Fe-B Permanent Magnet, which is recently more used, has some advantages in comparison with other permanent magnet. However, for the Nd-Fe-B has higher RTC(reversible temperature coefficient), property of the Nd-Fe-B magnet is changed by temperature rise. In this paper temperature rise of a disc type motor is calculated using a heat source network method.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.150-155
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• 2004

The base material of optical disc is the amorphous polymer, polycarbonate. So crack growth on the rotating optical disc could happen by the static centrifugal force. This phenomenon is called static fatigue. Today's CD-R disc drive is being operated over 10,000 RPM. This is increasing the possibility of the disc fracture when operating. In this reason, new method to measure the static fatigue threshold quality and the way to calculate the threshold J-integral value and the safe crack length of the optical disc are studied. Finally the environmental effect to optical disc is also studied in this paper.