• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1533-1539
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• 2000

In this paper, we propose a design method using Taguchi method and a neural network. Using this method, we can design a dual-stage actuator having the required tracking/focusing properties in real time. Also, as an application of this method, a proposed dual-stage pick-up actuator having the required properties was designed. The seek time of this designed actuator is less than 13 msec by a time optimal technique. Simulation results show that this method can potentially be implemented in all the dual-stage actuators.

• 대한기계학회논문집B
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• 제24권8호
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• pp.1056-1061
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• 2000

Particles existing in a hard disk drive are known as a major source of TA(thermal asperity). Researchers have investigated how particles induce the TA phenomena, but have not verified yet the reason why and how particles are generated in a HDD. The objective of this study is to investigate why and how particles are generated, and in what condition, the largest number of particles is generated. The number of particles generated in a HDD was measured over the landing zone after various rest times of slider and during various motions and positions of slider. It is found that the large number of particles was generated when the HDD was turned on after a long rest time of slider and that a few of particles were continuously generated when the slider flied over the disk surface. It is thought that the number of particles generated in a HDD was related to the rest time of slider because the rest time of slider increased stiction, and that there were intermittent contacts between the slider and the disk surface when the slider flied over the disk surface.

• 제어로봇시스템학회논문지
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• 제9권1호
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• pp.10-21
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• 2003

During seek operation in disk drives, the recording head is moved toward desired track by seek servo controller and then is settled onto the center of the desired track by settling servo controller. If the head speed at the start of settling servo control is not slow, it may produce overshoot relative to the center of track and thus extend the settling time. The degradation in settling performance will be more severe as the track width becomes smaller for higher density of data storage. We design a new settling servo controller for minimizing settling time based on the pole-zero cancellation. In order to cancel slow poles in settling response, we apply discrete pulse signals to the system in addition to the state feedback control. For exact pole-zero cancellation, we consider the dynamics of power amplifier used for actuator current regulation and the effects of delay in control action. In addition, we present system parameter identification algerian for the robustness of our controller to system parameter variation. In order to demonstrate the practical use of our controller, we present experimental results obtained by using a commercially available disk drive.

• 산업경영시스템학회지
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• 제13권21호
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• pp.111-117
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• 1990

This paper treats the problem to schedule for train with low transit priority so as to maximizing the number that can be sent during given time without interfering with the fixed schedule for train with high transit priority in a track. We transform the this problem into Time-Expanded Network without traverse time through application of Ford-Fulkerson Model, develop a TENET GENerator(TENETGEN) and obtain the data of TENET using developed TENETGEN. Finally, we seek the optimal solution to these data with Dinic's Maximal-Flow Algorithm and examine the availability of our procedures in personal computer.

• 전자공학회논문지S
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• 제34S권8호
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• pp.65-73
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• 1997

The effects of time-sampling on linear output regulation problem is ivestigated. It is found that the solvability of linear output regulation problem is generally not robust with respect to time-sampling although the solvability of that for single inut and single output linear systems and the solvability of linear robust output regulation problem are preserved under time-sampling. The resutls imply that one needs to seek a better approximate sampled-data output regulator.

• 비교문화연구
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• 제34권
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• pp.43-68
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• 2014

This writing, focused on by Tarkovsky and by Song, Il-gon, examines moments of sage which is what Eliade described as 'hierophanic time'. These productions, which can be seen as movies that seek after the truth, show important paradoxical ideas and expressions in those moments. This is because symbolic messages from unrealistic and out of ordinary images are specifically shown. If they had to be compared, through the film by Tarkovsky, the technical civilization of contemporary society in an apocalyptic view is criticized and saved, or the prophetic will to not give up the desire for salvation is shown. In the process, the short shots which forces to show hierophanic time not only diversely visualized the author's ideological self-consciousness towards the conversion of the new world, but it also fulfills the metahistorical meanings mentioned by Eliade. However, in the film by Song, Il-gon, the realistic personal sufferings of three women is specifically shown first in extreme. They overcome their unsolvable problems through mysterious rituals and belief in miracles. In the scenes that include hierophanic time, there are many cases that cover Christian faith and the meaning of salvation. In other words, we can say that hierophanic time in , are related to conviction which led to moments of miracles in order to overcome reality. Therefore, even though there is a difference in the way authors use hierophanic time, the scenes that show it in the two movies display individuality of mythical imaginations disclosed by Eliade. This is because the general hope for reproduction, or meaningful symbols related to the ideal conversion of affairs are revealed.

• 제어로봇시스템학회논문지
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• 제12권6호
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• pp.614-620
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• 2006

Today the automobile has been changed from a mechanical system to an electronic control system fly the development of the electronic technology. In the automobile body, most of these electronic control devices are networked and managed fully by the CAN protocol. But, when a network system is overloaded, unexpected transmission delay for relative low priority objects occurs due to the static priority definition of the CAN protocol. To resolve this problem, this paper proposes a dynamic precedence queue mechanism that creates a queue for the low priority object and its relevant objects to be transmitted, which becomes urgent in an overloaded network system to keep the maximum allowable time delay. For the generated queue, the highest priority is assigned to transmit the queued objects within the shortest time. The mechanism is implemented in the logical link layer of CAN, which does not require any modification of the old CAN hardware. Effectiveness of the proposed mechanism is verified by the real experiments with an automobile network system.

• Bulletin of the Korean Chemical Society
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• 제10권4호
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• pp.372-374
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• 1989

The new viscosity theory is applied to the abnormal behavior of the viscosity near the critical point. This theory suggests that the viscosity is equal to the product of the absolute pressure(kinetic pressure + internal pressure) and the collision time. We can find this abnormal behavior to be due to the large collision time near the critical point. The agreements between theoriticals and experimentals of the critical enhancement are satisfactory.

• 한국환경보건학회지
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• 제35권2호
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• pp.116-123
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• 2009

Laboratory scale experiments were conducted to investigate the removal characteristics of nitrogen and phosphorus by the variation of aeration time in four sequencing batch reactors (SBRs). In R1 which has the shortest aeration time as 1 h, MLVSS concentration in reactor decreased by the wash-out of biomass because of the poor sedimentation. The TOC removal efficiencies were almost similar in 3 reactors except R1. At the low aeration time as 1 h, the nitrification was severely inhibited by the deficiency of oxygen. ${NH_4}^+$-N removal efficiency was decreased by the decrease of aeration time. At the aeration time over 2 h, the phosphorus removal efficiency was not affected by the variation of aeration time. The nitrification was inhibited but the phosphorus release and uptake was not inhibited by the decrease of low aeration time. Therefore, we can see that the phosphorus removal microorganisms are superior to nitrification microorganisms in oxygen utilization.

• 한국정보과학회논문지:시스템및이론
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• 제28권12호
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• pp.660-673
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• 2001

주문형 비디오 서버에서 동시에 서비스 될 수 있는 사용자의 수는 서버의 단위 시간당 처리량에 의해 결정되는데, 서버의 처리량은 대부분 디스크의 처리량에 의해 제약을 받는다. 따라서, 디스크의 처리량은 서버 설계에 있어서 매우 중요한 요소가 되며, 대부분의 서버의 경우, 이를 높이기 위해 디스크 배열을 이용한다. 본 논문에서는 디스크 배열에서 디스크들의 탐색 시간을 줄여 전반적으로 디스크의 처리량을 증대시킬 수 있는 효율적인 주기적 요철 묶음 기법을 제안한다. 제안된 기법에서는 디스크 내 인접 영역에 저장된 데이터를 요청하는 주기적 요청들을 하나의 묶음으로 만들고, 각 묶음들이 동일 디스크를 순차적으로 접근할 수 있도록 좌대칭 혹은 우대칭 형식으로 정렬하여 각 디스크에서 요청들이 겪게되는 탐색 시간을 줄인다. 이는 단일 데이터 스트림에 의해 요구되는 디스크 대역폭을 줄일 수 있으므로, 서버는 주어진 시스템 자원 하에서 보다 많은 사용자들을 서비스 할 수 있다. 모의 실험 결과, 제안된 기법은 기존의 기법들에 비해 보다 많은 사용자들을 서비스 할 수 있음이 확인되었다. 일반적인 192KB의 블록 크기를 이용할 경우, 일반 디스크 배열에 비해 평균 20%의 사용자 대기 시간 감소와 평균 8%의 동시 이용자 증가를 보였다. 또한, 본 논문에서는 비디오 스트림들에 대한 사용자 선호도 변화에 맞추어 묶음들을 재구성하는 적응 기법을 제시한다.