• Journal of Korean Society of Transportation
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• v.7 no.2
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• pp.5-15
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• 1989

The Provision of a Passing lane is strongly recommended When adeguate Passing Sight distance cannot be acguired at a Section of two-lane highway. Passing lanes are usually installed at two-lane highways along the shoulder area to minimize the impact of slow-moving heavy vehicles. The design concepts and specific dimension associated with the Passing lane construction are investigated in This research. In addition a case study was made using the field study data. Currently the level of service at the case study area was analyzed to be "F" based on 1985 Highway Capacity Manual procedure. With the installation of passing lanes, the level of service was improved into "C". A computer Simulation program developed by Australian Road Research Boand was utilized to analyze the effect of passing lanes.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.815-824
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• 2013

Pneumatic exciters can be good replacements of electrodynamic, piezoelectric and hydraulic exciters owing to simple structure and large exciting force. One problem to be solved is a slow response caused by compressibility of air. Desirable frequency response characteristics of exciter are constant magnitude and zero degree phase, because users want no time delay between input signal and output force. For this reason, frequency range of pneumatic exciters is limited about 0~1 Hz. Therefore, expansion of frequency range is an important issue when designing the pneumatic exciter. In this paper, the pneumatic exciter which has same structure with active pneumatic isolator is dealt with. The dynamic characteristics are presented, and its limitation of expanding frequency range is shown based on analytical studies. Then the pneumatic exciter with dual-chamber is suggested to overcome this problem. Based on simulation study, a design method is presented.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.7
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• pp.107-114
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• 2004

This paper presents a two-time scale approach for vibration reduction of a high speed Cartesian manipulator. High speed manipulators would be subject to mechanical vibration due to high inertia forces acting on linkages. To achieve high throughput capability, such motion induced vibration would have to be damped quickly, to reduce settling time of the manipulator end-effector. This paper develops a two-time scale model fer a structurally-flexible Cartesian manipulator. Based on the two-time scale model, a composite controller consisting of a computed torque method for the slow time-scale rigid body subsystem, and a linear quadratic state-feedback regulator for the fast time-scale flexible subsystem, is designed. Simulation results show that the proposed two time-scale controller yields good performance in attenuating structural vibration arising due to excitation from inertial forces.

• IEMEK Journal of Embedded Systems and Applications
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• v.14 no.4
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• pp.165-175
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• 2019

Networks use relatively slow heartbeat mechanisms, usually in routing protocols, to detect failures when there is no hardware signaling to help out. The time to detect failures available in the existing protocols is no better than a second, which is far too long for some applications and represents a great deal of lost data at 10 Gigabit rates. We compare the convergence time of routing protocol applying Bidirectional Forwarding Detection (BFD) protocol in wired mesh network topology. This paper suggests the combinations of protocols improving fail-over performance. Through the performance analysis, we contribute to reduce convergence time when system is fail-over.

• Journal of the Semiconductor & Display Technology
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• v.16 no.2
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• pp.75-78
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• 2017

We reports improved monitoring performance of Self plasma-optical emission spectroscopy (SP-OES) by augmenting a by-pass tube to a conventional straight (or single) tube type self plasma reactor. SP-OES has been used as a tool for the monitoring of plasma chemistry indirectly in plasma process system. The benefits of SP-OES are low cost and easy installation, but some semiconductor industries who adopted commercialized SP-OES product experiencing less sensitivity and slow sensor response. OH out-gas chemistry monitoring was performed to have a direct comparison of a conventional single type tube and a by-pass type tube, and fluid dynamic simulation on the improved hardware design was also followed. It is observed faster pumping out of OH from the chamber in the by-pass type SP-OES.

• International journal of advanced smart convergence
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• v.10 no.2
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• pp.175-186
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• 2021

We have studied the speed regulation of the permanent magnet synchronous motor (PMSM) servo system in this paper. To optimize the PMSM servo system's speed-control performance with disturbances, a non-linear speed-control technique using a back-propagation neural network (BP-NN) algorithm forthe controller design of the PMSM speed loop is introduced. To solve the slow convergence speed and easy to fall into the local minimum problem of BP-NN, we develope an improved BP-NN control algorithm by limiting the range of neural network outputs of the proportional coefficient Kp, integral coefficient Ki of the controller, and add adaptive gain factor β, that is the internal gain correction ratio. Compared with the conventional PI control method, our improved BP-NN control algorithm makes the settling time faster without static error, overshoot or oscillation. Simulation comparisons have been made for our improved BP-NN control method and the conventional PI control method to verify the proposed method's effectiveness.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.85-90
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• 2022

In this paper, an asynchronous nonvolatile memory module using a self-diagnosis function was designed. For the system to work, a lot of data must be input/output, and memory that can be stored is required. The volatile memory is fast, but data is erased without power, and the nonvolatile memory is slow, but data can be stored semi-permanently without power. The non-volatile static random-access memory is designed to solve these memory problems. However, the non-volatile static random-access memory is weak external noise or electrical shock, data can be some error. To solve these data errors, self-diagnosis algorithms were applied to non-volatile static random-access memory using error correction code, cyclic redundancy check 32 and data check sum to increase the reliability and accuracy of data retention. In addition, the possibility of application to an asynchronous non-volatile storage system requiring reliability was suggested.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.157-158
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• 2023

Building Information Modeling (BIM) design has been mandatory in Korea since 2016, and it has been gradually expanding in the industry, with a slow attempt to apply it in remodeling constructions. This is because Korea is facing a situation where many buildings are over 30 years old and require remodeling or reconstruction. The remodeling industry is also a growing market, as it saves construction time and cost compared to reconstruction. BIM is an ideal technology element for a competitive remodeling construction, as remodeling constructions face a complicated construction process from the start, including demolition, maintenance, and reinforcement to save the change process. However, there are still limitations in applying BIM to remodeling constructions, due to considerations of the existing building and the complicated requests of the inhabitants. BIM still has technical and environmental limitations for general use. In this study, I analyzed BIM application cases from existing studies and suggest what improvement points should be strengthened.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.211-212
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• 2023

Building Information Modeling (BIM) design has been mandatory in Korea since 2016, and it has been gradually expanding in the industry, with a slow attempt to apply it in remodeling constructions. This is because Korea is facing a situation where many buildings are over 30 years old and require remodeling or reconstruction. The remodeling industry is also a growing market, as it saves construction time and cost compared to reconstruction. BIM is an ideal technology element for a competitive remodeling construction, as remodeling constructions face a complicated construction process from the start, including demolition, maintenance, and reinforcement to save the change process. However, there are still limitations in applying BIM to remodeling constructions, due to considerations of the existing building and the complicated requests of the inhabitants. BIM still has technical and environmental limitations for general use. In this study, I analyzed BIM application cases from existing studies and suggest what improvement points should be strengthened.

• Aerospace Engineering and Technology
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• v.8 no.1
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• pp.49-57
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• 2009

The camera electronics in the KOMPSAT-3 payload provides the several control clocks in order to move the charges, which are converted from the light in the pixel, in the vertical and horizontal direction. Generally, the control clocks depend on the CCD internal design in the system. The KOMPSAT-3 payload uses the CCD controlled by 3-phase vertical clocks and 4-phase timing. The camera generates the various clocks such as the vertical clocks, the horizontal clocks, the summing clocks, the reset clocks and so on. The vertical clocks are deeply related to the camera performance and synchronized with satellite scan-rate even though they are relatively slow. Also, it gives the horizontal clocks without distortion under the very fast pixel-rate. This paper shows the design and simulation of the CCD clocks driver for the KOMPSAT-3 payload.