• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.1
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• pp.182-187
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• 2015

In the three-phase power system, when any one-phase or two-phases is open-phase, the unbalanced current flows and the single-phase power supplies to three-phase loads. Specially, motor coil and transformer coil receive over-current. As a result, great damage as well as electrical fire can occur to the power system. In order to improve these problems, this paper proposes that an open-phase detection device is designed by a new algorithm using electric potential difference between the resultant voltage of neutral point and ground, and a control circuit topology of open-phase protector is composed of highly efficient semiconductor devices. It improves response speed and reliability. The control algorithm circuit also operates the cut-off of a conventional residual current protective device (RCD) which flows an enforced leakage current to ground wire at open-phase accident. Furthermore, time delay circuit is added to prevent the incapable operation of open-phase protector about instantaneous open-phase not open-phase fault. The time delay circuit improves more reliability.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.5
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• pp.447-454
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• 2011

This paper reports a filtered velocity feedback(FVF) controller, which is an alternative to direct velocity feedback(DVFB) controller. The instability problems due to high frequency response under DVFB can be alleviated by the suggested FVF controller. The FVF controller is designed to filter out the unstable high frequency response. The FVF controller and the dynamics of clamped beams under forces and moments are first formulated. The effects of the design parameters(cut-off frequency, gain, and damping ratio) on the stability and the performance are then investigated. The cut-off frequency should be selected not to affect the system stability. The magnitude of the open loop transfer function(OLTF) at the cut-off frequency should be small. As increasing the gain of the FVF controller, the magnitude of the OLTF is increased, so that the closed loop response can be reduced more. The enhancement of the OLTF at the cut-off frequency is reduced but the phase behavior around the cut-off frequency is distorted, as the damping ratio is increased. The control performance is finally estimated for the clamped beam. More than 10 dB reductions in velocity response can be achieved at the modal frequencies from the first to eighth modes.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.264-270
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• 2011

This paper reports a filtered velocity feedback (FVF) controller, which is an alternative to direct velocity feedback (DVFB) controller. The instability problems due to high frequency response under DVFB can be alleviated by the suggested FVF controller. The FVF controller is designed to filter out the unstable high frequency response. The FVF controller and the dynamics of clamped beams under forces and moments are first formulated The effects of the design parameters (cut-off frequency, gain, and damping ratio) on the stability and the performance are then investigated. The cut-off frequency should be selected not to affect the system stability. The magnitude of the open loop transfer function (OLTF) at the cut-off frequency should be small. As increasing the gain of the FVF controller, the magnitude of the OLTF is increased, so that the closed loop response can be reduced more. The enhancement of the OLTF at the cut-off frequency is reduced but the phase behavior around the cut-off frequency is distorted, as the damping ratio is increased The control performance is finally estimated for the clamped beam. More than 10dB reductions in velocity response can be achieved at the modal frequencies from the first to eighth modes.

• Korean Chemical Engineering Research
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• v.58 no.2
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• pp.190-196
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• 2020

The step to obtain a process dynamic model through process experiments is very important because it needs times and expenditures. Step response method is one of the standard methods to have long been used for understanding process dynamics, obtaining dynamical models and designing control systems. For the step response, it is usually required to measure process output for a step input change in the open-loop manner. Its disadvantage criticized is the long open-loop operation. For this, a method based on the time-optimal control technique to minimize the test time for obtaining the step response has been recently presented. However, the method requires iterative computations for the minimization of test times. Here, a method where iterative computations are not required is proposed. Simulation results are presented to show that test times to obtain step responses are reduced considerably and an autotuning method based on the proposed method is compared with the relay feedback autotuning method accepted widely for the autotuning of controllers.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.3
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• pp.68-76
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• 2020

In a series of recent launch tests, North Korea has been improving the firepower of its missiles that can target South Korea. North Korea's missiles and submarines are capable of threatening targets in South Korea and are likely faster and more covert than the systems previously seen in North Korea. The advanced threats require that ROK Navy should not only detect them earlier than ever but also response quicker than ever. In addition to increasing threats, the number of young man that can be enlisted for military service has been dramatically decreasing. To deal with these difficulty, ROK navy has been making various efforts to acquire a SMART warship having enhanced defense capability with fewer human resources. For quick response time with fewer operators, ROK Navy should improve the efficiency of systems and control tower mounted on the ship by promoting the Ship System Integration. Total Ship Computing Environment (TSCE) is a method of providing single computing environment for all ship systems. Though several years have passed since the first proposal of TSCE, limited information has been provided and domestic research on the TSCE is still in its infancy. In this paper, we apply TSCE with open architecture (OA) to solve the problems that ROK Navy is facing in order to meet the requirements for the SMART ship. We first review the level of Ship System Integration of both domestic and foreign ships. Then, based on analyses of integration demands for SMART warship, we apply real time OA to design architecture for TSCE from functional view and physical view. Simulation result shows that the proposed architecture has faster response time than the response time of the existing architecture and satisfies its design requirements.

• Spatial Information Research
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• v.22 no.5
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• pp.87-98
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• 2014

Google Maps have changed the response time of Web-GIS using AJAX technologies. In addition, Google released the Open API named Google Maps API(Application Programming Interface) and it lead to the big paradigm on the Open API, where the SDK(Software Development Kit) and ASP(Application Service Provider) had ruled at the related map market. In short, the Open API has been paradigm-shifting for the web mapping. After this, government, many companies and open source foundations have guided Web-GIS market's growth through releasing the relevant Open APIs. So many comparative analysis on web-mapping API carried out by many researches. However there were no researches that can be applied to our current domestic environments. This paper investigates components of web-mapping API. Then we compare how many components supported and enumerate features for each of those APIs. Finally this paper presents direction of future development of Web Mapping API.

• Journal of Chest Surgery
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• v.18 no.4
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• pp.835-839
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• 1985

Spontaneous pneumothorax is the sudden collapse of a lung usually caused by air leaking from a sub-visceral pleural bleb. Response to closed thoracotomy, needle aspiration and simple observation is usually prompt and effective. But in some cases, these are unsuccessful and open thoracotomy is indicated. Author reviewed 37 cases of open thoracotomy in spontaneous pneumothorax experienced in the Dept. of Thoracic and Cardiovascular Surgery, Pusan National University Hospital, since Jan., 1980 to Dec., 1984. The results were as follows: 1. The causes of spontaneous pneumothorax: 73.0% was primary, 27.0% was secondary origin. 2. The most frequent age group of the patient: Between 11 and 30 years old. 3. All of te patient were male. 4. The side of open thoracotomy: 58.8% was right side, 8.8% was both side. 5. The most common indication of open thoracotomy; Persistent air leakage. 6. The most frequent sites of bleb or bullae: A-P segment in the L.U.L. and apical segment in the R.U.L.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.439-440
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• 2012

New analysis methods complement classical approaches in the vehicle NVH development by reducing and accelerating iteration steps to obtain a target sound. Therefore, tools are required that allow an integrative approach of sound engineering and structural analysis and enable a precise simulation and modification based on measured data. The Response Modification Analysis (RMA) is such a hybrid solution, which provides indications of relevant transfer paths taking into account the sensitivity of response channels to modifications of reference channels.

• Journal of Korea Technology Innovation Society
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• v.15 no.1
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• pp.1-27
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• 2012

Under the open innovation paradigm, it is needed to establish an appropriate strategic planning tool which can take both internal and external resources and capabilities into account. In response, this paper suggests the open roadmap to systematically and usefully implement open innovation. The open roadmap deals with both inbound and outbound open innovation activities. Moreover, in the inbound and outbound open innovation, six types of the open roadmap are proposed in terms of sources of innovation. The proposed open roadmap is applied to a case of open innovation in the P&G corporation for examining its usefulness and validation. It is expected that the open roadmap provides fruitful information when open innovation is done.

• Asian Journal of Innovation and Policy
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• v.9 no.2
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• pp.106-132
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• 2020

This study intends to add a factor to the discussion on the sectoral systems of innovation through Korea's response to the COVID-19 pandemic. The Korean approach is summarized as follows: the first response centers on technology and innovation. These include the development of diagnostic test methods and accurate test kits, first in the world, the use of ICT technology in epidemiological investigations, the technical response in the field, and the competitive edge in the development of medicine and vaccines that were behind the developed countries. The second response is an aggressive effort implemented just after the Chinese announcement, before the domestic outbreak; the third response is the open policy that induces voluntary participation of all subjects and people by opening all information. More important is the leadership at the national level shown in the past Korean experience and most advanced countries. National leadership must be the missing factor.