• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.97-102
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• 2008

The vibration of a vehicle, which is caused by and transmitted from the engine, has significant effect on the ride comfort and the dynamic characteristics of the engine mount system have direct influence on the vibration and noise of the vehicle. This paper examines the body shake caused by the engine excitation force on engine key on/off of a medium truck by experiment and simulation. The analysis model consists of the engine, a body including the frame, front and rear suspensions and tires. The force element between the body and the suspension is modeled as a combination of a suspension spring and a damper. The engine shake obtained from the experiment was compared with the result of the computer simulation, and by using the verified computer model, parametric study of the body shake on engine key on/off is performed with changing the stiffness of an engine mount rubber, the engine mount angle, and the position of engine mounts.

• Journal of Drive and Control
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• v.12 no.2
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• pp.27-33
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• 2015

Excavators are versatile earthmoving equipment that are used in civil engineering, hydraulic engineering, grading and landscaping, pipeline construction and mining. Effective operator training is essential to ensure safe and efficient operating of the machine. The virtual reality excavator based on simulation using conventional large size monitors is limited by the inability to provide a realistic real world training experience. We proposed a flexible observation method with a head tracking system to improve user feeling and sensation when operating a virtual reality excavator. First, an excavation simulator is designed by combining an excavator SimMechanics model and the virtual world. Second, a head mounted display (HMD) device is presented to replace the cumbersome large screens. Moreover, an Inertial Measurement Unit (IMU) sensor is mounted to the HMD for tracking the movement of the operator's head. These signals consequently change the virtual viewpoint of the virtual reality excavator. Simulation results were used to analyze the performance of the proposed system.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.42.2-42.2
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• 2009

한국천문연구원에서 개발 중인 KHz급 Satellite Laser Ranging(SLR) 시스템인 ARGO-M 의 운영시스템 중의 하나인 Interface Control System 은 현재 시각에서의 위성의 위치를 개산하여 추적마운트부에 Tracking 정보를 제공하고, 주기적으로 발사되는 레이저의 귀환 시간을 계산하여 수신광검출기 게이트를 열어야 하는 시간을 FPGA 보드에 전달하는 기능 등을 수행하게 된다. 이러한 일련의 작업은 각각 필요한 시점에 정확하게 실행되어야 하며 이를 위해 실시간 운영체계가 사용될 예정이다. 실시간 운영체계 하에서 Ranging 에 관련한 프로세스를 수행할 경우에 발생될 수 있는 문제점을 검토하기 위해서 기존에 Austria Graz SLR 관측소에서 사용하고 있는 DOS용 테스트 프로그램을 실시간 운영체계로 검토되고 있는 INtime 환경으로 이식하여 성능을 기존의 DOS 프로그램과 비교하여 보았다. Controller 역할을 담당하고 있는 FPGA 보드와의 데이터 통신의 주기성을 확인하는 시험 결과 실시간 운영체계를 사용하는 경우가 USB 사용 등 외적인 교란에 의한 영향을 적게 받는 것을 확인 할 수 있었다. 또한 500피코초 단위의 해상도를 갖는 내부 이벤트 타이머와의 연계, 레이저 발사 명령, 광검출기의 게이트 여닫기 등의 프로세스가 실시간 환경에서 문제점 없이 구현 가능함을 확인하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.623-628
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• 2016

Because the log information provides some critical clues for solving the problem of illegal system access, it is very important for a system administrator to gather and analyze the log data. In a Linux system, the syslog utility has been used to gather various kinds of log data. Unfortunately, there is a limitation that a system administrator should rely on the services only provided by the syslog utility. To overcome this limitation, this paper suggests a syslog agent that allows the system administrator to gather log information for file access that is not serviced by syslog utility. The basic concept of the suggested syslog agent is that after creating a FUSE, it stores the accessed information of the files under the directory on which FUSE has been mounted into the log file via syslog utility. To review its functional validity, a FUSE file system was implemented on Linux (Ubunt 14.04), and the log information of a file access was collected and confirmed.

• Journal of Astronomy and Space Sciences
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• v.20 no.2
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• pp.143-152
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• 2003

We constructed the photometric observation system with a small semi-automatic telescope for the systematic observations of eclipse timings of eclipsing binary stars. The system is consisted of a Paramount GT-1100s mount system, a Celestron 14 optical system, and a SBIG ST-8 camera. We developed the OBSTOOL S/W which controls the telescope and the CCD camera using the COM(Component Object Model) supported by the softwares, The Sky and MaximDL. The system performs photometric observations of a variable, comparison and check stars by moving the telescope to the chosen star separately in a similar way such as the method of photoelectric observation. We wrote pert scripts which enable a data handling pipeline for the obtained data to be classified by each of date, object and filter. And thus the images are easily preprocessed using the IRAF S/W package. Eclipse light curves of some eclipsing binary stars observed with this system are presented.

• Journal of the Korean earth science society
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• v.24 no.5
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• pp.456-466
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• 2003

We developed a remote control system for the 16" reflecting telescope at KNUO (Kongiu National University Observatory). This system is a close loop system. The electronic control part used TCS-196 of the Korea Astronomy Observatory, the mechanical part was developed directly in this research. The pointing accuracy of this system was ${\pm}$50" in the hour angle direction, ${\pm}$40" in the declination direction after mount modeling. The tracking accuracy was about 1"/min. This pilot test result means that this system is suitable for research or education of astronomical fields.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.6
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• pp.786-795
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• 2011

This paper described the characteristic of vibration in wind turbine system including gearbox housing, gear drive, blade, generator. Especially, in planetary gear set, planet gears are supported by flexible pin. So, in planet gear, to consider not only torsional movement but also lateral movement. And include housing movement, because wind turbine system is supported by mount. To find out the characteristic of vibration, take the excitation source and study campbell diagram in operating range. Results of campbell diagram, resonances are occurred at 81.2HZ, 104.7Hz by 2nd tooth passing frequency. And resonance are also occurred at 264.5HZ, 377Hz, 424.6Hz by 3th tooth passing frequency. From the result, take vibration reduced measures.

• Journal of Platform Technology
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• v.9 no.3
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• pp.70-77
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• 2021

The purpose of Serious games in immersive Metaverse platform to provide users both fun and intriguing learning experiences. We proposes a serious game for self-trainable fire evacuation drill with collaboration among avatars synchronized with multiple trainees and optionally with real-time supervising placed at different remote physical locations. The proposed system architecture is composed of wearable motion sensors and a Head Mounted Display to synchronize each user's intended motions to her/his avatar activities in a cyberspace in Metaverse environment. The proposed system provides immersive as well as inexpensive environments for easy-to-use user interface for cyber experience-based fire evacuation training system. The proposed configuration of the user-avatar interface, the collaborative learning environment, and the evaluation system on the VR serious game are expected to be applied to other serious games. The game was implemented only for the predefined fire scenario for buildings, but the platform can extend its configuration for various disaster situations that may happen to the public.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.6
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• pp.589-601
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• 2003

XLink is XML Linking Language that defines links between XML documents or XML elements. It uses XML syntax to create structures that can describe links similar to the simple unidirectional hyperlinks of HTML, as well as more sophisticated links. There exist several relationships between resources that linked by XLink. Without supports from XML Repository for these relationship management, there is a huge overhead related to the management of relationships during both application development and maintenance, since the relationships need to be hard-coded directly into the application program itself. In this paper, we propose an XLink supporting system in object repository. We describe the design and implementation of this system on top of XDOM(persistent DOMlink XML repository). To support XLink, our system offers referential relationship semantics, extended link and the expansion of DOM tree for XLink.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.292-298
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• 2009

This paper investigates the control performance of the proposed hybrid mount system for vibration isolation table. The hybrid mount system consists of an air spring as a passive device and a PZT stack actuator as an active device in series. The feasibility of the PZT stack actuator as an active actuator was examined through the simple experiments. After that, a series of numerical simulations were carried out to evaluate the control performance of the proposed hybrid mount system. The equations of motion of the table with a set of hybrid mount systems consisting of four devices are derived. The air spring is considered as a 1 spring and 1 dashpot elements, and PID control algorithm is adopted to estimate the control force. The results of the numerical simulations presents that the proposed hybrid mount system could be the promising control system for vibration isolation table.