• Tunnel and Underground Space
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• v.30 no.6
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• pp.591-602
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• 2020

Several alternative rock-cutting concepts, which are modified from the conventional ones, have been developed lately. Of the concepts, undercutting is one of the latest technologies. In this study, as a fundamental study on the undercutting technique, the rock-cutting mechanism and important parameters of the undercutting were introduced. This study built up cutting test system for evaluating the cutting performance of an actuated undercutting disc cutter (ADC), and carried out a series of cutting tests under different cutting parameters of ADC. The characteristics of cutter forces obtained from ADC rock-cutting tests were analyzed. The both average and peak values of the three directional cutter forces were linearly increased with the increases of linear velocity, penetration depth in vertical direction and eccentricity of ADC.

• Journal of IKEEE
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• v.26 no.3
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• pp.515-519
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• 2022

In this paper, we propose the development of a high-sensitivity entry-level nuclide analysis module. The proposed measurement sensor module consists of an electronic driving circuit for nuclide analysis resolution, prototype production with nuclide analysis function, and GUI development applied to prototypes. The electronic part driving circuit for nuclide analysis resolution is divided into nuclide analysis resolution process by the electronic part driving circuit block diagram, MCU circuit design used for radiation measurement, and PC program design for Spectrum acquisition. Prototyping with nuclide analysis function is made by adding a 128×128 pixel OLED display, three buttons for operation, a Li-ion battery, and a USB-C type port for charging the battery. The GUI development department applied to the prototype develops the screen composition such as the current time, elapsed measurement time, total count, and nuclide Spectrum. To evaluate the performance of the proposed measurement sensor module, an expert witness test was conducted. As a result of the test, it was confirmed that the calculated result by applying the resolution formula to the Spectrum (FWHM@662keV) obtained using the Cs-137 standard source in the nuclide analysis device had a resolution of 17.77%. Therefore, it was confirmed that the nuclide analysis resolution method proposed in this paper produces improved performance while being cheaper than the existing commercial nuclide analysis module.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.3
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• pp.157-165
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• 2000

A small hydraulic winch system with an automatic tension control unit was designed to improve the work efficiency of coastal small vessels and the dynamic response characteristics of the winch system operated in the open loop condition was investigated. The inlet and the outlet pressures in hydraulic motor, the torque and the rotating speed of winch drum were measured as a function of time, and the behaviour in autotension mode for stepped load changes was analyzed. The results obtained are summarized as follows : 1. The developed winch system for coastal small vessels will result in better fishing with improved efficiency and lower manpower consumption by remote control of winch system. 2. The rotating delay times of winch drum for on/off operations of solenoid valve were 0.09 see at CW mode and 0.04 sec at CCW mode, respectively. After the solenoid valve was controlled, response characteristics were unstable slightly but showed good tracking behaviour over short time. 3. The driving torque of winch system in autotension mode was kept almost constant of 55.9 kgf·m, and 11.1 then the rotating speed of winch drum was kept almost constant of 5.1 rpm in the larger torque than 55.9 kgf·m and 11.1 rpm in the lower torque than that. 4. The 5% settling times in the transient response characteristics of autotension mode under rapid increasing and decreasing conditions of load were 0.12 sec and 0.2 sec, respectively, and then the rotating speeds were 11 rpm and 5.3 rpm, respectively. 5. The tracking behaviour of torque and rotating speed by remote control operation were stable within 0.23 sec at CW mode and 0.37 sec at CCW mode, respectively.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1042-1043
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• 2015

미니트램(Mini-Tram)은 승하차 시간 동안 정거장에서의 무선급전 방식에 의한 급속충전(약, 2분 30초 이내)을 통해 에너지를 공급받으며, 운행 시 차상에 설치된 에너지저장 매체(LIC: Lithium-Ion Capacitor)로부터 전기에너지를 공급받아서 운행된다. 차량에 요구되는 에너지 소모량을 분석하고 이에 맞춰서 저장 매체의 직-병렬 구성 및 전력 변환 장치(Regulator 및 DC-DC 컨버터 등)를 설계하는 것은 전기 구동 차량인 미니트램의 설계에서 매우 중요한 부분이다. 본 논문에서는 미니트램 시스템을 개발하는 과정에서 수행된 에너지공급시스템의 사양 선정을 위한 에너지 소모량 예측과 더불어 이와 관련된 주행저항 및 주행성능 분석에 대해서 다룬다.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.172.1-172.1
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• 2012

위성은 발사 후 임무수행을 위하여 필수적인 자세정보를 획득해야 한다. 별 추적기는 궤도상에서 별의 위치를 파악하여 상대적인 위성의 위치를 확인하는 데에 사용하는 감지기이다. 별 추적기는 태양, 지구, 달 등의 광원으로부터 오는 빛을 차단해 주는 시야각제한기(baffle), 광학계소자(CCD) 및 렌즈, 열제어소자(cooler) 그리고 전원 및 전자박스 등으로 구성된다. 위성은 발사 전 조립시험 기간 동안 전자파, 진동, 열/진공 등의 환경시험 통하여 수차례의 성능 유무를 확인한다. 이 환경시험 전과 후에는 위성의 모든 전장품의 기능시험을 수행하여, 각 전장품의 환경영향 유무를 판별한다. 특히 벌 추적기 관련시험으로, 광학계 성능 검증을 위한 광학적 자극시험과 전자박스의 구동확인을 위한 전자박스 점검시험이 있다. 본 논문에서는 지상에서 수행한 별 추적기의 기능시험 결과를 분석하여 건정성 동향을 분석하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.58-61
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• 2010

In this paper, we research the method for HDD I/O Performance improvement by Filter Driver &NAND FLASH Memory. We analyze the effect of the operation of the Device Driver & NAND FLASH Memory and propose the method for the HDD I/O Performance improvement.

• The Journal of Korean Institute of Next Generation Computing
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• v.15 no.3
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• pp.31-39
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• 2019

Virtualization technology is one of the technologies that have been attracting attention as cloud computing spreads recently. When a system is constructed using virtualization technology, mutiple operation systems can be operated in a single host operating system, thereby facilitating efficient management of computing resources. As more and more operating systems are running on the hypervisor, it is important to measure the overall performance of the virtualization system and this is becoming an important technology. In this paper, we analyze the main functions of the existing profiling tools to measure the performance of the virtualization system, and measure and classify the profiling coverage that the monitoring tools can perform for events that may occur in the virtualization system. In addition, we have studied a framework that enables performance measurement by loading appropriate profiling tools into the guest system when performance measurement is required for the virtualization system according to the information received from the remote system performing the monitoring.

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.5
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• pp.436-443
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• 2013

This paper presents design methods of a fuzzy controller and an operator model for a wire-driven heavy material lifting system helping human workers. The wire-driven heavy material lifting system is a kind of human-assistive systems in which a human is involved in the control loop. Thus, human's control characteristics and requirement of reducing worker's force to lift a heavy material are considered in the design process of the proposed fuzzy controller. An automatic weight measurement algorithm during the early stage of lifting is also introduced. Finally, the effectiveness and performance of the proposed system are proved by experiments.

• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.3
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• pp.53-60
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• 2003

A test stand was developed to measure static performance of a reciprocating engine on the ground, related to the small aircraft being developed by KARI. The test stand consists of an apparatus to install and operate a pusher-type propulsion system and a data acquisition system to process many performance parameters including engine torque and propeller thrust as well as monitoring of the engine operations. First, the performance data from the basic operation tests were compared with the original engine data so the capacity of the test stand was verified. Engine performance tests were carried out with various test conditions through three stages, and it was measured and analyzed that the manifold pressure, the torque, and the back pressure of the engine, and the static thrust of the propeller.

• Journal of Power System Engineering
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• v.15 no.1
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• pp.11-17
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• 2011

본 연구는 라디칼 착화(Radical Ignition이하 RI) 기술을 적용한 부실직분식 CNG(Compressed Natural Gas) 엔진의 구동특성에 관한 것이다. 실험엔진은 단기통 디젤엔진을 개조하여 사용하였으며, 이는 부실식 디젤엔진처럼 연소실이 주실과 부실로 나누어져 있다. 부실에 분사된 CNG는 스파크플러그로 점화하며, 부실로 부터의 연소가스가 주실 희박 혼합기를 시켜 구동하는 엔진이다. RI 기술은 연소속도를 향상시킬 수 있다. 본 연구는 주로 저부하 RI-CNG 엔진의 성능을 연구하였다. 연료분사기간은 9 ms, 공기과잉률은 1.0, 1.2, 1.4로 하였다. 연료분사시기는 엔진의 배가밸브가 닫히는 ATDC $20^{\circ}CA$ 부터 $120^{\circ}CA$ 사이로, $20^{\circ}CA$ 간격으로 지각시켜 가며 실험하였다. 본 연구는 연료분사시기 및 공기과잉률이 연소최고압력 ($P_{max}$), 연소최고압력시기(${\Theta}_{pmax}$), 도시평균유효압력(IMEP), 사이클 변동계수($COV_{imep}$), 연소속도에 미치는 양향 등을 구하고 분석하였다.