• Proceedings of the KSR Conference
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• 2004.06a
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• pp.1415-1419
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• 2004

It is essential to evaluate harmonic characteristics of high speed train using power electronics equipment such as converter-driven motor drives, battery chargers and auxiliary power supplies. The purpose of this study is to measure and analyze harmonics characteristics of korea high speed train prototype. This paper presents result of harmonics measurement and analysis of harmonics characteristics in terms of loading, speed and operation mode.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.105-117
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• 2003

The purpose of this research aimed at performing the easy design. and also the easy on-the-job application or the maintenance interval determination methodology by presenting the determining model or the optimizing maintenance interval in TBM for the preventive maintenance or facility TBM(time-based maintenance) as the preventive maintenance requires the adequate determination or the maintenance interval. The maintenance interval or TBM shall be applied differently for the each interval such as He patrol inspection, maintenance, overhaul inspection. exchange. And it is based on the composition level of equipment. The already informed theories or interval determination methodology for the patrol inspection. repair. and overhaul inspection are difficult for adopting because or the several restriction problems in applying the maintenance schemes as the theory So, the model for determining the optimizing exchange interval or part, maintenance interval of auxiliary machine, unit equipment etc. was presented to apply in the maintenance easily and appropriately.

• Journal of Drive and Control
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• v.15 no.3
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• pp.29-35
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• 2018

This paper presents the design of attachments for dual arms of disaster responding heavy machine. The heavy machine handles a variety of tasks such as cutting, shredding, picking and moving in unstructured environment. Despite the need for rapid response, the heavy machine has difficulty in repeatedly replacing the attachment depending on the task. Thus, we propose a method to solve this physical and functional contradiction relation by using TRIZ separation principles. Above all, the existing equipment and the required working scenarios were surveyed and summarized in order to separate the attachments functionally for right-handed, left-handed and two-handed operation. Then, we proposed the design directions and conceptual design as following: multi function type attachment A, for precise operation and various operations; grab type attachment B, for grasping irregular objects and auxiliary device for both arms to handle bulky objects.

• IE interfaces
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• v.12 no.1
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• pp.32-42
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• 1999

This paper proposes and implementation procedure for an automatic assembly system from a manual assembly and an evaluation method of implemented several automatic system alternatives using an AHP (Analytic Hierarchy Process) in a small-sized motor. First, the current product is redesigned for DFA (Design For Assembly) and assembly automation of motor, and then it is decided mechanisms of moving, magazining, feeding, composing of each part using main joining equipment and auxiliary equipment. Following the decided mechanism, the necessary assembly machines are selected or designed considering objectives and assembly conditions. Finally, the layout alternatives are completed for the automatic assembly system. According to the evaluation criteria which are established in advance, the automatic system alternatives are analyzed using AHP.

• Journal of Information Processing Systems
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• v.16 no.1
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• pp.30-41
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• 2020

Lines and textures are natural properties of the surface of natural objects, and their images can be sparsely represented in suitable frames such as wavelets, curvelets and wave atoms. Based on characteristics that the curvelets framework is good at expressing the line feature and wavesat is good at representing texture features, we propose a model for the weighted sparsity constraints of the two frames. Furtherly, a multi-step iterative fast algorithm for solving the model is also proposed based on the split Bergman method. By introducing auxiliary variables and the Bergman distance, the original problem is transformed into an iterative solution of two simple sub-problems, which greatly reduces the computational complexity. Experiments using standard images show that the split-based Bergman iterative algorithm in hybrid domain defeats the traditional Wavelets framework or curvelets framework both in terms of timeliness and recovery accuracy, which demonstrates the validity of the model and algorithm in this paper.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.333-336
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• 2009

the equipment increase switching frequency in order to achieve small size, a low noise, and light weight. however, the power switches have high power losses and switching stresses as the switching frequency is increased. In order to solve like this problem point from the present paper it proposed Intese Pulse Light of the half bridge methods which apply the start current circuit which applies the auxiliary equipment. Simulation and experimental result it leads and it brings is more qualitative there is 20% improvement and it confirmed that a possibility of measuring to the patient.

• Journal of the Society of Naval Architects of Korea
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• v.59 no.4
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• pp.200-206
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• 2022

This study is to develop database by an experimental method for the development of condition based maintenance for auxiliary equipment in marine engine systems. Existing ships have been performing regular maintenance, so the actual measurement data development is very incomplete. Therefore, it is best to develop a database on land tests. In this paper, a database developed by an experimental method is presented. First, failure case analysis and reliability analysis were performed to select a failure mode. For the failure simulation test, a test bed for land testing was developed. The failure simulation test was performed based on the failure simulation scenario in which the failure simulation test plan was defined. A 1.5TB failure simulation database has been developed, and it is expected to serve as a basis for ship failure diagnosis and prediction algorithm model development.

• Journal of Environmental Impact Assessment
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• v.11 no.2
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• pp.67-77
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• 2002

Air traffic increased 12% annually in Korea since 1988 after the Olympics, this rate is two times than the rate of the world average. In order to accommodate fast growing aviation demand, Incheon International Airport is operated at Yongjong Island since March, 2001. The Incheon airport project will continue till 2020. After the final phase in 2020, Incheon International Airport will handle 100 million passengers, 530,000 flights and 7 million tons of cargo annually. In this study, air pollution from aircraft and other sources are calculated and assessed in Incheon International Airport area by EDMS(Emission and Dispersion Modeling System), which is a combined emission and dispersion model for airport. EDMS could also be considered power plant, incinerator and aircraft support equipment such as ground support equipment, aerospace ground equipment, auxiliary power units. And EDMS is recommended as preferred model for air quality assessment of the airport area by U.S. EP A. The result of this study shows that NOx emission from aircraft and support utility is estimated as 27,000 - 35,000 ton/yr and Namdong-Gu area in Incheon city is affected as 30-60 ppb by the NOx emission from these sources in 2020, the final phase of Incheon international airport construction.

• Nuclear Engineering and Technology
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• v.53 no.9
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• pp.3068-3084
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• 2021

Investigations of large commercial aircraft impact effect on nuclear power plant (NPP) buildings have been drawing extensive attentions, particularly after the 9/11 event, and this paper aims to experimentally assess the damage and vibrations of NPP buildings subjected to aircraft crash. In present Part I, two shots of reduce-scaled model test of aircraft impacting on NPP building were carried out. Firstly, the 1:15 aircraft model (weighs 135 kg) and RC NPP model (weighs about 70 t) are designed and prepared. Then, based on the large rocket sled loading test platform, the aircraft models were accelerated to impact perpendicularly on the two sides of NPP model, i.e., containment and auxiliary buildings, with a velocity of about 170 m/s. The strain-time histories of rebars within the impact area and acceleration-time histories of each floor of NPP model are derived from the pre-arranged twenty-one strain gauges and twenty tri-axial accelerometers, and the whole impact processes were recorded by three high-speed cameras. The local penetration and perforation failure modes occurred respectively in the collision scenarios of containment and auxiliary buildings, and some suggestions for the NPP design are given. The maximum acceleration in the 1:15 scaled tests is 1785.73 g, and thus the corresponding maximum resultant acceleration in a prototype impact might be about 119 g, which poses a potential threat to the nuclear equipment. Furthermore, it was found that the nonlinear decrease of vibrations along the height was well reflected by the variations of both the maximum resultant vibrations and Cumulative Absolute Velocity (CAV). The present experimental work on the damage and dynamic responses of NPP structure under aircraft impact is firstly presented, which could provide a benchmark basis for further safety assessments of prototype NPP structure as well as inner systems and components against aircraft crash.

• Journal of Drive and Control
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• v.12 no.2
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• pp.21-26
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• 2015

In order to design a swash plate type pump for electro-hydrostatic actuators the performance of the hydrostatic piston shoe bearings in the low speed range needs to be examined, since the pump operates frequently at low speeds, compensating for position control errors as a control element. As a common practice, piston shoes are equipped with inner rings as an auxiliary element to enhance their tribological performance. In this paper, the effects of the inner rings of the piston shoes on the frictional loss and leakage flow rate were investigated, where three piston shoe models, with different inner ring shapes and different inlet orifice sizes, were integrated. The test results showed that a large inner ring and small inlet orifice were advantageous for reducing both the frictional loss and leakage flow rate; this could also be confirmed by computational analyses.