• Proceedings of the KSR Conference
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• 2010.06a
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• pp.984-988
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• 2010

In Korea, the next generation high-speed train, whose target is maximum speed of 400km/h and operating speed of 370km/h, has been developed since 2007. In this paper, the safety of the next generation high-speed train is compared UIC 518OR under the malfunctioning situation of the suspension system. The bogie of the next generation high-speed train has two suspensions. Two different vehicle models of the next generation high-speed train are created by using VAMPIRE and ADAMS/Rail, which are specialized to design railway vehicle. And Those models are showed same dynamic properties. First of all, the sensitivity analysis of ModelCenter is performed using model of VAMPIRE. One suspension element which has significant effects on the safety are selected by result of the sensitivity analysis. And then, the dynamic analysis when the suspension element is broken is performed using ADAMS/Rail. The 30km track between Pungsegyo and Biryong tunnel in Gyeongbu High-speed Line was used at the dynamic analysis. The estimated value is found by using the normal method of UIC 518OR. The estimated values on the normal/fault state and the limit values of UIC 518OR are compared. Finally, the safety of the next generation high-speed train is verified.

• International Journal of Precision Engineering and Manufacturing
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• v.1 no.2
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• pp.5-13
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• 2000

Most networks for automation are tuned to an expected traffic condition ar their design stage. During their actual operations, however, the networks experience considerable changes in traffic from time to time. These traffic changes caused by common events like machine failure and production schedule change may adversely affect th network performance and, in turn , the performance of the connected devices. This paper presents experimental results for performance management of a Profibus-FMS network. The performance management aims to maintain a uniform level of network performance at all stations under changing network traffic. The performance management algorithm monitors the performance of individual network stations and commands the stations to change their timer values in order to have comparable performance at all stations. In order to determine the amount of timer change, the algorithm employs a set of fuzzy rules. The algorithm has been evaluated on a Profibus network.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1765-1768
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• 1996

It is well known that the degradation transformer oil is mainly effected to the failure of transformer. In this paper it is discussed the characteristics of the degradation sensor checking transformer oil condition in live line. The degadation sensor composed with base ring, electrodes and porous ceramic passed through the transformer oil and checked the transformer oil condition with sensor's leakage current. It is important to minimize the leakage current of base ring and connection parts. To investigate the leakage current of base ring and connection parts it is examined the characteristics of V-T-I and DC 2 KV and other examinations. It is verified that ionized transformer caused by the expansion of oil temperature increase in the leakage current of porous ceramic sensor. It is certificated that the leakage current of other parts of porous ceramic is very small (about 2 %) than the porous ceramic and it is confirmed that the leakage current in porous ceramic is changed sensitively according to the new oil(NO) and and the degradation oil(DO).

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.61 no.1
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• pp.41-46
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• 2012

Electrolytic power capacitors have been widely used in power conversion system such as inverter or UPS because of characteristics of large capacitance, high-voltage and low-cost. The electrolytic capacitor, which is most of the time affected by the aging effect, plays a very important role for the power-electronics system quality and reliability. Therefore it is important to diagnosis monitoring the condition of an electrolytic capacitor in real-time to predict the failure. In this paper, the on-line remote diagnosis monitoring system for UPS DC link electrolytic capacitors using low-cost single-chip zigbee communication modules is developed. To estimate the health status of the capacitor, the equivalent series resistor(ESR) of the component has to be determined. The capacitor ESR is estimated by using RMS computation using BPF modeling of DC link ripple voltage/current. Zigbee-based hardware experimental results show that the proposed remote capacitor diagnosis monitoring system can be applied to UPS successfully.

• Steel and Composite Structures
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• v.26 no.5
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• pp.621-634
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• 2018

Flush end-plate (FEP) beam-to-column joints are commonly used for gravity load resisting parts in steel multi-storey buildings. However, in seismic resisting structures FEP joints should also provide rotation capacity consistent with the global structural displacements. The current version of EN1993-1-8 recommends a criterion aiming at controlling the thickness of the end-plate in order to avoid brittle failure of the connection, which has been developed for monotonic loading conditions assuming elastic-perfectly plastic behaviour of the connection's components in line with the theory of the component method. Hence, contrary to the design philosophy of the hierarchy of resistances implemented in EN1998-1, the over strength and the hardening of the plastic components are not directly accounted for. In light of these considerations, this paper describes and discusses the results obtained from parametric finite element simulations aiming at investigating the moment-rotation response of FEP joints under cyclic actions. The influence of bolt diameter, thickness of end-plate, number of bolt rows and shape of beam profile on the joint response is discussed and design requirements are proposed to enhance the ductility of the joints.

• Journal of mucopolysaccharidosis and rare diseases
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• v.2 no.1
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• pp.23-26
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• 2016

Mucopolysaccharidosis (MPS) I is a rare, progressive and multisystemic disease with insidious initial signs and symptoms, and making an early diagnosis can be a challenge for the first-line general medical practitioner. We report a 6-month-old girl who was brought to our well baby clinic for regular immunization with the manifestations of lumbar gibbus, hirsutism, large Mongolian spots over back and buttock, and mild bilateral legs spasticity noticed by the general pediatrician, and then newly diagnosed with MPS I after referral to the geneticist in time. Her surgical history included inguinal hernia repair at 1 month old, $CO_2$ laser supraglottoplasty for laryngomalacia and tracheostomy due to chronic respiratory failure with ventilator dependence at 2 months old. Understanding and identification of the early signs and symptoms of this disease have the potential to early diagnosis and timely appropriate treatment, which could contribute to a better clinical outcome.

• Current Photovoltaic Research
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• v.2 no.2
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• pp.63-68
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• 2014

In recent years, discoloration defects, called as snail trail, have been observed at many crystalline photovoltaic modules after a period of time ranging from several months to several years after initial installation. It has been reported that this phenomenon doesn't impact on the performance of photovoltaic modules, but it can be detected through simple visual inspection. The origin and detailed mechanism for the formation have not been identified. In this study, non-destructive analysis by Raman spectroscopy has been carried out to investigate the origin of this phenomenon. In parallel, destructive analysis by scanning electron microscopt and transmission electron microscopy was also performed in order to confirm the results from non-destructive method. Through the extensive analysis, it was found that the main cause for discoloration is the formations of $Ag_2CO_3$ and $AgC_2H_3O_2$. Detailed mechanism for the formation of these particles was indentified through systematic studies.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.279-280
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• 1998

A new algorithm is developed that can reduce the metal artifact on CT caused by pedicle screws. Metal artifact has been recognized as a major problem in precise reading of CT images. In particular, spine surgeons have been bothered with the artifact appearing on CT taken after pedicle screw insertion. To reduce the artifact, our new algorithm first finds the center line from CT images, and then overlays an exact size screw image on the CT. The exact screw is obtained from an actual design specifications of screw, and the CT images are processed to maximize bone margins while minimizing screw images through adjusting the window width and level. 실험 결과 단순한 Window W/L 조절로는 해결되지 않는군요. This algorithm provides spine surgeons with more accurate CT images and thus better interpretation of CT to ascertain the success or failure of pedicle screw insertion.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.2
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• pp.149-157
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• 2015

Ball and roller bearings are commonly used machine elements for supporting rotating motion about shafts in simple devices including bicycles, in-line skates, and electric motors, as well as in complex machines. Heat is generated by the friction in the bearings, which causes the temperature inside the bearing to increase. If the heat is not appropriately removed from the bearing, elevated temperatures may give rise to premature failure. It is, therefore, important to be able to calculate the temperature in the bearings due to friction.Here, we describe a method to estimate the frictional torque in bearings using an empirical formula developed using a method based on bearing analysis tool and the measured frictional torque in a spindle system. Thermal analysis of the spindle system including the bearings was achieved using the finite element method (FEM), and the bearing temperature was compared with measured data to verify the empirical formula.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.1
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• pp.23-32
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• 2002

The introduction of hybrid and exploitation of heterosis has played a vital role in Indian sericulture industry, which clearly depicts a quantum jump in silk production during the last four decades. Since, the introduction of heterosis, progress in silkworm breeding has depended on success or failure in identifying better combiners. Systematic procedures developed have enabled the breeders to identify the best combiners by combining ability test, line ${\TIMES}$ tester analysis or $D^2$ analysis for maximum expression of heterosis. The level of heterosis expressed in the crossbreed population is determined by the interaction between genotype and prevailing environmental factors. Except some of the pre and post cocoon parameters, heterosis is invariably higher in single crosses compared to three-way and double crosses. However, during hot and humid season, when rearing of F1 bivoltine hybrid is unsuccessful at field level and indigenous races results in very low and poor quality yield, three-way and double crosses can play an important role as an intermediary technology. The objective of this article is to review briefly the concept and causes of heterosis, utilization of different forms of heterosis in silk production and its significance in silkworm, Bombyx mori breeding.