• Journal of the Korean Society for Precision Engineering
• /
• v.27 no.8
• /
• pp.28-34
• /
• 2010

Railway wheel and axle is the most critical components in railway system. A wheel and axle failure can cause a derailment with its attendant loss of life and property. The service conditions of railway vehicles have become severe in recent years due to a general increase in operating speeds. Therefore, more precise evaluate of wheelset strength and safety has been desired. Fracture mechanics characteristics such as dynamic fracture toughness, fatigue threshold and charpy impact energy with respect to the tread, plate, disc hole of wheel and the surface of press fitted axle are evaluated. This paper describes the difference of fracture toughness, fatigue crack growth and fatigue threshold at the locations of wheel and axle. The results show that the dynamic fracture toughness, $K_{ID}$, is obviously lower than static fracture toughness, $K_{IC}$ and the fracture mechanics characteristics are difference to the location of wheel tread and hole.

• Transactions on Electrical and Electronic Materials
• /
• v.15 no.3
• /
• pp.113-116
• /
• 2014

Power transformer insulation oil is critical to the useful life of the transformer. Although mineral base insulation oil is the most common type of transformer insulation oil in use, environmental and safety concerns has encouraged the development of biodegradable alternatives. Today, $Envirotemp^{(R)}\;FR3^{TM}$ is in commercial use and this study is aimed at ascertaining the possibility of applying the oil in Malaysia power transformers. A sample of $Envirotemp^{(R)}\;FR3^{TM}$ was tested to measure and compare the technical (including electrical, chemical and physical) properties of the oil according to Malaysian standards. The study found that the oil sample had better qualities, such as higher dielectric strength, lower dissipation factor, higher flash and fire points, higher moisture absorption capability, and less dissolved gases composition amongst others. However, it was also ascertained that further development in this area could be hindered due to Malaysia's lack of standards for biodegradable oil.

• KIEAE Journal
• /
• v.13 no.1
• /
• pp.151-157
• /
• 2013

Since high-rise building construction sites are usually located in crowded city areas, sufficient spaces for the inventories of key materials are rarely available. This spatial constraints have been one of the critical challenge that may cause productivity loss and increasing costs of the high-rise building construction projects. The proper material inventory management is certaing a key to the success of high-rise building construction projects as it handles difficulty of securing material stock yards, changes in demands, uncertain delivery time through integrating the construction schedules and actively responding to the key materials attributes. In this light, this research analyzes the latest inventory model, (Q,r) model, in accordance with the high rise building characteristics. This research suggests an optimal inventory management of re-bar considering various demands and lead times. The case study is also presented with regard to the re-bar inventory management.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.25 no.4
• /
• pp.39-50
• /
• 1998

The object of this study was to examine and analyze the environmental deterioration of three major trails and around peak area of Moaksan Provincial park in 1996. Trails are mostly made up at ridgeline and the slope of them is gentle. Mean trail width is 3.6m, and total length of branch trails is 982m in survey area. The environmental deterioration is derived from trail extension. Maximum eroded depth and cross-section area loss are 89cm and 14,050cm2 respectively, and gully erosion type appears at many sites. The environmental deterioration of trails is very heavy at the sections from Khui to Moaksan peak and from Moakchong to ascent part around the peak. The entire width, branch trail, maximum depth, cross-sectional area loss and surface roughness, as the indexes of trail conditions, are significantly greater at the more heavily used trails. Amount of erosion is influenced by eroded depth, longitudinal slope, runoff influence and entire width in descending order as well as the amount of use. Safety and protection facilities on the trail such as stone and soil stairs, rope handrail, stone channel and soil ditch work are built, but they are very deficient. Bared lands about 4,900m2 and fill slopes are caused and formed by recreation activities and constructions around peak area. It is required to carry the recess system and to conserve and rehabilitate the destroyed trail sites and bare fill slopes as soon as possible, before the environmental deterioration becomes critical because of increased used amount in consequence of construction of recreation parks.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.8 no.4
• /
• pp.239-246
• /
• 2004

The fixed ends beam is analyzed by the s d 0 f system with the rigid-plastic model. And the safety criteria of the fixed ends beam to the Impulsive loads are established with the peak-load ratio to the static collapse load and impulse ratio to the ideal impulse producing the critical displacement. It is shown that the impulse and the peak-load of the impulsive loads are the important factors for the damage of the structures. It is also shown that the damage curves with the peak-load and impulse ratio are useful method to estimate the damage of the structures due to the emphasis on the equivalent dynamic loads rather than the equivalent static loads in the process of deriving the curve.

• Proceedings of the Korean Information Science Society Conference
• /
• 2007.10d
• /
• pp.440-445
• /
• 2007

본 논문은 USN을 이용하여 최근 식중독의 원인을 체계적으로 제거하기 위해 식품 위해 요소 중점관리인 HACCP(Hazard Analysis and Critical Control Point) 안전관리시스템을 개발하였다. HACCP 안전관리시스템은 센서 네트워크, 패킷포워더, 관리서버로 구성된다. 각 주방기기에 부착한 센서 노드는 자율 네트워크를 구성하여 측정한 센싱 데이터를 관리서버로 송신하고, 관리서버는 수신한 데이터를 분석하여 사용자에게 HACCP 관련 서비스를 제공한다. 본 논문에서는 센서 노드용 펌웨어를 개발하고, 응용 소프트웨어를 개발하였다. 기존 HACCP 시스템에서 문제시되었던 통신망 구축 문제, 유지보수 문제를 본 논문에서 해결하였다. HACCP 안전관리시스템은 자율적인 모니터링과 CCP 기록을 자동적으로 작성하여 식품위해요소 관리에서 신뢰성 향상과 장애 발생 시 신속한 조치가 가능하게 할 수 있는 시스템이다. 유비쿼터스의 핵심 기술인 센서 네트워크 기술을 이용하여 기존 HACCP 시스템의 문제점은 개선할 수 있었다.

• International Journal of Railway
• /
• v.7 no.2
• /
• pp.57-63
• /
• 2014

This paper presents the optimization of suspension characteristics under the condition of curved track railway vehicles. Reducing lateral acceleration on curved track is an issue for high-speed railway vehicles. In terms of curved track running environments, reducing the lateral vibration of railway vehicles is critical to safety and curving performance. The properties of lateral damping and stiffness of both primary and secondary suspension show effect on wheel-set, bogie and car-body. Analysis for reducing the lateral vibration of rail vehicles with respect to the characteristics of both primary and secondary suspension has been developed using ADAMS/Rail. Response Surface Method has been chosen for the purpose of verifying correlation effects among design parameters. Also, this paper suggests the method for designing optimal suspension of railway vehicles on curved track. The optimization result indicates decrement of lateral acceleration on wheel-set by 3% and bogie by 1% on curved track. Finally, this paper comes to the conclusion that suspension system of railway vehicle (KTX I) is properly designed when regarding lateral vibration of railway vehicle on diverse curved track condition.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2018.10a
• /
• pp.286-287
• /
• 2018

As the number of single-person households is increasing in Korea, the demand for emergency support networks for the elderly and women is also growing. To meet the need, systemic solutions, such as a wide distribution of cell phones with embedded motion sensors that can alert the first responders or police in case of health or safety crisis, are regarded as critical issues. This paper introduces a design which registers the user's motions to process emergency reports via a mobile app running in the background. The method offers an affordable solution to reporting emergencies taking place both indoors and outdoors as it does not require an addition of hardware but only simple hand gestures.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.614-615
• /
• 2007

There are roughly a hundred types of cables in power plants. The distribution of circuits in a nuclear plant is comprised of 20% instrument cables, 61% control cables, 13% AC power cables, 1% DC power cables, and 5% communication lines. In the nuclear power plant, medium voltage cables are generally included in the scope of systems reviewed for safety and are included in a plant's maintenance program. Medium voltage cables provide power to many critical components in plants, including feed water pumps, circulating water pumps, and condensate pumps. Among these cables, high temperature sections of cables feeding electrical power to the circulating water pump and the condenser extraction pump were found. The evaluation for these cables is performed to find the maximum allowable current and temperature. The result shows that the load current flowed about 85% of the allowable current ampacity, and the temperature of conductor at full load current did not exceed the limited temperature. Therefore, existing cables for circulating water pump and condenser extraction pump system are going to be used during design life.

• Mass Spectrometry Letters
• /
• v.12 no.3
• /
• pp.85-92
• /
• 2021

The therapeutic antibody drug market has experienced explosive growth as mAbs become the main therapeutic modality for a variety of diseases. Characterization of glycosylation that directly affects the efficacy and safety of therapeutic monoclonal antibodies (mAbs) is critical for therapeutics development, bioprocess system optimization, lot release, and comparability evaluation. The LC/MS approach has been widely used to structurally characterize mAbs, and recently attempts have been made to obtain comprehensive information on the primary structure and post-translational modifications (PTMs) of mAbs through intact protein analysis. In this study, we performed state-of-the-art LC/MS based intact protein analysis to readily identify and characterize glycoforms of various mAbs. Different glycoforms of mAbs produced in different expression cell lines including CHO, SP2/0 and HEK cells were monitored and compared. In addition, the comparability of protein molecular weight, glycoform pattern, and relative abundances of glycoforms between the commercialized trastuzumab biosimilar and the original product was determined in detail using the given platform. Intact mAb analysis allowed us to gain insight into the overall mAb structure, including the complexity and diversity of glycosylation. Furthermore, our analytical platform with high reproducibility is expected to be widely used for biopharmaceutical characterization required at all stages of drug development and manufacturing.