• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.3
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• pp.519-527
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• 1997

AISI 316 steel has been used extensively for heater and boiler tube of the structural plants such as power, chemical and petroleum plants under severe operating conditions. Usually, material degradation due to microcrack or precipitation of carbides and segregation of impurity elements, is occured by damage accumulated for long-term service at high temperature in this material. In this study, the effect of aging time on fracture toughness was investigated to evaluate the measurement of material degradation. The elastic-plastic fracture toughness behaviour of AISI 316 steel pipe aged at $550^{\circ}C$for 1h-10000h (the aged material) was characterized using the single specimen J-R curve technique and eletric potential drop method at normal loading rate(load-line displacement speed of 0.2mm/min) in room temperature and air environment. The fracture toughness data from above experiments is compared with the $J_{in}$ obtained from predicted values of crack initiation point using potential drop method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.8
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• pp.758-769
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• 1991

We have investigaed the radio data system which is used for the VHF/FM streo broadcasting system. The RDS system has the I6 important service features which is given by the digital multiplexed modulation method above the FM stereo baseband spectrum. The related cicuit system and general-purpose micro-controller have been applicated for the demodulation and processing of transmitted digital information at the rate of 1187.5bps, and we have developed the receiver system which performs the primary 5 features. The develpoed system has the complete compatibility with the conventional FM-car stereo receiver, we have analyzed the received RDS signal via the hardware implementation.

• Journal of Internet Computing and Services
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• v.7 no.3
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• pp.31-39
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• 2006

Ubiquitous and pervasive environment presents opportunities for a rich set of location aware applications such as car navigation and intelligent robots, interactive virtual games, logistics service, asset tracking etc. Typical indoor location systems require better accuracy than what current outdoor location systems provide, Outdoor location technologies such as GPS have poor indoor performance because of the harsh nature of indoor environments, In this paper we present a novel reducing interference location system that is particularly well suited to support context aware computing. The system, called EEM (Enhance Envelop Method) alms to combine the advantages of real time tracking systems that implement distributed environment with the suitability of infrastructure sensor network.

• The Journal of the Korea Contents Association
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• v.8 no.6
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• pp.66-73
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• 2008

The concept of u-Vehicle is a technological model that people try to build the ubiquitous world in the car which moves, by using the RFID technology as well as the telematics service based on the location. RFID is weak on the point of information security because RFID has possibility for being abused such as chasing, counterfeiting, and invading personal privacy. RFID's tags use a weak cryptographic algorithm. This paper presents the vulnerabilities of information security under u-Vehicle environments. To solve that, we propose a mechanism enhancing RFID tag's security but with low cost by reducing the number of mutual authentication stages and using the hash function.

• Journal of Digital Convergence
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• v.12 no.6
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• pp.259-264
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• 2014

Digital convergence means a service or new product which appeared through fusion of unit technologies in information and communication regions. In 2011, The Government introduced "IT Convergence Technology Prediction Survey 2025". Smart mobility is a main factor in smart city which is main example of convergence. A intelligent transport system(ITS) is a key factor of smart mobility. The conventional transport systems include road, car, signal systems. But the ITS is a transport system containing additional technologies such as electronics, control, communication to increase traffic safety and effectiveness of traffic facilities. In this paper, we described intelligent transport system related with our life.

• Korean Journal of Occupational Health Nursing
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• v.9 no.1
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• pp.56-61
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• 2000

This study was done in an attempt to reveal those factors interfering with the observation study. Three trained research assistants collected data by observing the two occupational health nurses working in the small scale enterprises on the 3rd and 10th of February, 1999. The first observation was performed on the 3rd of February without observation guidance. Guidance was given during the second observation on the 10th of February. These data were compared between reporters in nursing services of 'Workplace visiting', 'Health counselling' and 'Blood pressure checking' according to nursing time and frequency. These areas were chosen because these activities were regarded as clearly identifiable by observers in contrast to the other performances. The data showed inconsistency between reporters. However, they were reduced when reporters observed nurses with guidance, although there were still minor differences between data in time and frequency. Discussions were carried out to find possible reasons for these differences. The causes were mainly attributed to the difficulty in workplace conditions to observe, the work specificity of nurses visiting each workplace and the delicate situation between nurses and observers when reporters were travelling in the nurse's car. Therefore, the results suggest that the observation method applied to the nursing service research at small-scale enterprises should be more concerned about the selection of appropriate workplace and operational definition of nursing activity in order to more precisely measure nurses' attitudes.

• Human Ecology Research
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• v.54 no.2
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• pp.131-139
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• 2016

This study analyzes the welfare services and spatial composition of social welfare centers that represent complex welfare facilities in order to provide basic information for the spatial planning of social welfare centers. We examined 15 social welfare centers built in the 2000s. A literature review and case study were used as research methodology. The findings are as follow. First, services provided at the surveyed facilities overlapped for seniors and the handicapped. Most social welfare centers provided welfare services for seniors, young children, and teenagers. Second, the proportion of common area, program rooms was high for spatial composition. Third, front access by car was most common (used at nine centers) for the design of the access area and used by. Fourth, shared entry and exit was most common (used at 10 centers) for the design of the entrance. Fifth, regarding space combining style, a mixed style was most frequently used (observed at seven centers) where different private areas for different service users were partly mixed on certain floors. Sixth, a corridor type was most common (used at seven centers) for the design of a corridor space where visitors could walk along the corridor to access individual rooms. Based on the findings, we propose spatial composition of social welfare centers to promote mingling and exchanges among users of different generations.

• 연구논문집
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• s.27
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• pp.57-73
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• 1997

The bogie between the track and the railway vehicle body, is one of the most important component in railroad vehicle. Its effects on the safety of both passengers and vehicle itself, and on the overall performance of the vehicle such as riding quality, noise and vibration are critical. The bogie is mainly consisted of the bogie frame, suspensions, wheels and axles, braking system, and transmission system. The complex shapes of the bogie frame and the complicate loading condition (both static and dynamic) induced in real operation make it difficult to design the bogie frame fulfilling all the requirements. The complicated loads applied to the bogie frame are i) static load due to the weight of the vehicle and passengers, ii) quasi-static load due to the rolling in curves iii) dynamic load due to the relative motion between the track, bogie, and vehicle body. In designing the real bogie frame, fatigue analysis based on the above complicated loading conditions is a must. In this study, stress analysis of the bogie frame has been performed for the various loading conditions according to the UIC Code 6 15-4. Magnitudes of the stress amplitude and mean stress were estimated based on the stress analysis results to simulate the operating loads encountered in service. Fatigue strength of the bogie frame was evaluated by using the constant life diagram of the material. 3-D surface modelling, finite element meshing, and finite element analysis were performed by Pro-Engineer, MSC/PATRAN, and MSC/NASTRAN, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1146-1152
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• 2003

Satellite television receiving antenna is required for watching TV on the vehicles, ship and car. Recently TV is not only facility as getting information but one of utility in our life. In Korea, already on the service multi-channel satellite TV using excellent visibility and sound, and there are many users using now by fixing antenna. On this thesis, developed ship's satellite TV receiving antenna, the azimuth controlling is adopted azimuth information using gyro sensor and differential of receiving signal strength algorithm, and elevation controlling used gimbals. The result of this research is successfully implemented Korean satellite tracking antenna as performance until ${\pm}$30 degree roll and pitch of ship motion.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.766-767
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• 2015

In recent days, mart or department which have large parking lots provide service for finding parked cars using NFC and GPS technology. In case using NFC, users should directly tap NFC tag, and GPS does not work inside the parking garage. In this paper, garage parking indicator system using becoan served push notification is described. By using this system, users can automatically be aware where they parked car when they enter into the huge parking lot. This system overcomes the weakness of the existing parking indicator systems, such as using NFC tag system and using GPS system.