• Journal of KIISE:Information Networking
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• v.28 no.3
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• pp.347-354
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• 2001

This paper proposes and analyzes an error control scheme which tries to recover the transmission error within the deadline of a message on FDDI networks. The error control procedure does not interfere other normal message transmissions by delivering retransmission request via asynchronous traffic as well as by delivering retarnsmitted message via overallocated bandwidth which is inevitably produced by the bandwidth allocation scheme for hard real-time guarantee. The receiver counts the number of tokens which it meets, determines the completion of message transmission, and finally sends error report. The analysis results along with simulation performed via SMPL show that the proposed scheme is able to enhance the deadline meet ratio of messages by overcoming the network errors. Using the proposed error control scheme, the hard real-time network can be built at cost lower than, but performacne comparable to the dual link network.

• Journal of Korean Society of Transportation
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• v.22 no.4 s.75
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• pp.57-68
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• 2004

It is very important to construct advanced recall systems in aspects of developing auto industry through strengthening international competitive power, as well as protecting the lives from traffic crashes by vehicle defects. Under the self-certification system, there may be high probability to be defected vehicles because vehicles are sold without testing and approval of governmental sides, even though the system was introduced to give an autonomy to manufactures. Accordingly, it is not optional, but essential concerns to build advanced recall system. As a result of analysis, manufacturers and consumers ask for improvements of domestic recall systems. In this study, policy guidelines were provided on the basis of analyses on several regulations and questionnaires of consumers and manufacturers. The policy guidelines are clearness of recall subjects, prompt collection of vehicle defect information, objective determination of vehicle defects, continuous monitoring of vehicle recalls, etc.

• Journal of Korean Society of Transportation
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• v.32 no.2
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• pp.170-178
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• 2014

Until now, several research on the relationship of traffic crash occurrences and geometric had been conducted and revealed that projects of road alignment, geometric improvement and hazardous segment selection reduced the number of accidents and accident severities. However, such variables did not consider the non-homogeneous characteristics of roadway segments due to the difficulty of data collection, which results in under-estimation of the standard error affecting the overall modeling goodness-of-fit. This study highlights the importance of non-homogeneity by looking at the effect of the non-homogeneous geometric variables through the modeling process. The model delivers meaningful results when using some geometric variables without relevant geometrics' variables.

• Health Policy and Management
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• v.30 no.3
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• pp.335-344
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• 2020

Background: The purpose of this study was to identify factors inhibiting access of people with disability to health check-ups as well as identify pertinent solutions for improvement. Methods: Twenty-three people with disability older than the age of 19 who took respective health check-ups within the last 3 years were selected as participants. For the data collection, the 1:1 intensive interview was used. The data were analyzed by the grounded theory by Corbin and Strauss. Results: The results comprised nine categories, 23 subcategories, and 179 concepts. The central phenomenon was 'failure to obtain check-ups.' Causal conditions were observed as a 'lack of communication method,' 'physical difficulties,' and 'staff unfamiliar with people with disability,' Interventional conditions comprised 'physical accessibility,' 'staffs' competency,' and 'assistant manpower.' The active strategy was included 'to investigate the professional medical institution,' 'to find the medical institution of convenient traffic accessibility,' 'to overcome communication difficulties through equipment,' and 'to overcome linguistic barriers through sufficient communication.' Whereas, 'utilization of ancillary equipment,' 'the education of staffs on people with disability,' 'universal design manual,' and 'customized check-ups' were included in the passive strategy. Such processes arose in the contextual conditions of 'lack of expectations for daily lives' and 'lack of government support.' As a consequence, the subjects participated experienced the 'disadvantages,' 'discrimination,' and 'reduced reliability of the health check-ups.' Conclusion: The subjects who participated in this study emphasized 'staffs familiar with people with disability' and 'systems customized for people with disability' are mandatory to secure complete health check-ups for people with disability.

• Journal of Advanced Navigation Technology
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• v.4 no.2
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• pp.171-181
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• 2000

In this paper, we propose an AVLS(Automatic Vehicle Location System) using the DSRC(Dedicated Short Range Communication) which adopts a radio communication tool between RSE(Road-Side Equipment) and OBE(On-Board Equipment) on a vehicle and uses the ISM bandwidth of 5.8GHz radio frequency. Typical AVLS uses the sensors for detecting the vehicle, but the DSRC system is developed for supporting various services such as the position of vehicle, clearance, vehicle to vehicle communication, collection and distributions of traffic and road information. Also, for fast processing, we design three-layer configuration of physical(L1), data link(L2), and application layer(L7), which simplifies the seven-layer configuration. We suggest the proposed system as a new technology for replacement of typical wireless communication system and sensors for AVLS.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.5
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• pp.937-945
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• 2016

Recently, Rural tourism in China is developing rapidly, however, the rural tourism remains unsatisfactory due to ignoring the landscape aspect which is considered as an integral part for rural tourism. Therefore, we aim to investigate the effect of the landscape elements on vitalization of rural tourism by evaluation of the landscape elements. To this end, we made a questionnaire survery concerning importance and satisfaction of landscape elements through factor analysis, and clamp IPA analysis. As the result, 1) Regional product, safety facilities and public parking lots are the primary considerations as primary factor. 2)Traffic facilities and accommodation should reflect regional characteristics; Garbage collection facility, food and beverage facilities, network and electricity facility should be rectified and maintained; Regaining the original nature characteristics of river and lake, Securing the integrity of the visual appreciation by shelter landscape for Sewage Purification. Our study results may provide a basic reference for the development and management of rural tourism attractions in China.

• Journal of Korea Port Economic Association
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• v.29 no.2
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• pp.211-238
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• 2013

The Port Logistics Information System (Port-MIS) is the system that processes all of port management such as entry and departure of ships, using facilities within ports, port traffic control, cargo entering and carrying and tax collection in 31 trade ports over the whole country. Lately, The Port Logistics Information System (Port-MIS) has been reformed as a WEB-based system and established basis to provide real time information support structure, diversification of civil complaint system, and optimized civil complaint service by using wire and wireless internet. The typical study on the Port Logistics Information System was C/S program and EDI-centered. But it has significance to study on service quality measurement of WEB Port-MIS that has been served as a new web-based platform since April 2010, for there was no such a study until now.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.3
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• pp.1510-1532
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• 2017

In smart grid, privacy implications to individuals and their families are an important issue because of the fine-grained usage data collection. Wireless communications are utilized by many utility companies to obtain information. Network coding is exploited in smart grids, to enhance network performance in terms of throughput, delay, robustness, and energy consumption. However, random linear network coding introduces a new challenge for privacy preserving due to the encoding of data and updating of coefficients in forwarder nodes. We propose a distributed privacy preserving scheme for random linear network coding in smart grid that considers the converged flows character of the smart grid and exploits a homomorphic encryption function to decrease the complexities in the forwarder node. It offers a data confidentiality privacy preserving feature, which can efficiently thwart traffic analysis. The data of the packet is encrypted and the tag of the packet is encrypted by a homomorphic encryption function. The forwarder node random linearly codes the encrypted data and directly processes the cryptotext tags based on the homomorphism feature. Extensive security analysis and performance evaluations demonstrate the validity and efficiency of the proposed scheme.

• Korean Journal of Health Education and Promotion
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• v.22 no.4
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• pp.41-56
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• 2005

Objectives: More than 80% of unintentional injury was related to risk-taking behaviors involved in child accidents. Therefore, diverse care and concerns on safety should be provided from teachers as well as parents to build child safety behaviors. The purpose of this study was to identify the effects of safety concerns from students, teachers, and parents on elementary students' safety behaviors in Korea. Methods: The 5th and 6th grade students participated in this study in 14 elementary schools in Korea and the total number of students was 1,033. The study schools were selected by the stratified cluster sampling method throughout 7 metropolitan areas in Korea. Data were collected by the self-administered survey and the questionnaires were delivered to the vice-principals of the designated schools by ground postal service and the vice-principals conducted survey data collection. The questions on students' safety concerns, teachers' safety concerns, parents' safety concerns, safety practices, safety education, and demographics were included in the survey. All survey responses were encoded into SPSS program and t-test, ANOVA, and multiple regression analysis were utilized. Results: The students taking accidents one time more per year were more than 60% and the two thirds of them recognized that their accidents were due to their risk behaviors. Parents' education on safety practices was more frequent than teachers' education; furthermore, teachers' concerns on safety behaviors were poorer than students' or parents' concerns. In terms of safety behaviors, the scores of fire and home-related safety behavior were high but the scores of traffic and bicycle, in particular, helmet wearing practice were low. Three concerns from students, parents, and teachers all were significantly related to children's safety behaviors. Conclusions: In conclusion, safety concerns from the close networks are the important indicator of child safety behaviors and, the safety training programs, therefore, for parents and teachers as well as for students need to be developed for improving children's safe behaviors.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.6B
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• pp.527-533
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• 2006

In this paper, we analyze the performance of MAC (Media Access Control) layer in DSRC (Dedicated Short Range Communication). It will be widely applied for ITS (Intelligent Transportation System) services; for example ETC (Electric Toll Control), BIS (Bus Information System) etc., needed to small packet size. But If ITS service is evolving to advance ITS, ADIS (Advanced Driver Information Systems) and AVHS (Advanced Vehicle Highway System) etc, be needed larger packet size. In the future, it may offer more various services such as traffic information, collection, and multimedia information. There are two kind of physical media, IR(Infrared) and RF(Radio frequency). And each system has their own protocol that is adaptive in special characteristics of physical medium for using efficiently limited radio resources. In this paper, we analyze the special characteristics of each system. And we study practical use of some related services expected to be used in the near future, by analyzing the transmission efficiency in each DSRC system.