• Journal of Korean Society of Transportation
• /
• v.24 no.3 s.89
• /
• pp.103-112
• /
• 2006

For recent innovation of If technology and the beginning of Digital Multimedia Broadcasting (DMB) service, it has been dramatically increased to setup TV system in a car for watching TV and receiving traffic Information. Watching TV while driving would distract a driver s cognitive and visual attention as eating food, operating the radio, using a cell phone. However, there is paucity of empirical researches and it is uncertain how watching TV in driving impacts on the driver's cognition in the concrete. Therefore, we surveyed domestic drivers on the attitude watching TV while driving as well as conducted experiments through a driving simulator. Especially, we recruited two groups of participants to explore the effects of watching TV on driving behavior. The result proved that the participants who watched TV while their driving had relatively narrower the attention span than the Participants who did not watch TV. Also, those who watched TV drove with less stability and more urgent operations of the brake and accelerator than those who did not watched TV Finally, we discussed limitations and implications of the study.

• Transactions on Electrical and Electronic Materials
• /
• v.14 no.4
• /
• pp.211-215
• /
• 2013

Partial discharge diagnosis techniques using ultra high frequencies do not affect load movement, because there is no interruption of power. Consequently, these techniques are popular among the prevention diagnosis methods. For the first time, this measurement technique has been applied to the GIS, and has been tested by applying an extra high voltage switchboard. This particular technique makes it easy to measure in the live state, and is not affected by the noise generated by analyzing the causes of faults ? thereby making risk analysis possible. It is reported that the analysis data and the evaluation of the risk level are improved, especially for poor location, and that the measurement of Ultra high frequency (UHF) partial discharge of the real live wire in industrial switchgear is spectacular. Partial discharge diagnosis techniques by using the Ultra High Frequency sensor have been recently highlighted, and it is verified by applying them to the GIS. This has become one of the new and various power equipment techniques. Diagnosis using a UHF sensor is easy to measure, and waveform analysis is already standardized, due to numerous past case experiments. This technique is currently active in research and development, and commercialization is becoming a reality. Another aspect of this technique is that it can determine the occurrences and types of partial discharge, by the application diagnosis for live wire of ultra high voltage switchgear. Measured data by using the UHF partial discharge techniques for ultra high voltage switchgear was obtained from 200 places in Gumi, Yeosu, Taiwan and China's semiconductor plants, and also the partial discharge signals at 15 other places were found. It was confirmed that the partial discharge signal was destroyed by improving the work of junction bolt tightening check, and the cable head reinforcement insulation at 8 places with a possibility for preventing the interruption of service. Also, it was confirmed that the UHF partial discharge measurement techniques are also a prevention diagnosis method in actual industrial sites. The measured field data and the usage of the research for risk assessment techniques of the live wire status of power equipment make a valuable database for future improvements.

• Quality Improvement in Health Care
• /
• v.2 no.2
• /
• pp.20-30
• /
• 1996

Background : Theoretically as the waiting-time of patient is estimated in queueing, many men and much money are needed. But being the estimation of patient s waiting-time very important in hospital service, so the continuous monitoring of waiting-time is inevitable. To verify that the estimation of waiting-time using parking time is economical, effective and continuous monitoring method and to develop utilizing the method, this study was done. Method : In parking confirmation office, the personnel of parking office wrote parking confirm time, chart number and whether medical examination and treatment finish or not in parking ticket. The next day the parking tickets were gathered and the above data were input. The input parking data were connected with the hospital outpatient file indexing chart number. Then the patient' s data for department, new patient or not, reservation or not, receipt time and payment time were retrieved. The group for finishing medical treatment were compared with that for not finishing in average time lag between confirmation and out-time for hospital. And In-time for hospital, receipt time, payment and out-time for hospital were also analyzed. Result : Confirming parking ticket, the group for finished medical treatment left hospital after 7 minutes. This result showed that the patient for finished medical treatment left hospital immediately. So parking time was reasonable to estimation of hospital-time was concluded. The time for medical treatment, diagnosis and test was constant for all patients and short for waiting time, Then I concluded that the parking time was reasonable for estimation patient's waiting time. Overall patient's waiting time was 113 minutes and new patient's time was 149 minutes, old patient's times was 109 minutes. Waiting time for reservation patient was 98 minutes and for non reservation patient was 122 minutes. The time from hospital arrival to payment was 50 minutes for the group of reservation patient and 69 minutes for non-reservation group. The time from payment to hospital leaving was 51 minutes and 56 minutes for non reservation group. The short time difference between reserved group and not reserved group from payment to hospital leaving time was due to bottle neck effect. Conclusion : The estimation of patient's waiting time using parking time was reasonable because the possession of car was common and the time for medical treatment was equal and the patient after treatment left hospital immediately. Using this method, timely, fast evaluation and continuous monitoring of the intervention effect were possible.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.1
• /
• pp.75-84
• /
• 2018

Increasing the operation rate of components and stabilizing the operation through timely management of the core parts are crucial for improving the efficiency of the railroad maintenance industry. The demand for diagnosis technology to assess the condition of rolling stock components, which employs history management and automated big data analysis, has increased to satisfy both aspects of increasing reliability and reducing the maintenance cost of the core components to cope with the trend of rapid maintenance. This study developed a big data platform-based system to manage the rolling stock component condition to acquire, process, and analyze the big data generated at onboard and wayside devices of railroad cars in real time. The system can monitor the conditions of the railroad car component and system resources in real time. The study also proposed a machine learning technique that enabled the distributed and parallel processing of the acquired big data and automatic component fault diagnosis. The test, which used the virtual instance generation system of the Amazon Web Service, proved that the algorithm applying the distributed and parallel technology decreased the runtime and confirmed the fault diagnosis model utilizing the random forest machine learning for predicting the condition of the bearing and wheel parts with 83% accuracy.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.3
• /
• pp.493-500
• /
• 2017

Based on the data accumulated through EMU fault management, this paper examines the reliability of old railway car parts and proposes measurements to improve safety. Subway Line 7 of the Seoul Metropolitan Rapid Transit Corporation, auxiliary power unit (Static Inverter) of the EMU second version is a core equipment to supply power to various room-service units in cars and make an effect directly on passenger satisfaction. To analyze the pattern of failure throughout the field data over a long period of time, this analysis of statistics and reliability considers the operating environment and stress factors. This statistical analysis presents the correlation between failure and the temperature stress factors related to frequent failure occurring intensively in summer. In addition, throughout the analysis of the life of the IGBT inverter, the effect of the temperature stress factor was observed before and after the repair. As a result of an analysis of the optimal operating conditions considering two variations of EMU, such as variable load and outside temperature, a difference in the cooling capacity between the optimal operating conditions and frequent failure conditions was observed. Based on this analysis, this paper suggests a way to minimize cooling capacity difference for the optimal operational conditions.

• Journal of Convergence Society for SMB
• /
• v.2 no.1
• /
• pp.51-58
• /
• 2012

Android platform is a powerful operating system developed on Linux 2.6 Kernel, and provides many features such as comprehensive libraries, a multimedia environment, and powerful interface for phone applications. Since Android is an open operating system, which can be installed in any vendors's equipments. Current smartphones as well as netbooks, navigations, car PCs, tablet PCs, Industrial PCs are used in various fields. It is difficult a lot that to mount to other devices on the Android platform or new devices. In this Paper, The process that data that occurred from a hardware was passed to the highest application and Android platform system for managing hardware devices were analyzed. Building Android & driver compilation environment, How to support the protocol for the use of WiFi in the kernel, How to Mount a WiFi device in the kernel, Device driver registration for the Android platform, WiFi Management Service Daemon (wpa_supplicant) and IP allocation services daemon (dhcpcd) registration, How to create a socket for communication between the daemon (wpa_supplicant) and HAL have been presented. In the experiment using the proposed method, WiFi devices were mounted on the Android platform in the X-86 & ARM family. Understanding the whole process of control flow in Android hierarchy is very important to porting a new device on it. The process included in this paper can help technicians who might encounter the obstacles in their porting works.

• Journal of Korean Society of Transportation
• /
• v.24 no.7 s.93
• /
• pp.101-114
• /
• 2006

Recently due to the increase of cars and city life, the traffic congestion has worsened. It Is particularly worse in the center of the metropolis. Within the general public means, the public transport buses have the advantage of being more cheap, accessible and mobile. But as there is no separate lane for buses, the collision of cars and buses are creating damage to public service. In order to solve this situation, the bus priority signal system has been introduced to reduce the bus travel time and improve its services. The purpose of this study is to establish bus priority signal algorithm which builds bus efficiency under the real-time traffic signal control system and to analyze the effect of it. As the green time was calculated against real time (under the real-time traffic signal control system), compared to existing bus priority signal there was a reduction in cross street loss. The modified cycle was used to maintain signal progression. A case study was carried out using VISSIM simulation model. In result of this study, we found that there was a decrease in bus travel time despite some evidence of car delays and compared to existing bus priority signal the delay of dishonor could be reduced dramatically. The analysed result of person delay using MOE, is that there is evidence that when bus priority signal is in effect, the person delay is reduced.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.17 no.1
• /
• pp.55-70
• /
• 2018

Recently, as shared transportation services has expanded, integrated mobility services that link personal transportation and public transportation are paid attention. To do this, it is necessary to analyze trip mode chaining behavior. This study analyzed the characteristics of the trip mode chaining behavior using the 2010 travel diary survey in Seoul, and analyzed factors to affect mode choice of trip chaining through the multinomial logit model. The transportation means were classified into passenger cars, city buses, intercity buses, railways, taxis, and others, and 25 trip mode chaining types were identified. Among them, the trip share connected between city bus and railways was the highest. It was also found that the trip mode chaining occurred mainly at commuting and in the morning and afternoon peak. According to the model results, the mode choice of trip chaining is significantly influenced by individual attributes (sex and age), household attributes (car ownership and income), trip attributes (trip purpose, trip time and trip length), and arrival area attributes (number of subway lines and bus lines, ratio of commercial area, land use mix and central region).

• Culinary science and hospitality research
• /
• v.18 no.3
• /
• pp.1-17
• /
• 2012

This study was planned for an empirical review of foodservice operation in expressway rest areas for a menu strategy targeting staff and customers. The results were as follows. Main foodservice category included 10-30 items of Korean dishes. The needs for having branded foodservice menu in rest areas were high in fusion/fast foods, snack/ready-made and beverages. Employment of professional cooks in rest areas was low (10-30%), and the most important factor was 'taste' when cooking Korean foods. Foreigners preferred fusion/fast foods and snack/ready-made foods to Korean food, beverages and Japanese/Chinese foods, and most of the foreigners ordered food with 'no question'(55.5%) or 'some questions'(34.8%). Rest area staff prepared some photos/pictures of foods (80-100%) for menu comprehension, but the accuracy of menu transcription was very low. Customers used a rest area once or twice, stayed for 10-20 min(43.6%)/20-30 min(38.6%), visited by car(77.7%) to relax and use toilets(61.6%) on average. Favorite food and snacks were Korean(32.7%) and ready made/snacks(33.0%), and they spent 5,000-10,000 won(51.3%), 3,000-5,000 won(25.8%) on them. Customer satisfaction with rest areas was 'average' regardless of gender, age, education levels and jobs. With this analysis, we should prepare an efficient menu strategy for customer satisfaction and plans for analyzing problems along with alternatives.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.11 no.5
• /
• pp.531-538
• /
• 2016

Driving behaviors such as speeding and illegal u-turn which violate traffic rules are main causes of car accidents, and they can lead to serious accidents. Bus drivers are less aware of dangers of illegal u-turn, and infrastructures such as traffic enforcement equipment and watchmen are deficient. This research aims to develop technology for estimating driving behaviors based on map-matching in order to prevent illegal u-turns. For this research, 23,782 of u-turn permit data and 146,000 of speed limit data are collected nationwide, and an estimation algorithm is built with these data. Then, an application based on android is developed, and finally, tests are conducted to assess the accuracy in data computations and GPS data map-matching, and to extrapolate driving behavior. As a result of the tests, the accuracy results in the map-matching is 86% and the assessment of driving behavior is 83%, while the display of the data output yielded 100% accuracy. Additional research should focus on improvement in accuracy through the development of a robust monitoring system, and study of service scenarios for technology application.