• Journal of the Korean Geographical Society
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• v.43 no.3
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• pp.358-374
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• 2008

This study examines whether and how ages of child affect accessibility experiences of women and men differently. Space-time accessibility measures based on Time-geographic framework with activity-travel diary datasets in Portland Metro, US were calculated using GIS-based geocomputation, and spatial-temporal patterns of accessibility of dual-earner couples by ages of their youngest child were compared. The results are as follows. (1) Although more women than men work part-time, which would render women more spatial-temporal autonomy, accessibility levels of women are not higher than men's. It implies that there exists another constraint placed on women which largely stems from gender inequality. (2) It is distinctively women with child under age 6 of which accessibility spaces are found to be restricted doser to home compared to men. Women with no child or with child aged over 6, however, show more or less similar spatial-temporal patterns of accessibility with men's which are quite unvarying regardless of parental status and their child age. Women's accessibility experiences characterized by spatial-temporal entrapment, thus, can be seen as problems associated with gender rather than sex. (3) Intensified spatial-temporal entrapment of women with young child are associated with the significant spatial pegs shaping their accessibility spaces, which are located much closer to home compared to men's: workplaces and child's daycare centers.

• Journal of Korean Society of Transportation
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• v.30 no.1
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• pp.135-147
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• 2012

The benefit of traffic information on variable message sign can be divided into two. At the public level, the benefit of ATIS is the travel time saving, which is not only induced from ATIS, but also mixed with that of ATMS. In the economic appraisal of ITS, the benefit of ATIS has so far been regarded as the derived benefit from ATMS. At the user level, the benefit of ATIS is reduced driver uncertainty through the forward traffic status information. User can benefit from the information on VMS and therefore may have the willingness to pay for it. Recently attempt to qualify the value of information on VMS was increased, but there was a danger of distorting or over-estimates of the ATIS benefit because the related studies didn't consider the time-dependent attributes of traffic information and provided the single value. Estimates of the time-varying value should be needed for a rigorous economic appraisal of ATIS. In this study, we varied the value of information on VMS according to peak and non peak trip and verified the hypothesis that time-varying of value was statistically significant.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.1 s.4
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• pp.45-52
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• 2004

There are many cities installing ITS(Intelligent Transportation Systems) and running TMC(Trafnc Management Center) to improve mobility and safety of roadway transportation by providing roadway information to drivers. There are many devices in ITS which collect real-time traffic data. We can obtain many valuable traffic data from the devices. But it's impossible to avoid missing traffic data for many reasons such as roadway condition, adversary weather, communication shutdown and problems of the devices itself. We couldn't do any secondary process such as travel time forecasting and other transportation related research due to the missing data. If we use the traffic data to produce AADT and DHV, essential data in roadway planning and design, We might get skewed data that could make big loss. Therefore, He study have explored some imputation techniques such as heuristic methods, regression model, EM algorithm and time-series analysis for the missing traffic volume data using some evaluating indices such as MAPE, RMSE, and Inequality coefficient. We could get the best result from time-series model generating 5.0$\%$, 0.03 and 110 as MAPE, Inequality coefficient and RMSE, respectively. Other techniques produce a little different results, but the results were very encouraging.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.3
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• pp.45-51
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• 2016

Existing real-time signal control system was brought up typical problems which are supersaturated condition, point detection system and loop detection system. For that reason, the next generation signal control system of advanced form is required. Following thesis aimed at calculating queue length for the next generation signal control system to utilize basic parameter of signal control in crossing queue instead of the volume of real-time through traffic. Overflow saturated condition which was appeared as limit of existing system was focused to set-up range. Real-time location information of individual vehicle which is collected by GPS data. It converted into the coordinate to apply shock wave model with an linear equation that is extracted by regression model applied by a least square. Through the calculated queue length and link length by contrast, If queue length exceed the link, queue of downstream intersection is included as queue length that upstream queue vehicle is judeged as affecting downstream intersection. In result of operating correlation analysis among link travel time to judge confidence of extracted queue length, Both of links were shown over 0.9 values. It is appeared that both of links are highly correlated. Following research is significant using real-time data to calculate queue length and contributing to signal control system.

• Journal of Korean Society of Transportation
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• v.27 no.2
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• pp.199-206
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• 2009

In relation with economical efficiency analysis on investment evaluation of transportation system, among vehicle operating cost saving benefit that is applied to general preliminary assessment guidelines and investment evaluation guidelines, oil expense calculated data which concentrated and analyze on the relationship between oil consumption amount on running state and running speed. For uninterrupted flow which does not have stopped delay due to traffic signal, consideration for reduction benefit is possible due to the changes of running speed and travel time however, for interrupted flow which the stopping occurs due to signal control on actual signal intersection has no consideration for stopping delay time reduction and stopping rate improvement thus reflection of reality on improved effect analysis is difficult. Therefore, this research makes a framework to analyze benefits that reflects the features of signalized intersections by benefits associated with decrease of stopping delay time with existing research and developing vehicle operating cost calculation model formula. Vehicle operating cost has been redefined considering the stopping delay time by applying the oil consumption amount at idling and the economical benefit between conventional model and newly developed model when applied for the optimization of traffic signal system on the two roads in Seosan city has been analyzed comparative. While the importance of traffic system maintenance is being emphasized due to the increase of congested areas on roads, it is expected to assist in more realistic economical analysis which reflect the delay improvement through the presentation of an economic analysis model that considers the features of signalized intersections in signal optimization system improvements and effect analysis of congestion improvement projects`.

• Journal of Korean Society of Transportation
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• v.24 no.7 s.93
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• pp.65-79
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• 2006

The ATIS(Advance Traveler Information System), as one part of ITS, is a system aiming to disperse traffic volume on transportation networks by providing traffic information to transportation users on pre-trip and en-route trips. One of tools in ATIS is usage of VMS(Variable Message Signs). It provides to the drivers with direct information about state of processing direction. which is considered as the most effective method in ATIS. The purposes of providing VMS information are classified two categories. One is to provide simple information to drivers for their convenience. The other is to manage traffic demand to improve transportation network performance. However, for more effective and reliable VMS information, several strategies should be taken into account. The main VMS management strategy is "Traffic Diversion Strategy for minimum delay" when traffic congestion or incident are occurred. For effective operation. firstly. reasonable diversion traffic volume is determined by network traffic condition Secondly, it is necessary to make providing information strategy which reflects driver response behavior for controling diversion traffic volume. This paper focuses on the providing real-time route guidance information by VMS when congestion is occurred by the incidents. This sturdy estimates time-dependent system optimal diversion rate that inflects travel time and queue lengths using traffic flow simulation model on base Cellular Automata. In addition, route choice behavior models are developed using binary logit model for traffic information variable by traffic system controller. Finally, this study provides time-dependent VMS massage contents and degree of providing information in order to optimize the traffic flow.

• Journal of Korean Society of Transportation
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• v.29 no.3
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• pp.61-72
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• 2011

In the benefits of ITS, there are intangible gains from real-time traffic information as well as classical gains such as travel time saving. These intangible gains are difficult to be estimated by existing transportation investment appraisal commonly used in SOC investment. The major reason is not because of the absence of methodology but because of the absence of generalized values of particular benefits from real time traffic information. This research explores the value of real-time traffic information on VMS that is the most representative of ITS services, by using CVM with Double Bounded Dichotomous Choice Question. Willingness-To-Pay (WTP) functions of drivers are built with survival functions using various types of probability distribution functions such as Exponential, Log-logistic, and Weibull functions. The results reveal that Log-logistic distribution is the most appropriate distribution model to estimate WTP, and the estimated coefficients are stable through LR (Likelihood Ratio) test. For the further study, it is recommended to perform statistical tests of temporal and spatial transferability that is not examined in this research due to the lack of data.

• Journal of Korean Academy of Nursing
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• v.2 no.1
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• pp.87-96
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• 1971

This Study was undertaken to evaluate the present health status and fatigue of the workers in T. Industrial Company in Pusan in Jan. 1971. The results were based on a question are from 354 working girls. The results of this study are as follows: 1. The largest portion of the workers, 20.2% of the questioned employees, were observed to lie at age 20. 2. Regarding their formal education, 76.0% of them had completed middle school. while only 7. 1% had graduated from high school, . 3. 63.0% receive 7-8 hrs. of sleep a day while 18.4% receive S-6 hrs. of sleep a day. 4. 36.4% spend leisure time reading: while 15.5% spend it resting and thinking. 5. 53.8% of them live in the company′s dormitory and 31.6% live at home. 6. Time spent in travel to work: 32.8% spent 40-49 min., 23.6% spent 10-29 min. 7. The shift times were reported as: 44.1% wonting from 8 A.M. to 4 P.M. and 33.9% working from 6. A.M. to 2. P.M. which is what they are doing now. 8. Regarding symptoms of fatigue: 1) Physical symptoms were: 48.3% complained of "feeling bean in the legs, ", and 39.3% complained of "general exhaustion. " 2) Psychological symptoms were: 37.6% said that "it is boring to talk"and 26.3% said" they had a desire to be alone". 3) Nitrogenic symptoms were 49.7% complained of "asthenopia"and 37.0% complained of"vertigo and "staggering legs". 9. When asked about the most fatiguing time during work, the following information was reported: 25.2% felt the first hour in the morning was most fatiguing while 22.9% felt the sixth hour in the evening, and 22.8% eelt the fifth hour at night was. 10. 38.4% complained of sleepiness at 3 A.M. and 35.0% at 4 A.M. during night work. 11. 38.1% found Sunday the most fatiguing work day and 20.% found Monday. 12. The results of the effects of their work on certain diseases: 51.1% showed those with anemia as most effected by work. 13. In their Response to the question, "do you eat breakfast\ulcorner"57.0%, the largest portion, answered, " none at all ": 36.3%, enough. 14. Regarding the accident rate relating to the length of time employed at the company 28.5% was the highest accident rate from 5year to 6 year. As a result of this study, it could be concluded that the employer should consider the following points: 1. employ according to the worker′s vocational aptitude. 2. adjust the shifts. 3. offer rest time and off days, and establish recreational facilities. In the end we can contribute to the promotion of the workers of the workers and to the prevention of accidents due to industrial fatigue.

• International Journal of Highway Engineering
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• v.14 no.2
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• pp.93-99
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• 2012

This study analyzes traffic data which are collected by VDS(Vehicle Detection System) to research the relationship between spacing distribution and vehicles' relative speed. The collected data are relative speed between preceding and following vehicles, passing time and speed. They are also classified by lane and direction. For the result of the analysis, in the same platoon, we figure out that mean of spacing is 40m, which can be a value to determine section A to D. To compare spacing according to time interval, this study splits time intervals to peak hour and non-peak hour by peak hour traffic volume. In conclusion, vehicles in peak hour are in car following because most drive similar speed as preceding vehicle and they have relatively small spacing. On the other hand, non-peak hour's spacing between vehicles is bigger than that of peak hour. This implies driver's behaviors that the less spacing, the more aggressive and want to reduce their travel time in peak hour, whereas most drive easily in non-peak hour and recreational trip purpose because of less time pressure.

• Journal of the Society of Disaster Information
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• v.16 no.4
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• pp.650-657
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• 2020

Purpose: In this study, the effectiveness of pilot project of PLSP (Priority Lane and Signal Preference) system, which was operated in Cheongju City, was analyzed. Method: The priority signal was operated by a police officer switching to a blue signal when approaching a fire truck through CCTV, and the priority lane of emergency vehicles was displayed on the road to enable preferential traffic. VISSIM simulation analysis was performed for the 1.2km section (3.8km) of the pilot project section and vehicle data was analyzed for some of the test operation sections. Result: Simulation analysis shows that the moving speed of the emergency vehicle can be increased by 42 km/h with the introduction of PLSP, which can be increased by approximately twice the speed. Travel time was reduced by about 3 minutes, and considerable improvements of 69% compared to cities that are not operating was analyzed. The pilot operation of Cheongju City showed a time-shortening effect of about two minutes on average, with the average time reaching 4 minutes and 14 seconds in the first period and the average time reaching 5 minutes and 40 seconds in the second period. Conclusion: The system has been shown to be effective in minimizing time-to-site arrival of emergency vehicles.