• Journal of Korean Society of Transportation
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• v.35 no.1
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• pp.63-78
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• 2017

The purpose of this study is to determine the optimal aggregation interval to increase the reliability when estimating representative value of individual vehicle travel time collected by DSRC equipment in interrupted traffic flow section in National Highway. For this, we use the bimodal asymmetric distribution data, which is the distribution of the most representative individual vehicle travel time collected in the interrupted traffic flow section, and estimate the MSE(Mean Square Error) according to the variation of the aggregation interval of individual vehicle travel time, and determine the optimal aggregation interval. The estimation equation for the MSE estimation utilizes the maximum estimation error equation of t-distribution that can be used in asymmetric distribution. For the analysis of optimal aggregation interval size, the aggregation interval size of individual vehicle travel time was only 3 minutes or more apart from the aggregation interval size of 1-2 minutes in which the collection of data was normally lost due to the signal stop in the interrupted traffic flow section. The aggregation interval that causes the missing part in the data collection causes another error in the missing data correction process and is excluded. As a result, the optimal aggregation interval for the minimum MSE was 3~5 minutes. Considering both the efficiency of the system operation and the improvement of the reliability of calculation of the travel time, it is effective to operate the basic aggregation interval as 5 minutes as usual and to reduce the aggregation interval to 3 minutes in case of congestion.

• Journal of Advanced Navigation Technology
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• v.10 no.4
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• pp.291-298
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• 2006

A new intelligent paging algorithm is proposed in this paper to maximize the paging capacity in wireless link of mobile communication systems. Intelligent paging algorithms have been studied to utilize limited wireless resource efficiently, in which a location area is divided to several paging areas which are searched sequentially. Previous intelligent paging methods mainly use location probability distribution of the paging target terminal to determine paging areas. However, these methods make the paging traffic of each cell non-uniformly distributed. Therefore, in relatively low paging load conditions, there exist cells congested with paging traffic in which paging traffic queues are overflowed and paging messages are lost. The proposed method determines paging areas to make the paging traffic distributed uniformly among cells by considering current paging traffic distribution in each cell. Performance evaluation shows that the proposed method outperforms the previous paging schemes much with respect to paging processing capacity.

• Journal of Physiology & Pathology in Korean Medicine
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• v.33 no.3
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• pp.181-190
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• 2019

In South Korea, traffic accident patients can be treated under automobile insurance coverage. This study investigated the status of Korean medicine (KM) Automobile insurance system and usage status of main pharmacopuncture in KM clinic which reported that the largest number of automobile insurance fee claims among medical institutions. We surveyed 258 traffic accident patients who were treated at Namsangcheon KM clinic from 2014 to 2018 according to medical chart. The majority of the patients were male and thirties. In traffic accident situation, the highest distribution was car to car crash with 85.66% and 66.67% of the patients visited in the most acute phase. The most frequent treatment period was within 4 weeks and the number of treatments was 10 or less with 72.87%. In total results of treatment, the distribution was exellent with 10.08%, good with 46.90%, fair with 27.13% and poor with 15.89%, and the effective rate was 84.11%. The most frequent treatment period was within 4 weeks with 64.73% and the number of treatments was 10 or less with 72.87%. Of the 242 patients who received pharmacopunture, 91.5% were treated with HO, which was named after Honghwaja and TA, which was named after traffic accidents, and there were significant differences in the number of treatments and symptom improvement between the two groups. In this study, we confirmed the status of automobile insurance treatment and usage of main pharmacopuncture of single KM clinic with symptom improvement. This study can be regarded as one of the basis of KM treatment for the rapidly growing automobile insurance market.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1D
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• pp.11-16
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• 2009

The estimation of total travel time on highway link for a day or year is the most important process for the feasibility analysis of highway or railway. Most of current guidelines for feasibility studies have been based on the time-traffic volume relationship from the BPR, and the traffic volumes have been determined by the application of the design hour factor to the annual average daily traffic volume. Both of the BPR function and the application of the design hour volume may result in the over-estimation of travel time due to the fact that the traffic volume on the large portion of highway links in Korea are close to the capacities. This study proposed a new way which is based on the distribution of hourly volumes for a year. It could be closer to the real situation, and provide more reasonable estimation. This methodology was validated for the national highways, but may be applicable for any type of highway with the AADT.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1492-1501
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• 2015

This paper analyzes the effect of voltage sag on distribution systems due to the connection of Electric Vehicles (EVs). In order to study the impact of the voltage sag on the power system, two scenarios have been selected in this paper. The distribution system and EVs are modeled using the Electro Magnetic Transients Program (EMTP). The numbers of EVs are predicted based on the number of vehicles in distribution system of Seoul. In addition, the number of EVs is set up using real-time traffic in Seoul to simulate Scenario I and II. The simulation results show that voltage sag can occur if the distribution system has more than 30% of the total number of vehicles.

• The Korean Journal of Emergency Medical Services
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• v.1 no.1
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• pp.11-19
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• 1997

We have reviewed 2.876 patients who visited the emergency room from May, 1996 to september, 1996 in order to look for a more appropriate management of the emergency medical system. The result were summarized as followings; 1. Considering sexual distribution, male patients were 59.6% more than female patients 40.4% and according to age categories, first decade of life was most frequent. 2. Distribution according to ca use is most common for the disease 79.8%, and next injury and traffic accident is 11.6%, 6.8%, respectively. 3. According to the department distribution, pediatrics accounted for 37.4%, internal medicine 21.1%, and emergency medicine 10.0%, and these three departments was 66.3% of total number of patients. 4. 67.0% of patients visited emergency room were discharged. Arrived time in emergency room, patients of 41.9% was visited from 17 to 1 hours. 5. Among 196 patients of traffic accident, 160 were male(81.5%) and 36 were female (18.5%). Distribution of the age is most common in 3rd and 4th decade for 63.2%, and region of injury were face 33.3%, head 22.2%, and chest 22.2% and follow-up measures after visiting emergency room is most common transfer hospital 40.8%.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1816-1824
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• 2011

Recently, with traffic SOC investment policy changing from road-centered to railway-centered according to environment-friendly and sustainable development, issues regarding overlapping and overinvestment of traffic facility have been raised. Regarding investment of various traffic facilities of which departure and destination are similar to each other, academia, civic organizations, government, etc. are recognizing problems including overlapping investment of budget, environmental destruction, etc., but not suggesting definite solutions. Objective transportation network analysis is required because various positive effects including solutions of delay/congestion may occur due to provision of alternative way and distribution of the amount of traffic when accidents occur, as well as negative effects suggested by some of civic organizations in various transportation facility investment of similar departure and destination. Hereupon, this study tries to suggest a tool that can objectively evaluate interrelations of transportation network by applying multi-criteria analysis including economic feasibility regarding analysis of interconnections between and within means of transportation.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.3 no.2
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• pp.69-80
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• 1999

Recently in telecommunication, BISDN ( Broadband Integrated Service Digital Network ) has received considerable attention for its capability of providing a common interface for future communication needs including voice, data and video. Since all information in BISDN are statistically multiplexed and are transported in high speed by means of discrete units of 53-octet ATM ( asynchronous Transfer Mode ) cells, appropriate traffic control needs. For traffic shaping of voice, the output cell discarding scheme has been proposed. We analyze the scheme with a MMPP/$D_1$, $D_2$/1/B queueing system to obtain performance measures such as loss probability and waiting time distribution.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.6
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• pp.1148-1159
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• 1997

In the broadband integrated service digital networks (B-ISDN), ATM switches hould be abld to accommodate diverse types of applications ith different traffic characteristics and quality ddo services (QOS). Thus, in order to increase the utilization of switches and satisfy the QOS's of each traffic type, some types of priority control schemes are needed in ATM switches. In this paper, a nonblocking input and output queueing ATm switch with capacity C is considered in which two classes of traffics with different loss probability constraints are admitted. 'Partial push-out' algorithm is suggested as a loss priority control schemes, and the performance of this algorithm is analyzed when this is adopted in input buffers of the switch. The quque length distribution of input buffers and loss probabilities of each traffic are obtained using a matrix-geometric solution method. Numerical analysis and simulation indicate that the utilization of the switch with partial push-out algorithm satisfying the QOS's of each traffic is much higher than that of the switch without control. Also, the required buffer size is reduced while satisfying the same QOS's.

• Journal of Electrical Engineering and information Science
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• v.3 no.1
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• pp.73-79
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• 1998

In this paper, a new traffic sign detection algorithm.. and a symbol recognition algorithm are proposed. For traffic sign detection, a dominant color transform is introduced, which serves as a tool of highlighting a dominant primary color, while discarding the other two primary colors. For symbol recognition, the curvilinear shape distribution on a circle centered on the centroid of symbol, called a circular pattern vector, is used as a spatial feature of symbol. The circular pattern vector is invariant to scaling, translation, and rotation. As simulation results, the effectiveness of traffic sign detection and recognition algorithms are confirmed, and it is shown that group of circular patter vectors based on concentric circles is more effective than circular pattern vector of a single circle for a given equivalent number of elements of vectors.