• Journal of Trauma and Injury
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• v.30 no.2
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• pp.25-32
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• 2017

Purpose: The use of computed tomography (CT) to evaluate acute abdominal complaints has increased over the past two decades. We investigated how the clinical practice of patients with intestinal perforation has changed with the increasing use of abdominal CT in the emergency department (ED). Methods: We compared ED arrival to CT time, ED arrival to surgical consultation time, and ED arrival to operation time according to the method of diagnosis from 2003-2004 and 2013-2014. Results: In patients with gastrointestinal perforation, time from ED arrival to CT was shorter ($111.4{\pm}66.2min$ vs. $199.0{\pm}97.5min$, p=0.001) but time to surgical consultation was longer ($135.1{\pm}78.8$ vs. $77.9{\pm}123.7$, p=0.006) in 2013-2014 than in 2003-2004. There was no statistically significant difference in time to operation for perforation confirmed either by plain film or CT between the two time periods. There was no statistically significant difference in length of hospital or ICU stay or mortality between the two groups. Conclusion: With the increasing use of abdominal CT in ED, ED arrival to CT time has decreased and ED arrival to surgical consultation time has increased in gastrointestinal perforation. These changes of clinical performance do not delay ED arrival to operation time or adversely influence patient outcome.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.2
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• pp.597-604
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• 2014

In this study, we investigate to show the limitations of current bus arrival time estimation model based on each bus route, and to propose a bus arrival time estimation model based on a bus stop to overcome these limitations. Using the characteristic of bus arrival time calculated on travel time between two bus stops, we develop a model to estimate bus arrival times with the data of all buses traveling the same section regardless of bus route numbers. In the proposed model, an estimated arrival time is calculated by weighted moving average method, and verification between observed value and estimated time is performed on the basis of RMSE. Error was reduced by up to 20% compared to the existing models and the data update period was reduced by more than half that is related to the accuracy of bus arrival time information. We expect to solve the following problems with the suggested method: sudden increase or decrease in arrival time of the bus, the difference of the expected arrival times at the same stop between two or more buses having different route numbers, and impossibility of offering information of a bus if the bus is not operated with the designated schedule.

• Journal of the Korean Statistical Society
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• v.35 no.3
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• pp.281-303
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• 2006

In an earlier work, we investigated the problem of using linear programming to bound performance measures in a discrete time Jackson network. There it was assumed that the system evolution is controlled by the early arrival scheme. This assumption implies that the system can't be modelled by a Markov chain. This problem was resolved and performance bounds were calculated. In the present work, we use a modification of the early arrival scheme (without corrupting it) in order to make the system evolves as a Markov chain. This modification enables us to obtain explicit expressions for certain moments that could not be calculated explicitly in the pure early arrival scheme setting. Moreover, this feature implies a reduction in the linear program size as well as the computation time. In addition, we obtained tighter bounds than those appeared before due to the new setting.

• Journal of Korea Society of Digital Industry and Information Management
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• v.9 no.4
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• pp.127-134
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• 2013

While there are many services that can check current traffic condition and application program such as bus arrival alarm are developed, since it only provide simple alarm and check level of information, it is still insufficient in many senses. Therefore, the program that try to develop in this study is the system that predict arrival time to destination and inform the bus passengers by applying real time traffic information. The system developed related to this study is still very inadequate. In the system developed in this thesis, when the user input the current bus number and destination using smart-phone, relevant server acquire the bus route information from bus information DB, and analyze real time traffic information based on the information from traffic information DB, and inform customer of expected arrival time to destination. In this thesis, traffic congestion can be eased off and regular operation of public transportation can be improved with reliable destination arrival alarm. Also, it is considered that pattern of bus users can be analyzed by using these information, and analyzing average transport speed and time of public transportation, travel time depending on various situation can give a boost to study related to transportation information and its development.

• The KIPS Transactions:PartA
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• v.10A no.4
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• pp.381-388
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• 2003

Location tracking is used to keep track of the location information of a mobile terminal in an idle state for a cail setup between mobile terminals. In this paper, we introduce a location update algorithm based on the call arrival history, which is appropriate for a variable call arrival rate over time. The location tracking strategy which uses the proposed algorithm can find changes in the call arrival rate by maintaining a call arrival history of a mobile terminal, from which a mobile terminal can calculate an appropriate timeout interval for a variable call arrival rate. We show that the proposed scheme is appropriate for a variable call arrival rate by presenting a simple analytical model and analytical results to investigate its performance for both a fixed and a variable call arrival rate.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.6
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• pp.101-111
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• 2017

This study propose a method to predict the bus arrival time by considering the signal delay time which is an element which can not be considered in the current bus arrival prediction information generation algorithm. In order to consider the signal delay time, travel time is divided into three components: service time, cruising travel time, and signal delay time. Signal delay time was estimated using intersection arrival time and TOD. The results show that most of the errors that occurred in predicting the arrival time are within about 30 seconds. Some of the estimates have large errors due to the nature of this methodology that uses the estimated value of the intersection arrival time rather than the observation value. It is also difficult to predict the arrival time of the express buses using this method. Future studies such as improving this through real-time location information will greatly improve the accuracy of the methodology.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.10
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• pp.1-8
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• 2000

In this paper, positioning schemes based on AOA(Angle of Arrival), TOA(Time of Arrival), and TDOA(Time Difference of Arrival) measurements are reviewed and analyzed. In the case of using those schemes in microcell structure with severe multipath fading and shadowing conditions, the rapid and unpredictable variation of signal level makes it difficult to estimate the position and velocity of mobiles. Therefore, we propose a novel mobile tracking method based on the multicriteria decision making, in which uncertain parameters such as RSS(Received Signal Strength), the distance between mobile and base station, the moving direction, and the previous location are participated in the decision process using aggregation function in fuzzy set theory. Through a simulation, we analysis the impaction of the frequent change of direction and speed of mobiles.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.5
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• pp.1075-1078
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• 2002

Objective: The management for the stroke should ,given as soon as possible to be effect. But Patients with stroke symptoms commonly delay many hours before seeking medical attention. We evaluated the factors which are related to the time of hospital arrival after acute stroke. Method: Data were obtained from 317 patients admitted to our hospital within 72 hours of stroke onset. We assessed demographic variables, stoke subtype. referral routes. history of previous stroke, level of consciousness, distance from the place where stroke occurred to hospital, and the time interval between onset of stroke and arrival at the hospital. Results: Mean patient age was 65.99±9.57 years. The mean time interval between onset of stroke and hospital arrival was 17.26±18.69 hours and 128 (40.38%) patients arrived within 6 hours. The patients whoes stoke subtype was infarction, who arrived our hospital by way of other hospital, who had no suffered from previous stroke and who showed no impairement of consciousness was arrived at the hospital late(p<0.05). Conclusion: The majority of patients arrive at the hospital after prolonged delays for multiple reasons, and patients with milder symptoms, for whom treatment might be more effective, were less likely to arrive in time for therapy. Our study suggest that effective education about stroke to the patients and public would be highly necessary.

• Journal of Nutrition and Health
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• v.31 no.8
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• pp.1347-1354
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• 1998

The purposes of this study were to : (a) anlayze wating time, service rate, arrival rate, and coustomer expectations/satisfaction in cafeteria business foodservices and (b) identify the differences in those factors between foodservices by menu managmenet systems. The samples were two business foodservices operated by contract management in Seoul. The queue, laptime , service rate, and arrival rate were measured at each foodservice by stopwatch observation. The menu type, delivery system, number of meals served , servide time, and turnover rate of each foodservic was investigated. Questionnaires were developed to survey customer expectations and satisfaction. Satistical data analysis was completed using the SAS package programs for descriptive analysis and t-test. The mean waiting time of island type dafeteria system with separte set -menu was shorter than that of the other. In both foodservices, arrival rates were not significantly different from one another , but sevice rates were significnatly high in dafeteria menu systems. The peak time of the queue was found out at combination set menu line. The separate set menu line had a higher servide rate than the combination set menu line. The mean waiting time of the island type cafeteria line was shorter than that of the straifth type . At the straight type dafeterial line, both arrival rate and service rate were higher than those of island-type. The results of this study suggested that a separate set-menu would be more desirable than a combination set-menu in case of providing set menu with cafeteria menu.

• Journal of Korean Institute of Industrial Engineers
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• v.38 no.1
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• pp.31-40
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• 2012

Distributed arrival time control (DATC) is a distributed feedback control algorithm for real-time scheduling problems in dynamic operational environment. Even though DATC has provided excellent performance for dynamic scheduling problems, it can be improved by considering the following considerations. First, the original DATC heavily depends on the quality of initial solution. In this paper, well-known dispatching rules are incorporated DATC algorithm to enhance its performance. Second, DATC improves its solution with adjusting virtual arrival times of jobs to be scheduled in proportion to the gap between completion time and due date iteratively. Since this approach assigns the same weight to all gaps generated with iterations, it fails to utilize significantly more the latest information (gap) than the previous ones. To overcome this issue we consider exponential smoothing which enable to assign different weight to different gaps. Using these two consideration This paper proposes A-DATC (Advanced-DATC). We demonstrate the effectiveness of the proposed scheduling algorithm through computational results.