• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.294-300
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• 2017

This paper proposes a method for 3-D sound source localization (SSL) using region selection and TDOA. 3-D SSL involves the estimation of an azimuth angle and an elevation angle. With the aim of reducing the computation time, we compare signal energies to select one out of three regions. In the selected region, we compute only one TDOA value for the azimuth angle estimation. Also, to estimate the vertical angle, we choose the higher energy signal from the selected region and pair it up with the elevated microphone's signal for TDOA computation and elevation angle estimation. Our experimental results show that the proposed method achieves average error values of $0.778^{\circ}$ in azimuth and $1.296^{\circ}$ in elevation, which is similar to other methods. The method uses one energy comparison and two TDOA computations therefore, the total processing time is reduced.

• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.10-18
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• 2006

We measured the changes in P-wave velocity that occur when injecting $CO_2$ in gaseous, liquid, and supercritical phases into water-saturated anisotropic sandstones. P-wave velocities were measured in two cylindrical samples of Tako Sandstone, drilled along directions normal and parallel to the bedding plane, using a piezo-electric transducer array system. The velocity changes caused by $CO_2$ injection are typically -6% on average, with maximum values about -16% for the case of supercritical $CO_2$ injection. P-wave velocity tomograms obtained by the differential arrival-time method clearly show that $CO_2$ migration behaviour is more complex when $CO_2$ flows normal to the bedding plane than when it flows parallel to bedding. We also found that the differences in P-wave velocity images were associated both with the $CO_2$ phases and with heterogeneity of pore distribution in the rocks. Seismic images showed that the highest velocity reduction occurred for supercritical $CO_2$ injection, compared with gaseous or liquid $CO_$ injection. This result may justify the use of the seismic method for $CO_2$ monitoring in geological sequestration.

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

• The Journal of the Korea Contents Association
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• v.8 no.4
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• pp.63-70
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• 2008

This paper presents a method of PRI do-interleaving for LASER pulse signals. When the PRI of LASER pulse is periodically changed, the first deviation and the second deviation of TOA is used to calculate the PRI pattern of input LASER signals of receiver. If the standard deviation of the first difference of TOA is less than 5% of the average of the first difference of TOA, the PRI pattern of LASER signal is fixed or jittered type. If the standard deviation is larger than 5% of the average, those are triangular PRI patterns or sawtooth PRI patterns.

• Journal of the Economic Geographical Society of Korea
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• v.11 no.2
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• pp.192-202
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• 2008

Typical activity-based travel analysis has been focused on passenger travel using household survey data. The current research focuses on freight transport using one-day travel survey data. Passenger travel can be seen as the outcome of traveller's subjective decision-making, whereas freight transport is the outcome of shipper or transport company's optimized scheduling. The research conducts an activity-based analysis of freight-vehicle trip chains. In particular, the research focuses on the difference in travel pattern between shipper-oriented private vehicle and transport company-oriented business vehicle. The research analyzed the travel diary of freight vehicles collected as part of the third national logistic survey in 2005. The diary is freight driver's one-day travel record including the information of loading capacity, item transported, destination, arrival time, etc. The analysis results show the difference between private and business vehicles in the travel pattern regarding the sequences of destination, destination type and item transported and the multi-dimensional information of the three sequences.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.6
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• pp.81-91
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• 2008

In this study, data collection delay time generated in bus information system is analysed and improvement on system reliability by minimizing the delay time is suggested. To minimize the data collection delay time (call setup time), factors on data collection phase are analyzed. Each connecting time that it occurs from wireless communication during data collection phase, is selected as a main effective variable and a model for selecting an optimum communication point to minimize the effect of data delay time by each connecting time is suggested. In this model, minimization of the point between the time carrying out wireless communication and vehicle moving time, is calculated and the difference between the bus arrival time and information delivered time to the passenger is reduced. The test results for the proposed model in BIS using a CDMA (Code Division Multiple Access) communication show that delay time in real system operation has been improved. The minimum data collection delay time based on optimal communication position leads to the better reliability for Bus Information System. This study can be applied to the selection of optimal communication position and detection position instead of empirical methods.

• Journal of The Korean Society of Clinical Toxicology
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• v.2 no.2
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• pp.90-95
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• 2004

Purpose: The purpose of this study is to compare the toxicologic characteristics of two groups of patients with acute intoxication for two different time periods and to make recommendations based on the results of this study. Methods: We reviewed retrospectively the medical records of patients with acute intoxication in our emergency center from June 1997 to May 1998 (group A) and from June 2000 to May 2003 (group B), and we evaluated differences in the epidemiologic and the toxicologic characteristics between the two groups. Results: The ratios of the number of patients with acute intoxication to the total numbers of patients who visited our emergency department were $0.49\%$ and $0.52\%$ for groups A and B, respectively. In both groups many poisoned patients visited our emergency center from 4:00 pm to midnight. The interval between the time of intoxication and arrival at the hospital was significantly shorter in group B. The number of patients transferred to our emergency center was larger in group B. Attempted suicide was the major cause of acute intoxication in both groups. Major toxic substances in both groups were centrally active drugs and insecticides. The number of comatose and mechanically ventilated patients was larger in group B. However, there was no statistically significant difference in the mortality rates. Conclusion: Emergency physicians who manage intoxicated patients should recognize regional characteristics and differences in the toxicologic characteristics of poisoning. In addition, the establishment of a poisoning control center in the regional emergency center is necessary to integrate data control and to enhance specialized management of intoxicated patients.

• Clinical and Experimental Emergency Medicine
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• v.5 no.4
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• pp.272-277
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• 2018

Objective While the effect of typhoons on emergency medicine has been evaluated, data are scarce on their effects on the emergency medical service (EMS). This study evaluated the effect of typhoons on EMS patients and performance. Methods The study period was January 2010 to December 2012. Meteorological data regarding typhoons were provided by the Korean Meteorological Administration. EMS data were retrieved from the EMS database of the national emergency management agency. The database includes ambulance run sheets, which contain clinical and operational data. In this case-crossover study, the cases and controls were EMS calls on the day of typhoon warnings and calls one week prior to the typhoon warnings, respectively. Results During the study period, 11 typhoons affected Korea. A total of 14,521 cases were selected for analysis. Overall, there were no obvious differences between the case and control groups. However, there were statistically significant differences in age, place, and time requests. There were fewer patients between 0 and 15 years of age (P=0.01) and more unconscious patients (P=0.01) in the case group. The EMS operational performance, as measured by the times elapsed between call to start, call to field, and call to hospital did not differ significantly. There was also no significant difference in the time from hospital arrival between the cases (28.67, standard deviation 16.37) and controls (28.97, standard deviation 28.91) (P=0.39). Conclusion Typhoons did not significantly affect the EMS system in this study. Further study is necessary to understand the reasons for this finding.

• Quality Improvement in Health Care
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• v.21 no.2
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• pp.12-24
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• 2015

Purpose: The need for the rapid evaluation and treatment of emergency department patients with major trauma is essential. A computerized physician order entry (CPOE) system can improve communication and provide immediate access to information with the goal of reducing ED time delays. The aim of this study was to report on the operation of a trauma CPOE program and demonstrate its usefulness by comparing time intervals from ED arrival to various evaluation steps before and after implementation of the program. Methods: This was a before-and-after observational study from a single emergency department at an academic center. The CPOE program was implemented for 6 months and compared with the data collected from the pre-CPOE implementation period. The efficacy of the program was assessed by comparing the time difference before and after CPOE implementation based on the following factors: total boarding time in ED, door-to-disposition decision time, door-to-blood-test report time, door-to-X-ray time, door-to-CT time, and door-to-transfusion time. Results: Over a period of 6 months, the CPOE was activated for a total of 17 patients. Total boarding time was reduced significantly after implementation [median, 641.5 minutes (IQR, 367.3-859.3) versus289.0 minutes (IQR, 140.0-508.0) for pre-CPOE vs. post-CPOE, respectively, p< 0.05). Time intervals for all evaluation steps were reduced after implementation of the program. The improvements in the door-to-blood-test and door-to-CT times were both statistically significant. Conclusion: This study demonstrated that a standard CPOE system can be successfully implemented and can reduce ED time delays in managing trauma patients.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.4
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• pp.160-167
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• 2021

Seabed deformation due to the fault failure have both a spatial variation and temporal history. When the faulting process initiates at a certain point beneath seabed, the failure spreads out to neighboring points, resulting in temporal changes of deformation. In particular, such a process induces tsunami waves from the vertical motion of seabed. The uprising speed of seabed affects the formation of initial surface profile, eventually altering the arrival time and runup of tsunamis at the coast. In this work, we developed a numerical model that can simulate the generation and propagation of tsunami waves by considering the horizontal and vertical changes of seabed in an active and dynamic manner. For the verification of the model, it was applied to the 2011 Tohoku-oki earthquake in Japan and the results confirmed that the accuracy was improved compared to the existing passive and static model.