• Journal of Astronomy and Space Sciences
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• v.33 no.4
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• pp.247-256
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• 2016

An analysis of light curves and spectra of observed gamma-ray bursts in gamma-ray ranges is frequently demanded because the prompt emission contains immediate details regarding the central engine of gamma-ray bursts (GRBs). We have revisited the relationship between the collimation-corrected peak luminosity and the spectral lag, investigating the lag-luminosity relationships in great detail by focusing on spectral lags resulting from all possible combinations of channels. Firstly, we compiled the opening angle data and demonstrated that the distribution of opening angles of 205 long GRBs is represented by a double Gaussian function having maxima at ~ 0.1 and ~ 0.3 radians. We confirmed that the peak luminosity and the spectral lag are anti-correlated, both in the observer frame and in the source frame. We found that, in agreement with our previous conclusion, the correlation coefficient improves significantly in the source frame. It should be noted that spectral lags involving channel 2 (25-50 keV) yield high correlation coefficients, where Swift/Burst Alert Telescope (BAT) has four energy channels (channel 1: 15-25 keV, channel 2: 25-50 keV, channel 3: 50-100 keV, channel 4: 100-200 keV). We also found that peak luminosity is positively correlated with peak energy.

• Journal of Korean Society on Water Environment
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• v.39 no.1
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• pp.20-29
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• 2023

This study analyzed the relationship between harmful cyanobacterial abundance and environmental factors in order to figure out the causes of the recent increase of cyanobacteria in Lake Dukdong from 2019 to 2021. Lake Dukdong, which is used as a drinking water source for Gyeongju City, has an algae alert system in place. Lake Dukdong has maintained good water quality, but algae alert level 1 (over 1,000 cells/mL) has been issued in recent years. As a result of Pearson correlation analysis (from May to Oct.), the cell density of Microcystis and Aphanizomenon, which form part of the most harmful cyanobacteria genus, were significantly positively correlated with the water temperature and water storage volume. T-test was performed to compare the data from 2016-2018 and 2019-2021 (from May to Oct.). The average density of harmful cyanobacteria cells increased about six-fold from 54 to 344 cells/mL. There were significant differences in water temperature, pH, total nitrogen (TN), total phosphorus (TP), TN/TP ratio, water storage volume, and cyanobacterial cell density. Water temperature increased from 19.2 to 22.8 ℃. TP concentration increased from 0.017 to 0.028 mg/L. The main cause of the recent increase of harmful cyanobacteria in Lake Dukdong is thought to be the increase in water temperature, TP concentration, and water storage volume from 2019 and 2021, resulting in more favorable conditions for cyanobacterial growth.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.2
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• pp.69-79
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• 2017

In this study, we developed real-time urban stream discharge forecasting model using short-term rainfall forecasts data simulated by a regional climate model (RCM). The National Centers for Environmental Prediction (NCEP) Climate Forecasting System (CFS) data was used as a boundary condition for the RCM, namely the Global/Regional Integrated Model System(GRIMs)-Regional Model Program (RMP). In addition, we make ensemble (ESB) forecast with different lead time from 1-day to 3-day and its accuracy was validated through temporal correlation coefficient (TCC). The simulated rainfall is compared to observed data, which are automatic weather stations (AWS) data and Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA 3B43; 3 hourly rainfall with $0.25^{\circ}{\times}0.25^{\circ}$ resolution) data over midland of Korea in July 26-29, 2011. Moreover, we evaluated urban rainfall-runoff relationship using Storm Water Management Model (SWMM). Several statistical measures (e.g., percent error of peak, precent error of volume, and time of peak) are used to validate the rainfall-runoff model's performance. The correlation coefficient (CC) and the Nash-Sutcliffe efficiency (NSE) are evaluated. The result shows that the high correlation was lead time (LT) 33-hour, LT 27-hour, and ESB forecasts, and the NSE shows positive values in LT 33-hour, and ESB forecasts. Through this study, it can be expected to utilizing the real-time urban flood alert using short-term weather forecast.

• Convergence Security Journal
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• v.17 no.5
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• pp.27-34
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• 2017

Network security visualization technique using security alerts provide the administrator with intuitive network security situation by efficiently visualizing a large number of security alerts occurring from the security devices. However, most of these visualization techniques represent events using overlap the timelines of the alerts or Top-N analysis by their frequencies resulting in failing to provide information such as the attack trend, the relationship between attacks, the point of occurrence of attack, and the continuity of the attack. In this paper, we propose an effective visualization technique which intuitively explains the transition of the whole attack and the continuity of individual attacks by arranging the events spirally according to timeline and marking occurrence point and attack type. Furthermore, the relationship between attackers and victims is provided through a single screen view, so that it is possible to comprehensively monitor not only the entire attack situation but also attack type and attack point.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.5
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• pp.545-554
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• 1999

We would like to develop a short-term model to predict the time-related concentration of ozone whose reaction mechanism is complex. The paper targets Seoul where an ozone alert system has recently been employed. In order to develop a short-term prediction model for ozone, we suggested the Ozone Peak Indicator(OPI), an equivalent of the potential daily maximum ozone concentration, with precursors being the only limiting factor, and we calculated the Ozone Peak Indicarot as OPI={$rac{(O_3)_{max}cdot(H_{eH})_{max}(Rad)_{max}$ to preclude the influence of mixing height and solar radiation on the daily maximum ozone concentration. The OPI on the day of the prediction is to be calcultated by using the relation between OPI and the initial value of precursors. The basic prediction formula for time-related ozone concentration was established as $O_3(1)={(OPI)cdot Rad(t-2)H_{eH}}$, using the OPI, solar radiation two hours before prediction and mixing height. We developed, along with the basic formula for predicting photochemical oxidants, "SEOM"(Seoul Empirical Oxidants Model), a Fortran program that helps predict solar radiation and mixing height needed in the prediction of ozone pollution. When this model was applied to Seoul and an analysis of the correlation between the observed and the predicted ozone concentrations was made through SEOM, there appeared a very high correlation, with a coefficient of 0.815. SEOM can be described as a short-term prediction model for ozone concentration in large cities that takes into account the initial values of precursors, and changes in solar radiation and mixing height. SEOM can reflect the local characteristics of a particular and region can yield relatively good prediction results by a simple data input process.t process.

• Journal of Korean Academy of Nursing
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• v.26 no.4
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• pp.743-758
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• 1996

This paper was done to verify the use of the Profile of Mood States (POMS) which was developed by McNair, Lorr, and Droppleman(1992) with modifications so that it is appropriate for Korean elders. Through the modified tool, it is possible to examine the mood of Korean elders and to contribute to the welfare of elders. The subjects were 370 elderly persons over 60 years old and the data for 319 persons(86%) were analyzed. The research tool was the POMS translated by Yun(1993) and corrected by the researcher. Data were collected between February 12 and April 9 in 1996 and analyzed using the SAS package. The result are as follows 1. Items with low Cronbach coefficient alpha which means low correlation with total items were removed. The items were removed : friendly, tense, considerate, relaxed, sympathetic, resentful, good-natured, rebellious, trusting, carefree. 2. Overlapped or ambiguous items were discussed by colleagues and elders through verification of con-tent-validity and were removed. Five items were removed in tense-anxiety, seven, in depression-dejection, three, in vigor-activity, three, in fatigue-inertia, two, in confusion-bewilder-ment, five, in friendliness, and six, in anger-hostility. Thirty four items remainined : angry, clear-headed, lively, confused, sorry, shaky, list-less, peeved, sad, active, blue, hopeless, spiteful, uneasy, unable to concentrate, fatigued, helpful, nervous, lonely, cheerful, bitter, exhausted, anxious, ready to fight, sluggish, helpless, alert, deceived, efficient, worthless, forgetful, terrified, vigorous, and uncertain about things. 3. Factor analysis was done in order to confirm construct validity and three factors were obtained from the result. The first factor, 'anxiety-depression' included 21 items, the second factor, 'vigor' included eight items, and the third factor, 'anger' included five items. Cronbach coefficient alpha for the 34 items was. 95. Based on the result, the following is suggested : 1. a contribute to elder's welfare can be made by examining Korean elder's mood in life. 2. there is a need to develop tools appropriate to Korean culture which can be used to examine elders' mood. 3. The modified POMS tool needs to be reverified with appropriate age groups and settings.

• Journal of The Korean Society of Clinical Toxicology
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• v.6 no.2
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• pp.91-98
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• 2008

Purpose: The hypnotic effect of zolpidem is comparable to benzodiazepines, but has less abuse and addiction potential than benzodiazepines, so is one of the most commonly prescribed hypnotics. The frequency of acute zolpidem overdose has increased, but clinical analysis and severity predictors are not known in Korea. Methods: A retrospective evaluation of histories, clinical courses, and laboratory findings of each patient treated from June, 2000, to May, 2006, in a university hospital for acute zolpidem intoxication. Results: We evaluated 30 patients, including 16 co-intoxication cases. Twenty-five patients presented mental alterations but became alert within 2 days. All patients recovered completely. The median zolpidem concentration was 0.9 mg/L (range: $0.2{\sim}7.4\;mg/L$). There was a weak correlation between the amount ingested and zolpidem concentration (r=0.25). None of them presented severe laboratory abnormalities, and these abnormalities did not relate to zolpidem concentration. Conclusion: The clinical progress of acute zolpidem intoxication is mild. We could not predict zolpidem concentration or clinical severity from the amount ingested and could not predict the clinical course from laboratory findings in the emergency department.

• Journal of Broadcast Engineering
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• v.19 no.4
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• pp.491-501
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• 2014

Recently, the need for disaster-preventing broadcast has increased gradually to cope with natural disaster like earthquake and tsunami causing enormous losses of both life and property. In disaster-preventing broadcast system, the wake-up signal is used to alert user terminal and switch the current state of channel to the emergency channel, which is for the fast and efficient delivery of emergency information. In this paper, we propose the detection method of wake-up signal for disaster-preventing broadcast systems. The wake-up signals for disaster-preventing broadcast should have a good auto-correlation property in low power and narrow-band conditions that does not affect the existing digital television (DTV) system. The suitability of the m-sequence and complementary code (CC) is analyzed for wake-up signals according to signal to noise ratio. A wake-up signal is proposed by combining the direct sequence spread spectrum (DSSS) technique and pseudo noise (PN) sequences such as Barker and Walsh-Hadamard codes. By using the proposed method, a higher detecting performance can be achieved by the spreading gain compared to the single long m-sequence and the Golay code.

• Journal of The Korean Society of Clinical Toxicology
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• v.16 no.2
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• pp.61-67
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• 2018

Purpose: To evaluate the association between neutrophil-to-lymphocyte ratio (NLR) and occurrence of aspiration pneumonia in drug intoxication (DI) patients in the emergency department (ED) and to evaluate the relationship between NLR and length of hospital admission/intensive care unit (ICU) admission Methods: A total of 466 patients diagnosed with DI in the ED from January 2016 to December 2017 were included in the analysis. The clinical and laboratory results, including NLR, were evaluated as variables. NLR was calculated as the absolute neutrophil count/absolute lymphocyte count. To evaluate the prognosis of DI, data on the development of aspiration pneumonia were obtained. Also, we evaluated the relationship between NLR and length of hospital admission and between NLR and length of ICU admission. Statistically, multivariate logistic regression analyses, receiver-operating characteristic (ROC) curve analysis, and Pearson's correlation (${\rho}$) were performed. Results: Among the 466 DI patients, 86 (18.5%) developed aspiration pneumonia. Multivariate logistic regression analysis revealed NLR as an independent factor in predicting aspiration pneumonia (odds ratio, 1.7; p=0.001). NLR showed excellent predictive performance for aspiration pneumonia (areas under the ROC curves, 0.815; cut-off value, 3.47; p<0.001) with a sensitivity of 86.0% and a specificity of 72.6%. No correlations between NLR and length of hospital admission (${\rho}=0.195$) and between NLR and length of ICU admission (${\rho}=0.092$) were observed. Conclusion: The NLR is a simple and effective marker for predicting the occurrence of aspiration pneumonia in DI patients. Emergency physicians should be alert for aspiration pneumonia in DI patients with high NLR value (>3.47).