• Nuclear Engineering and Technology
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• v.45 no.5
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• pp.613-624
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• 2013

Multi-dimensional two-phase phenomena occur in many industrial applications, particularly in a nuclear reactor during steady operation or a transient period. Appropriate modeling of complicated behavior induced by a multi-dimensional flow is important for the reactor safety analysis results. SPACE, a safety analysis code for thermal hydraulic systems which is currently being developed, was designed to have the capacity of multi-dimensional two-phase thermo-dynamic phenomena induced in the various phases of a nuclear system. To validate the performance of SPACE, a two-dimensional two-phase flow test was performed with slab geometry of the test section having a scale of $1.43m{\times}1.43m{\times}0.11m$. The test section has three inlet and three outlet nozzles on the bottom and top gap walls, respectively, and two outlet nozzles installed directly on the surface of the slab. Various kinds of two-dimensional air/water flows were simulated by selecting combinations of the inlet and outlet nozzles. In this study, two-dimensional two-phase void fraction profiles were quantified by measuring the local gap impedance at 225 points. The flow conditions cover various flow regimes by controlling the flow rate at the inlet boundary. For each selected inlet and outlet nozzle combination, the water flow rate ranged from 2 to 20 kg/s, and the air flow rate ranged from 2.0 to 20 g/s, which corresponds to 0.4 to 4 m/s and 0.2 to 2.3 m/s of the superficial liquid and gas velocities based on the inlet port area, respectively.

• Journal of Korean Clinical Nursing Research
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• v.19 no.3
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• pp.345-356
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• 2013

Purpose: To provide clear estimates of the adoption and use of electronic nursing records (ENRs) with standard terminology in Korea and identification of the scope and use as well as perceived or potential benefits of ENRs. Methods: A survey was done of 733 hospitals at three levels: tertiary advanced hospitals, general hospitals, and community hospitals. After performing a literature review a modified version of an existing survey tool was used for 2 months in 2012. The collected information related to EHR functionality and coverage of nursing documentation and nursing process, application of standard terminology, and perceived satisfaction and benefits of ENRs. Results: The response rate was 39.4% (289/733), and 202 hospitals (70.1%, 95% CI64.8~75.5%) of the respondents had ENR systems (82.5% of tertiary hospitals, 66.7% of general hospitals, and 70.1% of community hospitals). Out of these hospitals less than 10% had ENRs fully covering nursing documentation. The adoption rate of standard terminology was 55%, and hospital satisfaction with ENRs was 70%. But personalized care was identified as needing improvement in ENRs. Conclusion: The ENR adoption rate was high but there are many potential opportunities for improving ENR systems in terms of the data standardization and personalized care.

• The Korean Journal of Emergency Medical Services
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• v.20 no.2
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• pp.127-144
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• 2016

Purpose: The purpose of this study was to investigate the drinking behavior of university students in Jeju for the safe campus life. Methods: A self-reported questionnaire was completed by 549 students in 4 universities in Jeju. The data were analyzed by t-test, one way ANOVA, and multiple regression using SPSS Win 19.0 program. The questionnaire instruments consisted of Alcohol Use Disorders of Identification Test-Korea (AUDIT-K) and Life Stress Scale for College Students adapted by Chon. Results: The alcohol consumption rate of participants accounted for 96.2%. The binge drinking rate in female students were 33.9% and that in male students was 29.5%. The result by scoring AUDIT showed that 30.7% of participants were normal drinking group, 36.0% were hazardous drinking group, and 33.3% were estimated alcohol abuse group. The average score of stress was 1.45 by Likert 4 point scale. The female students tended to have more stresses than male. The most important influencing factors on drinking behavior were the first alcohol drinking(${\beta}=-.250$, p< .001), gender(${\beta}=.202$, p< .001), and relationship problem(${\beta}=.116$, p < .05). Conclusion: The drinking rate of university students revealed higher than that in other age groups. So the early systematic education is strongly recommended to prevent the physical and mental side effects.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7B
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• pp.868-877
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• 2011

In this paper, the feasibility of ORBCOMM satellite-based automatic identification system (SAT-AIS) is evaluated in the context of ship AIS slot collision probability depending on reporting rate, We evaluate detection probability evaluation of ORBCOMM satellite-based AIS considering link budget, SOTDMA protocol and satellite's swath width. The simulation determines the total number of vessels served by ORBCOMM satellite according to satellite's swath width, AIS slot allocation and reporting rate. By simulation results, the ORBCOMM satellite-based AIS slot collision is increased directly proportional to the total number of vessels and the more detection probability evaluation of ORBCOMM satellite-based AIS degrader, the more sip AIS reporting rate shorter.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.9
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• pp.2121-2128
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• 2015

In this paper presents a method of extracting reliable and regions of interest (ROI) in barcode for the purpose of factory automation. backgrounds are separated based on directional components and the characteristics of detected patterns. post-processing is performed on candidate images with analysis of problems caused by blur, rotation and areas of high similarity. In addition, the resizing factor is used to achieve faster calculations through image resizing. The input images contained multiple product or barcode for application to diverse automation environments; a high extraction success rate is accomplished despite the maximum shooting distance of 80 cm. Simulations involving images with various shooting distances gave an ROI detection rate of 100% and a post-processing success rate of 99.3%.

• Korean Journal of Ecology and Environment
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• v.48 no.3
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• pp.188-194
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• 2015

River channel dredging and riparian development have been influenced morphology and quantity of natural river habitat. We compared distribution of riverside land and alluvial island in the Nakdong River with field survey and remote sensing analysis after the 4 Large River Project in South Korea. We digitized geomorphological elements, includes main channel, riverside land, and alluvial island by using georeferenced aerial photos taken in pre-dredging (2008) and post-dredging (2012) periods. Field survey was followed in 2012 for a ground truth of digitized boundaries and identification of newly constructed wetland types such as pond, channel, branch, and riverine type. We found that during the dredging period, riverside land and alluvial island were lost by 20.2% and 72.7%, respectively. Modification rate of riverside land was higher in the section of river kilometer 50~90, 140~180, and 210~270. Alluvial island had higher change rate in the section of river kilometer 50~70, 190~210, and 270~310. Average change rate for the riverside land and alluvial island was $-1.02{\pm}0.14km^2{\cdot}10km^{-1}$ and $-0.05{\pm}0.05km^2{\cdot}10km^{-1}$, respectively. Channel shaped wetlands (72.5%) constituted large portion of newly constructed wetlands.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.1002-1006
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• 2002

Germination method was used to screen the biological changes in soybean, kidney bean, and red bean caused by gamma irradiation. Beans were irradiated at 0.1, 0.3, 0.5, 0.7, and 1.0 kGy. Ten beans of each sample were placed on moistened cotton and germinated at $30{\circ}C$. The root lengths were measured daily for 5 days. Root lengths of all beans grew continuously for 5 days, but the growth rate of irradiated beans decreased significantly from fourth day. Unirradiated beans showed the highest growth rate during 5 days of germination. Gamma-irradiated beans could be screened by measuring the daily growth rate and root length during germination.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.2
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• pp.215-220
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• 2009

LR-WPAN(Low-Rate Wireless Personal Area Network) hewn as IEEE 802.15.4 is considered as one of the most suitable specifications published until now to accomplish USN(Ubiquitous Sensor Network). In this paper we simulate interference effects to other systems if LR-WPAN will be used in 900MHz. In considering the current usage situation of 900MHz frequency band, we can think LR-WPAN shares the frequency band of $908.5{\sim}914MHz$ assigned for RFID/USN. The simulation results of the case of LR-WPAN and RFID/USN sharing the frequency band show that the probability of interference of LR-WPAN to CT1 and RFID is 2.5% and 2.1%, respectively. In order to avoid interference effects to public communications, simulations results show that the protection distance of about loom is needed.

• Journal of Korean Medical Science
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• v.33 no.43
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• pp.239.1-239.12
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• 2018

Background: We described a novel multi-step retinal fundus image reading system for providing high-quality large data for machine learning algorithms, and assessed the grader variability in the large-scale dataset generated with this system. Methods: A 5-step retinal fundus image reading tool was developed that rates image quality, presence of abnormality, findings with location information, diagnoses, and clinical significance. Each image was evaluated by 3 different graders. Agreements among graders for each decision were evaluated. Results: The 234,242 readings of 79,458 images were collected from 55 licensed ophthalmologists during 6 months. The 34,364 images were graded as abnormal by at-least one rater. Of these, all three raters agreed in 46.6% in abnormality, while 69.9% of the images were rated as abnormal by two or more raters. Agreement rate of at-least two raters on a certain finding was 26.7%-65.2%, and complete agreement rate of all-three raters was 5.7%-43.3%. As for diagnoses, agreement of at-least two raters was 35.6%-65.6%, and complete agreement rate was 11.0%-40.0%. Agreement of findings and diagnoses were higher when restricted to images with prior complete agreement on abnormality. Retinal/glaucoma specialists showed higher agreements on findings and diagnoses of their corresponding subspecialties. Conclusion: This novel reading tool for retinal fundus images generated a large-scale dataset with high level of information, which can be utilized in future development of machine learning-based algorithms for automated identification of abnormal conditions and clinical decision supporting system. These results emphasize the importance of addressing grader variability in algorithm developments.

• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3406-3412
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• 2021

A real-time digital time-stamp sorting algorithm used in the In-Beam positron emission tomography (In-Beam PET) is presented. The algorithm is operated in the field programmable gate array (FPGA) and a small amount of registers, MUX and memory cells are used. It is developed for sorting the data of annihilation event from front-end circuits, so as to identify the coincidence events efficiently in a large amount of data. In the In-Beam PET, each annihilation event is detected by the detector array and digitized by the analog to digital converter (ADC) in Data Acquisition Unit (DAQU), with a resolution of 14 bits and sampling rate of 50 MS/s. Test and preliminary operation have been implemented, it can perform a sorting operation under the event count rate up to 1 MHz per channel, and support four channels in total, count rate up to 4 MHz. The performance of this algorithm has been verified by pulse generator and ²²Na radiation source, which can sort the events with chaotic order into chronological order completely. The application of this algorithm provides not only an efficient solution for selection of coincidence events, but also a design of electronic circuit with a small-scale structure.