• Nuclear Engineering and Technology
• /
• v.53 no.9
• /
• pp.3068-3084
• /
• 2021

Investigations of large commercial aircraft impact effect on nuclear power plant (NPP) buildings have been drawing extensive attentions, particularly after the 9/11 event, and this paper aims to experimentally assess the damage and vibrations of NPP buildings subjected to aircraft crash. In present Part I, two shots of reduce-scaled model test of aircraft impacting on NPP building were carried out. Firstly, the 1:15 aircraft model (weighs 135 kg) and RC NPP model (weighs about 70 t) are designed and prepared. Then, based on the large rocket sled loading test platform, the aircraft models were accelerated to impact perpendicularly on the two sides of NPP model, i.e., containment and auxiliary buildings, with a velocity of about 170 m/s. The strain-time histories of rebars within the impact area and acceleration-time histories of each floor of NPP model are derived from the pre-arranged twenty-one strain gauges and twenty tri-axial accelerometers, and the whole impact processes were recorded by three high-speed cameras. The local penetration and perforation failure modes occurred respectively in the collision scenarios of containment and auxiliary buildings, and some suggestions for the NPP design are given. The maximum acceleration in the 1:15 scaled tests is 1785.73 g, and thus the corresponding maximum resultant acceleration in a prototype impact might be about 119 g, which poses a potential threat to the nuclear equipment. Furthermore, it was found that the nonlinear decrease of vibrations along the height was well reflected by the variations of both the maximum resultant vibrations and Cumulative Absolute Velocity (CAV). The present experimental work on the damage and dynamic responses of NPP structure under aircraft impact is firstly presented, which could provide a benchmark basis for further safety assessments of prototype NPP structure as well as inner systems and components against aircraft crash.

• Journal of Yeungnam Medical Science
• /
• v.38 no.4
• /
• pp.337-343
• /
• 2021

Background: Chromogranin A (CgA) levels have been reported to predict mortality in patients with heart failure. However, information on the prognostic value and clinical availability of CgA is limited. We compared the prognostic value of CgA to that of previously proven natriuretic peptide biomarkers in patients with acute heart failure. Methods: We retrospectively evaluated 272 patients (mean age, 68.5±15.6 years; 62.9% male) who underwent CgA test in the acute stage of heart failure hospitalization between June 2017 and June 2018. The median follow-up period was 348 days. Prognosis was assessed using the composite events of 1-year death and heart failure hospitalization. Results: In-hospital mortality rate during index admission was 7.0% (n=19). During the 1-year follow-up, a composite event rate was observed in 12.1% (n=33) of the patients. The areas under the receiver-operating characteristic curves for predicting 1-year adverse events were 0.737 and 0.697 for N-terminal pro-B-type natriuretic peptide (NT-proBNP) and CgA, respectively. During follow-up, patients with high CgA levels (>158 pmol/L) had worse outcomes than those with low CgA levels (≤158 pmol/L) (85.2% vs. 58.6%, p<0.001). When stratifying the patients into four subgroups based on CgA and NT-proBNP levels, patients with high NT-proBNP and high CgA had the worst outcome. CgA had an incremental prognostic value when added to the combination of NT-proBNP and clinically relevant risk factors. Conclusion: The prognostic power of CgA was comparable to that of NT-proBNP in patients with acute heart failure. The combination of CgA and NT-proBNP can improve prognosis prediction in these patients.

• Journal of the Korea Convergence Society
• /
• v.12 no.12
• /
• pp.315-322
• /
• 2021

This study analyzes the Required Safe Egress Time (RSET), in the event of a fire at a welfare center for the disabled, using the emergency passage according to the floor arrangement of users to evaluate the safety and the difference in RSET for each emergency passage using the Pathfinder simulation program to suggest an efficient evacuation method. As a result of RSET, it was found that there is no problem in evacuation safety for the current state of the facility's personnel allocation by satisfying the standard RSET in case of fire, and evacuation can be completed safely by evacuating through stairs rather than using elevators if possible. It is necessary for employees to be provided sufficient education and training in advance so that they can evacuate effectively with the disabled in case of fire. This study gives significance in saving many precious lives and safely evacuate in case of fire as evacuation routes were secured through the design, construction and operation of facilities for the disabled and the RSET was shortened through regular evacuation practices. It is necessary to discuss the further RSET studies based on the automatic fire shutters open or not when a fire occurs at a specific location following the installation of automatic fire shutter at the entrance of each floor of the facilities.

• Journal of the Korean Society of Radiology
• /
• v.15 no.6
• /
• pp.849-853
• /
• 2021

PET images used in medical diagnoses are created using positron emitting radionuclides. The radiation used for imaging is generated at 0.511 MeV by p-annihilation. The CSDA range is the distance the particle radiation flew physically, and it is different from the range shown in PET images. This study proposes a novel method that uses radiological criteria to measure this range. The experiment was conducted by applying the MCNP6 simulation to positron emitting nuclides ¹⁸F, ¹¹C, ¹³N, and ¹⁵O. Radiological criteria were based on the location of the p-annihilation event, which is also the image signal. Results showed the radiological range of positrons to be 2.3, 3.9, 5.0, and 7.9 mm for ¹⁸F, ¹¹C, ¹³N, and ¹⁵O, respectively. The higher the positron energy, the larger its difference from the CSDA range. Positron emitting nuclide is being developed and studied as a nuclide for dosimetry or radiotherapy. Further research needs to be conducted into various positron ranges.

• Journal of Korea Water Resources Association
• /
• v.54 no.5
• /
• pp.321-334
• /
• 2021

A fixed reflectivity-rainfall relationship approach, such as the Marshall-Palmer relationship, for an entire year and different seasons, can be problematic in cases where the relationship varies spatially and temporally throughout a region. From this perspective, this study explores the use of long-term radar reflectivity for South Korea to obtain a nationwide calibrated Z-R relationship and the associated uncertainties within a Bayesian inference framework. A calibrated spatially structured pattern in the parameters exists, particularly for the wet season and parameter for the dry season. A pronounced region of high values during the wet and dry seasons may be partially associated with storm movements in that season. Overall, the radar rainfall fields based on the proposed modeling procedure are similar to the observed rainfall fields. In contrast, the radar rainfall fields obtained from the existing Marshall-Palmer relationship show a systematic underestimation. In the event of high impact weather, it is expected that the value of national radar resources can be improved by establishing an active watershed-level hydrological analysis system.

• Ocean and Polar Research
• /
• v.43 no.4
• /
• pp.307-320
• /
• 2021

Udo Rhodolith Beach is a small-scale, mixed sand-and-gravel beach embayed on the N-S trending rocky coast of Udo, Jeju Island, South Korea. This study analyzes the short-term topographic changes of the beach during the extreme storm conditions of four typhoons from 2016 to 2020: Chaba (2016), Soulik (2018), Lingling (2019), and Maysak (2020). The analysis uses the topographic data of terrestrial LiDAR scanning and drone photogrammetry, aided by weather and oceanographic datasets of wind, wave, current and tide. The analysis suggests two contrasting features of alongshore topographic change depending on the typhoon pathway, although the intensity and duration of the storm conditions differed in each case. During the Soulik and Lingling events, which moved northward following the western sea of the Jeju Island, the northern part of the beach accreted while the southern part eroded. In contrast, the Chaba and Maysak events passed over the eastern sea of Jeju Island. The central part of the beach was then significantly eroded while sediments accumulated mainly at the northern and southern ends of the beach. Based on the wave and current measurements in the nearshore zone and computer simulations of the wave field, it was inferred that the observed topographic change of the beach after the storm events is related to the directions of the wind-driven current and wave propagation in the nearshore zone. The dominant direction of water movement was southeastward and northeastward when the typhoon pathway lay to the east or west of Jeju Island, respectively. As these enhanced waves and currents approached obliquely to the N-S trending coastline, the beach sediments were reworked and transported southward or northward mainly by longshore currents, which likely acts as a major control mechanism regarding alongshore topographic change with respect to Udo Rhodolith Beach. In contrast to the topographic change, the subaerial volume of the beach overall increased after all storms except for Maysak. The volume increase was attributed to the enhanced transport of onshore sediment under the combined effect of storm-induced long periodic waves and a strong residual component of the near-bottom current. In the Maysak event, the raised sea level during the spring tide probably enhanced the backshore erosion by storm waves, eventually causing sediment loss to the inland area.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.4
• /
• pp.473-482
• /
• 2021

The introduction of automated flight systems has greatly improved aviation safety, but aircraft pilots continue to face new challenges. The pilot's stress from an aeronautical perspective can be distinguished by the 'Startle and Surprise' responses. 'Startle' is a short, strong physiological response to sudden or threatening stimuli such as unexpected gunfire. 'Surprise' is a cognitive-emotional response to an event that goes beyond one's expectations. In Martin et al.'s (2012) Startle Effect Experiment, the pilot identified physiological responses in the 'Startle' state, including delayed response and increased heart rate. In the Rahim (2020) Startle/Surprise experiment, the pilot's breathing rate and pulse rate did not change due to pre-planned emergency training. On the other hand, it was confirmed that the pilot's respiratory and heart rate were greatly increased due to the complicated aircraft and unplanned emergencies. Based on the results of these experiments, domestic pilots need to be trained to handle non-technical and various unexpected emergencies that could arise in an aircraft, rather than be just put through courses for enhancing technical capabilities or simple repetitive training as required by aviation law.

• 교육공학연구
• /
• v.33 no.4
• /
• pp.1001-1024
• /
• 2017

Flipped classroom has used widely in university in that its unique structure can facilitate learners' higher-thinking skills and promote competencies. Learners are expected to extend knowledge through performing online and offline, but they have difficulty in understanding their roles and specific behaviors to achieve the learning goals in the flipped learning. Therefore, a guidance for students has been required to support learners' mastery learning. The purpose of this study is to identify successful learners' characteristics in terms of "competency". For this, three-phased competency modeling was employed. In Phase I, Behavioral Event Interviews were conducted with eight learners of the flipped classroom. In Phase II for identifying competencies and developing a competency model, the data was coded, followed by testing reliability of the coding. Based on the meaning codes, competencies and behavioral indexes were developed. The final competencies consist of learning orientation, learning management, feedback seeking, peer interaction, and knowledge extension. In Phase III, validation of the competency model was conducted by explanatory factor analysis. As last, competencies were aligned by the two-phase of the flipped classroom. The finding will be used as the guidance for the learners and instructors in the flipped classroom.

• Journal of Korean Theatre Studies Association
• /
• no.52
• /
• pp.5-59
• /
• 2014

This paper investigates the development and aesthetics of Korean political theatre from its quickening period 1920s to democratization era 1990s. Political theatre before 90s developed an antithesis resistant movement toward Korean modern history that had been scattered with suppressing political circumstances such as colonial era and dictatorial government, the movement has powerful activity and social influences. Just like the 20 century political theatre had been quickened under the influence of Marxism at Russia and Germany in 1920s, Korea's political theatre began in socialism theatre movement form around the same time. Proletarian theatre groups had been founded in Japan and Korea, and developed into practical movement with organized connection. However, the political theatre movement in Japanese colonial era was an empty vessel makes great sound but not much accomplishments. Most performance had been canceled or disapproved by suppression or censorship of the Japanese Empire. The political theatre in liberation era was the left drama inherited from Proletarian theatre of the colonial era. Korean Theatre alliance took lead the theatrical world unfold activities based on theatre popularization theory such as 'culture activists' taking a jump up the line and 'independent theatre' peeping into production spot as well as the important event, Independence Movement Day Memorial tournament theatre. Since 1947, US army military government in Korea strongly oppressed the left performances to stop and theatrical movement was ended due to many left theatrical people defection to North Korea. The political theatre in 1960s to 70s the Park regime, developed in dramatically different ways according to orthodox group and group out of power. The political theatre of institutional system handled judgment on sterile people and had indirect political theatre from that took history material and allegory technique because of censorship. In political theatre out of institution, it started outdoor theatre that has modernized traditional performance style and established deep relationship with labor spot and culture movement organizations. Madangguek(Outdoor theatre) is 'Attentive political theatre', satirizing and offending the political and social inconsistencies such as the dictatorial government's oppression and unbalanced distribution, alienation of general people, and foreign powers' pillage sharply as well as laughing at the Establishment with negative characters. The political theatre in 1980s is divided into two categories; political theatre of institutional system and Madangguek. Institutional Political theatre mainly performed in Korea Theatre Festival and the theatre group 'Yeonwoo-Moudae' led political theatre as private theatre company. Madangguek developed into an outdoor theatrical for indoor theatre capturing postcolonial historical view. Yeonwoo-Moudae theatre company produced representative political plays at 80s such as The chronicles of Han's, Birds fly away too, and so on by combining freewheeling play spirit of Madangguek and epic theatre. Political theatre was all the rage since the age of democratization started in 1987 and political materials has been freed from ban. However, political theatre was slowly declined as real socialism was crumbling and postmodernism is becoming the spirit of the times. After 90s, there are no more plays of ideology and propaganda that aim at politicization of theatre. As the age rapidly entered into the age of deideology, political theatre discourse also changed greatly. The concept 'the political' became influential as a new political possibility that stands up to neoliberalism system in the evasion of politics. Rather than reenact political issues, it experiments new political theatre that involves something political by deconstructing and reassigning audience's political sense with provocative forms, staging others and drawing discussion about it.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.8
• /
• pp.331-343
• /
• 2019

The purpose of this study is to observe the trends of heart age of Koreans by using the predictor of heart age of the Framingham Heart Study. The subjects were 20,012 adults aged 30~74 years who were enrolled in the Korean National Health and Nutrition Examination Survey from 2005~2013. They filled in the determinants data and they had no history of cardiovascular disease (CVD). The heart age was calculated using a non-laboratory based model of prediction. The difference of heart age and chronological age, and the rate of excessive heart age over 10 years were calculated. The annual trend, the difference according to gender, the age bracket and geographic region, the heart age were all evaluated. Data analysis performed using the SAS program (version 9.3). Complex designed analysis was done. The heart age showed differences according to gender, age bracket and geographic region. The heart age is a useful comprehensive indicator for predicting the CVD events in the near future. So, it could be used for the purposes of exercising caution and guidance on CVD for administering medical care. It is strongly recommended to use heart age as an indicator for customized medical management to focus efforts on relatively vulnerable subjects and their factors for CVD. Further study on Koreans' customized heart age is needed.