• Korean Journal of Heritage: History & Science
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• v.48 no.1
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• pp.148-165
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• 2015

Iron was one of the most influential factors for formation and development of ancient countries. The diffusion of ironware had increased agricultural productivity and brought about military technical revolution. Needless to say, the rise and fall of the countries depended on the possession of stable iron production. Raw materials and fuels are the key factors for mass production of iron and a transportation route is essential to supply the goods. Jungwon area satisfies the three factors. There are many iron manufacture sites such as Jincheon Seokjang-ri Gusan-ri, and Chunju Chilgeum-dong Tangeumdae earthen ramparts in the Jungwon area. In order to study the ancient iron manufacture technique, reconstitution experiment was carried out using restored furnace which was made based on the Jincheon Seokjang-ri B-23 furnace. Some notable results were identified with the experiment as in the followings. Firstly, a roasting process has a connection with the decrease of hardness of the iron ore. Secondly, melting of the blast pipe as well as the formation of product within the furnace had a crucial effect on the cessation of the experiment. Thirdly, reduced iron in various locations within the furnace prove that there was enough reducing environment during the working. Not only melting point but also properties of iron can vary depending on the carbon contents. For the reason, formation of approximate environment in which iron can react to the chalcoal is the most important factor in terms of iron manufacture.

• Journal of Internet Computing and Services
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• v.20 no.1
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• pp.87-96
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• 2019

In this paper, we propose a MapReduce-supported clustering technique for collecting and classifying distributed workflow enactment event logs as a preprocessing tool. Especially, we would call the distributed workflow enactment event logs as Workflow BIG-Logs, because they are satisfied with as well as well-fitted to the 5V properties of BIG-Data like Volume, Velocity, Variety, Veracity and Value. The clustering technique we develop in this paper is intentionally devised for the preprocessing phase of a specific workflow process mining and analysis algorithm based upon the workflow BIG-Logs. In other words, It uses the Map-Reduce framework as a Workflow BIG-Logs processing platform, it supports the IEEE XES standard data format, and it is eventually dedicated for the preprocessing phase of the ${\rho}$-Algorithm that is a typical workflow process mining algorithm based on the structured information control nets. More precisely, The Workflow BIG-Logs can be classified into two types: of activity-based clustering patterns and performer-based clustering patterns, and we try to implement an activity-based clustering pattern algorithm based upon the Map-Reduce framework. Finally, we try to verify the proposed clustering technique by carrying out an experimental study on the workflow enactment event log dataset released by the BPI Challenges.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.163-169
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• 2019

This study examined whether industry-level competition affects excess stock returns because of changes in cash holdings. Competitive inter-company threats increase the possibility of the manager's replacement, and function to induce management to make their best efforts, resulting in the amount and quality of the information provided by the enterprise increasing. Therefore, as competition intensifies, agency problems are reduced and stock returns increase because the company's cash holdings are expected to increase. However, there is a view that firms in industries with severe competition tend to have high information asymmetry because competitors may compete in more favorable positions by using detailed information disclosed by the competing firms. Accordingly, as market competition intensifies, the excess stock returns resulting from increased cash holdings are expected to decline. These results show that excess stock returns because of increases in cash holdings increase as the degree of competition in the industry intensifies, thus supporting the positive effect of market competition. Overall, the results of this study provide an understanding that market competition plays an effective external governance mechanism and that investors positively evaluate the cash held by companies with severe industry competition.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.169-178
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• 2021

This study is a qualitative study to explore the experiences of nursing students' psychological nursing practice in-school. The subjects of this study were 62 students who were the 3rd grade nursing students at a University in Gangwon-do. The data were collected from August 3rd to August 20th, 2020. For data analysis, Colaizzi's qualitative analysis method was applied. Six categories were derived from data analysis: 1) Lingering affection for clinical practice in field. 2) Achievement through learning 3) Fear of nurse's role in future 4) Burden for many tasks 5) Feeling free of stress from clinical practice in field 6) Importance of cooperation with other departments. The positive aspects of in-school practice education, which from nursing students' evaluation, were immediate feedback, detailed explanations, and indirect experiences. Based on this study result, it is recommended to develop in-school nursing practice education program for gap-reducing with clinical practice. It would be consisted of various contents: simulation, online/non-face-to-face practice, face-to-face practice for indirect experience. In addition, these multi-aspect effort is needed more in psychological nursing practice education to reduce the gap with clinical practice such as therapeutic communication and hallucination interventions.

• Tunnel and Underground Space
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• v.31 no.1
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• pp.52-65
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• 2021

In this study, authors analyzed the vapor cloud explosion induced by propane leak at the PEMIX Terminal, which is the propane storage facility outside of Mexico City. TNT equivalence mass for the leaked 4750 kg propane was estimated to be 9398 kg. Blast parameters such as peak overpressure, positive phase duration, and impact at 40-400 (m) away from the center of the explosion were calculated by applying TNT Equivalency Method and Multi-Energy Method. The probability of damage due to lung damage, eardrum rupture, head impact, and whole-body displacement impact by applying the probit function obtained using blast parameters was evaluated. The peak overpressure obtained using Multi-Energy Method was found to be greater than the peak overpressure obtained by applying the TNT Equivalency Method at all distances considered, but it was evaluated that there was no significant difference from the points above 200 m. The peak overpressure obtained by Multi-Energy Method was computed to assess the extent of damage to the structure, and it was shown that structures within 100 m of the explosion center would collapse completely, and that the glasses of the structures 400 m away would be almost broken. The probability of death due to lung damage was shown to vary depending on a human body's position located in the propagating direction of shock wave, and if there is a reflecting surface in the immediate surroundings of a human body, the probability of death was estimated to be the greatest. The impact of shock wave on lung damage, eardrum rupture, head impact, and whole-body displacement impact was evaluated and found to affect whole-body impact < lung damage < eardrum rupture

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.2
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• pp.95-106
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• 2021

Side-jets enable the immediate maneuver of a missile compared to control surfaces; however, they may cause adverse effects on aerodynamic coefficients, for they interfere with freestream. To find out the impact of side-jets on aerodynamic coefficients, we simulate side-jets as air gas and utilize multi-fidelity models to evaluate differences between aerodynamic coefficients obtained with and without side-jets. We computed differences in aerodynamic coefficients to investigate side-jet effects for the changes of a Mach number, a bank angle, and an angle of attack. As a result, asymmetrically developed side-jets affect the longitudinal force and moment coefficients, and the lateral force and moment coefficients drastically change in-between -30 and 30 degrees of bank angles. In contrast, side-jets hardly influence the axial force coefficients. As for the axial moment coefficient, we could not determine the side-jet effect due to a lack of aerodynamic coefficient samples in the Mach number. All in all, we confirm that side-jets lead to the change of a missile attitude as they considerably vary the longitudinal and lateral aerodynamic coefficients.

• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.577-589
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• 2021

Drone mapping systems can be applied to many fields such as disaster damage investigation, environmental monitoring, and construction process monitoring. To integrate individual sensors attached to a drone, it was essential to undergo complicated procedures including time synchronization. Recently, a variety of composite sensors are released which consist of visual sensors and GPS/INS. Composite sensors integrate multi-sensory data internally, and they provide geotagged image files to users. Therefore, to use composite sensors in drone mapping systems, mapping accuracies from composite sensors should be examined. In this study, we analyzed the mapping accuracies of a composite sensor, focusing on the data acquisition area and pre-calibration effect. In the first experiment, we analyzed how mapping accuracy varies with the number of ground control points. When 2 GCPs were used for mapping, the total RMSE has been reduced by 40 cm from more than 1 m to about 60 cm. In the second experiment, we assessed mapping accuracies based on whether pre-calibration is conducted or not. Using a few ground control points showed the pre-calibration does not affect mapping accuracies. The formation of weak geometry of the image sequences has resulted that pre-calibration can be essential to decrease possible mapping errors. In the absence of ground control points, pre-calibration also can improve mapping errors. Based on this study, we expect future drone mapping systems using composite sensors will contribute to streamlining a survey and calibration process depending on the data acquisition circumstances.

• Journal of the Korean GEO-environmental Society
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• v.12 no.1
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• pp.51-60
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• 2011

Electrical resistivity is applied for understanding details about layers and obtaining basic properties of soils to various measurement devices. The objective of this study is development of TRP(Temperature-compensated Resistivity Probe), analysis about effects of temperature changes during cone penetration test, and observation of characteristics of cone penetration. In order to observation of temperature changes according to a diameter difference of resistivity cone probe, the cone which has wedge type cone tip is made to two types, 2mm and 5mm. Temperature sensor is attached at 15mm below from cone tip because of an electrical interference with elecrical resistance probe. Delectrical connector is used to prevent electric disturbance between motor type penetrating machine and electrical resistivity cone probe. Application tests are carried out in acrylic cell whose diameter is 30cm with uniform Jumunjin sand according to densification caused by blows. The test results indicate that the temperature is increased uniformly during penetration and a tendency, characteristics of cone penetration, is discovered during altering state of soils. This study suggests that the temperature effects and characteristics of penetration should be considered in penetrating tests in order to conduct an accurate ground investigation using TRP(Temperature-compensated Resistivity Probe).

• Journal of Apiculture
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• v.32 no.3
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• pp.163-170
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• 2017

Small hive beetle (SHB, Aethina tumida Murray (Coleoptera: Nitidulidae) is a honeybee pest infesting combs and stores inside the hive. Contamination of the SHB on Apis mellifera colonies were firstly noticed on September 23, 2016, in Miryang City, Gyeongnam Province in Korea. After that, on October 5, 2016, we investigated the spatial distribution of SHB inside the hive and outside soil within the apiary. Total of 169 beehives were observed. We found all stages of SHB inside or outside of hives. 61% of hives infested with the adult SHB still had live honeybees whereas hives containing larval SHB did not have bees, implying colony destruction In hives with live bees, infestation density was higher as bee population became higher. Coefficient of dispersions (CD) showed significant clumped distribution of infestation among hives. CDs were much higher inside hive than outside soil. Our results indicates SHB could result in honeybee colony collapse it not managed properly. Also even during October, there are new infestation into honeybee colonies and every stage of SHB could still be able to develop. Further detailed analysis of this insect' adaptation in Koran environment could help guide the management strategies of the invaded new pest of honeybee.

• (The)Study of the Eastern Classic
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• no.33
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• pp.159-191
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• 2008

This study aims to look into the three-dimensional characteristics of Euniljisa (a scholar who lived in a hidden place) demonstrated in the poems of Myeongam Jeong-Sik (1683-1746, the 9th year of King Sukjong to the 22nd year of King Yeongjo), who was a scholar in the region of Yeongnam in the 18th century. Myeongam Jeongsik had a very righteous aspect in terms of integrity. He was born about 40 years after the Ching Dynasty was established. However, as shown in his pen name of 'Myeongam', he still used the Ming Dynasty as a subject of adoration and reverence, and he lived as an integral man of scholarly virtue in seclusion while refusing to have a government post during his lifetime. In his poems, there may be various discussions, but this study focused on following two aspects. First, the study reviewed his attitude toward the world, that is a retiring attitude, in looking into his works. Second, the study did not merely keep the existing two-dimensional perspective in simply reviewing a hermitage poem in the analyzing of a poem. Instead, the study attempted a three-dimensional review in seeking to see whether three items involving the fidelity and integrity of a dignified and daring person (a person who does not care about worldly views), the ambivalent emotion of Jo Wul reflected in the poem, and the delicate description and the expression of emotions, are placed in a serial relationship.