• Nuclear Engineering and Technology
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• 제45권2호
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• pp.211-218
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• 2013

Large quantities of irradiated graphite waste from graphite-moderated nuclear reactors exist and are expected to increase in the case of High Temperature Reactor (HTR) deployment [1,2]. This situation indicates the need for a graphite waste management strategy. Of greatest concern for long-term disposal of irradiated graphite is carbon-14 ($^{14}C$), with a half-life of 5730 years. Fachinger et al. [2] have demonstrated that thermal treatment of irradiated graphite removes a significant fraction of the $^{14}C$, which tends to be concentrated on the graphite surface. During thermal treatment, graphite surface carbon atoms interact with naturally adsorbed oxygen complexes to create $CO_x$ gases, i.e. "gasify" graphite. The effectiveness of this process is highly dependent on the availability of adsorbed oxygen compounds. The quantity and form of adsorbed oxygen complexes in pre- and post-irradiated graphite were studied using Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and Xray Photoelectron Spectroscopy (XPS) in an effort to better understand the gasification process and to apply that understanding to process optimization. Adsorbed oxygen fragments were detected on both irradiated and unirradiated graphite; however, carbon-oxygen bonds were identified only on the irradiated material. This difference is likely due to a large number of carbon active sites associated with the higher lattice disorder resulting from irradiation. Results of XPS analysis also indicated the potential bonding structures of the oxygen fragments removed during surface impingement. Ester- and carboxyl-like structures were predominant among the identified oxygen-containing fragments. The indicated structures are consistent with those characterized by Fanning and Vannice [3] and later incorporated into an oxidation kinetics model by El-Genk and Tournier [4]. Based on the predicted desorption mechanisms of carbon oxides from the identified compounds, it is expected that a majority of the graphite should gasify as carbon monoxide (CO) rather than carbon dioxide ($CO_2$). Therefore, to optimize the efficiency of thermal treatment the graphite should be heated to temperatures above the surface decomposition temperature increasing the evolution of CO [4].

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.248-248
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• 2023

In recent years, the number of landslides in Korea has been increasing due to extreme weather events such as localized heavy rainfall and typhoons. Landslides often occur with debris flows, land subsidence, and earthquakes. They cause significant damage to life and property. 64% of Korea's land area is made up of mountains, the government wanted to predict landslides to reduce damage. In response, the Korea Forest Service has established a 'Landslide Information System' to predict the likelihood of landslides. This system selects a total of 13 landslide factors based on past landslide events. Using the LR technique (Logistic Regression) to predict the possibility of a landslide occurrence and the accuracy is known to be 0.75. However, most of the data used for learning in the current system is on landslides that occurred from 2005 to 2011, and it does not reflect recent typhoons or heavy rain. Therefore, in this study, we will apply a total of six machine learning techniques (KNN, LR, SVM, XGB, RF, GNB) to predict the occurrence of landslides based on the data of Inje, Gangwon-do, which was recently produced by the National Institute of Forest. To predict the occurrence of landslides, it is necessary to process converting landslide events and factors data into a suitable form for machine learning techniques through ArcGIS and Python. In addition, there is a large difference in the number of data between areas where landslides occurred or not. Therefore, the prediction was performed after correcting the unbalanced data using Tomek Links and Near Miss techniques. Moreover, to control unbalanced data, a model that reflects soil properties will use to remove absolute safe areas.

• 대한의용생체공학회:의공학회지
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• 제14권4호
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• pp.321-326
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• 1993

Recently, microcomputer technology has been developed rapidly and it provides not only graphic user interface that can be fraendly accessable but also large storage capacity to han- dle much hospital information. Almost all the order communication system for hospital has been developed under the concept of host and terminal environment since last 20 years. However, host-terminal system has not been successful in korea simply because most of physicians prescibe for rrlany patients a day(sometimes more than 150 patients a day). Also, under the host-terminal environment, programs are not friendly implemented for users. Since March 1991, we had developed order communication system for out-patients(named YONSEI-PC) using personal computer(PC) and local area network(LAN) . Since September 1992, we has applied succesfully in the Yonsei Cardiovascular Center, Sevrance Hospital, Yonsei University College of Medicine. This system consisted with Server and Clients which is communicated through LAN(Ethernet). The system also use the Host computer(IBM 9221 170) as a data bank and communicates to the Server with emulation card(3270 emulator, Interlink Inc., Korea) . After introducing this system, it enables patients to receive drugs witllin 20 minutes after prescription of 300-400 patients per day and it seemed to be effective system not to reduce waiting time for the patients but also to remove charge-troubling(due to His-entry of prescription) . This system also seems to be effective in terms of office automatism for hospital management. However users, usually physitions, required more friendly and easy system to operate and we thought that the most important one to successfully introduce order communication computer system in the hospital is user interface.

• 수산해양기술연구
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• 제51권4호
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• pp.520-526
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• 2015

A tragic disaster happened by capsizing O-Ryong 501 trawler at Western Bering Sea in 1st, Dec. 2014. The disaster was caused by the severe weather and the long deferred escape from the storm in fully developed high sea. Lots of sea water from poop deck rushed into the fish ponder with fishes all together after hauling net and then remove the fishes from codend. The vessel became to incline to the one side caused by the weight and the free surface effect of flood sea waters and fishes at initial stage. In spite of crews all effort to discharge the waters, but the work was not achieved successfully. For the worse thing, the order of abandon ship was issued too late. After all, the ship capsized and sank, then almost crews became to the victims of the casualty including captain. In this paper, author carried out restrictively the calculation of dynamic factors influenced on the disaster including the weather condition and effects of the flood sea waters, and found out that the most important causes of the disaster were the decrease of stabilities, GM was decreased from 0.9m to 0.08 m, and the high waves which led to the vessel disaster.

• 대한치과기공학회지
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• 제22권1호
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• pp.113-128
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• 2000

The purpose of this study was to serve as a basis for the development of dental technology and for creating a condition that dental technicians could work with pride and right values, by examining what problems there were in their health care, what they thought about them, and how the problems could be solved, The findings of this study were as below: 1. The most serious and harmful element in dental technology workshop was a dust(57.5%) and a noise(33.3%). 2. Approximately 99.0% of the dental technicians investigated made a complain of air pollution caused by noise. Their opinion on a possible measure to remove noise air pollution was that the noise-generating machine should be replaced(64.1%) or that it should be isolated(28.8%). 3. 76.0% complained air pollution cause by dust deteriorates their working efficiency. As a way to eliminate it, they suggested a dust chamber(35.3%) or an air cleaner(27.5%) should be installde. 4. About 80% made a complain of gas air pollution. The most common related symptom was a headache(56.9%). They thought that gas-generating machine should be isolated(39.9%) or that an air purifier should be prepared(33.3%). 5. The largest impact of heat and light on their body was weakening their eyesight(56.9%). 47.1% got burn once though four times, and 34.3% did five times or more. The way to prevent them was to install an automatic casting machine(66.0%) or use protective glasses(28.1%). 6. Approximately 47.7% were considering a change of occupation, and the most common reason was heavy work(23.5%), followed by poor prospect(21.6%) and working environment(19.0%) in the order named. 7. 88.9% responded they were likely to have an occupational disease. Their idea about the proper frequency of regular health examination was once a year(53.6%), or once per every six months(41.8%). 8. The field they were most interested in was health care(39.2%), followed by academic research activities(31.4%). This fact indicated it's most urgently required to improve their working environment.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1992년도 추계학술대회
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• pp.97-99
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• 1992

After development of order communication system for out-patients using PC and LAN in May 1992, this system had been tested for 2 months. The system also use Host computer(IBM 9221-170) as a data bank and communicats wi th emulation card(3270 emulator. Interlink Inc., Korea). Since September 1992, this system(named YOUSEI-PC) has been running successfully in the Yonsei Cardiovascular Center of the Severance Hospital, Yonsei University College of Medicine. After introducing this system, it enables patients to receive drugs wi thin 30 minutes after prescription and revealed effective system not to reduce waiting time for the patients but also to remove charge-troubling(due to mis-entry of prescription). This system also seems to be effective in terms of office automatism for hospital management. However users, usually physitions, required more friendly and easy system to operate and we thought that the most important one to successfully introduce order communication computer system in the hospital is user interface.

• Child Health Nursing Research
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• 제5권2호
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• pp.198-210
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• 1999

The goal of respiratory management in high risk infants is to maintain proper oxygenation by supporting respiration, therefore to minimize the secondary complications and to promote the maximum growth and development. While on artificial ventilator to achieve this goal, the infants require endotracheal suctioning(ETS) to remove lung secretions. However, the negative effects of ETS in neoates have been documented and include hypoxia, bradycardia, mucosal damage, increased intracranial pressure, and death result. The purpose of the study was to investigate how ETS is currently performed in NICU, which would be beneficial to develop the standardized ETS protocol and to apply it to these population. A national-wide survey on clinical protocol of ETS was performed to 149 neonatal nurses with the average of 3 years and 6 months experience in neonatal nursing, 34.2% of whom was bachelor in nursing. The results showed that about 89% of the nurses initiate En primarily based on the need of the subjects. The aseptic regulation on ETS was used in 83.9% of the subjects. There was no regulation on the length of catheter in 32.9% and on ID/OD ratio in 17.4%. Many nurses administered hyperoygenation/hyperinflation/hyperventilation based on personal knowhow, rather than scientific rationals (77.2%, 40.9%, 75.2%, retrospectively). About 41% of the nurse regulate subjectively the suction power, while 73.8% of them rotate the sub ject's head during suctioning and the half of the nurses was favorable in adapting the closed-suctioning protocol. With the findings of the study, the current clinical application of E% in neonates appears to be based on adult care practices, or personal preference, rather than scientific validation of the safety and effectiveness of the procedure. This study support the needs for developing and applying the standardized ETS protocolin conjunction with the consideration given to the physiologic characteristics of the neonates in respiratory distress.

• 디지털융복합연구
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• 제17권3호
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• pp.205-213
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• 2019

건설현장의 굴토작업과 흙막이 가시설은 서로 밀접한 관계를 가지고 있다. 협소한 공간에서 가장 효율적으로 지하구조물을 축조하고 굴토작업시 외측 배면의 토사 이완을 방지하고 지하수위를 유지하기 위한 방안으로 안전성이 확보된 흙막이 가시설 설치는 반드시 필요하다. 본 연구는 기존 지하층 굴토공사에서 흙의 유실을 방지하기 위해 설치하는 가설흙막이를 종래에는 가설벽체를 형성하고 어스앵커, 래커, 스트러트 등을 이용하여 내부 지보를 하고 굴토공사를 시행하던 방식에서, RSB공법은 기존 재래식공법의 문제점을 개선하여, 내부 지보재를 제거하고 2열 엄지말뚝과 브레이싱을 이용하여 자립으로 토압에 저항하도록 하여 지반굴착을 진행하는 공법이다. 본 연구에서는 RSB공법 현장시범적용과 계측결과를 통하여 굴착방법에 따른 흙막이 가시설의 공법 적용성, 평가결과 발생변위가 모두 계측 허용치 만족하고. 기존 재래식공법에 비해 시공성과 경제성이 향상되었다.

• 대한금속재료학회지
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• 제48권4호
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• pp.335-341
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• 2010

High-quality single-walled carbon nanotubes (SWCNTs) were synthesized by catalytic decomposition of $C_2H_2$ using Fe-Mo/MgO catalyst at $800^{\circ}C$. The as-synthesized SWCNTs typically occurred in the form of a bundle with a diameter of 10~20 nm together with amorphous carbon and catalytic impurities, which were removed by a two-step purification process consisting of oxidation and an acid treatment. The oxidation step, using an $O_2$-Ar mixture at $380^{\circ}C$ for 5 hr in a vertical-type furnace and a $HNO_3$ treatment at $100^{\circ}C$ for one hour, was utilized to remove the amorphous carbon particles. Subsequently, metallic catalysts were removed in HCl at room temperature for 5 hr under magnetic stirring. The SWCNT suspension was prepared by dispersing the purified SWCNTs in an aqueous sodium dodecyl benzene sulfonate solution with horn-type sonication. This was then air-sprayed on glass to fabricate CNT field emitters. The samples had a turn-on field value of 4 V/${\mu}m$ and a current density of 0.67 mA/$cm^2$ at 9 V/${\mu}m$. Increasing the HCl treatment time improved the field emission properties.

• Journal of Information Science Theory and Practice
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• 제10권3호
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• pp.40-56
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• 2022

This paper aims to implement a topic modeling technique for extracting the topics of online discussions among library professionals in India. Topic modeling is the established text mining technique popularly used for modeling text data from Twitter, Facebook, Yelp, and other social media platforms. The present study modeled the online discussions of Library and Information Science (LIS) professionals posted on Lis Links. The text data of these posts was extracted using a program written in R using the package "rvest." The data was pre-processed to remove blank posts, posts having text in non-English fonts, punctuation, URLs, emails, etc. Topic modeling with the Latent Dirichlet Allocation algorithm was applied to the pre-processed corpus to identify each topic associated with the posts. The frequency analysis of the occurrence of words in the text corpus was calculated. The results found that the most frequent words included: library, information, university, librarian, book, professional, science, research, paper, question, answer, and management. This shows that the LIS professionals actively discussed exams, research, and library operations on the forum of Lis Links. The study categorized the online discussions on Lis Links into ten topics, i.e. "LIS Recruitment," "LIS Issues," "Other Discussion," "LIS Education," "LIS Research," "LIS Exams," "General Information related to Library," "LIS Admission," "Library and Professional Activities," and "Information Communication Technology (ICT)." It was found that the majority of the posts belonged to "LIS Exam," followed by "Other Discussions" and "General Information related to the Library."