• Journal of Electrical Engineering and Technology
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• v.1 no.1
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• pp.101-105
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• 2006

In this paper, a disk-type ultrasonic motor using a combination of radial and bending vibration modes is newly designed and fabricated. The characteristics of the test motor are also measured. By means of traveling elastic wave induced at the surface of circumference of the elastic disk, a steel bar in contact with the surface of circumference of the elastic disk bonded onto the piezoelectric ceramic disks is driven in both directions by changing the sine and cosine voltage inputs. The stator of the motor is composed of two sheets of piezoelectric ceramic disks to bond onto both surfaces of an elastic disk, respectively. As a result, the diameter of the elastic body is increased and the resonant frequency is decreased. The resonant frequency of the stator is about 92 kHz, which is composed with piezoelectric ceramic disks of 28 mm in diameter and 2 mm in thickness, and an elastic body of 32 mm in diameter and 2 mm in thickness. A driving voltage of 20 VPP Produces 200 rpm with a torque of 1Nm and an efficiency of about 10%.

• The Journal of the Convergence on Culture Technology
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• v.4 no.4
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• pp.429-438
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• 2018

Recently, there has been a tendency for accidents occurring in manufacturing to lead to serious accidents and serious industrial accidents and to extend to community disasters. In accordance with the Third Plan (2015-2019) of the National Security Management Plan, the Safety Administration announces and promotes improvement measures to minimize industrial accidents and disasters. In the case of industrial accidents from KOSHA 2015 to 2017, the accident rate of the metal-related manufacturing industry is 1.57%, which is more than three times higher than the average 0.50% of all industries. As a result of investigating the causes of disasters, 72% of workers were found to be caused by unsafe behaviors. In addition, insecure behaviors are closely related to safety consciousness, and a survey on safety consciousness was conducted for workers in this field. Safety consciousness improvement has the affirmative effect on accident prevention and it is a factor to reduce accidents.

• The Plant Pathology Journal
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• v.39 no.4
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• pp.397-408
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• 2023

Fire blight disease, caused by Erwinia amylovora, is a devastating affliction in apple cultivation worldwide. Chemical pesticides have exhibited limited effectiveness in controlling the disease, and biological control options for treating fruit trees are limited. Therefore, a relatively large-scale survey is necessary to develop microbial agents for apple trees. Here we collected healthy apple trees from across the country to identify common and core bacterial taxa. We analyzed the endophytic bacterial communities in leaves and twigs and discovered that the twig bacterial communities were more conserved than those in the leaves, regardless of the origin of the sample. This finding indicates that specific endophytic taxa are consistently present in healthy apple trees and may be involved in vital functions such as disease prevention and growth. Furthermore, we compared the community metabolite pathway expression rates of these endophyte communities with those of E. amylovora infected apple trees and discovered that the endophyte communities in healthy apple trees not only had similar community structures but also similar metabolite pathway expression rates. Additionally, Pseudomonas and Methylobacterium-Methylorobrum were the dominant taxa in all healthy apple trees. Our findings provide valuable insights into the potential roles of endophytes in healthy apple trees and inform the development of strategies for enhancing apple growth and resilience. Moreover, the similarity in cluster structure and pathway analysis between healthy orchards was mutually reinforcing, demonstrating the power of microbiome analysis as a tool for identifying factors that contribute to plant health.

• Journal of Convergence for Information Technology
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• v.10 no.9
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• pp.164-172
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• 2020

The purpose of this study was to analyze the effect of male university student perceptions of dating violence on dating violence abuse behavior and damage behavior. The subjects of the study were 233 students from six departments at U University located in Chungbuk. As a research instrument, Haeun Yoon's(2013) instrument was used to recognize dating violence, and CTS2 was used as a instrument for harassment and damaging behavior of dating violence. For data analysis, correlation analysis between dating violence perception and damage behavior was performed, and regression analysis was performed to determine the effect of dating violence perception on dating violence harassment and damage behavior. First, it was shown that there was a significant negative correlation between the harassment behavior or damage behavior and perception of dating violence in male university students. Second, it was found that the recognition of dating violence had a significant negative effect on the harassment behavior and damage behavior of dating violence. The results of the research could be used as basic data to develop a dating violence prevention program.

• The Journal of the Korea Contents Association
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• v.9 no.6
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• pp.247-255
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• 2009

This study aims to provide basic data for establishing the safety and health plan by investigating the exposure conditions in the facilities registering business about handling radiations and radioactive isotopes in Korea. dose levels(working space, worker location) of the workers in 153 facilities were measured using surveymeter, and individual exposure concentration[(shallow dose(SD), depth dose(DD)] in 27 facilities using thermal luminescence dosimeter(TLD). In accordance with the measurement results by business type[fire fighting prevention business(FFPB, n=10), financial insurance business(FIB, n=3) and other facilities(n=140)] using surveymeter, those three business type groups showed difference (p<0.000). Dose levels of worker location for FFPB and FIB were significantly higher than 10.0 ${\mu}Sv$/hr, the allowable standard for radiations and radioactive isotopes, and they were higher 109.3 times(p<0.000) and 187.5 times(p<0.000) than those in other facilities. The concentration of TLD[FFPB(n=10), other facility (n=17)] in DD of FFPB was significantly higher than that in other facility(p=0.05). In accordance with the analysis result on relationship between surveymeter and TLD, the dose on working space and worker location(r=0.406, p<0.05), worker location dose and SD(r=0.453, p<0.05), worker location dose and DD(r=0.553, p<0.01), and SD and DD(r=0.927, p<0.001) had all related each other. It is urgently required to change FFPB and FIB from the facilities requiring registration for handling radiations and radioactive isotopes to the facilities that shall get permission for handling radiations and radioactive isotopes by reestablishing the legal administration area, for safety and health of radiation occupants.

• Journal of Korean Society of Archives and Records Management
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• v.5 no.2
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• pp.27-48
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• 2005

This study investigates the current preservation and management of four records and documentary heritage in Korea that is in the UNESCO's Memory of the World Register. The study analyzes their problems and corresponding solutions in digitizing those world records heritages. This study also reviews additional four documentary books in Korea that are in the wish list to add to UNESCO's Memory of the World Register. This study is organized as the following: Chapter 2 examines the value and meanings of world records and documentary heritage in Korea. The registry requirements and procedures of UNESCO's Memory of the World Register are examined. The currently registered records of Korea include Hunmin-Chongum, the Annals of the Choson Dynasty, the Diaries of the Royal Secretariat (Seungjeongwon Ilgi), and Buljo- Jikji-Simche-Yojeol (vol. II). These records heritage's worth and significance are carefully analyzed. For example, Hunmin-Chongum("訓民正音") is consisted of unique and systematic letters. Letters were delicately explained with examples in its original manual at the time of letter's creation, which is an unparalleled case in the world documentary history. The Annals of the Choson Dynasty("朝鮮王朝實錄") are the most comprehensive historic documents that contain the longest period of time in history. Their truthfulness and reliability in describing history give credits to the annals. The Royal Secretariat Diary (called Seungjeongwon-Ilgi("承政院日記")) is the most voluminous primary resources in history, superior to the Annals of Choson Dynasty and Twenty Five Histories in China. Jikji("直指") is the oldest existing book published by movable metal print sets in the world. It evidences the beginning of metal printing in the world printing history and is worthy of being as world heritage. The review of the four registered records confirms that they are valuable world documentary heritage that transfers culture of mankind to next generations and should be preserved carefully and safely without deterioration or loss. Chapter 3 investigates the current status of preservation and management of three repositories that store the four registered records in Korea. The repositories include Kyujanggak Archives in Seoul National University, Pusan Records and Information Center of National Records and Archives Service, and Gansong Art Museum. The quality of their preservation and management are excellent in all of three institutions by the following aspects: 1) detailed security measures are close to perfection 2) archiving practices are very careful by using a special stack room in steady temperature and humidity and depositing it in stack or archival box made of paulownia tree and 3) fire prevention, lighting, and fumigation are thoroughly prepared. Chapter 4 summarizes the status quo of digitization projects of records heritage in Korea. The most important issue related to digitization and database construction on Korean records heritage is likely to set up the standardization of digitization processes and facilities. It is urgently necessary to develop comprehensive standard systems for digitization. Two institutions are closely interested in these tasks: 1) the National Records and Archives Service experienced in developing government records management systems; and 2) the Cultural Heritage Administration interested in digitization of Korean old documents. In collaboration of these two institutions, a new standard system will be designed for digitizing records heritage on Korean Studies. Chapter 5 deals with additional Korean records heritage in the wish list for UNESCO's Memory of the World Register, including: 1) Wooden Printing Blocks(經板) of Koryo-Taejangkyong(高麗大藏經) in Haein Temple(海印寺); 2) Dongui-Bogam("東醫寶鑑") 3) Samguk-Yusa("三國遺事") and 4) Mugujeonggwangdaedaranigyeong. Their world value and importance are examined as followings. Wooden Printing Blocks of Koryo-Taejangkyong in Haein Temple is the worldly oldest wooden printing block of cannon of Buddhism that still exist and was created over 750 years ago. It needs a special conservation treatment to disinfect germs residing in surface and inside of wooden plates. Otherwise, it may be damaged seriously. For its effective conservation and preservation, we hope that UNESCO and Government will schedule special care and budget and join the list of Memory of the Word Register. Dongui-Bogam is the most comprehensive and well-written medical book in the Korean history, summarizing all medical books in Korea and China from the Ancient Times through the early 17th century and concentrating on Korean herb medicine and prescriptions. It is proved as the best clinical guidebook in the 17th century for doctors and practitioners to easily use. The book was also published in China and Japan in the 18th century and greatly influenced the development of practical clinic and medical research in Asia at that time. This is why Dongui Bogam is in the wish list to register to the Memory of the World. Samguk-Yusa is evaluated as one of the most comprehensive history books and treasure sources in Korea, which illustrates foundations of Korean people and covers histories and cultures of ancient Korean peninsula and nearby countries. The book contains the oldest fixed form verse, called Hyang-Ka(鄕歌), and became the origin of Korean literature. In particular, the section of Gi-ee(紀異篇) describes the historical processes of dynasty transition from the first dynasty Gochosun(古朝鮮) to Goguryeo(高句麗) and illustrates the identity of Korean people from its historical origin. This book is worthy of adding to the Memory of the World Register. Mugujeonggwangdaedaranigyeong is the oldest book printed by wooden type plates, and it is estimated to print in between 706 and 751. It contains several reasons and evidence to be worthy of adding to the list of the Memory of the World. It is the greatest documentary heritage that represents the first wooden printing book that still exists in the world as well as illustrates the history of wooden printing in Korea.