• Journal of the Society of Naval Architects of Korea
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• v.57 no.5
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• pp.254-261
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• 2020

The structural safety of hydraulic winch drum and the gears are estimated by the Finite Element Analysis (FEA) and the winch operation experiment. The mesh convergence test is performed and the applied force is the pressure on the drum converted from the rope tension in working condition. The stress of the drum calculated from the strain values of the winch operation experiment shows the agreement with that from the FEA. Most stress values are under the yield strength except for the small hole made for the wire rope fixation. The life of bearings in the drum is calculated using the life prediction formula with the reaction forces from the operation load. One of the two ball bearings shows the short life for impact condition, yet the real prototype winch system shows more life than the numerical value.

• Journal of Drive and Control
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• v.19 no.3
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• pp.32-38
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• 2022

The in-wheel drive gearbox for military special vehicles converts the high-speed & low-torque output generated by the electric servomotor, into low-speed & high-torque mechanical power. As the vehicle is remotely maneuvered in mountainous terrain, wet fields, rough terrain, etc., the gearbox must generate a maximum input speed exceeding 5,000 rpm, a maximum torque of 245 Nm, and MTBF of 9,600 km. The purpose of this study was to analyze the failure mode of the gearbox, to ensure the durability of the in-wheel drive gearbox. Also, the field load test data of the vehicle was analyzed, the acceleration durability test standards were established, the acceleration durability test was conducted, and the durability test results were analyzed as well.

• Journal of Drive and Control
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• v.21 no.1
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• pp.16-21
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• 2024

The yaw gearbox is a key device in a wind power generator that improves power generation efficiency by rotating hundreds of tons (400 to 600 tons) of nacelle so that the blade reaches 90 degrees in the wind direction. Recently, installation sites have been advancing from land to sea as they have become super-large at (8-12) MW to increase the economic feasibility of wind power generators and utilize excellent wind resources, and the target life of large wind power generators is 25 to 30 years. The yaw gearbox of 6 to 12 sets is installed in a very complex place inside the nacelle on the tower with parallels, and it is important to secure the reliability of the yaw gearbox because if a failure occurs after installation, it costs tens to hundreds of times the price of a new product to restore. In this study, equivalent loads were calculated by analyzing failure mode and field data, accelerated life test conditions were established, and a test device was constructed to perform the accelerated life tests and performance tests to ensure the reliability of the gearbox.

• Korean Journal of Occupational Health Nursing
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• v.7 no.1
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• pp.65-82
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• 1998

This study was carried out in order to confirm the reliability and validity of the commitment inventory developed by Meyer and Allen, and to investigate commitment level of health manager, to compare two different professionals of health manager such as industrial health nurse and industrial hygienist to find out some characteristics that have effect on commitment. This survey was done by self-administered questionnaire to 227 respondents as the trainees of Industrial Safety Training Center, KISCO from June to December 1996. Authors classified commitment into two categories ; professional commitment and organizational commitment, and these two types of commitments have three different aspects ; affective, continuance, and normative commitment based on Meyer's inventory. The results were as follows; 1. Items of whole scales of the both type of commitments have three factors that represent three aspects of commitment ; affective, continuance, and normative commitment. This means that each type of commitment was reliable to use as measurement tool of three different aspects of commitment. Classification of items by factor analysis was more consistent in professional commitment than organizational commitment. Among 16 items of organizational commitment, four items were classified into different aspects of commitment with similar factor loading. 2. Commitment level of industrial health nurse was higher than that of industrial hygienist in affective, continuance professional commitment controlled by other characteristics. These differences can be due to other characteristics of specific task and background of health managers that were not used in this study. 3. The level of affective professional commitment was statistically different in age, sex, educational level, and that of organizational commitment was statistically different in only two variables such as age, and job tenure. The level of continuance professional and organizational commitments were different in sex group, but past history of employment have effect on continuance organizational commitment. The level of normative organizational commitment was affected by only age. As the above results, the tools of measurement of commitment developed by Meyer and Allen can be useful to measure the level of commitment of health manager. Three aspects of two types of commitments were influenced by different characteristics of health manager. Authors suggested future study on the affecting variables to the commitment such as background, task of health manager and organizational characteristics.

• KIISE Transactions on Computing Practices
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• v.23 no.9
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• pp.517-534
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• 2017

This paper proposes an Internet of Things (IoT) middleware called Middleware for Cooperative Interaction of Things (MinT). MinT supports a fully distributed IoT environment in which IoT devices directly connect to peripheral devices, easily constructing a local or global network and sharing their data in an energy efficient manner. MinT provides a sensor abstract layer, a system layer and an interaction layer. These layers enable integrated sensing device operations, efficient resource management, and interconnection between peripheral IoT devices. In addition, MinT provides a high-level API, allowing easy development of IoT devices by developers. We aim to enhance the energy efficiency and performance of IoT devices through the performance improvements offered by MinT resource management and request processing. The experimental results show that the average request rate increased by 25% compared to existing middlewares, average response times decreased by 90% when resource management was used, and power consumption decreased by up to 68%. Finally, the proposed platform can reduce the latency and power consumption of IoT devices.

• Journal of Acupuncture Research
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• v.33 no.1
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• pp.103-116
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• 2016

Objectives : This study was performed to assess the effectiveness of conservative Korean traditional medical treatment on lumbar intervertebral disc herniation in 12 adolescents. Methods : Data were collected from adolescent patients diagnosed with lumbar intervertebral herniation by MRI, hospitalized at Jaseng Korean Medicine Hospital from January 1, 2014 to December 31, 2015. A total of 12 patients were included in the study. Patients were treated by acupuncture, pharmacopuncture, electroacupuncture, herbal medicine, chuna manual therapy, physical therapy during hospitalization period. To measure treatment outcomes, a verbal numerical rating scale (VNRS), Oswestry disability index (ODI), range of motion (ROM), Straight leg raising test (SLR), and EQ-5D were used. Results : The average age of the participants was $16.05{\pm}1.62$. The average of duration of symptom was $19.25{\pm}26.83(weeks)$ and the average length of hospitalization was $23.8{\pm}16.4(days)$. 2 patients (17 %) suffered from only lumbar pain, while 10 patients (83 %) suffered from lumbar and leg pain. No participant suffered from only leg pain. 8 patients (67 %) were diagnosed with disc herniation in one segment, and 4 patients (33 %) were diagnosed with disc herniation in multiple segments. A total of 17 disc segments (28 %) were herniated. The most herniated lumbar level was L4-5. 3 segments were diagnosed with bulging (17 %), 6 with protrusion (35 %), and 8 with extrusion (47 %). Extrusion was the most frequent herniated type. After treatment, the average VNRS of lumbar pain significantly decreased from $5.58{\pm}1.62$ to $2.91{\pm}1.56$ (p<0.001) and the average VNRS of leg pain significantly decreased from $5.16{\pm}2.51$ to $3.08{\pm}1.8$ (p<0.001). ODI significantly decreased from $48.87{\pm}18.72$ to $28.57{\pm}15.05$ (p<0.05), and EQ-5D significantly increased $0.58{\pm}0.31$ to $0.80{\pm}0.12$ (p<0.05). Range of flexion significantly improved from $61.25{\pm}32.62$ to $68.33{\pm}26.22$ (p<0.05). Conclusion : Conservative Korean Traditional Medical Treatment may be effective in the treatment of lumbar intervertebral disc herniation in adolescence. However, more case reports and clinical research are needed.

• Tuberculosis and Respiratory Diseases
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• v.46 no.5
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• pp.729-734
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• 1999

Broncho-esophageal fistula(BEF) is an uncommon clinical entity which can cause severe suppurative lung disease. Acquired fistulas between the esophagus and tracheobronchial tree are relatively uncommon. They are caused by many diseases including malignancy and chronic inflammation such as tuberculosis and have favorable outcome with proper treatment To our knowledge, there has been no description of patients with BEF due to the bronchiectasis. We report a case of broncho-esophageal fistula in association with bronchiectasis in a 35-year-old male patient with hemoptysis. Bronchoscopy revealed mild bleeding from the superior segment of the right lower lobe without specific endobronchial lesion. Barium esophagogram could not confirm the fistula. The diagnosis of a broncho-esophageal fistula was established by an esophagogastroscopy using fistulogram and subsequent bronchoscopy, in which the communication between the bronchial tree and the esophagus was demonstrated by instilling dye selectively through the fistulous opening using esophagogastroscopy and visualizing the fistula and the bronchial tree. The patient was treated with resection of the right lower lobe, extirpation of the diverticulum and surgical closure of the bronchial defect and fistula, but he suffered from pneumonia thereafter and eventually expired due to sepsis and multiple organ failure.

• Journal of the Korean Arthroscopy Society
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• v.7 no.1
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• pp.52-57
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• 2003

Purpose : To evaluate the morphologic measurement and microvasculature of the normal human meniscus in Korean and to compare the difference of microvasculature according to the age and anatomical location. Materials and methods : Menisci of 21 cadavers divided into 3 groups according to the age. Each meniscus was divided into 10 parts of which the width and area of microvasculature were measured. Results : The average width of the medial and lateral menisci were $10.49{\pm}02.92mm$ and $10.55{\pm}2.05mm$, respectively. The average area of the microvasculature measured $20.29{\pm}8.44\%$ in the medial meniscus and $18.99{\pm}7.03\%$ in the lateral meniscus. The microvasculature of the medial meniscus was most abundant in the anterior horn and least abundant in the posterior horn (p<0.05). The lateral meniscus showed the most vessels in the posterior horn (p<0.05). The microvasculature of popliteal hiatus was not avascular but hypovascular. The area of microvasculature decreased with increasing age in all parts of the medial meniscus and body and posterior horn of the lateral meniscus (p<0.05). Conclusion : Differences in the anatomical distribution of the vessels were noted of both the medial and lateral menisci. The area of microvasculature generally decreased proportionally with increasing age in both medial and lateral meniscus.

• Journal of Acupuncture Research
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• v.33 no.4
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• pp.65-72
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• 2016

Objectives : While neck pain is highly prevalent in Korea, studies examining its Korean medical treatment are currently lacking. The aim of this study was to assess current Korean medical treatment practice patterns for neck pain. Methods : A preliminary questionnaire was developed to investigate current practice patterns of neck pain and cervical intervertebral disc displacement (IDD) treatment, and underwent further revision through external review. The final questionnaire was distributed as a web-based survey to 18,289 potential respondents by email. Results : The response rate was 3.34 %. Most participants replied that they received multiple Korean medicine interventions for neck pain treatment consisting of such methods as acupuncture, wet cupping, interferential current therapy and electroacupuncture. A total of 378 respondents acknowledged that diagnostic testing was needed for neck pain treatment. The most commonly used Korean Standard Classification of Diseases (KCD) principal diagnosis code for neck pain was M542, and for cervical IDD was M501. Conclusion : This survey study helps determine current practice patterns of neck pain, and recognizes the need for use of diagnostic devices in neck pain treatment. These results are further anticipated to provide basic data for clinical practice guidelines (CPGs) and future studies using Korean National Health Insurance and Health Insurance Review & Assessment Service data.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.10
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• pp.928-935
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• 2015

This paper presents low temperature structural tests of a UAV wing which has room temperature-curing adhesive bond. The wing structure is made of carbon fiber reinforced composites, and the skins are bonded to the inner structures (such as ribs and spars) using room temperature-curing adhesive bond. Also, to verify damage tolerance design of the wing structure, barely visible impact damages are intentionally created in the critical areas. The attachment fittings of the wing are fixed in a specially designed chamber which can simulate the low temperature environments of the operating altitudes. The test load is applied by hydraulic actuators which are placed outside the chamber. The structural tests consist of strain survey tests and a durability test for 1-life fatigue load spectrum. During the tests, strains of major parts are measured by strain gauges and FBG sensors. The change of the initial impact damages is also monitored using piezoelectric sensors. The 1-life damage tolerance of the composite structure is verified by the structural tests under the simulated environments.