• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.1
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• pp.31-39
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• 2013

A Quad Tilt Wing UAV is a new concept hybrid UAV having the advantages of both fixed-wing and rotary-wing aircraft. This paper presents longitudinal flight dynamic characteristics of a Quad Tilt Wing UAV. The designed Quad Tilt Wing UAV is a configuration of a tandem wing type aircraft with an actuating motor and propeller mounted at each wing. Momentum theory is used to calculate the thrust, and nonlinear modeling is performed considering lift and drag generated by slip stream effect of propellers. Also, Force and moment variation at each tilting angle is considered. Static trim on longitudinal axis is analyzed via numerical simulation. Componentwise force contribution was analyzed at each trim mode. Dynamic characteristics were evaluated through eigenvalue analysis for a linear model at each flight mode. It is verified that longitudinal dynamic characteristics are changing from unstable to stable state by continuous transition of dominant poles.

• Korean Journal of Applied Biomechanics
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• v.24 no.3
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• pp.239-248
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• 2014

The purpose of this study was to quantify kinematic and kinetic characteristics of Yin-yang Bo gait according to their motor expertise, one of the Seokmun Ilwol martial art gait patterns. Yin-yang Bo gait pattern shows initial forefoot contact instead of heel contact, and increased time of stance phase time, internal-external rotation of ankle-knee-hip joints and pelvic. It aims to produce and store the more energy through continuous homeostasis of center of gravity (COG) and performance of stretch-shortening cycle. Some of these characteristics also were similar to the gait modification strategies for reducing knee adduction moment such as toe-out progression, medial thrust, internal rotation of hip joint. To identify the characteristics, four factors of expert Yin-yang Bo gait performance group were compared to that of none expert group; 1) angles of COG displacement and rotation 2) distal joint pre-rotation in internal-external rotation of ankle-knee-hip joints and pelvic, 3) invariability pelvic potential and pelvic segment total energy 4) knee abduction moment. Six healthy(three male) subjects participated in the experiment to perform Yin-yang gait pattern. Three-dimensional and force plate data were collected. Kinematic and kinetic data were compared between two groups using t-tests. Results showed that 1) the peak point of COG internal rotation angle was reduced in expert group, 2) kneeexternal and hip joint -internal and pelvic rotation angle peak frames were more near points in expert group.

• Korean Journal of Community Nutrition
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• v.9 no.4
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• pp.519-527
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• 2004

This study was designed firstly to measure the job satisfaction (JS) levels of personnel engaged in contract food-service management company (CFMC), secondly to compare the job satisfaction levels by personal and company-related characteristics, and thirdly to identify the effects of JS facets on overall job satisfaction. Of 1135 respondents, there were 712 employees in the headquarters and 423 in the branch office. From an analysis on job satisfaction, overall job satisfaction level was 3.22 out of a maximum 5 and the co-worker (3.71) facet of JS was the highest job satisfaction followed by supervision (3.32), work itself (3.26), working condition (3.15), promotion (2.95) and payroll (2.74). In comparison of job satisfaction by personal characteristics, the personnel who were male (p < .01), had associate degrees (p < .01) or long-term careers in foodservice field (p < .05), or were regular employees (p < .01) perceived significantly higher than others for overall JS. In comparison of the job satisfaction by company-related characteristics, overall JS was significant by company scale (p < .01) and by work place (p < .05), but it was not significant by operating group. Finally, on the regression analysis for the effects of JS facets on overall JS, adjusted R2 was 0.534 (p < .001) and all six JS facets, especially payroll, had a positive effect on overall JS significantly (p < .001). Considering that the goal of enterprise on profit-making through customer satisfaction (CS) and the role of personnel on CS at moment of thrust (MOT), the findings confirmed the necessity for continuous internal marketing and human relation management focusing on the lower level of JS facets.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.72-76
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• 2010

To research and develop a high performance injector for LRE, it needs not only cold flow test, but also investigations of combustion performance, optimization of cyclogram and thermo-fluid dynamical characteristics of combustion flow field through hot-fire test. In this study, hot-fire test of LOX-CH4 coaxial swirl injector has been carried out using lab-scale hot fire test stand which can supply and control cryogenic propellant. Ignition and continuous combustion for LOX-$GCH_4$ propellant of 0.19 kg/s total mass flowrate and 2.80 O/F Ratio was achieved through cyclogram optimization. The mean combustion chamber pressure and thrust were measured as approximately 1.43 MPa and 38.7 kgf respectively.

• Journal of Urban Science
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• v.11 no.2
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• pp.19-24
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• 2022

Conventional RC beams for crossing small and medium-sized rivers do not have a cross-sectional area, so the floating debris is accumulated and disasters such as damage to bridges occur. To improve this, the PSC method was invented. However, this also had problems such as transverse curvature, increase in dead weight due to cross-sectional shape, and negative moment generated during serialization, so it was necessary to develop a new type of girder. Therefore, it was intended to propose a LIT(Leton Interaction Thrust) girder bridge that is safer and has better performance than the conventional PSC girder with improved section efficiency. Unlike existing girder bridges, the LIT girder has the feature that the change in the strands of the entire girder occurs only in the vertical direction when the first tension is applied because the tendon arrangement is symmetrical by applying the raised portion. In addition, slab continuation generates a secondary moment that is advantageous to the continuous point, effectively controlling the negative moment and preventing the corrosion of the tendon. The dimensions of the cross section were determined, and the arrangement of the strands was designed to conduct structural analysis and detailed analysis. As a result of the structural analysis, the stress of the girder showed results within the allowable compressive stress, and the deflection showed the result within the allowable deflection. showed results. In addition, a detailed analysis was performed to examine the stress distribution around the girder body and the anchorage area and the stress distribution of the embossed portion, and as a result, the stress of the girder body due to the tension force showed a stable level.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.29 no.1
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• pp.81-93
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• 2023

Purpose: The current case study focuses on identifying the effects of manual therapy and home self-therapeutic exercise including on mouth opening and pain relief in patients with continuous neck pain with myofascial temporomandibular disorders (TMDs) accompanied by headache induced by masticatory myalgia Subjects: The study participant was a 27-year-old woman who was treated a year ago for pain related to TMDs accompanied by a headache. Methods: Manual therapy of the cervical spine with upper cervical spine posterior-to-anterior mobilization (C1~C2), upper cervical spine flexion mobilization (C0~C2), upper cervical spine lateral flexion mobilization (C0~C1), upper cervical spine thrust manual therapy (C1~C2) and manual therapy of the temporomandibular joint and muscles with transverse medial accessory temporomandibular joint mobilization, manual therapies for the temporal, the masseter, and medial pterygoid muscles were performed twice a week for about 30 minutes for 4 weeks. This protocol included 3 sessions in total. The home self-therapeutic exercise was to be performed two to three times a day. Results: The values more improved MMO increased to 41.4 mm, left masseter muscle PPT to 2.9 kgf/cm², right masseter muscle PPT to 3.1 kgf/cm², KHIT-6 to 46 points, neck pain intensity (by NRS) to 2 points, headache frequency to per weeks, cervical kyphotic angle to -8.06%, and GCPS to grade 1 (low-intensity pain without pain-related disorder). Conclusion: Manual therapy and home self-therapeutic exercise can be helpful for mouth opening and pain relief in patients with myofascial TMDs accompanied by secondary headaches induced by masticatory myalgia.

• The Journal of the Petrological Society of Korea
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• v.7 no.1
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• pp.37-52
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• 1998

The granites in the Jeomchon area can be divided into hornblende biotite granite (Hbgr), deformed biotite granite (Dbgr), deformed pinkish biotite granite(Dpbgr), biotite granite (Btgr), and granite porphyry(Gp). These granites show metaluminous, 1-type and calc-alkaine characteristics from their whole-rock chemistry. Hbgr and Dbgr belong to ilmenite-series granitoids, but Gp to magnetite-series. Dpbgr and Btgr show the intermediate nature between ilmenite- and magnetite-series. Tectonic discriminations indicate that Hbgr and Dbgr were formed in active continental margin environment, whereas Dpbgr, Btgr, and Gp in post-orogenic and/or anorogenic rift-related environment. From the Harker diagrams major oxide contents of Hbgr and Dbgr show a continuous variation with $SiO_2$, indicating that they are genetically correlated with each other. On the other hand, any correlation of major oxides variation cannot be recognized among Dpbgr, Btgr and Gp. It seems like that Hbgr and Dbgr were derived from a same parent granitic magma, judging from their occurrence of outcrop, mineral composition as well as whole-rock chemistry. Variation trends of major oxide contents between Hbgr and Baegnok granodiorite are very similar and continuous. If the two granites were derived from a cogenetic magma, there exists a possibility that the granitic bodies had been separated by Btgr and Gp of Cretaceous age. Three stages of the granitic intrusions are understood in the Jeomchon area. After the intrusion of Hbgr and Dbgr during middle to late Paleozoic time, Dpbgr emplaced into the area next, and finally Btgr and Gp intruded during Cretaceous time. Tectonic movement accompanying shear and/or thrust deformation seems likely to have occurred bewteen the intrusions of Dpbgr and Btgr.