• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.65-67
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• 2012

The butt-joint system is widely used as the method of roof composite waterproofing system. However, there is stilll no objective research about proper distance, and proper structure associated with the performance in butt-joint system. In this research, we find proper distance and proper structure in butt-joint system through tensile strength test at joint, and comparative analyze with practical construction material of composite waterproofing sheet.

• Journal of Oral Medicine and Pain
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• v.44 no.2
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• pp.59-64
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• 2019

Purpose: The aim of this study was to analyse and evaluate the morphology of the articular eminence of temporomandibular joint in young Korean adults using cone-beam computed tomography (CBCT). Methods: One hundred seventy-one subjects (59 males, 112 females) in the 20s were examined using CBCT. Width and height of articular eminence, top-roof line angle, best-fit line angle, joint space were measured. For the group comparisons, independent t-test was used with the level of significance established at $p{\leq}0.05$. Results: In asymptomatic young Korean adults, average eminence width was $9.49{\pm}1.62mm$ in males and $9.33{\pm}1.36mm$ in females. Average eminence height was $7.23{\pm}1.81mm$ in males and $6.82{\pm}1.31mm$ in females. Average eminence inclination of measured by top-roof line angle was $37.09^{\circ}{\pm}7.74^{\circ}$ in males and $36.12^{\circ}{\pm}5.65^{\circ}$ in females. Average eminence inclination measured by best-fit line angle was $50.79^{\circ}{\pm}11.49^{\circ}$ in males and $48.43^{\circ}{\pm}9.05^{\circ}$ in females. Average joint space was $3.03{\pm}0.67mm$ in males and $2.63{\pm}0.68mm$ in females. Conclusions: Increasing age did not affect the morphology of the articular eminence in asymptomatic young Korean adults. Males had slightly larger eminence width, height, top-roof line angle, best-fit line angle and joint space, but no statistical significance (p>0.05) was observed only in the joint space (p=0.001). There was no side-to-side difference in morphology (p>0.05).

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.3
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• pp.61-72
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• 1996

In this paper, the driver seat comfort of eight automobiles was studied. The joint angles and anthropometric data of eleven subjects sitting on the seating buck were investigated using the instrument devices such as scale, goniometer, vernier calipers, protractor, Martin set. The joint angles of the most comfort posture were found by experiment and compared with previous studies. The anthropometric data of Korean(1992 year surveys) and American(1970∼1974 year) were applied to evaluate the driver seat layout of Korean automobile. The joint angles of the most comfort posture for eleven subjects were obtained with experimental results. The joint angles were agreed with reference angles. The driver seat layout was not suited to seat length and acceleratorseatpan forward distance in 5 percentiles female, pedal separation and seatpan-roof height in 95 percentiles male. Korean automobiles were not suited to seatpan length and steering wheelseatpan clearance, floor-roof height for American 95 percentiles male. The driver anthropometric dimensions were more suitable to middle size than small size automobiles.

• Steel and Composite Structures
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• v.1 no.1
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• pp.17-32
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• 2001

The Rosette-joining system is a completely new press-joining method for cold-formed steel structures. One Rosette-joint has a shear capacity equal to that of approximately four screws or rivets. The Rosette thin-walled steel truss system presents a new fully integrated prefabricated alternative to light-weight roof truss structures. The trusses are built up on special industrial production lines from modified top hat sections used as top and bottom chords and channel sections used as webs which are joined together with the Rosette press-joining technique to form a completed structure easy to transport and install. A single web section is used when sufficient but can be strengthened by double-nesting two separate sections or by using two lateral profiles where greater compressive axial forces are met. An individual joint in the truss can be strengthened by introducing a hollow bolt into the joint hole. The bolt gives the connection capacity a boost of approximately 20%. A series of laboratory tests have been carried out in order to verify the Rosette truss system in practice. In addition to compression tests on individual sections of different lengths, tests have also been done on small structural assemblies and on actual full-scale trusses of a span of 10 metres. Design calculations have been performed on selected roof truss geometries based on the test results, FE-analysis and on the Eurocode 3 and U.S.(AISI) design codes.

• Journal of the Korea Concrete Institute
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• v.28 no.2
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• pp.235-244
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• 2016

This study was conducted to verify seismic performance of special moment frame's joints at roof-level with high-strength concrete and SD600 bars. K-RC-H was designed according to the seismic code and K-HPFRC-H had 150% of the original hoop spacing and 1.0% steel fiber volume fraction compared with K-RC-H. Both specimens had remarkable seismic performance without noticeable decrease in moment, but with very good energy dissipation before rebar failure. The U-bars in the joint sufficiently constrained rebar's action that pushed the cover upward. SD600 bars with $1.25l_{dt}$ had minimum slip in the joint. It was considered that the steel fiber contributed to improvement of the bending moment and joint shear distortion, and the result showed that it would be possible to increase the hoop spacing to 150% of the regular spacing.

• Structural Engineering and Mechanics
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• v.32 no.2
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• pp.321-335
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• 2009

When a roof frame is subjected to the airblast loading, the conventional way to analyze the damage of the frame or design the frame is to use single degree of freedom (SDOF) model. Although a roof frame consists of beams and girders, a typical SDOF analysis can be conducted only separately for each component. Thus, the rigid body motion of beams by deflections of supporting girders can not be easily considered. Neglecting the beam-girder interaction in the SDOF analysis may cause serious inaccuracies in the response values in both Pressure-Impulse curve (P-I) and Charge Weight-Standoff Diagrams (CWSD). In this paper, an inelastic two degrees of freedom (TDOF) model is developed, based on force equilibrium equations, to consider beam-girder interaction, and to assess if the modified SDOF analysis can be a reasonable design approach.

• Journal of Oral Medicine and Pain
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• v.44 no.4
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• pp.154-159
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• 2019

Purpose: The aim of this study was to assess the change in thickness of the roof of the glenoid fossa (RGF) in patients undergoing orthognathic surgery using cone-beam computed tomography (CBCT) images. Methods: This retrospective study measured the thickness of the RGF in 19 patients (10 males, 9 females) who underwent orthognathic surgery at Chosun University Dental Hospital. The thickness of the RGF was measured perpendicularly between the 'glenoid fossa line' and 'middle cranial fossa line' on parasagittal and paracoronal reconstructions. Results: The mean RGF thickness increased from 0.83±0.44 mm to 0.86±0.46 mm after surgery. The average change in thickness of the RGF was 0.17±0.18 mm. The thickness of the RGF in the temporomandibular joint (TMJ) showed no significant difference by sex, and the change in thickness of the TMJ did not vary by surgical method. Conclusions: We found that the thickness of the RGF increased after orthognathic surgery, as revealed by CBCT. Further studies including larger numbers of subjects and long-term follow-up are needed to confirm the results of this study.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.728-735
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• 2022

Roofers get exposed to increased risk of knee musculoskeletal disorders (MSDs) at different phases of a sloped shingle installation task. As different phases are associated with different risk levels, this study explored the application of machine learning for automated classification of seven phases in a shingle installation task using knee kinematics and roof slope information. An optical motion capture system was used to collect knee kinematics data from nine subjects who mimicked shingle installation on a slope-adjustable wooden platform. Four features were used in building a phase classification model. They were three knee joint rotation angles (i.e., flexion, abduction-adduction, and internal-external rotation) of the subjects, and the roof slope at which they operated. Three ensemble machine learning algorithms (i.e., random forests, decision trees, and k-nearest neighbors) were used for training and prediction. The simulations indicate that the k-nearest neighbor classifier provided the best performance, with an overall accuracy of 92.62%, demonstrating the considerable potential of machine learning methods in detecting shingle installation phases from workers knee joint rotation and roof slope information. This knowledge, with further investigation, may facilitate knee MSD risk identification among roofers and intervention development.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.214-221
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• 2001

The Great Hall of Incheon International Airport Transportation Center has irregular curved roof structure. The structure consists of 13 main steel trusses. (the longest span of 162m, 480ton) The total weight of the truss is 6,300ton and the whole truss is made of 9,600 pieces which has the joint connected to maximum 13 different parts at one point and Roof Truss is supported by 12 Fabric Foundation. Considering the economical efficiency and the schedule, the Sliding Construction Method was used other than conventional erection method. The roof truss structure was divided into two blocks, 3,550ton and 2,700ton, each block was pre-erected on the Giant Sleigh off the site and was pulled 181m by using Tandem Pulling Jack and Strand to be set in place.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.179-183
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• 2005

In apply roof waterproof system using of synthetic high polymer sheet for rooftop measure physical performance (tension$\cdot$tearing ability, temperature relativity, heating stretch performance, junction performance, wind resistance test) by various test environment condition waterproof test of structure and performance of construction work aspect, present suitable form of construction work under these environment. Also, wish to improve durability of concrete structure as that examine in priority about adhesion method and joint junction method with waterproof out surface, and present new direction about roof system application of waterproofing method for rooftop.