• Smart Structures and Systems
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• v.5 no.4
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• pp.329-344
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• 2009

Ultrasonic chaotic excitations combined with sensor prediction algorithms have shown the ability to identify incipient damage (loss of preload) in a bolted joint. In this study we examine a physical experiment on a single-bolt aluminum lap joint as well as a three-dimensional physics-based simulation designed to model the behavior of guided ultrasonic waves through a similarly configured joint. A multiple bolt frame structure is also experimentally examined. In the physical experiment each signal is imparted to the structure through a macro-fiber composite (MFC) patch on one side of the lap joint and sensed using an equivalent MFC patch on the opposite side of the joint. The model applies the waveform via direct nodal displacement and 'senses' the resulting displacement using an average of the nodal strain over an area equivalent to the MFC patch. A novel statistical classification feature is developed from information theory concepts of cross-prediction and interdependence. This damage detection algorithm is used to evaluate multiple damage levels and locations.

• Journal of the Korea Safety Management & Science
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• v.12 no.4
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• pp.81-86
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• 2010

Despite the importance of cycling postures during cycling performances, there has been a very little research investigating cycling postures and pedaling rate for particularly concerning domestic cyclists. The aim of this study was to analyze correlations and effects between cycling postures and pedaling rate in track cycling. Twelve male racing cyclists (six racing and university cyclists) participated in this research. For this study, seven infrared cameras (Qualisys ProReflex MCU-240s) were used for collecting data and these were processed via QTM (Qualisys Tracker Manager) software. It appeared that pedaling rate had correlations with regard to a shoulder angle (R=-.601) and displacement between shoulder joints(R= -.637), but a knee (R=-.601) and ankle angle (R=.667). Moreover, two multiple regression equations of pedaling rate for cycling postures were significant and R2 of the first order equation y (pedaling rate) = 0.039x (knee angle) - 1.068 was less than the second order equation y = 0.006x2 - 1.287x + 69.674. In conclusion, cycling postures affected the pedaling rate. Further study should be researched on postures in relation to air resistance in a wind tunnel.

• Journal of Korean Academy of Nursing
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• v.17 no.3
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• pp.218-226
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• 1987

This descriptive-correlational study was undertaken in order to examine if there were relationships between family support, compliance and life satisfaction in chronic arthritis patients. The sampling method was a non-probability, purposive sampling technique. The participants of this study were 92 volunteer adults. 1) who have been diagnosed as having chronic arthritis and 2) who were at the medical out patient clinic of one university hospital in Seoul between April 27th to May 12th 1987. The instruments used for this study were the Family Support Scale developed by Kang Hyun Sook, a Compilance Scale developed by the researcher and the Life-Satisfaction Index-Z developed by Wood et.al. Analysis of data was done using t-test, ANOVA, Pearson Correlation Coefficient and Stepwise Multiple Regression Analysis. The results of study were as follows; Hypothesis I; “The higher the family support, the higher the compliance” was accepted. (r＝.2604, p＜.01) Hypothesis II; “The higher the compliance, the higher the life satisfaction,” was rejected. (r＝.1663, p＞0.5) Hypothesis III; “The higher the family support, the higher the life satisfaction” was accepted. (r＝.3914, p＜.01) In addition, by using Stepwise Multiple Regression Analysis it was determined that the main influencing factors on the life satisfaction were family support, the number of inflammatory joints, compliance and pain level. These 4 main variables made it possible to explain 30.8% of the variance in life satisfaction. In conclusion, this study revealed that family support is an important factor that can improve compliance and life satisfaction in chronic arthritis patients.

• Imaging Science in Dentistry
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• v.48 no.2
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• pp.147-152
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• 2018

Synovial chondromatosis is a rare metaplastic disease affecting the joints, including the temporomandibular joint (TMJ). Since its symptoms are similar to those of temporomandibular disorders, a careful differential diagnosis is essential. A 50-year-old male patient was referred with the chief complaint of pain and radiopaque masses around the left TMJ on panoramic radiography. Clinically, pre-auricular swelling and resting pain was found, without limitation of mouth opening. On cone-beam computed tomographic images, multiple calcified nodules adjacent to the TMJ and bone proliferation with sclerosis at the articular fossa and eminence were found. T2-weighted magnetic resonance images showed multiple signal-void nodules with high signal effusion in the superior joint space and thickened cortical bone at the articular fossa and eminence. The calcified nodules were removed by surgical excision, but the hypertrophic articular fossa and eminence remained. A histopathological examination confirmed the diagnosis. The patient was followed up few months later without recurrence.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.6
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• pp.3182-3198
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• 2019

Vision-based Human Pose Estimation has been considered as one of challenging research subjects due to problems including confounding background clutter, diversity of human appearances and illumination changes in scenes. To tackle these problems, we propose to use a new multi-stage convolution machine for estimating human pose. To provide better heatmap prediction of body joints, the proposed machine repeatedly produces multiple predictions according to stages with receptive field large enough for learning the long-range spatial relationship. And stages are composed of various modules according to their strategic purposes. Pyramid stacking module and dilation module are used to handle problem of human pose at multiple scales. Their multi-scale information from different receptive fields are fused with concatenation, which can catch more contextual information from different features. And spatial and channel information of a given input are converted to gating factors by squeezing the feature maps to a single numeric value based on its importance in order to give each of the network channels different weights. Compared with other ConvNet-based architectures, we demonstrated that our proposed architecture achieved higher accuracy on experiments using standard benchmarks of LSP and MPII pose datasets.

• Smart Structures and Systems
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• v.30 no.4
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• pp.397-410
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• 2022

It is essential to monitor the working conditions of bolt-connected joints, which are widely used in various kinds of steel structures. The looseness of bolts may directly affect the stability and safety of the entire structure. In this study, a guided wave-based method for bolt looseness detection and localization is presented for a joint structure with multiple bolts. SH waves generated and received by a small number (two pairs) of magnetostrictive transducers were used. The bolt looseness index was proposed based on the changes in the reconstructed responses excited by the time reversal signals of the measured unit impulse responses. The damage locations and local damage severities were estimated using the damage indices from several wave propagation paths. The back propagation neural network (BPNN) technique was employed to identify the local damages. Numerical and experimental studies were conducted on a lap joint with eight bolts. The results show that the total damage severity can be successfully detected under the effect of external force and measurement noise. The local damage severity can be estimated reasonably for the experimental data using the BPNN constructed by the training patterns generated from the finite element simulations.

• Journal of Korean Foot and Ankle Society
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• v.9 no.2
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• pp.209-212
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• 2005

Osteochondral lesion usually occurs in the elbow, knee and ankle joints. Many articles about osteochondral lesion of the talus in the ankle joint have been reported. We experienced a rare case of partially detached osteochondral lesion of the tibial plafond treated with excision and multiple drilling.

• Journal of Korean Neurosurgical Society
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• v.58 no.1
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• pp.89-92
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• 2015

Rheumatoid arthritis (RA) is a chronic inflammatory disease involving multiple joints. The cervical spine is often affected, and cases involving atlantoaxial joint can lead to instability. Anterior atlantoaxial subluxation in RA patients can lead to posterior neck pain or occipital headache because of compression of the C2 ganglion or nerve. Here, we report the successful treatment of a RA patient with occipital radiating headache using pulsed radiofrequency therapy at the C2 dorsal root ganglion.

• Structural Engineering and Mechanics
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• v.40 no.3
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• pp.297-313
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• 2011

As bridge conditions in the United States continue to deteriorate, rapid bridge replacement procedures are needed. Decked precast prestressed concrete (DPPC) girders are used for rapid bridge construction because the bridge deck is precast with the girders eliminating the need for a cast-in-place slab. One of the concerns with using DPPC girders as a bridge construction option is the durability of the longitudinal joints between girders. The objectives of this paper were to propose a method to use a spring element modeling procedure for representing welded steel connector assemblies between adjacent girders in DPPC girder bridges, perform a preliminary study of bridge performance under multiple loading scenarios and bridge configurations, and discuss model flexibility for accommodating future field data for model verification. The spring elements have potential to represent the contribution of joint grout materials by altering the spring stiffness.

• Imaging Science in Dentistry
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• v.40 no.1
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• pp.45-52
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• 2010

Synovial chondromatosis is an uncommon disorder characterized by metaplastic formation of multiple cartilaginous and osteocartilaginous nodules within connective tissue of the synovial membrane of joints. Osteochondroma is a benign lesion of osseous and cartilagenous origin. It is frequently found in the general skeleton, but is rare in the mandibular condyle. We experienced 2 patients with abnormal appearance of temporomandibular joint. Histologic diagnoses were not obtained, because surgery was unwarranted in view of the lack of symptoms and the benign differential diagnosis. We describes 2 cases that show the characteristics of both disease simultaneously.