• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.9C
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• pp.887-898
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• 2005

In this paper, we introduce a probabilistic model based on Bayesian networks BNs) for recognizing human fatigue. First of all, we measured face feature information such as eyelid movement, gaze, head movement, and facial expression by IR illumination. But, an individual face feature information does not provide enough information to determine human fatigue. Therefore in this paper, a Bayesian network model was constructed to fuse as many as possible fatigue cause parameters and face feature information for probabilistic inferring human fatigue. The MSBNX simulation result ending a 0.95 BN fatigue index threshold. As a result of the experiment, when comparisons are inferred BN fatigue index and the TOVA response time, there is a mutual correlation and from this information we can conclude that this method is very effective at recognizing a human fatigue.

• The Journal of Internal Korean Medicine
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• v.22 no.3
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• pp.299-307
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• 2001

Objectives: Fatigue is a common symptom experienced by many people who visit Oriental medical clinics or hospital. However, there has been little study about the fatigue in the Oriental medical academic world. For this reason, we attempted to investigate the present status of fatigue of outpatients, and its relation with Health Practice Index(HPI). Methods: The subjects were 63 outpatients who visited the Tonification Clinic in Kyunghee Oriental Medical Center between January 1, 2001 and July 31, 2001. Their chief complaint was fatigue and they did not have any physical or mental problem. They were given a questionnaire which included questions reflecting general characteristics, fatigue degree and health habits. We measured degree of fatigue by Chalder scale et al. Health habits were investigated about 5 articles out of 'Breslow 7 Health habits'. Results: Among the subjects, 48 people(76.2%) were considered as 'fatigue patients' by the Chalder scale. Of this 48 fatigue patients, 27 people(56.3%) had manifested fatigue for more than 6 months. The average of scale II for all the patients was 14.05, which indicates moderate degree of fatigue. They complained fatigue, drowsiness and general weakness, dryness and discomfort of the eyes, headache, shoulder pain and neck stiffness, dizziness, heat in the upper part of the body, and poor concentration. There were no differences in degree of fatigue according to Health habits including exercise or not, smoking or not, the frequency of drinking, hours of sleeping, and body mass index. Conclusions: Many people complain fatigue symptom. Therefore doctors should have more interest in fatigue and care. This study can provide standards of prognosis of fatigue patients. Also prospective studies are needed to find relationship between health habits and fatigue degree.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.32 no.3
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• pp.124-129
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• 2021

Background and Objectives This study compares Vocal Fatigue Index (VFI) scores according to the presence or absence of external laryngeal tension in hyperfunctional voice disorder. And through this, it is to confirm the usefulness of VFI to hypertension of extrinsic laryngeal muscles. Materials and Method The subjects were 61 female diagnosed with hyperfunctional voice disorder (hypertension group 41, non-hypertension group 20). The author palpated extrinsic laryngeal muscles for evaluation of hypertension and classified them as the presence or absence. The voice measurements were jitter, shimmer, Korean-Voice Handicap Index-10 (K-VHI-10), and Korean-Vocal Fatigue Index (K-VFI). The voice compared were according to the diagnosis and presence of hypertension only for patients with hyperfunctional voice disorder. Results As a result of comparing the voice measurement according to the presence or absence of hypertension, there was no significant difference in the acoustic variables, K-VHI-10 and K-VFI-Total, K-VFI-Fatigue. Whereas, K-VFI-Physical (p=0.006) and K-VFI-Rest (p=0.022) were significantly higher in the hypertension group. Conclusion These results indicate that the hypertension group has more physical discomfort and less voice recovery than the group without hypertension. It means that K-VFI can measure the physical discomfort and limitations of voice recovery due to hypertension of the external laryngeal muscle. The VFI can be used as one of the methods to evaluate the hypertension of the external laryngeal muscle in Hyperfunctional voice disorder.

• Physical Therapy Korea
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• v.11 no.2
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• pp.17-25
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• 2004

The purpose of this study was to assess the effect of applied insole types to lower extremities muscle fatigue during treadmill exercise. The control group and each different insole type group consisted of ten healthy male subjects. In the control group and each different insole type (soft type; 10 shore, semi-rigid type; 33 shore, rigid type; 50 shore) treadmill exercise was performed in twenty-five minutes. The electromyography (EMG) signals of four muscle (tibialis anterior, gastrocnemius medialis, rectus femoris, biceps femoris) were recording at sampling rate of 1024 Hz during treadmill exercise. The localized muscle fatigue (LMF) can be investigated using power spectral analysis. When did data analysis that excepted initial five minutes. The raw EMG signals was processed using the fast Fourier Transformation (FFT) and the median power frequency value was determined in initial ten second period and in last ten second period. Fatigue index was calculated and collected data were statistically analyzed by SPSS version 10.0 two-way using analysis of variance (ANOVA) with repeated measures ($4{\times}4$) was used to determine the main effect and interaction. Post hoc was performed with least significant difference. A level of significance was .05. Muscles fatigue index were significantly decreased in insole types (p<.05) and not significantly different in muscle (p>.05). Post hoc analysis shows that fatigue index in soft insole type, semi-rigid insole type and rigid insole type were lower than that control group (p=.028, p=.146, p=.095). There were no interaction between insole type and muscles (p>.05). The finding of this study can be used as a fundamental data when insole is applied and insole can be used to decreased of a fatigue during the dynamic exercise.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.4
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• pp.27-33
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• 1997

Spot welding has been used in the sheet metal jointing processes because of its high productivity and convenience. In this study, effects of welding conditions on the fatigue life and prediction methods of fatigue life of spot welded joint have been studded . Fatigue life was estimated by stress index parameter considering multiaxial stresses. Fatigue tests were conducted with the tensile-shear specimens using SPCC. Fatigue life of spot welded joint was influenced by welding currents and was predicted exactly with taking into account StageIII.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.04a
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• pp.137-142
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• 1997

Spot welding has been used in the sheet metal joining processes because of its high productivity and convenience. In this study effects of welding conditions on the fatigue life and predicting methods of fatigue life of spot welded joint have been studied. Fatigue life was estimated by stress index parameter considering multiaxial stresses. Fatigue tests were conducted with the tensile-shear specimens using SPCC. Fatigue life of spot welded joint was influenced by welding currents and was predicted exactly with taking into account Stage III.

• The Journal of Korean Physical Therapy
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• v.19 no.3
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• pp.11-17
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• 2007

Purpose: The purpose of this study were to analyze fatigue patterns of the rectus femoris muscle by isometric contraction. Methods: Twenty healthy subjects(10 male, 10 female) participated in this study. Maximal voluntary isometric contraction(MVIC) was measured by the dynamometer. Muscle activity was recorded from the rectus femoris muscle. During the experiment, the subject was seated in the chair. The measured items, median frequency(MDF) and root mean square (RMS), were collected from the surface EMG. All data were analyzed using repeated measures ANOVA. Results: There was significant difference of MVIC between male and female. Endurance time was significant difference by the level of MVIC but no significant in the main effect(sex) and interaction effect. The MDF and fatigue index were significant differences in the interaction effect. The RMS was not significant difference in both of main and interaction effect. The muscle fatigue patterns of female was greater than male after 60% MVIC. Conclusion: This study showed that sex differences of muscle fatigue were started from 60% MVIC.

• Steel and Composite Structures
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• v.20 no.4
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• pp.913-930
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• 2016

It is common practice to use Reduced Web Beam Sections (RWBS) in steel moment resisting frames. Perforation of beam web in these members may cause stress and strain concentration around the opening area and facilitate ductile fracture under cyclic loading. This paper presents a numerical study on the cyclic fracture of these structural components. The considered connections are configured as T-shaped assemblies with beams of elongated circular perforations. The failure of specimens under Ultra Low Cycle Fatigue (ULCF) condition is simulated using Cyclic Void Growth Model (CVGM) which is a micromechanics based fracture model. In each model, CVGM fracture index is calculated based on the stress and strain time histories and then models with different opening configurations are compared based on the calculated fracture index. In addition to the global models, sub-models with refined mesh are used to evaluate fracture index around the beam to column weldment. Modeling techniques are validated using data from previous experiments. Results show that as the perforation size increases, opening corners experience greater fracture index. This is while as the opening size increases the maximum observed fracture index at the connection welds decreases. However, the initiation of fracture at connection welds occurs at lower drift angles compared to opening corners. Finally, a probabilistic framework is applied to CVGM in order to account for the uncertainties existing in the prediction of ductile fracture and results are discussed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.9 s.252
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• pp.1142-1147
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• 2006

A practical method for reducing the number of spot welds in automotive structures considering fatigue crack initiation life is suggested. At first, an influence index for the durability and the fatigue life of a spot weld itself is defined and then taken as the main effect of the DOE analysis. Spot welds that can be removed without serious reduction of durability through numerical experiments are selected by the results of DOE. The proposed method was applied to the shock tower and LCA(lower control arm) structure of a vehicle, which are important components in durability-related point of view.

• Proceedings of the KWS Conference
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• 1997.10a
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• pp.77-80
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• 1997

Spot welding has been used in the sheet metal joining processes because of its high productivity and convenience. In this study, predicting methods of fatigue life of spot welded joint have been studied fatigue life of conch-peel spot welded joint was influenced by tail effect. Fatigue life was estimated by stress index parameter considering multiaxial stresses and tail effect. Fatigue tests were conducted with the coach-peel specimens using SPCC.