• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.12
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• pp.3943-3959
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• 2022

People are constantly exposed to stress and anxiety environment, which could contribute to a variety of psychological and physical health problems. Therefore, it is particularly important to identify psychological stress in time and to find a feasible and universal method of stress reduction. This research investigated the influence of different music, such as relaxation music and natural rhythm music, on stress relief based on Electroencephalogram signals. Mental arithmetic test was implemented to create a stressful environment. 23 participants performed the mental arithmetic test with and without music respectively, while their Electroencephalogram signal was recorded. The effect of music on stress relief was verified through stress test questionnaires, including Trait Anxiety Inventory (STAI-6) and Self-Stress Assessment. There was a significant change in the stress test questionnaire values with and without music according to paired t-test (p<0.01). Furthermore, a model based on Transformer for stress level classification from Electroencephalogram signal was proposed. Experimental results showed that the method of listening to relaxation music and natural rhythm music achieved the effect of reducing psychological stress and the proposed model yielded a promising accuracy in classifying the Electroencephalogram signal of mental stress.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.11
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• pp.2442-2449
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• 2002

This paper provides an reference stress based J estimation equation fur cylinders with finite internal axial surface cracks under internal pressure. In part 1, the J estimation equation based on deformation plasticity using Ramberg-Osgood (R-0) materials is proposed. In this paper, the developed CE/EPRI -type solutions ale then re-formulated based on the reference stress concept. Such a re-formulation provides a simpler equation for J. estimation are then further extended to combined internal pressure and bending. The proposed reference stress based J estimation equation is compared with elastic-plastic 3-D FE results using actual stress-strain data for a Type 304 stainless steel. Good agreement between the FE results and the proposed reference stress based J estimations provides confidence in the use of the proposed method to elastic -plastic fracture mechanics of pressurised piping.

• Structural Engineering and Mechanics
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• v.62 no.6
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• pp.781-788
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• 2017

In this paper, a stress wave model is established to describe the three states (separate, contact and impact) of clearance joints. Based on this stress wave model, the propagation characteristics of stress wave generated in clearance joints is revealed. First, the stress wave model of clearance joints is established based on the viscoelastic theory. Then, the reflection and transmission characteristics of stress wave with different boundaries are studied, and the propagation of stress wave in viscoelastic rods is described by the characteristics method. Finally, the stress wave propagation in clearance joints with three states is analyzed to validate the proposed model and method. The results show the clearance sizes, initial axial speeds and material parameters have important influences on the stress wave propagation, and the new stress waves will generate when the clearance joint in contact and impact states, and there exist some high stress region near contact area of clearance joints when the incident waves are superposed with reflection waves, which may speed up the damage of joints.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.2 s.140
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• pp.129-135
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• 2005

At present, fatigue design of welded structures is primarily based on a nominal stress or hot spot stress approach with a series of classified weld S-N curves. Although well accepted by major industries, the nominal stress based fatigue design approach is cumbersome in terms of securing a series of S-N curves corresponding to each class of joint types and loading modes. The hot spot stress based fatigue design has a difficulty of finding a proper stress through the global model, the midium size model, and the detail model of ship structure. Also, it is difficult to link proper displacements within three different mesh size models. Recently, the structural stress is proposed as a mesh-size insensitive structural stress definition that gives a stress state at weld toe with relatively large mesh size. However, this method requires an experimental validation in obtaining the fatigue strength of weldments. Therefore, in this study, a series of experiment is performed for various sizes of weldments.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.11 s.242
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• pp.1488-1493
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• 2005

In this study, fatigue tests to obtain S-N curves and FE analyses to obtain structural stress concentration factors were conducted for the two types of cruciform fillet welded joints, that is, load-carrying and non load-carrying types. Then we changed the obtained S-N curve of load carrying joint to that based on hot spot stress. As a result, the S-N curve of load carrying joint based on hot-spot stress was almost exactly coincided with that of non load-carrying joint based on nominal stress. So we have conducted that the fatigue strength of a welded joint with different geometry from the non stress distribution along the expected crack path.

• Journal of the Korea Society of Computer and Information
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• v.22 no.11
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• pp.73-79
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• 2017

The purpose of this study was to identify differences in stress, interpersonal relations, learning perceptions and self-efficacy of nursing students participating in team based learning simulation practices. The study group consisted of 24 students in the third grade who attended nursing college. Data were collected using questionnaires. The collected data were analyzed by SPSS 22 version's descriptive statistics, t-test, and paired t-test. The results showed that stress and learning perceptions were significantly different according to gender, leave of absence in pre and post - test. After the practice of team - based simulation, the stress of nursing college students decreased and interpersonal relations and self - efficacy were improved. The results of this study showed that nursing students' gender and absence of school should be considered in the team - based simulation. Further research on team based simulation practice involving interpersonal relationships is needed.

• Composites Research
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• v.28 no.1
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• pp.6-14
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• 2015

Polymerization shrinkage stress analysis of dimethacrylate-based composite (Clearfil AP-X, Kuraray) and silorane-based composite (Filtek P90, 3M ESPE) used for dental composite restorations was performed using strain-gage measurement and FEM analysis. A theoretical equation based on Young's modulus and polymerization shrinkage of the composite resin was proposed to predict the polymerization shrinkage stress. Experimental results showed that the maximum shrinkage stress of Clearfil AP-X was about 2.8 times higher than Filtek P90. FEM analysis agreed with such experimental stress behaviours and showed that the maximum Von-Mises stress appeared near the margin of the filled resin adhered with PMMA ring. The stress concentration at the interface on the specimen surface was higher than that in the interior. The maximum error of shrinkage stress by the theoretical equation was reasonable within 5% in comparison to FEM results under plane stress.

• 한국초등상담교육학회:학술대회논문집
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• 2004.01a
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• pp.137-168
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• 2004

The purpose of this study is to find the effect of group counseling program based on reality therapy that is developed by researcher and to investigate whether the program can decrease the academic stress of elementary school students. For this study, firstly a framework for academic stress decrease programs is established and a program is developed in accordance with the framework. Secondly, in order to verify the effect of the program, both quantitative and qualitative methods were applied to 6th grade students through a academic stress test. Experimental group and control group is composed of 18 students, each. During a two month-experimental period, group counseling program based on reality therapy was implemented to the experimental group for 10 sessions but not to the control group. The program included nicknaming, recreation activities to promote friendliness among participants and other various activities to decrease the academic stress. The results of the quantitative and statistical research are as follows: First, group counseling program based on reality therapy is effective to decrease of elementary school students' academic stress. Second, sub factor(such as perceptions of academic stress cause, symptoms of academic stress)of academic stress is significantly decreased in experimental group. But no significant difference is found in control group. Third, for some sub factor(career, friend-relationship, house-environment, behavior-symptom), an independent-sample test and a paired-sample test showed different results: the paired-sample test showed no significant differences in experimental group while the independent-sample test showed significant decrease of academic stress. The results of the qualitative research based on student commentaries on the program is as follows: First, experimental group students report that the program based on reality therapy was effective to decrease of academic stress. Second, experimental group students' commentaries shows that students could remember the WDEP, 'act' factor and acquire the solution of academic stress. Third, for a group counseling, students reported the interest about positive feedback, searching on themselves, growth of human-relationship. This means that the program developed on this study is suitable for group counseling program. In conclusion, this study proves that group counseling program based on reality therapy is effective to decrease of elementary school students' academic stress by increasing individual internal-control. Therefore, it is necessary that we should develop and apply similar program to elementary school students in other to decrease students' academic stress. school students in other to decrease students' academic stress.

• The Journal of Information Systems
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• v.20 no.2
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• pp.155-176
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• 2011

The use of mobile office systems has been expanded due to the smartphones' rapid diffusion in Korea, and it has brought a new work environment that is different from traditional working patterns. In this study, the unique attributes of mobile office systems, such as ubiquity, usefulness, complexity, and insecurity, are examined along with the impact of these attributes on work overload and job stress. Based on transaction-based model of job stress, organizational support was applied as a stress inhibitor and also the moderator between work overload and job stress. The findings of this study show that ubiquity increases usefulness of mobile office systems; complexity increases both work overload and job stress; and insecurity increases job stress. Surprisingly, usefulness increases job stress, which means employees who perceive the efficiency of mobile office systems higher may feel more job stress. Organizational support for mobile office systems significantly shows the moderating effect, but no direct mitigating effect on job stress. The theoretical and practical implications in order to mitigate the side effects of mobile office systems based on the research findings are thoroughly discussed.

• Korean Journal of Oriental Medicine
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• v.3 no.1
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• pp.119-151
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• 1997

Conclusions for the relationship between a conceptional model of stress theory and its examination based on the Oriental medicine; 1. It was considered that a general conception of stress is included into the meaning of Ki in the Oriental medicine. 2. The response-based model to stress could be comparable to a conception of Ki-pathogens interchange In the Onental medicine. 3. The stimulus-based model may be explained as a modern conception of immoderation feeling related with an internal etiological factor, specially injury of seven emotions, among three groups of etiological factors for disease. 4. The feedback conception based on the interaction model could explain the principal of reversible emotion therapy in the nine Ki. 5. In the Oriental medicine, a study to clarify a emotional etiologic factor and its pathophysiologlcal mechanism has been continued for long time before establishment of stress theory.