• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.5
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• pp.381-387
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• 2017

Fiber-reinforced composites not only have a direction of thermal expansion coefficient, but also inevitably suffer thermal stress effects due to the difference between the manufacturing process temperature and the actual use temperature. The damage caused by thermal stress is more prominent in the case of thick composite laminates, which are increasingly applied in the aerospace industry, and have a great influence on the mechanical function and fracture strength of the laminates. In this study, the dimensional reduction and thermal stress recovery theory of composite beam structure having high slenderness ratio is introduced and show the efficiency and accuracy of the thermal stress comparison results between the 3-D finite element model and the dimension reduction beam model. Efficient recovery analysis study will be introduced by reconstructing the thermal stress of the composite beam section applied to the thermal environment by constructing the dimensional reduction modeling and recovery relations.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.7 no.2
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• pp.107-114
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• 2011

Dental extraction is potentially stress-inducing in many disabled patient. The body's response to dental stress involves the cardiovascular system(an increase in cardiovascular workload), the respiratory organ and the endocrine system(change in metabolism). To minimize the stress, the stress reduction method was established. The obtained contents were as follows: (1) Recognize the patient's degree of medical risk, (2) Complete medical consultation before dental therapy, (3) Schedule the patient's appointment in the morning, (4) Monitor and record preoperative and postoperative vital signs, (5) Use psychosedation during therapy, (6) Use adequate pain control during therapy, (7) Short length of appointment : do not exceed the patient's limits of tolerance, (8) Follow up with postoperative pain/anxiety control, (9) Telephone the risk patient later on the same day that treatment was given. Though the stress reduction method above was applied to the dental extraction in disabled patients with the advanced infected teeth, the complications(syncope, shock, bleeding & infection, etc.) may be occurred. For prevention of complications associated with the extraction, the authors treated the advanced infected teeth with endodontic drainage and incision & drainage before extraction. The final extraction and wound closure were then done after about 3 weeks.

• The Journal of Advanced Prosthodontics
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• v.7 no.3
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• pp.240-248
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• 2015

PURPOSE. To explore whether there is matching relation between the length and the tilting angle of terminal implants in the All-on-Four protocol by studying the effects of different implant configurations on stress distributions of implant, bone, and framework. MATERIALS AND METHODS. Four implants were employed to support a full-arch fixed prosthesis and five three-dimensional finite element models were established with CT images, based on the length (S and L) and distal tilt angle ($0^{\circ}$, $30^{\circ}$ and $45^{\circ}$) of terminal implants for an edentulous mandible, which named: Tilt0-S, Tilt30-S, Tilt30-L, Tilt45-S and Tilt45-L. An oblique 240 N was loaded at second molar. The von Mises Stresses were analyzed. The implants were consecutively named #1 to #4 from the loading point. RESULTS. 1) Tilt0-S had the greatest stress on the implants, with the other groups exhibiting variable reductions; the four implants of Tilt45-L demonstrated the greatest reduction in stress. 2) Tilt0-S had the greatest stress at bone around #1 implant neck, and Tilt45-L exhibited the least stress, which was a 36.3% reduction compared to Tilt0-S. 3) The greatest stress in the framework was found on the cantilevers distal to #1 implant. Tilt45-S exhibited the least stress. CONCLUSION. Matching different length and tilting angle of the terminal implants led to variable stress reductions on implants, bone and the superstructure. By optimizing implant configuration, the reduction of stress on implants and surrounding bone could be maximized. Under the present condition, Tilt45-L was the preferred configuration. Further clinical testings are required.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1019-1021
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• 1992

This paper deals with the stress of the converters using the resonant switches. It is represented the reduction of the voltage and current stresses. According to the configuration of the multiple poly-phase converter. Especially, about buck ZVS-QRC it is studied the reduction of the voltage stress, and represented the result of simulation.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.5
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• pp.512-521
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• 1997

This paper deals with an evaluation of the residual stress due to shot peening induced in a car¬burized gear tooth and its application to the fatigue crack propagation problem. The residual stress is estimated based on the assumption that the main cause of residual stress is the volume difference between the case and core due to martensitic transformation in cooling, and the influ¬ence of both the reduction of retained austenite and the strain in the surface layer induced by shot peening are considered. The reliability of the method is examined by comparison with stresses measured by the X-ray diffraction method. The stresses intensity factors are computed by the influence function method and the reduction of the factor due to the residual stress is demonstrat¬ed and discussed based on the fracture mechanics.

• The Journal of Information Systems
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• v.29 no.1
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• pp.23-50
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• 2020

Purpose As information management grows in importance around the world, organizations are investing in information security technology. However, the higher the level of information security technology in an organization, the higher the techno-stress of employees. The purpose of this study is to suggest stress factors related to information security technology that affect the reduction of employees' intention to comply with information security and to suggest ways to alleviate stress. Design/methodology/approach The research presented a model for mitigating technical stress related to information security based on technical stress theory and person-organization fit theory. 346 questionnaire data were analyzed from the members of the organization who applied the information security technology, and the research hypothesis was verified through the structural equation modeling. Findings The hypothesis test confirms that security-related techno-stress reduces the information security compliance intention of employees, organizational technical support mitigates technical stress, and person-organization fitness mitigates the negative relationship between techno-stress and compliance intention. The results of the study contribute to the organization's strategy for minimizing the reduction of the information security compliance intention of employees, and are meaningful in that the theoretical basis for mitigating techno-stress is provided in the field of information security.

• Perspectives in Nursing Science
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• v.16 no.2
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• pp.65-74
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• 2019

Purpose: This study applied the Korean Mindfulness-Based Stress Reduction (K-MBSR) program for mothers of children and adolescents with mental illnesses, and verified its effectiveness on perceived stress and depression based on the Middle-range theory of caregiver stress. Methods: A quasi-experimental, non-equivalent control group pre-post test design was used. The K-MBSR program was reconstructed with experts' advice to adjust subjects' characters. Using a group approach, sessions were conducted once a week for six weeks, and each session took 2.5 hours. Results: The experimental group did not show a significant decrease in perceived stress than the control group. However, the experimental group showed a significant decrease in depression than the control group. Conclusion: The K-MBSR program was effective for depression. Future studies on high-stress groups or with an extended program are necessary to clarify the effects of the K-MBSR program on perceived stress. These results are consistent with the middle-range theory of caregiver stress, the theoretical framework of this study. When caregivers have similar inputs, proper intervention can change the control process. Further, it can be assumed that this change positively affects the output.

• Transactions of Materials Processing
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• v.17 no.4
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• pp.272-277
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• 2008

A constitutive equation of the electrical steel strip used for a raw material of transformer is proposed. The stress-strain behavior of electrical steel strip is quite different from that of common carbon steel and/or alloy steel. A series of tensile tests were performed with the specimens made from cold rolled strip. Several thicknesses of the strip were produced by a two-high (with upper and lower rolls) cold rolling pilot mill as reduction ratio increases from 10% to 90%. Its initial thickness of the strip was 2.5mm. Tensile specimens are cut out from the cold rolled strips. Mechanical properties of the steel are examined through rolling direction. Ramberg-Osgood model and the proposed equation are combined to describe the total behavior of stress-strain including instability region. The stress-strain curves calculated from the present constitutive equation are compared with those from experimentally obtained at each test condition of reduction ratios of specimen. Results show that the predicted stress-strain curves are in overall in a good agreement with measured ones.

• Structural Engineering and Mechanics
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• v.65 no.2
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• pp.129-139
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• 2018

Post-tensioning (PT) tendons are commonly used for the assembly of modularized concrete members, and tension is applied to the tendons during construction to facilitate the integrated behavior of the members. However, the tension in a PT tendon decreases over time due to steel corrosion and concrete creep, and consequently, the stress on the anchor head that secures the PT tendon also diminishes. This study proposes an automatic detection system to identify tension reduction in a PT tendon using pulsed-eddy-current (PEC) measurement. An eddy-current sensor is installed on the surface of the steel anchor head. The sensor creates a pulsed excitation to the driving coil and measures the resulting PEC response using the pick-up coil. The basic premise is that the tension reduction of a PT tendon results in stress reduction on the anchor head surface and a change in the PEC intensity measured by the pick-up coil. Thus, PEC measurement is used to detect the reduction of the anchor head stress and consequently the reduction of the PT tendon force below a certain threshold value. The advantages of the proposed PEC-based tension-reduction-detection (PTRD) system are (1) a low-cost (< $ 30), low-power (< 2 Watts) sensor, (2) a short inspection time (< 10 seconds), (3) high reliability and (4) the potential for embedded sensing. A 3.3 m long full-scale monostrand PT tendon was used to evaluate the performance of the proposed PTRD system. The PT tendon was tensioned to 180 kN using a custom universal tensile machine, and the tension was decreased to 0 kN at 20 kN intervals. At each tension, the PEC responses were measured, and tension reduction was successfully detected.

• Journal of Industrial Convergence
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• v.19 no.1
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• pp.87-97
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• 2021

This study aimed to systematically review the literature on the stress reduction of meaning-centered therapy (MCT) studies in Korea and to identify the characteristics of MCT for stress reduction. MCT studies aimed at reducing stress symptoms were searched among peer reviewed journal articles and unpublished dissertations until April, 2020. Two independent researchers assessed the risk of bias and the quality of the report using Scottish Intercollegiate Guidelines Network criteria. As a result of searching with 7 databases, 7 studies were finally selected. Seven MCTs were for all age groups, and 5 studies reported MCT was effective in reducing stress symptoms. Both single and combined type interventions were effective in reducing stress symptom, Researchers used the combined MCT more than single MCT program. The study with no significant effect was related to school test stress. There is a need to develop MCTs suitable for school-age youth with test stress in the future.