• The Journal of Society for e-Business Studies
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• v.21 no.1
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• pp.33-63
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• 2016

The diffusion of smartphone has make people engaged in communication with mobile messenger in everyday life. To understand the rapid growth of mobile messenger usage, this study investigates the unique features of mobile messenger services as communication media. Based on the media synchronicity theory and literature about online communication, we identify the functional and emotional features of mobile messenger. In particular, this study demonstrates that functional and emotional features of mobile messenger would influence intimacy and fatigue. Also, intimacy and fatigue, as mediating variables, have an impact on user satisfaction and commitment toward mobile messenger service. The results of this study provide practical implications for mobile messenger providers and users which attempt to facilitate positive effect such as intimacy among users and reduce negative effect such as fatigue on mobile messenger communication.

• Proceedings of the KWS Conference
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• 1996.10a
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• pp.19-34
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• 1996

A review was made of fatigue failures of nuclear power plant components in Japan, which were experienced in service and during periodical inspection. No case has been recently reported of a service fatigue failure of a reactor pressure vessel itself, excluding nozzle corner cracks, that occurred many years ago. But, service fatigue failures have been occasionally experienced in piping systems, pumps, and valves, on which fatigue design seems to have been inadequately applied. The causes of fatigue failures can be divided into two categories: mechanical-vibration-induced fatigue and thermal-fluctuation-induced fatigue. Vibration-induced fatigue failure occurs more frequently than is generally thought. The lesson gleaned from the present survey is a recognition that a service fatigue failure may occur due to any one or a combination of the following factors: (1) lack of communication between designers and fabrication engineers, (2) lack of knowledge about a possibility of fatigue failure and poor consideration about the effects of residual stresses, (3) lack of consideration on possible vibration in the design and fabrication stages, and (4) lack of fusion or poor penetration in a welded joint.

• The Journal of the Convergence on Culture Technology
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• v.8 no.3
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• pp.589-594
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• 2022

In an acceleration of 'untact' society during the COVID-19 pandemic, video conferencing platforms have been provided to connect the isolated and to overcome the limit of having interpersonal relationships. While these services brought a great deal of benefits, they also increased the number of people who suffer from additional fatigue from video conferencing. This study, thus, aimed to identify the factors of using video conferencing services and further to examine the relationship between the factors and the users' overall fatigue. Through focus-group interviews and survey, four main factors of fatigue (restriction from untact communication, difficulty of use, background set-ups, discomfort from excessive attention) were identified. This study also found the positive relationships of restriction from untact communication and background set-ups on the users' overall fatigue. The results does not only provide implication on defining new fatigue factors from young generations but also help practitioners and service providers to improve the deficits of services that the real users currently experience.

• Advanced Composite Materials
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• v.17 no.3
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• pp.215-224
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• 2008

The present study aims to design a multilayer microstrip antenna with composite sandwich construction and investigate fatigue behavior of this multilayer SAS (surface antenna structure) that was asymmetric sandwich structure for the next generation of structural surface technology. This term, SAS, indicates that the structural surface becomes an antenna. Constituent materials were selected considering electrical properties, dielectric constant and tangent loss as well as mechanical properties. For the antenna performance, antenna elements inserted into structural layers were designed for satellite communication at a resonant frequency of 12.2 GHz. From electrical measurements, it was shown that antenna performances were in good agreement with design requirements. In cyclic 4-point bending, flexure behavior was investigated by static and fatigue test. Fatigue life curve of the SAS was obtained. The experimental results of bending fatigue were compared with single load level fatigue life prediction equations and in good agreement. The SAS concept is can be extended to give a useful guide for manufacturers of structural body panels as well as antenna designers.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.153-157
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• 1989

In this paper, a new method of Eye Movement Pattern Encoding (EMPE) which is based on electrooculography(EOG) was suggested for the purpose of effective communication between man and machine, instead of Point-Of-Regard-Selection (PORS) method. Also, ocular interface is designed and the typing aid, eye-pattern writer, was constructed for the test of theoretical validity and its practical aspect. Effect of eye fatigue on the performance of ocular interface was quantified through fatigue test.

• Structural Engineering and Mechanics
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• v.69 no.4
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• pp.407-416
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• 2019

This paper develops a wireless sensor for online fatigue crack detection and failure warning based on crack-induced nonlinear ultrasonic modulation. The wireless sensor consists of packaged piezoelectric (PZT) module, an excitation/sensing module, a data acquisition/processing module, a wireless communication module, and a power supply module. The packaged PZT and the excitation/sensing module generate ultrasonic waves on a structure and capture the response. Based on nonlinear ultrasonic modulation created by a crack, the data acquisition/processing module periodically performs fatigue crack diagnosis and provides failure warning if a component failure is imminent. The outcomes are transmitted to a base through the wireless communication module where two-levels duty cycling media access control (MAC) is implemented. The uniqueness of the paper lies in that 1) the proposed wireless sensor is developed specifically for online fatigue crack detection and failure warning, 2) failure warning as well as crack diagnosis are provided based on crack-induced nonlinear ultrasonic modulation, 3) event-driven operation of the sensor, considering rare extreme events such as earthquakes, is made possible with a power minimization strategy, and 4) the applicability of the wireless sensor to steel welded members is examined through field and laboratory tests. A fatigue crack on a steel welded specimen was successfully detected when the overall width of the crack was around $30{\mu}m$, and a failure warnings were provided when about 97.6% of the remaining useful fatigue lives were reached. Four wireless sensors were deployed on Yeongjong Grand Bridge in Souht Korea. The wireless sensor consumed 282.95 J for 3 weeks, and the processed results on the sensor were transmitted up to 20 m with over 90% success rate.

• Journal of the Korea Convergence Society
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• v.12 no.10
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• pp.235-248
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• 2021

The ultimate aim of this work is to explore the antecedents that affect the loneliness felt by users who actively communicate through smartphones apps. To do this, three characteristics including individual, relational, and communication characteristics that can affect loneliness and the effects of these characteristics on loneliness are empirically analyzed. The research results are as follows. First, we found that conflict resolution ability had a significant effect on interpersonal conflict and loneliness. Second, social stress was found to have a significant effect on interpersonal conflict, communication fatigue, and loneliness. Third, lack of communication was found to have a significant effect on conflict resolution ability and loneliness. Finally, we found that communication fatigue had a significant effect on loneliness. These results are interpreted that in order to reduce the loneliness, it is necessary to continuously improve the ability to wisely resolve conflicts that may arise in the relationship between oneself and others. In addition, it is necessary to reduce the fear or burden of building relationships with others.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.2 no.1
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• pp.17-22
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• 2009

In this paper, we extract well-known parameters such as zero crossing rate(ZCR), low band energy(Band) and median frequency(MDF) from surface electromyogram (EMG), and compare to evaluate themselves as measures for fatigue. In experiments, 3 males and 3 females volunteered to participate in surface EMG recordings placed on the biceps brachii and each recording experiment continued until exhaustion.

• Smart Structures and Systems
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• v.13 no.6
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• pp.943-957
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• 2014

When subjected to fatigue loading, the main failure mode of partially prestressed concrete (PPC) structure is the fatigue fracture of tensile reinforcement. Therefore, monitoring and evaluation of the steel stresses/strains in the structure are essential issues for structural design and healthy assessment. The current study experimentally investigates the possibility of using fiber Bragg grating (FBG) sensors to measure the steel strains in PPC beams in the process of fatigue loading. Six full-scale post-tensioned PPC beams were exposed to fatigue loading. Within the beams, the FBG and resistance strain gauge (RSG) sensors were independently bonded onto the surface of tensile reinforcements. A good agreement was found between the recorded results from the two different sensors. Moreover, FBG sensors show relatively good resistance to fatigue loading compared with RSG sensors, indicating that FBG sensors possess the capability for long-term health monitoring of the tensile reinforcement in PPC structures. Apart from the above findings, it can also be found that during the fatigue loading, there is stress redistribution between prestressed and non-prestressed reinforcements, and the residual strain emerges in the non-prestressed reinforcement. This phenomenon can bring about an increase of the steel stress in the non-prestressed reinforcement.

• Journal of the Korea Convergence Society
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• v.10 no.8
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• pp.21-26
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• 2019

This paper proposes a fatigue recognition method using the C4.5 algorithm. Based on domestic and international studies on fatigue evaluation, we have completed the fatigue self - assessment scale in combination with lifestyle and cultural characteristics of Chinese people. The scales used in the text were applied to 58 sub items and were used to assess the type and extent of fatigue. These items fall into four categories that measure physical fatigue, mental fatigue, personal habits, and fatigue outcomes. The purpose of this study is to analyze the leading causes of fatigue formation and to recognize the degree of fatigue, thereby increasing the personal interest in fatigue and reducing the risk of cerebrovascular disease due to excessive fatigue. The recognition rate of the fatigue recognition system using the C4.5 algorithm was 85% on average, confirming the usefulness of this proposal.