• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.249-252
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• 2006

When concrete is subjected to uniaxial compression, the failure process is normally initialed from a localized zone. The localization of failure governs structural behaviors of concrete. In this paper, the compressive strength and failure behavior of recycled coarse aggregate concrete with different replacement level of recycled coarse aggregates are investigated using acoustic emission(AE). AE characteristics of concrete were investigated during the entire loading period. For these purpose, four recycled coarse aggregate replacement level (i.e 0%, 30%, 60% and 100%) were considered in this paper. Result from this study show AE signal, AE method can apply to investigate a compressive failure mode according to recycled coarse replacement level.

• Journal of Korean Institute of Industrial Engineers
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• v.14 no.2
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• pp.81-90
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• 1988

This paper is concerned with warranty cost models for a product with two types of failure ; type 1 failures corrected by minimal repair and type 2 failures removed only by replacement. Two warranty policies involving an initial free service period followed by a pro-rata period are considered ; the difference is whether the warranty is renewed or not when type 2 failure occures during its free service period. Expected warranty costs under the two policies are obtained, and their behaviors are examined for the case where type 1 and 2 failure distributions are Weibull and exponential, respectively.

• Tunnel and Underground Space
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• v.16 no.4 s.63
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• pp.313-325
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• 2006

In this study, scaled model tests were performed to investigate the deformation behaviors around tunnels located in anisotropic rocks. Fifteen types of test models which had respectively different joint angles and rock pressure conditions were made, where the modelling materials were the mixture of sand, plaster and water. All of the tested models showed the shear failure mechanism at the stress-concentrated regions and sliding phenomena according to the joint planes. The direction of joint inclination turned out to have great effect on the tunnel deformation behaviors. The models of joint inclination less than $30^{\circ}$ showed considerable floor heavings. The model of $50^{\circ}$ joint inclination showed the least tunnel convergence among the tested models regardless of rock pressure condition, so that it was thought as the most stable model. Furthermore, the failure mechanisms and deformation behaviors of tunnel models were strongly dependent on the coefficient of rock pressure.

• Journal of the Korean GEO-environmental Society
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• v.17 no.3
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• pp.27-35
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• 2016

Even if the various data analyzing methods were suggested to examine the measured slope behaviors, it is difficult to find methods or procedures for connecting the analyzed results of slope stability and measured slope data. This research suggests the analyzing methods combing the stability analysis and measured data based on progressive failure of slope. Slope failure analysis by time degradation were calculated by strength parameters composed of strength reduction coefficients, also which were compared to the measured data according to the variations of safety factor and displacement of slopes. The accumulated displacement curve were shown as 3rd degree polynomials by suggested procedures, which was the same as before researches. The reverse displacement velocity curves were shown as linear function for prediction of brittle slope failures, also they were shown as 3rd degree polynomials for ductile slope failures, which were the same as the suggested equation by Fukuzono (1985) and they were very similar behaviors to the in-situ failure cases.

• International journal of steel structures
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• v.18 no.4
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• pp.1350-1362
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• 2018

Full-scale experimental study and numerical analysis on behaviors and failure mechanisms of full high strength steel extended endplate connections in fire have been carried out and presented in this paper. The experimental behaviors of the connections were compared with the provisions of Eurocode 3. The test results show that the failure modes of the connections in fire are bolt failure with yielding of the flange, as same as those at ambient temperature. The failures of the bolts in fire are ductile while they are brittle at ambient temperature. The rotation capacity of the connections in fire is proved sufficient. What is more, at elevated temperature $550^{\circ}C$, the plastic moment resistances of Q690 and Q960 full high strength steel endplate connections are only 40% of those at ambient temperature, while their initial rotation stiffness are 66 and 63% respectively. But the rotation capacities of Q690 and Q960 high strength steel endplate connections are 1.38 and 1.74 times of those at ambient temperature. Moreover, it is found that the component method Eurocode 3 proposed based on connections made of mild steels can be used to calculate plastic resistances and to predict failure modes of high strength steel endplate connections in fire, but it is not suitable to predict their stiffness. The suggestions about rotation capacity of connections in Eurocode 3 are found too conservative for high strength steel endplate connections in fire.

• The Korean Journal of Franchise Management
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• v.11 no.3
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• pp.19-26
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• 2020

Purpose: The old axion to put the customers first (e.g., customers are king, customers are always right) has been taken for granted in the service sector. In addition, many companies in South Korea are providing customer-first education for employees at their contact points to strengthen their competitiveness. However, excessive increase in the psychological power of the customer can lead to a problem of abuse of power, called 'Gap-jil.' Despite these concerns, most companies hardly discard policies to give high priority to customers because of the assumption that it enhances customer satisfaction leading to organizational performance. However, in recent years, some franchise catering companies have posted warnings about the abuse of power by customers, and a movement to pursue a power-balancing between service providers and their customers is spreading. Research design, data, and methodology: This research is conducted to reconsider the principle of the customer-first perspective and to create a basis for arguments that can solve the problem of abuse of power, which is recognized as a serious social problem. In this research, we test and analyze the effect of customers' psychological power in the context of a restaurant on expectation for service and response to service failure. Result: The result of an experimental study shows that the effect of psychological power on customer satisfaction can be somewhat negative. Also, customers with high psychological power are more likely to have high service expectations. Especially high psychological power of customers causes a difference in the expectation level of human factors such as employee attitude, while the difference in expectations of non-human factors such as restaurant atmosphere was not statistically significant. In addition, when customers with high psychological power encounter service failure situation, they are more likely to feel disappointment and regret with a service provider. Meanwhile, the effect of psychological power on complaining behaviors are not significant. Conclusions: The findings of this research provide meaningful implications that the service providers should reconsider their existing corporate culture and management policies that put customers first. In addition, the result of this research is provided meaningful opportunities to review the management philosophy for the company's customers and the education philosophy for the employee education.

• Journal of Korean Biological Nursing Science
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• v.18 no.4
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• pp.247-256
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• 2016

Purpose: This study aimed to examine the relationships between the N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels with the sociodemographic and clinical factors, self-care behaviors, and the physical symptom experiences in patients with heart failure. Methods: This cross-sectional study utilized a convenience sample of adult outpatients and inpatients who attended a cardiology department in a tertiary hospital in Seoul, Korea. The data from 154 patients with heart failure were collected using a questionnaire, and their clinical data were extracted from their electronic medical records. Results: Compared with the patients with high NT-proBNP levels, those with low NT-proBNP levels had significantly lower physical symptom experiences scores. Patients with low- and mid-NT-proBNP levels were more likely to be employed compared with those with high NT-proBNP levels. Patients with low NT-proBNP levels had higher left ventricular ejection fractions, and were less likely to have arrhythmias and comorbidities. Conclusion: The results from this study showed that patients with more severe heart failure had higher physical symptom experiences scores; hence, individualizing treatment approaches based on heart failure severity is necessary.

• Steel and Composite Structures
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• v.25 no.1
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• pp.35-43
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• 2017

This paper presents the findings of experimental and numerical investigations on failure analysis and structural behavior of notched steel I-beams reinforced by bonded Carbon Fiber Reinforced Polymer (CFRP) plates under static load. To find solutions for preventing or delaying the failures, understanding the CFRP failure modes is beneficial. One non-strengthened control beam and four specimens with different deficiencies (one side and two sides) on flexural flanges in both experimental test and simulation were studied. Two additional notched beams were investigated just numerically. In the experimental test, four-point bending method with static gradual loading was employed. To simulate the specimens, ABAQUS software in full three dimensional (3D) case and non-linear analysis method was applied. The results show that the CFRP failure modes in strengthening of deficient steel I-beams include end-debonding, below point load debonding, splitting and delamination. Strengthening schedule is important to the occurrences and sequences of CFRP failure modes. Additionally, application of CFRP plates in the deficiency region prevents crack propagation and brittle failure.

• Journal of Distribution Science
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• v.22 no.2
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• pp.103-113
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• 2024

Purpose: With the popularity of artificial intelligence (AI) in the service industry and occurrence ofservice failures in AI-based services, understanding human-robot interaction issues in service failure situations is especially important. Some issues which deserve further empirical investigation are whether consumers can develop the same tolerance for chatbots after service failure as they have for human agents, and the relationship between agent type and tolerance is mediated by the mechanisms of perceived warmth and perceived competence. Research Design, Data, and Methodology: This research experimentally collected and analyzed data from 119 university students who had experienced chatbots service failures. Differences in tolerance towards human agents and chatbots after experiencing service failures were explored, with a further examination of the mediating pathways between this relationship via perceived warmth and perceived competence. Results: Consumers are more tolerant ofservice failure with chatbots compared to service failure with human agents. Significant mediation of the relationship between service agent and service failure tolerance by perceived competence, while perceived warmth has no significant mediating effect. Conclusions: This research enhances our understanding of AI-assisted services, human-computer interaction, improves the service functionality of existing smart devices, and deepens the understanding of the relationship between consumer responses and behaviors.

• Steel and Composite Structures
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• v.26 no.6
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• pp.759-769
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• 2018

This paper studies shear and tensile behaviors of headed stud connectors in double skin composite (DSC) structure. Firstly, 11 push-out tests and 11 tensile tests were performed to investigate the ultimate shear and tensile behaviors of headed stud in DSC shear wall, respectively. The main parameters investigated in this test program were height and layout of headed stud connectors. The test results reported the representative failure modes of headed studs in DSC structures subjected to shear and tension. The shear-slip and tension-elongation behaviors of headed studs in DSC structures were also reported. Influences of different parameters on these shear-slip and tension-elongation behaviors of headed studs were discussed and analyzed. Analytical models were also developed to predict the ultimate shear and tensile resistances of headed stud connectors in DSC shear walls. The developed analytical model incorporated the influence of the dense layout of headed studs in DSC shear walls. The validations of analytical predictions against 22 test results confirmed the accuracy of developed analytical models.