• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.6
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• pp.563-569
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• 2016

This paper presents the resizing method of columns and beams that considers column-to-beam strength ratios to simultaneously control the initial stiffness and ductility of steel moment frames. The proposed method minimizes the top-floor displacement of a structure while satisfying the constraint conditions with respect to the total structural weight and column-to-beam strength ratios. The design variable considered in this method is the sectional area of structural members, and the sequential quadratic programming(SQP) technique is used to obtain optimal results from the problem formulation. The unit load method is applied to determine the displacement participation factor of each member for the top floor lateral displacement; based on this, the sectional area of each member undergoes a resizing process to minimize the top-floor lateral displacement. Resizing members by using the displacement participation factor of each member leads to increasing the initial stiffness of the structure. Additionally, the proposed method enables the ductility control of a structure by adjusting the column-to-beam strength ratio. The applicability of the proposed optimal drift design method is validated by applying it to the steel moment frame example. As a result, it is confirmed that the initial stiffness and ductility could be controlled by the proposed method without the repetitive structural analysis and the increment of structural weights.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.2
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• pp.129-136
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• 2020

In this study, we develop a sampling-based seismic probabilistic risk assessment (SPRA) quantification technique that can accurately consider a partially dependent condition of component seismic fragility information. Specifically, the SPRA quantification method is proposed by combining the advantages of two representative methodologies: EPRI seismic fragility and JAERI seismic fragility input-based quantification. The most important feature of the proposed method is that it performs a SPRA using a sampling technique by transforming the EPRI seismic fragility input into JAERI seismic fragility input. When the proposed sampling-based approach was applied to an example of simple system and to a SPRA problem of a nuclear power plant, it was observed that the proposed method yields approximately similar system seismic fragility and seismic risk results as those of the exact solution. Therefore, it is believed that the approach proposed in this study can be used as a useful tool for accurately assessing seismic risks, considering the partial seismic dependence among the components; the existing SPRA method cannot handle such partial dependencies.

• Management & Information Systems Review
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• v.36 no.3
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• pp.113-130
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• 2017

This study examines the effect of direct investment in Asia on firm value for nonfinancial firms listed on KRX between 2006 and 2015. We also explore whether the mediating effects of cashholdings the relationship between direct investment in Asian markets and corporate value. Recently, companies are increasing their cash holdings for risk management. Cashholdings are causing agent problems, which has a negative impact on corporate value. In this case, when the company conducts active investment activities such as foreign direct investment, it is possible to supply the appropriate funds in a timely manner, thereby cashholdings increase the possibility of success of foreign direct investment and alleviate the agent problem of cash holdings. For the analysis, the number of directly invested firms in Korean listed firms is used as the explanatory variables for the Chinese and Vietnamese markets where foreign direct investment is the most active, and cash holding is set as the moderating variable. As a result, direct investment in China and Vietnam showed a positive (+) relationship with firm value, and cashholdings have a positive the relationship between foreign direct investment and firma value. The implications of this paper are as follows. First, it is suggested that the direct value of direct investment can be enhanced the relationship between direct investment and firm value in Asia. In addition, it can be suggested that cash holdings play a role of effective investment supply in firms that implement foreign direct investment, positively affecting corporate value.

• Journal of Digital Convergence
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• v.18 no.10
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• pp.59-80
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• 2020

The purpose of this study is to analyze the current problems with the recovery methods and support systems for harm caused by digital sexual assault, based on cases in the U.S., U.K., and Australia. The significance of this study is the implications on problem solving related to digital sexual assault based on the legislation and systems of advanced foreign nations. The analytical method behind this study is the investigation of research literature. The reference materials are from judicial precedents, comparative analysis on media data, experts' advisory conferences, study forums, foreign theses, and documents on law and policy. As shown by the results of this study, we need to examine digital sexual exploitation and seek countermeasures from the victim's perspective after comparing foreign cases to determine the best protections and support systems. As digital sexual content can spread indefinitely, we certainly recognize the inherent difference between digital sexual crimes and offline sexual crimes. Thus, each case needs to be professionally categorized and an appropriate punishment must be suggested that satisfies the victims' needs. Ultimately, this study is meaningful for suggesting preventive measures against digital sexual crimes.

• Journal of Digital Convergence
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• v.18 no.10
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• pp.325-334
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• 2020

This study was done to examine parents, peer, teacher attachment, depression, and self-conception in adolescents. A survey using a structured questionnaire was conducted with 2,3 grade students of middle school located in 137 subjects. Data were analyzed using an independent t-test, one-way ANOVA, Pearson's correlation, and multiple stepwise regression analysis with the SPSS WIN 22.0 program. There was a significant difference in parents attachment(F=13.878, p<.001), peer attachment(F=7.431, p<.001), teacher attachment(F=7.425, p<.001), depression(F=13.241, p<.001), and self-conception(F=13.136, p<.001) according to participants' school grades. In the correlations of study variables, self-conception showed statistically significant correlations with parents, peer and teacher attachment in aspects of positive, and depression in aspect of negative. Participants' depression explained 61% of variance in self-conception. Findings from this study should be useful in the development of programs to promote participants' self-concept through their depression as a major problem in adolescent mental health.

• Biomedical Science Letters
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• v.5 no.2
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• pp.191-200
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• 1999

In recent years continuously increasing number of tuberculosis (TB) cases due to the emergence of strains with multidrug resistance and AIDS is a significant global health problem. Therefore, more rapid and reliable diagnosis of TB may be one of the most urgent needs in efforts to eradicate the disease. The present study was designed to compare and assess the diagnostic values and efficiencies between the conventional methods (X-ray, AFB stain and culture) and PCR for pulmonary TB on 171 cases. Chest X-ray finding and clinical features revealed that 39 (22.8%) of 171 sputum specimens were pulmonary TB cases. The statistical data were taken on the basis of the definitive diagnosis: In X-ray, overall sensitivity, specificity, efficiency and false positive and false negative incidence was respectively 69.2%, 87.1％, 83.0%, 12.9%, and 30.8％； 79.5%, 95.5%, 91.8%,4.6％ and 20.5％ in AFB-stain; 56.4%, 99.2%,89.5%, 0.8% and 43.6% in culture; 82.1%, 96.2%, 93.0%, 3.8% and 17.9% in PCR. PCR got a highest sensitivity and efficiency as well as a lowest false negative incidence. Culture had a highest specificity with a lowest false positive incidence. These results imply that PCR assay is fast, sensitive and efficient method for diagnosis of pulmonary TB. However, combined use of the conventional methods with thorough quality control may offer more opportunities for detecting Mycobacterium tuberculosis and diagnosting TB although they have some limits.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.3 no.1
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• pp.29-55
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• 2008

The objective of Starts-up education rears leading company that minimize a risk & connect them with successful idea. Internet Starts-up education is serviced in public & civil parts, it is insufficient to reach successful Starts-up support. This study is targeting on review the present condition of the Internet Starts-up education, research which it sees Internet Starts-up education actual condition investigation through investigation student of education satisfactorily and education contents and the plan to grope an Starts-up education progress coat problem and developmental plan it did. The current events point which has become research result escape first, age of the students of education, followed in educational background and, education motive and education experience presence education satisfactory boat song it appeared in these demand different, base grudge the form which is various it fixed and the education was demanded. Second, currently the department of pedagogy joining in establishment leader against the technical element which is advanced swip, the education reinforcement against an enterprise accomplishment ability back human factor, an enterprise propulsion environment and an enterprise item back enterprise environment element was demanded. Time after support and consulting, completion lifestyle community construction, completion lifestyle for item connection support and the trade name net after third, establishing an enterprise we the king, after toe ring back educating which carries on shoulder the importance of the civil official was embossed. The study which it sees led and like this investigation analysis the education progress for the successful support of the Internet Starts-up and time after connection setup construction it led and the plan which it will put out advancement of Starts-up education and it groped.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.4
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• pp.451-460
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• 2014

In this paper, we examined the problem of the structural stability according to the patch load of a rectangular plate that reflects the material properties of A6082-T6 is used primarily for marine plant structure. it applied to the four patch loading shapes, the effect of aspect ratio, a boundary condition and calculated the critical elastic buckling load. Calculating the critical elastic buckling load, During the eigenvalue buckling analysis it is applied to the shell181 as 4 node shell element. when the plate subjected to patch loading compare to the plate under a uniform axial compression load, it is possible observed to occur the different elastic buckling behaviour and it could be confirmed that it is affected significantly on a variable position and type of loadings, such as the effect of the aspect ratio. Also, Critical elastic buckling load according to th patch loading type in simply supported rectangular plate a/b=1.0, ${\gamma}b$=200mm are calculated 67%(Loading type I), 119 %(Loading type II), 76 %(Loading type III), 160 %(Loading type IV), respectively. Loading type I and III could be determined with the strong elastic buckling behavior much more than Loading type II and IV.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.3
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• pp.307-313
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• 2010

In this study, alternative designs for the bends used in district heating pipes are investigated. The district heating pipes, which are subjected to temperatures of 10 to $120^{\circ}C$ and a water pressure of $16\;kgf/cm^2$, have to withstand thermomechanical cyclic loads when in use. These pipes comprise three concentric tubes: a steel pipe (internal), polyurethane (PUR) insulator (middle), and a high-density polyethylene (HDPE) case (external). In addition, the bends in the district heating pipe system are covered with foam pads that cause aging. In this study, an alternative bend design that does not involve the use of a foam pad is proposed to overcome the aging problem in the bends. In the proposed design, "shear rings" are added to the surface of a bend, and its dimensions are determined by a combination of the statistical (Taguchi) method and FEM. The geometrical parameters such as thickness, height, and number of the rings significantly affect the design optimization, and hence, they affect the results of the FEM.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.1
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• pp.29-35
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• 2012

The treatments for spinal canal stenosis are radicular cyst removal, spine fusion, and implantation of an artificial intervertebral disc. Artificial intervertebral discs have been most widely used since the mid-2000s. The study of artificial intervertebral discs has been focused on the analysis of the axial rotation, lateral bending, the degrees of freedom of the disc, and flexion-extension of the vertebral body. The issue of fatigue failure years after the surgery has arisen as a new problem. Hence, study of artificial intervertebral discs must be focused on the fatigue failure properties and increased durability of the sliding core. A finite element model based on an in the artificial intervertebral disc (SB Charit$\acute{e}$ III) was produced, and the influence of the radius of curvature and the change in the coefficient of friction of the sliding core on the von-Mises stress and contact pressure was evaluated. Based on the results, new artificial intervertebral disc models (Models-I, -II, and -III) were proposed, and the fatigue failure behavior of the sliding core after a certain period of time was compared with the results for SB Charit$\acute{e}$ III.