• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.6
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• pp.270-285
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• 2018

The behavior of wave-induced pore water pressure inside the rubble mound and seabed, and the resultant structure failure are investigated, which are used in design of the composite breakwater representing the coastal and harbor structures. Numerical simulation techniques have been widely used to assess these behaviors through linear and nonlinear methods in many researches. While the combination of strongly nonlinear analytical method and turbulence model have not been applied yet, which can simulate these characteristics more accurately. In this study, olaFlow model considering the wave-breaking and turbulent phenomena is applied through VOF and LES methods, which gives more exact solution by using the multiphase flow analytical method. The verification of olaFlow model is demonstrated by comparing the experimental and numerical results for the interactions of regular waves-seabed and regular waves-composite breakwater-seabed. The characteristics of the spatial distributions of horizontal wave pressure, excess-pore-water pressure, mean flow velocity and mean vorticity on the upright caisson, and inside the rubble mound and seabed are discussed, as well as the relation between the mean distribution of vorticity size and mean turbulent kinetic energy. And the stability of composite breakwater are also discussed.

• The Journal of the Korea Contents Association
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• v.21 no.10
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• pp.550-563
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• 2021

This study recognizes that the externalizing problem behaviors of child with disabilities are the result of the social interaction between mother and child, and empirically verifies its systematic causal structure and multidimensional influence relationship. It was attempted to derive practical implications that can help the smooth normalization process of children's families. Therefore, 135 children with disabilities and their mothers selected by convenience sampling were targeted, and in the relationship between maternal overprotective parenting and externalizing behaviors of child, effortful control was used as a mediating variable, and defense style of mothers and children was used as a moderating variable. A Conditional Process Analysis(CPA) that can verify the moderated mediation Effect was performed by establishing a research model. As a result of the analysis, first, the overprotective parenting behavior of mother was statistically significant in both direct and indirect effects in increasing externalizing behaviors of child, and the mediation effect by effortful control was also statistically significant. Second, it was confirmed that the moderated mediation effect of effortful control by the mother's defense style was statistically significant, and the moderated mediation effect of effortful control by the child's defense style was not statistically significant. Based on the above results, assuming the importance of the influence of maternal parenting, a direct strategy for change in maternal overprotective parenting, child's Practical implications of parallel strategies with the tendency toward effective control and suboptimal strategies through the application of mothers' coping strategies were discussed.

• Korean Journal of Construction Engineering and Management
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• v.22 no.5
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• pp.73-85
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• 2021

This study proposes an efficient management direction for Korean construction accident cases through a deep learning-based text data classification model. A deep learning model was developed, which categorizes five categories of construction accidents: fall, electric shock, flying object, collapse, and narrowness, which are representative accident types of KOSHA. After initial model tests, the classification accuracy of fall disasters was relatively high, while other types were classified as fall disasters. Through these results, it was analyzed that 1) specific accident-causing behavior, 2) similar sentence structure, and 3) complex accidents corresponding to multiple types affect the results. Two accuracy improvement experiments were then conducted: 1) reclassification, 2) elimination. As a result, the classification performance improved with 185.7% when eliminating complex accidents. Through this, the multicollinearity of complex accidents, including the contents of multiple accident types, was resolved. In conclusion, this study suggests the necessity to independently manage complex accidents while preparing a system to describe the situation of future accidents in detail.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.6
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• pp.419-426
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• 2020

The structural design of the steel eccentrically braced frame (EBF) was developed and analyzed in this study through multiobjective optimization (MOO). For the optimal design, NSGA-II which is one of the genetic algorithms was utilized. The amount of structure and interfloor displacement were selected as the objective functions of the MOO. The constraints include strength ratio and rotation angle of the link, which are required by structural standards and have forms of the penalty function such that the values of the objective functions increase drastically when a condition is violated. The regulations in the code provision for the EBF system are based on the concept of capacity design, that is, only the link members are allowed to yield, whereas the remaining members are intended to withstand the member forces within their elastic ranges. However, although the pareto front obtained from MOO satisfies the regulations in the code provision, the actual nonlinear behavior shows that the plastic deformation is concentrated in the link member of a certain story, resulting in the formation of a soft story, which violates the capacity design concept in the design code. To address this problem, another constraint based on the Eurocode was added to ensure that the maximum values of the shear overstrength factors of all links did not exceed 1.25 times the minimum values. When this constraint was added, it was observed that the resulting pareto front complied with both the design regulations and capacity design concept. Ratios of the link length to beam span ranged from 10% to 14%, which was within the category of shear links. The overall design is dominated by the constraint on the link's overstrength factor ratio. Design characteristics required by the design code, such as interstory drift and member strength ratios, were conservatively compared to the allowable values.

• Korean Journal of Construction Engineering and Management
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• v.22 no.1
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• pp.63-71
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• 2021

The construction guarantee market is a rear market affected by changes in the construction industry and market. As the restructuring of the construction industry's production system is being carried out, such as the abolition of regulations on business field between general and specialty contractors, major changes are expected not only in the construction market but also in the construction guarantee market. In construction guarantee market, there are currently three Contractor Financial Cooperatives, which are divided based on business field and business type(General, Specialty and Plant & Mechanical). The abolition of business field regulation will have various effects on construction guarantee market, such as forming a competitive structure among the three Contractor Financial Cooperatives. Therefore the role of the construction guarantee institutions are also required to change. This study predicted the changes in the construction guarantee market after the restructuring of construction industry and analyzed the ripple effect on the market. This study reviewed the details of the reorganization plan on the construction industry, policies and statistical data related to construction guarantee, and lastly conducted the survey on each member of the three Contractor Financial Cooperatives to analyze the usage behavior in the future guarantee market. Based on the result of this study, the members of both the General Contractor Financial Cooperative and Specialty Contractor Financial Cooperative are not willing to change the existing institutions, but a lot of them are expected to use other institutions in duplicate. The members of the Plant & Mechanical Contractor Financial Cooperative are most willing to use other guarantee institutions.

• Journal of the Korean GEO-environmental Society
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• v.12 no.7
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• pp.5-12
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• 2011

When choosing the support pattern of tunnel, the characteristics of rock are identified from the result of the surface geologic survey, boring, and geophysical prospecting and laboratory test. And a rock mass rating is classified and excavation method and standard support pattern are designed considering rock classification, domestic and international construction practices, numerical analysis. According to the revised design standard for tunnel, it was recommended to classify the rock mass rating for the design of tunnel into a rating based on RMR. If necessary, it proposed a flexible standard allowed applying more atomized the rock mass rating and Q-System. Also, the resonable verification of the support pattern must be accompanied because the factors affecting the structure and behavior of ground during the construction of tunnel are the main factors of uncertainty factors such as the nature of ground, ground water and the characteristics of structural materials. These days, such verification method is getting more specialized and diversified. In this study, the empirical method, numerical analysis and comparative analysis of in situ measurements were used to prove the reasonableness in the support pattern by RMR and Q-value on the Imha Dam emergency spillway.

• Journal of Korean Society of Forest Science
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• v.100 no.3
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• pp.402-407
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• 2011

The objectives of this study were to analyze the crown vertical structure, crown bulk density, and to develop regression models for predicting crown fuel load using the data from 10 destructively sampled Pinus densiflora trees in Bonghwa, Gyeongbuk. The fuel loads were observed higher in the middle portion of the vertical distribution of crown followed by the lower portion and upper portion of Pinus densiflora, respectively. Approximately 25% crown fuel load was found in the needle while 33% was observed in the branches with <1 cm diameter with a total of 58% available fuel loads. The average crown bulk density was $0.45kg/m^3$, and $0.27kg/m^3$ of this was available in the needles and branches with <1 cm diameters. The resulting models in linear equations were able to account for 84% and 88% of the observed variation, while the allometric equations with diameter at breast height as the single predictor showed better results to account for 90% and 95% of the observed variation in the available crown fuel loads and total crown fuel loads, respectively. The suggested equations in this study could provide quantitative fuel load attributes for crown fire behavior models and fire management of red pine stands in Bonghwa areas.

• (The)Study of the Eastern Classic
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• no.43
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• pp.305-328
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• 2011

This study examines a study of communication factor in the Chinese augury bone, as a communication text, a communication history text and a communication thought text, in terms of sender message channel audience effects, interdisciplinary research. In many respects, it is generally accepted that the Chinese augury bone have been the generic references of the Oriental culture. Based on various research results about The Chinese augury boney as a communication text, this paper explores factors of communication text related with meta-communication as the definition of communication and a structure of communication, a method of communication. The Chinese augury bone consider graphic element as communication tool, its manager as sender or communicator, the record as message, the bone as channel, its reader as audience, text understanding and behavior as effects, the augury bone producer as journalist, the tying bone in a bundle as old style book. In the Chinese augury bone, one property of communication thought is that the political ideology, which is related to the strong and weak of the graphic style and determines the naming method of kings.

• The Journal of the Korea Contents Association
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• v.21 no.1
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• pp.531-540
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• 2021

As cyber attacks and crimes increase exponentially and hacking attacks become more intelligent and advanced, hacking attack methods and routes are evolving unpredictably and in real time. In order to reinforce the enemy's responsiveness, this study aims to propose a method for developing an artificial intelligence-based security control platform by building a next-generation security system using artificial intelligence to respond by self-learning, monitoring abnormal signs and blocking attacks.The artificial intelligence-based security control platform should be developed as the basis for data collection, data analysis, next-generation security system operation, and security system management. Big data base and control system, data collection step through external threat information, data analysis step of pre-processing and formalizing the collected data to perform positive/false detection and abnormal behavior analysis through deep learning-based algorithm, and analyzed data Through the operation of a security system of prevention, control, response, analysis, and organic circulation structure, the next generation security system to increase the scope and speed of handling new threats and to reinforce the identification of normal and abnormal behaviors, and management of the security threat response system, Harmful IP management, detection policy management, security business legal system management. Through this, we are trying to find a way to comprehensively analyze vast amounts of data and to respond preemptively in a short time.

• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.83-90
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• 2021

In this study, effects of the physical and chemical properties of low temperature heated carbon on electrochemical behavior as a secondary battery anode material were investigated. A heat treatment at 600 ℃ was performed for coking of petroleum based pitch, and the manufactured coke was heat treated with different heat temperatures at 700~1,500 ℃ to prepare low temperature heated anode materials. The physical and chemical properties of carbon anode materials were studied through nitrogen adsorption and desorption, X-ray diffraction (XRD), Raman spectroscopy, elemental analysis. Also the anode properties of low temperature heated carbon were considered through electrochemical properties such as capacity, initial Coulomb efficiency (ICE), rate capability, and cycle performance. The crystal structure of low temperature (≤ 1500 ℃) heated carbon was improved by increasing the crystal size and true density, while the specific surface area decreased. Electrochemical properties of the anode material were changed with respect to the physical and chemical properties of low temperature heated carbon. The capacity and cycle performance were most affected by H/C atomic ratio. Also, the ICE was influenced by the specific surface area, whereas the rate performance was most affected by true density.