• Composites Research
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• v.23 no.2
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• pp.1-9
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• 2010

This study analyzes the apparent fracture toughness of a thick-walled cylinder with a functionally graded material (FGM) coating at the inner surface of the cylinder. The cylinder is assumed to have a single radial edge crack emanating from its inner surface. The crack surfaces and the inner surface of the cylinder are subjected to an internal pressure. The incompatible eigenstrain developed in the cylinder due to nonuniform coefficient of thermal expansion as a result of cooling from sintering temperature is taken into account. Based on a method of evaluating stress intensity factor introduced in our previous study, an approach is developed to calculate apparent fracture toughness. The approach is demonstrated for a cylinder with a TiC/$Al_{2}O_{3}$ FGM coating and some numerical results of apparent fracture toughness are presented graphically. The effects of material distribution profile, cylinder wall thickness, application temperature, and coating thickness on the apparent fracture toughness are investigated in details. It is found that all of these factors play an important role in controlling the apparent fracture toughness of the cylinder.

• Journal of Korean Tunnelling and Underground Space Association
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• v.8 no.3
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• pp.259-271
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• 2006

This paper aims to predict the corrosion of a fully cement-grouted rockbolt induced by chloride diffusion in a cement mortar grout. From the viewpoint of the long-term durability, a rockbolt may be deteriorated by chemical components, such as sulphate and chloride, in groundwater. Especially, the steel rod of a rockbolt is corroded mainly by chloride. The rockbolt corrosion results in the volume expansion of a rod and then the cracking of a cement grout. In this study, the chloride diffusion coefficient of a cement mortar grout was used to evaluate the possibility of rockbolt corrosion by chloride, and to predict the long-term durability of a rockbolt. The electric acceleration test method was adopted to measure the chloride diffusion coefficient. In addition, a simple pullout testing system was newly proposed to measure the pullout capacity of a rockbolt more easily in a laboratory condition. From the experiments, it was showed that the chloride could diffuse in the cement grout more easily than in ordinary concrete materials. As a result, it was considered that a rockbolt might be easily corroded in a short term by the diffusion of chemical components with high concentration, although it was fully grouted.

• Geomechanics and Engineering
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• v.19 no.5
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• pp.421-434
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• 2019

It is of great significance to study the mechanical properties and failure mechanism of the defected rock for geological engineering. The defected sandstone modeling with power-law distribution of pre-cracks was built in this paper by Particle Flow Code software. Then the mechanical properties of sandstone and the corresponding failure process were meticulously analyzed by changing the power-law index (PLI) and the number of pre-cracks (NPC). The results show that (1) With the increase of the PLI, the proportion of prefabricated long cracks gradually decreases. (2) When the NPC is the same, the uniaxial compressive strength (UCS) of sandstone increases with the PLI; while when the PLI is the same, the UCS decreases with the NPC. (3) The damage model of rock strength is established based on the Mori-Tanaka method, which can be used to better describe the strength evolution of damaged rock. (4) The failure mode of the specimen is closely related to the total length of the pre-crack. As the total length of the pre-crack increases, the failure intensity of the specimen gradually becomes weaker. In addition, for the specimens with the total pre-crack length between 0.2-0.55 m, significant lateral expansion occurred during their failure process. (5) For the specimens with smaller PLI in the pre-peak loading process, the concentration of the force field inside is more serious than that of the specimens with larger PLI.

• Journal of Digital Convergence
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• v.12 no.2
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• pp.483-493
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• 2014

In a modern society where various kinds of cultures coexist, kidult culture seeking something pleasant and interesting in the adult culture has made an appearance affected by pop art. The goal of this study is to help the kidult culture carrying on the feature of pop art to promise a bright future in the consumer market and to help kidult marketing through the expansion of globalization of kidult culture goods. The first study method was to refer to the theoretical research material like theses or academic journals to analyze the feature of pop art and cultural phenomenon. The second one was to analyze media reports, TV programs, movies, and ads currently in issue about kidult cultures in news, media data, and internet materials to feel the kidult cultural phenomenon at the moment. The result of this study shows that, especially, popularity, vividness, and sense of humor and wit among the features of pop art have a great influence on the kidult culture. As a result, Firstly, We can expect a vitalization in the consumer market through qualitative and quantitative improvement of kidult consumer culture. Secondly, We should make an effort to expand kidult consumer culture by developing various kinds of culture goods for each age groups. Thirdly, Domestic companies should open up an adult consumer market with self-developed character products. Fourthly, We should make an aggressive marketing strategy for kidult culture goods in the world market in the flow of Hallyu.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.80-97
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• 2010

With the hubbing strategy, construction of "Incheon Airport Railroad(AREX)" was proceeded to expand the accessibility at the level of airports in rivalry like Kansai and Chek Lap Kok. At the present 1st phase which routes from Incheon Airport to Kimpo Airport is opened March 2007. 2nd phase which is planned from Kimpo Airport to Seoul station will be opened at the end of October 2010. But the accessibilty to AREX is delinquent because it is connected only in Seoul station and the maximum operation speed is 110km/h which downgrade the time competitiveness with airport limousine. In addition, transfering of user is necessary to access to AREX from Kyungbu KTX. With these reasons, travel demand in 1st phase section is low(7%). According to reestimation of travel demand, demand analysis result compared with convention condition is insufficient, so required annual average government grant-in-aid amounts to 200 billions won, and it is right time to develop the method for revitalization of Incheon airport railroad. In this paper, facilities plan and operating plan to make new travel demand by speed-up which is able through substitution train now running with high speed train(EMU, 180km/h) and direct connection of KTX, will be suggested. This will contribute to offering high speed railroad service to customers and the reduction of government grant-in-aid by way of demand expansion.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.234-234
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• 2017

Recent abnormal weather, especially continued rainfall during sowing season causes difficulty in proper sowing of wheat and delayed sowing after November 15 is concerned about freezing damage during winter, resulting in reduction of wheat yield. To correspond government policy of crop sufficiency improvement and produce and supply raw wheat and barley steadily, expansion of cultivation area is necessary and spring sowing of wheat is required. To obtain basic information on the improvement of spring sown wheat and barley production, comparison and path coefficients analysis was conducted for yield and yield related components from autumn and spring sown wheat and barley. Path analyses were known as very useful in clarifying the effects of yield components on grain yield formation, which were not accurately reflected in simple correlation anaylses. Most cultivated 5 wheat and 9 barley cultivars were sown on October and February at Cheon-ju province according to standard sowing method. For the spring sowing of wheat and barley, the varieties having vernalization degree I~III are seeded in the mid of February and seeding rate is 200~250kg/ha which is increased by 25% than autumn sowing. N-fertilizer of 95 kg/ha and the same amount of P, K dressed in autumn are applied at once as basal fertilizer. The magnitude of direct effect in each yield components on yield was in sequence as follows. In autumn wheat, grain number per $spike{\geq}$ the number of spike per $m^2$>1000-grain weight and in spring wheat, grain number per $ spike{\geq}the$ number of spike per $m^2$> 1000-grain weight. In autumn naked barley, 1000-grain weight> the number of spike per $m^2$, grain number per spike and in spring barely, the number of spike per $m^2$> grain number per spike > 1000-grain weight. In autumn covered barley, grain number per spike>the number of spike per $m^2$ and in spring coverd barley, the number of spike per $m^2$> grain number per spike, 1000-grain weight. In autumn malt barley, the number of spike per $m^2$>1000-grain weight and in spring malt barley, the direct effects of three yield components were similar. According to the path analysis of yield components for spring sown wheat and barley, it was suggested that adequate number of spike per $m^2$ was most important factor for yield increase.

• Korean Security Journal
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• no.31
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• pp.125-155
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• 2012

Terrorist organization has shown the trend of secret organization and it is harder to cope with terrorism because of uncertainty of terrorism. Homegrown terrorism is the one, whose preparation, execution and effect are restricted to domestic area. By the way, in the worldwide economic depression, violence and radical demonstration have shown the expansion trends as in Middle East, political revolution of Africa, anti-social resistance of Europe and Wall Street Occupation of USA. Homegrown terrorism is occurring in various countries such as UK and Spain as well as USA. Specialists warn homegrown terrorism in Korea. The purpose of this study was to prospect the possibility of homegrown terrorism that can be generated in the transfer to multi-culture society as various foreigners come to Korea rapidly and suggest the method to cope with the trend. The study analyzed environment and analysis of homegrown terrorism that Korea faces now. The methods to cope with homegrown terrorism are as follows. First, distribution of radical homegrown terrorism via internet should be prevented. Second, the connection between terrorist organization and homegrown terrorist should be prevented. Third, there should be a cooperation among government, residents and religious group. Fourth, there should be an open approach against multi-culture society. Fifth, there should be a systematic control for cause of new conflict. Finally, there should be a long-term approach to cause of new conflict. If we do not make an effort to prevent homegrown terrorism, terrorism environment may face new aspect and national and social cost for it will increase.

• Korean Security Journal
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• no.58
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• pp.59-80
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• 2019

Recently, our company has entered the modern knowledge company, government policy and regulation has a big influence on people's lives. Also, unlike in the past, I am hoping for administrative intervention as a problem peculiar to the environment, such as environmental housing problems, urban transportation problems, misuse problems, etc. and corporate pending issues. In this study, through the 10th year of the Seoul Special Citizen Judicial Police Force, if the local autonomy is a special envoy, it will try to present the correctness in the organization luck. As a measure to secure the nature of administrative action, the method of investigation was through the study of the execution process of administrative penalty and its result based on the statistical data of Seoul City. Therefore, we will analyze the process and operation of the 10-year organizational change of the Seoul Metropolitan Government's police force and examine how the police force of the people's livelihoods, which is a special investigation organization, is expanding its duties in order to strengthen the enforcement power of the administration. Also, we will make future-oriented suggestions to encourage the readjustment of the current relevant laws, such as the Ministry of Patriots and Veterans Affairs, and to actively accommodate the expected changes of the special law police organization in charge of the enforcement of the police system.

• Journal of the Korea Convergence Society
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• v.9 no.9
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• pp.209-215
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• 2018

The purpose of this study is to grasp the overall policy decision system of sex crime prevention policy and analyze the interaction and pattern of actors in policy formation process. This is a useful way to identify the causes and ways to improve the policy if the sex crime prevention policy fails. As a research method, we used a model of advocacy through case analysis and language network analysis. In the external environment, low reporting of sex offenses, technical improvement and supplement for preventive management, consciousness of victims of sexual crimes, amendment of legislation, and support of the president. The conflicts between the advocacy coalition opposed the strong regulation, the prevention of recidivism, the expansion of the range of objects to be worn, the temporary effect of the system and the retrospective of the bill. As a problem-solving strategy, it was confirmed that the opposing positions of pros and cons of lack of manpower and negligence of management through the extension of the system were acutely opposed. In the context of media reports, this tendency is more likely to be understood as the concern of prevention and management at the central government level to prevent sex crimes. Therefore, although the methods of prevention of sex crimes have been insufficient in the past, it is hoped that this study will be helpful in breaking the link of negative policy vicious cycle.

• Journal of the Korea Concrete Institute
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• v.25 no.5
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• pp.497-508
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• 2013

This paper introduces a numerical model which can evaluate the fire-resistant capacity of reinforced concrete members. On the basis of the transient heat transfer considering the heat conduction, convection and radiation, time-dependent temperature distribution across a section is determined. A layered fiber section method is adopted to consider non-linear material properties depending on the temperature and varying with the position of a fiber. Furthermore, effects of non-mechanical strains of each fiber like thermal expansion, transient strain and creep strain are reflected on the non-linear structural analysis to take into account the extreme temperature variation induced by the fire. Analysis results by the numerical model are compared with experimental data from the standard fire tests to validate an exactness of the introduced numerical model. Also, time-dependent changes in the resisting capacities of reinforced concrete members exposed to fire are investigated through the analyses and, the resisting capacities evaluated are compared with those determined by the design code.