• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.1
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• pp.62-68
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• 2001

In order to characterize the microscopic fracture behaviour of the weldment din stress corrosion cracking(SCC) phenomena, SCC and acoustic emission(AE) tests were carried out simultaneously and the correlation between mechanical paramenters obtained from SCC and AE tests was investigated. In the case of base metal, much more AE events were produced at -0.5V than at -0.8V because of the dissolution mechanism before the maximum load. Regardless of the applied voltages to the specimens, however, AE events decreased after the maximum load. In the case of weldment, lots of AE events with larger amplitude $range(40{\sim}100dB)$ were produced because of the singularities of weld HAZ in comparision to the base metal and post-weld heat-treated(PWHT) specimens. Numerous and larger cracks for the weldment were observed on the fractured surfaces by SEM examination. From these results, it was concluded that SCC for the weldment appeared most severely in synthetic seawater. Weld HAZ was softened by PWHT which also contributed to the reduced susceptibility to corrosive environment in comparison to the weldment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4635-4642
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• 2010

Latex modification of concrete provides the material with higher flexural strength, as well as high bond strength and reduced water permeability. One of the most advantages of the very early-strength latex-modified concrete (VES-LMC) could be the similar contraction and expansion behaviour to normal concrete substrate, which enable to ensure long-term performance. The purpose of this study was to parametric nonlinear flexural nonlinear analysis of RC beam rehabilitated by VES-LMC. The results were as follows; The flexural nonlinear analysis model of RC beam overlaid by VES-LMC in ABAQUS was proposed to predict the load-deflection response, interfacial stress, and ultimate strength. The proposed FE analysis model was verified by comparison of an experimental data and the FE analysis results. The FE analysis results showed that yield point as well as flexural stiffness increased as the depth increased; the stiffness of beam overall increased as the bond stiffness became larger; the bond strength between two different materials is a key factor in composite beam. A parametric study showed that an overlay thickness was a main influencing factor to the behavior of RC beam overlaid by VES-LMC.

• Nutrition Research and Practice
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• v.10 no.1
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• pp.56-66
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• 2016

BACKGROUND/OBJECTIVES: Despite successes recorded in combating iodine deficiency, more than 2 billion people are still at risk of iodine deficiency disorders. Rural landlocked and mountainous areas of developing countries are the hardest hit, hence the need to explore and advance novel strategies such as biofortification. SUBJECTS/METHODS: We evaluated adoption, purchase, and consumption of iodine biofortified vegetable legumes (IBVL) using the theory of protection motivations (PMT) integrated with an economic valuation technique. A total of 1,200 participants from three land-locked locations in East Africa were recruited via multi-stage cluster sampling, and data were collected using two, slightly distinct, questionnaires incorporating PMT constructs. The survey also elicited preferences for iodine biofortified foods when offered at a premium or discount. Determinants of protection motivations and preferences for iodine biofortified foods were assessed using path analysis modelling and two-limit Tobit regression, respectively. RESULTS: Knowledge of iodine, iodine-health link, salt iodization, and biofortification was very low, albeit lower at the household level. Iodine and biofortification were not recognized as nutrient and novel approaches, respectively. On the other hand, severity, fear, occupation, knowledge, iodine status, household composition, and self-efficacy predicted the intention to consume biofortified foods at the household level; only vulnerability, self-efficacy, and location were the most crucial elements at the school level. In addition, results demonstrated a positive willingness-to-pay a premium or acceptance of a lesser discount for biofortification. Furthermore, preference towards iodine biofortified foods was a function of protection motivations, severity, vulnerability, fear, response efficacy, response cost, knowledge, iodine status, gender, age. and household head. CONCLUSIONS: Results lend support for prevention of iodine deficiency in unprotected populations through biofortification; however 'threat' appraisal and socio-economic predictors are decisive in designing nutrition interventions and stimulating uptake of biofortification. In principle, the contribution is threefold: 1) Successful application of the integrated model to guide policy formulation; 2) Offer guidance to stakeholders to identify and tap niche markets; 3) stimulation of rural economic growth around school feeding programmes.

• Resources Recycling
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• v.17 no.1
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• pp.51-58
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• 2008

Artificial mattes were prepared with adding pyrite or chalcopyrite as sulfur sources with Cu-Ni-Co-Fe alloy. The major phases identified by X-ray diffraction pattern were $(FeSi)_9S_8$, $CuFeS_2$, FeS, $Co_4S_3$, $Ni_3S_2$ and $Cu_2S$ for both mattes, and the matte prepared by adding chalcopyrite showed the higher peak of $Cu_2S$ due to high content of copper. Under optimum conditions, more than 95% copper, 90% nickel and 90% cobalt were extracted into leaching solution and sulfur concentration in the mattes did not much affect the leaching efficiency of the metals. The increase of the amount of pyrite or chalcopyrite added decreased pH in leaching solution and increased the concentration of iron ion dissolved in the leaching solution and the amount of residue.

• (The) Research of the performance art and culture
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• no.33
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• pp.223-242
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• 2016

The Korean $taeg{\breve{u}}m$, a horizontal bamboo flute, is considered a representative wind instrument of Korean traditional music. Symbolized by its unique timbre and diverse techniques, this instrument transmits the beauty of Korea, and has become acknowledged even in international music scenes. Being a $taeg{\breve{u}}m$ player, composer, and ethnomusicology researcher, I have developed creative collaborations with musicians from Asian, electro-acoustic, jazz, and Western art music traditions developed outside my country of origin and tried to overcome musical boundaries through the 'intercultural performances' (after Turner 1988). Zooming in one collaboration, I detail the process of music creation and performance, collaborating with prominent Korean composer Kim $Taes{\breve{o}}ng$ (b.1967), who was commissioned by myself to write two compositions for the $taeg{\breve{u}}m$ and Western art music. The purpose is twofold: firstly, the modernization and appropriation of the Korean flute is briefly tracked down within the context of Western Art music. Secondly, a performance project is illustrated with the support of technical apparatuses such as DVD and CD recordings and delves further into the question of the 'cultural relativism' (Michael Tenzer, 2006: 7) through the interactive process. The performance-as-research, as a tool 'actualizing' (Richard Schechner 2003: 32) the hybridity, touches on critical domains in Ethnomusicology. The corresponding two parts discover, as Alan Merriam's(1964) 'tripartite model' suggests, the 'context' of Korean and Western cultures, the 'behaviour' of collaborating and performing and the 'sound' of improvised and composed productions in the course of music making.

• Journal of Korean Philosophical Society
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• v.131
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• pp.131-163
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• 2014

This Paper aims to elaborate on the origin of thinking mind. And this is a cooperative project between philosophy and neuroscience and brain science. I have written this paper in admiration for the achievements of twentieth century neuroscience and brain science, and out of desire to assist the subject in future. Much of the history of modern philosophy, from Descartes and Kant forward, consists of failed models of brain. As Edward O. Wilson precisely said, the shortcoming is not the fault of the philosophers, who have doggedly pushed their methods to the limit, but a straightforward consequence of the biological evolution of the brain. Guiding that investigation down pathways that will illuminate brain research is a task of neuroscience and brain science. Investigating logical relations among concepts is a philosophical task. If we are to understand the neural structures and dynamics that make perception, thought, intentional behaviour possible, clarity about these concepts and categories and their relations is essential. Hence our joint venture of philosophy and science. Sure, it is human beings that perceives, not parts of its brain. And it is human beings that who think and reason, not their brain. But the brain and its activities make it possible for human beings-not for it-to perceive and think, to feel emotions, and to form and pursue projects. Thus We try to investigate and reveal the origin of thinking mind as follow: 1) The difference between chimpanzee and human beings 2) brain and mind 3) the origin of thinking 4) the wisdom of nature.

• The Journal of the Korea Contents Association
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• v.19 no.10
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• pp.165-178
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• 2019

Start-up companies have recently emerged as an important pillar of the national economy, becoming the core of expanding new growth engines and creating jobs for the national economy. Accordingly, this study used the Start-up Behavior (opportunity discovery, opportunity utilization) as the main variable to verify the parameter effects, and empirically analyzed the factors of the start-up characteristics on the management performance of the start-up company. To achieve this goal, 221 technology-intensive start-ups 2 to 7 years old were surveyed and analyzed for 22 days from March 4 to March 25, 2019. In summary, the results of the study are as follows. First, it has been shown that "starting-up characteristics" have a positive influence on "start-up behavior." Second, it has been shown that "creative behavior" has a positive influence on "management performance." Third, the effect of "starting-up characteristics" on "start-up behaviour" was shown to be different according to "population statistical characteristics (gender, educational background). Fourth, the effect of "starting up action" on "management performance" was shown to be different according to the demographic characteristics (gender, educational background). Finally, "Start-up Action" has been shown to have a mediated effect in the relationship between "Start-up Characteristics" and "management performance."

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.3
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• pp.271-278
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• 2019

The corrosion of reinforcements embedded in concrete causes severe deterioration in reinforced concrete structures. As a countermeasure, epoxy coated reinforcements are used to prevent corrosion of reinforcements. When epoxy coated bars are used, the resistance of corrosion is excellent, but epoxy coating on the bars have a disadvantage of reduction in bond capacity comparing to that of normal bars. Therefore, it is necessary to confirm the bond performance of epoxy coated reinforcements through experimental and analytical methods. Bond behaviors of epoxy coated bars for various diameters of 13 and 19mm and thicknesses of cover concrete of 3 types(ratio of cover to bar diameter) are examined. As the diameters of the epoxy coated bars increase, the difference of bond strength between epoxy coated and uncoated bars also increases and damage patterns showed pull out failure. In addition, finite element analysis was performed based on the bond-slip relationship obtained by direct pullout test and compared with the flexural test results. It is considered that flexural member test is more useful than pullout test for simulating the behavior of actual structure.

• Structural Engineering and Mechanics
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• v.50 no.5
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• pp.589-603
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• 2014

Expressions for determining the value of the impact force as reported in the literature and incorporated into code provisions are essentially quasi-static forces for emulating deflection. Quasi-static forces are not to be confused with contact force which is generated in the vicinity of the point of contact between the impactor and target, and contact force is responsible for damage featuring perforation and denting. The distinction between the two types of forces in the context of impact actions is not widely understood and few guidelines have been developed for their estimation. The value of the contact force can be many times higher than that of the quasi-static force and lasts for a matter of a few milli-seconds whereas the deflection of the target can evolve over a much longer time span. The stiffer the impactor the shorter the period of time to deliver the impulsive action onto the target and consequently the higher the peak value of the contact force. This phenomenon is not taken into account by any contemporary codified method of modelling impact actions which are mostly based on the considerations of momentum and energy principles. Computer software such as LS-DYNA has the capability of predicting contact force but the dynamic stiffness parameters of the impactor material which is required for input into the program has not been documented for debris materials. The alternative, direct, approach for an accurate evaluation of the damage potential of an impact scenario is by physical experimentation. However, it can be difficult to extrapolate observations from laboratory testings to behaviour in real scenarios when the underlying principles have not been established. Contact force is also difficult to measure. Thus, the amount of useful information that can be retrieved from isolated impact experiments to guide design and to quantify risk is very limited. In this paper, practical methods for estimating the amount of contact force that can be generated by the impact of a fallen debris object are introduced along with the governing principles. An experimental-calibration procedure forming part of the assessment procedure has also been verified.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.2
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• pp.87-92
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• 2011

This paper describes a study on the permeability reduction of the riverbed ground during urban railway tunnel construction. The research is mainly concentrated on the study of the grouting or injection methods among permeability reduction methods which can be adapted in the riverbed ground. The design technology of grouting methods considering the long term hydro-geological behaviour in the riverbed, was suggested. Two injection methods namely, Natural Durable Stabilizer (N.D.S) and Space-Multi Injection Grouting (S.M.I) methods, were introduced as new approach methods which could be adapted to modify the riverbed ground. In order to evaluate the performance of the improved ground by the N.D.S and S.M.I method, a series of pilot tests including the field and laboratory permeability tests, were carried out in the river crossing tunnel construction sites. The results obtained from pilot test program, were also reviewed. The results, the grouting efficiency of the S.M.I method using the non-alkalimeter silica sol is better than that of N.D.S method using cement. In addition, it is anticipated that the current research results are contributed to develop the grouting design technology.