• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.377-380
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• 2008

The material and mechanical properties in the high temperature area of 40 to 100 MPa high strength concrete structural member was identified based on mixing of fiber cocktail and the structural element fire behavior simulation through the finite element analysis method (ABAQUS) was interpreted. The results are as follows. First, it was interpreted that the test specimen with concrete fiber cocktail mixed was more controllable in the maximum shrinkage than the one with concrete fiber cocktail not mixed the controllable range was about 25% to 55%. This means that shrinkage is controllable through mixing of fiber cocktail for the high strength concrete columns. Second, this study didn't consider the explosive spalling by the pore pressure within high strength concrete. If the properties for the pore pressure within high strength concrete is considered and database by strength and by inner temperature of various high strength concrete and steel materials are established in the future, it is interpreted that the technical foundation will be laid for performance based design of fire resistant construction.

• Structural Engineering and Mechanics
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• v.74 no.2
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• pp.227-241
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• 2020

The bi-axial and shear buckling behavior of laminated hypar shells having rhombic planforms are studied for various boundary conditions using the present mathematical model. In the present mathematical model, the variation of transverse shear stresses is represented by a second-order function across the thickness and the cross curvature effect in hypar shells is also included via strain relations. The transverse shear stresses free condition at the shell top and bottom surfaces are also satisfied. In this mathematical model having a realistic second-order distribution of transverse shear strains across the thickness of the shell requires unknown parameters only at the reference plane. For generality in the present analysis, nine nodes curved isoparametric element is used. So far, there exists no solution for the bi-axial and shear buckling problem of laminated composite rhombic (skew) hypar shells. As no result is available for the present problem, the present model is compared with suitable published results (experimental, FEM, analytical and 3D elasticity) and then it is extended to analyze bi-axial and shear buckling of laminated composite rhombic hypar shells. A C⁰ finite element (FE) coding in FORTRAN is developed to generate many new results for different boundary conditions, skew angles, lamination schemes, etc. It is seen that the dimensionless buckling load of rhombic hypar increases with an increase in c/a ratio (curvature). Between symmetric and anti-symmetric laminations, the symmetric laminates have a relatively higher value of dimensionless buckling load. The dimensionless buckling load of the hypar shell increases with an increase in skew angle.

• Journal of the Korean Society of Safety
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• v.35 no.5
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• pp.30-38
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• 2020

In order to construct a dam, the diversion facility such as cofferdam and a diversion tunnel should be installed in advance. And size of a cofferdam depends on type of a main dam. According to the Korea Dam Design Standard, if the main dam is a concrete dam, design flood of the cofferdam is 1~2 years flood frequency. This means that overflow of the cofferdam occurs one time for 1 or 2 years, therefore, stability of the cofferdam should be secured against any overflow problem. In this study, failure probability analysis for the concrete cofferdam is performed considering the overflow. First of all, limit state function of the concrete cofferdam is defined for overturning, sliding and base pressure, and upstream water levels are set as El. 501 m, El. 503 m, El. 505 m, El. 507 m. Also, after literature investigation research, probabilistic characteristics of various random variables are determined, the failure probability of the concrete cofferdam is calculated using the Monte Carlo Simulation. As a result of the analysis, when the upstream water level rises, it means overflow, the failure probability increases rapidly. In particular, the failure probability is largest in case of flood loading condition. It is considered that the high upstream water level causes increase of the upstream water pressure and the uplift pressure on the foundation. In addition, among the overturning, the sliding and the base pressure, the overturing is the major cause for the cofferdam failure considering the overflow.

• International Journal of Highway Engineering
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• v.15 no.5
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• pp.65-73
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• 2013

PURPOSES : This study is to suggest future development direction and application of environmental noise barriers as multi-functional soundproof wall. METHODS : Based on the literature review, case study and patent search, research and patent trend were investigated. Patent search was conducted by Patent searching tools, 'Focust'. RESULTS : As environmental noise barriers, Vegetative soundproof wall, photovoltaic soundproof wall, and air-pollution reduction soundproof wall were investigated. First of all, In Korea, Vegetative soundproof wall is being developed mostly as soundproof wall that has vegetation foundation inside, to meet the domestic condition with 23 patent applications. Second, Photovoltaic soundproof wall is being developed mainly with efficiency of photovoltaic system rather than soundproofing. And it is limited to one generation solar cell technology, although Solar cell technology is developing at a rapid pace. On the other hand, for reducing air-pollutant by soundproof wall, a variety of methods are being suggested (filtration, adsorption, and photocatalytic oxidation), and one of them, adsorption are applied for developing air pollution reduction soundproof wall in Korea. CONCLUSIONS: The above soundproof wall is not simple structure, but road facility applied fusion technique. Therefore, as one system, it is difficult to harmonize due to various considerations for design factor. However, if it's possible that a benefits of one system apply to another system, Synergy effect may be created. In the foreseeable future, soundproof wall may be considered as a road system using fusion technique rather than just functional facility. Therefore, substantial studies for applying multi-functional soundproof wall on the road are needed for the future.

• 한국사회정책
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• v.25 no.4
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• pp.301-321
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• 2018

The purpose of this paper is to analyze whether any combination of the quantitative and qualitative aspects of the public pension system is a causal factor for the elderly poverty reduction rate. For this, fuzzy-set qualitative comparison analysis was conducted with the poverty reduction rate as the outcome condition variable, the public pension expenditure ratio, the redistributive index, the first floor public pension weight, the second floor public pension weight and the second floor forced private pension weight did. As a result of the analysis, the combination of high public pension expenditure ratio, low two - tier public pension share and high two - tier compulsory private pension share has become a cause of high poverty reduction rate of the elderly. And more various forms of association were found as the cause of low poverty reduction rate of the elderly. This paper suggests policy proposals based on the above findings.

• The Journal of Korean Medicine
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• v.43 no.4
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• pp.102-130
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• 2022

Objectives: The persistence and unpredictability of coronavirus disease (COVID-19) and new measures to prevent direct medical intervention (e.g., social distancing and quarantine) have induced various psychological symptoms and disorders that require self-treatment approaches and integrative treatment interventions. To address these issues, the Korean Medicine Mental Health (KMMH) center developed a field manual by reviewing previous literature and preexisting manuals. Methods: The working group of the KMMH center conducted a keyword search in PubMed in June 2021 using "COVID-19" and "SARS-CoV-2". Review articles were examined using the following filters: "review," "systematic review," and "meta-analysis." We conducted a narrative review of the retrieved articles and extracted content relevant to previous manuals. We then created a treatment algorithm and recommendations by referring to the results of the review. Results: During the initial assessment, subjective symptom severity was measured using a numerical rating scale, and patients were classified as low- or moderate-high risk. Moderate-high-risk patients should be classified as having either a psychiatric emergency or significant psychiatric condition. The developed manual presents appropriate psychological support for each group based on the following dominant symptoms: tension, anxiety-dominant, anger-dominant, depression-dominant, and somatization. Conclusions: We identified the characteristics of mental health problems during the COVID-19 pandemic and developed a clinical mental health support manual in the field of Korean medicine. When symptoms meet the diagnostic criteria for a mental disorder, doctors of Korean medicine can treat the patients according to the manual for the corresponding disorder.

• Journal of the Korean GEO-environmental Society
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• v.24 no.11
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• pp.41-49
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• 2023

In this study, we analyzed the settlement characteristics of rockfill embankments mixed with soil by confirming the physical properties of soil materials mixed with silty materials and analyzing the compression characteristics of gravel materials according to the mixing ratio of soil materials. For this, we mixed silty materials into sandy soil to analyze the compression characteristics of soil materials, and we constructed a foundation by mixing various ratios of soil into rockfill materials with a particle distribution similar to that of river gravel, and conducted a one-dimensional compression experiment using a medium-sized chamber. As a result of the experiment, in the case of mixed soil materials, the Transition Fine Content (TFC) appeared in the range of 21~26% depending on the load condition, and in the case of rockfill materials mixed with soil, as the void filling ratio of soil in gravel samples increases, both total compression and creep compression decreases, but after a 50% mixing ratio, the settlement of amount increases again.

• Journal of the Korean Geotechnical Society
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• v.36 no.10
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• pp.5-19
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• 2020

With increasing demand for offshore structures, the demand for temporary structures to help the offshore construction work has increased. A cofferdam is a temporary barrier to stop the inflow of water in the construction site and allows working in the dry condition when the construction is done within the water. However, it is a major cause of construction delays and increased costs because additional works are required to block the water inflow. Recently, in order to overcome the limitations of the conventional cofferdam methods and to increase economic efficiency, a large-diameter steel cofferdam method has been proposed which can be installed quickly in the seabed by using the suction pressure. In this circular steel cofferdam method, the top side of the cofferdam including the top-lid is always exposed above the sea level in order to use it as a water barrier, unlike the conventional suction bucket foundation. After installation, the top-lid of the cofferdam is removed and the water filled inside the cofferdam is discharged to make the interior dry condition. In this study, the circular steel cofferdam with a 5 m inner diameter was fabricated and the installation tests were conducted at the Saemaguem test site. During the experiment, variation of suction pressure, leakage between connections, structure deformation, and inclination of the steel cofferdam were measured and post-analyzed. This study verified the new circular steel cofferdam method and confirmed that the suction installation method can be successfully used for various purposes on offshore structures.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5534-5540
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• 2015

This In the railway signaling system, applications of axle counter in addition to track circuit goes on increasing for detecting train position. Consequently, this paper compares sensor methods of axle counter with between geo-magnetism method and proximity sensor method. And it presents differences and results, to improve reliabilities of train detection and axle counting. Also, this article presents an applied result which is based on field experience, with regard to installation, considering attachment condition of sensor part for accurate axle counting. This study acquires expandability that is able to perform not only axle counting function but also various other functions (direction detection of train, speed detection of train, and so on). It was a result of a change of design in order to judge phase difference of sensors, to improve reliability of axle counting. Furthermore, it does not subordinate to characteristics (type, weight of train). And it is confirmed that the omission of axle counting was not occurred in 350km/h. This was the result of Lab test after the construction of transfer equipment of trial axle and Test Bed for axle counting. Both of them are self-productions. Through this, it prepares foundation which is able to apply not only to train detection but also to speed of passing trains, formation number of trains, detector locking condition - when the train passes the section of switch point, and level crossing devices. Furthermore, it would be judged to contribute safety train operation if proximity sensor method applies to the whole railway signaling system from now on.

• Journal of Korean Philosophical Society
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• v.116
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• pp.437-464
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• 2010

The article, focusing on the theory of Zhong-He, sheds a new light on the philosophy of Daizhen. The theory of Zhong-He, according to the philosophical system of Zhuxi, serves as the theoretical foundation in erecting the apriori moral nature and guiding mental cultivation of subjects. Daizhen, on the contrary, criticizes the doctrine of Zhonghe in Zhuxi's philosophy as it produces negative side-effects of moral dogmatism. Zhuxi's doctrine, according to Daizhen, as it reduce the origin of morality to apriori condition of consciousness and delimit the range of cultivation to psychological realm of subjects, restricts moral subjects in the fortress of their own subjectivity. In this vein of his criticism, Daizhen attempts new interpretation on Zhonghe. The character Zhong (中), according to him, does not refer to apriori moral state or metaphysical moral substance as it does in the doctrine of Zhuxi. On the contrary, it denotes the state in which diverse existent beings are placed in their own position by their own dispositions. Similarly, the other character He (和) does not refer to the condition where an individual's consciousness is in equilibrium, but to the process of achieving the harmony of entire society in which diverse existent beings are communicating to each other. With his novel interpretation of the theory of Zhong-He, Daizhen could dissolve the tradition of Weifa (未發) and moral subjectivism in Zhuxi's philosophy and provide a way of establishing reciprocal communication and harmony between various individuals. It is in his ethics of rational mutual understanding where the significance of Daizhen's philosophy should be found.