• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.14-17
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• 2004

A prefabricated composite hollow slab with perforated I-beams was suggested for the replacement of deteriorated concrete decks or the construction of new composite bridges with long-span slabs. Composite slabs with embedded I-beams have considerably higher stiffness and strength. For the application of prefabricated composite slabs to bridges, joints between slabs should satisfy the requirements of the ultimate limit state and the serviceability limit state. In this paper, three types of the detail for loop joints were selected and their structural performance in terms of strength and crack control was investigated through static tests on continuous composite slabs. A main parameter was the detail of the joint, such as an ordinary loop joint and loop joint with additional reinforcements. Even though there was no connection of the steel beams at the joints, the loop joints showed good performance in ultimate strength. In terms of crack control, the loop joint with additional reinforcements showed better performance. In ultimate limit state, the continuous composite slabs showed good moment redistribution and ductility.

• The Journal of Asian Finance, Economics and Business
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• v.6 no.4
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• pp.129-137
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• 2019

Tax can be categorised into direct tax and indirect tax. This paper uses the ordinary least-squares regression method to study the impact of direct and indirect tax on economic growth in Vietnam in the period 2003-2017. Statistical data is collected from the Ministry of Finance of Vietnam. Theoretically, tax generates the state budget revenue and is a tool to regulate the economy. The results of statistical tests show that tax has a positive impact on Vietnam's economic growth. However, the effects of direct tax and indirect tax are different. The indirect tax has a positive influence and promote Vietnam's economic growth, while the impact of the direct tax is invisible. There has not been sufficient evidence to confirm that the indirect tax has a more positive impact than the direct tax. To promote economic growth, Vietnam needs to restructure its tax system towards: (1) Increasing the proportion of indirect tax, reducing the proportion of direct tax in the state budget revenue; (2) Expanding tax bases; (3) Reducing tax rates of corporate income tax and personal income tax; (4) Increasing tax rates of environmental protection tax, natural resources tax, value added tax and excise tax on some types of goods which harm health and environment.

• Korean Security Journal
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• no.8
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• pp.1-26
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• 2004

The current consitutional law 29-1 is ordaining the State Tort Liability for the illegal action of public service personnel. Based on this regulation, the State Tort Liability Act 2-1 actualizes by indicating, the nation or the local self-governing community is responsible for the public service personnels damaging others during their office hours whether it is accidental or intentional. However, the same law is considered to be inappropriate for the damage relief. In order to supplement this problem, through examinations at both theoretical and systematic levels of Prima facie as well as the objectification and standardization of the damages are required for the national compensation for the police action. According to the objectification and standardization of the damage theory, the faulty actions of the public service personnel are the defects occurred during the office hours. In the case of the police action that frequently uses infringement administration, invading the liberty and rights of the people, it is necessary to interpret faulty damages during the office duties more comprehensively so as to extend its scope of the ordinary public service personnel accidental illegality. In order to warrant effectiveness of the securing the rights, it is crucial to distinguish whether the faulty actions are accidental or intentional. When proven to be damages by illegal police action, the police personnel is responsible for the faults, called Prima facie, the nation is liable for the damage relief.

• Journal of Microbiology and Biotechnology
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• v.5 no.4
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• pp.181-187
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• 1995

The cells of Vibrio vulnificus can be induced to the viable but nonculturable (VBNC) state by natural environmental parameters. The V. vulnificus cells in the VBNC state can not be recovered by ordinary laboratory techniques. This nonculturability could often hamper development of effective processing strategies to minimize the number of V. vulnificus in seafoods. Even with V. vulnificus cells in a culturable state, the length of time required to identify the bacteria in contaminated food by phenotyphic characterization may prevent appropriate in-time responses by public health agencies to infections of the bacteria. In the present study, we used polymerase chain reaction (PCR) to develop a rapid and direct detection method for V. vulnificus in small octopus (Octopus variabilis) which is consumed as a raw food in Korea. The region targeted was a 704-base pair (bp) portion of the hemolysin gene, vvhA, of V. vulnificus. The primers designed for PCR amplification were specific for all V. vulnificus sp. tested. Several methods were examined to extract total DNA directly from V. vulnificus seeded into the octopus homogenate and the guanidine isothiocyanate (CITC) method appeared to be most effective. From the octopus homogenate seeded by V. vulnificus at an initial level of $10^2$ CFU/ml of the homogenate and then incubated for 12 h, the targeted sequence was successfully amplified by PCR and the 704-bp DNA fragment was observed by gel electrophoresis. The total completion of this assay requires less than one day.

• Hwankyungkyoyuk
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• v.11 no.1
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• pp.217-236
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• 1998

There is lack of social awareness on the importance of natural environments and effective operating systems for environmental education in natural settings. In this study, the environmental education systems of three U. S. National Parks in the State of Washington were investigated in order to examine the potential of applying the environmental education systems to the Korean situation. To this end, the authors made field trips to the Mount Rainier National Park, Olympic National Park and North Cascades National Park and interviewed the field environmental education professionals. There is one common theme of environmental education shared by the three National Parks, that is the National Parks are open to the students and ordinary people as classrooms for environmental education. All of the three National Parks were supported by regional societies of environmental conservation and education. However, the contents of the approaches to the environmental education of each National Park were different to each reflecting the differences of the natural environment and cultural background. This implies that environmental education systems should be designed based on the characteristics of the local environment and cultural tradition, although advanced environmental education systems of foreign countries would be useful for developing our own environmental education systems.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.850-860
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• 2023

An industrial control process multiple-input multiple-output (MIMO) coupled system is analyzed in this study as an example of a Loss of Coolant Accident (LOCA) simulation system. Ordinary control algorithms can complete the steady state of the control system and even reduce the response time to some extent, but the entire system still consumes a large amount of energy after reaching the steady state. So a multivariable decoupled energy-saving control method is proposed, and a novel energy-saving function (economic function, Eco-Function) is specially designed based on the active disturbance rejection control algorithm. Simulations and LOCA simulation system tests show that the Eco-function algorithm can cope with the uncertainty of the multivariable system's internal parameters and external disturbances, and it can save up to 67% of energy consumption in maintaining the parameter steady state.

• International Journal of Concrete Structures and Materials
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• v.8 no.4
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• pp.289-299
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• 2014

Alkali-activated slag concretes are being extensively researched because of its potential sustainability-related benefits. For such concretes to be implemented in large scale concrete applications such as infrastructural and building elements, it is essential to understand its early and long-term performance characteristics vis-a'-vis conventional ordinary portland cement (OPC) based concretes. This paper presents a comprehensive study of the property and performance features including early-age isothermal calorimetric response, compressive strength development with time, microstructural features such as the pore volume and representative pore size, and accelerated chloride transport resistance of OPC and alkali-activated binder systems. Slag mixtures activated using sodium silicate solution ($SiO_2$-to-$Na_2O$ ratio or $M_s$ of 1-2) to provide a total alkalinity of 0.05 ($Na_2O$-to-binder ratio) are compared with OPC mixtures with and without partial cement replacement with Class F fly ash (20 % by mass) or silica fume (6 % by mass). Major similarities are noted between these binder systems for: (1) calorimetric response with respect to the presence of features even though the locations and peaks vary based on $M_s$, (2) compressive strength and its development, (3) total porosity and pore size, and (4) rapid chloride permeability and non-steady state migration coefficients. Moreover, electrical impedance based circuit models are used to bring out the microstructural features (resistance of the connected pores, and capacitances of the solid phase and pore-solid interface) that are similar in conventional OPC and alkali-activated slag concretes. This study thus demonstrates that performance-equivalent alkali-activated slag systems that are more sustainable from energy and environmental standpoints can be proportioned.

• Structural Engineering and Mechanics
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• v.81 no.2
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• pp.179-194
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• 2022

The bending, buckling and free vibration responses of functionally graded material (FGM) beams are investigated semi-analytically by the scaled boundary finite element method (SBFEM) in this paper. In the concepts of the SBFEM, the dimension of computational domain can be reduced by one, therefore only the axial dimension of the beam is discretized using the higher order spectral element, which reduces the amount of calculation and greatly improves the calculation efficiency. The governing equation of FGM beams is derived in detail by the means of the principle of virtual work. Compared with the higher-order beam theory, fewer parameters and simpler control equations are used. And the governing equation is transformed into a first-order ordinary differential equation by introducing intermediate variables. Analytical solutions of the governing equation can be obtained by pade series expansion in the direction of thickness. Numerical example are compared with the numerical solutions provided by the previous researchers to verify the accuracy and applicability of the proposed method. The results show that the proposed formulations can quickly converge to the reference solutions by increasing the order of higher order spectral elements, and high accuracy can be achieved by using a small number of the elements. In addition, the influence of the structural sizes, material properties and boundary conditions on the mechanical behaviors of FG beams subjected to different load types is discussed.

• Geomechanics and Engineering
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• v.12 no.5
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• pp.831-847
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• 2017

Conventional geotechnical engineering soil binders such as ordinary cement or lime have environmental issues in terms of sustainable development. Thus, environmentally friendly materials have attracted considerable interest in modern geotechnical engineering. Microbial biopolymers are being actively developed in order to improve geotechnical engineering properties such as aggregate stability, strength, and hydraulic conductivity of various soil types. This study evaluates the geotechnical engineering shear behavior of sand treated with xanthan gum biopolymer through laboratory direct shear testing. Xanthan gum-sand mixtures with various xanthan gum content (percent to the mass of sand) and gel phases (initial, dried, and re-submerged) were considered. Xanthan gum content of 1.0% sufficiently improves the inter-particle cohesion of cohesionless sands 3.8 times and more (up to 14 times for dried state) than in the untreated (natural) condition, regardless of the xanthan gum gel condition. In general, the strength of xanthan gum-treated sand shows dependency with the rheology and phase of xanthan gum gels in inter-granular pores, which decreases in order as dried (biofilm state), initial (uniform hydrogel), and re-submerged (swollen hydrogel after drying) states. As xanthan gum hydrogels are pseudo-plastic, both inter-particle friction angle and cohesion of xanthan gum-treated sand decrease with water adsorbed swelling at large strain levels. However, for 2% xanthan gum-treated sands, the re-submerged state shows a higher strength than the initial state due to the gradual and non-uniform swelling behavior of highly concentrated biofilms.

• The Research Journal of the Costume Culture
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• v.16 no.1
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• pp.58-69
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• 2008

The purpose of this research therefore, was to conduct research on the actual state of manufacturers of cycle wears and the condition in wearing; to present the basic data to develop cycle wears which can lessen the trouble for the human body and an excellent feeling in wearing. For research on the actual state of manufacturers of cycle wears, three domestic companies were grasped. To inquire the condition in wearing, the method of questionnaire was used for 100 peoples consisted of male cycling professional players and ordinary peoples with the same tastes. As the result of research: The manufacturers were targeting for the professional players and men with the same tastes. They produced goods by themselves as well as in the form of subcontract, and they did not classify goods for male & female. Materials they used for cycle wears were mainly composed of jersey with spandex and nylon. The production ratio of cycle wears is shown as 80% for company A, 25% for company B, and 90% for company C. They make a pattern of cycle wears by a technical tie-up with foreign companies, or by the development of their own pattern. As the result of study on the present condition in wearing cycle wears according to each season, it was figured out that the users usually weard short-sleeved T-shirts with dividing zipper for summer upper garment, shorts most preferably for summer lower garment; long-sleeved shirts for spring and fall upper garment, and shorts with incision most preferably for spring and fall lower garment. Also, they usually weard jumpers with incision for winter upper garment, and long pants in which ankle parts of incision were tightened most preferably for winter lower garment.