• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.277-280
• /
• 2008

In this paper behavior of U-Channel Bridge (UCB) was studied, and a new analysis model was proposed. Most of the time, permanent and traffic load actions are directly transmitted to main beams located under the carriageway, one of the most distinctive features of UCB is that the edge beams that support the bridge are above the deck, in contrast with a conventional overpass system. In This study models used with the frame elements, the frame and plate elements, and the solid elements were constructed. Assuming that the results of solid models were similar to the real behavior of UCB, results of another models was compared. The results of the models used with the frame and plate elements were similar to the results of solid models, the model used with the frame and plate elements was proposed as an analysis model.

• Korean Chemical Engineering Research
• /
• v.50 no.3
• /
• pp.562-566
• /
• 2012

A novel design of tubular segmented-in-series(SIS) solid oxide fuel cell (SOFC) sub module was presented in this paper. The tubular ceramic support was fabricated by the extrusion technique. The NiO-YSZ anode and the yttria-stabilized zirconia (YSZ) electrolyte were deposited onto the ceramic support by dip coating method. After sintering at $1350^{\circ}C$ for 5 h, a dense and crack-free YSZ film was successfully fabricated. Also, the multi-layered cathode composed of LSM-YSZ composite, LSM and LSCF were coated onto the sintered ceramic support by dip coating method and sintered at $1150^{\circ}C$. The performance of the tubular SIS SOFC cell and sub module electrically connected by the Ag-glass interconnect was measured and analysed with different fuel flow and operating temperature.

• Journal of Korea Water Resources Association
• /
• v.54 no.2
• /
• pp.121-133
• /
• 2021

Suspended Solids (SS) generated in rivers are mainly introduced from non-point pollutants or appear naturally in the water body, and are an important water quality factor that may cause long-term water pollution by being deposited. However, the conventional method of measuring the concentration of suspended solids is labor-intensive, and it is difficult to obtain a vast amount of data via point measurement. Therefore, in this study, a model for measuring the concentration of suspended solids based on remote sensing in the Nakdong River was developed using Sentinel-2 data that provides high-resolution multi-spectral satellite images. The proposed model considers the spectral bands and band ratios of various wavelength bands using a machine learning model, Support Vector Regression (SVR), to overcome the limitation of the existing remote sensing-based regression equations. The optimal combination of variables was derived using the Recursive Feature Elimination (RFE) and weight coefficients for each variable of SVR. The results show that the 705nm band belonging to the red-edge wavelength band was estimated as the most important spectral band, and the proposed SVR model produced the most accurate measurement compared with the previous regression equations. By using the RFE, the SVR model developed in this study reduces the variable dependence compared to the existing regression equations based on the single spectral band or band ratio and provides more accurate prediction of spatial distribution of suspended solids concentration.

• Korean Journal of Computational Design and Engineering
• /
• v.17 no.2
• /
• pp.123-131
• /
• 2012

The requirements for computational resources to perform the structural analysis are increasing rapidly. The size of the current analysis problems that are required from practical industry is typically large-scale with more than millions degrees of freedom (DOFs). These large-scale analysis problems result in the requirements of high-performance analysis codes as well as hardware systems such as supercomputer systems or cluster systems. In this paper, the pre- and post-processing system for supercomputing based large-scale structural analysis is presented. The proposed system has 3-tier architecture and three main components; geometry viewer, pre-/post-processor and supercomputing manager. To analyze large-scale problems, the ADVENTURE solid solver was adopted as a general-purpose finite element solver and the supercomputer named 'tachyon' was adopted as a parallel computational platform. The problem solving performance and scalability of this structural analysis system is demonstrated by illustrative examples with different sizes of degrees of freedom.

• Membrane and Water Treatment
• /
• v.9 no.6
• /
• pp.447-454
• /
• 2018

Although flotation techniques are often used for the removal of algal particles, the practicality of algae-harvesting technologies is limited owing to the complex and expensive facilities and equipment required for chemical coagulation. Here, we examined the feasibility of an approach to separating algal particles from water bodies without the need for chemical coagulants, depending on the condition of the algae, and to determine the optimal conditions. Using Anabaena sp., a cyanobacterium causes algal blooms in lakes, we stimulated auto-flocculation in algal particles without coagulants and conducted solid-liquid separation experiments of algal particles under various conditions. The six cultivation columns included in our analysis comprised four factors: Water temperature, light intensity, nutrients, and carbon source; auto-flocculation was induced under all treatments, with the exception of the treatment involving no limits to all factors, and algal particles were well-settled under all conditions for which auto-flocculation occurred. Meanwhile, flotation removal of auto-flocculated algal particles was attained only when nutrients were blocked after algae were grown in an optimal medium. However, no significant differences were detected between the functional groups of the extracellular polymeric substances (EPSs) of floated and settled algal particles in the FT-IR peak, which can cause attachment by collision with micro-bubbles.

• Korean Journal of Human Ecology
• /
• v.13 no.5
• /
• pp.701-709
• /
• 2004

A cultural model can change as times go by within one ethnic group. For example, a strong familism has existed for a long time throughout a history of Korea, but it is, just like most social values, now in the midst of a rapid change. Accordingly, Koreans' belief about family values and responsibility for supporting their old parents are changing, too. Especially, supporting parents was one of the highly-estimated traditional values, but it seems to no longer exist. However, one's own rearing experience might be a moderator of association of his or her familism with the ebbing value. Therefore, we aim to address the following research question: What is the relations among college student's familism, their own rearing experiences, and their beliefs about supporting old parents. A total of 155 college students participated in this study. Data were analyzed by SPSS. T-test and ANOVA were used for data analysis. The findings are that college students' beliefs in supporting parents are significantly influenced by their familism and rearing experiences: Those with a strong familism and warm rearing experience have solid beliefs in supporting parents.

• Smart Structures and Systems
• /
• v.13 no.1
• /
• pp.1-24
• /
• 2014

The present study deals with two dimensional electro-elastic analysis of a functionally graded piezoelectric (FGP) cylinder under internal pressure. Energy method and first order shear deformation theory (FSDT) are employed for this purpose. All mechanical and electrical properties except Poisson ratio are considered as a power function along the radial direction. The cylinder is subjected to uniform internal pressure. By supposing two dimensional displacement and electric potential fields along the radial and axial direction, the governing differential equations can be derived in terms of unknown electrical and mechanical functions. Homogeneous solution can be obtained by imposing the appropriate mechanical and electrical boundary conditions. This proposed solution has capability to solve the cylinder structure with arbitrary boundary conditions. The previous solutions have been proposed for the problem with simple boundary conditions (simply supported cylinder) by using the routine functions such as trigonometric functions. The axial distribution of the axial displacement, radial displacement and electric potential of the cylinder can be presented as the important results of this paper for various non homogeneous indexes. This paper evaluates the effect of a local support on the distribution of mechanical and electrical components. This investigation indicates that a support has important influence on the distribution of mechanical and electrical components rather than a cylinder with ignoring the effect of the supports. Obtained results using present method at regions that are adequate far from two ends of the cylinder can be compared with previous results (plane elasticity and one dimensional first order shear deformation theories).

• Korean Journal of Computational Design and Engineering
• /
• v.11 no.3
• /
• pp.183-196
• /
• 2006

A new operation strategy. which can guarantee the data consistency of engineering information among the various intelligent information systems, is presented for engineering information of bridges, and construction methodology of integrated database is developed to support the strategy. The two core standard techniques are adopted to construct the integrated database. One is the Standard for the Exchange of Product Model Data (STEP) for CAD/CAE information and the other is the Extensible Markup Language(XML) for engineering document information. The former enabler structural engineers to handle the structural details with three-dimensional geometry-based information of bridges, and ACIS solid modeling kernel is employed to develop AutoCAD based application modules. The latter can make document files into data type for web-based application modules which assist end-users to search and retrieve engineering document data. In addition, relaying algorithm is developed to integrate the two different information, e.g. CAD/CAE information and engineering document information. The pilot application modules are also developed, and a case study subjected to the Han-Nam bridge is presented at the end of the paper to illustrate the use of the developed application modules.

• Korean Journal of Materials Research
• /
• v.13 no.10
• /
• pp.651-657
• /
• 2003

Ultrasonic microscope has been used to detect the defects on surface or inner solid. Conventionally, it has used at a single operating frequency. The resolution and quality of the measured images are determined by a characteristic of the transducer of the ultrasonic microscope. The conventional ultrasonic microscope has been used envelope detector to detect the amplitude of reflected signal, but the changes in amplitude is not sensitive enough for specimen with microstructure that in phase. In this paper, we have studied multi-frequency depth resolution enhancement with ultrasonic reflection microscope for the reflectors of a stainless steel reference specimen and a reference calibration block to be used as the material in nuclear power plants for ISI, PSI. Increased depth resolution can be obtained by taking two, three-dimensional images at more that one frequency and numerically combining the results. As results of the experiment, we could get enhanced images with the rate of contrast in proportion and high quality signal distribution for the image to the changing rate of depth for the reflectors of the two kinds of specimens.

• The Journal of Industrial Distribution & Business
• /
• v.14 no.11
• /
• pp.27-35
• /
• 2023

Purpose: China's economy has changed considerably in recent decades. By delivering a comprehensive knowledge of the elements that support successful foreign direct investment (FDI) in China and practical insights for multinational firms operating in this dynamic environment, this research offers a new perspective and sets itself apart from previous studies. Research design, data and methodology: It is necessary to give a thorough overview of the body of information on successful FDI in China, which justifies the adoption of a systematic literature review. The study may use a wide range of studies because of this methodology, which guarantees that inferences have a solid and supported basis in data. Results: The findings in the present study have clarified how China's government policies and regulatory framework affect foreign direct investment (FDI). Previous studies have indicated that regulatory changes can significantly impact FDI. For instance, more foreign direct investment (FDI) has been drawn to liberalized industries such as technology and finance. Conclusions: In conclusion, for foreign direct investment (FDI) to be successful in China, it is essential to consider these four factors: local partnerships and cultural adaptation, market research and entry strategy, regulatory environment and policy support, and risk management and contingency planning.