• Magazine of the Korean Society of Agricultural Engineers
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• v.22 no.2
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• pp.83-100
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• 1980

This study was intended to computerize the structural analysis of two-dimensional continuum by finite element method, and to provide a preparatory basis for more sophisticated and more generalized computer programs of this kind. A computer program, applicable to any shape of two-dimensional continuum, was formulated on the basis of 16-degree-of- freedom rectangular element. Various computational aspects pertaining to the implementation of finite element method were reviewed and settled in the course of programming. The validity of the program was checked through several case studies. To assess the accuracy and the convergence characteristics of the method, the results computed by the program were compared with solutions by other methods, namely the analytical Navier's method and the framework method. Through actual programming and analysis of the computed results, the following facts were recognized; 1) The stiffness matrix should necessarily be assembled in a condensed form in order to make it possible to discretize the continuum into practically adequate number of elements without using back-up storage. 2) For minimization of solution time, in-core solution of the equilibrium equation is essential. LDLT decomposition is recommended for stiffness matrices condensed by the compacted column storage scheme. 3) As for rectangular plates, the finite element method shows better performances both in the accuracy and in the rate of convergence than the framework method. As the number of elements increases, the error of the finite element method approaches around 1%. 4) Regardless of the structural shape, there is a uniform tendency in convergence characteristics dependent on the shape of element. Square elements show the best performance. 5) The accuracy of computation is independent of the interpolation function selected.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.275-275
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• 2013

Formation and characterization of self-assembled monolayers (SAMs) on various surfaces are the essential basis for many other applications, including molecular switches, biosensors, microfluidics, and fundamental studies in surfaces and interfaces. To improve the performance at these applications, it is a key to control the quantity of each molecule in various mixed SAMs on the surface. In this study, using mixed SAM of carbamate-based hydroquinone (HQ)-PhBr and11-mercaptoundecanol, the quantitative mass spectrometric method of mixed SAM was developed based on comparison study with XPS and FT-IR methods. In addition, our method was applied to another mixed SAM of biotinylated PEG alkane thiol and 11-mercaptoundecanol for verification purpose. Time-of-flight secondary mass spectrometry (ToF-SIMS) analysis was performed to identify and quantify each molecule of mixed SAM along with principal component analysis (PCA). Since there is no matrix effect in the X-ray photoelectron spectroscopy (XPS) and Fourier transform-infrared (FT-IR) techniques, we compared ToF-SIMS results with XPS and FT-IR results. Because PCA results from ToF-SIMS analysis are well matched with XPS and FT-IR results from both mixed SAMs, we are expecting that our method will be useful to identify and quantify each molecule in various mixed SAMs.

• The Research Journal of the Costume Culture
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• v.27 no.6
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• pp.645-653
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• 2019

Laundry services are becoming more specialized and diversified. Therefore, this study investigated consumers' perceptions of professional laundry shops by analyzing social media data. For this purpose, text data from blogs, cafés, and Q&A sections ('Ji-Sik-In') on the portal site, naver.com, was collected. Sixty-four keywords were extracted from 2,213 social texts and transformed into a one-mode matrix using KrKwic, a program for the analysis of Korean text. Semantic network analysis was conducted to understand the network structure and the results were visualized using NodeXL. Keywords included fashion items and materials that require specialized professional laundry services, words related to the establishment of laundry shops, and laundry shop brands. Essential keywords of professional laundry shops included 'luxury,' 'footwear,' 'removal,' 'bag,' 'leather,' 'sneakers,' 'padding,' 'premium,' 'dyeing,' and 'franchise.' These results could be used to deduce that consumers perceive a professional laundry shop as a franchise shop offering specialized professional laundry services. A cluster analysis was conducted to identify the types of consumer perceptions of professional laundry shops. The network was divided into three groups: 'specialized professional laundry service,' 'laundry and repair of winter coats and jackets,' and 'the establishment of a professional laundry shop.' According to the results, consumers perceive professional laundry shops as franchises that offer specialized professional laundry services rather than general laundry services. Therefore, professional laundry shops need a strategy to develop special laundry services that differentiate them from other companies and communicate with consumers about these services.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.6
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• pp.499-508
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• 2007

Background and Purpose: Some subtypes of malignant salivary gland tumors such as adenoid cystic carcinoma (ACC) frequently result in distant metastasis of vascular origin, which are main causes of treatment failure. The reasons for the affinity for vascular metastatic potential are unclear. Therefore, molecular characteristics that influence the dissemination of metastatic tumor cells are important for the design of more effective treatment of salivary ACC. Tumor angiogenesis has been known to be essential for the distant metastasis of malignant cells. So, we determined expressions of vascular metastasis related factors in orthotopic (parotid) murine models of parotid ACC and compared with those in ectopic (subcutis) tumors of athymic mice. Experimental Design: Using specimens from murine parotid (orthotopic, experimental group) and subcutaneous (ectopic, control group) tumors, which have developed via transplantation of tumor cells, originated from human parotid ACC, we performed immunohistochemical assays with anti-vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF, FGF2), matrix metalloproteinase (MMP)-9, and interleukin (IL)-8 antibodies. We also performed immunohistochemical assays with VEGF receptor (VEGFR)-1, VEGFR-2, VEGFR-3, and phosphorylated VEGFR-2. Results: Transplantation of human ACC tumor cell $(5{\times}10^5)$ into the parotid and subcutis successfully resulted in orthotopic (parotid) and ectopic (subcutaneous) tumors in athymic mice. Immunohistochemical staining demonstrated higher expression of major angiogenic factors (VEGF, bFGF, MMP-9) in the orthotopic tumors than in ectopic tumors (P<0.05). But the expression level of angiogenic receptors were same in orthotopic and ectopic tumors of parotid ACC. Conclusion: VEGF, bFGF, and MMP-9 could be a good candidates for antiangiogenic therapy for the contol of vascular metastatic lesions of salivary ACC.

• Composites Research
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• v.33 no.4
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• pp.213-219
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• 2020

Recently, global facing environmental issues have been raised caused by plastic waste. Hence, increasing the demand for interest in environmentally friendly materials. In this row, research on engineering composite materials also replacing the synthetic reinforcement by introducing natural fibers. However, focus on the strength and interfacial adhesion between matrix and reinforcement is very essential in natural fiber composite, which is insufficient in the literature. There are number of approaches for improving the mechanical strength of the composites, one of the common methods is to reinforce additive nanoparticles. The present investigation, bio-additives were synthesized utilizing bio-waste, cheap, bio-degradable sea-weed powder that could replace expensive nanomaterials and reinforced into the CFRP composite through Hand lay-up followed by a vacuum process. Mechanical properties were evaluated and analyzed through microanalysis. The results concluded that synthesized additives are effective for improving mechanical properties such as tensile, flexural, impact, and shear strength. Overall, the results confirmed that the fabricated composites have potential applications in the field of engineering applications.

• Proceedings of the SCSK Conference
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• 2003.09b
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• pp.12-25
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• 2003

L-camitine ($\beta$ -hydroxy-${\gamma}$ -trimethyl-ammoniumbutyric acid) is a small water-soluble molecule important in mammalian fat metabolism. It is essential for the normal oxidation of fatty acids by the mitochondria, and is involved in the trans-esterification and excretion of acyl-CoA esters. In this paper, to investigate the relationship between aging and L-camitine, we investigated the effects of in vitro MMP inhibition and activity and expression of UVA-induced MMP 1 in human skin fibroblasts. Fluorometric assays of the proteolytic activities of MMP-l were performed using fluorescent collagen substrates. ELISA (enzyme linked immuno sorbent assay), gelatin-substrate zymography, and RT-PCR ELISA techniques were used for the effects of L-camitine on MMP expression and activity, MMP mRNA expression in UVA irradiated fibroblast. L-camitine inhibited the activities of MMP-l in a dose-dependent manner and the $IC_{50}$/ values calculated from semi-log plots were 2.45mM, and L-carnitine showed strong inhibition on MMP-2 (gelatinase) activity in UVA irradiated fibroblast by zymography. Also, UVA induced MMP expression was reduced 40% by treated with L-carnitine, and MMP-l mRNA expression was reduced dose-dependent manner. Therefore L-carnitine was able to significantly inhibition the MMP activity, regulation of MMP expression in protein and mRNA level. All these results suggest that L-carnitine may be useful as new anti-aging cofactor for protection against UVA induced MMP expression and activity.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.1
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• pp.10-23
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• 2007

Hallmarks of clinical behaviors of adenoid cystic carcinoma(ACC) of salivary glands are the delayed onset of vascular metastasis and poor responses to classical chemotherapeutic agents. Poor prognoses from salivary ACC are caused by lung metastases that are resistant to conventional therapy. Therefore, cellular and molecular characteristics that influence the dissemination of metastatic cells are important for the design of more effective treatment of salivary ACC. Tumor angiogenesis has been known to be essential for the distant metastasis of malignant cells. So, we determined expressions of angiogenic proteins in benign (pleomorphic adenoma) and malignant (ACC, mucoepidermoid carcinoma) tumors of salivary glands and compared each other and to those in oral squamous cell carcinoma. Using surgical specimens, we performed immunohistochemical assays with anti-vascular endothelial growth factor (VEGF), VEGF receptor-2 (VEGFR-2), phosphorylated VEGFR-2 (pVEGFR-2), matrix metalloproteinase (MMP)-9, and interleukin (IL)-8 antibodies. Most angiogenic factors were overexpressed in malignant salivary tumors than in pleomorphic adenoma which is benign nature. Moreover, ACC demonstrated more expression of VEGFR-2 than that of squamous cell carcinoma which used as control. Conclusively, these data show those angiogenic factors produced by salivary gland tumors may affect the propagation and metastasis of malignant cells of salivary tumors, and could be used as biomarkers for the malignant transformation of salivary gland tumors. Prospectively, although further studies will be needed, these biomarkers related to angiogenesis can be molecular targets for the therapy of salivary ACC, which has propensity for delayed vascular metastasis.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.4
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• pp.271-277
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• 2018

Generating an epipolar image which is removed a y-parallax from an original image is an essential technique for creating a 3D stereoscopic model or producing a map. In epipolar image production, there is a method of generating epipolar images by estimating the relative orientation parameters after matching the extracted distinct points in two images and a method of generating epipolar images by using the baseline and rotation angles of the two images after determining the exterior orientation parameters In this study, it was proposed a methodology to generate epipolar images using direction cosine in the exterior orientation parameters of the input images, and a method to use the transformation matrix for easy calculation when converting from the original image to the epipolar image. The applicability of the proposed methodology was evaluated by using images taken from the fixed wing and rotary wing drones. As a result, it was found that epipolar images were generated regardless of the type of drones.

• Korea Journal of Hospital Management
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• v.22 no.4
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• pp.87-101
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• 2017

[Purpose] This study aims to classify of healthcare decline and analyze the corresponding health outcomes among cities in Korea. In pursuing the above, this paper gives the particular attention to draw policy implications. [Methodology/Approach] Public healthcare data of 81 cities between 2014 and 2015 was obtained from the National Medical Center of Korea. A matrix analysis, t-test, ANOVA and multivariate regression were applied. [Findings] The study results indicated that declining cities tend to have the most healthcare resources, compared to growing or maintaining cities. However, accessibility to healthcare appeared to be lower in declining cities. Based on the classification of cities on healthcare decline, 42 out of 81 cities were categorized as a maintain/improvement group, while 39 cities were characterized as decline/depression. The group with a decline/depression type has significantly more healthcare facilities than maintain/improvement type. In contrast, maintain/improvement cities indicated lower incidence of morbidity and mortality than decline/depression cities. Lastly, according to the multivariate regression analysis for the healthcare outcomes by the type of healthcare decline, incidence of morbidity and mortality tended to decrease as the number of healthcare workers, the proportion of people who have healthcare accessibility, and the Timely Relevance Index increased regardless of the number of medical facilities including hospital beds and special beds. [Practical Implications] In conclusion, focusing on the improvement of healthcare accessibility as well as staffing, rather than expanding facilities is essential to set the healthcare policies.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.1
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• pp.61-68
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• 2015

Noise reduction is necessary to compensate for the degradation of recognition performance by various types of noises. Among many noise reduction techniques using microphone array, generalized sidelobe canceller (GSC) has been widely applied to reduce nonstationary noises. The performance of GSC is directly affected by its adaptation mode controller (AMC). That is, accurate target speech detection is essential to guarantee the sufficient noise reduction in pure noise intervals and the less distortion in target speech intervals. Thus, this paper proposes an improved AMC design technique in which the power ratio of the output of fixed beamforming to that of blocking matrix is calculated frequency bandwise and probabilistically modeled by mixture Gaussians for each class. Experimental results show that the proposed algorithm outperforms conventional AMCs in receiver operating curves (ROC) and output SNRs.