• Journal of the Korean Geotechnical Society
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• v.38 no.5
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• pp.47-59
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• 2022

A series of experiments were performed to investigate the design and application of a rubble-ground modification method with grout injection. A small-sized injection machine was designed, and the grouts with various mix proportions were injected into 25 mm aggregate using the designed small-sized injection machine. With the compressive strength of the grout ranging from 20 to 80 MPa, the uniaxial compressive strength of the grout-filling bodies with clean gravels was higher than 1/6th of the strength of grouts themselves. However, this fraction may reduce depending on the interface conditions. The erosion resistance of the hardened grout was evaluated, and it was determined that the grout with a strength greater than 15 MPa did not require erosion consideration. Moreover, a full-scale injection test was performed for 25 cm-sized rubbles in cages with a diameter greater than 1 m and a height of 1.2 m to evaluate the filling characteristics of the grout. Results from this test indicated that the grout flowability sensitively influenced the filling characteristics.

• Geophysics and Geophysical Exploration
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• v.27 no.2
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• pp.119-128
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• 2024

Marine magnetic surveys provide a rapid and cost-effective method for pioneer geophysical survey for many purposes. Sea-surface magnetometers offer high accuracy but are limited to measuring the scalar total magnetic field and require dedicated cruise missions. Shipboard three-component magnetometers, on the other hand, can collect vector three components and applicable to any cruise missions. However, correcting for the ship's magnetic field, particularly viscous magnetization, still remains a challenge. This study proposes a new additional correction method for ship's viscous magnetization effect in vector data acquired by shipboard three-component magnetometer. This method utilizes magnetic data collected simultaneously with a sea-surface magnetometer providing total magnetic field measurements. Our method significantly reduces deviations between the two datasets, resulting in corrected vector anomalies with errors as low as 7-25 nT. These tiny errors are possibly caused by the vector magnetic anomaly and its related viscous magnetization. This method is expected to significantly improve the accuracy of shipborne magnetic surveys by providing corrected vector components. This will enhance magnetic interpretations and might be useful for understanding plate tectonics, geological structures, hydrothermal deposits, and more.

• Journal of Korea Port Economic Association
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• v.26 no.4
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• pp.188-206
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• 2010

Data Envelopment Analysis(DEA) is an operations research-based method for measuring the performance efficiency of decision units that are characterized by multiple inputs and outputs. DEA has been applied successfully as a performance evaluation tool in many fields. However, it has not been extensively applied in the shipbuilding industry. This paper applied the input-oriented DEA model, and Malmquist indices to the 7 shipbuilding firms to measure the efficiency and productivity changes during the period of 2004 to 2009. The Malmquist indices will be decomposed into three components such as pure efficiency change, scale efficiency change, and technical change. The empirical results show the following findings. First, the DEA findings indicate that main source of inefficiency is scale rather than pure technical. Second, the Malmquist indices show that an overall decrease in productivity.

• Radiation Oncology Journal
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• v.18 no.4
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• pp.314-320
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• 2000

Purpose :To investigate whether changes in plasma concentrations of transforming growth factor-$\beta$1(TGF-$\beta$1), tumor necrosis factor-alpha (TNF-$\alpha$) and interleukin-6 (IL-6) could be used to identify the development of radiation-induced pneumonitis in the lung cancer patients. Methods and Materials :Seventeen patients with lung cancer (11 NSCLC, 6 SCLC) were enrolled in a prospective study designed to evaluate clinical and molecular biologic correlation of radiation-induced pneumonitis. The study began in May 1998 and completed in July 1999. All patients were treated with radiotherapy with curative intent : 1.8 Gy per day, 5 fractions per week. Serial measurements of plasma TGF-$\beta$1, TNF-$\alpha$ and IL-6 were obtained in all patients before, weekly during radiotherapy and at each follow-up visits after completion of treatment. These measurements were quantified using enzyme linked immunosorbent assay (ELISA). All patients were evaluated for signs and symptoms of pneumonitis at each follow-up visit after completion of radiotherapy. High resolution CT (HRCT) scans were obtained when signs and symptoms of pneumonitis were developed after completion of radiotherapy. Results : Thirteen patients eventually developed signs and symptoms of clinical pneumonitis 씬file four patients did not. TGF-$\beta$ 1 levels were elevated in all 13 patients with pneumonitis, which showed characteristic pattern of elevation (38.45 ng/ml at pretreatment, 13.66 ng/ml during radiotherapy, then 60.63 ng/ml at 2-4 weeks after completion of radiotherapy). The levels of TNF- $\alpha$ and IL-6 were also elevated In the group of patients who developed pneumonitis but the pattern was not characteristic. Conclusions : Changes in plasma TGF$\beta$-1 levels before, during and after radiotherapy appears to be a useful means by which to identify patients at risk for the development of symptomatic pneumonitis. Other cytokines like TNF- $\alpha$ and IL-6 shows no meaningful changes in association with radiation pneumonitis.

• Korean Journal of Environmental Agriculture
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• v.27 no.2
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• pp.150-155
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• 2008

This study was carried out to determinate the location and the number of air inlet and outlet, optimum air inlet velocity for effective ventilation in windowless weaning piglet house($2.90(W){\times}9.90(L){\times}2.80(H)$ m) by CFD(Computation Fluid Dynamics) simulation. The weaning piglet house for this experiment was consisted of 11 air inlets and 9 outlets, modified and simulated using CFD code, FLUENT. The simulation result for the original weaning piglet house, which was not modified, showed ununiform ventilation for each room. Therefore, for uniform ventilation, 4 air inlets and 1 outlet were completely closed, and 2 air outlets were partially closed. The simulation result for the modified weaning piglet house showed uniform ventilation for each room and the optimum air inlet velocity of 0.5 $m\;sec^{-1}$.

• Journal of Digital Convergence
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• v.11 no.2
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• pp.341-346
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• 2013

Objectives: This study was designed to provide basic data that would be helpful in planning mental health programs designed to help elderly people have a satisfying life as an elder by identifying the factors that affect cognition of urban and rural elderly people. Methods: Subjects included 160 elderly people on Daejeon and Geumsam. Structured questionnaires were used for data collection from march 2, 2011 to July 30, and descriptive statistics, t-test, ANOVA, Pearson correlation coefficients, and hierarchical regression analysis of SPSS 18.0 program were performed for data analysis. Results: A significant difference in cognition was observed between two groups(t=-2.232, p=.029). Cognition & depression didn't have correlation(urban area(r=.021, p=.860), rural area(r=.-131, p=.271)). Significant factors influencing cognition included education(t=4.069, p<.001) and age(t=-2.812, p=.001) in urban area and sex(t=-3.011, p<.001), age(t=-4.866, p<.001), education(t=3.525, p<.001) in rural area. These factors explained 26.1% and 57.2% of the variance. Conclusion: Findings of this study suggest the need for development of appropriate nursing strategies depending on the difference of the environment to increase cognitive function and to decrease the incidence of depression in elderly people.

• Journal of Digital Convergence
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• v.14 no.5
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• pp.263-271
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• 2016

Localizing an object in image is a common task in the field of computer vision. As the existing methods provide a detection for the single object in an image, they have an utilization limit for the use of the application, due to similar objects are in the actual picture. This paper proposes an efficient method of object localization for image recognition. The new proposed method uses color correlation back-projection in the YCbCr chromaticity color space to deal with the object localization problem. Using the proposed algorithm enables users to detect and locate primary location of object within the image, as well as candidate regions can be detected accurately without any information about object counts. To evaluate performance of the proposed algorithm, we estimate success rate of locating object with common used image database. Experimental results reveal that improvement of 21% success ratio was observed. This study builds on spatially localized color features and correlation-based localization, and the main contribution of this paper is that a different way of using correlogram is applied in object localization.

• Journal of Digital Convergence
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• v.14 no.5
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• pp.237-245
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• 2016

Anxiety for employment of workers has been increased due to rapid change of management environment, which tends to increase psychological instability on the job of all workers. Accordingly, this study examined the moderating effect of self-efficacy between job instability and organizational citizenship behavior. The research subjects were employees of small and medium companies in the manufacturing industry in Daejeon-si, Sejong-si and Chungcheongnam-do and Chungcheongbuk-do. 500 sheets of the questionnaire were distributed from August 5, 2015 to August 30, 2015. Among them, 321 were collected with 64.2% of the response rate. Total 312 sheets were used for analysis excluding 9 sheets with incomplete answers. The results are as follows. Firstly, it proved that job instability had negative (-) effect on organizational citizenship behavior. Secondly, in the relation between job instability and organizational citizenship behavior, there was moderating effect of self-efficacy. Accordingly, if self-efficacy of the workers is higher in the threat of job instability, it means organizational citizenship behavior would increase. In conclusion, in the current situation where there is instable survival of corporation and job, the management of small and medium manufacturing company needs to increase self-efficacy through training and internal reward to employees. The limit of the study is that the research subjects were employees of small and medium companies in the manufacturing industry in Daejeon-si, Sejong-si and Chungcheongnam-do and Chungcheongbuk-do. Accordingly, as situational peculiarity may be observed, it is required to have expanded study to more various areas, works and industries.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.4 no.2
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• pp.142-147
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• 2001

Purpose: We are going to establish the efficacy of endoscopic examinations in diagnosing and treating upper GI bleeding in full term neonates. Methods: We retrospectively reviewed newborns who underwent endoscopic examination because of hematemesis from July 1998 to April 2001. Results: Gestational ages were between 38 and 41weeks, and birth weights were between 2,730 and 3,400 gm. Total of 9 patients were reviewed. Endoscopic examination revealed gastric ulcer in 6 cases, multiple erosions in 2 cases and negative finding in 1 case. All 6 gastric ulcers were multiple and among them 2 patients endoscopic hemostatic therapy. No complication due to the procedure was noticed. Five patients recieved transfusions. All 9 cases were cured through conservative and endoscopic therapy without recurrence. Conclusion: The common cause of upper GI hemorrhage in newborns with no preceding disease turns out to be multiple gastric ulcers and the prognosis is good. The endoscopic approach is useful in diagnosing and treating upper GI bleeding in newborns.

• Composites Research
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• v.30 no.5
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• pp.323-330
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• 2017

In this study, multiscale analysis in which the information obtained from molecular dynamics simulation is applied to the continuum mechanics level is conducted to investigate the effects of clustering of silicon carbide nanoparticles reinforced into polypropylene matrix on mechanical behavior of nanocomposites. The elastic behavior of polymer nanocomposites is observed for various states of nanoparticulate agglomeration according to the model reflecting the degradation of interphase properties. In addition, factors which mainly affect the mechanical behavior of the nanocomposites are identified, and new index 'clustering density' is defined. The correlation between the clustering density and the elastic modulus of nanocomposites is understood. As the clustering density increases, the interfacial effect decreased and finally the improvement of mechanical properties is suppressed. By considering the random distribution of the nanoparticles, the range of elastic modulus of nanocomposites for same value of clustering density can be investigated. The correlation can be expressed in the form of exponential function, and the mechanical behavior of the polymer nanocomposites can be effectively predicted by using the nanoparticulate clustering density.