• Korean Journal of Materials Research
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• v.28 no.11
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• pp.680-684
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• 2018

We investigate the effect of light intensity and wavelength of a solar cell device using photoconductive atomic force microscopy(PC-AFM). A $POCl_3$ diffusion doping process is used to produce a p-n junction solar cell device based on a polySi wafer, and the electrical properties of prepared solar cells are measured using a solar cell simulator system. The measured open circuit voltage($V_{oc}$) is 0.59 V and the short circuit current($I_{sc}$) is 48.5 mA. Moreover, the values of the fill factors and efficiencies of the devices are 0.7 and approximately 13.6 %, respectively. In addition, PC-AFM, a recent notable method for nano-scale characterization of photovoltaic elements, is used for direct measurements of photoelectric characteristics in limited areas instead of large areas. The effects of changes in the intensity and wavelength of light shining on the element on the photoelectric characteristics are observed. Results obtained through PC-AFM are compared with the electric/optical characteristics data obtained through a solar simulator. The voltage($V_{PC-AFM}$) at which the current is 0 A in the I-V characteristic curves increases sharply up to $18W/m^2$, peaking and slowly falling as light intensity increases. Here, $V_{PC-AFM}$ at $18W/m^2$ is 0.29 V, which corresponds to 59 % of the average $V_{oc}$ value, as measured with the solar simulator. Furthermore, while the light wavelength increases from 300 nm to 1,100 nm, the external quantum efficiency(EQE) and results from PC-AFM show similar trends at the macro scale but reveal different results in several sections, indicating the need for detailed analysis and improvement in the future.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.4
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• pp.22-33
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• 2018

Recently domestic manufacturing companies have been experiencing worsening profitability and stunted growth due to the long-term economic recession and the rapid rise of developing countries such as China and Southeast Asia. These difficulties force many companies to concentrate their core competencies on new value creation and innovation in order to gain momentum for new growth. Enterprise Resource Planning (ERP) has been considered as one of viable solutions. Among the various modules in ERP, shop floor control function in the production management module is rather limited. In order to overcome this problem, Manufacturing Execution System (MES) has been used as a subsystem which has a strong information gathering power and flexibility. Both systems interact closely with each other. In particular, ERP requires fast, accurate shop floor information at MES. This paper describes how to synchronize relevant information between ERP and MES with theory of constraints (TOC). The processing time information transmitted from the MES workplace is received at the ERP workplace. In the process, the received processing time is causing information distortion in ERP, when the information gathering standard of MES is different from the ERP information interpretation standard. The Drum-Buffer-Rope theory of TOC was applied to resolve this problem, therefore, information synchronization between both systems was made. As a precondition, the standard time of the upper ERP system was rearranged according to the capacity constraints resource. As a result, standard time restructuring has affected changes in labor costs. Standard labor costs have come close to actual ones, and information synchronization of MES transmission data has improved the reliability of standard product costs, such that it enabled various company-wide restructuring actions to be much more effective.

• Journal of the Korea Convergence Society
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• v.10 no.7
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• pp.121-131
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• 2019

Art Collaborative advertising uses creative works that are not related directly to the product and recreates it as a more valuable product. Creative thinking acts as a core value. The purpose of this study is to investigate the effect of creative thinking using mind map and SCAMPER technique in art collaboration class. After analyzing the art collaboration advertisement class for 6 students in middle school, we analyzed characteristics between creative technique and creativity through student activities and work. The results were as follows. First, creative thinking ability of students who experienced art collaboration showed flexibility and originality in SCAMPER, and fluency in mind map. Second, throughout the course, we were able to observe elaboration, which embodied tough ideas and developed depth. This study will contribute to the research related to the improvement of students' creative convergence case by meeting two or more areas and collaborating on each core competency.

• Clinical and Experimental Pediatrics
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• v.61 no.12
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• pp.392-396
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• 2018

Purpose: Adenotonsillar hypertrophy (ATH) that causes upper airway obstruction might lead to chronic hypoxemic pulmonary vasoconstriction and right ventricular (RV) dysfunction. We aimed to evaluate whether adenotonsillectomy (T&A) in children suffering from obstructive sleep apnea (OSA) due to severe ATH could improve RV function. Methods: Thirty-seven children (boy:girl=21:16; mean age, $9.52{\pm}2.20years$), who underwent T&A forsleep apnea due to ATH, were included. We analyzedthe mean pulmonary artery pressure (mPAP), the presence and the maximal velocity of tricuspid regurgitation (TR), the tricuspid annular plane systolic excursion (TAPSE), and the right ventricular myocardial performance index (RVMPI) with tissue Doppler echocardiography (TDE) by transthoracic echocardiography pre- and post-T&A. The follow-up period was $1.78{\pm}0.27years$. Results: Only the RVMPI using TDE improved after T&A ($42.18{\pm}2.03$ vs. $40{\pm}1.86$, P=0.001). The absolute value of TAPSE increased ($21.45{\pm}0.90mm$ vs. $22.30{\pm}1.10mm$, P=0.001) but there was no change in the z score of TAPSE pre- and post-T&A ($1.19{\pm}0.34$ vs. $1.24{\pm}0.30$, P=0.194). The mPAP was within normal range in children with ATH, and there was no significant difference between pre- and post-T&A ($19.6{\pm}3.40$ vs. $18.7{\pm}2.68$, P=0.052). There was no difference in the presence and the maximal velocity of TR (P=0.058). Conclusion: RVMPI using TDE could be an early parameter of RV function in children with OSA due to ATH.

• The Korean Journal of Pain
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• v.32 no.4
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• pp.256-263
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• 2019

Background: Antinociceptive anti-inflammatory drugs have many adverse effects. The goal of this investigation is to study the probable anti-inflammatory and analgesic effects of verapamil and N-acetylcysteine (NAC) in experimental rats. Methods: Adult male Wistar rats were randomly divided into 4 groups in the antinociceptive study, each containing 6 rats; the normal control group, which received saline (1 mL/kg); the diclofenac group, which received diclofenac sodium (5 mg/kg); the NAC group, which received NAC (125 mg/kg); and the verapamil group, which received verapamil (8 mg/kg). In the anti-inflammatory study, 5 groups were used, the 4 previous groups with the addition of an edema control group, received saline and were subjected to formalin test. Hot plate latency time was recorded for antinociceptive evaluation. Paw edema thickness and biochemical parameters were recorded for anti-inflammatory evaluation. Results: Administration of NAC showed significant prolongation of hot plate latency time at 1 hour when compared to the control group while verapamil showed a significant prolongation of hot plate latency time at 1 and 2 hours when compared to the control group and NAC group values. Administration of NAC and verapamil significantly decreased paw edema thickness at 2, 4, and 8 hours when compared to edema control values. Regarding biochemical markers, NAC and verapamil significantly decreased serum nitric oxide synthase, C-reactive protein, and cyclooxygenase-2 levels compared to the edema control value. In accordance, a marked improvement of histopathological findings was observed with both drugs. Conclusions: NAC and verapamil have antinociceptive and anti-inflammatory effects comparable to diclofenac sodium.

• Journal of Digital Convergence
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• v.17 no.9
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• pp.367-373
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• 2019

In modern society, with the changing lifestyle, demand for complex cultural spaces is rising and various cultural spaces are emerging. However, user-centered cultural space research has not yet been shown. In order to find out whether various cultural experience functions and user experience types of complex cultural spaces are being delivered properly, this study compared and analyzed the representative cultural spaces of Korea, 'Starfield Library' and 'ARC.N.BOOK'. User experience analysis tools and individual in-depth interviews were used as research methods. As a result, both spaces responded that commercial space and brand library were out of harmony and that the use of services in complex cultural spaces was inconvenient. This is interpreted as the result of the need for improvement measures in the value and usability of experience provided by the current complex cultural space and is expected to help develop the complex cultural space in the future.

• Journal of the Korea Convergence Society
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• v.10 no.10
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• pp.197-205
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• 2019

The purpose of this research was examining the effects of problem-based learning strategies(PBL) on problem solving skill conducted in Korea, using meta-analysis technique. This meta-analysis reviewed the results of 41 studies published between 1998 and 2017 in Korea. The overall weighted mean effect size value was .753 with .064 standard error which was calculated by random effects model. PBL strategies have been found to be more effective in mathematics course (d=.922), art course (d=.916), practical art course (d=.827), E-PBL (d=.791) and middle school level (d=.972). As PBL exhibit a substantial effect on students' problem solving skill, it is recommended that teachers should learn how to implement these strategies in their lesson. PBL is expected to contribute to the improvement of teaching methods as the learning environment changes during the 4th Industrial Revolution.

• Convergence Security Journal
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• v.17 no.5
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• pp.179-186
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• 2017

The purpose of this study is to analyze the relation of security officers' martial arts training and job performance. To this end, we conducted surveys on security practitioners. The questionnaire consisted of three variables, "necessity of martial arts training, application to practical security work, improvement of job satisfaction". In this study for reliability analysis, Chronbach's Alpha coefficient was calculated. In order to verify the validity of the measured variables, exploratory factors were analyzed using the Berimax method. Both AVE and CR values of the measured variables were above the reference value of 0.5, indicating that the convergence validity was good. As a result of the hypothesis test, the standardization coefficient is 0.636 for "need for training in martial arts training${\Rightarrow}$practical security work", 0.986 for "practical security work${\Rightarrow}$job satisfaction improving", and the relationship between the two hypotheses is positive(+). In order to improve the job satisfaction of security-related practitioners, it seems necessary to raise the need for martial arts training.

• Journal of the Korea Convergence Society
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• v.10 no.10
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• pp.259-266
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• 2019

The purpose of this study was to examine the need for changes in the administration strategies of hospitals which would be vital for building up competitiveness of hospitals amid the changes in medical market. For that, 20 experts with doctoral degree in public administration and business administration related to the field of hospital administration were selected as the sampling group in the survey. Regarding the method of AHP survey as in this survey. The results showed that the factors were important in the order of medical staff factor(ranked first), overall facility factor(ranked second), staff service factor(ranked third), and access factor(ranked fourth). Second, the relative importance was in the order of medical staff specialization(ranked first), medical staff diversity(ranked second), and medical equipment level(ranked third), regarding the relative importance for general hospital development strategy and the complex weighted value for relative importance.

• Journal of the Korean Society of Safety
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• v.34 no.1
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• pp.62-69
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• 2019

Korean shipbuilding companies have taken many efforts for safety over the years by developing Health, Safety & Environment (HSE) Management Systems, Procedures, Training, and studying Programs for prevention of incidents. As a result, the shipbuilding industry has succeeded in reducing overall injury rates. Nevertheless, the industry also noticed that incident rates are still not at zero and more importantly, serious injuries and fatalities are still occurring. One factor that may be attributing to this is the lack of managing potential severity during incident investigations, most incident investigations are implemented based on the actual result. Generally, each shipbuilding company develops their customized incident investigation programs and these are also commonly being focused on actual result. This study aimed to develop a shift in strategy toward safety to classify the criteria of potential severity from any incidents and manage that to prevent any recurrence or causing any serious injuries or fatalities in the shipbuilding industry. Several global energy companies have already developed potential severity management tools and applied them in their incident investigations. In order to verify the necessity of improvement for current systems, a case study and comparative analysis between a domestic shipbuilding company and several global energy companies from foreign countries was implemented and comparison of two incident investigation cases from specific offshore projects was conducted to measure the value of a potential severity system. Also, a checklist was established from the data of fatalities and serious injuries in recent 5 years that occurred in Korea shipbuilding industry and a proposal to verify high potential incidents in the incident investigation process and comparative analysis between the assessment by appling proposed checklist and the assessment from a global energy company by using their own system was implemented. As a measure to prevent any incidents, it is required to focus on potential severity assessment during the incident investigation rather than to only control actual result. Hence, this study aims to propose a realistic plan which enables to improve the existing practices of incident investigation and control in the shipbuilding industry.