• Journal of Ocean Engineering and Technology
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• v.36 no.2
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• pp.101-107
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• 2022

Dean (1965) proposed the use of the root mean square error (RMSE) in the dynamic free surface boundary condition (DFSBC) and kinematic free-surface boundary condition (KFSBC) as an error evaluation criterion for wave theories. There are well known wave theories with RMSE more than 1%, such as Airy theory, Stokes theory, Dean's stream function theory, Fenton's theory, and trochodial theory for deep-water waves. However, none of them can be applied for deep-water breaking waves. The purpose of this study is to provide a closed-form solution for deep-water waves with RMSE less than 1% even for breaking waves. This study is based on a previous study (Shin, 2016), and all flow fields were simplified for deep-water waves. For a closed-form solution, all Fourier series coefficients and all related parameters are presented with Newton's polynomials, which were determined by curve fitting data (Shin, 2016). For verification, a wave in Miche's limit was calculated, and, the profiles, velocities, and the accelerations were compared with those of 5^th-order Stokes theory. The results give greater velocities and acceleration than 5^th-order Stokes theory, and the wavelength depends on the wave height. The results satisfy the Laplace equation, bottom boundary condition (BBC), and KFSBC, while Stokes theory satisfies only the Laplace equation and BBC. RMSE in DFSBC less than 7.25×10^-2% was obtained. The series order of the proposed method is three, but the series order of 5^th-order Stokes theory is five. Nevertheless, this study provides less RMSE than 5^th-order Stokes theory. As a result, the method is suitable for offshore structural design.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.661-666
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• 2022

This study verified the influence of supervision on job burnout and mediating effect of self-efficacy of workers in leisure welfare centers for the elderly. A survey of 275 employees of 15 facilities of Daejeon and Chungnam area was conducted. Main analysis methods are confirmatory factor analysis and structural equation model analysis. The analysis result is that supervision influences job burnout and mediating effect of self-efficacy is proved. Considering the analysis result, some countermeasures can be proposed to alleviate the job burnout. For improving the supervision of workers, the strengthening of educational and evaluational supervision, the provision of education and training for supervisors and individualized supervision, and the inclusion of supervision in facility evaluation are necessary. To improve employees' self-efficacy, it is necessary to provide capacity-building programs and emotional support services, education and administrative support for improving ethical awareness, and self-leadership.

• The Journal of the Korea Contents Association
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• v.22 no.7
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• pp.126-135
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• 2022

Decentralization is a structural characteristic surrounding the allocation of power within an organization and is discussed at the organizational, national and local levels. This study examined the evaluation and decentralization direction of decentralization of public officials to derive problems and development directions of decentralization in Korea. We also derive our decentralization task. The decentralization task is, first, the expansion of autonomy in organization composition. The organization of local governments shall be determined according to the details and amount of local affairs. Second, it is to secure autonomy in personnel management. It is desirable for local governments to handle local gardens and manpower management autonomously rather than central uniform control. However, it is necessary to leave the checks and supervision to the local council, civic groups, and local residents. Third, the expansion of fiscal decentralization. First of all, the tax rate should be determined by ordinance within the scope prescribed by law to expand the autonomous financial authority. Next, it is necessary to expand local finances through the conversion of national taxes to local taxes. Next, it is necessary to expand local income taxes and local consumption taxes. Decentralization requires cooperation between the central and local governments and participation of local residents and stakeholders, breaking away from central unilateral and short-term thinking.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.5
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• pp.99-117
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• 2022

This study examines the effect of customer experience management capability of a bank and job satisfaction and customer orientation of the frontline employee in bank. The proposed research model and developed hypotheses were tested using structural equations modeling based on data collected from 321 employees working in banks. The results of the study confirm the positive effects of employee training, employee empowerment, employee evaluation, cross functional work of customer experience management capability is job satisfaction and customer orientation. But channel integration is not supported job satisfaction and customer orientation. Performance management influenced customer orientation through job satisfaction. The study provides On a theoretical level valuable insights into the customer experience management competency at the organizational unit and but there is also a limitation that firms the is limited.

• Journal of Korea Multimedia Society
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• v.25 no.1
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• pp.1-9
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• 2022

Ship detection in synthetic aperture radar (SAR) images is an important application in marine monitoring for the military and civilian domains. Over the past decade, object detection has achieved significant progress with the development of convolutional neural networks (CNNs) and lot of labeled databases. However, due to difficulty in collecting and labeling SAR images, it is still a challenging task to solve SAR ship detection CNNs. To overcome the problem, some methods have employed conventional data augmentation techniques such as flipping, cropping, and affine transformation, but it is insufficient to achieve robust performance to handle a wide variety of types of ships. In this paper, we present a novel and effective approach for deep SAR ship detection, that exploits label-rich Electro-Optical (EO) images. The proposed method consists of two components: a data augmentation network and a ship detection network. First, we train the data augmentation network based on conditional generative adversarial network (cGAN), which aims to generate additional SAR images from EO images. Since it is trained using unpaired EO and SAR images, we impose the cycle-consistency loss to preserve the structural information while translating the characteristics of the images. After training the data augmentation network, we leverage the augmented dataset constituted with real and translated SAR images to train the ship detection network. The experimental results include qualitative evaluation of the translated SAR images and the comparison of detection performance of the networks, trained with non-augmented and augmented dataset, which demonstrates the effectiveness of the proposed framework.

• Progress in Medical Physics
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• v.32 no.4
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• pp.92-98
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• 2021

Purpose: This study automatically discriminates homogeneous and structure edge regions on computed tomography (CT) images, and it evaluates the noise level and edge preservation ratio (EPR) according to the different types of iterative reconstruction (IR). Methods: The dataset consisted of CT scans of 10 patients reconstructed with filtered back projection (FBP), statistical IR (iDose⁴), and iterative model-based reconstruction (IMR). Using the 10th and 85th percentiles of the structure coherence feature, homogeneous and structure edge regions were localized. The noise level was estimated using the averages of the standard deviations for five regions of interests (ROIs), and the EPR was calculated as the ratio of standard deviations between homogeneous and structural edge regions on subtraction CT between the FBP and IR. Results: The noise levels were 20.86±1.77 Hounsfield unit (HU), 13.50±1.14 HU, and 7.70±0.46 HU for FBP, iDose⁴, and IMR, respectively, which indicates that iDose⁴ and IMR could achieve noise reductions of approximately 35.17% and 62.97%, respectively. The EPR had values of 1.14±0.48 and 1.22±0.51 for iDose⁴ and IMR, respectively. Conclusions: The iDose⁴ and IMR algorithms can effectively reduce noise levels while maintaining the anatomical structure. This study suggested automated evaluation measurements of noise levels and EPRs, which are important aspects in CT image quality with patients' cases of FBP, iDose⁴, and IMR. We expect that the inclusion of other important image quality indices with a greater number of patients' cases will enable the establishment of integrated platforms for monitoring both CT image quality and radiation dose.

• Journal of Hydrogen and New Energy
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• v.33 no.5
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• pp.574-582
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• 2022

A lithium-ion battery exhibits high energy density but has many limitations due to safety issues. Currently, as a solution for this, research on solid state batteries is attracting attention and is actively being conducted. Among the solid electrolytes, sulfide-based solid electrolytes are receiving much attention with high ion conductivity, but there is a limit to commercialization due to the relatively high price of lithium sulfide, which is a precursor material. This study focused on the possibility of relatively inexpensive and light lithium hydride and conducted an experiment on it. In order to analyze the characteristics of LiAlH₄, ion conductivity and thermal stability were measured, and a composites mixed with PVDF, a representative polymer electrolyte, was synthesized to confirm a change in characteristics. And metallurgical changes in the material were performed through XRD, SEM, and BET analysis, and ion conductivity and thermal stability were measured by EIS and LFA methods. As a result, Li₃AlH₆ having ion conductivity higher than LiAlH₄ is formed by the synthesis of composite materials, and thus ion conductivity is slightly improved, but thermal stability is rapidly degraded due to structural irregularity.

• Journal of Korea Foundry Society
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• v.42 no.4
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• pp.218-225
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• 2022

For hydrogen-vehicle applications (air pressure control valve housing, APCVH), an investigation was conducted to determine how micro-defects in a high- pressure die-casted Al alloy (industrial code: ALDC12) could be controlled by means of a post-treatment using an organic-based impregnation solution in order to improve the air- tightness of the die-casted Al sample. Two different impregnation solutions were proposed and its test results were compared to a imported product from Japan with respect to the processing variables used. A structural investigation of the components under study was conducted by means of computer tomography and 3D X-ray micro-CT. These observations revealed that the use of the impregnation treatment to seal micro-defects led to highly significant and beneficial changes which were attributed mainly to interconnections among inherent micro-pores. A leak test after impregnation revealed that the performance improvement rate of the die-casted Al sample was ~70% for INNO-01. Therefore, the developed impregnation solutions offer an effective strategy to control the micro-defects found in various vehicle parts via die-casting.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.5
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• pp.85-95
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• 2021

Structure design sensitivity was evaluated using the orthogonal array experimental method for passive-type deck support frame (DSF) developed for float-over installation of the offshore plant. Moreover, approximation characteristics were also reviewed based on various meta-models. The minimum weight design of the DSF is significantly important for securing both maneuvering performance and buoyancy of a ship equipped with the DSF and guaranteeing structural design safety. The performance strength of the passive type DSF was evaluated through structure analysis based on the finite element method. The thickness of main structure members was applied to design factors, and output responses were considered structure weight and strength performances. Quantitative effects on the output responses for each design factor were evaluated using the orthogonal array experimental method and analysis of variance. The optimum design case was also identified from the orthogonal array experiment results. Various meta-models, such as Chebyshev orthogonal polynomial, Kriging, response surface method, and radial basis function-based neural network, were generated from the orthogonal array experiment results. The results of the orthogonal array experiment were validated using the meta-modeling results. It was found that the radial basis function-based neural network among the meta-models could approximate the design space of the passive type DSF with the highest accuracy.

• Safety and Health at Work
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• v.11 no.4
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• pp.526-532
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• 2020

Background: The high incidence of work-related diseases and injuries among day-laborers and workers with no legal contracts (informal workers) has received the attention of the Thai authorities. Workers' low occupational health literacy (OHL) has been reasoned as one contributing factor. Absence of a valid tool has prevented assessment of informal workers' OHL. The aim of this study was to create a valid and reliable Occupational Health Literacy Scale within the context of Thai working culture (TOHLS-IF). Methods: This study used the mixed method approach to develop TOHLS-IF. Questions were generated using in-depth interviews and an extensive review of the literature. Experts' assessment confirmed the content validity of TOHLS-IF. The scales of its psychometric properties were assessed in a sample of 400 informal workers using cluster random sampling. Results: The final version of the TOHLS-IF comprises 38 items within 4 dimensions: Ability to Gain Access, Understanding, Evaluation, and Use of occupational health and safety information. Factor analysis identified items explaining 50.22% of the total variance. The final confirmatory analysis confirmed the model estimates were satisfactory for the construct. TOHLS-IF demonstrated a high internal consistency and satisfactory reliability (Cronbach's alpha = .98). Conclusion: The TOHLS-IF is a valid and reliable instrument to assess informal workers' OHL. The structural dimensions of this instrument are based on the concept of health literacy and Thai culture. Thai health professionals are encouraged to benefit from this instrument to assess their workers' OHL and apply findings as guidelines for effective occupational health and safety interventions.