• Journal of the Society of Disaster Information
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• v.19 no.2
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• pp.372-382
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• 2023

Purpose: Suggests measures to improve the construction company's safety management system according to the enforcement of the Severe Accident Punishment Act. Method: The effectiveness of practice-oriented disaster prevention activities was analyzed through safety and health diagnosis of the level of safety and health management system for the countermeasures against the Severe Accident Punishment Act implemented at the construction site and headquarters. Result: The effect of reducing the accident rate and the advancement of the safety and health management system were analyzed by linking the Severe Accident Punishment Act with the safety and health management system, and a plan to improve the safety and health management system was presented through the analysis of the comprehensive results of safety activities before and after the implementation of the Severe Accident Punishment Act. Conclusion: The effect of practical performance measurement was manifested through the improvement of business owners' awareness, the expansion of investment for disaster prevention, and the quantification of disaster prevention activities according to the enforcement of the Severe Accident Punishment Act.

• Journal of the Korean Geotechnical Society
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• v.22 no.11
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• pp.75-87
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• 2006

A series of calibration chamber tests are performed to investigate the spatial distribution of the excess porewater pressure due to piezocone penetration into overconsolidated clays. It was observed that the excess porewater pressure increases monotonically from the piezocone surface to the outer boundary of the shear zone and then decreases logarithmically, approaching zero at the outer boundary of the plastic zone. It was also found that the size of the shear zone decreases from approximately 2.2 to 1.5 times the cone radius with increasing OCR, while the plastic radius is about 11 times the piezocone radius, regardless of the OCR. Based on the modified Cam clay model and the cylindrical cavity expansion theory, the expressions to predict the Initial porewater pressure at the piezocone were developed, considering the effects of the strain rate and stress anisotropy. The method of predicting the spatial distribution of excess porewater pressure proposed in this study was verified by comparing it with the porewater pressure measured in overconsolidated specimens in the calibration chamber.

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1280-1286
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• 2023

MgF₂ as a moderator material has been extensively used in the beam shaping assembly (BSA) that plays an important role in the boron neutron capture therapy (BNCT). Regarded as important for applications, the thermal neutron scattering data of MgF₂ were calculated, based on the phonon expansion model. The structural properties of MgF₂ were researched by the VASP code based on the ab-initio methods. The PHONOPY code was employed to calculate the phonon density of states. Furthermore, the NJOY code was used to calculate the thermal neutron scattering data of MgF₂. The calculated inelastic cross sections plus absorption cross sections are in agreement with the available experimental data. The neutron transport in the BSA has been simulated by using a hybrid Monte-Carlo-Deterministic code NECP-MCX. The results indicated that compared with the calculation of the free gas model, the thermal neutron flux and epithermal neutron flux at the BSA exit port calculated by using the thermal neutron scattering data of MgF₂ were reduced by 27.7% and 8.2%, respectively.

• Nuclear Engineering and Technology
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• v.55 no.7
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• pp.2556-2566
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• 2023

A first-principle approach within the framework of density functional theory was employed to study the effect of vacancy defects and fission products (FPs) doping on the mechanical, electronic, and thermodynamic properties of uranium monocarbide (UC). Firstly, the calculated vacancy formation energies confirm that the C vacancy is more stable than the U vacancy. The solution energies indicate that FPs prefer to occupying in U site rather than in C site. Zr, Mo, Th, and Pu atoms tend to directly replace U atom and dissolve into the UC lattice. Besides, the results of the mechanical properties show that U vacancy reduces the compressive and deformation resistance of UC while C vacancy has little effect. The doping of all FPs except He has a repairing effect on the mechanical properties of U_1-xC. In addition, significant modifications are observed in the phonon dispersion curves and partial phonon density of states (PhDOS) of UC_1-x, Zr_xU_1-xC, Mo_xU_1-xC, and Rh_xU_1-xC, including narrow frequency gaps and overlapping phonon modes, which increase the phonon scattering and lead to deterioration of thermal expansion coefficient (α_V) and heat capacity (C_p) of UC predicted by the quasi harmonic approximation (QHA) method.

• Journal of the Korean Society of Safety
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• v.10 no.3
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• pp.120-129
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• 1995

Since the rate and completeness of combustion in direct injection engines were controlled by the characteristics of gas flow fields and sprays, an understanding of those was essential to the design of the direct injection engines. In this study the numerical simulations of swirl effects on the characteristics of gas flow fields and sprays were performed using the spray model that could predict the interactions between gas fields and spray droplets. The governing equations were discretized by the finite volume method and the modified k- e model which included the compressibility effects due to the compression/expansion of piston was used. The results of numerical calculation of the spray characteristics in the quiescent environment were compared with the experimental data. There were good agreements between the results of calculation and the experimental data, except in the early stages of spray. In the motoring condition, the results showed that a substantial air entrainment into the spray volume was emerged and hence the squish motion was relatively unimportant during fuel injection periods. As the swirl ratio increased, the evaporation rate was increased due to the wide dispersion of the spray droplets and the strong interaction between spray droplets and gas fields.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.296-299
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• 2022

The rapid urban expansion and the increase in natural disasters due to the increase of population after industrialization and climate change are causing numerous urban management problems. The IP based hyper-connectivity caused by the initiation of the 4th industrial revolution enables a variety of technologies and services that produce vast amounts of data and solve urban management problems based on this. Especially, the quality of life is improved by providing the necessary information for life that are produced through a sensor network on wired and wireless communication. In this study, we intend to propose the method of optimal communcation network composition for innovative and futuristic city management technology through the case of K-water Smart Village Communication System

• The Journal of the Korea Contents Association
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• v.22 no.8
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• pp.274-287
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• 2022

Competition in the broadcasting market is intensifying as OTT services are spreading. And Korea is positioned as a competent international contents supply base. This can be helpful for the domestic contents production industry. However, it can result in being incorporated as a subcontractor in the global video industry. Therefore, it is necessary for Korean OTT operators to expand their market upto overseas and maintain competitiveness by linking content competitiveness to the sales expansion. This study was conducted to reduce the risk and encourage implementation through feasibility analysis of overseas business of domestic OTT operators. The North American market was selected as a region with high potential through in-depth interviews with experts and literatures review. And it was confirmed that the partnership with local platform is effective. Then, the sales and input costs were estimated, and business was evaluated using the net present value method. Totally 18 scenarios were created using multiple estimates for copyright cost, subscribers, and rate, which are highly uncertain. From the analyses, 8 scenarios were found to be acceptable. And copyright cost has the greatest impact on business success, followed by rates and subscribers.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.264-266
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• 2022

In order to apply the RNN model to the radio fingerprint-based indoor path generation technology, the data set must be continuous and sequential. However, Wi-Fi radio fingerprint data is not suitable as RNN data because continuity is not guaranteed as characteristic information about a specific location at the time of collection. Therefore, continuity information of sequential positions should be given. For this purpose, clustering is possible through classification of each region based on signal data. At this time, the continuity information between the clusters does not contain information on whether actual movement is possible due to the limitation of radio signals. Therefore, correlation information on whether movement between adjacent clusters is possible is required. In this paper, a deep learning network, a recurrent neural network (RNN) model, is used to predict the path of a moving object, and it reduces errors that may occur when predicting the path of an object by generating continuous location information for path generation in an indoor environment. We propose a method of giving correlation between clustering for generating an improved moving path that can avoid erroneous path prediction that cannot move on the predicted path.

• Korean Journal of Social Welfare Studies
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• v.42 no.1
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• pp.151-177
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• 2011

With the expansion of Voucher program, academic and practical concerns of performance evaluation of voucher service has been more emphasized. Accordingly, client satisfaction survey are expanding these days, but the study of client satisfaction as a performance indicator aimed at service client has not been yet conducted systematically. The purpose of this study is to develop Satisfaction Index, targeting at client of community-development voucher program in Community Service Investment Project conducted by the Ministry of Health and Welfare. Data were collected from 1800 client of community-development voucher program. This study summarized theoretically many kinds of satisfaction measurement and composed the Satisfaction Index reflecting characteristics of Voucher. By the item analysis and reliability analysis, the element satisfaction was identified as homogeneous items. General satisfaction were obtained using element satisfaction and overall satisfaction, it was found to be valid through the evaluation of convergent and discriminant validity as a tool for satisfaction. This study suggest using the '1step weighted approach' than '2step weighted approach' having weakness of complex overlapping manner.

• Journal of Internet Computing and Services
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• v.24 no.6
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• pp.57-64
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• 2023

This study analyzed the perceptions of elementary and secondary school teachers regarding the importance of SW/AI education in fostering students' fundamental knowledge and the necessity of integrating SW/AI into education. A total of 830 elementary and secondary school teachers were selected as study subjects using the judgment sampling method. The analysis of survey data revealed that elementary and secondary teachers exhibited a strong awareness of the importance and necessity of SW/AI education, irrespective of school characteristics, region, educational experience, or prior involvement in SW and AI education. Nevertheless, the primary reasons for not implementing SW/AI education were identified as excessive workload and a lack of pedagogical expertise. An analysis of opinions on the essential conditions for implementing SW/AI education revealed that workload reduction, budget support, teacher training to enhance teacher competency, content distribution, expansion of subject-linked courses, and dedicated instructional time allocation were the major influencing factors. These findings indicate a significant demand for comprehensive instructional support and teacher capacity-building programs.