• Journal of Radiation Protection and Research
• /
• v.42 no.2
• /
• pp.114-129
• /
• 2017

Background: The purpose of this paper is to confirm the event timings and the magnitude of fission product aerosol release from the Fukushima accident. Over a few hundreds of technical papers have been published on the environmental impact of Fukushima Daiichi accident since the accident occurred on March 11, 2011. However, most of the research used reverse or inverse method based on the monitoring of activities in the remote places and only few papers attempted to estimate the release of fission products from individual reactor core or from individual spent fuel pool. Severe accident analysis code can be used to estimate the radioactive release from which reactor core and from which radionuclide the peaks in monitoring points can be generated. Materials and Methods: The basic material used for this study are the initial core inventory obtained from the report JAEA-Data/Code 2012-018 and the given accident scenarios provided by Japanese Government or Tokyo Electric Power Company (TEPCO) in official reports. In this research a forward method using severe accident progression code is used as it might be useful for justifying the results of reverse or inverse method or vice versa. Results and Discussion: The release timing and amounts to the environment are estimated for volatile radioactive fission products such as noble gases, cesium, iodine, and tellurium up to 184 hours (about 7.7 days) after earthquake occurs. The in-plant fission product behaviors and release characteristics to environment are estimated using the severe accident progression analysis code, MELCOR, for Fukushima Daiichi accident. These results are compared with other research results which are summarized in UNSCEAR 2013 Report and other technical papers. Also it may provide the physically based arguments for justifying or suspecting the rationale for the scenarios provided in open literature. Conclusion: The estimated results by MELCOR code simulation of this study indicate that the release amount of volatile fission products to environment from Units 1, 2, and 3 cores is well within the range estimated by the reverse or inverse method, which are summarized in UNSCEAR 2013 report. But this does not necessarily mean that these two approaches are consistent.

• Journal of the Korea Convergence Society
• /
• v.10 no.12
• /
• pp.251-255
• /
• 2019

The QR codes are printed in sticker form and have many advantages in terms of location recognition accuracy or installation cost compared to the location recognition method, which attaches artificial indicators to ceilings or walls for low-cost location recognition, and the way in which the location is recognized by vision, to create robots that are generally applicable to all industries. In this study, it is shown that the two-dimensional square bar code applied to the robot within 3 mm of error allows the robot to be made with high accuracy and accurate location control. In particular, the fusion research, combined with various engineering technologies, describes QR code-aware indoor mobile robot control research centered on the construction of the system.

• Nuclear Engineering and Technology
• /
• v.37 no.3
• /
• pp.265-272
• /
• 2005

Severe accidents in nuclear power plants can cause hydrogen-generating chemical reactions, which create the danger of hydrogen combustion and thus threaten containment integrity. For containment analyses, a three-dimensional mechanistic code, GOTHIC-3D has been applied near source compartments to predict whether or not highly reactive gas mixtures can form during an accident with the hydrogen mitigation system working. To assess the code applicability to hydrogen combustion analysis, this paper presents the numerical calculation results of GOTHIC-3D for various hydrogen combustion experiments, including FLAME, LSVCTF, and SNU-2D. In this study, a technical base for the modeling oflarge- and small-scale facilities was introduced through sensitivity studies on cell size and bum modeling parameters. Use of a turbulent bum option of the eddy dissipation concept enabled scale-free applications. Lowering the bum parameter values for the flame thickness and the bum temperature limit resulted in a larger flame velocity. When applied to hydrogen combustion analysis, this study revealed that the GOTHIC-3D code is generally able to predict the combustion phenomena with its default bum modeling parameters for large-scale facilities. However, the code needs further modifications of its bum modeling parameters to be applied to either small-scale facilities or extremely fast transients.

• Earthquakes and Structures
• /
• v.14 no.6
• /
• pp.505-523
• /
• 2018

Static pushover analyses of typical existing reinforced concrete frames, designed according to the previous generations of design codes in Greece, have established these structures' inelastic characteristics, namely overstrength, global ductility capacity and available behaviour factor q, under planar response. These were compared with the corresponding demands at the collapse limit state target performance point. The building stock considered accounted for the typical variability, among different generations of constructed buildings in Greece, in the form, the seismic design code in effect and the material characteristics. These static pushover analyses are extended, in the present study, in the time history domain. Consequently, the static analysis predictions are compared with Incremental Dynamic Analysis results herein, using a large number of spectrum compatible recorded base excitations of recent destructive earthquakes in Greece and abroad, following, for comparison, similar conventional limiting failure criteria as before. It is shown that the buildings constructed in the 70s exhibit the least desirable behaviour, followed by the buildings constructed in the 60s. As the seismic codes evolved, there is a notable improvement for buildings of the 80s, when the seismic code introduced end member confinement and the requirement for a joint capacity criterion. Finally, buildings of the 90s, designed to modern codes exhibit an exceptionally good performance, as expected by the compliance of this code to currently enforced seismic provisions worldwide.

• Journal of Convergence for Information Technology
• /
• v.8 no.2
• /
• pp.91-103
• /
• 2018

Refactoring is an engineering technique for securing the quality of existing legacy code, improving the internal structure without changing the functionality of the software. Along with the reuse of open source software, reuse of source code through programming language conversion is increasingly required due to technical or market requirements. In this situation, the refactoring technique including language conversion as well as energy efficiency is considered to be an important means for improving the productivity and the quality of embedded software development. This paper proposes a code refactoring technique that converts the grammar and structure of a programming language into those of a different language through comparison and mapping, in addition to the existing energy efficient refactoring technique. The use of the proposed refactoring technique can expect to improve the competitiveness of the product through rapid software development and quality improvement by coping with the environment change of the software development language and enhancing the reuse of the existing code.

• Journal of KSNVE
• /
• v.9 no.1
• /
• pp.85-96
• /
• 1999

For ASME Code pumps in nuclear power plants, inservice test is required to assess the operational readiness in accordance with ASME code and related regulations. The objective of this study therefore, is to develop the technical background of the degradation of pump performances and conditions due to low flow rate operation. In addition. the detection techniques of pump operating conditions are to be developed to enhance the safety and economy of nuclear power plants. A test loop consisted of pump, motor. water tank, flow rate measurements and piping system with flow control devices was established for this study. Two typical pumps, 1-stage volute pump and 3-stage turbine pump, were selected and the test was performed upon two major point of views ; i.e., pump discharge pressure pulsations analysis and pump vibration spectrum analysis. From the test results, it is concluded that (1) the pump vibration affected by the natural frequency of operating pump is significant in the low frequency zone (around 1 Hz) : the vibration amplitude. especially. is an important factor during low flow rate operation. and shall be monitored to ensure that it is within the limit of ASME OM code Part 6, (2) the vibration frequency and pump discharge pressure are affected by vane pass frequency and running speed, (3) the wave phenomena due to the compressiblity of water is anticipated during low flow rate operation. and the pump system shall be designed to prevent it and. finally, (4) the technical background of the degradation of pump performances and conditions due to low flow rate operation is provided.

• Journal of the Korea Society of Computer and Information
• /
• v.26 no.9
• /
• pp.189-200
• /
• 2021

Recently, Information and Communication Technology and SMART Phone Technology have been rapidly developed. According to the increase of data use, the era of big data has come. With the approach of non-contact society, QR Codes are becoming inseparable in our lives. In this paper, we are trying to figure out the implications of QR Code research based on Big Data in Korea. The purpose of this study is to first examine the previous studies on "QR Code" and conduct an analysis on keywords by field using Big Data. Second, for data visualization WordCloud analysis and network analysis are performed on "QR Code" frequent keyword. Third, we would like to present the research direction to future researchers regarding "QR Code". In the results, First of all, research trends showed that research is on the rise and that various fields are being utilized. Second, the results of the analysis of frequent keyword resulted in similar results overall, with some differences depending on the field and year. Third, we found that the visualization results according to the frequent keyword were also analyzed in the same way as the frequent keyword analysis results. The practical implications of the theoretical findings are as follows. First, 'QR Code' needs to be studied as a means of information delivery, not as a technical aspect. Second, it can be seen that "QR Code" is developing reflecting social trends or issues. With both theoretical and practical implications, we are trying to provide the strategic ways of QR-code in future.

• Structural Engineering and Mechanics
• /
• v.65 no.4
• /
• pp.369-380
• /
• 2018

In this paper, a multi-layered finite element model for laminated glass plates is introduced. A layer-wise theory is applied to the analysis of laminated glass due to the combination of stiff and soft layers; the independent layers are connected via Lagrange multipliers. The von $K{\acute{a}}rm{\acute{a}}n$ large deflection plate theory and the constant Poisson ratio for constitutive equations are assumed to capture the possible effects of geometric nonlinearity and the time/temperature-dependent response of the plastic foil. The linear viscoelastic behavior of a polymer foil is included by the generalized Maxwell model. The proposed layer-wise model was implemented into the MATLAB code and verified against detailed three-dimensional models in ADINA solver using different hexahedral finite elements. The effects of temperature, load duration, and creep/relaxation are demonstrated by examples.

• Journal of Korea Society of Industrial Information Systems
• /
• v.22 no.3
• /
• pp.19-26
• /
• 2017

In this paper, a Linear Error Correction Code, Which is Applicable to Next Generation Wireless Communication System Technology, is Constructed Based on Performance Comparison and Transmission Based on the Premise of High Performance Mobile Rate Enhancement System. This is Because Data Rates are Becoming an Important Issue in Reed-Solomon Codes and Linear Error Code (LDPC) Used in the Physical Layer of Digital Communication and Broadcasting Technologies. Therefore, this paper Simulates the Performance of Reed - Solomon Code and LDPC Applied to Mobile Broadcasting DVB (Digital Video Broadcasting) System and Mobile Broadcasting in Digital Communication and Broadcasting, At this time, Technical Aspects of the Transmission Efficiency and Performance of the LDPC Replacing the Existing Reed-Solomon Code have been Verified from the Viewpoint of Efficiency.

• Korean Chemical Engineering Research
• /
• v.57 no.2
• /
• pp.225-231
• /
• 2019

In Korea, the minimum separation distance between aboveground high-pressure natural gas pipeline and buildings is regulated by Korea gas safety (KGS) code. In this paper, The technical backgrounds for the revision of the KGS code related to the minimum separation distance was presented. A consequence-based approach was adopted to determine the minimum separation distance by a reasonable accident scenario, which was a jet fire caused by the rupture of one inch branch line attached the gas pipeline. Where, the higher thermal radiation flux threshold was selected for workers in industrial area than for people in non-industrial area, because the workers in industrial area were able to escape in a shorter time than the people in public. As result of consequence analysis for the accident scenario, we suggested the KGS code revision that the minimum separation distances between high-pressure natural gas pipeline installed above ground and buildings should be 30 meter in non-industrial area and 15 meter in industrial area. The revised code was accepted by the committee of the KGS code and now in effect.