• Journal of Information Processing Systems
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• v.19 no.2
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• pp.139-148
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• 2023

Current food-traceability platforms suffer from problems such as inconsistent traceability standards, a lack of public credibility, and slow access to data. In this work, a combined code and identification method was designed that can achieve more secure product traceability using the dual anti-counterfeiting technology of a QR code and a hidden code. When the QR code is blurry, the hidden code can still be used to effectively identify food information. Based on this combined code, a food-safety traceability platform was developed. The platform follows unified encoding standards and provides standardized interfaces. Based on this innovation, the platform not only can serve individual food-traceability systems development, but also connect existing traceability systems. These will help to solve the problems such as non-standard traceability content, inconsistent processes, and incompatible system software. The experimental results show that the combined code has higher accuracy. The food-safety traceability platform based on the combined code improves the safety of the traceability process and the integrity of the traceability information. The innovation of this paper is invoking the combined code united the QR code's rapidity and the hidden code's reliability, developing a platform that uses a unified coding standard and provides a standardized interface to resolve the differences between multi-food-traceability systems. Among similar systems, it is the only one that has been connected to the national QR code identification platform. The project has made profits and has significant economic and social benefits.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.9
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• pp.12-17
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• 2016

In the holographic data storage system (HDSS), the data regarding the volume of a storage medium are recorded and read by the page, and the transmission rate and storage capacity can be increased because of two-dimensional, page-oriented data processing; furthermore, the multi-level HDSS can store more than one bit per pixel. For this same reason, however, and unlike conventional data-storage systems, the HDSS is hampered by two-dimensional (2D) intersymbol interference (ISI) and interpage interference (IPI). Progress regarding the published papers on 2D ISI, which is more severe in the multi-level HDSS, continues; however, mitigation of both 2D ISI and IPI in terms of the multi-level HDSS has not yet been studied. In this paper, we therefore propose a 4-level balanced-modulation code that simultaneously mitigates 2D ISI and IPI.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1B
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• pp.1-7
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• 2000

Generally, one-dimensional fiber optic code-division multiple-access(CDMA) system is encoded and decoded using optical orthogonal codes(OOC’s), where two-dimensional fiber optic CDMA system uses optical orthogonal signature pattern codes(OOSPC’s) for parallel data link process. The OOSPC’s should have good autocorrelation and cross-correlation properties. However, if timing information or synchronization of OOSPC’s can be obtained by other means, the property of autocorrelation may not be restricted and we can increase the number of pattern codes. In this paper we introduce the fiber optic CDMA system for parallel transmission of two-dimensional data and investigate methods of generation of two-dimensional pattern codes. The probability density function of interference noise is calculated in interfering OOSPC’s of the users and the corresponding bit error rate is derived.. We compare each OOSPC’s by plotting bit error rate versus threshold values and the number of simultaneous users, from the result, we propose the optimal OOSPC’s conditions for the parallel transmission of two-dimensional data.

• Journal of Korea Soil Environment Society
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• v.1 no.1
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• pp.89-102
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• 1996

An integrated model is presented to describe underground flow and mass transport, using a multicomponent multiphase approach. The comprehensive governing equation is derived considering mass and force balances of chemical species over four phases(water, oil, air, and soil) in a schematic elementary volume. Compact and systemati notations of relevant variables and equations are introduced to facilitate the inclusion of complex migration and transformation processes, and variable spatial dimensions. The resulting nonlinear system is solved by a multidimensional finite element code. The developed code with dynamic array allocation, is sufficiently flexible to work across a wide spectrum of computers, including an IBM ES 9000/900 vector facility, SP2 cluster machine, Unix workstations and PCs, for one-, two and three-dimensional problems. To reduce the computation time and storage requirements, the system equations are decoupled and solved using a banded global matrix solver, with the vector and parallel processing on the IBM 9000. To avoide the numerical oscillations of the nonlinear problems in the case of convective dominant transport, the techniques of upstream weighting, mass lumping, and elementary-wise parameter evaluation are applied. The instability and convergence criteria of the nonlinear problems are studied for the one-dimensional analogue of FEM and FDM. Modeling capacity is presented in the simulation of three dimensional composite multiphase TCE migration. Comprehesive simulation feature of the code is presented in a companion paper of this issue for the specific groundwater or flow and contamination problems.

• Journal of Energy Engineering
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• v.23 no.4
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• pp.112-122
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• 2014

A main steam line break (MSLB) test at the ATLAS facility was simulated using the best-estimate thermal-hydraulic system code, MARS-KS. This has been performed as an activity at the third domestic standard problem for code benchmark (DSP-03) that has been organized by Korea Atomic Energy Research Institute (KAERI). The results of the MSLB experiment and the MARS input data prepared for the previous DSP-02 using the ATLAS facility were provided to participants. The preliminary MSLB simulation using the base input data, however, showed unphysical results in the primary-to-secondary heat transfer. To resolve the problems, some improvements were implemented in the MARS input modelling. These include the use of fine meshes for the bottom region of the steam generator secondary side and proper thermal-hydraulics calculation options. Other input model improvements in the heat loss and the flow restrictor models were also made and the results were investigated in detail. From the results of simulations, the limitations and further improvement areas of the MARS code were identified.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11A
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• pp.1073-1077
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• 2010

This paper proposes a new 4-dimensional(4D) constellation-rotation(CR) method which obtains diversity gain of 4 under Rayleigh fading channels. The proposed scheme uses two consecutive CR operations for the constellation of QAM signals unlike a conventional 2-dimensional(2D) CR method using only one CR operation. The computer simulation results show that the new method outperforms the conventional one even more as both the channel code rate and the erasure ratio increase. In a point of system flexibility, the proposed scheme has a great advantage since the conventional 2D CR scheme can be simply implemented by only changing rotation angle values used in the proposed scheme.

• Nuclear Engineering and Technology
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• v.38 no.6
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• pp.551-560
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• 2006

In this study, a controller for a nuclear reactor power is designed. The reactor is modeled using the three dimensional reactor design code MASTER. From the relationship of the input and output of the reactor code, a reactor dynamic model is derived by the system identification method. This model is more realistic than the one based on mathematical theories. With this model, a robust controller is designed by the extended frequency response method. As this method has the same theoretical background as the classical method, all of the existing design techniques of the classical method can be used directly. Furthermore, by introducing the real part of a Laplacian operator into the frequency response, the control design specification can be considered at the initial stage of design. The designed controller is simple, and gives a sufficient robustness with good performance.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05a
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• pp.179-184
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• 1996

Power density distribution and criticality of a pressurized water reactor are calculated with a Monte Carlo calculation using the MCNP code. The MCNP model is based on one-eighth core symmetry. Individual fuel assemblies are modeled with fullscope three dimensional description except grid spacer. The fuel rod is divided into eight axial segments. Core internals above and below the active fuel region is represented as coolant. After 400 cycle calculations, the system converges to a k value of 1.09151$\pm$0.00066. Fission reaction rate in each rod is also calculated to use as the source term in pressure vessel fluence calculation.

• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1339-1348
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• 2018

The aim of this paper is to determine neutronic performances of the light water reactor (LWR) spent fuel mixed with fertile thorium fuel in a FFHR. Time dependent three dimensional calculations for major technical data, such as blanket energy multiplication, tritium breeding ratio, cumulative fissile fuel enrichment and burnup have been performed by using Monte Carlo Neutron-Particle Transport code MCNP5 1.4, coupled with a novel interface code MCNPAS, which is developed by our research group. A self-sustaining tritium breeding ratio (TBR>1.05) has been kept throughout the calculations. The study has shown that the fissile fuel quality will be improved in the course of the transmutation of the LWR spent in the FFHR. The latter has gained the reusable fuel enrichment level conventional LWRs between one and two years. Furthermore, LWR spent fuel - thorium mixture provides higher burn-up values than in light water reactors.

• Nuclear Engineering and Technology
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• v.53 no.7
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• pp.2221-2228
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• 2021

One-dimensional oxygen transport relation is indispensable to study the oxygen distribution in the LBE-cooled system with an oxygen control device. In this paper, a numerical research is carried out to study the oxygen transport characteristics in a gas-phase oxygen control device, including the static case and dynamic case. The model of static oxygen control is based on the two-phase VOF model and the results agree well with the theoretical expectation. The model of dynamic oxygen control is simplified and the gas-liquid interface is treated as a free surface boundary with a constant oxygen concentration. The influences of the inlet and interface oxygen concentration, mass flow rate, temperature, and the inlet pipe location on the mass transfer characteristics are discussed. Based on the results, an oxygen mass transport relation considering the temperature dependence and velocity dependence separately is obtained. The relation can be used in a one-dimensional system analysis code to predict the oxygen provided by the oxygen control device, which is an important part of the integral oxygen mass transfer models.