• Nuclear Engineering and Technology
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• v.53 no.2
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• pp.455-465
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• 2021

The Molten Salt Reactor (MSR), one of the six advanced reactor types of the 4th generation nuclear energy systems, has many impressive features including economic advantages, inherent safety and nuclear non-proliferation. This paper introduces a system analysis code named TREND, which is developed and used for the steady and transient simulation of MSRs. The TREND code calculates the distributions of pressure, velocity and temperature of single-phase flows by solving the conservation equations of mass, momentum and energy, along with a fluid state equation. Heat structures coupled with the fluid dynamics model is sufficient to meet the demands of modeling MSR system-level thermal-hydraulics. The core power is based on the point reactor neutron kinetics model calculated by the typical Runge-Kutta method. An incremental PID controller is inserted to adjust the operation behaviors. The verification and validation of the TREND code have been carried out in two aspects: detailed code-to-code comparison with established thermal-hydraulic system codes such as RELAP5, and validation with the experimental data from MSRE and the CIET facility (the University of California, Berkeley's Compact Integral Effects Test facility).The results indicate that TREND can be used in analyzing the transient behaviors of MSRs and will be improved by validating with more experimental results with the support of SINAP.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.4
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• pp.687-699
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• 2021

When a vulnerability occurs in a program, it is documented and published through CVE. However, some vulnerabilities do not disclose the details of the vulnerability and in many cases the source code is not published. In the absence of such information, in order to find a vulnerability, you must find the vulnerability at the binary level. This paper aims to find out-of-bounds read vulnerability that occur very frequently among vulnerability. In this paper, we design a memory area using memory access information appearing in binary code. Out-of-bounds Read vulnerability is detected through the designed memory structure. The proposed tool showed better in code coverage and detection efficiency than the existing tools.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.2C
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• pp.219-228
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• 2010

In this paper, performance of RS (Reed-Solomon), turbo and LDPC (low density parity check) code in the binary symmetric erasure channel is investigated. When the average erasure length is reduced, the frequency of short erasures is increased. The RS code shows serious performance degradation in such an environment since decoding is carried out symbol-by-symbol. As the erasure length is increased, however, the RS code shows much improved en-or performance. On the other hand, the message and corresponding parity symbols of the turbo code can be erased at the same time for the long erasures. Accordingly, iterative decoding of the turbo code can not improve error performance any more for such a long erasure. The LDPC code shows little difference in error performance with respect to the variation of the average erasure length due to the virtual interleaving effect. As a result, the LDPC code has much better erasure decoding performance than the RS and turbo code.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4491-4503
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• 2023

This study aimed to verify and validate the transient simulation capability of the hybrid code system RAST-F for fast reactor analysis. For this purpose, control rod (CR) drop experiments involving eight separate CRs and six CR groups in the China Experimental Fast Reactor (CEFR) start-up tests were utilized to simulate the CR drop transient. The RAST-F numerical solution, including the neutron population, time-dependent reactivity, and CR worth, was compared against the measurement values obtained from two out-of-core detectors. Moreover, the time-dependent reactivity and CR worth from RAST-F were verified against the results obtained by the Monte Carlo code Serpent using continuous energy nuclear data. A code-to-code comparison between Serpent and RAST-F showed good agreement in terms of time-dependent reactivity and CR worth. The discrepancy was less than 160 pcm for reactivity and less than 110 pcm for CR worth. RAST-F solution was almost identical to the measurement data in terms of neutron population and reactivity. All the calculated CR worth results agreed with experimental results within two standard deviations of experimental uncertainty for all CRs and CR groups. This work demonstrates that the RAST-F code system can be a potential tool for analyzing time-dependent phenomena in fast reactors.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2363-2369
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• 2016

In this paper, we propose three-dimensional (3D) quick-response (QR) code generation technique using passive 3D integral imaging and computational integral imaging reconstruction technique. In our proposed method, we divide 2D QR code into 4 planes with different reconstruction depths and then we generate 3D QR code using synthetic aperture integral imaging and computational reconstruction. In this 3D QR code generation process, we use integral imaging which is one of 3D imaging technologies. Finally, 3D QR code can be scanned by reconstructing and merging 3D QR codes at 4 different planes with computational reconstruction. Therefore, the security level for QR code scanning may be enhanced when QR code is scanned. To show that our proposed method can improve the security level for QR code scanning, in this paper, we carry out the optical experiments and computational reconstruction. In addition, we show that 3D QR code can be scanned when reconstruction depths are known.

• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.1
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• pp.29-37
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• 2016

We propose vehicular spread spectrum (SS) radar robust to mutual interference using zero correlation zone (ZCZ) code. SS radar schemes have been employed for vehicular radar systems due to their outstanding correlation property. However, this superiority is based on a premise that timing among codes is completely synchronized. In the practical driving environment, timing mismatch among radar signals is inevitable because the radar signals of several vehicles are independently transmitted at each different location and each timing and thus each radar signal is received at different timing. This timing offset is the main cause of orthogonality destruction among codes and thus radar signals from other vehicles become mutual interference. In order to solve this problem, we find out the new property of ZCZ code which maintains the complete orthogonality except to timing offset corresponding to chips (pulses) of multiple of 4 and employ ZCZ code to SS radar systems. Simulation results show the proposed scheme achieve better performance compared with the conventional SS radar scheme using pseudo code or gold code.

• The KIPS Transactions:PartA
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• v.12A no.1 s.91
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• pp.79-86
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• 2005

This paper suggests that sparse code motion algorithm should be used to make the code optimal in the respect of computation and lifetime. This algorithm Is SpCM algorithm, which expand BCM and LCM algorithm. BCM algorithm carries out the optimal code motion computationally and LCM algorithm reduces the register pressure in SpCM algorithm. Generally, code motion algorithm accomplishes the run-time optimal connected with the optimum of computation and the register pressure. Computational cost and consideration of the code size in the register pressure are also added in the paper. The optimum of code motion could be obtained through SpCM algorithm, which considers the code size, in audition to computational optimal and lifetime optimal. The algorithm presented in this paper is the most optimal algorithm in the respect of computation and lifetime, as all the unnecessary code motions are restrained.

• Journal of Ocean Engineering and Technology
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• v.33 no.5
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• pp.400-410
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• 2019

In this study, the numerical code for the 3D nonlinear dynamic analysis of an SLWR (Steel Lazy Wave Riser) was developed using the lumped mass line model in a FORTRAN environment. Because the lumped mass line model is an explicit method, there is no matrix operation. Thus, the numerical algorithm is simple and fast. In the lumped mass line model, the equations of motion for the riser were derived by applying the various forces acting on each node of the line. The applied forces at the node of the riser consisted of the tension, shear force due to the bending moment, gravitational force, buoyancy force, riser/ground contact force, and hydrodynamic force based on the Morison equation. Time integration was carried out using a Runge-Kutta fourth-order method, which is known to be stable and accurate. To validate the accuracy of the developed numerical code, simulations using the commercial software OrcaFlex were carried out simultaneously and compared with the results of the developed numerical code. To understand the nonlinear dynamic characteristics of an SLWR, dynamic simulations of SLWRs excited at the hang-off point and of SLWRs in regular waves were carried out. From the results of these dynamic simulations, the displacements at the maximum bending moments at important points of the design, like the hang-off point, sagging point, hogging points, and touch-down point, were observed and analyzed.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.47-51
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• 2006

The variation of marine accidents and ship's insurances is to be the measurement of assessment concerned effect of importing ISM Code because each kind of ship accident's expenses and compensation for the loss have an effect on the ship's insurance and P&I insurance. Therefore in this study, we had grasped the accomplishment of importing ISM Code, using analysis of the variation of marine accidents and ship's insurances in domestic shipping companies from one year ago to 8 years after importing ISM Code. As the result of analysis, compared with the period of a year before carrying out ISM Code, marine accidents were showed a decrease of about 14.4% at 8th year of importing ISM Code. Also, the insurance had tended downward every year.

• Journal of the Korean Institute of Navigation
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• v.25 no.2
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• pp.195-205
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• 2001

It has been over seven years since Maritime Code of the Peoples Republic of China (hereinafter called the Code) came into force on July 1st 1993. During this period it has played a very important roll in governing Chinas ocean shipping. However, owing to the defects of the Code, many problems have arisen in the performance of the Code, among which is the problem related to delay in delivery. Therefore, it is necessary and inevitable to revise the Code. This study is limited to a rough study on the regulations related to delay in delivery in the Code, such as the definition of delay in delivery, the carriers responsibility for delay in delivery, the carriers exemption from responsibility for delay in delivery, the limitation of responsibility, the procedures of claims for delay in delivery and the difference of the Code from the Korea Commercial Law, the Hague Rules, the Hague-Visby Rules and the Hamburg Rules. Furthermore, some defects in the Code are pointed out and suggestions are provided for the revision of the Code.