• Nuclear Engineering and Technology
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• v.55 no.7
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• pp.2712-2722
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• 2023

For an accurate and efficient time-dependent Monte Carlo (TDMC) neutron transport analysis, several advanced methods are newly developed and implemented in the Seoul National University Monte Carlo code, McCARD. For an efficient control of the neutron population, a dynamic weight window method is devised to adjust the weight bounds of the implicit capture in the time bin-by-bin TDMC simulations. A moving geometry module is developed to model a continuous insertion or withdrawal of a control rod. Especially, the history-based batch method for the TDMC calculations is developed to predict the unbiased variance of a bin-wise mean estimate. The developed methods are verified for three-dimensional problems in the C5G7-TD benchmark, showing good agreements with results from a deterministic neutron transport analysis code, nTRACER, within the statistical uncertainty bounds. In addition, the TDMC analysis capability implemented in McCARD is demonstrated to search the optimum detector positions for the pulsed-neutron-source experiments in the Kyoto University Critical Assembly and AGN201K.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.1
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• pp.15-21
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• 2010

This paper proposes the multimedia fingerprinting code insertion algorithm when video content is distributed in P2P environment, and designs the collusion codebook SRP(Small RISC Processor) embedded system for the collusion attack prevention. In the implemented system, it is detecting the fingerprinting code inserted in the video content of the client user in which it requests an upload to the web server and in which if it is certified content then transmitted to the streaming server then the implemented system allowed to distribute in P2P network. On the contrary, if it detects the collusion code, than the implemented system blocks to transmit the video content to the streaming server and discontinues to distribute in P2P network. And also it traces the colluders who generate the collusion code and participates in the collusion attack. The collusion code of the averaging attack is generated with 10% of BIBD code v. Based on the generated collusion code, the codebook is designed. As a result, when the insert quantity of the fingerprinting code is 0.15% upper in bitplane 0~3 of the Y(luminance) element of I-frame at the video compression of ASF for a streaming service and MP4 for an offline offer of video content, the correlation coefficient of the inserted original code and the detected code is above 0.15. At the correlation coefficient is above 0.1 then the detection ratio of the collusion code is 38%, and is above 0.2 then the trace ratio of the colluder is 20%.

• Journal of the Korea Society of Computer and Information
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• v.12 no.2 s.46
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• pp.29-36
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• 2007

In the Java a profiler interface such as JVM TI is provided for communication between a Java virtual machine and a profiler. The JVM TI specification, however does not require an implementation of a profiler interface. Consequently the JVM without an implementation of a profiler interface cannot use a profiler with the JVM TI. For solving the problem, we propose a technique which analyzes heap usage without a profiler interface. This technique inserts codes to extract heap usage into source files in the Java. We implemented a code inserter to verify the proposed technique. We experimented with Java programs that are frequently used and opened. the experimental result presents the number of created objects. the maximum number of allocated objects, and the used pattern of the objects.

• Journal of KIISE:Information Networking
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• v.29 no.6
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• pp.663-673
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• 2002

Server-side anti-viruses are useful to protect their domains, because they can detect malicious codes at the gateway of their domains. In prevailing local network, all clients cannot be perfectly controlled by domain administrators, so server-side inspection, for example in e-mail server, is used as an efficient technique of detecting mobile malicious codes. However, current server-side anti-virus systems perform only signature-based detection for known malicious codes, simple filtering, and file name modification. One of the main reasons that they don't have detection features, for unknown malicious codes, is that activity monitoring technique is unavailable for server machines. In this paper, we propose a detection technique that is executed at the server, but it can monitor activities at the clients without any anti-virus features. we describe its implementation.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.10
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• pp.11-18
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• 1998

A binary line code, called MB46d, is designed by use of the BUDA(Binary Unit DSV and ASV) cell concept to retain the property of being runlength limited, DC tree, and with a power spectral null at the Nyquist frequency. This new code is a stateless line code with a simple encoding and a decoding rule and enables efficient error monitoring. The power spectrum and the eye pattern of the new line code are simulated for a minimum-bandwidth digital transmission system where the sinc function is used as a basic pulse. The obtained power null at the Nyquist frequency is wide enough to enable easy band-limiting as well as secure insertion of a clock pilot where necessary. The eye is also substantially wide to tolerate a fair amount of timing jitter in the receiver.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.1
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• pp.31-40
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• 2022

This paper proposes an augmented QSBC(Quantum Short-Block Code) that preserves the function of the existing QSBC and adds a single bit-flip error correction function due to Pauli X and Y errors. The augmented QSBC provides the diagnosis and automatic correction of a single Pauli X error by inserting additional auxiliary qubits and Toffoli gates as many as the number of information words into the existing QSBC. In this paper, the general expansion method of the augmented QSBC using seed vector and the realization method of the Toffoli gate of the single bit-flip error automatic correction function reflecting the scalability are also presented. The augmented QSBC proposed in this paper has a trade-off with a coding rate of at least 1/3 and at most 1/2 due to the insertion of auxiliary qubits.

• Nuclear Engineering and Technology
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• v.49 no.4
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• pp.700-709
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• 2017

This work looks at the effect of changes in kinetic parameters on simultaneous reactivity insertions and beam tube flooding in a typical material testing reactor-type research reactor with low enriched high density ($U_3Si_2-Al$) fuel. Using a modified PARET code, various ramp reactivity insertions (from $0.1/0.5 s to $1.3/0.5 s) plus beam tube flooding ($0.5/0.25 s) accidents under uncontrolled conditions were analyzed to find their effects on peak power, net reactivity, and temperature. Then, the effects of changes in kinetic parameters including the Doppler coefficient, prompt neutron lifetime, and delayed neutron fractions on simultaneous reactivity insertion and beam tube flooding accidents were analyzed. Results show that the power peak values are significantly sensitive to the Doppler coefficient of the system in coupled accidents. The material testing reactor-type system under such a coupled accident is not very sensitive to changes in the prompt neutron life time; the core under such a coupled transient is not very sensitive to changes in the effective delayed neutron fraction.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.1
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• pp.14-24
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• 2017

In this paper, we propose a new EIM(erasure insertion method) based on the average-minimal-noise-power for HOM(higher order modulation) over AWGN(additive white Gaussian noise) under PBJ(partial-band jamming). Then we design SFH/SS(slow-frequency-hopping spread-spectrum) system by applying this method and formulate the PER(packet error rate) of the system. Based on this formula, we propose a new method to set the optimal threshold of the EIM and verify it at the designed 16-QAM SFH/SS system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.11
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• pp.6849-6855
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• 2014

Recently, with the increasing use of smart phones, security issues, such as safety and reliability of the use of the Android application has become a topic to provide services in various forms. An Android application is performed using several important files in the form of an apk file. On the other hand, they may be subject to unauthorized use, such as the loss of rights and privileges due to the insertion of malicious source code of these apk files. This paper examines the Android environment to study ways to define the threats related to the unauthorized use of the application source code, and based on the results of the analysis, to prevent unauthorized use of the application source code. In this paper, a system is provided using a third body to prevent and detect applications that have been counterfeited or forged illegally and installed on Android devices. The application provides services to existing systems that are configured with only the service server that provides users and applications general, This paper proposes the use of a trusted third party for user registration and to verify the integrity of the application, add an institution, and provide a safe application.

• The Transactions of the Korea Information Processing Society
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• v.1 no.4
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• pp.479-489
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• 1994

At the present time, it is an important problem that we are to select a transmission line code for the very-high speed optical transmission system which can confidentially transfer the original information signal sequence efficiently, as it is to be the large capacity and the economization for the optical digital transmission system to transfer the information signal sequence at the very-high speed. Therefore, this paper is to select first the proper transmission line codes for the high speed(more than Mb/s) optical transmission system of the proposed two-level unipolar transmission line codes up to date, and to decide a mBIZ (m Binary with One Zero insertion) code as an optimal transmission line code for the very-high speed optical transmission system, resulting from analyzing the performance at the requirements of the transmission line code, such as the maximum consecutive identical digits, the transmission delay time, the increasing rate of clock, the mark rate, the circuit complexity, the supervision of transmission line error, and power spectrum among the selected transmission line codes.