• Nuclear Engineering and Technology
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• v.42 no.6
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• pp.636-655
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• 2010

A thermal-hydraulic code, named CUPID, has been being developed for the realistic analysis of transient two-phase flows in nuclear reactor components. The CUPID code development was motivated from very practical needs, including the analyses of a downcomer boiling, a two-phase flow mixing in a pool, and a two-phase flow in a direct vessel injection system. The CUPID code adopts a two-fluid, three-field model for two-phase flows, and the governing equations are solved over unstructured grids with a semi-implicit two-step method. This paper presents an overview of the CUPID code development and assessment strategy. It also presents the code couplings with a system code, MARS, and, a three-dimensional reactor kinetics code, MASTER.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.9
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• pp.1654-1665
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• 2008

This paper presents bit splitting methods to apply multilevel modulation to iterative codes such as turbo code, low density parity check code and turbo product code. Log-likelihood ratio method splits multilevel symbols to soft decision symbols using the received in-phase and quadrature component based on Gaussian approximation. However it is too complicate to calculate and to implement hardware due to exponential and logarithm calculation. Therefore this paper presents Euclidean, MAX, sector and center focusing method to reduce the high complexity of LLR method. Also, this paper proposes optimal soft symbol split method for three kind of iterative codes. Futhermore, 16-APSK modulator method with double ring structure for applying DVB-S2 system and 16-QAM modulator method with lattice structure for T-DMB system are also analyzed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.7
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• pp.857-865
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• 2020

This paper presents a method for code generation of UML sequence diagrams based on message patterns. In the sequence diagrams, it is shown that messages are some types of forms typically. This paper classifies according to type as three patterns, and construct meta-information for code generation analysing structural infomation for each patterns. The meta-message of structural information (MetaMessage) is stored in the MetaMessage datastore and the meta-method information from the MetaMessage is stored in the MetaMethod datastore. And then, the structural information of MetaClass and MetaObject is constructed in each datastore too. For each pattern, this paper presents a method for code generation based on the meta information of message patterns and the syntax of target progamming language. Also, branching and looping that has been seldom handled integratedly in the previous works are handled as same as the basic patterns by classifying the branching pattern and the looping pattern for code generation integratedly.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.2
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• pp.85-96
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• 2008

One of the typical methods to prevent tampering and reverse engineering on executable codes is to encrypt them. This paper proposes a code block cipher method based on key chaining to encrypt the code. The block cipher by key chaining has been known to be inadequate for encrypting the code with control transfer, even though the key chaining has advantage of hiding the keys in blocks and making the individual keys different from block to block. This paper proposes a block transformation and duplication method to apply the block cipher by key chaining to the executable codes with control transfer instructions, and shows the idea works with the MIPS instruction set.

• 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.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.3
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• pp.87-96
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• 2014

Hackers try to achieve their purpose in a variety of ways, such as operating own website and hacking a website. Hackers seize a large amount of private information after they have made a zombie PC by using malicious code to upload the website and it would be used another hacking. Almost detection technique is the use Snort rule. When unknown code and the patterns in IDS/IPS devices are matching on network, it detects unknown code as malicious code. However, if unknown code is not matching, unknown code would be normal and it would attack system. Hackers try to find patterns and make shellcode to avoid patterns. So, new method is needed to detect that kinds of shellcode. In this paper, we proposed a noble method to detect the shellcode by using Shannon's information entropy.

• Advances in Energy Research
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• v.5 no.2
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• pp.91-105
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• 2017

Thermal hydraulic (TH) analysis of nuclear power reactors is utmost important. In this way, the numerical codes that preparing TH data in reactor core are essential. In this paper, a subchannel analysis of a Russian pressurized water reactor (WWER1000) core with enhanced numerical code is carried out. For this, in fluid domain, the mass, axial and lateral momentum and energy conservation equations for desired control volume are solved, numerically. In the solid domain, the cylindrical heat transfer equation for calculation of radial temperature profile in fuel, gap and clad with finite difference and finite element solvers are considered. The dependence of material properties to fuel burnup with Calza-Bini fuel-gap model is implemented. This model is coupled with Isotope Generation and Depletion Code (ORIGEN2.1). The possibility of central hole consideration in fuel pellet is another advantage of this work. In addition, subchannel to subchannel and subchannel to rod connection data in hexagonal fuel assembly geometry could be prepared, automatically. For a demonstration of code capability, the steady state TH analysis of a the WWER1000 core is compromised with Thermal-hydraulic analysis code (COBRA-EN). By thermal hydraulic parameters averaging Fuel Assembly-to-Fuel Assembly method, the one sixth (symmetry) of the Boushehr Nuclear Power Plant (BNPP) core with regular subchannels are modeled. Comparison between the results of the work and COBRA-EN demonstrates some advantages of the presented code. Using the code the thermal modeling of the fuel rods with considering the fission gas generation would be possible. In addition, this code is compatible with neutronic codes for coupling. This method is faster and more accurate for symmetrical simulation of the core with acceptable results.

• Journal of Convergence for Information Technology
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• v.9 no.4
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• pp.14-20
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• 2019

The purpose of this paper is to present a smart QR code recording system and a method of non­storage data delivery that transforms the original data into a form of URL information by encrypting it and encoding the URL information into a QR code so that the QR code can be written and decrypted in a medium without storing the original data. The method of the study was presented by the prior art study and the literature research. Analysis results show that the system is built on the online administration server. The data input signal matching secret code is stored in DB, the QR code generation command converts input data from the password DB to the password information combined into the subordinate locator of the admin server's domain name, URL code. Therefore, the smart QR method of data management (recording and providing) indicates that there are no limitations in the ease and space of use or obstacles to capacity use.

• Journal of Radiation Industry
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• v.17 no.1
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• pp.83-92
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• 2023

When assessing the risk of radioactive wastes transportation on land, computer codes such as RADTRAN and RISKIND are used as deterministic methods. Transportation risk assessment using the deterministic method requires a relatively short assessment time. On the other hand, transportation risk assessment using the probabilistic method requires a relatively long assessment time, but produces more reliable results. Therefore, a study is needed to evaluate the exposure dose using a deterministic method that can be evaluated relatively quickly, and to compare and analyze the exposure dose result using a probabilistic method. The purpose of this study is to evaluate the exposure dose during transportation of radioactive wastes using deterministic and probabilistic methods, and to compare and analyze them. For this purpose, the main exposure factors were selected and various exposure situations were set. The distance between the radioactive waste and the receptor, the size of the package, and the speed of vehicle were selected as the main exposure factors. The exposure situation was largely divided into when the radioactive wastes were stationary and when they were passing. And the dose (rate) model of the deterministic overland transportation risk assessment computer code was analyzed. Finally, the deterministic method of the RADTRAN computer code and the RISKIND computer code and the probabilistic method of the MCNP 6 computer code were used to evaluate the exposure dose in various exposure situations during transportation of radioactive wastes. Then we compared and analyzed them. As a result of the evaluation, the tendency of the exposure dose (rate) was similar when the radioactive wastes were stationary and passing. For the same situation, the evaluation results of the RADTRAN computer code were generally more conservative than the results of the RISKIND computer code and the MCNP 6 computer code. The evaluation results of the RISKIND computer code and the MCNP 6 computer code were relatively similar. The results of this study are expected to be used as basic data for establishing the radioactive wastes transportation risk assessment system in Korea in the future.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.239-242
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• 2001

영상에 워터마크를 삽입하는 것을 통신채널의 입장에서 해석한다면 워터마크는 신호로, 영상은 잡음으로 모델링이 가능하다. 따라서 이러한 잡음 속에서 신호에 대한 에러를 최소화하는 것이 워터마크의 추출을 최대화하는 것이라 할 수 있다. 통상적으로 Error Correction Code는 에러가 많은 통신채널에서 많이 이용되기 때문에 워터마킹 방법에서도 효과를 기대할 수 있다. 본 논문에서는 DCT 기반의 구간화 워터마킹 방법에 Turbo code를 이용하여 강인성 면에서의 향상된 성능을 실험 결과로 보이며, Turbo code의 해밍거리를 이용하여 워터마킹의 보다 효율적인 검출 방법을 제안한다.