• Nuclear Engineering and Technology
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• 제52권12호
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• pp.2760-2770
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• 2020

A model for calculation of fuel temperature profile using binary gas mixture of Helium and Xenon for gap gas conductance is proposed here. In this model, the temperature profile of a fuel pencil from fuel centreline to fuel surface has been calculated by taking into account the dilution of Helium gas filled during fuel manufacturing due to accumulation of fission gas Xenon. In this model an explicit calculation of gap gas conductance of binary gas mixture of Helium and Xenon has been carried out. A computer code Fuel Characteristics Calculator (FCCAL) is developed for the model. The phenomena modelled by FCCAL takes into account heat conduction through the fuel pellet, heat transfer from pellet surface to the cladding through the gap gas and heat transfer from cladding to coolant. The binary noble gas mixture model used in FCCAL is an improvement over the parametric model of Lassmann and Pazdera. The results obtained from the code FCCAL is used for fuel temperature calculation in 3-D neutron diffusion solver for the coolant outlet temperature of the core at steady operation at full power. It is found that there is an improvement in calculation time without compromising accuracy with FCCAL.

• 한국통신학회논문지
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• 제38B권5호
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• pp.377-384
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• 2013

비밀번호 기반의 사용자 인증은 동일한 비밀번호를 반복 사용하므로 보안이 취약하여 OTP(One-Time Password)가 도입되었다. 하지만 보안이 강화된 OTP를 서버와 동기된 모바일 기기에서 생성하여 PC에 입력하는 경우 PC가 악성코드에 감염되어 있으면 해커가 사용자 계정과 비밀번호 그리고 OTP값을 해킹할 수 있다. 본 논문에서는 OTP값 유출에 따른 보안 취약성을 해소하기 위해 사용자는 계정과 비밀번호를 PC에 입력하여 서버인증을 수행하고, PC 화면에 출력된 QR코드를 모바일 기기에서 스캔하여 OTP값을 직접 서버로 전송함으로써 정보 유출에 따른 해킹을 방지하고 PC에 OTP값을 입력하는 불편함을 줄이는 새로운 이중 인증 방식인 DTOTP를 제안한다. 시스템은 이중 전송을 통해 PC인증 방식의 OTP 보다 향상된 보안성을 제공하면서 기존 OTP 알고리즘을 그대로 사용할 수 있어 구현이 용이하며 은행, 포털 및 게임 서비스 등에 안전하게 활용할 수 있다.

• 한국중재학회지:중재연구
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• 제31권2호
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• pp.23-46
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• 2021

Sports disputes have specific characteristics compared to disputes that arise in the field of commerce. One particularity is the judicial system in which the CAS plays a key role as the International Supreme Court for sports-related matters. The CAS Code applies whenever the parties agree to submit a sports-related dispute to the CAS(Art. R27). Once the parties to the arbitration agreement have decided that the CAS Code should govern their proceedings. The parties' autonomy is, however, limited to the provisions of the CAS Code that provide for such a corresponding autonomy. The application of the mandatory rules contained in the CAS Code cannot be excluded. In CAS appeals arbitration proceedings, the Panel shall decide the dispute according to the applicable sports regulations and, subsidiarily, to the rules of law chosen by the parties(Art. R58). In international sports disputes, the uniform application and interpretation of the relevant regulations are essential. Therefore, Art. R58 should be applied as a mandatory rule without any changes. Regulations of the sports organizations are to be qualified as valid rules of law. CAS panels may also apply the so-called lex sportiva to the merits before considering statutory provisions of national jurisdictions. In this way, the specificities in (international) sports disputes can be taken into account without the need to further examine the application of national legal standards.

• 에너지공학
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• 제13권3호
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• pp.181-190
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• 2004

Computational models for analyzing the in-reactor behavior of metallic fuel pins under transient conditions in liquid-metal reactors are developed and implemented in the TRAMAC (TRAnsient thermo-Mechanical Analysis Code) for a metal fuel rod under transient operation conditions. Not only the basic models for a fuel rod performance but also some sub-models used for transient condition are installed in TRAMAC. Among the models, a fission gas release model, which takes the multi-bubble size distribution into account to characterize the lenticular bubble shape and the saturation condition on the grain boundary and the cladding deformation model have been developed based mainly on the existing models in the MAC-SIS code. Finally, cladding strains are calculated from the amount of thermal creep, irradiation creep, and irradiation swelling. The cladding strain model in TRAMAC predicts well the absolute magnitudes and gen-eral trends of their predictions compared with those of experimental data. TRAMAC results for the FH-1,2,6 pins are more conservative than experimental data and relatively reasonable than those of FPIN2 code. From the calculation results of TRAMAC, it is apparent that the code is capable of predicting fission gas release, and cladding deformation for LMR metal fuel finder transient operation conditions. The results show that in general, the predictions of TRAMAC agree well with the available irradiation data.

• Structural Engineering and Mechanics
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• 제89권4호
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• pp.363-374
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• 2024

Significant changes have been made to estimate the punching shear capacity for edge column-slab joints in the latest editions of most current codes. The revised equations account for axial forces as well as moments conveyed to columns from slabs, which have a substantial impact on the punching resistance of such joints. Many key design parameters, such as reinforcement-ratio, concrete strength, size-effect, and critical-section perimeter, were treated differently or even ignored in various code provisions. Consequently, wide ranges of predicted punching shear strength were detected by applying different code formulas. Therefore, it is essential to assess the various current Codes' design-equations. Because of the similarity in estimated outcomes, only the ACI, EC, and SNiP are used in this study to cover a wide range of estimation ranges from highly conservative to unconservative. This paper is devoted to analyzing the techniques in these code provisions, comparing the estimated punching resistance with available experimental data, and finally developing efficient models predicting the punching capacity of edge column-slab connections. 63 samples from past investigations were chosen for validation. To appropriately predict the punching shear, newly updated equations for ACI and SNiP are provided based on nonlinear regression analysis. The proposed equations'results match the experimental data quite well.

• 한국전산유체공학회지
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• 제20권2호
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• pp.23-36
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• 2015

The $2^{nd}$ generation ice accretion analysis program has been developed and validated for various icing conditions. The essential feature of the $2^{nd}$ generation code lies in its capability of handling general 3-D geometry and improved accuracy. The entire velocity fields are obtained based on Navier-Stokes equations in order to take the massively separated flow field into account. Unlike $1^{st}$ generation code, the droplet trajectories are calculated using Eulerian approach, which is adopted to yield appropriate collection efficiency even in the shadow region. For improved thermodynamic analysis on the surfaces, water film model and modified Messinger model are newly included in the present analysis. The ice shape for a given time step is obtained by considering the exact amount of ice accreted on the surface. Each module of the icing analysis code has been seamlessly integrated on the OpenFOAM platform. The developed code was validated against available experimental data for 2D airfoils and 3D DLR-F4. Due to the lack of experimental data, the computed results of DLR-F4 were compared with those obtained from FENSAP-ICE, which is state-of-the-art 3D icing analysis code. It was clearly shown that the present code produces comparable results to those of FENSAP-ICE, in terms of prediction accuracy and the capability of handling general 3-D geometries.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall
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• pp.273-280
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• 1999

The base shear and the veritcal distribution of shears along the height of a building are two fundamental measures that define the design seismic load. But the method specified in Korean building code does not give an appropriate distribution for buildings of tall or longer period because it roughly account for the contributions of the higher modes. several methods to give a better distribution of seismic forces have been proposed. But they have not been introduced into the seismic codes yet probably because they cannot solve all the above-mentioned problems. This paper deals with the distribution of lateral seismic forces along the height of a building to account for the contribution of the higher modes. After reviewing some existing distributions in seismic codes and literatures moment-resisting frames with various stories were studied by modal analysis for a wide range of fundamental period and the stiffness ratio of the buiding. As a result of the analysis a new expression for the distribution of seismic forces is proposed and compared with those of some codes and dynamic analysis.

• 한국해양공학회지
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• 제27권1호
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• pp.1-8
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• 2013

This paper presents the results of experimental and numerical research on the slamming phenomenon. Two experimental techniques were proposed in this study. The traditional free drop tests were carried out. However, the free drop tests done in this study using an LM guide showed excellent repeatability, unlike those of other researchers. The coefficients of variation for the drop test done in this experiment were less than 0.1. The other experimental technique proposed in this study was a novel concept that used a pneumatic cylinder. The pneumatic cylinder could accelerate the specimen over a very short distance from the free surface. As a result, high rates of repeatability were achieved. In the numerical study, the development of in-house code and utilization of commercial code were carried out. The in-house code developed was based on the boundary element method. It is a potential code. This was mostly applied to the computation of the wedge entry problem. The commercial code utilized was FLUENT. Most of the previous slamming research was done under the assumption of a constant body velocity all through the impact process, which is not realistic at all. However, the interaction of a fluid and body were taken into account by employing a user-defined function in this study. The experimental and numerical results were compared. The in-house code based on BEM showed better agreement than that of the FLUENT computation when it cames to the wedge computation. However, the FLUENT proved that it could deal with a very complex geometry while BEM could not. The proposed experimental and numerical procedures were shown to be very promising tools for dealing with slamming problems.

• Nuclear Engineering and Technology
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• 제41권9호
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• pp.1143-1156
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• 2009

The SPACE code that is based on a multi-dimensional two-fluid, three-field model is under development for licensing purposes of pressurized water reactors in Korea. Among the participating research and industrial organizations, KAERI is in charge of developing the physical models and correlation packages for the constitutive equations. This paper introduces a developed wall-to-fluid heat transfer package for the SPACE code. The wall-to-fluid heat transfer package consists of twelve heat transfer subregions. For each sub-region, the models in the existing safety analysis codes and the leading models in literature have been peer reviewed in order to determine the best models which can easily be applicable to the SPACE code. Hence a wall-to-fluid heat transfer region selection map has been developed according to the non-condensable gas quality, void fraction, degree of subcooling, and wall temperature. Furthermore, a partitioning methodology which can take into account the split heat flux to the continuous liquid, entrained droplet, and vapor fields is proposed to comply fully with the three-field formulation of the SPACE code. The developed wall-to-fluid heat transfer package has been pre-tested by varying the independent parameters within the application range of the selected correlations. The smoothness between two adjacent heat transfer regimes has also been investigated. More detailed verification work on the developed wall-to-fluid heat transfer package will be carried out when the coupling of a hydraulic solver with the constitutive equations is brought to completion.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1998년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
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• pp.20-27
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• 1998

In the current seismic design codes design earthquake is usually defined as the earthquake with the 90 percent probability of not being exceeded in the life time of a structure which is assumed as 50 years equivalent to the earthquake with 475 year recurrence period. However the life time of tall building structures may be much longer than 50 yers. The current seismic design code requires the modal analysis or dynamic time history analysis for the buildings with the height exceeding a certain height limit. The objective of this study is to collect the earthquake ground motion(EQGM) which can be used for dynamic time history analysis for tall buildings. For this purpose linear elastic design response spectrum (LEDRS) in the code is scaled to account for the recurrence period of the design earthquake. The earthquake ground motions which has been recorded are calibrated to fit the scaled LEDRS. The set of calibrated EQGM can be treated as design EQGM for the design of tall building with longer lifetime than ordinary building.