• Information and Communications Magazine
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• v.32 no.6
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• pp.39-49
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• 2015

In cryptographic applications, the key protection is either knowledge-based (passwords) or possession-based (tamper-proof device). Unfortunately, both approaches are easily forgotten or stolen, thus introducing various key management issues. By incorporating biometrics technologies which utilize the uniqueness of personal characteristics, the security of cryptosystems could be strengthened as authentication now requires the presence of the user. Biometric Cryptosystem (BC) encompasses the design of cryptographic keys protection methods by incorporating biometrics. BC involves either key-biometrics binding or direct key generation from biometrics. However, the wide acceptance and deployment of BC solutions are constrained by the fuzziness related with biometric data. Hence, error correction codes (ECCs) should be adopted to ensure that fuzziness of biometric data can be alleviated. In this overview paper, we present such ECC solutions used in various BCs. We also delineate on the important facts to be considered when choosing appropriate ECCs for a particular biometric based solution from accuracy performance and security perspectives.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.313-316
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• 2005

In the recent design of high ductile fiber-reinforced cementitious composite ECC, which exhibits tensile strain-hardening behavior in the hardened state, optimizing both processing mechanical properties for specific applications is critical. This study introduced a method to develop useful ECCs in field, which possess the different fluid properties to facilitate diverse types of processing (i.e., self-consolidating or spray processing). Control of rheological modulation was regarded as a key factor to allow the performance of the desired processing, while retaining the ductile material properties. To control the rheological properties of the composite, we first determined basic ECC compositon, which is based on micromechanics and steady-state cracking theory. The stability and consequent viscosity of suspensions were, then, mediated by optimizing dosages of chemical and mineral admixtures. The rheological properties altered by this approach were revealed to be effective in obtaining ECC hardened properties, allowing us to readily achieve the desired function of the fresh ECC.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.3
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• pp.389-395
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• 2011

Since Elliptic Curve Cryptosystems(ECCs) support the same security as RSA cryptosystem and ElGamal cryptosystem with 1/6 size key, ECCs are the most efficient to smart cards, cellular phone and small-size computers restricted by high memory capacity and power of process. In this paper, we explicitly explain methods for finite fields operations used in ECC, and then construct some composite fields over finite fields which are secure under Weil's decent attack and maximize the speed of operations. Lastly, we propose a fast multiplier over our composite fields.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.451-452
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• 2004

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.431-432
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• 2004

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.11a
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• pp.555-556
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• 2018

• Nuclear Engineering and Technology
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• v.26 no.3
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• pp.355-366
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• 1994

The USNRC issued a revised ECCS rule that allows the use of best estimate computer codes for safety analysis. The rule also requires an estimation of uncertainty in calculated system response when applying the best estimate computer codes. A practical realistic evaluation methodology to evaluate the ECCS performance that satisfies the requirements of the ECCS rule has been developed and this paper describes the application of new realistic evaluation methodology to large break LOCA for, the demonstration of the new methodology. The computer code RELAP5/MOD3/KAERI, which was improved from RELAP5/MOD3.1, was used as the best estimate code in the application. The uncertainty of the code was evaluated by assessing several separate and integral effect tests, and for the application to actual plant Kori 3 & 4 was selected as the reference plant. Response surfaces for blowdown and reflood PCTs were generated from the results of the sensitivity analyses and probability distribution functions were established by random sampling or Monte-Carlo method for each response surface. Final uncertainties were quantified at 95% probability level and safety margins for large break LOCA were discussed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.12
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• pp.654-662
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• 2017

When emergency core cooling system (ECCS) is operated during loss of coolant accident (LOCA) in a pressurized water reactor (PWR), pressurized thermal shock (PTS) phenomenon can occur as cooling water is injected into a cold leg, mixed with hot primary coolant, and then entrained into a reactor vessel. Insufficient flow mixing may cause temperature stratification and steam condensation. In addition, flow vibration may cause thermal stresses in surrounding structures. This will reduce the life of the reactor vessel. Due to the importance of PTS phenomenon, in this study, calculation was performed for Test 1 among six types of OECD/NEA ROSA tests with ANSYS CFX R.17. Predicted results were then compared to measured data. Additionally, because temperature difference between the hot coolant at the inlet of the cold leg and the cold cooling water at the inlet of the ECCS injection line is 200 K or more, buoyancy force due to density difference might have significant effect on thermal-hydraulic characteristics of flow. Therefore, in this study, the necessity to include buoyancy force term in governing equations for accurate prediction of single phase thermal stratification in both cold legs and downcomer by ECCS injection was numerically studied.

• Proceedings of the Korean Nuclear Society Conference
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• 2002.10a
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• pp.169-169
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• 2002

• Proceedings of the Korean Nuclear Society Conference
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• 2003.10a
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• pp.157-157
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• 2003