• Current Optics and Photonics
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• 제7권4호
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• pp.463-470
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• 2023

Hydroxygraphene as a kind of functionalized graphene has important applications in composite, photoelectric and biological materials. In the present study, THz and microfluidic technologies were implemented to study the THz transmission characteristics of hydroxygraphene with different concentrations and residence times in magnetic and electric fields. The results show that the THz transmission intensity decreases with the increase in sample concentration and duration of an applied electric field, while it increases by staying longer in the magnetic field. The phenomenon is analyzed and explained in terms of hydrogen bond, conductivity and scattering characteristics. The results establish a foundation for future research on the THz absorption characteristics of liquid graphene based on microfluidic technology in different external environments. It also provides technical support for the application and development of graphene in THz devices.

• 정보보호학회논문지
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• 제28권5호
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• pp.1059-1070
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• 2018

블록암호 Zorro는 AES와 비슷한 연산과정을 거치나 S-box 개수를 줄여 부채널 공격에 대비한 마스킹을 구현 비용을 줄일 수 있게 설계되었다. 하지만 마스터키를 라운드키로 그대로 사용하기 때문에 연관키 차분공격 관점에서 취약하다. 본 논문에서는 Zorro의 연관키 차분특성을 이용해 키 복구 공격을 보인다. 또한 안전성이 증명된 12가지의 PGV 모델을 Zorro를 기반으로 할 때 블록암호의 연관키 차분 특성이 해시함수 충돌쌍 공격에 어떻게 활용될 수 있는지 설명하고 실제 충돌쌍을 제시한다.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1436-1445
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• 2021

To obtain the dynamic characteristics of reactor secondary circuit under transient conditions, the system analysis program was developed in this study, where dynamic models of secondary circuit were established. The heat transfer process and the mechanical energy transfer process are modularized. Models of main equipment were built, including main turbine, condenser, steam pipe and feedwater system. The established models were verified by design value. The simulation of the secondary circuit system was conducted based on the verified models. The system response and characteristics were investigated based on the parameter transients under emergency shutdown and overload. Various operating conditions like turbine emergency shutdown and overspeed, condenser high water level, ejector failures were studied. The secondary circuit system ensures sufficient design margin to withstand the pressure and flow fluctuations. The adjustment of exhaust valve group could maintain the system pressure within a safe range, at the expense of steam quality. The condenser could rapidly take out most heat to avoid overpressure.

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.403-408
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• 2005

Being in a knowledge-based industry, many construction organizations are seeking to manage their own knowledge in an effective way. To manage knowledge, the organizations must motivate in-house people to share their knowledge. However, some barriers to knowledge sharing do exist and researches on these barriers considering construction organizations' characteristics seem rare. This study aims to identify key barriers to knowledge sharing considering the characteristics of construction organizations. Based on the identification, strategic responses to each key barrier are presented in two perspectives of technical and behavioral approach to activate knowledge sharing.

• Nuclear Engineering and Technology
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• 제53권2호
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• pp.446-454
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• 2021

Critical heat flux (CHF) has traditionally been evaluated using look-up tables or empirical correlations for nuclear power plants. However, under complex moving condition, it is necessary to reconsider the CHF characteristics since the conventional CHF prediction methods would no longer be applicable. In this paper, the additional forces caused by motions have been added to the annular film dryout (AFD) mechanistic model to investigate the effect of moving condition on CHF. Moreover, a theoretical model of the natural circulation loop with additional forces is established to reflect the natural circulation characteristics of the loop system. By coupling the system loop with the AFD mechanistic model, a CHF prediction program called NACOM for natural circulation loop under moving condition is developed. The effects of three operating conditions, namely stationary, inclination and rolling, on the CHF of the loop are then analyzed. It can be clearly seen that the moving condition has an adverse effect on the CHF in the natural circulation system. For the calculation parameters in this paper, the CHF can be reduced by 25% compared with the static value, which indicates that it is important to consider the effects of moving condition to retain adequate safety margin in subsequent thermal-hydraulic designs.

• 한국실내디자인학회논문집
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• 제14권6호
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• pp.21-28
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• 2005

Arata Isozaki is one of the Japan's most important contemporary architects with an international reputation and has designed notable buildings in Asia, Europe, and the United States. Arata Isozaki is not an architect simply explained by a single ism or style, he has dedicated himself to express all diversities implied in different periods and styles. With an avant-garde spirit and enthusiastic creativity, he has devoted all his efforts to bring these diversities and complexities into his own architectural works. The study was aimed to identify the key characteristics implied in his overall design concept. Through the analysis of his works, the key features underlined in his works were characterized by five key words, which are tradition, eclectic, metaphor, metabolism and proportion. These five characteristics have been well Presented in his works individually and sometimes as a whole. His unique combination among these key design concepts has been impressed by many other architects in worldwide.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2005년도 추계학술발표대회 논문집
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• pp.147-150
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• 2005

Arata Isozaki is one of Japan's most important contemporary architects with an international reputation and has designed notable buildings in Asia, Europe, and the United States. The study was aimed to identify the key characteristics implied in his overall design concept. Through the analysis of his works, the key features underlined in his works were characterized by five key words, which are tradition, eclectic, metaphor, metabolism and proportion . These five characteristics have been well presented in his works individually and sometimes as a whole. His unique combination among these key design concepts has been impressed by many other architects in worldwide. Through in-depth analysis of his design philosophy, this study raises a foundation for further studies on exploring an optimal solution for the harmonization between tradition and globalism.

• Nuclear Engineering and Technology
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• 제52권5호
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• pp.897-907
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• 2020

The flow characteristics of reactor fuel assembly always intrigue the designers and the experimentalists among the myriad phenomena that occur simultaneously in a nuclear core. In this work, the visual experimental method has been developed on the basis of refraction index matching (RIM) and particle image velocimetry (PIV) techniques to investigate the detailed flow characteristics in China fast reactor fuel subassembly. A 7-rod bundle of simulated fuel subassembly was fabricated for fine examination of flow characteristics in different subchannels. The experiments were performed at condition of Re=6500 (axial bulk velocity 1.6 m/s) and the fluid medium was maintained at 30℃ and 1.0 bar during operation. As for results, axial and lateral flow features were observed. It is shown that the spiral wire has an inhibitory effect on axial flow and significant intensity of lateral flow mixing effect is induced by the wire. The root mean square (RMS) of lateral velocity fluctuation was acquired after data processing, which indicates the strong turbulence characteristics in different flow subchannels.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권9호
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• pp.3266-3285
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• 2014

With limited computing and storage resources, many network applications of encryption algorithms require low power devices and fast computing components. CHESS-64 is designed by employing simple key scheduling and Data-Dependent operations (DDO) as main cryptographic components. Hardware performance for Field Programmable Gate Arrays (FPGA) and for Application Specific Integrated Circuits (ASIC) proves that CHESS-64 is a very flexible and powerful new cipher. In this paper, the security of CHESS-64 block cipher under related-key differential cryptanalysis is studied. Based on the differential properties of DDOs, we construct two types of related-key differential characteristics with one-bit difference in the master key. To recover 74 bits key, two key recovery algorithms are proposed based on the two types of related-key differential characteristics, and the corresponding data complexity is about $2^{42.9}$ chosen-plaintexts, computing complexity is about $2^{42.9}$ CHESS-64 encryptions, storage complexity is about $2^{26.6}$ bits of storage resources. To break the cipher, an exhaustive attack is implemented to recover the rest 54 bits key. These works demonstrate an effective and general way to attack DDO-based ciphers.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권1호
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• pp.145-164
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• 2014

Network virtualization provides a promising tool to allow multiple heterogeneous virtual networks to run on a shared substrate network simultaneously. A long-standing challenge in network virtualization is the Virtual Network Embedding (VNE) problem: how to embed virtual networks onto specific physical nodes and links in the substrate network effectively. Recent research presents several heuristic algorithms that only consider single topological attribute of networks, which may lead to decreased utilization of resources. In this paper, we introduce six complementary characteristics that reflect different topological attributes, and propose three topology-aware VNE algorithms by leveraging the respective advantages of different characteristics. In addition, a new KS-core decomposition algorithm based on two characteristics is devised to better disentangle the hierarchical topological structure of virtual networks. Due to the overall consideration of topological attributes of substrate and virtual networks by using multiple characteristics, our study better coordinates node and link embedding. Extensive simulations demonstrate that our proposed algorithms improve the long-term average revenue, acceptance ratio, and revenue/cost ratio compared to previous algorithms.