• Nuclear Engineering and Technology
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• 제53권9호
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• pp.2960-2967
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• 2021

In this work, a new hardening model is proposed for the depth-dependent hardness of ion-irradiated polycrystals with obvious grain size effect. Dominant hardening mechanisms are addressed in the model, including the contribution of dislocations, irradiation-induced defects and grain boundaries. Two versions of the hardening model are compared, including the linear and square superposition models. A succinct parameter calibration method is modified to parametrize the models based on experimentally obtained hardness vs. indentation depth curves. It is noticed that both models can well characterize the experimental data of unirradiated polycrystals; whereas, the square superposition model performs better for ion-irradiated materials, therefore, the square superposition model is recommended. In addition, the new model separates the grain size effect from the dislocation hardening contribution, which makes the physical meaning of fitted parameters more rational when compared with existing hardness analysis models.

• 인터넷정보학회논문지
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• 제17권5호
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• pp.97-110
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• 2016

Cryptanalysis is very important step for auditing and checking strength of any cryptosystem. Some of these cryptosystem ensures confidentiality and security of large information exchange from source to destination using symmetric key cryptography. The cryptanalyst investigates the strengths and identifies weakness key as well as enciphering algorithm. With increase in key size the time and effort required to guess the correct key increases so trend is increase key size from 8, 16, 24, 32, 56, 64, 128 and 256 bits to strengthen the cryptosystem and thus algorithm continues without compromise on the cost of time and computation. Automatic Variable Key (AVK) approach is an alternative to the approach of fixing up key size and adding security level with key variability adds new dimension in the development of secure cryptosystem. Likewise, whenever any new cryptographic method is invented to replace per-existing vulnerable cryptographic method, its deep analysis from all perspectives (Hacker / Cryptanalyst as well as User) is desirable and proper study and evaluation of its performance is must. This work investigates AVK based cryptic techniques, in future to exploit benefits of advances in computational methods like ANN, GA, SI etc. These techniques for cryptanalysis are changing drastically to reduce cryptographic complexity. In this paper a detailed survey and direction of development work has been conducted. The work compares these new methods with state of art approaches and presents future scope and direction from the cryptic mining perspectives.

• 정보보호학회논문지
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• 제17권3호
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• pp.35-42
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• 2007

본 논문은 Even-Mansour 암호에 대해 안전성 약화 없이 키 사이즈를 줄이는 방법에 대해 다룬다. Even과 Mansour는 랜덤 순열 모델에서 랜덤 순열 P와 두 개의 키를 이용하여 평문 M을 암호화하는 기법($C=k_2\bigoplus P(M\bigoplus k_1)$)을 제안하였다. ASIACRYPT 2004에서 Gentry와 Ramzen은 4 라운드의 Feistel 구조를 이용하여 Even-Mansour 모델의 랜덤 순열을 랜덤 함수로 대치한 새로운 모델을 제안하고 안전성을 증명하였다. 본 논문에서는 Gentry-Ramzen 모델에 필요한 키 사이를 반으로 줄이는 방법을 살펴보고 제안한 방법에 대한 안전성을 랜덤 함수 모델에서 증명한다.

• Asian-Australasian Journal of Animal Sciences
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• 제30권4호
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• pp.554-561
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• 2017

Objective: This experiment was conducted as a $3{\times}2{\times}2$ factorial design to examine the effects of particle size (mean particle size of 331, 640, or $862{\mu}m$), evaluation method (direct vs indirect method) and adaptation duration (7 or 26 days) on the energy content and the apparent total tract digestibility (ATTD) of various chemical components in wheat when fed to finishing pigs. Methods: Forty-two barrows ($Duroc{\times}Landrace{\times}Yorkshire$) with an initial body weight of $63.0{\pm}0.8kg$ were individually placed in metabolic cages and randomly allotted to 1 of 7 diets with 6 pigs fed each diet. For the indirect method, the pigs were fed either a corn-soybean meal based basal diet or diets in which 38.94% of the basal diet was substituted by wheat of the different particle sizes. In the direct method, the diets contained 97.34% wheat with the different particle sizes. For both the direct and indirect methods, the pigs were adapted to their diets for either 7 or 26 days. Results: A reduction in particle size linearly increased the digestible energy (DE) and metabolizable energy (ME) contents as well as the ATTD of gross energy, crude protein, organic matter, ether extract (EE) and acid detergent fiber (ADF) (p<0.05), and had a trend to increase the ATTD of dry matter of wheat (p = 0.084). The DE, ME contents, and ATTD of gross energy, crude protein, dry matter and organic matter were higher (p<0.05) when determined by the direct method, but the ATTD of ADF, EE, and neutral detergent fiber were higher when determined by the indirect method (p<0.05). Prolongation of the adaption duration decreased the ATTD of neutral detergent fiber (p<0.05) and had a trend to increase the ATTD of EE (p = 0.061). There were no interactions between particle size and the duration of the adaptation duration. The ATTD of EE in wheat was influenced by a trend of interaction between method and adaptation duration (p = 0.074). The ATTD of ADF and EE in wheat was influenced by an interaction between evaluation method and wheat particle size such that there were linear equations (p<0.01) about ATTD of ADF and EE when determined by the direct method but quadratic equations (p = 0.073 and p = 0.088, respectively) about ATTD of ADF and EE when determined by the indirect method. Conclusion: Decreasing particle size can improve the DE and ME contents of wheat; both of the direct and indirect methods of evaluation are suitable for evaluating the DE and ME contents of wheat with different particle sizes; and an adaptation duration of 7 d is sufficient to evaluate DE and ME contents of wheat in finishing pigs.

• Asian-Australasian Journal of Animal Sciences
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• 제22권1호
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• pp.107-112
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• 2009

This study was conducted to investigate the effect of feed particle size and feed form on growth performance, nutrient metabolizability and intestinal morphology in broiler chickens. This experiment was a 2${\times}$2 factorial arrangement including two feed particle sizes (fine and coarse) and two feed forms (mash and pellet). A total of two hundred and eighty eight day-old male Arbor Acre broilers were used in this six week experiment. Birds were randomly allotted to four dietary treatments with six replicates per treatment and twelve birds per replicate. The results showed that pelleting diets resulted in greater ADG (p<0.01), greater ADFI (p<0.01) and lower feed to gain ratio (F/G) (p<0.05) during starter, grower and overall period. Also, pelleting improved both apparent metabolizable energy (AME) (p<0.01) and the apparent metabolizability of crude protein (p<0.05) and organic matter (p<0.05) regardless of the phase. Reduction of feed particle size enhanced AME (p<0.05) during d 19 to 21. Increased villus height (p<0.05) and crypt depth ratio (p< 0.05) within duodenum, jejunum, and ileum were observed in birds fed the pellet diet compared with those given the mash diet. In conclusion, results indicated that feed pellets might enhance performance by improving nutrient metabolizability and digestive tract development.

• 정보학연구
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• 제3권1호
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• pp.61-72
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• 2000

본 논문에서는 RSA 공개키 암호시스템에서 암호의 안전성을 위하여 증가되는 암호키(key)의 비트 크기에 대응한 내부 연산기 설계를 효율적으로 할 수 있는 bit-slice형 모듈러 곱셈 알고리즘을 제안하였고, 제안된 알고리즘에 따른 모듈러 곱셈기를 FPGA칩을 이용하여 구현함으로써 제안된 알고리즘의 동작을 검증하였다. 제안된 bit-slice형 모듈러 곱셈 알고리즘은 Walter 알고리즘을 수정하여 도출하였으며, 구현된 모듈러 곱셈기는 bit-slice 구조로 되어 암호키(key)의 비트 확장에 대응한 모듈러 곱셈기의 오퍼랜드 비트 확장이 용이하며, 표준 하드웨어 기술언어(VHDL)로 모델링 하여 전용 하드웨어로 설계되는 RSA 공개키 암호 시스템의 구현에 응용될 수 있도록 하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권3호
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• pp.1376-1395
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• 2018

UOV is one of the most important signature schemes in Multivariate Public Key Cryptography (MPKC). It has a strong security guarantee and is considered to be quantum-resistant. However, it suffers from large key size and its signing procedure is relatively slow. In this paper, we propose a new secure UOV variant (Circulant UOV) with shorter private key and higher signing efficiency. We estimate that the private key size of Circulant UOV is smaller by about 45% than that of the regular UOV and its signing speed is more than 14 times faster than that of the regular UOV. We also give a practical implementation on modern x64 CPU, which shows that Circulant UOV is comparable to many other signature schemes.

• The Journal of Asian Finance, Economics and Business
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• 제5권4호
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• pp.57-65
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• 2018

With the paramount importance of key account management in business-to-business relationship, today companies are using this approach as a strategic weapon in their selling efforts targeted at the most important customers to solve their complex requirements with special treatment that eventually ensures both parties' financial and nonfinancial objectives. The aim of this paper is to investigate the level of key account management performance among the export-oriented readymade garments companies in Bangladesh with regards to company's experience in business, size of the company and key account serving capacity of the company. Using a questionnaire, data from 112 readymade garments companies in Bangladesh were collected and analyzed using descriptive analysis and ANOVA to test the level of key account management performance. Results show that the level of key account management performance by the garments companies did not vary by the company's experience in business and size of the company respectively. In contrast, the level of key account management performance was found to be different concerning high, medium, and low customer service capacity. Apparently, companies with big number of customers show better performance than companies with small number of customer. Implications for this study are discussed along with suggestions for future research avenues.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.702-703
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• 2006

The particle size distribution and shape are among the important parameters for characterisation of quality of metal powders. Specific material properties such as ability to flow, reactivity as well as compressibility and its hardening potentials hence the most important characteristics of sintered metals - are determined by the size distribution and shape. The correct particle size distribution and particle shape information are the key to best product quality in atomisation processes of aluminium, milling of pure metals and other processes. This paper presents state-of-the-art technology for characterization of particle size distribution and shape.

• Geomechanics and Engineering
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• 제17권4호
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• pp.405-411
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• 2019

A significant influence of the particle size distribution on the resilient behaviour of granular aggregates was usually observed in laboratory tests. However, the mechanisms underlying this phenomenon were rarely reached. In this study, a mechanistic model considering particle breakage is proposed. It is found to be the combined effects of the coefficient of uniformity and the size range between maximum and minimum particle sizes that influences the resilient modulus of granular aggregates. The resilient modulus is found to undergo reduction with evolution of particle breakage by shifting the initial particle size distribution to a broader one.