• Title/Summary/Keyword: Sparse prime

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A fast exponentiation with sparse prime (Sparse 소수를 사용한 효과적인 지수연산)

  • 고재영;박봉주;김인중
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.23 no.4
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    • pp.1024-1034
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    • 1998
  • Most public cryptosystem widely used in communication network are based on the exponentiation-arithmetic. But, cryptosystem has to use bigger and bigger key parameter to attain an adequate level of security. This situation increases both computation and time delay. Montgomery, yang and Kawamura presented a method by using the pre-computation, intermediately computing and table look-up on modular reduction. Coster, Brickel and Lee persented also a method by using the pre-computation on exponentiation. This paper propose to reduce computation of exponentiation with spare prime. This method is to enhance computation efficiency in cryptosystem used discrete logarithms.

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A Novel Cost-Effective Firewall Token for Hacking Protection on TCP/IP Based Network (TCP/IP를 이용하는 전산망의 해킹방지를 위한 경제적인 방화벽 토큰 설계 방안)

  • 고재영
    • Journal of the Korea Institute of Military Science and Technology
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    • v.2 no.1
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    • pp.159-169
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    • 1999
  • Recently a firewall is being employed to protect hacking by controlling the traffics. The security services in the firewall include authentication, access control, confidentiality, integrity, and audit trail. A token is adapted for authentication to the firewall. A token has a small battery within which has restricted power capacity, This paper proposes a novel cost-effective firewall token for hacking protecting on transmission control protocol/internet protocol (TCP/IP) based network. This paper proposes a fast exponentiation method with a sparse prime that take a major operation for a public-key crypto-system and a major power consumption in the token. The proposed method uses much less amount of modular operations in exponentiation that is reduced of battery's capacity or CPU's price in the token.

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Fast DFT Matrices Transform Based on Generalized Prime Factor Algorithm

  • Guo, Ying;Mao, Yun;Park, Dong-Sun;Lee, Moon-Ho
    • Journal of Communications and Networks
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    • v.13 no.5
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    • pp.449-455
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    • 2011
  • Inspired by fast Jacket transforms, we propose simple factorization and construction algorithms for the M-dimensional discrete Fourier transform (DFT) matrices underlying generalized Chinese remainder theorem (CRT) index mappings. Based on successive coprime-order DFT matrices with respect to the CRT with recursive relations, the proposed algorithms are presented with simplicity and clarity on the basis of the yielded sparse matrices. The results indicate that our algorithms compare favorably with the direct-computation approach.

The Gradient Variation of Thermal Environments on the Park Woodland Edge in Summer - A Study of Hadongsongrim and Hamyangsangrim - (여름철 공원 수림지 가장자리의 온열환경 기울기 변화 - 하동송림과 함양상림을 대상으로 -)

  • Ryu, Nam-Hyong;Lee, Chun-Seok
    • Journal of the Korean Institute of Landscape Architecture
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    • v.43 no.6
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    • pp.73-85
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    • 2015
  • This study investigated the extent and magnitude of the woodland edge effects on users' thermal environments according to distance from woodland border. A series of experiments to measure air temperature, relative humidity, wind velocity, MRT and UTCI were conducted over six days between July 31 and August 5, 2015, which corresponded with extremely hot weather, at the south-facing edge of Hadongsongrim(pure Pinus densiflora stands, tree age: $100{\pm}33yr$, tree height: $12.8{\pm}2.7m$, canopy closure: 75%, N $35^{\circ}03^{\prime}34.7^{{\prime}{\prime}}$, E $127^{\circ}44^{\prime}43.3^{{\prime}{\prime}}$, elevation 7~10m) and east-facing edge of Hamyangsangrim (Quercus serrata-Carpinus tschonoskii community, tree age: 102~125yr/58~123yr, tree height: tree layer $18.6{\pm}2.3m/subtree$ layer $5.9{\pm}3.2m/shrub$ layer $0.5{\pm}0.5m$, herbaceous layer coverage ratio 60%, canopy closure: 96%, N $35^{\circ}31^{\prime}28.1^{{\prime}{\prime}}$, E $127^{\circ}43^{\prime}09.8^{{\prime}{\prime}}$, elevation 170~180m) in rural villages of Hadong and Hamyang, Korea. The minus result value of depth means woodland's outside. The depth of edge influence(DEI) on the maximum air temperature, minimum relative humidity and wind speed at maximum air temperature time during the daytime(10:00~17:00) were detected to be $12.7{\pm}4.9$, $15.8{\pm}9.8$ and $23.8{\pm}26.2m$, respectively, in the mature evergreen conifer woodland of Hadongsongrim. These were detected to be $3.7{\pm}2.2$, $4.9{\pm}4.4$ and $2.6{\pm}7.8m$, respectively, in the deciduous broadleaf woodland of Hamyansangrim. The DEI on the maximum 10 minutes average MRT, UTCI from the three-dimensional environment absorbed by the human-biometeorological reference person during the daytime(10:00~17:00) were detected to be $7.1{\pm}1.7$ and $4.3{\pm}4.6m$, respectively, in the relatively sparse woodland of Hadongsongrim. These were detected to be $5.8{\pm}4.9$ and $3.5{\pm}4.1m$, respectively, in the dense and closed woodland of Hadongsongrim. Edge effects on the thermal environments of air temperature, relative humidity, wind speed, MRT and UTCI in the sparse woodland of Hadongsongrim were less pronounced than those recorded in densed and closed woodland of Hamyansangrim. The gradient variation was less steep for maximum 10 minutes average UTCI with at least $4.3{\pm}4.6m$(Hadongsongrim) and $3.5{\pm}4.1m$(Hamyansangrim) being required to stabilize the UTCI at mature woodlands. Therefore it is suggested that the woodlands buffer widths based on the UTCI values should be 3.5~7.6 m(Hamyansangrim) and 4.3~8.9(Hadongsongrim) m on each side of mature woodlands for users' thermal comfort environments. The woodland edge structure should be multi-layered canopies and closed edge for the buffer effect of woodland edge on woodland users' thermal comfort.

Design of a High Temperature Production Heat Pump System Using Geothermal Water at Moderate Temperature (중온 지열수를 이용한 고온제조 열펌프 시스템 해석 및 설계)

  • Kim, Min-Sung;Baik, Young-Jin;Park, Seong-Ryong;Chang, Ki-Chang;Lee, Young-Soo;Ra, Ho-Sang
    • 한국신재생에너지학회:학술대회논문집
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    • 2008.05a
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    • pp.638-641
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    • 2008
  • Geothermal water at moderate temperature in a range between 30 to $50^{\circ}C$ exists sparse in surroundings. Mostly they are utilized as heat or water source at spar zones in Korea. However, a large portion of used water is discarded due to its poor recovery quality and inferior application technologies. In this research, an innovative heat pump system based on the hybrid concept that combinate compression cycle and absorption cycle was investigated mathematically. The hybrid heat pump aims to recycle various kind of the heat sources at moderate temperature including geothermal water effectively. The prime objective of the simulation is to design a compression/absorption hybrid heat pump system which can make high temperature above the level of $90^{\circ}C$ and low temperature of $20^{\circ}C$ as well at the same using $50^{\circ}C$ geothermal heat water. As a result, primitive data was provided as a basis to design a prototype 3 RT class hybrid heat pump.

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Fast Binary Block Inverse Jacket Transform

  • Lee Moon-Ho;Zhang Xiao-Dong;Pokhrel Subash Shree;Choe Chang-Hui;Hwang Gi-Yean
    • Journal of electromagnetic engineering and science
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    • v.6 no.4
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    • pp.244-252
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    • 2006
  • A block Jacket transform and. its block inverse Jacket transformn have recently been reported in the paper 'Fast block inverse Jacket transform'. But the multiplication of the block Jacket transform and the corresponding block inverse Jacket transform is not equal to the identity transform, which does not conform to the mathematical rule. In this paper, new binary block Jacket transforms and the corresponding binary block inverse Jacket transforms of orders $N=2^k,\;3^k\;and\;5^k$ for integer values k are proposed and the mathematical proofs are also presented. With the aid of the Kronecker product of the lower order Jacket matrix and the identity matrix, the fast algorithms for realizing these transforms are obtained. Due to the simple inverse, fast algorithm and prime based $P^k$ order of proposed binary block inverse Jacket transform, it can be applied in communications such as space time block code design, signal processing, LDPC coding and information theory. Application of circular permutation matrix(CPM) binary low density quasi block Jacket matrix is also introduced in this paper which is useful in coding theory.

Development of a Compression/Absorption Hybrid Heat Pump System Using $NH_3/H_2O$ Mixture for High Temperature Generation ($NH_3/H_2O$를 이용한 압축-흡수식 고온제조 하이브리드 히트펌프 시스템 개발)

  • Kim, Min-Sung;Baik, Young-Jin;Shin, Kwang-Ho;Park, Seong-Ryong;Chang, Ki-Chang;Lee, Young-Soo;Ra, Ho-Sang
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.1249-1254
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    • 2008
  • Industrial low temperature waste heat exists sparse in surroundings but its amount is huge. However, large portion of waste heat is discarded due to its poor recovery quality and inferior application technologies. The heat pump system in this research is based on the hybrid combination of compression cycle and absorption cycle in order to recycle various kind of industrial waste heat effectively. The prime objective is to design a compression absorption hybrid heat pump system which can produce high temperature above the level of $90^{\circ}C$ and low temperature of $20^{\circ}C$ at the same time using waste heat water of $50^{\circ}C$. A mathematical simulation was carried out as a basis to design a prototype 3 RT class hybrid heat pump. From the simulation results, fundamental parameters to design the system were obtained.

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