به نام خدا
Title: Large nonadiabatic quantum molecular dynamics simulations on parallel computers
Authors: Fuyuki Shimojo , Satoshi Ohmura , Weiwei Mou , Rajiv K Kalia , Aiichiro Nakano , Priya Vashishta
Abstract: Wehave implemented a quantummolecular dynamics simulation incorporating nonadiabatic electronic transitions on massively parallel computers to study photoexcitation dynamics of electrons and ions. The nonadiabatic quantum molecular dynamics (NAQMD) simulation is based on Casida s linear response time-dependent density functional theory to describe electronic excited states and Tully s fewest- switches surface hopping approach to describe nonadiabatic electron ion dynamics. To enable large NAQMD simulations, a series of techniques are employed for efficiently calculating long-range exact exchange correction and excited-state forces. The simulation programis parallelized using hybrid spatial and band decomposition, and is tested for various materials.
Publish Year: 2013
Published in: Computer Physics Communications - Science Direct
موضوع: محاسبات کوانتوم (Quantum Computing )
ایران سای – مرجع علمی فنی مهندسی
حامی دانش بومی ایرانیان
به نام خدا
Title: Molecular solutions of the RSA public-key cryptosystem on a DNA-based computer
Authors: WengLong Chang Kawuu Weicheng Lin JuChin Chen ChihChiang Wang Lai Chin Lu Minyi Guo Michael ShanHui Ho
Abstract: The RSA public-key cryptosystem is an algorithm that converts a plain-text to its corresponding cipher-text, and then converts the cipher-text back into itscorresponding plain-text. In this article, we propose five DNA-based algorithms-parallel adder, parallel subtractor, parallel multiplier, parallel comparator, and parallelmodular arithmetic-that construct molecular solutions for any (plain-text, cipher-text) pair for the RSA public-key cryptosystem.
Publish Year: 2012
Published in: The Journal of Supercomputing - Springer
موضوع: رمزنگاری کلید عمومی (Public Key Cryptography)، محاسبات کوانتوم (Quantum Computing)
ایران سای – مرجع علمی فنی مهندسی
حامی دانش بومی ایرانیان
به نام خدا
Title: Secure E-Commerce Protocol for Purchase of e-Goods - Using Smart Card
Authors: Devane, S.; Chatterjee, M.; Phatak, D.
Abstract: The rapid growth of e-commerce for buying and selling electronic goods or intangible goods has necessitated the need for development of a number of e-commerce protocols, which ensure integrity, confidentiality, atomicity and fair exchange. In this paper we propose an e-commerce protocol for performing business over the Internet. The protocol uses a smart card for ensuring mutual authentication, dispute resolution and fair exchange and reduces reliance on a trusted third party. Atomicity is also maintained in the protocol.
Publish Year: 2007
Published by: IAS – IEEE
موضوع: تجارت الکترونیک (Electronic Commerce)
ایران سای – مرجع علمی فنی مهندسی
حامی دانش بومی ایرانیان
به نام خدا
Title: Sharding Social Networks
Authors: Quang Duong, Sharad Goel, Jake Hofman, Sergei Vassilvitskii
Abstract: Online social networking platforms regularly support hun-dreds of millions of users, who in aggregate generate sub-stantially more data than can be stored on any single phys-ical server. As such, user data are distributed, or sharded,across many machines. A key requirement in this setting israpid retrieval not only of a given user_s information, butalso of all data associated with his or her social contacts,suggesting that one should consider the topology of the so-cial network in selecting a sharding policy. In this paperwe formalize the problem of efficiently sharding large so-cial network databases, and evaluate several sharding strate-gies, both analytically and empirically. We find that randomsharding-the de facto standard-results in provably poorperformance even when frequently accessed nodes are repli-cated to many shards. By contrast, we demonstrate that onecan substantially reduce querying costs by identifying andassigning tightly knit communities to shards. In particular,our theoretical analysis motivates a novel, scalable shardingalgorithm that outperforms both random and location-basedsharding schemes.
Publish Year: 2013
Published by: ACM-WSDM
موضوع: شبکه های اجتماعی (Social Netwroks)
ایران سای – مرجع علمی فنی مهندسی
حامی دانش بومی ایرانیان
به نام خدا
Title: Efficient and dynamic key management for multiple identities in identity-based systems
Authors: Hua Guo , Chang Xu a , Zhoujun Li a , Yanqing Yao a , Yi Mu
Abstract: The traditional identity-based cryptography requires a user, who holds multiple identities, to hold multiple private keys, where each private key is associated with an identity. Man- aging multiple private/public keys is a heavy burden to a user due to key management and storage. The recent advancement of identity-based cryptography allow a single private key to map multiple public keys (identities); therefore the private key management is simpli- fied. Unfortunately, the existing schemes capturing this feature do not allow dynamic changes of identities and have a large data size proportional to the number of the associ- ated identities. To overcome these problems, in this paper, we present an efficient and dynamic identity-based key exchange protocol and prove its security under the Bilinear Diffie Hellman assumption in the random oracle model. Our protocol requires a relatively small bandwidth for a key agreement communication, in comparison with other existing schemes.
Publish Year: 2013
Published in: Information Sciences - Science Direct
موضوع: رمزنگاری
ایران سای – مرجع علمی فنی مهندسی
حامی دانش بومی ایرانیان
