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Fundamentals of Multimedia Encryption Techniques
Published in Borko Furht, Darko Kirovski, Multimedia Security Handbook, 2004
Borko Furht, Daniel Socek, Ahmet M. Eskicioglu
To solve these problems, researchers introduced different approaches. In order to decrease the key size so that public key cryptography can be used in smaller computational environments (such as smart cards or handheld wireless devices), Neil Koblitz introduced the idea of using a more exotic group in the public key underlying algebraic structure: the elliptic curve group. Elliptic curve cryptography (much of whose implementation is credited to CertiCom) enables smaller key sizes of public key cryptosystems that rely on DLP. The elliptic-curve-group algebra is much more complex, so the related cryptanalysis is much harder, resulting in smaller key requirements. Another solution came from public key cryptosystems that initially used more complex computational problem, such as the lattice reduction problem. The relatively new cryptosystem NTRU based on the algebra of a ring of truncated polynomials relies on the lattice reduction problem and it is the only public key cryptosystem that has the speed, memory, and computational complexity comparable to symmetric key cryptosystems. However, the security aspects of NTRU are yet to be investigated [4,5]. The most common implementation solution is to combine symmetric key cryptosystems with public key cryptography; namely to overcome the problems related to applying the symmetric key encryption only, the plaintext is encrypted using a fast symmetric key scheme, and only the secret key used for symmetric encryption is encrypted with the slow public key scheme such as RSA. In this way, all goals of cryptography can be achieved with a much better performance.
Performance analysis of alternating minimization based low complexity detection for MIMO communication system
Published in Automatika, 2023
Kasiselvanathan M., Manikandan Rajagopal, Teresa V. V., Prabhakar Krishnan
Hybrid BP (Belief Propagation) and EP (Expectation Propagation) receivers, initially addressed BP algorithm’s convergence issue using auxiliary variables in factor graph-based near-optimal iterative receivers [28]. Jiang et al. [29] suggested quick processing approaches with low complexity and provided iterative receivers to comprehend linear inverse matrices issues. The iterative technique updated the process separately on a small-size block by using the block matrix attributes. MIMO detection with minimal complexity utilising adaptive mitigation is introduced by Park et al. [30]. Imperfect precoded matrices were used by quantization error-based downlinked multiuser MIMO to lessen interferences and receive required signals at receivers. To achieve reduced complexities, Zhao and Du [31] suggested LRA (lattice reduction assisted) based MIMO detections.
Effect of Sr-doping on electronic and thermal properties of Pr2-xSrxFeCrO6 (0≤x≤1) oxide materials synthesized by using sol-gel technique
Published in Journal of Asian Ceramic Societies, 2023
Lav Kush, Sanjay Srivastava, Sanjay Kumar Vajpai, Serguei V. Savilov
Finally, the ZT was computed and presented in Figure 8 based on the observed electrical characteristics at various temperatures. Lower S and higher σ provide a remarkably high ZT, which was further enhanced by selective Sr-doping in Pr2-xSrxFeCrO6 double perovskites from x = 0 to 1. In the Pr2-xSrxFeCrO6 double perovskite, the Sr content has a considerable influence on the temperature dependence of ZT. The ZT of samples with low Sr content obviously rises linearly, but samples with high Sr content (x ≥ 0.5) exhibit an exponential rise in ZT, which reaches a maximum of 0.105 at 942 K for x = 1.0 and was around 3.9 times greater than the pure compound (x = 0.0). It was observed that, throughout the entire composition (x = 0 to 1), the ZT values increased due to the substitution of Sr on the Pr-site up to a certain temperature, then decreased with further increase in temperature, and varied slightly depending on the transport properties and lattice reduction [52–55, , 56]. Unexpectedly, this ZT in Pr2-xSrxFeCrO6 double perovskite value was greater than the already researched p-type Pr2CoFeO6 (ZT = 0.05 at 673 K) [20], and Ca2(ZnxFe2-x)O5 (ZT = 0.002 at 1073 K) 52,53], earlier published values. This demonstrates how carefully choosing the dopants may significantly increase the ZT of Pr2-xSrxFeCrO6 double perovskite.
Surface and Constriction Engineering of Nanoparticle Based Structures Towards Ultra-Low Thermal Conductivity as Prospective Thermoelectric Materials
Published in Nanoscale and Microscale Thermophysical Engineering, 2023
Pasan Henadeera, Nalaka Samaraweera, Chathura Ranasinghe, Anusha Wijewardane
The effect of shell atom removal on the is then evaluated and presented in Figure 12, based on the percentage of shell atoms removed from the structure. In contrast to other methods such as core/shell variants and increased constriction ratios of NPC structures, the removal of surface atoms in NPC structures has an insignificant impact on the . This effect can be hypothesized to be caused owing to the roughness imposed on the surface due to the curvature of the nanoparticles. Hence, small removal rates from the surface tend to have a negligible impact on the phonon transport in NPC structures unlike what was previously observed with nanowires [23]. This indicates that the contribution to the lattice reduction by the increased phonon boundary scattering due to the surface roughness is insignificant. However, larger removal rates tend to make the structure unstable, thus making the surface atom removal process unfeasible for reduction in NPC structures.