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排序方式: 共有617条查询结果,搜索用时 15 毫秒
71.
Xiaoying Jia Neeraj Kumar Kim‐Kwang Raymond Choo Debiao He 《International Journal of Communication Systems》2018,31(1)
The capability to efficiently revoke compromised/misbehaving users is important in identity‐based encryption (IBE) applications, as it is not a matter of if but of when that one or more users are compromised. Existing solutions generally require a trusted third party to update the private keys of nonrevoked users periodically, which impact on scalability and result in high computation and communication overheads at the key generation center. Li et al proposed a revocable IBE scheme, which outsources most of the computation and communication overheads to a Key Update Cloud Service Provider (KU‐CSP). However, their scheme is lack of scalability since the KU‐CSP must maintain a secret value for each user. Tseng et al proposed another revocable IBE scheme with a cloud revocation authority, seeking to provide scalability and improve both performance and security level. In this paper, we present a new revocable IBE scheme with a cloud revocation server (CRS). The CRS holds only one secret time update key for all users, which provides the capability to scale our scheme. We demonstrate that our scheme is secure against adaptive‐ID and chosen ciphertext attacks under the k‐CAA assumption and outperforms both schemes mentioned above, in terms of having lower computation and communication overheads. 相似文献
72.
Effects of reinforcements’ shapes, sizes and contents on (a) von-Mises stress along a horizontal line in MMCs, (b) directions and distributions of principal stresses inside particles, matrix and interface, and (c) distribution of thermal residual stress in MMCs were analysed in this investigation. It was found that the matrix–particle interfaces experience a sudden change of von-Mises stress which depends on the reinforcement shape. The smoothest change of stress occurred in triangle particle-reinforced MMCs. However, the highest stress was concentrated at the corners of the triangular particles. The directions of stress vectors depend on the shape of the particles. The extent of the von-Mises stress increases with the increase in reinforcement content and a decrease in particles size at constant content. 相似文献
73.
Seungki Jo Seungjun Choo Fredrick Kim Seung Hwae Heo Jae Sung Son 《Advanced materials (Deerfield Beach, Fla.)》2019,31(20)
The growing concern over the depletion of hydrocarbon resources, and the adverse environmental effects associated with their use, has increased the demand for renewable energy sources. Thermoelectric (TE) power generation from waste heat has emerged as a renewable energy source that does not generate any pollutants. Recently, ink‐based processing for the preparation of TE materials has attracted tremendous attention because of the simplicity in design of power generators and the possibility of cost‐effective manufacturing. In this progress report, recent advances in the development of TE inks, processing techniques, and ink‐fabricated devices are reviewed. A summary of typical formulations of TE materials as inks is included, as well as a discussion on various ink‐based fabrication methods, with several examples of newly designed devices fabricated using these techniques. Finally, the prospects of this field with respect to the industrialization of TE power generation technology are presented. 相似文献
74.
Kang Chang Mook Lee Seung-Hi Kee Seok-Cheol Chung Chung Choo 《International Journal of Control, Automation and Systems》2018,16(3):1293-1302
International Journal of Control, Automation and Systems - In this paper, we propose the use of fault-tolerant techniques for an autonomous lane keeping system (LKS) under sensor failure of the... 相似文献
75.
Hajun Dang Sung-Gyu Park Yixuan Wu Namhyun Choi Jun-Yeong Yang Seunghun Lee Sang-Woo Joo Lingxin Chen Jaebum Choo 《Advanced functional materials》2021,31(49):2105703
Electromagnetic enhancement effects through localized surface plasmon resonance considerably amplify the intensity of incident light when molecules are positioned in the vicinity of miniscule nanogaps. The aggregation of plasmonic nanoparticles synthesized using bottom-up methods has been extensively used to generate hot spots in solutions. These methods assist in obtaining non-periodic plasmonic signals, because the realization of uniform nanogaps through particle aggregation is difficult. Nanostructured substrates with gaps of 20–100 nm have also been fabricated using the top-down approach. However, the fabrication of smaller nanogap templates using these methods is difficult owing to high costs and low throughput. Therefore, a nanodimple array internalized with AuNPs is developed in this study to mitigate the challenges encountered in the bottom-up and top-down approaches. Precise nanogaps are generated by regularly internalizing AuNPs in the cavities of nanodimples through DNA hybridization. Simulations of the electric field distribution indicate that the incorporation of 80 nm-sized AuNPs into a curved nanodimpled Au substrate generate high-density volumetric hot spots within a detection volume, and result in a high plasmonic enhancement factor of 8.25 × 107. The tremendous potential of the proposed plasmonic platform as an SERS-based biomedical diagnostic device is also verified. 相似文献
76.
C. K. Lim Y. S. Choo A. Y. C. Nee 《Computer-Aided Civil and Infrastructure Engineering》1995,10(3):199-212
Abstract: A consistent representation of offshore structures and barges that is appropriate for computer processing is essential for the development of an efficient design system for offshore heavy lift installation. This paper outlines the representation of conceptual and physical entities in the preliminary design for lift installation through an object-oriented approach. The spatial and topologic abstractions of physical entities are illustrated. These abstractions, together with the locational dependency concept for an assembly, form the backbone for geometric reasoning in the top-down approach for lift installation design. An object-oriented prototype system for lift evaluation, C-LIFT, using the knowledge-based development tool kit ART* Enterprise is described. A liftability study involving the installation of offshore modules and the associated lift sequence is then presented to illustrate the advantages of this approach. 相似文献
77.
Lee TS Park KK Cho HS Choo YA Hwang M 《Journal of materials science. Materials in medicine》2008,19(3):1425-1431
Vascular smooth muscle cells (VSMCs) play a pivotal role in vascular injury through proliferation and migration. Pro-inflammatory
cytokines and cyclooxygenase (COX)-2 and nitric oxide synthase (NOS) are highly associated with the pathogenesis of VSMCs.
We investigated the effect of bioactive ceramics on the expression of inflammatory cytokines, COX-2, and inducible NOS (iNOS)
induced by phorbol 12-myristate 13-acetate (PMA) in rat VSMCs. The ceramics inhibited mRNA expression of IL-1β, TNF-α, IL-6,
COX-2, and iNOS. Prostaglandin release was also diminished by the ceramics. The bioactive ceramics effect on cytokines, COX-2,
and iNOS expression was achieved by inhibition of NF-κB activity. Interestingly, the ceramics-induced up-regulation of expression
of endothelial NOS resulted in an increase of nitric oxide production. Thus, bioactive ceramics may have dual effects on the
pathogenesis of VSMCs by regulation of NF-κB activity and NO production. 相似文献
78.
S. Y. Lee Y. L. Lu P. K. Liaw H. Choo S. A. Thompson J. W. Blust P. F. Browning A. K. Bhattacharya J. M. Aurrecoechea D. L. Klarstrom 《Mechanics of Time-Dependent Materials》2008,12(1):31-44
The creep–fatigue crack-growth tests of HASTELLOY® X alloy were carried out at the temperatures of 649°C, 816°C, and 927°C in laboratory air. The experiments were conducted under a constant stress-intensity-factor-range (ΔK) control mode with a R-ratio of 0.05. In the constant ΔK tests, a ΔK of 27.5 MPa\(\sqrt{\mathrm{m}}\) and a triangular waveform with a frequency of 0.333 Hz were used. Various tensile hold times at the maximum load were imposed to study fatigue and creep–fatigue interactions. Crack lengths were measured by a direct current potential drop method. In this paper, effects of hold time and temperature on the crack-growth rates are discussed. Furthermore, the crack-growth rates of the HASTELLOY® X alloy are compared to those of the HAYNES® 188 and HAYNES® 230® superalloys. 相似文献
79.
Lingxin Chen Qingling Li Sangyeop Lee Jaebum Choo 《IEEE sensors journal》2008,8(5):488-494
High-pressure electroosmotic pumps (EOPs) operate on the principle that electroosmotic flow (EOF) can be generated through a packed-bed capillary by applying an electric field through it. In this paper, a novel packed-bed EOP design using nanosilica particles is described. The packed-bed capillary was fabricated using a capillary of 5 cm x 530 mum i.d. close packed with silica particles having an average particle size of 20-30 nm. The flow rates, pressures and pressure/flow rate (P-Q)characteristics, electric properties of the pump and the influence of phosphate buffer concentration on the pump were carefully studied. By increasing the pressure, decreasing the applied voltage, and the electric current, the thermodynamic efficiency was about 1%-2% for inorganic buffers and 3%-5% for organic solvents or their mixture without ions. 相似文献
80.
Lee S Kim S Choo J Shin SY Lee YH Choi HY Ha S Kang K Oh CH 《Analytical chemistry》2007,79(3):916-922
Surface-enhanced Raman scattering (SERS) imaging has been used for the targeting and imaging of specific cancer markers in live cells. For this purpose, Au/Ag core-shell nanoparticles, conjugated with monoclonal antibodies, were prepared. The procedures to label live cells with those bimetallic nanoprobes have been developed and used for highly sensitive SERS imaging of live cells. In the present study, live HEK293 cells expressing PLCgamma1 have been used as the optical imaging target. Our results demonstrate the potential feasibility of SERS imaging technology for the highly sensitive imaging of cancer biomarkers in live cells. 相似文献