110,451 research outputs found
A Formal Proof of Zhu\u27s Signature Scheme
No full textFollowing from the remarkable works of Cramer and Shoup \cite{CS}, three trapdoor hash signature variations have been
presented in the literature: the first variation was presented in CJE\u2701 by Zhu \cite{Zhu}, the second variation was
presented in SCN\u2702 by Camenisch and Lysyanskaya \cite{CL} and the third variation was presented in PKC\u2703 by Fischlin
\cite{Fis}. All three mentioned trapdoor hash signature schemes have similar structure and the security of the last two
modifications is rigorously proved. We point out that the distribution of variables derived from Zhu\u27s signing oracle
is different from that generated by Zhu\u27s signing algorithm since the signing oracle in Zhu\u27s simulator is defined over
, instead of . Consequently the proof of security of Zhu\u27s signature scheme should be studied more precisely.
We also aware that the proof of Zhu\u27s signature scheme is not a trivial work which is stated below:
\begin{itemize}
\item the technique presented by Cramer and Shoup \cite{CS} cannot be applied directly to prove the security of Zhu\u27s
signature scheme since the structure of Cramer-Shoup\u27s trap-door hash scheme is double deck that is easy to simulate a
signing query as the order of subgroup is a public parameter;
\item the technique presented by Camenisch and
Lysyanskaya \cite{CL} cannot be applied directly since there are extra security parameters and guide the
statistical closeness of the simulated distributions to the actual distribution;
\item the technique presented by
Fischlin cannot be applied directly to Zhu\u27s signature scheme as the security proof of Fischlin\u27s signature relies on a
set of pairs while the security proof of Zhu\u27s signature should rely on a set of
pairs .
\end{itemize}
In this report, we provide an interesting random argument technique to show that Zhu\u27s signature scheme immune to
adaptive chosen-message attack under the assumptions of the strong RSA problem as well as the existence of collision
free hash functions
Computation of admissible marking sets in weighted synchronization-free petri nets by dynamic programming
No full textWe study the computation of admissible marking sets in generalized Petri nets. We first show that the admissibility checking in the generalized Petri net is NP-hard. Then, we consider a special subclass of generalized Petri nets called weighted-synchronization-free nets in which each transition has at most one input place. For a net in this subclass, we propose a generating function to compute by dynamic programming the set of admissible markings for a given generalized mutual exclusion constraint
AE monitoring of crack evolution on UHPC deck layer of a long-span cable-stayed bridge
No full textThe UHPC deck layer may be susceptible to cracking during construction, raising concerns for bridge engineering utilizing this advanced material. Addressing the issue of drying shrinkage cracking observed on the UHPC deck layer of a cable-stayed bridge, a real-time investigation into crack evolution was conducted. This study employed acoustic emission (AE) technique with in-situ data processing, focusing on AE time series analysis. Additionally, triangulation techniques were utilized to determine the AE source positions of active cracks. The results showed continuous crack evolution on the UHPC deck layer, mainly due to construction vehicles, with two major instances of crack propagation and arrest. AE signals correlated with measured crack propagation, with two major AE events matching recorded crack jumps. Later AE sources indicated a step-by-step crack tip advancement. This paper underscores the effectiveness of the AE technique for crack identification and real-time monitoring of in-service bridges
Pholcus jixianensis Zhu & Yu 1983
No full textPholcus jixianensis Zhu & Yu, 1983 (Fig. 19) Pholcus jixianensis Zhu & Yu, 1983, in Zhu, Mao & Yu 1983: 136, f. 2a–h. Diagnosis. Similar to P. suizhongicus, but can be distinguished from it by the shape of the tip of the procursus (Figs. 19E–F), by the short thumb-shaped appendix (Fig. 19E); and by the longer ventral apophysis of the trochanter (Fig. 19C). Redescription. Male: A specimen measured (‘allotype’, data copied from Zhu, Mao and Yu 1983), total length 5.0: cephalothorax 1.6 long, 1.6 wide; abdomen 3.4 long, 1.6 wide. Leg I: 40.9 (9.4+12.5+16.5+2.5). Carapace short, broad and almost circular, ochre, with brown mark broadly connecting to ocular area. Cephalic region raised, with brown central marks, ocular area dark yellow. Clypeus slightly ochre, with yellow marks. Chelicerae with pair of black apophyses distally and pair of unsclerotized rounded apophyses proximolaterally. Labium and endites yellow. Sternum slightly ochre, with some regular yellow marks on it. Femora, patellae and tibiae ochre, with dark rings, metatarsi and tarsi brown. Abdomen cylindrical, pale ochre, dorsum with pairs of brown spots on it. Venter pale brown, without marks. Palps as in Figs. 19E and 19F, bulb with ear-shaped uncus and a small thumb-shaped appendix. Procursus as in Fig. 19D. Female: in general very similar to male. A specimen measured (holotype, data copied from Zhu, Mao and Yu 1983), total length 5.3: cephalothorax 1.8 long, 1.8 wide; abdomen 3.5 long, 1.45 wide. Epigynum roughly rectangular as in Fig. 19A, with a small knob-shaped apophysis centrally. Dorsal view as in Fig. 19B, with a door-like sclerotized arch anteriorly and a pair of pine-cone pore plates. Distribution. Known from type locality only. Material. Types. Female holotype, male ‘allotype’ (labeled 82001), collected under a stone near the river, Lianhe Village, Ji County, Tianjin Municipality, China, July 30, 1982, leg. Z. X. Yu (BMU); 4♂, 3♀ paratypes, same data as holotype (TPPS). Material examined. CHINA: Tianjin: Ji County, July 30, 1982, leg. Z. X. Yu, only right palp of male and epigynum (from female holotype and male ‘allotype’).Published as part of Zhang, Feng & Zhu, Ming-Sheng, 2009, A review of the genus Pholcus (Araneae: Pholcidae) from China, pp. 1-114 in Zootaxa 2037 (1) on page 41, DOI: 10.11646/zootaxa.2235.1.2, http://zenodo.org/record/531760
A low-Reynolds-number actuator driven by instability: rotating or oscillating
No full textDue to an electro-hydrodynamic instability, a dielectric spherical particle immersed in a dielectric viscous solvent can exhibit steady rotation spontaneously (Quincke rotation) in a uniform steady electric field of sufficient strength. The recent works [Zhu and Stone, Phys Rev Fluids, 4(6):061701, 2019; Zhu and Stone, J Fluid Mech, p 888, 2020; Han et al., Proc Natl Acad Sci USA, 118(29), 2021] have demonstrated using an elastic structure to tune that instability for generating self-oscillation via an elasto-electro-hydrodynamic instability. Inspired by these studies, here, we use simulations to conceive a low-Reynolds-number actuator made of a dielectric spherical particle attached to an anchor via a flexible filament. We show that the actuator displays multiple behaviors: stationary, two modes of steady rotation, and a self-oscillatory motion, depending on the ratio μ ̄ of the viscous over elastic forces, slenderness of the filament, and the strength of the electric field. The complex dependence is illustrated by bifurcation diagrams revealing multiple features of the dynamical system. We then develop a reduced-order model that captures the main features of the dynamics revealed by the full model. A linear stability analysis is also performed to predict the onset of instability of the model system, which agrees well with the numerical results
Age hardening and softening in cold-rolled Al-Mg-Mn alloys with up to 0.4wt%Cu
No full textThe age hardening and age softening of nine solution treated and subsequently cold-rolled Al-(1-3)Mg-(0-0.4)Cu-0.15Si-0.25Mn (in wt%) alloys with potential applications in both packaging and automotive industries have been investigated. Cold work levels were 10, 40 and 90% reduction. The proof strengths of the aged alloys range from 130 to 370MPa. A physically based model for yield strength has been developed which includes a one parameter dislocation evolution model to describe work hardening and recovery and a two precipitate precipitation hardening model. The model is based on analytical equations, avoiding computing time intensive iterative schemes. An exceptionally high model accuracy has been demonstrated. The model parameters are verified by transmission electron microscopy and calorimetry analysis of the materials
A multi-wavelength study of the gravitational lens COSMOS~J095930+023427
No full textWe present a multi-wavelength study of the gravitational lens
COSMOS~J095930+023427 (), together
with the associated galaxy group located at along the line of sight and
the lensed background galaxy.
The source redshift is currently unknown, but estimated to be at .
The analysis is based on the available public HST, Subaru, Chandra imaging data, and VLT
spectroscopy.
The lensing system is an early-type galaxy showing a strong [OII] emission line, and
produces 4 bright images of the distant background source.
It has an Einstein radius of , about 4 times large than the effective radius.
We perform a lensing analysis using both a Singular Isothermal Ellipsoid (SIE) and a
Peudo-Isothermal Elliptical Mass Distribution (PIEMD) for the lensing galaxy, and find that the final results
on the total mass, the dark matter (DM) fraction within the Einstein radius and the external shear due to a
foreground galaxy group are robust with respect of the choice of the parametric model and the
source redshift (yet unknown).
We measure the luminous mass from the photometric data, and find the DM fraction within the Einstein radius to
be between and , depending on the unknown source redshift.
Meanwhile, the non-null external shear found in our lensing models supports
the presence and structure of a galaxy group at , and an independent measurement of the 0.5-2 keV X-ray
luminosity within 20'' around the X-ray centroid provides a group mass of M,
in good agreement with the previous estimate derived through weak lensing analysis.
Finally, by inverting the HST/ACS I image with the lensing equation,
we obtain the reconstructed image of the magnified source galaxy, which has a scale of about 3.3 kpc at (2.7 kpc at )
and the typical disturbed disk-like appearance observed in low-mass star-forming galaxies at .
However, deep, spatially resolved spectroscopic data for similar lensed sources are still required to
detected the first stage of galaxy evolution, since the available spectrum shows no clear feature due to the background source
Solution strengthening and age hardening capability of Al-Mg-Mn alloys with small additions of Cu
No full textNine Al-(1-3)Mg-(0-0.4)Cu-0.15Si-0.25Mn (in wt%) alloys with potential applications in both packaging and automotive industries have been investigated. Tensile testing showed that solution strengthening is in good approximation linearly proportional to the Mg content. Mechanical testing and microstructural examinations of aged samples indicate that Mg2Si phase precipitates contribute to age hardening of Cu-free alloys, whilst both Mg2Si phase and S (Al2CuMg) phases contribute to that of Cu-containing alloys. The age hardening capability is critically influenced by solution treatment temperature: increasing the solution treatment temperature from 500 to 550ºC results in a marked increase in rate of hardening for Cu containing alloys and solution treatment at about 550ºC or higher is needed to allow Mg2Si phase precipitation during ageing in Cu-free alloys with Mg content of about 2% or higher
Pholcus kimi Song & Zhu 1994
No full textPholcus kimi Song & Zhu, 1994 (Figs. 21–22) Pholcus kimi Song & Zhu 1994: 37, f. 2A–D. Song, Zhu & Chen, 1999: 58, f. 24I–J. Zhang, Zhu & Song, 2004: 77, f. 1A–G. Diagnosis. Very similar to P. bidentatus, but can be distinguished from it by the shape of the tip of the procursus (Figs. 21F–G) and by the appendix without two thorn-shaped apophyses centrally (Fig. 21F). Redescription. Male: A specimen measured (Huangguoshu Waterfall), total length 6.1: cephalothorax 1.6 long, 1.7 wide; abdomen 4.5 long, 1.3 wide. Leg I: 47.7 (12.3+0.7+11.5+21.6+2.7), tibia II: 7.9, tibia III: 5.6, tibia IV: 7.2; tibia I L/D: 76. Prosoma shape as in Fig 21D. Carapace short, broad and almost circular, ochre, with pair of brown butterfly-shaped mark broadly connecting to ocular area. Cephalic region raised, with brown stripe centrally and two pairs of brown dots posteriorly, ocular area dark yellow. Clypeus 0.75, slightly ochre, with brown marks. Distance AME–AME 0.08. Diameter AME 0.09, ALE 0.21, PME 0.19, PLE 0.20. Chelicerae as in Fig. 21C, with pair of black serrated apophyses distally and two pairs of unsclerotized round apophyses proximolaterally. Labium light yellow. Endites yellow. Sternum almost dark ochre, without markings as in Fig. 21E. Femora, patellae and tibiae brown, with dark rings, metatarsi and tarsi brown. Tarsus with several pseudosegmentations as in Fig. 22E. Abdomen cylindrical, pale ochre, dorsum with numerous brown spots as in Fig. 21D. Venter pale brown, without marks. Male gonopore with four epiandrous spigots. Six spinnerets, ALS with six piriform gland spigots (Fig. 22H), and PMS with two spigots (Fig. 22I). Palps as in Figs. 21F and 21G, bulb with cleaver-shaped uncus, tip of appendix split into two parts, trochanter with short ventral apophysis. Palpal tarsal organ capsulate, on conical projection of cymbium (Fig. 22F). Variation. Body length in other males 5.4–6.3. Color of specimens from Huangguoshu Waterfall more pronounced than in the holotype. Female: in general very similar to male. Total length of bodies 5.6–7.2. A specimen measured (Huangguoshu Waterfall), total length 7.2, cephalothorax 1.3 long, 1.6 wide; abdomen 5.9 long, 2.1 wide. Tibia I: 6.4. Distance AME–AME 0.05. Diameter AME 0.10, ALE 0.21, PME 0.19, PLE 0.21. Tarsal organ capsulate on tarsus 1 as in Fig. 22A. Epigynum roughly triangular with swollen lateral edges as in Figs. 21A and 22B, a knob-shaped apophysis on the top. Dorsal view as in Fig. 21B, with a wavy sclerotized arch anteriorly and a pair of shoe-shaped pore plates. Distribution. Yunnan, Guizhou, Hunan, Hubei. Material examined. CHINA: Yunnan, Hekou County, collected from a cave, male holotype, 1♂ paratype, April 8, 1992, leg. M. S. Zhu (MHBU). Guizhou: Huangguoshu Waterfall, Anshun County, August 15, 2000, leg. J. X. Zhang, 1♂, 4♀ (MHBU); same data as above, but in October 1, 1997, 1♂, 4♀ (MHBU); Chishui County, Chishui Natural Reserve, May 27, 2005, leg. H. M. Chen, 3♂, 11♀ (MHBU); Daozhen County, Dashahe Natural Reserve, May 26, 2004, leg. H. M. Chen and Z. S. Zhang, 4♂, 7♀ (MHBU). Hunan: Chenzhou City, Wugaishan State Forest Farm, May 19, 2002, leg. J. Y. Yang and Z. S. Zhang, 1♂ (MHBU). Hubei: Badong County, Bashan Forest Park, August 20, 2003, leg. J. X. Zhang, 1♂, 1♀ (MHBU). Remark. The most important characters of this species are the conical projection of the cymbium and an arm-shaped procursus. Similar species, such as P. bidentatus and P. gui, are also distributed in southern China. We suggest they have a relatively close phylogenetic relationship.Published as part of Zhang, Feng & Zhu, Ming-Sheng, 2009, A review of the genus Pholcus (Araneae: Pholcidae) from China, pp. 1-114 in Zootaxa 2037 (1) on pages 43-47, DOI: 10.11646/zootaxa.2235.1.2, http://zenodo.org/record/531760
The Benefits of Being Economics Professor A (and not Z)
No full textAlphabetic name ordering on multi-authored academic papers, which is the convention in the economics discipline and various other disciplines, is to the advantage of people whose last name initials are placed early in the alphabet. As it turns out, Professor A, who has been a first author more often than Professor Z, will have published more articles and experienced afaster growth rate over the course of her career as a result of reputation and visibility. Moreover, authors know that name ordering matters and indeed take ordering seriously: Several characteristics of an author group composition determine the decision to deviate from the default alphabetic name order to a significant extent.performance measurement, incentives, economists, name ordering
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