191,853 research outputs found
A rearrangement of azobenzene upon interaction with an aluminum(I) monomer LAl {L = HC (CMe)(NAr)(2 ), Ar=2,6-iPr(2)C(6)H(3)
No full textReaction of LA1 (1) or [LA1{eta'-C-2(SiMe3)(2)}] (2) (L = HC[(CMe)-(NAr)](2), Ar = 2,6-iPr(2)C(6)H(3)) with azobenzene affords a five-membered ring compound [LA1{N(H)-o-C6H4N(Ph))}] (3). In the formation of 3 a three-membered intermediate [LA1(eta(2)-N2Ph2)] (A) is suggested by a [1 + 2] cycloaddition reaction; A is not stable and further rearranges to 3. DFT calculations on similar compounds with modified L' (L' = HCl(CMe) (NPh)](2)] show that the complexation energy of the reaction of L'Al with azobenzene to form [L'A1(eta(2)-N2Ph2)] is about -39 kcal mol(-1), and the best estimate of the energy difference between [L'A1(eta(2)-N2Ph2)] and [L'A1{N(H)-o-C6H4N(Ph))] is -76 kcal mol(-1). (c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005
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
Using performance assessment in secondary school mathematics: an empirical study in a Singapore classroom
No full textThis article reports an exploratory study on using performance assessment in mathematics instruction in a high-performing secondary school in Singapore. An intact mathematics class participated in the study, and received chapter-based performance tasks as intervention during regular mathematics lessons for about one and a half school years. The performance tasks used included authentic and/or open-ended tasks. The students’ academic achievements and attitudes in mathematics were compared with a comparison class that did not receive the intervention. Both quantitative and qualitative data were collected, mainly through questionnaire surveys, performance task tests, conventional school exams, and interviews with students and teachers. The results suggest that the students receiving the intervention performed significantly better than their counterparts in solving conventional exam problems, and in general they also showed more positive changes in attitudes towards mathematics and mathematics learning. The students from the experimental class also expressed positive views about the benefits of using performance tasks in promoting their ability in higher order thinking, though no statistically significant difference was detected between the two classes of students in solving unconventional tasks before and after intervention. Overall, the results appear to support teachers’ using contextualised problems in real life situations and open-ended investigations in students’ learning of mathematic
ljt-uiuc/H-k-c: H-k-c
No full textH-k-c package:
Generalized H-k after harmonic correction on receiver functions
a modification of H-k method by Zhu and Kanamori (2000)
by Jiangtao Li, Xiaodong Song, Pan Wang, and Lupei Zhu
Reference: Li, J., Song, X., Wang, P., & Zhu, L. (2019). A generalized H-k method with harmonic corrections on Ps and its crustal multiples in receiver functions. J. Geophys. Res. Solid Earth, 124(4), 3782-3801
Contact: [email protected]; [email protected]
Replication Data for "A Validation Study For A Bat-Inspired Sonar Sensing Simulator"
No full textThis dataset is used in the manuscript entitled "A validation study for a bat-inspired sonar sensing simulator" by H. Zhu, A. K. Gupta, X. Wu, M. Goldsworthy, R. Wang, M. Mikkilineni and R. Mueller. It contains the impulse response signals from experiments and simulation after all preprocessing and alignment steps. This data is used to produce statistics and plots in the manuscript
Bothropolys edgecombei Ma, Song & Zhu 2008
No full textBothropolys edgecombei Ma, Song & Zhu, 2008 Bothropolys edgecombei Ma, Song & Zhu, 2008 d: 252, Figs 2 a–h Previous records. Sichuan Province (Aba City) (Ma et al., 2008 d). Remarks. Only known from China.Published as part of Ma, Huiqin, Pei, Sujian, Hou, Xiaojie, Zhu, Tiegang, Wu, Dayong & Gai, Yonghua, 2014, An annotated checklist of Lithobiomorpha of China, pp. 333-358 in Zootaxa 3847 (3) on pages 352-353, DOI: 10.11646/zootaxa.3847.3.2, http://zenodo.org/record/23128
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
Performance Evaluation of Distributed-Antenna Communications Systems Using Beam-Hopping
No full textDigital beamforming (DBF) techniques are capable of improving the performance of communications systems significantly. However, if the transmitted signals are conflicted with strong interference, especially, in the direction of the transmitted beams , these directional jamming signals will severely degrade the system performance. In order to efficiently mitigate the interference of the directional jammers, in this contribution a beam-hopping (BH) communications scheme is proposed. In the proposed BH communications scheme, only one pair of the beams is used for transmission and it hops from one to the next according to an assigned BH pattern. In this contribution a range of expressions in terms of the average SINR performance have been derived, when both the uplink and downlink are considered. The average SINR performance of the proposed BH scheme and that of the conventional single-beam (SB) as well as multiple-beam (MB) assisted beam-processing schemes have been investigated. Our analysis and results show that the proposed BH scheme is capable of efficiently combating the directional jamming, with the aid of utilizing the directional gain of the beams generated by both the transmitter and the receiver. Furthermore, the BH scheme is capable of reducing the intercept probability of the communications. Therefore, the proposed BH scheme is suitable for communications, when several distributed antenna arrays are available around a mobile
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