检索结果-南通市图书馆

11-Round Impossible Differential Algebraic Attack for Serpent Encryption Algorithm

在线全文

学校读者我要写书评

暂无评论

wuhan university Journal of Natural Sciences 2010年第3期15卷 232-236页

作者： HU Zhihua1,2, QIN Zhongping3.1. School of Computer, wuhan university, wuhan 4.0072. Hubei, {3. 2. college of Mathematical and Information Sciences,Huanggang Normal university, Huanggang 43.000, Hubei, {3. 3. School of Software Engineering, Huazhong university of Science and technology, wuhan 43.074, Hubei, {3. School of Computer Wuhan University Wuhan Hubei China college of Mathematical and Information Sciences Huanggang Normal University Huanggang Hubei China School of Software Engineering Huazhong University of Science and Technology Wuhan Hubei China

This paper explored algebraic features of nonlinear parts in Serpent encryption algorithm and offered an 11-round Serpent-128 impossible differential algebraic attack through utilizing the method in constructing S-box algebraic equations. The new method analyzed block ll-round Serpent with 2127 selected plaintexts and 2-29 bytes memory space at the same time of giving a new design principle of S-box anti-algebraic attack.

关键词： impossible differential Serpent algebraic equation

A novel method of systematic error compensation for a position and orientation system

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2008年第8期18卷 953-963页

作者： Xiuxiao Yuan* School of Remote Sensing and Information Engineering, wuhan university, wuhan 43.079, china School of Remote Sensing and Information Engineering Wuhan University Wuhan 430079 China

A novel method is introduced for self-calibration and elimination of systematic errors for a position and orientation system (POS). The method uses a combined bundle block adjustment with POS data (named the POS-supported bundle block adjustment) without a calibration field. On the basis of delivering strict observation equations for POS data, the specific scheme of compensating the translation and drift systematic errors in a POS is given, and a prototype system WuCAPS is developed. The effects of eliminating POS systematic errors using the POS-supported bundle block adjustment for different ground control conditions are tested using two sets of actual aerial photos. The first set was taken over a flat region in the suburbs of the city of Yingkou in china and tested at a scale of 1:2500. The second set was taken over a high mountainous region in the desert region of Xinjiang in china and tested at a scale of 1:3.,000. The empirical results verified that the POS systematic errors can be completely eliminated and the photo elements of exterior orientation obtained by the POS-supported bundle block adjustment can satisfy the requirements of aerial photogrammetric topographic mapping when four full ground control points (GCPs) are emplaced in the corners of the adjustment block for large-scale images of flat regions, but only one full GCP emplaced in the center of the adjustment block is needed for medium-small scale images of mountainous regions. This not only demonstrates the validity of the established mathematical model and the feasibility of the method proposed in this paper, but also avoids the use of a special calibration field. Therefore, it can simplify the existing POS operation rules and dramatically save on practical application costs, laying the theoretical foundation for widespread use of POS.

关键词： Position and orientation system (POS) Systematic error POS-supported bundle block adjustment Self-calibration Accuracy

A delay differential equation solver based on the parallel Adams algorithms

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Communications in Nonlinear Science and Numerical Simulation 2001年第1期6卷 28-34页

作者： Chengjian ZHANG and Hongbing YU(Department of Mathematics, Huazhong university of Science and technology, wuhan 43.074,{3.) Department of Mathematics Huazhong University of Science and Technology Wuhan 430074 China

This paper constructs a class of parallel Adams algorithms for the systems of delay differential equations. The results on convergence and stability are given. The theoretical analysis and numerical test shows that th... 详细信息

关键词： parallel algorithms Adams algorithms delay differential equations

METHOD TO SOLVE ELASTIC CONJUGATE SURFACES IN MULTI-TEETH MESHING

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2002年第4期15卷 348-352页

作者： Yi ChuanyunSchool of Mechanical Science and Engineering, Huazhong university of Science and technology,wuhan 43.074, {3. School of Mechanical Science and Engineering Huazhong University of Science and Technology Wuhan 430074

A method to solve the elastic conjugate surfaces in multi-teeth meshing ispresented. In mechanical manufacturing and design, there exist a lot of problems relating toconjugate surfaces, such as three-dimensional engagement, steel rolling and workpiece machining,which cause great effects on the quality of machining and performances of transmission. This methoddescribes relation between conjugate motion and elastic deformation in the process of mesh-in andmesh-out, and can be used to determine the profile of gear tooth by a certain given load sharing.

关键词： multi-teeth meshing elastic conjugate surfaces

STUDY ON PCT CURVE FOR Zr-Ni HYDROGEN STORAGE AMORPHOUS ALLOY

在线全文

学校读者我要写书评

暂无评论

Journal of wuhan university of technology(Materials Science) 1999年第4期14卷 53-56页

作者： ZHANG Dongming FU Zhengyi wuhan university of technology wuhan university of technology China State Key Lab Adv. Technol. Mat. S. Wuhan University of Technology Wuhan 430070 China

Based on the comprehensive analysis of hydrogen storageexperimental results for Zr-Ni amor- phous alloy, the quantitativerelationship of PCT curve was established, the calculated results areconsistent with experimenta... 详细信息

关键词： quantitative relationship PCT curve amor phous alloy

ELECTRO-THERMAL EFFECTS AND DEFORMATION RESPONSE OF CARBON FIBER MAT CEMENT BEAMS

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2003年第4期16卷 359-365页

作者： Zhu Sirong Li Zhuoqiu Song Xianhui (Department of Engineering Structures and Mechanics,wuhan university of technology,wuhan 43.070,china) Department of Engineering Structures Wuhan University of Technology Wuhan 430070 China

A carbon fiber mat is a sheet composed of intercrossing short carbon fibers,which has more stable and lower electrical resistivity compared with dispersed short carbon fiber mixed in *** carbon fiber mat cement could exhibit obvious electro-thermal *** electrified,the temperature of composite structures made up of cement mortar and carbon fiber mat will rise *** the temperature field is not uniform,temperature difference will cause structures to deform,which can be used to adjust the deformation of *** temperature field and deformation response driven by the electro-thermal effects of a type of carbon fiber mat cement beams are ***,the temperature and deformation responses are studied using theories of thermal conduction and ***,experimental results are given to verify the theoretical *** two parts lay the foundation for temperature and deformation adjustment.

关键词： carbon fiber mat cement electro-thermal effect deformation response

The Influence of Additives on Crystallization of Polyvinyl Chloride

在线全文

学校读者我要写书评

暂无评论

Journal of wuhan university of technology(Materials Science) 2007年第2期22卷 271-275页

作者：刘亚群张超灿 Institute of Materials Science and Engineering Wuhan University of Technology

Acetanilide, adipic acid and potassium hydrogen phthalate were chosen as nucleating agents of polyvinyl chloride（PVC）, and their effects on PVC crystallization were studied by differential scanning calorimetry, wide angle X-ray diffraction and fourier transform infrared spectroscopy. The experimental results indicate that all of the three additives are compatible with PVC to some extent, but adipic acid＇s compatibility with PVC is less satisfactory. The three additives can improve PVC crystallinity, and acetanilide can decrease PVC glass transition temperature（T）and narrow PVC melting range, while adipic acid and potassium hydrogen phthalate rise T of PVC and widen its melting range. All additives do not affect PVC crystal system and all g samples are in orthorhombic system. All additives can improve （200）, （110）, （210） and （201, 111） planes growing. Moreover, acetanilide and adipic acid can shrink PVC spacings and improve the crystal perfection of PVC, but potassium hydrogen phthalate swells spacings and reduces the perfection of PVC crystal.

关键词： polyvinyl chloride crystalline structure differential scanning calorimetry wide angle X-ray diffraction

LAMINATED VISCOELASTIC PLATE WITH INCLUSIONS FOR PASSIVE UNDER-WATER ACOUSTIC CONTROL

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2002年第1期15卷 23-29页

作者： Zhao Hanzhong (Department of Mechanics,Huazhong university of Science and technology,wuhan 43.074,{3.) Department of Mechanics Huazhong Univ. of Sci. and Technol. Wuhan 430074 China

The effectiveness of a fluid-loaded sandwiched viscoelastic layerin suppressing acoustic scat- tering and radiation has been estimatedusing the Thomson-Haskell matrix method. The GU (Gaunaurd andUberall) resonance theory has been adopted to handle three types ofviscoelastic substrates with air -filled in- Clusions. The effects ofthe varying thickness of the substrates, the volume fractions of theinclusions and fre- Quencies of incident waves have been studied todetermine the optimal strategies of signal reduction. In theInvestigation, the monopole resonance phenomena of the inclusionshave been taken into account.

关键词： underwater acoustic control laminated viscoelastic plate air-filledinclusion

Electronic Structure and Thermoelectric Properties of Na and Ni-doped Ca_3.o_2O_6

在线全文

学校读者我要写书评

暂无评论

Journal of wuhan university of technology(Materials Science) 2006年第3期21卷 94-96页

作者：闵新民 Department of Applied Chemistry Wuhan University of Technology Wuhan 430070 ChinaState Key Laboratory of Advanced Technology for Materials Synthesis and ProcessingWuhan University of Technology Wuhan 430070China

The electronic structures of Ca3.o2O6, Na and Ni doped models were studied by the quantum chemical software of Cambride Serial Total Energy Package （CASTEP） that is based on deusity function theory （DFT） and psendo-potential. The electronic conductivity, seebeck coefficient, thermal conduetivity and figure of merit （Z） were computed. The energy band structure reveals the form of the impurity levels due to the substitutional imapurity in semiconductors. Na-doped model stunts the character of p-type semiconductor, but Xi-doped model is n-type semiconductor. The calculation results show that the electric conduetirity of the doped model is higher than that of the non-doped model, while the Seebeck coefficient and thermal conductivity of the doped model are lower than those of the non-doped one. Because of the great increase of the electric conductivity, Z of Na- doped model is enhanced and thermoelectric properties are improved. On the other hand, as the large decline of Seebeck coefficient, Z of Ni-doped model is less than that of the non-doped model.

关键词： cobalt oxide substitutional impurity quantum chemical calculation electronic structure thermoelectric property