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1

A Provably Secure Anonymous Two-Factor Authenticated Key Exchange Protocol for Cloud Computing

Wei F., Zhang R., Ma C

Fundamenta Informaticae

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2018

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Vol. 157, nr 1/2

201--220

EN

Two-factor authenticated key exchange (TFAKE) protocols are critical tools for ensuring identity authentication and secure data transmission for cloud computing. Until now, numerous TFAKE protocols based on smart cards and passwords are proposed under this circumstance. Unfortunately, most of them are found insecure against various attacks. Researchers focus on cryptanalysis of these protocols and then fixing the loopholes. Little attention has been paid to design rationales and formal security models of these protocols. In this paper, we summarize the security requirements and put forward a formal security model for TFAKE protocols for cloud computing. We then present an efficient TFAKE protocol without using expensive asymmetric cryptology mechanisms to achieve high efficiency. Our protocol can be proven secure in the random oracle model and achieves user anonymity. Compared with other TFAKE protocols, our protocol is more efficient and enjoys provable security.

2

The analysis of urban taxi carpooling impact from taxi GPS data

Xiao Q., He R., Ma C.

Archives of Transport

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2018

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Vol. 47, iss. 3

109--120

EN

Taxi is an important part of urban passenger transportation system. The research and analysis of taxi trip behavior is the key to meet the demand of urban passenger transport and solve the traffic congestion problem. Based on the GPS data of taxis in Nanjing, the statistical method is used to analyze the taxi characteristics of the average number of passengers, the average passenger time, the no-load distance and the passenger distance. By using the double logarithmic coordinate, the trip distance and trip time of taxi passengers are analyzed, it is found that the average trip distance of taxi passengers is mainly concentrated in 3-20 km, and the average trip time of taxi passengers is mainly concentrated in 10-30 minutes. Using the information entropy theory to construct the equilibrium model of taxi passenger-carrying point, and analyze the spatial distribution of taxi, it is found that the distribution of urban taxi is unbalanced. The peak clustering algorithm is used to determine the location of passenger gathering points, and the hot spot of taxi trip is analyzed, it is found that the hot spots of taxi trip are mainly concentrated in the central city of Nanjing. Combined with the results of urban taxi trip analysis, from the perspective of taxi and passenger, we found that the number of urban taxis, the passenger carrying rate of taxis, the duration period of passenger trip, the duration and distance of passenger trip and the location of passenger trip points will have an impact on the urban taxi carpooling in Nanjing. By using the probability model of urban taxi carpooling, this paper discusses and analyzes the influence of these factors on urban taxi carpooling. The research in this paper can provide a reference for the effective implementation of urban taxi carpooling policy.

3

Evaluation of Strength and Failure of Brittle Rock Containing Initial Cracks under Lithospheric Conditions

Li X., Qi C., Shao Z., Ma C.

Acta Geophysica

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2018

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Vol. 66, no. 2

141--152

EN

Natural brittle rock contains numerous randomly distributed microcracks. Crack initiation, growth, and coalescence play a predominant role in evaluation for the strength and failure of brittle rocks. A new analytical method is proposed to predict the strength and failure of brittle rocks containing initial microcracks. The formulation of this method is based on an improved wing crack model and a suggested micro-macro relation. In this improved wing crack model, the parameter of crack angle is especially introduced as a variable, and the analytical stress-crack relation considering crack angle effect is obtained. Coupling the proposed stresscrack relation and the suggested micro-macro relation describing the relation between crack growth and axial strain, the stress-strain constitutive relation is obtained to predict the rock strength and failure. Considering different initial microcrack sizes, friction coefficients and confining pressures, effects of crack angle on tensile wedge force acting on initial crack interface are studied, and effects of crack angle on stress-strain constitutive relation of rocks are also analyzed. The strength and crack initiation stress under different crack angles are discussed, and the value of most disadvantaged angle triggering crack initiation and rock failure is founded. The analytical results are similar to the published study results. Rationality of this proposed analytical method is verified.

4

Effects of Heat Treatment on the Mechanical and Thermal Performance of Fabric Used in Firefighter Protective Clothing

Cui Z, Ma C, Lv N

Fibres & Textiles in Eastern Europe

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2015

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Vol. 23, no. 2 (110)

74--78

EN

With excellent thermal stability and resistance, X-fiper® fabric has been applied in firefighter protective clothing. In this paper, X-fiper® fabric was subjected to heat treatment at 6.5 kW/m2 and 9.7 kW/m2 for durations between 0 to 30 min. Effects of the heat intensity and exposure duration on mechanical properties, thermal protective performance, surface morphology, and structural properties were studied and analysed. The results showed that the intensity of heat flux had significant effects on the tensile strength, elongation at break, and tear strength. The tear strength of X-fiper® fabric was less than 100 N after 5-minute’s exposure at 300 °C. The thermal protective performance, however, did not change considerably. From the scanning electron microscope (SEM) analysis, specimens showed grooves, peel-offs and deposits as a result of heat treatment. The results observed by SEM and FTIR-Raman spectroscopy revealed the mechanisms of changes in mechanical properties and thermal protection.

PL

W odzieży ochronnej strażaków zastosowano tkaninę X-fiper®, która charakteryzuje się doskonałą odpornością i stabilnością termiczną. W prezentowanej pracy tkaninę tę poddano działaniu energii cieplnej 6,5 kW/m2 i 9,7 kW/m2, w czasie od 0 do 30 min. Badano i analizowano wpływ intensywności i czasu trwania ekspozycji cieplnej na właściwości mechaniczne, zdolność ochrony przed efektem cieplnym, morfologię powierzchni i właściwości strukturalne. Wyniki pokazują, że intensywność strumienia ciepła ma znaczący wpływ na wytrzymałość na rozciąganie, wydłużenie przy zerwaniu i wytrzymałość na rozrywanie. Wytrzymałość na rozrywanie tkaniny była mniejsza niż 100N po 5 minutach ekspozycji w temperaturze 300 °C. Jednakże, zdolność ochrony przed efektem cieplnym nie zmieniła się znacząco. Na zdjęciach SEM powierzchni próbek widoczny jest peeling i bruzdy oraz inne zmiany strukturalne. Wyniki obserwacji SEM i spektroskopii FTIR-Ramana pozwalają na określenie mechanizmu zmian właściwości mechanicznych i termicznych próbek.

5

Synthesis, Characterization and Crystal Structures of Diorganotin(IV) Complexes with 2-Mercapto-4-methyl-5-thiazoleacetic Acid

Zhang R., Sun F., Ma C., Zhang J.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 3

367-376

EN

The organotin(IV) complexes, [(C4H4NS2CH2CO2)R2Sn(OMe)OSnR2]2 (R =Me1, n-Bu 2, Ph 3, PhCH2 4), have been synthesized and characterized by IR and 1H NMR spectroscopy. The structures of 1 and 2 have also been determined by X-ray crystallography. The structure analyses show that both complexes 1 and 2 feature a centrosymmetric core arranged as a ladder. Links between pairs of tin atoms are afforded by mi2-methoxo groups and each carboxylate anion coordinates an exocyclic tin atom exclusively, in the monodentatemode.Moreover, the packing of complexes 1 and2 are stabilized by the hydrogen bonding interactions.

6

Synthesis and Crystal Structure of Five-Coordinated Triorganotin Complexes with 2,5-Dimercapto-4-phenyl-1,3,4-thiodiazole

Zhang R., Li F., Li K., Ma C.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 6

753-760

EN

Reactions between triorganotin chloride and 2,5-dimercapto-4-phenyl-1,3,4- thiodiazole gave complexes R3Sn(S3N2C8H5) (4: R = Ph; 5: R = PhCH2 and 6: R = n-Bu), respectively. All products were characterized by elemental analysis, IR, 1H NMR, 13C NMR, and two of them ((4) and (5)) have been determined by X-ray crystallography. Including the Sn-N interaction, the tin atoms of three complexes all have five-coordinated distorted trigonal bipyramidal geometry. All three complexes have antitumor activity in bioactivity measurements. Crystal data for complex (4): monoclinic, space group P2(1)/c, a = 9.696(2)A,b = 14.773(3) A, c = 17.466(4)A, _ = 92.599(3)_, and Z= 4. Crystal data for complex (5): triclinic, space group P-1, a = 9.744(6) A, b = 16.338(10) A, c =17.957(12) A, _ = 90.000(12)_, _ = 100.735(11)_, _ = 90.000(12)_ and Z = 4.