摘要：The support for multiple video streams in an ad-hoc wireless network requires appropriate routing and rate allocation measures ascertaining the set of links for transmitting each stream and the encoding rate of the video to be delivered over the chosen links. The routing and rate allocation procedures impact the sustained quality of each video stream measured as the mean squared error (MSE) distortion at the receiver, and the overall network congestion in terms of queuing delay per link. We study the trade-off between these two competing objectives in a convex optimization formulation, and discuss both centralized and dis- tributed solutions for joint routing and rate allocation for multiple streams. For each stream, the optimal allocated rate strikes a balance between the selfish motive of minimizing video distortion and the global good of minimizing network congestions, while the routes are chosen over the least-congested links in the network. In addition to detailed analysis, network simulation results using ns-2 are presented for studying the optimal choice of parameters and to confirm the effectiveness of the proposed measures.

摘要：The bone regenerative scaffold with the tailored degradation rate matching with the growth rate of the new bone is essential for adolescent bone *** satisfy these requirement,we proposed bone tissue scaffolds with controlled degradation rate using osteoinductive materials(Ca-P bioceramics),which is expected to present a controllable biodegradation rate for patients who need bone *** properties,porosity,compressive strength and degradation properties of the scaffolds were studied.3D printed Ca-P scaffold(3DS),gas foaming Ca-P scaffold(FS)and autogenous bone(AB)were used in vivo for personalized beagle skull defect *** results indicated that the 3DS was highly vascularized and well combined with surrounding *** showed obvious newly formed bone *** showed the best repair effect,but it was found that AB scaffolds were partially absorbed and *** study indicated that the 3D printed Ca-P bioceramics with tailored biodegradation rate is a promising candidate for personalized skull bone tissue reconstruction.

摘要：In this paper, the topological pressure is preserved under some semi conjugates, and a formula of computing topological pressure by use of periodic points for positively expansive continuous map with specification is given.

摘要：This work investigates the performance of various forward error correction codes, by which the MIMO-OFDM system is deployed. To ensure fair investigation, the performance of four modulations, namely, binary phase shift keying(BPSK), quadrature phase shift keying(QPSK), quadrature amplitude modulation(QAM)-16 and QAM-64 with four error correction codes(convolutional code(CC), Reed-Solomon code(RSC)+CC, low density parity check(LDPC)+CC, Turbo+CC) is studied under three channel models(additive white Guassian noise(AWGN), Rayleigh, Rician) and three different antenna configurations(2×2, 2×4, 4×4). The bit error rate(BER) and the peak signal to noise ratio(PSNR) are taken as the measures of performance. The binary data and the color image data are transmitted and the graphs are plotted for various modulations with different channels and error correction codes. Analysis on the performance measures confirm that the Turbo + CC code in 4×4 configurations exhibits better performance.

摘要：Zinc-aluminum alloys have been used as bearing materials in the past. In recent years, binary Al-Zn alloys and Al-Zn-Cu alloys are being used as an alternative to the Zn-Al alloys for bearing applications. In this study, both binary Al-25 Zn and Al-3 Cu were prepared using stir casting process. Homogenization of the as-cast alloys was performed at 350oC for 8 h and then, the alloys were furnace-cooled to 50oC. The homogenization led to the removal of the dendritic structure of the as-cast alloys. After homogenization, wear parameters optimization was carried out using Taguchi technique. For this purpose, L9 orthogonal array was selected, and the control parameters selected are load, velocity, and sliding distance. The optimum parametric condition was obtained using signal-to-noise(S/N) ratio analysis, and specific wear rate(SWR) is the selected response. The "smaller-the-better" is the goal of the experiment for S/N ratio analysis. After the optimization, confirmation tests were carried out using analysis of variance(ANOVA) from the developed regression equation. Finally, wear mechanism studies were conducted using scanning electron microscopy(SEM) and energy-dispersive X-ray spectroscopy(EDX) images.

摘要：Gerotor pump is a special kind of internal rotary pump, which contains a trochoid profile (commonly called as cycloid). Generation of trochoid is normally realized by external rolling method, namely a circle rotating on a fixed circle without slipping. This paper proposes derivative process of the trochoid profile by means of internal rolling method, which is that internal surface of a circle contacts with a fixed circle and rotates around it without slipping. Moreover the instantaneous flow rate can be obtained by numerically calculating the change ratio of area between the inner and outer rotors in the outlet region of the gerotor pump, which avoids to complicatedly derivative process.

摘要：Objective:To investigate the changes in radial pulse induced by thermal stresses(TSs).Methods:Sixty subjects were *** an open-label,2x2 crossover randomization design,both feet of each subject were immersed in 15%:water for cold stress(CS)and in 40 X:water for heat stress(HS)for 5 min *** pulse,respiration and electrocardiogram(ECG)signals were recorded before,during and immediately after the ***:The an alysis of heart rate variability revealed that CS in creased the low-freque ncy(LF)and high-frequency(HF)components(P<0.05)and that HS reduced the LF and HF components(P<0.01).Both TSs reduced the normalized LF,increased the normalized HF,and reduced the LF/HF *** differences in the ECG signals were more dominant during the TS sessions,but those in the radial pulse signals became more domi nant immediately after the TS sessi *** decreased the pulse depth(P<0.01)and in creased the radial augme ntation in dex(P<0.1),and HS in creased the pulse pressure(P<0.1)and sube ndocardial viability ratio(P<0.01).There were no significant differences in pulse rate during the three time sequences of each *** respiration rate was increased(P<0.1),and the pulse rate per respiration(P/R ratio)was significantly decreased(P<0.05)with *** HF region(10-30 Hz)of the pulse spectral density was suppressed during both ***:CS induced vasoconstriction and sympathetic reactions,and HS induced vasodilation and parasympathetic reacti *** on defi nitions used in pulse diag no sis,we made the novel discoveries that the pulse became slower(decreased P/R ratio),more floating and tenser under CS and that the HF region of the spectral power decreased significantly under both TSs.

摘要：From 1980’s decade,the introduction of carbon composite materials in structural applications has been consistently increased in the successive generations of civil aircraft from Single Aisle to Middle-long Range to achieve a culminant point with more than 50%in structure weight in recent commercial civil *** evolution,done through successive iterations,has been possible by combining in the same time the improvement of intrinsic composite material performances and its transformation into prepreg production technologies together with the development of new manufacturing process for material lay-up automation at composite shop-floor manufacturer of aircraft composite *** challenges are still coming to continuously develop materials and technologies in order to pursue the production more cost-effective composite *** to higher aircraft production rate for single aisle,new challenges may force material and aircraft designers and producers to furthermore drive new products and processes introduction and new ways of transformation within in next decade of composite aircraft *** propose to illustrate these trends using past and recent developments and our return of experience from Hexcel on Civil Aircraft programs.

摘要：We generalized an constructing method of noncoherent unitary space time codes (N-USTC) over Rayleigh flat fading channels. A family of N-USTCs with T symbol peroids, M transmit and N receive antennas was constructed by the exponential mapping method based on the tangent subspace of the Grassmann manifold. This exponential mapping method can transform the coherent space time codes (C-STC) into the N-USTC on the Grassmann manifold. We infered an universal framework of constructing a C-STC that is designed by using the algebraic number theory and has full rate and full diversity (FRFD) for t symbol periods and same antennas, where M, N, T, t are general positive integer. We discussed the constraint condition that the exponential mapping has only one solution, from which we presented a approach of searching the optimum adjustive factor αopt that can generate an optimum noncoherent codeword. For different code parameters M, N, T, t and the optimum adjustive factor αopt, we gave the simulation results of the several N-USTCs.

摘要：The paper gives a thorough survey of the studies of different authors in the field of domestic hot water (DHW) consumption and consumption profiles. It presents an overview of the research done into DHW by the Tallinn University of Technology. Working out on the basis of investigations has been new empirical formulas for determining design flow rates for schools, kindergartens, office buildings and shopping centres. DHW consumption profiles of typical buildings are presented. Comparisons are given on the determination of DHW design flow rates by the standard EVS 835, the EN 806-3 and the recommended formulas. The latter makes it possible to considerably decrease the design flow rates which in turn enables to deminish the load of the equipment, to improve the quality of control and to decrease the diameters of the pipes of the district heating network and the losses of heat in them.