Abstract:An efficient and precise retinal vessel centerline extraction approach based on ridge detection is proposed. Firstly, the candidate retinal vessel centerline is obtained by using ridge detection. Then, illumination equalization and the multi-scale morphological enhancement are applied. Finally, the Otsu dual threshold segmentation method and Otsu single threshold segmentation method are respectively applied to the enhanced image for each scale in the retina ROI. The final vessel centerline is obtained with logic AND operation between the candidate centerline and the summation of segmentation results of each scale. The proposed method is evaluated by using database of 25 fluorescein retinal images and some color retinal images. The experiments demonstrate the method can extract the slim vessels and low contrast vessels well, while persevering vessels connectivity well. The extracted vessels are compared with the skeleton of the manual vessel image, and the average overlap rate is 83.5%. The proposed method outperforms the Hoover algorithm and conservatively hand-labeled method for the small vessels extraction and connectivity.

Abstract:Serpentine radiant heat transfer pipes(SRHTP)are expensive and with low heat exchanged, so the heat transfer panel with capillary imbibition core (HTPCIC) is put forward. HTPCIC is composed by potassium citrate-plaster (PCP), and PCP board becomes a uniform channel of which the flow rate is 55.3% when water is cooling medium. By changing the emissivity of HTPCIC' surface(low emissivity 0.23，high emissivity 0.95)and the temperature of cold-water(7~18 ℃), at 26 ℃ (±1 ℃), heat transfer characteristics of HTPCIC are analyzed whose average pore radius is 0.015 mm and porosity is 55.3%. The experimental results show that the cooling capacity of HTPCIC meets the requirements of conventional radiation air-conditioning, and compared with SRHTP, the initial cost reduces by 80%. Moreover, regression equation of the HTPCIC heat transfer guideline is proposed: Nu=0.029Re0.21Pr2.6θ0, which provides basis for establishing a complete design theory.

Abstract:The stability analysis is one of the important problems in the traffic flow theory, where the congestion phenomena can be regarded as the instability and the phase transition of a dynamical system. An extended optimal velocity model is deduced by considering the effect of the information of two leader cars. The stability condition of the extended model is obtained by using the linear stability theory. The modified Korteweg-de Vries (mKdV) equation is derived to describe the traffic behavior near the critical point by applying the nonlinear analysis. The numerical simulation results demonstrate the analytical results and show that the traffic congests are suppressed more efficiently by considering two vehicles ahead. Therefore, the next-nearest-neighbor car has strong effects on traffic dynamics and plays an important role on stabilizing the traffic flow.

Abstract:Micro-coil array and matching capacitors together can realize the parallel transmission of multichannel signal. In order to improve the accuracy and reliability of receiving information from each channel and to reduce the size of implant systems, two kinds of micro-coil arrays fabricated by using PCB (printed circuit board) and FPC (flexible printed circuit) technology respectively are presented. Then the two micro-coil arrays are used in multi-channel transmission device with a 2 * 2 array. The coupling efficiency of two kinds of process coils under ideal coupling, spatial mismatch as well as different load conditions are tested. The results show that two kinds of coils are affected by spatial mismatch. However, if the transverse mismatch is restricted less than 3 mm and the angular mismatch is less than 30°, the two kinds of coils can be used for signal transcutaneous transmission for implantable electrical stimulation devices at the laboratory stage, and the channel output signal can meet the requirements of electrical nerve stimulation. As for the reliability of the system, FPC coil shows more advantages, and it is more adapted to implantable system. 

Abstract:In order to get wind load and wind induced response of super tall buildings in hilly terrain wind field, effect of changing of turbulent intensity on wind loads must be known. 4 kinds of turbulent wind field are simulated, and 3 super tall building models with round section of different aspect ratio are manufactured. Effects of turbulent intensity, aspect ratio and layer height on along-wind and across-wind load are discussed. Different models are used in fitting of wind load spectrum on each direction. Parameters of load spectrum models are secondary fitted based on turbulent intensity and aspect ratio. Mathematical models of wind load spectrum of super tall buildings with round section in hilly terrain are preliminarily established. At last, an example is provided. According to vertical profile of mean velocity, turbulent intensity and mathematical model of wind load spectrum, wind induced dynamic response of super tall buildings in hilly terrain and flat terrain are compared.

Abstract:The performance of a parallel and distributed system heavily depends on the effectiveness of the underlying interconnection network. Honeycomb networks are promising candidates for interconnection networks in parallel and distributed applications. This paper addresses the hamiltonicity of a hexagonal honeycomb torus (HHT) with a pair of faulty nodes lying diagonally on a cycle of length 6. We show that such a faulty HHT is hamiltonian by presenting a systematic method for constructing a fault-free hamiltonian cycle. This result reveals another appealing fault-tolerant feature of HHTs.

Abstract:The introduced resonant accelerometer makes use of the equivalent electrostatic stiffness to sense the acceleration. The sensitivity can be adjusted by changing the applied sensing voltage and it is robust for the fabrication error. According to the sensing principle，the dynamic model of the single beam accelerometer is built along with the no-linear relationship of the output frequency and the displacement of all positive components. When the stiffness of the vibrating beam is much bigger than the stiffness of the fold beam, the sensitivity can effective achieve. It is the restriction for the structure design. For the differential structure, mode analysis shows it is a lower mode in plane for the work mode. Decreasing the stiffness of connected end for the double vibrating beam can reduce the disturbance error. The bulk micromachining for the resonant accelerometer can achieve high depth width ration etching. The experiment find the structure is not broken and there is the same frequency disturbance problem. FM is suggested to deal with the disturbance. Theory analysis and test provides some important conclusions for the design of the novel type resonant accelerometer.

Abstract:Patient monitoring in the operating theatre requires a high level of vigilance by anesthetists. The aim of this paper is to report the design of a clinically useful diagnostic system called real-time smart alarms for absolute hypovolemia in anesthesia monitoring (RTSAAM). The system provides decision support to the anesthetist by presenting the diagnostic results on an integrative, ergonomic display that is hoped to enhance patient safety. The performance of the system is assessed by both offline testing and real-time testing in the operation theatre. When detecting absolute hypovolemia (AHV) a satisfactory level of agreement (up to 81%) is observed between RTSAAM and the anesthetist.

Abstract:The mesh stiffness of gear tooth is simulated by spring elements, the connected bolt between various housings are simplified as bar elements, and the sliding bearing and rolling bearing are simplified as spring dumping elements. Based on them, the gear-shaft-bearing-housing coupled finite element model and boundary element model of GWC6066 marine gearbox are established. Finally, the dynamic response under internal dynamic excitation is analyzed and the vibration severity, structural-borne noise and air-borne noise of the gear system are forecasted. Through the experimental modal analysis of gear system, and the test of vibration response and air pressure, the natural frequencies, vibration severity, structural-borne noise and air-borne noise are obtained. Compared with numerical results, two results show good agreement.

Abstract:Many subsystems in CNC machine tool have only a few failures, so they are small samples. In this case, classical reliability modeling method often has large errors. For the failure data of small sample, maximum likelihood estimation method is used to estimate the Weibull distribution model parameters of time between failures of the subsystems. Then, the Weibull distribution model parameters are modified by parameter bias correction method. Finally, the effect of bias correction parametersis tested by the D test and the error area ratio test method. The test results show that the modified models are better.

Abstract:The advantage of blade-offset rotary vane compressor is analyzed, and its kinematic model is established through simplifying the vane motion to the circle center movement of the main vane arc by using equidistant curve envelope principle. Then, the relationship between the displacement, velocity, acceleration of blade and the angle of rotor is obtained. Finally, based on the theory obtained, the simulation is also carried out. Results show this method can avoid complex process for finding the contact point, which meanwhile has good solving accuracy. Because of the differences on kinematic characteristics, the blade kinematic analysis for blade-cardiac cannot be simply used for the blade-offset one, and the kinematic and dynamic characteristics of cylinder profile cannot be shown by the simplified analysis. However, the scientific theory calculation method for the kinematic analysis of blade-offset rotary vane compressor put forward provides a reliable theoretical basis for the innovation of multi-stage combination cylinder profile with high volumetric efficiency and compression ratio, and also broadens the design theory of the rotary vane compressor.

Abstract:On the basis of studying the accurately identification algorithm of planar target and transformation model of the space vector, the imaging target models and spatial attitude measurement models are established. Then, a new topological positioning method is put forward. Finally, the four-wheel location measurement is given as an example. The results demonstrate that the method has better anti-interference and higher measurement precision, which provides a feasible method for a machine vision measurement system by using the plane target.

Abstract:According to the urgent need for motorcycle parts enterprise to improve the ability of information exchange and business collaboration between the production process and other links such as the marketing, design, production planning, outsourcing, purchasing and delivering, an integration framework of the intergraded workshop production management system for motorcycle parts enterprise is presented. It can be integrated with the designing and production planning management systems upwards, the workshop equipments and workers downwards, and the subcontract production and supply chain management systems outwards. Then, some key technologies are studied, such as the realization scheme of system integration based on Service Oriented Architecture (SOA), the data integration and sharing mechanism of heterogeneous information system based on eXtensible Markup Language (XML), and the real-time interaction technology of workshop information based on the multi-functional interactive information terminals, etc. Finally, the system is developed and successfully applied in a motorcycle parts enterprise, and good results are obtained.

Abstract:The properties and cutting performance of partial sintered Y2O3-stabilized tetragonal zirconia polycrystal (Y-TZP) have been introduced. Then, the CAD/CAM technological chain in the field of dental restoration, the basic grinding theory and technical equipment which are necessary for dental restoration have also been analyzed. Finally, an example for grinding molar crown using partial sintered zirconia has been provided, the specific processing are divided into two steps:1)using standard cylindrical dental diamond burs which is Ф1.6 mm to fabricate the molar crown with grinding parameters(spindle speed 40 000 r/min, grinding depth 0.2 mm, feed rate 300 mm/min)that have high material removal rate;2)using dental diamond burs with ball-end cone wheel, whose diameter is 0.8 mm, with spindle speed 40 000 r/min, grinding depth 0.06 mm, feed rate 100 mm/min, to fine grinding the surface of molar crown. After processing, the surface quality of the molar crown has been tested high and is consistent with the requirements of dental restoration.

Abstract:The Dynamic Voltage Scaling(DVS)technology which is widely used in numerous energy management schedule has negative effect on system reliability. Based on the artificial bee colony algorithm (ABC), two noble reliability-aware schedule algorithms are proposed for DVS systems with discrete frequencies, which will meet the energy constraint and deadline naturally while maximize the reliability of the system. The simulation results indicate that the dynamic schedule algorithm outperforms the static schedule algorithm, and its performance is close to that of the optimal scheduler that knows the exact workload in advance.

Abstract:Abstract: Based on the general laws of the floor damage caused by coal mining, the response relation between the floor rock damage and its electrical resistivity are mainly discussed. Then, the principle and method of the direct current electrical resistivity CT surveying technology are introduced. The survey plan is made according to movement characteristics of mining rock strata in floor, and the dynamic direct-current resistivity CT survey is then applied to predict the damage depth of coal floor. In the return airway of face 1028 in Huaibei Mine, two boreholes were drilled in the coal floor, with a certain number of electrodes buried in the holes, the survey profile was formed between them. With characteristics of electric fields in rock strata in different time measured according to advance of working face, and its electrical resistivity values simulated inversely, the responses of rock strata to electrical resistance during the evolution of fractures were obtained and the damage depth of coal floor in face 1028 was determined to be 17m, which provides visual and effective technical parameters for the coal mining safety. Test results show that direct current electrical resistivity CT technique can detect coal floor mining damage evolution process effectively, and illustrate the floor deformation and damage in the process of mining, which is conducive to the water-inrush forecast, prevention and control.

Abstract:Genetic algorithm (GA) is used for the optimal design of shell-and-tube heat exchangers due to the fact that traditional designs for shell-and-tube heat exchangers are complicated and uneconomical. To optimize the design of heat exchangers, mathematical models are established and the total costs are used as the objective function. Taking advantage of GA’s intelligent and multi-searching characteristics, researchers continuously iterate optimization variables and then obtain the minimum objective function of the design results within the optimal variable values and constraints. Two practical heat exchangers are used to test the research results. The Optimization results show that the optimized total costs have decreased by 18.2% and 7.98% respectively, which can also satisfy the heat transfer performance. Moreover, the results show that the design based on GA for shell-and-tube heat exchangers can significantly improve the economic efficiency of heat exchangers and thus can be applied to engineering practice.

Abstract:Considering the damage effect of porous media under triaxial compression, the calculation formula of effective stress is modified. It is verified that the formula can very well describe complete stress-strain process of gas-filled coal under triaxial compression. The permeability experiments under triaxial compression show that the relationship between the effective volumetric stress and permeability of gas-filled coal samples is negative exponent before the peak stress. It is still exponentially after the peak point, but the coefficient changes. The permeability of the gas-filled coal samples changes in reverse direction with the effective volumetric stress, that is, the effective volumetric stress increases when the permeability decreases, and vice versa.

Abstract:In order to consider the feasibility of practical implementation and reduce the complexity of OFDM systems, an improved SLM algorithm is proposed. The original data are segmented and scrambled, which breaks the correlation of the original data sequences, and reduces all sub-carrier phase coherence, thereby reducing the OFDM system PAPR. Following the linear nature of the Fourier transform, the obtained IFFT data sequences are linearly combined to get the new scrambling code sequences, such that strictly controlling the IFFT number, while getting more data sequences, which further reduces the system PAPR, and significantly reduces the computational complexity of the system. Theoretical analysis and simulation results show that the improved SLM algorithm can effectively suppress PAPR, while reducing the algorithm complexity and system complexity.

Abstract:This paper presents a dynamic hybrid substructure synthetic method for tower crane dynamic analysis. This method employs the transfer matrix method and the flexibility degree method respectively to formulate the vibration mathematical models of the tower body and tower top system substructures in the hoisting luffing plane. Based on the motion of the substructures in the interface and the dynamic harmonize condition, the frequency equations are established. Then the program is designed according to the mathematical models and firstly applied to the dynamic analysis of the QTZ63 tower crane in the construction site and the parameter identification of attached device and tower body. The test results show that the value calculated by the above method is quite approximate to the instrument measured value, which can meet the engineering requirements. Further study has found that , for the flexible long-distance attached tower crane, the method that introduces dynamic load coefficient for statics analysis of tower cranes is unprecise enough since there exist errors.This paper suggests to conduct site test and identification of the rigidity coefficient of attached device of the tower crane for the accident prevention of tower crane collapse by timely take measures.

Abstract:To explore the vibrating frequencies and rational impact factors of multi-span skew bridge, the recursive algorithm of vibrating frequency and finite element formulations of static and dynamic analysis are established for uniform section multi-span continuous skew bridge. The first five order frequency changes of equal-span multi-span continuous skew bridge and unequal-span multi-span skew bridge are compared. The interaction of vehicle-bridge system for two-span skew bridge is analyzed. The history curves for deflection and moment of middle-span are presented. The influence of obliquity on dynamic deflection and dynamic moment as well as the influence of vehicle velocity and obliquity on impact factors of deflection and moment are investigated. Results show that the fundamental frequency of multi-span skew bridge is identical to that of single span skew bridge. The higher order frequencies of single span skew bridge are distributed in frequencies of multi-span skew bridge, which mix other vibrating frequencies. The more the span number is, the more the other vibrating frequencies mingle. Obliquity has an important influence on dynamical characteristics of skew bridge. Impact effects of vehicle have no harmonious changing rule with vehicle velocity and obliquity. The impact factors of deflection and moment are different for skew bridge.

Abstract:Three specimens of sandwich joints with eccentricity being larger than a quarter of the column width in middle floor of frame are designed and loaded under cyclic loading. Their shear capacity, failure modes, and ductility, as well as energy dissipation are analyzed. The results show that the performance of sandwich joints with big eccentricity is good under cyclic loading. X-type reinforcements can be used to substitute for stirrups in the joint to bear shear forces. But the anchorage of longitudinal bars of beams in eccentric sandwich joints is relatively weak. Comparing to sandwich joints without eccentricity, the column longitudinal bars near the sandwich joints with big eccentricity are vulnerable to sudden change of strain.

Abstract:The security issues in mobile Ad hoc network, especially caused by inner malicious nodes are analyzed. By tracking the behavior of nodes, trust level of each node can be evaluated and managed; then actions of malicious nodes will be constrained and the security and reliability of entire network are enhanced. According to the features of Ad hoc. The scheme proposed in not only extends the conception of trust but also include the trust computation model and trust management mechanism. Simulation experiments show the novel scheme is more efficient than other trust schemes in traditional protocols.