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Photoacoustic Doppler flow measurement based on continuous wave laser excitation owns the merit of clearly presenting the Doppler power spectra. Extending this technique to dual wavelengths can gain the spectral information of the flow sample extra to the flow speed information. An experimental system with two laser diodes respectively operated at 405 nm and 660 nm wavelengths is built and the flow measurement with black and red dyed polystyrene beads is performed. The measured Doppler power spectra can vividly reflect the flow speed, the flow direction, as well as the bead color. Since it is straightforward to further apply the same principle to multiple wavelengths, we can expect this type of spectroscopic photoacoustic Doppler flow measurement will be developed in the near future which will be very useful for studying the metabolism of the slowly moving red blood cell inside microvessels.

The pipeline is the main channel for concrete pumping in construction, and lightweight, safe, long service life pipeline is very important for concrete pump trucks. This paper presents the design and experimental study on hybrid structure of carbon fiber reinforced polymer (CFRP) filament-winded strengthened circular long steel pipe. The filament-winded CFRP contains three layers: the inner layer for stress sharing of brittle steel tube, the middle layer for connecting to ductile steel flanges and the outer layer for explosion-proof and protection. With calculation of the hybrid structure stress, the design guideline of inner and outer layer CFRP is presented. Based on the design and test of the connection structure between pipe flange and CFRP, this paper conducted an optimization on the filament winding patterns of the middle layer. The experiment result shows the new hybrid structure pipeline can bear the pressure of 17 MPa and the axial loading of 210 kN, and the working requirements of concrete pumping can be satisfied. The test result indicates that the hybrid structure pipeline reduces 43% mass compared with the traditional double-layer steel pipe, and also the service life is 50% increased so as to the explosion-proof safety performance of concrete pump trucks is obviously improved.

In order to improve the reliability and service life of vehicle and diesel engine, the fatigue life prediction of the piston in a heavy diesel engine was studied by finite element analysis of piston, experiment data of aluminum alloy, fatigue life model based on energy dissipation criteria, and machine learning algorithm. First, the finite element method was used to calculate and analyze the temperature field, thermal stress field, and thermal–mechanical coupling stress field of the piston, and determine the area of heavy thermal and mechanical load that will affect the fatigue life of the piston. Second, based on the results of finite element calculation, the creep–fatigue experiment of 2A80 aluminum alloy was carried out, and the cyclic response characteristics of the material under different loading conditions were obtained. Third, the fatigue life prediction models based on energy dissipation criterion and twin support vector regression are proposed. Then, the accuracy of the two models was verified using experiment data. The results show that the model based on the twin support vector regression is more accurate for predicting the material properties of aluminum alloy. Based on the established life prediction model, the fatigue life of pistons under actual service conditions is predicted. The calculation results show that the minimum fatigue life of the piston under plain condition is 2113.60 h, and the fatigue life under 5000 m altitude condition is 1425.70 h.

Previous photoacoustic flow measurements have been demonstrated with various modalities including Doppler frequency shift measurement from intensity modulated continuous laser wave and pulsed photoacoustic Doppler cross- correlation from nanosecond laser pulse. Here, we propose and demonstrate a new type of photoacoustic Doppler velocimetry based on a hybrid approach: we applied a supercontinnum laser source with picosecond pulse and 40 MHz repetition rate, and then use electo-optic modulator to modulate the intensity at 1 MHz. This method can potentially improve the signal to noise ratio due to pulse excitation of photoacoustic signal, and at the same time to achieve the high resolution of Doppler frequency shift due to the intensity modulation. With this method, we measured the moving speeds of various samples at the range of 0.1-1.6mm/s and obtained accurate results. The extra advantage of using supercontinnum laser pulses is that the spectral range can be chosen by using spectral filter thus to realize the multispectral measurement. To demonstrate this, we set the spectral filter working at five ranges at 500nm, 550nm, 600nm, 650nm, 700nm center wavelengths all with 100nm spectral width and measured different materials as moving targets fixed on the translation stage, including such as graphene thin layer, black tape, red and black dyed microspheres.

With the rapid development of communication and transportation technologies, the urban area is increasingly becoming an ever more dynamic, comprehensive, and complex system. Meanwhile, functional polycentricity as a distinctive feature has been characterizing urban areas around the world. However, the spatial structure of the urban area has yet to be fully comprehended from a dynamic perspective, and understanding the spatial organization of polycentric urban regions (PUR) is crucial for issues related to urban planning, traffic control, and urban risk management. The analysis of polycentricity strongly depends on the spatial scale. In order to identify functional polycentricity at the intra-unban scale, this paper presents a traffic flow-embedded and topic modeling-based methodology framework. This framework was evaluated on real-world datasets from the Wujiang district, Suzhou, China, which contains 151,419 records of taxi trajectory data and 86,036 records of points of interest (POI) data. This paper provides a novel approach to examining urban functional polycentricity via combining urban function distribution and spatial interactions. This proposed methodology can help urban authorities better understand urban dynamics in terms of function distribution and internal connectedness and facilitate urban development in terms of urban planning and traffic control.

With the aim of enhancing both reliability and fatigue life of gasket, this study combines finite element analysis, orthogonal experimental design, dynamically-guided multi-objective optimization, and the non-dominated sorting genetic algorithm with elitist strategy to optimize the geometric parameters of the cylinder gasket. The finite element method was used to analyze the temperature field, thermal-mechanical coupling stress field, and deformation of cylinder gasket. The calculation results were experimentally validated by measured temperature data, and comparison results show that the maximum error between calculated value and experiment value is 7.1%, which is acceptable in engineering problems. Based on above results and orthogonal experiment design method, the effects of five factors, including diameter of combustion chamber circle, diameter of coolant flow hole, length of the insulation zone between third and fourth cylinders, thickness of gasket, and bolt preload, on three indexes: temperature, stress, and deformation of gasket, were examined in depth. Through the variance analysis of the results, three important factors were identified to proceed later calculation. The dynamically guided multi-objective optimization strategy and the non-dominated sorting genetic algorithm were effectively used and combined to determine the optimal geometric parameters of cylinder gasket. Furthermore, calculation results suggest that temperature, stress, and deformation of the optimized cylinder gasket have been improved by 27.88 K, 16.84 MPa, and 0.0542 mm, respectively when compared with the origin object, which shows the excellent performance of gasket optimization and effectiveness of the proposed optimization strategy.

The emphasis of this paper lies in the development of an efficient approach to reproduce the behaviors of the scramjet-powered hypersonic system with high fidelity. The modeling of the dual-mode scramjet powered hypersonic vehicle dynamics with shock interaction, Ram-to-Scram transition, and finite rate chemistry reaction is firstly introduced. The structure of surrogate model is identified with the implement of iterative fractional factorial design (IFFD). In order to declare the reliability of the surrogate models, ν-gap metric is applied to distinguish the difference among these surrogate models in terms of closed-loop performance. The results show that the influence of Mach number on the aerodynamics should not be overlooked, and the effect of propulsion system to the aerodynamic pitch moment is dramatic. Further, the partial Kriging model appears to have the closest plants throughout the flight envelope compared with the full Kriging model and polynomials model. Nevertheless, considering the briefness of analytical expression, the polynomials model may be an alternative approach for design-oriented modeling.

Background: Percutaneous endoscopic interlaminar discectomy (PEID), which poses advantages for certain types of herniated disc, is gaining wider acceptance in clinical practice. We retrospectively analyzed the efficacy of the PEID technique in treatment of calcified lumbar disc herniation. Study Design: A retrospective case-control study. Setting: University hospital in China. Objective: To evaluate the efficacy of the PEID technique in treatment of calcified lumbar disc herniation, and a comparison between calcified and noncalcified disc herniation was drawn to analyze the causes of herniated disc calcification. Methods: Data from patients who underwent full-endoscopic lumbar discectomy in our department between March 2011 and May 2013 were collected. Thirty cases with calcified lumbar disc herniation were included in the study group, and 30 age-, gender-, and body mass index (BMI)-matched cases with noncalcified lumbar disc herniation served as controls. Perioperative data, preoperative and postoperative Visual Analog Scale (VAS) scores, Oswestry Disability Index (ODI) values, MacNab scores, and postoperative low-extremity dysesthesia among patients in the 2 groups were collected. Results: The values of computed tomography (CT) in the calcified group were significantly higher than those in the noncalcified group (P < 0.01). The preoperative disease courses in the 2 groups were similar. However, there was a statistically significant difference in the duration of traditional Chinese medicines (TCM) administration (P < 0.01). VAS and ODI scores improved significantly after surgery, but there were no significant differences between the 2 groups (P > 0.05). Three months after surgery, the rate of low-extremity dysesthesia in the calcified group was significantly higher than that in the control group (P = 0.03) but became similar at 6 months. By applying MacNab criteria the proportions of good and excellent were greater than 90% in both groups, and there was no difference between groups (P > 0.05). Limitations: The sample size was small in this retrospective study. Conclusion: The PEID technique is an effective method in the treatment of calcified lumber disc herniation, although the rate of postoperative dysesthesia is higher in this group during the early postoperative period. Long-term TCM administration may be related to the calcification of herniated lumbar discs. Key words: Lumbar disc herniation, percutaneous endoscopic lumbar discectomy, interlaminar approach, calcification

In the light of the broad range of hypersonic flight conditions, a design method of switching control based on guardian maps is proposed to guarantee the global stability within the flight envelope. First, a linear parameter varying (LPV) model of a hypersonic vehicle is established over a range of hypersonic flight conditions. The parameters of controller are determined by pole placement technology with the target pole locations at the boundaries of the parameters variation range. Second, a new range of flight conditions that ensures system stability with current controller is analyzed based on guardian maps. The execution of the iterative process is used to determinate the set of controller parameters overall the flight envelope with initial target pole locations. By switching controller parameters the closed-loop performance is guaranteed over the entire flight envelope. The simulation shows that the proposed design method has the ability to ensure the global stability over the flight envelope, and achieving good tracking performance.

Compared with traditional vehicles, the dynamic model of hypersonic vehicles features higher nonlinearity, tighter coupling and stronger uncertainty. What's more, the designed controller needs to have more stringent performance demands as well as robustness requirements. According to the guardian maps theory, a proposed design method can adaptively adjust control parameters in relation to the given control structure for hypersonic vehicles. First, a linear parameter varying (LPV) model of a hypersonic vehicle is established, and after that handling qualities are translated in terms of eigenvalue confinement. Then for a fixed controller architecture and initial controller gains, a set of control parameters is adjusted automatically using this theory while ensuring generalized stability in the expected flight process. Finally, an example of a hypersonic vehicle is provided in simulation to verify the feasibility of the proposed control method.

The objective of this study was to compare the efficacy and safety of piperacillin-sulbactam (PIP-SBT) and piperacillin-tazobactam (PIP-TAZ) in the treatment of bacterial respiratory and urinary tract infections. A randomised, single-blind, controlled clinical trial was performed. Differences in clinical efficacy, bacteriology and safety between the two groups were subjected to statistical analysis, including intent-to-treat (ITT) analysis. A total of 215 cases were enrolled, with 203 complete cases (99 PIP-SBT, 104 PIP-TAZ). A total of 209 cases (103 PIP-SBT, 106 PIP-TAZ) were included in the ITT analysis and a total of 212 cases (104 PIP-SBT, 108 PIP-TAZ) were included in the safety analysis. Overall efficacy rates of PIP-SBT and PIP-TAZ were 93.2% and 93.4%, respectively. Overall bacterial eradication rates of the two groups were 95% and 97.59%, respectively. Among the PIP-SBT group, eight patients (7.69%) had adverse events, including four probable drug-related events. Among the PIP-TAZ group, nine patients (8.33%) had adverse events, including one definitely drug-related and four probable drug-related events. All differences between the two groups were insignificant. PIP-SBT could be a suitable replacement for PIP-TAZ in the therapy of community-acquired respiratory and urinary tract infections caused by beta-lactamase-producing bacterial isolates.

The turbine system of a two-stage turbocharger composed of high pressure turbine (HT), low pressure turbine (LT), and by-pass valve decides distribution and utilization of exhaust gas energy and influence performance of two-stage turbocharger in whole operational conditions. Besides, characteristics of turbine is expressed by envelop line of characteristic lines in different speeds. So turbine can be conveniently selected compared with compressor with similarity theory. Therefore, two-stage turbocharger matching begins from turbine system matching in the paper. In two-stage turbocharger, cooler efficiency, cooler loss, and by-pass valve open besides turbochargers will influence turbocharging system performance and design of cooler and by-pass valve are important contents of turbocharging system matching. The paper matched intercooler, by-pass valve open, compressors, and turbines jointly. Calculation model for turbocharger matching was built, and turbine performance is get from reference turbine based on similarity theory; influence of compressor ratio distribution, cooler efficiency, and pressure drop in cooler imposing on compressor work was analyzed; and influence of turbine flow capacity and by-pass valve imposing on output working in expanding process was studied; the method for matching of two-stage turbocharging system in whole operational condition is studied. Matching analysis was made aiming at two-stage turbocharging system of a type of high power density diesel engine, and design for turbocharging system was finished. Matching result using the method is compared to matching result using traditional method. Analysis result proves that using the method matching points in different operational conditions are located in more reasonable zone of compressor MAP.

Sir, We read the article by Qu et al1 with great interest. The authors investigated the role of procalcitonin (PCT) in distinguishing bacterial infections in febrile patients. We believe that this topic can be enriched with the points listed below: Groups 1 and 2 represented bacterial infection groups which consisted of 161 hospital acquired infection cases (58%) and 115 community acquired infection cases (42%). If there are significant differences in the levels of PCT, C-reactive protein (CRP), interleukin-6 (IL-6) and serum amyloid A (SAA) between hospital acquired infection and community acquired infection cases, it can be useful in guiding antibiotic treatment. Bacterial pneumonia was the most common diagnosis in their study, but Streptococcus pneumoniae which is the most common aetiological agent of pneumonia, was not isolated in any of their febrile patients. This point should be clarified. The PCT level of some patients in the bacterial infection group was below the cut-off level. It is important to know which infections and bacteria cause low PCT levels. Mortality among patients was not mentioned. It would be important to know whether there was a significant difference in PCT levels between survivors and non-survivors. Finally, we think that the aforementioned data will be helpful to increase the significance of PCT especially in emergency department and intensive care unit.

The study of digital Chinese calligraphy has become more valuable nowadays. While existing researches on Chinese calligraphy analysis are primarily focused on stroke-based character recognition and simulation, we propose a global feature descriptor to deal with style recognition problem in this paper. The proposed method extracts three categories of character features: position features, proportion features and projection features. These features are then used to train an SVM classifier of calligraphy style. We test the global feature based classifier on five-style Chinese calligraphy character set. The experimental results show that the proposed method can achieve good classification accuracy, proving the effectiveness of the global feature descriptor in calligraphy style recognition.

Market information management has always been an essential component of good marketing management practice, but only possession of market information is not sufficient. Recently, processing market information has been of increasing interest to organization researchers, they suggested that improving the market information processing capabilities is important for marketing managers to understand and track changes in users’ needs, wants, preferences and consumption patterns. However, although the literature pertaining to the study of organizational information processing is growing, there lacks a specific analysis as to using online users’ information behavior to process market information, research is still needed to guide firms on how to integrate and manage market information based on consumer behavior. In an attempt to fill in the gap, this study reviews the relevant literatures and proposes that using users’ three-dimensional information behavior to capture the user’s interest in information and filter incoming information will be a very efficient way to process market information. We will use the Mobile Internet click stream data from some WAP website to characterize the users’ online information behavior. In addition, we will examine the relationships between the three dimensions of consumer online information behavior and the performance of the website. This study attempts to contribute to a better understanding of market information processing, our understanding of how organizations process market information can be advanced substantially on the basis of principles information processing.

For complicated Software-Intensive System, it is always hard to guarantee the reliability and safety of software. Effective methods for detecting faults and isolating software fault from hardware fault are desiderated especially. In order to detect and isolate fault in SIS, a method called runtime software monitoring is studied, and a new kind of runtime software monitoring system(RSMS) is constructed in this paper. The RSMS can not only detect software fault by observing software behavior to determine whether it complies with its intended behavior, but also can assist to isolate software fault from hardware fault and to locate software fault based on fault symptoms acquired by our method. The software architecture of RSMS is presented from different views by using “4+1” view model and layer architectural style. The RSMS prototype is implemented through architecture-based software development method. By applying the prototype in practice, it proved that the RSMS prototype is feasible and effective for detecting and diagnosing faults in SIS.

Reputation systems are designed for reducing the risk entailed in interactions among total strangers in electronic marketplaces. Such systems can be used to collect and aggregate feedback on the past behavior of participants in electronic transactions, so as to derive reputation scores assumed to predict likely future behavior.The security of reputation system is vital for the system to run correctly, if reputation system is not secure, it may not be able to produce a correct result, and consequently affects the process of decision making. In this paper, a secure reputation system based on secure multiparty computation is proposed. Each of feedback provider generates an anonymous identity using smart card, and provides a rating about feedback target by a secure multiparty computation to a querying user. The system contains the following desirable features: privacy-preserving of feedback provider, tamper-preventing of feedback, masquerade-proofing of identity, shilling attack-preventing.

ERA is the acronym of environment, reactive rules and agent; the model is a new effective multi-agent cooperation framework, which has been successfully applied in a wide range of areas. Multi-port Container Stowage (MPCS) is a more practical problem. However, multi-port makes the container stowage problem more difficult. This paper presents a MPCS model based on time series and a multi-agent ERA model based on belief to solve the multi-port container stowage problem. The algorithm introduces the belief concept into agents and creates a multi-agent ERA model. The searching direction and strength of the agents are determined by the learning machine using belief parameter. Agent has the ability to evaluate its searching path. At last, the feasibility and efficiency of the model are validated by the experimental result.

Multi-Agent model based on belief interaction is used to solve the function optimization problems in this paper. “Belief” is led into the Agent, being the parameter of learning machine to decide the searching direction and intensity of the Agent in the environment. It is also the interaction information between Agents. Agent has the ability to evaluate its path in the past. In this way, Agent can find optimization object rapidly and avoid partial extremum at the same time. Finally, several benchmark problems are considered to evaluate the performance of this model. The experimental results prove the efficiency of this model when solving optimization problems.