Search

The application of distributed temperature sensors(DTS) to monitor producing zones ofhorizontal well through a real-time measurement of a temperature profile is becoming increasinglypopular. The information from DTS can potentially be transformed to obtain the permeability alongto the wellbore and well completion method and so on. The relationship between these parametersand the real-time temperature distribution along the wellbore is very important. Based onmass-,momentum-,and energy-balance equations, this paper established a model to predict thetemperature along the horizontal wellbore. The models presented in this paper account for heatconvective, fluid expansion, heat conduction, and viscous dissipative heating. Wellbore temperaturecurves are plotted by computer iterative calculation. In addition, this paper revealed the relationshipbetween wellbore temperature distribution and different characteristics, such as permeability alongto the wellbore and well completion method. The analysis results show that permeability differenceand different well completion methods may lead to different downhole temperature distribution atthe same time step, different production rate, different wellbore temperature as well as the change offriction factor in the wellbore. From the temperature distribution and temperature derivative curvesin different cases, we could easily derive the permeability distribution along wellbore and thelocation of the perforated intervals and the fractures.

This paper presents the current most common fatigue-driving detection methods. The advantages and disadvantages of these detection methods are compared with. Moreover, several major products of the current fatigue detection are listed briefly. Furthermore, the development trends of driving-fatigue detection technology are prospected. The author believes that driver fatigue testing standards need to be further clarified and the non-contact detection method of driving-fatigue needs to be developed deeply. Information fusion is an important orientation for driving fatigue and we should design the cost-efficient detection products for fatigue-driving.

The main research methods to predict and research wind loads on buildings at home and abroad include wind tunnel tests, field measurement and numerical simulation. However, the wind tunnel tests and field measurement require big funds, long cycle and complicated measurement. Moreover, numerical simulation technology is quite mature. In this paper, based on fluid dynamics software CFD and criteria Reynolds k-ε turbulence model, wind field of the village flat roof with parapet is studied using the numerical simulation technology. Furthermore, the wind pressure data in different wind angles are processed and analyzed. The results show that wind angle has a significant impact on the wind pressure and its distribution. When the wind angle is 0 °, the air pressure-fluctuation in each node of the roof is small, and the pressure coefficient is steady between -1.50 and -2.00. When the wind angle is 45 °, the air pressure fluctuation in each node of the roof is large, and the pressure coefficient fluctuates between -0.8 and -3.0. When the wind angle is 90 °, the wind pressure-fluctuation in each node of the roof is equal to the fluctuation between 0 ° and 45 °wind direction angle, and the wind pressure coefficient fluctuates between -0.7 and -1.7. When incoming flow is along the asymmetric axis, the wind pressure-fluctuation is large, and the wind pressure is greater than that in the large negative pressure zone which is along the symmetry axis, which can bring serious damage on the roof.

Reverse Nearest Neighbour (RNN) queries play an important role in applications such as internet of vehicles, decision support systems, profile based marketing and so on. Recently, more attention has been paid to the problem of efficient distributed RNN computation in mobile cloud computing environment. A major downside of the existing RNN is its inherent sequential nature and using in-memory algorithm, which limits its applicability to massive data. In this paper, we propose a novel distributed caching based method to efficiently improve the performance of the RNN calculation in a distributed environment. Extensive experiments using both real and synthetic datasets demonstrated that our proposed methods are the state-of-the-art algorithms in scalable RNN queries.

Braking deceleration of passenger-car has great influence on the pedestrian motion process after collision of human-vehicle accident, but it is considered not enough in current accident reconstruction and vehicle-speed analysis. In order to improve the accuracy of accident reconstruction, a computer simulation model of pedestrian-vehicle accidents based on finite element (FE) method and human parameters of Chinese adult human body is established. In this article, based on the FE model, human-vehicle crash is simulated through involving the influence of braking deceleration of passenger-car. For the application of the vehicle-speed analysis, the motion performance of pedestrian after collision were studied and the correlation between the pedestrian throw distance and vehicle impact speed are investigated. The influence of braking deceleration in same impact speed is analyzed. Research results show that the vehicle brake deceleration has a certain influence on the throw distance of pedestrian and it should be taken into account on the accident reconstruction. We can conclude that pedestrian throw distance can be used to estimate the vehicle collision speed accurately when drivers take full braking measure during the crash.

Water is a vital natural resource, which is becoming increasingly scarce around the world. The balance between water availability and demand has reached critical levels in many regions due to water demand increasing, and availability diminishing through drought and over-extraction. Water resources have been very important to us human beings since our ancient society. And the use of water in irrigation is a momentous part. Effective and productive irrigation requires the most appropriate water application strategies that take soil, climate, and farming operations into account. In addition to this, inputs used must be applied to where it is required without giving any harmful effects to the environment. In this study, we took a comprehensive consideration of the related records, summarized the methods of water-saving technology in the world for need.

According to the experience of traffic accident investigation over the years, the pointer of some crashed vehicles’ speedometer will stay in one place because of collision spread or heavily vibration, which may indicate the vehicle collision speed. However, the correlation between the residual speed value and actual vehicle collision speed still remains to be examined. For the practical needs of traffic accident reconstruction, this research work is carried out. Based on the principles of traditional speedometers, vehicle impact mechanics and failure mechanism, the damage and failure mode of speedometer in collision are studied. Through the statistics of 15 real traffic accident cases, the features and law about the pointer information of damaged speedometers are obtained initially. As an example, one of these cases is analyzed and calculated to verify the assumption. The availability of the mark information on the indicated place of speedometer after accidents (i.e. the correlation between the speed value of pointers and actual vehicle collision speed) is discussed, which can provide effective means and references for accident reconstruction and vehicle speed identification.

This paper discusses particle deposition in rectangle air-conditioning duct using RSM (Reynold Stress Model) and random trajectory particle model. Particle with nominal diameters of 10-200μm are simulated at each of three nominal air speed: 4m/s, 6m/s and 8m/s, respectively, in the cross-section sizes of 160×120, 500×250, 1000×320mm. In simulation, the paper compares and analyzes the influence factors of particles deposition in volume surface ratio of the given duct. The results show that: 1) particle deposition velocity increases with volume surface ratio; 2) As the inlet air speed increasing, when the particles deposited to floor and vertical wall, the image of dimensionless deposition velocity Vs dimensionless relaxation time shows a coincident trend when the duct cross-section sizes are 500×250, 1000×320mm, but has great differences with the image of 160×120mm.

To solve network security situation prediction problem, a novel Prediction approach for network security situation based on artificial Immune system and Phase Space Reconstruction (PIPSR) is proposed. In PIPSR, we use phase space reconstruction to analyze the time series of network security situation and to reconstruct proper time series phase space; then, we use immune evolution mechanism to construct corresponding prediction model for network security situation; and lastly we use this prediction model to forecast network security situation. The simulation results show that PIPSR can more exactly forecast the future network security situation than GAP and BPNNP.

To effectively prevent large-scale network security attacks, a novel Predication Approach for Network Security Situation inspired by Immunity (PANSSI) is proposed. In this predication approach, the concepts and formal definitions of antigen and antibody in the network security situation predication domain are given; meanwhile, the mathematical models of some antibody evolution operators being related to PANSSI are exhibited. By analyzing time series and computing the affinity between antigen and antibody in artificial immune system, network security situation predication model is established, and then the future situation of network security attacks is predicted by it. Experimental results prove that PANSSI can forecast the future network security situation real-timely and correctly, and provides a novel approach for network security situation predication.