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801.
Automobile black boxes are devices that collect information regarding vehicle operation and the driver’s operating situation
in the case of a traffic accident. The information collected from the automobile black box, which can also be used during
normal driving, can provide information about dangerous driving cognition. This study was designed to analyze characteristics
of dangerous driving data and build a dangerous driving cognition system as follows. First, dangerous driving is divided into
four types by considering the vehicle’s movement, such as acceleration, deceleration, turning and statistical data of traffic
accidents. Second, dangerous driving data were collected by vehicle tests using the automobile black box, and characteristics
of the driving data were analyzed to classify dangerous driving. Third, a standard threshold was chosen to recognize dangerous
driving, and an algorithm of dangerous driving cognition was created. Finally, verification was conducted by vehicle tests
with automobile black boxes embedded with the developed algorithm. The presented recognition methods of dangerous driving
can be used for on/off-line management of drivers and vehicles. Scientific traffic accident databases can be built with this
driving and accident information, and can be used in various industrial areas. 相似文献
802.
Fuel injection during negative valve overlap period was used to realize diesel homogeneous charge compression ignition (HCCI)
combustion. In order to control the combustion, CO2 in-cylinder injection was used to simulate external EGR. Effects of CO2 injection parameters (injection timing, quantity, pressure) on HCCI combustion and emission characteristics were investigated.
Experimental results revealed that CO2 in-cylinder injection can control the start of combustion and effectively reduce NOx emission. Either advancing CO2 injection timing or increasing CO2 injection quantity can reduce peak cylinder pressure and mean gas temperature, delay the starts of low temperature reaction
(LTR) and high temperature reaction (HTR), and lower pressure rise rate; NOx emission was reduced, while smoke, HC, and CO emissions increased. Since the combustion phase was improved, the indicated
thermal efficiency was also improved. Injection pressure determines the amount of disturbance introduced into the cylinder.
Generally, with the same injection quantity, higher injection pressure results in higher momentum flux and total momentum.
Larger momentum flux and momentum has a stronger disturbance to air-fuel mixture, resulting in a more homogeneous mixture;
therefore, larger injection pressure leads to lower NOx and smoke emissions. 相似文献
803.
H. J. Kim C. H. Bae S. H. Kim H. Y. Lee K. J. Park M. W. Suh 《International Journal of Automotive Technology》2009,10(1):123-129
Urban transit is a complex system that contains both electrical and mechanical entities; therefore, it is necessary to construct
a maintenance system for ensuring safety during high-speed driving. Expert systems are computer programs that use numerical
or non-numerical domain-specific knowledge to solve problems. This research aims to develop an expert system that diagnoses
the causes of failures quickly and displays measures to correct them. For the development of this expert system, the standardization
of a failure code classification and the creation of a Bill of Materials (BOM) were first performed. Through the analysis
of both failure history and maintenance manuals, a knowledge base has been constructed. Also, for retrieving the procedure
of failure diagnosis and repair linking with the knowledge base, we have built a Rule-Based Reasoning (RRB) engine with a
pattern matching technique and a Case-Based Reasoning (CBR) engine with a similar search method. Finally, this system has
been developed as web based in order to maximize accessibility. 相似文献
804.
Online license plate matching procedures using license-plate recognition machines and new weighted edit distance 总被引:1,自引:0,他引:1
Francisco Moraes Oliveira-NetoLee D. Han Myong K. Jeong 《Transportation Research Part C: Emerging Technologies》2012,21(1):306-320
License-plate recognition (LPR) technology has been widely applied in many different transportation applications such as enforcement, vehicle monitoring, and access control. Recently, there has been effort to exploit an LPR database for vehicle tracking using popular template matching procedures. Existing template matching procedures assume that the true reference string is always available. However, under a two-point LPR survey, a vehicle could have its plate misread at both locations generating a pair of misread strings (or templates) with no reference for matching. To compensate for LPR misreading problem, we propose a new weight function based on a probability model to match the observed outcomes of a dual LPR setup. Also, considering that reversal errors are never made in LPR machines, new editing constraints as a function of the string lengths are proposed to avoid compensation for reversal errors. These editing constraints are incorporated into the constraint edit distance formulation to improve the performance of the matching procedure. Finally, considering that previous template matching procedures do not take advantage of passage time information available in LPR databases, we present an online tracking procedure that considers the properties of probability distribution of vehicle journey times in order to increase the probability of correct matches. Experimental results show that our proposed procedure can improve the accuracy of LPR systems and achieve up to 97% of positive matches with no false matches. Further research is needed to extend the ideas proposed herein to plate-matching with multiple, i.e., more than two, LPR units. 相似文献
805.
Min-Wook Kang Manoj K. Jha Paul Schonfeld 《Transportation Research Part C: Emerging Technologies》2012,21(1):257-286
This paper presents an intelligent optimization tool that assists planners and designers in finding preferable highway alignments, connecting specified endpoints or zones. It integrates genetic algorithms with a geographic information system (GIS) for optimizing highway alignments and processes massive amounts of relevant data associated with highway design and alternative evaluation. To show the applicability of the proposed model to a real-world problem, two actual highway projects in the state of Maryland have been analyzed using the model. An extensive analysis of sensitivity to key model parameters is also conducted to describe the model capabilities. The analysis results show that the model can effectively optimize highway alignments in an area combining complex terrain and various types of natural and cultural land-use patterns, and provide detailed information of optimized alignments as a model output. It is also found that the alignments optimized by the model are quite similar to those obtained through conventional manual methods by a state agency, but the model can greatly reduce the time required for highway planning and design as well as produce lower cost solutions. Finally, the results confirm that all dominating and alignment-sensitive costs should be simultaneously evaluated in the alignment optimization process because many trade-off opportunities exist among those costs. The proposed model can greatly contribute to the productivity of highway planners as well as to the quality of the resulting infrastructure. 相似文献
806.
Social inclusivity through public transportation: a strategic approach to improve quality of life in developing countries 下载免费PDF全文
Welfare services such as healthcare and education are commonly recognised as determinants of physical quality of life indices during the early phases of development in the third world. In order to benefit from these services, it is important that the general public have the mobility means to access welfare provision centres. However, very low vehicle ownership under the conditions of low per‐capita incomes and large shares of population living in deep rural areas prevent the masses from accessing such services, thereby retarding the process of social development, which is reflected in the very poor physical quality of life indices in low‐income countries. Public transportation could offer a viable and affordable solution to this apparent ambivalence. It could permit mobility for poor masses in spite of low per‐capita vehicle ownership enabled by the national income levels. The present research demonstrates this strategic niche through an econometric examination of the evolution of the physical quality of life indices such as maternal mortality, infant mortality and literacy as against the healthcare, education and affordable mobility proxies in post‐independent Sri Lanka. The country, which was then referred to as Ceylon, is often cited as a rare example of achieving social inclusion and reduced marginalisation and thereby a high social welfare standing, in spite of relatively poor per‐capita income levels. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
807.
绕Wigley船自由表面粘性流场计算 总被引:7,自引:1,他引:6
本文采用商用粘性流场求解软件COMET计算带自由液面绕Wigley船的粘性流动,网格数约为216000。计算中使用标准k-ε湍流模式和壁函数。用HRIC算法确定自由面。同时域步进法得到稳态解,计算的在傅氏数为0.30时的阻力结果与模型试验测量值吻合良好。预报的船体周围的波型及船体表面的波面形状也较合理。 相似文献
808.
Co-operation and competition in international container transport: strategies for ports 总被引:1,自引:0,他引:1
This paper focuses on the response of port authorities to the changing market environment in which they operate. It documents the changes taking place in the relationships between port authorities and terminal management companies and considers the strategic issues faced by these groups and other port interests. In particular, it investigates the potential conflicts of interest for a port authority in matters related to the level of competition amongst terminals within a port and the amount of competition amongst ports. 相似文献
809.
T. Fang R. E. Coverdill C. -F. F. Lee R. A. White 《International Journal of Automotive Technology》2008,9(5):551-561
An optically accessible single-cylinder high speed direct-injection (HSDI) Diesel engine equipped with a Bosch common rail
injection system was used to study low temperature Modulated Kinetics (MK) combustion with a retarded single main injection.
High-speed liquid fuel Mie-scattering was employed to investigate the liquid distribution and evolution. By carefully setting
up the optics, three-dimensional images of fuel spray were obtained from both the bottom of the piston and the side window.
The NOx emissions were measured in the exhaust pipe. The influence of injection pressure and injection timing on liquid fuel
evolution and combustion characteristics was studied under similar fuel quantities. Interesting spray development was seen
from the side window images. Liquid impingement was found for all of the cases due to the small diameter of the piston bowl.
The liquid fuel tip hits the bowl wall obliquely and spreads as a wall jet in the radial direction of the spray. Due to the
bowl geometry, the fuel film moves back into the central part of the bowl, which enhances the air-fuel mixing process and
prepares a more homogeneous air-fuel mixture. Stronger impingement was seen for high injection pressures. Injection timing
had little effect on fuel impingement. No liquid fuel was seen before ignition, indicating premixed combustion for all the
cases. High-speed combustion video was taken using the same frame rate. Ignition was seen to occur on or near the bowl wall
in the vicinity of the spray tip, with the ignition delay being noticeably longer for lower injection pressure and later injection
timing. The majority of the flame was confined to the bowl region throughout the combustion event. A more homogeneous and
weaker flame was observed for higher injection pressures and later injection timing. The combustion structure also proves
the mixing enhancement effect of the liquid fuel impingement. The results show that ultra-low sooting combustion is feasible
in an HSDI diesel engine with a higher injection pressure, a higher EGR rate, or later injection timing, with little penalty
on power output. It was also found that injection timing has more influence on HCCI-like combustion using a single main injection
than the other two factors studied. Compared with the base cases, simultaneous reductions of soot and NOx were obtained by
increasing EGR rate and retarding injection timing. By increasing injection pressure, NOx emissions were increased due to
leaner and faster combustion with better air-fuel mixing. However, smoke emissions were significantly reduced with increased
injection pressure. 相似文献
810.