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991.
In this paper, we propose a precise and reliable positioning method for solving common problems, such as a navigation satellite’s signal occlusion in an urban canyon and the positioning error due to a limited number of visible navigation satellites. This is an integrated system of the navigation satellites system and a vision system. In general, the navigation satellite positioning system has a fatal weakness in that it can not calculate a position coordinate when its signal is occluded by some obstacle. For this reason, positioning by using the navigation satellites system can not be used for a variety of applications. Therefore, we propose as a method to integrate both the navigation satellites system and the vision system. Some target objects that have accurate position coordinates, for example, in an outdoor shaded area like an urban canyon, are installed into the vision system. When the vision system recognizes a target object it loads the accurate coordinate of that target object. Then, it measures the distance by using the disparity from the camera sensor to the target object. These distance and object coordinate data are used for positioning with the navigation satellites system’s data. This integrated system can be used for the positioning solution where the user is in unfavorable conditions. This paper shows that the algorithm of integrated system and the numerical test performed. The results indicate that the reliable and stable positioning can be obtained by introducing the vision system to the satellite navigation system. 相似文献
992.
N. Kim H. Lohse-Busch A. Rousseau 《International Journal of Automotive Technology》2014,15(2):263-271
Owing to ever more stringent regulations and customers’ expectations, auto manufacturers have been considering numerous technology options to improve vehicle fuel economy. One of these is transmission technology, which has been shown to be one of the most cost-effective technologies. Over the past few years, transmissions have significantly evolved and have impacted both performance and fuel efficiency. As one of the advanced tranmissions, the dual clutch transmission (DCT) is the first automatic transmission to provide better efficiency than manual transmissions. DCTs provide reduced shift shocks and better driver comfort in addition to higher top speeds and torques. In this paper, a model and shifting controller for the DCT are developed in the vehicle systems context using Autonomie, a model-based vehicle simulation tool. Finally, the Autonomie DCT model and control strategy are validated using vehicle test data from Argonne’s Advanced Powertrain Research Facility. 相似文献
993.
K. -B. Kim K. -W. Choi K. -H. Lee 《International Journal of Automotive Technology》2012,13(3):401-407
A relatively new approach for improving fuel economy and automotive engine performance involves the use of automotive combined
cycle generation technologies. The combined cycle generation, a process widely used in existing power plants, has become a
viable option for automotive applications due to advances in materials science, nanotechnology, and MEMS (Mico-Electro Mechanical
Systems) devices. The waste heat generated from automotive engine exhaust and coolant is a feasible heat source for a combined
cycle generation system, which is basically a Rankine cycle in the context of this study. However, there are still numerous
technical issues that need to be solved before the technology can be implemented in automobiles. A simulation was performed
to examine the amount of waste energy that could be recovered through the use of a combined cycle system. A simulation model
of the Rankine cycle was developed using Cycle-Tempo software. The simulation model was ultimately used to evaluate the rate
of waste heat recovery and the consequential increase in the overall thermal efficiency of the engine with the combined cycle
generation system under typical engine operating conditions. The most effective automotive combined cycle system recovered
68% of the waste heat from the exhaust and coolant, resulting in a 6% improvement in engine efficiency. The results are expected
to be beneficial for evaluating the feasibility of combined cycle generation systems in automotive applications. 相似文献
994.
This paper develops a computational model that can analyze the kinematics and compliance characteristics of the front suspension
of a commercial vehicle. This computational model is called the flexible multi-body dynamic model because it is developed
by interfacing the finite element model of the multi-leaf spring with the dynamic model of the front suspension. In this paper,
the bump mode and roll mode tests are performed with a suspension parameter measuring device (SPMD). An excitation load for
creating the bump mode and roll mode motion is applied on the left and right tires slowly in in-phase and out-of-phase modes.
In the test, wheel rate, toe angle change, caster angle change, and camber angle change, which together represent the wheel
alignment, are measured along with the longitudinal and lateral wheel center loci which together represent the wheel center
trajectory change. The reliability of the developed computational model is verified by comparing the simulation results with
the SPMD test results. The developed flexible multi-body computational model will provide useful information on kinematics
and compliance characteristics in the earliest stages of the commercial vehicle design process. 相似文献
995.
J. -H. Choi S. -H. Choi D. Park C. -H. Park B. -O. Rhee D. -H. Choi 《International Journal of Automotive Technology》2012,13(2):273-277
The quality of an injection molded part is largely affected by the mold cooling. Consequently, this makes it necessary to
optimize the mold cooling circuit when designing the part but prior to designing the mold. Various approaches of optimizing
the mold cooling circuit have been proposed previously. In this work, optimization of the mold cooling circuit was automated
by a commercial process integration and design optimization tool called Process Integration, Automation and Optimization (PIAnO),
which is often used for large automotive parts such as bumpers and instrument panels. The cooling channels and baffle tubes
were located on the offset profile equidistant from the part surface. The locations of the cooling channels and the baffle
tubes were automatically generated and input into the mold cooling computer-aided engineering program, Autodesk Moldflow Insight
2010. The objective function was the deviation of the mold surface temperature from a given design temperature. Design variables
in the optimization were the depths, distances and diameters of the cooling channels and the baffle tubes. For a more practical
analysis, the pressure drop and temperature drop were considered the limited values. Optimization was performed using the
progressive quadratic response surface method. The optimization resulted in a more uniform temperature distribution when compared
to the initial design, and utilizing the proposed optimization method, a satisfactory solution could be made at a lower cost. 相似文献
996.
The importance of specifying and quantifying the project risks in the investment decision process cannot be overemphasized. Even more so in the context of marine project appraisal, since the shiping markets are characterized by extreme volatility and high cyclicality. The use of probability theory in investment decisions is reviewed and applications are derived for marine projects. The paper focuses on the use of Monte Carlo simulation to determine the mean and variance of the input variables. Within the Monte Carlo framework three alternative methods are used for the construction of probability distributions; the scaled halves of a normal distribution, two unscaled parts of a normal distribution and finally use of altenative distributions, such as beta, gamma and chi-square. An alternative methodology is also drawn from the literature, namely the Pearson-Turkey three point approximation, to contrast with the Monte Carlo method. 相似文献
997.
N. Shashikumar 《Maritime Policy and Management》1989,16(1):13-26
The US Shipping Act of 1984 permits ocean liner vessel operators and shippers to make use of service contracts to further their mutual interests. However, starting from the very day this novel provision was incorporated into the Act, it has remained as a bone of contention between shippers and carriers serving US trade routes. This article highlights the major issues that have sprouted subsequent to the introduction of service contracts in ocean liner shipping. The author concludes with some logical suggestions to fine-tune the Act, without interfering with its legislative framework. 相似文献
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