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991.
M. M. Elmadany M. A. Dokainish A. B. Allan 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1979,8(4):287-316
This paper presents a review of the available literature describing the methods of modelling the vibrational response of articulated vehicles to the road inputs at the tire contact points. It states and discusses the mathematical techniques that have been put forward for obtaining road input characteristics, for modelling the vehicles in a range of degrees of freedom, and for performing the analysis necessary to obtain the vibrational response. Finally the indices that have been proposed for ride comfort and ride safety are given and the manner in which various researchers relate these to the vibrational characteristics of the vehicles is described. 相似文献
992.
Analytical Tire Models for Dynamic Vehicle Simulation 总被引:4,自引:0,他引:4
K. M. Captain Manager A. B. Boghani Program Manager D. N. Wormley Professor of Mechanical Engineering 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1979,8(1):1-32
Four basic tire models suitable for dynamic vehicle simulation are formulated. The models are compared through a six-degree-of-freedom nonlinear simulation of a cargo truck crossing rough ground. Guidelines are developed for the selection of an optimum tire model for a given dynamic vehicle simulation. 相似文献
993.
A. F. Daughety 《Transportation Research Part B: Methodological》1979,13(4):281-288
This paper provides a unifying framework for micro-based models of freight transport demand. An expected utility of profits model is posed that clarifies the conditions under which a system of equations (continuous) regression model should be used as opposed to the conditions that make a quantal choice model appropriate. The model also indicates the nature of subjective data that is necessary for estimating demand. In general, the conditions that give rise to the appropriate use of a quantal choice model imply that the needed subjective information is completely contained in the subjective probability distributions on the service characteristics; the utility function itself is irrelevant. 相似文献
994.
A new generation conical spray system for conventional diesel engines or premixed combustion diesel engines is introduced. By means of oriented impingement method, flexible spray penetration in design is realized. High-speed photograph was used to investigate the spatial distribution characteristics of the new spray for cases of different impingement angles and needle valve opening pressures. The results show that, by applying spray impingement orientation, fuel jets spread along the cone surface as shape of sectors, so the dispersion of jets is increased obviously. Changing on impingement angle leads to variation of penetration, which is critical in homogeneous mixture preparation. Due to the flexibility of spray penetration in design, the spray impingement on liner is avoided in a great extent. The results also indicate that higher needle valve opening pressure results in longer penetration and larger spray angle after impingement. Combustion characteristics of the impinged conical spray were studied in the 1135 type diesel engine. The new impinged conical spray system work smoothly in full load range with better fuel economy and lower emissions of NOx and soot than the original test engine. 相似文献
995.
XIAO Bin YANG Tie-Jun LIU Zhi-Gang 《船舶与海洋工程学报》2005,4(4):34-42
In this paper, the reduced-order modeling (ROM) technology and its corresponding linear theory are expanded from the linear dynamic system to the nonlinear one, and H∞ control theory is employed in the frequency domain to design some nonlinear system' s pre-compensator in some special way. The adaptive model inverse control (AMIC)theory coping with nonlinear system is improved as well. Such is the model reference adaptive inverse control with pre-compensator (PCMRAIC). The aim of that algorithm is to construct a strategy of control as a whole. As a practical example of the application, the nunlerical simulation has been given on matlab software packages. The numerical result is given. The proposed strategy realizes the linearization control of nonlinear dynamic system. And it carries out a good performance to deal with the nonlinear system. 相似文献
996.
A. S. Koraim 《Journal of Marine Science and Technology》2011,16(3):331-342
The performance of a slotted breakwater consisting of one row of vertical slots was investigated theoretically and experimentally
under normal regular waves. A simple theoretical model based on an eigenfunction was developed. The wave transmission, reflection,
energy loss, and hydrodynamic force exerted on the breakwater were calculated for different values of the wave and structure
parameters. The validity of the theoretical model was examined by comparing its results with theoretical and experimental
results obtained from different studies. It was found that the transmission coefficient decreases with increasing dimensionless
wavenumber (kh), increasing wave steepness (H
i/L), and decreasing breakwater porosity (ε). The reflection coefficient showed the opposite trend to the transmission coefficient. Also, about 20–50% of incident wave
energy was lost due to the effect of the breakwater. In addition, the proposed theoretical model can be used for predicting
the performance of slotted breakwaters and the hydrodynamic forces exerted on these structures using the friction coefficient
f = 1.5. 相似文献
997.
Long-term variability of the biogeochemical properties during the formation of central waters in the Eastern North Atlantic were analyzed between 42–47°N and 10–20°W from the dataset gathered during the Galicia VII (GVII) and C. Darwin 58/59 (CD58/59) cruises. These cruises that showed important changes in the thermohaline properties and the nutrient abundance of the upper layers were carried out under contrasting conditions of the North Atlantic Oscillation (NAO) index. The different climate forcing led a meridional shift of the transition zone between the formation regions of subpolar and subtropical Eastern North Atlantic Central Water (ENACWp and ENACWt, respectively). This displacement conditioned the presence of each ENACW in the study region and so the thermohaline and biogeochemical properties. The effect of the observed variability at decadal scale on the air–sea CO2 gradient (ΔfCO2) and exchange (FCO2) was analyzed using 1D model approach throughout 11 weekly-steps that simulated the development of a spring bloom during the shoaling of the mixed layer. The outputs of the model showed an intensification of the ocean CO2 uptake due to higher biological CO2 drawdown, during positive NAO conditions and its weakening under negative NAO influence. 相似文献
998.
999.
In this paper, we propose a novel polling algorithm to decrease the number of idle slots and collission slots during the polling
cycle by evaluating the bandwidth request of the subscribe stations (SSs) in the next polling cycle for broadband wireless
access (BWA) systems. We firstly analyze the feature of silent time intervals and deduce the Hurst index which symbolizes
the degree of self-similarity and long-relative nature. Then we represent the inactive OFF time intervals by the Pareto model
and estimate the shape parameter α by the group measured data. Finally we can evaluate the transmission probability of a silent SS before the next polling cycle.
By this algorithm, we can find the optimal transmission opportunities for the base station (BS) to achieve the least collision
or void timeslots in order to achieve the largest bandwidth efficiency. The theoretical analysis and simulation results show
that this polling algorithm can improve the performance for BWA system. 相似文献
1000.
Matteo Del Chicca 《WMU Journal of Maritime Affairs》2012,11(1):83-93
Before searching for new legal solutions to manage maritime piracy problems, especially those related to jurisdiction, it
is essential to examine and analyse the existing international legal framework to determine whether current international
legal instruments are already appropriate to face off this threat. One such principle is the “Aut dedere aut iudicare” principle, which has been also codified into SUA Convention, at art. 6 par. 4. This obligation comes from an international
treaty, so it cannot be disregarded by any state (short of becoming susceptible to international liability), neither can it
be amended by a national law. If a state party has inadequate law resources to establish its jurisdiction, or if unable or
unwilling to prosecute the pirate, then such state party has no choice but extradite the pirate. If we consider the above
principle as a conventional obligation, then it should be limited only to state parties, and it should be applied only under
conditions stated by SUA Convention. Instead, if we consider it as a customary law principle, because piracy—as crimen iuris gentium—offends international community as a whole, then such principle shall be binding without any limit or condition. 相似文献