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101.
There is a growing literature that promotes the presence of a mix of compensatory and semi-compensatory processing strategies
in the way that individuals evaluate packages of attributes in real or hypothetical markets, and make choices. This paper
proposes a specification for the utility form in a choice model to test if, given a pair of attributes with a common-metric
(e.g., components of travel time or cost), the attribute with the dominating level defines the marginal (dis)utility that
is assigned to both attributes. We refer to this processing strategy as a parameter transfer rule. We use a stated choice
data set, in the context of car driving individuals choosing between tolled and non-tolled routes, to estimate a mixed logit
model which incorporates the presence of the parameter transfer rule and the conventional fully compensatory rule, both existing
up to a probability. We find that if this parameter transfer heuristic is part of the mix, the WTP is more than 30% higher,
on average, than when only a fully compensatory rule is imposed. We also contrast the parameter transfer rule with other semi-compensatory
heuristics which have been investigated in other papers, and show that the finding adds further support to the accumulating
evidence that a semi-compensatory attribute processing rules tend to result in higher mean WTP estimates compared to the fully
compensatory attribute processing rule. 相似文献
102.
A. E. Ismail A. K. Ariffin S. Abdullah M. J. Ghazali 《International Journal of Automotive Technology》2011,12(2):225-232
An assessment was carried out herein to study the eccentricity of cracks subjected to mixed-mode loadings. Several loading
locations relative to a central line were selected to induce mixed-mode loadings, which were computed using a finite element
method. An adaptive meshing technique was adopted during the simulation of crack propagation to ensure the singularity of
stress at the tip of the crack. The stress intensity failure criterion was used and programmed, and the node splitting technique
was used when the stress intensity factor reached the fracture toughness of the material to simulate crack propagations. It
was found that large variations in the stress intensity factor were observed when off-set cracks were used, and that K
II
decreased when loading distance increased, but increased when the off-set crack distance was increased. Both crack eccentricity
and loading distance played important roles in producing mixed-mode loading, compared to the influence of central cracks.
Correction factors were introduced to modify the calculation of stress intensity factors under mixed-mode loadings. Simulations
of crack propagation were also conducted to study the effects of crack eccentricities and loading distances. It was found
that the crack length, the loading distance relative to the central crack and the crack eccentricity dominated calculations
of the integrity of cracked structures. 相似文献
103.
C. -H. Lee 《International Journal of Automotive Technology》2008,9(3):317-322
High speed and sport utility vehicles with large joint articulation angle demand lower friction in automotive driveshaft joints
to meet noise and vibration comfort levels. Thus a more thorough understanding of internal friction characteristics and mechanisms
is required. In this paper, a friction model in automotive driveshaft joints was developed through the use of test data from
an instrumented Constant Velocity (CV) joint friction apparatus with actual driveshaft assemblies. Experiments were conducted
under different realistic operating conditions of oscillatory speeds, CV joint articulation angles, lubrication, and torque.
The experimental data was used to develop a physics-based semi-empirical CV joint internal friction model as a function of
different CV joint operating parameters. It was found that the proposed friction model captures the experimental results well.
Also the friction model estimates the generated axial force (GAF) in tripod CV joints well, which is the main source of force
that causes vehicle vibration problems. 相似文献
104.
105.
Kailin Kroetz Daniel K. Lew James N. Sanchirico Pierce Donovan 《Coastal management》2019,47(2):207-226
The Pacific Halibut Catch Sharing Plan formalized the process for allocating halibut between the Alaska commercial and recreational charter sectors. It included a new program intended to allow for “flexibility” through inter-sectoral trading, permitting charter operators to lease commercial halibut pounds to relax client harvest restrictions. Here we evaluate the first two years of lease market activity and participation. Participation from some commercial quota holders in the lease market suggests that the program provided beneficial flexibility; in fact, the number of transfers to the charter sector was greater than transfers within the commercial sector for some quota types. We also identified a high proportion of self-leasers. However, transfers to the charter sector were on average smaller than within-sector commercial transfers, and total poundage leased by the charter sector was low compared with commercial transfers. Usage of leased quota by the recreational charter sector enables the harvest of larger fish or additional fish, and provides flexibility in catch composition on halibut closure days. Finally, the value-per-pound may be higher in the charter sector, as commercial-to-charter transfer prices approached the commercial ex-vessel price. 相似文献
106.
The galvanic corrosion behavior of the metal combinations 15 CDV6/MDN138 and 15 CDV6/MDN250, with 1:1 area ratio, has been studied in natural seawater using the open well facility of CECRI's Offshore Platform at Tuticorin for a year. The open circuit potentials of MDN138, MDN250, and 15 CDV6 of the individual metal, the galvanic potential and galvanic current of the couples 15 CDV6/MDN138 and 15 CDV6/MDN250, were periodically monitored throughout the study period. The calcareous deposits on MDN138 and MDN250 in galvanic contact with 15 CDV6 were analyzed using XRD. The electrochemical behavior of MDN138, MDN250, and 15 CDV6 in seawater was studied using an electrochemical work station. The surface characteristics of MDN138 and MDN250 in galvanic contact with 15 CDV6 have been examined with a scanning electron microscope. The results of the study reveal that the galvanic protection offered by15 CDV6 to MDN250 and MDN138 in natural seawater amounts to 93% and 98%, respectively, implying that the galvanic protection offered by 15 CDV6 is continuous and effective, which has been further evinced from the adherent nature of the calcareous deposit film comprising compounds such as CaCO_3(calcite, aragonite, and vaterite), MgCO_3(magnesite),Mg(OH)_2(brucite), and MgO(brucite). 相似文献
107.
Development of a low-noise cooling fan for an alternator using numerical and doe methods 总被引:1,自引:0,他引:1
W. Kim W. -H. Jeon N. Hur J. -J. Hyun C. -K. Lim S. -H. Lee 《International Journal of Automotive Technology》2011,12(2):307-314
An alternator, which converts mechanical rotational energy into electrical energy, is an important component of a vehicle.
Alternators operate over a broad range of rotational speeds, typically from 3,000 RPM to 18,000 RPM, which demands a cooling
fan producing sufficient airflow, ideally with a minimum of noise. In the current study, an optimized alternator-cooling fan
was developed through a linked DOE(Design OF Experiment) process and numerical analysis. The SC/Tetra and FlowNoise S/W programs were used to calculate flow rates and noise levels, respectively, for the newly developed fan. Compared with
original model, the numerical results predicted a 3 dBA noise reduction; the measured reduction was 4 dBA. 相似文献
108.
H. G. Zhang E. H. Wang B. Y. Fan M. G. Ouyang S. Z. Xia 《International Journal of Automotive Technology》2011,12(2):173-182
Variable Nozzle Turbocharger (VNT) was invented to solve the problem of matching an ordinary turbocharger with an engine.
VNT can harness exhaust energy more efficiently, enhance intake airflow response and reduce engine emissions, especially during
transient operating conditions. The difficulty of VNT control lies in how to regulate the position of the nozzle at different
engine working conditions. The control strategy designed in this study is a combination of a closed-loop feedback controller
and an open-loop feed-forward controller. The gain-scheduled proportional-integral-derivative (PID) controller was implemented
as the feedback controller to overcome the nonlinear characteristic. As it is difficult to tune the parameters of the gain-scheduled
PID controller on an engine test bench, system identification was used to identify the plant model properties at different
working points for a WP10 diesel engine on the test bench. The PID controller parameters were calculated based on the identified
first-order-plus-dead-time (FOPDT) plant model. The joint simulation of the controller and the plant model was performed in
Matlab/Simulink. The time-domain and frequency-domain performances of the entire system were evaluated. The designed VNT control
system was verified with engine tests. The results indicated that the real boosting pressure traced the target boosting pressure
well at different working conditions. 相似文献
109.
J. H. Yoon B. J. Choi I. H. Yang J. E. Oh 《International Journal of Automotive Technology》2011,12(1):59-66
T-Hypoid gears are commonly used in rear-drive and 4WD (4 Wheel Drive) vehicle axles. Investigating their sensitivity to deflections
is one of the most important aspects of their design and optimization procedures. Therefore, a deflection test was performed
in this study in the actual gear mounting using completely processed gear. This test covered the full operating range of gear
loads from “no load” to “peak load”. Under peak load, the contact pattern extended to the tooth boundaries without showing
a concentration of the contact pattern at any point on the tooth surface. The transmission error was tested under an axle
assembly triaxial-real-car-load condition. 相似文献
110.
B. J. Yoon J. Y. Lee J. H. Kim C. S. Han 《International Journal of Automotive Technology》2011,12(1):111-118
A navigation algorithm is indispensable for Unmanned Ground Vehicles (UGVs). During driving, UGVs follow a global path. In
this study, we propose a navigation algorithm using Real Time Kinematic (RTK)-Differential Global Positioning System (DGPS)
units and encoders to complement global path planning. Sometimes GPS systems lose their signals and receive inaccurate position
data due to many factors, such as edifice and barrier obstructions. This paper shows that GPS deviations can be solved using
a Dead Reckoning (DR) navigation method with encoders and that position errors can be decreased through the use of RTK-DGPS
units. In addition to this method, we will introduce a new waypoint update algorithm and a steering algorithm using RTK-DGPS
units. 相似文献