Short‐term travel speed prediction models in car navigation systems

The objective of this study is the development of the short‐term prediction models to predict average spot speeds of the subject location in the short‐term periods of 5, 10 and 15 minutes respectively. In this study, field data were used to see the comparison of the predictability of Regression Analysis, ARIMA, Kalman Filtering and Neural Network models. These field data were collected from image processing detectors at the urban expressway for 17 hours including both peak and non‐peak hours. Most of the results were reliable, but the results of models using Kalman Filtering and Neural Networks are more accurate and realistic than those of the others.     

Analysis of Tire Effect on the Simulation of Vehicle Straight Line Motion

In the dynamic simulation of vehicle straight line motion, a vehicle model usually drifts from its intended straight path even in the case of no external input. This is particularly true when a tire model based on experimental data is used. The purpose of this paper is to provide an enhancement of a basic understanding of a tire/vehicle system behavior in the straight line motion and to identify the effect of the tire on that motion. Through the analysis of a two degrees of freedom vehicle model, tire characteristic which causes a lateral drift in the straight line motion is identified. Then the results are confirmed from vehicle test and the simulations with a more complex full-car model.     

A stability analysis of tandem offloading systems at sea

In this article, we analyze the linear stability of tandem offloading systems in wind, current, and waves. The wind and current forces are evaluated with the help of published experimental data, while the hydrodynamic coefficients and wave drift forces are rigorously estimated by using a three-dimensional singularity distribution method based on potential theory. The bow hawser and mooring lines are described quasistatically by elastic catenary equations. In order to examine the linear static and dynamic stability of the system, the equations for surge, sway, and yaw are linearized. The effect of design parameters such as turret position, mooring stiffness, and hawser length and stiffness on stability is investigated based on linearized model. The stability analysis clarifies the mechanism of the limit cycle for tandem offloading systems, which is known as fishtailing motion. The theoretical results of the shape and amplitude of the limit cycle are found to be in good agreement with those of simulations and experiments.     

Lessons from bankruptcy of Hanjin Shipping Company in chartering

This paper aims to analyze the charter contract management of major container shipping companies in response to fluctuations in shipping market conditions in terms of contract duration using data of containerships between 2010 and 2016. Duration analysis was conducted to examine the relationship between charter duration and shipping market conditions. Moreover, this paper explores the causes of Hanjin Shipping Company’s bankruptcy, drawing managerial implications. Test results from Cox PH (Proportional Hazard) model show that most container shipping companies in Europe having net earnings purchased large vessels instead of chartering vessels, while some ocean carriers featuring poor financial performance, in particular the Hanjin Shipping Company, chartered bigger ships with higher charter rates and longer duration. Contract charter rates and duration of Hanjin Shipping Company featured greater risk compared to competitors.     

Cooling and Heating Performance Improvement of Enhanced Climate Control Seats

The goal of this research is to investigate the application of low-cost climate control seats (CCSs) using a Heating, Ventilation and Air-conditioning system (HVAC). CCSs are being vigorously developed because demands on passengers’ thermal comfort are increasing recently. Nevertheless, current CCSs–thermo-electric devices (TED) that have been applied for both heating and cooling systems, have been used in limited luxury cars only. HVAC-type CCSs are proper for effective delivery of conditioned air due to thermal comfort and close proximity to passengers. In this study, experimental results show that HVAC-type CCSs have superior cooling performance and slightly worse heating performance than that of TED-type CCSs. In the case of HVAC-type CCSs, compared to TED-type CCSs, airflow volume was increased approximately 3.7–7.3 m³/h and surface temperature of seats was reduced by about 5 °C. And the maximum cool-down performance of HVAC-type CCSs was similar to the Base (Non HVAC-type CCSs). In addition, in passengers’ subjective evaluation, the HVAC-type CCSs, the former recorded twelve minutes to reach the comfort rate five both in cooling and heating test, meanwhile, TED-type CCSs are nineteen minutes and ten minutes each both in the cooling and heating test.     

Prediction of the maneuverability of a large container ship with twin propellers and twin rudders

The maneuvering characteristics of a large container ship with twin propellers and twin rudders were investigated using the horizontal planar motion mechanism (HPMM) test and computer simulation. A mathematical model for maneuvering motion with four degrees of freedom (DOF) for twin-propeller and twin-rudder systems was developed and included the effects of roll motion. To obtain the roll-coupling hydrodynamic coefficients of a container ship, a four-DOF HPMM system having a roll motion mechanism and a roll moment measurement system was used. At the full load condition, HPMM tests were carried out for two different 12 000-TEU container ship models, one with twin propellers and the other with a single propeller. Using the hydrodynamic coefficients obtained from the tests, computer simulations were carried out. Simulation results for the container ship with twin propellers and twin rudders were compared with the results for the container ship with a single propeller and single rudder.     

An Internal State Variable Model for the Low Temperature Tempering of Low Alloy Steels

QuanitativelyaccuratePredictionsofquenchinduceddistOnionandresidualstressrelyontheabilitytopredictthemicrosthectUralevolUtionthroughOutthequenchProcess.InlowaIloysteels,cUrrenresearchMshavefOcusedontheformationldneticsoffetrite,pearlite,bainiteandmartensite.However,temPeringcanhavealargeinfluenceondistOnionandresidualstrCss,andeffortstoaccountforthislagbehindthemodelingofthePrimnyphasetransihons.AsafirststeptowardsaccountingfortemPerillg,wehavedevelOpedanintemalstatevariablemodelthatuses…     

Comparison of Dynamic Models of Mr Damper for Hardware in the Loop Simulation of Large-Sized Buses

The present study has focused on the comparison of MR damper dynamic models for the purpose of hardware in the loop simulation. A vehicle dynamic model for large-sized bus and a control logic for MR damper was built. Two typical MR damper models, viz. Bouc-Wen and hyperbolic tangent model have been considered in this study and the advantages and disadvantages of each model on the aspect of HILS system is discussed. We discussed the limitations of each model based on the analysis of the vehicle dynamic simulation. The results showed that the existing models are not suitable for HILS system. We proposed the modified hyperbolic tangent model by adopting low-pass filters. The results from the simulation showed the advantages of the modified model which were validated through HILS system.     

Morphological Change and Number-Size Distributions of Particulate Matter (PM) from a Diesel Generator Operated with Wood Pyrolysis Oil-Butanol Blended Fuel

This report details our experimental study investigating particulate matter (PM) emissions from a diesel generator fueled with wood pyrolysis oil (WPO)–butanol blended fuel for electricity generation. Particle number-size distributions and PM mass concentrations from diesel, n-butanol, and WPO-butanol blended fuels were investigated via aerosol measurements using a fast mobility particle sizer and an aerosol monitor with three generator outputs (0, 3.3, and 6.6 kWe). For the n-butanol and WPO-blended fuels, the total number concentrations of exhaust particles were higher than that of conventional diesel combustion; however, the PM mass was observed to be nearly zero for all the engine operating conditions due to the higher number concentration in the nuclei mode. The morphology of the exhaust particles was investigated by analyzing transmission electron microscopy (TEM) micrographs. The morphology of the particles was drastically changed according to the test fuels and engine loads. Two types of particles were observed, including soot and coke shaped particles. These results were directly related to the immaturity of incipient soot particles due to the different physical properties and chemical compositions of the fuels.