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A new method is proposed for the identification of stiffness parameters for linear elastic structures subjected to static loads. The structural stiffnesses are identified at the element level utilizing forces and displacements measured on a subset of the degrees of freedom used to define the structural model. This method is capable of determining major changes in structural properties at the element level, including element failure. The effect of errors in force and displacement measurements are investigated utilizing a Monte Carlo analysis. This stochastic simulation may be performed prior to the actual test in order to establish an acceptable error limit for instrumentation. Also, this procedure provides important information regarding the best degrees of freedom to measure in order to identify a specific subset of the structural parameters.

The method of time series analysis is one of the most important time domain modal analysis techniques, however, its application to automotive experimental modal analysis is restricted by lack of an effective way to determine order of the time series model, By G-transformation, a new criterion for determination of model order is presented in this paper, so the obstacle is overcome. Besides, a new algorithm for estimation of time series model is presented and two kinds of models are used for identification of modal parameters, therefore the method of time series analysis can be applied better to automotive modal analysis. Last, an example of identifying automobile frame by our method is given. The identification results are better in conformity with the results of frequency domain method.

This study attempts to predict the effect of visual impairment from simulated levels of splash and spray on target vehicle identification distances. Five levels of hand held spray simulation frames were used to compare image digitization methods with visual performance (Snellen acuity or contrast sensitivity) assessment to predict a drivers ability to identify an oncoming target vehicle. The image digitization process was found to be highly correlated with actual target vehicle identification distances. Additionally, very high correlations were found between Snellen acuity and contrast sensitivity and identification distance. There did not seem to be any great difference in predictive power of either method of visual performance assessment over the other.

CRASH (Calspan Reconstruction of Accident Speeds on the Highway) is one of the primary tools used by the National Highway Traffic Safety Administration (NHTSA), U.S. Dept. of Transportation, for estimating the severity of impacts. It is a computer program which is used to estimate the velocity change (ΔV) of the centers of gravity of vehicles in an accident. This paper studies the validity of the linear ΔV vs. crush relationship used in CRASH3 for modern passenger cars. It describes the experimental work done to investigate the crush-energy vs. static crush for a number of models in side impacts. Finally, the crush-energy vs. residual crush behavior for a large number of vehicle models tested for NHTSA has been characterized and tabulated.

The CARDfile was developed by NHTSA to aid problem identification and countermeasure development in the field of crash avoidance research. This paper summarizes the results of an evaluation of selected CARDfile data elements. Many of the variables of interest to crash avoidance, such as precrash stability, rural/urban, roadway separation, avoidance attempt, and VIN, are entirely missing for one or more of the CARDfile states. Such non-random missing data are likely to bias the resulting distributions. Other examples are described of missing and incompatible code values. Although five of the six states appear to code precrash stability, in fact there is not a single category on this variable that is recorded in every state, and no single state has all the categories. Thus the CARDfile cannot reflect the true distribution of these attributes for the aggregate of the six states.

An integrated simulation model is described which characterizes the dynamic interaction of the energy transport subsystems of Space Station Freedom for given orbital conditions and for a given set of power and thermal loads. Subsystems included in the model are the Electric Power System (EPS), the Internal Thermal Control System (ITCS), the External Thermal Control System (ETCS), and the cabin Temperature and Humidity Control System (THC) (which includes the avionics air cooling, cabin air cooling, and inter-module ventilation systems). Models of the subsystems were developed in a number of system-specific modeling tools and validated. The subsystem models are then combined into integrated models to address a number of integrated performance issues involving the ability of the integrated energy transport system of Space Station Freedom to provide power, controlled cabin temperature and humidity, and equipment thermal control to support operations.

The initial goal of the Controlled Ecological Life Support System (CELSS) Breadboard Project is to develop and evaluate a ground-based bioregenerative system scaled to support the equivalent of one crew member. The Biomass Production Chamber (BPC) is the plant growing module of this project. We describe here the characterization of the microbial constituents of the BPC during production tests of hydroponically-grown crops of wheat and soybeans. Bacterial and fungal viable counts were determined for the hydroponic solution, dehumidifier condensate water, and atmosphere. Bacterial communities were characterized by taxonomic identification (Vitek AutoMicrobic System) of randomly selected isolates. For all crop tests, bacteria dominated the microflora of both the hydroponic solution (range--104 to 106 colony forming units [cfu] per mL), and dehumidifier condensate (103 to 106 cfu/mL).

IVHS, or Intelligent Vehicle Highway Systems, is a concept rapidly growing in momentum among government, industry, and academia for a variety of reasons. As a key component in the eventual deployment of IVHS technologies, the auto industry can be expected to support its contribution to reduced congestion, improved safety, energy conservation, environmental quality, and more pleasant car ownership. But a number of difficult problems must be solved before the car companies jump in with both feet, including marketability, cost (and resultant price), national and international infrastructure compatibility, assurance that necessary infrastructure will be provided (essentially a government responsibility), product liability concerns, confirmation of benefits, inability to deal with time horizons beyond five to seven years, and depressed economic conditions.

ADVANTAGE I-75 focuses on implementation of Intelligent Vehicle/Highway System (IVHS) technologies and on the processes whereby technological advancements are assimilated into the operational setting. ADVANTAGE I-75 represents a partnership of public and private interests in the I-75 corridor. Its goal is to reduce congestion, increase efficiency, and enhance safety of motorists and other users of I-75 and its connections into Canada through the application of advanced highway and vehicle technologies. Currently being considered as the inaugural project is an application of automatic vehicle identification (AVI) technology designed to facilitate motor-carrier operations by allowing transponder-equipped and properly documented trucks to travel any segment along the entire length of I-75 at mainline speeds with minimal stopping at enforcement stations.

In Canada, a national Intelligent Vehicle-Highway System [IVHS) - or Road Transport Informatics (RTI) or Advanced Telematics in Road Transport (ATRT) - program is under active development at present. To reach this stage, many parallel activities had to be pursued, particularly over the past four years. These have included research and demonstration projects on freeway traffic management systems and commercial fleet applications, state-of-the-art reviews of mobile systems technologies - and two major conferences, one on vehicle navigation and information systems, the other on automatic vehicle identification. This paper recalls some of the main events and progress made over this period and outlines current work in identifying Canadian invoLvement in the IVHS field. It is an update on a paper presented at the RTI/IVHS Conference of 24th ISATA (Florence, Italy, 20-24 May 19911 bringing into focus the most recent developments.

This paper focuses on current research efforts in the field of automatic vehicle identification (AVI) within the Heavy Vehicle Electronic License Plate (HELP) program. HELP is developing a commercial vehicle monitoring and management system integrating AVI with weigh-in-motion, automatic vehicle classification and a computerized communications network. A primary emphasis to date in the HELP program has been technology research and development, with AVI being central to this effort. Initial research, undertaken by CRC, has led to the development of a radio frequency based, open specification for an AVI system representing the technological state-of-the-art. However, in parallel with the HELP AVI research, the American Trucking Association (ATA) has recently adopted its own radio frequency identification (RFID) equipment standard. A new research effort is therefore being performed by CRC to develop compatible AVI standards meeting the requirements of both the ATA and HELP.

Electronic toll collection with reflective Automatic Vehicle Identification (AVI) tags in the vehicle windshield is a commercial reality, with proven reliability and cost effectiveness. Reflective tag technology enhances the selectivity for reading only the closest of several tags in the reader's field, as well as reducing tag complexity and cost. The advantages of reflective tag technology can be retained for the vehicle-to-roadside radio link of IVHS with a simple ASK radio link used for roadside-to-vehicle transmissions. System capability and reliability could be improved with the IVHS antenna designed into the vehicle structure. Usable vehicle speed and required RF power trade off against message length, making it necessary to use message data bits as efficiently as possible.

The problems of using existing automatic vehicle identification (AVI) systems for detection of vehicles on the busy city roads arise because physical barriers between lanes in the city toll sites are not desirable, while the traffic does not always comply with the lane disciplines. A new AVI system is described in this paper using the randomised time division multiplexing (TDM) technique for detecting several vehicles simultaneously entering the detection zone. Laboratory experiments carried out for up to 8 identification tags at the same time showed that all replies were detected for 900 interrogations. The collision of replying signals did not occur. The high speed transmission of serial data has, however, an error rate of 3 % - 7 %. Under the laboratory conditions, the detection errors were eliminated simply by allowing the tags to reply twice.

The feasibility study of using machine vision technology to locate corn plants was conducted to determine its potential in the development of an intelligent detasseling machine. A corn plant feature, the main vein of leaf, was used and the method of feature detection was developed for corn plant identification. Experimental results showed that the leaf feature and the center of the plant can be detected and located using image processing techniques when an image is taken from above of a plant. This research showed that it is possible to identify and locate the corn plant using machine vision technology.

Cable-mount dynamic wind-tunnel tests have been made in the NAL low speed wind tunnel for the purpose of extracting aerodynamic parameters of a 5% spaceplane model. The cable-mount dynamic wind-tunnel experiment is described. An identification technique composed of flight path reconstruction and regression analysis(two step method), and the maximum likelihood method for the identification of the parameters in the linear dynamic system(one step method) were applied to the wind-tunnel test data. The estimation results for the aerodynamic parameters by the two methods are compared.

The VS engines for the new Mercedes-Benz S-class first shown to the public at the Geneva Motor Show in March 1991 are, in terms of their basic mechanical design, identical to the 5-litre V8 engine familiar from the 500 SL. In addition, a 4.2-litre engine has been developed on the same mechanical basis, which rounds off the performance range at the lower end. The deck height of the crankcase of both engines is the same and has been reduced compared to the SL engine. This has made it possible to standardize exhaust manifolds, intake pipes, major assembly mountings and a large number of parts for the 4.2-litre and 5-litre versions and thus facilitates their production and assembly. Electronic fuel injection with air mass sensor and cylinder-specific fuel metering is part of the new engine management system. A motor-driven throttle valve is used for the first time for air management, which at the same time controls and stabilizes engine speed.

The X-29A forward-swept wing flight research aircraft flight envelope was expanded to 66°-angle of attack in 1990. This work was accomplished at the NASA Dryden Flight Research Facility in Edwards, California, using Grumman aircraft and United States Air Force personnel assistance. The flight envelope expansion was accomplished through a carefully planned buildup approach using the number 2 X-29 aircraft and a well documented high-angle-of-attack database established from wind-tunnel results, radio controlled subscale drop model results, and from previous X-29 aircraft number 1 flight data below 22.5°-angle of attack. Following the flight envelope expansion, a military utility evaluation was conducted to investigate the tactical utility of the X-29 configurations at high-angle-of-attack, slow-speed flight conditions.

A program of development and experimental validation of a multidimensional spray prediction method, based on the discrete droplet model, has been broadened to include computational investigations of the effects of random perturbations of the injection velocity on the spray characteristics, and further detailed examination of the spray structure and development. The results demonstrate strong dependence of the predicted spray penetration length on the precise start-of-injection time and injection velocity data, and relative insensitivity to subsequent variations of the injection velocity. Specifically, it is found that under imposition of random variations of the injection velocity, the variation of the spray-tip penetration and velocity remain smooth, bearing no correspondence to the instantaneous spray injection velocity.

Over the years the brake system of a passenger car was considered satisfactory if it met regulatory requirements. Meeting stopping distance at specified pedal efforts would declare the vehicle to be safe on roads. But beyond meeting safety requirements, the brake system response to pedal input is also important. This paper presents a case study where in the brake system met the regulatory norms, but subjective pedal feel and response was poor. This anomaly of subjective behavior was analyzed and correlated to the objective performance on the vehicle. Subsequent to this, the contribution of controllable parameters for good pedal feel was investigated. The investigations have led to identification of parameters that are critical in achieving optimal balance of performance and subjective feel. The results presented highlight the order of merit of the various components

The road impact load and the vibration are the main factors for the commercial vehicle, especially on the van trailer. In this paper, a new method which puts the operating modal identification and power spectrum density (PSD) analysis together was presented. The analysis results coincided with the road test quite well. The power spectrum response was obtained and the fatigue life of the vehicle was also estimated. This method can be used for the vibration optimization design and a random fatigue design of other commercial vehicles.