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Traction control (TC) systems have become quite common in on-road passenger vehicles in recent years. However, for vehicles in other applications, they are not as widely available.This work presents a methodology for the proper design and implementation of a traction control system for heavy duty off-road machines, using a wheel loader as a reference vehicle.A simulation model was developed, using standard vehicle dynamics constructs, including equations of motion and a description of the distribution of weight between the axles for different operating conditions. This model contains considerations for resistive forces acting on the machine implement, such as that generated by a work pile. The simulation also incorporates a detailed representation of the slip-friction characteristics between the vehicle tires and the road surface. One objective of this research was to model this interaction accurately, because the system traction behavior is dependent on it. Therefore, a series of tests was run using a state estimator to generate data on the slip-friction relationship at various ground conditions, and the results were incorporated into the simulation model. The dynamics of the machine braking system pressure were also modeled to give a more accurate description of the system response. The result is a mathematical model capable of accurately reproducing the behavior of the real-world system.One of the primary goals of this work was the description of the traction control strategy itself, which should work as effectively and efficiently as possible. Several different aspects of the system were taken into consideration in generating this control structure. First, a relatively simple controller based on a PID control law was created. This controller was updated to account for peculiarities of the traction control system, as well as aspects like time delay. From there, more advanced controllers were created to address certain aspects of the system in greater detail. First, a self-tuning controller based on real-time optimization strategies was developed, to allow the controller to quickly adapt to changes in ground condition. Then, different nonlinear controllers were synthesized which were designed to address the theoretical behavior of the system. All of these controllers were simulated using the system model and then some were run in experiments to show their potential for improving system performance. To improve system efficiency, the machine drivetrain itself was also examined to develop a more efficient control algorithm. By designing a more efficient methodology, traction control con gurations which had previously seen increases in fuel consumption of 16% were now able to actually reduce fuel usage by 2.6%.Another main goal of this work was the development of a prototype system capable of implementing the formulated control strategies. The reference machine was modi ed so that the brakes could be controlled electronically and independently for implementation of the TC system. The vehicle was instrumented using a wide array of sensors, and estimation methodologies for accurately determining vehicle speed and implement forces were designed. The velocity estimator designed in this work is more accurate and more reliable than an industry standard sensor, which is important for traction control implementation. The implement force estimate was also quite accurate, achieving payload estimate errors of less than 2.5%, comparable to commercially-available measurement systems. This setup allowed for tests to be accurately compared, to assess the traction control performance.With the objective of performing experiments on the traction control system, many tests were run to assess its capabilities in various situations. These tests included experiments for characterizing the vehicle behavior so that the simulation model could be updated to accurately reflect the physical machine performance. Another task for the experimental work was the generation of useful metrics for quantifying traction control performance. Laboratory experiments which were very controlled and repeatable were also run for generating data to improve the system model and for comparing traction control performance results side-byside. The test metrics proposed for these experiments provided for accurate, repeatable comparisons of pushing force, tire wear, and brake consumption. For each of these tests, the traction control system saw an increase in pushing force of at least 10% when compared with the stock machine, with certain operating conditions showing increases as high as 60%. Furthermore, every test case showed a decrease in wheel slip of at least 45% (up to 73% for some cases), which translates into increased tire longevity.Other tests were conducted in the eld, designed to mimic the real-world operating conditions of the wheel loader. Various performance comparisons were made for different con gurations in which traction control could provide potential bene ts. These included parameters for comparing overall vehicle performance in a typical truck loading cycle, such as tire wear, fuel consumption, and material moved per load. Initial results for this testing showed a positive result in terms of wheel slip reduction, but other performance parameters such as fuel consumption were negatively impacted. Therefore, the control structure was reexamined extensively and new methods were added to improve those results. The final control implementation saw a 12% reduction in tire slip, while also reducing fuel consumption by 2.6% compared to the stock system. These results show signi cant potential for traction control as a technology for maximizing the performance output of construction machines.

We report the discovery of TOI-677 b, first identified as a candidate in light curves obtained within Sectors 9 and 10 of the Transiting Exoplanet Survey Satellite (TESS) mission and confirmed with radial velocities. TOI-677 b has a mass of The host star has a mass of a radius of Gyr and solar metallicity, properties consistent with a main-sequence late-F star with K. We find evidence in the radial velocity measurements of a secondary long-term signal, which could be due to an outer companion. The TOI-677 b system is a well-suited target for Rossiter-Mclaughlin observations that can constrain migration mechanisms of close-in giant planets.

Understanding when, why, where, and how to use human factors methods is a key skill for human factors practitioners. Experienced professionals are very skilled at selecting methods appropriate to the task at hand, but the skill is a result of years of exposure. The current study examines the value of organizing human factors methods into a framework that relates and integrates information in meaningful ways to aid non-experts in selecting appropriate methods. The product design cycle is proposed as a viable framework for addressing this issue, though it is only one of many possible frameworks. Recommendations for future work include the development of additional frameworks targeting other audiences.

Objective: To determine whether broad-spectrum antibiotic therapy administered after a failed in vitro fertilization (IVF) cycle will improve the chance of achieving a successful pregnancy in the subsequent IVF cycle and to determine whether further antibiotic therapy administered immediately after conception, during the course of pregnancy, and at the time of delivery will reduce the incidence of maternal and fetal complications. Design: A retrospective analysis was performed on the clinical data of 63 couples who had previously failed one or more IVF cycles and were subsequently treated with broad-spectrum antibiotics. All women were treated with intravenous Clindamycin and daily intrauterine lavages using a broad-spectrum antibiotic combination. All men received intravenous Clindamycin and simultaneously underwent five direct transrectal injections of an antibiotic cocktail into the prostate gland if clinical or sonographic evidence of chronic prostatitis was documented. For both men and women...

In spite of their putative importance in the evolution of certain traits (e.g., nocturnality, coloniality, cliff nesting), the effects of aerial predators on behavior of adult seabirds at colonies have been poorly investigated. We hypothesized that Tufted Puffins (Fratercula cirrhata) respond to danger posed by aerial predators by modifying their behavior to mitigate danger. We observed Tufted Puffins making repeated colony fly-ins and departures and characterized (1) the timing of this behavior, (2) the activity rate (number of birds arriving or departing), and (3) the risk-level of activity, with respect to predation danger posed by Bald Eagles (Haliaeetus leucocephalus) and Peregrine Falcons (Falco peregrinus). As we predicted, we found that Tufted Puffins (1) dilute danger by synchronizing their fly-in and departure activities, (2) reduce fly-in and departure activity rates when predators are present, and (3) switch to lower-risk fly-in activities (e.g., staying over water where they have an escape route from an aerial attack) when predators are present.

This research deals with finite length, perfect reconstruction two-channel orthonormal wavelet filters. We have previously derived equations that allow the user to set the regularity of these filters to any value between one and the maximum possible. These equations were extremely involved and intricate. We derive identities that greatly simplify the equations and reduced computational complexity. We indicate how the equations may be used to find the optimum filter for a particular application over a pool of filters of regularity set by the user. We advance conjectures as to the theoretical significant of the structure of these equations and discuss numerical solutions.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

This research deals with finite length, perfect reconstruction two-channel orthonormal wavelet filters. For these filters, the coefficients of the filter of maximum order of regularity are unique and are known. Previous research has also developed a parameterizaiton to generate the coefficients of all filters of order of regularity one. The current research presents a parameterization for the generation of the coefficients of these filters with order of regularity between one and the maximum possible.