Mobile Vehicle Road And Weather Observation Quality Check Methods

Today State Departments of Transportation rely more and more on road weather data to make maintenance decisions. Inaccurate data can result in wrong treatment applications or inadequate staffing levels to maintain the roadway at the desired level of service. Previous methods of road condition data reporting have been limited to static in situ sensor stations. These road weather information systems (RWIS) provide varied data about precipitation, winds, temperature, and more, but their siting does not always provide an accurate representation of weather and road conditions along the roadway. The use of mobile data collection from vehicles travelling the highway corridors may assist in the locations where RWIS sitings are sparse or non-existent. The United States Department of Transporation\u27s Connected Vehicle (formally IntelliDrive) research project is designed to create a fully connected transportation system providing road and weather data collection from an extensive array of vehicles. While the implementation of Connected Vehicle is in the future, some of the theories and technologies are already in place today. Several states, as a part of the Pooled Fund Study Maintenance Decision Support System (MDSS), have equipped their winter maintenance vehicles with Mobile Data Collection Automated / Vehicle Location (MDC/AVL) systems. In addition, since 1996, automobiles sold in the United States are required to be equipped with an Onboard Diagnostic Version 2 (OBDII) port that streams live data from sensors located in and around the vehicle. While these sensors were designed for vehicle diagnostics, some of the data can be used to determine weather characteristics around the vehicle. The OBDII data can be collected by a smartphone and sent to a server in real time to be processed. These mobile systems may fill the information gap along the roads that stationary environmental sensor stations are not able to collect. Particular concern and care needs to be focused on data quality and accuracy, requiring the development of quality checks for mobile data collection. Using OBDII-equipped automobiles and mobile collection methods, we can begin to address issues of data quality by understanding, characterizing, and demonstrating the quality of mobile system observations from operational and research environments. Several forms of quality checking can be used, including range checks, Barnes spatial checks, comparing vehicle data to road weather models, and applying Clarus quality check methodologies and algorithms to mobile observations. Development of these quality checks can lead to the future integration of mobile data into the Clarus system, data implementation for improved forecasting, maintenance decision support, and traveler safety. This paper will discuss the benefits and challenges in mobile data collection, along with how the development and implementation of a system of quality checks will improve the quality and accuracy of mobile data collection

Trapping Set Enumerators for Repeat Multiple Accumulate Code Ensembles

The serial concatenation of a repetition code with two or more accumulators has the advantage of a simple encoder structure. Furthermore, the resulting ensemble is asymptotically good and exhibits minimum distance growing linearly with block length. However, in practice these codes cannot be decoded by a maximum likelihood decoder, and iterative decoding schemes must be employed. For low-density parity-check codes, the notion of trapping sets has been introduced to estimate the performance of these codes under iterative message passing decoding. In this paper, we present a closed form finite length ensemble trapping set enumerator for repeat multiple accumulate codes by creating a trellis representation of trapping sets. We also obtain the asymptotic expressions when the block length tends to infinity and evaluate them numerically.Comment: 5 pages, to appear in proc. IEEE ISIT, June 200

Plasmonic crystal demultiplexer and multiports

Artificially built periodic optical structures in dielectric and metallic media have generated considerable interest due to their potential for optical device miniaturization. In this context plasmonics, i.e., optics based on surface plasmon polaritons (SPPs) offers new exciting prospects. SPPs are hybrid light/electron surface waves at the interface between a dielectric and a metal and as such hold the potential for 2D optical functionality. Indeed, SPP elements as mirrors, splitters and interferometers have been recently demonstrated. However, for plasmonics to qualify at the information technology level requires necessarily the realization of wavelength division (demultiplexing) which constitutes a fundamental ingredient of optical communication. In the following we experimentally demonstrate 2D SPP demultiplexing in the visible spectral range by using photonic crystals for SPPs (plasmonic crystals). In addition, we demonstrate that plasmonic crystal are capable of realizing integrated linear multiports which could constitute building blocks of analog or quantum optical computing.Comment: Nano Lett.7, 1697 (2007

Plant Protection in organic production of Brassica vegetables and oilseed rape

Growers of organic Brassica vegetables and oilseed rape face the same potentially severe plant protection problems as their colleagues in conventional or integrated pest management systems.Management strategies in organic systems rely on preventive measures (crop rotation, crop isolation,soil management, host plant resistance, farm/field location; manipulate timing of planting or harvest; intercropping, mulching), use of functional agro-biodiversity (reduction of pest by enhancing natural enemies), release of biocontrol agents and a few approved pesticides of biological and mineral origin, as well as mating disruption or the use of anti-insect nets (Zehnder et al., 2007). The methods used in organic might also be applicable in IPM systems. However, several factors hamper wide implementation of these methods in IPM. Among the main reasons are (1) a lower efficacy compared to standard pesticide treatments, (2) higher costs, (3) lack of knowledge / information / advice on alternative methods, (4) inconvenience, and (5) the need for close collaboration between neighbouring famers to achieve good control. In the following paper, we describe the methods used in organic Brassica vegetable and oilseed rape production, and discuss their limitations

Multi-object tracking evaluated on sparse events

This article presents a visual object tracking method and applies an event-based performance evaluation metric for assessment. The proposed monocular object tracker is able to detect and track multiple object classes in non-controlled environments. The tracking framework uses Bayesian per-pixel classification to segment an image into foreground and background objects, based on observations of object appearances and motions in real-time. Furthermore, a performance evaluation method is presented and applied to different state-of-the-art trackers based on successful detections of semantically high level events. These events are extracted automatically from the different trackers an their varying types of low level tracking results. Then, a general new event metric is used to compare our tracking method with the other tracking methods against ground truth of multiple public dataset

Analysis and Design of Tuned Turbo Codes

It has been widely observed that there exists a fundamental trade-off between the minimum (Hamming) distance properties and the iterative decoding convergence behavior of turbo-like codes. While capacity achieving code ensembles typically are asymptotically bad in the sense that their minimum distance does not grow linearly with block length, and they therefore exhibit an error floor at moderate-to-high signal to noise ratios, asymptotically good codes usually converge further away from channel capacity. In this paper, we introduce the concept of tuned turbo codes, a family of asymptotically good hybrid concatenated code ensembles, where asymptotic minimum distance growth rates, convergence thresholds, and code rates can be traded-off using two tuning parameters, {\lambda} and {\mu}. By decreasing {\lambda}, the asymptotic minimum distance growth rate is reduced in exchange for improved iterative decoding convergence behavior, while increasing {\lambda} raises the asymptotic minimum distance growth rate at the expense of worse convergence behavior, and thus the code performance can be tuned to fit the desired application. By decreasing {\mu}, a similar tuning behavior can be achieved for higher rate code ensembles.Comment: Accepted for publication in IEEE Transactions on Information Theor

Biomechanics and energetics of walking in powered ankle exoskeletons using myoelectric control versus mechanically intrinsic control

Abstract Background Controllers for assistive robotic devices can be divided into two main categories: controllers using neural signals and controllers using mechanically intrinsic signals. Both approaches are prevalent in research devices, but a direct comparison between the two could provide insight into their relative advantages and disadvantages. We studied subjects walking with robotic ankle exoskeletons using two different control modes: dynamic gain proportional myoelectric control based on soleus muscle activity (neural signal), and timing-based mechanically intrinsic control based on gait events (mechanically intrinsic signal). We hypothesized that subjects would have different measures of metabolic work rate between the two controllers as we predicted subjects would use each controller in a unique manner due to one being dependent on muscle recruitment and the other not. Methods The two controllers had the same average actuation signal as we used the control signals from walking with the myoelectric controller to shape the mechanically intrinsic control signal. The difference being the myoelectric controller allowed step-to-step variation in the actuation signals controlled by the user’s soleus muscle recruitment while the timing-based controller had the same actuation signal with each step regardless of muscle recruitment. Results We observed no statistically significant difference in metabolic work rate between the two controllers. Subjects walked with 11% less soleus activity during mid and late stance and significantly less peak soleus recruitment when using the timing-based controller than when using the myoelectric controller. While walking with the myoelectric controller, subjects walked with significantly higher average positive and negative total ankle power compared to walking with the timing-based controller. Conclusions We interpret the reduced ankle power and muscle activity with the timing-based controller relative to the myoelectric controller to result from greater slacking effects. Subjects were able to be less engaged on a muscle level when using a controller driven by mechanically intrinsic signals than when using a controller driven by neural signals, but this had no affect on their metabolic work rate. These results suggest that the type of controller (neural vs. mechanical) is likely to affect how individuals use robotic exoskeletons for therapeutic rehabilitation or human performance augmentation.https://deepblue.lib.umich.edu/bitstream/2027.42/143850/1/12984_2018_Article_379.pd