6,704 research outputs found
Development of Computer Vision-Enhanced Smart Golf Ball Retriever
An automatic vehicle system was developed to assist golfers in collecting golf balls from a practice field. Computer vision methodology was utilized to enhance the detection of golf balls in shallow and/or deep grass regions. The free software OpenCV was used in this project because of its powerful features and supported repository. The homemade golf ball picker was built with a smart recognition function for golf balls and can lock onto targets by itself. A set of field tests was completed in which the rate of golf ball recognition was as high as 95%. We report that this homemade smart golf ball picker can reduce the tremendous amount of labor associated with having to gather golf balls scattered throughout a practice field
Channel Access Management in Data Intensive Sensor Networks
There are considerable challenges for channel access in Data Intensive Sensor Networks - DISN, supporting Data Intensive Applications like Structural Health Monitoring. As the data load increases, considerable degradation of the key performance parameters of such sensor networks is observed. Successful packet delivery ratio drops due to frequent collisions and retransmissions. The data glut results in increased latency and energy consumption overall. With the considerable limitations on sensor node resources like battery power, this implies that excessive transmissions in response to sensor queries can lead to premature network death. After a certain load threshold the performance characteristics of traditional WSNs become unacceptable. Research work indicates that successful packet delivery ratio in 802.15.4 networks can drop from 95% to 55% as the offered network load increases from 1 packet/sec to 10 packets/sec. This result in conjunction with the fact that it is common for sensors in an SHM system to generate 6-8 packets/sec of vibration data makes it important to design appropriate channel access schemes for such data intensive applications.In this work, we address the problem of significant performance degradation in a special-purpose DISN. Our specific focus is on the medium access control layer since it gives a fine-grained control on managing channel access and reducing energy waste. The goal of this dissertation is to design and evaluate a suite of channel access schemes that ensure graceful performance degradation in special-purpose DISNs as the network traffic load increases.First, we present a case study that investigates two distinct MAC proposals based on random access and scheduling access. The results of the case study provide the motivation to develop hybrid access schemes. Next, we introduce novel hybrid channel access protocols for DISNs ranging from a simple randomized transmission scheme that is robust under channel and topology dynamics to one that utilizes limited topological information about neighboring sensors to minimize collisions and energy waste. The protocols combine randomized transmission with heuristic scheduling to alleviate network performance degradation due to excessive collisions and retransmissions. We then propose a grid-based access scheduling protocol for a mobile DISN that is scalable and decentralized. The grid-based protocol efficiently handles sensor mobility with acceptable data loss and limited overhead. Finally, we extend the randomized transmission protocol from the hybrid approaches to develop an adaptable probability-based data transmission method. This work combines probabilistic transmission with heuristics, i.e., Latin Squares and a grid network, to tune transmission probabilities of sensors, thus meeting specific performance objectives in DISNs. We perform analytical evaluations and run simulation-based examinations to test all of the proposed protocols
WERE U.S. CROP YIELDS RANDOM IN RECENT YEARS?
Crop Production/Industries,
Critically Examining the "Neural Hype": Weak Baselines and the Additivity of Effectiveness Gains from Neural Ranking Models
Is neural IR mostly hype? In a recent SIGIR Forum article, Lin expressed
skepticism that neural ranking models were actually improving ad hoc retrieval
effectiveness in limited data scenarios. He provided anecdotal evidence that
authors of neural IR papers demonstrate "wins" by comparing against weak
baselines. This paper provides a rigorous evaluation of those claims in two
ways: First, we conducted a meta-analysis of papers that have reported
experimental results on the TREC Robust04 test collection. We do not find
evidence of an upward trend in effectiveness over time. In fact, the best
reported results are from a decade ago and no recent neural approach comes
close. Second, we applied five recent neural models to rerank the strong
baselines that Lin used to make his arguments. A significant improvement was
observed for one of the models, demonstrating additivity in gains. While there
appears to be merit to neural IR approaches, at least some of the gains
reported in the literature appear illusory.Comment: Published in the Proceedings of the 42nd Annual International ACM
SIGIR Conference on Research and Development in Information Retrieval (SIGIR
2019
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