Fast 3D Collision Avoidance Algorithm for Fixed Wing UAS
JOURNAL OF INTELLIGENT & ROBOTIC SYSTEMS
Authors: Lin, Zijie; Castano, Lina; Mortimer, Edward; Xu, Huan
Abstract
This paper presents an efficient 3D collision avoidance algorithm for fixed wing Unmanned Aerial Systems (UAS). The algorithm increases the ability of aircraft operations to complete mission goals by enabling fast collision avoidance of multiple obstacles. The new algorithm, which we have named Fast Geometric Avoidance algorithm (FGA), combines geometric avoidance of obstacles and selection of a critical avoidance start time based on kinematic considerations, collision likelihood, and navigation constraints. In comparison to a current way-point generation method, FGA showed a 90% of reduction in computational time for the same obstacle avoidance scenario. Using this algorithm, the UAS is able to avoid static and dynamic obstacles while still being able to recover its original trajectory after successful collision avoidance. Simulations for different mission scenarios show that this method is much more efficient at avoiding multiple obstacles than previous methods. Algorithm effectiveness validation is provided with Monte Carlo simulations and flight missions in an aircraft simulator. FGA was also tested on a fixed-wing aircraft with successful results. Because this algorithm does not have specific requirements on the sensor data types it can be applied to cooperative and non-cooperative intruders.
Applying massively parallel sequencing to paternity testing on the Ion Torrent Personal Genome Machine
FORENSIC SCIENCE INTERNATIONAL-GENETICS
Authors: Li, Hui; Zhao, Xueying; Ma, Ke; Cao, Yu; Zhou, Huaigu; Ping, Yuan; Shao, Chengchen; Xie, Jianhui; Liu, Wenbin
Abstract
Massively parallel sequencing (MPS) is a promising supplementary method for forensic genetics and has gradually been applied to forensic casework. In this study, we applied MPS to forensic casework on an Ion Torrent Personal Genome Machine to evaluate its performance in paternity testing with mismatched STR loci. A total of 15 samples from seven cases containing one mismatched locus by capillary electrophoresis typing were analyzed. Combined paternity index (CPI) and relative chance of paternity were calculated according to the International Society for Forensic Genetics guidelines and the Chinese national standards recommended for paternity testing. With simultaneous analysis of enough STR loci, the results support the certainty of paternity, and the mismatched alleles were considered to be mutations (CPI > 10,000). With the detection of allele sequence structures, the origins of the mutations were inferred in some cases. Meanwhile, nine STRs (CSF1PO, D1S1656, D2S441, D2S1338, D3S1358, D8S1179, D12S391, D21S11 and D4S2408) were found in an increased number of unique alleles and three new alleles in three STRs (D2S441, D21S11, and FGA) that have not been reported before were detected. Therefore, MPS can provide valuable information for forensic genetics research and play a promising role in paternity testing.