29 research outputs found
Demystifying Dependency Bugs in Deep Learning Stack
Deep learning (DL) applications, built upon a heterogeneous and complex DL
stack (e.g., Nvidia GPU, Linux, CUDA driver, Python runtime, and TensorFlow),
are subject to software and hardware dependencies across the DL stack. One
challenge in dependency management across the entire engineering lifecycle is
posed by the asynchronous and radical evolution and the complex version
constraints among dependencies. Developers may introduce dependency bugs (DBs)
in selecting, using and maintaining dependencies. However, the characteristics
of DBs in DL stack is still under-investigated, hindering practical solutions
to dependency management in DL stack. To bridge this gap, this paper presents
the first comprehensive study to characterize symptoms, root causes and fix
patterns of DBs across the whole DL stack with 446 DBs collected from
StackOverflow posts and GitHub issues. For each DB, we first investigate the
symptom as well as the lifecycle stage and dependency where the symptom is
exposed. Then, we analyze the root cause as well as the lifecycle stage and
dependency where the root cause is introduced. Finally, we explore the fix
pattern and the knowledge sources that are used to fix it. Our findings from
this study shed light on practical implications on dependency management
UWB Base Station Cluster Localization for Unmanned Ground Vehicle Guidance
In this paper, we seek to provide unmanned ground vehicles with positioning service using ultrawideband (UWB) technology, a high-accuracy positioning approach. UWB is chosen for two distinct reasons. First, it does not rely on global navigation satellite systems like GPS, making it able to be applied indoors or in an environment where GPS signal is unstable. Second, it is immune to interference from other signals and accurate enough to guide unmanned ground vehicles moving precisely in a complex environment within a narrow road. In this paper, three UWB base stations are aggregated as a group in a 2D space for localization. A large number of tests are performed with a UWB base station cluster in order to validate its positioning performance. Based on the experiment results, we further develop a dynamic particle swarm optimization-based algorithm and a genetic algorithm to deploy multiple clusters of UWB base stations to cover an area of interest. The performance of the proposed algorithms has been tested through a series of simulations. Finally, experiments using unmanned ground vehicles are carried out to validate the localization performance. The results confirm that the robots can follow complex paths accurately with the proposed UWB-based positioning system
Autonomous Last-Mile Delivery Based on the Cooperation of Multiple Heterogeneous Unmanned Ground Vehicles
With the development of e-commerce, the last-mile delivery has become a significant part of customers’ shopping experience. In this paper, an autonomous last-mile delivery method using multiple unmanned ground vehicles is investigated. Being a smart logistics service, it provides a promising solution to reduce the delivery cost, improve efficiency, and avoid the spread of airborne diseases, such as SARS and COVID-19. By using a cooperation strategy with multiple heterogeneous robots, contactless parcel delivery can be carried out within apartment complexes efficiently. In this paper, the last-mile delivery with heterogeneous UGVs is formulated as an optimization problem aimed at minimizing the maximum makespan to complete all tasks. Then, a heuristic algorithm combining the Floyd’s algorithm and PSO algorithm is proposed for task assignment and path planning. This algorithm is further realized in a distributed scheme, with all robots in a swarm working together to obtain the best task schedule. A good solution with an optimized makespan is achieved by considering the constraints of various robots in terms of speed and payload. Simulations and experiments are carried out and the obtained results confirm the validity and applicability of the developed approaches
Proteomic Analysis of Hylocereus polyrhizus Reveals Metabolic Pathway Changes
Red dragon fruit or red pitaya (Hylocereus polyrhizus) is the only edible fruit that contains betalains. The color of betalains ranges from red and violet to yellow in plants. Betalains may also serve as an important component of health-promoting and disease-preventing functional food. Currently, the biosynthetic and regulatory pathways for betalain production remain to be fully deciphered. In this study, isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomic analyses were used to reveal the molecular mechanism of betalain biosynthesis in H. polyrhizus fruits at white and red pulp stages, respectively. A total of 1946 proteins were identified as the differentially expressed between the two samples, and 936 of them were significantly highly expressed at the red pulp stage of H. polyrhizus. RNA-seq and iTRAQ analyses showed that some transcripts and proteins were positively correlated; they belonged to “phenylpropanoid biosynthesis”, “tyrosine metabolism”, “flavonoid biosynthesis”, “ascorbate and aldarate metabolism”, “betalains biosynthesis” and “anthocyanin biosynthesis”. In betalains biosynthesis pathway, several proteins/enzymes such as polyphenol oxidase, CYP76AD3 and 4,5-dihydroxy-phenylalanine (DOPA) dioxygenase extradiol-like protein were identified. The present study provides a new insight into the molecular mechanism of the betalain biosynthesis at the posttranscriptional level
The Jasmonate-ZIM Domain Proteins Interact with the R2R3-MYB Transcription Factors MYB21 and MYB24 to Affect Jasmonate-Regulated Stamen Development in Arabidopsis[C][W]
Jasmonate is essential for diverse biological processes, including male fertility and plant defense in Arabidopsis. This work shows that the R2R3-MYB transcription factors MYB21 and MYB24 function as direct targets of JAZ proteins to mediate jasmonate-regulated stamen development
The Jasmonate-ZIM-Domain Proteins Interact with the WD-Repeat/bHLH/MYB Complexes to Regulate Jasmonate-Mediated Anthocyanin Accumulation and Trichome Initiation in Arabidopsis thaliana[C][W]
This work examines the molecular mechanism of jasmonate regulation of anthocyanin biosynthesis and trichome initiation. It identifies three bHLH transcription factors and two MYB transcription factors as new targets of JAZ proteins, showing that JAZ proteins attenuate the transcriptional function of WD-repeat/bHLH/MYB complexes to regulate anthocyanin accumulation and trichome