39 research outputs found
Consensus of Multi-Agent Systems with General Linear and Lipschitz Nonlinear Dynamics Using Distributed Adaptive Protocols
This paper considers the distributed consensus problems for multi-agent
systems with general linear and Lipschitz nonlinear dynamics. Distributed
relative-state consensus protocols with an adaptive law for adjusting the
coupling weights between neighboring agents are designed for both the linear
and nonlinear cases, under which consensus is reached for all undirected
connected communication graphs. Extensions to the case with a leader-follower
communication graph are further studied. In contrast to the existing results in
the literature, the adaptive consensus protocols here can be implemented by
each agent in a fully distributed fashion without using any global information.Comment: 15 pages, 6 figures, submitted to IEEE TA
Unsupervised Multi-view Pedestrian Detection
With the prosperity of the video surveillance, multiple cameras have been
applied to accurately locate pedestrians in a specific area. However, previous
methods rely on the human-labeled annotations in every video frame and camera
view, leading to heavier burden than necessary camera calibration and
synchronization. Therefore, we propose in this paper an Unsupervised Multi-view
Pedestrian Detection approach (UMPD) to eliminate the need of annotations to
learn a multi-view pedestrian detector via 2D-3D mapping. 1) Firstly,
Semantic-aware Iterative Segmentation (SIS) is proposed to extract unsupervised
representations of multi-view images, which are converted into 2D pedestrian
masks as pseudo labels, via our proposed iterative PCA and zero-shot semantic
classes from vision-language models. 2) Secondly, we propose Geometry-aware
Volume-based Detector (GVD) to end-to-end encode multi-view 2D images into a 3D
volume to predict voxel-wise density and color via 2D-to-3D geometric
projection, trained by 3D-to-2D rendering losses with SIS pseudo labels. 3)
Thirdly, for better detection results, i.e., the 3D density projected on
Birds-Eye-View from GVD, we propose Vertical-aware BEV Regularization (VBR) to
constraint them to be vertical like the natural pedestrian poses. Extensive
experiments on popular multi-view pedestrian detection benchmarks Wildtrack,
Terrace, and MultiviewX, show that our proposed UMPD approach, as the first
fully-unsupervised method to our best knowledge, performs competitively to the
previous state-of-the-art supervised techniques. Code will be available
Halo: Estimation and Reduction of Hallucinations in Open-Source Weak Large Language Models
Large Language Models (LLMs) have revolutionized Natural Language Processing
(NLP). Although convenient for research and practical applications, open-source
LLMs with fewer parameters often suffer from severe hallucinations compared to
their larger counterparts. This paper focuses on measuring and reducing
hallucinations in BLOOM 7B, a representative of such weaker open-source LLMs
that are publicly available for research and commercial applications. We
introduce HaloCheck, a lightweight BlackBox knowledge-free framework designed
to quantify the severity of hallucinations in LLMs. Additionally, we explore
techniques like knowledge injection and teacher-student approaches to alleviate
hallucinations in low-parameter LLMs. Our experiments effectively demonstrate
the reduction of hallucinations in challenging domains for these LLMs
Boosting Multi-Modal E-commerce Attribute Value Extraction via Unified Learning Scheme and Dynamic Range Minimization
With the prosperity of e-commerce industry, various modalities, e.g., vision
and language, are utilized to describe product items. It is an enormous
challenge to understand such diversified data, especially via extracting the
attribute-value pairs in text sequences with the aid of helpful image regions.
Although a series of previous works have been dedicated to this task, there
remain seldomly investigated obstacles that hinder further improvements: 1)
Parameters from up-stream single-modal pretraining are inadequately applied,
without proper jointly fine-tuning in a down-stream multi-modal task. 2) To
select descriptive parts of images, a simple late fusion is widely applied,
regardless of priori knowledge that language-related information should be
encoded into a common linguistic embedding space by stronger encoders. 3) Due
to diversity across products, their attribute sets tend to vary greatly, but
current approaches predict with an unnecessary maximal range and lead to more
potential false positives. To address these issues, we propose in this paper a
novel approach to boost multi-modal e-commerce attribute value extraction via
unified learning scheme and dynamic range minimization: 1) Firstly, a unified
scheme is designed to jointly train a multi-modal task with pretrained
single-modal parameters. 2) Secondly, a text-guided information range
minimization method is proposed to adaptively encode descriptive parts of each
modality into an identical space with a powerful pretrained linguistic model.
3) Moreover, a prototype-guided attribute range minimization method is proposed
to first determine the proper attribute set of the current product, and then
select prototypes to guide the prediction of the chosen attributes. Experiments
on the popular multi-modal e-commerce benchmarks show that our approach
achieves superior performance over the other state-of-the-art techniques
Progress on Optical Fiber Biochemical Sensors Based on Graphene
Graphene, a novel form of the hexagonal honeycomb two-dimensional carbon-based structural material with a zero-band gap and ultra-high specific surface area, has unique optoelectronic capabilities, promising a suitable basis for its application in the field of optical fiber sensing. Graphene optical fiber sensing has also been a hotspot in cross-research in biology, materials, medicine, and micro-nano devices in recent years, owing to prospective benefits, such as high sensitivity, small size, and strong anti-electromagnetic interference capability and so on. Here, the progress of optical fiber biochemical sensors based on graphene is reviewed. The fabrication of graphene materials and the sensing mechanism of the graphene-based optical fiber sensor are described. The typical research works of graphene-based optical fiber biochemical sensor, such as long-period fiber grating, Bragg fiber grating, no-core fiber and photonic crystal fiber are introduced, respectively. Finally, prospects for graphene-based optical fiber biochemical sensing technology will also be covered, which will provide an important reference for the development of graphene-based optical fiber biochemical sensors
Research on Bell-Shaped Vibratory Angular Rate Gyro’s Character of Resonator
Bell-shaped vibratory angular rate gyro (abbreviated as BVG) is a new type Coriolis vibratory gyro that was inspired by Chinese traditional clocks. The resonator fuses based on a variable thickness axisymmetric multicurved surface shell. Its characteristics can directly influence the performance of BVG. The BVG structure not only has capabilities of bearing high overload, high impact and, compared with the tuning fork, vibrating beam, shell and a comb structure, but also a higher frequency to overcome the influence of the disturbance of the exterior environment than the same sized hemispherical resonator gyroscope (HRG) and the traditional cylinder vibratory gyroscope. It can be widely applied in high dynamic low precision angular rate measurement occasions. The main work is as follows: the issue mainly analyzes the structure and basic principle, and investigates the bell-shaped resonator’s mathematical model. The reasonable structural parameters are obtained from finite element analysis and an intelligent platform. Using the current solid vibration gyro theory analyzes the structural characteristics and principles of BVG. The bell-shaped resonator is simplified as a paraboloid of the revolution mechanical model, which has a fixed closed end and a free opened end. It obtains the natural frequency and vibration modes based on the theory of elasticity. The structural parameters are obtained from the orthogonal method by the research on the structural parameters of the resonator analysis. It obtains the modal analysis, stress analysis and impact analysis with the chosen parameters. Finally, using the turntable experiment verifies the gyro effect of the BVG
Frequency Split Elimination Method for a Solid-State Vibratory Angular Rate Gyro with an Imperfect Axisymmetric-Shell Resonator
The resonator of a solid-state vibratory gyro is responsible for sensing angular motion. Frequency splitting of an axisymmetric-shell resonator is a common problem caused by manufacturing defects. The defect causes a frequency difference between two working modes which consist of two nodes and two antinodes. The difference leads to the loss of gyroscopic effect, and thus the resonator cannot sense angular motion. In this paper, the resonator based on an axisymmetric multi-curved surface shell structure is investigated and an approach to eliminate frequency splits is proposed. Since axisymmetric multi-curved surface shell resonators are too complex to be modeled, this paper proposes a simplified model by focusing on a common property of the axisymmetric shell. The resonator with stochastic imperfections is made equivalent to a perfect shell with an imperfect mass point. Rayleigh’s energy method is used in the theoretical analysis. Finite element modeling is used to demonstrate the effectiveness of the elimination approach. In real cases, a resonator’s frequency split is eliminated by the proposed approach. In this paper, errors in the theoretical analysis are discussed and steps to be taken when the deviation between assumptions and the real situation is large are figured out. The resonator has good performance after processing. The elimination approach can be applied to any kind of solid-state vibratory gyro resonators with an axisymmetric shell structure
A Novel Calendar-Based Method for Visualizing Water Quality Change: The Case of the Yangtze River 2006–2015
Mapping water quality change is helpful in the study of the water environment of a region. Using visual methods, interpretation of water condition and pollution issues can be intuitive and easy to understand. In this paper, we present a map to represent the spatial and temporal variation of water quality change in the Yangtze River during the period from 2006 to 2015. The calendar view was developed to explore the water quality condition and water pollutants for sections of the Yangtze River. A “W” construction was proposed to arrange the weekly water quality data in a continuous logic, and qualitative colors were designed to identify the change in major pollutants throughout the period. This map provides a promising visual analytical approach to investigate the water quality status and reveal the spatial and temporal patterns of water quality change in the Yangtze River
Adaptive Pattern-Parameter Matching for Robust Pedestrian Detection
Pedestrians with challenging patterns, e.g. small scale or heavy occlusion, appear frequently in practical applications like autonomous driving, which remains tremendous obstacle to higher robustness of detectors. Although plenty of previous works have been dedicated to these problems, properly matching patterns of pedestrian and parameters of detector, i.e., constructing a detector with proper parameter sizes for certain pedestrian patterns of different complexity, has been seldom investigated intensively. Pedestrian instances are usually handled equally with the same amount of parameters, which in our opinion is inadequate for those with more difficult patterns and leads to unsatisfactory performance. Thus, we propose in this paper a novel detection approach via adaptive pattern-parameter matching. The input pedestrian patterns, especially the complex ones, are first disentangled into simpler patterns for detection head by Pattern Disentangling Module (PDM) with various receptive fields. Then, Gating Feature Filtering Module (GFFM) dynamically decides the spatial positions where the patterns are still not simple enough and need further disentanglement by the next-level PDM. Cooperating with these two key components, our approach can adaptively select the best matched parameter size for the input patterns according to their complexity. Moreover, to further explore the relationship between parameter sizes and their performance on the corresponding patterns, two parameter selection policies are designed: 1) extending parameter size to maximum, aiming at more difficult patterns for different occlusion types; 2) specializing parameter size by group division, aiming at complex patterns for scale variations. Extensive experiments on two popular benchmarks, Caltech and CityPersons, show that our proposed method achieves superior performance compared with other state-of-the-art methods on subsets of different scales and occlusion types