| 1. |
- He, He, et al.
(författare)
-
Exploring community structure in networks by consensus dynamics
- 2016
-
Ingår i: Physica A. - : Elsevier. - 0378-4371 .- 1873-2119. ; 450, s. 342-353
-
Tidskriftsartikel (refereegranskat)abstract
- This paper investigates the relationship between community structure and consensus dynamics in complex networks. We analyze the dynamical process towards consensus and show that those sets of densely interconnected nodes corresponding to well-defined communities appear in different time scales. In order to reveal such topological scales, two algorithms built around the idea of visualizing the evolution of different measured quantities are proposed. Then we test our algorithms on a few benchmark graphs whose community structures are already known. Numeric simulations are given to demonstrate the effectiveness and reliability of our methods.
|
|
| 2. |
- Ge, Quanbo, et al.
(författare)
-
A Novel Adaptive Kalman Filter Based on Credibility Measure
- 2023
-
Ingår i: IEEE-CAA JOURNAL OF AUTOMATICA SINICA. - : Institute of Electrical and Electronics Engineers (IEEE). - 2329-9266. ; 10:1, s. 103-120
-
Tidskriftsartikel (refereegranskat)abstract
- It is quite often that the theoretic model used in the Kalman filtering may not be sufficiently accurate for practical applications, due to the fact that the covariances of noises are not exactly known. Our previous work reveals that in such scenario the filter calculated mean square errors (FMSE) and the true mean square errors (TMSE) become inconsistent, while FMSE and TMSE are consistent in the Kalman filter with accurate models. This can lead to low credibility of state estimation regardless of using Kalman filters or adaptive Kalman filters. Obviously, it is important to study the inconsistency issue since it is vital to understand the quantitative influence induced by the inaccurate models. Aiming at this, the concept of credibility is adopted to discuss the inconsistency problem in this paper. In order to formulate the degree of the credibility, a trust factor is constructed based on the FMSE and the TMSE. However, the trust factor can not be directly computed since the TMSE cannot be found for practical applications. Based on the definition of trust factor, the estimation of the trust factor is successfully modifled to online estimation of the TMSE. More importantly, a necessary and sufficient condition is found, which turns out to be the basis for better design of Kalman filters with high performance. Accordingly, beyond trust factor estimation with Sage-Husa technique (TFE-SHT), three novel trust factor estimation methods, which are directly numerical solving method (TFE-DNS), the particle swarm optimization method (PSO) and expectation max-imization-particle swarm optimization method (EM-PSO) are proposed. The analysis and simulation results both show that the proposed TFE-DNS is better than the TFE-SHT for the case of single unknown noise covariance. Meanwhile, the proposed EM-PSO performs completely better than the EM and PSO on the estimation of the credibility degree and state when both noise covariances should be estimated online.
|
|
| 3. |
- He, Xingkang, et al.
(författare)
-
Consistent Kalman filters for nonlinear uncertain systems over sensor networks
- 2020
-
Ingår i: Control Theory and Technology. - : Springer Nature. - 2095-6983 .- 2198-0942. ; 18:4, s. 399-408
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, we study how to design filters for nonlinear uncertain systems over sensor networks. We introduce two Kalman-type nonlinear filters in centralized and distributed frameworks. Moreover, the tuning method for the parameters of the filters is established to ensure the consistency, i.e., the mean square error is upper bounded by a known parameter matrix at each time. We apply the consistent filters to the track-to-track association analysis of multi-targets with uncertain dynamics. A novel track-to-track association algorithm is proposed to identify whether two tracks are from the same target. It is proven that the resulting probability of mis-association is lower than the desired threshold. Numerical simulations on track-to-track association are given to show the effectiveness of the methods.
|
|
| 4. |
- Kottyan, Leah C., et al.
(författare)
-
The IRF5-TNPO3 association with systemic lupus erythematosus has two components that other autoimmune disorders variably share.
- 2015
-
Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 24:2, s. 582-596
-
Tidskriftsartikel (refereegranskat)abstract
- Exploiting genotyping, DNA sequencing, imputation and trans-ancestral mapping, we used Bayesian and frequentist approaches to model the IRF5-TNPO3 locus association, now implicated in two immunotherapies and seven autoimmune diseases. Specifically, in systemic lupus erythematosus (SLE), we resolved separate associations in the IRF5 promoter (all ancestries) and with an extended European haplotype. We captured 3230 IRF5-TNPO3 high-quality, common variants across 5 ethnicities in 8395 SLE cases and 7367 controls. The genetic effect from the IRF5 promoter can be explained by any one of four variants in 5.7 kb (P-valuemeta = 6 × 10(-49); OR = 1.38-1.97). The second genetic effect spanned an 85.5-kb, 24-variant haplotype that included the genes IRF5 and TNPO3 (P-valuesEU = 10(-27)-10(-32), OR = 1.7-1.81). Many variants at the IRF5 locus with previously assigned biological function are not members of either final credible set of potential causal variants identified herein. In addition to the known biologically functional variants, we demonstrated that the risk allele of rs4728142, a variant in the promoter among the lowest frequentist probability and highest Bayesian posterior probability, was correlated with IRF5 expression and differentially binds the transcription factor ZBTB3. Our analytical strategy provides a novel framework for future studies aimed at dissecting etiological genetic effects. Finally, both SLE elements of the statistical model appear to operate in Sjögrens syndrome and systemic sclerosis whereas only the IRF5-TNPO3 gene-spanning haplotype is associated with primary biliary cirrhosis, demonstrating the nuance of similarity and difference in autoimmune disease risk mechanisms at IRF5-TNPO3.
|
|
| 5. |
- Li, Y., et al.
(författare)
-
Autonomous control and target tracking algorithm design for a quadrotor
- 2017
-
Ingår i: 2017 36th Chinese Control Conference (CCC). - : IEEE Computer Society. - 9789881563934 ; , s. 6749-6754
-
Konferensbidrag (refereegranskat)abstract
- In this paper, the task of Mission 7 of International Aerial Robotics Competition (IARC) is investigated. The quadrotor is required to autonomously navigate in a GPS-denied environment, and accomplish physical interaction with ground moving targets. In order to estimate the position of the quadrotor, a multi-sensor-compensation based method is designed and individual measurement errors are compensated. Also an extended Kalman filer (EKF) is utilized for attitude estimation. To accomplish the target tracking task, a path planning algorithm is designed under the constraints of quadrotor dynamics, and consecutive waypoint setpoints are generated. Then lower-level cascaded PID controllers are adopted to track the command waypoint. Finally, simulation and experimental results show the effectiveness and feasibility of the proposed methods.
|
|
| 6. |
- Li, Y., et al.
(författare)
-
Control algorithm design for tracking and interacting with a ground moving target using an aerial vehicle
- 2016
-
Ingår i: Proceedings of the 35th Chinese Control Conference 2016. - : IEEE Computer Society. - 9789881563910 ; , s. 5726-5731
-
Konferensbidrag (refereegranskat)abstract
- In this paper, a three-dimensional control problem is investigated in which an aerial vehicle equipped with a vision system is required to track and interact with a ground moving target. In order to guarantee the continuity of target observation, horizontal and vertical commands are designed separately under the constraints of the detection zone and vehicle dynamics. In order to realize a time-optimal trajectory as well as a smooth interaction with the target, a switched interaction algorithm is proposed, which combines an improved Rendezvous-Guidance (RG) algorithm and a Proportional Integral (PI) controller by the choice of a switching point. Moreover, simulation results are provided to demonstrate not only the effectiveness of the proposed algorithm, but also a high tolerance for detection and execution errors near the interaction point.
|
|
| 7. |
- Sun, Xiaoming, et al.
(författare)
-
Adjustable hardness of hydrogel for promoting vascularization and maintaining sternness of stem cells in skin flap regeneration
- 2018
-
Ingår i: Applied Materials Today. - : Elsevier. - 2352-9407. ; 13, s. 54-63
-
Tidskriftsartikel (refereegranskat)abstract
- The matrix mechanical stiffness of biomaterials plays an important role in the pluripotency and biological function of stem cells in the microenvironment. It is a key step to adjust the stiffness of biomaterials for inducing stem cells to promote vascularization in order to promote damaged tissue repair. In this study, we transplant adipose derived stem cells (ADSCs) within an in situ forming dextran hydrogel with controllable mechanical strength formed by cross-linking glycidyl methacrylate derivatized dextran and dithiothreitol, which can regulate the stemness and biological functions of stem cells. We show that softer dextran hydrogel can better maintain stemness markers expression of ADSCs, and significantly stimulate ADSCs to secrete angiogenic factors. The ADSCs-encapsulated hydrogel distinctly promote the skin flap survival compared to direct cell injection. Bioluminescence imaging analysis shows that in situ forming dextran hydrogel can improve cells retention, and postmortem analysis reveals that the transplanted ADSCs with hydrogel can promote vascularization. These results support the use of injectable dextran hydrogel for skin ischemia tissue regeneration. (C) 2018 Elsevier Ltd. All rights reserved.
|
|
| 8. |
- Wang, Kun, et al.
(författare)
-
Distributed Energy Management for Vehicle-to-Grid Networks
- 2017
-
Ingår i: IEEE Network. - Piscataway, NJ : IEEE. - 0890-8044 .- 1558-156X. ; 31:2, s. 22-28
-
Tidskriftsartikel (refereegranskat)abstract
- Making full use of V2G services, EVs with batteries may assist the smart grid in alleviating peaks of energy consumption. Aiming to develop a systematic understanding of the interplay between smart grid and EVs, an architecture for the V2G networks with the EV aggregator is designed to maintain the balance between energy suppliers (the grid side) and consumers (the EV side). We propose a combined control and communication approach considering distributed features and vehicle preferences in order to ensure efficient energy transfer. In our model, the integrated communication and control unit can achieve realtime and intelligent management with the logic controller and collected data. On the consumers' side, we theoretically analyze how to satisfy the charging constraints that we incorporate in the form of willingness to pay, and propose a distributed framework to coordinate the energy delivery behaviors for satisfying service demands. Moreover, illustrative results indicate that the proposed approach can yield higher revenue than the conventional pricing mechanism in V2G networks.
|
|
| 9. |
- Wang, Sifan, et al.
(författare)
-
Fire carbon emissions over Equatorial Asia reduced by shortened dry seasons
- 2023
-
Ingår i: npj Climate and Atmospheric Science. - 2397-3722. ; 6:1
-
Tidskriftsartikel (refereegranskat)abstract
- Fire carbon emissions over Equatorial Asia (EQAS) play a critical role in the global carbon cycle. Most regional fire emissions (89.0%) occur in the dry season, but how changes in the dry-season length affect the fire emissions remains poorly understood. Here we show that, the length of the EQAS dry season has decreased significantly during 1979–2021, and the delayed dry season onset (5.4 ± 1.6 (± one standard error) days decade−1) due to increased precipitation (36.4 ± 9.1 mm decade−1) in the early dry season is the main reason. The dry season length is strongly correlated with the length of the fire season. Increased precipitation during the early dry season led to a significant reduction (May: −0.7 ± 0.4 Tg C decade−1; August: −12.9 ± 6.7 Tg C decade−1) in fire carbon emissions during the early and peak fire season. Climate models from the Coupled Model Intercomparison Project Phase 6 project a continued decline in future dry season length in EQAS under medium and high-emission scenarios, implying further reductions in fire carbon emissions.
|
|
| 10. |
- Yang, B., et al.
(författare)
-
Detecting community structure in networks via consensus dynamics and spatial transformation
- 2017
-
Ingår i: Physica A. - : Elsevier. - 0378-4371 .- 1873-2119. ; 483, s. 156-170
-
Tidskriftsartikel (refereegranskat)abstract
- We present a novel clustering algorithm for community detection, based on the dynamics towards consensus and spatial transformation. The community detection problem is translated to a clustering problem in the N-dimensional Euclidean space by three stages: (1) the dynamics running on a network is emulated to a procedure of gas diffusion in a finite space; (2) the pressure distribution vectors are used to describe the influence that each node exerts on the whole network; (3) the similarity measures between two nodes are quantified in the N-dimensional Euclidean space by k-Nearest Neighbors method. After such steps, we could merge clusters according to their similarity distances and show the community structure of a network by a hierarchical clustering tree. Tests on several benchmark networks are presented and the results show the effectiveness and reliability of our algorithm.
|
|
