| 1. |
- Amos, Christopher I, et al.
(författare)
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Genome-wide association study identifies novel loci predisposing to cutaneous melanoma
- 2011
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 20:24, s. 23-5012
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Tidskriftsartikel (refereegranskat)abstract
- We performed a multistage genome-wide association study of melanoma. In a discovery cohort of 1804 melanoma cases and 1026 controls, we identified loci at chromosomes 15q13.1 (HERC2/OCA2 region) and 16q24.3 (MC1R) regions that reached genome-wide significance within this study and also found strong evidence for genetic effects on susceptibility to melanoma from markers on chromosome 9p21.3 in the p16/ARF region and on chromosome 1q21.3 (ARNT/LASS2/ANXA9 region). The most significant single-nucleotide polymorphisms (SNPs) in the 15q13.1 locus (rs1129038 and rs12913832) lie within a genomic region that has profound effects on eye and skin color; notably, 50% of variability in eye color is associated with variation in the SNP rs12913832. Because eye and skin colors vary across European populations, we further evaluated the associations of the significant SNPs after carefully adjusting for European substructure. We also evaluated the top 10 most significant SNPs by using data from three other genome-wide scans. Additional in silico data provided replication of the findings from the most significant region on chromosome 1q21.3 rs7412746 (P = 6 × 10(-10)). Together, these data identified several candidate genes for additional studies to identify causal variants predisposing to increased risk for developing melanoma.
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| 2. |
- Li, Yuling, et al.
(författare)
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Acceleration Feedback Control for Nonlinear Teleoperation Systems with Time Delays
- 2015
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Ingår i: International Journal of Control. - : Informa UK Limited. - 0020-7179 .- 1366-5820. ; 88:3, s. 507-516
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Tidskriftsartikel (refereegranskat)abstract
- A procedure for acceleration feedback control of the delayed nonlinear teleoperation system is proposed. The acceleration feedback is applied to the master controller, while in the slave side the position error plus nonlinear damping controller is used to guarantee the input-to-state stability (ISS) of the controlled system. The Lyapunov-Krasovskii methodology is applied to analyse the ISS of the closed-loop system, and hence the passivity assumption for human operators and the environment is not required. The stability criterion is formulated in the form of linear matrix inequalities. The behaviour of the resulting teleoperation system is illustrated in simulations, while the simulation results show that the acceleration feedback controller not only preserves good position tracking performance but also eludes contact instability.
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| 3. |
- Li, Yuling, et al.
(författare)
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Bilateral Teleoperation of Multiple Robots under Scheduling Communication
- 2020
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Ingår i: IEEE Transactions on Control Systems Technology. - 1063-6536. ; 28:5, s. 1770-1784
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, bilateral teleoperation of multiple slaves coupled to a single master under scheduling communication is investigated. The sampled-data transmission between the master and the multiple slaves is fulfilled over a delayed communication network, and at each sampling instant, only one slave is allowed to transmit its current information to the master side according to some scheduling protocols. To achieve the master-slave synchronization, round-robin (RR) scheduling protocol and try-once-discard (TOD) scheduling protocol are employed, respectively. By designing a scheduling-communication-based controller, some sufficient stability criteria related to the controller gain matrices, sampling intervals, and communication delays are obtained for the closed-loop teleoperation system under the RR and TOD scheduling protocols, respectively. Finally, simulation studies are given to validate the effectiveness of the proposed results.
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| 4. |
- Li, Yuling, et al.
(författare)
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Composite Adaptive Control for Bilateral Teleoperation Systems without Persistency of Excitation
- 2020
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Ingår i: Journal of the Franklin Institute. - : Elsevier BV. - 0016-0032. ; 357:2, s. 773-795
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Tidskriftsartikel (refereegranskat)abstract
- Composite adaptive control schemes, which use both the system tracking error and the prediction error to drive the updating law, have become widespread in achieving an improvement of system performance. However, a strong persistent-excitation (PE) condition is required to guarantee the convergence of the parameter estimation errors. This paper proposes a novel composite adaptive control for nonlinear teleoperation systems with dynamic uncertainties and time-varying communication delays, by which the parameter convergence is achieved without the PE condition. The novelty lies in the construction of the prediction errors by designing lower-bounded gain matrices of the prediction errors. The stability criteria of the closed-loop teleoperation system are given in terms of linear matrix inequalities. Simulation studies are given to show the effectiveness of the proposed method.
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| 5. |
- Li, Yuling, et al.
(författare)
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Distributed Neural-Network-Based Cooperation Control for Teleoperation of Multiple Mobile Manipulators Under Round-Robin Protocol
- 2021
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Ingår i: IEEE Transactions on Neural Networks and Learning Systems. - 2162-237X.
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Tidskriftsartikel (refereegranskat)abstract
- This article addresses the distributed cooperative control design for a class of sampled-data teleoperation systems with multiple slave mobile manipulators grasping an object in the presence of communication bandwidth limitation and time delays. Discrete-time information transmission with time-varying delays is assumed, and the Round-Robin (RR) scheduling protocol is used to regulate the data transmission from the multiple slaves to the master. The control task is to guarantee the task-space position synchronization between the master and the grasped object with the mobile bases in a fixed formation. A fully distributed control strategy including neural-network-based task-space synchronization controllers and neural-network-based null-space formation controllers is proposed, where the radial basis function (RBF) neural networks with adaptive estimation of approximation errors are used to compensate the dynamical uncertainties. The stability and the synchronization/formation features of the single-master-multiple-slaves (SMMS) teleoperation system are analyzed, and the relationship among the control parameters, the upper bound of the time delays, and the maximum allowable sampling interval is established. Experiments are implemented to validate the effectiveness of the proposed control algorithm.
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| 6. |
- Li, Yuling, et al.
(författare)
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Guaranteed Cost Control Design for Delayed Teleoperation Systems
- 2015
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Ingår i: Journal of the Franklin Institute. - : Elsevier BV. - 0016-0032. ; 352:11, s. 5085-5105
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Tidskriftsartikel (refereegranskat)abstract
- A procedure for guaranteed cost control design of delayed linear bilateral teleoperation systems with nonlinear external forces is proposed. The assumption that the external forces are nonlinear functions of velocities and/or positions of local devices, and one part of these forces satisfies a sector condition has been made. A virtual tool system is introduced to 'observe' the forces at the remote sides, the position and velocity information of the master, the slave and the virtual tool are feedbacked to the controllers, hence the proposed control scheme actually has a four-channel architecture. A delay-dependent stability criterion is formulated, and then a sub-optimal guaranteed cost controller is obtained by solving a convex optimization problem in the form of linear matrix inequalities (LMIs). The behavior of the resulting teleoperation system is illustrated in simulations. (C) 2015 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.
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| 7. |
- Li, Yuling, et al.
(författare)
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Neural-Network-Based Adaptive Control for Bilateral Teleoperation with Multiple Slaves under Round-Robin Scheduling Protocol
- 2021
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Ingår i: International Journal of Control. - : Informa UK Limited. - 0020-7179 .- 1366-5820. ; 94:6, s. 1461-1474
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Tidskriftsartikel (refereegranskat)abstract
- A neural-network-based adaptive control scheme is developed for bilateral teleoperation systems with single-master-multiple-slaves in the presence of dynamic uncertainties and communication constraint. Discrete-time data transmitting communication network with bandwidth limitation and time-varying communication delays is considered and the Round-Robin scheduling protocol is used to orchestrate the data transmission from multiple slaves to the master. Stability criteria of the closed-loop system are established by constructing appropriate Lyapunov-Krasovskii functionals. Simulation studies are performed to illustrate the effectiveness of the proposed control algorithm.
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| 8. |
- Ni, Jiun, et al.
(författare)
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Cystatin E is a novel human cysteine proteinase inhibitor with structural resemblance to family 2 cystatins
- 1997
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 272:16, s. 10853-10858
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Tidskriftsartikel (refereegranskat)abstract
- A new member of the human cystatin superfamily, called cystatin E, has been found by expressed sequence tag (EST) sequencing in amniotic cell and fetal skin epithelial cell cDNA libraries. The sequence of a full-length amniotic cell cDNA clone contained an open reading frame encoding a putative 28-residue signal peptide and a mature protein of 121 amino acids, including four cysteine residues and motifs of importance for the inhibitory activity of Family 2 cystatins like cystatin C. Recombinant cystatin E was produced in a baculovirus expression system and isolated. An antiserum against the recombinant protein could be used for affinity purification of cystatin E from human urine, as confirmed by N-terminal sequencing. The mature recombinant protein processed by insect cells started at amino acid 4 (cystatin C numbering), and displayed reversible inhibition of papain and cathepsin B (Ki values of 0.39 and 32 nM, respectively), in competition with substrate. Cystatin E is thus a functional cysteine proteinase inhibitor despite relatively low amino acid sequence similarities with human cystatins (26-34% identity with sequences for the Family 2 cystatins C, D, S, SN, and SA; <30% with the Family 1 cystatins, A and B, and domains 2 and 3 of the Family 3 cystatin, kininogen). Unlike other human low Mr cystatins, cystatin E is a glycoprotein, carrying an N-linked carbohydrate chain at position 108. Northern blot analysis revealed that the cystatin E gene is expressed in most human tissues, with the highest mRNA amounts found in uterus and liver. A strikingly high incidence of cystatin E clones in cDNA libraries from fetal skin epithelium and amniotic membrane cells (>0.5% of clones sequenced) indicates a protective role of cystatin E during fetal development.
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