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The work presented here proposes a novel strategy for characterizing the kinetics of a single robot as a team of agents working concurrently to satisfy a set of performance objectives. This approach enables the design and application of multi-agent control algorithms across robot subsystems in an effort to create control architectures that are inherently resilient to subsystem failure. A holonomic drive omnidirectional robot is analyzed using the proposed methodology. Each actuator subsystem is treated as an individual agent in a team that contributes to the robot’s coordinated motion. We generalize the approach for various classes of omnidirectional drive vehicles and demonstrate how to characterize the forces and moments associated with each subsystem. Validation is performed to demonstrate that the proposed approach yields robot motion models that are in agreement with those found by conventional rigid-body planar motion analysis.

The centromere is the chromosomal locus that ensures fidelity in genome transmission at cell division. Centromere protein A (CENP-A) is a histone H3 variant that specifies centromere location independently of DNA sequence. Conflicting evidence has emerged regarding the histone composition and stoichiometry of CENP-A nucleosomes. Here we show that the predominant form of the CENP-A particle at human centromeres is an octameric nucleosome. CENP-A nucleosomes are very highly phased on α-satellite 171-base-pair monomers at normal centromeres and also display strong positioning at neocentromeres. At either type of functional centromere, CENP-A nucleosomes exhibit similar DNA-wrapping behavior, as do octameric CENP-A nucleosomes reconstituted with recombinant components, having looser DNA termini than those on conventional nucleosomes containing canonical histone H3. Thus, the fundamental unit of the chromatin that epigenetically specifies centromere location in mammals is an octameric nucleosome with loose termini.

An actuator jam failure is mitigated using a servomechanism formulation where the failed control surface is modeled as an exogenous input to the degraded plant. The approach exploits switching control, linear output regulation, H2 control theory, and an outer-loop PI control algorithm to track a desired reference input. Application is demonstrated using the nonlinear NASA AirSTAR Generic Transport Model (GTM).

The centromere is the chromosomal locus that serves as the site of kinetochore formation and spindle microtubule attachment in mitosis. Centromere protein A (CENP-A) is a histone H3 variant that epigenetically specifies centromere location. Conflicting evidence has emerged regarding the histone composition and stoichiometry of CENP-A nucleosomes and the predominant form of the CENP-A nucleosome throughout the cell cycle remains controversial. Indeed, several recent reports propose that CENP-A predominantly exists in half-nucleosomes (i.e. ‘hemisomes'). We have developed novel genomic analysis tools that we marry to existing massively parallel paired-end, long-read DNA sequencing technology to probe CENP-A nucleosome structure at centromeres. using this approach in patient-derived cells harboring a neocentromere (a newly arisen functional centromere) we simultaneously identify the length and complete sequence reads of nucleosome positions at base pair resolution on normal repetitive centromere DNA and the unique sequences underlying neocentromeres. Unlike bulk nucleosomes from the same preparations that predominantly protect a single peak size (∼150 bp) from nuclease digestion, CENP-A nucleosomes occupy two major peak sizes (∼130 and ∼110 bp) and a minor peak (∼150 bp). Each peak is substantially longer than what could be protected by a hemisome or any other tetramer of histones (i.e. protection of ∼60-80 bp from nuclease digestion). Further, the prominent position on centromeric DNA of the 110 bp peak is internal to the most prominent position of the 130 bp peak, indicating a stable, protected nucleosome core with loose termini. Strikingly, pure, reconstituted octameric CENP-A nucleosomes yield similarly sized terminally digested DNA fragments under conditions where their canonical H3-containing counterparts protected ∼150 bp of nucleosomal DNA. Our findings indicate that the fundamental unit of functional centromeric chromatin is an octameric nucleosome with loose termini.

Many gun launched projectiles spin to maintain in-flight dynamic stability. This spinning often induces the gyroscopic phenomenon known as precession, or coning. Coning poses a problem for actively controlling the projectile. A control scheme is proposed that can compensate for the coning angle of the projectile and allow front-mounted canards to efficiently change the projectile flight path without reaching a stall condition. Closed-loop regulation and H 2 control theories are employed to construct the controller.