Selection and Setting of an Intelligent Fuzzy Regulator based on Nonlinear Model Simulations of a Helicopter in Hover

Most research on fuzzy regulators has focused on the integrating rules in intelligent control systems. This paper evaluates a fuzzy helicopter regulator for a single-rotor PZL Kania helicopter. Unlike other models which only match stable flight ability, the model presented in this paper attempts to match the links between disturbances and hover conditions. Two simulations were performed to validate the model. In the first simulation, a helicopter was evaluated in a fixed hover position. In the second simulation, model robustness was validated by introducing wind gust. Results, both with the initial and with the modified model demonstrated the viability of the proposed regulator.

Topological sensitivity derivative and finite topology modifications: application to optimization of plates in bending

The concept of topological sensitivity derivative is introduced and applied to study the problem of optimal design of structures. It is assumed, that virtual topology variation is described by topological parameters. The topological derivative provides the gradients of objective functional and constraints with respect to these parameters. This derivative enables formulation of the conditions of topology transformation. In this paper formulas for the topological sensitivity derivative for bending plates are derived. Next, the topological derivative is used in the optimization process in order to formulate conditions of finite topology modifications and in order to localize positions of the modifications. In the case of plates they are related to introduction of holes and introduction of stiffeners. The theoretical considerations are illustrated by some numerical examples.     

Forward tracking of complex trajectories with non-Standard N-Trailers of non-minimum-phase kinematics avoiding a jackknife effect

It is a common conviction that forward motion control of tractor-trailer vehicles is a substantially simpler problem relative to reversing with trailers. This opinion may be misleading when considering the N-trailer vehicles moving forward with positive hitching offsets when a guidance point is located on a trailer. Due to the non-minimum-phase nature of vehicle kinematics, closing a feedback from a trailer posture can lead to the jackknife effect in this case. So far, there has been no solution to this problem for the N-trailers admitting trajectories of a varying curvature. To fill this gap, we propose a scalable and modular control strategy applicable to the N-trailer vehicles equipped solely with off-axle interconnections. The concept relies on a transformation of the control problem posed for the non-minimum-phase kinematics into a corresponding problem formulated for a virtual vehicle of minimum-phase kinematics, which can be solved by using the recently proposed cascade-like controller.     

Approximative piecewise constant bang-bang principle for differential repetitive processes

In the article, we consider a point controllability over all (infinite many) passes for linear differential repetitive processes. We prove the following approximative piecewise constant bang-bang principle: the set of points that can be reached with the aid of measurable controls on passes, taking the values in a convex compact set M ? ? ^r coincides with the closure of the set of points that can be reached with the aid of piecewise constant controls on passes, taking the values in the set of extreme points of M.     

Routing equal-size messages on a slotted ring

We deal with the problem of routing messages on a slotted ring network in this paper. We study the computational complexity and algorithms for this routing by means of the results known in the literature for the multi-slot just-in-time scheduling problem. We consider two criteria for the routing problem: makespan, or minimum routing time, and diagonal makespan. A?diagonal is simply a schedule of ring links i=0,??,q?1 in q consecutive time slots, respectively. The number of diagonals between the earliest and the latest diagonals with non-empty packets is referred to as the diagonal makespan. For the former, we show that the optimal routing of messages of size k, is NP-hard in the strong sense, while an optimal routing when k=q can be computed in O(n ²log² n) time. We also give an O(nlogn)-time constant factor approximation algorithm for unit size messages. For the latter, we prove that the optimal routing of messages of size k, where k divides the size of the ring q, is NP-hard in the strong sense even for any fixed k??1, while an optimal routing when k=q can be computed in O(nlogn) time. We also give an O(nlogn)-time approximation algorithm with an absolute error 2q?k.     

Noscapine Acts as a Protease Inhibitor of In Vitro Elastase-Induced Collagen Deposition in Equine Endometrium

Endometrosis is a reproductive pathology that is responsible for mare infertility. Our recent studies have focused on the involvement of neutrophil extracellular traps enzymes, such as elastase (ELA), in the development of equine endometrosis. Noscapine (NOSC) is an alkaloid derived from poppy opium with anticough, antistroke, anticancer, and antifibrotic properties. The present work investigates the putative inhibitory in vitro effect of NOSC on collagen type I alpha 2 chain (COL1A2) mRNA and COL1 protein relative abundance induced by ELA in endometrial explants of mares in the follicular or mid-luteal phases at 24 or 48 h of treatment. The COL1A2 mRNA was evaluated by qPCR and COL1 protein relative abundance by Western blot. In equine endometrial explants, ELA increased COL 1 expression, while NOSC inhibited it at both estrous cycle phases and treatment times. These findings contribute to the future development of new endometrosis treatment approaches. Noscapine could be a drug capable of preventing collagen synthesis in mare’s endometrium and facilitate the therapeutic approach.     

Performing work with asynchronous processors: Message-delay-sensitive bounds

This paper considers the problem of performing tasks in asynchronous distributed settings. This problem, called Do-All, has been substantially studied in synchronous models, but there is a dearth of efficient algorithms for asynchronous message-passing processors. Do-All can be trivially solved without any communication by an algorithm where each processor performs all tasks. Assuming p processors and t tasks, this requires work Θ (p · t). Thus, it is important to develop subquadratic solutions (when p and t are comparable) by trading computation for communication. Following the observation that it is not possible to obtain subquadratic work when the message delay d is substantial, e.g., d = Θ (t), this work pursues a message-delay-sensitive approach. Here, the upper bounds on work and communication are given as functions of p, t, and d, the upper bound on message delays, however, algorithms have no knowledge of d and they cannot rely on the existence of an upper bound on d. This paper presents two families of asynchronous algorithms achieving, for the first time, subquadratic work as long as d = o (t). The first family uses as its basis a shared-memory algorithm without having to emulate atomic registers assumed by that algorithm. These deterministic algorithms have work O (tp^ε + pdt/d^ε) for any ε > 0. The second family uses specific permutations of tasks, with certain combinatorial properties, to sequence the work of the processors. These randomized (deterministic) algorithms have expected (worst-case) work O (t log p + pd log (2 + t/d)). Another important contribution in this work is the first delay-sensitive lower bound for this problem that helps explain the behavior of our algorithms: any randomized (deterministic) algorithm has expected (worst-case) work of Ω (t + pd log_d+1t).     

Broadcasting Spanning Forests on a Multiple-Access Channel

The problem of finding a spanning forest of a graph in a distributed-processing environment is studied. If an input graph is weighted, then the goal is to find a minimum-weight spanning forest. The processors communicate by broadcasting. The output consists of the edges that make a spanning forest and have been broadcast on the network. Input edges are distributed among the processors, with each edge held by one processor. The underlying broadcast network is implemented as a multiple-access channel. If exactly one processor attempts to perform a broadcast, then the broadcast is successful. A message broadcast successfully is delivered to all the processors in one step. If more than one processors broadcast simultaneously, then the messages interfere with each other and no processor can receive any of them. Optimality of algorithmic solutions is investigated, by way of comparing deterministic with randomized algorithms, and adaptive with oblivious ones. Lower bounds are proved that either justify the optimality of specific algorithms or show that the optimal performance depends on a class of algorithms.     

Influence of iodination on tribological properties of acrylonitrile—butadiene rubber

Surface modification of acrylonitrile-butadiene copolymer (NBR) vulcanizates by treatment with an iodine solution results in a significant decrease in the coefficient of friction. The effect of modification is attributed to formation of a thin surface layer, incorporating iodine species, which has a higher modulus than the bulk material. The surface layer also has an increased roughness which, combined with the increased local stiffness, causes the reduction in friction. These factors overcome an observed increase in the surface energy after modification, which would act to increase the friction. NBR subjected to iodination kept its bulk elasticity, which plays an important part in the mechanism of deformation of the elastomer under conditions of friction, and ensures that the modified NBR retains its properties in engineering applications. The durability of the surface modification is attributed to interactions between iodine and nitrile groups from the acrylonitrile monomer units. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1927–1936, 1997     

Application of diol dimethacrylates in dental composites and their influence on polymerization shrinkage

Diol dimethacrylates (DD) that possess long aliphatic chains were incorporated into the conventional dental resin mixtures (e.g., BIS-GMA and TEGDMA) in order to reduce the polymerization stress and shrinkage of final copolymers. It was found that the polymerization shrinkage of the standard copolymer (60 mol % BIS-GMA and 40 mol % TEGDMA) could be reduced even by 20% when TEGDMA is substituted by a long aliphatic diol dimethacrylate. These phenomena can be attributed to the low miscibility of BIS-GMA and DD, which causes long aliphatic chains of DD to remain in coil form in a reaction mixture. The coils can be unwound and expand as a result of the formation of covalent bonds during polymerization and thus reduce the polymerization shrinkage. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 2333–2337, 1997