Optimality Conditions For Systems Research Articles

Daily singing of adult songbirds functions to maintain song performance independently of auditory feedback and age

Many songbirds learn to produce songs through vocal practice in early life and continue to sing daily throughout their lifetime. While it is well-known that adult songbirds sing as part of their mating rituals, the functions of singing behavior outside of reproductive contexts remain unclear. Here, we investigated this issue in adult male zebra finches by suppressing their daily singing for two weeks and examining the effects on song performance. We found that singing suppression decreased the pitch, amplitude, and duration of songs, and that those song features substantially recovered through subsequent free singing. These reversible song changes were not dependent on auditory feedback or the age of the birds, contrasting with the adult song plasticity that has been reported previously. These results demonstrate that adult song structure is not stable without daily singing, and suggest that adult songbirds maintain song performance by preventing song changes through physical act of daily singing throughout their life. Such daily singing likely functions as vocal training to maintain the song production system in optimal conditions for song performance in reproductive contexts, similar to how human singers and athletes practice daily to maintain their performance.

Optimality Conditions for Systems with Distributed Parameters Based on the Dubovitskii–Milyutin Theorem with Incomplete Information About the Initial Conditions

Optimality Conditions for Systems with Distributed Parameters Based on the Dubovitskii–Milyutin Theorem with Incomplete Information About the Initial Conditions

Some necessary optimality conditions for systems with fractional Caputo derivatives

In this paper, we consider an optimal control problem in which a dynamical system is controlled by a nonlinear Caputo fractional state equation. First, an analogue of the Pontryagin maximum principle is obtained, and in the case of the degeneration of the Pontryagin maximum principle, a high-order necessary optimality condition is obtained. Further, if the control under study lies inside the set of restrictions on the control, then we obtain an analogue of the Euler equation, an analogue of the Legendre-Clebsch condition, and when the Legendre-Clebsch condition degenerates, we obtain the necessary high-order optimality condition.

Reliability and maintenance analysis of coherent systems subject to aging and environmental shocks

In reliability engineering, each component of the system, in addition to internal failures, is usually subject to lethal external shocks. Usually, the random shocks are produced by a random environment, and modeled by a stochastic process. In this paper, using the theory of signature and survival signature depending on whether the components of the system are of one type or several types, a general approach in assessing the system reliability is presented. We also propose some preventive maintenance strategies for a multi-component system whose components are subject to both internal failures and fatal shocks. In each policy, based on the maintenance costs of the system and its components, a cost function is computed as a criterion to be optimized. The signature-based representation of the system reliability is especially useful to maintain the system in optimal conditions by considering the component repair costs. To illustrate the theoretical results, extensive graphical and numerical examples are presented.

A Novel Approach in Sorting Chirality Species of Single-Wall Carbon Nanotubes Based on an Aqueous Two-Phase System of Polymer-Salt

Sorting of distinct (n, m) chirality species of single-wall carbon nanotubes (SWCNTs) is essential for progress in technical applications in the field of electronic and optic devices. The purpose of this study is to investigate the isolation of single-wall carbon nanotubes based on diameters/chirality in a polymer-salt (polyethylene glycol and sodium citrate) aqueous two-phase system (ATPS) a substitute for common polymer-polymer (polyethylene glycol and dextran) system. The ATPS based on polymer-salt used instead of the common polymer-polymer system due to low viscosity, reduced surface tension, and lower cost of sodium citrate compared to the dextran. For this purpose, the ratio of concentrations of polyethylene glycol to sodium citrate as well as the effect of temperature on the isolation are both investigated and the selectivity and the recovery estimated approximately. The absorbance spectra from both top and bottom phases at different polymer and salt contents and at different temperatures show that by using this system in optimal conditions of polymer to salt ratio of 2:1 at temperature of 20 °C, a suitable separation of nanotubes with 85% yield of the chiral groups of 9 and 10 can be obtained.

Preparation of Degradable Oxidized Regenerated Cellulose Gauze by Zinc Modification on HNO3/Cu Oxidized Viscose Fibers

In the present research, the oxidized regenerated cellulose (ORC), type viscose, was obtained by selective oxidation system, HNO3-Cu. Oxidizing parameters- acid concentration, reaction time and Cu content- were optimized through the central composite design (CCD) to obtain high yield of carboxyl content. The optimum oxidation conditions were as follows: time 30 h, acid concentration 46 % and Cu content 2.5 (g), in which the carboxyl value was 16.02±0.25 %. Optimal oxidized regenerated cellulose was characterized using FTIR, XRD, TG/DTA, SEM and EDX. For the next stage, a zinc modified oxidized regenerated cellulose gauze (ORC-Zn) was prepared by oxidation of viscose with HNO3/Cu system in optimal conditions and, finally, ion modification with a ZnCl solution. In vitro sedimentation studies demonstrated that the ORC-Zn sample reduced the erythrocyte sedimentation rate (ESR) by 36 % as compared to the control, whereas the commercial ORC reduced ESR by 20 %. In addition, degradability and antibacterial properties of ORC-Zn gauze have been greatly improved compared to ORC one.

2-Factor Newton Method for Solving Constrained Optimization Problems with a Degenerate Kuhn–Tucker System

A new method is proposed for solving constrained optimization problems with inequality constraints in the case when the system of Kuhn–Tucker necessary optimality conditions is degenerate. This situation arises, for example, when the strict complementarity conditions do not hold for the solution. A reduction of the inequality-constraint problem to an equality-constraint one and the use of a new 2 factor Newton method for efficiently solving the resulting degenerate system of optimality conditions are justified.

A study of aging effects of barrel Time-Of-Flight system in the BESIII experiment

The Time-Of-Flight system consisting of plastic scintillation counters plays an important role for particle identification in the BESIII experiment at the BEPCII double ring e+e− collider. Degradation of the detection efficiency of the barrel TOF system has been observed since the start of physical data taking and this effect has triggered intensive and systematic studies about aging effects of the detector. The aging rates of the attenuation lengths and relative gains are obtained based on the data acquired in past several years. This study is essential for ensuring an extended operation of the barrel TOF system in optimal conditions.

Influence of abiotic factors on photosynthesis and production process of different winter wheat varieties

Aim. The investigation of photosynthesis and production process in winter wheat varieties, different in their grain productivity, its connection to the active surface area of the root system in optimal conditions, under drought and mineral nutrition defi ciency. Methods. Physiological, biochemical, gas exchange analysis, statisti- cal methods. Results. It was demonstrated that different conditions of mineral nutrition and soil drought have impact on the intensity of photosynthesis, photo- and dark respiration, the content of pigments in the fl ag leaf of winter wheat plants; the results obtained testify to the interrelation of these indices to the active surface area of the root system and grain productivity of winter wheat varieties, different in potential grain productivity. Conclusions. It was determined that under drought the photosynthetic apparatus of a highly productive winter wheat variety Smuhlianka demonstrated higher stability compared to the photosynthetic apparatus of the vari- ety Myronivska 808, moderately resistant to drought conditions. At the same time, highly intensive varieties of winter wheat, Favorytka and Smuhlianka, had a larger active surface area of the root system and chlorophyll content in leaves, compared to Myronivska 808 plants, notable for their lower grain productivity. It was deter- mined that there was considerable reliable correlation between the intensity of fl ag leaf photorespiration and the active surface area of the root system in winter wheat plants of varieties Myronivska 808 and Smuhlianka (r = 0.805). Considerable correlation (r = 0.878) was found between the intensity of fl ag leaf photorespiration in the heading-blossoming phase and the sum of chlorophylls in these leaves. It was determined that the index S r act × chlorophyll may be used to estimate the active surface area of the root system with the error of up to 3.8 % for fi ve winter wheat varieties.

Monitoring and assessment of an industrial antifouling treatment. Seasonal effects and influence of water velocity in an open once-through seawater cooling system

The fouling is one of the main problems affecting industrial heat exchangers using water from natural sources (lakes, rivers and sea) as the cooling agent. Negative consequences of the fouling formation are the reduction in heat transfer, loss of cooling efficiency, premature deterioration of facilities and increased operation and maintenance costs. In order to minimize this undesirable phenomenon and its effects, antifouling treatments are applied to reduce the accumulation of deposits. A major concern among industrial facilities is the correct choice of a suitable antifouling treatment and its optimization in order to keep the cooling system in optimal conditions and, at the same time, minimize harmful discharges to the environment. This study evaluates the development of fouling in a condenser of a combined cycle power plant, cooled by seawater under actual operating conditions, which means: irregular chlorine treatment, seasonal influence and fluctuation of flow rate according to the number of circulating pumps in operation. The aim of the study was to determine the best operating conditions for improving antifouling treatment. The experiments were carried out in a pilot plant simulating the industrial condenser and operating as side-stream monitoring device on the cooling system while drawing water from the same point than the power plant. Fouling progression throughout an annual cycle and under actual operating conditions was monitored and evaluated. In all the seasons, the chlorine-based antifouling treatment reduced the amount of total solids by approximately 80–85% compared to the control. Control tubes as well as the rest of the test tubes, presented the maximum accumulated fouling in spring, while the lowest quantity of fouling was obtained in winter. The results under the different operating conditions showed that both, the solids accumulation as well as the heat transfer resistance were higher than the rest, when low water velocities were used. Furthermore, the circulating water flow rate affected the composition of the deposits.

Policy-Based, Service Level–Oriented Route Guidance in Road Networks

The realization of traffic management on a network level is not only theoretically complex, but also practically challenging because the traffic management policy of the road authorities must be taken into account. In the Netherlands, this policy harmonizes the interests of involved stakeholders by means of a common vision on the functioning of the network, expressed in road priorities and the corresponding target service levels. As a result, network states that reflect the policy's objectives in a systematic and comprehensible way must be realized. This paper presents a predictive route guidance approach that is able to operationalize the formulated policy. This approach degrades and restores target service levels of routes according to their difference in priority, with respect to the network performance. The control approach consists of a finite state machine that determines target service levels according to predicted traffic conditions. These target service levels are used as setpoints in a feedback controller, and the result is a corresponding output signal of a variable message sign. By means of a test case, the finite state machine is compared with a model predictive route guidance controller (that realizes system optimal conditions) and with a user equilibrium feedback controller (that realizes user optimal conditions). Results showed that the finite state machine was able to prevent or limit the effects of phenomena that caused decreased network performance in a comprehensible and efficient way while also accounting for the interests of the road users.

Direct Verification of Parametric Solution for Vibration Reduction Control Problems

For the optimal control problems formulated with limited actuator authority, the optimal solution is given by Pontryagin's minimum principle that provides the necessary and sufficient conditions of optimality for systems that are normal. If the resulting solution is a switched control, an alternate computation methodology exists where the problem is formulated as a parametric optimization problem with the switching times as the variables. For vibration reduction problems with constrained endpoints, the parametric formulation is not convex and the Karush-Kuhn-Tucker conditions can only guarantee the local optimality of the solution. In this paper an approach is presented to verify the optimality of the parametric solution for optimal control problems with terminal state inequalities. The verification conditions are derived using the switching function, Karush-Kuhn-Tucker, and the transversality equations. The resulting problem is formulated as a linear program that provides a very efficient test of optimality. Example problems are given to demonstrate the application of this algorithm.

Studies on muonic dynamics of liquid D–T–H in dtμ muonic-molecule resonance formation and its comparison with a D–T system

Recent experimental and theoretical studies on muon-catalyzed fusion in a mixture of three gases, D–T–H, have shown that the muon-cycling-rate changes obtained are mostly in contradiction with each other and depend strongly on the physical conditions of the system. In this paper, we have considered the muon-cycling rate and its relevant nonlinear dynamical equations for mixtures of D–T and D–T–H in practical conditions where the muon-cycling rate is temperature; density of the mixture; and relative-particle concentration (deuterium, tritium, and hydrogen) dependent. Our theoretical method has shown that addition of protium to a D–T mixture leads to a significant decrease in the cycling rate, namely, by a factor of more than 15 in the liquid mixture and more than three in the gaseous mixture at 300–600 K. We show that the results obtained for given experimental conditions are in very good agreement with recent experimental values of Joint Institute for Nuclear Research in Dubna. The given reliable theoretical method leads us to determine the optimal condition of the muon-cycling rate such as relative-particle concentration in the resonance-temperature range at liquid hydrogen density, Φ = 1. It is shown that for a deuterium and tritium relative concentration of Cd = Ct = 0.45 with Cp = 0.1 and ωs = 0.0029, a muon-cycling rate of 199 in the dtμ branch at 800 K is achievable, which compared to the D–T system in optimal conditions, still has a 29% enhancement. Finally, by energy-gain evaluation of resonance-muon-catalyzed fusion, we show that even this key step in high-yield μCF is far, far away from sufficiently minimal values to be of interest for practical applications of such a system. PACS No.: 25.30M

Optimality conditions for systems driven by nonlinear evolution equations

Using the Dubovitskii‐Milyutin theory we derive necessary and sufficient conditions for optimality for a class of Lagrange optimal control problems monitored by a nonlinear evolution equation and involving initial and/or terminal constraints. An example of a parabolic control system is also included.

On necessary optimality conditions for systems governed by a two point boundary value problem. II

The present paper is a free continuation of [6] and deals with a control problem for a quasilinear second order ordinary differential equation with homogeneous Dirichlet boundary conditions. The control function occurs in all coefficients of the differential equation and its values are supposed to be elements of a given arbitrary set Q ⊂ R m Using needle-like variation of the optimal control and via a suitable representation of the related state a necessary Pontryagin like optimality condition is derived.

Optimality conditions for systems with insufficient data

In this paper we use the Dubovitski–Milyutin formalism to establish necessary and sufficient conditions for optimality in a nonlinear, distributed parameter control system, with convex cost criterion and initial condition not given a priori (that is it is not a known function but instead it belongs to a specified set). Our result extends a recent theorem of Lions. Finally a concrete example is worked out in detail.

On necessary optimality conditions for systems Governed by a two point boundary value problem. I

On necessary optimality conditions for systems Governed by a two point boundary value problem. I

The Hydrothermal Optimal Load Flow, A Practical Formulation and Solution Techniques Using Newton's Approach

This paper is concerned with the problem of optimal power flow in a hydro-thermal electric power system (HTOPF). The formulation and optimality conditions for systems with fixed head hydro-plants subject to an energy limited constraint are presented. The solution to obtain the optimal operational strategy is implemented using Newton's method. Due to the large scale nature of the problem, special sparsity oriented and structural property enhancements are explored and four versions for algorithmic implementation are detailed in the paper. Special attention is paid to finding realistic initial guess estimates for the algorithms reported. Results of computational experience with six standard test systems are reported in the paper.

Necessary optimality conditions for systems described by nonlinear elliptic equations. II (in Russian)

Necessary optimality conditions for systems described by nonlinear elliptic equations. II (in Russian)

Necessary optimality conditions for systems described by nonlinear elliptic equations. I (in Russian)

Necessary optimality conditions for systems described by nonlinear elliptic equations. I (in Russian)