Restraint Function Research Articles

A Lie-bracket-based notion of stabilizing feedback in optimal control

For a control system two major objectives can be considered: the stabilizability with respect to a given target, and the minimization of an integral functional (while the trajectories reach this target). Here we consider a problem where stabilizability or controllability are investigated together with the further aim of a ‘cost regulation’, namely a state-dependent upper bound of the functional. This paper is devoted to a crucial step in the programme of establishing a chain of equivalences among degree-k stabilizability with regulated cost, asymptotic controllability with regulated cost and the existence of a degree-k Minimum Restraint Function (which is a special kind of Control Lyapunov Function). Besides the presence of a cost we allow the stabilizing ‘feedback’ to give rise to directions that range in the union of original directions and the family of iterated Lie bracket of length ≤ k . In the main result asymptotic controllability [resp. with regulated cost] is proved to be necessary for degree-k stabilizability [resp. with regulated cost]. Further steps of the above-mentioned logical chain as, for instance, a Lyapunov-type inverse theorem – i.e. the possibility of deriving existence of a Minimum Restraint Function from stabilizability – are proved in companion papers.

Can green bond issuance promote enterprise green technological innovation?

Green innovation is encouraged and green development is made possible with the help of green financial support. Green bonds, an essential component of green finance, are crucial for assisting businesses in pursuing green technological innovation (GTI). The 4107 businesses listed on the Shanghai and Shenzhen Stock Exchanges provided the research data for this article. This paper uses the propensity score matching and multi-time point Difference-in-Differences (PSM-DID) method to empirically investigate both the impact of green bond issuance on enterprise GTI and how it does so; in other words, its mechanism. According to statistics, green bond issuance can greatly increase enterprise GTI, and the outcome holds up to a number of robustness tests. In addition, heterogeneity analysis reveals that this promotion effect is more significant in large-scale, non-state-owned, and low-polluting businesses. Furthermore, mechanism tests show that green bond issuance can promote enterprise GTI through a financing restraint function, an investment incentive function and a green regulation function.

HJ Inequalities Involving Lie Brackets and Feedback Stabilizability with Cost Regulation

With reference to an optimal control problem where the state has to approach asymptotically a closed target while paying a non-negative integral cost, we propose a generalization of the classical dissipative relation that defines a Control Lyapunov Function to a weaker differential inequality. The latter involves both the cost and the iterated Lie brackets of the vector fields in the dynamics up to a certain degree kge 1, and we call any of its (suitably defined) solutions a degree-kMinimum Restraint Function. We prove that the existence of a degree-k Minimum Restraint Function allows us to build a Lie-bracket-based feedback which sample stabilizes the system to the target while regulating (i.e., uniformly bounding) the cost.

Design of Hardware Setup Based on IEC 61850 Communication Protocol for Detection & Blocking of Harmonics in Power Transformer

In this paper, the authors have developed a hardware model for blocking even and odd harmonics of a power transformer. In the proposed hardware model, intelligent differential & over-current relays are used for the blocking of harmonics of a power transformer. The harmonic restraint function on the differential relay (7UT61) prevents the relay from tripping during transformer magnetizing inrush current. However, the over-current relays which are used for back up protection does not have a harmonic restraint element, and over-current relay trips due to magnetizing inrush current, causes unwanted interruptions and power failures. The establishment of harmonic blocking scheme for over-current protection in power transformers is an important finding of this research study. IEC61850 standard-Based GOOSE (Generic Object Oriented Substation Event) applications used in power transformer protection for fast detecting and clearing of faults is an interested study presented in the proposed work.

Experimental and numerical analysis of mechanical properties of geocell reinforced reclaimed construction waste composite base layer

Geocell, as a high strength three-dimensional structure, has strong spatial lateral restraint function. This study aims to propose the use of geocell reinforced (GR) reclaimed construction waste (RCW) composite base, and to solve the problems of low strength and being prone to cracking of recycled base caused by poor performance of brick. In this paper, cement stabilized RCW mixture (C-RM) and RCW lean concrete (R-LC) are selected. Through laboratory tests and large-scale plate load test, the mechanical property of single GR RCW specimen and bearing capacity of GR RCW composite base are evaluated. Furthermore, based on the experiments, the Finite Element Method (FEM) is used for the mechanical analysis of GR reclaimed base asphalt pavement (RBAP). Results indicate that geocell has obvious reinforcement effect on the RCW concrete, and the effect is closely related to the brick/concrete ratio and specimen diameter. The displacement of RCW composite base is reduced, the resilient modulus is improved and the stress diffusion effect is enhanced obviously. What’s more, the bearing capability of GR R-CL is higher than that of GR C-RM. Additionally, geocell can improve the mechanical response of RBAP, and the main influence range is within 0.5 m from wheel load center.

Inrush current detection enhancement for legacy overcurrent relays in north delta electric distribution company

The second harmonic restraint method is the most common technique used by relay manufacturers to discriminate between inrush and fault currents. Unfortunately, many relays in the Egyptian distribution networks are old versions digital overcurrent relays that don't contain the second harmonic restraint method. In developing countries like Egypt, replacing a large number of conventional relays at one time may not be possible due to difficult economic conditions. This paper proposes a novel inexpensive solution by incorporating an additional circuit with the old version over-current relays. The proposed circuit applies a second harmonic restraint function for detecting the inrush currents as in the modern digital relays. The modified overcurrent relay is applied to a test system picked from North Delta Electric Distribution Company (NDEDC) Network in Egypt. The results demonstrate the successful operation for the proposed circuit along with the overcurrent relay in normal operation, switching cases, permanent faults, and in case of faults during energization. Furthermore, the proposed circuits integrated with old version overcurrent relays are successfully tested and verified in the presence of grid-connected Distributed Generation (DG) for both switching and fault operation modes. Also, it provides a cost-effective solution for the old version digital overcurrent relay in NDEDC.

High order Lyapunov-like functions for optimal control

We consider an optimal control problem where the state has to approach asymptotically a closed target, while paying an integral cost with a non-negative Lagrangian l. We generalize the dissipative relation that usually defines a Control Lyapunov Function by introducing a weaker differential inequality, which involves both the Lagrangian l and higher order dynamics’ directions expressed in form of iterated Lie brackets up to a certain degree k. The existence of a solution U of the resulting extended relation turns out to be sufficient for a twofold goal: on the one hand, it ensures that the system is globally asymptotically controllable to the target, and, on the other hand, it implies that the value function associated to the minimization problem is bounded above by a U-dependent function. We call such a solution U a degree-k Minimum Restraint Function (k > 1). An example is provided where a smooth degree-1 Minimum Restraint Function fails to exist, while the distance from the target happens to be a C ∞ degree-2 Minimum Restraint Function.

DYNAMIC MODELING OF NONIDEAL SYSTEM BASED ON GAUSS'S PRINCIPLE

The Gauss's principle gives the rules to identify the real motion from the possible motion by finding the extreme value of the function, which can make the dynamic problem of the multi-body system not need to solve the differential (algebra) equation, but adopt the optimization method of solving the minimum value, therefore, how to define the appropriate Gaussian constraint function is the prerequisite for the realization of dynamic optimization method. For the ideal system, the effect of constraints on the system can be reflected by the constraint equation and so the Gaussian constraint can be expressed as a function of the particle acceleration of the system, then the dynamic problem of the system can be described as the constrained optimization problem with the objective function as the Gaussian constraint function and the optimization variable as the particle acceleration. When the non-ideal factors such as dry friction need to be taken into account in the system, the partial interaction can not be covered by the defined constraint equation and needs to be described by additional physical laws. This sort of interaction destroys the extreme value characteristics of the original Gaussian restraint function of the system. Based on Gauss's principle of the variable classification, the extreme value principle of non-ideal system is derived and proved, whose objective function is expressed by ideal constraint forces. The Gauss's principle for non-ideal system in the existing literature is discussed and it is pointed out that it is an expression of the extreme value principle given when there is no obvious function correlation between the non-ideal constraint force and the ideal constraint force. But when they have obvious function relation (such as the linear relationship between the sliding friction force and the normal constraint force in the Coulomb friction law), this form will fail. And according to the extreme value principle given, the dynamic optimization model of contact problem for multi-body system considering friction is obtained. In the examples, the optimization model and the corresponding linear complementary model are analyzed, which is found that the two are necessary and sufficient conditions for each other under the condition of satisfying the uniqueness of rigid body sliding problem, thus, the reliability of the optimization model given is proved. And the dynamic simulation is carried out by the optimization calculation method. The simulation results show the feasibility and effectiveness of combining Gaussian principle with optimization algorithm.

Stabilizability in optimal control

We extend the classical concepts of sampling and Euler solutions for control systems associated to discontinuous feedbacks by considering also the corresponding costs. In particular, we introduce the notions of Sample and Euler stabilizability to a closed target set mathbf{C}with({p_{0}},W)-regulated cost, for some continuous, state-dependent function W and some constant {p_{0}}>0: it roughly means that we require the existence of a stabilizing feedback K such that all the corresponding sampling and Euler solutions starting from a point z have suitably defined finite costs, bounded above by W(z)/{p_{0}}. Then, we show how the existence of a special, semiconcave Control Lyapunov Function W, called {p_{0}}-Minimum Restraint Function, allows us to construct explicitly such a feedback K. When dynamics and Lagrangian are Lipschitz continuous in the state variable, we prove that K as above can be still obtained if there exists a {p_{0}}-Minimum Restraint Function which is merely Lipschitz continuous. An example on the stabilizability with ({p_{0}},W)-regulated cost of the nonholonomic integrator control system associated to any cost with bounded Lagrangian illustrates the results.

IEC61850 standard-based harmonic blocking scheme for power transformers

Transformer Differential and overcurrent schemes are traditionally used as main and backup protection respectively. The differential protection relay (SEL487E) has dedicated harmonic restraint function which blocks the relay tripping during the transformer magnetizing inrush conditions. However, the backup overcurrent relay (SEL751A) applied to the transformer protection does not have harmonic restraint element and trip the overcurrent relay during the inrush conditions. Therefore, major contribution of this research work is the developed harmonic blocking scheme for transformer which uses element (87HB) of the transformer differential relay (SEL487E) to send an IEC61850 GOOSE-based harmonic blocking signal to the backup overcurrent relay (SEL751A) to inhibit from tripping during the transformer magnetizing inrush current conditions. The simulation results proved that IEC61850 standard-based protection scheme is faster than the hardwired signals. Therefore, the speed and reliability of the transformer scheme are improved using the IEC61850 standard-based GOOSE applications.

Introduction of a bounded penalty function in contact-assisted simulations of protein structures to omit false restraints.

Contact-assisted simulations, the contacts being predicted or determined experimentally, have become very important in the determination of the structures of proteins and other biological macromolecules. In this work, the effect of contact-distance restraints on the simulated structures was investigated with the use of multiplexed replica exchange simulations with the coarse-grained UNRES force field. A modified bounded flat-bottom restraint function that does not generate a gradient when a restraint cannot be satisfied was implemented. Calculations were run with (i) a set of four small proteins, with contact restraints derived from experimental structures, and (ii) selected CASP11 and CASP12 targets, with restraints as used at prediction time. The bounded penalty function largely omitted false contacts, which were usually inconsistent. It was found that at least 20% of correct contacts must be present in the restraint set to improve model quality with respect to unrestrained simulations. © 2019 Wiley Periodicals, Inc.

The Role of Inhibition in Age-related Off-Topic Verbosity: Not Access but Deletion and Restraint Functions.

The speech of older adults is commonly described as verbose and off-topic, which is thought to influence their social communication. This study investigated the role of inhibition in age-related off-topic verbosity (OTV). Inhibition consists of three functions: access, deletion, and restraint. The access function is responsible for preventing irrelevant information from accessing the attention center (pre-mechanism of inhibition); The deletion function is responsible for deleting previously relevant but currently irrelevant information from working memory, and the restraint function is responsible for restraining strong but inappropriate responses (post-mechanisms of inhibition). A referential communication task was used to determine whether OTV was influenced by the pre-mechanism of inhibition. A self-involved event interview task was used to investigate the effect of the post-mechanisms of inhibition on OTV. Results showed that the OTV of the elderly participants was associated with an age-related decline in the post-mechanisms of inhibition, while the OTV exhibited by young adults was most likely due to deficits in the pre-mechanism function of inhibition. This research contributed to fill gaps in the existing knowledge about the potential relationship between specific functions of inhibition and age-related OTV.

Examination for Experimental Verification of Improvement of Power Quality in Distribution System by PCS

In the future, the power quality will decrease by the introduction of a lot of renewable energy sources. The topic of this research is a new method of operation of PCS (power conditioning systems) in the future distribution system. The purpose of this research is development of PCS with a function of improvement of the distribution system. Therefore, the authors propose a method of the power quality improvement of the distribution system by PCS. In addition, the authors construct the control logic to use in PCS. The control logic suggests adding harmonic restraint function to conventional control. These were verified by simulation and an experiment. As the results, we confirmed that basic operation of PCS being carried out, harmonics were restrained, and power quality had improved.

Test Study on Mechanical Characteristic of High Strength Composite Shaft Lining of Steel and Concrete

For the economic and reasonable application of high strength composite shaft lining of steel and concrete, the mechanical characteristic of this kind of structure were studied. First of all, according to the similarity theory, the shaft lining model is designed, then making the specimen and the loading test are put into effect. The results show that the combined action of inner and outer steel tube and middle concrete improves their respective performance. In shaft lining structure the stability of steel tube would be enhanced and the brittleness of high strength concrete would be improved also, so shaft lining structure shows fairly plastic feature when it is destroyed. Moreover, because of the restraint function of double-layer plate, the concrete in shaft lining structure completely is in triaxial compression stress state, the compressive strength can improve 1.53 ~ 1.90 times more than the concrete under uniaxial compression. The bearing capacity of shaft lining also increased greatly. Therefore, it is proposed that the improvement coefficient of the concrete’s compressive strength should be considered in the strength calculation of high composite shaft lining structure of steel and concrete.

Inhibition des réponses automatiques au test du Hayling dans la schizophrénie

In schizophrenia, alteration in the prefrontal cortex can induce some deficiencies of the executive functions, and among them errors in inhibition of prepotent responses. This type of inhibitory processes was called "restraint function" by Hasher et al. It implies a conscious and voluntary inhibition which demands attentional resources. Among the tasks exploring this function, the Hayling completion sentence task (Burgess and Shallice) appears to be the most specific. Moreover, healthy subjects performing this task in functional magnetic resonance imaging (fMRI) show activation of the prefrontal cortex. In this study, we investigated inhibitory processes in schizophrenic patients using two versions of the Hayling completion sentence task, a behavioural version and an fMRI version in order to assess both performance levels and brain correlates of inhibitory processes. Forty-eight schizophrenic participants according to DSM-IV, (mean age: 32.8, S.D. 7.7), stabilized for at least one month, receiving antipsychotic medication and with IQ higher than 70 (mean: 96.86, S.D. 20.67) and education level (mean: 11.15, S.D. 3.26) participated in the behavioural study. They were matched on age (mean: 33.8, S.D. 7.6) and education level (mean: 12.28, S.D. 2.87) with thirty-two healthy controls. Nineteen of schizophrenic participants (mean age: 33, S.D. 6.9 and IQ: 99, S.D. 10.74) were assessed by an fMRI adaptation of the Hayling task, matched with 12 controls (mean: 33.9, S.D. 7.3). All the participants had to perform the Hayling task and a speed accuracy task. The Hayling task consists in sentences for which the last word is missing. In the initiation condition, the participants had to complete the sentence with the appropriate word, whereas in inhibition condition the participants had to complete the sentence with inappropriate and unrelated words. Compared to controls, schizophrenics showed an increased number of errors in the inhibition of prepotent responses associated with increased reaction times, even when considering information processing speed. fMRI results showed fairly similar frontal activations in both groups. Nevertheless, schizophrenic patients presented principally large activations in dorsolateral and ventrolateral frontal cortex, the superior frontal sulcus, the frontal pole and the premotor cortex, and stronger activations (bilateral) in the posterior parietal cortex. Control subjects demonstrated a network of deactivated brain regions whereas the schizophrenics did not. Our results are in favour of poorer efficacy of restraint function, sometimes comprising impairment of inhibitory processes inducing errors in schizophrenics. This deficiency might be considered as insufficiency in attentional resources and/or in working memory. Hence patients cannot simultaneously restrain prepotent response and find appropriate controlled strategy for correct completion of the task. Moreover, bilateral patterns of parietal hyperactivation and absence of patterns of deactivation seem also in favour of an attentional hypothesis. The Hayling task might be interesting for assessment of inhibitory processes in schizophrenia.

Are There Uniform Age-Related Changes Across Tasks Involving Inhibitory Control Through Access, Deletion, and Restraint Functions? A Preliminary Investigation

According to Hasher, Zacks, and May (Attention and performance XVII. Cognitive regulation of performance: Interaction of theory and application, pp. 653–675, MIT Press, 1999), a general age-related decline of inhibitory control affects the contents of working memory through three kinds of functions: limiting access to irrelevant information, deleting information that is no longer relevant, and restraining the production of dominant responses. Supportive evidence has been found in a wide variety of experimental tasks. In the present study, age-related changes were examined in the same group of 34 older (aged 60 to 82) and 30 younger (aged 19 to 30) adults performing the same set of tasks involving the access, deletion, or restraint function. The results indicate that age-related declines in inhibition are not uniform but vary depending on task-specific characteristics.

Assessing automobile head restraint positioning in Portland, Oregon

Objective: Automobile head restraints, when used properly, have been shown to decrease the incidence and severity of whiplash injuries to the neck. Before the development of a public campaign on...

Development of Pinch Rolls to Control Strip Wandering in Strip Processing Lines.

In strip processing lines, it is important to restrain strip wandering which obstructs operational reliability and makes productivity decline. To improve the stability of the strip conveyance at the existing facilities in addition to the new facilities, a compact guiding apparatus was able to be introduced easily and was valid. In this report, the structure of the unique bent roll covered with a rubber sleeve, which has a wandering restraint function, was examined and the effect was clarified using an experimental apparatus. A rubber sleeve that needs durability to endure expansion and contraction by rotation of the bent roll was also examined. Production machine size rolls were newly developed and evaluated as pinch rolls in processing lines. Under the general condition to set pinch forces identically on both sides of the roll, this roll always has the ability to restrain strip wandering. When putting deviation of pinch forces on both sides, the ability of the wandering correction was increased. It was proposed that the wandering correction system, which controls the pinch force using the output of width sensor, was useful in the processing line. It was also possible to use these pinch rolls as the wandering correction apparatus at the place where it is difficult to use a general guiding apparatus because there is no restriction of line tension.

Restrained electrostatic potential atomic partial charges for condensed-phase simulations of carbohydrates

Charges derived from fitting a classical Coulomb model to quantum mechanical molecular electrostatic potentials (so called ESP-charges) are frequently used in simulations of macromolecules. Simulational methods that use ESP-charges generally reproduce the geometries of hydrogen bonded complexes, despite the fact that these charges are known to overestimate the strengths of these interactions. Through the use of a restraint function during the fitting of the partial charges to the electrostatic potentials the magnitudes of the charges may be attenuated (so called RESP-charges). For the AMBER force field RESP-charges have been proposed for proteins and nucleic acids. Here we examine a novel approach for determining the RESP-charges for carbohydrates based on molecular dynamics (MD) simulations of crystal structures. During a simulation, the crystallographic unit cell geometry is sensitive to both inter-molecular non-bonded forces and internal torsional rotations. However, for polar molecules, and specifically carbohydrates, the crystal geometries are particularly sensitive to the set of partial atomic charges employed in the simulation. Thus, given a force field in which the van der Waals and torsion terms are well parameterized, it is possible to assess the suitability of a set of partial charges by monitoring the properties of the crystal during an MD simulation. We have examined several charge sets for use with the GLYCAM parameters for carbohydrate and glycoprotein simulations and found that a restraint weight of 0.01 gives the best agreement with the neutron diffraction structure of α- d-glucopyranose. Unrestrained ESP-charges performed poorly as did the charges obtained from Mulliken and distributed multipole analyses of the quantum mechanical HF/6-31G ∗ wavefunctions.

A Nanosecond Molecular Dynamics Trajectory for a B DNA Double Helix: Evidence for Substates

We report here the results of the three molecular dynamics (MD) simulations on the d(CGCGAATTCGCG) duplex, two for 500 ps and one extended to 1 ns, as a response to serious questions about the sensitivity of the results to trajectory length and choice of starting structure. In 1992 we reported a 140-ps MD on the d(CGCGAATTCGCG) duplex including water and counterions. This simulation utilized the GROMOS force field,2 and irreversible base pair opening events were observed, as with other force field^.^.^ A second simulation employed a harmonic restraint function with GROMOS to assure that Watson-Crick base pairing was maintained intact. The results in the latter case were found to be consistent with available experimental data in comparison both with crystal structure datal and with 2D-NOESY buildup curves obtained from NMR spectro~copy.~~~ Subsequent studies of hydrogen bond interaction energies in Watson-Crick base pairs revealed that GROMOS underestimates these interactions. When a hydrogen bond potential7 was added, the energies compared closely with corresponding experimental data and ab initio quantum mechanical calculations.* The simulations described herein are based on GROMOS with this modification. The current studies also utilize a longer range switching function, which feathers the truncation of potentials over the length scale from 7.5 to 11.5 A and eliminates the tendency of charged groups to cluster at the cutoff limit when potentials are truncated too abr~ptly.~ We treat the effect of counterions implicity, using a reduced charge of -0.24 eu on the phosphate groups.IO All current simulations are carried out using free MD on the dodecamer duplex surrounded by - 3500 water molecules in a hexagonal prism elementary cell of constant volume, treated under periodic boundary conditions to model dilute aqueous (1) Swaminathan, S.; Ravishanker, G.; Beveridge, D. L. J. Am. Chem. Soc. 1991, 113,5027.