Cyclic Circuits Research Articles

Aromaticity and Magnetic Behavior in Benzenoids: Unraveling Ring Current Combinations.

Nowadays, an active research topic is the connection between Clar's rule, aromaticity, and magnetic properties of polycyclic benzenoid hydrocarbons. In the present work, we employ a meticulous magnetically induced current density analysis to define the net current flowing through any cyclic circuit, connecting it to aromaticity based on the ring current concept. Our investigation reveals that the analyzed polycyclic systems display a prominent global ring current, contrasting with subdued semi-local and local ring currents. These patterns align with Clar's aromatic π-sextets only in cases where migrating π-sextet structures are invoked. The results of this study will enrich our comprehension of aromaticity and magnetic behavior in such systems, offering significant insights into coexisting ring current circuits in these systems.

A Half Century Defining the Logic of Cellular Life.

Over more than fifty years, I have studied how the logic that controls and integrates cell function is built into the dynamic architecture of living cells. I worked with a succession of exceptionally talented students and postdocs, and we discovered that the bacterial cell is controlled by an integrated genetic circuit in which transcriptional and translational controls are interwoven with the three-dimensional deployment of key regulatory and morphological proteins. Caulobacter's interconnected genetic regulatory network includes logic that regulates sets of genes expressed at specific times in the cell cycle and mechanisms that synchronize the advancement of the core cyclical circuit with chromosome replication and cytokinesis. Here, I have traced my journey from New York City art student to Stanford developmental biologist.

MATHEMATICAL RISK ASSESSMENT MODEL FOR BIODIESEL PRODUCTION PROJECTS IN UKRAINE AGRICULTURE

Abstract. One of the trends in the development of the market of alternative motor fuels is the production and use of biofuels, biodiesel in particular. Biodiesel which is used by domestic farmers is mainly self-produced. The current situation is related, first of all, to the lack of a single standard (regulation) for biodiesel production technology and is not enshrined in any legal act in Ukraine. In the conditions of the market functioning, agricultural producers face various risk factors, in particular, instability of prices for fuels and lubricants, monopolization of certain regions or market segments by traders, low quality of fuel, etc. Conditions of biodiesel production, as well as other economic activities, usually require the creation or involvement of labor, financial and material resources, which also affects the change in the level of risk. These problems can be solved by adapting and improving the existing mathematical apparatus to risk assessment for biodiesel production projects by agricultural enterprises. The main legal act that allows to determine and assess the level of risk is the state standard of Ukraine «Risk Management. Methods of general risk assessment», which served as the methodological foundation of the study. We propose to use three main technological schemes of biodiesel production, namely: cyclic scheme of production with the use of catalysts; non-catalytic cyclic circuit and multi-reactor continuous circuit scheme. In order to analyze each of these schemes, it is proposed to analyze the feasibility of investment in terms of their effectiveness and tie-in to the risks of introducing innovative technologies. The developed methodology provides a substantiation for the choice of technological option for biodiesel production. An algorithm for calculating risks has been proposed for the introduction of biodiesel production, the preparation of business plans and the assessment of criticality of possible losses for the production. The use of methods of vector algebra and fuzzy logic in the formation of the mathematical model makes it possible to estimate the probability indicators of each risk. Keywords: biodiesel, risks, mathematical model, agriculture, risk assessment, risk assessment methods. JEL Classification C60, Q42 Formulas: 8; fig.: 0; tabl.: 0; bibl.: 18.

Modeling of stochastic brain function in artificial intelligence

Objectives -research of stochastic brain function in respect to creation of artificial intelligence. Material and methods. Mathematical modeling principles were used for simulation of brain functioning in a stochastic mode. Results. Two types of brain activity were considered: determinated type, usually modeled using the perceptron, and stochastic type. It is shown, that stochastic brain function modeling is the necessary condition for AI to become capable of creativity, generation of new knowledge. Mathematical modeling of a neural network of the cerebral cortex, consisting of the set of the cyclic neuronal circuits (memory units), was performed for the stochastic mode of brain functioning. Models of "two-dimensional" and "one-dimensional" brain were analyzed. The pattern of excitation in memory units was calculated in the "one-dimensional" brain model. Conclusion. Relying on the knowledge of the stochastic mode of brain function, a way of creation of AI can be offered. а-rhythm of a patient is a recommended focus of the therapist's attention in diagnostics and treatment of brain disorders. It was noted, that the alpha wave amplitude and frequency could indicate the cognitive, creative and intuitive abilities of a person.

Alzheimer’s disease as the cerebral cortex disorder

Objectives – to highlight the structure, function and localization of Alzheimer’s disease and to specify cognitive impairments related to it. Material and methods. The anatomic data of human brain structure were used. Results. The patterns of memory formation in the brain cortex are investigated. The brain cortex is presented as a type of syncytium consisting of elementary neural structures – cyclic neuronal circuits – memory elements. All cyclic neuronal circuits in a brain cortex are functionally interconnected. The connections between the neuronal circuits can be determined (imprinted) and stochastic (random). The intensity of stochastic communications defines the person's potential for creativity. The impairment of cyclic neuronal circuit connections results in either Alzheimer’s disease or in senile dementia of Alzheimer’s type. Conclusion. In case the cortex is considered as the syncytium, the memory storage element, it can be the reason of the human creativity. It is shown that the failure of the information transfer in the cortex syncytium or neurons destruction in the neuronal network results in Alzheimer’s disease or in senile dementia of Alzheimer’s type.

Relationship between equilibrium potential and radius of lanthanides electrolyzed on the zinc cathode

Abstract The electrochemical behavior of lanthanide elements deposited on liquid zinc cathodes was studied using cyclic voltammetry (CV) and open circuit chronopotentiometry (OCP). We observed a “bimodal effect” in the equilibrium deposition potentials of zinc with lanthanides. A mathematic equation is derived to illustrate the relationship between the equilibrium potential of the intermetallic compounds formed by lanthanide elements and zinc and their atomic radius. This equation is not only applicable to lanthanide elements but also hold for other elements such as alkali metal lithium, alkaline earth metal magnesium, calcium and transition metal niobium, which have crucial theoretical significance for the electrolysis of intermetallic compounds, the separation, and extraction of metals.

Design Methodology for Multiple Output Combinational Circuits Using Cyclic Combinational Technique

Conventional combinational circuits are generally acyclic (feed-forward) but these circuits can have feedbacks (cycles) which will give more minimized expressions as compared to conventional combinational circuits. Deliberate incorporation of such cycles or feedbacks in conventional combinational circuits eventually results in reduction in number of literals in the expression of the combinational circuits. The reduction in literal counts decreases the number of gates required to implement the expressions of the combinational circuits. Hence, the decrease in number of gates leads to reduction in transistor counts or layout area for the circuits. A cyclic combinational circuit (CCC) is defined as the circuit whose output depends on present inputs only, but at the same time contains one or more feedbacks (cycles). This paper presents a simplified methodology for introduction of cycles (feedbacks) and finding expressions for the CCC. The methodology is applied on LGSynth93 benchmark circuits and a reduction up to 28% in literal counts for expressions of CCC was found which is higher than the reduction achieved by other methodologies. Further the methodology is applied to implement binary comparator which has got three multiple outputs using cyclic combinational technique. The circuits are verified through simulation in cadence virtuoso tools using 45[Formula: see text]nm technology. Based on simulation results, performance parameters like power consumption, propagation delay and layout area of CCC are compared with the conventional circuits.

A Novel Methodology for Design of Cyclic Combinational Circuits

A Novel Methodology for Design of Cyclic Combinational Circuits

Timing Path-Driven Cycle Cutting for Sequential Controllers

Power and performance optimization of integrated circuits is performed by timing-driven algorithms that operate on directed acyclic graphs. Sequential circuits and circuits with topological feedback contain cycles. Cyclic circuits must be represented as directed acyclic graphs to be optimized and evaluated using static timing analysis. Algorithms in commercial electronic design automation tools generate the required acyclic graphs by cutting cycles without considering timing paths. This work reports on a method for generating directed acyclic circuit graphs that do not cut the specified timing paths. The algorithm is applied to over 125 benchmark designs and asynchronous handshake controllers. The runtime is less than 1 second, even for even the largest published controllers. Circuit timing graphs generated using this method retain the necessary timing paths, which enables circuit validation and optimization employing the commercial tools. Additional benefits show these designs are on an average a third in size, operate 33.3% faster, and consume one-fourth the energy.

Anodic Protection of Carbon Steel AISI 1006 Using the Binder of Undoped Polyaniline

The use of intrinsically conductive polymers such as polyaniline (PAni) has been presented as an alternative protective coating against corrosion, it intensifies the effect of anodic passivation and protection of the material. Given the difficulty in obtaining films of polyaniline in the oxidized form and driver in a self-supported and cohesive on the surface of metal substrates. Was held the undoped of the polymer, with the use of NH4OH solution to passing the PAni oxidized state and non-conducting polyaniline emeraldine base known as PAni EB. The complete mixture of PAni EB, organic solvent and plasticizer 4-chloro-3-methylphenol, allowed to obtain a resin. This was applied in AISI 1006 steel plates with the aid equipment Spin Coater. The film was characterized by thermal analysis TGA, where it was found that the coating is the result of the reaction components, predominantly the structure of PAni EB. The electrochemical tests of Cyclic Voltammetry and Potential Open Circuit were carried out in 2 molL-1H2SO4solution, which indicated the formation of redox couple polymer-metal, which provides the formation of passivating oxides, which allow the metal anodic protection against corrosion.

Four-Valued Reasoning and Cyclic Circuits

Allowing cycles in a logic circuit can be advantageous, for example, by reducing the number of gates required to implement a given Boolean function, or a set of functions. However, a cyclic circuit may easily be ill behaved. For instance, it may have some output wire oscillation instead of reaching a steady state. Propositional three-valued logic has long been used in tests for good behavior of cyclic circuits; a symbolic evaluation method known as ternary analysis provides one criterion for good behavior under certain assumptions about wire and gate delay. We revisit ternary analysis and argue for the use of four truth values. The fourth truth value allows for the distinction of undefined and underspecified behavior. Ability to under specify behavior is useful, because, in a quest for smaller circuits, an implementor can capitalize on degrees of freedom offered in the specification. Moreover, a fourth truth value is attractive because, rather than complicating (ternary) circuit analysis, it introduces a pleasant symmetry, in the form of contra-duality, as well as providing a convenient framework for manipulating specifications. We use this symmetry to provide fixed point results that clarify how two-, three-, and four-valued analyses are related, and to explain some observations about ternary analysis.

A quantum error-correction circuit based on cyclic code

In this paper, the cyclic code of the classic circuit is transformed and transplanted; then, the quantum encoding scheme based on cyclic code and quantum error-correction circuit is constructed. The proposed circuit can correct one-bit error, and the use of redundant bits to encode more than one-bit quantum information breaks the previous limitations of many bits encoding a quantum bit. Compared with the existing coding circuits (Shor code, Steane code and five stable subcode), it shows obvious superiority in the quantum coding efficiency and transmission efficiency.

The Synthesis of Cyclic Dependencies with Boolean Satisfiability

The accepted wisdom is that combinational circuits must have acyclic (i.e., feed-forward) topologies. Yet simple examples suggest that this is incorrect. In fact, introducing cycles (i.e., feedback) into combinational designs can lead to significant savings in area and in delay. Prior work described methodologies for synthesizing cyclic circuits with Sum-Of-Product (SOP) and Binary-Decision Diagram (BDD)-based formulations. Recently, techniques for analyzing and mapping cyclic circuits based on Boolean satisfiability (SAT) were proposed. This article presents a SAT-based methodology for synthesizing cyclic dependencies. The strategy is to generate cyclic functional dependencies through a technique called Craig interpolation. Given a choice of different functional dependencies, a branch-and-bound search is performed to pick the best one. Experiments on benchmark circuits demonstrate the effectiveness of the approach.

Cyclic Boolean circuits

A Boolean circuit is a collection of gates and wires that performs a mapping from Boolean inputs to Boolean outputs. The accepted wisdom is that such circuits must have acyclic (i.e., loop-free or feed-forward) topologies. In fact, the model is often defined this way–as a directed acyclic graph (DAG). And yet simple examples suggest that this is incorrect. We advocate that Boolean circuits should have cyclic topologies (i.e., loops or feedback paths). In other work, we demonstrated the practical implications of this view: digital circuits can be designed with fewer gates if they contain cycles. In this paper, we explore the theoretical underpinnings of the idea. We show that the complexity of implementing Boolean functions can be lower with cyclic topologies than with acyclic topologies. With examples, we show that certain Boolean functions can be implemented by cyclic circuits with as little as one-half the number of gates that are required by equivalent acyclic circuits. We also show a quadratic upper bound: given a cyclic Boolean circuit with m gates, there exists an equivalent acyclic Boolean circuit with m2 gates.

A Comparative Study of the Electrooxidation of Ethylene Glycol on Transition Metal Electrodes in Alkaline Solution

Electrodes made of group VIII and IB metals were examined for their redox process and electrocatalytic activities towards the oxidation of ethylene glycol in alkaline solutions. The method of cyclic voltammetery (CV) and Open circuit potentials measurement (OCP) was employed. It is found that considerable electrooxidation current are observed for silver and copper but lower anodic overpotential for oxidation is obtained for gold and platinum. Oxide layer produced on the surface of all electrodes in alkaline solution under anodic scan participates in ethylene glycol electrooxidation. Oxidation current observed in the reverse scans for platinum and gold are higher than those observed in forward potential scan. Open circuit potential measurements have shown the interaction of ethylene glycol and electrodes.

Constructive Boolean circuits and the exactness of timed ternary simulation

We classify gate level circuits with cycles based on their stabilization behavior. We define a formal class of combinational circuits, the constructive circuits, for which signals settle to a unique value in bounded time, for any input, under a simple conservative delay model, called the up-bounded non-inertial (UN) delay. Since circuits with combinational cycles can exhibit asynchronous behavior, such as non-determinism or metastability, it is crucial to ground their analysis in a formal delay model, which previous work in this area did not do. We prove that ternary simulation, such as the practical algorithm proposed by Malik, decides the class of constructive circuits. We prove that three-valued algebra is able to maintain correct and exact stabilization information under the UN-delay model, and thus provides an adequate electrical interpretation of Malik's algorithm, which has been missing in the literature. Previous work on combinational circuits used the upbounded inertial (UI) delay to justify ternary simulation. We show that the match is not exact and that stabilization under the UI-model, in general, cannot be decided by ternary simulation. We argue for the superiority of the UN-model for reasons of complexity, compositionality and electrical adequacy. The UN-model, in contrast to the UI-model, is consistent with the hypothesis that physical mechanisms cannot implement non-deterministic choice in bounded time. As the corner-stone of our main results we introduce UN-Logic, an axiomatic specification language for UN-delay circuits that mediates between the real-time behavior and its abstract simulation in the ternary domain. We present a symbolic simulation calculus for circuit theories expressed in UN-logic and prove it sound and complete for the UN-model. This provides, for the first time, a correctness and exactness result for the timing analysis of cyclic circuits. Our algorithm is a timed extension of Malik's pure ternary algorithm and closely related to the timed algorithm proposed by Riedel and Bruck, which however was not formally linked with real-time execution models.

The mechanical generation of fault trees for reactive systems via retrenchment II: clocked and feedback circuits

Abstract The retrenchment approach to the mechanical construction of fault trees, introduced in the first paper for combinational logic circuits, is extended to handle clocked circuits and then feedback circuits. The temporal behaviour of clocked circuits is captured using their causal relations, and the potentially unbounded behaviour of cyclic circuits is decomposed into an iteration over their acyclic counterparts. The repercussions of all this for the theory of retrenchment are elaborated. For clocked circuits, the techniques we present allow glitches and other transient errors to be properly described. For feedback circuits, the plethora of behaviours that can occur, give rise to infinitary fault trees of an appropriate kind. All this paves the way for automated fault tree generation for reactive systems.

Ferredoxin Molecular Thin Film with Intrinsic Switching Mechanism for Biomemory Application

A biomemory device consisting of cysteine modified ferredoxin molecules which possess a memory effect via a charge transfer mechanism was developed. For achieving an efficient bioelectronic device, cysteine modified ferredoxin was developed by embodying cysteine residues in ferredoxin by site--directed mutagenesis method to directly coordinate with the gold (Au) surface without use of any additional linkers. The thin film formation of ferredoxin molecules on Au electrode is confirmed by surface plasmon resonance (SPR) spectroscopy and scanning tunneling microscope (STM). Cyclic voltammetry (CV) and open circuit potential amperometry (OCPA) methods were used to verify the memory switching characteristics of the fabricated device. The charge transfer between ferredoxin protein molecules and Au electrode enables a bi-stable electrical conductivity allowing the system to be used as a digital memory device. Data storage is achieved by applying redox voltages which are within the range of -500 mV. These results suggest that the proposed device has a function of memory and can be used for the construction of a nano-scale bioelectronic device.

Transforming Cyclic Circuits Into Acyclic Equivalents

Designers and high-level synthesis tools can introduce unwanted cycles in digital circuits, and for certain combinational functions, cyclic circuits that are stable and do not hold state are the smallest or most natural representations. Cyclic combinational circuits have well-defined functional behavior yet wreak havoc with most logic synthesis and timing tools, which require combinational logic to be acyclic. As such, some sort of cycle-removal step is necessary to handle these circuits with existing tools. We present a two-stage algorithm for transforming a combinational cyclic circuit into an equivalent acyclic circuit. The first part quickly and exactly characterizes all combinational behavior of a cyclic circuit. It starts by applying input patterns to each input and examining the boundary between gates whose outputs are and are not defined to find additional input patterns that make the circuit behave combinationally. It produces sets of assignments to inputs that together cover all combinational behavior. This can be used to report errors, as an optimization aid, or to restructure the circuit into an acyclic equivalent. The second stage of our algorithm does this restructuring by creating an acyclic circuit fragment from each of these assignments and assembles these fragments into an acyclic circuit that reproduces all the combinational behavior of the original cyclic circuit. Experiments show that our algorithm runs in seconds on real-life cyclic circuits, making it useful in practice.

INVESTIGATION ON CYCLIC RECIPROCAL DERIVATIVE CHRONOPOTENTIOMETRY. IV. CYCLIC CONTROLLED LOGIC CIRCUIT AND ANOTHER SIMPLE RECIPROCAL SIMULATOR

This paper reports a cyclic controlled logic circuit employed in cyclic reciprocal derivative chronopotentiometry for providing cyclic sweep direct current. It can be achieved by utilizing A 555 Schmitt trigger, coupled with operational amplifiers. Another simpler reciprocal simulator using a diode as an antilog amplifier is also presented.