Basic Logic Operations Research Articles

Digital processing with a three-state molecular switch.

Certain molecular switches respond to input stimulations producing detectable outputs. The interplay of these signals can be exploited to reproduce basic logic operations at the molecular level. The transition from simple logic gates to complex digital circuits requires the design of chemical systems able to process multiple inputs and outputs. We have identified a three-state molecular switch that responds to one chemical and two optical inputs producing two optical outputs. We have encoded binary digits in its inputs and outputs applying positive logic conventions and demonstrated that this chemical system converts three-digit input strings into two-digit output strings. The logic function executed by the three-state molecular switch is equivalent to that of a combinational logic circuit integrating two AND, two NOT, and one OR gate. The three states of the molecular switch are a colorless spiropyran, a purple trans-merocyanine, and its yellow-green protonated form. We have elucidated their structures by X-ray crystallography, (1)H NMR spectroscopy, COSY and NOE experiments, as well as density functional calculations. The three input stimulations controlling the interconversion of the three states of the molecular switch are ultraviolet light, visible light, and H(+). The two outputs are the absorption bands in the visible region of the two colored states of the molecular switch. We have monitored the switching processes and quantified the associated thermodynamic and kinetic parameters with the aid of (1)H NMR and visible absorption spectroscopies.

Digital Processing and Communication with Molecular Switches

The tremendous pace in the development of information technology is rapidly approaching a limit. Alternative materials and operating principles for the elaboration and communication of data in electronic circuits and optical networks must be identified. Organic molecules are promising candidates for the realization of future digital processors. Their attractive features are the miniaturized dimensions and the high degree of control on molecular design possible in chemical synthesis. Indeed, nanostructures with engineered properties and specific functions can be assembled relying on the power of organic synthesis. In particular, certain molecules can be designed to switch from one state to another, when addressed with chemical, electrical, or optical stimulations, and to produce a detectable signal in response to these transformations. Binary data can be encoded on the input stimulations and output signals employing logic conventions and assumptions similar to those ruling digital electronics. Thus, binary inputs can be transduced into binary outputs relying on molecular switches. Following these design principles, the three basic logic operations (AND, NOT, and OR) and more complex logic functions (EOR, INH, NOR, XNOR, and XOR) have been reproduced already at the molecular level. Presently, these simple “molecular processors” are far from any practical application. However, these encouraging results demonstrate already that chemical systems can process binary data with designed logic protocols. Further fundamental studies on the various facets of this emerging area will reveal if and how molecular switches can become the basic components of future logic devices. After all, chemical computers are available already. We all carry one in our head!

Flexible parallel implementation of logic gates using chaotic elements.

We demonstrate the basic principles for the direct and flexible implementation of all basic logical operations utilizing low dimensional chaos. Then we generalize the concept to high dimensional chaotic systems, and show the parallelism inherent in such systems. As a case study we implement the proposed parallel computing architecture to obtain parallelized bit-by-bit addition with a two-dimensional chaotic neuronal and a three-dimensional chaotic laser model.

Second Quantization Representation of Quantum Logic Gate Transformations**The project supported by the Youth Sci-Tech “Qimingxing” Program of Shanghai and the University Youth Science Foundation of Shanghai of China

By using the theory of multimode linear transformation in Fock space, we offer an effective method to study the quantum logic gates based on fermion states. The forms of some basic quantum logic operations are also obtained.

Tutorial: Petri nets as a graphical description medium for many reliability scenarios

One of the basic problems of dependability modeling is the adequate abstraction of real-world technological problems to the principle terms of reliability/safety scenarios. This concerns primarily the definition of components and of faults on different system levels. Given these terms the rest of any modeling needs basic logical operations, mostly AND and OR, and delays, and often some counting (of time or events). All of these basic operations are offered by a fairly simple kind of Petri net (PN), i.e., timed stochastic Petri nets, allowing also for the modeling of immediate activities and of such with a deterministic delay. In this half-tutorial paper it is shown how such Petri nets modeling, i.e., the construction of the relevant nets, works in practice. No math will be needed for that. Several typical engineering virtues are needed; primarily imagination as to how to (i) find simple solutions, since often nonelegant solutions can be correct too, (ii) compose larger PN from elementary building blocks, and (iii) the ability to model the real world by interpreting the so-called tokens of a PN intelligently in different places of one and the same PN. In the appendix it is shown how the PN can also help in the analytical analysis of nonrepairable systems. In that context they are superior to state graphs since they show state durations explicitly.

Assessing portal design skills in the radiation oncology interactive case management examination.

The American Board of Radiology is developing a computerized interactive case management examination to be used to evaluate the clinical skills of radiation oncologists. In the past, these skills have been evaluated by a pencil and paper written examination and an oral examination. With the increasing capabilities of computers, these skills can be easily, and perhaps even better, evaluated digitally. The aim is to develop an examination, which will be based on actual clinical cases, and be interactive so that it better mimics the clinical practice of a radiation oncologist than a written examination. It will also be less labor-intensive and less expensive than an oral examination. One of the most important skills of a radiation oncologist is the ability to design treatment portals that will encompass the entire cancer and yet minimize the irradiation of critical tissues and normal organs. Important parameters for radiation oncologists include the direction of the treatment beam, the size and shape of the portals, and the location of the margins of the field relative to patient anatomy and tumor location. In order to evaluate a physician's ability to design treatment portals, the computer-based examination has the capability to interactively construct field lines. The computer interface allows the candidate to draw field lines on a digitized x-ray image in a manner similar to practice. After the candidate illustrates the field lines, the evaluation of the response must be performed quickly to avoid interrupting the flow of the examination. The answer key is stored as a lossless compressed image. The key contains three regions consisting of (1) the must include region, which contains the tumor; (2) the must-exclude region, which contains tissues that if damaged would affect patient vitality and quality of life; and (3) the envelope of acceptable curves. Each region is assigned a unique byte code. The candidate's response is assigned a fourth byte code. Using basic logic operations, the response is swiftly evaluated. The scoring algorithm scores a candidate's action as correct if his/her drawn area encompasses all of the "must-include region" and is within the "envelope of acceptable curves." It scores a candidate's action as incorrect if his/her drawn area overlaps any part of the "exclude region" and/or exceeds at any point the "envelope of acceptable curves."

Coherent charge qubits based on GaAs quantum dots with abuilt-in barrier

We investigated the use of quantum bits (qubits) - semiconductor quantum dotscontaining one electron and each consisting of twotunnel-connected parts - as basic elements ofthe quantumcomputer. The numerical solution of aSchrödinger equation taking account of the Coulomb field ofadjacent electrons shows that in such structures therealization of a full set of basic logic operations, which arenecessary for fulfillment of quantum computations, is possible.Durations of one- and two-qubit operations versus qubit geometryare obtained. Decoherence rates due to spontaneous emission ofphonons and acoustic phonons (both piezoelectric anddeformation) are evaluated. Analysis of these rates shows theproposed qubit to be coherent enough to work for an unlimited time.

A network model based on qubitlike neuron corresponding to quantum circuit

Investigations into quantum computations have begun from the pioneering theoretical studies of Feynman, Deutsch, and others, and detailed studies have been done since the discovery of a quantum algorithm which can solve the problem of factorizing a large integer in polynomial time by Shor in 1994. Recently, the existence of nonalgorithmic quantum computations in microtubules inside a neural circuit has been debated, resulting in the proposal of the concept of the quantum neural computation theory, although detailed studies have not as yet been made. In this paper, in order to construct a new framework for describing the cohesiveness of the distribution and synthesis inherent in a neural network, a neural state is described quantum dynamically and a qubitlike neural network corresponding to the quantum circuit of quantum computations is studied. Specifically, a qubitlike neural network is constructed for a 3-bit quantum circuit, which is the minimum quantum logical gate describing all basic logical operations, and in this model we investigate how to determine circuit parameters by learning. © 2000 Scripta Technica, Electron Comm Jpn Pt 3, 83(10): 67–73, 2000

Computational verb systems: a new paradigm for artificial intelligence

Computational verb systems can help machines to implement, understand and use verbs as human perception of dynamics. By using computational verbs we can embed dynamical experiences of human experts into artificial intelligence. Computational verbs, which are models of verbs in nature languages, are basic building blocks of computational verb systems. In this paper, computational verbs are used to represent dynamical knowledge embedded by verbs as a new framework of knowledge representation. BE-transformations are used to transform statements containing dynamical verbs into statements only containing static verb BE; namely, BE-propositions. Based on BE-transformations, the computational verb logic can be built. Furthermore, reasoning with computational verbs can be built based on BE-transformations and basic verb logic operations.

Computational verb systems: Verb logic

Computational verb systems are new platforms for artificial intelligence. They embed the dynamical knowledge expressed by dynamical experiences of human brains into machines by using pattern thinking. In this paper, the relationship defined by verbs in human natural languages is modeled by computational verb logic (verb logic for short). To unify different verbs with different contexts into comparable standard forms, the concepts of BE transformation and canonical BE transformation are given. The atomic and molecular verb sentences under canonical BE transformations are also defined for verb logic. The basic verb logic operations are given. Some examples are given to demonstrate the concepts of BE transformation and verb logic. ©1999 John Wiley & Sons, Inc.

Key step made toward molecular computing

The first organic molecule-based electronic components that perform some of the same basic logic operations used by Intel Pentium chips and other computer microprocessors have been developed by a collaborative group in California. The devices are a step toward a new generation of computers based on organic molecules instead of silicon, the solidstate material used in conventional computer chips. Organic molecule-based chips potentially offer greater miniaturizability and higher speed than silicon-based chips, which are rapidly approaching physical barriers that limit their performance. The new components were designed and constructed by chemistry professors James R. Heath and J. Fraser Stoddart of the University of California, Los Angeles; computer architect Philip J. Kuekes and physical chemist R. Stanley Williams of Hewlett-Packard Laboratories, Palo Alto, Calif.; and UCLA coworkers C. Pat Collier, Eric W. Wong, M. Belohradsky, and Frangisco M. Raymo, who reported on them in last week's Science [285,391...

Vague controller: A generalization of fuzzy logic controller

In this research, a vague controller (VC) is synthesized by using the notion of vague sets, which are a generalization of fuzzy sets and characterized by a truth-membership function and a falsity-membership function. The vague sets follow the basic set operations and logic operations defined for fuzzy sets, and are superior to fuzzy sets in that they could deal with the uncertainty encountered in real-world applications in a more natural way. Depending on the vague sets, the VC is developed as a generalization of fuzzy logic controller (FLC). The design procedures of the VC, which allow an arbitrary number of input variables, and each variable could have a distinct number of linguistic values, are outlined in this paper. In order to compensate the effort in constructing two series of membership functions for vague sets and to ease the difficulties in designing VCs, a new means of designating membership functions for VCs is also presented in this article. This method constructs a set of membership functions systematically by using only two parameters: number of linguistic values of a linguistic variable and shrinking factor. The membership functions generated by this method, shrinking-span membership functions (SSMFs), have different spans over the universe of discourse and, therefore, are more rational and more practical from the human expert's point of view.

Binary processing by spatially solitary wave steering in 2-D planar resonator structures

We show that solitary waves existing in nonlinear planar resonators illuminated under oblique incidence can be employed for all-optical binary processing. It is numerically demonstrated how the basic logical operations can be implemented.

An Approach to Diagnosis through Search of and/or/not Causal Graphs

The paper presents an approach to diagnosis of dynamic systems based on abductive analysis of causal structures. A basic model for representing causal behaviour of diagnosed systems is proposed; it has the form of an AND/OR/NOT causal graph allowing for specification of causality types reflecting the basic logical operations. A definition of diagnostic problem is formalized and search for possible diagnoses is discussed. The diagnostic process is regarded as a multistage procedure incorporating failure detection, search for possible diagnoses with use of tests, ordering and validation of diagnoses; the proposed model can be used in any of the above stages. Some new extensions of the presented approach include also introduction of diagnoses covering not only component faults but “wrong” compositions of control actions and operational conditions.

CONTROLLING MOTORS USING FUNCTIONAL BLOCK DIAGRAM (FBD) PROGRAMMING LANGUAGE

Abstract. Programmable Logic Controllers (PLCs) are industrial computers working with control structured system software equipped with input/output units and communication interfaces suitable for the implementation of command and control schemes of industrial automation systems. It was designed to replace relay control systems and the first commercial PLC was produced by Modicon in 1969. In those years, this device, designed to be used instead of relay control circuits, could only work with basic logic operation commands. After the successful introduction of the first commercial PLC in industry, companies such as Allen Bradley, General Electric, GEC, Siemens, Westinghouse produced PMKs [1]. For the implementation of this work, the 1512C CPU type of the S7-1500 PMK introduced in 2012 by the SIEMENS brand, which has made a small contribution to the PLC market, will be used. The Functional Block Diagram (FBD) programming language created according to the 61131-3 standard of the International Electrotechnical Commission is intended for the sequential operation of engines in the system to be built with the S7-1500 PLC. Networks will be created using 2 methods, "Set", "Reset" and "P", "N" commands, taking into account the electrical locking in the TIA (Totally Integrated Automation) Portal software to control and operate the engines sequentially. Keywords: PLC, IEC 61131-3, FBD, Set-Reset, Motor

Fuzzy-set based models of neurons and knowledge-based networks

We will introduce and study different fuzzy-set oriented computational models of neurons. The generic topologies of the neurons emerging there are significantly influenced by basic logic operators(AND, OR, NOT) encountered in the theory of fuzzy sets. The logical flavor of the proposed constructs is expressed in terms of operators used in their formalization and a way of their superposition in the neurons. The two broad categories of neurons embrace basic aggregation neurons (named AND and OR neurons) and referential processing units (such as matching, dominance, inclusion neurons). The specific features of the neurons are flexibly modeled with the aid of triangular norms. The inhibitory and excitatory characteristics are captured by embodying direct and complemented (negated) input signals. We will propose various topologies of neural networks put together with the use of these neurons and demonstrate straightforward relationships coming off between the problem specificity and the resulting architecture of the network. This limpid way of mapping the domain knowledge onto the structure of the network contributes significantly toward enhancements in learning processes in the network and substantially facilitates its interpretation.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Neural network model using interpattern association

This paper investigates a neural network model-interpattern association (IPA) model-in which the basic logical operations are used to determine the interpattern association (i.e., association between the reference patterns), and simple logical rules are applied to construct tristate interconnections in the network. Computer simulations for the reconstruction of similar English letters embedded in the random noise by the IPA model have shown improved performance compared with the Hopfield model. A 2-D hybrid optical neural network is used to demonstrate the usefulness of the IPA model. Since there are only three gray levels used in the interconnection weight matrix for the IPA model, the dynamic range imposed on a spatial light modulator is rather relaxed, and the interconnections are much simpler than the Hopfield model.

Optical implementation of parallel fuzzy logic

A multiple-imaging scheme with area-coding of input fuzzy variables and negations and thresholding of output intensity is proposed to perform basic fuzzy logic operations in parallel. Thus the pattern fuzzy logic described by a fuzzy logic function in disjunctive or conjunctive normal form can be easily realized in a two-stage optica system. The access of the required fuzzy logic function can be achieved by programming the lens-arrays and the thresholding devices. Simulations and experimental results are given, too.

Symbolic logic processor using cascaded liquid crystal televisions (LCTVs)

AbstractA shadow casting optical logic array processor using cascaded programmable liquid crystal televisions (LCTVs) is described. We have shown that the 16 basic logic operations can be easily achieved with this technique. A technique of performing two‐level logic function using a modified version of this proposed architectures is also given. We have shown that any two‐level logic function can be performed with this technique. The experimental demonstrations of this optical symbolic logic processor are also provided.

Comparisons between Active Properties of Distal Dendritic Branches and Spines: Implications for Neuronal Computations

The specific contributions of distal dendrites to the computational properties of cortical neurons are little understood and are completely ignored in most network simulations of higher brain functions. Compartmental models, based on realistic estimates of morphology and physiology, provide a means for exploring these contributions. We have pursued analysis of a model of synaptic integration in a distal dendrite bearing four spines, using a new general-purpose simulation program called SABER. We have analyzed this model under the assumption that the dendrite contains sites of impulse-generating membrane, and we have compared its responses to synaptic activation with the case of impulse-generating membrane located instead in the spine heads, as previously reported. Both types of models generate basic logic operations, such as AND, OR, and AND-NOT gates. Active spine heads require lower excitatory synaptic conductances, but active branch segments lead to larger responses in the soma. The transients recorded near the soma give no evidence of their origin in either active branch or active spines, indicating that the interpretation of experimental recordings with regard to sites of distal active responses must be viewed with caution. The results suggest the hypothesis that a hierarchy of logic operations is virtually inherent in the branching structure of dendritic trees of cortical pyramidal neurons. Inclusion of these properties in representations of cortical neurons would greatly enhance the computational power of neural networks aimed at simulating higher brain functions.