OR Operator Research Articles

Posbist fault tree analysis of coherent systems

Abstract When the failure probability of a system is extremely small or necessary statistical data from the system is scarce, it is very difficult or impossible to evaluate its reliability and safety with conventional fault tree analysis (FTA) techniques. New techniques are needed to predict and diagnose such a system's failures and evaluate its reliability and safety. In this paper, we first provide a concise overview of FTA. Then, based on the posbist reliability theory, event failure behavior is characterized in the context of possibility measures and the structure function of the posbist fault tree of a coherent system is defined. In addition, we define the AND operator and the OR operator based on the minimal cut of a posbist fault tree. Finally, a model of posbist fault tree analysis (posbist FTA) of coherent systems is presented. The use of the model for quantitative analysis is demonstrated with a real-life safety system.

On left and right uninorms on a finite chain

The main concern of this paper is to introduce and characterize the class of operators on a finite chain L, having the same properties of pseudosmooth uninorms but without commutativity. Moreover, in this case it will only be required the existence of a one-side neutral element. These operators are characterized as combinations of AND and OR operators of directed algebras (smooth t-norms and smooth t-conorms) and the case of pseudosmooth uninorms is retrieved for the commutative case.

Stiffness and inertia multicriteria evolutionary structural optimisation

In continuation of the recent development of Evolutionary Structural Optimisation (ESO) applied to the simultaneous objective to maximise the natural frequency and to minimise the mean compliance, presents the Multicriteria ESO optimisation of two new criteria. This has been done with the use of four different multicriteria methods. Three examples have been used to verify the usefulness and capability of these methods applied to ESO in the context of the aforementioned criteria. Concluded that the ESO weighting method is proficient in presenting the designer with a range of options (of Pareto attribute) taking into account multiple criteria, and the global criterion method has the tendency to produce shapes and topologies that resemble that of the weighted 50 per cent: 50 per cent method. Likewise, the logical OR operator method produced designs that corresponded directly to those of 100 per cent stiffness weighted criteria. No clear resemblance could be concluded with the case of the logical AND operator method.

Extended Decision Tree with GP’s Function Nodes Including “OR Operator”

Extended Decision Tree with GP’s Function Nodes Including “OR Operator”

Robustness of a gene regulatory circuit.

Complex interacting systems exhibit system behavior that is often not predictable from the properties of the component parts. We have tested a particular system property, that of robustness. The behavior of a system is termed robust if that behavior is qualitatively normal in the face of substantial changes to the system components. Here we test whether the behavior of the phage lambda gene regulatory circuitry is robust. This circuitry can exist in two alternative patterns of gene expression, and can switch from one regulatory state to the other. These states are stabilized by the action at the O(R) region of two regulatory proteins, CI and Cro, which bind with differential affinities to the O(R)1 and O(R)3 sites, such that each represses the synthesis of the other one. In this work, this pattern of binding was altered by making three mutant phages in which O(R)1 and O(R)3 were identical. These variants had the same qualitative in vivo patterns of gene expression as wild type. We conclude that the behavior of the lambda circuitry is highly robust. Based on these and other results, we propose a two-step pathway, in which robustness plays a key role, for evolution of complex regulatory circuitry.

Pictorial Query Specification for Browsing Through Spatially Referenced Image Databases

A pictorial query specification technique that enables the formulation of complex pictorial queries for browsing through a collection of spatially referenced images is presented. It is distinguished from most other methods by the fact that in these methods the query image specifies a target database image in its entirety whereas in our approach the query image specifies the combination of objects that the target database image should contain rather than being treated as a whole image. The query objects are represented by shape features although other features such as color, texture or wavelets could also be used. Using our technique, it is possible to specify which particular objects should appear in the target images as well as how many occurrences of each object are required. Moreover, it is possible to specify the minimum required certainty of matching between query-image objects and database-image objects, as well as to impose spatial constraints that specify bounds on the distance between objects and the relative direction between them. These spatial constraints can also be used to specify other topological relations such as enclosure, intersection, overlap, etc. Each pictorial query is composed of one or more query images. Each query image is constructed by selecting the required query objects and positioning them according to the desired spatial configuration. Boolean combinations of two or more query images are also possible by use of AND and OR operators. A query image may be negated in order to specify conditions that should not be satisfied by the database images that are retrieved successfully. In addition, a capability is provided to specify whether the same instance of an object is to be used when it appears in more than one of the query images that make up the pictorial query, or whether two different instances are allowed. Several example queries are given that demonstrate the expressive power of this query specification method. An algorithm for retrieving all database images that conform to a given pictorial query specification is presented. The user interface for using this pictorial query specification method to browse the results in a map image database application is described and illustrated via screen shots.

Fuzzy measures for sensor data fusion in industrial recycling

During recent years it has become more and more obvious that we need to take care of products when they are worn out if we are to be more environmentally responsible. To make this possible much of the related work has to be performed in an automized way. When a disassembly process is automized a number of sensors is needed. These sensors gather a large amount of information which must be fused in an effective way. To this end we need a method that is fast, flexible, robust and easy to adapt to all kind of sensors. The first attribute (fastness) can be obtained by using a distributed sensor data processing architecture with local processors which pre-process data close to the sensors. The other attributes are obtained by using a fusion algorithm based on a novel fuzzy operator. In this article, this fuzzy operator is described and its properties investigated. A simulation is performed, applying the fuzzy operator to a sensor-based classification by size of electrical motors aimed for disassembly. The simulation clearly demonstrates the superiority of our fuzzy operator when compared to common AND and OR operators.

Using formal logic to classify vegetation

Suggestions are made to define vegetation units by using formal logic. The characteristics that are used for the definition are logically combined using the AND, OR and NOT operators in such a way that releves can be unequivocally allocated to vegetation units. Among all the characteristics of vegetation species groups are best suited to present allocation schemes for the Braun-Blanquet-system. It is shown that definition gaps within the system can be completely avoided by providing formal allocation rules.

Multilevel fault tree analysis using fuzzy numbers

This paper applies fuzzy concepts to fault tree analysis (FTA), where the basic events are considered as fuzzy numbers, and shows that n-ary fuzzy AND and OR operators are used to evaluate the possibility of systems failure. L− R type fuzzy numbers can be defined completely by a triplet ( m, α, β) and the value m is also considered a triangular fuzzy number (TFN). The comparison method is based on the dominance property. By the dominance criteria, each value m is determined to obtain the optimistic and pessimistic possibilities of the system accident. We can extend major and minor TFNs to fuzzy FTA for better results. The goal of this paper is to replace probabilistic considerations in the FTA by the possibilistic ones and to reduce the difficulty arising from the inexact and insufficient information of the distribution functions of basic event.

The isolated N-terminal DNA binding domain of thec repressor of bacteriophage16-3 is functional in DNA binding in vivo and in vitro

The 197 amino acid c repressor of the temperate Rhizobium meliloti phage 16-3 still regulates the OR operator of the phage after removal of its carboxyl terminal region. When cloned in the low-copy-number plasmid pGA46, a severely truncated variant (R1-77), which retains only the first 77 amino acids of the intact protein, repressed in vivo transcription from the phage promoter PR. When the R1-77 repressor was fused to E. coli beta-galactosidase, the hybrid protein bound OR operator DNA in vitro. The behavior of fusion proteins derived from a point mutant is consistent with the assignment of DNA binding specificity to the amino-terminal region. Furthermore two repressor alleles bearing ts mutations that mapped in the R1-77 region (near a helix-turn-helix motif) were also temperature sensitive for regulation of the OR site, while an 18 bp "in frame" deletion mutant, which mapped in the carboxyl terminal segment, regulated the OR operator in wild-type fashion. The carboxyl terminal region of the repressor is however necessary for the control of lysogenic development of 16-3.

Fault tree analysis based on fuzzy logic

This paper considers the relative frequencies of basic events determining the safety of such a system as fuzzy numbers and uses instead of probabilistic possibilistic considerations for evaluating the mean values and the tolerances for the frequency of head events. Using standard approximations for the membership function expressions for the n-ary possibilistic, AND, OR and NEG operators are derived allowing a straightforward evaluation of the possibility distributions of the head events. In the second part, the paper intends to show the application of the new approach to the safety analysis of chemical systems. The procedure is shown in the case of a reactor system. The detailed analysis includes the program list of the procedure written in CSMP III.

On ordered weighted averaging aggregation operators in multicriteria decisionmaking

The author is primarily concerned with the problem of aggregating multicriteria to form an overall decision function. He introduces a type of operator for aggregation called an ordered weighted aggregation (OWA) operator and investigates the properties of this operator. The OWA's performance is found to be between those obtained using the AND operator, which requires all criteria to be satisfied, and the OR operator, which requires at least one criteria to be satisfied. >

A digital PN signal correlator with improved performance

Abstract A new digital PN signal correlator, which is more suitable and easier to implement, using digital integrated circuits is proposed in this paper. This digital PN signal correlator consists of a bit matched filter, an exclusive OR operator, and a counter. The statistical properties and the error rate performance of the digital PN signal correlator are analyzed and discussed in detail. The results show that this digital PN signal correlator will suffer slight SNR degradation., (maximum degradation is about —2 dB) as compared with the conventional analog PN signal correlator for small values of Eb/N0 (<0.75), but for high Eb/N0, even a very significant SNR improvement can be achieved.

Multistate reliability analysis

The binary AND and OR operators are generalized to multistate systems with multistate components, by developing multistate operators which obey the Commutative and the Associative laws. In systems with such operators, components can be rearranged internally in any arbitrary way without affecting the mapping of the component states onto the state of the system. In addittion, all components, all subsystems and the system itself have the same set of states. Such systems are called homogeneous. Operators of homogeneous systems can be described by either their truth table or by the ranking of their states in order of relative dominance. If a homogeneous system is also coherent, then the mapping of the component states onto the system state, and the calculation of the probabilities of system states from those of the component states, become very simple. The sets of operators for 3-state and 4-state homogeneous coherent systems are given. In an example, the Auxiliary Feedwater System of a nuclear power plant is modeled as a homogeneous coherent multistate system composed of homogeneous coherent multistate subsystems, and its reliability is calculated.

Operators and promoters in the ORregion of phage 434

The OR operator region of phage 434 contains three 14 bp blocks with sequence ACAAGA-A--TTGT which are presumed to be the 434 repressor recognition sites. Operator constitutive mutations are located in two of these blocks, while a mutation affecting repressor levels in the lysogenic state is located in the third. Two transcripts obtained in vitro, one leftwards and one rightwards, are tentatively identified as the Prm and PR transcription starts. the arrangement of the 434 operator region appears to be very similar to that of the OR of phage lambda.

Implementation of a transcribed exclusive OR operator

Transcribed exclusive-OR forms are obtained from block negation, that substitutes a NAND (NOR) gate for a AND (OR) gate. Usual tricks related to expressions containing XOR operator can be deduced from the transcription of the dual input XOR operator and from the properties of transcribed forms. Examples show the implementation of these properties for minimizing XOR expressions or optimizing NAND-NOR networks.

Algebraic optimisation of NAND-NOR switching circuits

This paper presents an algebraic optimisation of NAND-NOR switching circuits. Logic functions are transcribed by AND into NAND conversion. Only the available variables may appear in transcribed forms written with AND and OR operators and brackets; special relations make this process convenient.

Sequence of the OR operator of phage lambda.

A sequence of 79 nucleotides from the lambda OR operator is obtained by primed transcription of repressor protected DNA fragments. The sequence contains the primary repressor binding site plus partial duplications which can be interpreted as secondary repressor binding sites.

Sulla sintesi di reti NAND o nor a molti livelli

Some authors have proved that a minimal two-level NAND or NOR network can be obtained by the convetional procedures for determining minimal normal forms. But when either the complements of some input variables are not available or the gates have a limited number of inputs, the two-level synthesis is generally impossible; and no procedure has been described for the minimal sunthesis of networks having more than two levels of gates. In this paper some new procedures are described for the synthesis of NAND or NOR networks having more than two levels of gates. In the first sections the properties are briefly described, by which a NAND or NOR expression is equivalent to a conventional expression containing only the AND and OR operators; also, the problem of determining a minimal two-level NAND or NOR network is summarized. Then the synthesis of three-level NAND or NOR networks is considered, in case that both the true and complemented values of input variables are available, and the gates can have an unlimited number of inputs (condition 1). A new procedure is described which makes it possible to find one of the minimal NAND or NOR networks, having a tree-shaped structure, and which gives also quasi-minimal solutions for the general case in which the output of a gate can be connected to the inputs of more than one gate of the next level. The procedure derives from the methods described in a preceding paper by the present author for determining the minimal «sums of products of sums» of an assigned function; but some properties and the particular definition of cost make it possible to apply a computation technique, which simplifies this problem considerably. Then the synthesis problem is considered when the gates can have an unlimited number of inputs but the complements of some of the input variables are not available (condition 2). In this case the two-level synthesis is generally impossible (a simple necessary and sufficient condition for a two-level solution to exist is proved); on the contrary, a three-level NAND or NOR network always exists, which implements the assigned function. This network can be determined with the procedure which has been described for determining the minimal three-level networks in condition 1, but the new conditions simplify the problem and a remarkable reduction of the computation work is possible. Lastly the following cases are considered: In these cases a two- or a three-level synthesis may be impossible, but one can always verify whether a two- or a three-level network implementing the assigned function exists. However a simple procedure is described, which always makes it possible to find a quasi-minimal solution characterized by more than three levels of gates.