Maximum Number Of Occurrences Research Articles

Power Quality as a Reliability Problem for Electronic Equipment.

Power quality standards introduce the definitions of several power quality disturbances and define limits for their amplitudes, repetition rates and, or maximum number of occurrences in a time period. The definitions of those parameters result from the observation of the disturbance phenomena in the networks and are not related with the consequences of power quality disturbances in the reliability of electronic equipments. In this paper, are described the main reliability effects caused by power quality problems, in electronic equipment. The authors explain the physical limitations of power supplies, concerning power quality problems and developed a simple, low cost power quality analyser, designed for the evaluation of the parameters that are critical to the failure rates of electronic equipment.

Genetic and chaotic signatures in offspring – an encrypted generation of image family

With the rapid escalation of information technology and the internet, the digital image has turned out to be a vital medium for communication. Hence, there is an increasing demand to protect these digital images as they are transmitted over the insecure medium such as the Internet. This paper proposes the Genetic Algorithm influenced image encryption scheme. Both crossover and mutation operations were performed to enhance the statistical measures of the grayscale cipher images. Intra-pixel bit manipulation improved the diffusion property during mutation. Crossover accomplished the generation of offspring with the confluence of image intensities and keys. The chaotic Logistic and Tent maps provided improvement in keyspace through their role in the generation of initial seeds. Noticeably, the initial seeds were generated from the features of input image such as minimum & maximum number of occurrences of intensity and minimum & maximum intensity levels. In this regard, every image will accompany a unique key sequence as a session key which needs to be shared with the intended receiver for the distortion-free recovery of original images. Besides, the multi-point genetic crossover was employed for diffusion which resulted in the production of a couple of offspring. The Fitness test which decides the number of generations was executed by performing correlation and entropy analyses at a threshold of 0.01 and 7.99 for the former and later respectively. The investigational consequences authenticate that the proposed scheme not only reveals simple and optimised encryption, it is also defending against various distinctive attacks. The proposed image security solutions can be incorporated in banking, medical insurances, e-healthcare, and e-governance sectors for document confidentiality and integrity checking mechanisms.

Spatial and network characteristics of Irish cattle movements

Our aim was to examine, for the first time, the spatial and network characteristics of cattle movements between herds in the Republic of Ireland (ROI), to inform policy and research of relevance to the surveillance and management of disease in Irish cattle. We analysed movements in 2016 as discrete herd to herd pairings (degree), herd to herd pairings by date of move (contacts) and herd to herd pairings by date and individual animal (transfers), and looked at each of these as movements out of a herd (out degree, out contacts, out transfers) and into a herd (in degree, in contacts, in transfers). We found that the frequency distributions, by herd, of these six move types were all heavily right skewed but in the case of the ‘out’ data types more closely followed a log-normal than the scale free distribution often reported for livestock movement data. For each distinct herd to herd contact in a given direction, over 90 % occurred only once, whereas the maximum number of occurrences was 62. Herd-level Spearman rank correlations between inward moves (represented as in degree, in contacts, in transfers) and outward moves (out degree, out contacts, out transfers) were weak or even negative whereas correlations between different measures of outward moves or inward moves (e.g. out degree vs. out contacts, in transfers vs. in degree) were stronger. Correlations between these variables and the network measure betweenness varied between r = 0.513 and r = 0.587. Some herds took part in a relatively large number of movements whilst also retaining their cattle for long periods (> 100 days) between moves. In and out degree, contacts and transfers were mapped across Ireland on a 5 km grid, and additionally normalized per 1000 animals and per herd. We found considerable variation in the number of movements by county. Approximately half of transfers were conducted within a single county, but the number and distance of between county movements varied considerably by county of origin and county of destination, with the proportion of moves completed within a single county correlated with its size. Herds exchanging cattle via a market were generally further apart than when moves were made directly herd to herd. For contacts, the distances moved away from the herd were on average greater for origin herds in the west of ROI whereas distances moved to a herd were generally greater for destination herds in the centre-east and the north-west.

Approximating the DCJ distance of balanced genomes in linear time

BackgroundRearrangements are large-scale mutations in genomes, responsible for complex changes and structural variations. Most rearrangements that modify the organization of a genome can be represented by the double cut and join (DCJ) operation. Given two balanced genomes, i.e., two genomes that have exactly the same number of occurrences of each gene in each genome, we are interested in the problem of computing the rearrangement distance between them, i.e., finding the minimum number of DCJ operations that transform one genome into the other. This problem is known to be NP-hard.ResultsWe propose a linear time approximation algorithm with approximation factor O(k) for the DCJ distance problem, where k is the maximum number of occurrences of any gene in the input genomes. Our algorithm works for linear and circular unichromosomal balanced genomes and uses as an intermediate step an O(k)-approximation for the minimum common string partition problem, which is closely related to the DCJ distance problem.ConclusionsExperiments on simulated data sets show that our approximation algorithm is very competitive both in efficiency and in quality of the solutions.

Probabilistic Planning with Reduced Models

Markov decision processes (MDP) offer a rich model that has been extensively used by the AI community for planning and learning under uncertainty. However, solving MDPs is often intractable, which has led to the development of many approximate algorithms. In my dissertation work I introduce a new paradigm to handle this complexity by defining a family of MDP reduced models characterized by two parameters: the maximum number of primary outcomes per action that are fully accounted for and the maximum number of occurrences of the remaining exceptional outcomes that are planned for in advance. Reduced models can be solved much faster using heuristic search algorithms, benefiting from the dramatic reduction in the number of reachable states. This framework places recent work on MDP determinization in a broader context and lays the foundation for efficient and systematic exploration of the space of MDP model reductions. Progress so far work includes a formal definition of this family of MDP reductions, a continual planning paradigm to handle the case when the number of exceptions reaches the maximum allowed, a simple greedy approach to generate good reductions for a given planning domain, and a compilation scheme that generates MDP reductions from a PPDDL description of a planning problem.

Prevalence and Precursors of the use of Restraint and Seclusion in a Private Psychiatric Hospital: Comparison of Child and Adolescent Patients

The use of restraint and seclusion is highly regulated in psychiatric inpatient settings. However, the majority of studies of restraint and seclusion are based on public hospitals serving adult patients, with some limited data available on adolescents and children. This paper presents prospectively collected data on restraint and seclusion over a 2-year period at a private psychiatric hospital whose patients include large numbers of both adolescents and pre-adolescent children. 2years of restraint and seclusion data were analyzed on a total of 2,411 unique patients. Types of seclusion included in-room seclusion on the treatment unit and off-unit seclusion in a separate seclusion annex. Restraints consisted solely of short term (<15min) and longer term (>14min) manual restraints. The use of IM medication was also recorded. The precipitants of these events were examined. These included physical and verbal threats, stabbing or throwing objects, attempts to elope, attempts to hurt one's self or another, or property destruction. Out of 2,411 child and adolescent in-patients admitted during the period under review, only 703 (29%) experienced restraint or seclusion. Among these, the modal number of events per patient was one (n=156), but the maximum number of occurrences was 163. Child patients had a much higher frequency of events (n=396, 53%) than adolescents (n=307, 19%). There were notable differences in the types of seclusion events, with children typically experiencing in-room seclusion on the unit. When age was examined as a continuous variable, younger patients had a higher prevalence of restraint and seclusion, significantly more restraint and seclusion, and these restraint and seclusion events were significantly shorter than those seen in older patients. Multiple other potential determinants of these events were examined, including diagnosis, symptom severity at admission, age, and gender, but none of these predicted these events. Restraint and seclusion events were more common for children and less so for adolescents, with robust age effects for the likelihood of any seclusions, the number of seclusions and restraints, and the duration of seclusions and restraints. Patients who experienced restraint or seclusion typically required it only once during their hospitalization. Only age was found to be a predictor of the restraint and seclusion variables. Given these findings, it appears that management of agitated behavior in children and adolescents may be a qualitatively different phenomenon. Future research should be directed at understanding the determinants of high frequency agitated behavior and developing alternatives to seclusion or restraint.

Computational Complexity of Simultaneous Elementary Matching Problems

The simultaneous elementary E-matching problem for an equational theory E is to decide whether there is an E-matcher for a given system of equations in which the only nonconstant function symbols occurring in the terms to be matched are the ones constrained by the equational axioms of E. We study the computational complexity of simultaneous elementary matching problems for the equational theories A of semigroups, AC of commutative semigroups, and ACU of commutative monoids. In each case, we delineate the boundary between NP-completeness and solvability in polynomial time by considering two parameters, the number of equations in the systems and the number of constant symbols in the signature. Moreover, we analyze further the intractable cases of simultaneous elementary AC-matching and ACU-matching by also taking into account the maximum number of occurrences of each variable. Using combinatorial optimization techniques, we show that if each variable is restricted to having at most two occurrences, then several cases of simultaneous elementary AC-matching and ACU-matching can be solved in polynomial time.

On the covering radius of binary, linear codes meeting the Griesmer bound

Let g(k, d) = \sum_{i=0}^{k-1} \lceil d / 2^{i} \rceil . By the Griesmer bound, n \geq g(k, d) for any binary, linear [n, k, d] code. Let s = \lceil d / 2^{k-1} \rceil . Then, s can be interpreted as the maximum number of occurrences of a column in the generator matrix of any code with parameters [g(k, d), k, d] . Let \rho be the covering radius of a [g(k, d), k, d] code. It will be shown that \rho \leq d - \lceil s / 2 \rceil . Moreover, the existence of a [g(k, d), k, d] code with \rho = d - \lceil s / 2 \rceil is equivalent to the existence of a [g(k + 1, d), k + 1, d] code. For s \leq 2 , all [g(k,d),k,d] codes with \rho = d - \lceil s / 2 \rceil are described, while for s > 2 a sufficient condition for their existence is formulated.