A Logistic Growth Model for Software Reliability Estimation Considering Uncertain Factors

Software reliability growth models (SRGMs) are widely used to estimate software reliability by analyzing failure dataset throughout the testing process. A large number of SRGMs have been proposed on a regular basis by researchers since the 1970s. They are represented with a set of assumptions and a set of parameters. One major problem in SRGMs is that the uncertainties surrounding the assumptions and parameters are generally not taken into account by most of them. Therefore, sometimes, the predicted reliability on testing phase significantly varies in actual operational phase. This paper presents a logistic growth model that incorporates a special parameter to consider the effects of all possible uncertainties. A systematic analysis is carried out to identify the major uncertain factors and their impacts on the fault detection rate. The applicability of the model is shown by validating it on two different real datasets that are commonly used in various studies. The comparisons with nine established models in terms of mean square error (MSE), variance, predictive-ratio risk (PRR), [Formula: see text]and AIC have been presented.

Dynamics at Infinity and Existence of Singularly Degenerate Heteroclinic Cycles in Maxwell–Bloch System

In this paper, global dynamics of the Maxwell–Bloch system is discussed. First, the complete description of its dynamic behavior on the sphere at infinity is presented by using the Poincaré compactification in R3. Second, the existence of singularly degenerate heteroclinic cycles is investigated. It is proved that for a suitable choice of the parameters, there is an infinite set of singularly degenerate heteroclinic cycles in Maxwell–Bloch system. Specially, the chaotic attractors are found nearby singularly degenerate heteroclinic cycles in Maxwell–Bloch system by combining theoretical and numerical analyses for a special parameter value. It is hoped that these theoretical and numerical value results are given a contribution in an understanding of the physical essence for chaos in the Maxwell–Bloch system.

Optimising dividends and consumption under an exponential CIR as a discount factor

We consider an economic agent (a household or an insurance company) modelling its surplus process by a deterministic process or by a Brownian motion with drift. The goal is to maximise the expected discounted spending/dividend payments under a discounting factor given by an exponential CIR process. In the deterministic case, we are able to find explicit expressions for the optimal strategy and the value function. For the Brownian motion case, we are able to show that for a special parameter choice the optimal strategy is a constant-barrier strategy.

Meteor communication network in the monitoring system for technical means of navigation safety of the northern sea route

Изложены возможности и особенности использования в Арктической зоне России сети метеорной связи, которую целесообразно применить в целях обеспечения безопасности функционирования объектов транспортной инфраструктуры Северного морского пути, что способствует повышению экономической эффективности в целом всего морского транспортно-технологического процесса, а также для обеспечения безопасности судоходства в указанном регионе с учетом специфики распространения УКВ-радиосигналов и больших расстояний между объектами. Представлена временная диаграмма, характеризующая процесс функционирования радиолинии метеорной связи, соответственно, для оценки прерывистости связи предлагается использовать специальный параметр под названием коэффициент использования радиолинии. Показано, что для обеспечения энергетического контакта необходимой длительности между удаленными ведущими и ведомыми станциями метеорной связи в качестве пассивного ретранслятора может насыщенный метеорный след, способный обеспечить требуемую устойчивую связь, удовлетворяющей заданным требованиям по защите информации и по вероятности ошибочного приема ложных знаков с сохранением целостности сообщений при условии прерывистости энергетических контактов между корреспондентами. This paper describes the possibilities and features of using the meteor communication network in the Arctic zone of Russia. It is advisable to use this meteor communication network in order to ensure the safety of the transport infrastructure of the Northern sea route. This contributes to the overall economic efficiency of the entire Maritime transport and technological process. Also, it is appropriate to ensure the safety of navigation in the region, taking into account the specifics of the propagation of VHF radio signals and long distances between the objects. A timing diagram characterizing the operation of the meteor radio link is presented, so it is proposed to use a special parameter called the radio link utilization factor to estimate communication discontinuity. It has been shown that a saturated meteor trail can be used as a passive repeater to provide energy contact of the desired duration between the remote leading and trailing meteor communication stations. This is capable to provide the required stable communication that meets the specified data protection requirements. And it is also urgent for the probability of erroneous false signs reception with preservation of messages integrity under condition of energy contacts discontinuity between correspondents.

Normal waves in the electromagnetic metachiral isotropic medium with losses

Plane electromagnetic waves in an isotropic absorbing chiral medium (chiral metamaterial) are considered. A system of constitutive Drude - Born - Fedorov relations with complex values of the dielectric permittivity, magnetic permeability, and the chirality parameter is used. A distinction is made between forward and backward normal waves by introducing a special parameter - the wave type identifier. Analytical expressions for real and imaginary parts of wave numbers of homogeneous normal waves are presented.

A Novel and Secure Image Encryption Scheme Based on Chaotic Logistic Map and Random Scrambling using a Special Parameter of Gray Code Transformation

Result: The performance and security of the proposed algorithm have been analyzed on different evaluation metrics like MSE, PSNR, UAIC and NPCR and Correlation Coefficient etc. The experimental results show that the proposed algorithm is secure and provides better results from the XOR-based substitution method. Method: We suggest a new algorithm that improves the security of image encryption based on (n, k, p) gray code and bit plane decomposition method. This new encryption technique uses the bit plane decomposition of (n, k, p) gray code then random scrambling of each bit plane and chaotic logistic by map using pixel substitution method. Objective: A secure image encryption algorithm is proposed based on the combination of (n, k, p) gray code and chaotic logistic map to improve the performance of decomposition encryption methods. Background: Image security is a major concern in digital communication media. So there are so many algorithms symmetric and asymmetric are available for securely transmit the image. In a symmetric key algorithm, many algorithms are available based on bit plane decomposition and random scrambling using chaotic maps. Conclusion: This new method can be utilized in imaging systems like tomography images of medical field, telemedicine and digital video, video conferencing in communication system. Further, we will study to enhance and examine the execution of (n, k, p) gray code for data hiding and picture de-noising.

Methods of Moment and Maximum Entropy for Solving Nonlinear Expectation

In this paper, we consider a special nonlinear expectation problem on the special parameter space and give a necessary and sufficient condition for the existence of the solution. Meanwhile, we generalize the necessary and sufficient condition to the two-dimensional moment problem. Moreover, we use the maximum entropy method to carry out a kind of concrete solution and analyze the convergence for the maximum entropy solution. Numerical experiments are presented to compute the maximum entropy density functions.

The Influence of Problem Specific Neighborhood Structures in Metaheuristics Performance

Metaheuristics (MH) aptitude to move past local optimums makes them an attractive technique to approach complex computational problems, such as the Travelling Salesman Problem (TSP), but there is lack of information on the parameterization procedure and the appropriate parameters to improve MHs’ performance. In this paper the parameterization procedure of Simulated Annealing (SA) and Discrete Artificial Bee Colony (DABC) is addressed, with a focus on the Neighborhood Structure (NS). Numerous NS have been proposed for specific problems, which seem to indicate that the NS is a special parameter, whose optimization is independent of other parameters. The performance of eight NS was examined with SA and DABC under two optimization constraints, regarding computational time variation, to determine if there is one appropriate NS for the TSP problem, independent of the rest of the parameters of the optimization procedure. The computational study carried out for comparing the evaluation of the NS, including a statistical analysis, demonstrated a nonproportional increase in the performance of DABC with some NS. For SA the improvement of the solutions appeared to be more uniform with an almost nonexistent variance in improvement.

Development of a retrospective process for analyzing results of a HMM based posture recognition system in a functionalized nursing bed

In the area of care in general but especially in the care of elderly, there is a great interest in deriving patient parameters preparation free. For this purpose, a load cell functionalized nursing bed has been developed at Niederrhein University of Applied Science. The system allows analysis and recognition of the persons’ positions and actions in the bed. The Hidden Markov Toolkit (HTK) based posture recognition system was initially presented at the BMT 2015 by our research group. The initial system shows good results but to draw conclusions about the patient's condition, a minimum possible error rate should be achieved. For this purpose, a two-step retrospective analysis of the initial results was developed as an extension to improve the accuracy of the system.In a first step, the results of the initial recognition are analysed and classified into correct or incorrect results. This is done by means of probability based distance measure. The distances are calculated by the Viterbi algorithm. Based on these distance measures, errors and so called ‘secure support points’ are determined in the recognition result and the associated parameters are extracted.The second part of the extension deals with a retrospective recognition method to improve the error rate of the initial recognition step. Based on the determined support points, the errors are analysed again applying syntactic relation. To this end, a special parameter set to control the recognition system, the so-called ‘syntax’, is generated individually for each erroneous recognition result based on the preceding secure support point. The new parameterized recognition system is then used to improve the initial erroneous results by re-classification. Finally, the corrected recognition results are combined with the preliminary recognition result.