Assessing reliability within error rate and time constraint for a stochastic node-imperfect computer network

2013 ◽  
Vol 227 (1) ◽  
pp. 80-85 ◽  
Author(s):  
Yi-Kuei Lin ◽  
Cheng-Fu Huang
Keyword(s):  
Network Topology ◽  
Error Rate ◽  
System Reliability ◽  
Computer Network ◽  
Performance Indicator ◽  
Real Life ◽  
Time Constraint ◽  
Quickest Path ◽  
Complete Failure ◽  
The Stability

In order to maintain the stability of a computer network, the assessment of system reliability is an important issue for the supervisor. A computer network can be modeled as a network topology with edges and nodes, in which each edge denotes a transmission line such as coaxial cables or fiber cables, and each node denotes a transmission station such as router or switch. For a real-life computer network, the capacity of each component (edge or node) should be stochastic owing to complete failure, partial failure, etc. Hence, the computer network with imperfect components is also stochastic and is named a stochastic node-imperfect computer network. Different from the quickest path problem considering deterministic capacity, this article concentrates on a stochastic node-imperfect computer network to evaluate the probability that d units of data can be transmitted within tolerable error rate and time constraint. Such a probability, called system reliability, is a performance indicator to provide to managers for further improvement. An efficient algorithm in terms of the approach of minimal paths to evaluate the system reliability is proposed.

scholarly journals Models and methods for local area network topology discovery with incomplete data

2021 ◽  
Vol 20 (1) ◽  
pp. 160-180
Author(s):  
Anton Andreev ◽  
Anton Shabaev
Keyword(s):  
Initial Data ◽  
Network Topology ◽  
Incomplete Data ◽  
Computer Network ◽  
Local Area Network ◽  
Real Life ◽  
Local Area ◽  
Area Network ◽  
Link Layer ◽  
Ambiguous Data

A lot of network management tasks require a description of the logical and physical computer network topology. Obtaining such a description in an automatic way is complicated due to the possibility of incompleteness and incorrectness of the initial data on the network structure. This article provides a study on the properties of incomplete initial data on network device connectivity on the link layer. Methods for generalized handling of the heterogeneous input data on the link layer are included. We describe models and methods for deriving a missing part of the data, as well as the condition in which it is possible to get a single correct network topology description. The article includes algorithms for building a link layer topology description from incomplete data when this data is possible to fulfill up to the required level. Also, we provide methods for detecting and resolving an ambiguity in the data and methods for improving incorrect initial data. Tests and evaluations provided in the article demonstrate the applicability and effectiveness of the build methods for discovering various heterogeneous real-life networks. Additionally, we show advantages of the provided methods over the previous analogs: our methods are able to derive up to 99\% data on link layer connectivity in polynomial time; able to provide a correct solution from an ambiguous data.

Mathematical Model for Cyber Attack in Computer Network

2017 ◽  
Vol 13 (1) ◽  
pp. 58-65 ◽  
Author(s):  
Yerra Shankar Rao ◽  
Aswin Kumar Rauta ◽  
Hemraj Saini ◽  
Tarini Charana Panda
Keyword(s):  
Computer Network ◽  
Real Life ◽  
Threshold Value ◽  
Malicious Code ◽  
Threshold Condition ◽  
Asymptotically Stable ◽  
Cyber Attack ◽  
Globally Asymptotically Stable ◽  
The Stability ◽  
Fifth Order

This investigation focuses to develop an e-SEIRS (susceptible, exposed, infectious, recovered) epidemic computer network model to study the transmission of malicious code in a computer network and derive the approximate threshold condition (basic reproduction number) to examine the equilibrium and stability of the model. The authors have simulated the results for various parameters used in the model and Runge-Kutta Fehlberg fourth-fifth order method is employed to solve system of equations developed. They have studied the stability of crime level to equilibrium and found the critical value of threshold value determining whether or not the infectious free equilibrium is globally asymptotically stable and endemic equilibrium is locally asymptotically stable. The simulation results using MATLAB agree with the real life situations.

scholarly journals Models and Methods for Discovery of Local Area Network Topology with Incomplete Data

2021 ◽  
Vol 20 (1) ◽  
pp. 68-93
Author(s):  
Andrey Aleshkin ◽  
Stanislav Balakirev ◽  
Valery Nevzorov ◽  
Pavel Savochkin
Keyword(s):  
Initial Data ◽  
Network Topology ◽  
Incomplete Data ◽  
Computer Network ◽  
Local Area Network ◽  
Real Life ◽  
Local Area ◽  
Area Network ◽  
Link Layer ◽  
Ambiguous Data

A lot of network  management tasks require a description of the logical and physical computer network topology. Obtaining such a description in an automatic way is complicated due to the possibility of incompleteness and incorrectness of the initial data on the network structure. This article provides  a study on the properties of incomplete initial data on network device connectivity on the link layer. Methods for generalized handling of the heterogeneous input data on the link layer are included. We describe models and methods for deriving  a missing part of the data, as well as the condition in which it is possible to get a single correct network topology description. The article includes algorithms for building a link layer topology description from incomplete data when this data is possible to fulfill up to the required level. Also, we provide methods for detecting and resolving an ambiguity in the data and methods for improving incorrect initial data. The tests and evaluations provided in the article demonstrate the applicability and effectiveness of the build methods for discovering  various heterogeneous real-life networks. Additionally,  we show the advantages of the provided methods over the previous analogs: our methods are able to derive up to 99% data on link layer connectivity in polynomial time; able to provide a correct solution from an ambiguous data.

scholarly journals Stability and Hopf Bifurcation in a Delayed SEIRS Worm Model in Computer Network

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Zizhen Zhang ◽  
Huizhong Yang
Keyword(s):  
Hopf Bifurcation ◽  
Computer Network ◽  
Sufficient Conditions ◽  
Positive Equilibrium ◽  
Normal Form Theory ◽  
Center Manifold Theorem ◽  
Local Hopf Bifurcation ◽  
Form Theory ◽  
Worm Model ◽  
The Stability

A delayed SEIRS epidemic model with vertical transmission in computer network is considered. Sufficient conditions for local stability of the positive equilibrium and existence of local Hopf bifurcation are obtained by analyzing distribution of the roots of the associated characteristic equation. Furthermore, the direction of the local Hopf bifurcation and the stability of the bifurcating periodic solutions are determined by using the normal form theory and center manifold theorem. Finally, a numerical example is presented to verify the theoretical analysis.

scholarly journals Pre-Drawn Syringes of Comirnaty for an Efficient COVID-19 Mass Vaccination: Demonstration of Stability

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1029
Author(s):  
Francesca Selmin ◽  
Umberto M. Musazzi ◽  
Silvia Franzè ◽  
Edoardo Scarpa ◽  
Loris Rizzello ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Real Life ◽  
Storage Conditions ◽  
Lipid Nanoparticles ◽  
Mass Vaccination ◽  
Hydrodynamic Diameter ◽  
The Us ◽  
Real Mass ◽  
The Stability ◽  
And Storage

Moving towards a real mass vaccination in the context of COVID-19, healthcare professionals are required to face some criticisms due to limited data on the stability of a mRNA-based vaccine (Pfizer-BioNTech COVID-19 Vaccine in the US or Comirnaty in EU) as a dose in a 1 mL-syringe. The stability of the lipid nanoparticles and the encapsulated mRNA was evaluated in a “real-life” scenario. Specifically, we investigated the effects of different storing materials (e.g., syringes vs. glass vials), as well as of temperature and mechanical stress on nucleic acid integrity, number, and particle size distribution of lipid nanoparticles. After 5 h in the syringe, lipid nanoparticles maintained the regular round shape, and the hydrodynamic diameter ranged between 80 and 100 nm with a relatively narrow polydispersity (<0.2). Samples were stable independently of syringe materials and storage conditions. Only strong mechanical stress (e.g., shaking) caused massive aggregation of lipid nanoparticles and mRNA degradation. These proof-of-concept experiments support the hypothesis that vaccine doses can be safely prepared in a dedicated area using an aseptic technique and transferred without affecting their stability.

Dynamic performance evaluation of multi – state systems under non – homogeneous continuous time Markov process degradation using lifetimes in terms of order statistics

2017 ◽  
Vol 231 (3) ◽  
pp. 255-264 ◽  
Author(s):  
Funda Iscioglu
Keyword(s):  
Markov Process ◽  
Order Statistics ◽  
Continuous Time ◽  
Dynamic Performance ◽  
Real Life ◽  
State Change ◽  
Transition Rates ◽  
Lifetime Analysis ◽  
Complete Failure ◽  
Effect Of Age

In multi-state modelling a system and its components have a range of performance levels from perfect functioning to complete failure. Such a modelling is more flexible to understand the behaviour of mechanical systems. To evaluate a system’s dynamic performance, lifetime analysis of a multi-state system has been considered in many research articles. The order statistics related analysis for the lifetime properties of multi-state k-out-of-n systems have recently been studied in the literature in case of homogeneous continuous time Markov process assumption. In this paper, we develop the reliability measures for multi-state k-out-of-n systems by assuming a non-homogeneous continuous time Markov process for the components which provides time dependent transition rates between states of the components. Therefore, we capture the effect of age on the state change of the components in the analysis which is typical of many systems and more practical to use in real life applications.

Open-Label Study of the Stability of Sublingual Nitroglycerin Tablets in Simulated Real-Life Conditions

2018 ◽  
Vol 122 (12) ◽  
pp. 2151-2156 ◽  
Author(s):  
James J. Nawarskas ◽  
Jason Koury ◽  
David A. Lauber ◽  
Linda A. Felton
Keyword(s):  
Real Life ◽  
Sublingual Nitroglycerin ◽  
Open Label ◽  
Open Label Study ◽  
Label Study ◽  
Life Conditions ◽  
The Stability

Stability Analysis of Supply Chain Cooperation Contract under Asymmetric Information

2010 ◽  
Vol 44-47 ◽  
pp. 794-798 ◽  
Author(s):  
Xin Ma
Keyword(s):  
Game Theory ◽  
Supply Chain ◽  
Repeated Games ◽  
Information Structure ◽  
Transition Period ◽  
Information Economics ◽  
Real Life ◽  
The Other ◽  
Game Equilibrium ◽  
The Stability

The stability of cooperation contract is the result of abandon opportunistic behavior in the process of repeated games among the enterprise and the other subjects in the supply chain from long-term interests, and is also the foundation of healthy development for the whole supply chain. But in real life cooperation contract instability everywhere for a variety of reasons, such as ethical considerations, institutional factors, cultural factors and special reasons during the transition period and so on. From the perspective of information economics and game theory, the main game process of cooperation between enterprise and the other subjects in supply chain is not only the game of information, but also the game of interests. Information structure and the interesting structure are the important factors for the subjects of the game of the implementation of decisions and the basic contractual constraints for cooperative game equilibrium. Cooperation behaviors among the enterprise and the other subjects in the supply chain were studied on the basis of game theory, and the stability of cooperation contract is also being discussed in this paper.

scholarly journals Managing cost uncertainties in transportation and assignment problems

1998 ◽  
Vol 2 (1) ◽  
pp. 65-104 ◽  
Author(s):  
V. Adlakha ◽  
H. Arsham
Keyword(s):  
Time Lag ◽  
Real Life ◽  
Optimal Solution ◽  
Global Market ◽  
Solution Algorithm ◽  
Assignment Problems ◽  
The Stability ◽  
Order Assignment ◽  
Cost Parameters ◽  
The Cost

In a fast changing global market, a manager is concerned with cost uncertainties of the cost matrix in transportation problems (TP) and assignment problems (AP).A time lag between the development and application of the model could cause cost parameters to assume different values when an optimal assignment is implemented. The manager might wish to determine the responsiveness of the current optimal solution to such uncertainties. A desirable tool is to construct a perturbation set (PS) of cost coeffcients which ensures the stability of an optimal solution under such uncertainties.The widely-used methods of solving the TP and AP are the stepping-stone (SS) method and the Hungarian method, respectively. Both methods fail to provide direct information to construct the needed PS. An added difficulty is that these problems might be highly pivotal degenerate. Therefore, the sensitivity results obtained via the available linear programming (LP) software might be misleading.We propose a unified pivotal solution algorithm for both TP and AP. The algorithm is free of pivotal degeneracy, which may cause cycling, and does not require any extra variables such as slack, surplus, or artificial variables used in dual and primal simplex. The algorithm permits higher-order assignment problems and side-constraints. Computational results comparing the proposed algorithm to the closely-related pivotal solution algorithm, the simplex, via the widely-used pack-age Lindo, are provided. The proposed algorithm has the advantage of being computationally practical, being easy to understand, and providing useful information for managers. The results empower the manager to assess and monitor various types of cost uncertainties encountered in real-life situations. Some illustrative numerical examples are also presented.

scholarly journals Versatile Dynamic Motion Generation Framework: Demonstration With a Crutch-Less Exoskeleton on Real-Life Obstacles at the Cybathlon 2020 With a Complete Paraplegic Person

2021 ◽  
Vol 8 ◽  
Author(s):  
Vaiyee Huynh ◽  
Guillaume Burger ◽  
Quoc Viet Dang ◽  
Raphaël Pelgé ◽  
Guilhem Boéris ◽  
...  
Keyword(s):  
Assistive Technology ◽  
Lower Limb ◽  
Real Life ◽  
Smartphone Application ◽  
Evolution System ◽  
Motion Generation ◽  
Motion Direction ◽  
Dynamic Motion ◽  
Direct Collocation ◽  
The Stability

Lower-limb exoskeletons are a promising option to increase the mobility of persons with leg impairments in a near future. However, it is still challenging for them to ensure the necessary stability and agility to face obstacles, particularly the variety that makes the urban environment. That is why most of the lower-limb exoskeletons must be used with crutches: the stability and agility features are deferred to the patient. Clinical experience shows that the use of crutches not only leads to shoulder pain and exhaustion, but also fully occupies the hands for daily tasks. In November 2020, Wandercraft presented Atalante Evolution, the first self-stabilized and crutch-less exoskeleton, to the powered exoskeleton race of the Cybathlon 2020 Global Edition. The Cybathlon aims at promoting research and development in the field of powered assistive technology to the public, contrary to the Paralympics where only participants with unpowered assistive technology are allowed. The race is designed to represent the challenges that a person could face every day in their environment: climbing stairs, walking through rough terrain, or descending ramps. Atalante Evolution is a 12 degree-of-freedom exoskeleton capable of moving dynamically with a complete paraplegic person. The challenge of this competition is to generate and execute new dynamic motions in a short time, to achieve different tasks. In this paper, an overview of Atalante Evolution system and of our framework for dynamic trajectory generation based on the direct collocation method will be presented. Next, the flexibility and efficiency of the dynamic motion generation framework are demonstrated by our tools developed for generating the important variety of stable motions required by the competition. A smartphone application has been developed to allow the pilot to choose between different modes and to control the motion direction according to the real situation to reach a destination. The advanced mechatronic design and the active cooperation of the pilot with the device will also be highlighted. As a result, Atalante Evolution allowed the pilot to complete four out of six obstacles, without crutches. Our developments lead to stable dynamic movements of the exoskeleton, hands-free walking, more natural stand-up and turning moves, and consequently a better physical condition of the pilot after the race compared to the challengers. The versatility and good results of these developments give hope that exoskeletons will soon be able to evolve in challenging everyday-life environments, allowing patients to live a normal life in complete autonomy.

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