scholarly journals Dynamic Virtual Network Reconfiguration Method for Hybrid Multiple Failures Based on Weighted Relative Entropy

Entropy ◽  
2018 ◽  
Vol 20 (9) ◽  
pp. 711 ◽  
Author(s):  
Yuze Su ◽  
Xiangru Meng ◽  
Qiaoyan Kang ◽  
Xiaoyang Han
Keyword(s):  
Relative Entropy ◽  
Virtual Network ◽  
Network Reconfiguration ◽  
Ranking Algorithm ◽  
Virtual Networks ◽  
Virtual Node ◽  
Multiple Failures ◽  
Linear Programming Formulation ◽  
Migration Method ◽  
Integer Linear Programming Formulation

Network virtualization can offer more flexibility and better manageability for next generation Internet. With the increasing deployments of virtual networks in military and commercial networks, a major challenge is to ensure virtual network survivability against hybrid multiple failures. In this paper, we study the problem of recovering virtual networks affected by hybrid multiple failures in substrate networks and provide an integer linear programming formulation to solve it. We propose a heuristic algorithm to tackle the complexity of the integer linear programming formulation, which includes a faulty virtual network reconfiguration ranking method based on weighted relative entropy, a hybrid multiple failures ranking algorithm, and a virtual node migration method based on weighted relative entropy. In the faulty virtual network reconfiguration ranking method based on weighted relative entropy and virtual node migration method based on weighted relative entropy, multiple ranking indicators are combined in a suitable way based on weighted relative entropy. In the hybrid multiple failures ranking algorithm, the virtual node and its connective virtual links are re-embedded, firstly. Evaluation results show that our heuristic method not only has the best acceptance ratio and normal operation ratio, but also achieves the highest long-term average revenue to cost ratio compared with other virtual network reconfiguration methods.

scholarly journals Multi-Agent Path Finding with Deadlines

2018 ◽  
Author(s):  
Hang Ma ◽  
Glenn Wagner ◽  
Ariel Felner ◽  
Jiaoyang Li ◽  
T. K. Satish Kumar ◽  
...  
Keyword(s):  
Flow Problem ◽  
Search Algorithms ◽  
The Other ◽  
Path Finding ◽  
Combinatorial Search ◽  
Programming Formulation ◽  
Commodity Flow ◽  
Linear Programming Formulation ◽  
Multi Agent ◽  
Integer Linear Programming Formulation

We formalize Multi-Agent Path Finding with Deadlines (MAPF-DL). The objective is to maximize the number of agents that can reach their given goal vertices from their given start vertices within the deadline, without colliding with each other. We first show that MAPF-DL is NP-hard to solve optimally. We then present two classes of optimal algorithms, one based on a reduction of MAPF-DL to a flow problem and a subsequent compact integer linear programming formulation of the resulting reduced abstracted multi-commodity flow network and the other one based on novel combinatorial search algorithms. Our empirical results demonstrate that these MAPF-DL solvers scale well and each one dominates the other ones in different scenarios.

scholarly journals Tournaments as Feedback Arc Sets

10.37236/1214 ◽  
1995 ◽  
Vol 2 (1) ◽  
Author(s):  
Garth Isaak
Keyword(s):  
Linear Programming ◽  
Lower Bounds ◽  
Integer Linear Programming ◽  
Minimum Size ◽  
Programming Formulation ◽  
Binary Expansion ◽  
Feedback Arc Set ◽  
Disjoint Cycles ◽  
Linear Programming Formulation ◽  
Integer Linear Programming Formulation

We examine the size $s(n)$ of a smallest tournament having the arcs of an acyclic tournament on $n$ vertices as a minimum feedback arc set. Using an integer linear programming formulation we obtain lower bounds $s(n) \geq 3n - 2 - \lfloor \log_2 n \rfloor$ or $s(n) \geq 3n - 1 - \lfloor \log_2 n \rfloor$, depending on the binary expansion of $n$. When $n = 2^k - 2^t$ we show that the bounds are tight with $s(n) = 3n - 2 - \lfloor \log_2 n \rfloor$. One view of this problem is that if the 'teams' in a tournament are ranked to minimize inconsistencies there is some tournament with $s(n)$ 'teams' in which $n$ are ranked wrong. We will also pose some questions about conditions on feedback arc sets, motivated by our proofs, which ensure equality between the maximum number of arc disjoint cycles and the minimum size of a feedback arc set in a tournament.

scholarly journals VIRTUAL NETWORK AS THE TECHNOLOGICAL LAYER OF THE PUBLIC SPACE AND ITS EFFECTS ON URBAN SPACES

2021 ◽  
Vol 11 (1) ◽  
pp. 182-194
Author(s):  
Merve KAYA ◽  
Özlem KANDEMİR
Keyword(s):  
Public Space ◽  
Information And Communication Technologies ◽  
Urban Areas ◽  
Communication Technologies ◽  
Virtual Network ◽  
Public Realm ◽  
Virtual Networks ◽  
The Public ◽  
Information And Communication ◽  
Physical Spaces

The physical and representational contents of the public space are in a dynamic evolving state with the changes in the social structure and urban structure. In the historical process, the phenomenon of public space has been affected by the developments experienced with the change in the way individuals establish relationships in public life. Today, this transformation has occurred through virtual networks with the development of information and communication technologies. The paper aims to understand the public sphere dynamics that have changed with information and communication technologies. Accordingly, it limits its scope on these questions: How virtual networks affect the representational form of public space? What are the spatial structuring of this new representational public realm? What effect does this transformation have on urban areas that are the physical spaces of public realm? The method of the study is to explain theoretical discussions by supporting examples. In this context, it has been found that virtual networks, known as a new form of public space, transform the representative and physical form of the public space in a multifaceted manner by relocating the way individuals communicate with each other on a virtual layer. In this virtual transformation, it has been seen that the representative public space is now formed on social networks and platforms and the spatial structuring of these areas is defined as virtual network. The effect of virtual networks on the physical spaces of the public realm is possible by clustering data about urban areas in these virtual environments. Therefore, the visibility of virtual networks on the physical spaces of the publicity takes place through the understanding of space usage; moreover, virtual network data, which hybridizes with contemporary urban areas, reveals new qualities in the sense of the city by embodying it through maps. The physical transformation of the public space with information and communication technologies is made possible by the use of virtual network data in the design processes of this new sensory city.

The Cloud Inside the Network

2015 ◽  
pp. 2198-2224
Author(s):  
João Soares ◽  
Romeu Monteiro ◽  
Márcio Melo ◽  
Susana Sargento ◽  
Jorge Carapinha
Keyword(s):  
Cloud Service ◽  
Integrated Approach ◽  
Cloud Services ◽  
Programming Formulation ◽  
Network Resources ◽  
Major Drawback ◽  
Linear Programming Formulation ◽  
Different Levels ◽  
Integer Linear Programming Formulation ◽  
Cloud Resources

The access infrastructure to the cloud is usually a major drawback that limits the uptake of cloud services. Attention has turned to rethinking a new architectural deployment of the overall cloud service delivery. In this chapter, the authors argue that it is not sufficient to integrate the cloud domain with the operator's network domain based on the current models. They envision a full integration of cloud and network, where cloud resources are no longer confined to a data center but are spread throughout the network and owned by the network operator. In such an environment, challenges arise at different levels, such as in resource management, where both cloud and network resources need to be managed in an integrated approach. The authors particularly address the resource allocation problem through joint virtualization of network and cloud resources by studying and comparing an Integer Linear Programming formulation and a heuristic algorithm.

Knowledge Integration through Strategic Alliances and Virtual Networks

2011 ◽  
pp. 591-600
Author(s):  
César Camisón ◽  
Beatriz Forés ◽  
María Eugenia Fabra
Keyword(s):  
Strategic Alliances ◽  
Information Technologies ◽  
Knowledge Integration ◽  
Virtual Network ◽  
High Tech ◽  
Second Phase ◽  
Virtual Networks ◽  
Knowledge Based ◽  
Sources Of Knowledge ◽  
Cooperative Agreements

According to the Knowledge-Based View, knowledge integration is one of the main capabilities that organizations must possess in today’s markets. In some high-tech industries, especially sciencebased industries such as biotechnology that need to integrate different bases of specialized expertise, the sources of knowledge are spread across a great variety of organizations. Strategic alliances are an option that may solve problems of speed or cost in these cases. Hence, in this chapter we identify advantages that inter-organizational cooperative agreements may have in the creation of knowledge, with a special emphasis on the case of strategic alliances in which the main aim is the joint creation of knowledge between partners and not simply the appropriation of this knowledge by one of the members of the agreement. In a second phase, we argue that virtual networks add more advantages to this type of alliance because of their special features. We define the virtual network as a strategic, temporary agreement between organizations that collaborate and coordinate their work through information technologies. This dimension adds greater flexibility to strategic alliances. We identify a virtual network typology by analyzing their properties and their value for the integration of knowledge.

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