Ant Colony Optimization For Survivable Virtual Topology Mapping In Optical Wdm Networks

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2009Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2009İnternet kullanımının her geçen gün biraz daha yaygınlaşması, bant genişliği problemini de beraberinde getirmiştir. Bu ihtiyacı karşılamak amacıyla, optik ağlarda WDM (dalga boyu bölmeli çoğullama – wavelength division multiplexing) teknolojisi kullanılarak fiber kabloların kapasitesi, her biri farklı dalga boyunda çalışan yüzlerce farklı iletim kanalına bölünmüştür. Paket iletimi yapan üst katmanların kullanacağı uçtan uca kurulan optik bağlantılara ışıkyolu denir. Ağda kurulan tüm ışıkyolları ağın sanal topolojisini oluşturur. Bir fiber üzerinde farklı dalga boylarında olmak koşuluyla birden fazla ışıkyolu yönlendirilebilir. Fakat bir fiberin herhangi bir şekilde hasara uğraması, üzerinden geçen bütün ışıkyollarının kopması sonucu ciddi boyutlarda veri kaybına neden olur. Bu durumdan korunma yöntemlerinden biri ışıkyollarının fiberler üzerinde hataya bağışık şekilde yönlendirilmesidir öyle ki fiziksel katmanda bir ya da daha fazla bağlantı koptuğunda sanal topoloji hala bağlı kalmalıdır. Bu çalışmanın amacı altı farklı karınca koloni algoritması kullanılarak fiberlerin kapasite kısıtlarını aşmadan ve ağ kaynaklarının kullanımını minimize edecek şekilde ışıkyollarını hataya bağışık olarak fiziksel topoloji üzerinde yönlendirmek ve algoritmaları başarım, hız ve ağ kaynaklarının etkin kullanımı açısından karşılaştırmaktır.As the internet use increases significantly in everyday life, the need for bandwidth increases accordingly. To meet this need, high capacity of fibers used in optical networks, can be divided into many channels, using the WDM technology. End-to-end optical connections that the packet layer (IP, Ethernet, etc.) uses are called lightpaths. All the lightpaths set up on the network form the virtual topology. A fiber is able to route more than one ligthpaths with different wavelengths. Any damage to a fiber causes all the channels routed through this link to be broken, which may result in a serious amount of data loss. As a solution to this problem, the virtual layer can be mapped onto the physical topology, such that, a failure on any physical link does not disconnect the virtual topology. This is known as the survivable virtual topology mapping problem. In this study, our aim is to compare the performance of six different ant colony algorithms in finding a survivable mapping of a given virtual topology while minimizing the used wavelength links and without violating the wavelength capacity of fibers in terms of success rates, speed and resource usage.Yüksek LisansM.Sc

ACODV : Ant Colony Optimisation Distance Vector routing in ad hoc networks

A mobile ad hoc network is a collection of wireless mobile devices which dynamically form a temporary network, without using any existing network infrastructure or centralised administration. Each node in the network effectively becomes a router, and forwards packets towards the packet’s destination node. Ad hoc networks are characterized by frequently changing network topology, multi-hop wireless connections and the need for dynamic, efficient routing protocols. The overarching requirement for low power consumption, as battery powered sensors may be required to operate for years without battery replacement; An emphasis on reliable communication as opposed to real-time communication, it is more important for packets to arrive reliably than to arrive quickly; and Very scarce processing and memory resources, as these sensors are often implemented on small low-power microprocessors. This work provides overviews of routing protocols in ad hoc networks, swarm intelligence, and swarm intelligence applied to ad hoc routing. Various mechanisms that are commonly encountered in ad hoc routing are experimentally evaluated under situations as close to real-life as possible. Where possible, enhancements to the mechanisms are suggested and evaluated. Finally, a routing protocol suitable for such low-power sensor networks is defined and benchmarked in various scenarios against the Ad hoc On-Demand Distance Vector (AODV) algorithm.Dissertation (MSc)--University of Pretoria, 2005.Computer ScienceUnrestricte

AN IMPROVED BARE-BONES PARTICLE SWARM ALGORITHM FOR MULTI-OBJECTIVE OPTIMIZATION WITH APPLICATION TO THE ENGINEERING STRUCTURES

In this paper, an improved bare-bones multi-objective particle swarm algorithm is proposed to solve the multi-objective size optimization problems with non-linearity and constraints in structural design and optimization. Firstly, the development of particle individual guide and the randomness of gravity factor are increased by modifying the updated form of particle position. Then, the combination of spatial grid density and congestion distance ranking is used to maintain the external archive, which is divided into two parts: feasible solution set and infeasible solution set. Next, the global best positions are determined by increasing the probability allocation strategy which varies with time. The algorithmic complexity is given and the performance of solution ability, convergence and constraint processing are analyzed through standard test functions and compared with other algorithms. Next, as a case study, a support frame of triangle track wheel is optimized by the BB-MOPSO and improved BB-MOPSO. The results show that the improved algorithm improves the cross-region exploration, optimal solution distribution and convergence of the bare-bones particle swarm optimization algorithm, which can effectively solve the multi-objective size optimization problem with non-linearity and constraints

Emergence in the security of protocols for mobile ad-hoc networks

This thesis is concerned with the study of secure wireless routing protocols, which have been deployed for the purpose of exchanging information in an adhoc networking enviromnent. A discrete event simulator is developed, utilising an adaptive systems modelling approach and emergence that aims to assess networking protocols in the presence of adversarial behaviour. The model is used in conjunction with the characteristics that routing protocols have and also a number of cryptographic primitives that can be deployed in order to safeguard the information being exchanged. It is shown that both adversarial behaviour, as well as protocol descriptions can be described in a way that allows for them to be treated as input on the machine level. Within the system, the output generated selects the fittest protocol design capable of withstanding one or more particular type of attacks. As a result, a number of new and improved protocol specifications are presented and benchmarked against conventional metrics, such as throughput, latency and delivery criteria. From this process, an architecture for designing wireless routing protocols based on a number of security criteria is presented, whereupon the decision of using particular characteristics in a specification has been passed onto the machine level

Emergence in the security of protocols for mobile ad-hoc networks

This thesis is concerned with the study of secure wireless routing protocols, which have been deployed for the purpose of exchanging information in an adhoc networking enviromnent. A discrete event simulator is developed, utilising an adaptive systems modelling approach and emergence that aims to assess networking protocols in the presence of adversarial behaviour. The model is used in conjunction with the characteristics that routing protocols have and also a number of cryptographic primitives that can be deployed in order to safeguard the information being exchanged. It is shown that both adversarial behaviour, as well as protocol descriptions can be described in a way that allows for them to be treated as input on the machine level. Within the system, the output generated selects the fittest protocol design capable of withstanding one or more particular type of attacks. As a result, a number of new and improved protocol specifications are presented and benchmarked against conventional metrics, such as throughput, latency and delivery criteria. From this process, an architecture for designing wireless routing protocols based on a number of security criteria is presented, whereupon the decision of using particular characteristics in a specification has been passed onto the machine level.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Fedco Seeds and Supplies 2020

When is a seed catalog more than a seed catalog? When it is the Fedco Seed catalog. Fedco, founded in 1978, is a worker-consumer cooperative in Maine known for promoting the ideals of cooperation, transparency, and the common ownership of seeds. These archives contain thousands of pages of Fedco’s seed catalogs. As one of its editors noted, “We give our readers things to think about.” Annual themes have included the role played by soil bacteria—the microscopic heroes that make life on this planet possible; the contributions of plant breeders and seed keepers; poetry by Walt Whitman, Vergil, and Russell Libby, among others. Editorials often stress the negative impact multinational corporations have on the genetic diversity of food crops, and provide annual updates on genetic engineering and the consolidation of the seed industry. Bits of humor are throughout, some of them in possibly the catalogs’ best feature: original art, and engravings from old seed catalogs and horticultural books. It is, in the words of Fedco’s founder CR Lawn, “More than a marketing tool.

Shortest Route at Dynamic Location with Node Combination-Dijkstra Algorithm

Abstract— Online transportation has become a basic requirement of the general public in support of all activities to go to work, school or vacation to the sights. Public transportation services compete to provide the best service so that consumers feel comfortable using the services offered, so that all activities are noticed, one of them is the search for the shortest route in picking the buyer or delivering to the destination. Node Combination method can minimize memory usage and this methode is more optimal when compared to A* and Ant Colony in the shortest route search like Dijkstra algorithm, but can’t store the history node that has been passed. Therefore, using node combination algorithm is very good in searching the shortest distance is not the shortest route. This paper is structured to modify the node combination algorithm to solve the problem of finding the shortest route at the dynamic location obtained from the transport fleet by displaying the nodes that have the shortest distance and will be implemented in the geographic information system in the form of map to facilitate the use of the system. Keywords— Shortest Path, Algorithm Dijkstra, Node Combination, Dynamic Location (key words