101 research outputs found
Type-2 Fuzzy Single and Multi-Objective Optimisation Systems for Telecommunication Capacity Planning
Capacity planning in the telecommunications industry aims to maximise the effectiveness of implemented bandwidth equipment whilst allowing for equipment to be upgraded without a loss of service. The better implemented hardware can be configured, the better the service provided to the consumers can be. Additionally, the easier it is to rearrange that existing hardware with minimum loss of service to the consumer, the easier it is to remove older equipment and replace it with newer more effect equipment. The newer equipment can provide more bandwidth whilst consuming less power and producing less heat, lowering the overall operating costs and carbon footprint of a large scale network.
Resilient routing is the idea of providing multiple independent non-intersecting routes between two locations within a graph. For telecommunications organisations this can be used to reduce the downtime faced by consumers if there is a fault within a network. It can also be used to provide assurances to customers that rely on a network connection such as: financial institutions or government agencies.
This thesis looks at capacity planning within telecommunications with the aspiration of creating a set of optimisation systems that can rearrange data exchange hardware to maximise their performance with minimal cost and minimising downtime while allowing adaptations to an exchange’s configuration in order to perform upgrades.
The proposed systems were developed with data from British Telecom (BT) and are either deployed or are planned to be in the near future. In many cases the data used is confidential, but when this is the case an equivalent open source data set has been used for transparency.
As a result of this thesis the Heated Stack (HS) algorithm was created which has been shown to outperform the popular and successful NSGA-II algorithm by up to 92 % and NSGA-III by up to 69% at general optimisation tasks. HS also outperforms NSGA-II in 100% of the physical capacity planning experiments run and NSGA-II in 68% of the physical capacity planning experiments run. Additionally, as a result of this thesis the N-Non-Intersecting-Routing algorithm was shown to outperform Dijkstra’s algorithm by up to 38% at resilient routing. Finally, a new method of performing configuration planning through backwards induction with Monte Carlo Tree Search was proposed
A Heated Stack based Type-2 Fuzzy Multi-Objective Optimisation System for Telecommunications Capacity Planning
In this paper, we present the Heated Stack Algorithm (HS) which is a population based multi-objective evolutionary algorithm with temperature based on type-2 fuzzy logic meta-heuristic. Temperature plays a vital role in HS being used for two distinct procedures; Sorting and Crossover. In sorting, temperature is combined with the niche distance to determine the rank order of a population front. In crossover, the temperature of two population members are compared to determine the quantity of information to take from each parent. HS is a new optimisation algorithm capable of solving constrained real-world problems. This paper will present the HS application to a real-world capacity planning problem involving networking infrastructure. To proof the algorithm applicability to wider set of problems, we will report the HS results over a subset of the constrained multi objective problems used for optimisation competitions by the IEEE Congress on Evolutionary Computation (CEEC). In these problems we have compared to the popular NSGA-II and its successor NSGA-III. By use of the hyper-volume indicator, we find that the HS outperforms NSGA-II in 84% of cases, and outperforms NSGA-III in 69% of the cases
An Analysis of Tropical Transport: Influence of the Quasi-biennial Oscillation
An analysis of over 4 years of Upper Atmosphere Research Satellite (UARS) measurements of CH4, HF, O3, and zonal wind are used to study the influence of the quasi-biennial oscillation (QBO) on constituent transport in the tropics. At the equator, spectral analysis of the Halogen Occultation Experiment (HALOE) and Microwave Limb Sounder (MLS) observations reveals QBO signals in constituent and temperature fields at altitudes between 20 and 45 km. Between these altitudes, the location of the maximum QBO amplitude roughly corresponds with the location of the largest vertical gradient in the constituent field. Thus, at 40 km where CH4 and HF have strong vertical gradients, QBO signals are correspondingly large, while at lower altitudes where the vertical gradients are weak, so are the QBO variations. Similarly, ozone, which is largely under dynamical control below 30 km in the tropics, has a strong QBO signal in the region of sharp vertical gradients (∼28 km) below the ozone peak. Above 35 km, annual and semi-annual variations are also found to be important components of the variability of long-lived tracers. Therefore, above 30 km, the variability in CH4 and HF at the equator is represented by a combination of semiannual, annual, and QBO timescales. A one-dimensional vertical transport model is used to further investigate the influence of annual and QBO variations on tropical constituent fields. QBO-induced vertical motions are calculated from observed high resolution Doppler imager (HRDI) zonal winds at the equator, while the mean annually varying tropical ascent rate is obtained from the Goddard two-dimensional model. Model simulations of tropical CH4 confirm the importance of both the annual cycle and the QBO in describing the HALOE CH4 observations above 30 km. Estimates of the tropical ascent rate and the variation due to the annual cycle and QBO are also discussed
POSIWID and determinism in design for behaviour change
Copyright @ 2012 Social Services Research GroupWhen designing to influence behaviour for social or environmental benefit, does designers' intent matter? Or are the effects on behaviour more important, regardless of the intent involved? This brief paper explores -- in the context of design for behaviour change -- some treatments of design, intentionality, purpose and responsibility from a variety of fields, including Stafford Beer's "The purpose of a system is what it does" and Maurice Broady's perspective on determinism. The paper attempts to extract useful implications for designers working on behaviour-related problems, in terms of analytical or reflective questions to ask during the design process
Positive effects of tree diversity on tropical forest restoration in a field-scale experiment
Acknowledgments We thank all SEARPP research assistants and other collaborators for the help in establishing and maintaining the Sabah Biodiversity Experiment. We acknowledge assistance and support from SEARRP, Sabah Forestry Department, and the Leverhulme Trust—the Leverhulme Centre for Nature Recovery (A.H). Sabah Biodiversity Experiment data collection and maintenance was supported by Agencia Estatal de Investigación de España. This is Sabah Biodiversity Experiment publication 25. Funding: This work was supported by Natural Environment Research Council grants NE/S007474/1 (R.V.), NE/K016253/1 (A.H., S.B., D.F.R.P.B., and G.R.), and NE/X000281/1 (A.H. and D.F.R.P.B.); Comunidad de Madrid Atracción de Talento Modalidad I Fellowship 2018-T1/AMB-11095 (MJO); Agencia Estatal de Investigación de España (Ramon y Cajal, RYC2021-032049-I) (MJO); University of Zurich Research Priority Program on Global Change and Biodiversity (B.S.); and National Natural Science Foundation of China grant 42101407 (J.W.).Peer reviewedPublisher PD
Positive effects of tree diversity on tropical forest restoration in a field-scale experiment
Experiments under controlled conditions have established that ecosystem functioning is generally positively related to levels of biodiversity, but it is unclear how widespread these effects are in real-world settings and whether they can be harnessed for ecosystem restoration. We used remote-sensing data from the first decade of a long-term, field-scale tropical restoration experiment initiated in 2002 to test how the diversity of planted trees affected recovery of a 500-ha area of selectively logged forest measured using multiple sources of satellite data. Replanting using species-rich mixtures of tree seedlings with higher phylogenetic and functional diversity accelerated restoration of remotely sensed estimates of aboveground biomass, canopy cover, and leaf area index. Our results are consistent with a positive relationship between biodiversity and ecosystem functioning in the lowland dipterocarp rainforests of SE Asia and demonstrate that using diverse mixtures of species can enhance their initial recovery after logging
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The Implementation of Suspension and Expulsion Programs in Two Ontario School Boards
In 2008, the Ontario Ministry of Education made it mandatory that school boards in the province institute programs to serve suspended and expelled youth. These programs have now been in place for five years. Limited information has been collected as to how effective they are in addressing the needs of these students and little is known about the factors that have had an effect on the implementation of these policies. This study provides a description of the programs and focuses on the factors that have impacted policy implementation in this area. Research has shown that several factors impact policy implementation in general. Among the main influential factors are the impact of policy actors, the conditions that exist, supports that are available and the level and type of central control that is in place. Through one-on-one interviews involving thirteen school and board personnel in two Ontario school boards, this research explored how these four factors had an impact on the policy implementation process as it relates to the suspension and expulsion programs. The study participants believed that the relationships within and between these four factors and the creativity and flexibility this allowed were important in their ability to implement the new policies. Collaborative relationships between school board personnel and their community partners were highlighted in both participating boards as encouraging policy implementation. Strong relationships between staff, the students, and their families were important in finding program solutions for the particular conditions that existed, especially in the rural board that participated in the study. The importance of strong relationships between board personnel and community partners was also stressed, especially in the board that had a combined urban and rural make-up. Two-way communication between board and Ministry personnel allowed for the provision of appropriate supports in order to keep the programs viable. I conclude that when it comes to implementing new policies, central control from the Ministry should demonstrate an understanding of the distinct situations that exist in each board, the importance of key relationships, and the need for flexibility in allowing for creative responses to the needs that exist.Ed.D
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