Power Capacity of Transmission Lines (Case Study of Coaxial Cable)

The matrix of average power over frequency provided for each cable type is often used to evaluate the power capacity of transmission lines. There are two potential failure modes in cables also used to transmit high peak power. One is voltage breakdown; and the other is overheating. The major concern associated with application of peak power is breakdown due to high potential. In this paper, we have used coaxial cables as a case study to evaluate the power capacity of transmission lines. The study shows that the power capacity of transmission line also depends on the cable sizes and types and limited by voltage breakdown which occurs at a field strength of about Ed = 3x106V/m room temperature at sea level pressure.  In addition, if there are reflections on the line or guide, the power capacity is further reduced. It is believed that the power capacity of the transmission line can be increased by pressurizing the line with air or an inert gas, or by using a dielectric. Keywords: Impedance, Power Capacity, Transmission Line, Voltage Breakdown, Dielectric Strength

Disruption-Free Link Wake-up Optimisation for Energy Aware Networks

Part 1: Autonomic and Decentralized Management International audience Energy efficiency has become a major research topic in the Internet community as a result of unprecedented rise in the Information and Communication Technology (ICT) sector. One typical approach towards energy efficiency is to select a subset of IP routers or interfaces that will go to sleep mode during the off-peak period. However, on-the-fly network reconfiguration is generally deemed harmful especially to real time packets due to routing re-convergence. In this paper, we develop an efficient algorithm for achieving energy efficiency which is disruption free. The objective is to incrementally wake up sleeping links upon the detection of increased traffic demand. Unlike normal approaches of manipulating link weights or reverting to full topology in case of even minor network congestion and thereby sacrificing energy savings, our algorithm wakes up the minimum number of sleeping links to the network in order to handle this dynamicity. The performance of our algorithm was evaluated using the GEANT network topology and its traffic traces over a period of one week. According to our simulation results, up to almost 47% energy gains can be achieved without any obstruction to the network performance. Secondly, we show that the activation of a small number of sleeping links is still sufficient to cope with the observed traffic surge. Document type: Part of book or chapter of boo

Novel Power Management Technique for Energy-Efficient Cloud System Applications Using A Java Agent

The increasing growth in cloud service has also increased the power usage required to have excellent functionality and stable cloud services. Globally, there has been a massive growth in Internet activity and Internet users, which significantly impacts the cloud network’s power consumption rate. Therefore, having fundamental expertise in balancing the trade-off between cloud system performance and energy efficiency is the key to leveraging the cloud network’s alarming high power consumption rate. In this work, a mobile agent will be used to regulate the activities in data centre networks to minimise the energy usage rate at each runtime. Mobile agent technology is a powerful tool compatible with the distributive and adaptive cloud architectural design platform with a novel solution to its power usage excesses. Agents are empowered to switch-off switches/links that are inactive. Java agent was used to schedule and consolidate the servers and network activities. Our approach enhanced cloud resource utilisation and drastically increased power efficiency by reducing servers’ idle time

Green backbone routing.

Reducing energy consumption in the Telecom industry has become a major research challenge to the Internet community due to high level of energy waste on redundant network devices. In search for a paradigm shift, recent research efforts have been focusing on time-driven sleep-mode reconfiguration of network elements during periods of low traffic demand. However, due to the routing re-convergence issue of today's traditional IP routing protocols, frequent network reconfigurations are generally deemed to be harmful as a result of routing table re-convergence. Furthermore, diurnal traffic behaviours are unpredictable and can lead to network congestion as a result of the reduced network resources. This thesis presents novel event-driven green backbone routing schemes for network managements which are capable of saving energy in fixed IP networks (using both regular and non-regular traffic matrix) without inhibiting its performance. First, a Link Wake-up Optimisation Technique (LiWOT) is proposed during energy saving periods when the pruned topology is applied. The key novelty here is that LiWOT selects the minimum number of router's line cards to wake-up when the network is congestion is detected. This is contrary to the norms of reverting to the full network topology or on-the-fly network reconfigurations in the case of even minor traffic surge and thereby sacrificing energy savings. In order to mitigate the effect of routing re-convergence in networks, LiWOT prioritises the waking up of non-disruptive sleeping links. This scheme was further extended to a fully disruption-free scheme. The second proposed scheme is the Green Link Weight Disruption-Free Energy-aware Traffic Engineering which limits its wake-up operation to only non-disruptive links. In order to maximise the energy savings, the number of this type of links are maximised in an offline manner. Using a genetic algorithm based approach, a new link weight optimisation scheme is proposed and this forms the basis of the second research contribution. Finally, a completely dynamic link sleeping reconfigurations (DLSR) for green traffic engineering is proposed. The scheme coordinates the sleep and wake-up operations in a dynamic way such that operations are based on the current traffic. The key contribution is that DLSR is oblivious of historical traffic conditions like the previous schemes and can enhance energy savings by putting back woken-up links to sleeping mode during low traffic. The performances of the three schemes were evaluated using the publicly accessible traffic traces of both GEANT and Abilene network respectively over a period of one week and the obtained results show a substantial amount of energy saving

Using a simple expert system to assist a powered wheelchair user

A simple expert system is described that helps wheelchair users to drive their wheelchairs. The expert system takes data in from sensors and a joystick, identifies obstacles and then recommends a safe route. Wheelchair users were timed while driving around a variety of routes and using a joystick controlling their wheelchair via the simple expert system. Ultrasonic sensors are used to detect the obstacles. The simple expert system performed better than other recently published systems. In more difficult situations, wheelchair drivers did better when there was help from a sensor system. Wheelchair users completed routes with the sensors and expert system and results are compared with the same users driving without any assistance. The new systems show a significant improvement

Mobile Agent Based-Approach for Enhancing Energy Efficiency Cloud Data Center Network,

Cloud computing has become the bedrock of new, emerging smart technology. It has numerous benefits that encourage small, medium and large enterprises to use other technology through the internet. Despite the benefits of cloud technology, the challenge of the high power consumption rate it incurs as its leverages its promised attributes remains. This paper used mobile agent technology to solve the complexity problem in the data centre system, which happens to be the backbone of cloud technology. The mobile agent was embedded to both servers and switches to regulate their activities and then shut down underutilised components. Mobile agent (Java agent) is the first of its kind used on a cloud network. Our proposed approach saved a significant amount of energy and also improved the entire system performance during runtime