Measurement of SIFT operating system overhead

The overhead of the software implemented fault tolerance (SIFT) operating system was measured. Several versions of the operating system evolved. Each version represents different strategies employed to improve the measured performance. Three of these versions are analyzed. The internal data structures of the operating systems are discussed. The overhead of the SIFT operating system was found to be of two types: vote overhead and executive task overhead. Both types of overhead were found to be significant in all versions of the system. Improvements substantially reduced this overhead; even with these improvements, the operating system consumed well over 50% of the available processing time

Modular lightweight components for peripheral e-mobility solutions

Based on a comprehensive prototype, the researchers at the Otto von Guericke University systematically investigate components and system solutions within a project regarding the interplay of electric vehicles and range extenders. In consideration of the electric vehicle, named Editha, different operating strategies for the use of range extenders in the predominant application field of electric mobility were tested. The principal objectives of the project are to determine appropriate operating strategies for the use of a range extender and operating characteristics for an optimal system configuration of existing or future engine technology in combination with the respective generator technology. Thus, sensible and expedient combinatorics with regard to weight and performance criteria arises. This project aims at gaining an overall understanding of the interplay between automotive and alternative energy generation based on the prototype and the exemplary design of both power trains

Impact of residential energy system sizing and control over heat pump’s system cost and reliability

Using a simulation-based approach, this work analyses the impact that different energy unit sizes and control methodologies will have over the capital and running costs of an air source heat pump (ASHP) system to be installed in a refurbished dwelling. A total of 9 different heating configuration options were investigated and the cumulative cash flow over a period of 10 years (including initial investment) was utilized to compare the systems from a customer perspective. Additionally, in selected cases, the cycling of the heat pump was calculated in order to estimate the life-span of the device. The building and heat pump systems were simulated using TRNSYS energy system models. The results revealed the sensitivity of the system’s costs and life-span to its operating characteristics. For example, operating the system as a direct gas boiler replacement resulted in capital costs above £10,000 and the unit's life span reduced by half in comparison to more favourable operational strategies. The results highlight the fact that the successful technical and financial performance of heat pumps within the UK’s residential market will depend of designers, installers and end-users’ awareness regarding optimal operational strategies for this technology

‘Top 4’ strategies to mitigate targeted cyber intrusions: mandatory requirement explained

Introduction The Top 4 Strategies to Mitigate Targeted Cyber Intrusions (the Strategies) are the most effective security controls an organisation can implement at this point in time based on the our current visibility of the cyber threat environment. The Australian Signals Directorate (ASD), also known as the Defence Signals Directorate (DSD), assesses that implementing the Top 4 will mitigate at least 85% of the intrusion techniques that the Cyber Security Operations Centre (CSOC) responds to. For this reason, the Attorney‐General\u27s Department has updated the Australian Government Protective Security Policy Framework (PSPF) to require Australian government agencies to implement ICT protective security controls as detailed in the Australian Government Information Security Manual (ISM) to meet ASD\u27s Top 4 Strategies. Document scope This document provides specific implementation information on the Top 4 Strategies, including: information on the scope of and steps to manage the mandatory requirement; and some technical guidance for IT system administrators to planning and implementing the Top 4 Strategies in a typical Windows environment. This document focusses on implementing the Top 4 in a Windows environment, as the majority of government business is currently conducted using Windows operating systems. For agencies seeking implementation advice for systems that use other operating environments, ASD recommends seeking advice from your agency systems integrator or vendor in the first instance. Additionally, ASD recommends conducting research using open source publications, forums and resources available on the operating system and how each of the Top 4 could be implemented. If your agency finds it is not possible or feasible to implement the Top 4 in a non‐windows environment, you should follow appropriate risk‐management practices as outlined in the ISM

Hybrid HVDC for supply of power to offshore oil platforms

A HVDC hybrid system, comprising a line commutated thyristor HVDC converter and a STATCOM, is proposed in this paper for supplying power to offshore oil platforms that do not have their own generation. The proposed system combines the robust performance, low capital cost and low power loss of a line commutated HVDC converter, with the fast dynamic performance of an equivalent VSC Transmission system. The paper describes the principles and control strategies of the proposed system. PSCAD/EMTDC simulations are presented to demonstrate the robust performance of the system using case studies of various operating conditions such as black-start, load perturbations, AC fault conditions and disturbance caused by the starting of large local induction machines

Price Pooling and the Gains from Hedging: Application to a Swedish Grain Cooperative

Optimal hedging strategies are analyzed for a cooperative operating a price pooling system in the presence of price and quantity risk. A three-period model, accounting for default risk and storage, is developed. Hedging allows the cooperative to increase the pool price offered to farmers by 2.8 - 4% for moderate risk parameters.Agribusiness, Marketing,

Power electronics options for large wind farm integration : VSC-based HVDC transmission

This paper describes the use of voltage source converter based HVDC transmission (VSC transmission) system for grid integration of large wind farms over long distance. The wind farms can be based on either doubly-fed induction generator (DFIG) or fixed speed induction generator (FSIG). The paper describes the operation principles and control strategies of the proposed system. Automatic power balancing during network AC fault is achieved without communication between the two converters. PSCAD/EMTDC simulations are presented to demonstrate the robust performance and to validate the proposed system during various operating conditions such as variations of generation and AC fault conditions. The proposed VSC transmission system has technical and economic advantages over a conventional AC connection for integrating large wind farms over long distanc