Modeling and performance evaluation of stealthy false data injection attacks on smart grid in the presence of corrupted measurements

The false data injection (FDI) attack cannot be detected by the traditional anomaly detection techniques used in the energy system state estimators. In this paper, we demonstrate how FDI attacks can be constructed blindly, i.e., without system knowledge, including topological connectivity and line reactance information. Our analysis reveals that existing FDI attacks become detectable (consequently unsuccessful) by the state estimator if the data contains grossly corrupted measurements such as device malfunction and communication errors. The proposed sparse optimization based stealthy attacks construction strategy overcomes this limitation by separating the gross errors from the measurement matrix. Extensive theoretical modeling and experimental evaluation show that the proposed technique performs more stealthily (has less relative error) and efficiently (fast enough to maintain time requirement) compared to other methods on IEEE benchmark test systems.Comment: Keywords: Smart grid, False data injection, Blind attack, Principal component analysis (PCA), Journal of Computer and System Sciences, Elsevier, 201

Withstand or succumb: Christian universities and the implications of Obergefell v. Hodges

Most Christian universities support a traditional view of human sexuality. It is uncertain if they can survive with their religious identity intact, given the rapid increase in societal acceptance of same-sex marriage. The 2015 Obergefell v. Hodges decision legalizing same-sex marriage increases pressure to be more affirming. Thirty-four presidents at universities in the Council for Christian Colleges and Universities (CCCU) participated in a survey, and twelve were interviewed to explore their perceptions regarding that pressure and potential responses. The study was framed by institutional isomorphism theory, and data were analyzed using basic qualitative research methods. The results show that coercive isomorphism is the strongest mechanism, with current pressure to conform emanating from state and federal government. Regional variance is considerable as institutions in the South report little pressure while those in blue states like California report strong local pressure. It is experienced in actual or implied threats to remove student access to state and federal financial aid and eliminate tax-exempt status at universities that discriminate based on sexual orientation. Liberal voices within the Church, accrediting agencies, LGBT advocacy groups, and changing student values are other sources of pressure. Universities seek compromise solutions but are prepared to mount a legal challenge based on the Free Exercise Clause of the First Amendment. They are not prepared to deal with changing student values, the strongest long-term source of pressure. To withstand pressure to conform, Christian universities must craft a unified response; find alternative sources of funding; engage and educate their boards; and find a way to assure young people that it is possible to be kind and loving while holding non-affirming policies related to same-sex marriage

Accuracy assessment of Tri-plane B-mode ultrasound for non-invasive 3D kinematic analysis of knee joints

BACKGROUND Currently the clinical standard for measuring the motion of the bones in knee joints with sufficient precision involves implanting tantalum beads into the bones. These beads appear as high intensity features in radiographs and can be used for precise kinematic measurements. This procedure imposes a strong coupling between accuracy and invasiveness. In this paper, a tri-plane B-mode ultrasound (US) based non-invasive approach is proposed for use in kinematic analysis of knee joints in 3D space. METHODS The 3D analysis is performed using image processing procedures on the 2D US slices. The novelty of the proposed procedure and its applicability to the unconstrained 3D kinematic analysis of knee joints is outlined. An error analysis for establishing the method's feasibility is included for different artificial compositions of a knee joint phantom. Some in-vivo and in-vitro scans are presented to demonstrate that US scans reveal enough anatomical details, which further supports the experimental setup used using knee bone phantoms. RESULTS The error between the displacements measured by the registration of the US image slices and the true displacements of the respective slices measured using the precision mechanical stages on the experimental apparatus is evaluated for translation and rotation in two simulated environments. The mean and standard deviation of errors are shown in tabular form. This method provides an average measurement precision of less than 0.1 mm and 0.1 degrees, respectively. CONCLUSION In this paper, we have presented a novel non-invasive approach to measuring the motion of the bones in a knee using tri-plane B-mode ultrasound and image registration. In our study, the image registration method determines the position of bony landmarks relative to a B-mode ultrasound sensor array with sub-pixel accuracy. The advantages of our proposed system over previous techniques are that it is non-invasive, does not require the use of ionizing radiation and can be used conveniently if miniaturized.This work has been supported by School of Engineering & IT, UNSW Canberra, under Research Publication Fellowship

Evaluation of Ultrafiltration for Spacecraft Water Reuse

Ultrafiltration is examined for use as the first stage of a primary treatment process for spacecraft wastewater. It is hypothesized that ultrafiltration can effectively serve as pretreatment for a reverse osmosis system, removing the majority of organic material in a spacecraft wastewater. However, it is believed that the interaction between the membrane material and the surfactant found in the wastewater will have a significant impact on the fouling of the ultrafiltration membrane. In this study, five different ultrafiltration membrane materials are examined for the filtration of wastewater typical of that expected to be produced onboard the International Space Station. Membranes are used in an unstirred batch cell. Flux, organic carbon rejection, and recovery from fouling are measured. The results of this evaluation will be used to select the most promising membranes for further study

Electrification financing and tariffs: international literature review

This report was commissioned by the National Electrification Forum (NELF}. It is a review of international experience in electricity pricing, funding and financial management. The purpose of the report is to assess how these issues have affected electrification programmes in developing countries and to draw conclusions which will assist NELF in establishing appropriate electricity pricing and financing policies for South Africa. A successful electrification programme which enables widened access to electricity is ultimately dependent on the creation and maintenance of a financially viable electricity distribution industry. Financial viability is, in tum, crucially dependent on appropriate pricing and financing policies and financial management practices. The report is based on an extensive review of international literature. The review of electricity pricing commences with a discussion on pricing policies, the principles of economic efficiency and marginal cost-based prices. Some of the difficulties of this approach are highlighted, and additional, often more pressing, pricing objectives are noted, including the imperative of prices which will allow financial viability and prices which will achieve greater equity. Actual practice in developing countries is then examined with regard to tariff levels and structures. Tariff levels are compared with long run marginal costs, generally being much lower in developing countries. The tariff structures discussed include inclining block, single flat rate, two-part, unmetered and time-of-use tariffs. The question of subsidies is raised as well as the problems of implementing equitable life-line tariffs