Local Cyber-physical Attack with Leveraging Detection in Smart Grid

A well-designed attack in the power system can cause an initial failure and then results in large-scale cascade failure. Several works have discussed power system attack through false data injection, line-maintaining attack, and line-removing attack. However, the existing methods need to continuously attack the system for a long time, and, unfortunately, the performance cannot be guaranteed if the system states vary. To overcome this issue, we consider a new type of attack strategy called combinational attack which masks a line-outage at one position but misleads the control center on line outage at another position. Therefore, the topology information in the control center is interfered by our attack. We also offer a procedure of selecting the vulnerable lines of its kind. The proposed method can effectively and continuously deceive the control center in identifying the actual position of line-outage. The system under attack will be exposed to increasing risks as the attack continuously. Simulation results validate the efficiency of the proposed attack strategy.Comment: Accepted by IEEE SmartGridComm 201

Local Cyber-Physical Attack for Masking Line Outage and Topology Attack in Smart Grid

Malicious attacks in the power system can eventually result in a large-scale cascade failure if not attended on time. These attacks, which are traditionally classified into \emph{physical} and \emph{cyber attacks}, can be avoided by using the latest and advanced detection mechanisms. However, a new threat called \emph{cyber-physical attacks} which jointly target both the physical and cyber layers of the system to interfere the operations of the power grid is more malicious as compared with the traditional attacks. In this paper, we propose a new cyber-physical attack strategy where the transmission line is first physically disconnected, and then the line-outage event is masked, such that the control center is misled into detecting as an obvious line outage at a different position in the local area of the power system. Therefore, the topology information in the control center is interfered by our attack. We also propose a novel procedure for selecting vulnerable lines, and analyze the observability of our proposed framework. Our proposed method can effectively and continuously deceive the control center into detecting fake line-outage positions, and thereby increase the chance of cascade failure because the attention is given to the fake outage. The simulation results validate the efficiency of our proposed attack strategy.Comment: accepted by IEEE Transactions on Smart Grid. arXiv admin note: text overlap with arXiv:1708.0320

The Malaysian Medication Adherence Scale (MALMAS): Concurrent Validity Using a Clinical Measure among People with Type 2 Diabetes in Malaysia.

Medication non-adherence is a prevalent problem worldwide but up to today, no gold standard is available to assess such behavior. This study was to evaluate the psychometric properties, particularly the concurrent validity of the English version of the Malaysian Medication Adherence Scale (MALMAS) among people with type 2 diabetes in Malaysia. Individuals with type 2 diabetes, aged 21 years and above, using at least one anti-diabetes agent and could communicate in English were recruited. The MALMAS was compared with the 8-item Morisky Medication Adherence Scale (MMAS-8) to assess its convergent validity while concurrent validity was evaluated based on the levels of glycated hemoglobin (HbA1C). Participants answered the MALMAS twice: at baseline and 4 weeks later. The study involved 136 participants. The MALMAS achieved acceptable internal consistency (Cronbach's alpha=0.565) and stable reliability as the test-retest scores showed fair correlation (Spearman's rho=0.412). The MALMAS has good correlation with the MMAS-8 (Spearman's rho=0.715). Participants who were adherent to their anti-diabetes medications had significantly lower median HbA1C values than those who were non-adherence (7.90 versus 8.55%, p=0.032). The odds of participants who were adherent to their medications achieving good glycemic control was 3.36 times (95% confidence interval: 1.09-10.37) of those who were non-adherence. This confirms the concurrent validity of the MALMAS. The sensitivity of the MALMAS was 88.9% while its specificity was 29.6%. The findings of this study further substantiates the reliability and validity of the MALMAS, in particular its concurrent validity and sensitivity for assessing medication adherence of people with type 2 diabetes in Malaysia

Investigation of Structure-Function Relationships of Supported Metal Catalysts for the Aldehyde-Water-Shift Reaction

The conversion of biomass into fuels and chemicals is considered as sustainable alternatives of non-renewable fossil fuel and petroleum. Given the high water content in biomass, biomass conversion with water has also drawn increasing attention. The present research investigates the aldehyde water shift (AWS) reaction as a model reaction, in which acetaldehyde is oxidized by water and converted into acetic acid and hydrogen. Inspired by cascade catalytic systems reported for homogeneous catalysts and the bifunctional mechanism reported for the water gas shift reaction, we proposed that high AWS activities could be achieved for catalysts with highly dispersed sites for water dissociation and aldehyde oxidation that are in close proximity. With the hypothesis, we designed a series of oxide- and molybdenum carbide-supported metal catalysts and examined their physical/chemical properties and reactivity, aiming to understand the structure-function relationship. The respective roles of the support and the admetal in AWS, characters of active sites, and kinetic models are also elucidated. In the research, catalysts were prepared via incipient wetness impregnation and wet impregnation. Physisorption/chemisorption, x-ray diffraction, temperature programmed desorption, and other experiments were implemented to access the structural and surface characteristics. For oxide-supported metal catalysts, we highlight the importance of support reducibility and admetal selection. Supported Cu catalysts had ~4 times higher areal rate than those for supported Pt and Au catalysts. The combination of Cu and ceria yielded the highest AWS activity, and had a turnover frequency that was 8-fold higher than that for the bulk Cu. For the mix-phase molybdenum carbide-based catalysts, the bare carbide outperformed oxide supported Cu catalysts with a 2-fold or higher AWS rates, and its activity was enhanced by 100% upon 1.0ML Cu deposition. When increasing the Cu loading on the carbide, AWS rates of Cu predicted by the perimeter model agreed well with the experimental results. This suggests that Cu-carbide interfacial sites play a key role in catalyzing the reaction. These results of ceria and carbide supported Cu catalysts are consistent with the bifunctional mechanism hypothesis, in which water dissociation on the reducible oxide and carbide support is coupled with aldehyde oxidation on Cu admetal. The structure of carbide was also determined to be important to its reactivity. The hexagonal carbide showed a ~130% higher AWS rate than that of the cubic carbide. For all carbide based catalysts, the AWS reaction appeared to be limited by the surface reaction between the adsorbed water and adsorbed acetaldehyde. As metal oxide and carbide-based catalysts showed significant differences in selectivity, characteristics driving the selectivity were also investigated. For oxide-based catalysts, crotonaldehyde was produced as the major side product via aldol condensation. The rates of aldol condensation were found to correlate well with the weak acid site densities, implying that acid sites can be responsible for the crotonaldehyde formation. For carbide-based catalysts, ethanol produced via Cannizzaro reaction was found to be the major side product. The rates of Cannizzaro reaction were a strong function of acid site densities of carbide catalysts, indicating that the Cannizzaro reaction could be catalyzed by acid sites. This research establishes a groundwork for using supported metal catalyst and will help guide the development of future AWS catalysts.PHDChemical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/149853/1/weichung_1.pd

Controlled Heterogeneous Nucleation and Growth of Germanium Quantum Dots on Nanopatterned Silicon Dioxide and Silicon Nitride Substrates

Controlled heterogeneous nucleation and growth of Ge quantum dots (QDs) are demonstrated on SiO_2/Si_3N_4 substrates by means of a novel fabrication process of thermally oxidizing nanopatterned SiGe layers. The otherwise random self-assembly process for QDs is shown to be strongly influenced by the nanopatterning in determining both the location and size of the QDs. Ostwald ripening processes are observed under further annealing at the oxidation temperature. Both nanopattern oxidation and Ostwald ripening offer additional mechanisms for lithography for controlling the size and placement of the QDs

The Effects Between Numerical Tabulations And Graphs Of Financial Information On The Judgment Of Investors

Due to developments in information markets and advancements in information technology, and with the rapidity of information flow on the Internet, it is vital to increase the level of information transparency. Disclosure methods of financial information have presently become an important topic of discussion. By using numerical tables, non-distorted graphs or distorted graphs of financial information, this research discusses whether financial information display types indeed influence investors’ judgments and decisions. We investigate and analyze the use of graph disclosure in Taiwan and use experiment design methods to test the effect of investors’ judgment by comparing different display types of financial information. Our results find graphs are used to display comparative than numerical financial information, showing how this can influence investors’ awareness and judgments and use of graphs can be used to manipulate impressions (impression management)

Topological and organizational properties of the products of house-keeping and tissue-specific genes in protein-protein interaction networks

<p>Abstract</p> <p>Background</p> <p>Human cells of various tissue types differ greatly in morphology despite having the same set of genetic information. Some genes are expressed in all cell types to perform house-keeping functions, while some are selectively expressed to perform tissue-specific functions. In this study, we wished to elucidate how proteins encoded by human house-keeping genes and tissue-specific genes are organized in human protein-protein interaction networks. We constructed protein-protein interaction networks for different tissue types using two gene expression datasets and one protein-protein interaction database. We then calculated three network indices of topological importance, the degree, closeness, and betweenness centralities, to measure the network position of proteins encoded by house-keeping and tissue-specific genes, and quantified their local connectivity structure.</p> <p>Results</p> <p>Compared to a random selection of proteins, house-keeping gene-encoded proteins tended to have a greater number of directly interacting neighbors and occupy network positions in several shortest paths of interaction between protein pairs, whereas tissue-specific gene-encoded proteins did not. In addition, house-keeping gene-encoded proteins tended to connect with other house-keeping gene-encoded proteins in all tissue types, whereas tissue-specific gene-encoded proteins also tended to connect with other tissue-specific gene-encoded proteins, but only in approximately half of the tissue types examined.</p> <p>Conclusion</p> <p>Our analysis showed that house-keeping gene-encoded proteins tend to occupy important network positions, while those encoded by tissue-specific genes do not. The biological implications of our findings were discussed and we proposed a hypothesis regarding how cells organize their protein tools in protein-protein interaction networks. Our results led us to speculate that house-keeping gene-encoded proteins might form a core in human protein-protein interaction networks, while clusters of tissue-specific gene-encoded proteins are attached to the core at more peripheral positions of the networks.</p