310,416 research outputs found
A comprehensive assessment of power system resilience to a hurricane using a two-stage analytical approach incorporating risk-based index
No full textSustainability of power systems is a vital need for modern societies. The occurrence of extreme weather events, such as hurricanes, may lead to blackouts. Hence, power systems resilience is a critical issue for experts. The main focus of this paper is on how to assess power system resilience comprehensively. In this regard, a two-stage framework is proposed. In the first stage, an approach is presented to evaluate power system resilience against a single intensity of a hurricane, which is called snapshot resilience assessment. The Cost of Energy Not Supplied (CENS) is regarded as a primary criterion. A risk measure called Conditional Value at Risk (CVaR) is incorporated into this approach to manage the risk of experiencing unfavorable failure scenarios. Accordingly, CVaR of CENS is proposed as an index in this stage. In the second stage, an approach for comprehensive resilience assessment is proposed, which is based on the trend of changing the values of snapshot resilience indices over a range of intensities of the event. The applicability of the proposed framework is tested in the IEEE 24-bus system. Finally, to examine the accuracy of the framework, the resilience of the test system is re-evaluated after applying a resilience improvement method
A self-adaptive modified backward forward sweep method: Application to dynamic flow direction changes
No full textIn recent years, distribution networks with the presence of new technologies have faced a significant evolving dynamic that challenges the use of traditional power flow calculations specifically backward-forward sweep (BFS). One of the most important effects of this evolving dynamics of distribution networks is related to the increase in the dynamic flow direction changes of the branches. In other words, there is a considerable gap between the practical application of BFS and its basic characteristics, which makes it impossible for practical application because BFS is not compatible with dynamic flow direction changes. Since BFS does not have complex mathematical and modeling concepts, bridging this gap is a meaningful necessity. Hence based on graph theory and the deep node concept, a self-adaptive modified backward-forward sweep (SAMBFS) is proposed so that BFS will be a practical application method for distribution networks. Finally, the application of SAMBFS for dynamic topology changes, P2P trade, several substations, and harmonic calculations as various concepts of the evolving dynamics of distribution networks are investigated
A novel resource allocation model based on the modularity concept for resiliency enhancement in electric distribution networks
No full textPaying attention to the modularity feature of electric distribution systems improves their performance against severe events and makes an outstanding opportunity for resiliency enhancement. In this paper, a novel framework based on the modularity concept is proposed in which, by deploying smart grid technologies and forming efficient modules, effective and robust energy in distribution systems is provided. Optimal placement of distributed generation (DG) resources, load control options, switching devices, and tie lines are simultaneously incorporated in the proposed linear allocation model. To consider electrical and topological characteristics in the independent functioning of the formed modules, a path-based method is employed. The effectiveness and computability of the proposed algorithm are examined by performing several simulations on two modified 37-bus and 84-bus test systems. The results demonstrate that the developed modular structure, by subdividing the system into several independent parts, creates more flexibility for the recovery process and facilitates the self-healing capabilities
Optimal Planning of Residential Energy Hubs Considering Customer Desire Function
No full textThis paper proposes an optimal residential energy hub (REH) design framework where the desired tradeoff between maximizing the satisfaction level of residential user energy usage and minimizing the overall costs is obtained by establishing a customer desire function (CDF). Considering the major household appliances, the REH demands are categorized into several groups, and CDFs are formulated and applied to each group of loads. The developed mathematical model results in a mixed-integer linear programming optimization problem. Simulations were carried out on a residential building as a case study. Numerical results confirmed the presented framework effectiveness in improving the end-user convenience level and enhancing the investment benefits. They also demonstrated the significance of various energy networks and the optimal configuration of REH components on the financial and technical of the REH
Thermal expansion anomalies of R(Fe, M)(12) (R=Y, Nd; M=Mo and Si)
No full textStructural and thermal-expansion anomaly studies on R(Fe,M)(12) (R=Nd and and Y, M=Mo and Si) compounds were performed by x-ray diffraction. Mo atoms occupy the 8i site. While Si atoms occupy the 8f and 8j sites but not the 8i site. Thermal-expansion anomaly shows only in ab plane in the Mo compounds, while becomes very weak and along with only the c axis in the Si compounds. The anomaly was attributed to the contribution of the interactions of short Fe-Fe distances similar to the previous explanation on other R-Fe intermetallics and that of other strongly positive interactions such as 8j-8j. (c) 2005 American Institute of Physics.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000230168300025&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Physics, AppliedSCI(E)EICPCI-S(ISTP)
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Letter from Thomas R. Bodine, American Friends Service Committee Seattle office, to Mary M. Kimber, May 25, 1942
No full textLetter from Thomas R. Bodine to Mary M. Kimber, asking Kimber to visit individuals from the Puget Sound area incarcerated at Pinedale Assembly Center: Rev. Daisuke Kitigawa, Waichi Oyanagi, Chisako Higuchi, Mutsuo Hasiguchi and Mrs. Matsuoka, Makato Kobukata, the Hirabayashi family, and Violet Yokoyama. A note in pencil at the top of the page: "Burcham." A response letter from Grace and Calvin Coke to Thomas R. Bodine is found in item: chs_ms840_0306.Personal correspondence, organizational records, government documents, publications, and other papers created or collected by Joseph R. Goodman documenting the forced removal and incarceration of Japanese Americans during World War II, as well as organized resistance to incarceration. Included in the collection are records of the Japanese Young Men's Christian Association and the Japanese American Citizens' League in San Francisco, including papers of the Japanese YMCA's executive secretary Lincoln Kanai; Sakai family papers; Goodman's correspondence to and from Japanese American incarcerees, organizations opposing forced removal and incarceration of Japanese Americans, the War Relocation Authority, and others; publications, photographs, and ephemera from the Topaz Relocation Center, where Goodman taught high school; War Relocation Authority records and publications; and newspaper clippings, pamphlets, and reports about forced removal and incarceration created by various government, religious, and civic organizations, in California and nationwide
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Liftings for noncomplete probability spaces
No full textThe current state of knowledge concerning liftings for noncomplete probability spaces is discussed. This is a somewhat expanded version of the author's talk given at the 1991 Summer Conference on General Topology and Applications in Honor of Mary Ellen Rudin and Her Work.PT: S; CR: BURKE MR, IN PRESS P AM MATH S BURKE MR, 1991, ISRAEL J MATH, V73, P33 BURKE MR, 1992, ISRAEL J MATH, V79, P289 CARLSON T, THEOREM LIFTING CHRISTENSEN JPR, 1974, TOPOLOGY BOREL STRUC FREMLIN DH, 1989, HDB BOOLEAN ALGEBRAS, P877 INOESCUTULCEA A, 1966, 5TH P BERK S MATH ST, V2 IONESCUTULCEA A, 1967, CONTRIBUTIONS PROB 1, P63 IONESCUTULCEA A, 1969, TOPICS THEORY LIFTIN JECH TJ, 1978, SET THEORY JOHNSON RA, 1980, P AM MATH SOC, V80, P234 JUST W, IN PRESS T AM MATH S KUPKA J, 1983, INDIANA U MATH J, V32, P717 LOSERT V, 1983, LNM, V1080, P95 MAHARAM D, 1958, P AM MATH SOC, V9, P987 SHELAH S, 1983, ISRAEL J MATH, V45, P90 TALAGRAND M, 1982, P AM MATH SOC, V84, P379 VONNEUMANN J, 1931, CRELLES J MATH, V165, P109; NR: 18; TC: 0; J9: ANN N Y ACAD SCI; PG: 4; GA: BZ86BSource type: Electronic(1
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