1,720,966 research outputs found
Vulnerability Analysis of Evacuation Transportation Networks
No full textAs natural disasters are increasing in frequency and scale, there is increasing interest in determining appropriate reactions to the disasters, such as evacuation planning and disaster relief distribution. When an evacuation network is built, strategic analyses are needed to support its operations. One of these is a vulnerability analysis to determine the weak points of an evacuation transportation network is one of those. This study aims to analyze the vulnerability of evacuation transportation networks constructed using the cell transmission model. Previous studies have considered all the possible scenarios to investigate weak points without using mathematical approaches. In this paper, we propose a bi-level optimization model to identify the fragile spots in a network. Due to the complexity of the problem, a genetic algorithm combined with linear programming is developed to find good solutions in a reasonable computational time. Solutions from the proposed algorithm are compared with optimal solutions.
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A Sequential Search Method of Dispatching Rules for Scheduling of LCD Manufacturing Systems
No full textA combination of dispatching rules to determine a sequence of jobs is often used for the scheduling of liquid crystal display or semiconductor manufacturing systems. Fab engineers determine weights ranging between 0 and 1 for dispatching rules, and the dispatching rules assign a value from 0 to 1 for each job. Then the weight given by the engineers and the value from each dispatching rule are multiplied and added for all rules, and the job that has the largest weighted sum is chosen to be processed on an idle machine. Hence, the weights of dispatching rules significantly affect the performance of fabs and should be determined carefully. This article proposes a sequential search method for finding a proper set of weights for dispatching rules to improve an objective value of the fab, such as increasing throughput or decreasing setup times. We use a decision tree approach and a hierarchical clustering method to efficiently search for weights in a short period of time by eliminating some sub-spaces that are less likely to have good objective values. The proposed method finds better weight sets than a random search method and a response optimization method in experiments.
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Persistent photoconductivity in Hf–In–Zn–O thin film transistors
No full textPassivated Hf-In-Zn-O (HIZO) thin film transistors suffer from a negative threshold voltage shift under visible light stress due to persistent photoconductivity (PPC). Ionization of oxygen vacancy sites is identified as the origin of the PPC following observations of its temperature-and wavelength-dependence. This is further corroborated by the photoluminescence spectrum of the HIZO. We also show that the gate voltage can control the decay of PPC in the dark, giving rise to a memory action. (C) 2010 American Institute of Physics. [doi:10.1063/1.3496029]
Instability in threshold voltage and subthreshold behavior in Hf–In–Zn–O thin film transistors induced by bias-and light-stress
No full textElectrical bias and light stressing followed by natural recovery of amorphous hafnium-indium-zinc-oxide (HIZO) thin film transistors with a silicon oxide/nitride dielectric stack reveals defect density changes, charge trapping and persistent photoconductivity (PPC). In the absence of light, the polarity of bias stress controls the magnitude and direction of the threshold voltage shift (Delta V(T)), while under light stress, V(T) consistently shifts negatively. In all cases, there was no significant change in field-effect mobility. Light stress gives rise to a PPC with wavelength-dependent recovery on time scale of days. We observe that the PPC becomes more pronounced at shorter wavelengths. (C) 2010 American Institute of Physics. [doi:10.1063/1.3480547]
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
- …
