118,592 research outputs found
al- Ḥaraka at-taʿāwunīya fi 'l-Yaman wa-qaḍīyat at-tanmiya al-iqlīmīya
No full textProfessors World Peace Academy - Middle East. Muhammad Ahmad Al-Saidi (ed.)al-Ḥaraka at-taʿāwunīya fi 'l-Yaman wa-qaḍīyat at-tanmiya al-iqlīmīyaZsfassung in Arabisch. - Teilw. in arab. Schr., arab
SAIDI minimization of a remote distribution feeder
No full textAbstract Distribution system reliability assessment is an important part of distribution system operation and planning. This paper presents some approaches taken to minimize the SAIDI (System Average Interruption Duration Index) for a remote distribution feeder in an 11kV distribution system. Resulting from unavailability of alternative backup supplies from the other adjacent feeders, distributed generators (DG) can be used as backup supplies in this case. Coordinating distribution automation (DA) system with DG, the restoration area can be made larger and the outage time can be shorter, consequently, the distribution system reliability can be improved significantly. In this paper, factors affecting SAIDI are discussed and methods including feeder reconfiguration, recloser installation and replacement and DG installation are applied to minimize SAIDI. Comparative studies are performed and related results are addressed
Transformer le granit sans compromettre sa santé : caractérisation et contrôle de la poussière de silice émise par des opérations de polissage à sec et humide
No full textAli Bahloul, chercheur à l\u27IRSST et Mohamed Nejib Saidi, Chercheur postdoctoral à l\u27Université Concordia expliquent comment contrôler la dispersion des particules lors des opérations de polissage à sec ou par voie humide
Approaches of Setting SAIDI Target Value for Taiwan Power System
No full text[[abstract]]This paper presents a method for setting the annual target on customer’s electricity supply reliability for the regional transmission offices of Taiwan Power Company (Taipower). The reliability of customer’s electricity supply is measured by the System Average Interruption Duration Index (SAIDI) and the System Average Interruption Frequency Index (SAIFI) in Taipower. The analytic hierarchy process (AHP) has been adopted, by which all the influential factors on SAIDI and SAIFI can be presented into a hierarchical structure which describes how these factors affect the annual SAIDI (or SAIFI) level. The evaluation indices that measure the regional status of these influential factors are designed at the lowest layer of the hierarchical model. The relative weightings among the influential factors are derived from the linguistic comparison results obtained by the questionnaire survey conducted on the maintenance and operation engineers of Taipower’s 6 regional transmission offices. The evaluation index values of regional transmission offices are multiplied to the weighting of each influential factor from the lowest layer upwards until the objective values at the top of hierarchical structure are calculated. On basis of the relative comparison among these 6 objective values calculated, Taipower’s corporate SAIDI (or SAIFI) target is then distributed to be the 6 regional targets. To provide a further insight into the effectiveness and limitation of proposed method, the AHP results on Taipower’s corporate target distribution obtained from the calculation are compared with Taipower’s SAIDI records at 2003. The method after slight modification can be extended to other power engineering management target.[[fileno]]2030164030017[[department]]電機工程學
The Middle to Later Stone Age transition at Panga ya Saidi, in the tropical coastal forest of eastern Africa
Get PDFThe Middle to Later Stone Age transition is a critical period of human behavioral change that has been variously argued to pertain to the emergence of modern cognition, substantial population growth, and major dispersals of Homo sapiens within and beyond Africa. However, there is little consensus about when the transition occurred, the geographic patterning of its emergence, or even how it is manifested in the stone tool technology that is used to define it. Here, we examine a long sequence of lithic technological change at the cave site of Panga ya Saidi, Kenya, that spans the Middle and Later Stone Age and includes human occupations in each of the last five Marine Isotope Stages. In addition to the stone artifact technology, Panga ya Saidi preserves osseous and shell artifacts, enabling broader considerations of the covariation between different spheres of material culture. Several environmental proxies contextualize the artifactual record of human behavior at Panga ya Saidi. We compare technological change between the Middle and Later Stone Age with on-site paleoenvironmental manifestations of wider climatic fluctuations in the Late Pleistocene. The principal distinguishing feature of Middle from Later Stone Age technology at Panga ya Saidi is the preference for fine-grained stone, coupled with the creation of small flakes (miniaturization). Our review of the Middle to Later Stone Age transition elsewhere in eastern Africa and across the continent suggests that this broader distinction between the two periods is in fact widespread. We suggest that the Later Stone Age represents new short use-life and multicomponent ways of using stone tools, in which edge sharpness was prioritized over durability.1. Introduction 1.1. Identifying the MSA-LSA technological transition in eastern Africa 1.2. Site and environment 2. Materials and methods 3. Results 3.1. Local stone sources 3.2. Lithic materials, frequency, and size 3.3. Core reduction 3.4. Flakes 3.5. Retouched flakes 4. Discussion 4.1. The Panga ya Saidi lithic sequence in context 4.2. Overview of the Panga ya Saidi sequence 4.3. The MSA-LSA lithic transition in eastern Africa and beyond 5. Conclusion
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
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
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
Methods for Setting SAIDI Target for Regional Transmission Offices of Taipower
No full text[[abstract]]In recent years, Taiwan Power (Taipower) company has endeavored to implement various programs, in order to reduce customers’ power interruption duration and frequency, as part of the corporate operational goals. Since 2002, Taipower has set the corporate operational target for the yearly SAIDI (System Average Interruption Duration Index) and SAIFI (System Average Interruption Frequency Index), and then has distributed the corporate target to the regional transmission offices to serve as the regional management target.
The Methods for setting the targets, including how to distribute the corporate target to the regional offices, relied purely on the engineering and managerial experiences. No logical or any rational method has been adopted, which thus has led to the distribution of corporate target sometimes on an unfair basis. Due to the lack of automatic monitoring on power interruption, an over-expected, or sometimes unviable, target may adversely force the regional offices forge the field data, which can cause a significant depression on field engineers’ morale.
To resolve this difficulty, this thesis presents a method which can logically distribute the corporate target to the regional offices, serving as the regional managerial target. In the thesis, the SAIDI target has been adopted as an example to illustrate the methods, which include selecting a variety of influential factors on SAIDI and accounting these factors according to their relative impact on SAIDI in the design of corporate target distribution process or distribution formula.
The thesis focuses on the target setting for Taipower’s SAIDI due to the transmission system faults. The analytic hierarchy process (AHP) has been adopted, by which all the relation among influential factors on SAIDI can be presented into the hierarchical structure. The process begins with the model formulation by selection of influential factors on SAIDI and the formulation of factors into the modulized hierarchical model. At the second stage, the process then finds out 2 groups of parameters. One group refer to the evaluation indices which measure the regional status influential factors designed at the lowest layer of the hierarchical model, so to identify the disparity among Taipower’s 6 regional transmission offices.
The second group of parameters refer to the relative weights among the influential factors, which are derived from the linguistic comparison results obtained by the questionnaire survey conducted on Taipower’s maintenance and operation engineers of the 6 regional transmission offices. At the third stage of AHP, by combining these 2 groups of parameters, the process evaluates the evaluation index values to each influential factor from the lowest layer upwards until the objective value at the top of hierarchical structures is calculated.
At the final stage, Taipower’s corporate SAIDI target is distributed to be the 6 regional targets based on the relative comparison among the above 6 objective values.
To give a further insight into the numerical evaluation results, the AHP results on Taipower’s corporate target distribution have been compared with Taipower’s SAIDI record at 2003. In addition, the disparity on the questionnaire results among Taipower’s 6 regional offices as well as between the feeder and the substation departments of regional offices are analyzed to investigate the potential characteristics of designed model in future application.[[fileno]]2030164030027[[department]]電機工程學
Letter from unknown writer to Jesse L. Boyce
No full textLetter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County
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