196 research outputs found

    Weighted triangular and circular graph products for configuration processing

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    In this paper new weighted triangular and circular graph products are presented for configuring the new forms of structural models. The graph products are extensively used in graph theory and combinatorial optimization, however, the weighted triangular products defined in this paper are more suitable for the formation of practical space structural models which are impossible to generate by the previous products. Here, the weighted triangular and circular products are employed for the configuration processing of space structures that are of triangular shapes or a combination of triangular and rectangular shapes and also of the solid circler shapes as domes and some space structural models. The covered graph products are represented for selecting or eliminating some parts or panels from the product graph by using the second weights for the nodes of the generators. Cut out products are other new types of graph products which are defined to eliminate all of the connected elements to a specified node, to configure the model or grid with some vacant panels inside of the model. This application can easily be extended to the formation of finite element models

    Optimal Design of Jacket Supporting Structures for Offshore Wind Turbines Using CBO and ECBO Algorithms

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    Structural optimization of offshore wind turbines is a tedious task due to the complexity of the problem. However, in this article, this problem is tackled using two meta-heuristic algorithms - Colliding Bodies Optimization (CBO) and its enhanced version (ECBO) - for a jacket supporting structure. The OC4 reference jacket is chosen as a case study to validate the methods utilized in this research. The jacket supporting structure is modeled in MATLAB and its optimal design is performed while both Ultimate Limit State (ULS) and frequency constraints are considered. In the present study, it is presumed that both wind and wave phenomena act in the same horizontal direction. As a result, all resultant forces and moments will act in-plane and the substructure can therefore be modeled in 2D space. Considerable weight reduction is obtained during the optimization process while fulfilling all constraints.&nbsp

    Dry Eye Syndrome

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    Our understanding of keratoconjunctivitis sicca (KCS), also known as dry eye syndrome, has been changed over recent years. Until lately, the condition was thought to be merely due to aqueous tear insufficiency. Today, it is understood that KCS is a multifactorial disorder due to inflammation of the ocular surface and lacrimal gland, neurotrophic deficiency and meibomian gland dysfunction. This change in paradigm has led to the development of new and more effective medications

    DWTCP: Ultra Low Latency Congestion Control Protocol for Data Centers

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    Congestion control algorithms rely on a variety of congestion signals (packet loss, Explicit Congestion Notification, delay, etc.) to achieve fast convergence, high utilization, and fairness among flows. A key limitation of these congestion signals is that they are either late in feedback or they incur significant overheads. An ideal congestion control must discover any available bandwidth in the network, detect congestion as soon as link utilization approaches full capacity, and react timely to avoid queuing and packet drops, without significant overheads. To this end, this work proposes Scout service that leverages priority queues to infer bandwidth availability and link busyness at the host. The key observation here is that as the high priority queue (HPQ) gets busier, the low priority queue (LPQ) is served less. Therefore, the state of the link can be observed from the LPQ and any congestion can be detected several RTTs earlier than observing the HPQ. We propose a new transport protocol, Double-Window Transmission Control Protocol (DWTCP) that builds upon the Scout service to dynamically adjust its congestion window. Our testbed and simulation-based evaluation demonstrates that Scout enables a data center transport to achieve high throughput, near-zero queues, lower latency, and high fairness.Comment: 19 pages, 17 figure

    Appraising Mahallat Geothermal Region using thermal surveying data accompanied by the geological, geochemical and gravity analyses

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    Mahallat Geothermal Region, located in the central part of Iran, is known as one of the largest lowtemperature geothermal fields. In this study, Mahallat geothermal resource has been evaluated based on integrated geological, geochemical and geophysical analyses. Gravity data revealed three major negative anomaly zones. Based on the geochemical analyses, quartz geothermometers are more reliable than others and confirmed that the reservoir is about 90 °C. Lithological properties of Jurassic layers and high sulphate content observed in geochemical data showed traces of the coalrich layers on the hot fluids. Measured temperatures in 7 boreholes with the depths ranging from 50 to 100 m, have proposed that expected geothermal gradient will be about 81.5 °C/km. Among all drilled boreholes, the data coming from only one resulted in this almost reliable gradient. Other boreholes are clearly too shallow or affected by upflow or downflow of water along existing faults. Geological, geochemical, gravity and measurements of drilled boreholes suggested the existence of a shallow reservoir with an approximate temperature of 90 °C. Regarding gravity and observed faults, geothermal reservoir is elongated parallel to one of the main faults of the region with NE-SW strike

    Developing strategies to reduce the risk of hazardous materials transportation in Iran using the method of fuzzy swot analysis

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    An increase in hazardous materials transportation in Iran along with the industrial development and increase of resulted deadly accidents necessitate the development and implementation of some strategies to reduce these incidents. SWOT analysis is an efficient method for developing strategies, however, its structural problems, including a lack of prioritizing internal and external factors and inability to consider two sided factors reducing its performance in the situations where the number of internal and external factors affecting the risk of hazardous materials is relatively high and some factors are two sided in nature are presented in the article. Fuzzy SWOT analysis is a method the use of which helps with solving these problems and is the issue of employing an effective methodology. Also, the article compares the resulted strategies of the fuzzy method with the strategies developed following SWOT in order to show the relative supremacy of the new method. First published online: 27 Oct 201
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