22 research outputs found

    The structure of the semigroup of proper holomorphic mappings of a planar domain to the unit disc

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    Given a bounded n-connected domain in the plane bounded by non-intersecting Jordan curves, and given one point on each boundary curve, L. Bieberbach proved that there exists a proper holomorphic mapping of the domain onto the unit disc that is an n-to-one branched covering with the properties that it extends continuously to the boundary and maps each boundary curve one-to-one onto the unit circle, and it maps each given point on the boundary to the point 1 in the unit circle. We modify a proof by H. Grunsky of Bieberbach's result to show that there is a rational function of 2n+2 complex variables that generates all of these maps. We also show how to generate all the proper holomorphic mappings to the unit disc via the rational function.Comment: 17 page

    Weather-based interruption prediction in the smart grid utilizing chronological data

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    This unique study will demonstrate a combined effect of weather parameters on the total number of power distribution interruptions in a region. Based on common weather conditions, a theoretical model can predict interruptions and risk assessment with immediate weather conditions. Using daily and hourly weather data, the created models will predict the number of daily or by-shift interruptions. The weather and environmental conditions to be addressed will include rain, wind, temperature, lightning density, humidity, barometric pressure, snow and ice. Models will be developed to allow broad applications. Statistical and deterministic simulations of the models using the data collected will be conducted by employing existing software, and the results will be used to refine the models. Models developed in this study will be used to predict power interruptions in areas that can be readily monitored, thus validating the models. The application has resulted in defining the predicted number of interruptions in a region with a specific confidence level. Reliability is major concern for every utility. Prediction and timely action to minimize the outage duration improves reliability. Use of this predictor model with existing smart grid self-healing technology is proposed

    Screening of marigold (Tagetes erecta L.) cultivars for drought stress based on vegetative and physiological characteristics

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    Drought tolerance is an important genotypic character to be exploited for the plant cultivar selection under water deficit conditions. In the recent study, we examined the response of two marigold cultivars (Inca and Bonanza) under different regimes of drought stress. The aim was to determine the best performing cultivar under water/drought stress. Three irrigation treatments include; 4 days (T1), 6 days (T2) and 8 days (T3) in comparison to control 1 day (T0) interval were imposed. Response characters under study were morphological, physiological and anatomical. Complete Randomized Design (CRD) with four replications in two factorial arrangements was followed for experiment layout. The results revealed that increasing water stress adversely affect plant height, in both cultivars. Both cultivars showed a decreasing trend to the number of flowers under water stress. Total chlorophyll contents including a, b were also showed reduction under prolonged drought treatment in both cultivars from (2.7 mg g-1 FW) to (1 mg g-1 FW). Overall, the performance of cultivar (cv.) Inca was satisfactory under water stress regimes. These results are helpful for selecting drought tolerant marigold cultivars in water scarce areas.  Â

    The structure of proper holomorphic mappings of a planar domain onto a simply connected domain

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    It can be easily shown that all the proper one to one holomorphic functions from a bounded simply conncected domain onto the right half plane, such that a chosen point on the boundary gets mapped to infinity, are rational functions of the Riemann map on the domain and are also rational functions of the image of the boundary point under the Riemann map if the boundary point is allowed to vary. In this work, we have derived analogous results in case of a multiply connected planar domain and have shown that all the proper n to 1 holomorphic functions from an n-connected domain onto the right half plane, such that one point on each boundary component gets mapped to infinity, are rational functions of 2 Ahlfors maps and are also rational functions of the images of the chosen boundary points under the 2 Ahlfors maps if the boundary points are allowed to vary

    VHITS: Vertical handoff initiation and target selection in a heterogeneous wireless network

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    Global connectivity, for anyone, at anyplace, at anytime, to provide high-speed, high-quality, and reliable communication channels for mobile devices, is now becoming a reality. The credit mainly goes to the recent technological advances in wireless communications comprised of a wide range of technologies, services, and applications to fulfill the particular needs of end-users in different deployment scenarios (Wi-Fi, WiMAX, and 3G/4G cellular systems). In such a heterogeneous wireless environment, one of the key ingredients to provide efficient ubiquitous computing with guaranteed quality and continuity of service is the design of intelligent handoff algorithms. Traditional single-metric handoff decision algorithms, such as Received Signal Strength (RSS) based, are not efficient and intelligent enough to minimize the number of unnecessary handoffs, decision delays, and call-dropping and/or blocking probabilities. This research presented a novel approach for the design and implementation of a multi-criteria vertical handoff algorithm for heterogeneous wireless networks. Several parallel Fuzzy Logic Controllers were utilized in combination with different types of ranking algorithms and metric weighting schemes to implement two major modules: the first module estimated the necessity of handoff, and the other module was developed to select the best network as the target of handoff. Simulations based on different traffic classes, utilizing various types of wireless networks were carried out by implementing a wireless test-bed inspired by the concept of Rudimentary Network Emulator (RUNE). Simulation results indicated that the proposed scheme provided better performance in terms of minimizing the unnecessary handoffs, call dropping, and call blocking and handoff blocking probabilities. When subjected to Conversational traffic and compared against the RSS-based reference algorithm, the proposed scheme, utilizing the FTOPSIS ranking algorithm, was able to reduce the average outage probability of MSs moving with high speeds by 17%, new call blocking probability by 22%, the handoff blocking probability by 16%, and the average handoff rate by 40%. The significant reduction in the resulted handoff rate provides MS with efficient power consumption, and more available battery life. These percentages indicated a higher probability of guaranteed session continuity and quality of the currently utilized service, resulting in higher user satisfaction levels

    Vehicle to Pedestrian Systems: Survey, Challenges and Recent Trends

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    The accelerated rise of new technologies has reshaped the manufacturing industry of contemporary vehicles. Numerous technologies and applications have completely revolutionized the driving experience in terms of both safety and convenience. Although vehicles are now connected and equipped with a multitude of sensors and radars for collision avoidance, millions of people suffer serious accidents on the road, and unfortunately, the death rate is still on the rise. Collisions are still a dire reality for vehicles and pedestrians alike, which is why the improvement of collision prevention mechanisms is an ongoing necessity. Collision prevention mechanisms have evolved from vision-based systems like radars to systems that transcend the driver’s line of sight. These latter systems depend on vehicular ad hoc networks (VANETs) to employ bidirectional communication between vehicles and other vehicles (V2V) as well as between vehicles and road infrastructure (V2I). Recently, research has expanded to include a new communication system between vehicles and pedestrians (V2P) through the latter’s smartphones. In this paper, we provide an extensive survey of existing V2P projects, categorize different parameters that influence V2P system design, compare different communication technologies used in V2P systems and present an overview of recent trends that solve problems in V2P systems like network congestion, pedestrian localization, and context information exchange. The main contribution of our work is to pave the road for future research by providing a comprehensive view of projects, challenges and recent trends in the emerging and rapidly growing field of V2P system design

    Research Article A Fuzzy Preprocessing Module for Optimizing the Access Network Selection in Wireless Networks

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    Copyright © 2013 Faisal Kaleem et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. A heterogeneous wireless network is characterized by the presence of different wireless access technologies that coexist in an overlay fashion. These wireless access technologies usually differ in terms of their operating parameters. On the other hand, Mobile Stations (MSs) in a heterogeneous wireless network are equipped with multiple interfaces to access different types of services from these wireless access technologies. The ultimate goal of these heterogeneous wireless networks is to provide global connectivity with efficient ubiquitous computing to these MSs based on the Always Best Connected (ABC) principle. This is where the need for intelligent and efficient Vertical Handoffs (VHOs) between wireless technologies in a heterogeneous environment becomes apparent. This paper presents the design and implementation of a fuzzy multicriteria based Vertical Handoff Necessity Estimation (VHONE) scheme that determines the proper time for VHO, while considering the continuity and quality of the currently utilized service, and the end-users ’ satisfaction. 1
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