3D visibility of 4D convex polyhedra

In mathematics we can easily generalize Euclidean 3D space to n-dimensional one for arbitrary n>3. The task, how one can express n-dimensional objects in 3D or even in 2D, arises. In the paper the generalization of the back-volume culling algorithm is analyzed

Determination of the initial stress tensor from deformation of underground opening -- theoretical background and applications

summary:In this paper a method for the detection of initial stress tensor is proposed. The method is based on measuring distances between some pairs of points located on the wall of underground opening in the excavation process. This methods is based on the solution of eighteen auxiliary problems in the theory of elasticity with force boundary conditions. The optimal location of the pairs of points on the wall of underground work is studied. The pairs must be located so that the condition number of a certain matrix has the minimal value, which guarantees a reliable estimation of initial stress tensor

RTIN-based strategies for local mesh refinement

summary:Longest-edge bisection algorithms are often used for local mesh refinements within the finite element method in 2D. In this paper, we discuss and describe their conforming variant. A particular attention is devoted to the so-called Right-Triangulated Irregular Network (RTIN) based on isosceles right triangles and its tranformation to more general domains. We suggest to combine RTIN with a balanced quadrant tree (QuadTree) decomposition. This combination does not produce hanging nodes within the mesh refinements and could be extended to tetrahedral meshes in 3D

Impact of the Ground on the Series Impedance of Overhead Power Lines

An overhead power line is a structure used in the electric power system to transmit electrical energy. The performance of overhead power lines depends on their parameters. There are four basic electrical parameters of power lines: resistance, inductance, capacitance, and shut conductance. The paper focuses on the calculation of the series impedance of overhead lines (resistance and inductance) by three different methods (Carsonʹs method, Rüdenbergʹs method and the theory of complex penetration depth) considering the impact of the ground return path. There is also the comparison of these methods and their application on models of real power lines of different voltage levels provided in this paper

Optimal processing node discovery algorithm for distributed computing in IoT

© 2015 IEEE.The number of Internet-connected sensing and control devices is growing. Some anticipate them to number in excess of 212 billion by 2020. Inherently, these devices generate continuous data streams, many of which need to be stored and processed. Traditional approaches, whereby all data are shipped to the cloud, may not continue to be effective as cloud infrastructure may not be able to handle myriads of data streams and their associated storage and processing needs. Using cloud infrastructure alone for data processing significantly increases latency, and contributes to unnecessary energy inefficiencies, including potentially unnecessary data transmission in constrained wireless networks, and on cloud computing facilities increasingly known to be significant consumers of energy. In this paper we present a distributed platform for wireless sensor networks which allows computation to be shifted from the cloud into the network. This reduces the traffic in the sensor network, intermediate networks, and cloud infrastructure. The platform is fully distributed, allowing every node in a homogeneous network to accept continuous queries from a user, find all nodes satisfying the users query, find an optimal node (Fermat-Weber point) in the network upon which to process the query, and provide the result to the user. Our results show that the number of required messages can be decreased up to 49% and processing latency by 42% in comparison with state-of-the-art approaches, including Innet

Use of Specialized Devices to Power Flow Control in Power Systems

This article discusses specialized devices forthe power flow control in power systems. Today it is anactual topic because of permanent increasing power flow inthe transmission lines. This trend can lead to overloading oftransmission lines and can endanger the security of electricenergy supply

Influence of State of Charge Level on Frequency Control Reserve Provision by Energy Storage Systems

Batteries in transmission grids can provideancillary network services, such as primary frequencyresponse, voltage control in network nodes or back uppower. The Battery Energy Storage Systems (BESS) is oftenthe most limiting factor within their more extensive usagefor the frequency control. Because of this it is necessary toadjust the system charging SoC and the performance ofbattery systems so that they fulfil the same requirements asthose ones which are applied in case of conventionalproviders of primary frequency control. This article saysmore about the possibilities of using and stability of batterysystems and their ability to be a part of the ancillaryservices providers

Energy-Efficient Communication in Wireless Networks

This chapter describes the evolution of, and state of the art in, energy‐efficient techniques for wirelessly communicating networks of embedded computers, such as those found in wireless sensor network (WSN), Internet of Things (IoT) and cyberphysical systems (CPS) applications. Specifically, emphasis is placed on energy efficiency as critical to ensuring the feasibility of long lifetime, low‐maintenance and increasingly autonomous monitoring and control scenarios. A comprehensive summary of link layer and routing protocols for a variety of traffic patterns is discussed, in addition to their combination and evaluation as full protocol stacks

Economic aspects of biomass utilization

This paper deals the overview of characteristics and prices of Biomass. The agriculture in Hungary has big potential in energy production from biomass. Economic aspects of the utilizing the Biomass for energy production is very important. The price of biomass production mainly depends on internal agricultural preferences, on biomass transformation prices and the government biomass utilization support