Zonal Network Research Articles

Comparison of Radial and Zonal DC Distribution System for Hybrid-Powered Trimaran Vessels Power Flow Analysis

Two types of power grid structures have been applied to the shipboard, namely the radial and the zonal networks. These two distribution systems have different power characteristics transmitted to the bus panel. The power characteristics affect the power density of each bus at each level. This paper explores the power characteristics of the radial type and the zonal type power grid structures in a DC distribution system. The power flow of both distribution system types has been determined by the Adaptive Newton-Raphson method and simulated based on ship operation conditions using Electrical Power System Analysis Software (ETAP). In determining the power flow for the DC distribution system, one-line diagram modelling is developed in radial type and zonal type. The simulation parameters are adjusted to the operating conditions of the ship, namely sailing, manoeuvring, loading-unloading, and at the port. After that, a power flow simulation has been carried out using ETAP and has showed what had successfully implemented the power flow in the DC distribution system for radial and zonal types. The capacity of Power generation is adequate all through a ship operation. The characteristics of the transmitted power show that the zonal type has a higher efficiency rate than the radial type. The zonal type has a backup bus so that the electrical system's reliability is higher than the radial type. However, the power distributed to the equipment bus from the load bus, both the radial type and the zone type, has the exact power requirements.

FPGAs for the Zonal Service-oriented Network Architecture in Cars

FPGAs for the Zonal Service-oriented Network Architecture in Cars

Двухскоростной асинхронный двигатель как источник опасности электропоражения в условиях эксплуатации технологических участков угольных шахт

Hazardous states of the mine zonal electrical network are caused by the reversed energy flows of induction motors of the energy-consuming equipment in the run-down mode after the power supply is switched off. The electromotive force (EMF) induced in the powered-off stator windings of the dual-speed motors due to the transformer effect also pose a danger of electric shock. The paper presents a methodology and the results of studying the formation of induced EMFs in the powered-off stator windings of dual-speed induction motors, including the run-down mode and the functions that impact on the electromagnetic parameters. Analysis of the impact degree of these induced EMFs on the electrical safety parameters as part of the mine zonal electrical network is presented.

A climate network perspective on the intertropical convergence zone

Abstract. The intertropical convergence zone (ITCZ) is an important component of the tropical rain belt. Climate models continue to struggle to adequately represent the ITCZ and differ substantially in its simulated response to climate change. Here we employ complex network approaches, which extract spatiotemporal variability patterns from climate data, to better understand differences in the dynamics of the ITCZ in state-of-the-art global circulation models (GCMs). For this purpose, we study simulations with 14 GCMs in an idealized slab-ocean aquaplanet setup from TRACMIP – the Tropical Rain belts with an Annual cycle and a Continent Model Intercomparison Project. We construct network representations based on the spatial correlation patterns of monthly surface temperature anomalies and study the zonal-mean patterns of different topological and spatial network characteristics. Specifically, we cluster the GCMs by means of the distributions of their zonal network measures utilizing hierarchical clustering. We find that in the control simulation, the distributions of the zonal network measures are able to pick up model differences in the tropical sea surface temperature (SST) contrast, the ITCZ position, and the strength of the Southern Hemisphere Hadley cell. Although we do not find evidence for consistent modifications in the network structure tracing the response of the ITCZ to global warming in the considered model ensemble, our analysis demonstrates that coherent variations of the global SST field are linked to ITCZ dynamics. This suggests that climate networks can provide a new perspective on ITCZ dynamics and model differences therein.

An Analysis of Re-configured Blood Transfusion Network of Urban India to Improve the Service Level: a Simulation Approach.

In India, blood banks are owned by state hospitals, private hospitals, NGOs and private laboratories. The aim of this study is to improve the service levels of the blood supply chain by maximizing the availability and minimizing the wastage of blood. New configuration approaches are adapted from the successful methods of manufacturing sectors. In this retrospective cross-sectional study, whole blood (WB) demand and supply data between April 2015 to March 2016 has been taken. Data analytics tool "R" is used for statistical analysis. Two new configurations, namely a) Zonal Network and b) Pull system models have been developed to compare the existing blood supply chain. The performances of the proposed configurations have been compared with the existing system using suitable indicators computed using Arena simulation software12.0. The total shortage index (TSI) and total wastage index (TWI) are used as indicators of performance measures. Weights are assigned for shortage and wastage indices to the reconfigured models. The pull system model outperforms existing model and zone model by achieving zero wastage. In transfusion medicine, importance is given to the achievement of lesser percentage shortage than wastage. If the WB inventory in blood centers is sufficient enough and we have more than one zone for distribution, then we can reduce wastages level in the blood supply chain.

Scalable Perimeter Control Strategy of Road Network Based on the Macroscopic Fundamental Diagram

To alleviate regional traffic congestion in large areas of the urban zonal road network, an extensible perimeter control strategy based on the macroscopic fundamental diagram is proposed to improve the effectiveness of the entire urban network. The proposed strategy considers the fleet storage capacity of the links, avoids over queuing, and establishes a constraint of perimeter control and a regional feedback control model. A new extended boundary is formed by dynamically adjusting the control boundary of the protected area in real time, and a feedback gate is set at the junction of extended boundary to restrict the traffic flow in the road network of the congested area. To verify the effectiveness of the proposed strategy, a Sioux Falls test network is used as the research area, and the effect of the proposed strategy is evaluated in Vissim. Simulation results show that the implementation of the scalable perimeter control strategy improves the operation index of the road network, and a wide range of congestion is obviously alleviated.

Epigenomic map of human liver reveals principles of zonated morphogenic and metabolic control

A deeper epigenomic understanding of spatial organization of cells in human tissues is an important challenge. Here we report the first combined positional analysis of transcriptomes and methylomes across three micro-dissected zones (pericentral, intermediate and periportal) of human liver. We identify pronounced anti-correlated transcriptional and methylation gradients including a core of 271 genes controlling zonated metabolic and morphogen networks and observe a prominent porto-central gradient of DNA methylation at binding sites of 46 transcription factors. The gradient includes an epigenetic and transcriptional Wnt signature supporting the concept of a pericentral hepatocyte regeneration pathway under steady-state conditions. While donors with non-alcoholic fatty liver disease show consistent gene expression differences corresponding to the severity of the disease across all zones, the relative zonated gene expression and DNA methylation patterns remain unchanged. Overall our data provide a wealth of new positional insights into zonal networks controlled by epigenetic and transcriptional gradients in human liver.

Zonal network solution of temperature profiles in a ventilated wall module

A ventilated wall module is an outdoor air-intake device that can clean the drawn air, reduce heat loss or gain, and insulate outdoor noises. It contains a solar board, air cavities, and an air filter. This investigation proposes a zonal network model to efficiently predict temperature profiles in a ventilated wall module. The thermal network is established by applying an energy balance to each network node. The outdoor temperature, indoor temperature, and solar irradiation intensity are specified as boundary parameters. The proposed model is validated by the measured temperatures in a prototype model. The results show that the proposed model provides reasonably accurate temperatures with a maximum gap of 3°C between the prediction and the measurement. The temperature profiles approach straight lines when the mass flow rate significantly increases. A similar trend is observed when the solar irradiation intensity, the solar board absorptivity, or the glass transmitivity dramatically decreases.

Zonal Reserve Model for Renewable Power Integrated System

Abstract Considering transmission capabilities and renewable integration, zonal regulation and spinning reserve requirements are discussed to handle uncertainty of load and renewable energy as well as any N-1 outage. A new zonal reserve model is proposed in the paper including reserve dispatched time constraints, zonal reserve requirements and network security constraints using the method of chance constrained programming. Analysis on the IEEE 39 system demonstrates the model can schedule zonal energy, regulation and spinning reserve in an economic way for a renewable power integrated system.

An improved method to calculate injection shift keys

Transmission network constraints become increasingly relevant in generation scheduling models, given the ongoing integration of market zones and the deployment of renewables in remote areas. However, a full nodal network representation in generation models is often not possible due to computational limitations. Therefore, reduced zonal network models are needed. A crucial step in the nodal-zonal network reduction is the calculation of injection shift keys (ISKs). Injection shift keys denote the nodal contribution to the zonal generation balance and are needed to compile different nodes into one equivalent node. This paper discusses injection shift keys in detail and proposes an improved method to calculate them. According to the improved method, the generation and load portfolio is split up in different categories, and injection shift keys are determined separately for each category. A case study of the central European electricity system indicates that the improved method is able to approximate the nodal network without a considerable increase in computational cost.

Renewable Energy Integration in Zonal Markets

In this paper, we investigate the impact of zonal network management in the operation of power systems with significant levels of renewable energy integration. Our study is inspired by the current state of the European energy market, and we focus on a case study of the Central Western European (CWE) system. First, we present a hierarchy of models that account for unit commitment, the separation of energy and reserves, and the simplified representation of transmission constraints in a zonal market, in order to examine the impact of these factors on efficiency in a regime of large-scale renewable energy integration. Second, we simulate operations of the CWE system under the zonal market design using a detailed instance that consists of 656 thermal generators, 679 nodes, and 1073 lines, with multiarea renewable energy production and 15-minute time resolution. Zonal market operations are compared against deterministic and stochastic unit commitment using high-performance computing in order to tackle the scale of the resulting models. We find that market design can have an influence on cost efficiency which far exceeds the benefits of stochastic unit commitment relative to deterministic unit commitment. We conduct a detailed analysis of the numerical results in order to explain the relative performance of the different models.

SSL: Signal Similarity-Based Localization for Ocean Sensor Networks.

Nowadays, wireless sensor networks are often deployed on the sea surface for ocean scientific monitoring. One of the important challenges is to localize the nodes’ positions. Existing localization schemes can be roughly divided into two types: range-based and range-free. The range-based localization approaches heavily depend on extra hardware capabilities, while range-free ones often suffer from poor accuracy and low scalability, far from the practical ocean monitoring applications. In response to the above limitations, this paper proposes a novel signal similarity-based localization (SSL) technology, which localizes the nodes’ positions by fully utilizing the similarity of received signal strength and the open-air characteristics of the sea surface. In the localization process, we first estimate the relative distance between neighboring nodes through comparing the similarity of received signal strength and then calculate the relative distance for non-neighboring nodes with the shortest path algorithm. After that, the nodes’ relative relation map of the whole network can be obtained. Given at least three anchors, the physical locations of nodes can be finally determined based on the multi-dimensional scaling (MDS) technology. The design is evaluated by two types of ocean experiments: a zonal network and a non-regular network using 28 nodes. Results show that the proposed design improves the localization accuracy compared to typical connectivity-based approaches and also confirm its effectiveness for large-scale ocean sensor networks.

Investigation of road network features and safety performance

The analysis of road network designs can provide useful information to transportation planners as they seek to improve the safety of road networks. The objectives of this study were to compare and define the effective road network indices and to analyze the relationship between road network structure and traffic safety at the level of the Traffic Analysis Zone (TAZ). One problem in comparing different road networks is establishing criteria that can be used to scale networks in terms of their structures. Based on data from Orange and Hillsborough Counties in Florida, road network structural properties within TAZs were scaled using 3 indices: Closeness Centrality, Betweenness Centrality, and Meshedness Coefficient. The Meshedness Coefficient performed best in capturing the structural features of the road network. Bayesian Conditional Autoregressive (CAR) models were developed to assess the safety of various network configurations as measured by total crashes, crashes on state roads, and crashes on local roads. The models’ results showed that crash frequencies on local roads were closely related to factors within the TAZs (e.g., zonal network structure, TAZ population), while crash frequencies on state roads were closely related to the road and traffic features of state roads. For the safety effects of different networks, the Grid type was associated with the highest frequency of crashes, followed by the Mixed type, the Loops & Lollipops type, and the Sparse type. This study shows that it is possible to develop a quantitative scale for structural properties of a road network, and to use that scale to calculate the relationships between network structural properties and safety.

Macrolevel Model Development for Safety Assessment of Road Network Structures

Traffic safety is beginning to receive increasing attention at the stage of transportation planning. Although the features of road networks are an essential aspect of transportation planning, studies of the safety effects of network patterns remain limited. In this study, macrolevel safety models were developed to explore the relationship between crash occurrence and several underlying variables, including demographic, land use, and road network variables. Different indices (e.g., the meshedness coefficient and closeness centrality) of network structures were developed to examine the effects of the network structure on safety at the zonal level. In many cases, a large percentage of the crash locations (especially for arterial crashes) was not related to the traffic analysis zones (TAZs) where drivers lived. To link crashes and features properly at the zonal level, crashes of each TAZ were modeled separately for non-state-maintained arterials (i.e., off-system roadways) and state-maintained arterials (i.e., on-system roadways). Several conditional autoregressive Bayesian models that incorporated the spatial correlation of nearby zones were developed. Estimation results showed that crashes occurring on non-state-maintained roads correlated more closely with the zonal network structure and the demographic characteristics inside the TAZ than did crashes occurring on state-maintained arterials; crashes on state-maintained arterials correlated more closely with the traffic and features of the major roads. The categorical variable generated from the meshedness coefficient captured well the nature of the relationship of network patterns to off-system road crashes. The results of this study indicate that both the roadway type and the structure of the road network should be considered when TAZ-level safety models are developed.

A Novel Topology for the Zonal Network with Wireless Coverage

In this paper, we propose a banyan-tree topology for the wireless coverage along the road or railway, which is characterized as a zonal network. Theoretical analysis and numerical studies show that the proposed ban-yan-tree topology is appropriate for the zonal network with the Wireless Mesh Network (WMN) technology, which is feasible to deploy and has the enhanced robust, improved bandwidth with this topology.

Development of an integrated model for airflow in building spaces

In building energy simulation, an integrated modelling of airflow in the building needed. Therefore, in this paper two approaches are used for building energy simulation: zonal network for modelling of the building segments and Computational Fluid Dynamics (CFD) for modelling of the airflow. It is noted that a synchronize solution process is needed for the building and the CFD equation-sets. For this purpose an iterative procedure is used to corresponding solution of these equations.

A tabu search algorithm for self-healing ring network design

We consider the problem of designing self-healing rings in order to protect the transmission of telecommunication demands in a zonal network. This problem stems from a real application with operational constraints such as dual homing and hop limit per ring. A modeling approach taking into account ring interactions is proposed as well as a tabu search heuristic for solving it. Computational results for a comprehensive set of real and randomly generated instances are presented.

Locational Market Power Screening and Congestion Management: Experience and Suggestions

The existing New England electricity market follows a uniform pricing system: infra-marginal generators are paid a uniform clearing price while constrained-on generators are paid bid prices subject to a locational market power screen. In this paper, we first report the operation experience of this approach during the market's first two years. We then briefly review the NEPOOL locational pricing proposal being implemented. Two new approaches for locational market power screening are presented. The first one is based on a zonal network model and the second is based on a nodal transmission model. Both approaches are being evaluated by an independent consultant and are be to recommended to NEPOOL. Test results of both approaches are included.

The uniform system of seismic observations of the U.S.S.R. and prospects of its development

In the period up to about 1965 the stations of the Soviet seismic network distributed throughout the regions of the U.S.S.R. had increased in number to in excess of one hundred. In order that the data provided by such stations could be applied to the study of the earth's structure rather than merely regional problems, and to the determination of the seismic character of the territory of the U.S.S.R. as a whole, it became necessary to institute the Unified System of Seismic Observations (USSO) of the U.S.S.R. The standardization of data and organization of the stations into a system of base and regional stations and also into zonal networks, covering specific seismic zones of the U.S.S.R., has been effected within the USSO. Currently the USSO consists of 215 stations mostly equipped with high-sensitivity instruments with magnifications of 20–50,000 and dynamic ranges of 35–40 dB. To exploit the large volume of observational data obtained through the system it is necessary to devise a programme for the transmission, processing and storage of data on the necessary scale. In the present paper we describe the methods which have been adopted and those which are in the course of development for such a programme in the U.S.S.R.