41 research outputs found

    Spatial Solutions and Solution Spaces: The use of Virtual and Augmented Reality in Design Exploration

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    The recent wave of Virtual and Augmented Reality (VAR) technologies has coincided with new technologies for processing, analyzing and evaluating large amounts of data. In general, the purpose of Data Visualization is to enable the user to discover and understand patterns in data. Good visualizations present large amounts of data in a way that is easily understood, and good interactive visualizations promote intuitive means of exploring relationships. Over the past few years many researchers have looked into the development of immersive Virtual Environment platforms for Big Data visualization, such as, iViz (Donalek et al, 2014) and the work carried out by Masters of Pie and Lumacode for the Big Data VR Challenge in 2016 (Lumapie, 2016). Filtering, combination and scaling have all been identified elsewhere as important interactive techniques used in contemporary data visualization (Olshannikova et al, 2015). Of these, scaling may be the most familiar to architects: for centuries, designers have attempted to experience architectural space in different scales simultaneously, by using models at different scales (Yaneva, 2005), and by employing various drawing techniques to achieve an embodied perception of the designed space. With the use of VAR technologies this becomes easier than ever. At the same time, designers increasingly must understand not just the experience of a design proposal but also the data associated with it

    Influence of kNN-Based Load Forecasting Errors on Optimal Energy Production

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    This paper presents a study of the influence of the accuracy of hourly load forecasting on the energy planning and operation of electric generation utilities. First, a k Nearest Neighbours (kNN) classification technique is proposed for hourly load forecasting. Then, obtained prediction errors are compared with those obtained results by using a M5’. Second, the obtained kNN-based load forecast is used to compute the optimal on/off status and generation scheduling of the units. Finally, the influence of forecasting errors on both the status and generation level of the units over the scheduling period is studied

    Performance-Based Pricing of Frequency Regulation in Electricity Markets

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    The emergence of high penetration of renewable energy sources in the energy mix of power systems has substantially increased the need for faster-ramping resources participating in the frequency regulation service procured via market mechanisms by the system operators. However, current market mechanisms do not properly align the incentives for participation since resources are not compensated for the actual frequency regulation they provide nor for the accuracy with which they follow the automatic generation control (AGC) dispatch signal. In this paper, we evaluate the current mechanisms for procuring, dispatching and compensating resources for the frequency regulation service. We also propose a comprehensive approach for calculating the performance payment that includes the actual service they provide and the accuracy with which they follow the AGC signal. Finally, we perform a study by deploying actual operational AGC data for analyzing the proposed methodology

    Application of zonal pricing in Greece's electricity market

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    Greece's electricity market is divided in two zones, North and South, due to a generation-consumption system configuration that creates a significant transmission bottleneck from North to South. Clearly, a zonal pricing approach for energy provides the right incentive for the installation of new generation near consumption, if the zonal configuration reflects actual system and operational conditions. In this paper, we extend the zonal approach to include the time response-based ancillary services (also called "reserves"), which are commodities that are traded in the day-ahead market and are co-optimized with energy. We focus on the Day-Ahead Scheduling (DAS) market problem, which we formulate as a Security-Constrained Unit-Commitment problem whose objective is to co-optimize energy and reserves, taking into account the generation units' commitment costs. We model the DAS market problem as a Mixed-Integer Linear Programming problem that is solved every day, simultaneously for all 24 hours of the next day. Dual analysis of the problem and calculation of shadow prices provides useful insight on how prices for each commodity are set in the presence of binding resource, transmission or zonal reserve constraints. We use a simplified model of the Greek electricity system that includes only thermal plants to illustrate the developed methodology, the resulting market solutions and unit schedules, and the energy and ancillary services marginal prices. We also analyze and discuss issues such as the interaction between the commodities of energy and ancillary services under the marginal pricing approach

    Market design for the simultaneous optimization of the Day-Ahead market and the reliability unit commitment applications

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    The design of restructured electricity markets requires a mechanism to ensure that differences between the bid-in demand that clears in the Day-Ahead Market (DAM) and the ISO's demand forecast do not compromise reliability requirements. This mechanism is usually called Reliability (or Residual) Unit Commitment (RUC), and is deployed to procure additional resources, beyond the DAM energy schedules, to meet the demand forecast. In this paper, we present the theoretical foundation of the RUC process and key important considerations in implementing the RUC application. We also provide a description of the general sequential approach in which the DAM application is executed first and then the RUC process is completed. We then offer the design framework for the implementation of an integrated approach which combines the functionality of the DAM and the RUC into one market application. The integrated approach offers substantial efficiencies by procuring all DAM products simultaneously. © 2013 IEEE

    Day ahead energy market and Reliability Unit Commitment: An integrated approach

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    The restructured electricity markets typically involve a Day-Ahead Market (DAM), which clears bid-in demand that may be generally different (lower) than the demand forecast. This difference gives rise to reliability concerns to the Independent System Operators (ISOs), which are addressed with the deployment of a mechanism that is usually called Reliability (or Residual) Unit Commitment (RUC). Currently, the ISOs execute the RUC process after the DAM application, to procure additional resources, beyond the DAM energy schedules, to meet the demand forecast. In this paper, we compare the currently employed sequential approach, with a proposed integrated approach which combines the functionality of the DAM and the RUC into one market application. We present the market model including all market commodities, namely energy, ancillary services and RUC capacity, for both methodologies, and apply them on a realistic test case, using actual market/system data. We derive quantitative and qualitative results for a practical system, which illustrate the value of the integration of the market and the reliability functions in the forward spot market. The key conclusion from our simulation runs, is that the integrated approach offers substantial efficiencies by procuring all DAM products simultaneously. © 2014 Power Systems Computation Conference

    Impacts of virtual power plant auctions on the Greek electricity market

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    Over the last 15 years, Virtual Power Plant (VPP) products have created significant interest and have become a popular instrument of competition policy. In this paper we present a high-level design of VPP products and auctions and a brief review of the international experience. We consider the application of VPPs in the Greek electricity market, intended to facilitate the opening of the retail market. We simulate the day-ahead market for a yearly period and discuss the results. We are mainly interested in the change of the incumbent's bidding behaviour as a result of the retail market opening and its impact on the market outcome

    A Thorough Analysis of the Endocrown Restoration: A Literature Review

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    Aim: The aim of this literature review is to determine whether endocrowns are a reliable alternative for endodontically treated teeth with extensive loss of tooth structure, the indications and contraindications of this restorative choice, the principles that should be followed for tooth preparation and which material is most appropriate for endocrown fabrication. Background: Rehabilitation of endodontically treated teeth with severe coronal destruction has always been a challenge for the dental clinician. Until recently, the fabrication of a metal-ceramic or all-ceramic full-coverage crown along with a metal or glass fiber post has been the “gold standard” proving its efficacy via numerous clinical studies. With the development of CAD/CAM technology and the evolution of dental materials, new minimally invasive techniques have been introduced with less need for adjustments and less incorporation of structural defects. One of them, the “monoblock technique,” proposed by Pissis in 1995, was the forerunner of endocrown restoration, a term used by Bindl and Mörmann to describe an all-ceramic crown anchored to the internal portion of the pulp chamber and on the cavity margins, thus obtaining macromechanical retention provided by the axial opposing pulpal walls and microretention attained with the use of adhesive cementation. Review results: Endocrowns require a decay-oriented preparation taking advantage of both the adhesion and the retention from the pulpchamber walls, they are strongly indicated in endodontically treated molars in cases where minimal interocclusal space and curved or narrow root canals are present and they should be manufactured from materials that can be bonded to the tooth structure. Conclusion: Endocrowns are a reliable alternative to traditional restorative choices, given that the clinicians respect the requirements and indications describing this technique. Clinical significance: Traditional restorative techniques demanding tooth substance removal and minimizing the opportunity for reinterventions should be reconsidered. © Jaypee Brothers Medical Publishers. 2021 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted use, distribution, and non-commercial reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated

    Using pervasive computing and open space design to transform the schoolyard into an educational setting

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    Recovery mechanisms in a joint energy/reserve day-ahead electricity market with non-convexities

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    The goal of this paper is to evaluate the incentive compatibility of several cost- and bid-based recovery mechanisms that may be implemented in a wholesale electricity market to make the generation units whole in the presence of non-convexities, which are due to unit commitment costs and capacity constraints. To this end, we simulate the bidding behavior of the participants in a simplified model of the Greek joint energy/reserve day-ahead electricity market, where we assume that the players (units) participate as potential price-makers in a non-cooperative game with complete information that is repeated for many rounds. The results suggest that a mechanism based on bid recovery with a regulated cap is quite promising. © 2010 IEEE
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