Search results for " generation"

Modelling of a prosumer’s substation in a district heating network: validation and dynamic analysis

Thermal grids will play a key role in the development of local energy communities and the achievement of 100% renewable societies. However, challenges are related to the capability of dealing with the increasing number of producers which could supply heat to thermal grids. Indeed, as in the case of the electricity grid, heat could be available for some hours in a day from RES plants installed at user level and distributed in the network (also referred to as “prosumers”). To achieve more reliable results when performing energy analyses of these innovative applications, there is a need to rely on accurate models of each component. For instance, substations are of paramount importance in the i…

A framework for data integration of offshore wind farms

2013

Abstract Operation and maintenance play an important role in maximizing the yield and minimizing the downtime of wind turbines, especially offshore wind farms where access can be difficult due to harsh weather conditions for long periods. It contributes up to 25–30% to the cost of energy generation. Improved operation and maintenance (O&M) practices are likely to reduce the cost of wind energy and increase safety. In order to optimize the O&M, the importance of data exchange and knowledge sharing within the offshore wind industry must be realized. With more data available, it is possible to make better decisions, and thereby improve the recovery rates and reduce the operational costs. This …

The hallmark of anonymity. Questions of authorship in the Hippocratic Corpus, specifically regarding the so-called 'Author C'

2020

Since Émile Littrés’ time a particular attention has been devoted to a group of Hippocratic treatises (On Generation/On the Nature of the Child + Book IV of Diseases) showing a significant range of affinities and common elements in language, style, tenor and thought. Studies by Hermann Grensemann (in the 1980s) contributed to further philological analysis of the peculiar traits of the so-called Hippocratic ‘author C’, widening the textual basis to be involved in the investigation (including gynaecological treatises like On Diseases of Women 1-2 as well as parts of Infertile Women). Recently new light has also been shed by Elizabeth Craik (editing 2009 the treatise On Glands) on the historic…

GAIML: A New Language for Verbal and Graphical Interaction in Chatbots

2008

Natural and intuitive interaction between users and complex systems is a crucial research topic in human-computer interaction. A major direction is the definition and implementation of systems with natural language understanding capabilities. The interaction in natural language is often performed by means of systems called chatbots. A chatbot is a conversational agent with a proper knowledge base able to interact with users. Chatbots appearance can be very sophisticated with 3D avatars and speech processing modules. However the interaction between the system and the user is only performed through textual areas for inputs and replies. An interaction able to add to natural language also graph…

A computational study of LP-based heuristic algorithms for two-dimensional guillotine cutting stock problems

2002

In this paper we develop and compare several heuristic methods for solving the general two-dimensional cutting stock problem. We follow the Gilmore-Gomory column generation scheme in which at each iteration a new cutting pattern is obtained as the solution of a subproblem on one stock sheet. For solving this subproblem, in addition to classical dynamic programming, we have developed three heuristic procedures of increasing complexity, based on GRASP and Tabu Search techniques, producing solutions differing in quality and in time requirements. In order to obtain integer solutions from the fractional solutions of the Gilmore-Gomory process, we compare three rounding procedures, rounding up, t…

In-Depth Analysis of Pricing Problem Relaxations for the Capacitated Arc-Routing Problem

2015

Recently, Bode and Irnich [Bode C, Irnich S (2012) Cut-first branch-and-price-second for the capacitated arc-routing problem. Oper. Res. 60(5):1167–1182] presented a cut-first branch-and-price-second algorithm for solving the capacitated arc-routing problem (CARP). The fundamental difference to other approaches for exactly solving the CARP is that the entire algorithm works directly on the typically sparse underlying graph representing the street network. This enables the use of highly efficient dynamic programming-based pricing algorithms to solve the column-generation subproblem also known as the pricing problem. The contribution of this paper is the in-depth analysis of the CARP pricing…

Effective Handling of Dynamic Time Windows and Its Application to Solving the Dial-a-Ride Problem

2015

A dynamic time window relates to two operations that must be executed within a given time meaning that the difference between the points in time when the two operations are performed is bounded from above. The most prevalent context of dynamic time windows is when precedence is given for the two operations so that it is a priori specified that one operation must take place before the other. A prominent vehicle routing problem with dynamic time windows and precedence is the dial-a-ride problem (DARP), where user-specified transportation requests from origin to destination points must be serviced. The paper presents a new branch-and-cut-and-price solution approach for the DARP, the prototypi…

Gluon mass generation in the presence of dynamical quarks

2013

We study in detail the impact of dynamical quarks on the gluon mass generation mechanism, in the Landau gauge, for the case of a small number of quark families. As in earlier considerations, we assume that the main bulk of the unquenching corrections to the gluon propagator originates from the fully dressed quark-loop diagram. The nonperturbative evaluation of this diagram provides the key relation that expresses the unquenched gluon propagator as a deviation from its quenched counterpart. This relation is subsequently coupled to the integral equation that controls the momentum evolution of the effective gluon mass, which contains a single adjustable parameter; this constitutes a major impr…

Monte Carlo simulation of high‐order harmonics generation in bulk semiconductors and submicron structures

2004

To qualify the feasibility of standard semiconductor materials and Schottky‐barrier diodes (SBDs) for THz high‐order harmonic generation and extraction, the harmonic intensity, intrinsic noise and signal‐to‐noise ratio are calculated by the Monte Carlo method when a periodic high‐frequency large‐amplitude external signal is applied to a semiconductor device. Due to very high signal‐to‐noise ratio heavily doped GaAs SBDs are found to exhibit conditions for frequency mixing and harmonic extraction that are definitively superior to those of bulk materials. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Design and performances of a high temperature superconducting axial flux generator

2013

An important quality index of electric machine is the power density: it is known that axial flux machine tends to have a higher power density than the radial machines. As a result they are becoming more and more used in applications where the power density is a critical issues. However, the best way to enhance the power density is to increase the value of the airgap field and this could be achieved by using a superconducting excitation. Many projects have been developed in the world in order to develop both superconducting generator and superconducting motor, but in most of these programs the geometry of the machine has been based on radial machines [1]. All of these approaches show the fea…