1,720,993 research outputs found
Comparison of Reconfigurable BESS and Direct Grid Installation for EV Fast Chargers: a Danish Case Study
No full textBattery energy storage systems (BESSs) are known as a potential solution to integrate renewables and electric vehicle (EV) charging in the power system. This article compares the direct grid installation of ultra-fast chargers (UFCs) with a hybrid system inclusive of a reconfigurable BESS, a photovoltaic (PV) unit, two UFCs and a grid connection. The hybrid system is simulated with an optimization model, which reveals that the overall efficiency of the system plays a major role in determining the power grid exchange. Results show that the hybrid system can increase the local PV consumption while reducing the grid impact of EV charging. Based on yearly results, the hybrid system shows potential for further improving the utilization of the BESS and unlocking new revenue streams
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Development of an ethogram for predatory behaviour in dogs (Canis familiaris)
No full textreservedThe aim of this study is to develop and validate an ethogram regarding the predatory behaviour in dogs (Canis familiaris).
The information on the topic present in literature are scarce and not scientifically proved yet, therefore the present research will try to attentively describe and demonstrate the precise sequence of motor patterns that composes the predatory behaviour in dogs. Indeed, Coppinger only postulated the dog predatory sequence to be composed of search, pointing, stalking, chase, capture by grab-biting and grab-killing, dissection and consumption, as the main objective of predatory behaviour is feeding. However, in this study, the stages were regrouped into five presumptive phases that are: searching, pointing, stalking, chasing and biting. Consequently, behavioural data were collected through the observation of a series of twenty amateur videos, gathered from free video sharing platforms, and used to identify and describe the different phases and, therefore, develop the ethogram.
Since the research is still ongoing, this paper will focus only on the pointing and staking phases, as the data of the other stages are still being collected and analysed. Nevertheless, the resulting ethogram contains the pointing and stalking behaviours with their relative description, each divided into three levels of complexity (general description, specific posture and body description and a sensory orientation report). It was noticed that the two phases presented multiples similarities, both in posture and in function (collecting information on the prey location without being noticed), with the only difference being motion, to approach the prey, during the stalking. Therefore, we are prone to thinking that pointing and stalking should be grouped into a single phase, rather than two separate ones.
In conclusion, both the method, developed to study behaviour, and the ethogram will be important for future studies on the predatory behaviour in dogs, like breed differences, triggers or predatory aggression prevention, but also for behavioural researches on other species.The aim of this study is to develop and validate an ethogram regarding the predatory behaviour in dogs (Canis familiaris).
The information on the topic present in literature are scarce and not scientifically proved yet, therefore the present research will try to attentively describe and demonstrate the precise sequence of motor patterns that composes the predatory behaviour in dogs. Indeed, Coppinger only postulated the dog predatory sequence to be composed of search, pointing, stalking, chase, capture by grab-biting and grab-killing, dissection and consumption, as the main objective of predatory behaviour is feeding. However, in this study, the stages were regrouped into five presumptive phases that are: searching, pointing, stalking, chasing and biting. Consequently, behavioural data were collected through the observation of a series of twenty amateur videos, gathered from free video sharing platforms, and used to identify and describe the different phases and, therefore, develop the ethogram.
Since the research is still ongoing, this paper will focus only on the pointing and staking phases, as the data of the other stages are still being collected and analysed. Nevertheless, the resulting ethogram contains the pointing and stalking behaviours with their relative description, each divided into three levels of complexity (general description, specific posture and body description and a sensory orientation report). It was noticed that the two phases presented multiples similarities, both in posture and in function (collecting information on the prey location without being noticed), with the only difference being motion, to approach the prey, during the stalking. Therefore, we are prone to thinking that pointing and stalking should be grouped into a single phase, rather than two separate ones.
In conclusion, both the method, developed to study behaviour, and the ethogram will be important for future studies on the predatory behaviour in dogs, like breed differences, triggers or predatory aggression prevention, but also for behavioural researches on other species
Grid integration of electric vehicles: battery degradation and user needs
No full textElectrification is a key solution to an emissions-free transport sector, but it also poses a number of technical challenges to the power system. On the one side, a proper description of charging behaviour is a cornerstone for electric vehicle (EV) integration in the power system. This is increasingly relevant when considering controllable charging, which makes the assessment of charging behaviour even more challenging. On the other side, controlled EV charging can offer substantial benefits to the power system, but the role of user needs is often neglected. This thesis investigates the technical and economic benefits of EV integration in the power system, taking into account user needs and battery considerations. The initial focus of the thesis is on available data to derive EV charging profiles. Main sources of data are classified into three groups - surveys, car trials, and charger trials - and valuable information for the modelling of charging profiles is identified per each source. To understand how these sources can be used in EV studies, a minimum level of data for deriving EV charging profiles is defined: battery capacity, charging power, plug-in state of charge (SOC), plug-in/out time and charged energy. Since these data are often not directly available, guidelines and limitations to using available information and avoiding assumptions are provided. An additional complication arises when considering controlled charging profiles because their derivation depends on users’ willingness to participate in controlled charging, whose knowledge is still limited on a large scale. This leads to the second direction of this thesis, where techno-economic benefits of controllable charging are investigated by assessing how they can be used to generate value for end-users. First, unidirectional EV smart charging is compared with the introduction of a battery energy storage system (BESS) to facilitate and promote grid integration of residential photovoltaic production. The two solutions show similar results in terms of self-sufficiency and economic savings. However, with the current BESS prices, smart chargers are substantially more attractive economically. Second, the provision of primary frequency regulation with EVs and vehicle-to-grid (V2G) chargers is investigated. The profitability of the service is found to be largely dependent on costs associated with charger conversion losses. Indeed, the additional wear of the battery due to service provision seems to be limited compared to energy conversion losses, representing only a few percentage points of total costs. However, battery lifetime remains a major concern for EV users and reliable estimations of the capacity are of great importance. This thesis addresses how battery capacity can be estimated by reducing the usage of resources and time. EV battery capacity can be estimated by measuring the energy flowing into the battery pack during a full charge cycle. For safety reasons the battery pack is not directly accessible, thus existing practice relies on the usage of DC chargers and expensive measurement equipment. This thesis shows that accurate estimations can be carried out by relying on AC chargers and battery management system (BMS) measurements, significantly simplifying existing methods. Extensive experimental activities are carried out on six different EV batteries, where data from BMS and expensive experimental equipment are collected and compared. BMS data are shown to provide accurate measurements for battery capacity estimation, with errors limited to a few percentage points for the newest vehicles. However, lengthy battery capacity measurements are often inconvenient for power system application studies, where simple-to-realize models are necessary to simulate battery behaviour over long time periods. This thesis takes the first steps in developing and validating a Li-ion EV battery pack model without the need for disassembling the battery from the vehicle. The model describes battery behaviour with errors limited to a few percentage points for all considered electrothermal-aging dynamics and shows the importance of considering the interactions between them. Finally, working with EV batteries gives additional complications both during measurements and model implementation. This is discussed in the thesis, while insights from an implementation and field testing perspective are provided as a relevant starting point for future investigations
Flexibility procurement by EVs in a Danish active distribution network: Study cases from the island of Bornholm
Get PDFModello per generare diversi charging patterns dei veicoli elettrici basato su dati reali. Implementazione ed analisi di due reti di bassa tensione danesi con diverse caratteristiche di carico. Analisi delle due reti con l'integrazione passiva ed attiva dei veicoli elettrici con diversi livelli di carica e penetrazione nel sistema. Analisi economica basata sull'utilizzo dei veicoli come componenti attivi del sistema per evitare sovraccarichi e problemi di bassa tensione.ope
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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