1,721,135 research outputs found
A survey of water utilities’ digital transformation: drivers, impacts, and enabling technologies
Full text linkAbstract Climate change and urbanization challenge utilities’ pursuit of water security worldwide. While water utilities are directly impacted by climate change, their operations also contribute to greenhouse gas emissions. Digital technologies have proven effective in improving utilities’ operations, leading to a more sustainable urban water cycle. However, the global progress of digital water transformation remains largely understudied. Here, we present the results of an online survey involving 64 utilities from 28 countries investigating the impacts of digital transformation on the water utility sector, its drivers, and key-enabling technologies. We found that the water distribution system is the entry point to further adoption of digital technologies in the whole urban water cycle. Furthermore, technology adoption is driven primarily by economic benefits, followed by government regulation and hydroclimatic factors. Starting from the survey results, we point out avenues for further research targeting a better understanding of the influence of regulation, corporate mindset, and consumer involvement for successful digital transformation
Leveraging power of learning capability upon manufacturing operations
No full textLearning capability (LC) is a special dynamic capability that a firm purposefully builds to develop a cognitive focus, so as to enable the configuration and improvement of other capabilities (both dynamic and operational) to create and respond to market changes. Empirical evidence regarding the essential role of LC in leveraging operational manufacturing capabilities is, however, limited in the literature. This study takes a routine-based approach to understand capability, and focuses on demonstrating leveraging power of LC upon two essential operational capabilities within the manufacturing context, i.e., operational new product development capability (ONPDC), and operational supplier integration capability (OSIC). A mixed-methods research framework was used, which combines sources of evidence derived from a survey study and a multiple case study. This study identified high-level routines of LC that can be designed and controlled by managers and practitioners, to reconfigure underlying routines of ONPDC and OSIC to achieve superior performance in a turbulent environment. Hence, the study advances the notion of knowledge-based dynamic capabilities, such as LC, as routine bundles. It also provides an impetus for managing manufacturing operations from a capability-based perspective in the fast changing knowledge era.\ud
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
A Hybrid Modelling Framework for Ecosystem-Based Climate Change Adaptation Using System Dynamics and Bayesian Networks
No full textThe world is undoubtedly being threatened by the negative impacts of climate change. The degradation of the ecosystem, the loss of species and the endangerment of human health, livelihood and wellbeing are the main consequences of this ever-growing pressure. Coastal communities, particularly Small Island Developing States (SIDS), require extra attention due to their increased vulnerability and dependency on ecosystem services. Services provide by coral reefs are among the most fragile ecosystems that provide essential services to local SIDS communities.
Adaptation is a commonly accepted method by both international and local governments and authorities to tackle this phenomenon; adaptation refers to moderating the adverse effects of climate change through a wide range of actions to protect, accommodate or retreat. However, some adaptation actions and policies are not being adopted in a comprehensive approach, causing negative impacts on each other or possibly resulting in the failure of the desired and designed effectiveness. Thus, it is essential to use a holistic approach to identify adaptation solutions that are economically and practically feasible and realistic without compounding additional pressures on natural systems. The ecosystem-based approach is the key to dealing with common adaptation challenges and to addressing the needs of SIDS local communities.
However, planning for SIDS communities under rapidly changing, uncertain non-climatic and climatic conditions requires following a practical approach capable of fulfilling the general adaptation planning requirements as well as specific characteristics of SIDS traditional communities. Thus, the needs and features of successful adaptation planning were studied through a systematic literature review to create a practical and effective planning approach. A total of 650 relevant papers were initially nominated and reviewed; however, this number was reduced to 116 papers for thorough revision and detailed analysis. First, it was found that an integrative stepwise planning approach is required to integrate the results of multidisciplinary analyses and assessments and stakeholders' knowledge and opinions. Next, three crucial dimensions of a fully integrated climate change adaptation planning process—integration in assessment, modelling and adaptive responses—were identified. Adopting this novel approach, the multi-layered integrative climate change adaptation planning approach, is more likely to yield better climate change adaptation planning outcomes over the long-term.
In accordance with the proposed multi-layered integrative climate change adaptation planning approach, a hybrid dynamic modelling framework was developed to assess the health and resilience of coral reefs under different climate change scenarios and their consequential impacts on human wellbeing in Port Resolution, Tanna Island, Vanuatu. This framework follows a structured process and employs suitable techniques capable of dealing with different challenges, including the complexity and dynamicity of socioeconomic and environmental systems and impacts of trans-discipline variables. This multi-layered integrative approach employed structural analysis, fuzzy cognitive mapping (FCM), Bayesian networks (BN) and system dynamics (SD) techniques. Each of these techniques features its own benefits and limitations, and integrating these modelling tools can maximise their respective advantages by compensating for another's limitations.
First, the principal influential factors in coral reef health and ecosystem services were identified, and their causal relationships were subsequently mapped using the participatory FCM technique. As a result of structural and FCM analyses, the following outcomes were achieved: (i) system variables were identified and grouped under different categories including marine ecology, climatic, community and socioeconomic variables; (ii) all variables were assessed based on their level of influence on other variables; (iii) the interrelationships of all variables were mapped based on expert knowledge; and (iv) a preliminary scenario-based analysis was performed, and the role and significance of the factors in the time horizon of the study were determined. Next, the long-term perspective of the future health and resilience condition of coral reefs under different sets of management interventions was explored using the BN technique. The BN model was conceptualised using the results of the previously completed step (i.e., FCM). The BN technique was used to incorporate existing data and experts' knowledge and to predict the future conditions of coral reefs under different scenario settings. Finally, the SD modelling step investigated the nexus between environmental and economic values under different combinations of management or adaptation strategies over a long-term period, which is 50 years or by 2070. As an innovative approach, the SD model was parameterised from the outcome of the BN modellings, in which the existing data and information were insufficient to quantify the model. Furthermore, comparing the results of modelling outcomes and their respective sensitivity analyses supported the model behaviour testing process of the final SD model.
While each research stage has its own specific practical, methodological and scientific contribution, the main findings of this PhD research are: (1) sustainable management or adaptation planning of coastal coral reefs should be studied from a multidisciplinary socio-ecological lens; (2) identifying, assessing and prioritising all potential adaptive responses, including engineering, social and regulatory, through an integrated vulnerability assessment and decision-making process with all of their subsets is the key to success; (3) immediate actions to preserve coral reef health and resilience are required to protect the current flow of ecosystem services; (4) local management interventions are not likely to protect coral reefs under the worst-case climate change scenario; and (5) the steady and integrated implementation of management strategies alongside global mitigation efforts to minimise the impacts of climate change could protect the long-term flow of economic benefits and maintain functional coral cover despite economic loss over a short-term period. The predominant output of this study is a novel hybrid BN-SD modelling framework to support ecosystem-based climate change adaptation planning.Thesis (PhD Doctorate)Doctor of Philosophy (PhD)School of Eng & Built EnvScience, Environment, Engineering and TechnologyFull Tex
Evidence and Techniques to Derive Benefits from Multifunctional Energy Storage Systems at Low Voltage Distribution Level Including Renewable Generation
No full textReducing the combustion of fossil fuels for electricity generation and replacing them with renewable energy results in two major benefits for people. Public health is promoted with the breathing air being cleaner with reduced particulate concentration. Higher energy production from renewable energy sources (RESs) results in larger portion of the produced electricity being decarbonised thereby decelerating the climate change. Complementary to the benefits that are brought by the RESs to the public health and to the battle with the climate change, are the technological advances of components that are used in RESs installations. For photovoltaic (PV) panels and dc/ac converters, the purchase costs have decreased, and the efficiency and reliability have increased. Considering the significant benefits that RESs bring to people’s lives global scale efforts are in progress to increase the share of renewable energy in the energy mix.
The central aim of this research work was to allow higher PV penetration levels to be achieved while using energy storage systems (ESSs) for grid support purposes. ESSs powered by RESs add the missing flexibility to the renewable energy thereby the grid integration of RESs can be increased. The renewable energy that was charged by the ESSs to facilitate the integration of RESs, is dispatched to another period of the day where the grid needs support, thereby complementary applications are performed by the ESSs.
For the research a real-life low voltage (LV) distribution network was modelled and it was used in the simulations. The real-life LV network maintains a complex loop arrangement and it is predominantly resistive. The practical LV network is situated at the city of Brisbane in Queensland, Australia. Load profiles measured at the LV network, were proliferated by using Normal distributions, and they were used in the simulations. Environmental data (i.e., solar irradiation and ambient temperature) that were measured at the city of Brisbane, PV panel datasheet values, the one-diode model, as well as the efficiency of the inverter that is representative of a wide range of operation were employed for the calculation of the power generation profiles of the rooftop PV installations that existed at the LV network. Depending on the operational phase of the ESS (i.e., charging, discharging or idling) another equation was used to estimate the energy stored in each storage unit each operating state. The association of power sign and power direction that is used for generators was also followed by the ESSs for power-flow purposes. The comprehensive Newton-Raphson method determined the power-flow and the loading of grid components. The total of the operational grid constraints were included in the simulations namely transmission lines loading, terminal voltage variation, and substation transformer loading. The droop control introduced in this work generated dispatch commands for the ESSs, and maintained a sound grid operation during periods of excessive PV generation. Voltage stability analysis was performed, and to the voltage stability curves was applied for the first time in the literature the Pythagorean theorem, that jointly captures the effect of ESSs on both voltage stability and voltage quality.
Key research findings:
- Low PV penetration (i.e., 9.12%) is beneficial for the grid because it decreases the loading levels of grid components and it improves voltage profiles.
- Grid operation with no support is unable to accommodate high PV penetration levels such as 70%, because the reverse power-flow challenges both the thermal limits of grid components and the statutory voltage limits.
- The lowest cost solution was identified for placement and sizing of the community level (CL) ESS.
- When the operation of the electrical network is supported by the CL ESS, that absorbs excessive power surpluses according to the dispatch commands it receives from the herein developed droop control, 70% PV penetration becomes feasible, while a sound grid operation is maintained at all times.
- For 70% PV penetration, the CL ESS was first dispatched by using fixed droop (FD) control, and then, the dispatch commands of the CL ESS were generated by employing variable droop (VD) control. For 70% PV penetration, both FD control and VD control were able to generate dispatch commands that maintain the total of the grid parameters within the allowable range.
- Two ESSs deployment options have been explored in this work. It was found that the CL ESS has higher sizing requirements and cost as compared with the sizing requirements and cost of three ESSs distributed (DIST) at selected terminals of the LV network. The three ESSs administer less power to achieve the control aim, iii therefore their sizing requirement and in turn their cost is lower as compared with the higher sizing requirement and higher cost of the CL ESS.
- The cost oriented sensitivity analysis that was performed indicated that the longer the distance of the three ESSs from the critical grid parameters the higher their sizing requirements and therefore their cost. The lowest cost solution was found when the three ESSs were placed directly at the critical terminals of the LV network. When the ESSs were placed directly at the critical terminals of the LV network, they had to manage the minimum amount of power and energy to achieve the control aim. This reduced the sizing requirements of the ESSs and led to the lowest cost solution for ESSs placement.
- Steady-state voltage stability analysis was performed. When only one of the three ESSs supported the grid operation at night the voltage stability improved. The voltage stability kept improving as the second and the third ESSs also supported the grid operation. When the CL ESS injected power into the grid at night, the voltage stability benefit was greater as compared with the voltage stability benefit that was recorded when all three distributed ESSs supported the grid operation. The higher amount of energy that was discharged into the grid by the community level ESS, was available at the expense of greater sizing requirement and higher cost compared with the distributed ESSs case.
- Initially, the effect of ESSs on voltage stability and on voltage quality was identified independently. In turn, voltage stability curves and the Pythagorean theorem were combined to produce the novel voltage stability and quality index (VSQI ). The comparison of the novel VSQI value in the absence of ESSs and as more ESSs were included in the dispatch, was indicative of the beneficial role of ESSs on both voltage stability and voltage quality.
- The impeccable grid support capabilities of ESSs have been demonstrated in this work, by the aggregated applications that have been performed here by the same ESSs.
The present PhD research work has made the following contributions:
- A novel droop control was introduced in this work that generated dispatch commands for the ESSs and maintained the total of the grid parameters within iv their statutory limits. The novel droop control generated dispatch commands in response to the expected power surplus at the substation transformer.
- The herein developed droop control outperforms other droop control methods that exist in the literature that only cater for one of the grid parameters. Further, the droop control introduced in this work is applicable to any grid arrangement because the slope of the droop characteristic is identified iteratively.
- With the application of technically sound methods the impeccable grid support capabilities of ESSs have been demonstrated. Specifically, the storage units shifted renewable energy from morning to night, shaved the peak load, enhanced voltage stability, improved voltage quality, and reduced the loading levels of transmission lines and of the substation transformer. Solely the present research work has applied sound technical methods to demonstrate that the abovementioned applications have been performed by the same ESSs.
- The present research work has introduced the novel VSQI that jointly captures the beneficial effect of ESSs on voltage stability and on voltage quality. For each scenario, the voltage stability curve was obtained, therefrom the coordinates that correspond to voltage stability and voltage quality were identified, while the Pythagorean theorem was used to calculate the VSQI of the scenario. The increase of the VSQI value as more ESSs were included in the dispatch, represents the benefit of ESSs on both voltage stability and voltage quality.
- Comparison of FD control and VD control was performed in terms of compensation accuracy and CL ESS cost. The repetitive overcompensation of FD control increased the rated energy of the CL ESS that in turn elevated the cost of the storage unit. The dispatch commands of higher accuracy generated by VD control, additively diminished the amount of energy the CL ESS had to handle, therefore the rated energy of the storage unit was reduced. Eventually, the reduced rated energy when the CL ESS was dispatched by VD control improved the cost of the storage unit.
- The present research work has demonstrated that the same ESSs are able to provide multiple support to the grid. During the planning stage, the present combined grid support should be compared with the grid support reported in other works, for the grid planner to select the appropriate grid support device.Thesis (PhD Doctorate)Doctor of Philosophy (PhD)School of Eng & Built EnvScience, Environment, Engineering and TechnologyFull Tex
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