2,095 research outputs found
Energy storage design and integration in power systems by system-value optimization
Energy storage can play a crucial role in decarbonising power systems by balancing
power and energy in time. Wider power system benefits that arise from these
balancing technologies include lower grid expansion, renewable curtailment, and
average electricity costs. However, with the proliferation of new energy storage
technologies, it becomes increasingly difficult to identify which technologies are
economically viable and how to design and integrate them effectively.
Using large-scale energy system models in Europe, the dissertation shows that solely
relying on Levelized Cost of Storage (LCOS) metrics for technology assessments can
mislead and that traditional system-value methods raise important questions about
how to assess multiple energy storage technologies. Further, the work introduces a
new complementary system-value assessment method called the market-potential
method, which provides a systematic deployment analysis for assessing multiple
storage technologies under competition. However, integrating energy storage in
system models can lead to the unintended storage cycling effect, which occurs in
approximately two-thirds of models and significantly distorts results. The thesis
finds that traditional approaches to deal with the issue, such as multi-stage optimization
or mixed integer linear programming approaches, are either ineffective
or computationally inefficient. A new approach is suggested that only requires
appropriate model parameterization with variable costs while keeping the model
convex to reduce the risk of misleading results.
In addition, to enable energy storage assessments and energy system research around
the world, the thesis extended the geographical scope of an existing European opensource
model to global coverage. The new build energy system model ‘PyPSA-Earth’
is thereby demonstrated and validated in Africa. Using PyPSA-Earth, the thesis
assesses for the first time the system value of 20 energy storage technologies across
multiple scenarios in a representative future power system in Africa. The results offer
insights into approaches for assessing multiple energy storage technologies under
competition in large-scale energy system models. In particular, the dissertation
addresses extreme cost uncertainty through a comprehensive scenario tree and finds
that, apart from lithium and hydrogen, only seven energy storage are optimizationrelevant
technologies. The work also discovers that a heterogeneous storage design
can increase power system benefits and that some energy storage are more important
than others. Finally, in contrast to traditional methods that only consider single
energy storage, the thesis finds that optimizing multiple energy storage options
tends to significantly reduce total system costs by up to 29%.
The presented research findings have the potential to inform decision-making processes
for the sizing, integration, and deployment of energy storage systems in
decarbonized power systems, contributing to a paradigm shift in scientific methodology
and advancing efforts towards a sustainable future
LIPIcs, Volume 251, ITCS 2023, Complete Volume
LIPIcs, Volume 251, ITCS 2023, Complete Volum
Proceedings of SIRM 2023 - The 15th European Conference on Rotordynamics
It was our great honor and pleasure to host the SIRM Conference after 2003 and 2011 for the third time in Darmstadt. Rotordynamics covers a huge variety of different applications and challenges which are all in the scope of this conference. The conference was opened with a keynote lecture given by Rainer Nordmann, one of the three founders of SIRM “Schwingungen in rotierenden Maschinen”. In total 53 papers passed our strict review process and were presented. This impressively shows that rotordynamics is relevant as ever. These contributions cover a very wide spectrum of session topics: fluid bearings and seals; air foil bearings; magnetic bearings; rotor blade interaction; rotor fluid interactions; unbalance and balancing; vibrations in turbomachines; vibration control; instability; electrical machines; monitoring, identification and diagnosis; advanced numerical tools and nonlinearities as well as general rotordynamics. The international character of the conference has been significantly enhanced by the Scientific Board since the 14th SIRM resulting on one hand in an expanded Scientific Committee which meanwhile consists of 31 members from 13 different European countries and on the other hand in the new name “European Conference on Rotordynamics”. This new international profile has also been
emphasized by participants of the 15th SIRM coming from 17 different countries out of three continents. We experienced a vital discussion and dialogue between industry and academia at the conference where roughly one third of the papers were presented by industry and two thirds by academia being an excellent basis to follow a bidirectional transfer what we call xchange at Technical University of Darmstadt. At this point we also want to give our special thanks to the eleven industry sponsors for their great support of the conference. On behalf of the Darmstadt Local Committee I welcome you to read the papers of the 15th SIRM giving you further insight into the topics and presentations
Using hydrological models and digital soil mapping for the assessment and management of catchments: A case study of the Nyangores and Ruiru catchments in Kenya (East Africa)
Human activities on land have a direct and cumulative impact on water and other natural resources within a catchment. This land-use change can have hydrological consequences on the local and regional scales. Sound catchment assessment is not only critical to understanding processes and functions but also important in identifying priority management areas. The overarching goal of this doctoral thesis was to design a methodological framework for catchment assessment (dependent upon data availability) and propose practical catchment management strategies for sustainable water resources management. The Nyangores and Ruiru reservoir catchments located in Kenya, East Africa were used as case studies. A properly calibrated Soil and Water Assessment Tool (SWAT) hydrologic model coupled with a generic land-use optimization tool (Constrained Multi-Objective Optimization of Land-use Allocation-CoMOLA) was applied to identify and quantify functional trade-offs between environmental sustainability and food production in the ‘data-available’ Nyangores catchment. This was determined using a four-dimension objective function defined as (i) minimizing sediment load, (ii) maximizing stream low flow and (iii and iv) maximizing the crop yields of maize and soybeans, respectively.
Additionally, three different optimization scenarios, represented as i.) agroforestry (Scenario 1), ii.) agroforestry + conservation agriculture (Scenario 2) and iii.) conservation agriculture (Scenario 3), were compared. For the data-scarce Ruiru reservoir catchment, alternative methods using digital soil mapping of soil erosion proxies (aggregate stability using Mean Weight Diameter) and spatial-temporal soil loss analysis using empirical models (the Revised Universal Soil Loss Equation-RUSLE) were used. The lack of adequate data necessitated a data-collection phase which implemented the conditional Latin Hypercube Sampling. This sampling technique reduced the need for intensive soil sampling while still capturing spatial variability. The results revealed that for the Nyangores catchment, adoption of both agroforestry and conservation agriculture (Scenario 2) led to the smallest trade-off amongst the different objectives i.e. a 3.6% change in forests combined with 35% change in conservation agriculture resulted in the largest reduction in sediment loads (78%), increased low flow (+14%) and only slightly decreased crop yields (3.8% for both maize and soybeans). Therefore, the advanced use of hydrologic models with optimization tools allows for the simultaneous assessment of different outputs/objectives and is ideal for areas with adequate data to properly calibrate the model. For the Ruiru reservoir catchment, digital soil mapping (DSM) of aggregate stability revealed that susceptibility to erosion exists for cropland (food crops), tea and roadsides, which are mainly located in the eastern part of the catchment, as well as deforested areas on the western side. This validated that with limited soil samples and the use of computing power, machine learning and freely available covariates, DSM can effectively be applied in data-scarce areas. Moreover, uncertainty in the predictions can be incorporated using prediction intervals. The spatial-temporal analysis exhibited that bare land (which has the lowest areal proportion) was the largest contributor to erosion. Two peak soil loss periods corresponding to the two rainy periods of March–May and October–December were identified. Thus, yearly soil erosion risk maps misrepresent the true dimensions of soil loss with averages disguising areas of low and high potential. Also, a small portion of the catchment can be responsible for a large proportion of the total erosion. For both catchments, agroforestry (combining both the use of trees and conservation farming) is the most feasible catchment management strategy (CMS) for solving the major water quantity and quality problems. Finally, the key to thriving catchments aiming at both sustainability and resilience requires urgent collaborative action by all stakeholders. The necessary stakeholders in both Nyangores and Ruiru reservoir catchments must be involved in catchment assessment in order to identify the catchment problems, mitigation strategies/roles and responsibilities while keeping in mind that some risks need to be shared and negotiated, but so will the benefits.:TABLE OF CONTENTS
DECLARATION OF CONFORMITY........................................................................ i
DECLARATION OF INDEPENDENT WORK AND CONSENT ............................. ii
LIST OF PAPERS ................................................................................................. iii
ACKNOWLEDGEMENTS ..................................................................................... iv
THESIS AT A GLANCE ......................................................................................... v
SUMMARY ............................................................................................................ vi
List of Figures......................................................................................................... x
List of Tables........................................................................................................... x
ABBREVIATION..................................................................................................... xi
PART A: SYNTHESIS
1. INTRODUCTION ............................................................................................... 1
1.1 Catchment management ...................................................................................1
1.2 Tools to support catchment assessment and management ..............................4
1.3 Catchment management strategies (CMSs)......................................................9
1.4 Concept and research objectives.......................................................................11
2. MATERIAL AND METHODS................................................................................15
2.1. STUDY AREA ..................................................................................................15
2.1.1. Nyangores catchment ...................................................................................15
2.1.2. Ruiru reservoir catchment .............................................................................17
2.2. Using SWAT conceptual model and land-use optimization ..............................19
2.3. Using soil erosion proxies and empirical models ..............................................21
3. RESULTS AND DISCUSSION..............................................................................24
3.1. Assessing multi-metric calibration performance using the SWAT model...........25
3.2. Land-use optimization using SWAT-CoMOLA for the Nyangores catchment. ..26
3.3. Digital soil mapping of soil aggregate stability ..................................................28
3.4. Spatio-temporal analysis using the revised universal soil loss equation (RUSLE) 29
4. CRITICAL ASSESSMENT OF THE METHODS USED ......................................31
4.1. Assessing suitability of data for modelling and overcoming data challenges...31
4.2. Selecting catchment management strategies based on catchment assessment . 35
5. CONCLUSION AND RECOMMENDATIONS ....................................................36
6. REFERENCES ............................ .....................................................................38
PART B: PAPERS
PAPER I .................................................................................................................47
PAPER II ................................................................................................................59
PAPER III ...............................................................................................................74
PAPER IV ...............................................................................................................8
Advances and Applications of DSmT for Information Fusion. Collected Works, Volume 5
This fifth volume on Advances and Applications of DSmT for Information Fusion collects theoretical and applied contributions of researchers working in different fields of applications and in mathematics, and is available in open-access. The collected contributions of this volume have either been published or presented after disseminating the fourth volume in 2015 in international conferences, seminars, workshops and journals, or they are new. The contributions of each part of this volume are chronologically ordered.
First Part of this book presents some theoretical advances on DSmT, dealing mainly with modified Proportional Conflict Redistribution Rules (PCR) of combination with degree of intersection, coarsening techniques, interval calculus for PCR thanks to set inversion via interval analysis (SIVIA), rough set classifiers, canonical decomposition of dichotomous belief functions, fast PCR fusion, fast inter-criteria analysis with PCR, and improved PCR5 and PCR6 rules preserving the (quasi-)neutrality of (quasi-)vacuous belief assignment in the fusion of sources of evidence with their Matlab codes.
Because more applications of DSmT have emerged in the past years since the apparition of the fourth book of DSmT in 2015, the second part of this volume is about selected applications of DSmT mainly in building change detection, object recognition, quality of data association in tracking, perception in robotics, risk assessment for torrent protection and multi-criteria decision-making, multi-modal image fusion, coarsening techniques, recommender system, levee characterization and assessment, human heading perception, trust assessment, robotics, biometrics, failure detection, GPS systems, inter-criteria analysis, group decision, human activity recognition, storm prediction, data association for autonomous vehicles, identification of maritime vessels, fusion of support vector machines (SVM), Silx-Furtif RUST code library for information fusion including PCR rules, and network for ship classification.
Finally, the third part presents interesting contributions related to belief functions in general published or presented along the years since 2015. These contributions are related with decision-making under uncertainty, belief approximations, probability transformations, new distances between belief functions, non-classical multi-criteria decision-making problems with belief functions, generalization of Bayes theorem, image processing, data association, entropy and cross-entropy measures, fuzzy evidence numbers, negator of belief mass, human activity recognition, information fusion for breast cancer therapy, imbalanced data classification, and hybrid techniques mixing deep learning with belief functions as well
Relatively Absolute : Relative and Absolute Chronologies in the Neolithic of Southeast Europe
Зборник радова на тему апсолутне и релативне хронологије неолитског периода у југоисточној Европи. Географски покрива области од Грчке до Хрватске, а хронолошки период између 7000 и 4500 године пре нове ере. У зборнику су приказани најновији приступи и резултати радиокарбонских анализа и статистички и типолошки модели који побољшавају прецизност резултата
Bridging Micro- and Macro- Evolution In Tropical Fishes
In marine environments, barriers to dispersal can be challenging to identify because they are often cryptic. Unlike terrestrial environments, where a mountain chain that is visible can physically separate two populations of animals, vast masses of water in the ocean make it challenging to pinpoint these barriers. Therefore, the impact of these barriers on the formation of new species in the ocean is still not well understood. While most marine populations have long been considered to be well connected via long-distance dispersal, molecular ecology studies are increasingly unveiling inconspicuous barriers that promote population divergence and ultimately speciation. The advent of genomic techniques that allow the generation of data for thousands of genes has provided an unprecedented opportunity to uncover marine barriers that were previously invisible using more rudimentary tools. This, in turn, has opened new avenues for understanding of how barriers to dispersal affect population connectivity in the marine environment. The overarching goal of my dissertation is to use genome-wide data to look for genetic patterns that correspond to such barriers, and to test for their effect at short-, intermediate- and long-term evolutionary scales, going through a continuum from micro- to macro-evolution, in a time span from thousands to millions of years.
At the short-scale, I examined two controversial cases of species delimitation. Species delimitation is a major question in biology and is essential for adequate management of organismal diversity. The first challenging case involves the red snappers in the Western Atlantic. Red snappers have been traditionally recognized as two separate species based on morphology: Lutjanus campechanus (northern red snapper) and L. purpureus (southern red snapper). However, recent genetic studies using few molecular markers failed to delineate these nominal species, lumping the northern and southern populations into a single species (L. campechanus). To evaluate if the populations of these fish represent one or two species, my project applied ca. 40,000 genome-wide markers of 178 individuals collected throughout the range of the two species and population and species delimitation analyses. Overall, my results supported the isolation and differentiation of these species, a result that confirmed the morphology-based delimitation scenario, highlighting the benefits of using genome-wide data in complex cases of species delimitation (Chapter I, published in Proc. Roy. Soc. B in 2019).
The second study case involves a species complex of silverside fishes (Chirostoma humboltianum group: Atherinidae) in the Central Mexico plateau. The humboltianum group represents a taxonomically-controversial species complex where previous morphological and molecular studies based on a few genes produced conflicting species delineation scenarios. I applied an integrative approach that considered multiple lines of evidence to investigate the species numbers and boundaries comprising this contentious group. I used ca. 33,000 molecular markers for 77 individuals representing the nine nominal species in the group, spanning their distribution range in the central Mexico plateau, in combination with morphologic and ecologic information. My findings are inconsistent with the morphospecies and ecological delimitation scenarios, identifying three to four species. This study provides an atypical example in which genome-wide analyses delineate fewer species than previously recognized on the basis of morphological data alone. It also highlights the influence of geologic history as a main driver of speciation in the group (Chapter II, published in BMC Eco. Evol. B in 2022).
At the intermediate- scale, I evaluated the influence of historical (e.g., geophysical events) and contemporary barriers (e.g., habitat gaps) hindering genetic flow among populations by studying the spatio-temporal phylogenetic concordance of co-distributed lineages. For this study, I investigated the comparative phylogeography of labrisomid blennies in the genus Malacoctenus. I generated data for ca. 28K genome-wide markers that were sequenced from over 500 individuals collected from 38 locations, representing 23 (out of 25) species of Malacoctenus. With this dataset, I assessed the effect of recognized historical (e.g., the rising of the Isthmus of Panama) and contemporary barriers (e.g., sandy gaps) in the Tropical Eastern Pacific (TEP) and the Tropical Atlantic (TA) biogeographic realms. These blennies represent an ideal system to test the effect of such barriers as they are strongly associated with rocky habitats and coral reefs. Therefore, subtle habitat disruptions may lead to genetic isolation. At the micro-evolutionary scale, the observed population structure patterns identified the Sinaloan and Central American breaks as the major breaks in the TEP; and the Bahamas and Eastern Caribbean breaks as key barriers disrupting connectivity in the TA. All in all, the effect of these breaks varies across species, suggesting that species-specific traits (e.g., habitat preference), also greatly influence their dispersal capabilities. My study identified five instances where marine barriers promoted the diversification of independent evolutionary lineages that could potentially represent species complexes. Some of them supported by evidence of population differentiation from previous morphological analyses as well as by my geometric morphometric analyses. Major environmental variables driving population differentiation in the TEP are depth, temperature, chlorophyll altogether with spatial components, while in the TA suspended particle matter also influences diversification.
At the long-term scale, my results suggest that depth is a primary driver of speciation in the TEP, leading to niche divergence between tide pool- and reef-associated clades. In contrast, in the TA, patterns of environmental association appeared more intricate, where depth, temperature, chlorophyll and physical features significantly contributing to speciation in this region. Finally, our time-calibrated analyses at macroevolutionary scales elucidated an Eastern Atlantic origin of the clade followed by an east-to-west dispersal. Although the historical break attributed to the rise of the Isthmus of Panama had a substantial influence on the evolutionary history of the genus, our analyses demonstrate that it did not triggered synchronous cladogenetic events. In summary, by using a combination of population genomics, comparative phylogeography, phylogenomics, seascape genomics, and geometric morphometric approaches, this study highlights major contemporary and historical barriers hindering population connectivity in the TEP and TA biogeographic regions, enhancing our understanding of the forces and processes generating new species in marine systems (Chapter III, to be submitted for publication).
All in all, my thesis highlights that the use of genome-wide data provides unprecedented resolution to unveil patterns of genetic structure, commonly unraveling cryptic diversity, and the opportunity to address species delimitation problems. By uncovering the spatio-temporal genetic patterns of fishes along the evolutionary continuum, my dissertation provides novel insights into the evolutionary and biogeographic history of marine and freshwater Neotropical fishes. Overall, my dissertation not only helps to understand the evolutionary history of the species under study, but more generally, elucidate factors driving evolutionary process in the marine realm, ranging from population-level scales, to speciation, to higher level relationships among groups
Current issues of the management of socio-economic systems in terms of globalization challenges
The authors of the scientific monograph have come to the conclusion that the management of socio-economic systems in the terms of global challenges requires the use of mechanisms to ensure security, optimise the use of resource potential, increase competitiveness, and provide state support to economic entities. Basic research focuses on assessment of economic entities in the terms of global challenges, analysis of the financial system, migration flows, logistics and product exports, territorial development. The research results have been implemented in the different decision-making models in the context of global challenges, strategic planning, financial and food security, education management, information technology and innovation. The results of the study can be used in the developing of directions, programmes and strategies for sustainable development of economic entities and regions, increasing the competitiveness of products and services, decision-making at the level of ministries and agencies that regulate the processes of managing socio-economic systems. The results can also be used by students and young scientists in the educational process and conducting scientific research on the management of socio-economic systems in the terms of global challenges
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