63 research outputs found

    Preliminary experiments with EVA - Serious Games virtual fire drill simulator

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    Fire keeps claiming a large number of victims in building fires. Although there are ways to minimize such events, fire drills are used to train the building occupants for emergency situations, organizing and implement these exercises is a complex task, and sometimes not sucessfull. Moreover, fire drills require the mobilization of some finantial resources and time, and affect the normal functioning of the site where they occur. To overcome the aforementioned issues, computer games have a set of features that might overcome this problem. They offer engagement to their players, keeping them focused, and providing training to real life situations. The game evaluate users, providing them some feedback, making possible for the players to improve their performance. The proposed methodology aims to study the viability of using a game that recreates a fire drill in a 3D environment using Serious Games. The information acquired through the players performance is then used to implement an artificial population. A sample of 20 subjects was selected to test the application. The results are promising, showing that the exercise had a positive impact on users. Moreover, the data acquired was used to demonstrate the possibility of creating an artificial population based on human

    Upravljanje otporno na kvarove modularnim prekidačko-reluktantnim strojem nadahnuto prirodom

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    Fault tolerance is an obligatory feature in safety critical applications (aeronautical, aerospace, medical and military applications, power plants, etc.), where loss of life, environmental disasters, equipment destructions or unplanned downtimes must be avoided. For such applications, a novel bio-inspired motion control system is proposed. All its three components (the switched reluctance machine, the power converter and the control system) are designed to be as fault tolerant as possible. This paper describes all these three fault tolerant components: the bio-inspired control system having self-healing capabilities, the power converter with an extra leg and the fault tolerant modular machine. The theoretical expectations and simulation results are validated by means of laboratory experiments.Otpornost na kvarove je nužnost u sigurnosno kritičnim aplikacijama (aeronautičke, zrakoplovne, medicinske i vojne aplikacije, elektrane itd.), gdje je potrebno izbjeći smrtne slučajeve, prirodne nepogode, uništenje opreme ili neplanirane prekide u radu. Za takve aplikacije, predložen je novi slijedni sustav nadahnut prirodom. Sve tri komponente (prekidačko-reluktantni stroj, pretvarač i sustav upravljanja) su projektirani da budu što je više moguće otporni na kvarove. Ovaj rad opisuje sve tri komponente: sustav upravljanja nadahnut prirodom sa samoliječećim svojstvima, pretvarač s dodatnom granom i modularni stroj otporan na kvarove. Teoretska očekivanja i simulacijski rezultati su provjereni laboratorijskim eksperimentima

    Solving the preference-based conference scheduling problem through domain transformation approach

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    Conference scheduling can be quite a simple and straightforward problem if the number of papers to be scheduled is small.However, the problem can be very challenging and complex if the number of papers is large and various additional constraints need to be satisfied.Conference scheduling with regard to satisfying participants’ preferences can be understood as to generate schedule to minimize the clashes between slots or sessions that participants are interested to attend.Motivated by the current research trend in maximizing participants’ satisfactions, the study looks at the possibility of scheduling papers to sessions without any conflict by considering preferences by participants.In this research, preferences refer to the papers chosen by participants that they would like to attend its’ presentations sessions.Domain Transformation Approach (DTA), which has produced very encouraging results in our previous works, is used in this study to solve preference-based conference scheduling problem. The purpose of utilizing the method is to test the generality and universality of the approach in producing feasible schedule, given a different scheduling problem.The results obtained confirm that DTA efficiently generated feasible schedule which satisfies hard constraints and also fulfills all the preferences.With the generated schedule, all participants are able to attend their sessions of interest.In the future work, additional constraints will be taken into account in optimizing the schedules, for example balancing the number of papers assigned to each timeslot, and minimizing assignment of presenters to different timeslots.Other datasets could also be tested in order to test the generality of the proposed approach

    Estimating the international tourism demand for Egypt : 'an econometric approach'

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    The thesis aims to identify the main factors that significantly affect tourism demand for Egypt. Both time series data and panel data are used to model and forecast tourism demand for Egypt from all origins, as well as three individual regions of origin, including Europe, Arab and the Americas. The methodological and econometric approaches introduced in this thesis proceed from the simple to the more complex structure to obtain more reliable estimation. First, we estimate tourism demand for Egypt using the co-integration and error correction (CI/ECM) approach based on a single equation, followed by using a system of equations approach over the period 1970-2009. All the estimated econometric methods, in addition to two univariate time series methods, are used to generate ex-post forecasting for all the models over the period 2005-2009. The preferred method is used in producing ex-ante forecasting of future tourism demand for Egypt for the period 2010-2014. Panel co-integration techniques are also used to estimate tourism demand models over the period 1980-2009. Finally, the causality relationship between tourism demand and its economic determinants is estimated based on panel data analysis, which may provide more guidance for policy makers in Egypt.The results indicate that tourism demand for Egypt is found to be co-integrated with its fundamental determinants at the 1% significance level, with a high adjustment speed toward the steady state equilibrium. The importance of long-run income for all tourists from different nationalities is affirmed; with an elastic demand for non-Arab tourists. Price is also an important determinant, with a different effect in each originating region. It takes less than unity value for all tourists, except the Arab. Tunisia is found to be the most significant alternative to Egypt, with a complementary effect for Europe and the Americas tourists, but substitutability effect for Arab tourists. Hotel capacity is a significant and positive factor for all nationalities, except the Americas. Globalization is important in all models; it has a positive effect for all non-Arab nationalities. Political instability has a significant and negative effect, with the most effect on the Americas. All the determinants Granger cause tourist arrivals in the long run, but globalization and hotel capacity are of great importance with a bidirectional effect with tourist arrivals. Ex-post forecasting results show that the CI/ECMs outperform the other time series methods and produce highly accurate forecasts. The number of arrivals and nights from all origin markets is likely to increase in absolute terms (2010-2014), but with slower growth than recent trend

    A domain transformation approach for addressing staff scheduling problems

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    Staff scheduling is a complex combinatorial optimisation problem concerning allocation of staff to duty rosters in a wide range of industries and settings. This thesis presents a novel approach to solving staff scheduling problems, and in particular nurse scheduling, by simplifying the problem space through information granulation. The complexity of the problem is due to a large solution space and the many constraints that need to be satisfied. Published research indicates that methods based on random searches of the solution space did not produce good-quality results consistently. In this study, we have avoided random searching and proposed a systematic hierarchical method of granulation of the problem domain through pre-processing of constraints. The approach is general and can be applied to a wide range of staff scheduling problems. The novel approach proposed here involves a simplification of the original problem by a judicious grouping of shift types and a grouping of individual shifts into weekly sequences. The schedule construction is done systematically, while assuring its feasibility and minimising the cost of the solution in the reduced problem space of weekly sequences. Subsequently, the schedules from the reduced problem space are translated into the original problem space by taking into account the constraints that could not be represented in the reduced space. This two-stage approach to solving the scheduling problem is referred to here as a domain-transformation approach. The thesis reports computational results on both standard benchmark problems and a specific scheduling problem from Kajang Hospital in Malaysia. The results confirm that the proposed method delivers high-quality results consistently and is computationally efficient

    Development of Integrated Models for Thermal Management in Hybrid Vehicles

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    [ES] En los últimos años, la industria de la automoción ha hecho un gran esfuerzo para producir sistemas de propulsión más eficientes y menos contaminantes sin menguar su rendimiento. Las nuevas regulaciones impuestas por las autoridades han empujado a la industria hacia la electrificación de los sistemas de propulsión mientras que las tecnologías desarrolladas para el sistema de propulsión convencional, basado en motores de combustión interna alternativos (MCIA), ya no son suficientes. El modelado numérico ha demostrado ser una herramienta indispensable para el diseño, desarrollo y optimización de sistemas de gestión térmica en trenes motrices electrificados, ahorrando costes y reduciendo el tiempo de desarrollo. La gestión térmica en los MCIA siempre ha sido importante para mejorar el consumo, las emisiones y la seguridad. Sin embargo, es todavía más importante en los sistemas de propulsión híbridos, a causa de la complejidad del sistema y al funcionamiento intermitente del MCIA. Además, los trenes motrices electrificados tienen varias fuentes de calor (es decir, MCIA, batería, máquina eléctrica) con diferentes requisitos de funcionamiento térmico. El objetivo principal de este trabajo ha sido desarrollar modelos térmicos para estudiar la mejora de los sistemas de gestión térmica en sistemas de propulsión electrificados (es decir, vehículo híbrido), estudiando y cuantificando la influencia de diferentes estrategias en el rendimiento, la seguridad y la eficiencia de los vehículos. La metodología desarrollada en este trabajo consistió tanto en la realización de experimentos como en el desarrollo de modelos numéricos. De hecho, se llevó a cabo una extensa campaña experimental para validar los diferentes modelos del tren motriz electrificado. Los datos obtenidos de las campañas experimentales sirvieron para calibrar y validar los modelos así como para corroborar los resultados obtenidos por los estudios numéricos. En primer lugar, se estudiaron las diferentes estrategias de gestión térmica de manera independiente para cada componente del tren motriz. Para el MCIA se estudió el uso de nanofluidos, el aislamiento del colector y puertos de escape, así como el cambio de volumen de sus circuitos hidráulicos. De igual forma, se evaluó el impacto de diferentes estrategias para la mejora térmica de las baterías. Además, el modelo de máquina eléctrica se utilizó para desarrollar pruebas experimentales que emulaban el daño térmico producido en ciclos reales de conducción. En segundo lugar, los modelos de tren motriz se integraron utilizando un estándar de co-simulación para evaluar el impacto de un sistema de gestión térmica integrado. Finalmente, se implementó un nuevo control del sistema de gestión de energía para evaluar el impacto de considerar el estado térmico del MCIA al momento de decidir la distribución de potencia del vehículo híbrido. Los resultados han demostrado que el uso de nanofluidos tiene un impacto muy limitado tanto en el MCIA como en el comportamiento térmico de la batería. Además, también mostraron que al reducir el volumen de refrigerante en un 45 %, la reducción en el tiempo de calentamiento del MCIA y el consumo de combustible en comparación con el caso baso fue del 7 % y del 0.4 %, respectivamente. Además, para condiciones de frio (7ºC), el impacto fue todavía mayor, obteniendo una reducción del tiempo de calentamiento y del consumo de combustible del 13 % y del 0.5 % respectivamente. Por otro lado, los resultados concluyeron que durante el calentamiento del MCIA, el sistema integrado de gestión térmica mejoró el consumo de energía en un 1.74 % y un 3 % para condiciones de calor (20ºC) y frío (-20ºC), respectivamente. Esto se debe al hecho que el sistema de gestión térmica integrado permite evitar la caída de temperatura del MCIA cuando el sistema de propulsión está en manera eléctrica pura.[CA] En els últims anys, la indústria de l'automoció ha fet un gran esforç per a produir sistemes de propulsió més eficients i menys contaminants sense minvar el seu rendiment. Les noves regulacions imposades per les autoritats han espentat a la indústria cap a l'electrificació dels sistemes de propulsió mentre que les tecnologies desenvolupades per al sistema de propulsió convencional, basat en motors de combustió interna alternatius (MCIA), ja no són suficients. El modelatge numèric ha demostrat ser una eina indispensable per al disseny, desenvolupament i optimització de sistemes de gestió tèrmica en trens motrius electrificats, estalviant costos i reduint el temps de desenvolupament. La gestió tèrmica en els MCIA sempre ha sigut important per a millorar el consum, les emissions i la seguretat. No obstant això, és encara més important en els sistemes de propulsió híbrids, a causa de la complexitat del sistema i al funcionament intermitent del MCIA. A més, els trens motrius electrificats tenen diverses fonts de calor (és a dir, MCIA, bateria, màquina elèctrica) amb diferents requisits de funcionament tèrmic. L'objectiu principal d'aquest treball va ser desenvolupar models tèrmics per a estudiar la millora dels sistemes de gestió tèrmica en sistemes de propulsió electrificats (és a dir, vehicle híbrid), estudiant i quantificant la influència de diferents estratègies en el rendiment, la seguretat i l'eficiència dels vehicles. La metodologia desenvolupada en aquest treball va consistir tant en la realització d'experiments com en el desenvolupament de models numèrics. De fet, es va dur a terme una extensa campanya experimental per a validar els diferents models del tren motriu electrificat. Les dades obtingudes de les campanyes experimentals van servir per a calibrar i validar els models així com per a corroborar els resultats obtinguts pels estudis numèrics. En primer lloc, es van estudiar les diferents estratègies de gestió tèrmica de manera independent per a cada component del tren motriu. Per al MCIA es va estudiar l'us de nanofluids, l'aïllament del col·lector i ports d'eixida així com el canvi de volum dels seus circuits hidràulics. D'igual forma, es va avaluar l'impacte de diferents estratègies per a la millora tèrmica de les bateries. A més, el model de màquina elèctrica es va utilitzar per a desenvolupar proves experimentals que emulaven el mal tèrmic produït en cicles reals de conducció. En segon lloc, els models de tren motriu es van integrar utilitzant un estàndard de co-simulació per a avaluar l'impacte d'un sistema de gestió tèrmica integrat. Finalment, es va implementar un nou control del sistema de gestió d'energia per a avaluar l'impacte de considerar l'estat tèrmic del MCIA al moment de decidir la distribució de potència del vehicle híbrid. Els resultats han demostrat que l'us de nanofluids té un impacte molt limitat tant en el MCIA com en el comportament tèrmic de la bateria. A més, també van mostrar que en reduir el volum de refrigerant en un 45 %, la reducció en el temps de calfament del MCIA i el consum de combustible en comparació amb el cas base va ser del 7 % i del 0.4 %, respectivament. A més, per a condicions de fred (-7ºC), l'impacte va ser encara major, obtenint una reducció del temps de calfament i del consum de combustible del 13 % i del 0.5 % respectivament. D'altra banda, els resultats van concloure que durant el calfament del MCIA, el sistema integrat de gestió tèrmica va millorar el consum d'energia en un 1.74 % i un 3 % per a condicions de calor (20ºC) i fred (-20ºC), respectivament. Això es deu al fet que el sistema de gestió tèrmica integrat permet evitar la caiguda de temperatura del MCIA quan el sistema de propulsió està en manera elèctrica pura.[EN] In recent years, the automotive industry has made a great effort to produce more efficient and less polluting propulsion systems without diminishing their performance. The new regulations imposed by the authorities have pushed the industry towards the electrification of powertrains while, technologies developed for the conventional propulsion system based on alternative internal combustion engines (ICEs), are no longer sufficient. Numerical modeling has proven to be an indispensable tool for the design, development and optimization of thermal management systems in electrified powertrains, saving costs and reducing development time. Thermal management in ICEs has always been important for improving consumption, emissions and safety. However, it is even more important in hybrid powertrains, due to the complexity of the system and the intermittent operation of the ICE. In addition, electrified powertrains have various heat sources (i.e., ICE, battery, Electric machine) with different thermal operating requirements. The main objective of this work was to develop thermal models to study the improvement of thermal management systems in electrified powertrains (i.e., hybrid electric vehicle), shedding light and quantifying the influence of different strategies on performance, safety and efficiency of the vehicles. The methodology developed in this paper consisted both in carrying out experiments and in developing numerical models. In fact, an extensive experimental campaign was carried out to validate the various models of the electrified powertrain. The data obtained from the experimental campaigns served to calibrate and validate the models as well as to corroborate the results obtained by the numerical studies. Firstly, the different thermal management strategies were studied independently for each component of the powertrain. For the ICE, the use of nanofluids, insulation of exhaust manifold and ports as well as the volume change of its hydraulic circuits were studied. Similarly, the impact of different strategies for the thermal improvement of batteries was evaluated. Furthermore, the electric machine model was used for developing experimental tests which emulated the thermal damage produced in real driving cycles. Secondly, the powertrain models were integrated using a co-simulation standard to assess the impact of an integrated thermal management system. Finally, a new control energy management system was implemented to assess the impact of considering the ICE thermal state when deciding the power split of the hybrid vehicle. The results have shown that the use of nanofluids has a very limited impact on both the ICE and the battery's thermal behaviour. In addition, they also showed that by reducing the volume of coolant by 45 %, the reduction in ICE warm up time and fuel consumption compared to the base case were 7 % and 0.4 %, respectively. In addition, for cold conditions (-7ºC), the impact was even greater, obtaining a reduction in warm up time and fuel consumption of 13 % and 0.5 % respectively. On the other hand, the results concluded that during the warming of ICE, the integrated thermal management system improved energy consumption by 1.74 % and 3 % for warm (20ºC) and cold (-20ºC) conditions, respectively. This is because the integrated TMS makes it possible to prevent the ICE temperature drop when the powertrain is in pure electric mode. Finally, significant gains during Worldwide harmonized Light vehicles Test Cycles (WLTC) and Real Driving Emissions (RDE) cycles were observed when the ICE thermal state was chosen when deciding the power distribution.The author would like to sincerely acknowledge the founding support pro- vided by Conselleria de Innovación, Universidades, Ciencia y Sociedad Digital in the framework of the Ayuda Predoctoral GVA. (ACIF/2020/234). Additionally the author would also acknowledge the support provided by Renault S.A.S.Dreif Bennany, A. (2023). Development of Integrated Models for Thermal Management in Hybrid Vehicles [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/19406

    Powertrain Systems for Net-Zero Transport

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    The transport sector continues to shift towards alternative powertrains, particularly with the UK Government’s announcement to end the sale of petrol and diesel passenger cars by 2030 and increasing support for alternatives. Despite this announcement, the internal combustion continues to play a significant role both in the passenger car market through the use of hybrids and sustainable low carbon fuels, as well as a key role in other sectors such as heavy-duty vehicles and off-highway applications across the globe. Building on the industry-leading IC Engines conference, the 2021 Powertrain Systems for Net-Zero Transport conference (7-8 December 2021, London, UK) focussed on the internal combustion engine’s role in Net-Zero transport as well as covered developments in the wide range of propulsion systems available (electric, fuel cell, sustainable fuels etc) and their associated powertrains. To achieve the net-zero transport across the globe, the life-cycle analysis of future powertrain and energy was also discussed. Powertrain Systems for Net-Zero Transport provided a forum for engine, fuels, e-machine, fuel cell and powertrain experts to look closely at developments in powertrain technology required, to meet the demands of the net-zero future and global competition in all sectors of the road transportation, off-highway and stationary power industries

    Conifers

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    Conifers include a wide range of species that are spread all over the world. These species have wide diversity, variable stand structures ranging from monospecific monocohort to multispecific multicohort, and produce an assortment of products and services, the most frequent of which is timber. This book is a collection of contributions, both reviews and research studies, from different fields and perspectives on the management, regeneration, growth, diversity, and production of conifer stands. The book also addresses the effect of wildfires on conifer ecosystems and respiratory allergies to conifers

    Accurate Battery Modelling for Control Design and Economic Analysis of Lithium-ion Battery Energy Storage Systems in Smart Grid

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    Adoption of lithium-ion battery energy storage systems (Li-ion BESSs) as a flexible energy source (FES) has been rapid, particularly for active network management (ANM) schemes to facilitate better utilisation of inverter based renewable energy sources (RES) in power systems. However, Li-ion BESSs display highly nonlinear performance characteristics, which are based on parameters such as state of charge (SOC), temperature, depth of discharge (DOD), charge/discharge rate (C-rate), and battery-aging conditions. Therefore, it is important to include the dynamic nature of battery characteristics in the process of the design and development of battery system controllers for grid applications and for techno-economic studies analyzing the BESS economic profitability. This thesis focuses on improving the design and development of Li-ion BESS controllers for ANM applications by utilizing accurate battery performance models based on the second-order equivalent-circuit dynamic battery modelling technique, which considers the SOC, C-rate, temperature, and aging as its performance affecting parameters. The proposed ANM scheme has been designed to control and manage the power system parameters within the limits defined by grid codes by managing the transients introduced due to the intermittence of RESs and increasing the RES penetration at the same time. The validation of the ANM scheme and the effectiveness of controllers that manage the flexibilities in the power system, which are a part of the energy management system (EMS) of ANM, has been validated with the help of simulation studies based on an existing real-life smart grid pilot in Finland, Sundom Smart Grid (SSG). The studies were performed with offline (short-term transient-stability analysis) and real-time (long-term transient analysis) simulations. In long-term simulation studies, the effect of battery aging has also been considered as part of the Li-ion BESS controller design; thus, its impact on the overall power system operation can be analyzed. For this purpose, aging models that can determine the evolving peak power characteristics associated with aging have been established. Such aging models are included in the control loop of the Li-ion BESS controller design, which can help analyse battery aging impacts on the power system control and stability. These analyses have been validated using various use cases. Finally, the impact of battery aging on economic profitability has been studied by including battery-aging models in techno-economic studies.Aurinkosähköjärjestelmien ja tuulivoiman laajamittainen integrointi sähkövoimajärjestelmän eri jännitetasoille on lisääntynyt nopeasti. Uusiutuva energia on kuitenkin luonteeltaan vaihtelevaa, joka voi aiheuttaa nopeita muutoksia taajuudessa ja jännitteessä. Näiden vaihteluiden hallintaan tarvitaan erilaisia joustavia energiaresursseja, kuten energiavarastoja, sekä niiden tehokkaan hyödyntämisen mahdollistaviea älykkäitä ja aktiivisia hallinta- ja ohjausjärjestelmiä. Litiumioniakkuihin pohjautuvien invertteriliitäntäisten energian varastointijärjestelmien käyttö joustoresursseina aktiiviseen verkonhallintaan niiden pätö- ja loistehon ohjauksen avulla on lisääntynyt nopeasti johtuen niiden kustannusten laskusta, modulaarisuudesta ja teknisistä ominaisuuksista. Litiumioniakuilla on erittäin epälineaariset ominaisuudet joita kuvaavat parametrit ovat esimerkiksi lataustila, lämpötila, purkaussyvyys, lataus/ purkausnopeus ja akun ikääntyminen. Akkujen ominaisuuksien dynaaminen luonne onkin tärkeää huomioida myös akkujen sähköverkkoratkaisuihin liittyvien säätöjärjestelmien kehittämisessä sekä teknis-taloudellisissa kannattavuusanalyyseissa. Tämä väitöstutkimus keskittyy ensisijaisesti aktiiviseen verkonhallintaan käytettävien litiumioniakkujen säätöratkaisuiden parantamiseen hyödyntämällä tarkkoja, dynaamisia akun suorituskykymalleja, jotka perustuvat toisen asteen ekvivalenttipiirien akkumallinnustekniikkaan, jossa otetaan huomioon lataustila, lataus/purkausnopeus ja lämpötila. Työssä kehitetyn aktiivisen verkonhallintajärjestelmän avulla tehtävät akun pätö- ja loistehon ohjausperiaatteet on validoitu laajamittaisten simulointien avulla, esimerkiksi paikallista älyverkkopilottia Sundom Smart Gridiä simuloimalla. Simuloinnit tehtiin sekä lyhyen aikavälin offline-simulaatio-ohjelmistoilla että pitkän aikavälin simulaatioilla hyödyntäen reaaliaikasimulointilaitteistoa. Pitkän aikavälin simulaatioissa akun ikääntymisen vaikutus otettiin huomioon litiumioniakun ohjauksen suunnittelussa jotta sen vaikutusta sähköjärjestelmän kokonaistoimintaan voitiin analysoida. Tätä tarkoitusta varten luotiin akun ikääntymismalleja, joilla on mahdollista määrittää akun huipputehon muutos sen ikääntyessä. Akun huipputehon muutos taas vaikuttaa sen hyödynnettävyyteen erilaisten pätötehon ohjaukseen perustuvien joustopalveluiden tarjoamiseen liittyen. Lisäksi väitöstutkimuksessa tarkasteltiin akkujen ikääntymisen vaikutusta niiden taloudelliseen kannattavuuteen sisällyttämällä akkujen ikääntymismalleja teknis-taloudellisiin tarkasteluihin.fi=vertaisarvioitu|en=peerReviewed
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