Analysis and optimization of energy usage in Supermarkets

The thesis performed in this research is focused on a particular type of energy system, energy systems in supermarkets. As supermarkets are high-energy using buildings, their energy system optimization has been investigated in recent years, with the main focus in the refrigeration system, which can take up to 50% of the total energy of the supermarket. However, the complexity and interconnections of the different systems increase the difficulty of the task. The aim of this work is to contribute in SuperSmart project, an EU project which main objective is to reduce the impact of the supermarket sector overall Europe, through the development of an ecolabel criteria. To simulate the energy use in supermarkets, CyberMart software is bring forward. This tool is used both to determine the parameters which have a higher impact in the supermarket energy system and perform energy representation based on those parameters. Finally, the design of the most energy efficient store is also presented. According to CyberMart, some of the most determinant parameters in the supermarket energy system are refrigeration capacities, plug in cabinets used, lights power, heating system technologies used and whether the cabinets are covered or not. Using some of these parameters plus other important characteristics from the store, two energy representations are performed. The linear energy representation provides the increase or decrease of kWh per each parameter, enabling supermarkets owners to compare different parameters within the global system. These representations, which distinguish between heat recovery and floating condensing technologies, conclude that the most important parameters in the global system are the temperature inside at winter and the refrigeration capacity. However, some unreasonable events appear, like the decline of electricity demand when the height of the building increases or the drop of heat demand with the rise of opening hours. These facts occur due to the high complexity of the global system, implying different connections between the sub-systems within CyberMart. Concerning the most energy efficient store located in Stockholm, the obtained results show the most energy efficient supermarket is composed by CO2 refrigeration and heating systems, and a R410_A air conditioning system. The optimal electricity use of each establishment size from large to small area is 382, 394, 390 and 281 kWh/m2*year respectively, with the highest values obtained in Supermarkets and Discount stores, due to their higher rate of refrigeration power per store area

Numerical Implementation of a Critical State Model for Soft Rocks

This paper details the basic tasks for the numerical implementation of a simple elasto-plastic critical state model for bonded materials (i.e. soft rocks-hard soils) into the finite element program SNAC developed at the University of Newcastle in Australia. The first task described focusses on the derivation of the incremental constitutive relationships used to represent the mechanical response of a bonded/cemented material under saturated conditions. The second task presents how these stress-strain relations can be numerically integrated using an explicit substepping scheme with automatic error control. The third task concentrates on the verification of the substepping algorithm proposed. The model used to represent the saturated mechanical response of a bonded material combines the modified Cam clay with the constitutive relationships for cemented materials proposed in Gens & Nova (1993), but incorporates some flexibility on the degradation law adopted. The role of suction and other relevant aspects of unsaturated behaviour are also discussed at the end of the paper

Study of a Dynamic Cooperative Trading Queue Routing Control Scheme for Freeways and Facilities with Parallel Queues

This article explores the coalitional stability of a new cooperative control policy for freeways and parallel queuing facilities with multiple servers. Based on predicted future delays per queue or lane, a VOT-heterogeneous population of agents can agree to switch lanes or queues and transfer payments to each other in order to minimize the total cost of the incoming platoon. The strategic interaction is captured by an n-level Stackelberg model with coalitions, while the cooperative structure is formulated as a partition function game (PFG). The stability concept explored is the strong-core for PFGs which we found appropiate given the nature of the problem. This concept ensures that the efficient allocation is individually rational and coalitionally stable. We analyze this control mechanism for two settings: a static vertical queue and a dynamic horizontal queue. For the former, we first characterize the properties of the underlying cooperative game. Our simulation results suggest that the setting is always strong-core stable. For the latter, we propose a new relaxation program for the strong-core concept. Our simulation results on a freeway bottleneck with constant outflow using Newell's car-following model show the imputations to be generally strong-core stable and the coalitional instabilities to remain small with regard to users' costs.Comment: 3 figures. Presented at Annual Meeting Transportation Research Board 2018, Washington DC. Proof of conjecture 1 pendin

Influence of Mechanical Yielding on Predictions of Saturation: The Saturation Line

It is now well accepted that the mechanical and the water retention behaviour of a soil under unsaturated conditions are coupled and, that such coupling, should be incorporated into a constitutive model for a realistic representation of soil’s response. In existing models, the influence of the mechanical behaviour on the water retention is often represented by a shift of the main wetting retention curve to higher values of matric suction (the difference between pore air and pore water pressures) when the specific volume decreases. This means that any variation of total volumetric strains of compression (whether these are elastic or elasto-plastic) will result in a shift of the main wetting and drying curves to the right, when these curves are represented in the water retention plane. This shift of the main water retention curves, however, should not only influence the unsaturated stress states as often described in the literature, it should also have some impact on the saturated stress states and, more specifically, on the predictions of de-saturation (air-entry point) and saturation (air-exclusion point). From a modelling point of view, it is advantageous to represent this influence through the plastic component of volumetric strain of compression only because, in this way, a consistent representation of the mechanical behaviour for both unsaturated and saturated states can be naturally achieved. This and other advantages resulting from this singular approach are demonstrated in the paper in the context of the Glasgow Coupled Model (GCM)

Utilising content marketing metrics and social networks for academic visibility

There are numerous assumptions on research evaluation in terms of quality and relevance of academic contributions. Researchers are becoming increasingly acquainted with bibliometric indicators, including; citation analysis, impact factor, h-index, webometrics and academic social networking sites. In this light, this chapter presents a review of these concepts as it considers relevant theoretical underpinnings that are related to the content marketing of scholars. Therefore, this contribution critically evaluates previous papers that revolve on the subject of academic reputation as it deliberates on the individual researchers’ personal branding. It also explains how metrics are currently being used to rank the academic standing of journals as well as higher educational institutions. In a nutshell, this chapter implies that the scholarly impact depends on a number of factors including accessibility of publications, peer review of academic work as well as social networking among scholars.peer-reviewe

The importance of seasonality at different levels of ecological organization in the marine ecosystem of the Northwestern Mediterranean Sea

[eng] From an oceanographic perspective, seasonality has been widely studied, and abundant research exists about low trophic level organisms such as phytoplankton and zooplankton. Nevertheless, at a regional scale, this information is not always homogenous and certain areas lack longer time series to track seasonal cycles. This knowledge gap is emphasized as one moves to higher trophic level organisms, whose studies tend to focus on single seasons or inter-annual variation rather than on seasonal changes and intra-annual dynamics. This Ph.D. thesis aims to broaden the knowledge about the marine ecosystem of the Northwestern Mediterranean Sea incorporating the importance of seasonality in key ecological processes, such as body condition, fitness, spatial distribution, and trophic ecology of marine species, and, finally, the structure and functioning of marine food webs. Seasonality is approached at different levels of the marine community, including the demersal component focusing on commercially important species of fish (Merluccius merluccius, Lophius budegassa, Lophius piscatorius, Mullus barbatus), crustaceans (Liocarcinus depurator, Squilla mantis) and cephalopods (Illex coindetii, Eledone cirrhosa), the pelagic component targeting the most abundant and commercially important small pelagic fish species (Sardina pilchardus and Engraulis encrasicolus), and at the ecosystem level using system indicators. To attain these objectives, various methodological approaches have been combined, such as species distribution models, stable isotopes analysis, bayesian isotope mixing isotope models, analysis of biometrical/biophysical parameters (Kn, GSI, fat content), generalized additive models and ecosystem modelling. Results show seasonal variations in species distribution with species-specific patterns in the case of demersal species. Bathymetry, temperature and fishing effort are important drivers explaining biomass spatial distribution of these species. European hake is further studied in one of the chapters, and the predicted posterior mean weight distribution also presents spatial differences between winter and summer. Ontogenetic and seasonal variations are also detected in the diet of this species. Spatial and seasonal variations in fitness are found at the local scale for European sardines and anchovies. These changes are mostly explained by environmental variables while spatial and seasonal factors are also important. Moreover, trophic variables also contributed to the species dynamics, suggesting that variations in prey abundance, composition and quality can impact their fitness. At the ecosystem level, we investigate changes in indicators of ecosystem structure and functioning when using seasonal input data vs annual averages in marine ecosystem models for the characterization of our study area. We find several indicators showing significant variations in ecosystem structure and energy transfer. Overall, the findings of this Ph.D. show seasonal variation at different levels of biological organization and in various ecological processes, which highlights the relevance of seasonality in the marine realm, specifically in the Northwestern Mediterranean Sea. Therefore, we can conclude that considering seasonality in ecological studies can provide complementary insights into our understanding of species biological and ecological dynamics, which cascades up to the knowledge about ecosystem structure and functioning.[spa] Desde una perspectiva oceanográfica y climatológica, la estacionalidad se ha estudiado ampliamente y existen múltiples investigaciones desarrolladas con organismos situados en niveles tróficos bajos, como el fitoplancton y el zooplancton. Sin embargo, a escala regional, esta información no siempre es homogénea y algunas zonas carecen de series temporales largas. Esta laguna de conocimiento se acentúa a medida que se avanza hacia organismos de nivel trófico superior. Esta tesis pretende mejorar el conocimiento sobre el ecosistema marino del mar Mediterráneo noroccidental investigando el efecto de la estacionalidad en algunos procesos ecológicos clave, como la condición corporal, la distribución espacial y la ecología trófica de las especies, así como en la estructura y el funcionamiento de las redes tróficas marinas. La estacionalidad se aborda a distintos niveles de la comunidad marina, incluyendo el componente demersal (especies de peces, crustáceos y cefalópodos), pelágico (la sardina y el boquerón) y a nivel de ecosistema. Para alcanzar estos objetivos, se han combinado diversos enfoques metodológicos (e.g. modelos de distribución de especies, análisis de isótopos estables, análisis de parámetros biométricos/biofísico y modelización de ecosistemas). Para las especies demersales, los resultados muestran variaciones estacionales en su distribución espacial, y la batimetría, la temperatura y el esfuerzo pesquero aparecen como importantes impulsores. La merluza europea se estudia con más detalle en uno de los capítulos y se detectan variaciones ontogenéticas y estacionales en la dieta de esta especie. En el caso de la sardina y el boquerón, se observan variaciones espaciales y estacionales en la condición a escala local. Estos cambios se explican principalmente por variables ambientales y los factores espaciales y estacionales, pero las variables tróficas también contribuyen. A nivel de ecosistema, investigamos los cambios en los indicadores de estructura y funcionamiento de los ecosistemas al utilizar datos de entrada estacionales, frente a medias anuales. Encontramos varios indicadores que muestran variaciones significativas en la estructura del ecosistema y la transferencia de energía. En general, los resultados de esta tesis muestran una variación estacional en diferentes niveles de organización biológica y en varios procesos ecológicos, lo que pone de manifiesto la relevancia de la estacionalidad en el mar Mediterráneo noroccidental. Se concluye que considerar la estacionalidad en los estudios ecológicos puede aportar conocimientos complementarios a la comprensión de la dinámica biológica y ecológica de las especies, y a la estructura y el funcionamiento de los ecosistemas marinos

Security in networks of unmanned aerial vehicles for surveillance with an agent-based approach inspired by the principles of blockchain

Unmanned aerial vehicles (UAVs) can support surveillance even in areas without network infrastructure. However, UAV networks raise security challenges because of its dynamic topology. This paper proposes a technique for maintaining security in UAV networks in the context of surveillance, by corroborating information about events from different sources. In this way, UAV networks can conform peer-to-peer information inspired by the principles of blockchain, and detect compromised UAVs based on trust policies. The proposed technique uses a secure asymmetric encryption with a pre-shared list of official UAVs. Using this technique, the wrong information can be detected when an official UAV is physically hijacked. The novel agent based simulator ABS-SecurityUAV is used to validate the proposed approach. In our experiments, around 90% of UAVs were able to corroborate information about a person walking in a controlled area, while none of the UAVs corroborated fake information coming from a hijacked UAV