Transfer Learning Techniques for the Lithium-Ion Battery State of Charge Estimation

State of Charge (SOC) estimation is vital for battery management systems (BMS), impacting battery efficiency and lifespan. Accurate SOC estimation is challenging due to battery complexity and limited data for training Machine Learning based models. Transfer learning (TL) leverages pre-trained models, reducing training time and improving generalization in SOC estimation. In this paper, 8 different transfer learning techniques are examined, which were applied in four different models (LSTM, GRU, BiLSTM, and BiGRU) for SOC estimation. These transfer learning techniques have been applied to three datasets for re-training the models and results have been compared with the same models defined by Bayesian Hyperparameter Optimization. The TL4 and TL5 techniques consistently stood out as among the most efficient in both accuracy and computational time

Using the Process Digital Twin as a tool for companies to evaluate the Return on Investment of manufacturing automation

The fourth industrial revolution is gaining momentum, but still lacks full realization. Several studies suggest that many companies around the world have begun the digital transformation undertaking, but most are still far from full adoption and yet fail to see the full economic potential, being stuck in what has been called "pilot purgatory”. Digitalization is largely recognized as an accelerator and enabler for full automation in manufacturing, but companies are still struggling to assess the return on investment and the impact on operational performance indicators. Therefore, companies, especially SMEs characterized by dynamic, high-value, high-mix, and low-volume contexts, are reluctant to invest further. By incorporating simulation, data analytics and behavioral models, digital twins may also be used to support automation solutions ramp-up, demonstrate their impact evaluation, usage scenarios, eliminating the need for physical prototypes, reducing development time, and improving quality. Few forward-thinking companies are pursuing the digital transformation path, while the majority are clipping the wings of a transformation that is essential for a sustainable manufacturing. This paper describes a theoretical approach to exploit the digital twin technology to gather insights towards a realistic economical assessment of full automation solutions, to back and encourage investments to realize the potential of the digital manufacturing transformation. The approach is being tested under the European Union’s Horizon 2020 research and innovation program under grant agreement No. 958363, which provides an opportunity to assess how the various components of the method are constructed, how complex they are, and what level of effort is required, using a practical example

A new method to retrieve the real part of the equivalent refractive index of atmospheric aerosols

This document is the Accepted Manuscript version of the following article: S. Vratolis, et al, ‘A new method to retrieve the real part of the equivalent refractive index of atmospheric aerosols’, Journal of Aerosol Science, Vol. 117: 54-62, March 2018. Under embargo until 29 December 2019. The final, published version is available online at DOI: https://doi.org/10.1016/j.jaerosci.2017.12.013.In the context of the international experimental campaign Hygroscopic Aerosols to Cloud Droplets (HygrA-CD, 15 May to 22 June 2014), dry aerosol size distributions were measured at Demokritos station (DEM) using a Scanning Mobility Particle Sizer (SMPS) in the size range from 10 to 550 nm (electrical mobility diameter), and an Optical Particle Counter (OPC model Grimm 107 operating at the laser wavelength of 660 nm) to acquire the particle size distribution in the size range of 250 nm to 2.5 μm optical diameter. This work describes a method that was developed to align size distributions in the overlapping range of the SMPS and the OPC, thus allowing us to retrieve the real part of the aerosol equivalent refractive index (ERI). The objective is to show that size distribution data acquired at in situ measurement stations can provide an insight to the physical and chemical properties of aerosol particles, leading to better understanding of aerosol impact on human health and earth radiative balance. The resulting ERI could be used in radiative transfer models to assess aerosol forcing direct effect, as well as an index of aerosol chemical composition. To validate the method, a series of calibration experiments were performed using compounds with known refractive index (RI). This led to a corrected version of the ERI values, (ERICOR). The ERICOR values were subsequently compared to model estimates of RI values, based on measured PM2.5 chemical composition, and to aerosol RI retrieved values by inverted lidar measurements on selected days.Peer reviewe

BIM-embedded life cycle carbon assessment of RC buildings using optimised structural design alternatives

The implications of optimised structural designs in the life cycle carbon performance of buildings have been systematically overlooked in previous studies. The paper addresses this common limitation offering an integrated sustainable structural analysis at building level. To achieve this, a BIM-embedded approach was established utilising embodied carbon metrics and results from heuristic structural optimisation. A real building scenario was used to test the proposed approach in the context of multi-storey reinforced concrete (RC) buildings. Results show how the building life cycle performance is affected by the use of structurally optimised designs. The structural floors in particular, not only cover the largest proportion of the embodied carbon in the structure but they are also responsible for a large proportion of the carbon emissions of the tested building elements. The results obtained in this paper justified the need for more comprehensive efforts in the design optimisation of RC floors. Overall, it is suggested that the unclear interpretation of the optimisation outputs would result in the selection of structural designs that could compromise the buildings carbon performance

User Rofde Identification in Future Mobile Telecommunications Systems

Nevertheless, researchers are working for the specification of the Universal Mobile Telecommunications System (UMTS), which will be a third-generation system for mobile telecommunications. The UMTS [3] will provide a wide range of telecommunication services to a very large number of Mobile Users (MUS). Services highly comparable to those offered by fixed networks will be available via various Mobile Terminals (MTs). The UMTS will be a multi-operator system and will consist of a range of sub-networks, providing userswith access to different environments, according to the entitlement of the subscriptionswith which they are associated. As a user moves between sub-networks during a call, handover functions from one environment to another may take place [4]. Each of these environments has different technical and economic constraints and will require different solutions. In addition, the UMTS radio access point must be able to connect to or cooperate with fixed networks and be capable of operating as a stand-alone network for operation in non-B-ISDN environments, although itsintegrationwithB-ISDNisanobjectivefor UMTS. Other critical aspects of UMTS are the techniques used to store and manipulate the large amount of information involved, and the intelligence needed in order to control calls and cope with user and terminal mobility. In order to make use of a service, a UMTS user will be able to register on an MT for this particular service [5]. Since user registrations will be performed on a per service basis, a user may be registered on more than one MT for different services. Moreover, some types of UMTS terminals will support multiple user registrations,' but only one of the registered users will be allowed to make use of the terminal at a time. The UMTS will also support Universal Personal Telecommunications (UPT), which means that UPT users will be able to register onto (one or more) UMTS terminals in order to make and accept calls. The ability of a user to roam into the various UMTS environments and make use of the resources and services via different terminals will be checked every time this user enters an environment and/or uses resources and services. This means that an information entity must exist for every user so as to be retrieved every time such achecking is required. This user-related information entity is called the UMTS User Profile (UUP). The UUP is stored in the UMTS Distributed Data Base (UMTS DDB) and can be accessed from every point in the network.2 Management operations on a particular user profile can b e performed only by authorized UMTS operators and possibly by the subscriber concemedorbyauser authorizedbythissubscriber. A U U P includes user authentication information, service access information, access domain information, user charging and accounting information, etc. This article discusses the UMTS user profile identification issues. The authors introduce first the concept of user profile and the UMTS entities related to it. Then, the user profile is described and its management requirements are discussed followed by the description of two scenarios proposed for the user profile identification. Finally, the authors give a comparison of the two scenarios and their concluding remarks. The study of the impact of the proposed scenarios upon UMTS operators, subscribers, users, and mobile terminals is beyond the authors' intent for the scope of this article. Entities Related to the UMTS User Profile efore introducing the UMTS User Profile, we B attempt to identify a number of UMTS entities related to this concept

Automated specification of steel reinforcement to support the optimisation of RC floors

A Building Information Modelling (BIM)-enabled computational approach was presented in this paper for the automated specification of steel reinforcement to support the optimisation of reinforced concrete (RC) flat slabs. After importing slab geometries from BIM, the proposed procedure utilised internal forces output from Finite Element Model (FEM) to map required reinforcement in two stages. In the first stage, the reinforcement specifications matched the spatial resolution of the FEM. In the second, the reinforcement was adjusted by imposing constructability functions to limit the number of arrangements in terms of zones and bar spacing. The aim of the paper was to investigate the parametric capabilities of the proposed approach in the context of an optimisation model for the generation of material-efficient structural designs. Numerical examples were presented to demonstrate the efficiency of the automated specification procedure. The material efficiency and the design complexity of the developed reinforcement configurations were also assessed against a conventional solution under realistic design conditions

Investigating relationships between cost and CO₂ emissions in reinforced concrete structures using a BIM-based design optimisation approach

An integrated design approach for the cost and embodied carbon optimisation of reinforced concrete structures is presented in this paper to inform early design decisions. A BIM-based optimisation approach that utilises Finite Element Modelling (FEM) and a multi-objective genetic algorithm with constructability constraints is established for that purpose. A multilevel engineering analysis model is developed to perform structural layout optimisation, slab and columns sizing optimisation, and slab and columns reinforcement optimisation. The overall approach is validated using real buildings and the relationships between cost and carbon optimum solutions are explored. The study exhibits how cost effective and carbon efficient solutions could be obtained without compromising the feasibility of the optimised designs. Results demonstrate that the structural layout and the slab thickness are amongst the most important design optimisation parameters. Finally, the overall analysis suggests that the building form can influence the relationships between cost and carbon for the different structural components

BIM enabled optimisation framework for environmentally responsible and structurally efficient design systems

The present research investigates the potential for reducing the environmental impacts of structural systems through a more efficient use of materials. The main objective of this research is to explore and to develop a holistic and integrated methodology that utilises Building Information Modelling's (BIM) capabilities combined with structural analysis and Life Cycle Assessment (LCA) as well as a two-staged structural optimisation solver that achieves efficient and environmentally responsible steel design solutions. The implemented workflow utilises Autodesk Revit-BIM, Tally-LCA and Autodesk Robot-Structural Analysis. RobOpt is the plug-in that has been established using the Application Programming Interface (API) of Robot and the .NET framework of C?, and it inherits several structural functionalities based on Robot Finite Element Method (FEM) engine. The proposed RobOpt application can be accessed via a graphic user interface (GUI) within the Robot software. The developed BIM-enabled optimisation methodology could be utilised as a design tool to inform early stage structural design solutions. A prototypical steel framed structural system under certain loads has been explored. The resulting bespoke I-beam sections from the custom genetic algorithm (GA) optimisation demonstrate that significant savings-up to 21%-can be achieved in all tested environmental indicators when compared to the standard UK catalogue of steel sections. Considering all, the proposed framework constitutes a useful and an intuitive workflow, which aims to quantify the environmental savings of structural systems by utilising, advanced computational analysis and common construction techniques

Multilevel computational model for cost and carbon optimisation of reinforced concrete floor systems

The cost and carbon efficiency of building structures could be enhanced by the current developments in design automation and optimisation techniques. New ways to systematically assess design alternatives based on cost and carbon parameters are necessary. The study proposes a multilevel optimisation approach that combines Building Information Modelling (BIM) data and Finite Element Modelling (FEM) with a constrained genetic algorithm. The optimisation methodology is tested in a prototypical building floor system. Structural grid configurations, floor thicknesses and columns sizes and reinforcement details are identified. The results showed that the cost optimum design is 3% cheaper than the carbon optimum design but it has 7% more carbon. In addition, the concrete in the floor is the biggest contributor in both total cost and carbon. Relationships between cost- and carbon-optimum designs for the tested structural configuration are also discussed

Mesoscale modeling of combined aerosol and photo-oxidant processes in the Eastern Mediterranean

International audienceParticulate matter and photo-oxidant processes in the Eastern Mediterranean have been studied using the UAM-AERO mesoscale air quality model in conjunction with the NILU-CTM regional model. Meteorological data were obtained from the RAMS prognostic meteorological model. The modeling domain includes the eastern Mediterranean area between the Greek mainland and the island of Crete. The modeling system is applied to study the atmospheric processes in three periods, i.e. 13?16 July 2000, 26?30 July 2000 and 7?14 January 2001. The spatial and temporal distributions of both gaseous and particulate matter pollutants have been extensively studied together with the identification of major emission sources in the area. The modeling results were compared with field data obtained in the same period. The objective of the current modeling work was mainly to apply the UAM-AERO mesoscale model in the eastern Mediterranean in order to assess the performed field campaigns and determine that the applied mesoscale model is fit for this purpose. Comparison of the modeling results with measured data was performed for a number of gaseous and aerosol species. The UAM-AERO model underestimates the PM10 measured concentrations during summer and winter campaigns. Discrepancies between modeled and measured data are attributed to unresolved particulate matter emissions. Particulate matter in the area is mainly composed by sulphate, sea salt and crustal materials, and with significant amounts of nitrate, ammonium and organics. During winter the particulate matter and oxidant concentrations were lower than the summer values