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Power BI är ett verktyg för att hjälpa företag visualisera och analysera data. I Power BIanvänds Visuals för att bygga upp en lättförståelig datarepresentation, men alternativenär begränsade. För att få en mer skräddarsydd datavisualisering går det att utveckla egnaCustom Visuals, men informationen som finns tillgänglig är bristfällig. Målet med denhär uppsatsen är att göra ett bidrag med vägledning kring hur utveckling av CustomVisuals går till, samt undersöka vad det finns för möjligheter att skapa mer kreativalösningar för datarepresentation. För att testa vad som kan göras genom Custom Visuals skapades ett program med syfteatt på ett mer kreativt sätt visualisera den data som en av uppdragsgivarens kunderanvände sig av. Uppsatsen har utformats som delvis en genomgång av hur det härprogrammet har uppbyggts, men också som en handledning där utvecklare kan få hjälpmed de delar som krävs för att sätta upp miljön, samt ta del av vilka möjligheter detfinns genom språk, bildimplementation och datahantering, bland annat. / Power BI is a tool used by companies to help with analysing and visualizing their data.In Power BI you use Visuals to build more comprehensible data representation, howeverthe alternatives that the software provides are restricted. To make a more customizeddata visualization you have the option to create your own Cusom Visuals, although theavailable information is limited. The goal for this essay is to explore the opportunitiesfor creative data representation through Power BI and to make a contribution for whenothers seek to develop their own Custom Visuals. A program was created to examine the possibilites with Custom Visuals with the purpose to create a more innovative solution for data representation for one of the company’sclients. The results of the project are in two parts, a walktrough of the program that wascreated for the client, but also a tutorial for developers searching for more informationregarding how to create Custom Visuals. The tutorial describes how to set up the environment, available languages, how to implement pictures and how to manage data,among other things.

For larger instances of multi-objective optimisation problems, the exact Pareto frontier can be both difficult and time-consuming to calculate. There is a wide range of methods to find feasible solutions to such problems, but techniques for finding good optimistic bounds to compare the feasible solutions with are missing. In this study, we investigate the use of Lagrangian relaxation to create optimistic bounds to bi-objective optimisation problems with complicating side constraints. The aim is to develop an effective method to produce optimistic bounds that are closer to the Pareto frontier than the commonly used linear programming bounds.  In order to use Lagrangian relaxation on the bi-objective problem, the objectives are combined using the weighted sum method. A Lagrangian dual function is then constructed by relaxing the complicating constraints and the subgradient method is used to optimise the dual problem in order to find an optimistic solution. By solving the single-objective problem for multiple weights, an optimistic bound to the Pareto frontier can be constructed. The subgradient method also includes a heuristic to find feasible solutions. The feasible solutions found by the heuristic form a pessimistic bound to the frontier. The method has been implemented and tested on several instances of a capacitated facility location problem with cost and CO2 emission as objectives. The results indicate that, by using Lagrangian relaxation, an optimistic bound close to the Pareto frontier can be found in a relatively short time. The heuristic used also manages to produce good pessimistic bounds, and hence the Pareto frontier can be tightly enclosed. The optimistic bounds found by Lagrangian relaxation are better and more consistent along the Pareto frontier than the bounds found by linear programming.

No / Many datasets are available in the form of conventional databases, or simplified comma separated values. The machines do not adequately handle these types of unstructured data. There are compatibility issues as well, which are not addressed well to manage the transformation. The literature describes several rigid techniques that do the transformation from unstructured or conventional data sources to Resource Description Framework (RDF) with data loss and limited customization. These techniques do not present any remote way that helps to avoid compatibility issues among these data forms simultaneous utilization. In this article, a new approach has been introduced that allows data mapping. This mapping can be used to understand their differences at the level of data representations. The mapping is done using Extensible Markup Language (XML) based data structures as intermediate data presenter. This approach also allows bi-directional data transformation from conventional data format and RDF without data loss and with improved remote availability of data. This is a solution to the issue concerning update when dealing with any change in the remote environment for the data. Thus, traditional systems can easily be transformed into Semantic Web-based system. The same is true when transforming data back to conventional data format, i.e. Database (DB). This bidirectional transformation results in no data loss, which creates compatibility between both traditional and semantic form of data. It will allow applying inference and reasoning on conventional systems. The census un-employment dataset is used which is being collected from US different states. Remote bi-directional transformation is mapped on the dataset and developed linkage using relationships between data elements. This approach will help to handle both types of data formats to co-exist at the same time, which will create opportunities for data compatibility, statistical powers and inference on linked data found in remote areas.

Denna forskningsrapport undersöker hur företag kan dra nytta av en chattbot inom ett BusinessIntelligence (BI) system. Rapporten fokuserar på implementeringen av en chatbot med LargeLanguage Models (LLM) inom ett BI system och dess inverkan på användarupplevelsen ochverksamhetsutvecklingen. Genom en fallstudie och semistrukturerade intervjuer undersökerförfattarna användarnas uppfattning om chattboten. Resultaten visar att användarna överlag haren positiv inställning till implementationen av en chattbot och att användarupplevelsen ärmestadels positiv. Forskningen betonar även vikten av automatiserad validering och delning avkonfigurationer för att stärka användarnas förtroende för chattboten. Studien ger insikter kringhur chattboten kan utveckla verksamheten och hur chattboten påverkar användarupplevelsen. / This research report examines how companies can benefit from a chatbot within a BusinessIntelligence (BI) system. The report focuses on the implementation of a chatbot using LargeLanguage Models (LLM) within a BI system and its impact on user experience and businessdevelopment. Through a case study and semi-structured interviews, the authors investigate users'perceptions of the chatbot. The results indicate that users generally have a positive attitudetowards the implementation of a chatbot and that the user experience is mostly positive. Theresearch also emphasizes the importance of automated validation and sharing of configurationsto strengthen users' trust in the chatbot. The study provides insights into how the chatbot candevelop the business and how the chatbot affects user experience.

This dissertation presents three different aspects of the incorporation of directionality into the Monte Carlo ray-trace (MCRT) environment: (1) the development of a methodology for using directional surface optical data, (2) the measurement of the bi-directional reflectivity functions for two different surfaces, and (3) MCRT simulations performed using these directional data sets. The methodology presented is based upon a rigorous analytical formulation and is capable of performing simulations of radiation exchange involving directional emission, absorption and reflection given the bi-directional reflectivity functions (BDRF) of the participating surfaces. A wavelet compression technique is presented for the management of extremely large directional data sets. The BDRFs of two different surfaces were acquired using a Surface Optics Corporation model SOC-250 bi-directional reflectometer. These data were processed according to the methodology presented and an MCRT code was used to simulate the action of the SOC-250 in measuring radiant energy reflected from the surfaces of the two samples when illuminated by the source of the SOC-250. Another MCRT code was used to simulate the radiant energy reflected into a plane at the exit of an open-ended rectangular box when the entrance to the box is illuminated by source of the SOC-250. The RMS error between the MCRT simulations of sampling using the SOC-250 and the measured data were determined and then divided by the mean BDRF level of the measured data (RMS/mean[rho]) to provide an estimate of convergence. The RMS/mean[rho] was observed to fall from as much as 138 to 0.84 for the aluminum substrate coated with Krylon Shortcuts Hunter Green Satin aerosol paint as the number of energy bundles emitted in the MCRT simulation went from 103 to 106 at an incident zenith angle of 40 deg. The RMS/mean[rho] was observed to fall from as much as 2.2 to 0.2 for the Norton (150 Fine grit) all-purpose sandpaper coated with Krylon Shortcuts Hunter Green Satin aerosol paint as the number of energy bundles emitted in the MCRT simulation went from 103 to 106 at an incident zenith angle of 40 deg. / Ph. D.

The Army-sponsored Institute for Soldier Nanotechnologies (ISN) was an entrepreneurial research institute established at the Massachusetts Institute of Technology (MIT) in 2002. Using Science and Technology Studies (STS) concepts from Actor-Network Theory, I study the founding era of this twenty-first century laboratory-based community, from 2002-2007. Actor-Network concepts of enrollment and translation, described by Bruno Latour, and heterogeneous engineering, described by John Law, are used as I 'follow the actors' founding this emergent institution. The operationalization of translation is traced through four case studies, structured around Defense funding constructs and Science and Technology communities: 6.0 Founding the Institute; 6.1 Building Basic Research Networks; 6.2 Shaping Applied Research for Cancer Research and Science Education to include non-users; and 6.3 Student Prototyping Teams Accelerating ISN Research for Traumatic Brain Injuries (TBI). Scientists, engineers, and transitioners partnered in new ways to transition innovative technologies to improve human protection, with soldiers as the first of many users. Using public information, I used qualitative and quantitative methodologies to assess the actor networks and research portfolio changes. These historical case studies extend STS with operationalization of translation and a new dynamic of bi-directional actor enrollment, as research teams transitioned nanotechnologies and prototypes. / Doctor of Philosophy / The Institute for Soldier Nanotechnologies (ISN) was an Army-sponsored entrepreneurial research institute established at the Massachusetts Institute of Technology (MIT) in 2002. This historical study examines the founding era, rarely described for start-up organizations. Science and Technology Studies (STS) concepts of Actor-Network Theory enrollment and translation are traced through four case studies: Founding the Institute; Building Basic Research Networks; Shaping Applied Research for Cancer Research and Science Education to include non-users; and Student Prototyping Teams Accelerating Research for Traumatic Brain Injuries (TBI). The scientists, engineers, and transitioners partnered in new ways to transition technologies to improve human protection, with soldiers as the first of many users. Using public information, I provide qualitative and quantitative methodologies to assess the social networks of actors, as well as the composition and changes in the research portfolio. These case studies show what the ISN members did and how the small teams innovated, operationalizing translation through enrollment, and transitioning nanotechnologies and other prototypes.

The bi-directional dc/dc converter is a very popular and effective tool for alternative energy applications. One way it can be utilized is to charge and discharge batteries used in residential solar energy systems. In the day, excess power from the PV panels is used to charge the batteries. During the night, the charged batteries will power the dc bus for loads in the house such as home appliances. The dual active bridge (DAB) converter is very useful because of its high power capability and efficiency. Its symmetry is effective in transferring power in both directions. However, the DAB converter has drawbacks in the start-up stage. These drawbacks in boost mode include high in-rush current during start-up, and the fact that the high side voltage cannot be lower than the low side voltage. A popular existing method to alleviate this problem is the use of an active clamp and a flyback transformer in the circuit topology to charge the high side before the converter is switched into normal boost operation. The active clamp not only helps eliminate the transient spike caused by the transformer leakage, but also continues to be used during steady state. However, this method introduces a new current spike occurring when the converter transitions from start-up mode to boost mode. To alleviate this new setback, an additional transitional stage is proposed to significantly reduce the current spike without the use of any additional components. The converter is current-fed on the low side, and voltage-fed on the high side. A simple phase shift control is used in buck mode and PWM control is used during the boost mode for both the start-up mode and the normal boost operation. This thesis discusses the performance results of a 48-400 V dc/dc converter with 1000 W power output. / Master of Science

Due to the concerns regarding increasing fuel cost and air pollution, plug-in electric vehicles (PEVs) are drawing more and more attention. PEVs have a rechargeable battery that can be restored to full charge by plugging to an external electrical source. However, the commercialization of the PEV is impeded by the demands of a lightweight, compact, yet efficient on-board charger system. Since the state-of-the-art Level 2 on-board charger products are largely silicon (Si)-based, they operate at less than 100 kHz switching frequency, resulting in a low power density at 3-12 W/in3, as well as an efficiency no more than 92 - 94% Advanced power semiconductor devices have consistently proven to be a major force in pushing the progressive development of power conversion technology. The emerging wide bandgap (WBG) material based power semiconductor devices are considered as game changing devices which can exceed the limit of Si and be used to pursue groundbreaking high frequency, high efficiency, and high power density power conversion. Using wide bandgap devices, a novel two-stage on-board charger system architecture is proposed at first. The first stage, employing an interleaved bridgeless totem-pole AC/DC in critical conduction mode (CRM) to realize zero voltage switching (ZVS), is operated at over 300 kHz. A bi-directional CLLC resonant converter operating at 500 kHz is chosen for the second stage. Instead of using the conventional fixed 400 V DC-link voltage, a variable DC-link voltage concept is proposed to improve the efficiency within the entire battery voltage range. 1.2 kV SiC devices are adopted for the AC/DC stage and the primary side of DC/DC stage while 650 V GaN devices are used for the secondary side of the DC/DC stage. In addition, a two-stage combined control strategy is adopted to eliminate the double line frequency ripple generated by the AC/DC stage. The much higher operating frequency of wide bandgap devices also provides us the opportunity to use PCB winding based magnetics due to the reduced voltage-second. Compared with conventional litz-wire based transformer. The manufacture process is greatly simplified and the parasitic is much easier to control. In addition, the resonant inductors are integrated into the PCB transformer so that the total number of magnetic components is reduced. A transformer loss model based on finite element analysis is built and used to optimize the transformer loss and volume to get the best performance under high frequency operation. Due to the larger inter-winding capacitor of PCB winding transformer, common mode noise becomes a severe issue. A symmetrical resonant converter structure as well as a symmetrical transformer structure is proposed. By utilizing the two transformer cells, the common mode current is cancelled within the transformers and the total system common mode noise can be suppressed. In order to charge the battery faster, the single-phase on-board charger concept is extended to a higher power level. By using the three-phase interleaved CLLC resonant converter, the charging power is pushed to 12.5 kW. In addition, the integrated PCB winding transformer in single phase is also extended to the three phase. Due to the interleaving between each phase, further integration is achieved and the transformer size is further reduced. / PHD / Plug-in electric vehicles (PEVs) are drawing more and more attention due to the advantages of energy saving, low CO₂ emission and cost effective in the long run. The power source of PEVs is a high voltage DC rechargeable battery that can be restored to full charge by plugging to an external electrical source, during which the battery charger plays an essential role by converting the grid AC voltage to the required battery DC voltage. Silicon based power semiconductor devices have been dominating the market over the past several decades and achieved numerous outstanding performances. As they almost reach their theatrical limit, the progress to purse the high-efficiency, high-density and high-reliability power conversion also slows down. On this avenue, the emerging wide bandgap (WBG) material based power semiconductor devices are envisioned as the game changer: they can help increase the switching frequency by a factor of ten compared with their silicon counterparts while keeping the same efficiency, resulting in a small size, lightweight yet high efficiency power converter. With WBG devices, magnetics benefit the most from the high switching frequency. Higher switching speed means less energy to store during one switching cycle. Consequently, the size of the magnetic component can be greatly reduced. In addition, the reduced number of turns provides the opportunity to adopt print circuit board as windings. Compared with the conventional litz-wire based magnetics, planar magnetics not only can effectively reduce the converter size, but also offer improved reliability through automated manufacturing process with repeatable parasitics. This dissertation is dedicated to address the key high-frequency oriented challenges of adopting WBG devices (including both SiC and GaN) and integrated PCB winding magnetics in the battery charger applications. First, a novel two-stage on-board charger system architecture is proposed. The first stage employs an interleaved bridgeless totem-pole AC/DC with zero voltage switching, and a bi-directional CLLC resonant converter is chosen for the second stage. Second, a PCB winding based transformer with integrated resonant inductors is designed, so that the total number of magnetic components is reduced and the manufacturability is greatly improved. A transformer loss model based on finite element analysis is built and employed to optimize the transformer loss and volume to get the best performance under high frequency operations. In addition, a symmetrical resonant converter structure as well as a symmetrical transformer structure is proposed to solve the common noise issue brought by the large parasitic capacitance in PCB winding magnetics. By utilizing the two transformer cells, the common mode current is cancelled within the transformers, and the total system common mode noise can be suppressed. Finally, the single-phase on-board charger concept is extended to a higher power level to charge the battery faster. By utilizing the three-phase interleaved CLLC resonant converter as DC/DC stage, the charging power is pushed to 12.5 kW. In addition, the integrated PCB winding magnetic in single phase is also extended to the three phase. Due to the interleaving between the three phase, further integration is achieved and the transformer size is further reduced.