Online sales and business model innovation in art markets: a case study

Every year online sales represent a higher percentage of the sales total in nearly all sectors of the economy, and the art markets are no exception. However, there are few empirical studies showing how online sales and digital technologies are transforming the art markets at a micro-level. This study is based on the detailed examination of the financial performance of one of the two largest Portuguese auction houses, Cabral Moncada Leilões (CML), over a period of twelve years (2007-2018), complemented with interviews with its top-managers. It analyses a set of financial indicators (e.g., EBIT, ROA, EQUITY, sales volume, net results, etc.), along with some markers that are specific to the auction sector (e.g., average lot value, number of auctions per year, etc.). From this analysis it is possible to conclude that the deterioration of this company's financial performance was the driving force that led it to explore the potential of digital economy. In the process, its business model changed dramatically, leading the company to a different market position and to the enlargement of its national and international customer base.info:eu-repo/semantics/publishedVersio

The Phoenix Deep Survey: The 1.4 GHz microJansky catalogue

The initial Phoenix Deep Survey (PDS) observations with the Australia Telescope Compact Array have been supplemented by additional 1.4 GHz observations over the past few years. Here we present details of the construction of a new mosaic image covering an area of 4.56 square degrees, an investigation of the reliability of the source measurements, and the 1.4 GHz source counts for the compiled radio catalogue. The mosaic achieves a 1-sigma rms noise of 12 microJy at its most sensitive, and a homogeneous radio-selected catalogue of over 2000 sources reaching flux densities as faint as 60 microJy has been compiled. The source parameter measurements are found to be consistent with the expected uncertainties from the image noise levels and the Gaussian source fitting procedure. A radio-selected sample avoids the complications of obscuration associated with optically-selected samples, and by utilising complementary PDS observations including multicolour optical, near-infrared and spectroscopic data, this radio catalogue will be used in a detailed investigation of the evolution in star-formation spanning the redshift range 0 < z < 1. The homogeneity of the catalogue ensures a consistent picture of galaxy evolution can be developed over the full cosmologically significant redshift range of interest. The 1.4 GHz mosaic image and the source catalogue are available on the web at http://www.atnf.csiro.au/~ahopkins/phoenix/ or from the authors by request.Comment: 16 pages, 11 figures, 4 tables. Accepted for publication by A

Development and test of an intra-vehicular network based on bluetooth low energy

This paper presents the development and test of an intra-vehicular system, based on Bluetooth Low Energy (BLE), designed to present to the driver, in real-time, information collected from multiple sensors distributed inside of the car, using an Android smartphone. The architecture of the implemented BLE network is composed by the smartphone, which has the role of central station, and two BLE modules (peripheral stations) based on the CC2540 system-on-chip, which collect relevant sensor information from the battery system and the traction system of an electric car. Results based on an experimental performance evaluation of the wireless network show that the network is able to satisfy the application requirements, as long as the network parameters are properly configured taking into account the peculiarities of the BLE data transfer modes and the limitations of the BLE platform.This work is supported by FCT with the reference project UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI-01-0145-FEDER-006941.info:eu-repo/semantics/publishedVersio

Bidirectional power converters for EV battery chargers

[Excerpt] The introduction of electric mobility into the transport sector has significantly contributed to the mitigation of environmental issues [...]This work has been supported by FCT—Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020. This work has been supported by the MEGASOLAR Project POCI-01-0247-FEDER-047220

Internet of things systems and applications for smart buildings

[Excerpt] Recent research advances in sensors, wireless communications, network protocols, microelectronics, cloud computing, and machine learning, among others, are driving the growth of the Internet of Things (IoT). The proliferation of IoT systems is increasingly pervasive, covering application areas such as smart grids, industrial automation, healthcare, sports/fitness, smart farming, environmental monitoring, smart cities, intelligent transportation systems, logistics, etc. One of the main driving areas of the IoT is in the context of smart buildings and smart homes, where several applications are envisioned, such as: energy consumption reduction; energy management of smart grids, battery storage systems, electric mobility, and renewable energy sources; monitoring and control of indoor environment parameters, such air quality and thermal comfort; and structural health monitoring. In this sense, the IoT system generally comprises, among other components, a network of IoT devices interfacing with sensors and actuators that are remotely configured, monitored and controlled, manually by the users and/or through intelligent automatic algorithms, with the support of cloud computing services. In this editorial, we provide a brief review of the application of the IoT paradigm in different research areas, with the focus on smart home and smart building scenarios. [...

A low-cost ZigBee-based wireless industrial automation system

This paper describes the development of an industrial automation system based on a ZigBee wireless sensor network, designed for the monitoring and control of multiple refrigeration equipments in an industrial area, replacing the existing cabled network, which is based on the LonWorks platform. For this purpose, ZigBee routers were used to replace the local controllers at the refrigeration equipments, while the central management controller was re-placed by a ZigBee coordinator and a PC. The proposed system was devel-oped using a hardware platform based in the CC2530 integrated circuit and the Z-Stack software. Results from experimental field tests performed in an industrial environment are provided in order to assess the performance of the developed ZigBee network.This work is supported by FCT (Fundação para a Ciência e Tecnologia) with the reference project UID/EEA/04436/2013, and by FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI-01-0145-FEDER-006941

Sistema distribuído de monitorização de consumos e de qualidade de energia elétrica

Este artigo descreve a implementação e teste de um sistema distribuído de medição de grandezas elétricas, concebido para utilização com cargas tipicamente existentes nas residências, que possibilita a monitorização remota do consumo e também possui capacidade de deteção de eventos de qualidade de energia elétrica. O sistema é operado pelo utilizador a partir de um computador, através de um programa monitorizador dotado de interface gráfica, que recebe os dados recolhidos por um conjunto de nós sensores ligados às cargas que se deseja monitorizar. A comunicação de dados assenta sobre uma rede de sensores sem fios desenvolvida com base nos protocolos IEEE 802.15.4 e ZigBee. Os nós da rede são baseados no circuito integrado CC2530, da Texas Instruments, que integra um microcontrolador e um transceiver RF num mesmo chip. A implementação do sistema envolveu a concepção e desenvolvimento do hardware dos nós sensores, que efetuam a medição das grandezas elétricas, do software embebido nos nós da rede de sensores sem fios, que gere a aquisição e envio dos dados dos nós sensores até ao computador, e do software monitorizador no computador. Os resultados obtidos nos testes realizados excederam as expetativas iniciais, tendo os erros de medição ficado abaixo do patamar de 1%.Fundação para a Ciência e a Tecnologia (FCT

The Phoenix Deep Survey: spectroscopic catalog

The Phoenix Deep Survey is a multi-wavelength survey based on deep 1.4 GHz radio imaging, reaching well into the sub-100 microJy level. One of the aims of this survey is to characterize the sub-mJy radio population, exploring its nature and evolution. In this paper we present the catalog and results of the spectroscopic observations aimed at characterizing the optically ``bright'' (R<~ 21.5 mag) counterparts of faint radio sources. Out of 371 sources with redshift determination, 21% have absorption lines only, 11% show AGN signatures, 32% are star-forming galaxies, 34% show narrow emission lines that do not allow detailed spectral classification (due to poor signal-to-noise ratio and/or lack of diagnostic emission lines) and the remaining 2% are identified with stars. For the star-forming galaxies with a Balmer decrement measurement we find a median extinction of A(Ha)=1.9 mag, higher than that of optically selected samples. This is a result of the radio selection, which is not biased against dusty systems. Using the available spectroscopic information, we estimate the radio luminosity function of star-forming galaxies in two independent redshift bins at z~0.1 and 0.3 respectively. We find direct evidence for strong luminosity evolution of these systems consistent with L(1.4 GHz) ~ (1+z)^(2.7).Comment: 39 pages, 12 figures. References added, and minor changes to reflect published versio