A Meta-Review of Indoor Positioning Systems

An accurate and reliable Indoor Positioning System (IPS) applicable to most indoor scenarios has been sought for many years. The number of technologies, techniques, and approaches in general used in IPS proposals is remarkable. Such diversity, coupled with the lack of strict and verifiable evaluations, leads to difficulties for appreciating the true value of most proposals. This paper provides a meta-review that performed a comprehensive compilation of 62 survey papers in the area of indoor positioning. The paper provides the reader with an introduction to IPS and the different technologies, techniques, and some methods commonly employed. The introduction is supported by consensus found in the selected surveys and referenced using them. Thus, the meta-review allows the reader to inspect the IPS current state at a glance and serve as a guide for the reader to easily find further details on each technology used in IPS. The analyses of the meta-review contributed with insights on the abundance and academic significance of published IPS proposals using the criterion of the number of citations. Moreover, 75 works are identified as relevant works in the research topic from a selection of about 4000 works cited in the analyzed surveys

New Cluster Selection and Fine-grained Search for k-Means Clustering and Wi-Fi Fingerprinting

Ponencia presentada en 2020 International Conference on Localization and GNSS (ICL-GNSS), 02-04 June 2020, Tampere, FinlandWi-Fi fingerprinting is a popular technique for Indoor Positioning Systems (IPSs) thanks to its low complexity and the ubiquity of WLAN infrastructures. However, this technique may present scalability issues when the reference dataset (radio map) is very large. To reduce the computational costs, k-Means Clustering has been successfully applied in the past. However, it is a general-purpose algorithm for unsupervised classification. This paper introduces three variants that apply heuristics based on radio propagation knowledge in the coarse and fine-grained searches. Due to the heterogeneity either in the IPS side (including radio map generation) and in the network infrastructure, we used an evaluation framework composed of 16 datasets. In terms of general positioning accuracy and computational costs, the best proposed k-means variant provided better general positioning accuracy and a significantly better computational cost –around 40% lower– than the original k-means

Providing Databases for Different Indoor Positioning Technologies: Pros and Cons of Magnetic Field and Wi-Fi Based Positioning

Localization is one of the main pillars for indoor services. However, it is still very difficult for the mobile sensing community to compare state-of-the-art indoor positioning systems due to the scarcity of publicly available databases. To make fair and meaningful comparisons between indoor positioning systems, they must be evaluated in the same situation, or in the same sets of situations. In this paper, two databases are introduced for studying the performance of magnetic field and Wi-Fi fingerprinting based positioning systems in the same environment (i.e., indoor area). The “magnetic” database contains more than 40,000 discrete captures (270 continuous samples), whereas the “Wi-Fi” one contains 1,140 ones. The environment and both databases are fully detailed in this paper. A set of experiments is also presented where two simple but effective baselines have been developed to test the suitability of the databases. Finally, the pros and cons of both types of positioning techniques are discussed in detail.The authors gratefully acknowledge funding from the European Union through the GEO-C project (H2020-MSCA-ITN- 2014, Grant Agreement no. 642332, http://www.geo-c.eu/). The authors also gratefully acknowledge funding from the Spanish Ministry of Economy and Competitiveness through the “Metodolog´ıas avanzadas para el diseno, desarrollo, eval- ˜ uacion e integraci ´ on de algoritmos de localizaci ´ on en inte- ´ riores” project (Proyectos I+D Excelencia, codigo TIN2015- ´ 70202-P) and the “Red de Posicionamiento y Navegacion en ´ Interiores” network (Redes de Excelencia, codigo TEC2015- ´ 71426-REDT). The authors would like to thank all the current and past members of the Geospatial Technologies Research Group and Ubik Geospatial Solutions S.L. for their valuable help in creating the SmartUJI platform and providing us with the supporting services that allowed integrating the existing GIS services in the applications developed to create both databases

Situation Goodness Method for Weighted Centroid-Based Wi-Fi APs Localization

Knowing the location of Wi-Fi antennas may be critical for indoor localization. However, in a real environment, their positions may be unknown since they can be managed by external entities. This paper introduces a new method for evaluating the suitability of using the weighted centroid method for the 2D localization of a Wi-Fi AP. The method is based on the idea that the weighted centroid method provides its best results when there are fingerprints taken around the AP. In order to find the probability of being in the presence of such situations, a natural neighbor interpolation method is used to find the regions with the highest signal strengths. A geometrical method is then used to characterize that probability based on the distribution of those regions in relation to the AP position estimation given by the weighted centroid method. The paper describes the testing location and the used Wi-Fi fingerprints database. That database is used to create new databases that recreate different sampling possibilities through a samples deletion strategy. The original database and the newly created ones are then used to evaluate the localization results of several AP localization methods and the new method proposed in this paper. The evaluation results have shown that the proposed method is able to provide a proper probability for the suitability of using the weighted centroid method for localizing a Wi-Fi AP

Discovering location based services: A unified approach for heterogeneous indoor localization systems

The technological solutions and communication capabilities offered by the Internet of Things paradigm, in terms of raising availability of wearable devices, the ubiquitous internet connection, and the presence on the market of service-oriented solutions, have allowed a wide proposal of Location Based Services (LBS). In a close future, we foresee that companies and service providers will have developed reliable solutions to address indoor positioning, as basis for useful location based services. These solutions will be different from each other and they will adopt different hardware and processing techniques. This paper describes the proposal of a unified approach for Indoor Localization Systems that enables the cooperation between heterogeneous solutions and their functional modules. To this end, we designed an integrated architecture that, abstracting its main components, allows a seamless interaction among them. Finally, we present a working prototype of such architecture, which is based on the popular Telegram application for Android, as an integration demonstrator. The integration of the three main phases –namely the discovery phase, the User Agent self-configuration, and the indoor map retrieval/rendering– demonstrates the feasibility of the proposed integrated architectur

EFEITO DE ENZIMAS FIBROLÍTICAS SOBRE A DEGRADAÇÃO MICROBIANA RUMINAL DA FIBRA DE CANA-DE-AÇÚCAR

Com o objetivo de estudar os limitantes da degradação da fibra da cana-de-açúcar para utilizá-la como alimento para bovinos, fracionaram-se os componentes fibrosos da cana-de-açúcar (variedade Mex69-290) em fibra em detergente neutro (FDN) e em fibra em detergente ácido (FDA). A cana integral e as fibras foram incubadas com bactérias ruminais, na presença ou ausência de enzimas fibrolíticas (Fibrozyme, Alltech Inc.). Determinaram-se o crescimento microbiano e as bactérias totais, assim como a taxa de crescimento, a taxa de geração, o tempo de colonização e a degradabilidade. Os resultados foram analisados em um delinea­mento de blocos ao acaso, com arranjo fatorial 2 x 3, com duas doses de enzima e três substratos, utilizando quatro repetições de incubação. Observou-se o maior crescimento microbiano para cana integral e os menores para suas fibras. A degradabilidade in vitro foi de 0,701, 0,392 e 0,191, respectivamente para cana integral, FDN e FDA (P<0,01). A fração FDA com a adição das enzimas fibrolíticas teve sua degradabilidade aumentada de 0,387 para 0,425 (P<0,01). O crescimento microbiano foi limitado nas frações fibrosas, possivelmente pelo grau de lignificação das paredes celulares. A maior degradabilidade in vitro das frações fibrosas está associada à presença de açúcares solúveis. A adição de enzimas fibrolíticas aumentou o crescimento microbiano máximo e a digestibilidade da FDA, indicando que estas podem ser um potencial aditivo para melhorar o aproveitamento de dietas com cana-de-açúcar. PALAVRAS-CHAVES: Crescimento microbiano, degradabilidade in vitro, parede celular

Fórmulas à base de ervas na alimentação de cordeiros para melhorar o comportamento produtivo

El objetivo de esta revisión de publicaciones científicas es identificar los aditivos poliherbales comerciales disponibles para finalización de corderos y evaluar los cambios productivos al utilizarlos. Se realizó una búsqueda sistematizada de artículos científicos en los buscadores PubMed, Web of Science y Science Direct utilizando las palabras clave lamb, growth performance, polyherbals y feed plant additives. Para incluir los artículos pasaron por un proceso de selección buscando que evaluaran corderos en finalización, incluyeran en las raciones formulas poliherbales comerciales, estuvieran publicados en revistas indizadas en JCR, Web of Science y Scimago Journal Rank y estuvieran escritas en idioma inglés. Se encontró reporte de 6 mezclas poliherbales con marca registrada las cuales, promediaron un incremento en la ganancia diaria de peso de 10.86 % cuando son incluidas en las raciones. &nbsp;The objective of this review of scientific publications is to identify the commercial polyherbal additives available for finishing lambs and to evaluate the productive changes when using them. A systematic search of scientific articles was carried out in the PubMed, Web of Science and Science Direct search engines using the keywords lamb, growth performance, polyherbals and feed plant additives. To include the articles, they went through a selection process seeking to evaluate finishing lambs, include commercial polyherbal formulas in the rations, be published in journals indexed in JCR, Web of Science and Scimago Journal Rank and were written in English. A report of 6 trademarked polyherbal mixtures was found, which averaged an increase in daily weight gain of 10.86% when they are included in the rations.O objetivo desta revisão de publicações científicas é identificar os aditivos fitoterápicos comerciais disponíveis para terminação de cordeiros e avaliar as alterações produtivas ao utilizá-los. Uma busca sistemática de artigos científicos foi realizada nos motores de busca PubMed, Web of Science e Science Direct usando as palavras-chave cordeiro, desempenho de crescimento, poliervas e aditivos de plantas para ração. Para incluir os artigos, eles passaram por um processo de seleção buscando que eles avaliassem cordeiros em terminação, incluíssem fórmulas polierógenas comerciais nas rações, fossem publicados em periódicos indexados no JCR, Web of Science e Scimago Journal Rank e fossem escritos em inglês. Foi encontrado um relato de 6 misturas de poliervas de marca registrada, que tiveram um aumento médio no ganho de peso diário de 10,86% quando incluídas nas rações

Off-line evaluation of mobile-centric indoor positioning systems: the experiences from the 2017 IPIN competition

The development of indoor positioning solutions using smartphones is a growing activity with an enormous potential for everyday life and professional applications. The research activities on this topic concentrate on the development of new positioning solutions that are tested in specific environments under their own evaluation metrics. To explore the real positioning quality of smartphone-based solutions and their capabilities for seamlessly adapting to different scenarios, it is needed to find fair evaluation frameworks. The design of competitions using extensive pre-recorded datasets is a valid way to generate open data for comparing the different solutions created by research teams. In this paper, we discuss the details of the 2017 IPIN indoor localization competition, the different datasets created, the teams participating in the event, and the results they obtained. We compare these results with other competition-based approaches (Microsoft and Perf-loc) and on-line evaluation web sites. The lessons learned by organising these competitions and the benefits for the community are addressed along the paper. Our analysis paves the way for future developments on the standardization of evaluations and for creating a widely-adopted benchmark strategy for researchers and companies in the field.We would like to thank Topcon Corporation for sponsoring the competition track with an award for the winning team. We are also grateful to Francesco Potorti, Sangjoon Park, Hideo Makino, Nobuo Kawaguchi, Takeshi Kurata and Jesus Urena for their invaluable help in organizing and promoting the IPIN competition and conference. Many thanks to Raul Montoliu, Emilio Sansano, Marina Granel and Luis Alisandra for collecting the databases in the UJITI building. Parts of this work were carried out with the financial support received from projects and grants: REPNIN network (TEC2015-71426-REDT), LORIS (TIN2012-38080-C04-04), TARSIUS (TIN2015-71564-C4-2-R (MINECO/FEDER)), SmartLoc (CSIC-PIE Ref. 201450E011), "Metodologias avanzadas para el diseno, desarrollo, evaluacion e integracion de algoritmos de localizacion en interiores" (TIN2015-70202-P), GEO-C (Project ID: 642332, H2020-MSCA-ITN-2014-Marie Sklodowska-Curie Action: Innovative Training Networks), and financial support from the Ministry of Science and Technology, Taiwan (106-3114-E-007-005 and 105-2221-E-155-013-MY3). The HFTS team has been supported in the frame of the German Federal Ministry of Education and Research programme "FHprofUnt2013" under contract 03FH035PB3 (Project SPIRIT). The UMinho team has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT-Fundacao para a Ciencia e Tecnologia within the Project Scope: UID/CEC/00319/2013. G.M. Mendoza-Silva gratefully acknowledges funding from grant PREDOC/2016/55 by Universitat Jaume I.info:eu-repo/semantics/publishedVersio

The smartphone-based offline indoor location competition at IPIN 2016: analysis and future work

This paper presents the analysis and discussion of the off-site localization competition track, which took place during the Seventh International Conference on Indoor Positioning and Indoor Navigation (IPIN 2016). Five international teams proposed different strategies for smartphone-based indoor positioning using the same reference data. The competitors were provided with several smartphone-collected signal datasets, some of which were used for training (known trajectories), and others for evaluating (unknown trajectories). The competition permits a coherent evaluation method of the competitors' estimations, where inside information to fine-tune their systems is not offered, and thus provides, in our opinion, a good starting point to introduce a fair comparison between the smartphone-based systems found in the literature. The methodology, experience, feedback from competitors and future working lines are described.We would like to thank Tecnalia Research & Innovation Foundation for sponsoring the competition track with an award for the winning team. We are also grateful to Francesco Potortì, Sangjoon Park, Jesús Ureña and Kyle O’Keefe for their invaluable help in promoting the IPIN competition and conference. Parts of this work was carried out with the financial support received from projects and grants: LORIS (TIN2012-38080-C04-04), TARSIUS (TIN2015-71564-C4-2-R (MINECO/FEDER)), SmartLoc (CSIC-PIE Ref.201450E011), “Metodologías avanzadas para el diseño, desarrollo, evaluación e integración de algoritmos de localización en interiores” (TIN2015-70202-P), REPNIN network (TEC2015-71426-REDT) and the José Castillejo mobility grant (CAS16/00072). The HFTS team has been supported in the frame of the German Federal Ministry of Education and Research programme “FHprofUnt2013” under contract 03FH035PB3 (Project SPIRIT). The UMinho team has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT — Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013.info:eu-repo/semantics/publishedVersio

Evaluating Indoor Positioning Systems in a Shopping Mall: The Lessons Learned From the IPIN 2018 Competition

The Indoor Positioning and Indoor Navigation (IPIN) conference holds an annual competition in which indoor localization systems from different research groups worldwide are evaluated empirically. The objective of this competition is to establish a systematic evaluation methodology with rigorous metrics both for real-time (on-site) and post-processing (off-site) situations, in a realistic environment unfamiliar to the prototype developers. For the IPIN 2018 conference, this competition was held on September 22nd, 2018, in Atlantis, a large shopping mall in Nantes (France). Four competition tracks (two on-site and two off-site) were designed. They consisted of several 1 km routes traversing several floors of the mall. Along these paths, 180 points were topographically surveyed with a 10 cm accuracy, to serve as ground truth landmarks, combining theodolite measurements, differential global navigation satellite system (GNSS) and 3D scanner systems. 34 teams effectively competed. The accuracy score corresponds to the third quartile (75 th percentile) of an error metric that combines the horizontal positioning error and the floor detection. The best results for the on-site tracks showed an accuracy score of 11.70 m (Track 1) and 5.50 m (Track 2), while the best results for the off-site tracks showed an accuracy score of 0.90 m (Track 3) and 1.30 m (Track 4). These results showed that it is possible to obtain high accuracy indoor positioning solutions in large, realistic environments using wearable light-weight sensors without deploying any beacon. This paper describes the organization work of the tracks, analyzes the methodology used to quantify the results, reviews the lessons learned from the competition and discusses its future