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 (75th 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

Usefulness as key parameter in assessing accessibility and usability in architecture. A theorem for explaining a twin concept in the building code

In national building codes, like the Danish and the Swedish ones, accessibility and usability are subjected to an open interpretation on a comprehensive level, supplemented by specified requirements on a detailed level. The aim of the pre­sent study is to position the twin concept with regard to its everyday understanding, and thereby suggest a definition. The study has been executed as a case study among a cohort of 370 experienced Danish professionals. The research material was assembled by use of mini-questionnaires. Conclusions derived from this material were synthesized with the respondents’ suggestions of exemplary models, which allegedly displayed an appropriate level of accessible and usable architecture and built environment. Based on the every­day understanding of the twin concept and paired with analyses of some exemplary models, this study suggests that accessibility and usability with respect to the user can be seen as constituents of buildings’ overall performative capacity. This capacity can be defined as usefulness, the potential sum of various adjustments of an accessible and usable nature. Ultimately, usefulness refers to the individual user’s level of independent usages of the particular architectural space.

On the trade-off between electrical power consumption and flight performance in fixed-wing UAV autopilots

This paper sets out a study of the autopilot design for fixed wing Unmanned Aerial Vehicles (UAVs) taking into account the aircraft stability, as well as the power consumption as a function of the selected control strategy. To provide some generality to the outcomes of this study, construction of a reference small-UAV model, based on averaging the main aircraft defining parameters, is proposed. Using such a reference model of small, fixed-wing UAVs, different control strategies are assessed, especially with a view towards enlarging the controllers' sampling time. A beneficial consequence of this sample time enlargement is that the clock rate of the UAV autopilots may be proportionally reduced. This reduction in turn leads directly to decreased electrical power consumption. Such energy saving becomes proportionally relevant as the size and power of the UAV decrease, with benefits of lengthening battery life and, therefore, the flight endurance. Additionally, through the averaged model, which is derived from both published data and computations made from actual data captured from real UAVs, it is shown that behavior predictions beyond that of any particular UAV model may be extrapolated.Peer ReviewedPostprint (author's final draft

Analysis of WIMAX/BWA Licensing in India: A real option approach

Indian Internet and broadband market has experienced very slow growth and limited penetration till now. The introduction of Broadband Wireless Access (BWA) is expected to aid in increasing the penetration of internet and broadband in India. The report sheds light on the guidelines and procedure used in 4G/BWA spectrum auction and presents comparative analysis of the competing technologies, providing the information about suitability of each technology available. Recently held 4G/ BWA spectrum auction saw enthusiastic participation by the industry and even saw some new entrants in Indian broadband market. Government benefited by Rs, 385bn that it earned as revenue from the auction of the spectrum and projected it as successful auction. However, the question remains if the auctions were efficient and whether they led to creation of value or will it prove to be burden to the telecom operators and will depress their balance sheet for years to come. The report uses both traditional valuation methods such as Discounted Cash Flow as well as Real Option approach to answer such questions. Using DCF analysis, the broadband subscribers have been forecasted to grow from present 13.77mn to 544mn by the end of 2025. The wireless subscribers are forecasted to be 70% of the total broadband subscribers after 5 years of roll out as it will be difficult to replace all wireline subscribers with wireless subscribers in India due to the high cost of wireless broadband and new technology. WiMAX is expected to increase its presence with time and reach 90mn subscribers from meager 0.35mn subscribers by 2025. Using industry wide cost of capital as 12.05%, the Net Present Value has been found Rs 221bn aggregate with an IRR of 17.1%. Using Real option approach, the value of license has been calculated as Rs 437bn which is 13.5% more than the spectrum fees paid by the operators. This mismatch, between the auction value and the correct value that should have been discovered by supply-demand dynamics, can be due to limited participants in BWA spectrum auctions and companies such as TATA and Reliance opting out of the auction process midway as well as uncertainty about acceptance of new technology with Indian subscribers.WiMAX, broadband, 3G spectrum, 4G,broadband wireless access, valuation, licensing, real option

Remote monitoring and failure prediction of guiding elements and diverting pulleys in passenger elevators

Accelerated urbanization has lead to the rising height of buildings and demand for intensive high performance of elevators in recent years. Consequently, condition monitoring has become a highly desirable capability as the complexity of elevator systems increased. The goal of this study is to develop a monitoring method for elevator components which are subjected to mechanical degradation and failures. The method is capable of indicating the current health condition, predicting future failure as well as detecting emerging issues during operation. Studies of the fundamental principle of elements of condition monitoring such as measurement and measuring equipment, remaining useful life models laid the foundation for new method developing. Moreover, there were reviews of the implementation of health management systems in aerospace and marine industry. A prototype was built from the inductive sensor and open sources embedded system. The device has been installed in two different elevators for data acquisition. Basic data visualization and analysis models were employed for current health state assessment and failure trend prediction. The results include validation of the condition monitoring method and prediction of time-to-failure. Arithmetic means of displacement data determined operating condition whereas the linear regression model was used to predict failure event. Moreover, while suggesting the potential usefulness of the method for system condition assessment, the analysis of the data also exposed challenges inconsistency of the measuring method, data filtering technique as well as large data size requirement

High Intensity Laser Power Beaming for Wireless Power Transmission

This paper describes work supporting the development of a high intensity laser power beaming (HILPB) system for the purpose of wireless power transmission. The main contribution of this research is utilizing high intensity lasers to illuminate vertical multi-junction (VMJ) solar cells developed by NASA-GRC. Several HILPB receivers are designed, constructed and evaluated with various lasers to assess the performance of the VMJ cells and the receiver under a variety of conditions. Several matters such as parallel cell back-feeding, optimal receiver geometry, laser wavelength, non-uniform illumination and thermal effects at high intensities are investigated. Substantial power densities are achieved, and suggestions are made to improve the performance of the system in future iterations. Thus far, the highest amount of energy obtained from a receiver during these tests was 23.7778 watts. In addition, one VMJ cell was able to achieve a power density of 13.6 watts per cm2, at a conversion efficiency of 24 . These experiments confirm that the VMJ technology can withstand and utilize the high intensity laser energy without damage and/or significant reduction in the conversion efficienc

High Intensity Laser Power Beaming for Wireless Power Transmission

This paper describes work supporting the development of a high intensity laser power beaming (HILPB) system for the purpose of wireless power transmission. The main contribution of this research is utilizing high intensity lasers to illuminate vertical multi-junction (VMJ) solar cells developed by NASA-GRC. Several HILPB receivers are designed, constructed and evaluated with various lasers to assess the performance of the VMJ cells and the receiver under a variety of conditions. Several matters such as parallel cell back-feeding, optimal receiver geometry, laser wavelength, non-uniform illumination and thermal effects at high intensities are investigated. Substantial power densities are achieved, and suggestions are made to improve the performance of the system in future iterations. Thus far, the highest amount of energy obtained from a receiver during these tests was 23.7778 watts. In addition, one VMJ cell was able to achieve a power density of 13.6 watts per cm2, at a conversion efficiency of 24 . These experiments confirm that the VMJ technology can withstand and utilize the high intensity laser energy without damage and/or significant reduction in the conversion efficienc