Adaptive analysis of thermal comfort in university classrooms: correlation between experimental data and mathematical models

Numerous studies are in progress to support adaptive models and to establish quantitative indexes to allow the subject to optimize his comfort conditions. With the aim of finding possible correlations between experimental data and experimental surveys for moderate environments, such as university classrooms, a multiple response questionnaire was elaborated, comprehensive of information for the static and adaptive model proposed by UNI-EN-ISO 10551. The questionnaire was applied in autumn, winter and spring in classrooms of the University of Perugia, Pavia and Terni. During the campaign, all data needed to calculate both Fanger and Wray comfort indices were acquired by instrumental surveys and questionnaire compilation. By means of results analysis the following couple of parameters were correlated: Predicted Mean Vote (PMV) versus the difference between the Equivalent Uniform Temperature and the Comfort Uniform Temperature (Teu - Tu) and the Predicted Percentage of Dissatisfied (PPD) versus the absolute value of the same difference between temperatures (|Teu - Tu|). For the first couple of parameters a linear correlation was found while for the second one a second degree polynomial relation was obtained. Finally values of Operative Temperature T0 and Equivalent Uniform Temperature Teu, obtained for each single experimental survey were compared, observing a very good agreement between the two quantities, with differences that exceed 0.1 K only for a few number of values

A design oriented fibre-based model for simulating the long-term behaviour of RC beams: Application to beams cast in different stages

The present paper describes a numerical model that has been developed in order to analyse the long-term behaviour of beams built in different stages under serviceability loads, considering the effect of delayed deformations due to creep and shrinkage. The rheological model for concrete creep is based on a modified version of the solidification theory while the cross section behaviour is described by means of a fibre model. The paper discusses the performances of the model in simulating the behaviour of two fullscale beams tested by the authors

CCD photometry of 2060 Chiron, 1991 January

Observations of 2060 Chiron was performed on 7 to 8 Jan. 1991 with the Mt. Palomar 1.52 m telescope in the Gunn-R passband. On-chip field stars were used to perform differential reductions. The repeatability of the 5.9 hour light curve was excellent, both within a night and from night to night. No evidence for short-term secular variations similar to those seen last year by both Luu and Jewitt (1990) and Buratti and Dunbar (1991) is seen in the new light curve. Chiron's rotational light curve appears strikingly similar to that obtained a year earlier by Luu and Jewitt (1990), both in amplitude and shape. Both light curves show strongly correlated changes over a timescale of perhaps 15 minutes. These same features were marginally visible in the 1986 light curve. Such behavior is believed to be evidence that Chiron may be more aspherical than the 4 percent intensity variation might otherwise indicate, and favors a viewing geometry where the subearth latitude is rather low. Chiron was much fainter in 1985, when a partial light curve was obtained by Marcialis. Due to the lower sampling rate of these early data, no conclusions can be made regarding the high-frequency light curve structure back then. All three of these light curves differ significantly from that obtained by Buratti and Dunbar (1991), one week before the observations of Luu and Jewitt. The Chiron field was calibrated using Landolt standards on Ut 15 Mar. 1991. A mean R-magnitude of 15.6 + or - 0.1 was found. Variability of 2060 Chiron was demonstrated over timescales of minutes, hours, and years. An intense campaign was urged to monitor the photometric behavior of Chiron throughout the 1990s

Performance analysis of multi-hop framed ALOHA systems with virtual antenna arrays

We consider a multi-hop virtual multiple-input-multiple-output system, which uses the framed ALOHA technique to select the radio resource at each hop. In this scenario, the source, destination and relaying nodes cooperate with neighboring devices to exploit spatial diversity by means of the concept of virtual antenna array. We investigate both the optimum number of slots per frame in the slotted structure and once the source-destination distance is fixed, the impact of the number of hops on the system performance. A comparison with deterministic, centralized re-use strategies is also presented. Outage probability, average throughput, and energy efficiency are the metrics used to evaluate the performance. Two approximated mathematical expressions are given for the outage probability, which represent lower bounds for the exact metric derived in the paper

A 2.4 GHz LoRa-Based Protocol for Communication and Energy Harvesting on Industry Machines

The fourth industrial revolution is paving the way for Industrial Internet of Things applications where large number of wireless nodes, equipped with sensors and actuators, monitor the production cycle of industrial goods. This paper proposes and analyses LoRaIN, a network architecture and MAC-layer protocol thought for on-demand monitoring of industrial machines. Our proprietary system is an energy-efficient, reliable and scalable solution, where the protocol is built on top of LoRa at 2.4 GHz. Indeed, the low-power characteristics of LoRa allow to reduce energy consumption, while Wireless Power Transfer is used to recharge batteries, avoiding periodic battery replacement. High reliability is obtained through the joint use of Frequency and Time Division Multiple Access. A dynamic LoRaIN scheduler manages the communication and recharging phases depending on the tasks assigned to the nodes, as well as the number of monitoring devices. Performance is measured in terms of network throughput, energy consumption and latency. Results demonstrate that the proposed solution is suitable for monitoring applications of industry machines

Thermal Comfort Evaluation Within Non-residential Environments: Development of Artificial Neural Network by Using the Adaptive Approach Data☆

Abstract A new algorithm for the PMV calculation was developed using Artificial Neural Networks. Several experimental investigations were carried out in two classrooms using both Fanger static model and adaptive approaches for the PMV evaluation. The Artificial Neural Network was trained considering a few input parameters; specifically for the network development only the air temperature and relative humidity were considered as experimental data. This algorithm allows to correlate the thermal sensation to both indoor and outdoor factors and it is a useful tool for predicting the PMV index, replacing the traditional methods with less time and cost demanding

Apprendistato: quadro comparato e buone prassi

Il volume affronta da un punto di vista comparato gli aspetti principali connessi al contratto di apprendistato. Il punto di partenza sono le analisi e gli spunti offerti dalle istituzioni comunitarie per una maggiore diffusione dei rapporti di apprendistato, in un’ottica di aumento dell’occupazione giovanile e di contrasto alla dispersione scolastica. La pubblicazione mette in relazione cinque aspetti: definizione e ruolo dell’apprendistato; soggetti regolatori; retribuzione; durata del percorso; monte ore formativo. Per ciascuna di queste voci si evidenziano le peculiarità dei sistemi in vigore in Italia, Francia, Spagna, Regno Unito, Germania, Danimarca e Svezia

On the performance of a uav-aided wireless network based on nb-iot

In recent years, interest in Unmanned Aerial Vehicles (UAVs) as a means to provide wireless connectivity has substantially increased thanks to their easy, fast and flexible deployment. Among the several possible applications of UAV networks explored by the current literature, they can be efficiently employed to collect Internet-of-Things (IoT) data because the non-stringent latency and small-size traffic type is particularly suited for UAVs’ inherent characteristics. However, the implications coming from the implementation of existing technology in such kinds of nodes are not straightforward. In this article, we consider a Narrow Band IoT (NB-IoT) network served by a UAV base station. Because of the many configurations possible within the NB-IoT standard, such as the access structure and numerology, we thoroughly review the technical aspects that have to be implemented and may be affected by the proposed UAV-aided IoT network. For proper remarks, we investigate the network performance jointly in terms of the number of successful transmissions, access rate, latency, throughput and energy consumption. Then, we compare the obtained results on different and known trajectories in the research community and study the impact of varying UAV parameters such as speed and height. Moreover, the numerical assessment allows us to extend the discussion to the potential implications of this model in different scenarios. Thus, this article summarizes all the main aspects that must be considered in planning NB-IoT networks with UAVs

Influence of Cooking Conditions on Nutritional Properties and Sensory Characteristics Interpreted by E-Senses: Case-Study on Selected Vegetables

This study investigates the effects of three cooking methods (boiling, steaming and microwaving) on the nutritional and physical properties of cauliflowers, carrots and sweet potatoes; e-senses were applied to interpret the sensory characteristics according to physico-chemical aspects. The nutritional quality was evaluated by determining the concentrations of key components and the antioxidant activity; e-sense data, combined with texture parameters, were processed by a principal component analysis. The cooking method and time significantly influenced the quality of the three products. Boiling, which detrimentally affected ascorbic acid, total phenolic concentration and antioxidant activity, enhanced carotene accessibility. Steaming produced losses in ascorbic acid, increasing total phenolics and carotenoids. Microwaving resulted in minor changes in ascorbic acid concentrations, preserved carotenoids and increased total phenolics. The nutritional quality was better preserved or enhanced using shorter cooking times. The elaboration of the data collected by the e-senses showed a clear evolution according to the cooking method and time. The results helped to determine the cooking method that best preserves the nutritional properties of the vegetables, highlighting the applicability of rapid instrumental methods to interpret the evolution of sensory characteristics

Trajectories and resource management of flying base stations for C-V2X

In a vehicular scenario where the penetration of cars equipped with wireless communication devices is far from 100% and application requirements tend to be challenging for a cellular network not specifically planned for it, the use of unmanned aerial vehicles (UAVs), carrying mobile base stations, becomes an interesting option. In this article, we consider a cellular-vehicle-to-anything (C-V2X) application and we propose the integration of an aerial and a terrestrial component of the network, to fill the potential unavailability of short-range connections among vehicles and address unpredictable traffic distribution in space and time. In particular, we envision a UAV with C-V2X equipment providing service for the extended sensing application, and we propose a UAV trajectory design accounting for the radio resource (RR) assignment. The system is tested considering a realistic scenario by varying the RRs availability and the number of active vehicles. Simulations show the results in terms of gain in throughput and percentage of served users, with respect to the case in which the UAV is not present