1,720,968 research outputs found
A Low-Cost Monitoring System and Operating Database for Quality Control in Small Food Processing Industry
No full textThe use of completely automated systems for collecting sensor data with the aim of monitoring and controlling the quality of small-scale food processes is not widespread. Small and micro-enterprises usually do not carry out their own precompetitive research or prototype development as regards to automation technologies. This study proposes a web-based, low-cost monitoring and supervisory control and data acquisition (SCADA) system whose kernel is available for free, as a possible solution that could be adopted by these food producers. It is mainly based on open SW/HW so as its configuration is adaptable to the application and type of plant. It presents a modular architecture and its main functionalities encompass the acquisition, management, aggregation and visualization of process data, providing an operating database. It also provides food tracking and process quality control: The time series are browsable due to QR-Code generation and different early warning detection strategies are implemented. A tool for solving migration problems based on Fick’s equation is offered as a packaging decision support system
Versatility of Vascularized Fibular Graft in Forearm Bone Loss: From Initial Treatment to Secondary Nonunion Treatment
Full text linkPurpose: Managing mangled forearms poses a considerable challenge for hand surgeons. The vascularized fibular graft (VFG) is a commonly used technique for addressing this complex issue. This retrospective study aims to assess the outcomes of advanced treatment for complex forearm bone loss necessitating microsurgical treatment with a vascularized fibula flap. Methods: Patients treated with VFG between January 2010 and December 2022 were included in this analysis. Physical and radiographic evaluations were performed for all patients, and they completed patient-reported outcome measures such as the disability of the arm, shoulder, and hand scores, Mayo Wrist scores, and visual analog scale pain (VAS-Pain) scores for both the recipient and donor sites. Patients treated with one-bone forearm (OBF) reconstruction were also assessed using the outcome score of the OBF according to Peterson. Results: A total of 26 cases were treated with VFG for forearm bone defect reconstruction (13 for primary treatment and 13 for secondary treatment of nonunion). Vascularized fibular graft was employed to create a OBF in four cases, a double barrel in three cases, and an osteocutaneous composite flap in nine cases. The average bone defect measured 81 ± 3.4 mm (range: 50–150 mm). Bone healing was achieved at an average of 8.3 ± 5.5 months (range: 4–15 months), with nonunion at one docking point observed in eight cases necessitating revision. At the follow-up end point, patients reported an average disability of the arm, shoulder, and hand score of 13.5%, a Mayo Wrist score of 80%, and a VAS-Pain score of 3/10. The VAS-Pain outcome at the donor site was rated at 4/10. One-bone forearm's mean score was 7/10. Conclusions: Vascularized fibular graft stands as a viable option for mangled forearm reconstruction. Whether through the double barrel technique or as an osteocutaneous composite graft, VFG allows for the simultaneous reconstruction of both forearm bones and associated soft tissue injuries. Type of study/level of evidence: Therapeutic IV
Principles of reconstruction. Like with like and flap thinning: two essential tools
Full text linkThe "like with like" and the "flap thinning" are two workhorse principles the surgeon must keep in mind to achieve a functional and cosmetic reconstruction of the hand. These principles are underpinned by a thorough knowledge of anatomy and functional hand units, with a wide range of reconstructive procedures that must be finalized to the necessity of the impaired structures. "Like with like" means that a lost tissue must be replaced with another one that can be compared in appearance and function. In addition, good cosmetic is often associated with good function because the complex attempt to get a proper aesthetic always traduces itself into a better functional reconstruction. "Flap thinning" is essential because soft tissue injuries of the hand represent a more difficult reconstructive challenge than similar injuries elsewhere, and the need for thin tissue to wrap the superficial noble structures of the hand is constant. However, the procedure of thinning a flap can be dangerous and must adhere to the vascular architecture of the flap. This paper aims to review and briefly summarize the current literature in this field
A Low Cost UWB Based Solution for Direct Georeferencing UAV Photogrammetry
Full text linkThanks to their flexibility and availability at reduced costs, Unmanned Aerial Vehicles (UAVs) have been recently used on a wide range of applications and conditions. Among these, they can play an important role in monitoring critical events (e.g., disaster monitoring) when the presence of humans close to the scene shall be avoided for safety reasons, in precision farming and surveying. Despite the very large number of possible applications, their usage is mainly limited by the availability of the Global Navigation Satellite System (GNSS) in the considered environment: indeed, GNSS is of fundamental importance in order to reduce positioning error derived by the drift of (low-cost) Micro-Electro-Mechanical Systems (MEMS) internal sensors. In order to make the usage of UAVs possible even in critical environments (when GNSS is not available or not reliable, e.g., close to mountains or in city centers, close to high buildings), this paper considers the use of a low cost Ultra Wide-Band (UWB) system as the positioning method. Furthermore, assuming the use of a calibrated camera, UWB positioning is exploited to achieve metric reconstruction on a local coordinate system. Once the georeferenced position of at least three points (e.g., positions of three UWB devices) is known, then georeferencing can be obtained, as well. The proposed approach is validated on a specific case study, the reconstruction of the façade of a university building. Average error on 90 check points distributed over the building façade, obtained by georeferencing by means of the georeferenced positions of four UWB devices at fixed positions, is 0.29 m. For comparison, the average error obtained by using four ground control points is 0.18 m
Finding spatial open data via web: a SWOT analysis
Full text linkIn the following paper we report the experience of frst-time users looking for
open data over a dedicated web portal which provides a catalog from third
party providers in different formats. A SWOT analysis is applied to assess how
accessible, intuitive and helpful were the tools and the data that are provided.
We provide constructive criticism on weaknesses and discuss tentative
solutions to problems encountered, which can be the starting point for further
improvement of such services
UAV positioning and collision avoidance based on rss measurements
Full text linkIn recent years, Unmanned Aerial Vehicles (UAVs) are attracting more and more attention in both the research and industrial communities: indeed, the possibility to use them in a wide range of remote sensing applications makes them a very flexible and attractive solution in both civil and commercial cases (e.g. precision agriculture, security and control, monitoring of sites, exploration of areas difficult to reach). Most of the existing UAV positioning systems rely on the use of the GPS signal. Despite this can be a satisfactory solution in open environments where the GPS signal is available, there are several operating conditions of interest where it is unavailable or unreliable (e.g. close to high buildings, or mountains, in indoor environments). Consequently, a different approach has to be adopted in these cases. This paper considers the use ofWiFi measurements in order to obtain position estimations of the device of interest. More specifically, to limit the costs for the devices involved in the positioning operations, an approach based on radio signal strengths (RSS) measurements is considered. Thanks to the use of a Kalman filter, the proposed approach takes advantage of the temporal dynamic of the device of interest in order to improve the positioning results initially provided by means of maximum likelihood estimations. The considered UAVs are assumed to be provided with communication devices, which can allow them to communicate with each other in order to improve their cooperation abilities. In particular, the collision avoidance problem is examined in this work
Solar Irradiance Modelling with NASA WW GIS Environment
Full text linkIn this work we present preliminary results regarding a proof-of-concept project which aims to provide tools for mapping the amount of solar radiation reaching surfaces of objects, accounting for obstructions between objects themselves. The implementation uses the NASA World Wind development platform (NASA WW) to model the different physical phenomena that participate in the process, from the calculation of the Sun’s position relative to the area that is being considered, to the interaction between atmosphere and solid obstructions, e.g., terrain or buildings. A more complete understanding of the distribution of energy from the Sun illuminating elements on the Earth’s surface adds value to applications ranging from planning the renewable energy potential of an area to ecological analyses
Photogrammetric reconstruction with Bayesian information
Full text linkNowadays photogrammetry and laser scanning methods are the most wide spread surveying techniques. Laser scanning methods usually allow to obtain more accurate results with respect to photogrammetry, but their use have some issues, e.g. related to the high cost of the instrumentation and the typical need of high qualified personnel to acquire experimental data on the field. Differently, photogrammetric reconstruction can be achieved by means of low cost devices and by persons without specific training. Furthermore, the recent diffusion of smart devices (e.g. smartphones) embedded with imaging and positioning sensors (i.e. standard camera, GNSS receiver, inertial measurement unit) is opening the possibility of integrating more information in the photogrammetric reconstruction procedure, in order to increase its computational efficiency, its robustness and accuracy. In accordance with the above observations, this paper examines and validates new possibilities for the integration of information provided by the inertial measurement unit (IMU) into the photogrammetric reconstruction procedure, and, to be more specific, into the procedure for solving the feature matching and the bundle adjustment problems
Implementation and assessment of two density-based outlier detection methods over large spatial point clouds
Full text linkSeveral technologies provide datasets consisting of a large number of spatial points, commonly referred to as point-clouds. These point datasets provide spatial information regarding the phenomenon that is to be investigated, adding value through knowledge of forms and spatial relationships. Accurate methods for automatic outlier detection is a key step. In this note we use a completely open-source workflow to assess two outlier detection methods, statistical outlier removal (SOR) filter and local outlier factor (LOF) filter. The latter was implemented ex-novo for this work using the Point Cloud Library (PCL) environment. Source code is available in a GitHub repository for inclusion in PCL builds. Two very different spatial point datasets are used for accuracy assessment. One is obtained from dense image matching of a photogrammetric survey (SfM) and the other from floating car data (FCD) coming from a smart-city mobility framework providing a position every second of two public transportation bus tracks. Outliers were simulated in the SfM dataset, and manually detected and selected in the FCD dataset. Simulation in SfM was carried out in order to create a controlled set with two classes of outliers: clustered points (up to 30 points per cluster) and isolated points, in both cases at random distances from the other points. Optimal number of nearest neighbours (KNN) and optimal thresholds of SOR and LOF values were defined using area under the curve (AUC) of the receiver operating characteristic (ROC) curve. Absolute differences from median values of LOF and SOR (defined as LOF2 and SOR2) were also tested as metrics for detecting outliers, and optimal thresholds defined through AUC of ROC curves. Results show a strong dependency on the point distribution in the dataset and in the local density fluctuations. In SfM dataset the LOF2 and SOR2 methods performed best, with an optimal KNN value of 60; LOF2 approach gave a slightly better result if considering clustered outliers (true positive rate: LOF2 = 59.7% SOR2 = 53%). For FCD, SOR with low KNN values performed better for one of the two bus tracks, and LOF with high KNN values for the other; these differences are due to very different local point density. We conclude that choice of outlier detection algorithm very much depends on characteristic of the dataset’s point distribution, no one-solution-fits-all. Conclusions provide some information of what characteristics of the datasets can help to choose the optimal method and KNN values
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