Designing and Testing an IoT Low-Cost PPP-RTK Augmented GNSS Location Device.

Nowadays, the availability of affordable multi-constellation multi-frequency receivers has broadened access to accurate positioning. The abundance of satellite signals coupled with the implementation of ground- and satellite-based correction services has unlocked the potential for achieving real-time centimetre-level positioning with low-cost instrumentation. Most of the current and future applications cannot exploit well-consolidated satellite positioning techniques such as Network Real Time Kinematic (RTK) and Precise Point Positioning (PPP); the former is inapplicable for large user bases due to the necessity of a two-way communication link between the user and the NRTK service provider, while the latter necessitates long convergence times that are not in keeping with kinematic application. In this context, the hybrid PPP-RTK technique has emerged as a potential solution to meet the demand for real-time, low-cost, accurate, and precise positioning. This paper presents an Internet of Things (IoT) GNSS device developed with low-cost hardware; it leverages a commercial PPP-RTK correction service which delivers corrections via IP. The main target is to obtain both horizontal and vertical decimetre-level accuracies in urban kinematic tests, along with other requisites such as solution availability and the provision of connection ports for interfacing an IoT network. A vehicle-borne kinematic test has been conducted to evaluate the device performance. The results show that (i) the IoT device can deliver horizontal and vertical positioning solutions at decimetre-level accuracy with the targeted solution availability, and (ii) the provided IoT ports are feasible for gathering the position solutions over an internet connection.

Unveiling the Dynamics of Thermal Characteristics Related to LULC Changes via ANN.

Continuous and unplanned urbanization, combined with negative alterations in land use land cover (LULC), leads to a deterioration of the urban thermal environment and results in various adverse ecological effects. The changes in LULC and thermal characteristics have significant implications for the economy, climate patterns, and environmental sustainability. This study focuses on the Province of Naples in Italy, examining LULC changes and the Urban Thermal Field Variance Index (UTFVI) from 1990 to 2022, predicting their distributions for 2030. The main objectives of this research are the investigation of the future seasonal thermal characteristics of the study area by characterizing land surface temperature (LST) through the UTFVI and analyzing LULC dynamics along with their correlation. To achieve this, Landsat 4-5 Thematic Mapper (TM) and Landsat 9 Operational Land Imager (OLI) imagery were utilized. LULC classification was performed using a supervised satellite image classification system, and the predictions were carried out using the cellular automata-artificial neural network (CA-ANN) algorithm. LST was calculated using the radiative transfer equation (RTE), and the same CA-ANN algorithm was employed to predict UTFVI for 2030. To investigate the multi-temporal correlation between LULC and UTFVI, a cross-tabulation technique was employed. The study's findings indicate that between 2022 and 2030, there will be a 9.4% increase in built-up and bare-land areas at the expense of the vegetation class. The strongest UTFVI zone during summer is predicted to remain stable from 2022 to 2030, while winter UTFVI shows substantial fluctuations with a 4.62% decrease in the none UTFVI zone and a corresponding increase in the strongest UTFVI zone for the same period. The results of this study reveal a concerning trend of outward expansion in the built-up area of the Province of Naples, with central northern regions experiencing the highest growth rate, predominantly at the expense of vegetation cover. These predictions emphasize the urgent need for proactive measures to preserve and protect the diminishing vegetation cover, maintaining ecological balance, combating the urban heat island effect, and safeguarding biodiversity in the province.

Low-Cost GNSS and PPP-RTK: Investigating the Capabilities of the u-blox ZED-F9P Module.

GNSS has become ubiquitous in high-precision applications, although the cost of high-end GNSS receivers remains a major obstacle for many applications. Recent advances in GNSS receiver technology have led to the development of low-cost GNSS receivers, making high-precision positioning available to a wider range of users. One such technique for achieving high-precision positioning is Precise Point Positioning-Real Time Kinematic (PPP-RTK). It is a GNSS processing technique that combines the PPP and RTK approaches to provide high-precision positioning in real time without the need for a base station. In this work, we aim to assess the performance of the low-cost u-blox ZED-F9P GNSS module in PPP-RTK mode using the low-cost u-blox ANN-MB antenna. The experiment was designed to investigate both the time it takes the receiver to resolve the phase ambiguity and to determine the positioning accuracies achievable. Results showed that the u-blox ZED-F9P GNSS module could achieve centimeter-level positioning accuracy in about 60 s in PPP-RTK mode. These results make the PPP-RTK technique a good candidate to fulfill the demand for mass-market accurate and robust navigation since uses satellite-based corrections to provide accurate positioning information without the need for a local base station or network. Furthermore, due to its rapid acquisition capabilities and accurate data georeferencing, the technique has the potential to serve as a valuable method to improve the accuracy of the three-S techniques (GIS, remote sensing, and GPS/GNSS).

Observation Quality Assessment and Performance of GNSS Standalone Positioning with Code Pseudoranges of Dual-Frequency Android Smartphones.

The new generation of Android smartphones is equipped with GNSS chips capable of tracking multi-frequency and multi-constellation data. In this work, we evaluate the positioning performance and analyze the quality of observations collected by three recent smartphones, namely Xiaomi Mi 8, Xiaomi Mi 9, and Huawei P30 pro that take advantage of such chips. The analysis of the GNSS observation quality implies that the commonly employed elevation-dependent function is not optimal for smartphone GNSS observation weighting and suggests an application of the C/N0-dependent one. Regarding smartphone code signals on L5 and E5a frequency bands, we found that they are characterized with noticeably lower noise as compared to E1 and L1 ones. The single point positioning results confirm an improvement in the performance when the weights are a function of the C/N0-rather than those dependent on the satellite elevation and that a smartphone positioning with E5a code observations significantly outperforms that with E1 signals. The latter is expressed by a drop of the horizontal RMS from 8.44 m to 3.17 m for Galileo E1 and E5a solutions of Xiaomi Mi 9 P30, respectively. The best positioning accuracy of multi-GNSS single-frequency (L1/E1/B1/G1) solution was obtained by Huawei P30 with a horizontal RMS of 3.24 m. Xiaomi Mi 8 and Xiaomi Mi 9 show a horizontal RMS error of 4.14 m and 4.90 m, respectively.

Advantages of Damage Control Strategy With Abdominal Negative Pressure and Instillation in Patients With Diffuse Peritonitis From Perforated Diverticular Disease.

Purpose. To evaluate the results of Damage Control Strategy (DCS) in the treatment of generalized peritonitis from perforated diverticular disease in patients with preoperative severe systemic diseases. Methods. All the patients with diffuse peritonitis (Hinchey 3 and 4) and the American Society of Anesthesiologists (ASA) score ≥3 were included and underwent DCS consisting of a 2-step procedure. The first was peritoneal lavage, perforated colon-stapled resection, and temporary abdominal closure with negative pressure wound therapy combined with instillation. The second step, 48 hours later, included the possibility of restoring intestinal continuity basing on local and general patients' conditions. Results. Thirty patients (18 [60%] women and 12 [40%] men, median age 68.5 [range = 35-84] years) were included (18 [60%] ASA III, 11 [36.7%] ASA IV, and 1 [0.03%] ASA V). Seven patients (23.3%) showed sepsis and 1 (3.33%) septic shock. At second surgery, 24 patients (80%) received a colorectal anastomosis and 6 patients (20%) underwent a Hartmann's procedure. Median hospital stay was 18 days (range = 12-62). Postoperative morbidity rate was 23.3% (7/30) and included 1 anastomotic leak treated with Hartmann's procedure. Consequently, at discharge from hospital, 23 patients (76.6%) were free of stoma. Primary fascial closure was possible in all patients. Conclusions. DCS with temporary abdominal closure by negative pressure wound therapy combined with instillation in patients with diffuse peritonitis from complicated diverticulitis could represent a feasible surgical option both in hemodynamically stable and no stable patients, showing encouraging results including a low stoma rate and an acceptable morbidity rate.

Signal in Space Error and Ephemeris Validity Time Evaluation of Milena and Doresa Galileo Satellites.

In August 2016, Milena (E14) and Doresa (E18) satellites started to broadcast ephemeris in navigation message for testing purposes. If these satellites could be used, an improvement in the position accuracy would be achieved. A small error in the ephemeris would impact the accuracy of positioning up to ±2.5 m, thus orbit error must be assessed. The ephemeris quality was evaluated by calculating the SISEorbit (in orbit Signal In Space Error) using six different ephemeris validity time thresholds (14,400 s, 10,800 s, 7200 s, 3600 s, 1800 s, and 900 s). Two different periods of 2018 were analyzed by using IGS products: DOYs 52-71 and DOYs 172-191. For the first period, two different types of ephemeris were used: those received in IGS YEL2 station and the BRDM ones. Milena (E14) and Doresa (E18) satellites show a higher SISEorbit than the others. If validity time is reduced, the SISEorbit RMS of Milena (E14) and Doresa (E18) greatly decreases differently from the other satellites, for which the improvement, although present, is small. Milena (E14) and Doresa (E18) reach a SISEorbit RMS of about 1 m (comparable to that of the other Galileo satellites reach with the nominal validity time) when validity time of 1800 s is used. Therefore, using this threshold, the two satellites could be used to improve single point positioning accuracy.

Analysis of the factors influencing the outcome of bleeding of the lower digestive tract. A report of 15 consecutives cases.

The authors present a series of 15 patients with lower gastrointestinal bleeding. 11 (73%) out of 15 patients, were directly subjected to surgery, and 4 (37%) attempted to stop hemorrhage with angiography. In the group of patients undergoing surgery we had a mortality of 1 out of 12 (8%). In the group of patients undergoing embolization, two of four died with 50% of mortality. All patients undergoing surgery had received from a minimum of two to a maximum of four blood bags before surgery. 8 out of 12 patients (67%) received more than two bags. In 10 (67%) out of 15 patients TC scan preoperatively identified the site of bleeding. 10 cases out of 15 patients was evident Anticoagulant or antiplatelet use. In the group of patients undergoing surgical treatment with haemorrhage stopping 60% (6 out of 10) did not take these drugs. No patient had significant alterations to the INR value. Patients undergoing Surgical treatment without haemorrhage stopping had an average age significantly higher than the group with haemorrhage stopping (84 aa vs 54.2). In this group CT scan had identified the source of bleeding in one patient on two (50%) and all patients In the group of deceased patients, the average age was 78 aa, the tac had never identified the site of bleeding, and all had antiaggregates. In the group of deceased patients, the average age was 78 aa, CT scan had never identified the site of bleeding, and all In the group of deceased patients, the average age was 78 aa, the tac had never identified the site of bleeding, and all had antiaggregates KEY WORDS: Lower gastrointestinal bleeding, Prognostic factors, Surgical management.

Negative pressure therapy alone or with irrigation in the management of severe peritonitis.

BACKGROUND: Ogilvie was the first to publish on open abdomen (OA) for the treatment of the damages caused by penetrating abdominal wounds in war events. Research improved those devices that allow a controlled, homogeneous and continuous extraction of contaminated fluids from all abdominal recesses, which are nowadays the base of the "Open Abdomen" technique. MATERIALS AND METHODS: From August 2012 to February 2016 at the Department of Emergency Surgery of Cardarelli Hospital in Naples, 40 patients affected by Severe Peritonitis have been treated with OA technique. 13 (32,5%) were treated with only the suction-drainage system, 27 patients (67,5%) were treated with suction drainage and irrigation system. Abthera® device was used in all patients. RESULTS: The duration of treatment was 15 days in the first group, with 7 device's substitutions, while in the second group it was about 10 days with 4 substitutions At the end of the procedure we were able to perform primary fascia closure in 7 cases (53,8%) in the first group and in 23 cases (85.2%) in the second group. 4 patients (30,8%) died in the first group, and 7 (26%) in the second. CONCLUSION: The suction/irrigation method seems to be appropriate to use in case of a surgical emergency that causes severe peritonitis. It is associated not only with lower death rates but also with better parameters, that are more frequently worse during prolonged treatments. Irrigation of abdominal cavity causes also less retraction of fascia recti which leads to a higher rate of direct fascia closure. Key Words: Emergency surgery, Irrigation, Open abdomen, Peritonitis.

Acute symptomatic Meckel diverticulum management. Our experience on seven consecutive cases.

Meckel's diverticulum (MD ) is the most common congenital anomaly of the gastrointestinal tract. We revalued clinical records of patients discharged from Unit of Urgent and General Surgery of Highly Specialized Hospital "A.O.R.N. Antonio Cardarelli" of Naples with diagnosis of acute pathology associated to complicated MD from 1(st) January 2011 to 30(th) November 2012. Seven consecutive cases have been chosen: five males (71,4%) and two females (28,6%). The age ranges over from 13 to 50 years with a 28 years average. Four of them were submitted to emergency surgical intervention for hemorrhage from gastro-enteric tract (57%), two for bowel obstruction (29%) and one for acute appendicitis (14%). In all cases sample was send to histological examination. Two samples showed normal epithelial mucosa. Four of them showed ectopic mucosa inside the diverticulum: three gastric and one pancreatic ectopic mucosa focal areas. The last case showed normal epithelial cells but with ulcerated and hemorrhagic areas. Four samples of patients with hemorrhage from gastroenteric tract showed at histological examination: a case of normal mucosa, a case of gastric mucosa areas, one of pancreatic ectopic tissue and the last with normal mucosa but ulcerated and with bleeding areas.In our experience we never speculated that acute symptomatology depended on complicated MD and diagnosis was always done during laparotomy. We think that MD removal is always the correct choice, so that future complications such as neoplasm can be avoided. MD simple resection by Stapler at the base of diverticulum is the correct choice.

Surgical treatment of non-variceal upper gastrointestinal bleeding: our experience with 1482 patients.

We retrospectively evaluated the medical records of patients admitted to the U.O.C. of General and Emergency Surgery with Surgical and Polyspecialistic Observation of the Emergency Unit of A.O.R.N. A. Cardarelli of Naples for non-variceal upper gastrointestinal bleeding from 2003 to 2006. All data regarding patients submitted to surgery for non-variceal upper gastrointestinal bleeding were collected including the number of patients submitted to surgery after failure of the endoscopic procedure, the diseases most frequently requiring surgery, the endoscopic and surgical procedures most frequently used, and the reasons that prompted the surgical procedure. Of 1482 patients admitted for non-variceal upper gastrointestinal bleeding the lesions that most frequently required surgery were peptic ulcer disease complicated by bleeding in 31 patients (70.5%) and cancer in 13 (29.5%). The most frequent surgical procedure was subtotal gastrectomy (17 patients [38.6%]), followed by direct haemostasis of the ulcer (13 patients [29.5%]), total gastrectomy (11 patients [25%]), and ulcer excision (3 patients [6.9%]). Subtotal or total gastrectomy is the surgical procedure of choice in patients with non-variceal upper gastrointestinal bleeding after failure of endoscopic treatment. The indication for gastrectomy should be determined on the basis of the patient's haemodynamic condition.

[Use of Permacol in complicated incisional hernia]. / L'impiego del Permacol nei laparoceli complicati.

Polypropylene mesh repair is the gold standard for primary inguinal hernia and incisional hernia. Wound infection and small bowel fistulas are contraindications to polypropylene mesh repair. In addition, synthetic meshes are known to cause severe peritoneal adhesions and enteric fistulas if located close to the bowel. Porcine intestinal submucosa has been used successfully in experimental studies in dogs and rats to repair large abdominal wall defects. A new porcine dermal collagen graft has been used in man for groin hernia repair, incisional hernia repair and other surgical procedures without complications. We describe 6 cases of complicated incisional hernia operated in emergency using porcine dermal collagen grafts. In one woman the incisional hernia was associated with an enterovaginal fistula. Three cases presented severe wound infections, two of which related to a previous polypropylene mesh repair, while another had an irreducible recurrent incisional hernia and one woman presented complete evisceration. None of the patients had postoperative or porcine-graft-related complications. Over a follow-up period of 3-24 months we have had no recurrence or wound infection. The results of these few cases confirm the safety and efficacy of the porcine dermal collagen mesh also in incisional hernia repair.