Low-cost, high-resolution, fault-robust position and speed estimation for PMSM drives operating in safety-critical systems

In this paper it is shown how to obtain a low-cost, high-resolution and fault-robust position sensing system for permanent magnet synchronous motor drives operating in safety-critical systems, by combining high-frequency signal injection with binary Hall-effect sensors. It is shown that the position error signal obtained via high-frequency signal injection can be merged easily into the quantization-harmonic-decoupling vector tracking observer used to process the Hall-effect sensor signals. The resulting algorithm provides accurate, high-resolution estimates of speed and position throughout the entire speed range; compared to state-of-the-art drives using Hall-effect sensors alone, the low speed performance is greatly improved in healthy conditions and also following position sensor faults. It is envisaged that such a sensing system can be successfully used in applications requiring IEC 61508 SIL 3 or ISO 26262 ASIL D compliance, due to its extremely high mean time to failure and to the very fast recovery of the drive following Hall-effect sensor faults at low speeds. Extensive simulation and experimental results are provided on a 3.7 kW permanent magnet drive

Recent Trends and Impacts of Fisheries Exploitation on Mediterranean Stocks and Ecosystems

This review focuses on the recent data on Mediterranean fishing fleets and landings, results from stock assessments and ecosystem models to provide an overview of the multiple impacts of fishing exploitation in the different Mediterranean geographical sub-areas (GSAs). A fleet of about 73,000 vessels is widespread along the Mediterranean coasts. Artisanal activities are predominant in South Mediterranean and in the eastern basin, while trawling features GSAs in the western basin and the Adriatic Sea. The overall landings of fish, crustaceans and cephalopods, after peaking during mid 90s at about one million tons, declined at about 700,000 tons in 2013. However, while landings are declining in EU countries since the 90s, in non-EU countries a decreasing trend was observed only in the last 5–10 years. The current levels of fishing effort determine a general overexploitation status of commercial stocks with more than 90% of the stock assessed out of safe biological limits. Indicators obtained from available ecosystem models were used to assess the sustainability of the fisheries. They included primary production required to sustain fisheries (PPR), mean trophic level of the catch (mTLc), the loss in secondary production index (L index), and the probability of the ecosystem to be sustainably exploited (psust). In areas exploited more sustainably (e.g., Gulf of Gabes, Eastern Ionian, and Aegean Sea) fishing pressure was characterized by either low number of vessels per unit of shelf area or the large prevalence of artisanal/small scale fisheries. Conversely, GSAs in Western Mediterranean and Adriatic showed very low ecosystem sustainability of fisheries that can be easily related with the high fishing pressure and the large proportion of overfished stocks obtained from single species assessments. We showed that the current knowledge on Mediterranean fisheries and ecosystems describes a worrisome picture where the effect of poorly regulated fisheries, in combination with the ongoing climate forcing and the rapid expansion of non-indigenous species, are rapidly changing the structure and functioning of the ecosystem with unpredictable effects on the goods and services provided. Although this would call for urgent conservation actions, the management system implemented in the region appears too slow and probably inadequate to protect biodiversity and secure fisheries resources for the future generations

Širenje invazivnih školjkaša Anadara kagoshimensis i Anadara transversa u sjevernom i srednjem Jadranu

Two non-indigenous invasive bivalve species, Anadara kagoshimensis (Tokunaga, 1906) and Anadara transversa (Say, 1822), were recorded for the first time in the open waters of the eastern Adriatic Sea trawling grounds. Samples of these species were collected in 2008–2011 with modified beam trawl (rapido) during the SoleMon project, a project aimed at investigating the northern and central Adriatic Sea. In the years following its first record in 2008, the abundance of A. kagoshimensis increased in the area of investigation off the Istrian coast. The highest recorded abundance index per station was 1089 N km-2 in 2011. Species was present at depths from 31 to 41.5 m. Presence of Anadara transversa was recorded only at one station in 2011, in the middle of the open Adriatic between 70 and 72.5 m depth. The possible vectors of invasion of these species, from the western Adriatic coast to the eastern, are discussed.Dvije strane invazivne vrste školjkaša, Anadara kagoshimensis (Tokunaga, 1906) i Anadara transversa (Say, 1822), su po prvi put zabilježene u otvorenim vodama na koćarskim dnima u istočnom dijelu Jadranskoga mora. Uzorci ovih vrsta su sakupljeni za vrijeme SoleMon porojekta kojim je istraživano područje sjevernog i srednjeg Jadrana, u razdoblju od 2008. do 2011., a korišten je modificirani rampon (rapido). U godinama koje su slijedile nakon prve zabilješke 2008., abundancija vrste A. kagoshimensis se povećala na području istraživanja otvorenih voda uz obalu Istre. Najveća zabilježena vrijednost indeksa abundancije po postaji je bila 1089 N km-2, a zabilježena je 2011. godine. Vrsta je bila prisutna na dubinama od 31 do 41,5 m. Prisutnost vrste Anadara transversa je zabilježena samo na jednoj postaji 2011., u otvorenom Jadranu, na dubinama od 70 do 72,5 m. Analizirani su mogući vektori širenja ovih invazivnih vrsta sa zapadne obale Jadrana na istočnu

Edad y crecimiento del rascacio, Scorpaena porcus (Pisces: Scorpaenidae) en estructuras artificiales y arrecifes naturales en el mar Adriático

Age and growth of the black scorpionfish, Scorpaena porcus, were estimated for different populations inhabiting natural reefs and artificial structures (artificial reefs and offshore gas platforms) in the northwestern Adriatic Sea. Annual growth increment counts were carried out on sagittal otoliths of 415 specimens ranging from 80 to 280 mm TL. The accuracy of age estimates was assessed by testing the annual deposition of annuli and the location of the first annulus by marginal increment analysis and daily growth increment counts, respectively. As commonly observed in other scorpaenids, annuli consisted of an alternating pattern of opaque and translucent zones. Marginal increment analysis confirmed that annuli are formed once a year, with opaque zones laid down in spring-summer and translucent zones laid down in autumn-winter. The precision of age estimates was tested by applying both the average percent error (APE) and the mean coefficient of variation (CV). The maximum age estimated for the whole sampled populations was 8 years. The von Bertalanffy growth curves were separately fitted for natural and artificial reef populations of S. porcus. The likelihood ratio test indicated that the overall von Bertalanffy growth curves differed significantly between the two populations. The instantaneous growth rate (k, year-1) and asymptotic length (L∞, cm) were 0.23 and 22.30 and 0.53 and 20.13 for natural and artificial reef populations, respectively. Compared with natural reef population, populations of S. porcus inhabiting artificial reefs and, particularly, offshore platforms, were characterized by larger and older fish. However, young-of-the-year were completely absent from the platform habitats. The effects of artificial structures on S. porcus populations in the study area are discussed in the light of previous results on scorpionfish living in other areas.Se estimó la edad y crecimiento del rascacio, Scorpaena porcus, de diferentes poblaciones de arrecifes naturales y estructuras artificiales (arrecifes artificiales y plataformas de gas a mar abierto) en el noroeste del mar Adriático. Los contajes de los incrementos de crecimiento anuales se realizaron en otolitos sagitta de 415 especímenes entre 80 y 280 mm de longitud total. La precisión de la estima de la edad se evaluó comprobando la formación anual de los anillos, y la localización del primer anillo mediante análisis de incrementos marginales y contajes de incrementos diarios, respectivamente. Tal como es comúnmente observado, los anillos presentan un patrón de zonas opacas y translúcidas que van alternando. El análisis de incrementos marginales confirmó que los anillos se forman una vez al año, con las zonas opacas que se depositan en primavera-verano y las translúcidas en otoño-invierno. La precisión en la estima de las edades se comprobó aplicando el porcentaje de error promedio y el coeficiente promedio de variación (CV). La edad máxima estimada para todas las poblaciones muestreadas fue de ocho años. Las curvas de crecimiento de von Bertalanffy growth se ajustaron separadamente para las poblaciones de S. porcus de arrecifes naturales y artificiales. El test de verosimilitud indicó que las curvas de crecimiento de von Bertalanffy diferían significativamente entre las dos poblaciones. La tasa instantánea de crecimiento (k, año-1) y la longitud asintótica (L∞, cm) fueron 0.23 y 22.30 y 0.53 y 20.13 para poblaciones de arrecifes naturales y artificiales, respectivamente. En comparación con las poblaciones de S. porcus de arrecifes naturales, las que se encuentran en arrecifes artificiales y, en particular en plataformas a mar abierto, se caracterizaron por peces más grandes y de más edad. No obstante, los individuos de edad inferior a un año están completamente ausentes en dichas plataformas. El efecto de estructuras artificiales en las poblaciones de S. porcus en el área de estudio se discuten en función de resultados previos de scorpeniformes de otras áreas

Predictors of Emergency Room Access and Not Urgent Emergency Room Access by the Frail Older Adults

Background: Emergency rooms (ERs) overcrowded by older adults have been the focus of public health policies during the recent COVID-19 outbreak too. This phenomenon needed a change in the nursing care of older frail people. Health policies have tried to mitigate the frequent use of ER by implementing community care to meet the care demands of older adults. The present study aimed to investigate the predictors of emergency room access (ERA) and not-urgent emergency room access (NUERA) of community-dwelling frail older adults in order to provide an indication for out-of-hospital care services.Method: Secondary analysis of an observational longitudinal cohort study was carried out. The cohort consisted of 1,246 community-dwelling frail older adults (over 65 years) in the Latium region in Italy. The ER admission rate was assessed over 3 years from the administration of the functional geriatric evaluation (FGE) questionnaire. The ordinal regression model was used to identify the predictors of ERA and NUERA. Moreover, the ERA and NUERA rate per 100 observations/year was analyzed.Results: The mean age was 73.6 (SD +/- 7.1) years, and 53.4% were women. NUERAs were the 39.2% of the ERAs; robust and pre-frail individuals (79.3% of the sample) generated more than two-third of ERAs (68.17%), even if frails and very frails showed the higher ER rates per observation/year. The ordinal logistic regression model highlighted a predictive role on ERAs of comorbidity (OR = 1.13, p < 0.001) and frailty level (OR = 1.29; p < 0.001). Concerning NUERAs, social network (OR 0.54, P = 0.015) and a medium score of pulmo-cardio-vascular function (OR 1.50, P = 0.006) were the predictors.Conclusion: Comorbidity, lack of social support, and functional limitations increase both ERA and NUERA rates generated by the older adult population. Overall, bio-psycho-social frailty represents an indicator of the frequency of ERAs. However, to reduce the number of ERAs, intervention should focus mainly on the robust and pre-frail needs for prevention and care

Novi nalaz šaruna golemog, Trachurus picturatus T. E. Bowdich, 1825 (Osteichthyes: Carangidae) u sjevernom Jadranu

The observation of a new species in a new area represents the first opportunity to follow and study the dynamics of colonization and understand how a new species arrives, what are its movements and its potential impact. The discovery of a large number of species outside their usual area of distribution is probably the most important reason for the increase in perceived biodiversity of the Adriatic ichthyofauna. A total of 4 specimens of T. picturatus were caught in the period May-June 2011 in the surroundings of an offshore gas platform in the Northern Adriatic Sea. Scientific literature depicts this species as rare in the Adriatic Sea, indicating and suggesting the Pomo Pit (Central Adriatic Sea) as the Northern latitudinal limit of its distribution. On this basis, this paper reports the first record of T. picturatus in the Northern Adriatic basin, suggesting an expansion of its spatial distribution.Promatranje nove vrste u novom prostoru predstavlja prvu priliku praćenja i proučavanja dinamike kolonizacije, te razumijevanje kako nova vrsta pristiže u prostor, kako se u njemu kreće i njen potencijalni utjecaj na prostor. Otkriće velikog broja vrsta izvan njihovog uobičajenog područja raspodjele je vjerojatno najvažniji razlog za povećanje percipirane bioraznolikosti Jadranske ihtiofaune. Ukupno 4 primjerka šaruna golemog, T. picturatus, su ulovljeni u razdoblju od svibnja do lipnja 2011. u okolici platformi plina u sjevernom Jadranu. Znanstvena literatura opisuje ove vrste kao rijetke u Jadranu, što potvrđuje Jabučku kotlinu (srednjeg Jadrana) kao sjevernu granicu njegove raspodjele. Na temelju toga, u ovom radu se iznosi prvi nalaz šaruna golemog, T. picturatus, u sjevernom jadranskom slivu, što ukazuje na širenje njegove prostorne raspodjele

Assessment of the current status and effectiveness of area-based conservation measures banning trawling activities in the Adriatic Sea

The marine environment is highly stressed by anthropogenic pressures, among which fisheries, and in particular bottom trawling, are one of the main sources of impact. Area-based conservation measures can help conserve and restore ecosystems and population structures and therefore constitute a key tool to the achievement of the 14th Sustainable Development Goal, preservation of the ocean. The purpose of this paper is to provide an assessment of the compliance of area-based conservation measures. The Adriatic Sea has been selected as a case study area, as one of the most intensively trawled areas in the world where different countries share its resources and consequently different management strategies are put in place. We present a review of the marine managed areas established in the Adriatic Sea in 2019, providing information on their characteristics, temporal variabilities, and scopes. Through the processing of Automatic Identification System (AIS) data, the monthly bottom fishing activity performed within each area was inferred and the intensity was assessed. Thus, the effectiveness of trawling bans was evaluated. We demonstrated that full respect of the prohibition was effective in 73% of the areas, while trawling activity was recorded with different intensities in 149 out of 549 managed areas

Biometrijska i biološka integrativna studija o boljem gospodarskom upravljanju morskim pužem, Nassarius mutabilis (Linnaeus, 1758)

Fishing of Nassarius mutabilis is by far the most important activity carried out by artisanal fisheries in the central and northern Adriatic Sea, accounting for more than 35% of total fishing effort and yielding from 2000 to 3000 t of landings each year. This gastropod is targeted from the beginning of autumn to the end of spring using basket traps. Despite its importance under a socio-economic point of view, the scientific studies on the biology and ecology of this species are very scarce and the failure of the current management measures could also be attributed to the scarce knowledge on the biology of this species in the area. Taking this statement into consideration, the results of the present study contribute to fill a few existing gaps and may be useful to improve the management measures currently in force. Samples were collected from March 2006– March 2008 during monthly fishing surveys and carried out using basket traps in the central Adriatic Sea. A total of 383 males (size range 7–29 mm SH) and 504 females (size range 15-32 mm SH) were caught. Mean SH (± SD) of males was 15.84±3.57 mm and mean SH of females was 25.31±3.06 mm. A significant difference in the biometric characteristics between the two sexes was discovered. The condition index (CI) showed similar seasonal trends for both sexes, with a decrease from late winter to spring followed by an increase from summer to fall - early winter. The minimum values were recorded in summer and the maximum ones in winter, following an opposite trend in respect to water temperature. In the males this trend was observed starting from size classes larger than 11 mm SH, hence this size might be very close to the size at first sexual maturity. The size at first maturity hypothesized for females (16-20 mm SH) agrees with the minimum landing size (MLS) currently established for this species (20 mm SH). The absence of small females (SH 23 mm) leads to suppose a sex reversal from male to female at around 20 mm SH. On this basis, the management measure of MLS leads to the selective retention of females and, hence, to a sexual gap between the two sexes with possible consequences on the biology of the species and the resilience of the stock. The peaks of CI observed for males and females confirmed that the spawning season of this gastropod occurs in late winter – early spring, according to the abundant presence of egg capsules attached to submerged substrates in that period at sea. Consequently, from a management point of view, it would be advisable to shorten the fishing season that at present extends from fall to later spring.Lovljenje morskog puža Nassarius mutabilis je daleko najvažnija djelatnost malog priobalnog ribolova u središnjem i sjevernom Jadranu, što čini više od 35% ukupnog ribolovnog napora s prinosom od 2000 do 3000 tone svake godine. Ovaj puž se lovi od početka jeseni do kraja proljeća pomoću vrše. Unatoč njegovoj društveno-ekonomskoj važnosti, znanstvene studije o biologiji i ekologiji ove vrste su vrlo rijetke, stoga se neuspjeh trenutnih mjera upravljanja također može pripisati oskudnom znanju o biologiji ove vrste u navedenom području. Rezultati ovog istraživanja pridonose rješavanju nekoliko postojećih nedostataka i mogu biti korisni za poboljšanje mjera upravljanja koje su trenutno na snazi. Uzorci su prikupljeni pomoću vrše (košare; pletene stupice) u razdoblju od ožujka 2006. do ožujka 2008. godine tijekom mjesečnih istraživanja u središnjem Jadranu. Ukupno su uhvaćena 383 mužjaka (raspon veličina 7-29 mm SH) i 504 ženke (raspon veličina 15 - 32 mm, SH- visina školjke-puža). Srednja visina puža (± SD - značajna razlika) mužjaka iznosila je 15,84 ± 3,57 mm, a srednja visina kućice ženki je iznosila 25.31 ± 3.06 mm. Otkrivena je značajna razlika biometrijskih karakteristika između dva spola. Indeks stanja (CI) pokazao je slične sezonske trendove za oba spola, s padom od kraja zime do proljeća, nakon čega slijedi porast od ljeta do jeseni odnosno početkom zime. Najmanje vrijednosti zabilježene su u ljeto, a maksimalne zimi, što predstavlja suprotni trend u odnosu na temperaturu vode. Kod mužjaka je ovaj trend uočen počevši od kategorije visine kućice veće od 11 mm, pa bi stoga ove veličine mogle biti vrlo blizu veličini puža kod prve spolne zrelosti. Hipotetski veličina ženki kod prve spolne zrelosti (visina kućice 16-20 mm) se slaže s veličinom minimalnog ulova (MLS) trenutno uspostavljenog za ovu vrstu morskog puža (visina kućice 20 mm). Odsutnost malih ženki (visina kućice <15 mm) i velikih mužjaka (visina kućice > 23 mm) dovodi do pretpostavke da se preokret kod muškog i ženskog spola odvija kada kućica dosegne visinu od oko 20 mm. Na temelju toga, mjera upravljanja bi trebala dovesti do selektivnog zadržavanja ženki, a time i do spolnog razdvajanja s mogućim posljedicama na biologiju vrste i održivost stocka. Vrhunac indeksa stanja uočenog kod mužjaka i ženki je potvrdio da se mriještenje ovog mekušca javlja krajem zime - početkom proljeća, u skladu s obilnom prisutnošću kapsula jajašaca pričvršćenih na potopljene supstrate u tom razdoblju. Prema tome, s gledišta gospodarskog upravljanja, bilo bi poželjno da se skrati ribolovna sezona koja se u ovom trenutku proteže od jeseni do kasnog proljeća

Filling Gaps in Trawl Surveys at Sea through Spatiotemporal and Environmental Modelling

International scientific fishery survey programmes systematically collect samples of target stocks’ biomass and abundance and use them as the basis to estimate stock status in the framework of stock assessment models. The research surveys can also inform decision makers about Essential Fish Habitat conservation and help define harvest control rules based on direct observation of biomass at the sea. However, missed survey locations over the survey years are common in long-term programme data. Currently, modelling approaches to filling gaps in spatiotemporal survey data range from quickly applicable solutions to complex modelling. Most models require setting prior statistical assumptions on spatial distributions, assuming short-term temporal dependency between the data, and scarcely considering the environmental aspects that might have influenced stock presence in the missed locations. This paper proposes a statistical and machine learning based model to fill spatiotemporal gaps in survey data and produce robust estimates for stock assessment experts, decision makers, and regional fisheries management organizations. We apply our model to the SoleMon survey data in North-Central Adriatic Sea (Mediterranean Sea) for 4 stocks: Sepia officinalis, Solea solea, Squilla mantis, and Pecten jacobaeus. We reconstruct the biomass-index (i.e., biomass over the swept area) of 10 locations missed in 2020 (out of the 67 planned) because of several factors, including COVID-19 pandemic related restrictions. We evaluate model performance on 2019 data with respect to an alternative index that assumes biomass proportion consistency over time. Our model’s novelty is that it combines three complementary components. A spatial component estimates stock biomass-index in the missed locations in one year, given the surveyed location’s biomass-index distribution in the same year. A temporal component forecasts, for each missed survey location, biomass-index given the data history of that haul. An environmental component estimates a biomass-index weighting factor based on the environmental suitability of the haul area to species presence. Combining these components allows understanding the interplay between environmental-change drivers, stock presence, and fisheries. Our model formulation is general enough to be applied to other survey data with lower spatial homogeneity and more temporal gaps than the SoleMon dataset

Using AIS to Attempt a Quantitative Evaluation of Unobserved Trawling Activity in the Mediterranean Sea

In the past decades, the Automatic Identification System (AIS) has been employed in numerous research fields as a valuable tool for, among other things, Maritime Domain Awareness and Maritime Spatial Planning. In contrast, its use in fisheries management is hampered by coverage and transmission gaps. Transmission gaps may be due to technical limitations (e.g., weak signal or interference with other signals) or to deliberate switching off of the system, to conceal fishing activities. In either case such gaps may result in underestimating fishing effort and pressure. This study was undertaken to map and analyze bottom trawler transmission gaps in terms of duration and distance from the harbor with a view to quantifying unobserved fishing and its effects on overall trawling pressure. Here we present the first map of bottom trawler AIS transmission gaps in the Mediterranean Sea and a revised estimate of fishing effort if some gaps are considered as actual fishing