61 research outputs found
Sequential and parallel complexity of learning DFA
It is known that the class of deterministic finite automata is polynomial
time learnable by using membership and equivalence queries. We investigate the query complexity of learning deterministic finite automata, i.e., the number of membership and equivalence queries made during the process of learning.
We prove lower bounds on the number of alternations between membership
and equivalence queries, and also show that a trade-off exists, allowing us to reduce the number of equivalence queries at the price of increasing the number of membership queries. Finally, we study learning in a parallel model, the CRCW PRAM. We prove a lower bound on the parallel time needed for learning and design an algorithm that asymptotically achieves this bound
Simulation of biomass trends of eastern bluefin tuna (thunnus thynnus) stock under current management regulations
[EN] Juvenile catches of bluefin tuna (< 30 kg) have fallen considerably due to present regulations
for the eastern stock. Considering past catches of juvenile tuna, large numbers of young tuna
now survive and may contribute to future spawning stock. We consider the possibility that these
measures are maintained for the period 2007-2020 and simulate the biomass output provided
by these tuna that have not been and will not be caught. A stochastic matrix projection model
was used. The output from the simulation suggest that by 2010, there will be about one million
more tuna of ages 1 to 7 than in 2006 with an increase of about 26,000 tons (95% CI 15.795-
35.481 tons). By 2020, the population is expected to increase by about 1.6 million of individuals
of ages up to 17 years which will imply an increase in biomass of 109.178 tons (95% CI
98.264-118.173 tons) when compared to figures in 2006.[FR] Les prises des thons rouges juvéniles (< 30 kg) ont considérablement diminué en raison des
réglementations actuelles appliquées au stock de l’Est. Si l'on considère les prises de thonidés
juvéniles réalisées dans le passé, un grand nombre de juvéniles survivent désormais et peuvent
contribuer au futur stock de reproducteurs. Nous considérons que ces mesures sont maintenues
pendant la période allant de 2007 à 2010 et nous simulons les résultats de la biomasse de ces
thonidés qui n'ont pas été et ne seront pas capturés. Un modèle de projection de matrice
stochastique a été utilisé. Les résultats de la simulation donnent à penser qu’il y aura
approximativement un million de thonidés supplémentaires d’âges 1 à 7 d’ici à 2010 par
rapport à 2006, ce qui représente une augmentation d'environ 26.000 tonnes (95% CI 15.795 -
35.481 tonnes). D’ici à 2020, la population devrait augmenter d’environ 1,6 million de
spécimens d’âges allant jusqu’à 17 ans, ce qui impliquera une hausse de la biomasse de
109.178 t (intervalles de confiance de 95 % 98.264 – 118.173 t), si l’on compare ces chiffres
avec ceux de 2006.[ES] Las capturas de juveniles de atún rojo (< 30 kg) han descendido de forma considerable debido
a los reglamentos actuales para el stock oriental. En comparación con las capturas de juveniles
del pasado, ahora sobreviven muchos juveniles y éstos podrían contribuir al futuro stock
reproductor. En el documento se ha considerado la posibilidad de que estas medidas se
mantengan para el periodo 2007-2020, y se simularon los resultados de biomasa
proporcionados por estos atunes que no han sido ni serán capturados. Se utilizó un modelo de
proyección de matriz estocástica. Los resultados de la simulación sugieren que en 2010 habrá
en torno a un millón más de atunes de edades 1 a 7 que en 2006, con un incremento de
aproximadamente 26.000 t (CI 95% 15.795–35.481 t). Desde ahora hasta 2020, se prevé que la
población aumentará en aproximadamente 1,6 millones de ejemplares de edades hasta 17 años,
lo que implicará un aumento en la biomasa de 109.178 t (CI 95% 98.264-118.173 t) con
respecto a las cifras de 2006.Belda Perez, EJ.; Cort, JL. (2011). Simulation of biomass trends of eastern bluefin tuna (thunnus thynnus) stock under current management regulations. Collective Volume of Scientific Papers. 66(2):989-994. http://hdl.handle.net/10251/53266S98999466
Análisis comparativo entre ecuaciones predictivas del peso en función de la talla en atún rojo, Thunnus thynnus (L.). Documento de trabajo (julio, 2014)
Se comparan los modelos talla-peso tradicionalmente utilizados en la evaluación del atún rojo, Thunnus thynnus (L.), en el seno del comité científico de la ICCAT (SCRS), con otros dos recientemente adoptados por dicho comité. El resultado indica que los modelos adoptados subestiman claramente el peso real de los atunes rojos en fase reproductiva
Relationship between weight and linear dimensions of Bluefin tuna (Thunnus thynnus) following fattening on western Mediterranean farms
This study presents various models based on formulae relating weight and dimensions (length, height and width) of Bluefin tuna, Thunnus thynnus (L.), fattened in captivity. The main aim of establishing these expressions is to design tools for indirectly predicting the weight of a Bluefin tuna from measurements of one or more dimensions obtained using non- invasive methods such as stereoscopic cameras. Measurements of maximum length, height and width following slaughter were taken of fish fattened in captivity (n = 2078). Different relationships drawn from the dimensions of the tuna against their weight are fitted with part of the data collection and later checked against a reserved sample set. The resulting formu- lae are compared with the formulae most commonly used in the case of wild tuna. The results of this study confirm that, for tuna fattened in cages, the availability of more than one dimension to estimate weight improves the predictive power of the model and reduces error in the estimate.En prensa4,41
Effects of offshore wind farms operational noise on bluefin tuna behaviour
The number of offshore wind farms is growing up quickly in the lasts years. Several studies about its environmental acoustic impacts have been developed at the same time the industry expands, most of them related to the high level impulsive noise produced during the pile diving process associated to the construction stage. Nevertheless, the study of the impact of the operational noise of turbines is very limited. In this paper we investigate the behavioural response of Bluefin tuna when exposed to the operation noise of a turbine. We analysed tuna reaction in terms of three parameters: depth of the school, swimming pattern and changes in the swimming direction. The experiment was developedin a fixed commercial tuna cage in the Mediterranean Sea. The usual behaviour of Bluefin tuna in captivity conditions was previously analysed using a continuous monitorization. Variations in depth were observed when feeding boat approaches, which could be interpreted as a consequence of the acoustical stimulus. The turbine noise was acoustically characterized, and reproduced using a broad-band underwater source. To monitor tuna behaviour two echosounders and a video system were simultaneously used. When exposed to short duration noise tuna behaviour does not exhibit clear disturbances. Nevertheless, with long duration emission tuna reacted: school reduced the radio of thecircular swimming region, moved up to the surface and some individuals were disorientated. Tuna seems to be habituated after several repetitions is short time.Proyecto AZIMUT. This work was financially support from Spanish Government by grant AP2009-4459. We thank both personal and material facilities provided by Grup Balfegó and Nuevo Tomás y Carmen crew
Bluefin tuna (Thunnus thynnus) tagging survey in the Bay of Biscay in summer 2005
A brief summary of the conventional tagging survey carried out during the summer fishing
season in 2005 in the Bay of Biscay is presented. A total of 1696 juveniles of bluefin tuna have
been tagged, corresponding to group ages 1 and 2. Two different conventional tags have been
used. Fifty-one recaptures have been recovered up to date.Le présent document fournit un résumé de la campagne de marquage conventionnel de thon
rouge menée au cours de l’été 2005 dans le Golfe de Gascogne. Au total, 1.696 juvéniles de thon
rouge ont été marqués, correspondant aux groupes d’âge 1 et 2. Deux types distincts de
marques conventionnelles ont été utilisés. Cinquante-et-une marques ont été récupérées à ce
jour.Se presenta un resumen de la campaña de marcado convencional de atún rojo llevada a cabo
durante el verano del 2005 en el Golfo de Vizcaya. En total se han marcado 1696 ejemplares de
1 y 2 años de edad. Se han utilizado dos modelos distintos de marcas convencionales. Hasta la
fecha se han recapturado cincuenta y un ejemplares
Tracking bluefin tuna cohorts from east Atlantic Spanish fisheries since the 1980s
Relative abundance and mean size at age analyses were performed for the catches of three Atlantic
Spanish fisheries, in search of an exceptionally abundant cohort in the recent history of the eastern
Atlantic and Mediterranean bluefin tuna stock. Length distributions of baitboat fisheries, both in the Bay
of Biscay and areas close to the Strait of Gibraltar as well as trap catches from the Spanish Atlantic
coast were converted to age distributions using age length keys from calcified structures. Results do
validate indirectly the ageing method. The 1994 cohort was clearly tracked for juveniles and young
adults, 3 to 7 years old, in baitboat catches, and also for older specimens, 9 to 11 years old, in the trap
fisheries. Based on these results, it is suggested that the juvenile and young adults fisheries in the
western part of the Iberian Peninsula are interconnected between one another and with the Balearic
Islands area of the western Mediterranean, as it is the nearest spawning ground described and because
it is also supported by tagging and other studies.Afin de trouver une cohorte exceptionnellement abondante dans la récente histoire du stock de ton
rouge de l’Atlantique Est et de la Méditerranée, on a procédé à une analyse de l’abondance relative et
de la taille moyenne par âge des captures réalisées par trois pêcheries espagnoles de l’Atlantique. Les
distributions par tailles de deux pêcheries de canneurs dans le Golfe de Gascogne et dans les eaux
proches du Détroit de Gibraltar, ainsi que les prises des madragues de la côte atlantique espagnole, ont
été converties en âges à l’aide des clefs taille-âge obtenues à partir de la lecture de structures
calcifiées. Les résultats valident indirectement la méthode de détermination de l’âge. La cohorte de
1994 affiche une forte indication présente chez les juvéniles et les jeunes adultes, de 3 à 7 ans, capturés
dans les pêcheries de canneurs ainsi que chez les spécimens d’âge plus avancé, de 9 à 11 ans, pêchés à
la madrague. Ces résultats suggèrent que les pêcheries de juvéniles et de jeunes adultes de la partie
occidentale de la péninsule ibérique sont interconnectées entre elles ainsi qu’avec la zone des îles
Baléares, en Méditerranée occidentale, étant donné qu’il s’agit de la zone de frai la plus proche et qu’il
existe des indices de cette relation d’après les études de marquage et d’autres études.Para encontrar una cohorte excepcionalmente abundante en la historia reciente del stock de atún rojo
del Atlántico este y Mediterráneo, se realizó un análisis de la abundancia relativa y la talla media por
edad de las capturas de tres pesquerías atlánticas españolas. Las distribuciones de tallas de dos
pesquerías de cebo vivo, en el Golfo de Vizcaya y en aguas próximas al Estrecho de Gibraltar, así como
las capturas de las almadrabas de la costa atlántica española, fueron convertidas a edades mediante el
uso de claves talla edad, obtenidas a partir de la lectura de piezas esqueléticas. Los resultados validan
indirectamente el método de determinación de la edad. La cohorte de 1994 presenta una fuerte señal
que pudo ser encontrada en los juveniles y adultos jóvenes, 3 a 7 años, capturados en las pesquerías de
cebo vivo y también en especimenes mayores, 9 a 11 años, pescados con las almadrabas. Con esto
resultados se sugiere que las pesquerías de juveniles y adultos jóvenes de la parte occidental de la
península Ibérica están interconectadas entre ellas y con el área de las Islas Baleares, en el
Mediterráneo occidental, puesto que es la zona de puesta más próxima y porque también hay evidencias
de esta relación mediante el marcado y otros estudios
Monitoring of Caged Bluefin Tuna Reactions to Ship and Offshore Wind Farm Operational Noises
Abstract: Underwater noise has been identified as a relevant pollution affecting marine ecosystems in different ways. Despite the numerous studies performed over the last few decades regarding the adverse effect of underwater noise on marine life, a lack of knowledge and methodological procedures still exists, and results are often tentative or qualitative. A monitoring methodology for the behavioral response of bluefin tuna (Thunnus thynnus) when exposed to ship and wind turbine operational noises was implemented and tested in a fixed commercial tuna feeding cage in the Mediterranean sea. Fish behavior was continuously monitored, combining synchronized echosounder and video recording systems. Automatic information extracted from acoustical echograms was used to describe tuna reaction to noise in terms of average depth and vertical dimensions of the school and the indicators of swimming speed and tilt direction. Video recordings allowed us to detect changes in swimming patterns. Different kinds of stimuli were considered during bluefin tuna cage monitoring, such as noise generated by feeding boats, wind farm operational noise, and other synthetic signals projected in the medium using a broadband underwater projector. The monitoring system design was revealed as a successful methodological approach to record and quantify reactions to noise. The obtained results suggested that the observed reactions presented a strong relationship with insonification pressure level and time. Behavioral changes associated with noise are difficult to observe, especially in semi-free conditions; thus, the presented approach offered the opportunity to link anthropogenic activity with possible effects on a given marine species, suggesting the possibility of achieving a more realistic framework to assess the impacts of underwater noise on marine animals.Versión del edito
Report of the 2006 ICCAT workshop for bluefin tuna direct ageing
This report provides the presentations, discussions and conclusions from the ICCAT bluefin
tuna workshop for direct ageing held in Santander, Spain, in April 2006. The report
summarizes the ageing criteria used in the past and the agreements on future age determination
based on otoliths, vertebrae and spines. Advantages and disadvantages of each calcified
structure for ageing and border interpretation were discussed. It was considered that bluefin
tuna age interpretation becomes very difficult from age ten onwards using the whole vertebra
and the spine sections methods, but this last technique continues to be useful for older ages.
Otolith sections can be used for the whole age range. Participants agreed that none of these
three structures could be excluded from routine ageing because otoliths are not easily
available. Age estimations within the same structure and between different structures of the
same specimen were compared for several readers. Better precision was found between spine
readers compared to vertebra and otolith readers. Good age agreement was also achieved
between readers of spines and vertebrae from the same bluefin for ages less than 12 years.
Preliminary results from radiocarbon assays on otoliths were presented at the workshop and
gave promising outcomes for bluefin tuna age validation. Also, these suggested that bluefin
tuna can live longer than had previously been established and that a review is needed of the
currently used asymptotic size and growth rate for both stocks. Another important contribution
of the workshop was a manual for age interpretation.Le présent rapport recueille les présentations, discussions et conclusions de l’Atelier de
l’ICCAT chargé de la détermination directe de l’âge du thon rouge, tenu à Santander
(Espagne) au mois d’avril 2006. Le rapport résume les critères employés par le passé pour
interpréter l’âge et les accords pour la détermination future de l’âge à partir des otolithes,
vertèbres et épines. L’Atelier a discuté des avantages et des inconvénients de chaque structure
calcifiée pour déterminer l’âge et l’interprétation du type de bord. On a abordé la difficulté de
l’interprétation de l’âge des thons de plus de 10 ans au moyen de la vertèbre entière et des
sections des épines, bien que cette dernière méthode continue d’être utile pour les âges
avancés. Les sections d’otolithes peuvent être employées pour toute la gamme d’âges. Les
participants ont convenu qu’aucune de ces trois structures ne doit être exclue pour
l’interprétation de l’âge parce qu’il n’est pas toujours possible d’obtenir des otolithes. On a
comparé les lectures de l’âge à l’intérieur de la même structure et entre différentes structures
du même exemplaire pour divers lecteurs. On a obtenu une plus grande précision parmi les
lecteurs d’épines que parmi les lecteurs de vertèbres et d’otolithes. On a également obtenu un
bon accord entre les lecteurs d’épines et de vertèbres originaires du même exemplaire pour les
âges inférieurs à 12 ans. Les résultats préliminaires des essais de radiocarbone dans les
otolithes ont été présentés à l’Atelier, offrant de bonnes perspectives pour son utilisation dans la validation de l’âge. Ces résultats indiquent aussi que le thon rouge a une plus grande
longévité que ce qui avait été auparavant établi et qu’il est nécessaire de réviser la longueur
asymptotique et le taux de croissance actuellement utilisés. L’élaboration d’un manuel aux fins
de l’interprétation de l’âge a constitué une autre contribution importante de l’Atelier.Este informe recoge las presentaciones, discusiones y conclusiones del congreso de ICCAT
para la determinación directa de la edad de atún rojo, celebrado en Santander, España, en
abril de 2006. El informe resume los criterios empleados en el pasado para interpretar la edad
y los acuerdos para la determinación futura de la edad a partir de otolitos, vértebras y espinas.
Se discutieron las ventajas y los inconvenientes de cada estructura calcificada para determinar
la edad y la interpretación del tipo borde. Se planteó la dificultad en la interpretación de la
edad de atunes mayores de 10 años utilizando la vértebra entera y las secciones de espinas, no
obstante este último método continúa siendo útil para edades mayores. Las secciones de
otolitos pueden ser empleadas para todo el rango de edades. Los participantes acordaron que
ninguna de estas tres estructuras deben excluirse para la interpretación de la edad porque no
siempre es posible obtener los otolitos. Se compararon las lecturas de edad dentro de la misma
estructura y entre diferentes estructuras del mismo ejemplar para varios lectores. Se obtuvo
una mayor precisión entre lectores de espinas comparada con las obtenidas por los lectores de
vértebras y otolitos. También se obtuvo un buen acuerdo entre lectores de espinas y vértebras
procedentes del mismo ejemplar para edades menores de 12 años. Los resultados preliminares
de las pruebas de radiocarbono en otolitos fueron presentados en el congreso, proporcionando
buenas expectativas para su uso en la validación de la edad. Estos resultados también indican
que el atún rojo es más longevo de lo que se consideraba y que es necesaria una revisión de la
longitud asintótica y de la tasa de crecimiento empleadas actualmente. Otra importante
contribución del congreso fue la elaboración de un manual para la interpretación de la edad
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