1,158 research outputs found
Environmental and fishing effects on the dynamic of brown tiger prawn (Penaeus esculentus) in Moreton Bay (Australia)
This analysis of the variations of brown tiger prawn (Penaeus esculentus)
catch in the Moreton Bay multispecies trawl fishery estimated catchability
using a delay difference model. It integrated several factors responsible for
variations in catchability: targeting of fishing effort, increasing fishing
power and changing availability. An analysis of covariance was used to define
fishing events targeted at brown tiger prawns. A general linear model estimated
inter-annual variations of fishing power. Temperature induced changes in prawn
behaviour played an important role in the dynamic of this fishery. Maximum
likelihood estimates of targeted catchability (
boat-days) were twice as large as non-targeted catchability ( boat-days). The causes of recent decline in fishing
effort in this fishery were discussed.Comment: revised manuscript following reviewers comments + adding data and
code for reader
A kinematic numerical camera model for the SPOT-1 sensor
A novel method for modelling linear push-broom sensors has been developed. A numerical model which incorporates the satellite attitude and position data is used to compute the absolute orientation. This method makes a break with traditional photogrammetric practice, in that instead of using an approach based on collinearity equations, the absolute orientation is computed iteratively using a numerical multi-variable minimisation scheme. All current implementations of the model use the Powell direction-set method, but in principle, any multivariable minimisation scheme could be substituted. The numerical method has significant advantages over the collinearity approach. The number of ground control points needed to form an accurate model is reduced and the numerical approach offers a superior basis for the development of general purpose multi sensor modelling software. In order to test these assertions, a numerical model of the SPOT-1 sensor was coded and tested against a pre-existing collinearity based model. Exhaustive tests showed the numerical model, using 3 or fewer ground control points, consistendy equaled or bettered the performance of the earlier model, using between 6 and 15 ground control points, on the same test data. A general purpose sensor modelling system was developed using the code developed for the initial SPOT-1 model. Currently this system supports many rigid linear sensors systems including SPOT-1, SPOT-2, FTIR, MISR, MEOSS and ASAS. Further extensions to the system to enable it to model non-rigid linear sensors such as AVHRR and ATM are planned. Work to enable the system to perform relative orientations for a variety of sensor types is also ongoing
Improved self-gain in deep submicrometer strained silicon-germanium pMOSFETs with HfSiOx/TiSiN gate stacks
The self-gain of surface channel compressively strained SiGe pMOSFETs with HfSiOx/TiSiN gate stacks is investigated for a range of gate lengths down to 55 nm. There is 125% and 700% enhancement in the self-gain of SiGe pMOSFETs compared with the Si control at 100 nm and 55 nm lithographic gate lengths, respectively. This improvement in the self-gain of the SiGe devices is due to 80% hole mobility enhancement compared with the Si control and improved electrostatic integrity in the SiGe devices due to less boron diffusion into the channel. At 55 nm gate length, the SiGe pMOSFETs show 50% less drain induced barrier lowering compared with the Si control devices. Electrical measurements show that the SiGe devices have larger effective channel lengths. It is shown that the enhancement in the self-gain of the SiGe devices compared with the Si control increases as the gate length is reduced thereby making SiGe pMOSFETs with HfSiOx/TiSiN gate stacks an excellent candidate for analog/mixed-signal applications
Measuring Productivity Change and Efficiency on Irish Farms.
End of Project ReportThis report investigates technical change and levels of technical efficiency on Irish farms
using National Farm Survey (N.F.S.) data. It also examines whether levels of technical
efficiency are influenced by contact with the extension service.
The study utilises a stochastic production frontier approach to measure productivity growth
and the technical efficiency of a panel of Irish farms over the period 1984 to 1998. This
sample was used to calculate (a) technical change over time as measured by best practice
farms and (b) technical efficiency levels of all farms over this period. It, therefore, provides
disaggregated estimates of technical change by farming system as well as quantifying the
average level of technical efficiency. The project also examines the factors associated with
differences in technical efficiency between farms and the impact of extension service contact
on farm-level technical efficiency.
Mean technical change (i.e. changes in best practice) continued, albeit at a declining rate,
throughout the period studied. Significant differences were revealed in the rate of technical
change on farms of different types. For example technical change on dairy and crop farms
averaged nearly 2 per cent per annum while technical regress occurred on beef and sheep
farms.
In addition to examining technical change, farm efficiency relative to best practice within
each farming system was also measured. Results indicate that farms achieved, on average,
approximately 65 per cent of the efficiency level of best practice farms. The average level of
farm efficiency has been decreasing by 0.4 per cent per annum indicating that the gap
between best practice farms and all farms has been increasing by this amount over time.
Thirty one percent of the most efficient farms were dairy farms while 23 per cent were arable
farms. Approximately 52 per cent of the least efficient farms were cattle farms while a further
31 per cent were sheep farms. Average efficiency over the period was 34.2 per cent in the
least efficient quintile of farms. This compared to almost 90 per cent for the most efficient
quintile of farms.
A positive relationship between age and efficiency was found up to the age of 49 years after
which the relationship between age and efficiency becomes negative. The farm debt to assets
ratio was positively related to efficiency while farm size and location in the West of Ireland
was negatively related to efficiency.
Farms in contact with the extension service were found to be on average 6.5 per cent more
efficient than farms without contact. Contact farms with a lower than average dependency on
direct payments were a further 6.6 per cent than contact farms with an average dependency
on direct payments. Contact farms with a higher than average dependence on direct payments
were 1.9 per cent less efficient than the same group of contact farms. However, efficiency on
these farms with a high dependence on direct payments was still, on average, higher than on
farms with no extension contact.Teagasc Walsh Fellowshi
The impact of self-heating and SiGe strain-relaxed buffer thickness on the analog performance of strained Si nMOSFETs
The impact of the thickness of the silicon–germanium strain-relaxed buffer (SiGe SRB) on the analog performance of strained Si nMOSFETs is investigated. The negative drain conductance caused by self-heating at high power levels leads to negative self-gain which can cause anomalous circuit behavior like non-linear phase shifts. Using AC and DC measurements, it is shown that reducing the SRB thickness improves the analog design space and performance by minimizing self-heating. The range of terminal voltages that leverage positive self-gain in 0.1 μm strained Si MOSFETs fabricated on 425 nm SiGe SRBs is increased by over 100% compared with strained Si devices fabricated on conventional SiGe SRBs 4 μm thick. Strained Si nMOSFETs fabricated on thin SiGe SRBs also show 45% improvement in the self-gain compared with the Si control as well as 25% enhancement in the on-state performance compared with the strained Si nMOSFETs on the 4 μm SiGe SRB. The extracted thermal resistance is 50% lower in the strained Si device on the thin SiGe SRB corresponding to a 30% reduction in the temperature rise compared with the device fabricated on the 4 μm SiGe SRB. Comparisons between the maximum drain voltages for positive self-gain in the strained Si devices and the ITRS projections of supply-voltage scaling show that reducing the thickness of the SiGe SRB would be necessary for future technology nodes
A lexical database for public textual cyberbullying detection
Public textual cyberbullying has become one of the most prevalent issues associated with online safety of young people, particularly on social networks. To address this issue, we argue that the boundaries of what constitutes public textual cyberbullying needs to be first identified and a corresponding linguistically motivated definition needs to be advanced. Thus, we propose a definition of public textual cyberbullying that contains three necessary and sufficient elements: the personal marker, the dysphemistic element and the cyberbullying link between the previous two elements. Subsequently, we argue that one of the cornerstones in the overall process of mitigating the effects of cyberbullying is the design of a cyberbullying lexical database that specifies what linguistic and cyberbullying specific information is relevant to the detection process. In this vein, we propose a novel cyberbullying lexical database based on the definition of public textual cyberbullying. The overall architecture of our cyberbullying lexical database is determined semantically, and, in order to facilitate cyberbullying detection, the lexical entry encapsulates two new semantic dimensions that are derived from our definition: cyberbullying function and cyberbullying referential domain. In addition, the lexical entry encapsulates other semantic and syntactic information, such as sense and syntactic category, information that, not only aids the process of detection, but also allows us to expand the cyberbullying database using WordNet (Miller, 1993)
Detecting Discourse-Independent Negated Forms of Public Textual Cyberbullying
[EN] Cyberbullying is a risk associated with the online safety of young people and, in this paper, we address one of its most common implicit forms – negation-based forms. We first describe the role of negation in public textual cyberbullying interaction and identify the cyberbullying constructions that characterise these forms. We then formulate the overall detection mechanism which captures the three necessary and sufficient elements of public textual cyberbullying – the personal marker, the dysphemistic element, and the link between them. Finally, we design rules to detect both overt and covert negation-based forms, and measure their effectiveness using a development dataset, as well as a novel test dataset, across several metrics: accuracy, precision, recall, and the F1-measure. The results indicate that the rules we designed closely resemble the performance of human annotators across all measures.Power, A.; Keane, A.; Nolan, B.; O'neill, B. (2018). 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"Cyber Bullying Detection using Social and Textual Analysis." Paper presented at the 3rd International Workshop on Socially-Aware Multimedia, 3 - 6. Orlando, Florida, November 7. https://doi.org/10.1145/2661126.2661133InternetSlang. 2017. "Internet Slang - Internet Dictionary." Accessed October 19. http://www.Internetslang.com/.Kavanagh, P. 2014. "Investigation of Cyberbullying Language & Methods." MSc diss., ITB, Ireland.Kontostathis, A., Reynolds, K., Garron, A. and Edwards, L. 2013. Detecting Cyberbullying: Query Terms and Techniques. Paper presented at the 5th Annual ACM Web Science Conference. Paris, May 2-4. https://doi.org/10.1145/2464464.2464499Langos, C. 2012. "Cyberbullying: The Challenge to Define." Cyberpsychology, Behavior, and Social Networks, 15(6): 285-289. https://doi.org/10.1089/cyber.2011.0588Lawler, J. 2005. "Negation and NPIs." http://www.umich.edu/~jlawler/NPIs.pdfLivingstone, S.,Haddon, L., Görzig, A., and Ólafsson, K. 2011. 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Paper presented at the 1st conference on CAW. Madrid, April 20-24
Digital technologies in bronchiectasis physiotherapy services: A survey of patients and physiotherapists in a UK centre
Introduction We aimed to explore how digital technology is currently used, could be used and how services could be improved in order to optimise bronchiectasis physiotherapy care. Methods Online surveys were designed and distributed amongst people with bronchiectasis and physiotherapists in Northern Ireland. Responses to closed and open question formats were collected and analysed. Results The survey was completed by 48 out of 100 physiotherapists (48%) between January 2020 and January 2021 and by 205 out of 398 people with bronchiectasis (52%) between October 2020 and October 2021. 56% of physiotherapists (27 out of 48) reporting using some type of digital technology to facilitate services, whereas 44% (21 out of 48) reported that they had never used a digital technology in this patient group. When physiotherapists were asked whether they would be likely to use certain remote and/or digital options to deliver follow-up care for airway clearance techniques, most (31–38 out of 48; 65–79%) indicated that they would. Regarding patient responses, most reported that they would use telephone consultation (145 out of 199, 73%) and a smaller proportion were likely to use video consultation (64 out of 199, 32%). The most commonly mentioned theme for improvement amongst patients was follow-ups, while improved access, quality of services and treatments were the most commonly mentioned amongst physiotherapists. Conclusion Despite a large proportion of physiotherapists in this survey reporting no current use of digital technology in bronchiectasis physiotherapy care, there was significant interest and willingness to do so, amongst both physiotherapists and patients. This survey highlighted a range of care areas, specifically follow-up visits, where digital methods could be further explored.</p
Stock Assessment of Ballot's saucer scallop (Ylistrum balloti) in Queensland
This assessment estimates the status of saucer scallops in the main fishing grounds of the Queensland Southern Inshore fishery. The stock assessment data inputs included total harvests, standardised catch rates and fishery independent density estimates.
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Analyses suggested that spawning biomass in 2019 fell to around 17 per cent of the unfished level. The report presents recommendations on fishing effort levels to begin rebuilding the stock to levels consistent with 40 per cent of unfished biomass
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