The relative frequency response, as derived from individually separated targets on cod, saithe and Norway pout

The relative frequency response is an important acoustic feature used to characterise acoustic targets. This response has been defined as the sv, volume backscattering coefficient, for a specific frequency relative to that of a reference frequency (38 kHz). The acoustic data commonly used in these calculations are derived from integrated measurements in a region containing multiple targets. In this study the relative frequency responses at 18, 38, 70, 120, and 200 kHz have additionally been measured using filtered target strength data on all frequencies. The spatial comparability of the sv-data is thus avoided, while the single-target detection becomes a new challenge. Target strength was extracted from in situ measurements, using calibrated and digitised data from a Simrad EK60 with split-beam transducers transmitting simultaneously at all five frequencies. Selected series with nearly pure catches of Atlantic cod (Gadus Morhua L.), saithe (Pollachius virens L.) and Norway pout (Trisopterus esmarkii L.) were analysed. The frequency response derived by the new method is compared with standard integration method

In situ calibration of observatory broadband echosounders

Today, numerous scientific echosounders are used as continuously monitoring systems in ocean observatories. These echosounders are usually calibrated in shallow water, either in laboratory tanks or at random ocean docks before deployments. If the systems are used for quantitative measurements by the observatories, they should be calibrated at the operating depths to consider the environmental effects on the calibration parameters. In this article, a simple in situ calibration method is presented, which was recently applied to one of the nodes of the Norwegian Lofoten-Vesterålen ocean observatory, when the research vessel with dynamic positioning system suspended and moved the calibration sphere between the vessel and the transducer. The calibration results of a 70-kHz split-beam echosounder demonstrate that this method can be applied to the cabled observatories.publishedVersio

Antarctic krill (Euphausia superba) catch weight estimated with a trawl-mounted echosounder during fishing

Reporting reliable catch weight estimates is important for all fisheries management. This study explores the potential for precise and direct estimation of catch weight (green weight) for the Antarctic krill (Euphausia superba) fishery by employing a high frequency acoustic sensor in the trawl. Trials were performed off the coast of the South Orkney Islands during February 2020 using a scientific macroplankton trawl and echosounder providing a 18° beam pointing downwards across the fishing circle at the trawl mouth. The acoustically estimated catch weight and the observed catch weight had a linear relationship (R2 = 0.87, F(1,10) = 69.6, p < 0.000) where the acoustically estimated catch weight significantly predicted actual catch weight (β = 1.20, p = 0.000). The acoustic vertical densities of krill increased toward the center of the trawl opening suggesting that krill were herded during fishing. The current study demonstrates that acoustically based catch weight monitoring has the potential to be used for reporting total krill catch weight in each trawl, potentially in real-time, and that similar methods could also be employed in similar types of trawl fisheries.publishedVersio

"This is who I am": Identity expressiveness and the theory of planned behavior

- Peer reviewedThis paper explores the role of self-identity expressiveness and social identity expressiveness in the context of Multimedia Messaging (MMS) adoption. An extended version of the Theory of Planned Behavior (TPB) including a wider array of identity and social influences is developed and tested. As hypothesized, self-identity expressiveness and social identity expressiveness prove to be significant determinants of intentions to use. Moreover, the extended TPB model explains 62% of the variance in usage intentions. The paper also investigates the relationship between self identity expressiveness and attitude and between social identity expressiveness and subjective norm. The study results indicate that the concept of subjective norm alone is insufficient to capture the rich universe of identity and social influences driving behavioral intentions. Implications for marketing managers and scholars are discussed. (c) 2007 Wiley Periodicals, Inc.This paper explores the role of self-identity expressiveness and social identity expressiveness in the context of Multimedia Messaging (MMS) adoption. An extended version of the Theory of Planned Behavior (TPB) including a wider array of identity and social influences is developed and tested. As hypothesized, self-identity expressiveness and social identity expressiveness prove to be significant determinants of intentions to use. Moreover, the extended TPB model explains 62% of the variance in usage intentions. The paper also investigates the relationship between self identity expressiveness and attitude and between social identity expressiveness and subjective norm. The study results indicate that the concept of subjective norm alone is insufficient to capture the rich universe of identity and social influences driving behavioral intentions. Implications for marketing managers and scholars are discussed. (c) 2007 Wiley Periodicals, Inc

Intentions to use mobile services: Antecedents and cross-service comparisons

-This article develops and tests a model to explain consumers' intention to use mobile services. Through triangulating theories from the diverse fields of information systems research, uses and gratification research, and domestication research, the authors put forth an integrated model that explains intention to use mobile services. The model proposes four overall influences on usage intention: motivational influences, attitudinal influences, normative pressure, and perceived control. The authors study the type of interactivity and process characteristics associated with the service that moderate the effects on the relationship between the proposed antecedents and usage intention. The results from empirical studies of four mobile services show strong support for the effects of motivational influences, attitudinal influences, normative pressure, and perceived control on consumers' intentions to use mobile services. Some of the effects are moderated by process characteristics (goal-directed vs. experiential services) that are associated with the service.This article develops and tests a model to explain consumers' intention to use mobile services. Through triangulating theories from the diverse fields of information systems research, uses and gratification research, and domestication research, the authors put forth an integrated model that explains intention to use mobile services. The model proposes four overall influences on usage intention: motivational influences, attitudinal influences, normative pressure, and perceived control. The authors study the type of interactivity and process characteristics associated with the service that moderate the effects on the relationship between the proposed antecedents and usage intention. The results from empirical studies of four mobile services show strong support for the effects of motivational influences, attitudinal influences, normative pressure, and perceived control on consumers' intentions to use mobile services. Some of the effects are moderated by process characteristics (goal-directed vs. experiential services) that are associated with the service

Categorizing networked services The role of intrinsic-, user network- and complement network attributes

- Peer reviewedOriginality/value - The paper contributes with a conceptual framework for understanding and categorizing both extrinsic and intrinsic drivers of service value. It extends and integrates previous work on network effects and adoption research and also offers empirical insight into an under-researched topic.Originality/value - The paper contributes with a conceptual framework for understanding and categorizing both extrinsic and intrinsic drivers of service value. It extends and integrates previous work on network effects and adoption research and also offers empirical insight into an under-researched topic

CRIMAC - Annual Report 2020

publishedVersio