Forschung und Entwicklung in der Aquakultur: Ein Überblick über Arbeitsgebiete und offene Fragen

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Forschung und Entwicklung in der Aquakultur: Ein Überblick über Arbeitsgebiete und offene Fragen

Dieses Working-Paper konzentriert sich auf die Aquakultur als Produktionssystem für Fische in Hocheinkommensländern. Die Produktion von Mollusken, Crustaceen und Pflanzen wird nicht betrachtet. Die Aquakulturproduktion in Entwicklungsländern, in denen es teilweise an Vorschriften für Hygienemaßnahmen, Lebensmittelsicherheit und Umweltstandards mangelt, die bspw. den Einsatz von Chemikalien regeln, wird ebenfalls nicht in diesem Working Paper behandelt. Unterschiede zwischen der Produktion in Europa und China bestehen auch im Arbeits- und Kapitaleinsatz, der sich zum Teil durch die Nutzung von intensiven Systemen begründen lässt. Dieses Working Paper soll einen Einblick in die wesentlichen Bereiche der Aquakulturforschung- und Entwicklung (AQ-F+E) bieten. In der Vergangenheit basierten viele Forschungserfolge in der Aquakultur eher auf „trial and error" als auf wissenschaftlicher Bedeutung der Aquakultur (2008-12-23) Forschung (Shang 1986). Im Vergleich zu der Nutztierhaltung, wie von Schweinen, Rindern und Geflügel, ist die Aquakultur eine ,junge" Technologie in der noch viel Forschungs- und Entwicklungsbedarf und somit auch viele Chancen bestehen. Das Working Paper dient als Vorstufe einer weltweiten Delphi-Umfrage unter Aquakulturex-perten. In der Delphi-Studie bewerten die Experten in mehreren Runden die derzeitige und zukünftige Relevanz zu den in diesem Working Paper beschriebenen AQ-F+E-Bereichen sowie ausgewählte Fragestellungen zu den einzelnen Themenbereichen. In einem weiteren Schritt sollen dann die Ergebnisse der Delphi-Studie in Kombination mit einer Fischmarktanalyse dazu dienen, die wohlfahrtsökonomischen Auswirkungen der AQ-F+E abzuschätzen. Das Working Paper ist wie folgt gegliedert: Um zunächst einen Überblick über die Bedeutung der Aquakultur zu erlangen dient Kapitel 2. Anschließend werden unterschiedliche Forschungsbereiche der Aquakultur vorgestellt. Dies sind die Bereiche Züchtung und Reproduktion (Kap. 2), Haltungs- und Wassermanagement (Kap. 3), Fischgesundheit (Kap. 4) und Fischernährung (Kap. 5). Zusätzlich soll die Forschung im Bereich des Marketings, Qualitätsmanagements und der Ökonomie der Aquakultur (Kap. 6) beleuchtet werden, bevor das Working Paper mit einer Zusammenfassung und einer Schlussbetrachtung (Kap. 7) endet.This working paper focuses on aquaculture as a production system for fish in high-income countries. Production of mollusks, crustaceans and plants is not considered. Aquaculture production in developing countries, where there is sometimes a lack of regulations for hygiene measures, food safety and environmental standards that regulate, for example, the use of chemicals, is also not covered in this Working Paper. Differences between production in Europe and China also exist in labor and capital inputs, which can be partly justified by the use of intensive systems. This Working Paper is intended to provide insight into the major areas of aquaculture research and development (AQ-F+E). In the past, many research successes in aquaculture were based on "trial and error" rather than scientific significance of aquaculture (2008-12-23) research (Shang 1986). Compared to livestock production, such as pigs, cattle and poultry, aquaculture is a 'young' technology in which there is still much need for research and development, and thus many opportunities. The Working Paper serves as a preliminary stage of a worldwide Delphi survey among aquaculture experts. In the Delphi study, the experts will evaluate in several rounds the current and future relevance to the AQ F+E areas described in this Working Paper as well as selected questions on the individual topics. In a further step, the results of the Delphi study in combination with a fish market analysis will then be used to estimate the welfare economic impact of AQ-F+E. The working paper is organized as follows: To first get an overview of the importance of aquaculture serves chapter 2. Then different research areas of aquaculture are presented. These are the areas of breeding and reproduction (chapter 2), husbandry and water management (chapter 3), fish health (chapter 4) and fish nutrition (chapter 5). In addition, research in marketing, quality management and economics of aquaculture (chap. 6) will be highlighted before the working paper ends with a summary and concluding remarks (chap. 7)

Theoretische Konzepte der Zeitreihenanalyse und Anwendungen auf die Signalklassifikation in technischen Systemen.

Gegenstand dieser Arbeit ist die Entwicklung und Anwendung einiger Konzepte der Zeitreihenanalyse auf technische Problemstellungen. Unser Interesse an technischen Systemen entsteht aus der Idee, Anwendungsmöglichkeiten der nichtlinearen Zeitreihenanalyse auf realistische Probleme von "mittlerer Komplexität" zu untersuchen, d.h. auf Fragestellungen bei realen Systemen, die nur eine begrenzte Anzahl (effektiver) Freiheitsgrade und eine begrenzte Nichtstationarität aufweisen. Zwei Probleme werden hier betrachtet: Die Fehlerfrüherkennung bei Induktionsmotoren durch Überwachung des Statorstroms und die automatische Qualitätskontrolle von elektrischen Schiebedächern durch Klassifikation von Körperschallsignalen. Der erste Teil dieser Arbeit ist theoretisch und enthält einige Grundlagen und Konzepte für den mehr angewandten zweiten Teil. Wir geben zunächst einen Überblick über lineare und quadratische Zeit-Frequenz Darstellungen, welche sich als geeigneter Ausgangspunkt für beide untersuchten Probleme erweisen. Hierbei sind im Hinblick auf die Signalanalyse die Eigenschaften von gefensterten Fourier- und Wavelettransformationen, insbesondere die Zeit-Frequenz Auflösungscharakteristik dieser Abbildungen von Interesse. Da in allen Anwendungen nur endliche, diskret abgetastete Zeitreihen zur Verfügung stehen, wird anschließend der genaue Zusammenhang zwischen der diskreten und kontinuierlichen Version dieser Transformationen diskutiert, wofür das Shannonsche Samplingtheorem den Verknüpfungspunkt bildet. Für die Klassifikation von experimentellen Daten anhand extrahierter Merkmale werden schließlich Schätzer für den Bayeschen Fehler, d.h. den minimalen Fehler, der in einer Klassifikationsstatistik erzielt werden kann, eingeführt.Wir stellen eine neue Methode zur Fehlerfrüherkennung bei Induktionsmotoren vor, wozu das Konzept der geometrischen Signaltrennung im Merkmalsraum eingeführt wird: Während einer Trainingsperiode werden Teilstücke der Zeitreihe von einer Phase des Statorstroms in Merkmalsvektoren in einem Merkmalsraum transformiert. Nach Definition einer lokalen Metrik im Merkmalsraum können Merkmalsvektoren, die während des Betriebs "on-line" berechnet werden, mit den Trainingsvektoren verglichen werden, welche die erlaubten Betriebszustände des Motors repräsentieren. Falls im Merkmalsraum keine Nachbarn der Testvektoren in der Trainingsdatenbasis existieren, ist der zugehörige Betriebszustand unbekannt und wird als fehlerhaft angenommen, falls er über eine gewisse Zeitdauer besteht. Wechselnde Umwelteinflüsse stellen hierbei das Hauptproblem dar, wofür die geometrische Methode eine Lösung bietet: Durch Kombination der Informationen aus zwei Merkmalsräumen können die Umweltbedingungen während des Betriebs teilweise herausgerechnet werden; diese Korrektur erlaubt die statistisch signifikante Trennung von unbekannten Umwelteinflüssen und Fehlern.Wir führen als nächstes einen Merkmalsvektor zur automatischen akustischen Qualitätskontrolle ein. Hierzu wird das Schließgeräusch von elektrischen Schiebedächern aufgenommen. Wir suchen nicht explizit nach den Merkmalen der Zeitreihen, welche gute und fehlerhafte Produkte unterscheiden, sondern nutzen die Eigenschaft aus, daß die Informationen zur Fehlererkennung vom menschlichen Gehör, d.h. von Experten, aufgelöst werden können. Wir approximieren die Zeit-Frequenz Auflösungscharakteristik des menschlichen Gehörs durch eine Wavelettransformation und definieren eine verallgemeinerte (Rest-) Klasse von Wavelettransformationen, welche es erlaubt, im Zeitraum zu mitteln, ohne die zeitaufgelösten Informationen zu verlieren. Durch diesen Mittelungsprozeß können Rauschen und statistische Fluktuationen hinreichend reduziert werden, um die für die Klassifikation der Signale relevanten Merkmale hervorzuheben. Wir studieren die Eigenschaften der Merkmalsvektoren zunächst anhand künstlicher Signale. Die folgende Anwendung auf die Schiebedachdaten bestätigt (qualitativ) diese Ergebnisse.Subject of this work is the development and application of some concepts of time series analysis to technical systems. Our interest in technical systems arises from the idea to study applications of nonlinear time series analysis to fully realistic problems of "intermediate complexity", i.e. to systems which have a limited number of (effective) degrees of freedom and limited nonstationarity. Two problems are treated here: The induction motor failure detection using stator current monitoring and the automatic quality control of sliding sunroofs by classifying structure-born sound signals. The first part of this work is theoretical and contains some background material for the more applied second part. We give an overview over linear and quadratic time-frequency representations, which turn out to be a suitable starting point for both treated problems. From the viewpoint of signal analysis we focus on the properties of windowed Fourier- and wavelet transforms, especially the time-frequency resolution characteristics. Subsequently the relation between the continuous and discrete version of these transforms are thoroughly discussed, for which Shannon's sampling theorem provides the connection. For the classification of feature vectors calculated from experimental time series we finally introduce estimators for the Bayes error, i.e. the smallest error which can be achieved in a classification statistics. We present a new method for on-line induction motor failure detection, where the concept of geometrical signal separation in feature space is introduced: A set of observations from a single phase of the stator current is transformed into feature vectors in a feature space. After establishing a local metric in the feature space close neighbours of the present vector are searched for in a data basis representing the allowed states of the motor. In their absence the present state is a novelty, which is considered as a failure if it persists for a certain time. Varying environmental conditions turn out to be the main problem during fault sensing. The geometric method offers a solution for that by combining the information of two feature spaces. This correction allows for our data the statistically significant separation of unknown environmental conditions and motor failures.We next introduce a feature vector for automatic acoustic quality control. For this purpose the sliding noise of electric sunroofs was recorded. We do not explicitely search for the features of the time series which distinguish good from defective products, but take advantage of the fact that the information being relevant for failure detection can be resolved by the human ear, i.e. by experts. We approximate the time-frequency resolution of the ear by a wavelet transform and define a generalized class of wavelet transforms, which can be averaged in the time domain without loosing the time-resolved information. By this averaging process statistical fluctuations and noise are reduced sufficiently to reveal the features of the signals for the aimed classification. We first study the properties of the feature vectors using artifical signals. The subsequent application to the sliding sunroof data confirms (qualitatively) these results.Datei d089902b.pdf = korrigierte Fassung vom 10.04.200

Studies on the market assessment of aquaculture research by a small producer country

This dissertation consists of several essays, each one dealing with a specific aspect of the estimation of induced benefits from aquaculture R&D. The first essay gives an overview of the development of capture and aquaculture production, as well as fish consumption. The second essay analyses the quality of international fish trade data. The third essay provides a network analysis of international fish trade. The fourth essay deals with the current strength and future direction of aquaculture R&D, as anticipated by aquaculture experts. The fifth essay analyses econometrically the demand for fish in Germany. The last essay, finally, presents a simulation model for estimating the potential benefits of aquaculture R&D. This simulation model makes use of many of the data and insights generated in the earlier essays. The economic evaluation of aquaculture R&D conducted in Germany provides a basis for decision making and public investments into aquaculture R&D

Fish in the city

Aquaculture is the most recent addition to animal husbandry and it is the fastest growing food production industry. Its contribution to world food security in the 21st century is already significant and it is bound to continue to grow because demand for fish for human consumption is rapidly increasing whereas fish supplies from ocean fisheries are likely to decline. The rapid evolution of aquaculture involved a host of innovations of which many were based on R&D activities by public and private research organizations. Applied R&D tends to be the more effective the better focused it is on specific research problems or opportunities. Among the many possible aquaculture production systems on which aquaculture R&D might focus are recirculation aquaculture systems and in this paper we explore crucial aspects of the potential of urban recirculation aquaculture. Our exploration begins with a vision of recirculation aquaculture production plants located at the fringes of cities of converging economies. Such production systems are distinctly different from conventional urban aquaculture systems based on urban sewage. We scrutinize our vision from four perspectives: (i) the expected demand for aquaculture fish from urban consumers; (ii) cost competitiveness of fish produced at the fringes of cities as compared to fish produced in the rural hinterland; (iii) the potential for integration of urban recirculation aquaculture production into the modern food supply chains that are now emerging in converging economies, and (iv) the ecological footprint of aquaculture production compared to that of chicken production. Based on trends in the growth of urban populations world-wide and trends in demand for fish for food we estimate a total urban demand for aquaculture finfish between 11 and 51 million tons in 2025. We use von Thünen's location theory to provide support for the vision to locate recirculation aquaculture plants not within cities and not in their rural hinterland but on the fringes of cities. Moreover, we argue that tightly controlled recirculation aquaculture production would seem to be particularly well suited for being integrated into modern food supply chains. Finally, we compare the ecological footprint of recirculation aquaculture fish with that of industrially produced chicken and we find that the ecological balance depends on the source of energy used. We conclude our exploratory study with some thoughts on the implication for aquaculture R&D of the potential for recirculation aquaculture located on the fringes of cities in emerging economy countries. --

Die Fahrradergometrie in der arbeitsmedizinischen Vorsorge

A sufficiently high level of physical performance is of elementary importance for many occupational groups for coping with the daily work requirements. These include the fire brigade, police, military and also those employed in the construction industry, mining and agriculture. For the examination of the physical performance (bicycle) ergometry is available to the occupational physician as a standardized investigation, which is feasible under practical conditions. Taking the national and international guidelines and current scientific literature into consideration, the knowledge, prerequisites, indications and contraindications of ergometry that are necessary for the occupational physician are summarized. The recommendations for implementation are presented. Abort criteria in cases of pathological abnormalities or when the maximum workload is reached are listed. The advantages and disadvantages of gradual vs. ramp loading are shown. In addition to the physiologically expected reactions in this stress test, the limited sensitivity and specificity of ergometry for the diagnostics of coronary heart disease are discussed using examples of false positive and false negative ergometry examinations for men and women aged 50–59 years with unclear chest pains. Moreover, the different forms of ergometry and the partially limited comparability with each other and with real working conditions make the validity of bicycle ergometry for assessing the physical performance of a test person more difficult, since only the specific bicycle ergometric performance is tested. Therefore, despite the low complication rates in healthy and young volunteers, the use of bicycle ergometry in preventive occupational healthcare should not automatically be used in the assessment of physical performance for a subject’s employment in a particular workplace

Pattern representation and recognition with accelerated analog neuromorphic systems

Despite being originally inspired by the central nervous system, artificial neural networks have diverged from their biological archetypes as they have been remodeled to fit particular tasks. In this paper, we review several possibilites to reverse map these architectures to biologically more realistic spiking networks with the aim of emulating them on fast, low-power neuromorphic hardware. Since many of these devices employ analog components, which cannot be perfectly controlled, finding ways to compensate for the resulting effects represents a key challenge. Here, we discuss three different strategies to address this problem: the addition of auxiliary network components for stabilizing activity, the utilization of inherently robust architectures and a training method for hardware-emulated networks that functions without perfect knowledge of the system's dynamics and parameters. For all three scenarios, we corroborate our theoretical considerations with experimental results on accelerated analog neuromorphic platforms.Comment: accepted at ISCAS 201