562 research outputs found
On the use of ultraviolet photography and ultraviolet wing patterns in butterfly morphology and taxonomy
In a series of feeding experiments we found that, depending on the larval food plant species or part of food plant ingested, individuals of the blue butterfly Polyommatus icarus (Lycaenidae) exhibit broad variation of wing patterns in the ultraviolet (UV) range of wavelengths which is invisible to humans. Such intraspecific variability in UV wing patterns has been underestimated thus far due to the rather demanding approach needed to study these patterns. We discuss methodological problems with the assessment of butterfly UV wing patterns by UV photography. Given proper standardization, UV photography is a suitable method to qualitatively assess UV wing patterns for possible use in morphology or systematics. Spectrophotometly should preferably be used as quantitative method when consideling UV wing patterns in a communication context. No higher value should be attached to UV wing patterns as compared to human visible wing patterns
Thermal and colour data fusion for people detection and tracking
Thesis (MSc)--Stellenbosch University, 2014.ENGLISH ABSTRACT: In this thesiswe approach the problem of tracking multiple people individually in a video sequence.
Automatic object detection and tracking is non-trivial as humans have complex and
mostly unpredictable movements, and there are sensor noise and measurement uncertainties
present. We consider traditional object detection methods and decide to use thermal
data for the detection step. This choice is supported by the robustness of thermal data compared
to colour data in unfavourable lighting conditions and in surveillance applications. A
drawback of using thermal data is that we lose colour information, since the sensor interprets
the heat emission of the body rather than visible light. We incorporate a colour sensor
which is used to build features for each detected object. These features are used to help
determine correspondences in detected objects over time.
A problem with traditional blob detection algorithms, which typically consist of background
subtraction followed by connected-component labelling, is that objects can appear to split
or merge, or disappear in a few frames. We decide to add âdummyâ blobs in an effort to
counteract these problems. We refrain from making any hard decisions with respect to the
blob correspondences over time, and rather let the system decide which correspondences
are more probable. Furthermore, we find that the traditional Markovian approach of determining
correspondences between detected blobs in the current time step and only the
previous time step can lead to unwanted behaviour. We rather consider a sequence of time
steps and optimize the tracking across them. We build a composite correspondence model
and weigh each correspondence according to similarity (correlation) in object features. All
possible tracks are determined through this model and a likelihood is calculated for each.
Using the best scoring tracks we then label all the detections and use this labelling as measurement
input for a tracking filter.
We find that the window tracking approach shows promise even though the data we us for
testing is of poor quality and noisy. The system struggles with cluttered scenes and when a
lot of dummy nodes are present. Nonetheless our findings act as a proof of concept and we
discuss a few future improvements that can be considered.AFRIKAANSE OPSOMMING: In hierdie tesis benader ons die probleemomverskeiemense individueel in ân video-opname
op te spoor en te volg. Outomatiese voorwerp-opsporing en -volging is nie-triviaal, want
mense het komplekse en meestal onvoorspelbare bewegings, en daar is sensor-ruis en metingonsekerhede
teenwoordig. Ons neem tradisionele voorwerp-opsporing metodes in ag
en besluit om termiese data te gebruik vir die opsporingstap. Hierdie keuse word ondersteun
deur die robuustheid van termiese data in vergelyking met kleur data in ongunstige
lig-kondisies en in sekuriteitstoepassings. Die nadeel van die gebruik van termiese data is
dat ons kleur inligting verloor, aangesien die sensor die hitte vrystelling van die liggaam interpreteer,
eerder as sigbare lig. Ons inkorporeer ân kleur-sensor wat gebruik word om die
kenmerke van elke gevolgde voorwerp te bou. Hierdie kenmerke word gebruik om te help
om ooreenkomste tussen opgespoorde voorwerpe te bepaal met die verloop van tyd.
ân Probleem met die tradisionele voorwerp-opsporing algoritmes, wat tipies bestaan uit agtergrond-
aftrekking gevolg deur komponent-etikettering, is dat dit kan voorkom asof voorwerpe
verdeel of saamsmelt, of verdwyn in ân paar rame. Ons besluit om âflousâ-voorwerpe
by te voeg in ân poging om hierdie probleme teen te werk. Ons weerhou om enige konkrete
besluite oor opgespoorde voorwerpe se ooreenkomste met die verloop van tyd te maak, en
laat die stelsel eerder toe om te besluit watter ooreenkomste meer waarskynlik is. Verder
vind ons dat die tradisionele Markoviaanse benadering vir die bepaling van ooreenkomste
tussen opgespoorde voorwerpe in die huidige tydstap en die vorige een kan lei tot ongewenste
gedrag. Ons oorweeg eerder ân reeks van tydstappe, of ân venster, en optimeer die
volg van voorwerpe oor hulle. Ons bou ân saamgestelde ooreenstemmingsmodel en weeg
elke ooreenstemming volgens die ooreenkoms (korrelasie) tussen voorwerpe se kenmerke.
Alle moontlike spore word deur hierdie model bepaal en ân waarskynlikheid word bereken
vir elkeen. Die spore met die beste tellings word gebruik om al die opsporings te nommeer,
en hierdie etikettering word gebruik as meting-inset vir ân volgingsfilter.
Ons vind dat die venster-volg benadering belowend vaar selfs al is die invoerdata in ons
toetse van swak gehalte en ruiserig. Die stelsel sukkel met besige tonele en wanneer baie
flous-voorwerpe teenwoordig is. Tog dien ons bevindinge as ân bewys van konsep en ons
bespreek ân paar verbeterings wat in die toekoms oorweeg kan word
Issues of shaping the studentsâ professional and terminological competence in science area of expertise in the sustainable development era
The paper deals with the problem of future biology teachersâ vocational preparation process and shaping in them of those capacities that contribute to the conservation and enhancement of our planetâs biodiversity as a reflection of the leading sustainable development goals of society. Such personality traits are viewed through the prism of forming the future biology teachersâ professional and terminological competence. The main aspects and categories that characterize the professional and terminological competence of future biology teachers, including terminology, nomenclature, term, nomen and term element, have been explained. The criteria and stages of shaping the future biology teachersâ professional and terminological competence during the vocational training process have been fixed. Methods, techniques, technologies, guiding principles and forms of staged work on the forming of an active terminological dictionary of students have been described and specified. The content of the distant special course âLatin. Botanical Terminologyâ, which provides training for future teachers to study the professional subjects and to understand of international scientific terminology, has been presented. It is concluded that the proper level of formation of the future biology teachersâ professional and terminological competence will eventually ensure the qualitative preparation of pupils for life in a sustainable development era
Aerospace medicine and biology: A continuing bibliography with indexes
This bibliography lists 138 reports, articles, and other documents introduced into the NASA scientific and technical information system in Jun. 1980
Towards the Energy Transition of the Building Stock with BIPV: Innovations, Gaps and Potential Steps for a Widespread Use of Multifunctional PV Components in the Building Envelope
The scenario that emerges from scientific research on the use of BIPV systems in architecture shows that photovoltaic technologies and systems have reached a significant development in production and installation, becoming a strategic approach in the field of energy efficiency and enabling a progressive decarbonisation of the building stock. Still, knowledge and methods of architectural integration are not fully developed, especially in Italy. The present paper reports the results of a research activity that, systematising the main criteria and indicators for assessing the integrability of BIPVs in architecture, has led to the development of BIPV Product and Case Study Catalogues that define an up-to-date state of the art on aspects of design and technological innovation using BIPV systems and components. Catalogues have been created with the objective of contributing to the growth of knowledge on the most up-to-date methods of design by implementing a âtechnology transferâ from good practice, in which photovoltaic systems are an integral part of the design concept and construction techniques of the architecture. The analysis related to the production of BIPV systems and components and their application in architectural projects allows one to highlight the main critical factors in the diffusion throughout the country and to identify the main research demand arising from the specific national situation
2018 Student Spotlight on Research Proceedings
ESF\u27s annual Spotlight on Student Research is a dynamic forum where graduate and undergraduate students share the results of their research and community service projects. The Spotlight is a student poster session highlighting scholarly efforts
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