Browsing by Subject "Activity"

Now showing 1 - 7 of 7

Open Access
Activity analysis for assistive systems
(2014) İşcen, Ahmet
Although understanding and analyzing human actions is a popular research topic in computer vision, most of the research has focused on recognizing ”ordinary” actions, such as walking and jumping. Extending these methods for more specific domains, such as assistive technologies, is not a trivial task. In most cases, these applications contain more fine-grained activities with low inter-class variance and high intra-class variance. In this thesis, we propose to use motion information from snippets, or small video intervals, in order to recognize actions from daily activities. Proposed method encodes the motion by considering the motion statistics, such as the variance and the length of trajectories. It also encodes the position information by using a spatial grid. We show that such approach is especially helpful for the domain of medical device usage, which contains actions with fast movements Another contribution that we propose is to model the sequential information of actions by the order in which they occur. This is especially useful for fine-grained activities, such as cooking activities, where the visual information may not be enough to distinguish between different actions. As for the visual perspective of the problem, we propose to combine multiple visual descriptors by weighing their confidence values. Our experiments show that, temporal sequence model and the fusion of multiple descriptors significantly improve the performance when used together.
Open Access
Alteration of self-assembled patterns by microorganisms in evaporating droplets
(2016-08) Andaç, Tuğba
The science of self-organization comprises a diverse range of processes where a disordered system of components form ordered pattern or structure spontaneously without any external instruction [1]. Plentiful examples of this phenomenon appear in nature at almost all scales [2]. Over the past decades, self-assembly has become the apple of many researchers eye by offering breakthroughs for many applications in not only physics but also chemistry, biology and material sciences [3]. Among several self-assembly methods, using evaporating droplets shines out as it provides ease and simplicity. Along with these advantages, it increases its popularity by providing the opportunity of obtaining a variety of patterns such as uniform depositions, central bumps, polygons and hexagons [4] and more famously (coffee) rings [5]. Nonetheless, most of the studies resulting in these patterns have been carried out by using Brownian particles which uctuate randomly due to the collisions with the molecules of the surrounding uid, while only little is known when it comes to active particles suspended in evaporating droplets. The self-propelling nature of active particles [6] permits them to explore their environment differently from Brownian particles and opens new doors in this research line. Being in the quest of understanding what will happen in the presence of active particles such as the well-studied bacteria Esherichia coli (E.coli ), we investigate and explore the self-assembled patterns in evaporating droplets by using digital video microscopy. We demonstrate that the presence of E.coli bacteria tunes the self-assembled patterns. Moreover, we enrich the patterns by introducing salt. We show that the activity of these microorganisms has an in- uence on salt crystallization based on the characteristic dendritic crystals obtained with active and motile bacteria and unaltered, regular crystals obtained with nonmotile bacteria with inhibited activity. Our results suggest a simpler, faster and cheaper method in which common salt can be used as a biomarker to detect bacterial activity.
Open Access
Correction to: Sexual horn dimorphism predicts the expression of active personality trait: males perform better only in the sexually horn dimorphic Onthophagus dung beetle
(Springer Japan KK, 2025-01-05) Kerman, Kaan; Angela, R.; Antonio, R.; Claudia, P.
In this article Table 3 caption was incorrectly given as ‘Parameter estimates of the main mixed effect models for O. ruficapillus and O. furcatus. Behavioral measures are factored as response variables and transformed prior to analysis sex, body size, and the interaction term are con sidered as fixed effects in the model. Individual identity is used as a random effect. Fixed effects are scaled for easier comparison between models. Standardized coefficients (β) are reported with 95% confidence intervals. Significant esti mates are given in bold.’ The correct caption should have read ‘Parameter estimates of the main mixed effect models for O. ruficapillus and O. furcatus. Behavioral measures are factored as response variables and transformed prior to analysis sex, body size, and the interaction term are con sidered as fixed effects in the model. Individual identity is used as a random effect. Fixed effects are scaled for easier comparison between models. Unstandardized coefficients (β) are reported with 95% confidence intervals. Significant estimates are given in bold.’ The original article has been corrected.
Open Access
Highly-dispersed iridium catalysts with sub-nanometer diameters for carbon monoxide oxidation
(2021-09) Hosseini, Seyedsaber
Novel catalytic architectures composed of catalytic centers with sub-nanometer diameters for CO oxidation reaction were designed, synthesized, and characterized. Accordingly, well-dispersed iridium precious metal active sites were supported on various catalytic support materials. Namely, magnesium oxide (MgO), ceria (CeO2), lanthana-zirconia (La2O3–ZrO2) and titania-zirconia (TiO2–ZrO2) systems were chosen as different support systems. The favorable catalytic effect of highly-dispersed Ir active sites with sub-nanometer diameters were demonstrated in flow-mode catalytic performance tests, where the lower loadings of highly dispersed Ir sites showed comparable catalytic activity in CO oxidation to that of bigger Ir clusters with higher metal loading. Furthermore, influence of the catalyst pre-treatment conditions (e.g., reduction in H2, oxidation in O2, and calcination in air) on the catalyst structure and performance were also studied via XRD, Raman, BET, XPS, TEM, EDX, and in-situ FTIR spectroscopy techniques. Our results indicate that in all the catalytic systems, high-dispersion Ir sites can be generated on supports where Ir exists as small clusters with < 1 nm particle size. Moreover, catalyst pretreatment conditions revealed noticeable alterations in the catalyst structure in terms of average support particle size, reduction extent of the support, specific surface area, pore volume, pore size, and Ir oxidation state. Finally, catalytic performance results indicated that under reaction conditions yielding close to 100% CO conversion, 0.2 and 0.5 wt.% Ir catalysts led to comparable performance to that of 1 wt.% Ir catalyst demonstrating the advantage of catalytic systems with highly dispersed sub-nanometer diameter active sites with extremely low metal loading.
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HSBC Türkiye’nin tarihi
(Bilkent University, 2021) Bistren, Mehmet Kaan; Öztaş, Bora; Yılmaz, Taha; Takım, Muhammet Onur
HSBC, 1990 yılında Türkiye’de Midland Bank ismiyle faaliyetlerine başladı. Türkiye’de yatırım yapan ilk İngiliz bankası olmasıyla birlikte Türkiye’deki ilk yabancı sermayeli bankalardan da biridir. HSBC Türkiye’de kurulduğu tarihten itibaren Türk bankacılık sektörünün dışa açılmasında önemli rol oynadı. Buna ek olarak Demir Bank’ı satın alması, elde ettiği çeşitli başarılar, kazandığı ödüller ve 2003’teki bombalı saldırı ile medyada birçok kez gündeme geldi. Bu makale HSBC’nin Türkiye’ye giriş yaptığı dönemdeki Türk bankacılığıyla birlikte HSBC Türkiye’nin önemli faaliyetlerinin tarihini inceleyecek ve HSBC’nin hangi alanlarda farklı bir banka olduğunu açıklayacaktır.
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Polatlı Belediyespor Kadın Hentbol Takımı'nın tarihi
(Bilkent University, 2020) İşsever, Defne; Eviz, Efe Musa; Baysal, Ceren; Gürsoy, Kaan; Temimhan, Yasemin
Araştırma konumuz Polatlı Belediyespor Kadın Hentbol Takımı tarihi olup öncelikle hentbolun genel tarihi araştırılmış ve Polatlı Belediyesi'nin spor üzerine yaptığı çalışmalar ortaya konulmuştur. Polatlı Belediyesi'nin spor ile ilgili yürüttüğü projeler arasında hentbolun yanında futbol, tekvando, yüzme, voleybol ve atletizm alanındaki çalışmaları da araştırma konusunun bir kısmında bulunmaktadır. Polatlı Belediyesi'nin belirtilen spor dallarındaki aktifliği incelenerek ve özellikle kadın hentbol takımının tarihi araştırılarak, geçmişten günümüze başarı aşamaları kaydedilmiştir. Hentbolun tarihinden itibaren, hentbol sporunun Türkiye'ye gelişi, Polatlı Belediyespor'un tarihi ve hentbolun bu kulübe kazandırılmasına kadar geçen süre ele alınarak tarihi müsabakalardaki başarılar ve mağlubiyetler incelenmiştir. "Hentbol nasıl bulundu?", "Nasıl bir yol izledi?", "Türkiye'ye geldikten sonra hentbol ülkeye neler kazandırdı?" ve "Polatlı Belediyespor hentbolla nasıl tanıştı?" gibi sorular araştırmanın içerisinde verilmeye çalışılmıştır. Özellikle Polatlı Belediyespor Kadın Hentbol takımının yakın tarihimizde elde ettiği başarılar ve takımın izlediği doğrultu, otuz senelik bir zaman dilimini içerisinde incelenmiş, araştırmacıya ölçme ve kıyaslama becerileri kazandırmıştır. Okuyucuya az bilinen, yerel takımların tarihi hakkında izlenim kazandırılmaya çalışılmıştır.
Open Access
Searching for complex human activities with no visual examples
(2008) Ikizler, N.; Forsyth, D.A.
We describe a method of representing human activities that allows a collection of motions to be queried without examples, using a simple and effective query language. Our approach is based on units of activity at segments of the body, that can be composed across space and across the body to produce complex queries. The presence of search units is inferred automatically by tracking the body, lifting the tracks to 3D and comparing to models trained using motion capture data. Our models of short time scale limb behaviour are built using labelled motion capture set. We show results for a large range of queries applied to a collection of complex motion and activity. We compare with discriminative methods applied to tracker data; our method offers significantly improved performance. We show experimental evidence that our method is robust to view direction and is unaffected by some important changes of clothing. © 2008 Springer Science+Business Media, LLC.