Research Outputs

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    Publication
    “Doing What Matters in Times of Stress” to decrease psychological distress during Covid-19: a rammed controlled pilot trial
    (Wolters Kluwer Medknow Publications, 2022) Uygun, Ersin; Karaoğlan Kahiloğulları, Akfer; Department of Psychology; Department of Psychology; N/A; Acartürk, Ceren; Kurt, Gülşah; İlkkurşun, Zeynep; Faculty Member; Teaching Faculty; Master Student; Department of Psychology; College of Social Sciences and Humanities; College of Social Sciences and Humanities; Graduate School of Social Sciences and Humanities; 39271; 368619; N/A
    Despite the increasing psychological distress during Covid-19, utilisation of face-to-face psychological interventions decreased profoundly. The aim of this study involving two parallel, two-armed pilot randomised controlled trials was to examine the effectiveness of a guided self-help intervention "Doing What Matters in Times of Stress" (DWM) in decreasing psychological distress in Turkish and Syrian participants. Seventy-four Turkish nationals and 50 Syrian refugee adults with psychological distress were randomly allocated to a DWM group or wait-list control group. The primary outcome measure was the Patient Health Questionnaire 9 postintervention. Secondary outcome measures were the Generalised Anxiety Disorder Scale, posttraumatic stress disorder (PTSD) Checklist for DSM-5, Generalized Self-Efficacy Scale and Acceptance and Action Questionnaire-II postintervention. Although this study was not powered to detect a significant effect for DWM postassessment between DWM and the control group, results showed a significant improvement in depression symptoms among Turkish participants in the DWM group (d = 0.46) and in PTSD symptoms among Syrian participants in the DWM group (d = 0.67) from pre- to postintervention assessment. These results indicate the potential of DWM to decrease mental health problems during the pandemic and importance of a fully powered, definitive controlled trial to examine its effectiveness both for the host community and refugees to reduce psychological distress during Covid-19.
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    “Tell Me Your Story, I’ll Tell You What Makes It Meaningful’’: characterization of meaningful social interactions between intercultural strangers and design considerations for promoting them
    (Springer Science and Business Media Deutschland GmbH, 2021) N/A; Department of Sociology; Department of Media and Visual Arts; Department of Media and Visual Arts; Ramirez Galleguillos, María Laura; Eloiriachi, Aya; Serdar, Büşra; Coşkun, Aykut; PhD Student; Undergraduate Student; Master Student; Faculty Member; Department of Sociology; Department of Media and Visual Arts; Graduate School of Social Sciences and Humanities; College of Social Sciences and Humanities; College of Social Sciences and Humanities; College of Social Sciences and Humanities; N/A; N/A; N/A; 165306
    Positive meaningful interactions are encounters that promote positive attitudes and learning about others, which are needed to develop healthy social fabrics and cultural diversity. However, individuals tend to interact more with people like themselves often avoiding encounters with others that seem to be different, for example, with intercultural strangers. Though previous HCI work has been concerned with exploring meaningful experiences with products and technologies as a way of promoting product attachment, the field lacks studies exploring how design could facilitate intercultural MSI. Designing interventions to support intercultural MSI requires i) understanding what characteristics make these interactions meaningful and ii) how these characteristics can be addressed through design. In this study, we contribute to the literature by producing knowledge on these aspects. Based on an analysis of 56 real-life stories about intercultural MSI and an idea generation session with designers, we characterize intercultural MSI with four dimensions (outcomes, feelings, context, and elements) and we identify four design considerations to be taken into account when designing interventions to support intercultural MSI. Hence, our contribution is to formulate this knowledge while highlighting how the characteristics and perceptions of intercultural MSI can be applied to design new technologies that promote this kind of interaction. © 2021, Springer Nature Switzerland AG.
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    16.4: the optics of an autostereoscopic multiview display
    (SID, 2010) Baghsiahi, Hadi; Selviah, David R.; Willman, Eero; Fernández, Anibal; Day, Sally E.; Surman, Phil A.; N/A; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Erden, Erdem; Chellappan, Kishore Velichappattu; Ürey, Hakan; Master Student; Researcher; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; N/A; N/A; 8579
    An autostereoscopic head-tracked back projection display that uses an RGB laser illumination source and a fast light engine is described. Images are horizontally scanned columns controlled by a spatial light modulator that directs two or more images in the directions of the apposite viewers 'eyes.
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    2D scanning MEMS stage integrated with microlens arrays for high-resolution beam steering
    (IEEE, 2009) Department of Electrical and Electronics Engineering; N/A; Department of Electrical and Electronics Engineering; N/A; N/A; N/A; Ürey, Hakan; Gökçe, Sertan Kutal; Holmstrom, Sven; Arslan, Aslıhan; Ataman, Çağlar; Seren, Hüseyin Rahmi; Faculty Member; Master Student; Researcher; Master Student; PhD Student; Master Student; Other; Department of Electrical and Electronics Engineering; College of Engineering; Graduate School of Sciences and Engineering; College of Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; N/A; 8579; N/A; N/A; N/A; N/A; N/A; N/A
    A novel MEMS stage using one set of comb fingers, capable of 2-axis motion is designed and developed. With an integrated 1.1mm square microlens-array it deflects 40um in-plane at 60V and 95um out-of-plane at 100V.
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    3D articulated shape segmentation using motion information
    (Institute of Electrical and Electronics Engineers (IEEE), 2010) Department of Computer Engineering; N/A; Yemez, Yücel; Kalafatlar, Emre; Faculty Member; Master Student; Department of Computer Engineering; College of Engineering; Graduate School of Sciences and Engineering; 107907; N/A
    We present a method for segmentation of articulated 3D shapes by incorporating the motion information obtained from time-varying models. We assume that the articulated shape is given in the form of a mesh sequence with fixed connectivity so that the inter-frame vertex correspondences, hence the vertex movements, are known a priori. We use different postures of an articulated shape in multiple frames to constitute an affinity matrix which encodes both temporal and spatial similarities between surface points. The shape is then decomposed into segments in spectral domain based on the affinity matrix using a standard K-means clustering algorithm. The performance of the proposed segmentation method is demonstrated on the mesh sequence of a human actor.
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    PublicationOpen Access
    3D bioprinted organ?on?chips
    (Wiley, 2022) Mustafaoğlu, Nur; Zhang, Yu Shrike; Department of Mechanical Engineering; N/A; N/A; Dabbagh, Sajjad Rahmani; Sarabi, Misagh Rezapour; Birtek, Mehmet Tuğrul; Taşoğlu, Savaş; Faculty Member; Department of Mechanical Engineering; KU Arçelik Research Center for Creative Industries (KUAR) / KU Arçelik Yaratıcı Endüstriler Uygulama ve Araştırma Merkezi (KUAR); Koç Üniversitesi İş Bankası Yapay Zeka Uygulama ve Araştırma Merkezi (KUIS AI)/ Koç University İş Bank Artificial Intelligence Center (KUIS AI); College of Engineering; Graduate School of Social Sciences and Humanities; Graduate School of Sciences and Engineering; N/A; N/A; N/A; 291971
    Organ-on-a-chip (OOC) platforms recapitulate human in vivo-like conditions more realistically compared to many animal models and conventional two-dimensional cell cultures. OOC setups benefit from continuous perfusion of cell cultures through microfluidic channels, which promotes cell viability and activities. Moreover, microfluidic chips allow the integration of biosensors for real-time monitoring and analysis of cell interactions and responses to administered drugs. Three-dimensional (3D) bioprinting enables the fabrication of multicell OOC platforms with sophisticated 3D structures that more closely mimic human tissues. 3D-bioprinted OOC platforms are promising tools for understanding the functions of organs, disruptive influences of diseases on organ functionality, and screening the efficacy as well as toxicity of drugs on organs. Here, common 3D bioprinting techniques, advantages, and limitations of each method are reviewed. Additionally, recent advances, applications, and potentials of 3D-bioprinted OOC platforms for emulating various human organs are presented. Last, current challenges and future perspectives of OOC platforms are discussed.
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    3D shape correspondence by isometry-driven greedy optimization
    (IEEE Computer Soc, 2010) N/A; Department of Computer Engineering; Sahillioğlu, Yusuf; Yemez, Yücel; PhD Student; Faculty Member; Department of Computer Engineering; Graduate School of Sciences and Engineering; College of Engineering; 215195; 107907
    We present an automatic method that establishes 3D correspondence between isometric shapes. Our goal is to find an optimal correspondence between two given (nearly) isometric shapes, that minimizes the amount of deviation from isometry. We cast the problem as a complete surface correspondence problem. Our method first divides the given shapes to be matched into surface patches of equal area and then seeks for a mapping between the patch centers which we refer to as base vertices. Hence the correspondence is established in a fast and robust manner at a relatively coarse level as imposed by the patch radius. We optimize the isometry cost in two steps. in the first step, the base vertices are transformed into spectral domain based on geodesic affinity, where the isometry errors are minimized in polynomial time by complete bipartite graph matching. the resulting correspondence serves as a good initialization for the second step of optimization in which we explicitly minimize the isometry cost via an iterative greedy algorithm in the original 3D Euclidean space. We demonstrate the performance of our method on various isometric (or nearly isometric) pairs of shapes for some of which the ground-truth correspondence is available.
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    3D shape recovery and tracking from multi-camera video sequences via surface deformation
    (Institute of Electrical and Electronics Engineers (IEEE), 2006) Skala, V.; N/A; Department of Computer Engineering; Sahillioğlu, Yusuf; Yemez, Yücel; PhD Student; Faculty Member; Department of Computer Engineering; Graduate School of Sciences and Engineering; College of Engineering; 215195; 107907
    This paper addresses 3D reconstruction and modeling of time-varying real objects using multicamera video. The work consists of two phases. In the first phase, the initial shape of the object is recovered from its silhouettes using a surface deformation model. The same deformation model is also employed in the second phase to track the recovered initial shape through the time-varying silhouette information by surface evolution. The surface deformation/evolution model allows us to construct a spatially and temporally smooth surface mesh representation having fixed connectivity. This eventually leads to an overall space-time representation that preserves the semantics of the underlying motion and that is much more efficient to process, to visualize, to store and to transmit. / Bu makale, çok kameralı video kullanarak zamanla değişen gerçek nesnelerin 3B yeniden yapılandırılmasını ve modellenmesini ele almaktadır. Çalışma iki aşamadan oluşmaktadır. İlk aşamada, nesnenin ilk şekli, bir yüzey deformasyon modeli kullanılarak silüetlerinden kurtarılır. Aynı deformasyon modeli, ikinci aşamada, yüzey evrimi yoluyla zamanla değişen siluet bilgisi yoluyla geri kazanılan ilk şekli izlemek için de kullanılır. Yüzey deformasyonu/evrimi modeli, sabit bağlantıya sahip uzamsal ve zamansal olarak pürüzsüz bir yüzey ağ temsili oluşturmamıza izin verir. Bu, sonunda, altta yatan hareketin anlamını koruyan ve işlemesi, görselleştirmesi, depolaması ve iletmesi çok daha verimli olan genel bir uzay-zaman temsiline yol açar.
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    PublicationOpen Access
    3D-printed microneedles in biomedical applications
    (Elsevier, 2021) Rahbarghazi, Reza; Yetişen, Ali Kemal; N/A; Department of Mechanical Engineering; Dabbagh, Sajjad Rahmani; Sarabi, Misagh Rezapour; Sokullu, Emel; Taşoğlu, Savaş; Faculty Member; Faculty Member; Department of Mechanical Engineering; KU Arçelik Research Center for Creative Industries (KUAR) / KU Arçelik Yaratıcı Endüstriler Uygulama ve Araştırma Merkezi (KUAR); Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); Graduate School of Social Sciences and Humanities; Graduate School of Sciences and Engineering; School of Medicine; College of Engineering; N/A; N/A; 163024; 291971
    Conventional needle technologies can be advanced with emerging nano- and micro-fabrication methods to fabricate microneedles. Nano-/micro-fabricated microneedles seek to mitigate penetration pain and tissue damage, as well as providing accurately controlled robust channels for administrating bioagents and collecting body fluids. Here, design and 3D printing strategies of microneedles are discussed with emerging applications in biomedical devices and healthcare technologies. 3D printing offers customization, cost-efficiency, a rapid turnaround time between design iterations, and enhanced accessibility. Increasing the printing resolution, the accuracy of the features, and the accessibility of low-cost raw printing materials have empowered 3D printing to be utilized for the fabrication of microneedle platforms. The development of 3D-printed microneedles has enabled the evolution of pain-free controlled release drug delivery systems, devices for extracting fluids from the cutaneous tissue, biosignal acquisition, and point-of-care diagnostic devices in personalized medicine.
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    48.4: Beam forming for a laser based auto-stereoscopic multi-viewer display
    (Blackwell Publishing Ltd, 2011) Baghsiahi, Hadi; Selviah, David R.; Willman, Eero; Fernández, Anibal; Day, Sally E.; Surman, Phil A.; N/A; Department of Electrical and Electronics Engineering; N/A; N/A; N/A; Department of Electrical and Electronics Engineering; Akşit, Kaan; Ölçer, Selim; Mostafazadeh, Aref; Erden, Erdem; Chellappan, Kishore Velichappattu; Ürey, Hakan; PhD Student; Other; N/A; Other; N/A; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; N/A; College of Engineering; N/A; N/A; N/A; N/A; N/A; 8579
    An auto-stereoscopic back projection display using a RGB multiemitter laser illumination source and micro-optics to provide a wider view is described. The laser optical properties and the speckle due to the optical system configuration and its diffusers are characterised. © 2011 SID.