5916 research outputs found
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Design-based research in human-computer interaction: A scoping review
No full textInspired by the use of design-based research (DBR) in the learning sciences, in this paper, we discuss the promise of applying and adapting DBR in Human-Computer Interaction (HCI). Although much research in HCI is related to learning interventions and educational contexts, the use of DBR is scarce. We argue that DBR as a research approach can help develop the field, by explicitly grounding research design and interventions in theory, foster better impact beyond project completion, and bridge theory and practice through clarified knowledge contributions. Grounded in the characteristics of DBR, and based on a scoping review, this paper provides a timely snapshot of existing DBR practices and research contributions in HCI. Based on this, we will discuss further implications and opportunities for the development and application of DBR in the HCI field.Det Frie Forskningsrad (DFF
Seismic microzonation; Past, present and future
No full textThe purpose of seismic microzonation has always been to estimate earthquake ground motion characteristics on the ground surface based on available geological, seismological and geotechnical data. During the early years, mostly geological data and observations from past earthquakes were used to prepare microzonation maps. In more recent years, regional earthquake hazard studies, geotechnical investigations, and site response analysis became more common. The uncertainties in source characteristics, soil profile, soil properties, and the characteristics of the building inventory can be considered as critical issues associated with these analyses. In the first stage, the probabilistic distribution of the related earthquake parameters on the ground surface may be determined considering all possible input acceleration time histories, site profiles, and dynamic soil properties. Generally, to account for the variability in earthquake source and path effects it is suggested to use more than 20 acceleration records compatible with the site-dependent earthquake hazard. Likewise, more or equal to 100 soil profiles generated by Monte Carlo simulations may be used to account for the variability of site conditions. Then the seismic microzonation in a specific area may be based on the probabilistic assessment of these factors in site response analysis. An attempt will be made to briefly review the past, present and possibilities for future studies on microzonation applications.TÜBİTAKPublisher versio
A robust and gain-free direct model predictive control for nine-level t-type converter
No full textModel predictive control (MPC) is a powerful strategy for tackling multiobjective control challenges, but it often involves a laborious process of tuning weighting factors. This article proposes a gain-free MPC method for a recently developed nine-level T-type converter (9L-T-2C), which offers advantages over traditional topologies, such as fewer components and improved efficiency. Drawing inspiration from Lyapunov's theory, this method avoids the use of weighting factors while effectively handling three targets, including current tracking, balancing of flying capacitors (FCs), and regulation of the neutral point (NP). Comparable with the traditional finite-control-set MPC (FCS-MPC), the proposed controller demonstrates high performance concerning all objectives. Additionally, it showcases superior resilience against model uncertainties when compared with the traditional approach. Experimental validation of the proposed MPC method is conducted in grid-connected operation under several conditions. The proposed method is subjected to a comparative analysis via the experimental implementation, where it is compared with a proportional-resonant (PR) controller and other state-of-the- art MPC methods. This analysis reveals the advantages of the proposed method, including eliminating the need for gains or weighting factors, improved robustness, and effective control of the FCs.Deutscher Akademischer Austauschdienst ; German Academic Exchange Service ; Technische Universität München ; Agencia Nacional de Investigación y Desarrollo ; Agencia Nacional de Investigación y Desarroll
A multi-functional nanoplatform of trastuzumab/β-estradiol functionalized rose bengal- barium titanate nanoparticles for targeted photothermal/photodynamic cancer therapy
No full textSignificant efforts focus on developing non-invasive, targeted cancer therapies, with photothermal (PTT) and photodynamic (PDT) approaches showing strong potential. This study reports the synthesis of Rose Bengal–Barium Titanate nanoparticles (BTRB), coated with Polydopamine (PDA) and functionalized with Trastuzumab (TRZ) or β-Estradiol (EST), for PTT and PDT. BTRB@PDA nanoparticles were prepared by layer-by-layer assembly followed by PDA coating. Under 808 nm laser irradiation, BTRB@PDA nanoparticles caused the temperature to rise to 45 °C, leading to an ∼80 % reduction in MCF7 and SKBR3 cell viability. For PDT, the BT core converts a 1030 nm femtosecond (fs) laser into 515 nm light via second harmonic generation (SHG). This 515 nm emission activates the RB photosensitizer, leading to the production of reactive oxygen species (ROS), detected by the Diphenylisobenzofuran (DPBF) indicator and resulting in a 20 % reduction in cell viability. Targeting efficacy was demonstrated by higher uptake of EST- and TRZ-functionalized nanoparticles by MCF7 and SKBR3 cells, respectively, compared to healthy MCF12A cells. Excess ROS induced oxidative stress, mitochondrial dysfunction, DNA damage, and apoptosis. TRZ-functionalized nanoparticles also caused G1 phase arrest in SKBR3 cells, suppressing proliferation. These findings demonstrate that TRZ–EST functionalized BTRB@PDA nanoparticles present a promising multifunctional therapeutic platform with switchable modes for PTT and PDT cancer therapy, exploiting the photothermal properties of PDA and the photodynamic activity of Rose Bengal.TÜBİTA
RTF: Reputation-based team formation approach for enhancing dependable critical fully autonomous multi-UAV BVLOS operations
No full textThe development of autonomous multi-unmanned aerial vehicles, or multi-UAVs, represents significant progress in various fields, including the military, business, and civilian sectors. As this innovative field develops, the necessity of creating models that guarantee the fundamental components of security, privacy, dependability, effectiveness, and safety is growing. Based on this observation, this research suggests a reputation-based team formation (RTF) approach that rates each UAV according to the level of services it provides. Such a system is essential for critical multi-UAV Beyond Visual Line of Sight (BVLOS) operations requiring high dependability, effectiveness, safety, and privacy protection. To validate RTF's effectiveness, we focus on a simulation scenario where multi-UAVs are deployed to localize a target in a forest where a fire is spreading. The criticality of this operation is underscored by the need to locate the target before the fire reaches it. Our results demonstrate that RTF successfully enables cooperative UAVs to block malicious ones and significantly reduce their influence, even in the presence of multiple compromised UAVs. © 2025 The Authors.Publisher versio
Reducción del riesgo de corrosión de materiales a base de cemento mezclados con agua de mar
No full textThe objective of this study is to reduce the amount of free chloride that causes corrosion by employing different binders and to attain the free chloride level permitted by the relevant standards. The chloride content was determined by the X-ray fluorescence method. It was observed that the chloride binding capacity increased when the CaO/Al₂O₃ ratio decreased up to 4-6. On the other hand, it was determined that the chloride binding capacity decreased slightly when the CaCO3/Al₂O₃ ratio increased from 0 to 0.3-0.5, though no significant effect was observed after 0.5. The majority of binders demonstrated results below the maximum chloride level determined by the standards, which is a great opportunity to use seawater as mixing water for reinforced concrete.Boğaziçi ÜniversitesiPublisher versio
Multifunctional evaluation of urban green infrastructure for combating climate change: A case of Sancaktepe district in Istanbul metropolitan city
No full textUrban areas worldwide are increasingly facing environmental challenges due to rapid urbanization and climate change. Phenomena such as urban heat islands (UHI), carbon emissions, and biodiversity loss significantly impact human health and urban livability. In response, Urban Green Infrastructure (UGI) has emerged as a key strategy, linking environmental sustainability with spatial planning to promote climate resilience and sustainable development. This study evaluates the multifunctional effectiveness of UGI in mitigating climate - related impacts in Sancaktepe, a rapidly urbanizing district in Istanbul that has developed informally over environmentally sensitive land. Despite these pressures, Sancaktepe demonstrates substantial UGI potential, as indicated by data from the Istanbul Green Area Management System (YAYSIS). The evaluation focuses on four main functions: UHI mitigation, biodiversity enhancement, ecological corridor potential, and carbon sequestration. Land Surface Temperature (LST) was used to assess UHI mitigation capacity, and results show that natural vegetative zones maintain significantly lower surface temperatures than plantation areas, emphasizing the cooling effect of mature green systems. Biodiversity assessment revealed that the district includes 224 plant taxa and 10 endemic species, primarily concentrated in the Ömerli Basin and Aydos Forest. These preserved regions also support six distinct habitat types and reflect the district’s high ecological value. Carbon sequestration analysis indicates that plantation efforts across Sancaktepe's settlement areas contribute approximately 2,139,610 tons of carbon storage, although natural vegetation areas exhibit greater per - area sequestration capacity. A composite Urban Green Infrastructure Performance Index (UGI - PI) was developed to spatially synthesize these indicators using three parameters: Normalized Difference Vegetation Index (NDVI), Land Surface Temperature (LST), and Normalized Difference Built - up Index (NDBI). Each indicator was normalized, and the resulting index was classified into five performance categories using equal interval classification. The UGI - PI map reveals significant spatial variation: northern and eastern areas (including the Ömerli and Aydos zones) score very high in terms of UGI effectiveness, while central and southern urban neighborhoods score low due to high built - up intensity, reduced vegetation cover, and elevated surface temperatures. These low - performing areas are less effective under current conditions but may benefit from targeted small - scale interventions such as tree planting, vertical greening, and pocket parks. The integration of UGI - PI enhances the research by providing a spatial decision - support tool that identifies both conservation - priority zones and vulnerable areas requiring improvement. This framework not only evaluates the current performance of UGI systems but also contributes to strategic climate adaptation planning. The findings reinforce the need to protect natural vegetative zones while implementing targeted urban greening strategies in climate - stressed districts like Sancaktepe.Publisher versio
Chemical composition and reactivity of quercus pubescens bark and bark fractions for thermochemical biorefinery application
No full textAdvancing circular bioeconomy in thermochemical biorefineries requires species-specific data that link biomass composition and thermochemical performance. Here, we provide the first integrated thermochemical dataset for Quercus pubescens bark combining FT-IR, XRD, XRF, TGA, and measured ash fusion temperatures (AFT). The results reveal that bark is enriched in phenolic extractives (21.2%) and inorganics (15%), with calcium oxalate monohydrate (COM) dominating the inorganic fraction, as confirmed by FT-IR and XRD. Thermal decomposition occurs between 150 °C and 690 °C. Pyrolysis follows diffusion-controlled kinetics, with apparent activation energies for bark and its fractions ranging between 70 and 103 kJ mol−1. Extraction increases the activation energy of bark. The ash exhibits a high AFT (softening: 1421 °C, flow: 1467 °C), placing this feedstock within the low-slagging, moderate-fouling range compared to other lignocellulosics. The observed COM-to-CaCO3/CaO transformation upon heating contributes to the elevated AFT. Reactivity analyses of bark fractions support thermochemical biorefinery routing of fractions: extracted bark (EB) and desuberinised bark (DB) are highly reactive and well-suited to combustion/gasification, whereas raw bark (B) and Klason lignin (KL) exhibit higher thermal stability and yield more persistent char, favoring slow pyrolysis for biochar production. Such routing strategies optimize energy recovery and also enable co-products with environmental co-benefits
Dynamic relief provision planning for en route refugees: Modeling probabilistic movements using migration pull drivers
No full textForced displacement crises have become a pressing humanitarian concern. Refugee movements expose individuals to dire living conditions with severe inaccessibility to essential resources. Humanitarian organizations play a vital role in alleviating these hardships through relief aid interventions. This study aims to optimize the fulfillment of recurring needs for geographically dispersed refugee groups en route to safe destinations. Here, capacitated mobile facilities are tasked with delivering relief aid to refugee groups periodically to ensure equitable service frequency. We formulate the problem as a Markov decision process with multinomial state-transition distributions, shaped by external migration pull factors such as safety conditions, road accessibility, and spatial proximity. The objective is to minimize the relocation and replenishment costs of mobile facilities, along with the deprivation costs faced by underserved refugees. We develop an approximate dynamic programming algorithm featuring a novel policy replication routine. To complement this offline method, we introduce a state-dependent variable threshold policy that enables high-quality, real-time relief provision. Using instances inspired by the Syrian refugee crisis, our results demonstrate the substantial value of stochastic modeling, yielding a 25% reduction in expected total costs compared to deterministic baselines and up to 12% savings through coordinated planning among humanitarian actors. The proposed methods remain effective under dispersed and cohesive refugee group dynamics and multi-destination migration scenarios. Furthermore, we uncover high-frequency traversal and service hotspots along migration paths to provide tactical insights for parameter calibration and resource prepositioning. Collectively, our findings offer practical insights for managing ongoing and future refugee migration crises.TÜBİTA
