4653 research outputs found
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Multi-objective evolutionary optimization of photovoltaic glass for thermal, daylight, and energy consideration
No full textThe potential of fenestration systems is increased by incorporating photovoltaic technology into windows. This recently developed technology enhances the ability to generate energy from the building facade, improve the thermal and daylight performance of buildings, and visual comfort of occupants. Integrating an evolutionary optimization algorithm into this technology is one of the possible sustainable solutions to enhance building performance and minimize environmental impact. This paper uses a genetic evolutionary optimization algorithm to explore the optimum performance of photovoltaic glass in an architecture studio regarding annual energy consumption, energy generation, and daylight performance. Design variables include a window-to-wall ratio (i. e., window size and location) and amorphous-silicon thin-film solar cell transparency to generate optimum Pareto-front solutions for the case building. Optimization objectives are minimizing annual thermal (i.e., heating and cooling) loads and maximizing Spatial Daylight Autonomy. Optimized results of low-E semi-transparent amorphous-silicon photovoltaic glass applied on the facade show that the spatial daylight autonomy is increased to 82% with reduced glare risk and higher visual comfort for the occupants. Photovoltaic glass helped reduce the selected room's seasonal and annual lighting loads by up to 26.7%. Lastly, compared to non-optimized photovoltaic glass, they provide 23.2% more annual electrical energy.Energy & Fuel
Theory and Experiment of Spatial Light Modulation and Demodulation With Multi-Plane Diffraction and Applications
No full textSpatial light modulation enhances capacity of optical communications by modulating spatial amplitude, phase and polarization degrees of freedom with recent success of orbital angular momentum based architectures. There is a hardware challenge to demodulate large symbol families or high order symbols requiring a general design of spatial light demodulation. Multi-plane diffraction (MPD) recently introduced for improving spatial modulation capabilities in free space optical channels promises utilization at the receiver side as a demodulator. In this article, we theoretically model, numerically simulate and experimentally implement spatial light demodulation based on MPD. Numerical simulations and experimental implementations verify capabilities of MPD for increasing inter-symbol distances at the detector front-end. We obtain approximately two times improvement compared with direct detection for basic design including three diffraction planes as a proof-of-concept and improved performance with increasing number of diffraction planes compared with state-of-the-art single-plane diffraction (SPD) based interferometric receivers. Besides that, we perform, for the first time, experimental implementation of MPD based spatial light modulation. In addition, symmetric-key cryptography application of the proposed system is theoretically presented with low decoder complexity while numerical simulations promise high performance security against intruders. MPD based design is practically applicable and promising for diverse optical architectures including both communications and cryptography as a low-cost, low hardware complexity, passive and high performance design.Computer Science, Information Systems || Engineering, Electrical & Electronic || Telecommunication
Instagramming the Political Image: Visual Campaigning Strategies of Successful Opposition Candidates in Turkey's 2019 Mayoral Elections
No full textThis study explores how opposition political candidates strategically use Instagram images for their election campaigns in a competitive authoritarian regime. The article focuses on Turkey's 2019 mayoral elections and reports findings from 452 Instagram posts by the winning candidates in the three biggest cities (Izmir, Ankara, and Istanbul), all of whom are from the opposition, the Republican People's Party (CHP). The results from a quantitative content analysis show that all elected mayors mainly applied their traditional media strategies directly to Instagram as part of broadcasting purposes. They rarely extended their campaigning to other media platforms as part of a hybrid campaign strategy. Implications of the role of Instagram in challenging incumbent parties in competitive authoritarian regimes are discussed.Communicatio
The Association between Meteorological Drought and the State of the Groundwater Level in Bursa, Turkey
No full textThis study addressed the intricate interplay between meteorological droughts and groundwater level fluctuations in the vicinity of Mount Uludag in Bursa, Turkey. To achieve this, an exhaustive analysis encompassing monthly precipitation records and groundwater level data sourced from three meteorological stations and eight groundwater observation points spanning the period from 2007 to 2018 was performed. Subsequently, this study employed the Standard Precipitation Index (SPI) and Standard Groundwater Level (SGL) metrics, meticulously calculating the temporal extents of drought events for each respective time series. Following this, a judicious application of both the Thiessen and Support Vector Machine (SVM) methodologies was undertaken to ascertain the optimal groundwater observation wells and their corresponding SGL durations, aligning them with SPI durations tied to the selected meteorological stations. The SVM technique, in particular, excelled in the identification of the most pertinent observation wells. Additionally, the Elman Neural Network (ENN) and its optimized version through the Firefly Algorithm (ENN-FA), demonstrated their prowess in accurately predicting SPI durations based on SGL durations. The results were favorable, as evidenced by the commendable performance metrics of the Normalized Root Mean Square Error (NRMSE), the Nash-Sutcliffe Efficiency (NSE), the product of the coefficient of determination and the slope of the regression line (bR2), and the Kling-Gupta Efficiency (KGE). Consequently, the favorable simulation results were construed as evidence supporting the presence of a discernible association between SGL and the duration of the SPI. As we substantiate the concordance between the temporal extent of meteorological droughts and the perturbations in groundwater levels, this unmistakably underscores the fact that the historical fluctuations in groundwater levels within the region were predominantly attributable to climatic influences, rather than being instigated by anthropogenic activities. Nevertheless, it is imperative to underscore that this revelation should not be misconstrued as an endorsement of future heedless exploitation of groundwater resources.Green & Sustainable Science & Technology || Environmental Sciences || Environmental Studie
Three stories of one truth? Visual framing of AP, CNN & FOX news Instagram coverage of the 2020 US presidential candidates
No full textFraming bias was suggested in earlier research and media outlets have been accused of partisan tendencies in accordance with the political leanings they are supposedly associated with in popular imagination. The 2008 election cycle presented compelling evidence for the influence wielded by social media platforms in political communication, thereby establishing them as critical tools for candidates' electoral campaigns. The consequential role played by these digital platforms in electioneering has been increasingly recognized in the years since, cementing their centrality to contemporary political journalism. Instagram is one such medium for distributing news. The visual platform provides news media outlets with the ability to distribute their content produced in non-native formats not original to the platform. This predominant visual approach is ideal for political news coverage and the visual framing of the presidential candidates by the media. This study looks for differences in visual framing of 2020 US presidential candidates, Joe Biden, and Donald Trump, through the analysis of pictures posted on the Instagram accounts of the Associated Press, CNN, and Fox News to identify any partisan tendencies in their choices of images. No evidence was found of any substantial partisan tendencies in terms of frame choices in all three mainstream news outlets. Nevertheless, the findings from a two-sample test of proportions indicate that Fox News demonstrated a statistically significant bias towards Trump in terms of the number of frames allocated to him in comparison to Biden during their coverage. Implications of the findings for visual political communication are discussed.Humanities, Multidisciplinar
Market segmentation and international diversification across country and industry portfolios
No full textWe conjecture that partially segmented stock indexes that are characterized by low correlation with the world market are mainly priced by local factors and should produce abnormal returns relative to a global asset-pricing model. This implies a negative relation between correlation and future index returns in the presence of segmented indexes. Empirical evidence confirms such a relationship for the sample of industry indexes, suggesting a heterogeneous segmentation. However, we do not observe a similar pattern for country indexes. In addition, the international diversification potential of industries does not vanish during volatile periods. The hypothesis that the negative relationship should be stronger for the more segmented subsamples that are char-acterized by small market size and emerging country origin is verified for the industry sample. Thus, cross-industry diversification is superior to mere cross-country diversification.Business, Financ
Production and energy mode control of a production-inventory system
No full textEnergy efficiency in manufacturing can be improved by controlling energy modes and production dy-namically. We examine a production-inventory system that can operate in Working, Idle, and Off energy modes with mode-dependent energy costs. There can be a warm-up delay to switch between one mode to another. With random inter-arrival, production and warm-up times, we formulate the problem of de-termining in which mode the production resource should operate at a given time depending on the state of the system as a stochastic control problem under the long-run average profit criterion considering the sales revenue together with energy, inventory holding and backlog costs. The optimal solution of the problem for the exponential inter-arrival, production and warm-up times is determined by solving the Markov Decision Process with a linear programming approach. The structure of the optimal policy for the exponential case uses two thresholds to switch between the Working and Idle or Working and Off modes. We use the two-threshold policy as an approximate policy to control a system with correlated inter-event times with general distributions. This system is modelled as a Quasi Birth and Death Process and analyzed by using a matrix-geometric method. Our numerical experiments show that the joint pro-duction and energy control policy performs better compared to the pure production and energy control policies depending on the system parameters. In summary, we propose a joint energy and production control policy that improves energy efficiency by controlling the energy modes depending on the state of the system. (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )Management || Operations Research & Management Scienc
Changing Attitudes Towards Water Consumption: Influencer Communication on Instagram
No full textDue to environmental challenges, water scarcity has become a global issue, and consumers' water conservation attitudes (WCA) have become crucial. Although traditional media campaigns have a power on consumers' motivation to change their sustainable water consumption behaviours, social media campaigns can be more influential in changing negative attitudes into positive ones toward water conservation. Influencer marketing can especially cause changes in a shorter time since it provides more personal communication than traditional marketing communication. This study aims to reveal whether influencer marketing can change water consumption attitudes (WCA). The main research question is: Does influencer communication about water conservation cause an attitude change in the followers? We conducted a quasi-experimental design for three weeks and examined consumers' WCA by pre-and post-test results by using the WCA survey developed by Dolnicar & Hurlimann [1]. Participants answered the survey before and after being exposed to the 24 videos shared by the influencer. The increase in attitude points is statistically significant (t= -15.461, p=.000).Water Resource
Remembering Cinematic Sequences: Boundaries Disrupt Memory in High Paced Visual Events
No full textPsychology, Multidisciplinar
Redesigning for Disassembly and Carbon Footprint Reduction: Shifting from Reinforced Concrete to Hybrid Timber-Steel Multi-Story Building
No full textTo reduce carbon emissions, holistic approaches to design, plan, and build our environment are needed. Regarding multi-story residential buildings, it is well-known that (1) material choices and construction typologies play a fundamental role in the reduction of carbon footprint, (2) shifting from concrete to timber will reduce significantly the carbon footprint, and (3) a building designed to be disassembled will increase the potential of achieving zero-carbon emissions. However, little has been said about the consequences of such shifts and decisions in terms of building architecture and structural design, especially in seismic-prone regions. In this study, an existing 9-story reinforced concrete (RC) multi-story residential building is redesigned with cross-laminated timber floors and glue-laminated timber frames for embodied carbon reduction purposes. Firstly, the reasons behind design decisions are addressed in terms of both architecture and structure, including the incorporation of specially steel concentrically braced frames for seismic-resistance. Then, the outcomes of life cycle assessments and pushover analyses show that the RC residential building emits two times more carbon than the hybrid steel-timber residential building, and that while the hybrid building's lateral load-capacity is less than in the RC building, its deformation capacity is higher. These results highlight the relevance of considering the carbon footprint in combination with the design decisions, which seems to be the key to introducing circular projects in seismic-prone areas.Green & Sustainable Science & Technology || Environmental Sciences || Environmental Studie