An information theory based behavioral model for agent-based crowd simulations

Crowds must be simulated believable in terms of their appearance and behavior to improve a virtual environment’s realism. Due to the complex nature of human behavior, realistic behavior of agents in crowd simulations is still a challenging problem. In this paper, we propose a novel behavioral model which builds analytical maps to control agents’ behavior adaptively with agent-crowd interaction formulations. We introduce information theoretical concepts to construct analytical maps automatically. Our model can be integrated into crowd simulators and enhance their behavioral complexity. We made comparative analyses of the presented behavior model with measured crowd data and two agent-based crowd simulators

Precise torque control for interior mounted permanent magnet synchronous motors with recursive least squares algorithm based parameter estimations

Interior mounted permanent magnet (IPM) machines have superior features comparing to their counterparts for electric vehicle traction applications. Having relatively higher efficiency, high torque and power densities, low torque ripple and not requirement of regular maintenance are among their superior features. It is widely known that the precise torque control in practical IPM drives highly relies on accurate knowledge of machine parameters viz, inductance values and magnetic flux linkage. These machine parameters vary significantly in real time operation depending on manufacturing tolerance, operating temperature, inductance saturation, load torque and so on. It is known that d-and q-axis inductances and magnetic flux linkage at the full load operation may be approximately 20%, 35% and 20%, respectively, lower than their actual values at no-load operation. It is also commonly known in the literature for traction applications that these variations (considering wide range operation) have much influence on both drive system efficiency and output torque production compared to other system nonlinearities such as stator resistance variation. It has been achieved in this paper that these parameters are estimated online with fairly high accuracies of each, utilizing recursive least squares (RLS) algorithm. The superiority of the proposed drive achieving considerably higher output torque (-28,7% of peak torque) is validated through extensive realistic simulations with nonlinear machine model of a 4.1 kW prototype IPM machine designed and manufactured for traction applications. Proposed strategy and its superiority among state-of-art drives are discussed in detail. (c) 2021 Karabuk University. Publishing services by Elsevier B.V

Comparison of Interior Mounted Permanent Magnet Synchronous Motor Drives with Sinusoidal, Third Harmonic Injection, and Space Vector Pulse Width Modulation Strategies with particular attention to Current Distortions and Torque Ripples

Interior Mounted Permanent Magnet Synchronous Motors (IPMs) have become popular in electric vehicle traction applications in recent years due to their superior features such as high efficiency and high power density compared to other machines. Therefore, development of IPM drive systems is an important research area. In this study, three different pulse width modulation (PWM) strategies commonly used in machine drives are compared extensively in IPM drives. Simulations have been carried out with optimum dq-axes currents based on demanded torque from the system, and hence, the simulated drives are efficiency-optimized. Sinusoidal pulse width modulation (SPWM), third harmonic injection pulse width modulation (THIPWM), and space vector pulse width modulation (SVPWM) strategies have been employed in the drives, and comparisons have been made by paying particular attention to the total harmonic distortion (THD) rates of phase currents and torque ripples. It has been validated through extensive simulations that the SVPWM strategy has less THD percentage for IPM drives than SPWM and THIPWM at wide operating points, and hence, the current and torque responses are better with smooth output torque. Simulation results also validate that the current distortions and torque ripples are the highest when SPWM strategy is adopted in the drives, and hence, the THIPWM strategy is superior to the SPWM. © 2023 Istanbul University. All rights reserved

Estimation of environmental lighting from human face for illumination of augmented reality scenes

In this thesis, we propose a method to solve a common problem in augmented reality domain; estimating light sources in an outdoor scene and lighting virtual objects accordingly. As a basis of our method we developed a framework based on estimation of environmental lighting from well defined objects, specifically human faces. The method is tuned for outdoor use, and the algorithm is further enhanced to illuminate virtual objects exposed to direct sunlight. In the first part of this thesis, we propose a novel lighting estimation technique where we assume a user is looking straight to mobile devices camera. This technique extracts information from input images to calculate possible light sources to pass to the rendering stage. In the second part of this thesis, we propose a lighting model which uses the output from our lighting estimation in order to make objects appear as they are lit correctly by the sun light. This model uses a mathematical technique called Spherical Harmonics Lighting for real-time realistic rendering

Currency crises theory : third generation models

Ankara : The Department of Economic and the Institute of Economics and Social Sciences of Bilkent University, 2009.Thesis (Master's) -- Bilkent University, 2009.Includes bibliographical references leaves 38-39.This thesis investigates third generation currency crisis literature and concludes that the 2001 Turkish currency crisis can be labeled as a third generation type crisis, despite having unique characteristics. According to the model of Eijffinger and Goderis (2007) which derives risk premium of the economy from the balance sheet structure of the corporate sector, higher domestic debt increases the probability of currency crisis, whereas higher foreign debt can either increase or decrease the probability of a currency crisis depending on the parameter values. This model has little explanatory power for the 2001 crisis, since the crisis predominantly arise from the maturity mismatch problem in the balance sheet of the financial sector, coupled with moral hazard problem driven by implicit government guarantees. In addition to these two issues which are examined by different strands of third generation currency crisis literature, Turkish crisis display distinctive characteristics such as the role of fragile fiscal deficit financing mechanism.Koç, EmreM.S

Advanced tunability of optical properties of CdS/ZnSe/ZnTe/CdSe multi-shell quantum dot by the band edge engineering

In this study, the advanced manipulability of wave functions in a type-II multi-shell hetero-nanostructure (MS-HNS) and the tunability of radiative exciton lifetime over a wide range with and/or without changing in transition energies has been demonstrated by the band edge engineering. For this purpose, the electronic and optical properties of exciton (X) and biexciton (XX) in a spherical CdS/ZnSe/ZnTe/CdSe HNS have been explored in detail. In the calculations, effects of all Coulombic interactions between the charges have been taken into account on the wave functions. Moreover, in the case of XX, the exchange-correlation potential between the same charged particles has also been considered. The results have been presented as a function of CdS core radius and ZnSe shell thickness and the probable physical reasons have been discussed in detail

An Overview to Cytokeratin Pattern of Cholesteatoma

Cholesteatoma is a destructive pathology characterized with progressive and chronic infiltration of keratinized squamous epithelium that can be seen the middle ear and mastoid regions of temporal bone. It has serious intra and extracranial complications which can be difficult to manage. Embryologic remnants of squamous epithelium, squamous metaplasia of middle ear epithelium, migration of epidermal cells from external ear canal and tympanic membrane and cell seeding because of middle ear surgery or trauma were all stated as causes of cholesteatoma. Cytokeratins are important markers of cell differentiation. The patterns of cytokeratin expression correlate well with the state of keratinocyte proliferation, migration and differentiation. These patterns are known to be affected during the formation of cholesteatoma. Increasing our knowledge about cytokeratin patterns may help us understand the unknown formation of cholesteatoma. In this review article, a literature survey was done about cytokeratin patterns of cholesteatoma

Sparse Reconstruction for Near-Field MIMO Radar Imaging Using Fast Multipole Method

Radar imaging using multiple input multiple output systems are becoming popular recently. These applications typically contain a sparse scene and the imaging system is challenged by the requirement of high quality real-time image reconstruction from under-sampled measurements via compressive sensing. In this paper, we deal with obtaining sparse solution to near- field radar imaging problems by developing efficient sparse reconstruction, which avoid storing and using large-scale sensing matrices. We demonstrate that the "fast multipole method" can be employed within sparse reconstruction algorithms to efficiently compute the sensing operator and its adjoint (backward) operator, hence improving the computation speed and memory usage, especially for large-scale 3-D imaging problems. For several near-field imaging scenarios including point scatterers and 2-D/3-D extended targets, the performances of sparse reconstruction algorithms are numerically tested in comparison with a classical solver. Furthermore, effectiveness of the fast multipole method and efficient reconstruction are illustrated in terms of memory requirement and processing time

Risk Tabanlı Deniz Ambulansı Tasarımı

Denizde, emniyeti en üst düzeye çıkarmak için risk faktörlerini modellemek ve risk tabanlı tasarım araçlarını kullanmak önemlidir. Emniyeti arttırmak ve müşteri taleplerini karşılamak için etkin risk modelleme teknikleri ve karar verme araçlarının geliştirilmesi ve uygulanması gerekmektedir. Bu çalışmada, mevcut bir deniz ambulans teknesi operasyon riskleri incelenmiş ve mevcut tekne risk tabanlı bir yaklaşımla yeniden tasarlanmıştır. Risk değerlendirmesi ve model tasarımında, Hata Türü ve Etki Analizi (FMEA) kullanılmış ve risk öncelik sayıları (RPNs) hesaplanmıştır. Bu çalışmadan elde edilen sonuçlar, deniz ambulans teknelerinin emniyetini arttırmaya ve potansiyel risklerin önlenmesine veya azaltılmasına katkıda bulunacaktır

Recent Advances in Health Biotechnology During Pandemic

The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which emerged in 2019, cut the epoch that will make profound fluctuates in the history of the world in social, economic, and scientific fields. Urgent needs in public health have brought with them innovative approaches, including diagnosis, prevention, and treatment. To exceed the coronavirus disease 2019 (COVID-19) pandemic, various scientific authorities in the world have procreated advances in real time polymerase chain reaction (RT-PCR) based diagnostic tests, rapid diagnostic kits, the development of vaccines for immunization, and the purposing pharmaceuticals for treatment. Diagnosis, treatment, and immunization approaches put for- ward by scientific communities are cross-fed from the accrued knowledge of multidisciplinary sciences in health biotechnology. So much so that the pandemic, urgently prioritized in the world, is not only viral infections but also has been the pulsion in the development of novel approaches in many fields such as diagnosis, treatment, translational medicine, virology, mi- crobiology, immunology, functional nano- and bio-materials, bioinformatics, molecular biol- ogy, genetics, tissue engineering, biomedical devices, and artificial intelligence technologies. In this review, the effects of the COVID-19 pandemic on the development of various scientific areas of health biotechnology are discussed