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Full-Text Articles in Physical Sciences and Mathematics

Formulation And Implementation Of Iterative Method For Generating Spatially-Variant Lattices, Manuel Fernando Martinez Jan 2019

Formulation And Implementation Of Iterative Method For Generating Spatially-Variant Lattices, Manuel Fernando Martinez

Open Access Theses & Dissertations

The use of a matrix-free, memory-efficient approach to generate large-scale spatially variant lattices (SVL) was explored. A matrix-free iterative SVL generation algorithm was formulated and then implemented with a tremendous memory reduction observed. The algorithm consists of solving first-order central finite-differences along the entirety of the problem space point-by-point to obtain the grating phase function Φ(𝑠⃗) to which all desired spatially variant lattice properties are applied to. The algorithm was studied to identify key areas of data and task parallelism to exploit in heterogeneous computing systems consisting of clusters of central processing units (CPU) and graphics processing units (GPU) combinations. …


Synthesis, Characterization And Antibacterial Properties Of Silver(I) N-(4-Pyridyl) Benzamide Complexes With Varying Conterions, Mauro J. Ruiz Jan 2019

Synthesis, Characterization And Antibacterial Properties Of Silver(I) N-(4-Pyridyl) Benzamide Complexes With Varying Conterions, Mauro J. Ruiz

Open Access Theses & Dissertations

Organic semiconductor materials composed of - stacking aromatic compounds have been under intense investigation for their potential uses in flexible electronics and other advanced technologies. Herein we report a new family of seven - stacking compounds of Silver(I) N-(4-pyridyl) Benzamide with varying counterions, namely [Ag(NPBA)2]X, where NPBA is N-(4-pyridyl) Benzamine, X = NO3- (1), ClO4- (2), CF3SO3- (3), PF6- (4), BF4- (5), CH3PhSO3- (6), and PhSO3- (7), which form extended - stacking networks in one-dimensional (1D), 2D and 3D directions in the crystalline solid-state via the phenyl moiety, with average inter-ring distances of 3.823 Å. Interestingly, the counterions that contain …


Recent Results From Nb₃Sn Single Cell Cavities Coated At Jefferson Lab, U. Pudasaini, M. J. Kelley, Gianluigi Ciovati, G.V. Eremeev, M. J. Kelley, C. E. Reece, Ishwari Prasad Parajuli, Md. Nizam Sayeed Jan 2019

Recent Results From Nb₃Sn Single Cell Cavities Coated At Jefferson Lab, U. Pudasaini, M. J. Kelley, Gianluigi Ciovati, G.V. Eremeev, M. J. Kelley, C. E. Reece, Ishwari Prasad Parajuli, Md. Nizam Sayeed

Physics Faculty Publications

Because of superior superconducting properties (Tc ~ 18.3K, Hs h~ 425 mT and Δ ~ 3.1 meV) compared to niobium, Nb₃Sn promise better RF performance (Q₀ and Eacc) and/or higher operating temperature (2 K Vs 4.2 K) for SRF cavities. Nb₃Sn-coated SRF cavities are produced routinely by depositing a few micron-thick Nb₃Sn films on the interior surface of Nb cavities via tin vapor diffusion technique. Early results from Nb₃Sn cavities coated with this technique exhibited precipitous low field Q-slope, also known as Wuppertal slope. Several Nb₃Sn single cell cavities coated at JLab appeared to exhibit …


Fast Nonsingular Terminal Decoupled Sliding-Mode Control Utilizing Time-Varying Sliding Surfaces, Ferhun Yorgancioğlu, Soydan Redif Jan 2019

Fast Nonsingular Terminal Decoupled Sliding-Mode Control Utilizing Time-Varying Sliding Surfaces, Ferhun Yorgancioğlu, Soydan Redif

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a fast form of nonsingular, terminal, decoupled, sliding-mode control, which utilizes time-varying sliding surfaces, is proposed for a class of fourth-order, single-input, multioutput, nonlinear systems. The novel control law features a fast term, in the manner of fast terminal sliding-mode control, which markedly improves the finite-time sliding-mode convergence speed near zero. Numerical simulation results, which are illustrated with a cart-pole inverted pendulum system and a ball-beam system, demonstrate that the proposed control law achieves, in general, favorable transient response and lower steady-state errors compared to state-of-the-art decoupled terminal sliding-mode control methods.


A Novel Resource Clustering Model To Develop An Efficient Wireless Personal Cloud Environment, Kowsigan Mohan, Balasubramanie Palanisamy Jan 2019

A Novel Resource Clustering Model To Develop An Efficient Wireless Personal Cloud Environment, Kowsigan Mohan, Balasubramanie Palanisamy

Turkish Journal of Electrical Engineering and Computer Sciences

In the current era, cloud computing is the major focus of distributed computing and it helps in satisfying the requirements of the business world. It provides facilities on demand under all the parameters of the computing, such as infrastructure, platform, and software, across the globe. One of the major challenges in the cloud environment is to cluster the resources and schedule the jobs among the resource clusters. Many existing approaches failed to provide an optimal solution for job scheduling due to inefficient clustering of resources. In the proposed system, a novel algorithm called resource differentiation based on equivalence node potential …


Optimal Rescheduling Of Real Power To Mitigate Congestion Using Gravitational Search Algorithm, Kaushik Paul, Niranjan Kumar, Shaligram Agrawal, Kamalendu Paul Jan 2019

Optimal Rescheduling Of Real Power To Mitigate Congestion Using Gravitational Search Algorithm, Kaushik Paul, Niranjan Kumar, Shaligram Agrawal, Kamalendu Paul

Turkish Journal of Electrical Engineering and Computer Sciences

The initiative to manage congestion has gained interest in the current deregulated scenario. The principle commitment of the work in this article is to extend the gravitational search algorithm (GSA) as an efficient metaheuristic optimizing algorithm to diminish the rescheduling cost and efficiently attenuate the overloading of the line with the minimal deviation in the active power generation. The congestion management drive is accomplished by prioritizing the generators based on their sensitivity values. Thereafter, the GSA is introduced to optimally minimize the rescheduling cost along with the minimization of the total amount of active power output and system losses. The …


Design Of A Range-Segmented Cmos Current-Mode Exponential Circuit, Chih-Jen Cheng, Kuo-Jen Lin, Jwu-E Chen Jan 2019

Design Of A Range-Segmented Cmos Current-Mode Exponential Circuit, Chih-Jen Cheng, Kuo-Jen Lin, Jwu-E Chen

Turkish Journal of Electrical Engineering and Computer Sciences

A CMOS current-mode exponential circuit is designed by plugging candidate circuits into a Taylor's approximation circuit to make a multiple-segment circuit. The selection of candidate circuits is dependent on a large linearity range in each segment. The proposed range-segmented circuit is different from all segments constructed only by quadratic circuits or only by linear circuits. The proposed circuit was simulated using UMC 0.18~$\mu$m CMOS technology. The output linearity of the circuit is 56.7~dB for gain error less than 0.5~dB, and the --3~dB bandwidth of the circuit is between 69 and 150~MHz for input range from --63 to 198~$\mu$A.


Low-Cost Multimode Diode-Pumped Tm:Yag And Tm:Luag Lasers, Ersen Beyatli Jan 2019

Low-Cost Multimode Diode-Pumped Tm:Yag And Tm:Luag Lasers, Ersen Beyatli

Turkish Journal of Electrical Engineering and Computer Sciences

We report a continuous-wave operation of Tm:YAG and Tm:LuAG lasers pumped with a low-cost, multimode AlGaAs laser diode. First, the lifetime and the absorbance behavior of 5 mm, 6 % Tm$^{3+}$-doped YAG and LuAG crystals were thoroughly investigated. A low-cost multimode 3W laser diode at 781 nm was then used as a pump source for the Tm$^{3+}$-doped laser systems. Using three different output couplers, up to 636 mW of output power was obtained from Tm:YAG laser, with a slope efficiency of 29 % at 2017 nm. The maximum output power was 637 mW in the Tm:LuAG laser, with a slope …


A Smart Wireless Sensor Network Node For Fire Detection, Wajahat Khalid, Asma Sattar, Muhammad Ali Qureshi, Asjad Amin, Mobeen Ahmed Malik, Kashif Hussain Jan 2019

A Smart Wireless Sensor Network Node For Fire Detection, Wajahat Khalid, Asma Sattar, Muhammad Ali Qureshi, Asjad Amin, Mobeen Ahmed Malik, Kashif Hussain

Turkish Journal of Electrical Engineering and Computer Sciences

Fires generally occur due to human carelessness and the change in environmental conditions. The uncontrolled fire results in death incidents of humans and animals as well as severe threats to the ecosystem. The preservation of the natural environment is important. The wireless sensor networks, widely used in different monitoring applications, is used in this work. For fire detection, we use flame, smoke, temperature, humidity, and light intensity sensors in our proposed network node which is low-cost, reduced-size, and power-efficient. The experiments are performed in a well-controlled real-time environment. The proposed node transmits the sensed data to the central node. The …


Optimal Dg Allocation For Enhancing Voltage Stability And Minimizing Power Loss Using Hybrid Gray Wolf Optimizer, Salah Kamel, Ayman Awad, Hussein Abdel-Mawgoud, Francisco Jurado Jan 2019

Optimal Dg Allocation For Enhancing Voltage Stability And Minimizing Power Loss Using Hybrid Gray Wolf Optimizer, Salah Kamel, Ayman Awad, Hussein Abdel-Mawgoud, Francisco Jurado

Turkish Journal of Electrical Engineering and Computer Sciences

High penetration of photovoltaic and wind turbine-based distributed generators (DGs) can help reduce carbon emissions which is an important goal for the whole world. DG can be used to improve the voltage stability, present generation reserve/emergency, and consequently, the system power quality can be improved. However, it is very important to select the right size and location of a DG so that the power system can increase the gained benefits of such an installation to the maximum. In this paper, a hybrid optimization technique is proposed to determine the optimal allocation of DG in the standard IEEE 33-bus radial distribution …


Method Of Limiting The Emissivity Of Wsn Networks, Tomasz Marciniak, Slawomir Bujnowski, Beata Marciniak, Zbigniew Lutowski Jan 2019

Method Of Limiting The Emissivity Of Wsn Networks, Tomasz Marciniak, Slawomir Bujnowski, Beata Marciniak, Zbigniew Lutowski

Turkish Journal of Electrical Engineering and Computer Sciences

Wireless sensor networks (WSNs) are a current topic of research that find usage in many applications from environmental monitoring and health protection to military applications. In this paper, analysis of the possibility of reducing the emissivity of radio sensor networks with the assumed transmission probability is discussed. This has a direct influence on power consumption by the nodes and network lifetime. A method based on introducing retransmissions on individual links creating paths between the nodes is presented. Two approaches are used in analyses, the first one being deterministic methods and the second one simulation. Both methods are used to determine …


Reusable And Interactive Classes: A New Way Of Object Composition, Saeid Masoumi, Ali Mahjur Jan 2019

Reusable And Interactive Classes: A New Way Of Object Composition, Saeid Masoumi, Ali Mahjur

Turkish Journal of Electrical Engineering and Computer Sciences

Separating object features from base classes is one of the popular ways of software development. Some popular programming approaches like object-oriented programming, feature-oriented programming, and aspect-oriented programming follow this approach. There are four advantages of using features: 1) Instantiability: the ability to create instances of a feature, 2) Reusability: the quality of a feature being reusable in many compositions, 3) Loosely coupled composability: the ability to compose/decompose features easily at object instantiation time (not offering new data types for compositions), and 4) Interactability: the ability of a feature to crosscut (interact with) other features inside the object. Existing approaches do …


Speech Emotion Recognition Using Semi-Nmf Feature Optimization, Surekha Reddy Bandela, T Kishore Kumar Jan 2019

Speech Emotion Recognition Using Semi-Nmf Feature Optimization, Surekha Reddy Bandela, T Kishore Kumar

Turkish Journal of Electrical Engineering and Computer Sciences

In recent times, much research is progressing forward in the field of speech emotion recognition (SER). Many SER systems have been developed by combining different speech features to improve their performances. As a result, the complexity of the classifier increases to train this huge feature set. Additionally, some of the features could be irrelevant in emotion detection and this leads to a decrease in the emotion recognition accuracy. To overcome this drawback, feature optimization can be performed on the feature sets to obtain the most desirable emotional feature set before classifying the features. In this paper, semi-nonnegative matrix factorization (semi-NMF) …


Evaluating The Attributes Of Remote Sensing Image Pixels For Fast K-Means Clustering, Ali̇ Sağlam, Nurdan Baykan Jan 2019

Evaluating The Attributes Of Remote Sensing Image Pixels For Fast K-Means Clustering, Ali̇ Sağlam, Nurdan Baykan

Turkish Journal of Electrical Engineering and Computer Sciences

Clustering process is an important stage for many data mining applications. In this process, data elements are grouped according to their similarities. One of the most known clustering algorithms is the k-means algorithm. The algorithm initially requires the number of clusters as a parameter and runs iteratively. Many remote sensing image processing applications usually need the clustering stage like many image processing applications. Remote sensing images provide more information about the environments with the development of the multispectral sensor and laser technologies. In the dataset used in this paper, the infrared (IR) and the digital surface maps (DSM) are also …


A Crowdsensing-Based Framework For Urban Air Quality Decision Support, Hasna Elalaoui Elabdallaoui, Abdelaziz Elfazziki, Jamal Ouarzazi, Fatima Zohra Ennaji, Mohamed Sadgal Jan 2019

A Crowdsensing-Based Framework For Urban Air Quality Decision Support, Hasna Elalaoui Elabdallaoui, Abdelaziz Elfazziki, Jamal Ouarzazi, Fatima Zohra Ennaji, Mohamed Sadgal

Turkish Journal of Electrical Engineering and Computer Sciences

Air pollution is considered a major health problem in urban areas. Small sensor technology integrated with smart phones can be widely used to collect air quality information in real time using mobile applications. By applying the concept of crowdsensing, citizens and authorities can be aware of exposure to pollution during their daily activities in urban areas. This paper describes an on-road air quality monitoring and control approach based on the crowdsensing paradigm. In addition to collecting air pollution data, we are exploring the possibility of using this technology to effectively detect critical situations and redistribute all information through a proactive …


Rough Fuzzy Cuckoo Search For Triclustering Microarray Gene Expression Data, Swathypriyadharsini Palaniswamy, Premalatha K Jan 2019

Rough Fuzzy Cuckoo Search For Triclustering Microarray Gene Expression Data, Swathypriyadharsini Palaniswamy, Premalatha K

Turkish Journal of Electrical Engineering and Computer Sciences

Analyzing time series microarray gene expression data is a computational challenge due to its three-dimensional characteristics. Triclustering techniques are applied to three-dimensional data for mining similarly expressed genes under a subset of conditions and time points. In this work, a novel rough fuzzy cuckoo search algorithm is proposed for triclustering genes across samples and time points simultaneously. By applying the upper and lower approximation of rough set theory and the objective function of fuzzy k-means, rough fuzzy k-means was incorporated into a cuckoo search to handle the uncertainty of the data. The proposed method was applied to three real-life time …


Performance Evaluation Of Webrtc-Based Online Consultation Platform, Ergün Alperay Tarim, Hüseyi̇n Cumhur Teki̇n Jan 2019

Performance Evaluation Of Webrtc-Based Online Consultation Platform, Ergün Alperay Tarim, Hüseyi̇n Cumhur Teki̇n

Turkish Journal of Electrical Engineering and Computer Sciences

Information technologies give patients the opportunity to communicate with medical professionals remotely. Telemedicine uses these technologies to provide advanced healthcare and medical services. We present a medical online consultation application based on Web Real-Time Communications (WebRTC) technology enabling chat, audio, and video calls. Communication architecture and protocols of the application are explained in detail. Additionally, the user interface of the application is shown via performed calls. The application is tested and evaluated on different network connections (3G, 4G, local, and DSL) and different browsers and mobile operating systems (Android, Chrome, Firefox, Internet Explorer, iOS, Opera, Safari). During calls, communication quality …


On The Output Regulation For Linear Fractional Systems, Jesus Alberto Meda Campana, Elba Cinthya Garcia Estrada, Julio Cesar Gomez Mancilla, Jose De Jesus Rubio Avila, Mario Ricardo Cruz Deviana, Ricardo Tapia Herrera Jan 2019

On The Output Regulation For Linear Fractional Systems, Jesus Alberto Meda Campana, Elba Cinthya Garcia Estrada, Julio Cesar Gomez Mancilla, Jose De Jesus Rubio Avila, Mario Ricardo Cruz Deviana, Ricardo Tapia Herrera

Turkish Journal of Electrical Engineering and Computer Sciences

In this work, the regulation problem is extended to the field of fractional-order linear systems considering the Caputo fractional derivative. The regulation equations are obtained on the basis of the Francis equations. It is also shown that the linear fractional regulator exists at $t=0$ only if the order of the plant is not greater than the order of the reference system.


Adaptive Iir Filter Design Using Self-Adaptive Search Equation Based Artificial Bee Colony Algorithm, Burhanetti̇n Durmuş, Gürcan Yavuz, Doğan Aydin Jan 2019

Adaptive Iir Filter Design Using Self-Adaptive Search Equation Based Artificial Bee Colony Algorithm, Burhanetti̇n Durmuş, Gürcan Yavuz, Doğan Aydin

Turkish Journal of Electrical Engineering and Computer Sciences

Infinite impulse response (IIR) system identification problem is defined as an IIR filter modeling to represent an unknown system. During a modeling task, unknown system parameters are estimated by metaheuristic algorithms through the IIR filter. This work deals with the self-adaptive search-equation-based artificial bee colony (SSEABC) algorithm that is adapted to optimal IIR filter design. SSEABC algorithm is a recent and improved variant of artificial bee colony (ABC) algorithm in which appropriate search equation is determined with a self-adaptive strategy. Moreover, the success of the SSEABC algorithm enhanced with a competitive local search selection strategy was proved on benchmark functions …


Improving Side Lobe Level Of X-Band Microstrip Rotman Lens Utilizing Nonuniform Distribution Of Output Ports, Ehsan Zareian Jahromi, Raheleh Basiri, Parvin Salehi, Hamidreza Karami Jan 2019

Improving Side Lobe Level Of X-Band Microstrip Rotman Lens Utilizing Nonuniform Distribution Of Output Ports, Ehsan Zareian Jahromi, Raheleh Basiri, Parvin Salehi, Hamidreza Karami

Turkish Journal of Electrical Engineering and Computer Sciences

A new microstrip Rotman lens with enhanced side lobe level (SLL) is proposed for X-band applications. A proper nonuniform distribution of the initial width of output ports is considered to improve the SLL. The benefit of SLL improvement is not based on using additional attenuators or amplifiers at the output ports. Moreover, an analytical background is presented to investigate the resulting SLL of the proposed structure. The advantage of SLL enhancement is obtained at all noncorner scan angles considering 10 GHz operating frequency. As the middle input port is excited, more than 3 dB of SLL enhancement is achieved at …


A Novel And Unified Approach For Averaged Channel Capacity And Averagedeffective Capacity Analyses Of Diversity Combining And Multihop Transmissionschemes In Flat Fading Environments, Ferkan Yilmaz, Mohamed-Slim Alouini Jan 2019

A Novel And Unified Approach For Averaged Channel Capacity And Averagedeffective Capacity Analyses Of Diversity Combining And Multihop Transmissionschemes In Flat Fading Environments, Ferkan Yilmaz, Mohamed-Slim Alouini

Turkish Journal of Electrical Engineering and Computer Sciences

n this paper, we introduce an Lp -norm aggregation to present a signal-to-noise ratio expression unified not only for such diversity combining schemes as equal-gain combining, maximal-ratio combining, and selection combining, but also for such transmission techniques as multihop transmission. Accordingly, we propose two moment-generating function-based approaches that both respectively unify the exact analyses of the averaged channel capacity and averaged effective capacity over generalized fading channels with respect to the diversity combining and multihop transmission schemes. Finally, the mathematical formalism is illustrated by numerical special cases and verified by simulations.


Determination Of Distance Between Dc Traction Power Centers In A 1500-V Dc Subway Line With Artificial Intelligence Methods, Mehmet Taci̇ddi̇n Akçay, İlhan Kocaarslan Jan 2019

Determination Of Distance Between Dc Traction Power Centers In A 1500-V Dc Subway Line With Artificial Intelligence Methods, Mehmet Taci̇ddi̇n Akçay, İlhan Kocaarslan

Turkish Journal of Electrical Engineering and Computer Sciences

The electrification system in rail systems is designed with regard to the operating data and design parameters. While the electrification system is formed, the minimum voltage rating that the traction force requires during the operation needs to be provided. The highest value of the voltage drop occurring on the line is determined by the distance between power centers. This value needs to be kept within certain limits for the continuity of operation. In this study, the determination of the distance between DC traction power centers for a 1500-V DC-fed rail system is done by means of the adaptive neuro-fuzzy inference …


A Coordinated Dc Voltage Control Strategy For Cascaded Solid State Transformer With Star Configuration, Zhendong Ji, Yichao Sun, Cheng Jin, Jianhua Wang, Jianfeng Zhao Jan 2019

A Coordinated Dc Voltage Control Strategy For Cascaded Solid State Transformer With Star Configuration, Zhendong Ji, Yichao Sun, Cheng Jin, Jianhua Wang, Jianfeng Zhao

Turkish Journal of Electrical Engineering and Computer Sciences

Cascaded solid-state transformer (SST) can be directly connected to the high-voltage distribution grid, and it has broad applications in the future smart grid, traction locomotive, and renewable energy integration. However, the reliability of the cascaded SST is seriously influenced by the DC voltage and power imbalance issues with this configuration. This paper presents a coordinated DC voltage control strategy for cascaded SST with star configuration, in which the average DC voltage and the balancing DC voltage are controlled separately without current sensors in dual active bridge (DAB) modules. This strategy not only reduces the cost and the complexity of the …


Approximation Of Planar Curves, Malik Zawwar Hussain, Ayesha Shakeel, Maria Hussain Jan 2019

Approximation Of Planar Curves, Malik Zawwar Hussain, Ayesha Shakeel, Maria Hussain

Turkish Journal of Electrical Engineering and Computer Sciences

In the present article, we have developed the $G^{2}$-approximation scheme for planar curves arising in science, engineering, computer-aided design, computer-aided manufacturing, and many other fields. The obtained results reveal that the proposed method is a significant addition to the approximation of planar curves. The method is illustrated using different numerical examples. The smaller absolute error confirms the applicability and efficiency of the proposed method.


Cost-Effective Telemetry For Energy Network Of An Electricity Distribution Company: Part I, Asim Zaheer Ud Din, Yasar Ayaz, Mian Ilyas Ahmad Ahmad, Momena Hasan, Salman Masaud, Naveed Muhammad Jan 2019

Cost-Effective Telemetry For Energy Network Of An Electricity Distribution Company: Part I, Asim Zaheer Ud Din, Yasar Ayaz, Mian Ilyas Ahmad Ahmad, Momena Hasan, Salman Masaud, Naveed Muhammad

Turkish Journal of Electrical Engineering and Computer Sciences

We present a novel application of radio frequency wireless mesh network and general packet radio service technologies in a telemetry solution to measure power flow in the energy network of an electricity distribution company. The telemetry solution utilizes some selected circuits of grid stations and calculates total power consumed, total power imported, and total power exported by the distribution company. The selection of circuits for sensors installation is the key for reducing solution cost as compared to the case when sensors are installed on all the power output points. The framework involves installation of specially developed energy sensors (smart energy …


Understanding Attribute And Social Circle Correlation In Social Networks, Pranav Nerurkar, Madhav Chandane, Sunil Bhirud Jan 2019

Understanding Attribute And Social Circle Correlation In Social Networks, Pranav Nerurkar, Madhav Chandane, Sunil Bhirud

Turkish Journal of Electrical Engineering and Computer Sciences

Social circles, groups, lists, etc. are functionalities that allow users of online social network (OSN) platforms to manually organize their social media contacts. However, this facility provided by OSNs has not received appreciation from users due to the tedious nature of the task of organizing the ones that are only contacted periodically. In view of the numerous benefits of this functionality, it may be advantageous to investigate measures that lead to enhancements in its efficacy by allowing for automatic creation of customized groups of users (social circles, groups, lists, etc). The field of study for this purpose, i.e. creating coarse-grained …


Computational Imaging Systems For High-Speed, Adaptive Sensing Applications, Yangyang Sun Jan 2019

Computational Imaging Systems For High-Speed, Adaptive Sensing Applications, Yangyang Sun

Electronic Theses and Dissertations

Driven by the advances in signal processing and ubiquitous availability of high-speed low-cost computing resources over the past decade, computational imaging has seen the growing interest. Improvements on spatial, temporal, and spectral resolutions have been made with novel designs of imaging systems and optimization methods. However, there are two limitations in computational imaging. 1), Computational imaging requires full knowledge and representation of the imaging system called the forward model to reconstruct the object of interest. This limits the applications in the systems with a parameterized unknown forward model such as range imaging systems. 2), the regularization in the optimization process …


Design And Fabrication Of Scalable Multifunctional Multimaterial Fibers And Textiles, Felix Tan Jan 2019

Design And Fabrication Of Scalable Multifunctional Multimaterial Fibers And Textiles, Felix Tan

Electronic Theses and Dissertations

Multimaterial fibers eschew the traditional mono-material structures typical of traditional optical fibers for novel internal architectures that combine disparate materials with distinct optical, mechanical, and electronic properties, thereby enabling novel optoelectronic functionalities delivered in the form factor of an extended fiber. This new class of fibers developed over the past two decades is attracting interest from researchers in such different fields as optics, textiles, and biomedicine. The juxtaposition of multiple materials integrated at micro- and nanoscales in complex geometries while ensuring intimate smooth interfaces extending continuously for kilometers facilitates unique applications such as non-invasive laser surgery, self-monitoring fibers, e-textiles, and …


Stable, Highly Luminescent Perovskite-Polymer Composites For Photonics Applications, Juan He Jan 2019

Stable, Highly Luminescent Perovskite-Polymer Composites For Photonics Applications, Juan He

Electronic Theses and Dissertations

Metal halide perovskites (simplified as perovskites as below), particularly those in nanocrystal forms, have recently emerged as highly efficient, bandgap tunable photonics materials that can be easily solution processed at low cost for display, lighting or other energy conversion applications. However, the quick degradation of perovskite nanocrystals under external stresses or upon colloidal aggregations has been a major challenge for most applications where high reliability is normally required. In this thesis, we have explored a polymer swelling-deswelling microencapsulation (SDM) process that enables the dispersion, in-situ crystallization and subsequent surface passivation of perovskite nanocrystals in polymer matrices, and leads to ultrastable …


Mode Coupling In Space-Division Multiplexed Systems, Huiyuan Liu Jan 2019

Mode Coupling In Space-Division Multiplexed Systems, Huiyuan Liu

Electronic Theses and Dissertations

Even though fiber-optic communication systems have been engineered to nearly approach the Shannon capacity limit, they still cannot meet the exponentially-growing bandwidth demand of the Internet. Space-division multiplexing (SDM) has attracted considerable attention in recent years due to its potential to address this capacity crunch. In SDM, the transmission channels support more than one spatial mode, each of which can provide the same capacity as a single-mode fiber. To make SDM practical, crosstalk among modes must be effectively managed. This dissertation presents three techniques for crosstalk management for SDM. In some cases such as intra-datacenter interconnects, even though mode crosstalk …