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2018

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Articles 1081 - 1110 of 1644

Full-Text Articles in Electrical and Computer Engineering

Walking Gait Measurement And Gait Parameters Extraction, Chenye Li Jan 2018

Walking Gait Measurement And Gait Parameters Extraction, Chenye Li

Honors Theses

A fourth generation walking gait measurement device has been designed to capture and analyze detailed gait and stride metrics which eventually provides a Fall-Risk Assessment score. Specifically, the device has been modified to fit the residential environment and the elderly consumers which is low-cost, user-friendly, and portable. The gait parameters would be obtained by the on-board gait analysis protocol. Through gait parameters people's falling risk can then be calculated so that people can be alerted to take precautionary measures before falling. Overall, the device has been made and demonstrated having better performance than its previous generations. The on-board gait analyzing …

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Deciphering The Rules Of Cell-To-Cell Coupling By Molecular Modeling And Simulation, Linda D. Lee Jan 2018

Deciphering The Rules Of Cell-To-Cell Coupling By Molecular Modeling And Simulation, Linda D. Lee

REU Final Reports

Intercellular communication is vital for quick adjustments and maintenance for cell function and development. Gap junctions are membranes channel proteins that enable this direct communication between adjacent cells throughout the body. The compatibility of connexins (Cx), which make up a gap junction, determines whether a gap junction can form. Though many studies show which connexins are compatible, the molecular basis is not known (Bai & Wang, 2014). Through computational modeling, we identify the residues that energetically contribute most favorably at the docking interface of homotypic and heterotypic combinations of Cx43, Cx46, and Cx50 gap junctions. However, due to instability of …

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A New Method Based On Pixel Density In Salt And Pepper Noise Removal, Uğur Erkan, Levent Gökrem Jan 2018

A New Method Based On Pixel Density In Salt And Pepper Noise Removal, Uğur Erkan, Levent Gökrem

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we deliver a new method to remove salt and pepper noise, which we refer to as based on pixel density filter (BPDF). The first step of the method is to determine whether or not a pixel is noisy, and then we decide on an adaptive window size that accepts the noisy pixel as the center. The most repetitive noiseless pixel value within the window is set as the new pixel value. By using 18 test images, we give the results of peak signal-to-noise ratio (PSNR), structural similarity (SSIM), image enhancement factor (IEF), standard median filter (SMF), adaptive …

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Transient- And Probabilistic Neural Network-Based Fault Classification In Ehv Three-Terminal Lines, Ravi Kumar Varma Bhupatiraju, Venkata Sesha Samba Siva Sarma Dhanikonda, Venkata Ramana Rao Pulipaka Jan 2018

Transient- And Probabilistic Neural Network-Based Fault Classification In Ehv Three-Terminal Lines, Ravi Kumar Varma Bhupatiraju, Venkata Sesha Samba Siva Sarma Dhanikonda, Venkata Ramana Rao Pulipaka

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a fast and accurate fault classifier for three-terminal transmission circuits. Traditional phasor-based methods fail to meet the high speed requirements of modern power grids and necessitate alternative solutions. The transient-based schemes use advanced signal processing techniques to achieve fast and accurate fault classification. As the three-terminal lines experience very pronounced transients during faults, the proposed method makes use of the fault-generated transients to quickly and correctly classify the fault. Many transient-based schemes fail to give the required accuracy since the transient patterns with relay-measured signals are highly influenced by fault conditions. Therefore, a thorough analysis of transient …

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Bagged Tree Classification Of Arrhythmia Using Wavelets For Denoising, Compression, And Feature Extraction, Özgür Tomak, Temel Kayikçioğlu Jan 2018

Bagged Tree Classification Of Arrhythmia Using Wavelets For Denoising, Compression, And Feature Extraction, Özgür Tomak, Temel Kayikçioğlu

Turkish Journal of Electrical Engineering and Computer Sciences

Arrhythmia, also known as dysrhythmia, is a condition involving an irregular heartbeat. A problem in the heart may cause problems in other organs, and as time passes, this will lead to more severe problems. Arrhythmia must be detected at an early stage to prevent such a problem occurring in the heart. Detection of arrhythmia from an electrocardiogram is an easy method that does not need much equipment and does not harm the patient. The purpose of this research is to find a faster and more accurate system to classify nine classes of arrhythmia. The St. Petersburg Institute of Cardiological Technics …

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Multilabel Learning For The Online Transient Stability Assessment Of Electric Power Systems, Peyman Beyranvand, Veysel Murat İstemi̇han Genç, Zehra Çataltepe Jan 2018

Multilabel Learning For The Online Transient Stability Assessment Of Electric Power Systems, Peyman Beyranvand, Veysel Murat İstemi̇han Genç, Zehra Çataltepe

Turkish Journal of Electrical Engineering and Computer Sciences

Dynamic security assessment of a large power system operating over a wide range of conditions requires an intensive computation for evaluating the system's transient stability against a large number of contingencies. In this study, we investigate the application of multilabel learning for improving training and prediction time, along with the prediction accuracy, of neural networks for online transient stability assessment of power systems. We introduce a new multilabel learning method, which uses a contingency clustering step to learn similar contingencies together in the same multilabel multilayer perceptron. Experimental results on two different power systems demonstrate improved accuracy, as well as …

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Novel Modified Impedance-Based Methods For Fault Location In The Presence Of A Fault Current Limiter, Javad Barati, Aref Doroudi Jan 2018

Novel Modified Impedance-Based Methods For Fault Location In The Presence Of A Fault Current Limiter, Javad Barati, Aref Doroudi

Turkish Journal of Electrical Engineering and Computer Sciences

A fault current limiter (FCL) is promising novel electric equipment to effectively reduce excessive short circuit current in power networks. The presence of a FCL at the time of a fault occurrence makes it necessary to consider new settings for protective relays and fault locators. This paper examines the presence of a FCL in power networks and its effects on single-ended impedance-based fault location methods. It will be shown that FCL deployment in a transmission line makes the traditional fault location method inefficient. Two modified methods are presented to solve the problem. The modified methods locate the fault point using …

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Performance Evaluation Of Alumina Trihydrate And Silica-Filled Silicone Rubber Composites For Outdoor High-Voltage Insulations, Hidayatullah Khan, Muhammad Amin, Ayaz Ahmad Jan 2018

Performance Evaluation Of Alumina Trihydrate And Silica-Filled Silicone Rubber Composites For Outdoor High-Voltage Insulations, Hidayatullah Khan, Muhammad Amin, Ayaz Ahmad

Turkish Journal of Electrical Engineering and Computer Sciences

In recent years, silicone rubber-based composites have been widely investigated for outdoor applications due to their promising insulating properties. However, mechanical, thermal, and tracking properties of pure silicone rubber are very poor, which restrains its application for long-term performance. In this research work, the influence of microsized alumina trihydrate (ATH) and micro/nanosized silica (SiO$_{2})$ fillers on mechanical, thermal, and electrical properties of room temperature vulcanized silicone rubber (RTV-SiR) has been studied. SiR-blends with varying amounts of ATH and SiO$_{2}$ particles were prepared by blending in a two-roll mixing mill, compression molding, and postcuring processes in sequence. In order to evaluate …

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A Selective Frequency Reconfigurable Bandstop Metamaterial Filter For Wlan Applications, Bachir Belkadi, Zoubir Mahdjoub, Mohammed Lamine Seddiki, Mourad Nedil Jan 2018

A Selective Frequency Reconfigurable Bandstop Metamaterial Filter For Wlan Applications, Bachir Belkadi, Zoubir Mahdjoub, Mohammed Lamine Seddiki, Mourad Nedil

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, two designs of bandstop filters are presented and implemented, each one composed of a coplanar waveguide loaded with a resonator. The first design has a structure with circular resonators, and the second design is a frequency reconfigurable filter with a rectangular spiral resonator and PIN diodes. The designs are based on the use of metamaterial to create notch filters for microwave applications. The Nicolson--Ross--Weir method, used to extract the refractive index, is also described to highlight the supernatural electromagnetic characteristic of metamaterials. From the simulation results, the filters exhibit high frequency selectivity via the presence of reflection …

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Design Of Fusion-Based Underwater Image Enhancement Method In Video Stream, Pann Mya Hmue Jan 2018

Design Of Fusion-Based Underwater Image Enhancement Method In Video Stream, Pann Mya Hmue

Chulalongkorn University Theses and Dissertations (Chula ETD)

This thesis has designed a fusion-based enhancement method for underwater images and video streams which are mainly distorted by color changes, poor illumination, and water particles. The main objective of image fusion is to achieve a comprehensive result which is appropriate for the human visual system. In this thesis, our goal is to use a straight forward and not computationally intensive reconstruction. As a result, the underwater images or video streams are partially restored from the original ones. Firstly, the 5.8 GHz transmitter and receiver set are used to carry the input data from the camera which is placed inside …

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Development Of Texture Weighted Fuzzy C-Means Algorithm For 3d Brain Mri Segmentation, Ji Young Lee Jan 2018

Development Of Texture Weighted Fuzzy C-Means Algorithm For 3d Brain Mri Segmentation, Ji Young Lee

Electronic Theses and Dissertations

The segmentation of human brain Magnetic Resonance Image is an essential component in the computer-aided medical image processing research. Brain is one of the fields that are attracted to Magnetic Resonance Image segmentation because of its importance to human. Many algorithms have been developed over decades for brain Magnetic Resonance Image segmentation for diagnosing diseases, such as tumors, Alzheimer, and Schizophrenia. Fuzzy C-Means algorithm is one of the practical algorithms for brain Magnetic Resonance Image segmentation. However, Intensity Non- Uniformity problem in brain Magnetic Resonance Image is still challenging to existing Fuzzy C-Means algorithm. In this paper, we propose the …

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Urea And Rgo Additives To Iodine/Triiodide Electrolyte For Higher Efficiency Dye-Sensitized Solar Cells, Salem Abdulkarim Jan 2018

Urea And Rgo Additives To Iodine/Triiodide Electrolyte For Higher Efficiency Dye-Sensitized Solar Cells, Salem Abdulkarim

Electronic Theses and Dissertations

This research investigated urea and reduced graphene oxide (rGO) as potential additives to a dye-sensitized solar cell (DSSC) iodide/triode electrolyte, in order to enhance overall electrical performance. Additive concentrations of 0, 2, 5, 10, and 15 wt% were investigated. In general, both additives were found to enhance DSSC electrical performance with respect to open circuit voltage Voc and DSSC fill factor FF. The greatest enhancement in these parameters occurred at an additive concentration of 10 wt%. Urea produced a greater degree of enhancement than rGO; the overall efficiency was increased by 10.17±0.01% for urea vs 9.57±0.01% for rGO. The specific …

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Development Of Vegetation Mapping With Deep Convolutional Neural Network, Sae-Han Suh Jan 2018

Development Of Vegetation Mapping With Deep Convolutional Neural Network, Sae-Han Suh

Electronic Theses and Dissertations

The Precision Agriculture plays a crucial part in the agricultural industry about improving the decision-making process. It aims to optimally allocate the resources to maintain the sustainable productivity of farmland and reduce the use of chemical compounds. [17] However, the on-site inspection of vegetations often falls to researchers’ trained eye and experience, when it deals with the identification of the non-crop vegetations. Deep Convolution Neural Network (CNN) can be deployed to mitigate the cost of manual classification. Although CNN outperforms the other traditional classifiers, such as Support Vector Machine, it is still in question whether CNN can be deployable in …

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Localization Of Microcalcification On The Mammogram Using Deep Convolutional Neural Network, Jieun Jhang Jan 2018

Localization Of Microcalcification On The Mammogram Using Deep Convolutional Neural Network, Jieun Jhang

Electronic Theses and Dissertations

Breast cancer is the most common cancer in women worldwide, and the mammogram is the most widely used screening technique for breast cancer. To make a diagnosis in the early stage of breast cancer, the appearance of masses and microcalcifications on the mammogram are two crucial indicators. Notably, the early detection of malignant microcalcifications can facilitate the diagnosis and the treatment of breast cancer at the appropriate time. Making an accurate evaluation on microcalcifications is a timeconsuming and challenging task for the radiologists due to the small size and the low contrast of microcalcification. Compared to the background and mammogram …

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An Approach To Finding Parking Space Using The Csi-Based Wifi Technology, Yunfan Zhang Jan 2018

An Approach To Finding Parking Space Using The Csi-Based Wifi Technology, Yunfan Zhang

Electronic Theses and Dissertations

With ever-increasing number of vehicles and shortages of parking spaces, parking has always been a very important issue in transportation. It is necessary to use advanced intelligent technologies to help drivers find parking spaces, quickly. In this thesis, an approach to finding empty spaces in parking lots using the CSI-based WiFi technology is presented. First, the channel state information (CSI) of received WiFi signals is analyzed. The features of CSI data that are strongly correlated with the number of empty slots in parking lots are identified and extracted. A machine learning technique to perform multi-class classification that categorizes the input …

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Wi-Fi Finger-Printing Based Indoor Localization Using Nano-Scale Unmanned Aerial Vehicles, Appala Narasimha Raju Chekuri Jan 2018

Wi-Fi Finger-Printing Based Indoor Localization Using Nano-Scale Unmanned Aerial Vehicles, Appala Narasimha Raju Chekuri

Electronic Theses and Dissertations

Explosive growth in the number of mobile devices like smartphones, tablets, and smartwatches has escalated the demand for localization-based services, spurring development of numerous indoor localization techniques. Especially, widespread deployment of wireless LANs prompted ever increasing interests in WiFi-based indoor localization mechanisms. However, a critical shortcoming of such localization schemes is the intensive time and labor requirements for collecting and building the WiFi fingerprinting database, especially when the system needs to cover a large space. In this thesis, we propose to automate the WiFi fingerprint survey process using a group of nano-scale unmanned aerial vehicles (NAVs). The proposed system significantly …

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Engineering Of Hole Transport And Perovskite Absorber Layers To Achieve High Efficiency And Stable Perovskite Solar Cells, Sally Mabrouk Jan 2018

Engineering Of Hole Transport And Perovskite Absorber Layers To Achieve High Efficiency And Stable Perovskite Solar Cells, Sally Mabrouk

Electronic Theses and Dissertations

Perovskite solar cells (PSCs) offer tremendous potential for simple and low-cost solution-based fabrication with high power conversion efficiency, making it a promising renewable energy source alternative to the most common non-renewable energy sources as fossil fuels. The most widely used perovskite for solar cell applications is methylammonium lead triiodide (CH3NH3PbI3). The two structures for PSC are the regular nip device typically fabricated using Spiro- OMeTAD as a hole transport material (HTM), and the inverted pin device fabricated using PEDOT:PSS as a HTM. They have achieved over 20% power conversion efficiency. However, devices are not reproducible or stable and HTMs are …

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Review Of The Effectiveness Of Impulse Testing For The Evaluation Of Cable Insulation Quality And Recommendations For Quality Testing, Adrian Coughlan, Joseph Kearney, Tom Looby Jan 2018

Review Of The Effectiveness Of Impulse Testing For The Evaluation Of Cable Insulation Quality And Recommendations For Quality Testing, Adrian Coughlan, Joseph Kearney, Tom Looby

Conference papers

Abstract— This project investigates impulse breakdown testing as a means of determining the as constructed standard of MV power cable. A literature survey is undertaken to elucidate the place of this test in an overall cable test regime and to determine the factors that impact on the performance of the test method. Testing was undertaken on ESB Networks cables to establish if a merit order ranking was feasible based on this test and to determine if the test could detect defects in the inner semiconducting layer. Based on this, conclusions and recommendations are made regarding the overall applicability and usefulness …

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Data Driven Prediction Model (Ddpm) For Server Inlet Temperature Prediction In Raised-Floor Data Centers, Raymond Lloyd, Marek Rebow Jan 2018

Data Driven Prediction Model (Ddpm) For Server Inlet Temperature Prediction In Raised-Floor Data Centers, Raymond Lloyd, Marek Rebow

Conference papers

Data centers account for approx. 1.4% of the world’s electricity consumption, of which up to 50% of that power is dedicated to keeping the actual equipment cool. This represents a huge opportunity to reduce data center energy consumption by tackling the cooling system operations with focus on thermal management. This work presents a novel Data Driven Predictive Model (DDPM) for temperature prediction of server inlet temperatures that utilises high resolution empirical temperature measurements from 52 real-life data centers. A knowledge-base of temperature data and related physical features, created via clustering techniques was used to train a series of artificial neural …

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Proportional-Integral And Proportional-Resonant Based Control Strategy For Puc Inverters, Samet Biricik, Hasan Komurcugil Jan 2018

Proportional-Integral And Proportional-Resonant Based Control Strategy For Puc Inverters, Samet Biricik, Hasan Komurcugil

Conference papers

In this paper, a proportional-integral (PI) and proportional-resonant (PR) based control strategy is proposed for packed-U-cell (PUC) inverters. In the conventional PI-PI based control strategy, while the first PI regulates the DC capacitor voltage, the second PI regulates the AC load current. However, it is shown that the second PI cannot guarantee zero tracking error in the load current. The main reason of this comes from the fact that PI controllers are not able to achieve zero tracking error for the AC signals. Also, in an attempt to reduce the tracking error by tuning PI gains distorts the load current. …

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A Machine Learning Management Model For Qoe Enhancement In Next-Generation Wireless Ecosystems, Eva Ibarrola, Mark Davis, Camille Voisin, Ciara Close, Leire Cristobo Jan 2018

A Machine Learning Management Model For Qoe Enhancement In Next-Generation Wireless Ecosystems, Eva Ibarrola, Mark Davis, Camille Voisin, Ciara Close, Leire Cristobo

Conference papers

Next-generation wireless ecosystems are expected to comprise heterogeneous technologies and diverse deployment scenarios. Ensuring a good quality of service (QoS) will be one of the major challenges of next-generation wireless systems on account of a variety of factors that are beyond the control of network and service providers. In this context, ITU-T is working on updating the various Recommendations related to QoS and users' quality of experience (QoE). Considering the ITU-T QoS framework, we propose a methodology to develop a global QoS management model for next-generation wireless ecosystems taking advantage of big data and machine learning. The results from a …

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On Fixed Beamforming In Sectored Mmwave Ultra Dense Networks At 73ghz, Jasmina Mcmenamy, Haris Kremo, George A. Ropokis, Adam Narbudowicz Jan 2018

On Fixed Beamforming In Sectored Mmwave Ultra Dense Networks At 73ghz, Jasmina Mcmenamy, Haris Kremo, George A. Ropokis, Adam Narbudowicz

Conference papers

We investigate the use of fixed analogue transmit beamforming for downlink communication in millimetre-wave (mmWave) band ultra-dense networks (UDNs) at 73GHz. Our simulation study is based on 3D radiation patterns using a real design of large planar antenna arrays with different horizontal beamwidths and full characterisation of interference. The effects of network densification are captured through different ratios of the number of access points (APs) to the number of users. We quantify the system's performance by evaluating outage and achievable rate. The results show that users with rates around the mean benefit more from the densification than from narrowing the …

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Design And Development Of An Emergency System For Children In A Hot Car At Risk Of Heatstroke, Nathan Kisha Jan 2018

Design And Development Of An Emergency System For Children In A Hot Car At Risk Of Heatstroke, Nathan Kisha

Research Opportunities for Engineering Undergraduates (ROEU) Program 2017-18

Since 1998, an average of 37 children have died every year due to heat-related deaths after being stuck in a vehicle, making it the leading cause of non-crash-related fatalities among children. This creates an opportunity to create a system which will be able to detect this danger and do something in order to prevent it. There are 4 main objectives for the system to be able to accomplish: 1) determine if the temperature in the car poses a risk, 2) use an alarm to provide a warning and wake up a sleeping child, 3) determine if someone is in the …

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Eeg And Emg Sensorimotor Measurements To Assess Proprioception Following Acl Reconstruction, Teagan Frances Northrup Jan 2018

Eeg And Emg Sensorimotor Measurements To Assess Proprioception Following Acl Reconstruction, Teagan Frances Northrup

Honors Theses and Capstones

The Anterior Cruciate Ligament (ACL) is the primary source of rotational stability in the knee by preventing the tibia from sliding in front of the femur. When the ACL is torn, it typically must be repaired through reconstructive surgery which results in proprioceptive deficiencies in the knee. Proprioception plays an important role in understanding where one’s knee is in space, sensing movement and reacting accordingly. This study examines an alternative method of measuring proprioceptive responses to a stimulus (motion) by using electromyogram (EMG) and electroencephalogram (EEG) signals to observe muscle and brain activity. Two participants (one with an ACL reconstruction …

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Parallelization And Scalability Analysis Of The \\[1pc] 3d Spatially Variant Lattice Algorithm, Henry Roger Moncada Lopez Jan 2018

Parallelization And Scalability Analysis Of The \\[1pc] 3d Spatially Variant Lattice Algorithm, Henry Roger Moncada Lopez

Open Access Theses & Dissertations

The purpose of this research is to design a faster implementation of an algorithm to generate 3D spatially variant lattices (SVL) and improve its performance when it is running on a parallel computer system. The algorithm is used to synthesize a SVL for a periodic structure. The algorithm has the ability to spatially vary the unit cell, the orientation of the unit cells, lattice spacing, fill fraction, material composition, and lattice symmetry. The algorithm produces a lattice that is smooth, continuous and free of defects. The lattice spacing remains strikingly uniform even when the lattice is spatially varied. This is …

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Investigation Of Temperature Dependence Of Microfibre Coil Resonators, Yu Yin, Jibo Yu, Yuxuan Jiang, Shi Li, Jing Ren, Gerald Farrell, Elfed Lewis, Pengfei Wang Jan 2018

Investigation Of Temperature Dependence Of Microfibre Coil Resonators, Yu Yin, Jibo Yu, Yuxuan Jiang, Shi Li, Jing Ren, Gerald Farrell, Elfed Lewis, Pengfei Wang

Articles

The temperature-sensitive performance of a microfiber coil resonator (MCR) is thoroughly investigated. The MCR is fabricated by wrapping a microfiber on a PMMA rod coated with a UV-curable low refractive index epoxy. The temperature sensitivity is measured by investigating the correlation between the shift of the resonant wavelength and the surrounding temperature. It is determined that a range of parameters of the MCRs, including the gap between two adjacent rings, the diameter of the supporting rod, the number of rings, and the diameter of the microfiber, have a great influence on the temperature sensitivity of the MCRs. By optimizing the …

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Investigation Of A Novel Sms Fiber Based Planar Multimode Waveguide And Its Sensing Performance, Xianfan Wang, Jiquan Zhang, Ke Tian, Shunbin Wang, Libo Yuan, Elfed Lewis, Gerald Farrell, Pengfei Wang Jan 2018

Investigation Of A Novel Sms Fiber Based Planar Multimode Waveguide And Its Sensing Performance, Xianfan Wang, Jiquan Zhang, Ke Tian, Shunbin Wang, Libo Yuan, Elfed Lewis, Gerald Farrell, Pengfei Wang

Articles

A novel, MMI-based all-fiber structure, which consists of two single-mode fibers and a multimode fiber polished on both sides, is described. The light propagation characteristics of this fiber structure, as well as its superior sensing performance, are analyzed theoretically by using the beam propagation method (BPM). This fiber structure demonstrates a significant spectral response to changes of the surrounding refractive index (RI), and the measured results exhibit good agreement with the predicted data. The measured average RI sensitivity is as high as 151.29 nm/RIU over an RI range from 1.3450 to 1.4050, when the polished depth is 30 µm on …

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A Simple All-Fiber Comb Filter Based On The Combined Effect Of Multimode Interference And Mach- Zehnder Interferometer, Guorui Zhou, Rahul Kumar, Qiang Wu, W. P. Ng, Richard Binns, Lalam Nageswara, Xinxiang Miao, Longfei Niu, Xiaodong Yuan, Yuliya Semenova, Gerald Farrell, Jinhui Yuan, Chongxiu Yu, Xinzhu Sang, Xiangjun Xin, Bo Liu, Haibing Lv, Yong Qing Fu Jan 2018

A Simple All-Fiber Comb Filter Based On The Combined Effect Of Multimode Interference And Mach- Zehnder Interferometer, Guorui Zhou, Rahul Kumar, Qiang Wu, W. P. Ng, Richard Binns, Lalam Nageswara, Xinxiang Miao, Longfei Niu, Xiaodong Yuan, Yuliya Semenova, Gerald Farrell, Jinhui Yuan, Chongxiu Yu, Xinzhu Sang, Xiangjun Xin, Bo Liu, Haibing Lv, Yong Qing Fu

Articles

A polarization-dependent all-fiber comb filter based on a combination effect of multimode interference and Mach-Zehnder interferometer was proposed and demonstrated. The comb filter was composed with a short section of multimode fiber (MMF) fusion spliced with a conventional single mode fiber on the one side and a short section of a different type of optical fiber on the other side. The second type of optical fiber is spliced to the MMF with a properly designed misalignment. Different types and lengths of fibers were used to investigate the influence of fiber types and lengths on the performance of the comb filter. …

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High-Sensitivity Salinity Sensor Based On Optical Microfiber Coil Resonator, Y. Yin, S. Li, J. Ren, Gerald Farrell, E. Lewis, Pengfei Wang Jan 2018

High-Sensitivity Salinity Sensor Based On Optical Microfiber Coil Resonator, Y. Yin, S. Li, J. Ren, Gerald Farrell, E. Lewis, Pengfei Wang

Articles

In recent years, salinity sensing has attracted much attention in potential areas ranging from marine monitoring, marine circulation, marine climate and environment protection in oceanography [1–4]. Generally, traditional methods of salinity measurement have been based on electronic methods (electrochemical) to detect the existence of chlorine ions of the seawater [5,6]. However, this method is affected greatly from the harsh environment, such as high corrosivity, extreme temperature and strong electromagnetic interference and is not used widely in micro scale due to its large size and complex structure. Electrochemical sensors are also prone to cross-sensitivity from and can even be damaged by …

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Silica Gel Coated Spherical Micro Resonator For Ultra-High Sensitivity Detection Of Ammonia Gas Concentration In Air, Arun Mallik, Gerald Farrell, Dejun Liu, Vishnu Kavungal, Qiang Wu, Yuliya Semenova Jan 2018

Silica Gel Coated Spherical Micro Resonator For Ultra-High Sensitivity Detection Of Ammonia Gas Concentration In Air, Arun Mallik, Gerald Farrell, Dejun Liu, Vishnu Kavungal, Qiang Wu, Yuliya Semenova

Articles

A silica gel coated microsphere resonator is proposed and experimentally demonstrated for measurements of ammonia (NH3) concentration in air with ultra-high sensitivity. The optical properties of the porous silica gel layer change when it is exposed to low (parts per million (ppm)) and even ultra-low (parts per billion (ppb)) concentrations of ammonia vapor, leading to a spectral shift of the WGM resonances in the transmission spectrum of the fiber taper. The experimentally demonstrated sensitivity of the proposed sensor to ammonia is estimated as 34.46 pm/ppm in the low ammonia concentrations range from 4 ppm to 30 ppm using an optical …

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