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Fan X, Amiri AJ, Fidan B, Jeon S. Unsupervised Stereo Matching with Surface Normal Assistance for Indoor Depth Estimation. Sensors (Basel) 2023; 23:9850. [PMID: 38139695 PMCID: PMC10747815 DOI: 10.3390/s23249850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 12/04/2023] [Accepted: 12/13/2023] [Indexed: 12/24/2023]
Abstract
To obtain more accurate depth information with stereo cameras, various learning-based stereo-matching algorithms have been developed recently. These algorithms, however, are significantly affected by textureless regions in indoor applications. To address this problem, we propose a new deep-neural-network-based data-driven stereo-matching scheme that utilizes the surface normal. The proposed scheme includes a neural network and a two-stage training strategy. The neural network involves a feature-extraction module, a normal-estimation branch, and a disparity-estimation branch. The training processes of the feature-extraction module and the normal-estimation branch are supervised while the training of the disparity-estimation branch is performed unsupervised. Experimental results indicate that the proposed scheme is capable of estimating the surface normal accurately in textureless regions, leading to improvement in the disparity-estimation accuracy and stereo-matching quality in indoor applications involving such textureless regions.
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Affiliation(s)
- Xiule Fan
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave. W., Waterloo, ON N2L 3G1, Canada; (X.F.); (S.J.)
| | | | - Baris Fidan
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave. W., Waterloo, ON N2L 3G1, Canada; (X.F.); (S.J.)
| | - Soo Jeon
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave. W., Waterloo, ON N2L 3G1, Canada; (X.F.); (S.J.)
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Soares MD, Passos D, Castellanos PVG. Cognitive Radio with Machine Learning to Increase Spectral Efficiency in Indoor Applications on the 2.5 GHz Band. Sensors (Basel) 2023; 23:4914. [PMID: 37430827 DOI: 10.3390/s23104914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/01/2023] [Accepted: 05/05/2023] [Indexed: 07/12/2023]
Abstract
Due to the propagation characteristics in the 2.5 GHz band, the signal is significantly degraded by building entry loss (BEL), making coverage in indoor environments in some cases non-existent. Signal degradation inside buildings is a challenge for planning engineers, but it can be seen as a spectrum usage opportunity for a cognitive radio communication system. This work presents a methodology based on statistical modeling of data collected by a spectrum analyzer and the application of machine learning (ML) to leverage the use of those opportunities by autonomous and decentralized cognitive radios (CRs), independent of any mobile operator or external database. The proposed design targets using as few narrowband spectrum sensors as possible in order to reduce the cost of the CRs and sensing time, as well as improving energy efficiency. Those characteristics make our design especially interesting for internet of things (IoT) applications or low-cost sensor networks that may use idle mobile spectrum with high reliability and good recall.
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Affiliation(s)
| | - Diego Passos
- Instituto de Computação, Universidade Federal Fluminense, Niterói 24210-310, Brazil
- ISEL, Instituto Superior, de Engenharia de Lisboa, 1959-007 Lisboa, Portugal
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Kim JW, Chung SI, Kim PK, Ha TG, Yeop J, Lee W, Rasool S, Kim JY. Mechanically Stable Flexible Organic Photovoltaics with Silver Nanomesh for Indoor Applications. ACS Appl Mater Interfaces 2023; 15:5378-5386. [PMID: 36670528 DOI: 10.1021/acsami.2c22047] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Enhanced device performance of flexible organic solar cells (FOSCs) was achieved according to the development of organic solar cells (OSCs). OSCs are promising candidates as energy sources for low-power supply systems such as the Internet of Things (IoT) under indoor lighting environments. To apply FOSCs to flexible or wearable applications, they must be mechanically stable. In this study, we fabricated FOSCs with silver nanomesh (AgNM) as the bottom transparent conductive electrode (TCE). Instead of indium tin oxide (ITO), AgNMs were prepared using three pitches of 25, 50, and 100 μm with a square pattern, using a poly(ethylene terephthalate) (PET) substrate. Notably, the device using AgNMs with a pitch of 25 μm exhibited a power conversion efficiency (PCE) of 14.93% under 1 sun illumination and 17.91% under 1000 lux of light-emitting diode (LED) light conditions. Flexible devices using AgNMs maintained over 92% of their initial PCE under 1 sun illumination (PCE decreased to 12.98 from 14.04%) and over 92% when tested under 1000 lux of LED light illumination (PCE decreased to 16.57 from 17.91%) after 1000 instances of bending. These results demonstrate the advantages of using AgNMs as an alternative TCE under both 1 sun and indoor lightning environments and are promising candidates for flexible applications.
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Affiliation(s)
- Jae Won Kim
- Graduate School of Carbon Neutrality, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan44919, Republic of Korea
| | - Sung-Il Chung
- Nano Hybrid Technology Research Center, Korea Electrotechnology Research Institute, Miryang50463, Republic of Korea
| | - Pan Kyeom Kim
- Nano Hybrid Technology Research Center, Korea Electrotechnology Research Institute, Miryang50463, Republic of Korea
| | - Tae-Gyu Ha
- Nano Hybrid Technology Research Center, Korea Electrotechnology Research Institute, Miryang50463, Republic of Korea
| | - Jiwoo Yeop
- Graduate School of Carbon Neutrality, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan44919, Republic of Korea
| | - Woojin Lee
- Graduate School of Carbon Neutrality, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan44919, Republic of Korea
| | - Shafket Rasool
- Graduate School of Carbon Neutrality, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan44919, Republic of Korea
| | - Jin Young Kim
- Graduate School of Carbon Neutrality, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan44919, Republic of Korea
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Bi P, Ren J, Zhang S, Zhang T, Xu Y, Cui Y, Qin J, Hou J. Suppressing Energetic Disorder Enables Efficient Indoor Organic Photovoltaic Cells With a PTV Derivative. Front Chem 2021; 9:684241. [PMID: 34055749 PMCID: PMC8149913 DOI: 10.3389/fchem.2021.684241] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 04/12/2021] [Indexed: 11/13/2022] Open
Abstract
Indoor organic photovoltaics (IOPVs) cells have attracted considerable attention in the past few years. Herein, two PTV-derivatives, PTVT-V and PTVT-T, were used as donor materials to fabricate IOPV cells with ITCC as the acceptor. The preferred orientation of the crystals changed from edge-on to face-on after replacing the ethylene in the backbones of PTVT-V by the thiophene in that of PTVT-T. Besides, it was found that, the energetic disorder of the PTVT-T:ITCC based system is 58 meV, which is much lower than that of PTVT-V:ITCC-based system (70 meV). The lower energetic disorder in PTVT-T:ITCC leads to an efficient charge transfer, charge transport, and thus the weak charge recombination. As a result, a PCE of 9.60% under AM 1.5 G and a PCE of 24.27% under 1,000 lux (LED 2,700 K) with a low non-radiative energy loss of 0.210 eV were obtained based on PTVT-T:ITCC blend. The results indicate that to improve the PTV-derivatives photovoltaic properties by suppressing the energetic disorder is a promising way to realize low-cost IOPV cells.
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Affiliation(s)
- Pengqing Bi
- School of Chemistry and Biology Engineering, University of Science and Technology Beijing, Beijing, China
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular, Institute of Chemistry Chinese Academy of Sciences, Beijing, China
| | - Junzhen Ren
- School of Chemistry and Biology Engineering, University of Science and Technology Beijing, Beijing, China
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular, Institute of Chemistry Chinese Academy of Sciences, Beijing, China
| | - Shaoqing Zhang
- School of Chemistry and Biology Engineering, University of Science and Technology Beijing, Beijing, China
| | - Tao Zhang
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular, Institute of Chemistry Chinese Academy of Sciences, Beijing, China
| | - Ye Xu
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular, Institute of Chemistry Chinese Academy of Sciences, Beijing, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yong Cui
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular, Institute of Chemistry Chinese Academy of Sciences, Beijing, China
| | - Jinzhao Qin
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular, Institute of Chemistry Chinese Academy of Sciences, Beijing, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Jianhui Hou
- School of Chemistry and Biology Engineering, University of Science and Technology Beijing, Beijing, China
- State Key Laboratory of Polymer Physics and Chemistry, Beijing National Laboratory for Molecular, Institute of Chemistry Chinese Academy of Sciences, Beijing, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, China
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Park SY, Li Y, Kim J, Lee TH, Walker B, Woo HY, Kim JY. Alkoxybenzothiadiazole-Based Fullerene and Nonfullerene Polymer Solar Cells with High Shunt Resistance for Indoor Photovoltaic Applications. ACS Appl Mater Interfaces 2018; 10:3885-3894. [PMID: 29300449 DOI: 10.1021/acsami.7b18152] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We synthesized three semicrystalline polymers (PTTBTBO, PDTBTBO, and P2FDTBTBO) by modulating the intra- and intermolecular noncovalent Coulombic interactions and investigated their photovoltaic characteristics under various light intensities. Low series (Rs) and high shunt (Rsh) resistances are essential prerequisites for good device properties under standard illumination (100 mW cm-2). Considering these factors, among three polymers, PDTBTBO polymer solar cells (PSCs) exhibited the most desirable characteristics, with peak power conversion efficiencies (PCE) of 7.52 and 9.60% by being blended with PC71BM under standard and dim light (2.5 mW cm-2), respectively. P2FDTBTBO PSCs exhibited a low PCE of 3.69% under standard light due to significant charge recombination with high Rs (9.42 Ω cm2). However, the PCE was remarkably improved by 2.3 times (8.33% PCE) under dim light, showing negligible decrease in open-circuit voltage and remarkable increase in fill factor, which is due to an exceptionally high Rsh of over 1000 kΩ cm2. Rs is less significant under dim light because the generated current is too small to cause noticeable Rs-induced voltage losses. Instead, high Rsh becomes more important to avoid leakage currents. This work provides important tips to further optimize PSCs for indoor applications with low-power electronic devices such as Internet of things sensors.
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Affiliation(s)
- Song Yi Park
- Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 44919, Republic of Korea
| | - Yuxiang Li
- Department of Chemistry, Korea University , Seoul 136-713, Republic of Korea
- Department of Cogno-Mechatronics Engineering, Pusan National University , Miryang 627-706, Republic of Korea
| | - Jaewon Kim
- Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 44919, Republic of Korea
| | - Tack Ho Lee
- Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 44919, Republic of Korea
| | - Bright Walker
- Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 44919, Republic of Korea
| | - Han Young Woo
- Department of Chemistry, Korea University , Seoul 136-713, Republic of Korea
| | - Jin Young Kim
- Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 44919, Republic of Korea
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