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Chong Hyun Lee
Department of Ocean System Engineering, Jeju National University, PC 63243, Jeju, South Korea

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Journal article
Published: 27 May 2021 in IEEE Sensors Journal
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We propose a compact and configurable sensor system using the 4 GHz to 6 GHz frequency band. The proposed system can support three sensors and is designed to detect input samples by using intrinsic vector network analyzer (VNA) functions as well as a simple detection algorithm. The system is composed of three parts: a sensor interface, an RF resonance signal processing board and configurable graphical user interface (GUI) software for storing, processing and detecting the input signal. The resonant frequency and its root mean square (RMS) power are measured, and the margins of the frequency bandwidth and power are estimated by analyzing statistics of the measured bandwidth and power for sample detection. For evaluation of the proposed system, we used three rectangular cavity sensors for gasoline detection and obtained minimum margins of the resonant bandwidth and RMS power at 15.5 Mhz and 2.7837 dB, respectively. The subsequent experiments using the margins validated that the proposed system and algorithm flow show stable detection performance within two seconds for a maximum ten gasoline samples. Although this evaluation has been conducted for gasoline samples, it can be applied to other sensors for which resonance characteristics can be obtained within the proposed bandwidth.

ACS Style

Chong Hyun Lee; Yoon-Sang Jeong; Hina Ashraf. A Compact and Configurable Gasoline Detection System Using a Microwave Sensor. IEEE Sensors Journal 2021, 21, 18178 -18186.

AMA Style

Chong Hyun Lee, Yoon-Sang Jeong, Hina Ashraf. A Compact and Configurable Gasoline Detection System Using a Microwave Sensor. IEEE Sensors Journal. 2021; 21 (16):18178-18186.

Chicago/Turabian Style

Chong Hyun Lee; Yoon-Sang Jeong; Hina Ashraf. 2021. "A Compact and Configurable Gasoline Detection System Using a Microwave Sensor." IEEE Sensors Journal 21, no. 16: 18178-18186.

Journal article
Published: 01 October 2020 in IEEE Access
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The Drivability Index (DI) of gasoline is a measure of fuel performance of engine operations. Therefore, distinguishing a gasoline of specific DI in advance is useful for improving engine efficiency and maintenance. We consider the problem of distinguishing between normal gasoline and HiDI (High DI) gasolines and propose an electromagnetic wave-based rectangular cavity sensor. For commercialization, it is designed to have a simple structure and basic resonance mode TM110 in the common frequency range of 5 GHz to 6 GHz. The proposed sensor has a simple structure of monopole radiating electromagnetic waves and a metal rectangular cavity containing gasoline samples. By considering one commercial normal gasoline sample of permittivity 2.157 and five HiDI gasoline samples of permittivity in the range of 2.018 to 2.218, we obtain 11.5 MHz resonance separation at room temperature to the closest HiDI sample from the simulation and 8 MHz resonance separation from the fabricated sensor experiment. To verify the feasibility of the fabricated sensor under temperature variation from 0°C to 20°C, we derived a simple linear distinction function of resonance frequency and S11 parameter and obtained a minimum 4.4MHz resonance separation. These results showed that the distinction performance for normal gasoline is robust to temperature variations. Furthermore, we showed that the distinction property is robust to design parameter errors, installation position variations and sensing time variations. These results show that the proposed sensor can be utilized effectively for distinguishing normal gasoline.

ACS Style

Chong Hyun Lee; Yoon-Sang Jeong; Hina Ashraf. Rectangular Cavity Sensor for Distinguishing Between Normal and High-Drivability-Index Gasolines. IEEE Access 2020, 8, 182193 -182203.

AMA Style

Chong Hyun Lee, Yoon-Sang Jeong, Hina Ashraf. Rectangular Cavity Sensor for Distinguishing Between Normal and High-Drivability-Index Gasolines. IEEE Access. 2020; 8 (99):182193-182203.

Chicago/Turabian Style

Chong Hyun Lee; Yoon-Sang Jeong; Hina Ashraf. 2020. "Rectangular Cavity Sensor for Distinguishing Between Normal and High-Drivability-Index Gasolines." IEEE Access 8, no. 99: 182193-182203.

Journal article
Published: 24 October 2019 in Sensors
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In this paper, a cylindrical cavity sensor based on microwave resonant theory is proposed to distinguish between various driveability index gasolines under temperature variations. The working principle of the proposed sensor is based on the fact that the change in permittivity of gasoline samples inside cavity sensor will also cause a change in resonant frequency. The proposed sensor has good sensitivity in terms of resonant frequency separation, which enables it to capture the minute permittivity changes and distinguish different gasolines. By using a normal gasoline permittivity of 2.15 and changing sensor dimension parameters, the sensor was designed by high-frequency structure simulator (HFSS). The designed sensor has a resonant frequency of 7.119 GHz for the TM012 mode with a 19.2 mm radius, a 35 mm height, and one-port coupling probe of 8 mm height. The proposed cylindrical cavity sensor shows advantages of excellent resonant characteristics of small cavity size and small sample amount. To optimize and verify the parameters of the sensor, many experiments have been carried out using HFSS and a vector network analyzer (VNA). Consequently, the proposed sensor is proven to be robust to temperature changes in terms of resonant frequency separation. The minimum frequency separation to distinguish gasoline samples is found to be larger than 29 MHz with reflection coefficients under −11 dB for temperature changes from −35 °C to 0 °C. The consistency of experimental and theoretical results also are presented, which guarantees accuracy of the sensor for the distinction of gasoline.

ACS Style

Chong Hyun Lee; Yoon-Sang Jeong; Hina Ashraf. Cylindrical Cavity Sensor for Distinction of Various Driveability Index Gasoline with Temperature Robustness. Sensors 2019, 19, 4626 .

AMA Style

Chong Hyun Lee, Yoon-Sang Jeong, Hina Ashraf. Cylindrical Cavity Sensor for Distinction of Various Driveability Index Gasoline with Temperature Robustness. Sensors. 2019; 19 (21):4626.

Chicago/Turabian Style

Chong Hyun Lee; Yoon-Sang Jeong; Hina Ashraf. 2019. "Cylindrical Cavity Sensor for Distinction of Various Driveability Index Gasoline with Temperature Robustness." Sensors 19, no. 21: 4626.

Journal article
Published: 14 October 2019 in Sensors
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A parametric array (PA) loudspeaker is a highly directional audio source that might grant one's convenience if it is used with mobile devices. However, conventional PA loudspeakers is almost impossible to apply in mobile devices using a battery because of the large power consumption and large device size. In this study, a PA loudspeaker system (PALS) was fabricated and evaluated to show that those difficulties could be overcome to apply it to mobile devices. In order to construct a PALS for demonstration, a power amplifier and signal-processing unit should also be properly designed and built. The PA source transducer should also be designed and built for a mobile device application. These components were integrated into a single PALS. The PALS generated a 125-dB primary wave and 62 dB of a different frequency wave (DFW) through the PA at 0.45 m in a 3 m × 3 m × 2 m semi-anechoic chamber. We confirmed that the half-power bandwidth (HPBW) formed a 6° beam at 83 kHz of DFW and 90 kHz of the primary wave (PW), and the HPBW formed a 7.3° beam at 5 kHz of DFW and a 7.1° beam at 10 kHz of DFW, respectively. Lastly, the power required was 6.65 W without a matching circuit, and 3.25 W with such a circuit.

ACS Style

Hongmin Ahn; Kyounghun Been; In-Dong Kim; Chong Hyun Lee; Wonkyu Moon. A Critical Step to Using a Parametric Array Loudspeaker in Mobile Devices. Sensors 2019, 19, 4449 .

AMA Style

Hongmin Ahn, Kyounghun Been, In-Dong Kim, Chong Hyun Lee, Wonkyu Moon. A Critical Step to Using a Parametric Array Loudspeaker in Mobile Devices. Sensors. 2019; 19 (20):4449.

Chicago/Turabian Style

Hongmin Ahn; Kyounghun Been; In-Dong Kim; Chong Hyun Lee; Wonkyu Moon. 2019. "A Critical Step to Using a Parametric Array Loudspeaker in Mobile Devices." Sensors 19, no. 20: 4449.

Journal article
Published: 12 September 2018 in Nanotechnology
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With the view towards future non-volatile random access memories that can be integrated at a large scale, extensive study on resistive switching (RS) devices arranged in a crossbar array is currently underway. Although the crossbar array architecture offers relatively simple and acceptable scalability, the presence of sneak current is recognized as a critical issue that needs to be resolved at the device level. In addressing this issue, we demonstrate a new type of RS device fabricated by combining graphene oxide (G-O) and zinc oxide (ZnO) with current-voltage (I-V) characteristics highly-asymmetric depending on the polarity of bias voltage. The distincitve highly-asymmetric I-V characteristics result from the presence of a hetero-junction interface formed beween the G-O and ZnO layers. This hetero-junction manifests resistnace in the range of GΩ under both forward and reverse bias voltage when the device is in the OFF state, in contrast, when the device is in the ON state, it exhibits resitance in the range of MΩ or kΩ under forward bias and GΩ under reverse bias, respectively. We propose to employ demonstrated RS devices with highly-asymmetric I-V characteristics to mitigate adverse effects of the sneak current.

ACS Style

Shawkat Ali; Jinho Bae; Chong Hyun Lee; Nobuhiko Kobayashi; Sangho Shin; Adnan Ali. Resistive switching device with highly asymmetric current–voltage characteristics: a solution to backward sneak current in passive crossbar arrays. Nanotechnology 2018, 29, 455201 .

AMA Style

Shawkat Ali, Jinho Bae, Chong Hyun Lee, Nobuhiko Kobayashi, Sangho Shin, Adnan Ali. Resistive switching device with highly asymmetric current–voltage characteristics: a solution to backward sneak current in passive crossbar arrays. Nanotechnology. 2018; 29 (45):455201.

Chicago/Turabian Style

Shawkat Ali; Jinho Bae; Chong Hyun Lee; Nobuhiko Kobayashi; Sangho Shin; Adnan Ali. 2018. "Resistive switching device with highly asymmetric current–voltage characteristics: a solution to backward sneak current in passive crossbar arrays." Nanotechnology 29, no. 45: 455201.

Journal article
Published: 31 July 2018 in Journal of the Institute of Electronics and Information Engineers
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본 논문에서는 경유 내 불순물 함유량 측정을 위한 전자파 기반의 마이크로스트립 패치 센서를 제안한다. 경유는 고유 유전율을 가지고 있으며, 이는 경유 내 불순 성분의 함유량에 따른 변화를 가진다. 제안하는 마이크로스트립 패치 센서는 경유를 포함하는 담는 용기(Enclosure)와 경유와 접촉하는 방사 패치로 구성되며, 경유의 유전율의 변화에 따른 공진주파수의 변화를 가짐으로써 경유 내 불순물 함유량의 측정을 가능하게 한다. 설계된 센서에 대한 전체파(Full wave analysis) 분석 결과, 유전율 0.05변화에 대해 약 24MHz의 공진주파수 변화를 가지는 것을 확인하였다. 또한 실측 실험 결과, 6.3ppm의 불순물 함유량 변화에 따라 300kHz에서 800kHz의 공진주파수 변화 폭을 가지며, 엔진세척제 첨가율 5% 미만에 대해 2153.4MHz 이상의 공진주파수와 10% 첨가율에 대해 2152.6MHz를 공진주파수를 가지는 것을 확인하였다. 끝으로, 타 경유사 경유에 대한 실험을 통해 경유의 품질 관리를 위한 실용화 가능성을 확인하였다.

ACS Style

Yoonsang Jeong; Kibae Lee; Chong Hyun Lee. Microstrip Patch Sensor for Determination of Impurity Content in Diesel. Journal of the Institute of Electronics and Information Engineers 2018, 55, 95 -101.

AMA Style

Yoonsang Jeong, Kibae Lee, Chong Hyun Lee. Microstrip Patch Sensor for Determination of Impurity Content in Diesel. Journal of the Institute of Electronics and Information Engineers. 2018; 55 (7):95-101.

Chicago/Turabian Style

Yoonsang Jeong; Kibae Lee; Chong Hyun Lee. 2018. "Microstrip Patch Sensor for Determination of Impurity Content in Diesel." Journal of the Institute of Electronics and Information Engineers 55, no. 7: 95-101.

Journal article
Published: 01 April 2018 in Composites Part A: Applied Science and Manufacturing
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ACS Style

Gul Hassan; Jinho Bae; Arshad Hassan; Shawkat Ali; Chong Hyun Lee; Yohan Choi. Ink-jet printed stretchable strain sensor based on graphene/ZnO composite on micro-random ridged PDMS substrate. Composites Part A: Applied Science and Manufacturing 2018, 107, 519 -528.

AMA Style

Gul Hassan, Jinho Bae, Arshad Hassan, Shawkat Ali, Chong Hyun Lee, Yohan Choi. Ink-jet printed stretchable strain sensor based on graphene/ZnO composite on micro-random ridged PDMS substrate. Composites Part A: Applied Science and Manufacturing. 2018; 107 ():519-528.

Chicago/Turabian Style

Gul Hassan; Jinho Bae; Arshad Hassan; Shawkat Ali; Chong Hyun Lee; Yohan Choi. 2018. "Ink-jet printed stretchable strain sensor based on graphene/ZnO composite on micro-random ridged PDMS substrate." Composites Part A: Applied Science and Manufacturing 107, no. : 519-528.

Journal article
Published: 31 March 2018 in Journal of the Institute of Electronics and Information Engineers
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ACS Style

Kibae Lee; Juho Kim; Myoung Jun Cheong; Young Woo Ryu; Jinho Bae; Chong Hyun Lee. Separation and Denoising Algorithm of Passive Sonar Target Signals in Frequency Domain. Journal of the Institute of Electronics and Information Engineers 2018, 55, 88 -96.

AMA Style

Kibae Lee, Juho Kim, Myoung Jun Cheong, Young Woo Ryu, Jinho Bae, Chong Hyun Lee. Separation and Denoising Algorithm of Passive Sonar Target Signals in Frequency Domain. Journal of the Institute of Electronics and Information Engineers. 2018; 55 (3):88-96.

Chicago/Turabian Style

Kibae Lee; Juho Kim; Myoung Jun Cheong; Young Woo Ryu; Jinho Bae; Chong Hyun Lee. 2018. "Separation and Denoising Algorithm of Passive Sonar Target Signals in Frequency Domain." Journal of the Institute of Electronics and Information Engineers 55, no. 3: 88-96.

Article
Published: 15 January 2018 in Journal of Materials Science: Materials in Electronics
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Nanocomposite materials are being used for different applications due to their hybrid and unique properties. In this paper, we propose a humidity sensor based on Graphene and zinc oxide nanocomposite thin film. The composite combines the advantages of both the individual materials and improves sensor performance. Addition of conductive graphene to the insulator ZnO results in fall of intrinsic impedance and also in improvement of sensitivity at low relative humidity levels. The sensor consists of silver inter-digital electrodes (IDEs) that are printed on a low cost transparent polyethyleneterephthalate (PET) substrate by DMP-3000 with dimension of 100 µm finger width, 50 µm spacing, and 500 nm thickness. To achieve a high sensitivity and wide sensing range, the active layer of composite thin film was deposited over the IDEs through spin coating to achieve a thickness of ~ 300 nm. The sensor can effective detect relative humidity in range of 0–85% RH with fast response and recovery times of 1 and 2 s respectively that are comparable to high end commercial sensors.

ACS Style

Gul Hassan; Jinho Bae; Chong Hyun Lee; Arshad Hassan. Wide range and stable ink-jet printed humidity sensor based on graphene and zinc oxide nanocomposite. Journal of Materials Science: Materials in Electronics 2018, 29, 5806 -5813.

AMA Style

Gul Hassan, Jinho Bae, Chong Hyun Lee, Arshad Hassan. Wide range and stable ink-jet printed humidity sensor based on graphene and zinc oxide nanocomposite. Journal of Materials Science: Materials in Electronics. 2018; 29 (7):5806-5813.

Chicago/Turabian Style

Gul Hassan; Jinho Bae; Chong Hyun Lee; Arshad Hassan. 2018. "Wide range and stable ink-jet printed humidity sensor based on graphene and zinc oxide nanocomposite." Journal of Materials Science: Materials in Electronics 29, no. 7: 5806-5813.

Journal article
Published: 18 December 2017 in Sensors
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In this paper, a compact microstrip feed inset patch sensor is proposed for measuring the salinities in seawater. The working principle of the proposed sensor depends on the fact that different salinities in liquid have different relative permittivities and cause different resonance frequencies. The proposed sensor can obtain better sensitivity to salinity changes than common sensors using conductivity change, since the relative permittivity change to salinity is 2.5 times more sensitive than the conductivity change. The patch and ground plane of the proposed sensor are fabricated by conductive copper spray coating on the masks made by 3D printer. The fabricated patch and the ground plane are bonded to a commercial silicon substrate and then attached to 5 mm-high chamber made by 3D printer so that it contains only 1 mL seawater. For easy fabrication and testing, the maximum resonance frequency was selected under 3 GHz and to cover salinities in real seawater, it was assumed that the salinity changes from 20 to 35 ppt. The sensor was designed by the finite element method-based ANSYS high-frequency structure simulator (HFSS), and it can detect the salinity with 0.01 ppt resolution. The designed sensor has a resonance frequency separation of 37.9 kHz and reflection coefficients under −20 dB at the resonant frequencies. The fabricated sensor showed better performance with average frequency separation of 48 kHz and maximum reflection coefficient of −35 dB. By comparing with the existing sensors, the proposed compact and low-cost sensor showed a better detection capability. Therefore, the proposed patch sensor can be utilized in radio frequency (RF) tunable sensors for salinity determination.

ACS Style

Kibae Lee; Arshad Hassan; Chong Hyun Lee; Jinho Bae. Microstrip Patch Sensor for Salinity Determination. Sensors 2017, 17, 2941 .

AMA Style

Kibae Lee, Arshad Hassan, Chong Hyun Lee, Jinho Bae. Microstrip Patch Sensor for Salinity Determination. Sensors. 2017; 17 (12):2941.

Chicago/Turabian Style

Kibae Lee; Arshad Hassan; Chong Hyun Lee; Jinho Bae. 2017. "Microstrip Patch Sensor for Salinity Determination." Sensors 17, no. 12: 2941.

Journal article
Published: 01 December 2017 in Sensors and Actuators A: Physical
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ACS Style

Arshad Hassan; Kibae Lee; Jinho Bae; Chong Hyun Lee. An inkjet-printed microstrip patch sensor for liquid identification. Sensors and Actuators A: Physical 2017, 268, 141 -147.

AMA Style

Arshad Hassan, Kibae Lee, Jinho Bae, Chong Hyun Lee. An inkjet-printed microstrip patch sensor for liquid identification. Sensors and Actuators A: Physical. 2017; 268 ():141-147.

Chicago/Turabian Style

Arshad Hassan; Kibae Lee; Jinho Bae; Chong Hyun Lee. 2017. "An inkjet-printed microstrip patch sensor for liquid identification." Sensors and Actuators A: Physical 268, no. : 141-147.

Journal article
Published: 01 December 2017 in Organic Electronics
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ACS Style

Shawkat Ali; Arshad Hassan; Gul Hassan; Jinho Bae; Chong Hyun Lee. Flexible frequency selective passive circuits based on memristor and capacitor. Organic Electronics 2017, 51, 119 -127.

AMA Style

Shawkat Ali, Arshad Hassan, Gul Hassan, Jinho Bae, Chong Hyun Lee. Flexible frequency selective passive circuits based on memristor and capacitor. Organic Electronics. 2017; 51 ():119-127.

Chicago/Turabian Style

Shawkat Ali; Arshad Hassan; Gul Hassan; Jinho Bae; Chong Hyun Lee. 2017. "Flexible frequency selective passive circuits based on memristor and capacitor." Organic Electronics 51, no. : 119-127.

Article
Published: 27 September 2017 in Journal of Materials Science: Materials in Electronics
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In recent, silver (Ag) nanowires (NWs) have received much attention as an alternative to indium tin oxide (ITO) for transparent electrode application in printed and transparent electronics. However, Ag NWs have its breakup problem by joule heating during current. To overcome this problem, this paper demonstrates a mesh type electrode based on Ag nanoparticles, which is fabricated on PET substrate through an ink-jet printing technique. The proposed electrode has a low resistance of 108.5 Ω/sq and a good optical transparency around 92% at 300–800 nm. It has a relationship that the sheet resistance drops with the decrease of transparency due to depending hole size and the best curing temperature is found to be 120 °C. It also demonstrate an excellent flexible stability, showing < 2% resistance change after over 100 bending cycles. These resistance and transparency are similar with that of commercially ITO electrode, and are superior to other alternatives such as carbon nanotube electrodes. The proposed electrode can be considered as a commercial electrode to as an alternative to ITO electrode.

ACS Style

Gul Hassan; Jinho Bae; Chong Hyun Lee. Ink-jet printed transparent and flexible electrodes based on silver nanoparticles. Journal of Materials Science: Materials in Electronics 2017, 29, 49 -55.

AMA Style

Gul Hassan, Jinho Bae, Chong Hyun Lee. Ink-jet printed transparent and flexible electrodes based on silver nanoparticles. Journal of Materials Science: Materials in Electronics. 2017; 29 (1):49-55.

Chicago/Turabian Style

Gul Hassan; Jinho Bae; Chong Hyun Lee. 2017. "Ink-jet printed transparent and flexible electrodes based on silver nanoparticles." Journal of Materials Science: Materials in Electronics 29, no. 1: 49-55.

Abstract
Published: 01 May 2017 in The Journal of the Acoustical Society of America
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A conventional parametric array (PA) loudspeaker has a relatively small aperture and produces a highly directional audible sound beam. Due to limitations arising from their size and power consumption, standard PA loudspeakers are not used in mobile devices. PA loudspeakers are typically larger than 25 cm and require more than 60 W. We show that piezoelectric micro-machined ultrasonic transducer (pMUT) arrays can emit highly directional ultrasonic sounds with a power efficiency of up to 80% [Je and Moon, Ultrasonics 53, 1124-1134 (2014)]. Highly directional sound beams with a frequency bandwidth of 13 kHz can be generated efficiently by pMUT arrays with two resonant frequencies [Je and Moon, JASA 173(4), 1732-1743 (2015)]. We used a signal processor, power amplifier, and pMUT array to build a loudspeakersystem that is smaller than, and requires less power than, a conventional PA loudspeakersystem. In our loudspeakersystem, the maximum sound pressure level (SPL) is 75 dB, ± 3 dB frequency bandwidth is 12.5 kHz, and the total power consumption is 3.4 W. Hence, this loudspeakersystem could potentially be used in mobile devices. [This work was supported by Samsung Research Funding Center, SRFC-IT1404-00.]

ACS Style

Kyounghun Been; Hongmin Ahn; Jin-Young Kim; In-Dong Kim; Joung Hoa Kim; Gibae Lee; Jinho Bae; Chong Hyun Lee; Wonkyu Moon. Feasibility study on a highly-directional parametric array loudspeaker applicable to mobile devices. The Journal of the Acoustical Society of America 2017, 141, 4017 -4017.

AMA Style

Kyounghun Been, Hongmin Ahn, Jin-Young Kim, In-Dong Kim, Joung Hoa Kim, Gibae Lee, Jinho Bae, Chong Hyun Lee, Wonkyu Moon. Feasibility study on a highly-directional parametric array loudspeaker applicable to mobile devices. The Journal of the Acoustical Society of America. 2017; 141 (5):4017-4017.

Chicago/Turabian Style

Kyounghun Been; Hongmin Ahn; Jin-Young Kim; In-Dong Kim; Joung Hoa Kim; Gibae Lee; Jinho Bae; Chong Hyun Lee; Wonkyu Moon. 2017. "Feasibility study on a highly-directional parametric array loudspeaker applicable to mobile devices." The Journal of the Acoustical Society of America 141, no. 5: 4017-4017.

Conference paper
Published: 23 April 2017 in 25th International Conference on Optical Fiber Sensors
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In various optical sensor applications, programmable analog filters are desirable to reduce the hardware requirement. Memristor is two state programmable nonvolatile resistor, which has a small size and low power consumption. Using these resistance switching characteristics of a memristor, we propose a novel memristor-capacitor (MC) based printed low pass and high pass filters for analog circuits to achieve tunable cut-off frequencies and bandwidth. The cut-off frequencies of filters are controlled through a memristor state switching (HRS/LRS), whereas the capacitor has a fixed value. The proposed MC filters utilize graphene/poly 4-vinlyphenol (G/PVP) for dielectric layer of capacitors and Graphene Quatum Dots (GQDs)/PVP for an active layer of memristor, and these layers are fabricated on ITO coated flexible PET substrate through electrohydrodynamic (EHD) technique. Both MC filters are designed as parameters of two state memristance and a capacitance. From comparison between designed and fabricated filters, we show that they are matched quite well. © (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

ACS Style

Shawkat Ali; Arshad Hassan; Gul Hassan; Jinho Bae; Chong Hyun Lee. Memristor-capacitor passive filters to tune both cut-off frequency and bandwidth. 25th International Conference on Optical Fiber Sensors 2017, 10323, 1032379 .

AMA Style

Shawkat Ali, Arshad Hassan, Gul Hassan, Jinho Bae, Chong Hyun Lee. Memristor-capacitor passive filters to tune both cut-off frequency and bandwidth. 25th International Conference on Optical Fiber Sensors. 2017; 10323 ():1032379.

Chicago/Turabian Style

Shawkat Ali; Arshad Hassan; Gul Hassan; Jinho Bae; Chong Hyun Lee. 2017. "Memristor-capacitor passive filters to tune both cut-off frequency and bandwidth." 25th International Conference on Optical Fiber Sensors 10323, no. : 1032379.

Journal article
Published: 04 April 2017 in Nanotechnology
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Recently, many researchers have been paying attention to nanogenerators (NGs) as energy sources for self-powered mirco-nano systems, and studying how to achieve their higher power generation. Hence, we propose a hybrid-type NG for harvesting both the piezoelectric and triboelectric effect simultaneously. In the proposed hybrid NG, the piezoelectric NG (PNG) and triboelectric NG (TENG) are fabricated using polydimethylsiloxane (PDMS) and perovskite zinc stannite (ZnSnO3) nanocubes with a high charge polarization of 59 uC cm−2 composite (PDMS + ZnSnO3) and UV surface-treated PDMS, respectively. To effectively combine a high output current of PNG and a high voltage of TENG, these two NGs are stacked upon each other, and separated by sponge spacers providing a uniform air gap for the triboelectric effect. In particular, this fabricated structure has a low Young's modulus for piezoelectricity. The proposed hybrid NG device effectively achieves a combined peak voltage of 300 V on an open circuit, a power density of 10.41 mW cm−2 at 1 MΩ load, and a maximum short circuit current density of 16 mA cm−2 at 50 Ω load. It is feasible that the proposed NG can be utilized as a source for various self-powered systems.

ACS Style

Gul Hassan; Fasihullah Khan; Arshad Hassan; Shawkat Ali; Jinho Bae; Chong Hyun Lee. A flat-panel-shaped hybrid piezo/triboelectric nanogenerator for ambient energy harvesting. Nanotechnology 2017, 28, 175402 .

AMA Style

Gul Hassan, Fasihullah Khan, Arshad Hassan, Shawkat Ali, Jinho Bae, Chong Hyun Lee. A flat-panel-shaped hybrid piezo/triboelectric nanogenerator for ambient energy harvesting. Nanotechnology. 2017; 28 (17):175402.

Chicago/Turabian Style

Gul Hassan; Fasihullah Khan; Arshad Hassan; Shawkat Ali; Jinho Bae; Chong Hyun Lee. 2017. "A flat-panel-shaped hybrid piezo/triboelectric nanogenerator for ambient energy harvesting." Nanotechnology 28, no. 17: 175402.

Article
Published: 17 March 2017 in Applied Physics A
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To obtain a desired performance of non-volatile memory applications, heterojunction-based resistive switching devices have tremendous attractions. In this paper, we demonstrate resistive switching characteristics for heterojunction of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/poly(4-vinylphenol) (PVP) composite and methyl red sandwiched in between bottom and top silver (Ag) electrodes. The proposed heterojunction layers are fabricated through spin coater at 3000 rpm for 60 s each, and the Ag electrodes are deposited through a commercialized inkjet printer DMP-3000 on polyethyleneterephthalate (PET) substrate. To verify the proposed device, the resistive switching on dual polarity voltage of ±10.2 V is measured over more than 500 endurance cycles. The paper also presents an Roff/Ron ratio which can adjust through an active layer’s area and a blending ratio of the PEDOT:PSS and PVP. By applying the area of 100 μm2 and the blending ratio of 3:1, we achieve the higher Roff/Ron ratio of 121, and its high resistance state (HRS) and low resistance state (LRS) are observed as 3000 kΩ and 24.7 kΩ, respectively. To maintain a long retention time, the device is encapsulated with PDMS, which changes a little variations of 52 Ω for HRS 498 Ω for LRS over 60 days. For the flexible realization to be utilized in wearable applications, it can be easily applied on a plastic substrate using printed technologies.

ACS Style

Gul Hassan; Shawkat Ali; Jinho Bae; Chong Hyun Lee. Flexible resistive switching device based on poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/poly(4-vinylphenol) (PVP) composite and methyl red heterojunction. Applied Physics A 2017, 123, 256 .

AMA Style

Gul Hassan, Shawkat Ali, Jinho Bae, Chong Hyun Lee. Flexible resistive switching device based on poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/poly(4-vinylphenol) (PVP) composite and methyl red heterojunction. Applied Physics A. 2017; 123 (4):256.

Chicago/Turabian Style

Gul Hassan; Shawkat Ali; Jinho Bae; Chong Hyun Lee. 2017. "Flexible resistive switching device based on poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/poly(4-vinylphenol) (PVP) composite and methyl red heterojunction." Applied Physics A 123, no. 4: 256.

Journal article
Published: 28 February 2017 in IEIE Transactions on Smart Processing & Computing
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Jeehyun Lee; Jihoon Kwon; Jin-Ho Bae; Chong Hyun Lee. Classification Algorithms for Human and Dog Movement Based on Micro-Doppler Signals. IEIE Transactions on Smart Processing & Computing 2017, 6, 10 -17.

AMA Style

Jeehyun Lee, Jihoon Kwon, Jin-Ho Bae, Chong Hyun Lee. Classification Algorithms for Human and Dog Movement Based on Micro-Doppler Signals. IEIE Transactions on Smart Processing & Computing. 2017; 6 (1):10-17.

Chicago/Turabian Style

Jeehyun Lee; Jihoon Kwon; Jin-Ho Bae; Chong Hyun Lee. 2017. "Classification Algorithms for Human and Dog Movement Based on Micro-Doppler Signals." IEIE Transactions on Smart Processing & Computing 6, no. 1: 10-17.

Journal article
Published: 01 February 2017 in Organic Electronics
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Shawkat Ali; Jinho Bae; Chong Hyun Lee; Sangho Shin; Nobuhiko P. Kobayashi. Ultra-low power non-volatile resistive crossbar memory based on pull up resistors. Organic Electronics 2017, 41, 73 -78.

AMA Style

Shawkat Ali, Jinho Bae, Chong Hyun Lee, Sangho Shin, Nobuhiko P. Kobayashi. Ultra-low power non-volatile resistive crossbar memory based on pull up resistors. Organic Electronics. 2017; 41 ():73-78.

Chicago/Turabian Style

Shawkat Ali; Jinho Bae; Chong Hyun Lee; Sangho Shin; Nobuhiko P. Kobayashi. 2017. "Ultra-low power non-volatile resistive crossbar memory based on pull up resistors." Organic Electronics 41, no. : 73-78.

Journal article
Published: 25 January 2017 in Journal of the Institute of Electronics and Information Engineers
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Kibae Lee; Juho Kim; Chong Hyun Lee; Jinho Bae; Jaeil Lee; Jung Hong Cho. Seabed Sediment Feature Extraction Algorithm using Attenuation Coefficient Variation According to Frequency. Journal of the Institute of Electronics and Information Engineers 2017, 54, 111 -120.

AMA Style

Kibae Lee, Juho Kim, Chong Hyun Lee, Jinho Bae, Jaeil Lee, Jung Hong Cho. Seabed Sediment Feature Extraction Algorithm using Attenuation Coefficient Variation According to Frequency. Journal of the Institute of Electronics and Information Engineers. 2017; 54 (1):111-120.

Chicago/Turabian Style

Kibae Lee; Juho Kim; Chong Hyun Lee; Jinho Bae; Jaeil Lee; Jung Hong Cho. 2017. "Seabed Sediment Feature Extraction Algorithm using Attenuation Coefficient Variation According to Frequency." Journal of the Institute of Electronics and Information Engineers 54, no. 1: 111-120.