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| WoS | SCOPUS | Document Type | Document Title | Abstract | Authors | Affiliation | ResearcherID (WoS) | AuthorsID (SCOPUS) | Author Email(s) | Journal Name | JCR Abbreviation | ISSN | eISSN | Volume | Issue | WoS Edition | WoS Category | JCR Year | IF | JCR (%) | FWCI | FWCI Update Date | WoS Citation | SCOPUS Citation | Keywords (WoS) | KeywordsPlus (WoS) | Keywords (SCOPUS) | KeywordsPlus (SCOPUS) | Language | Publication Stage | Publication Year | Publication Date | DOI | JCR Link | DOI Link | WOS Link | SCOPUS Link |
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| ○ | ○ | Article | BBR-ACD: BBR with Advanced Congestion Detection | With the aim of improved throughput with reduced delay, Google proposed the bottleneck bandwidth and round-trip time (BBR) congestion control algorithm in 2016. Contrasting with the traditional loss-based congestion control algorithms, it operates without bottleneck queue formation and packet losses. However, we find unexpected behaviour in BBR during testbed experiments and network simulator 3 (NS-3) simulations. We observe huge packet losses, retransmissions, and large queue formation in the bottleneck in a congested network scenario. We believe this is because of BBR's nature of sending extra data during the bandwidth probing without considering the network conditions, and the lack of a proper recovery mechanism. In a congested network, the sent extra data creates a large queue in the bottleneck, which is sustained due to insufficient drain time. BBR lacks a proper mechanism to detect such large bottleneck queues, cannot comply with the critical congestion situation properly, and results in excessive retransmission problems. Based on these observations, we propose a derivative of BBR, called "BBR with advanced congestion detection (BBR-ACD)", that reduces the excessive retransmissions without losing the merits. We propose a novel method to determine an actual congestion situation by considering the packet loss and delay-gradient of round-trip time, and implement a proper recovery mechanism to handle such a congestion situation. Through extensive test and NS-3 simulations, we confirmed that the proposed BBR-ACD could reduce the retransmissions by about 50% while improving the total goodput of the network. | Mahmud, Imtiaz; Kim, Geon-Hwan; Lubna, Tabassum; Cho, You-Ze | Kyungpook Natl Univ, Sch Elect Engn, Daegu 41566, South Korea | Mahmud, Imtiaz/R-1089-2019 | 56203487900; 57189040274; 57205303733; 7404469829 | imtiaz.tee@gmail.com;kgh76@ee.knu.ac.kr;juthy.cse@gmail.com;yzcho@ee.knu.ac.kr; | ELECTRONICS | ELECTRONICS-SWITZ | 2079-9292 | 9 | 1 | SCIE | COMPUTER SCIENCE, INFORMATION SYSTEMS;ENGINEERING, ELECTRICAL & ELECTRONIC;PHYSICS, APPLIED | 2020 | 2.397 | 52.9 | 1.15 | 2025-06-25 | 17 | 24 | BBR; congestion control; actual congestion detection; retransmissions; TCP | POWER | Actual congestion detection; BBR; Congestion control; Retransmissions; TCP | English | 2020 | 2020-01 | 10.3390/electronics9010136 | 바로가기 | 바로가기 | 바로가기 | 바로가기 | |||
| ○ | ○ | Article | BBR-CWS: Improving the Inter-Protocol Fairness of BBR | TCP congestion control adjusts the sending rate in order to protect Internet from the continuous traffic and ensure fair coexistence among multiple flows. Especially, loss-based congestion control algorithms were mainly used, which worked relatively well for past Internet with low bandwidth and small bottleneck buffer size. However, the modern Internet uses considerably more sophisticated network equipment and advanced transmission technologies, and loss-based congestion control can cause performance degradation due to excessive queueing delay and packet loss. Therefore, Google introduced a new congestion control in 2016, Bottleneck Bandwidth Round-trip propagation time (BBR). In contrast with traditional congestion control, BBR tries to operate at the Kleinrock's optimal operating point, where delivery rate is maximized and latency is minimized. However, when BBR and loss-based congestion control algorithms coexist on the same bottleneck link, most of bottleneck bandwidth is occupied by flows that use a particular algorithm, and excessive packet retransmission can occur. Therefore, this paper proposes a BBR congestion window scaling (BBR-CWS) scheme to improve BBR's inter-protocol fairness with a loss-based congestion control algorithm. Through Mininet experiment results, we confirmed that fairness between BBR-CWS and CUBIC improved up to 73% and has the value of 0.9 or higher in most bottleneck buffer environments. Moreover, the number of packet retransmissions was reduced by up to 96%, compared to the original BBR. | Song, Yeong-Jun; Kim, Geon-Hwan; Cho, You-Ze | Kyungpook Natl Univ, Sch Elect Engn, Daegu 41556, South Korea | 57210919165; 57189040274; 7404469829 | syj5385@knu.ac.kr;kgh76@ee.knu.ac.kr;yzcho@ee.knu.ac.kr; | ELECTRONICS | ELECTRONICS-SWITZ | 2079-9292 | 9 | 5 | SCIE | COMPUTER SCIENCE, INFORMATION SYSTEMS;ENGINEERING, ELECTRICAL & ELECTRONIC;PHYSICS, APPLIED | 2020 | 2.397 | 52.9 | 0.95 | 2025-06-25 | 12 | 18 | TCP congestion control; BBR; CUBIC; inter-protocol fairness; retransmission | CONGESTION CONTROL; TCP BBR | BBR; CUBIC; Inter-protocol fairness; Retransmission; TCP congestion control | English | 2020 | 2020-05 | 10.3390/electronics9050862 | 바로가기 | 바로가기 | 바로가기 | 바로가기 | ||||
| ○ | ○ | Article | CoAP-Based Streaming Control for IoT Applications | The Constrained Application Protocol (CoAP) is a representative messaging protocol for Internet of Things (IoT) applications. It is noted that a lot of IoT-based streaming applications have been recently deployed. Typically, CoAP uses User Datagram Protocol (UDP) as its underlying protocol for lightweight messaging. However, it cannot provide reliability, since it is based on UDP. Thus, the CoAP over Transmission Control Protocol (TCP) was recently proposed so as to provide reliability. However, the existing schemes do not provide the error handling and flow controls suitably for IoT-based streaming applications. This tends to induce throughput degradation in wireless lossy networks. In this paper, we propose a CoAP-based streaming control (CoAP-SC) scheme, which is an extension of CoAP over UDP with error handling and flow control for throughput enhancement. The proposed CoAP-SC scheme is designed by considering the sequence number of data message, the use of ACK messages, and the buffer size of sending buffer. To do this, a new CoAP option is defined. For performance analysis, the proposed scheme is implemented and compared with the existing schemes. From the testbed experimentations in various network environments, we see that the proposed CoAP-SC scheme can provide better throughput than the existing CoAP-based schemes by performing the error handling and flow control operations effectively. | Jung, Joong-Hwa; Gohar, Moneeb; Koh, Seok-Joo | Kyungpook Natl Univ, Sch Comp Sci & Engn, Daegu 41566, South Korea; Bahria Univ, Dept Comp Sci, Islamabad 44000, Pakistan | 57194055389; 36104105300; 8958394800 | godopu16@gmail.com;moneebgohar@gmail.com;sjkoh@knu.ac.kr; | ELECTRONICS | ELECTRONICS-SWITZ | 2079-9292 | 9 | 8 | SCIE | COMPUTER SCIENCE, INFORMATION SYSTEMS;ENGINEERING, ELECTRICAL & ELECTRONIC;PHYSICS, APPLIED | 2020 | 2.397 | 52.9 | 0.34 | 2025-06-25 | 6 | 11 | CoAP; error handling; flow control; IoT; streaming control | CoAP; Error handling; Flow control; IoT; Streaming control | English | 2020 | 2020-08 | 10.3390/electronics9081320 | 바로가기 | 바로가기 | 바로가기 | 바로가기 | |||||
| ○ | ○ | Article | Compact Planar Super-Wideband Monopole Antenna with Four Notched Bands | A compact-sized planar super-wideband (SWB) monopole antenna with four notched bands is presented in this paper. The antenna consists of a rectangular ground plane and a circular radiator that is fed by a tapered microstrip feed line. The overall size of the antenna is 18 mm x 12 mm x 0.5 mm, and its impedance bandwidth (S-11 <= -10 dB) ranges from 2.5 GHz to 40 GHz (bandwidth ratio of 16:1). Four notched bands are obtained using two inverted U-shaped slots, a split-ring resonator (SRR), and a meandered slot. The notched frequency bands can be adjustable by changing the parameters of parasitic slot elements, and the realized notched bands in this paper are Wi-MAX band (3.5 GHz), WLAN band (5.5 GHz), satellite communication X-band (7.5 GHz), and amateur radio band (10.5 GHz). The simulated and experimental results show good agreement with each other. The antenna possesses a high gain, super-wide impedance bandwidth, and omni-directional radiation patterns. | Kumar, Sachin; Lee, Gwan Hui; Kim, Dong Hwi; Haunan, Nashuha Syifa; Choi, Hyun Chul; Kim, Kang Wook | Kyungpook Natl Univ, Sch Elect Engn, Daegu 41566, South Korea | Kumar, Sachin/W-2211-2019 | 56907994000; 57201689364; 56975581300; 57218903778; 57193342681; 57204432422 | gupta.sachin0708@gmail.com;gwan6088@knu.ac.kr;eastsine766@gmail.com;nsh11@knu.ac.kr;hcchoi@ee.knu.ac.kr;kang_kim@ee.knu.ac.kr; | ELECTRONICS | ELECTRONICS-SWITZ | 2079-9292 | 9 | 8 | SCIE | COMPUTER SCIENCE, INFORMATION SYSTEMS;ENGINEERING, ELECTRICAL & ELECTRONIC;PHYSICS, APPLIED | 2020 | 2.397 | 52.9 | 0.81 | 2025-06-25 | 7 | 17 | compact; monopole; notched-band; planar; super-wideband | UWB; DESIGN; PATCH | Compact; Monopole; Notched-band; Planar; Super-wideband | English | 2020 | 2020-08 | 10.3390/electronics9081204 | 바로가기 | 바로가기 | 바로가기 | 바로가기 | |||
| ○ | ○ | Article | Context Aware Video Caption Generation with Consecutive Differentiable Neural Computer | Recent video captioning models aim at describing all events in a long video. However, their event descriptions do not fully exploit the contextual information included in a video because they lack the ability to remember information changes over time. To address this problem, we propose a novel context-aware video captioning model that generates natural language descriptions based on the improved video context understanding. We introduce an external memory, differential neural computer (DNC), to improve video context understanding. DNC naturally learns to use its internal memory for context understanding and also provides contents of its memory as an output for additional connection. By sequentially connecting DNC-based caption models (DNC augmented LSTM) through this memory information, our consecutively connected DNC architecture can understand the context in a video without explicitly searching for event-wise correlation. Our consecutive DNC is sequentially trained with its language model (LSTM) for each video clip to generate context-aware captions with superior quality. In experiments, we demonstrate that our model provides more natural and coherent captions which reflect previous contextual information. Our model also shows superior quantitative performance on video captioning in terms of BLEU (BLEU@4 4.37), METEOR (9.57), and CIDEr-D (28.08). | Kim, Jonghong; Choi, Inchul; Lee, Minho | Kyungpook Natl Univ, Coll IT Engn, Sch Elect Engn, 80 Daehakro, Daegu 41566, South Korea | Lee, Min-Ho/ABE-5735-2021 | 57022250500; 57212005248; 57191730119 | jonghong89@gmail.com;sharpic77@gmail.com;mholee@gmail.com; | ELECTRONICS | ELECTRONICS-SWITZ | 2079-9292 | 9 | 7 | SCIE | COMPUTER SCIENCE, INFORMATION SYSTEMS;ENGINEERING, ELECTRICAL & ELECTRONIC;PHYSICS, APPLIED | 2020 | 2.397 | 52.9 | 0.34 | 2025-06-25 | 5 | 8 | deep neural network; deep learning; context understanding; recurrent neural network; action recognition; memory | Action recognition; Context understanding; Deep learning; Deep neural network; Memory; Recurrent neural network | English | 2020 | 2020-07 | 10.3390/electronics9071162 | 바로가기 | 바로가기 | 바로가기 | 바로가기 | ||||
| ○ | ○ | Article | Deep Neural Network Based Ambient Airflow Control through Spatial Learning | As global energy regulations are strengthened, improving energy efficiency while maintaining performance of electronic appliances is becoming more important. Especially in air conditioning, energy efficiency can be maximized by adaptively controlling the airflow based on detected human locations; however, several limitations such as detection areas, the installation environment, and sensor quantity and real-time performance which come from the constraints in the embedded system make it a challenging problem. In this study, by using a low resolution cost effective vision sensor, the environmental information of living spaces and the real-time locations of humans are learned through a deep learning algorithm to identify the living area from the entire indoor space. Based on this information, we improve the performance and the energy efficiency of air conditioner by smartly controlling the airflow on the identified living area. In experiments, our deep learning based spatial classification algorithm shows error less than +/- 5 degrees. In addition, the target temperature can be reached 19.8% faster and the power consumption can be saved up to 20.5% by the time the target temperature is achieved. | Kim, Sunghak; Choi, InChul; Kim, Dohyeong; Lee, Minho | LG Elect, H&A Control Lab, 84 Wanam Ro, Chang Won 51533, South Korea; Kyungpook Natl Univ, Sch Elect Engn, Coll IT Engn, 80 Daehakro, Daegu 41566, South Korea | Lee, Min-Ho/ABE-5735-2021 | 57216341654; 57212005248; 57222348493; 57191730119 | jay72.kim@lge.com;sharpic77@gmail.com;kimbring2@gmail.com;mholee@gmail.com; | ELECTRONICS | ELECTRONICS-SWITZ | 2079-9292 | 9 | 4 | SCIE | COMPUTER SCIENCE, INFORMATION SYSTEMS;ENGINEERING, ELECTRICAL & ELECTRONIC;PHYSICS, APPLIED | 2020 | 2.397 | 52.9 | 0.34 | 2025-06-25 | 2 | 8 | deep neural network; deep learning; spatial learning; air conditioner; airflow control; smart-care | Air conditioner; Airflow control; Deep learning; Deep neural network; Smart-care; Spatial learning | English | 2020 | 2020-04 | 10.3390/electronics9040591 | 바로가기 | 바로가기 | 바로가기 | 바로가기 | ||||
| ○ | ○ | Article | Design of an Ultra-Wideband Microstrip-to-Slotline Transition on Low-Permittivity Substrate | Analysis and design of an ultra-wideband microstrip-to-slotline transition on a low permittivity substrate is presented. Cross-sectional structures along the proposed transition are analyzed using conformal mapping assuming quasi-TEM modes, attaining one analytical line impedance formula with varying design parameters. Although the slotline is a non-TEM transmission line, the transitional structures are configured to have quasi-TEM modes before forming into the slotline. The line impedance is optimally tapered using the Klopfenstein taper, and the electric field shapes are smoothly transformed from microstrip line to slotline. The analytical formula is accurate within 5% difference, and the final transition configuration can be designed without parameter tuning. The implemented microstrip-to-slotline transition possesses insertion loss of less than 1.5 dB per transition and return loss of more than 10 dB from 4.4 to over 40 GHz. | Lee, Jung Seok; Lee, Gwan Hui; Mohyuddin, Wahab; Choi, Hyun Chul; Kim, Kang Wook | Kyungpook Natl Univ, Sch Elect Engn, Daegu 41566, South Korea; Natl Univ Sci & Technol, Res Inst Microwave & Millimeter Wave Studies, Islamabad 44000, Pakistan | ; Lee, Jung-Seok/L-6826-2019; Mohyuddin, Wahab/ABE-4183-2021 | 57218775544; 57201689364; 56179736900; 57193342681; 57204432422 | j.seok1020@gmail.com;gwan6088@knu.ac.kr;wahab.mohyuddin@seecs.edu.pk;hcchoi@ee.knu.ac.kr;kang_kim@ee.knu.ac.kr; | ELECTRONICS | ELECTRONICS-SWITZ | 2079-9292 | 9 | 8 | SCIE | COMPUTER SCIENCE, INFORMATION SYSTEMS;ENGINEERING, ELECTRICAL & ELECTRONIC;PHYSICS, APPLIED | 2020 | 2.397 | 52.9 | 0.2 | 2025-06-25 | 3 | 4 | transition; microstrip; slotline; ultra-wideband; conformal mapping | LINE | Conformal mapping; Microstrip; Slotline; Transition; Ultra-wideband | English | 2020 | 2020-08 | 10.3390/electronics9081329 | 바로가기 | 바로가기 | 바로가기 | 바로가기 | |||
| ○ | ○ | Article | Developing an Open-Source Lightweight Game Engine with DNN Support | With the growth of artificial intelligence and deep learning technology, we have many active research works to apply the related techniques in various fields. To test and apply the latest machine learning techniques in gaming, it will be very useful to have a light-weight game engine for quick prototyping. Our game engine is implemented in a cost-effective way, in comparison to well-known commercial proprietary game engines, by utilizing open source products. Due to its simple internal architecture, our game engine is especially beneficial for modifying and reviewing the new functions through quick and repetitive tests. In addition, the game engine has a DNN (deep neural network) module, with which the proposed game engine can apply deep learning techniques to the game features, through applying deep learning algorithms in real-time. Our DNN module uses a simple C++ function interface, rather than additional programming languages and/or scripts. This simplicity enables us to apply machine learning techniques more efficiently and casually to the game applications. We also found some technical issues during our development with open sources. These issues mostly occurred while integrating various open source products into a single game engine. We present details of these technical issues and our solutions. | Park, Haechan; Baek, Nakhoon | Kyungpook Natl Univ, Sch Comp Sci & Engn, Daegu 41566, South Korea; Louisiana State Univ, Sch Elect Engn & Comp Sci, Baton Rouge, LA 70803 USA | 57212931500; 7007017954 | lucidsun92@gmail.com;nbaek@knu.ac.kr; | ELECTRONICS | ELECTRONICS-SWITZ | 2079-9292 | 9 | 9 | SCIE | COMPUTER SCIENCE, INFORMATION SYSTEMS;ENGINEERING, ELECTRICAL & ELECTRONIC;PHYSICS, APPLIED | 2020 | 2.397 | 52.9 | 0.2 | 2025-06-25 | 4 | 6 | game engine; open source; artificial intelligence; light-weight; deep neural network; implementation; case study | Artificial intelligence; Case study; Deep neural network; Game engine; Implementation; Light-weight; Open source | English | 2020 | 2020-09 | 10.3390/electronics9091421 | 바로가기 | 바로가기 | 바로가기 | 바로가기 | |||||
| ○ | ○ | Article | Distributed Identifier-Locator Mapping Management in Mobile ILNP Networks | In the Identifier Locator Network Protocol (ILNP) networks, the existing mobility control schemes based on the centralized entity, called the Dynamic Domain Name Service (DDNS) server, such that all the control traffic is processed at the DDNS server. However, the centralized mobility schemes have significant limitations, such as control traffic overhead at the server and large handover delay. In order to resolve these issues, we propose a new mobility control scheme for ILNP networks, which manages the identifier-locators (ID-LOCs) in the fully distributed manner. In our scheme, each domain has a dedicated mobile DDNS (m-DDNS) server at the site border router (SBR). The m-DDNS server maintains two databases; i.e., home host register (HHR) and visiting host register (VHR), to support the roaming of mobile hosts. When a mobile host roams into a domain, the m-DDNS server in the visiting domain registers the host's ID-LOC in the VHR and requests the update of HHR to the m-DDNS server in the home domain. Since the m-DDNS servers communicate each other directly, the ID-LOC mappings are managed without involvement of any central entities. We analyzed our proposed mobility scheme via numerical analysis and compared its performance with those of existing schemes. Numerical results showed that our scheme outperforms the existing mobility control schemes substantially in terms of control traffic overhead at the servers, total transmission delay and handover delay. | Gohar, Moneeb; Choi, Jin-Ghoo; Ahmed, Waleed; Rahman, Arif Ur; Muzammal, Muhammad; Koh, Seok-Joo | Bahria Univ, Dept Comp Sci, Islamabad 44000, Pakistan; Yeungnam Univ, Dept Informat & Commun Engn, Gyongsan 38541, South Korea; Univ Poonch, Dept Elect Engn, Rawalkot 12350, Pakistan; Kyungpook Natl Univ, Dept Comp Sci & Engn, Daegu 41566, South Korea | Muzammal, Muhammad/AAE-8185-2022; Rahman, Arif/M-6995-2019; Ahmed, Waleed/JJD-3429-2023 | 36104105300; 7501394023; 57208163571; 57022909600; 36677704900; 8958394800 | moneebgohar@gmail.com;jchoi@yu.ac.kr;drwaleedahmad@upr.edu.pk;badwanpk@gmail.com;muzammal.muhammad@gmail.com;sjkoh@knu.ac.kr; | ELECTRONICS | ELECTRONICS-SWITZ | 2079-9292 | 9 | 1 | SCIE | COMPUTER SCIENCE, INFORMATION SYSTEMS;ENGINEERING, ELECTRICAL & ELECTRONIC;PHYSICS, APPLIED | 2020 | 2.397 | 52.9 | 0.07 | 2025-06-25 | 1 | 1 | ILNP; mobility management; identifier-locator; mobile network; roaming | Identifier-locator; ILNP; Mobile network; Mobility management; Roaming | English | 2020 | 2020-01 | 10.3390/electronics9010058 | 바로가기 | 바로가기 | 바로가기 | 바로가기 | ||||
| ○ | ○ | Article | Effect of Link Misalignment in the Optical-Internet of Underwater Things | Underwater wireless optical communication (UWOC) enables high-speed links in water for the optical Internet of Underwater Things (O-IoUT) networks. O-IoUT provides various marine applications, including ocean exploration, environmental monitoring, and underwater navigation. O-IoUT typically utilizes light-emitting diodes (LEDs) and different laser diodes (LDs) such as green/blue lasers to achieve efficient data communication in the underwater environment. The high-speed optical communication is limited up to a few tens of meters due to underwater channel impairments and misalignment between the transmitter (Tx) and the receiver (Rx). UWOC provides high-speed communications only in the line of sight conditions, and a small misalignment between the Tx and the Rx can degrade the system performance. In an attempt to understand and minimize this misalignment issue, we investigate how received power in a UWOC system depends on the transmitted beam's divergence angle. Simulation results are provided to show the effectiveness of the study by comparing the plane, Gaussian, and spherical beams. Monte Carlo simulations are utilized to determine the maximum allowable lateral offset between Tx and Rx for a given Tx divergence angle. The results provide an overview and design-based trade-off between different parameters such as lateral offset, the power received, and bandwidth of the channel. The proposed method improves not only the maximum allowed link-span but also the bandwidth of the channel for a given transmission distance. | Khalil, Ruhul Amin; Babar, Mohammad Inayatullah; Saeed, Nasir; Jan, Tariqullah; Cho, Ho-Shin | Univ Engn & Technol, Dept Elect Engn, Fac Elect & Comp Engn, Peshawar 25120, Pakistan; King Abdullah Univ Sci & Technol, Comp Elect & Math Sci & Engn CEMSE Div, Thuwal 23955, Saudi Arabia; Kyungpook Natl Univ, Sch Elect Engn, Daegu 41566, South Korea | Khalil, Ruhul Amin/AAQ-2621-2020; Saeed, Nasir/Y-5724-2019 | 55546442400; 36681911000; 56622571900; 56567769400; 35316924900 | ruhulamin@uetpeshawar.edu.pk;babar@uetpeshawar.edu.pk;mr.nasir.saeed@ieee.org;tariqullahjan@uetpeshawar.edu.pk;hscho@ee.knu.ac.kr; | ELECTRONICS | ELECTRONICS-SWITZ | 2079-9292 | 9 | 4 | SCIE | COMPUTER SCIENCE, INFORMATION SYSTEMS;ENGINEERING, ELECTRICAL & ELECTRONIC;PHYSICS, APPLIED | 2020 | 2.397 | 52.9 | 1.22 | 2025-06-25 | 22 | 25 | underwater wireless optical communication (UWOC); misalignment; Line-of-Sight (LOS); Monte-Carlo simulations | WIRELESS COMMUNICATIONS; GAUSSIAN-BEAM; COMMUNICATION; PROPAGATION; PERFORMANCE; CHANNEL | Line-of-Sight (LOS); Misalignment; Monte-Carlo simulations; Underwater wireless optical communication (UWOC) | English | 2020 | 2020-04 | 10.3390/electronics9040646 | 바로가기 | 바로가기 | 바로가기 | 바로가기 | |||
| ○ | ○ | Article | Effect of Mg Doping on the Electrical Performance of a Sol-Gel-Processed SnO2 Thin-Film Transistor | Sol-gel-processed Mg-doped SnO2 thin-film transistors (TFTs) were successfully fabricated. The effect of Mg concentration on the structural, chemical, and optical properties of thin films and the corresponding TFT devices was investigated. The results indicated that an optimal Mg concentration yielded an improved negative bias stability and increased optical band gap, resulting in transparent devices. Furthermore, the optimal device performance was obtained with 0.5 wt% Mg. The fabricated 0.5 wt% Mg-doped SnO2 TFT was characterized by a field effect mobility, a subthreshold swing, and I-on/I-off ratio of 4.23 cm(2)/Vs, 1.37 V/decade, and similar to 1 x 10(7), respectively. The added Mg suppressed oxygen-vacancy formation, thereby improving the bias stability. This work may pave the way for the development of alkaline-earth-metal-doped SnO2-based thin-film devices. | Lee, Won-Yong; Lee, Hyunjae; Ha, Seunghyun; Lee, Changmin; Bae, Jin-Hyuk; Kang, In-Man; Kim, Kwangeun; Jang, Jaewon | Kyungpook Natl Univ, Sch Elect Engn, Daegu 41566, South Korea; Hongik Univ, Dept Elect & Elect Convergence Engn, Sejong 30016, South Korea | 57209527128; 26638774100; 57209074248; 57191709616; 35326180700; 7203062678; 36004977500; 57194107504 | yongsz@knu.ac.kr;fospm22@knu.ac.kr;neilsatriani@knu.ac.kr;lcm1684@knu.ac.kr;jhbae@ee.knu.ac.kr;imkang@ee.knu.ac.kr;kim@hongik.ac.kr;j1jang@knu.ac.kr; | ELECTRONICS | ELECTRONICS-SWITZ | 2079-9292 | 9 | 3 | SCIE | COMPUTER SCIENCE, INFORMATION SYSTEMS;ENGINEERING, ELECTRICAL & ELECTRONIC;PHYSICS, APPLIED | 2020 | 2.397 | 52.9 | 0.95 | 2025-06-25 | 17 | 20 | sol-gel process; thin-film transistor; SnO2; Mg doping; negative bias stability | Mg doping; Negative bias stability; Sno<sub>2</sub> ; Sol-gel process; Thin-film transistor | English | 2020 | 2020-03 | 10.3390/electronics9030523 | 바로가기 | 바로가기 | 바로가기 | 바로가기 | |||||
| ○ | ○ | Article | Framework of IoT Services over Unidirectional Visible Lights Communication Networks | Visible Light Communication (VLC) has been noted as an emerging technology for communications in wireless local area networks. VLC provides some distinctive features over the conventional wireless access technologies, such as Wi-Fi, Bluetooth, or ZigBee. The most prominent feature of VLC is that it can provide more exact location information, since it is based on a particular light. In addition, VLC can reduce the frequency interferences from numerous wireless channels, since it uses a completely different radio frequency channel from the conventional wireless access technologies. Thus, VLC can be used for Internet-of-Things (IoT) services. Nevertheless, up to now, not enough studies on how to provide IoT services over VLC networks have been conducted. In this paper, we propose a framework to provide IoT services in VLC networks. In particular, we will consider the unidirectional VLC network, in which the downlink channel from the VLC transmitter to the VLC receiver is given by using VLC communication, whereas the uplink channel from the VLC receiver to the VLC transmitter is implemented by using another wireless access technology, such as Wi-Fi. This is because most of the VLC receivers, such as mobile phones, cannot support the uplink VLC communication. Based on the framework of IoT services over unidirectional VLC, in this paper, we also propose the VLC-IoT protocol (VIP) which is an application layer protocol for data transport with the session management functionality that can be used to effectively provide IoT services among IoT servers, VLC transmitters and VLC receivers in the networks. The proposed VIP protocol is implemented by using the Cooja simulator. For performance analysis, the proposed scheme is compared with the existing CoAP-based scheme that does not provide the session management. From a variety of simulation experiments, we see that the proposed scheme can provide lower data transmission and handover delays, compared to the existing scheme. | Kim, So-Yong; Kim, Cheol-Min; Koh, Seok-Joo | Kyungpook Natl Univ, Sch Comp Sci & Engn, Daegu 41566, South Korea | ; Kim, So-Yong/JJG-1016-2023 | 57218590446; 57191517764; 8958394800 | thdyd324@gmail.com;cheolminkim@vanilet.pe.kr;sjkoh@knu.ac.kr; | ELECTRONICS | ELECTRONICS-SWITZ | 2079-9292 | 9 | 9 | SCIE | COMPUTER SCIENCE, INFORMATION SYSTEMS;ENGINEERING, ELECTRICAL & ELECTRONIC;PHYSICS, APPLIED | 2020 | 2.397 | 52.9 | 0.54 | 2025-06-25 | 7 | 8 | VLC; IoT; uni-directional VLC; framework; session management; simulation | Framework; IoT; Session management; Simulation; Uni-directional VLC; VLC | English | 2020 | 2020-09 | 10.3390/electronics9091349 | 바로가기 | 바로가기 | 바로가기 | 바로가기 | ||||
| ○ | ○ | Article | Fuzzy Analytic Hierarchy Process-Based Mobile Robot Path Planning | This study presents a new path planning method based on Fuzzy Analytic Hierarchy Process (FAHP) for a mobile robot to be effectively operated through a multi-objective decision making problem. Unlike typical AHP, the proposed FAHP has a difference in using triangulation fuzzy number based extent analysis to derive weight vectors among the considerations. FAHP framework for finding the optimal position in this study is defined with the highest level (goal), middle level (objectives), and the lowest level (alternatives). It analytically selects an optimal position as a sub-goal among points on the sensing boundary of the mobile robot considering the three objectives: the travel distance to the target, robot's rotation, and safety against collision between obstacles. Alternative solutions are evaluated by quantifying the relative importance for the objectives. Comparative results obtained from the artificial potential field, AHP, and FAHP simulations show that FAHP is much preferable for mobile robot's path planning than typical AHP. | Kim, Changwon; Kim, Yeesock; Yi, Hak | Korea Inst Machinery & Mat, Daegu Res Ctr Med Devices & Rehab, Daejon 305343, South Korea; Calif Baptist Univ, Gordon & Jill Bourns Coll Engn, Riverside, CA 92504 USA; Kyungpook Natl Univ, Sch Mech Engn, Daegu 41566, South Korea | 57199972728; 24450845400; 56567311000 | cwkim@kimm.re.kr;yekim@calbaptist.edu;yihak@knu.ac.kr; | ELECTRONICS | ELECTRONICS-SWITZ | 2079-9292 | 9 | 2 | SCIE | COMPUTER SCIENCE, INFORMATION SYSTEMS;ENGINEERING, ELECTRICAL & ELECTRONIC;PHYSICS, APPLIED | 2020 | 2.397 | 52.9 | 1.22 | 2025-06-25 | 28 | 30 | fuzzy based AHP (FAHP); multi-objective decision making; path planning; mobile robot | AHP; OPTIMIZATION; NAVIGATION | Fuzzy based AHP (FAHP); Mobile robot; Multi-objective decision making; Path planning | English | 2020 | 2020-02 | 10.3390/electronics9020290 | 바로가기 | 바로가기 | 바로가기 | 바로가기 | ||||
| ○ | ○ | Article | Gallium Nitride Normally Off MOSFET Using Dual-Metal-Gate Structure for the Improvement in Current Drivability | A gallium nitride (GaN)-based normally off metal-oxide-semiconductor field-effect transistor (MOSFET) using a dual-metal-gate (DMG) structure was proposed and fabricated to improve current drivability. Normally off operation with a high V-th of 2.3 V was obtained using a Cl-2/BCl3-based recess etching process. The DMG structure was employed to improve current characteristics, which can be degraded by recess etching. The I-D and g(m) of a DMG-based device with nickel (Ni)-aluminum (Al) were improved by 42.1% and 30.9%, respectively, in comparison to the performances of a single-metal-gate-based device with Ni because the DMG structure increased electron velocity in the channel region. This demonstrates that the DMG structure with a large work-function difference significantly improves the carrier transport efficiency. GaN-based recessed-gate MOSFETs based on the DMG structure hold promising potentials for high-efficiency power devices. | Yoon, Young Jun; Lee, Jae Sang; Kim, Dong-Seok; Lee, Jung-Hee; Kang, In Man | Korea Atom Energy Res Inst, Korea Multipurpose Accelerator Complex, Gyeongju 38180, South Korea; Kyungpook Natl Univ, Sch Elect Engn, Daegu 41566, South Korea | 57218864885; 7601467686; 55642581500; 57196140713; 7203062678 | yjyoon@kaeri.re.kr;jslee8@kaeri.re.kr;dongseokkim@kaeri.re.kr;jlee@ee.knu.ac.kr;imkang@ee.knu.ac.kr; | ELECTRONICS | ELECTRONICS-SWITZ | 2079-9292 | 9 | 9 | SCIE | COMPUTER SCIENCE, INFORMATION SYSTEMS;ENGINEERING, ELECTRICAL & ELECTRONIC;PHYSICS, APPLIED | 2020 | 2.397 | 52.9 | 0.41 | 2025-06-25 | 10 | 11 | GaN; recessed-gate; normally-off; dual-metal-gate structure | HIGH-THRESHOLD-VOLTAGE; ALGAN/GAN MIS-HEMTS; V-TH; POWER; PERFORMANCE; OPERATION; CHANNEL; HFET; SI | Dual-metal-gate structure; GaN; Normally-off; Recessed-gate | English | 2020 | 2020-09 | 10.3390/electronics9091402 | 바로가기 | 바로가기 | 바로가기 | 바로가기 | ||||
| ○ | Article | Heterogeneous cooperative bare-bones particle swarm optimization with jump for high-dimensional problems | This paper proposes a novel Bare-Bones Particle Swarm Optimization (BBPSO) algorithm for solving high-dimensional problems. BBPSO is a variant of Particle Swarm Optimization (PSO) and is based on a Gaussian distribution. The BBPSO algorithm does not consider the selection of controllable parameters for PSO and is a simple but powerful optimization method. This algorithm, however, is vulnerable to high-dimensional problems, i.e., it easily becomes stuck at local optima and is subject to the “two steps forward, one step backward” phenomenon. This study improves its performance for high-dimensional problems by combining heterogeneous cooperation based on the exchange of information between particles to overcome the “two steps forward, one step backward” phenomenon and a jumping strategy to avoid local optima. The CEC 2010 Special Session on Large-Scale Global Optimization (LSGO) identified 20 benchmark problems that provide convenience and flexibility for comparing various optimization algorithms specifically designed for LSGO. Simulations are performed using these benchmark problems to verify the performance of the proposed optimizer by comparing the results of other variants of the PSO algorithm. © 2020, MDPI AG. All rights reserved. | Lee, Joonwoo; Kim, Won | Department of Electrical Engineering, Kyungpook National University (KNU), Daegu, 41566, South Korea, Department of Robot and Smart System Engineering, Kyungpook National University (KNU), Daegu, 41566, South Korea; Department of Computer Science, Woosong University, Daejeon, 304606, South Korea | 57209469100; 56100200000 | kimwon@wsu.ac.kr; | Electronics (Switzerland) | ELECTRONICS-SWITZ | N/A | 2079-9292 | 9 | 9 | SCIE | COMPUTER SCIENCE, INFORMATION SYSTEMS;ENGINEERING, ELECTRICAL & ELECTRONIC;PHYSICS, APPLIED | 2020 | 2.397 | 52.9 | 0 | 2025-06-25 | 1 | Bare-bones PSO (BBPSO); Cooperative PSO (CPSO); High-dimensional optimization; Large-scale global optimization; Particle swarm optimization (PSO) | English | Final | 2020 | 10.3390/electronics9091539 | 바로가기 | 바로가기 | 바로가기 |
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