• Title/Summary/Keyword: interference-free

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A Method of Prediction and Analysis of Electromagnetic Interference (EMI) in Wireless Power Transfer System Operating at 13.56 MHz (13.56 MHz 무선 에너지 전송 시스템의 효율적인 전자파 장해(EMI) 예측 및 분석 방법)

  • Shim, Hyun-Jin;Park, Jong-Min;Nam, Sangwook
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.9
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    • pp.873-882
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    • 2013
  • The effective way of estimation and analysis of EMI(Electromagnetic Interference) in Wireless Power Transfer System operating at 13.56 MHz is proposed. In this paper methodology of driving magnetic field strength and electric loop current of two antennas which are in free space and on PEC plane using image theory and duality is proposed. Perfect electric conductor(PEC) is planar, infinite in extent, and perfectly conducting plane. And we will refer it as PEC plane. A equivalent circuit model is used to analyze. Using this theoretical analysis, we can derive maximum magnetic field strength of the far-field region numerically using measured data of near-field maximum magnetic field strength. The experimental results using commercial numerical simulation tool are in agreement with the theoretical results. Also, using the derivation of maximum magnetic field strength in the far-field region, we can easily estimate the maximum allowable power dissipation that meets EMI regulations.

A Multi-Channel Scheduling MAC (MCS-MAC) Protocol for Wi-Fi Mesh Networks (Wi-Fi 메쉬 네트워크를 위한 다중 채널 스케줄링 MAC (MCS-MAC) 프로토콜)

  • Wu, Ledan;Yang, Jae-Young;Zhou, Yafeng;Jeong, Han-You
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.1C
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    • pp.54-62
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    • 2012
  • A Wi-Fi mesh network providing multi-hop wireless connections based on IEEE 802.11 PHY/MAC technology has recently received a significant attention as a network infrastructure that interconnects RFID systems and wireless sensor networks (WSNs). However, the current IEEE 802.11 contention-based MAC protocol cannot fully utilize the network capacity due to eithor frame collisions or unused network resources. In this paper, we propose a novel multi-channel scheduling MAC (MCS-MAC) protocol for Wi-Fi mesh networks. Under the secondary interference model of Wi-Fi mesh networks, the MCS-MAC protocol can maximize the network throughput via activation of collision-free links that has a maximal link weight. Through the simulations, we show that the throughput of the MCS-MAC protocol is at least three times higher than that of existing MAC protocols in Wi-Fi mesh networks.

An XML-based Digital Mock-Up System for Heterogeneous Multi-CAD Assembly (XML을 이용한 이기종 CAD 조립체 DMU시스템의 설계)

  • Song, In-Ho;Chung, Sung-Chong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.31 no.6 s.261
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    • pp.635-643
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    • 2007
  • As many engineers and technicians are involved in the design process of large scale and/or complex products, there are a lot of miss matches and interferences due to designers' faults and several kinds of CAD systems. Recently, CAD systems are applied to verify and check the assembly process. Digital Mock-Up(DMU) system, a tool to build a virtual mock-up in the design stage, has been used to prevent the interferences and miss matches during precision design processes. Using the virtual assembly tool, engineers are able to design precision and interference free parts without physical mock-ups. Instead of a single CAD source, several CAD systems are used to design a complex product. Several organizations are involved in the distributed design environment for heterogeneous multi-CAD assembly. XML and the lightweight CAD file are proposed for the multi-CAD assembly. XML data contains hierarchy of the heterogenenous multi-CAD assembly. STEP PDM schema and STEP ISO 10303-28 formations are applied to construct the XML data. The lightweight CAD file produced from various CAD files through ACIS kernel and InterOp not only contains mesn, B-Rep and topological data, but also is used to visualize CAD data and to verify dimensions. Developed system is executed on the desktop computers. It does not require commercial CAD systems to visualize 3D assembly data. Real-time interference and fitness checks, dimensional verification, and design and assembly verification are performed on the developed system. Assembly of heterogeneous models for a car is conducted to verify the effectiveness of the developed DMU system on the Internet.

Implementation of WLAN Baseband Processor Based on Space-Frequency OFDM Transmit Diversity Scheme (공간-주파수 OFDM 전송 다이버시티 기법 기반 무선 LAN 기저대역 프로세서의 구현)

  • Jung Yunho;Noh Seungpyo;Yoon Hongil;Kim Jaeseok
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.42 no.5 s.335
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    • pp.55-62
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    • 2005
  • In this paper, we propose an efficient symbol detection algorithm for space-frequency OFDM (SF-OFDM) transmit diversity scheme and present the implementation results of the SF-OFDM WLAN baseband processor with the proposed algorithm. When the number of sub-carriers in SF-OFDM scheme is small, the interference between adjacent sub-carriers may be generated. The proposed algorithm eliminates this interference in a parallel manner and obtains a considerable performance improvement over the conventional detection algorithm. The bit error rate (BER) performance of the proposed detection algorithm is evaluated by the simulation. In the case of 2 transmit and 2 receive antennas, at $BER=10^{-4}$ the proposed algorithm obtains about 3 dB gain over the conventional detection algorithm. The packet error rate (PER), link throughput, and coverage performance of the SF-OFDM WLAN with the proposed detection algorithm are also estimated. For the target throughput at $80\%$ of the peak data rate, the SF-OFDM WLAN achieves the average SNR gain of about 5.95 dB and the average coverage gain of 3.98 meter. The SF-OFDM WLAN baseband processor with the proposed algorithm was designed in a hardware description language and synthesized to gate-level circuits using 0.18um 1.8V CMOS standard cell library. With the division-free architecture, the total logic gate count for the processor is 945K. The real-time operation is verified and evaluated using a FPGA test system.

Performance Assessment of High-Speed Transponder System for Rail Transport on High-Speed Line (철도교통용 고속 트랜스폰더시스템 고속선 실차 성능평가)

  • Park, Sungsoo;Lee, Jae-Ho;Kim, Seong Jin
    • Journal of the Korean Society for Railway
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    • v.19 no.3
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    • pp.304-313
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    • 2016
  • It is necessary to receive telegrams transmitted by transponder tags installed along the track in order to detect the exact position of a high-speed train. In a high-speed railway environment, telegrams can be corrupted by the electromagnetic interference that comes from onboard electric train power equipment or wayside devices. In this study, we verified the railway environment compatibility of a high-speed transponder system developed as a train position detection system. We installed transponder tags on the Honam high-speed line and measured the number of error-free telegrams received from the transponder tag while the HEMU-430X was running at 268km/h~334km/h. Based on the measurement, we estimated the length of the contact zone formed between the transponder reader and tag. Field test results allow us to estimate how many error-free telegrams can be received when HEMU-430X is at speeds up to 400km/h.

A Study on the Machining of Sculptured Surfaces by 5-Axis CNC Milling (l) Cutter Axis Direction Verctor and Post-Processing (5-축 CNC 밀링으로의 자유곡면 가공에 관한 연구 (I) 공구축 방향의 벡터와 포스트 프로세싱)

  • 조현덕;전용태;양민양
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.8
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    • pp.2001-2011
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    • 1993
  • This study deals with the machining of sculptured surfaces on 5-axis CNC milling machine with end mill cutter. The study (I) has the following contents. In 5-axis CNC milling, CL-data consist of CC-data and cutter axis direction vector at the CC-point. Thus, in machining of the sculptured surface on 5-axis CNC milling machine, determination of the direction vector of the milling cutter is very important. The direction vector is obtained by the fact that bottom plane of the milling cutter must not interfere with the free-form surface being machined. The interference is checked by the z-map method which can be applied in all geometric types of the sculptured surfaces. After generating NC part programs from 5-axis post-processing algorithms, sculptured surfaces were machined with 5-axis CNC milling machine (CINCINNATI MILACRON, 20V-80). From these machining tests, it was shown that the machining of the free-form surfaces on 5-axis CNC milling machine with the end mill has smaller cusp heights and shorter cutting time than on 3-axis CNC milling machine with the ball-end mill. Thus, 5-axis CNC end milling was effective machining method for sculptured surfaces. The study (II) deals with the prediction of cusp height and the determination of tool path interval for the 5-axis machining of sculptured surfaces on the basis of study(I).

A Report on 6 cases of Abdominal Obesity using Electroacupuncture Combined with Magnetic Acupuncture (전기와 자기장 복합 침 자극을 활용한 복부비만 치료 6례에 대한 증례 보고)

  • Yun, Gee Won;Lee, Hyun;Kim, Yun Joo;Kang, Jae Hui
    • Journal of Acupuncture Research
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    • v.32 no.4
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    • pp.213-226
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    • 2015
  • Objectives : This study was aimed to show the effect of electroacupuncture combined with magnetic acupuncture on abdominal obesity without patient dieting, exercise or use of herbal medication. Methods : Women over 85 cm in waist circumference were treated with electroacupuncture combined with magnetic acupuncture. Acupuncture points were located at the abdomen ($CV_{12}$, $CV_6$, $ST_{25}$, $ST_{21}$, $SP_{15}$, $SP_{14}$), extremities ($LI_4$, $LI_{11}$, $ST_{36}$, $ST_{44}$) and were stimulated 30 minutes with 2.1~3 Gaus, 500 Hz, tolerable strength. The Interference wave forms were by Whata 153 (Medi Lab, Korea). Two or three treatment sessions per week (five or ten sessions in total) were done. Before treatment, and after the last treatment, we measured waist circumference, hip circumference, waist hip ratio, thickness of abdominal subcutaneous fat, body weight, body mass index, body fat ratio, visceral fat area, free fat mass, body fat mass and skeletal muscle mass. We also measured the subcutaneous temperature of the abdomen($CV_{12}$, $ST_{25}(Rt)$, $ST_{25}(Lt)$, $CV_6$) by using digital infrared thermal imaging(DITI). Results : In this study, significant reductions were shown in waist circumference, hip circumference, thickness of abdominal subcutaneous fat, body weight, body mass index, body fat ratio and body fat mass. There were no significant differences in waist hip ratio, free fat mass or skeletal muscle mass. There were also significant increases of the subcutaneous temperature on $CV_{12}$, $ST_{25}(Rt)$, $ST_{25}(Lt)$. Conclusions : From the above results, electroacupuncture combined with magnetic acupuncture might be an effective treatment for abdominal obesity.

Modified Submental Intubation in Panfacial Bone Fracture Patients (전안면골 골절에서의 변형된 아래턱밑 삽관)

  • Choi, Sang-Mun;Song, Seung-Han;Kang, Nak-Heon
    • Archives of Plastic Surgery
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    • v.38 no.1
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    • pp.127-129
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    • 2011
  • Purpose: Nasotracheal or oral intubation procedure is widely used for facial bone fractures. However, during the operation intubated tube can interfere or obstruct the view of the operator. We authors used a modified submental intubation method in panfacial bone fracture patients for intact airway and the operation view. Methods: After intravenous induction of anaesthesia, traditional orotracheal tubation was done. A horizontal incision was made 2 cm from the midline, 2 cm medial to and parallel with the mandible in the submental region. 1 In order to approach to the floor of the oral cavity, a haemostat was pushed through the soft tissues. A chest tube front cover was applied to the intubation tube and the tube was inserted through the submental tunnel. Orotracheal tube was disconnected and pulled back through the soft tissue and secured with a suture. Results: The procedure took about 30 minutes and there were no problems during the intubation. Intraoral manipulation and occlusal checks were free without any interference. Extubation was also easily done without any complications such as lung aspiration, infection, hematoma, or fistula. Conclusion: Submental endotracheal intubation is fast, safe, easy to use and free from the concern about the tube being pull back again. Conventional submental intubations are being held without any coverage of the tip. We authors applied the modified method to the trauma patients and obtained satisfactory results. From the above advantages, modified submental intubation can be widely available not only in fractured patients, but also in aesthetic or orthognathic surgeries.

Permittivity Measurements of various Materials in 13-28GHz Band (13-28GHz 대역에서 다양한 매질의 유전율 측정)

  • Park, No-Uk;Jeong, Won-Ho;Jung, Myung-Won;Chong, Young-Jun;Kim, Jong-Ho;Kim, Kyung-Seok
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.14 no.1
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    • pp.161-167
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    • 2014
  • This paper presents the results of permittivities of various materials by measurements of the dielectric properties for the materials in millimeter-wave band. Since the advantages of millimeter wave band include the miniaturization, weight reduction of component and a lot of information transfer, its study has received increasing attention of researches. Also, because of the characteristics of the band have the superior straightness and the small diffractive, in the band, the analysis for the reflection and transmission characteristics of the materials will be very important. Moreover, a low interference is one of characteristics of the band due to the fact that the millimeter wave is absorbed in the materials. Therefore, in this paper, the reflection and transmission characteristics of materials are measured in the band by using the free space method. Based on the presented result, the permittivities of the materials are derived by the calculation of Nicolson-Ross Weir method.

Low Rate VLC Receiver Design Using NCP302 Voltage Detector for IoT/IoL Connected Smart Homes

  • Lee, Beomhee;Mariappan, Vinayagam;Khudaybergenov, Timur;Han, Jungdo;Cha, Jaesang
    • International journal of advanced smart convergence
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    • v.7 no.4
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    • pp.50-56
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    • 2018
  • The Internet of Things (IoT) and Visible Light Communication (VLC) is opening up new services in lighting industry by integrating sensory network features in addition to standard illumination functionality. In this progressive developments, the next generation lighting devices for smart homes are capable to sense the environmental conditions and transfer the captured data through lights to gateway controller to access remotely. The smart home environmental sensor information's are few kbps only so VLC systems need to built-in with low rate light connectivity to transfer data to the gateway. To provide error free communication, the quality of a received light signal is important to be considered when designing an VLC receiver. Therefore, this paper proposes the design of robust low rate IoL receiver design using NCP302 voltage detector for micro controller to adapt the IoT/IoL front end module for system integration. To evaluate the proposed system performance, the Arduino UNO based IoT/IoL controller designed with lighting, sensors and lights connectivity interfaces. The experimental result shows that the robust interference rejection is feasible on proposed VOL receiver and possible to have an error-free communication up to 10 kbps at a low SNR using OOK modulation.