• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.5
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• pp.1040-1046
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• 2015

With the rapid progress of electronics and radio communication technology, human enjoys greater freedom in information communication. However, EMW (Electro-Magnetic Wave) environments have become more complicate and difficult to control. Thus, international organizations, such as the American National Standard Institution (ANSI), Federal Communications Commission (FCC), the Comite Internationale Special des Perturbations Radio Electrique (CISPR), etc, have provided standard for controlling the EM wave environments and for the countermeasure of the electromagnetic compatibility (EMC). In this paper, the status of EMW absorbers and the goal of smart EMW absorber in the future were described. Furthermore, design method of the smart EM wave absorber with heat radiating function was suggested. The designed smart EM wave absorber has the absorption ability of more than 20 dB from 2 GHz to 2.45 GHz band, the optimum aperture (hole) size, the adjacent hole space, and the thickness of which were 6 mm, 9 mm, and 6.5 mm, respectively. Thus, it is respected that these results can be applied as various EMC devices in electronic, communication, and controlling systems.

• Journal of Biosystems Engineering
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• v.39 no.1
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• pp.21-33
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• 2014

Background: Significant technological development and changes happened in the tractor industries. Contrariwise, the test procedures of the major standard development organizations (SDO's) remained unchanged or with a little modification over the years, demanding new tractor test standards or improvement of existing ones for tractor performance, safety, and comfort. Purpose: This study focuses on reviewing the research trends regarding performance, safety and comfort evaluation of agricultural tractors. Based on this review, few recommendations were proposed to revise or improve the current test standards. Review: Tractor power take-off power test using the DC electric dynamometer reduced human error in the testing process and increased the accuracy of the test results. GPS signals were used to determine acceleration and converted into torque. High capacity double extended octagonal ring dynamometer has been designed to measure drawbar forces. Numerical optimization methodology has been used to design three-point hitch. Numerous technologies, driving strategies, and transmission characteristics are being considered for reducing emissions of gaseous and particulate pollutants. Engine emission control technology standards need to be revised to meet the exhaust regulations for agricultural tractors. Finite Element Analysis (FEA) program has been used to design Roll-Over Protective Structures (ROPS). Program and methodology has been presented for testing tractor brake systems. Whole-body vibration emission levels have been found to be very dependent upon the nature of field operation performed, and the test track techniques required development/adaptation to improve their suitability during standardized assessment. Emphasizes should be given to improve visibility and thermal environment inside the cab for tractor operator. Tractors need to be evaluated under electromagnetic compatibility test conditions due to large growing of electronic devices. Research trends reviewed in this paper can be considered for possible revision or improvement of tractor performance, safety, and comfort test standards.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.2
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• pp.77-86
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• 2005

The DC protection and control device for the feeding system of a Light Rail Transit(LRT) system is developed. For the development, the short circuit characteristics in the system are analyzed. As a result a protection algorithm for the DC fault selective relay (50F) is newly proposed, and principles of the DC fault selective relay, Line Test Device (LTD), DC Over Current Relay (DC OCR) are introduced From the development, the specifications and codes used to be unclear have become clarified and summarized. Moreover, the methods to examine the protective characteristics and Electromagnetic Compatibility (EMC) are established Finally, the performance and the effectiveness of the developed protective relay have been verified with the test based on IEC. For the reliability of the system, the relay has been installed and is being operated at the test track of the LRT system at Gyeong-San.

• Journal of Navigation and Port Research
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• v.28 no.8
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• pp.715-719
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• 2004

This paper deals with EMC filter for a personal computer(PC). A PC contains many sources of noise inside and out, with many connected cables. High noise levels are also emitted from the PC because of high-speed signals. So radiated noise from the computer body may sometimes cause problems. Therefore, we design and fabricate an electromagnetic compatibility (EMC) filter for PC, which is composed of feed-through capacitors and ferrite beads with high permeability. Through extensive test, the proposed EMC filter is shown to have excellent differential-mode and common-mode noises filtering characteristics above 30 dB in the frequency band from 10 MHz to 1.5 GHz. The immunity characteristics are improved more than 10 to 30 dB over the frequency band from DC to 1.8 GHz.

• Journal of Aerospace System Engineering
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• v.17 no.4
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• pp.110-117
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• 2023

In this paper, the optimal placement of the rotary wing's communication and navigation antennas was evaluated by measuring their performance through ground simulations and flight tests. To select the mounting position of the communication and navigation antenna on the helicopter, after considering the shape and characteristics of the airframe, the radiation patterns, coupling analysis, equipment operation profiles, and antenna type analysis were performed for the aircraft-mounted antenna. Based on the analysis results, a procedure for sequentially performing voltage standing wave ratio (VSWR) measurement and antenna pattern test was established through ground and flight tests of the antenna. The systematic performance measurement method and procedure proposed in this paper were verified through ground and flight tests of the Light Armed Helicopter (LAH) system.

• Journal of Advanced Navigation Technology
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• v.27 no.5
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• pp.587-593
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• 2023

In this paper, we propose a systematic design approach based on cavity-mode resonance analysis to improve the radiated susceptibility of cables in air vehicles. As electronic devices equipped in air vehicles substantially increase, enhancing the radiated susceptibility of internal cables becomes more challenging and significant. The proposed design approach provides an efficient method to avoid and suppress cavity-mode resonances using analytical methods to estimate the resonance frequencies and the current ratio induced by the cavity-mode resonances. It is demonstrated in simulated results that the proposed method offers a design solution for improving the radiated susceptibility and reduces the computation time by up to 99.6% compared to the previous design method.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.8
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• pp.76-82
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• 2016

In this paper, we evaluated shielding effectiveness (SE) of carbon nanotube (CNT) film using near field scanning (NFS) in near field analysis. We adopted CNT film with deposit carbon density of 5% and thickness of 1mm for evaluation of shielding characteristic. Using a test coupon analogized to an actual IC package, we measured SE according to measuring position and SE according to distances between the CNT film and the test coupon. As a result, the measured SE in the near field varied with frequency. Especially, the measured electric field SE in the center of the test coupon is better than that of the measured edge point of the test coupon where it is affected by fringing effect. The results show that the measured SE in the near field is affected not only by frequency but also by measurement environment such as position and height of the probe and height of shielding film. In conclusion, we should choose proper methods for SE measurement considering interference distance in the electronic control system because there is little correlation between the proposed evaluation method in the near field and ASTM D 4935-10.

• Journal of IKEEE
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• v.24 no.1
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• pp.302-310
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• 2020

In this paper, we have implemented the living waste analysis system based on IoT and AI(Artificial Intelligence), and proposed effective waste process and management method. The Jeju location have the strong point to devise a stratagem and estimate waste quantization, rather than others. Especially, we can recognized the amount variation of waste to the residence people compare to the sightseer number, and the good example a specific waste duty. Thus this paper have developed the IoT device for interconnecting the existed CCTV camera, and use the AI algorithm to analysis the waste image. By using these decision of image analysis, we can inform their deal commend and a decided information to the map of the waste cars. In order to evaluate the performance of IoT, we have experimented the electromagnetic compatibility under a national official authorization KN-32, KN61000-4-2~6, and obtained the stable experimental results. In the further experimental results, we can applicable for an data structure for precise definition command by using the simulated several waste image with artificial intelligence algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.2
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• pp.250-256
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• 2006

The revision of radio waves act, which took effect on July 1,2005, widened the bandwidth of PLC from $9kHz{\sim}450kHz$ to $9kHz{\sim}30MHz$. This high upper limit of frequency may cause the interference in HF wireless communications. From this point of view, the goal of this research is to suggest the estimation method of whether-or-not the interference occurs and furthermore offer countermeasures to avoid it hereafter. Ministry of Information and Communication Radio Research Laboratory(MIC-RRL)has been researching for the interference and devoting themselves to turn out how much it affects to HF wireless communications since the revision took effect. This research suggests some estimation methods with receivers, signal generators, or SINAD(Signal to Noise and Distortion) Meter which is so suitable for the RF environment that we can overcome the existing limit to the EMC environment. In addition, this research is focused on securing the environment for wireless communications by establishing the safety zone or suggesting the ways to prohibit the use of the bandwidth, which may cause serious interference, in order to minimize the effect of PLC on HF maritime mobile telecommunications.