• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.11a
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• pp.226-229
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• 2003

본 논문은 Wireless LAN 주파수 대역$(5725\~5825\;MHz)$에서의 다차원패턴기술(Photonic Band Gap : PBG)을 이용한 Yagi-Uda 안테나와 결합하여 광대역 마이크로스트립 패치 안테나를 구현 하였으며, PBG Cell을 이용한 안테나와 이용하지 않은 안테나를 비교 분석하였다. PBG 구조를 적용한 안테나에서의 대역폭이 약 30 MHz 정도 더 넓게 나왔으며, 안테나의 이득은 -1dB정도 더 낮게 나왔는데 이는 Ground 면에 2차원적인 PBG Cell을 적용한 효과 때문으로 분석된다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06b
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• pp.77-81
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• 1996

In order to conform to the needs of effective program production in multimedia era, we are studying Desk Top Program Production system. With the DTPP, users can easily produce multimedia program including video, sound, and ancillary data, and freely handle video images synthesizing video components retrieved from video database. This paper describes the new program production system, DTPP and its key technologies such as cooperative program production via multimedia network, indexing and utilization of attribute information of images, and image segmentation and spatio-temporal editing.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06b
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• pp.88-93
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• 1996

We developed a visualization system for sports broadcasting that informs TV viewers of a sports player's sequential performing forms and locus in detail when gymnastic game such as‘vault’is broadcasted. It records the corresponding frames while a player is performing, extracts only the player's performing forms from background scenes by a proposed algorithm, superposes them sequentially on a background scene, and broadcasts them with slow speed. This system named as‘Multi-Motion’has ever been used in NHK live broadcasting for 1995 World Gymnastics Championships held in Japan.

• Journal of Engineering Education Research
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• v.17 no.4
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• pp.54-57
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• 2014

This paper investigated the influence of foreign words, otherwise known as loan words, on global communication abilities of university students from two non English-speaking countries: Korea and Japan. To survey the understanding and usage of foreign words which are from English language and used frequently in daily conversation, questionnaires were administered to Korean and Japanese university students majoring in engineering who shared similar linguistic backgrounds. The results were analyzed from global communication viewpoint. Based on the results, methods for improving global communication skills in engineering education were proposed.

• Journal of Multimedia Information System
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• v.7 no.2
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• pp.189-196
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• 2020

We have developed a device for recording biological data by inserting three electrodes and a needle with an angular velocity sensor into the moth for the purpose of measuring the electromyogram of the flapping and the corresponding lift force. With this measurement, it is possible to evaluate the moth-physiological function of moths, and the amount of pesticides that insects are exposed to (currently LD50-based standards), especially the amount of chronic low-concentration exposure, can be reduced the dose. We measured and recorded 2-channel electromyography (EMG) and angular velocity corresponding to pitch angle (pitch-like angle) associated with wing flapping for 100 sweet potato hawkmoths (50 females and 50 males) with the animals suspended and constrained in air. Overall, the angular velocity and amplitude of EMG signals demonstrated high correlation, with a correlation coefficient of R = 0.792. In contrast, the results of analysis performed on the peak-to-peak (PP) EMG intervals, which correspond to the RR intervals of ECG signals, indicated a correlation between ΔF fluctuation and angular velocity of R = 0.379. Thus, the accuracy of the regression curve was relatively poor. Using a DC amplification circuit without capacitive coupling as the EMG amplification circuit, we confirmed that the baseline changes at the gear change point of wing flapping. The following formula gives the lift provided by the wing: angular velocity × thoracic weight - air resistance - (eddy resistance due to turbulence). In future studies, we plan to attach a micro radio transmitter to the moths to gather data on potential energy, kinetic energy, and displacement during free flight for analysis. Such physiological functional evaluations of moths may alleviate damage to insect health due to repeated exposure to multiple agrochemicals and may lead to significant changes in the toxicity standards, which are currently based on LD50 values.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.5
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• pp.705-712
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• 2001

In this paper, a new type of aperture coupled microstrip patch antenna with tilted-beam based on the principal of the dipole yagi antenna is proposed and investigated experimentally. Its configuration is composed by 3 types of patches; reflector, driver, and director. Tilted beam patterns are effected by many parameters as those of dipole yagi antenna; sizes of the patches, gaps between the patches, characteristics of the substrates, feeding method and etc. Therefore, in this paper, the effects of varying design parameters of this antenna are studied with a goal of enhancing the gain and tilting the beams. A microtrip patch antenna with tilted beam based on performance trade-offs is designed and fabricated. Measured and simulated results for return loss and radiation patterns are presented. It has 45$^{\circ}$ tilted beam and very close to simulation beam pattern at resonant frequency, 2.58 GHz.

• Journal of Advanced Navigation Technology
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• v.8 no.2
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• pp.98-104
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• 2004

When a straight-in landing from an instrument approach using ILS or VOR/DME is not possible or desirable because of topographical reason or bad weather, a circling approach maneuver is initiated by the pilot to align the aircraft with a runway for landing. Visual contact with the runway is necessary while conducting a circle to land maneuver. This research is to develop a new warning system based on a convention marker system which alerts pilots to watch out for exceeding the circling approach area. The airborne system also uses the same receiver unit without any new installations. The objective of this research is to design and develop a Yagi antenna in a special form. The research includes computer simulations to determine the size of antenna radiation pattern and to compute an expected flight path in case of alarm to validate effectiveness of the system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.10
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• pp.1269-1274
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• 2019

The paper presents a design of simple four-element microstrip-patch array antenna that is suitable for 5G applications. The proposed array consists of four rectangular microstrip patch elements with semicircular etches made on both sides of each elements. The antenna is fed using the combination of series and corporate feeding networks. The size of the ground is also changed to improve the antenna frequency. Finally, yagi elements are also added to improve the directive gain of the antenna. The presented microstrip patch array is able to achieve wide frequency bandwidth of 21.95-31.86 GHz. The antenna has also attained gain of 9.7 dB at 28 GHz and has maintained high gain and high directivity throughout the frequency band. The proposed array antenna fed by series-corporate feeding network, with low profile and simple structure is a good candidate for 5G applications.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.4
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• pp.41-48
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• 2022

This study is a study that designed in-building antennas with improved orientation to improve 5G quality in buildings as 5G is stabilized and more and more traffic is expected to occur in buildings. Instead of applying the forward arrangement of antenna elements, which is the Yagi antenna propagation orientation principle, the antenna design method of vertical arrangement applied to the base station antenna was proposed, and it was confirmed through experiments that antenna orientation increased. According to the experimental results, the directivity did not increase significantly within 10m of the separation distance from the antenna, but the directivity increased by about 3dB at the distance separated by more than 10m. Considering that the wireless environment in the building has various variables such as structure of internal structure, materials such as concrete and glass, closed space, and walls, it is expected that antenna with improved orientation can expand the scope of 5G quality improvement and maintain stable communication service in the building.

• Applied Biological Chemistry
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• v.2
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• pp.29-35
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• 1961

The daily variation in the total quantity of flavin compounds (FAD, FMN, FR) in greenbean during its germination were measured by Yagi's methods. The results obtained were as follow. 1. The total quantity of flavin compounds of the greenbean sprouts was increased with growth of sprouts until the 8th days. After this period its contents were decreased slightly. 2. The flavin compounds of greenbean sprouts were comfirmed to be synthesized as free riboflavin during its germination. 3. FAD was the major pat of total flavin compounds in cotyledon but there was significant variation in the contents of FAD, FMN and FR in hypocotyl.