• Title/Summary/Keyword: far field

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Internal Antenna Design for GSM900/DCS1800/PCS1900 Using an Overlap of Return Loss (반사 손실 합성법을 이용한 GSM900/DCS1800/PCS1900 내장형 안테나 설계)

  • Jang, Byung-Chan;Kim, Che-Young
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.18 no.5 s.120
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    • pp.503-510
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    • 2007
  • This paper proposes the design scheme of internal triple band antenna intended for using in GSM900, DCS1800, and PCS1900 bands. The suggested folding metal plates of the two branches are mounted on a dielectric coated ground plane for size miniaturization and durability. Return losses are overlapped when length of metal branches are controlled. This is important technique for wide band operation. For the suggested antenna geometry its return loss was calculated by HFSS 9 simulator, and was shown to be -10 [dB] less within the required band. Also, gain and radiation pattern of antenna were measured using far field measurement system in an anechoic chamber. The measured peak gain is more than 3.0 [dBi], and the average gain is over -1.0 [dBi] for the triple band, which is regarded as satisfactory for the internal antenna application. Also, the radiation pattern for two frequencies shows a similar shape each other within the required band.

Calibration of Omnidirectional Camera by Considering Inlier Distribution (인라이어 분포를 이용한 전방향 카메라의 보정)

  • Hong, Hyun-Ki;Hwang, Yong-Ho
    • Journal of Korea Game Society
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    • v.7 no.4
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    • pp.63-70
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    • 2007
  • Since the fisheye lens has a wide field of view, it can capture the scene and illumination from all directions from far less number of omnidirectional images. Due to these advantages of the omnidirectional camera, it is widely used in surveillance and reconstruction of 3D structure of the scene In this paper, we present a new self-calibration algorithm of omnidirectional camera from uncalibrated images by considering the inlier distribution. First, one parametric non-linear projection model of omnidirectional camera is estimated with the known rotation and translation parameters. After deriving projection model, we can compute an essential matrix of the camera with unknown motions, and then determine the camera information: rotation and translations. The standard deviations are used as a quantitative measure to select a proper inlier set. The experimental results showed that we can achieve a precise estimation of the omnidirectional camera model and extrinsic parameters including rotation and translation.

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Post Occupancy Evaluation of the Central Hospital in Quang Nam Province of Vietnam Funded by Korean ODA (ODA 지원 베트남 중부 꽝남성 종합병원의 거주후 평가)

  • Kwon, Soon Jung;Yu, Yeo Kyoung;Kim, Jihyun;Bang, Seol Ah
    • Journal of The Korea Institute of Healthcare Architecture
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    • v.22 no.1
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    • pp.39-49
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    • 2016
  • Purpose: This is the ex-post evaluation on "the Central General Hospital in Quang Nam Province in Vietnam" funded by Korean ODA. Through this evaluation, this study tries to explore useful ways to improve the effectiveness of Korean ODA projects related to hospital establishment. Methods: Field survey and analysis of questionaire to the staffs and patients of Quang Nam Province General Hospital were conducted twice in 2012 and 2014 after the completion of the Hospital. Two sets of surveys and questionaire outcomes have been comparatively analysed by statistics in order to seek the trend of satisfaction level of hospital users and find out the improvement way in hospital design and construction. Results: The satisfaction level on the hospital was relatively high and that of 2014 is higher than that of 2012. The satisfaction level of the users was recorded in Likert 5 scales. Continuous facility complement and maintenance is considered as the main contributor in increasing the satisfaction level of users. As far as the satisfaction level of outpatient is concerned, that of 2012 was recorded as 3.65 and that of 2014 was 4.05. In case of inpatient, the satisfaction level on the hospital in 2012 was 3.76, and 4.06 in 2014. Implications: In overseas hospital projects, proper hospital project management system including medical service plan, strategic plan, brief, design & construction and maintenance have to be put together effectively and efficiently for the success of the hospital project. At the same time local climate, culture, building material and local code have to be considered in order to build sustainable hospital.

A Study on the Significance of the Maritime Labour (2006년 해사노동협약의 채택의의)

  • Ji, Sang-Won
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.75-80
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    • 2006
  • ILO has contributed for seafarers to promote conditions of employment and decent work through maritime labour standards. Between 1920 and 1996, a total of 39 Conventions and 29 Recommendations concerning seafarers have been adopted, which demonstrates the import part of ILO activities devoted to seafarers' questions. But many instruments were outdated, deficient and not reflective of modern practice, many contained technical detail which discouraged ratification. the Governing Body of ILO, at its 262nd Session(March-April 1995), decided to set up a Working Party regarding the revision of maritime labour standards. This Working Party initiated its examination of maritime instruments to 273rd Session(November 1998) of the Governing Body. The review made by the Working Party has concluded that existing maritime Conventions were considered either up to date or were identified for promotion, most of which were approved by the Governing Body. Therefore, ILO started to create a single, coherent instrument embodying as far as possible all up-to-date standards of existing maritime labour convention. The Maritime Labour Convention 2006 has been adopted in February 2006. This paper aims to analyze the significance of this convention and the influence regarding to maritime labour affairs in the field of shipping industry.

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A Study on the Significance of the Maritime Labour Convention 2006 (2006년 해사노동협약의 채택의의)

  • Ji, Sang-Won
    • Journal of Navigation and Port Research
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    • v.31 no.1 s.117
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    • pp.115-119
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    • 2007
  • ILO has contributed for seafarers to promote conditions of employment and decent work through maritime labour standards. Between 1920 and 1996, a total of 39 Conventions and 29 Recommendations concerning seafarers have been adopted, which demonstrates the important part of ILO activities devoted to seafarers' questions. But many instruments were outdated, deficient and not reflective of modern practice, many contained technical detail which discouraged ratification. The Governing Body of ILO, at its 262nd Session(March-April 1995), decided to set up a Working Party regarding the revision of maritime labour standards. This Working Party initiated its examination of maritime instruments to 273rd Session(November 1998) of the Governing Body. The review made by the Working Party has concluded that existing maritime Conventions were considered either up to date or were identified for promotion, most of which were approved by the Governing Body. Therefore, ILO started to create a single, coherent instrument embodying as far as possible all up-to-date standards of existing maritime labour conventions. The Maritime Labour Convention 2006 was adopted in February 2006. This paper aims to analyze the significance of this Convention and the influence regarding to maritime labour affairs in the field of shipping industry.

An Investigation-Study on the Erosion at Hak-Dong Gravel Beach (학동 해빈의 침식에 관한 조사.연구)

  • 함계운;김진홍;장대정
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.14 no.1
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    • pp.65-75
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    • 2002
  • The changes of sea bottom configuration, which may cause the coastal disasters, have been considered as social problems. It is obvious that the beach deformation is attributable to the sediment transport associated with erosion and siltation in coastal areas such esturies, channel and harbors. The prediction method and countermeasures far them, however, are not on the level of satisfaction, which indicates that make efforts should be made on developing them. Groin was constructed at Hak-Dong gravel beach to embark ship at 1996, as a result region of right of groin, severe erosion of beach is proceeding till now 1999. In this study, based on the field measurements, involved the one-line theory model which was selected for the prediction of shoreline change to prepare coastal protection methods of Hak-Deng gravel beach. Author found that the storaged sediment estimation model by Sonu and Beek(1971) is useful model at the Hak-Dong gravel beach by the use of topographical survey data from September, 1998 to September, 1999.

Effect of Coverings on the Growth of Ginseng and the Persistency of Procymidone in Growing Soils (인삼재배를 위한 차광조건이 인삼의 생육과 토양 중 Procymidone의 잔류에 미치는 영향)

  • Kim, Hyo-Kun;Lee, Kyu-Seung
    • Korean Journal of Environmental Agriculture
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    • v.21 no.1
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    • pp.24-30
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    • 2002
  • Ginseng (Panax ginseng C. A. Meyer) has been cultivated on raised beds with shading condition for 4 to 6 years because of its physiological characteristics. This shading condition maintains relatively stable soil environments protecting from rainfall and direct sunlight. Therefore, pesticides in ginseng growing soil are exposed to far different environment from the general cropping field. To study the behavior of pesticides under this condition, the effect of covering on the persistency of Procymidone in ginseng cultivating soil was investigated by using several shade materials. The most important factor affecting Procymidone persistency in soil under covering was water leakage rates of shade materials.

Construction of VR Experience Pavilion Using Multi-display and ZA Sensor (멀티디스플레이와 ZA센서를 이용한 가상현실 체험관 구축 방법)

  • Joo, Jae-Hong;Lee, Hyeon-Cheol;Kim, Eun Seok
    • Proceedings of the Korea Contents Association Conference
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    • 2008.05a
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    • pp.28-32
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    • 2008
  • The displays and the interactive interfaces are important factors to enhance immersion in the VR experience pavilion. In the VR experience pavilion displaying 3D Virtual environment, it is difficult to have multi-display with single viewpoint because of the field of view. Also it costs a lot to construct a large size display. The interaction device between user and VR environment necessary to immersion has used mainly the touchscreens with the restricted display area or the button-based input devices so far. In this paper, we suggest a method for constructing extensible multi-display which are showing VR environment in realtime and a method for interaction using a ZA Sensor which is wireless and guarantees the user's unrestricted movement. The proposed method can make a VR experience pavilion more immersive at less cost.

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Ground Contact Analysis for Korea's Fictitious Lunar Orbiter Mission

  • Song, Young-Joo;Ahn, Sang-Il;Choi, Su-Jin;Sim, Eun-Sup
    • Journal of Astronomy and Space Sciences
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    • v.30 no.4
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    • pp.255-267
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    • 2013
  • In this research, the ground contact opportunity for the fictitious low lunar orbiter is analyzed to prepare for a future Korean lunar orbiter mission. The ground contact opportunity is basically derived from geometrical relations between the typical ground stations at the Earth, the relative positions of the Earth and Moon, and finally, the lunar orbiter itself. Both the cut-off angle and the orbiter's Line of Sight (LOS) conditions (weather orbiter is located at near or far side of the Moon seen from the Earth) are considered to determine the ground contact opportunities. Four KOMPSAT Ground Stations (KGSs) are assumed to be Korea's future Near Earth Networks (NENs) to support lunar missions, and world-wide separated Deep Space Networks (DSNs) are also included during the contact availability analysis. As a result, it is concluded that about 138 times of contact will be made between the orbiter and the Daejeon station during 27.3 days of prediction time span. If these contact times are converted into contact duration, the duration is found to be about 8.55 days, about 31.31% of 27.3 days. It is discovered that selected four KGSs cannot provide continuous tracking of the lunar orbiter, meaning that international collaboration is necessary to track Korea's future lunar orbiter effectively. Possible combinations of world-wide separated DSNs are also suggested to compensate for the lack of contact availability with only four KGSs, as with primary and backup station concepts. The provided algorithm can be easily modified to support any type of orbit around the Moon, and therefore, the presented results could aid further progress in the design field of Korea's lunar orbiter missions.

Study on an Evaluation of Remote Control Torch Performance to reduce CO2 Welding Defects (CO2 용접결함 감소를 위한 원격 제어 토치 성능 평가 연구)

  • Kim, Jeong-Hyeok;Oh, Seck-Hyeog;Lee, Hae-Gil
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.10
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    • pp.6282-6288
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    • 2014
  • $CO_2$ welding is used widely in the field. On the other hand, welding defects occur when welders cannot adjust the current and voltage needed for welding and have to stop working to adjust the current and voltage, causing sudden cooling down of the welding structure inside a vehicle or tank where the control panel is invisible or when work site is far. This study used three types of existing $CO_2$ welders. This also applied SS400 rolled steel for welding structural purposes for remote control torch welding, perform a welding test through v-groove butt welding with a remote control torch and existing $CO_2$ welding torch, conducted visual inspection on the appearance of a welded top bead. In addition, the appearance quality of the welding part was monitored mainly through penetrant testing and a bending test to evaluate the welding defect reduction and the effect on the performance and compatibility by replacing the existing welder.