• Title/Summary/Keyword: Directional Information

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Wireless LAN-based Vehicle Location Estimation in GPS Shading Environment (GPS 음영 환경에서 무선랜 기반 차량 위치 추정 연구)

  • Lee, Donghun;Min, Kyungin;Kim, Jungha
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.19 no.1
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    • pp.94-106
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    • 2020
  • Recently, the radio navigation method utilizing the GPS(Global Positioning System) satellite information is widely used as the method to measure the position of objects. As GPS applications become wider and fields based on various positioning information emerge, new methods for achieving higher accuracy are required. In the case of autonomous vehicles, the INS(Inertial Navigation System) using the IMU(Inertial Measurement Unit), and the DR(Dead Reckoning) algorithm using the in-vehicle sensor, are used for the purpose of preventing degradation of accuracy of the GPS and to measure the position in the shadow area. However, these positioning methods have many elements of problems due not only to the existence of various shaded areas such as building areas that are continually enlarged, tunnels, underground parking lots and but also to the limitations of accumulation-based location estimation methods that increase in error over time. In this paper, an efficient positioning method in a large underground parking space using Fingerprint method is proposed by placing the AP(Access Points) and directional antennas in the form of four anchors using WLAN, a popular means of wireless communication, for positioning the vehicle in the GPS shadow area. The proposed method is proved to be able to produce unchanged positioning results even in an environment where parked vehicles are moved as time passes.

Implementation of ATM/Internet Gateway System for Real Time Multimedia Service (실시간 멀티미디어 서비스를 위한 ATM/Internet 게이트웨이 시스템의 구현)

  • Han Tae-Man;Jeong You-Hyeon;Kim Dong-Won
    • The KIPS Transactions:PartC
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    • v.11C no.6 s.95
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    • pp.799-806
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    • 2004
  • A growing diversity of pervasive devices is gaming access to the Internet and other information. However, much of the rich multimedia contents cannot be easily handled by the client devices because of the limited communication, processing, storage and display capabilities. The in-tegration of voice, data and video service modified the target of networking technologies. Networks must have some the capabilities for in-tegration of various services and also for QoS support as required by each of those service. Because of these reasons, we developed EAGIS(Efficient ATM Gateway for real time Internet Service) to provide seamless multimedia service between the ATM network and the Internet. EAGIS consists of the interworking unit, content server, transcoding server, and the serveice broker to provide seamless multimedia service be-tween the ATM network and the Internet. In this paper, we design the architecture and transcoding service scenario of the EAGIS. When the RTP is used for the bi-directional communication, transcoding time is configured by the time-stamp of RTCP. When HTTP is used for unidirec-tional communication, self-timer is used. By using these reference time, standard transcoding method is applicable according to the frame trans-mission rate and network traffic load. And we can also assure the QoS of the multiple users` effective bandwidth by our algorithm.

Design and Fabrication of Modified Monopole Antenna for Wireless USB Dongle with WLAN system Applications (WLAN 시스템 적용 가능한 무선 USB 동글용 변형된 모노폴 안테나의 설계 및 제작)

  • Lee, Yeong-Seong;Mun, Seung-Min;Kim, Gi-Rae;Yoon, Joong-Han
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.10
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    • pp.2223-2231
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    • 2015
  • In this paper, we propose a built-in antenna for wireless USB dongle which has a modified structure from the existing planar monopole antenna. The proposed antenna implemented a dual-band characteristic by inserting Strip1, Strip2, Strip3 into the monopole structure combined with 'n' shape and feeded 50-Ω using coaxial cable. The antenna is designed on an FR-4 substrate of which the dielectric constant is 4.6, and its overall size is 10 mm × 50 mm × 1mm. Based on the measurement results of the return loss, it was confirmed to satisfy the dual band resonance characteristics of 740 MHz (2.3 ~ 2.7 GHz) and 1,200 MHz (5.15 ~ 5.825 GHz) by -10 dB. In addition, we obtain the omni-directional radiation pattern measurements in the operating frequency bands, and the maximum gain of the proposed antenna has 2.26~3.81 dBi in the 2.4 GHz band and 2.21~5.79 dBi. in the 5.5 GHz band, respectively.

A Study on the Characteristics of Monolithic Laser-Waveguide Coupler by BPM (BPM에 의한 Monolithic Laser-Waveguide Coupler의 특성 연구)

  • 장지호;최태일;최병하
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.1
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    • pp.100-110
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    • 1994
  • In this paper, we present a new analysis of monolithic laser-waveguide coupling structure employing the beam propagation method. Monolithic laser-waveguide coupler has both passive and active components It has too many parameters to consider for an analysis. So we present proper model of coupler by use of directional coupler. We employ the beam propagation method th analyze the proposed structure, we could employ the coupled mode theory but we thought in the case of this paper the beam propagation method is more appropriate than coupler mode theorybecause a number of variables which to consider is too many for the coupled mode theory. Also we use finite difference method to calcurate trial field which is a starting point of beam propagation analysis. Through this approach, we can consider more parameters. And we propose a new structure of monolothic laser-waveguide coupler which has taper structure between the distance in which coupling is taking place and passive waveguide. We can obtain 79% high coupling efficiency from our structure.

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Application of Geomorphological Features for Establishing the Preliminary Landslide Hazard (초기 산사태 위험도 구축을 위한 지형요소의 활용)

  • Cha, A Reum;Kim, Tai Hoon;Gang, Seok Koo
    • Journal of Korean Society for Geospatial Information Science
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    • v.23 no.3
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    • pp.23-29
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    • 2015
  • Due to the characteristics of landslide disasters including debris flow, the rapid speed to downward and difficulty to respond or evacuate from them, it is imperative to identify their potential hazards and prepare the reduction plans. However, the current landslide hazards generated by a variety of methods has been raised its accuracy because of the complexity of input data and their analyses, and the simplification of the landslide model. The main objective of this study is, therefore, to evaluate the preliminary landslide hazard based on the identification of geomorphological features. Especially, two methodologies based on the statistics of the directional data, Vector dispersion and Planarity analyses, are used to find some relationships between geomorphological characteristics and the landslide hazard. Results show that both methods well discriminate geomorphological features between stable and unstable domains in the landslide areas. Geomorphological features are closely related to the landslide hazard and it is imperative to maximize their characteristics by adapting multiple models rather than individual model only. In conclusions, the mechanism of landslide is not determined solely by a simple cause but the complex natural phenomenon caused by the interactions of the numerous factors and it is of primary importance to require additional researches for the outbreaking mechanism that are based on various methodologies.

Analysis of Optimum Antenna Placement Considering Interference Between Airborne Antennas Mounted on UAV (무인항공기 탑재 안테나 간 간섭을 고려한 안테나 최적 위치 분석)

  • Choi, Jaewon;Kim, Jihoon
    • Journal of the Institute of Electronics and Information Engineers
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    • v.52 no.6
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    • pp.32-40
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    • 2015
  • In this paper, the optimum antenna placement is analyzed by considering the interference between airborne antennas mounted on the unmanned aerial vehicle(UAV). The analysis is implemented by selecting the antennas that the distance and operational frequency band between airborne antennas is close to each other among the omni-directional antennas. The analyzed antennas are the control datalink, TCAS(Traffic Collision & Avoidance System), IFF(Identification Friend or Foe), GPS(Global Positioning System), and RALT(Radar ALTimeter) antennas. There are three steps for the optimum antenna placement analysis. The first step is selecting the antenna position having the optimum properties by monitoring the variation of radiation pattern and return loss by the fuselage of UAV after selecting the initial antenna position considering the antenna use, type, and radiation pattern. The second one is analyzing the interference strength between airborne antennas considering the coupling between airborne antennas, spurious of transmitting antenna, and minimum receiving level of receiving antenna. In case of generating the interference, the antenna position without interference is selected by analyzing the minimum separation distance without interference. The last one is confirming the measure to reject the frequency interference by the frequency separation analysis between airborne antennas in case that the intereference is not rejected by the additional distance separation between airborne antennas. This analysis procedure can be efficiently used to select the optimum antenna placement without interference by predicting the interference between airborne antennas in the development stage.

The study on lead-lag relationship between VKOSPI and KOSPI200 (VKOSPI와 KOSPI200현선물간의 선도 지연 관계에 관한 연구)

  • Lee, Sang-Goo;Ohk, Ki-Yoo
    • Management & Information Systems Review
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    • v.31 no.4
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    • pp.287-307
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    • 2012
  • We empirically examine the price discovery dynamics among the VKOSPI, the KOSPI200 spot, and the KOSPI200 futures markets. The analysis employs the vector-autoregression, Granger causality, impulse response function, and variance decomposition using both daily data from 2009. 04. 13 to 2011. 12. 30 and 1 minute data from the bull market, bear market, and the flat period. The main results are as follows; First, the lead lag relationships between KOSPI200 spot(futures) yield VKOSPI returns could not be found from the daily data analysis. But KOSPI200 spot(futures) have a predictive power for VKOSPI from 1 minute data. Especially KOSPI200 spot(futures) and VKOSPI show the bi-directional effects to each other during the return rising period Second, We chose the VAR(1) the model in daily data but adopt the VAR(3) model in the one minute data to determine the lead lag time. We know that there is predictability during the very short period Third, Spot returns and futures returns makes no difference in daily data results. According to the one minite data results, VKOSPI returns have a predictive power for KOSPI200 spot return, but have no predictive power for KOSPI200 futures return.

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An Omnidirectional High Gain Antenna for UHF Band Ground Station (UHF대역 지상국용 무지향 고이득 안테나)

  • Bae, Ki-Hyoung;Chang, Min-Soo;Joo, Jae-Woo;Hwang, Chan-Ho;Hong, Ki-Pyo
    • Journal of the Korea Knowledge Information Technology Society
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    • v.12 no.4
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    • pp.539-550
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    • 2017
  • In this paper, we designed, fabricated and tested an UHF band cylindrical dipole array antenna. In the proposed antenna, cylindrical dipoles were vertically arranged in four stages. A parallel structure feeding circuit was installed inside the cylindrical dipole and mounted so as to be broadband matching. The feeding circuit was installed at the center of the cylindrical dipole to optimize the gain flatness characteristic of the azimuth direction omnidirectional radiation pattern. Minimizing the difference between the signals branched from the feeding circuit and realizing the symmetry of the radiation pattern. The required specifications are more than 11.2% bandwidth in UHF band, above 6dBi antenna gain, standing wave ratio of 2:1 or less, less than ±1dB±1dB gain flatness in azimuth radiation pattern, more than 13 degrees in elevation radiation pattern of 3dB beamwidth. We confirmed the possibility of implementation through M&S and verified the result of M&S through production and testing. The test results are 11.2% bandwidth in the UHF band, 6.30 to 8.31 dBi gain, 1.53:1 standing wave ratio or less, within ±0.2dB±0.2dB gain flatness in the azimuth radiation pattern, elevation radiation pattern of 3dB beam width was 15.62 to 15.84 degrees. The test result meets all requirements specifications.

Recognition of dog's front face using deep learning and machine learning (딥러닝 및 기계학습 활용 반려견 얼굴 정면판별 방법)

  • Kim, Jong-Bok;Jang, Dong-Hwa;Yang, Kayoung;Kwon, Kyeong-Seok;Kim, Jung-Kon;Lee, Joon-Whoan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.12
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    • pp.1-9
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    • 2020
  • As pet dogs rapidly increase in number, abandoned and lost dogs are also increasing in number. In Korea, animal registration has been in force since 2014, but the registration rate is not high owing to safety and effectiveness issues. Biometrics is attracting attention as an alternative. In order to increase the recognition rate from biometrics, it is necessary to collect biometric images in the same form as much as possible-from the face. This paper proposes a method to determine whether a dog is facing front or not in a real-time video. The proposed method detects the dog's eyes and nose using deep learning, and extracts five types of directional face information through the relative size and position of the detected face. Then, a machine learning classifier determines whether the dog is facing front or not. We used 2,000 dog images for learning, verification, and testing. YOLOv3 and YOLOv4 were used to detect the eyes and nose, and Multi-layer Perceptron (MLP), Random Forest (RF), and the Support Vector Machine (SVM) were used as classifiers. When YOLOv4 and the RF classifier were used with all five types of the proposed face orientation information, the face recognition rate was best, at 95.25%, and we found that real-time processing is possible.

Multi-Objective Onboard Measurement from the Viewpoint of Safety and Efficiency (안전성 및 효율성 관점에서의 다목적 실선 실험)

  • Sang-Won Lee;Kenji Sasa;Ik-Soon Cho
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2023.11a
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    • pp.116-118
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    • 2023
  • In recent years, the need for economical and sustainable ship routing has emerged due to the enforced regulations on environmental issues. Despite the development of weather forecasting technology, maritime accidents by rough waves have continued to occur due to incorrect weather forecasts. In this study, onboard measurements are conducted to observe the acutal situation on merchant ships in operation encountering rough waves. The types of measured data include information related to navigation (Ship's position, speed, bearing, rudder angle) and engine (engine revolutions, power, shaft thrust, fuel consumption), weather conditions (wind, waves), and ship motions (roll, pitch, and yaw). These ship experiments was conducted to 28,000 DWT bulk carrier, 63,000 DWT bulk carrier, 20,000 TEU container ship, and 12,000 TEU container ship. The actual ship experiment of each ship is intended to acquire various types of data and utilize them for multi-objective studies related to ship operation. Additionally, in order to confirm the sea conditions, the directional wave spectrum was reproduced using a wave simulation model. Through data collection from ship experiments and wave simulations, various studies could be proceeding such as the measurement for accurate wave information by marine radar and analysis for cargo collapse accidents. In addition, it is expected to be utilized in various themes from the perspective of safety and efficiency in ship operation.

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