• Title/Summary/Keyword: Ins Choi

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An Integrated Navigation System Combining INS and Ultrasonic-Speedometer to Overcome GPS-denied Area (GPS 음영 지역 극복을 위한 INS/초음파 속도계 결합 항법 시스템 설계)

  • Choi, Bu-Sung;Yoo, Won-Jae;Kim, La-Woo;Lee, Yu-Dam;Lee, Hyung-Keun
    • Journal of Advanced Navigation Technology
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    • v.23 no.3
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    • pp.228-236
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    • 2019
  • Recently, multi-sensor integration techniques have been actively studied to obtain reliable and accurate navigation solution in GPS (Global Positioning System)-denied harsh environments such as urban canyons, tunnels, and underground roads. In this paper, we propose a low-cost ultrasonic-speedometer utilizing the characteristics of the ultrasonic propagation. An efficient integrated INS (inertial navigation system)/ultrasonic-speedometer navigation system is also proposed to improve the accuracy of positioning in GPS-denied environments. To evaluate the proposed system, car experiments with field-collected measurements were performed. By the experiment results, it was confirmed that the proposed INS/ultrasonic-speedometer system bounds the positioning error growth effectively even though GPS signal is blocked more than 10 seconds and a low-cost MEMS IMU (micro electro mechanical systems inertial measurement unit) is utilized.

Gravity Modeling and Validation for High Accuracy Navigation Computation

  • Cho, Yun-Cheol;Shin, Yong-Jin;Park, Jeong-Hwa;Kim, Cheon-Joong;Choi, Kyung-Ryong
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.64.1-64
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    • 2001
  • Errors in inertial navigation system(INS) can be divided into two major groups which are system related errors and modeling errors due to approximation and linearization. Measurement noise, calibration, and alignment errors make up the first group, whereas the uncertainties in the gravity vector fall in the second category and are important error source for high quality INS, especially during high altitude and and/or long time missions, when the gravity errors tent to build up. The quality of a medium to high accuracy INS depends on the knowledge of the local gravity field. In this paper, the feasibility of improving airborns INS by use of more accurate gravity model is studied. To make consistent comparisons, WGS-84 parameters are used and ...

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Caffeine and 2-Aminoethoxydiphenyl Borate (2-APB) Have Different Ability to Inhibit Intracellular Calcium Mobilization in Pancreatic Acinar Cell

  • Choi, Kyung-Jin;Kim, Kab-Sung;Kim, Se-Hoon;Kim, Dong-Kwan;Park, Hyung-Seo
    • The Korean Journal of Physiology and Pharmacology
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    • v.14 no.2
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    • pp.105-111
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    • 2010
  • Inositol 1,4,5-trisphosphate receptors ($InsP_3Rs$) modulate $Ca^{2+}$ release from intracellular $Ca^{2+}$ store and are extensively expressed in the membrane of endoplasmic/sarcoplasmic reticulum and Golgi. Although caffeine and 2-aminoethoxydiphenyl borate (2-APB) have been widely used to block $InsP_3Rs$, the use of these is limited due to their multiple actions. In the present study, we examined and compared the ability of caffeine and 2-APB as a blocker of $Ca^{2+}$ release from intracellular $Ca^{2+}$ stores and $Ca^{2+}$ entry through store-operated $Ca^{2+}$ (SOC) channel in the mouse pancreatic acinar cell. Caffeine did not block the $Ca^{2+}$ entry, but significantly inhibited carbamylcholine (CCh)-induced $Ca^{2+}$ release. In contrast, 2-APB did not block CCh-induced $Ca^{2+}$ release, but remarkably blocked SOC-mediated $Ca^{2+}$ entry at lower concentrations. In permeabilized acinar cell, caffeine had an inhibitory effect on InsP3-induced $Ca^{2+}$ release, but 2-APB at lower concentration, which effectively blocked $Ca^{2+}$ entry, had no inhibitory action. At higher concentrations, 2-APB has multiple paradoxical effects including inhibition of Ins$P_3$-induced $Ca^{2+}$ release and direct stimulation of $Ca^{2+}$ release. Based on the results, we concluded that caffeine is useful as an inhibitor of $InsP_3R$, and 2-APB at lower concentration is considered a blocker of $Ca^{2+}$ entry through SOC channels in the pancreatic acinar cell.

Mobile Mapping System Development Based on MEMS-INS for Measurement of Road Facility (도로시설물 계측을 위한 MEMS-INS 기반 모바일매핑시스템(MMS) 개발)

  • Lee, Kye Dong;Jung, Sung Heuk;Lee, Ki Hyung;Choi, Yun Soo;Kim, Man Sik
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.36 no.2
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    • pp.75-84
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    • 2018
  • The purpose of this study is that the low-cost mobile mapping system using INS (Inertial Navigation System) based on MEMS (Micro Electro Mechanical System) could decipher the interpretation of road facility with the accuracy of x, y 0.546m plane error. Even though the MMS (Mobile Mapping System) technology as a new measurement technology has been used vividly to set up geographic information by some world leading surveying equipment manufacturers, the domestic technology is still in its beginning stage. Several domestic institutes and companies tried to catch up the leading technology but they just produced prototypes which needs more stabilization. Through this thesis, we developed low-cost mobile mapping system installed with INS based on MEMS after time synchronizing sensors for MMS such as LiDAR (Light Detection And Ranging), CCD (Charge Coupled Device), GPS/INS (Global Positioning System / Inertial Navigation System) and DMI (Distance Measurement Instrument).

Research on Process Technology of Molded Bridge Die on Substrate (MBoS) for Advanced Package (Advanced Package용 Molded Bridge Die on Substrate(MBoS) 공정 기술 연구)

  • Jaeyoung Jeon;Donggyu Kim;Wonseok Choi;Yonggyu Jang;Sanggyu Jang;Yong-Nam Koh
    • Journal of the Microelectronics and Packaging Society
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    • v.31 no.2
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    • pp.16-22
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    • 2024
  • With advances of artificial intelligence (AI) technology, the demand is increasing for high-end semiconductors in various places such as data centers. In order to improve the performance of semiconductors, reducing the pitch of patterns and increasing density of I/Os are required. For this issue, 2.5dimension(D) packaging is gaining attention as a promising solution. The core technologies used in 2.5D packaging include microbump, interposer, and bridge die. These technologies enable the implementation of a larger number of I/Os than conventional methods, enabling a large amount of information to be transmitted and received simultaneously. This paper proposes the Molded Bridge die on Substrate (MBoS) process technology, which combines molding and Redistribution Layer (RDL) processes. The proposed MBoS technology is expected to contribute to the popularization of next-generation packaging technology due to its easy adaption and wide application areas.

A Study on Measuring the Misaligned Angle between Seeker and Inertial Navigation System (탐색기와 관성항법장치 간 비정렬각 측정 기법 연구)

  • Kim, Taehoon;Lee, Hojun;Jeong, Jinseob;Choi, Hongseok
    • Journal of the Korea Institute of Military Science and Technology
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    • v.17 no.1
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    • pp.135-141
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    • 2014
  • In order to guide a flying object which uses a seeker(SKR) and an inertial navigation system(INS) properly, we should confirm that axes of both equipments are aligned in the scope expected. In this paper we have proposed a method to measure the misaligned angle between a SKR and an INS during the system integration procedure. And we expanded this method to measure misalignments between several SKRs and an INS in case of captive flight test.

Tightly-Coupled GPS/INS/Ultrasonic-Speedometer/Barometer Integrated Positioning for GPS-Denied Environments

  • Choi, Bu-Sung;Yoo, Won-Jae;Kim, Lawoo;Lee, Yu-Dam;Lee, Hyung-Keun
    • Journal of Positioning, Navigation, and Timing
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    • v.9 no.4
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    • pp.387-395
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    • 2020
  • Accuracy of an integrated Global Positioning System (GPS) / Inertial Navigation System (INS) relies heavily on the visibility of GPS satellites. Especially, its accuracy is dramatically degraded in urban canyon due to signal obstructions due to large structures. In this paper, we propose a new integrated positioning system that effectively combines INS, GPS, ultrasonic sensor, and barometer in GPS-denied environments. In the proposed system, the ultrasonic sensor provides velocity information along the forward direction of moving vehicle. The barometer output provides height information compensated for the pressure variation due to fast vehicle movements. To evaluate the performance of the proposed system, an experiment was carried out by mounting the proposed system on a test car. By the experiment result, it was confirmed that the proposed system bears good potential to maintain positioning accuracy in harsh urban environments.

Localization of the surface vehicles using DWT and GPS/INS fusion algorithm (DWT와 GPS/INS융합 알고리즘을 이용한 수면이동체의 위치 인식)

  • Yoo, Han-Dong;Lee, In-Uk;Choi, Won-Suck;Lee, Jang-Myung
    • The Journal of Korea Robotics Society
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    • v.10 no.1
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    • pp.1-8
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    • 2015
  • This paper proposes a study for accurate surface localization system using DWT(Discrete Wavelet Transform) and GPS/INS fusion algorithm. Because the propagation in the underwater is not passed by characteristics of the medium unlike the ground, the sonar system like DVL is used instead of GPS. But since these systems are installed on the seafloor and operated, a long time is required for installation and navigation systems are limited outside of the range area. And it is difficult to estimate position in a three-dimensional considering the depth in actual marine environment. In this paper, before the development of underwater localization system, precisely estimated position system is proposed in a two-dimensional by developing surface localization system using removing noise and disturbance with DWT and relatively inexpensive GPS and INS sensor.

Tightly Coupled INS/GPS Navigation System using the Multi-Filter Fusion Technique

  • Cho, Seong-Yun;Kim, Byung-Doo;Cho, Young-Su;Choi, Wan-Sik
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.349-354
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    • 2006
  • For robust INS/GPS navigation system, an efficient multi-filter fusion technique is proposed. In the filtering for nonlinear systems, the representative filter - EKF, and the alternative filters - RHKF filter, SPKF, etc. have individual advantages and weak points. The key concept of the multi-filter fusion is the mergence of the strong points of the filters. This paper fuses the IIR type filter - EKF and the FIR type filter - RHKF filter using the adaptive strategy. The result of the fusion has several advantages over the EKF, and the RHKF filter. The advantages include the robustness to the system uncertainty, temporary unknown bias, and so on. The multi-filter fusion technique is applied to the tightly coupled INS/GPS navigation system and the performance is verified by simulation.

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Screening of Plant Resources of anti-viral activity (항바이러스 활성 식물자원 탐색)

  • Kwon, Dur-Han;Kim, Man-Bae;Yoon, Do-Young;Lee, Young-Hee;Kim, Jae-Wha;Lee, Hee-Gu;Choi, In-Seong;Lim, Jong-Seok;Choe, Yong-Kyeung
    • Korean Journal of Medicinal Crop Science
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    • v.11 no.1
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    • pp.24-30
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    • 2003
  • Aqueous extracts from eleven species of Korean medicinal plants were screened for antiviral activity against transmissble gastroenteritis virus (TGEV) and porcine epidemic diarrhae virus (PEDV). Seven of eleven plant extracts were found to have cytotoxicity for ST cells at the concentration of 1mg/ml, and ten extracts except Ephedra sinica were found to have non-cytotoxicity for Vero cells at the same concentration, Extracts of Zanthoxylum piperium, Cudrina tricuspidata, Clerodendron trichomum, Sophora flavescens, effectively inhibited TGEV, respectively. There were the antiviral activity against TGEV in the extracts of Glesdistsia sinensis, Euonymus alatus, Ficus carica, Solanum nigrum, Ephedra sinica, Xanthium strumarium, Acanthopanax seeliflorus in spite of their cytotoxicities. Nine extracts except Xanthium strumarium and Acanthopanax seeliflorus were found to have the antiviral activitity against PEDV. Extracts of Zanthoxylum piperium, Sophora flavescens was shown to have antiviral activities against both TGEV and PEDV.