• 패션비즈니스
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• 제9권5호
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• pp.96-113
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• 2005

The purpose of this study was to examine acutely effective marketing strategies for bridge line imported handbag brands in order to succeed in launch and establishment in local market. Based on the successful bridge line imported handbag brands status in local market, this selected the brands, "LeSprotsac", "Longchamp", "Sequoia" that execute brand strategy including positioning strategies such as basic concept, prices, materials, promotion, distributions in order to succeed in local launching. For corroborate analysis, three staffs in each brands, consecutive in-person interviews and continuous telephone interviews, mail survey were used for this study. The results were as follows; First, differentiate brand positioning strategy that has considered accurate analysis of niche market and domestic market environment when brand launch effects on brand value enhancement. Second, marketing mix activity based on positioning strategy effects on establishing brand image and spreading brand awareness. Third, marketing activity based on positioning strategy should be executed based on consistent brand strategy.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1015-1017
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• 2003

Recently, DGPS or RTK-GPS techniques enable us to use satellite based positioning systems with high accuracy. But in urban area, navigation systems suffer from problems such as signal blockage by high-rise buildings, multi-path problems, and so on. So we have to know numbers of visible satellites and quality of signals received at the ground level in urban area as accurate as possible. In this paper, we developed a simulation system called LoQAS [Location service Quality Assessment System, 2002, the University of Tokyo] which can simulate numbers of visible satellites and DOP values using accurate satellite orbital data and 3-D digital map. In this time, we evaluated this system and extended it to deal with reflected signals to assess multi-path problems.

• Journal of Positioning, Navigation, and Timing
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• 제9권4호
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• pp.379-385
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• 2020

The satellite employs an adaptive beamformer to efficiently detect various signals and to suppress multiple interference signals, simultaneously. Although the adaptive beamforming satellite system needs Angle-of-Arrival (AOA) information of the desired signal, it is difficult to estimate the signal AOAs on the satellite environment. However, the AOA estimation on the ground control tower is more efficient and accurate comparing to the satellite environment. In this paper, we propose an adaptive beamforming satellite system based on the signal location information on the ground, consisting on an angle estimator, an adaptive beamformer, and signal processing & D/B unit. The ground control tower estimates the accurate location of the signal source, and it sends the estimated coordinates of the desired signal to the satellite. The angle estimator mounted on the satellite calculates the desired signal AOA, based on the signal location information transmitted from the ground control center. The satellite beamformer detects the desired signal and suppresses unwanted signals based on the signal AOA calculated by the angle estimator. We provide computer simulation results to present the performance of the proposed satellite adaptive beamforming system based on the signal location information.

• Journal of Platform Technology
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• 제11권5호
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• pp.97-103
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• 2023

전 세계에서 보편 일률적으로 사용되는 실외 측위 기술인 GPS와 달리, 실내 측위 기술분야는 아직 다양한 기술이 난립하고 있다. 정확한 실내 위치 정보를 획득하기 위해 대표적인 실내 측위 기술의 표준이 필요한 실정이다. 최근 실내 측위 기술이 고정밀 위치 데이터를 기반으로 한 RTLS(Real Time Location Service) 영역으로 확대되고 있다. 이에 따라 새로운 방식의 실내 측위 기술들이 제안되고 있는데, 인공지능의 발전에 힘입어 스마트폰의 무선 신호 데이터를 사용하는 인공지능 기반의 실내 측위 기술이 빠르게 발전하고 있다. 이때 인공지능 학습에 필요한 데이터를 수집하는 과정에서, 왜곡되거나 학습에 부적합한 데이터가 포함되어 실내 측위 정확도가 낮아지는 결과가 발생하기도 한다. 본 연구에서는 수집된 데이터의 정제 과정을 통해 향상된 실내 위치 확인 결과를 얻기 위한 인공지능학습용 데이터 전처리 기술을 제안한다.

• 한국통신학회논문지
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• 제34권12A호
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• pp.982-990
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• 2009

IEEE 802.15.4 무선 센서 네트워크는 물리적 또는 환경적 조건을 모니터링하고 수집 하기 위해 센서를 사용하는 독자적인 디바이스로 구성된 무선 네트워크 이다. 최근 센서기술과 정보통신 인프라의 발전으로 환경 모니터링 기술의 하나인 위치추적 기술에 대한 관심이 증가되고 있다. 센서네트워크에서의 일반적인 수신신호 세기 RSSI(Received Signal Strength Indication)를 활용한 위치인식 시스템은 장애물이나 RF의 전파지연 및 멀티패스에 의해 정확한 위치 추적이 어렵다. 따라서 본 논문에서는 RSSI 기반의 위치 추적 시스템이 가지고 있는 이러한 문제를 해결하기 위해 Gaussian Filter algorithm을 적용하여 위치 인식 성능을 개선한다. 이에 RSSI 값에 따른 전파 감쇠 특성을 논의한 후, 노드마다 개별 RSSI 값에 따른 확률적 거리 테이블을 작성한 후 생성된 모델을 통해, 센서 노드로부터 추출된 데이터를 본 논문에서 제안한 Gaussian Filter Algorithm을 적용하여 오차개선을 하였다.

• Ocean and Polar Research
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• 제27권3호
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• pp.335-339
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• 2005

The underwater positioning system is important in interpreting data that are acquired from towing vehicles such as the deep-sea camera (DSC) system. Currently, several acoustic positioning systems such as long baseline (LBL), short baseline (SBL), and ultra short baseline (USBL), are used for underwater positioning. The accurate position of DSC, however, could not be determined in a R/V Onnuri unequipped with any of these underwater positioning systems. As an alternative, the DSC position was estimated based on the topography of towing track and cable length in the cruises before 1999. The great uncertainties, however, were found in the areas of flat bottom topography. In the 2003 and 2004 cruises these uncertainties were reduced by calculating the position of DSC with the cable length and seafloor depth below the vessel. The Japanese cruises for Mn-nodule used a similar estimation method for the DSC positioning system with a CTD sensor. Although the latter can provide better information for the position of DSC, the USBL underwater positioning system is strongly recommended for establishing better positioning of DSC and other towing devices.

• 한국정보통신학회논문지
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• 제11권1호
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• pp.198-205
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• 2007

유비쿼터스 환경에 있는 사용자는 현재 자신의 위치, 시간 그리고 주변의 상태에 기반한 상황 인식 서비스를 받을 수 있다. 이러한 상황 인식 컴퓨팅에서 위치 기반서비스는 매우 중요한 역할을 한다. 위치를 측정하기 위하여 전용 장비를 설치하고 운영하는 데 많은 비용이 소요되기 때문에 기존의 WLAN(Wirless Local Area Netowork) 인프라스트럭처가 구축된 환경에서 무선 장비만을 이용하여 위치를 측정하는 방법들이 연구되고 있다. 이미 위치가 알려지고 고정된 AP(Access Point)와 노드간의 RSSI(Received Signal Strength Indicator)만을 이용하는 비콘 기반의 위치 측정 시스템 보다 무선 장비들 간의 RSSI 까지도 이용하는 상호 협력 위치 측정 시스템(Cooperative Positioning System)은 정확성이 높기 때문에 많은 관심을 끌고 있다. 본 논문에서는 상호 협력 위치 측정 시스템 중의 하나인 기존의 WiPS(wireless LAM based indoor Positioning System)의 문제점을 분석하고, 이웃하는 노드간의 영향 관계를 밝히고, 노드의 밀도에 따라 위치 수렴 조정 계수를 결정하여 성능을 개선한 WiCOPS-d(Wireless Cooperative Positioning System using node density)를 제안한다.

• Journal of Positioning, Navigation, and Timing
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• 제7권4호
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• pp.217-226
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• 2018

According to the Korea Coast Guard's maritime disaster statistics (Korea Coast Guard 2017, Korean Statistical information Service 2018), an average of 2,140 marine accidents occurred every year for the past 6 years and the number of accidents is increasing every year. Among them, maritime accidents of fishing vessels are the most frequent, and recently accidents involving fishing boat and leisure vessels are rapidly increasing as well. In particular, the number of accidents involving leisure vessels increased to about one-third of the accidents of fishing vessels, and emergency rescue requests are increasing every year accordingly. However, the number of crash accidents involving users of small vessels and marine leisure activities are increasing because of the difficulties of installing navigation equipment and electronic navigation charts. Recently, the demand for precise positioning using mobile devices is increasing in the fields of maritime safety, piloting support, and coastal survey. Although various applications of smart devices provide location-based services for users, the measurement results are discontinuous when using the position coordinates of the National Marine Electronics Association (NMEA) calculated by smartphone. Recently, Google announced that they will provide GPS raw data to developers from Android 7.0 Nougat. As a result, developers have an opportunity to receive precise carrier phase and code measurements to make more accurate positioning according to the performance of Android devices. This study analyzed GPS positioning performance using Android devices, and compared and analyzed the positioning performance at sea with high-performance GPS receivers.

• 로봇학회논문지
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• 제8권1호
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• pp.29-36
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• 2013

This paper presents a sensitivity optimization of a MEMS (microelectromechanical systems) gyroscope for a magnet-gyro system. The magnet-gyro system, which is a guidance system for a AGV (automatic or automated guided vehicle), uses a magnet positioning system and a yaw gyroscope. The magnet positioning system measures magnetism of a cylindrical magnet embedded on the floor, and AGV is guided by the motion direction angle calculated with the measured magnetism. If the magnet positioning system does not measure the magnetism, the AGV is guided by using angular velocity measured with the gyroscope. The gyroscope used for the magnet-gyro system is usually MEMS type. Because the MEMS gyroscope is made from the process technology in semiconductor device fabrication, it has small size, low-power and low price. However, the MEMS gyroscope has drift phenomenon caused by noise and calculation error. Precision ADC (analog to digital converter) and accurate sensitivity are needed to minimize the drift phenomenon. Therefore, this paper proposes the method of the sensitivity optimization of the MEMS gyroscope using DEAS (dynamic encoding algorithm for searches). For experiment, we used the AGV mounted with a laser navigation system which is able to measure accurate position of the AGV and compared result by the sensitivity value calculated by the proposed method with result by the sensitivity in specification of the MEMS gyroscope. In experimental results, we verified that the sensitivity value through the proposed method can calculate more accurate motion direction angle of the AGV.

• Journal of Positioning, Navigation, and Timing
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• 제1권1호
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• pp.7-14
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• 2012

Due to inaccurate safe navigation estimates, maritime accidents have been occurring consistently. In order to solve this, the precise positioning technology using carrier phase information is used, but due to high buildings near inland waterways or inclination, satellite signals might become weak or blocked for some time. Under this weak signal environment for some time, the GPS raw measurements become less accurate so that it is difficult to search and maintain the integer ambiguity of carrier phase. In this paper, a method to generate code and carrier phase measurements under this environment and maintain resilient navigation is proposed. In the weak signal environment, the position of the receiver is estimated using an inertial sensor, and with this information, the distance between the satellite and the receiver is calculated to generate code measurements using IGS product and model. And, the carrier phase measurements are generated based on the statistics for generating fractional phase. In order to verify the performance of the proposed method, the proposed method was compared for a fixed blocked time. It was confirmed that in case of a weak or blocked satellite signals for 1 to 5 minutes, the proposed method showed more improved results than the inertial navigation only, maintaining stable positioning accuracy within 1 m.