• 제어로봇시스템학회논문지
• /
• 제14권12호
• /
• pp.1294-1301
• /
• 2008

Under passive RFID environment, this paper presents a new localization of a mobile robot traversing over the floor covered with tags, which is superior to existing methods in terms of estimation performance and cost effectiveness. Basically, it is assumed that a mobile robot is traveling along a series of straight line segments, each segment at a certain constant velocity, and that the number of tags sensed by a mobile robot at each sampling instant is at most one. First, for a given line segment with known starting point, the velocity and position of a mobile robot is estimated using the spatial and temporal information acquired from the traversed tag. Some discussions are made on the validity of the basic assumptions and the localization for the initial segment with unknown starting point. Second, for a given tag distribution density, the optimal tag arrangement is considered to reduce the position estimation error as well as to make easy the tag attachment on the floor. After reviewing typical tag arrangements, the pseudorandom tag arrangement is devised inspired from the Sudoku puzzle, a number placement puzzle. Third, through experiments using our passive RFID localization system, the validity and performance of the mobile robot localization proposed in this paper is demonstrated.

• Journal of Chest Surgery
• /
• 제54권6호
• /
• pp.494-499
• /
• 2021

Background: A recent increase in the incidental detection of ground glass nodules (GGNs) has created a need for improved diagnostic accuracy in screening for malignancies. However, surgical diagnosis remains challenging, especially via video-assisted thoracoscopic surgery (VATS). Herein, we present the efficacy of a novel electrical navigation system for perioperative percutaneous transthoracic nodule localization. Methods: Eighteen patients with GGNs who underwent electromagnetic navigated percutaneous transthoracic needle localization (ETTNL), followed by 1-stage diagnostic wedge resections via VATS between January and December 2020, were included in the analysis. Data on patient characteristics, nodules, procedures, and pathological diagnoses were collected and retrospectively reviewed. Results: Of the 18 nodules, 17 were successfully localized. Nine nodules were pure GGNs, and the remaining 9 were part-solid GGNs. The median nodule size was 9.0 mm (range, 4.0-20.0 mm); and the median depth from the visceral pleura was 5.2 mm (range, 0.0-14.4 mm). The median procedure time was 10 minutes (range, 7-20 minutes). The final pathologic results showed benign lesions in 3 cases and malignant lesions in 15 cases. Conclusion: Perioperative ETTNL appears to be an effective method for the localization of GGNs, providing guidance for a 1-stage VATS procedure.

• 대한조선학회논문집
• /
• 제58권6호
• /
• pp.424-430
• /
• 2021

Fire localization is a key mission that must be preceded for an autonomous fire suppression system. Although studies using a variety of sensors for the localization are actively being conducted, the fire localization is still unfinished due to the high cost and low performance. This paper presents the modeling and simulation of the fire localization estimation using Bayesian estimation to determine the probabilistic location of the fire. To minimize the risk of fire accidents as well as the time and cost of preparing and executing live fire tests, a 40m × 40m-virtual space is created, where two ultraviolet sensors are simulated to rotate horizontally to collect ultraviolet signals. In addition, Bayesian estimation is executed to compute the probability of the fire location by considering both sensor errors and uncertainty under fire environments. For the validation of the proposed method, sixteen fires were simulated in different locations and evaluated by calculating the difference in distance between simulated and estimated fire locations. As a result, the proposed method demonstrates reliable outputs, showing that the error distribution tendency widens as the radial distance between the sensor and the fire increases.

• 한국지능시스템학회논문지
• /
• 제18권5호
• /
• pp.706-711
• /
• 2008

본 논문에서는 Inertial Navigation System (INS)와 Ultrasonic-SATellite (U-SAT)의 센서융합을 기반으로 100mm 이하의 정밀위치측정 시스템을 보여준다. INS는 자이로와 두 개의 엔코더로 구성되고, U-SAT는 네 개의 송신기와 한 개의 수신기로 구성하였다. 구성된 센서들은 정밀한 정밀위치측정을 위하여 Extended Kalman Filler (EKF)를 통해 센서들을 융합하였다. 위치측정의 성능을 증명하기 위해 본 논문에서는 로봇이 0.5 m/s의 속도로 주행한 실제 데이터(직진, 곡선)와 시뮬레이션을 통한 실험을 하였으며, 실험에 사용된 위치측정방법은 일반적인 센서융합과 INS 데이터만을 칼만 필터에 이용한 센서융합을 비교하였다. 시뮬레이션과 실제 데이터를 통해 실험한 결과, INS 데이터만을 칼만 필터에 이용한 센서융합이 더 정밀함을 확인할 수 있었다.

• Journal of Positioning, Navigation, and Timing
• /
• 제6권4호
• /
• pp.159-166
• /
• 2017

The position of autonomous driving vehicle is basically acquired through the global positioning system (GPS). However, GPS signals cannot be received in tunnels. Due to this limitation, localization of autonomous driving vehicles can be made through sensors mounted on them. In particular, a 3D Light Detection and Ranging (LIDAR) system is used for longitudinal position error correction. Few feature points and structures that can be used for localization of vehicles are available in tunnels. Since lanes in the road are normally marked by solid line, it cannot be used to recognize a longitudinal position. In addition, only a small number of structures that are separated from the tunnel walls such as sign boards or jet fans are available. Thus, it is necessary to extract usable information from tunnels to recognize a longitudinal position. In this paper, fire hydrants and evacuation guide lights attached at both sides of tunnel walls were used to recognize a longitudinal position. These structures have highly distinctive reflectivity from the surrounding walls, which can be distinguished using LIDAR reflectivity data. Furthermore, reflectivity information of tunnel walls was fused with the road surface reflectivity map to generate a synthetic reflectivity map. When the synthetic reflectivity map was used, localization of vehicles was able through correlation matching with the local maps generated from the current LIDAR data. The experiments were conducted at an expressway including Maseong Tunnel (approximately 1.5 km long). The experiment results showed that the root mean square (RMS) position errors in lateral and longitudinal directions were 0.19 m and 0.35 m, respectively, exhibiting precise localization accuracy.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2005년도 ICCAS
• /
• pp.1775-1780
• /
• 2005

One of the most important factors so that mobile objects can achieve their purpose is the information about their positions. In this paper, we propose an improved beacon system, to which ultrasonic sensors are attached, for the indoor localization of mobile objects. We have researched so that it can cover the wider space and estimate more accurate positions than the existent beacon systems. The existent beacon systems have the constraint that one beacon cannot cover wide area since ultrasonic sensors have limits in the angle of signal (beam-angle) on which their signal strength depends. Hence, we used the active beacon which consists of a pan-tilt mechanism and a beacon module. The active beacon system can always aim at mobile objects in order to transmit the strongest signal of the ultrasonic sensors into the objects using the pan-tilt mechanism. In addition, this system is inexpensive because it can decrease the number of beacons by about a half of the beacons of the existent system. Finally, the results show what is the difference between the active beacon system and existent beacon systems, and how accurate it is.

• 제어로봇시스템학회논문지
• /
• 제21권5호
• /
• pp.490-495
• /
• 2015

As flying robots are becoming popular, there are increased needs to use themforsuch purposes as parcel delivery, serving in restaurants, and stage performances. To control flying robots such as quad copters, localization is essential. In order to properly position flying robots, many techniques are in development, including IR (infra-red)-based systemswhich catch markers on a flying robot in order that it can position itself. However, this technique demonstrates only short coverage. Furthermore, localization from inertial sensors diverges as time passes. For this reason, this paper suggests a TWR (two-way ranging) based positioning technique. Despite the weaknesses in currently available TWR system, this paper suggests a self-positioning and outlier detection technique in order to provide reliable position information with a faster update rate. The self-positioning system sends a shorter message which reduces wireless traffic. By detecting and removing outlier measurements, a positioning result with better accuracy is acquired. Finally, this paper shows that the suggesting system detects outlierssequentially from less than half the number of anchors in localization system according to the degree of outlier in measurement and the noise level. By performing an outlier algorithm, better positioning accuracy is acquired as shown in the experimental result.

• International journal of advanced smart convergence
• /
• 제5권4호
• /
• pp.21-25
• /
• 2016

Recent development in multi-channel surround is emerging in various formats to provide better stereoscopic and sound effects to consumers in recent broadcasting. The ability sound localize the sound sources in space is most considerable design factor on multi-channel surround system for human earing perception model. However, this paper propose the change of the sound localization according to the spacing of the speakers, which is not covered in the existing research focus on sound system design. Presently the sound system uses the position and number of the speakers to localize the sound. In the multi-channel surround environment, the proposed design uses the sound localization is caused by the directional characteristics of the speaker, the distance between the speakers and the distance between the listener and the speaker according to the directivity is required. The proposed design is simulated using virtual measurement with MATLAB simulation environment and performances are measured.

• 통상정보연구
• /
• 제16권4호
• /
• pp.409-437
• /
• 2014

본 논문은 기업의 현지화의 중요성을 주목하여 현지화의 이론적 배경 및 전략적 모형을 도출하고, 모형의 틀 안에서 인도에 진출한 한국 개별기업의 현지화 성공과 실패사례를 비교분석함으로써 성공적인 현지화에 대한 시사점을 제시하고자 하였다. 현지화의 전략적 모형을 생산 및 소싱의 현지화, 인적자원의 현지화, 마케팅의 현지화, R&D의 현지화와 관련한 경영관리 측면과 현지사회와의 융화, 본사의 현지 자회사 권한위양으로 나누었다. 인도에 진출한 한국기업의 성공과 실패사례를 분석한 결과, 생산 및 소싱의 현지화 부분에서는, 현지에서 부품을 조달하고 현지 소비자가 선호하는 모델을 생산하여 성공적으로 정착한 기업과 소비자가 선호하지 않는 모델을 생산하여 실패한 기업도 있었다. 인적자원의 현지화 부분에서는, 성공한 대부분의 기업들이 현지 인력의 중요성을 인지하여 교육을 통하여 인적자원을 적극적으로 활용한 것으로 나타났다. 마케팅의 현지화 부분에서는, 효과적인 마케팅과 AS망을 구축한 기업, 철저한 사전 시장조사와 관리가 가능하고 기술력 있는 현지 파트너를 선정한 기업, 영업활동 및 고객지원, 불만처리를 직접 수행한 기업은 현지화에 성공하였다. R&D의 현지화 부분에서는, 성공한 대기업은 현지 고객에 맞는 제품을 개발하기 위해 현지에서 연구 개발 센터를 운영하고 있는 것으로 나타났다. 현지사회와의 융화 부분에 있어서는, 문화적 환경을 이해하지 못하면 실패하였지만 적극적인 사회공헌활동을 전개하고 지역사회에 봉사하는 기업은 성공적인 현지화가 이루어진다는 것을 보여준다. 본사의 현지 자회사 권한위양 부분에서는, 대부분 기업이 이 부분이 취약했고 본사에 의해 의사결정이 이루어지는 경향이 있었다. 현지화 전략의 시사점은 부품의 현지화, 기업의 경영이념과 시스템을 이해하고 시장 전략 결정에 자율적으로 참여하는 고급 간부직책 인재의 육성, 단독투자 추진, R&D센터의 설치 및 운영, 문화와 제도에 대한 이해 및 기업의 사회적 책임 강화, 현지 경영진의 자율권 부여 등이다.

• 정보교육학회논문지
• /
• 제12권1호
• /
• pp.49-56
• /
• 2008

초등학교 사회과 교육의 가장 큰 특징은 전 과정에서의 지역화라고 설명할 수 있다. 그 중 3학년 사회과의 내용은 지역의 성격과 생활 경험을 강조하고 있으며 제7차 교육과정 사회과에서는 최근 컴퓨터 통신과 인터넷의 발달로 새로운 형태의 지역화 자료의 유형과 활용 방안이 중요시되고 있다. 본 연구에서 개발한 웹 기반 지역화 학습 시스템은 이러한 정보화 시대의 요구에 부응하여 초등학교 3학년 사회과 교육과정을 중심으로 경기도 평택 지역의 내용을 학습할 수 있도록 하였다. 또한 현재 학교 현장에서 주된 학습 자료로 쓰이고 있는 초등학교 3학년 지역화 보조 교과서 외에 학생들이 자기 주도적으로 웹에서 활용할 수 있는 학습 시스템을 제작함으로써 부족한 지역 자료를 제공하고자 한다.