• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.333-335
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• 2006

Position of surface objects can be fixed in many ways. The most popular radionavigational systems, including satellite systems, make possible obtaining nearly continuous and very precise ship's position. However, under the water application of radionavigational systems is impossible. Underwater navigation requires other tools and solutions then these encountered in surface and air navigation. In underwater environment vehicles and submarines, operate that have to possess alternative navigational systems. Underwater vehicles, in order to perform their tasks require accurate information about their own, current position. At present, they are equipped with inertial navigational systems (INS). Accuracy of INS is very high but in relatively short periods. Position error is directly proportional to time of working of the system. The basic feature of INS is its autonomy and passivity. This characteristic mainly decides that INS is broadly used on submarines and other underwater vehicles. However, due to previously mentioned shortcoming i.e. gradually increasing position error, periodical calibration of the system is necessary. The simplest calibration method is surface or nearly surface application of GPS system. Another solution, which does not require interruption of performed task and emergence on the surface, is application of comparative navigation technique. Information about surrounding environment of the ship, obtained e.g. by means sonic depth finder or board sonar, and comparing it with accessible pattern can be used in order to fix ship's position. The article presents a structure and a description of working of underwater vehicle navigation system simulator. The simulator works on the basis of comparative navigation methods which exploit in turn digital images of echograms and sonograms. The additional option of the simulator is ability to robust estimation of measurements. One can do it in order to increase accuracy of position fixed with comparative navigation methods application. The simulator can be a basis to build future underwater navigation system.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2011년도 춘계학술대회
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• pp.20-21
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• 2011

본 연구는 선원 신체검사제도 개선을 위한 기초 자료를 제공하기 위한 목적으로 우리나라에서 시행중인 신체검사 항목들과 선진해운국에서 시행중인 신체검사 항목들을 비교 분석하였으며, 또한, 선원신체검사 판정기준에 대한 객관성 강화를 위해 육상의 철도 운송 종사자와 해운선진국의 신체검사 판정기준을 비교분석하였다. 이를 바탕으로 현행 신체검사 항목에 대한 유지, 수정, 새로운 항목의 추가와 판정기준에 대해 의학 전문가의 자문을 통해 객관적 기준을 제안함으로써 선원 신체검사 제도의 개선을 위한 기초정보자료를 제시하였다.

• ETRI Journal
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• 제38권6호
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• pp.1104-1113
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• 2016

Non-linear document navigation refers to the process of repeatedly reading a document at different levels to provide an overview, including selective reading to search for useful information within a document under time constraints. Currently, this function is not supported well by small-screen tablets. In this study, we propose the concept of structure-aware touch-based scrolling (SATS), which allows structural document navigation using region-dependent touch gestures for non-sequential navigation within tablets or tablet-sized e-book readers. In SATS, the screen is divided into four vertical sections representing the different structural levels of a document, where dragging into the different sections allows navigating from the macro to micro levels. The implementation of a prototype is presented, as well as details of a comparative evaluation using typical non-sequential navigation tasks performed under time constraints. The results showed that SATS obtained better performance, higher user satisfaction, and a lower usability workload compared with a conventional structural overview interface.

• 한국CDE학회논문집
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• 제19권3호
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• pp.272-280
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• 2014

Most of the car navigation systems pzrovide 2D or 3D virtual map-based driving guidance. One of the important issues is how to reduce cognitive burden to the driver who should interpret the abstracted information to real world driving information. Recently, an augmented reality (AR)-based navigation is considered as a new way to reduce cognitive workload by superimposing guidance information into the real world scene captured by the camera. In particular, head-up display (HUD) is popular to implement AR navigation. However, HUD is too expensive to be set up in most cars so that the HUD-based AR navigation is currently unrealistic for navigational assistance. Meanwhile, smartphones with advanced computing capability and various sensors are popularized and also provide navigational assistance. This paper presents a research on cognitive effect and responsiveness of an AR navigation by a comparative study with a conventional virtual map-based navigation on the same smartphone. This paper experimented both quantitative and qualitative studies to compare cognitive workload and responsiveness, respectively. The number of eye gazing at the navigation system is used to measure the cognitive effect. In addition, questionnaires are used for qualitative analysis of the responsiveness.

• 대한인간공학회지
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• 제32권5호
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• pp.443-448
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• 2013

Objective: Purposes of this study are selecting main factors in evaluating the usability of mobile navigation and comprehending mutual importance among the factors. Background: Mobile navigation services have been more diffused than ever as the number of smartphone users sharply increased. However users are having trouble with the usage of mobile navigation services due to the lack of research in the area. Method: In order to attain results, general research on mobile navigation, 1st general survey, and 2nd comparative survey on navigation UI experts were performed. Empirical studies about the results were performed using AHP method. Results: As the result of AHP analysis, accuracy was drawn out to be the most important factor followed by accessibility and visibility. Regarding the characteristics of navigation system, the provision of accurate POI(Point of Interest) was considered to be the most important factor for the experts. And effectiveness was considered to be the most important, followed by satisfaction and efficiency. Conclusion: When evaluating the usability of mobile navigation, prior factors such as accuracy, visibility, and aesthetics should be considered in advance and general evaluation concentrated on effectiveness must be performed. Application: The results of this study are expected to be a fundamental data to mobile navigation design.

• Journal of Positioning, Navigation, and Timing
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• 제13권1호
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• pp.35-44
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• 2024

This investigation primarily focuses on the generational characteristics of satellites utilized in the existing Global Navigation Satellite System (GNSS) and Regional Navigation Satellite System (RNSS), with a central emphasis on comparing the operational status of the latest generation satellites. Variations among satellite generations in physical attributes, energy consumption, and timekeeping are observed, enabling an exploration of the developmental trends over successive generations. Through a comparative analysis of the latest generation satellites, particularly in terms of performance, this study aims to furnish essential insights into the satellites employed within each system. Consequently, it will contribute to a foundational understanding of the past, present, and future GNSS satellites.

• 정보관리연구
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• 제38권3호
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• pp.59-80
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• 2007

본 연구에서는 국내 11개 국외 5개의 법학도서관 웹사이트 내비게이션 시스템을 전역, 지역, 문맥, 지원 내비게이션으로 나누어 분석하였다. 그 결과 전역 내비게이션은 일관된 내비게이션을 제공해야 하며, 핵심지역과 기능에 바로 접근할 수 있어야 하는 것으로 나타났다. 지역 내비게이션의 Quick Link는 스크롤바의 이동이 가능하도록 제공할 필요가 있었다. 문맥 내비게이션의 메뉴의 수와 링크 유형은 가급적 적은 수를 제공해야 하는 것으로 나타났다. 마지막으로 지원 내비게이션의 사이트맵과 사이트색인은 웹사이트의 콘텐트의 양에 따라 알맞게 제공해야 하며, 누락된 링크가 없어야 하며 제공내용이 충실해야 하는 것으로 나타났다.

• 항공우주기술
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• 제10권2호
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• pp.1-10
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• 2011

본 논문은 스마트무인기 위성관성항법장치(DGNS)의 신뢰성 검증을 위해 다른 위성관성 항법장치(Athena511, Nav420)와의 비행시험 결과를 비교하여 기술한다. DGNS의 성능 및 신뢰성 검증은 유인항공기를 이용한 비행시험과 차량에 탑재한 주행시험으로 수행되었다. DGNS와 비교 대상 위성관성항법장치는 GPS 위치와 관성센서 정보 등의 성능 확인을 통해 비교 검토되었다. 비행시나리오에 따른 유인항공기 비행시험을 통해 DGNS는 동급 상용제품에 대해 유사하거나 다소 우수한 성능과 신뢰성을 갖는 것으로 확인되었다. DGNS는 현재 스마트무인기에 탑재되어 비행시험 중이다.

• International Journal of Internet, Broadcasting and Communication
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• 제16권3호
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• pp.221-227
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• 2024

In autonomous navigation systems, the need for fast and accurate image processing using deep learning and advanced sensor technologies is paramount. These systems rely heavily on the ability to process and interpret visual data swiftly and precisely to ensure safe and efficient navigation. Despite the critical importance of such capabilities, there has been a noticeable lack of research specifically focused on ship image classification for maritime applications. This gap highlights the necessity for more in-depth studies in this domain. In this paper, we aim to address this gap by presenting a comprehensive comparative study of ship image classification using two distinct neural network models: the Feedforward Neural Network (FNN) and the Convolutional Neural Network (CNN). Our study involves the application of both models to the task of classifying ship images, utilizing a dataset specifically prepared for this purpose. Through our analysis, we found that the Convolutional Neural Network demonstrates significantly more effective performance in accurately classifying ship images compared to the Feedforward Neural Network. The findings from this research are significant as they can contribute to the advancement of core source technologies for maritime autonomous navigation systems. By leveraging the superior image classification capabilities of convolutional neural networks, we can enhance the accuracy and reliability of these systems. This improvement is crucial for the development of more efficient and safer autonomous maritime operations, ultimately contributing to the broader field of autonomous transportation technology.

• 한국해양공학회지
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• 제30권3호
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• pp.214-220
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• 2016

Imaging sonars such as side-scanning sonar or forward-looking sonar are becoming fundamental sensors in the underwater robotics field. However, using sonar images for underwater perception presents many challenges. Sonar images are usually low resolution with inherent speckled noise. To overcome the limited sensor information for underwater perception, we investigated preprocessing methods for sonar images and feature detection methods for a nonlinear scale space. In this paper, we focus on a comparative analysis of (1) preprocessing for sonar images and (2) the feature detection performance in relation to the scale space composition.