• Journal of Advanced Navigation Technology
• /
• v.20 no.4
• /
• pp.380-385
• /
• 2016

Shadows are common phenomena observed in natural scenes and often bring a major problem that is affected negatively in colour image analysis. It is important to detect the shadow areas and should be considered in the pre-processing of computer vision. In this paper, the method of shadow detection is proposed using cross entropy and intensity image, and is performed in single image based on the satellite images. After converting the color image to a gray level image, the shadow candidate region has been estimated the optimal threshold value by cross entropy, and then the final shadow region has been detected using intensity image. For the validity of the proposed method, the satellite images is used to experiment. Some experiments are conducted so as to verify the proposed method, and as a result, shadow detection is well performed.

• Journal of Advanced Navigation Technology
• /
• v.18 no.5
• /
• pp.429-436
• /
• 2014

This paper proposes three methods of the time synchronization for Pseudolite and GPS and analyzes pseudolite time synchronization error factors for software based performance evaluation on proposed time synchronization methods. Proposed three time synchronization methods are pseudolite time synchronization station construction method, method by using UTC(KRIS) clock source and GPS timing receiver based time synchronization method. Also, we analyze pseudolite time synchronization error factors such as errors of pseudolite clock and reference clock, time delay as clock transmission line, measurement error of time interval counter and error as clock synchronization algorithm to design simulation platform for performance evaluation of pseudolite time synchronization.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.1
• /
• pp.56-67
• /
• 2018

With the introduction of the maritime safety supervisor system in Korea following the passenger vessel Sewol accident, the safety control system for coastal vessels has been reinforced. A maritime safety supervisor performs marine accident prevention activities by offering periodical or occasional guidance and supervision. When a deficiency is found during guidance or supervision sessions, an order for improvement is issued to rectify the problem by such measures as supplementation or replacement of vessel facilities, improvement of work hours and working conditions for employees, educational and training programs for executives and employees, or the improvement of other affairs relating to maritime safety control. However the present order for navigation suspension by a maritime safety supervisor is limited solely to supplementation or replacement. For this reason, orders for navigation suspension against other facilities is impossible, even if a serious deficiency that could lead to a marine accident such as poor cargo loading conditions or unqualified crew is identified. Therefore, the order for vessel navigation suspension to secure seaworthiness should be expanded to include cargo loading/unloading operations, certificates and documentation, maritime safety management systems, and human elements including emergency drills and working conditions, in addition to the supplementation or replacement of vessel facilities that exists.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2010.10a
• /
• pp.161-163
• /
• 2010

말하기는 곧 행위라는 주장이 화용론의 핵심명제이다. VTS 대화는 선박들의 효율적이고 안전한 항해를 위해 이루어지는 언어적 상호작용 행위이다. 본 연구에서는 모든 VTS 화행은 항해행위의 수행에 따른 부수적인 요소가 아니라 필수불가결한 요소라는 점에 주목하고자 하였다. 먼저 화용론에서 다루는 대화의 협력원칙, 공손원칙, 명령화행 및 약속화행의 적정성, 최소대화의 원칙을 VTS 대화 상황에 적용하여 VTS 화행의 특성을 정립하고자 하였다. 그리고 실제 발생했던 해양사고에서 선박 간 담화 또는 대화를 분석함으로써 화용론적 실패가 충돌사고에 어떻게 영향을 끼치는지를 검토해보았다. VTS 상황에서 이루어지는 담화 또는 대화분석을 통해 해양사고의 원인을 심도 있게 분석하는 방안과 이의 결과를 항해사 및 관제사 교육에 활용하는 방안을 제시하였다. 덧붙여서 co-Navigation 개념이 항해안전의 새로운 패러다임이 되어야 한다는 것을 주장하였다.

• Journal of Advanced Navigation Technology
• /
• v.12 no.4
• /
• pp.384-391
• /
• 2008

These days, along with the information society, the value of information has emerged as a powerful factor for a company's development and sustainability, and therefore, the importance of the Information Security and Management System (ISMS) has emerged and become an integral part of all areas of business. In this paper, ISMS evaluation methods from around the world are compared and analyzed with the standards of various management guidelines, definitions, management of threats and vulnerability, approaches to result calculations, and the evaluation calculation indexes for domestic to propose the best method to evaluate the Information Security Management System that will fit the domestic environment.

• Journal of Advanced Navigation Technology
• /
• v.14 no.4
• /
• pp.504-511
• /
• 2010

The personal bio-information supplied from the PHD(Personal Health Device) for personal health management is very sensitive in relation to a personal living body in an aspect of privacy protection. On the assumption thai the information is about a patient, it is more serious problem if it is revealed to a third party. However. the established ISO (International Organizations for Standardization) standard protocol[1] in October 2009 has just considered a transmission part for mutual exchange of bio-information between individuals, but has never actually considered security elements. Accordingly, this paper is to show all sorts of security threats according to personal health management in the u-health environment and security requirements newly.

• Journal of Advanced Navigation Technology
• /
• v.7 no.2
• /
• pp.191-198
• /
• 2003

In this paper, we analyze the performance of transmit diversity techniques which are the key technologies of the third generation mobile communication systems. Transmit diversity techniques adopted on the specification of 3GPP are classified into open-loop and closed-loop methods depending on the existence of feedback data. In WCDMA systems, the DPCH signal is space-time coded to provide a mobile station with diversity. Computer simulations shall be performed to analyze and compare their performance considering the effect of mobile speed, number of path, power control, and delay of feedback with the WCDMA slot format #13 for application to WCDMA systems.

• Journal of Advanced Navigation Technology
• /
• v.14 no.5
• /
• pp.604-609
• /
• 2010

The tactical datalink system has been recognized as the key element in Network Centric Warfaret(NCW). The military has been putting great efforts into establishing datalink system using existing tactical radio and UMPC. but the aircraft operational environment and the requirement specification for equipments mounted in the avionics are differentiated with those in other platforms, so special efforts are needed to select suitable UMPC. In this paper, we consider the requirement analysis for UMPC in respect of processor performance, operation system (OS) and NVG compatibility. Additionally we have to make a effort to understand the operational environment of aircraft and examine th standard to select the appropriate UMPC, and then we expect to establish the tactical datalink system successfully.

• Journal of Advanced Navigation Technology
• /
• v.19 no.2
• /
• pp.91-97
• /
• 2015

This paper specifies several considerations about assessing safety-critical software in the aerospace domain. In order to evaluate safety critical software in the aerospace industry, it is required to identify an information of evaluation criteria of software under evaluation. The information is specified in the standard, but determination of evaluation criteria cannot be decided by itself and depends on the results of safety assessment of a system and system design. Thus, this paper explains required information of system development standard and safety assessment standard to determine software evaluation criteria. It surveys existing methodologies about evaluating software, and suggests method which is adapted to evaluation of an advanced surface movement guidance and control system (A-SMGCS) software.

• Journal of Advanced Navigation Technology
• /
• v.24 no.4
• /
• pp.267-272
• /
• 2020

In order to monitor in large area of a ship without any concerns of spacial environments, there can be the use of many sensors that support wireless network technologies. Through the deployment of the wireless sensors and their autonomous network formations, the status of a ship can be easily monitored in real time. Moreover, if all the sensors are timely synchronized with each other, the locations and the moving directions of certain events can be estimated. Thus, the time synchronization amongst wireless sensors are crucial. In this paper, we propose an algorithm which supports reduced message transmissions between the sensors for synchronization.