• Journal of the Korea Society of Computer and Information
• /
• v.13 no.4
• /
• pp.51-58
• /
• 2008

In this paper, we propose a place modeling based on the distribution of scale-invariant features, and a place recognition method that recognizes places by comparing the place model in a database with the extracted features from input data. The proposed method is based on the assumption that every place can be represented by unique feature distributions that are distinguishable from others. The proposed method uses global information of each place where one place is represented by one distribution model. Therefore, the main contribution of the proposed method is that the time cost corresponding to the increase of the number of places grows linearly without increasing exponentially. For the performance evaluation of the proposed method, the different number of frames and the different number of features are used, respectively. Empirical results illustrate that our approach achieves better performance in space and time cost comparing to other approaches. We expect that the Proposed method is applicable to many ubiquitous systems such as robot navigation, vision system for blind people, wearable computing, and so on.

• Journal of Digital Contents Society
• /
• v.16 no.6
• /
• pp.871-882
• /
• 2015

AIS-ASM is one of the studies to provide a variety of maritime safety information as well as the information on a ship's position that is their own function, and AIS-ASM has been implemented with adjustment of the relevant regulations since 2004. However, it was reported that the increased use of ASM message on the existing AIS channel affects the part of the existing AIS own function such as the transmission of the ship's position and safe-related information. Also, seamless MSP service is difficult to provide at a low transmission rate of the existing AIS channel. This study aims to reduce the marine officer's workload through automating captain's mandatory reporting items using the one of the next maritime digital communication technology (ASM2.0). For this purpose, we designed and realized the ASM2.0 protocol through analyzing domestic regulations about passenger flight and AIS-ASM message.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2018.10a
• /
• pp.217-219
• /
• 2018

The method on reconfiguring job priority in service queue has been developed to provide seamless service and to enhance operability of Data Service Platform(DSP) in Korean e-Navigation project that performed by Ministry of Oceans and Fisheries(MOF) since 2016. It plays a critical role for providing seamless services of DSP to expect which services ships request to DSP and how much time it costs to make services for responding them to ships in advance. Therefore, as developing a method on reconfiguring jobs in service queue of DSP with a noble algorithm to analyse priority index in parallel, DSP can provide seamless services to ships regardless of data volume and the number of requests that stacked in service queue.

• Information and Communications Magazine
• /
• v.17 no.1
• /
• pp.58-63
• /
• 2000

새 천년을 맞이하여 국내 이동전화 시장은 규모와 기술적 측면에서 놀랄만한 변화 를 겪게 될 것이다. 음성중심의 2세대 이동전화 서비스는 보급율이 50%를 넘어서며 포화수 준에 근접하고 있으며, 앞으로 무선데이타 통화량이 크게 증가하여 3~4년 후에는 총 통화량 의 50% 이상을 점유할 것으로 예측된다. 통신사업자들은 통신망의 광대역화와 글로벌화, IP Network 화를 더욱 강력하게 추진하고 있으며, 올 연말로 예정된 IMT-2000 사업자 선정은 이러한 추세를 더욱 가속화시킬 것으로 전망된다. 특히, 인터넷과 이동전화의 융화는 인간의 삶과 문화를 한순간에 변모시킬 혁명적 위력을 내포하고 있다. 정보화 시대를 향한 정보통 신업계의 대변혁이 그 절정을 향해 가속도를 붙이기 시작한 것이다. 신세기통신은 이러한 변화와 혼돈의 거친 물결 속에서 21세기 '정보통신 업계의 강자'로 도약하기 위한 힘찬 항해 를 진행하고 있다. 2000년 상반기까지 IS-2000시스템을 구축하여 최대 144kbps 수준의 고속 데이타 서비스를 제공하는 한편 i-TOUCH 017 컨텐츠 (Contents)를 한층 다양화, 첨단화 하는 등 본격적인 이동인터넷 사업을 전개해 나갈 것이다. 또 CDMA 국제 자동로밍 서비스 를 일본, 미국, 유럽 등 전세계로 확대하여 017 서비스의 글로벌화를 이룩할 계획이다. 이러 한 통신망 진화와 이동 인터넷 사업의 상당 부분을 SK텔레콤과 함께 추진하게 될 것이며 이러한 양사간의 전략적 제휴에 따른 시너지 효과는 오는 연말 IMT-2000 사업권의 성공적 확보로 이어질 것으로 기대된다. 21세기 정보통신산업은 광대역 통신망으로 대변되는 하드 웨어와 인터넷 컨텐츠로 대변되는 소프트웨어가 서로 융화되는 방향으로 발전할 것이다. 이에 따라 고객의 서비스 만족도나 사업자 선택 기준은 기존 통화물질 중심에서, 사업자가 제공하는 컨텐츠의 다양성이나 편리성으로 변화하는 것이 국적을 바꾸는 것보다 어려운 시 대가 멀지 않은 미래에 도래할 것이다. 신세기 통신 과 SK 텔레콤에는 현재 1,300만명이 넘 는 고객이 있으며. 이들 고객은 어 이상 음성통화 중심의 이동전화 고객이 아니라 신세기 통신과 SK텔레콤이 함께 구축해 나갈 거대란 무선 네트워크 사회에서 정보화 시대를 살아 갈 회원들이다. '컨텐츠의 시대'가 개막되는 것이며, 신세기통신과 SK텔레콤은 선의의 경쟁 과 협력을 통해 이동인터넷 서비스의 컨텐츠를 개발해 나가게 될 것이다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.2
• /
• pp.67-70
• /
• 2005

As the demand of sea leisure increases recently, interest is converged sea safety and offer of quick and systematic information according to weather environment that change rapidly. Use of Electronic Navigational Chart(ENC) in the sea in offer of geography information through Mobile terminal was gone to level that run in PDA environment in domestic by bulky good physician data information and complicated processing way of island in the sea expression in sea, and is loaded in obligatory sailing equipment of ship yet and is used. In this paper, we develop server system that take charge index for offer of quick information through Restrictive resource management and Caching Technique, image conversion and database construction and fast search to service various marine leisure informations of Weather Data and so on and image information of ENC in the sea to Mobile portable phone terminal efficiently.

• Journal of Korea Society of Industrial Information Systems
• /
• v.5 no.3
• /
• pp.38-43
• /
• 2000

Active radar reflector may be less familiar, since their uses have been limited to military applications, especially the enhancement of the effective radar cross-sections of missile test range in the drone aircraft and missiles. Perhaps the most widely-Down applications of radar transponders are Identification Friend or Foe(IFF) and its civilian counterpart secondary surveilliance radar for Air Traffic Control(ATC), and most recently, as Search And Rescue Transponder(SART) in the Global Maritime Distress and Safety System(GMDSS). Since it happens frequently accidents on the sea, the problems of the contamination more seriously considered. The conventional navigation buoy and utilities are not sufficient to maintain the safety of the sea and thus new structured concept must be considered. Therefore, this paper propose and implement the active radar reflector with a enhanced function. The results are shown that the performance of the system is significantly improved comparing with the conventional utilities.

• Korean Journal of Remote Sensing
• /
• v.13 no.2
• /
• pp.133-150
• /
• 1997

The purpose of this paper is to develop an algorithm of classification and interpretation of seafloor based on side scan sonar data. The algorithm consists of mosaicking of sonar data using navigation data, correction and compensation of the acouctic amplitude data considering the charateristics of the side scan sonar system, and segmentation of the seafloor using digital image processing techniques. The correction and compensation process is essential because there is usually difference in acoustic amplitudes from the same distance of the port-side and the starboard-side and the amplitudes become attenuated as the distance is increasing. In this paper, proposed is an algorithm of compensating the side scan sonar data, and its result is compared with the mosaicking result without any compensation. The algorithm considers the amplitude characteristics according to the tow-fish's depth as well as the attenuation trend of the side scan sonar along the beam positions. This paper also proposes an image segmentation algorithm based on the texture, where the criterion is the maximum occurence related with gray level. The preliminary experiment has been carried out with the side scan sonar data and its result is demonstrated.

• Journal of Advanced Navigation Technology
• /
• v.22 no.6
• /
• pp.665-669
• /
• 2018

In this paper, we design an antenna for LTE / Wi-Fi communication that operates in 2.65 GHz and 5 GHz band for small-sized broadband communication antenna that can be used in the sea. Microstrip patch antennas were chosen to improve the bandwidth. The slot width, length, and transmission line width were calculated using the theoretical formula for each step. In addition, we designed a microstrip antenna using CST Microwave Studio 2014 program that can design 3D. Simulation results show that the reflection lossis -12.712 dB at 2.65 GHz and -16.583 dB at 5 GHz. The gain was 1.738 dBi at 2.65 GHz and 3.284 dBi at 5 GHz. In this paper, we propose a dual-band antenna for LTE / Wi-Fi, which can be used in maritime environments, which is worse than terrestrial communication, because of differences in communication speed and communication stability compared with those used on land.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.25 no.1
• /
• pp.122-129
• /
• 2019

Due to its nature the manufacturing industry faces a cyclical economy, and therefore there is an urgent need for a companion industry to cope with this cyclic pattern in the long run. The sector suitable for meeting this demand is the repair and shipbuilding industry. In order to operate a shipbuilding repair business, a floating dock is indispensable, and most obsolete floating docks were imported from overseas and operated through repair/maintenance. However, there is no precise guideline for floating dock safety, and most models have been in use for at least 30 years without being required to enter classification at the time of operation. In this study, structural strength analysis was carried out using measured thickness information of aged floating docks, and the residual structural strength of floating docks in operation was analyzed. The main results derived from this study can be referred to as guidelines for the review of the structural safety of similar equipment, and it is expected that an optimal solution will be found within a short time using this method for repair/maintenance.

• Journal of Advanced Navigation Technology
• /
• v.23 no.3
• /
• pp.251-257
• /
• 2019

The configuration of ultra-long optical transmission link with dispersion management and optical phase conjugation is proposed. The whole transmission link consist of 80 km (single mode fiber span) ${\times}$ 56 fiber spans. The artificial distribution of single mode fibers' lengths and residual dispersions in fiber spans, which are gradually increased/decreased as the span number is increased, is adopted to compensate for the distorted wavelength division multiplexed channels. Since the compensation effect through the artificial distribution in the previous researches is expected to decrease as the number of fiber spans are increased, three-time repetition of the artificial distribution patterns at intervals of 9 fiber spans applied into the link with dispersion management and optical phase conjugation is proposed. From the simulation results, it is confirmed that the compensation in the link configured by the special distribution pattern among 4 proposed patterns is slightly improved than the link configured by the conventional method, which is designed by the repeat-less distribution pattern.