• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2013년도 추계학술대회
• /
• pp.597-600
• /
• 2013

본 논문은 해상통신 환경의 현대화를 위해서 기존 통신시스템을 아날로그에서 디지털로 대체하고 새로운 통신기술을 도입하기 위한 시스템의 기술적 특성을 연구하고 이러한 시스템이 국제적으로 조화된 주파수에서 디지털 통신을 효율적으로 할 수 있는 새로운 주파수 대역 확보 및 기존 할당된 주파수 조정 등에 관해서 국제 표준화기구의 최근 연구 동향을 분석해서 기술하였다. 특히 국제전기통신연합 무선통신부문(ITU(International Telecommunication Union)-R(Radiocommunication sector))에서는 IMO(International Maritime Organization)와 IEC(International Electrotechnical Commission)와 긴밀한 협력으로 결과를 도출해서 해상통신 현대화를 추진하고 있다. 본고에서는 ITU-R의 해상통신 현대화를 위한 최근 회의 결과(WP(Working Party)5B회의, WRC(World Radiocommunication Conference)-12 결과 등)를 분석해서 기술하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
• /
• pp.381-382
• /
• 2007

Recently fishing industry is interested in efficient and automated fishing implementations to reach the level of the international leading technology. One of the important device used in fishing boat is an automated electric compass that harnesses the GPS and terrestrial magnetic sensor. The electric compass is desired to be minimized in size while keeping a high effectiveness in the characteristic of a magnetic compass. This device also can be used as a heading angle sensor to construct auto-navigation system in a small size of ships. However, there exists measurement errors induced from the slope of terrestrial magnetic sensor caused by the motion of boat. In this paper, a method has been proposed removing the measurement error arising from the slope of terrestrial magnetic sensor when the ship is in motion. We have designed a sensor with two DOF(degree of freedom) and a weight to maintain the horizontality of the sensor. Through this research, the hardware has been designed and also a test has been performed. The test shows a promissory result.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제9권2호
• /
• pp.185-198
• /
• 2017

The application of composites as an alternative material for marine steel hatch covers is the subject of this study. Two separate approaches are considered; weight reduction approach and strengthening approach. For both approaches Finite Element Analysis (FEA) was performed using ANSYS software. Critical design parameters of the composite hatch cover and FEA are discussed in details. Regarding the weight reduction approach; steel hatch covers of a bulk carrier were replaced by composite covers and a weight reduction of 44.32% was achieved leading to many benefits including fuel saving, Deadweight Increment and lower center of gravity of the vessel. For the strengthening approach; the foremost hatch cover was strengthened to withstand 150% of the load required by IACS for safer navigation while no change in weight was made between the steel and composite covers. Results show that both approaches are feasible and advantageous.

• 한국안전학회지
• /
• 제24권4호
• /
• pp.104-110
• /
• 2009

In this driving simulation study, the impairing effects of various types of electronic devices usage(i. e., destination search by using in-vehicle navigation system, TV watching and dialing cellular phone) during driving on front-to-rear-end collision avoidance were investigated. Percentage of collisions, driving speeds when the drivers collided, and initial reaction time for collision avoidance were analyzed and compared as the dependent measures. The results indicated that (1) any types of electronic devices usage during driving induced more serious collision-related impairment than control condition where no additional task was required, and (2) in general, destination search task appeared to impair drivers collision avoidance performance more than the other task requirements in terms of percentage of collisions and initial reaction time for collision avoidance, but TV watching induced most serious collision impact. These results suggested that any types of electronic device usage could distract drivers attention from the primary task of driving, and be resulted in serious outcome in potentially risky situation of front-to-rear-end collision. In particular, mandatory use of eye-hand coordination and receiving feedback seemed to one of essential factor leading the drivers visual attentional distraction.

• 한국정보통신학회논문지
• /
• 제11권8호
• /
• pp.1450-1455
• /
• 2007

최근의 고성능 카 오디오는 고음질과 다양한 음원입력 신호를 처리하기 위해 전용의 신호처리 칩을 사용하는 추세이다. 본 논문에서는 이러한 카 오디오 전용 DSP인 필립스의 SAF7730을 사용한 고성능 카 오디오 설계시에 유용하게 사용할 수 있는 개발 도구를 제작하였다. 이 개발 도구는 윈도우 운영 체제에서 동작하는 설정 GUI프로그램과 통신 인터페이스 보드로 구성되어 있다. 설정 GUI프로그램은 사용자가 SAF7730에 내장된 신호처리 기능의 설정을 손쉽게 할 수 있도록 구성되어 있으며, 통신 인터페이스 보드는 설정 프로그램과 SAF7730간의 통신 프로토콜 및 데이터 포맷의 변환을 처리하도록 제작하였다. 본 논문에서 개발한 시스템은 실제 상품화된 카 오디오 설계에 적용되어 그 유용성을 입증하였다.

• 대한원격탐사학회지
• /
• 제19권1호
• /
• pp.91-97
• /
• 2003

The design of Graphic Information System(GIS) in various applications is suffering from the difficulty of data acquisition, which is labor-intensive and time consuming. In order to provide the spatial data rapidly and accurately, 4S-Van, a prototype mobile mapping system, has been developed. The 4S-Van consists of 1)Global Positioning System(GPS), Inertial Navigation System(INS) for estimating the geographic position and attitude of the moving van, i.e.,(x, y, z) and the direction of the Van, 2) Charge Coupled Device(CCD) camera and laser scanner for capturing images and for measuring depth from geographic objects, and 3) External Synchronization Device(ESD) and industrial PC for synchronizing data from GPS/INS/CCD camera and for storing the data. In this paper, we present the design and implementation of the proto-Dpe 4S-Van system for spatial data acquisition for various GIS applications.

• Brain Tumor Research and Treatment
• /
• 제6권2호
• /
• pp.78-81
• /
• 2018

Gliosarcoma (GS), known as variant of glioblastoma multiforme, is aggressive and very rare primary central nervous system malignant neoplasm. They are usually located in the supratentorial area with possible direct dural invasion or only reactive dural thickening. However, in this case, GS was located in lateral side of left posterior cranial fossa. A 78-year-old man was admitted to our hospital with 3 month history of continuous dizziness and gait disturbance without past medical history. A gadolinium-enhanced MRI demonstrated $5.6{\times}4.8{\times}3.2cm$ sized mass lesion in left posterior cranial fossa, heterogeneously enhanced. The patient underwent left retrosigmoid craniotomy with navigation system. The tumor was combined with 2 components, whitish firm mass and gray colored soft & suckable mass. On pathologic report, the final diagnosis was GS of WHO grade IV. In spite of successful gross total resection of tumor, we were no longer able to treat because of the patient's rejection of adjuvant treatment. The patient survived for nine months without receiving any special treatment from the hospital.

• 한국측량학회지
• /
• 제39권5호
• /
• pp.289-295
• /
• 2021

Recently, owing to the development of autonomous vehicles, research on precisely determining the position of a moving object has been actively conducted. Previous research mainly used the fusion of GNSS/IMU (Global Positioning System / Inertial Navigation System) and sensors attached to the vehicle through a Kalman filter. However, in recent years, new technologies have been used to determine the location of a moving object owing to the improvement in computing power and the advent of deep learning. Various techniques using RNN (Recurrent Neural Network), LSTM (Long Short-Term Memory), and NARX (Nonlinear Auto-Regressive eXogenous model) exist for such learning-based positioning methods. The purpose of this study is to compare the precision of existing filter-based sensor fusion technology and the NARX-based method in case of GNSS signal blockages using simulation data. When the filter-based sensor integration technology was used, an average horizontal position error of 112.8 m occurred during 60 seconds of GNSS signal outages. The same experiment was performed 100 times using the NARX. Among them, an improvement in precision was confirmed in approximately 20% of the experimental results. The horizontal position accuracy was 22.65 m, which was confirmed to be better than that of the filter-based fusion technique.

• 한국기계가공학회지
• /
• 제19권10호
• /
• pp.68-73
• /
• 2020

The proportion of airline accidents caused by human factors is steadily increasing. The aviation industry has made considerable progress in reducing the accident rate; however, since the early 1980s, the accident rate has remained constant. Due to airspace congestion, the safety margins of these existing safety promotion methods are gradually decreasing; thus, new methods to prevent accidents and quasi-accidents must be devised. Causative factors of aviation accidents include increased air traffic due to increased air demand, increased cumulative working hours due to long-distance flights, and complicated flight environments. Accidents often occur when several small errors accumulate in the normal course of operation, rather than after a single error. Accordingly, in this study, the impacts on air navigation due to human error by aviation maintenance personnel and varying international standards (i.e., KOCA vs. F.A.A vs. EASA) analyzed, and the relationship between human decision-making and behavior was investigated. The resulting safety analysis and alternatives were presented to prevent aviation maintenance accidents and cognitive ergonomics errors.

• 해양환경안전학회지
• /
• 제28권3호
• /
• pp.441-450
• /
• 2022

The introduction of autonomous underwater gliders (AUGs) specifically addresses the reduction of operational costs that were previously prohibited with conventional autonomous underwater vehicles (AUVs) using a "scaling-down" design philosophy by utilizing the characteristics of autonomous drifters to far extend operation duration and coverage. Long-duration, wide-area missions raise the cost and complexity of in-water testing for novel approaches to autonomous mission planning. As a result, a simulator that supports the rapid design, development, and testing of autonomy solutions across a wide range using software-in-the-loop simulation at faster-than-real-time speeds becomes critical. This paper describes a faster-than-real-time AUG simulator that can support high-resolution bathymetry for a wide variety of ocean environments, including ocean currents, various sensors, and vehicle dynamics. On top of the de facto standard ROS-Gazebo framework and open-sourced underwater vehicle simulation packages, features specific to AUGs for ocean mapping are developed. For vehicle dynamics, the next-generation hybrid autonomous underwater gliders (Hybrid-AUGs) operate with both the buoyancy engine and the thrusters to improve navigation for bathymetry mappings, e.g., line trajectory, are is implemented since because it can also describe conventional AUGs without the thrusters. The simulation results are validated with experiments while operating at 120 times faster than the real-time.