• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.560-565
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• 2016

최근 대형 컨테이너선의 개발이 지속적으로 이루어짐에 따라 슬래밍에 의한 선수 및 선미의 구조안정성 문제가 대두되고 있지만 설계 단계에서 슬래밍에 대해 고려하기에는 현상의 복잡성으로 인해 어려움이 많았다. 이를 위해 KRISO에서 시행된 WILS JIP의 선수 단면 형상 및 선미 단면인 쐐기 형상으로 격자를 생성하여 EDISON CFD 다상유동 해석자를 통해 수치해석을 시도하였다. 기존 방식과 달리 계산 시간 절감을 위하여 격자 변형 기법을 적용하지 않고 모형 시험결과를 기반으로 한 유입류 조건을 설정하여 입수 충격 문제를 해석해보았다. 그 결과, 선미 형상의 경우 선행연구와 유사하게 실험 결과에 근접한 유체 충격력을 정량적으로 얻어낼 수 있었다. 선수 형상의 경우에서는 구상 선수로 인해 파생되는 센서 위치별 충격력의 변화를 확인할 수 있었으며, 실제 유동에 가까운 유동 형상과 슬래밍에 의한 충격력을 개략적으로 구할 수 있었다.

• 한국IT서비스학회:학술대회논문집
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• 2006.05a
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• pp.181-185
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• 2006

최근 차량에 설치된 단말기를 통해 길안내 서비스, 교통정보 서비스 등 다양한 정보를 제공하는 텔레매틱스 서비스가 활발하게 연구되고 있다. 하지만 현재 대다수의 텔레매틱스 서비스는 최대 15m 의 공간오차를 가진 GPS 기술을 이용하기 때문에 차량의 정확한 위치정보를 파악하기는 힘들다. 따라서 본 논문에서는 무선 센서노드를 이용해 GPS 보다 정확한 차량의 위치정보와 속도를 감지하고 노드 간 통신 프로토콜로서 Telematics Scheduling Protocol(TSP)[1]을 사용하여 교차로 중앙에 위치한 베이스 스테이션으로 전송하여 교차로에서 발생할 수 있는 차량 충돌을 예측하며 충돌 위험 정보를 교차로에 근접한 자동차에게 알려주는 텔레매틱스 교통안전시스템[1]을 소개한다. 또한 교통안전시스템으로서의 신뢰성과 실시간성을 비교평가하기 위하여 TSP 프로토콜, IEEE 802.11[2]과 802.15.4[3]를 대상으로 네트워크 시뮬레이터 ns-2[4]를 이용하여 시뮬레이션한다.

• Journal of the Korean institute of surface engineering
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• v.52 no.5
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• pp.239-245
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• 2019

To increase the throughput of tip-based nanolithography (TBN), one approach is to use a large array of such tips working in parallel. It is important to maintain co-planarity between the tip array and the writing surface. A slight misalignment can cause large discrepancies of contact force and feature sizes. We report a capacitive proximity sensor built-in with the TBN array for leveling an arrayed polymer pen array. The device allows alignment between an array of writing tips and the writing substrate without contact and contamination. The angular sensitivity of the sensor is $0.05^{\circ}$ for an array with maximum tip-to-tip separation of 100 mm.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2020.11a
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• pp.131-132
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• 2020

자율운항선박 지원 6종서비스는 자율운항선박의 도입에 따른 항계 및 협수로 내에서 터미널까지 안정적으로 통항과 자율적인 이·접안 및 화물 적·하역이 가능하도록 안전운항을 지원하는 기술을 의미한다. 자율운항선박 지원 6종서비스에는 근접 선박에 대한 연속 회피가 가능한 자율운항 지원 서비스, 인공지능 센서 융합을 통한 접·이안 및 계류 지원 서비스, 스마트 해상 물류 프로세스를 위한 화물 양·적하 및 선박 입출항 지원 서비스, PSC 점검율 제고를 위한 PSC 점검 지원 서비스, 선박의 주요 기기를 육상에서 관찰하기 위한 상태모니터링 지원 서비스, 해양사고 발생 시 신속한 조치를 위한 사고대응 지원 서비스로 이루어져 있다. 이 연구에서는 개발되는 안전운항 지원서비스 6종의 실용성 및 현장 적용 가능성을 테스트하기 위한 실선박 기반의 검증 시나리오를 개발하고 6종 서비스의 육상 시범 운용을 위한 인프라를 구축하고자 하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.292-297
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• 2016

This paper presents a navigation problem for an autonomous mobile robot in an unknown environment. The environment contains various types of obstacles and is completely unknown to the robot. Therefore, all of the surrounding information must be detected by the robot's proximity sensors. A navigation method was developed based on a fuzzy inference system to guide the robot to move along a collision-free path and reach the goal position quickly. The obstacles are assumed to be static, and both regular and irregular types of obstacles were investigated. A wall following method is also proposed for a special environment that contains a labyrinth or sharp U-valley obstacles. Simulation results demonstrate that the proposed method has great potential for this navigation problem.

• Journal of Convergence for Information Technology
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• v.10 no.5
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• pp.111-116
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• 2020

Recently, many safety accidents involving children shuttle buses take place. Without a teacher for help, a safety accident occurs when the driver can't see a child who is getting off in the blind spot of both frontside and backside. A deep learning-based smart mirror allows user authentication and provides various services. Especially, It can be a role of helper for children, and prevent accidents that can occur when drivers or assistant teachers do not see them. User authentication is carried out with children's face registered in advance. Safety accidents can be prevented by an approximate sensor and a camera in frontside and backside of the bus. This study suggests a way of checking out whether children are missed in the process of getting in and out of the bus, designs a system that reduce blind spots in the front and back of the vehicle, and builds a safety system that provide various services using GPS.

• Journal of the Korean Institute of Intelligent Systems
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• v.27 no.2
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• pp.132-137
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• 2017

Drone is currently used for wide application areas in our real life. Also it performs more important functions. We propose a method of drone operation system for the prevention of industrial disaster. In normal operation of drone system the drone monitors the industrial sites according to the planned flight path with acquiring the monitored images and send the image information to the server. The server analyzes and compares the images to DB information by calculating the similarity based on the threshold. Then the system decides whether the industrial sites has problems or not. If the abnormal condition is occurred, the drone change the flight path to abnormal flight path and keep monitoring the industrial sites with measuring the air status by sensors and sends all information to server system on the ground. If the emergency case is occurred, drone approaches the closest position of accident points and acquiring the all information and send them to server and 119 center.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.2
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• pp.213-219
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• 2013

Recently, with the rapid advancement in information and communication technology, indoor location-based services(LBSs) that require precise position tracking have been actively studied with outdoor-LBS using GPS. However, in case of a ship which consists of steel structure, it is difficult to measure a precise localization due to significant ranging error by the diffraction and refraction of radio waves. In order to reduce location measurement errors that occur in these indoor environments, this paper presents distance compensation algorithms that are suitable for a narrow passage such as ship corridors without any additional sensors by using UWB(Ultra-wide-band), which is robust to multi-path and has an error in the range of a few centimeters in free space. These improvement methods are that Pythagorean theory and adjacent node technique are used to solve the distance error due to the node deployment and distance variation analysis technique is applied to reduce the ranging errors which are significantly fluctuated in the corner section. The experimental results show that the number of nodes and the distance error are reduced to 66% and 57.41%, respectively, compared with conventional CSS(Chirp spread spectrum) method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.10
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• pp.2071-2078
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• 2009

In this paper, we proposed a non-contact respiration measurement system with ultrasonic proximity sensor. Ultrasonic proximity sensor approach of respiration measurement which respiration signatures and rates can be derived in real-time for long-term monitoring is presented. 240 kHz ultrasonic sensor has been applied for the proposed measurement system. The time of flight of sound wave between the transmitted signal and received signal have been used for a respiration measurement from abdominal area. Respiration rates measured with the ultrasonic proximity sensor were compared with those measured with standard techniques on 5 human subjects. Accurate measurement of respiration rate is shown from the 50 cm measurement distance. The data from the method comparison study is used to confirm the performance of the proposed measurement system. The current version of respiratory rate detection system using ultrasonic can successfully measure respiration rate. The proposed measurement method could be used for monitoring unconscious persons from a relatively close range, avoiding the need to apply electrodes or other sensors in the correct position and to wire the subject to the monitor. Monitoring respiration using ultrasonic sensor offers a promising possibility of non-contact measurement of respiration rates. Especially, this technology offers a potentially inexpensive implementation that could extend applications to consumer home-healthcare and mobile-healthcare products. Further advances in the sensor design, system design and signal processing can increase the range of the measurement and quality of the rate-finding for broadening the potential application areas of this technology.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.11C
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• pp.1498-1509
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• 2004

In this paper, we evaluate the performance of a noncoherent OOK (On-Off Keying) UWB (Ultra Wide Band) system based on power detection with noise power calibration and noise power windowing for ubiquitous sensor network applications in typical indoor wireless channels. Utilizing noise power calibration and noise power windowing, the current noise information can be initially or adaptively provided to determine suitable detection threshold value for signal demodulation. Simulation results show that the noncoherent OOK UWB system using noise power calibration achieves good BER (Bit Error Rate) performance which is favorably comparable to that of the system using the ideal adaptive threshold, while maintaining simple receiver structure. However, despite the serious loss of the data transmission rate, the performance improvement by noise power windowing is not so remarkable. furthermore, these performance results are similarly maintained in BEE 802.15 Task Group 3a UWB indoor channel model, and it is also revealed that the BER performance can be significantly improved by increasing the pulse repetition rate.