• Aerospace Engineering and Technology
• /
• v.3 no.2
• /
• pp.229-237
• /
• 2004

In this paper, the design method and algorithms of the signal processor for a multipurpose radar system are analyzed. The signal processor, operating at the two modes-collision avoidance mode and weather mode, has 4 steps of ADC, NCI, STC, CFAR. Several algorithms of NCI and CFAR are analyzed and the optimal design is proposed to the system. CVI and CMLD algorithm have good performance in decreasing the false alarm rate and increasing detection probability, Regarding processor computational capacity, K=12 for CVI, M=16~20, Ko=M-4 for CMLD is suggested. CVI processing needs much time, two or more processors need to be allocated to CVI. So, for the system with four processors, two processors should be allocated to VID of NCI with ADC input and CFAR with STC, and two processors are should be allocated to CVI.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.39 no.9
• /
• pp.848-857
• /
• 2011

Vision-based collision avoidance system for air traffic management requires a excellent multiple target detection algorithm under low signal-to-noise ratio (SNR) levels. The track-before-detect (TBD) approaches have significant applications such as detection of small and dim targets from an image sequence. In this paper, two detection algorithms with the TBD approaches are proposed to satisfy the multiple target detection requirements. The first algorithm, based on a dynamic programming approach, is designed to classify multiple targets by using a k-means clustering algorithm. In the second approach, a hidden Markov model (HMM) is slightly modified for detecting multiple targets sequentially. Both of the proposed approaches are used in numerical simulations with variations in target appearance properties to provide satisfactory performance as multiple target detection methods.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2020.11a
• /
• pp.548-551
• /
• 2020

최근 의료시장에 상용화된 모바일 수술 중 CT(intra-operative computed tomography, iCT)는 수술실 내 이동이 자유로울 뿐만 아니라 수술 후 즉각적인 환자 모니터링이 실시간으로 이루어져 수술 후 환자의 예후 향상과 재수술 확률을 낮출 수 있다. 이동성을 갖춘 iCT 는 편의성과 유용성이 검증되었지만, 이동시 발생될 수 있는 충돌사고의 단점이 존재한다. 따라서, iCT 의 이동시 발생할 수 있는 위험을 최소화 할 수 있는 안전장치가 요구된다. 본 연구에서는 모바일 iCT 의 구동 제어의 편의성과 안전성을 확보 할 수 있는 CT 촬영을 제어하기 위한 리모트 컨트롤러, 이동시 전방 시야를 확보하기 위한 전방 모니터링 카메라 출력, 충돌 위험을 알릴 수 있는 초음파 센서를 통합하는 임베디드 컨트롤러를 개발하고자 한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2000.10a
• /
• pp.278-283
• /
• 2000

As information communication technology developed we could check our blood pressure, pulsation electrocardiogram, SpO2 and blood test easily at home. To check our health at ordinary times is able though interlocking the house medical instrument with the wireless public data network This service will help the inconvenience to visit the hospital everytime and will save the individual's time and cost. In each house an organism data which is detected from the human body will be transmitted to the distance hospital and will be essentially applied through wireless public data network The medical information transmit system is utilized by wireless close range network It would transmit the obtained organism signal wirelessly from the personal device to the main center system in the hospital. Remote telemetry system is embodied by utilizing wireless media access protocol. The protocol is embodied by grafting CSMA/CA(Carrier Sense Multiple Access with Collision Avoidance) protocol falling mode which is standards from IEEE 802.11. Among the house care telemetry system which could measure blood pressure, pulsation, electrocardiogram, SpO2 the study embodies the ECC(electrocardiograph) measure part. It within the ECC function into the movable device and add 900㎒ band wireless public data interface. Then the aged, the patients even anyone in the house could obtain ECG and keep, record the data. It would be essential to control those who had a health-examination heart diseases or more complicated heart diseases and to observe the latent heart disease patient continuously. To embody the medical information transmit system which is based on wireless network. It would transmit the ECG data among the organism signal data which would be utilized by wireless network modem and NCL(Native Control Language) protocol to contact through wireless network Through the SCR(Standard Context Routing) protocol in the network it will be connected to the wired host computer. The computer will check the recorded individual information and the obtained ECC data then send the correspond examination to the movable device. The study suggests the medical transmit system model utilized by the wireless public data network.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.53 no.2
• /
• pp.177-186
• /
• 2017

This study is intended to provide navigator with specific information necessary to assist in the avoidance of collision and in operation of ships to evaluate the maneuverability of research vessel Jera. Authors carried out full-scale sea trials for turning test, zig-zag test, and spiral test at actual sea-going condition, which were performed on starboard and port sides with 10-20 rudder angle at service speed of 10 knots. The turning circle was much different at both of the turning of port and starboard which was longer at the starboard than at the port. In the zig-zag test results, the port and starboard was $10^{\circ}$ the first and second overshoot angles were $6.0^{\circ}$, $5.8^{\circ}$ and $6.3^{\circ}$, $7.1^{\circ}$ respectively and the first overshoot angles were $16.4^{\circ}$, $17.6^{\circ}$ when using $20^{\circ}$. Her maneuverability index T and N can be easily determined by using an analogue computer with the data obtained from the zig-zag tests where K is a constant representing the turning ability and T is a constant representing her quick response. In the zig-zag tests under $10^{\circ}$ or $20^{\circ}$ at rudder angle, the value K is 0.149. 0.123 sec- and T is 11.853 and 6.193 sec and angular velocity is $0.937^{\circ}/sec$ and $1.636^{\circ}/sec$. In the spiral test, the loop width was unstable at $+0.51^{\circ}$ and $-1.19^{\circ}$ around the midship of rudder, but the tangent line at $0^{\circ}$ was close to vertical. From the sea trial results, we found that she did comply with the present criterion in the standards of maneuverability of IMO.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.21 no.9
• /
• pp.1788-1795
• /
• 2017

In this paper, we proposed a service that provides CPA/TCPA information to ships, without ARPA/ATA devices to support decision making of the navigator for maritime safety based on various services at shore and off-shore. To verify the proposed service, we use SiNAS (scenario-based simulator for NAS) with CPA/TCPA information providing software to evaluate its usability, because executing the test in real ship has many limitations and difficulties. To do this, we specify two simulation scenarios for the required purpose, and we liaise twelve participants with various navigation experience to conduct the simulations. Also, we analyze the results of simulation using mission success or not, the minimum approaching distance with the target ship, the time of a recognition the target ship, the time of a first action for collision avoidance with the target ship, and so on. Then, we evaluate usability of the proposed service based on the three elements which are effectiveness, efficiency and satisfaction.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.19 no.6
• /
• pp.222-234
• /
• 2020

Autonomous vehicles are equipped with a wide rage of sensors such as GPS, RADAR, LIDAR, camera, IMU, etc. and are driven by recognizing and judging various transportation systems at intersections in the city. The accident ratio of the intersection of the autonomous vehicles is 88% of all accidents due to the limitation of prediction and judgment of an area outside the sensing distance. Not only research on non-signalized intersection collision avoidance strategies through V2V and V2I is underway, but also research on safe intersection driving in failure situations is underway, but verification and fragments through simple intersection scenarios Only typical V2V failures are presented. In this paper, we analyzed the architecture of the V2V module, analyzed the causal factors for each V2V module, and defined the failure mode. We presented intersection scenarios for various road conditions and traffic volumes. we used the ISO-26262 Part3 Process and performed HARA (Hazard Analysis and Risk Assessment) to analyze the risk of autonomous vehicle based on the simulation. We presented ASIL, which is the result of risk analysis, proposed a monitoring concept for each component of the V2V module, and presented monitoring coverage.

• Journal of Korean Society of Transportation
• /
• v.22 no.4 s.75
• /
• pp.147-158
• /
• 2004

A class of SWP(Stochastic Wane Propagation) models microscopically mimics individual vehicles' stochastic behavior and traffic jam propagation with simplified car-following models based on CA(Cellular Automata) theory and macroscopically captures dynamic traffic flow relationships based on statistical physics. SWP model, a program-oriented model using both discrete time-space and integer data structure, can simulate a huge road network with high-speed computing time. However, the model has shortcomings to both the capturing of low speed within a jam microscopically and that of the density and back propagation speed of traffic congestion macroscopically because of the generation of spontaneous jam through unrealistic collision avoidance. In this paper, two additional rules are integrated into the NaSch model. The one is SMR(Stopping Maneuver Rule) to mimic vehicles' stopping process more realistically in the tail of traffic jams. the other is LAR(Low Acceleration Rule) for the explanation of low speed characteristics within traffic jams. Therefore, the CA car-following model with the two rules prevents the lockup condition within a heavily traffic density capturing both the stopping maneuver behavior in the tail of traffic jam and the low acceleration behavior within jam microscopically, and generates more various macroscopic traffic flow mechanism than NaSch model's with the explanation of propagation speed and density of traffic jam.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.47 no.6
• /
• pp.10-21
• /
• 2010

In the cluster-tree network which covers wide area network and has many nodes for monitoring purpose traffic is concentrated around the sink. There are long transmit delay and high data loss due to the intensive traffic when IEEE 802.15.4 is adapted to the cluster-tree network. In this paper we propose Dynamic Channel Allocation algorithm which dynamically allocates channels to increase the channel usage and the transmission success rate. To evaluate the performance of DCA, we assumed the monitoring network that consists of a cluster-tree in which sensing data is transmitted to the sink. Analysis uses the traffic data which is generated around the sink. As a result, DCA is superior when much traffic is generated. During the experiment assuming the least amount of traffic, IEEE 802.15.4, has the minimum length of active period and 90% data transmission success rate. However DCA maintains 11.8ms of active period length and results in 98.9% data transmission success rate.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.5
• /
• pp.557-565
• /
• 2021

Path-following control is considered as one of the most fundamental skills to realize autonomous navigation of marine vessels in the ocean. This study addresses with the path-following control for a ship in which there are environmental disturbances in the directions of the surge, sway, and yaw motions. The guiding principle and back-stepping method was utilized to solve the ship's tracking problem on the reference path generated by a virtual ship. For path-following control, error dynamics is one of the most important skills, and it extends to the research fields of automatic collision avoidance and automatic berthing control. The algorithms for the guiding principles and error variables have been verified by numerical simulation. As a result, most error variables converged to zero values with the controller except for the yaw angle error. One of the most interesting results is that the tracking errors of path-following control between two ships are smaller than the existing safe passing distances considering interaction forces from near passing ships. Moreover, a trade-off between tracking performance and the ship's safety should be considered for determining the proper control parameters to prevent the destructive failure of actuators such as propellers, fins, and rudders during the path-following of marine vessels.