• Journal of Navigation and Port Research
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• v.33 no.1
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• pp.43-50
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• 2009

Recently, many maritime accidents have been increased and the collisions due to human error are given a great deal of proportions out of them We develop the Real-time Collision Risk Monitoring System (CRMS) for the navigational officers to cope with the emergency situation promptly and thus to reduce the probability of casualty. In this study, the risk of collision and grounding is evaluated by two kinds of method. The first method is based on Fuzzy algorithm, which evaluates the risk of collision between traffic ships. The second method is based on Environmental Stress (ES) Model, where the total risk of collision and grounding is evaluated by the environmental stress felt by human. The developed real-time CRMS has been installed to the ship handling simulator system and its capabilities have been tested through simulator experiments.

• Journal of Korea Spatial Information System Society
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• v.10 no.3
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• pp.45-54
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• 2008

This paper designs and Implements a connectivity analyzer for the hybrid vehicular network based on the real-life movement history data achieved from the Taxi telematics system currently in operation, aiming at providing a useful guideline and information to build a telematics network. The simulator traces the location of each vehicle, sets the vehicle type, either gateway or normal, decides whether it can be connected to a mobile gateway, keeps track of status of the vehicle, and calculates the duration of disconnected state. With this analysis considering the transmission range and gateway ratio, we can decide the cost-effective number of mobile gateways having both cellular and ad-hoc network interfaces, and buffer space requirement based on the measured disconnection time and message generation ratio.

• Journal of Korea Multimedia Society
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• v.12 no.8
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• pp.1155-1163
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• 2009

This paper proposes an automatic facial expression generation system of vector graphic character using gaussian process model. Proposed method extracts the main feature vectors from twenty-six facial data of character redefined based on Russell's internal emotion state. Also by using new gaussian process model, SGPLVM, we find low-dimensional feature data from extracted high-dimensional feature vectors, and learn probability distribution function (PDF). All parameters of PDF are estimated by maximization the likelihood of learned expression data, and these are used to select wanted facial expressions on two-dimensional space in real time. As a result of simulation, we confirm that proposed facial expression generation tool is working in the small facial expression datasets and can generate various facial expressions without prior knowledge about relation between facial expression and emotion.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.6
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• pp.103-110
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• 2012

In Vehicle Safety Communication (VSC), noted as a representative application of VANET technologies, emergency warning messages (EWM) are broadcast over vehicles in response to an emergency situation. However, as the number of vehicles increases, the so-called Broadcast Storm Problem often occurs due to a huge number of redundant EWM transmitted. Though many approaches in the literature have been proposed to solve the problem, most of them require the preliminary phase for setting up or refreshing neighbor relationship through exchanging beacon messages with nearby vehicles, thereby further increasing the traffic load. In this paper, we propose Longest Leaping Relay (LLR) scheme which can efficiently solve the Broadcast Storm Problem without any preliminary phase for setting up neighbor relationship. Through computer simulations, we compared the performance of the proposed scheme with competitive schemes and verified the proposed scheme outperforms the existing schemes.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.584-584
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• 2015

최근 기후변화로 인한 국지성 집중호우와 태풍 등으로 홍수피해가 급증하고 있음에 따라 침수지역에 대한 공간적인 분석과 사전 예측으로 피해를 최소화하려는 노력이 필요하다. 따라서 본 연구에서는 소유역 별 평균화된 매개변수로 홍수량을 산정하는 집중형 모형이 아닌 분포형 모형을 적용하여 남강댐 유역의 유출량 산정 및 침수예측을 분석하였다. 분포형 모형은 격자체계를 기반으로 유역에 각 격자별 공간적 특성이 반영된 매개변수를 적용하므로 유역의 특성을 효과적으로 반영하므로 집중형 모형보다 정확한 해석이 가능하다. DEM, 토양도, 토지피복도 등의 격자크기 $240{\times}240$의 지형공간 자료를 ArcGIS를 이용하여 남강댐유역의 Flow direction, 경사도, 하도경사, 불투수율, 유효공극률, 조도계수, 토양심도, 수리전도도, 토양흡인수두 등의 수문매개변수를 추출하였다. 강우 자료의 경우 티센(Thiessen)법에 의해 선정된 남강댐유역 주변의 장수, 거창, 진주, 합천, 산청, 남원 강우관측소의 100년빈도 확률강우량 산정하여 24시간 확률강우를 3분위 Huff 분포시킨 후 강우의 공간적 통계특성을 반영하는 크리깅(Kriging)기법으로 적용하여 강우보간을 실시하였다. 침수예측을 위해 $Vflo^{TM}$모형을 이용해 48시간의 강우모의시간 홍수수문곡선 유도 및 홍수량 산정하였으며, 시간에 따른 침수 시뮬레이션하여 침수예측도를 작성하였다. 작성 시 침수심의 정도에 따라 5개의 구간으로 분류해 침수위험지역을 확인 할 수 있도록 도식화하였다. 본 연구에서는 남강댐유역의 침수위험지역을 개략적으로 예측할 수 있었으며, 추후 연구에서는 보다 조밀한 격자크기와 강우를 이용하여 분석한다면 향후 피난 정보 제공과 홍수재해지도 작성, 홍수방지 시설물 건설 또는 홍수보험계획 등에 응용이 될 것으로 판단된다.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.3
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• pp.86-93
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• 2011

Recently, development and application of condition monitoring and diagnostic system for improvement of durability and reliability and reduction of operating cost is generalized in the aircraft propulsion system. Expecially, for reliable operation of the high altitude and a long time and condition monitoring system to identify faults and degradations of its propulsion system should be needed. This work proposed a GUI-based On-line condition monitoring program using LabVIEW by PT6A-67 turboprop engine. The proposed on-line condition program can monitor the real engine performance as well as the trend through precise comparison between performance results calculated by the base performance simulation program and measuring engine performance signals. In the development phase of this monitoring system, a signal generation module is proposed to evaluate the proposed on-line monitoring system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.5
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• pp.47-52
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• 2021

Recently, demand for artificial intelligence solutions for production process management has been increasing in the manufacturing industry. However, through the application of AI solutions in the manufacturing industry, there are limitations to legacy smart factory solutions such as POP and MES.Therefore, in order to overcome this, this paper aims to improve production management efficiency by applying guidance, an artificial intelligence concept, to image recognition systems. In the system flow, As_is To be separated and actual work flow was applied, and the process was improved for overall productivity efficiency. The pre-processing plan for AI guidance learning was established and the relevant AI model was designed, developed, and simulated, resulting in a 97% recognition rate.

• Journal of the Korea Convergence Society
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• v.13 no.3
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• pp.55-65
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• 2022

As Internet and mobile technology is developing, the educational environment is changing from the traditional passive way into an active one driven by learners. It is important to construct the proper learner's profile for personalized education where learners are able to study according to their learning levels. The existing studies on ICT-based personalized education have mostly focused on vocabulary and learning contents. In this paper, learning profile is constructed with not only vocabulary but grammar to define a learner's learning status in more detailed way. A proficiency metric is defined which shows how a learner is accustomed to the learning contents. The simulational results present the suggested approach is effective to the evaluation essay data with each learner's proficiency that is determined after pre-learning process. Additionally, the proposed analysis technique enables to provide statistics or graphs of the learner's status and necessary data for the learner's learning contents.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.5
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• pp.725-730
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• 2022

Named Data Networking (NDN) is a representative technology of ICN that realizes the future Internet architecture. NDN searches for data by its content and not by its host IP address. The consumer generates an interest packet and sends it to the NDN network. The NDN network uses three tables such as CS, FIB, and PIT and forwards the received interest packet to the next hop. The producer transmits the data packet to the consumer through a name-based forwarding scheme. In this paper, we design and implement an ndnSIM-based NDN network and perform performance evaluation. We analyze the ndnSIM structure and develop a 6-node congested NDN network and a 9-node grid NDN network using ndnSIM. In the simulation, the performance of latency and throughput of the interest packet rate are measured. We analyze the effect of congestion on the latency and throughput of the NDN network. This approach will help researchers in the future.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.3
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• pp.117-123
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• 2022

Unlike the satellite-based outdoor positioning system, the indoor positioning system utilizes various wireless technologies such as BLE, Wi-Fi, and UWB. BLE-based beacon technology can measure the user's location by periodically broadcasting predefined device ID and location information and using RSSI from the receiving device. Existing BLE-based indoor positioning system studies have many studies comparing the error between the user's actual location and the estimated location at a single point. In this paper, we propose a technique to evaluate the positioning accuracy according to the movement path or area by applying the entropy analysis model. In addition, simulation results show that calculated entropy results for different paths can be compared to assess which path is more accurate.