• Proceedings of the Korea Information Processing Society Conference
• /
• 2010.11a
• /
• pp.1053-1056
• /
• 2010

현재 센서 네트워크 시스템을 이용한 다양한 지능형 응용들에 대한 연구가 진행되고 있다. 일반적으로 센서 네트워크는 환경정보를 수집하기 위해 많이 활용된다. 최근 더욱 상세한 환경 모니터링이나 고품질 데이터에 대한 요구로 인해 멀티미디어 데이터의 요구가 증가하고 있다. 본 논문에서는 Zigbee 기반 센서 네트워크의 낮은 대역폭의 한계를 극복하고, 실시간 멀티미디어 데이터 전송을 위한 라우팅 기법에 대한 연구를 수행한다. 기존에 제안된 멀티미디어 데이터 전송 기법의 경우 비효율적인 다중경로 설정단계로 인해 경로설정 시간의 지연이 발생하고, Zigbee 의 대역폭 한계로 인해 낮은 데이터 전송속도를 보인다. 본 논문은 기존 기법의 대역폭 문제를 해결하는 블루투스와 Zigbee 하이브리드 라우팅 구조를 제안한다. 또한 경로설정 시간 지연 문제를 해결하는 경쟁기반 비-중첩 다중 경로 설정 기법을 제안한다. 제안하는 기법의 우수성을 비교평가하기 위해 시뮬레이션을 수행하였다. 그 결과 약 78% 지연시간이 감소되었으며, 통신 속도가 약 6.9 배 증가하였다.

• Journal of KIISE:Software and Applications
• /
• v.29 no.1_2
• /
• pp.91-97
• /
• 2002

This paper describes a heuristic search technique carrying out collision avoidance for Autonomous Underwater Vehicles(AUVs). Fuzzy relational products are used as the mathematical implement for the analysis and synthesis of relations between obstacles that are met in the navigation environment and available candidate nodes. In this paper, we propose a more effective evaluation function that reflects the heuristic information of domain experts on obstacle clearance, and an advanced heuristic search method performing collision avoidance for AUVs. The search technique adopts fuzzy relational products to conduct path-planning of intelligent navigation system. In order to verify the performance of proposed heuristic search, it is compared with $A^*$ search method through simulation in view of the CPU time, the optimization of path and the amount of memory usage.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.1
• /
• pp.181-190
• /
• 2007

This paper presents a collision avoidance system for intelligent ship. Unlike collision avoidance system of other unmanned vehicles, the collision avoidance system for intelligent ship aims at not only deriving a reasonable and safe path to the goal but also keeping COLRECs(International Regulations for Preventing Collisions at Sea). The heuristic search based on the BK-products is adopted to achieve the general purpose of collision avoidance system; deriving a reasonable and safe path. The rule of action to avoid collision is adopted for the other necessary and sufficient condition; keeping the COLREGs. The verification of proposed collision avoidance system is performed with scenarios that represent encounter situations classified in the COLREGs, then it is compared with $A^{\ast}$ search method in view of optimality and safety. The analysis of simulation result revels that the proposed collision avoidance system is practical and effective candidate for real-time collision avoidance system of intelligent ship.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2002.05a
• /
• pp.140-143
• /
• 2002

본 논문에서는 자율수중운동체(AUV, Autonomous Underwater Vehicle)의 실시간 충돌회피에 적용되는 휴리스틱 탐색기법에 적합한 퍼지조건연산자와 알파절단(aleph-cut)의 선택에 관해 논한다. 퍼지조건연산자와 알파절단은 두 퍼지관계에서 새로운 퍼지관계를 생성시키는 퍼지삼각논리곱의 연산에 적용되는데 이것은 휴리스틱탐색기법의 이론적 기반이 된다. 본 논문은 평가함수를 이용한 새로운 휴리스틱탐색기법을 설계하고, 이에 가장 적합한 퍼지조건연산자와 알파절단을 제안한다. 제안된 퍼지조건연산자와 알파절단의 검증을 위해 경로경비와 합리적인 경로를 생성하는 알파절단의 개수 관점에서 모든 경우의 퍼지조건연산자와 알파절단에 대해 시뮬레이션 한다. .

• The Journal of the Korea Contents Association
• /
• v.11 no.12
• /
• pp.78-87
• /
• 2011

A variety of intelligent application using the sensor network system is being studied. In general, the sensor network consists of nodes which equipped with a variety of sensing module and is utilized to collect environment information. Recently, the demands of multimedia data are increasing due to the demands of more detailed environmental monitoring or high-quality data. In this paper, we overcome the limitations of low bandwidth in Zigbee-based sensor networks and propose a routing algorithm for real-time multimedia data transmission. In the previously proposed algorithm for multimedia data transmission occurs delay time of routing setup phase and has a low data transmission speed due to bandwidth limitations of Zigbee. In this paper, we propose the hybrid routing algorithm that consist of Zigbee and Bluetooth and solve the bandwidth problem of existing algorithm. We also propose the disjointed multipath setup algorithm based on competition that overcome delay time of routing setup phase in existing algorithm. To evaluate the superiority of the proposed algorithm, we compare it with the existing algorithm. Our experimental results show that the latency was reduced by approximately 78% and the communication speed is increased by approximately 6.9-fold.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.11
• /
• pp.141-149
• /
• 2013

IETF 6LoWPAN standard technique has been studied in IoT environment to support the IPv6 packet communication. 6LoWPAN protocol for transmission of packets mainly in the AODV routing protocol and a variety of extended techniques have been investigated. In particular, consisting of nodes with limited resources in a network error occurs when the 6LoWPAN reliable data transfer and fast routing method is needed. To this end, in this paper, we propose resilient routing protocol and extension of IETF LOAD algorithm, for optimal recovery path, More specifically, the optimal recovery path setup algorithm, signal flow, and detailed protocols for the verification of the reliability of packet transmission mathematical model is presented. The proposed protocol techniques to analyze the performance of the NS-3 performance through the simulation results that is end-to-end delay, throughput, packet delivery fraction and control packet overhead demonstrated excellence in comparison with existing LOAD.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2023.05a
• /
• pp.88-88
• /
• 2023

지난 100년 동안 전 지구의 기상 이변이 꾸준히 증가하고 있다. 기후 변화는 도시 홍수 피해에 큰 영향을 끼치는데 급속한 도시화와 이상 기후로 인한 돌발 강우 패턴의 증가는 도시 침수의 취약성을 가중시킨다. 또한 급격한 도시 발전으로 인한 도심지의 불투수율 또한 꾸준히 증가하였다. 특히 2022년 8월 8일에 강남역과 도림천 일대에 내린 기록적인 강우는 기후 변화를 실감하게 하는 사회적 이슈가 되었으며 도심지 미래 수방 대책 변화를 상기시키는 계기가 되었다. 이로 인한 재해 피해에 최소화하기 위해 미래 기후 변화를 고려한 도심지의 새로운 방재 목표강우량 설정이 필요하다. 하지만 전 지구 모형(GCM)의 기후 변화 시나리오는 일 단위(Daily) 상세화 자료를 보편적으로 사용하고 있다. 하지만 이는 단기 강우 자료를 필요로 하는 도시 홍수 모의에서 제대로 활용할 수 없는 한계를 가지고 있다. 따라서 본 연구는 2019년에 발간된 IPCC 6차 평가 보고서(AR6)가 제안하는 SSP(Shared Socioeconomic Pathways, 공통사회경제경로) 시나리오를 기반하여 상세화된 일 단위(Daily) 강우 데이터를 비모수적 통계 기법을 사용하여 시간 단위(Hourly)로 상세화하였다. 또한 지속 시간별 연 최대치 강우를 추출하여 빈도 해석을 통해 도시 유역의 미래 확률 강우량을 제시하였으며, 서울시 상습적인 침수 취약 지역인 도림천 유역에 강우-유출 모형(XP-SWMM)을 사용하여 미래전망 기후 자료인 SSP2-4.5와 SSP5-8.5에 따른 미래 확률 강우 침수 모의를 실시하였다. 본 연구의 결과는 최신 기후 변화 시나리오를 고려한 서울시 방재 성능 목표 강우량 산정에 활용 가능할 것으로 사료되며 미래 강우량 침수 모의를 통해 침수 취약 구역인 도림천 일대 홍수피해의 근거 자료가 되는 것에 의의를 둔다. 또한 치수 분야에서 기후 변화를 고려하기 위해서는 기후 변화 시나리오에 따른 시간 단위 자료의 상세화가 필요함을 시사한다.

• The Journal of Bigdata
• /
• v.8 no.2
• /
• pp.1-13
• /
• 2023

Current analysis of air passengers mainly relies on statistical methods, but there are limitations in analyzing detailed aspects such as travel routes, number of regional passengers and airport access times. However, with the advancement of big data technology and revised three data acts, big data-based transportation analysis has become more active. Mobile communication data, which can precisely track the location of mobile phone terminals, can serve as valuable analytical data for transportation analysis. In this paper, we propose a air passenger Origin/Destination (O/D) extraction algorithm based on mobile communication data that overcomes the limitations of existing air transportation user analysis methods. The algorithm involves setting airport signal detection zones at each airport and extracting air passenger based on their base station connection history within these zones. By analyzing the base station connection data along the passenger's origin-destination paths, we estimate the entire travel route. For this paper, we extracted O/D information for both domestic and international air passengers at all domestic airports from January 2019 to December 2020. To compensate for errors caused by mobile communication service provider market shares, we applied a adjustment to correct the travel volume at a nationwide citizen level. Furthermore correlation analysis was performed on O/D data and aviation statistics data for air traffic users based on mobile communication data to verify the extracted data. Through this, there is a difference in the total amount (4.1 for domestic and 4.6 for international), but the correlation is high at 0.99, which is judged to be useful. The proposed algorithm in this paper enables a comprehensive and detailed analysis of air transportation users' travel behavior, regional/age group ratios, and can be utilized in various fields such as formulating airport-related policies and conducting regional market analysis.

• The KIPS Transactions:PartA
• /
• v.11A no.4
• /
• pp.277-284
• /
• 2004

This paper presents a facial expression control method of 3D avatar that enables the user to select a sequence of facial frames from the facial expression space, whose level of details the user can select hierarchically. Our system creates the facial expression spare from about 2,400 captured facial frames. But because there are too many facial expressions to select from, the user faces difficulty in navigating the space. So, we visualize the space hierarchically. To partition the space into a hierarchy of subspaces, we use fuzzy clustering. In the beginning, the system creates about 11 clusters from the space of 2,400 facial expressions. The cluster centers are displayed on 2D screen and are used as candidate key frames for key frame animation. When the user zooms in (zoom is discrete), it means that the user wants to see mort details. So, the system creates more clusters for the new level of zoom-in. Every time the level of zoom-in increases, the system doubles the number of clusters. The user selects new key frames along the navigation path of the previous level. At the maximum zoom-in, the user completes facial expression control specification. At the maximum, the user can go back to previous level by zooming out, and update the navigation path. We let users use the system to control facial expression of 3D avatar, and evaluate the system based on the results.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.19 no.2
• /
• pp.1-13
• /
• 2016

In an effort to establish adaptive measures for low carbon use and climate change, this study developed storylines for shared socio-economic reference pathways(SSP) and simulated change in land use for each storyline. First, cellular automata modeling was performed using past data, and a transition rule for the local characteristics of each planning area under study was derived by comparing with the results of the base year. Second, three storylines were formulated based on the hypothesized change in land use for the SSP. SSP1, the scenario for sustainability, assumed that the land was developed into a compact city, SSP2 assumed the development of a road through the middle of the land while maintaining the current situation, and SSP3 assumed unsustainable development into a fragmented world. Third, change in land use depending on planning area was predicted by integrating the SSP scenarios with cellular automata(CA) modeling. According to the results of analysis using the SSP scenarios, the urban area ratio increased slightly up to 2020 in SSP1 and up to 2030 in SSP2 and did not change any more subsequently, but it increased continuously until 2050 in SSP3 that assumed low level urban planning. These results on change in land use are expected to contribute towards making reasonable decisions and policies on climate change, and the outcomes of simulation derived from spatial downscaling, if applied to vulnerability assessment, will be useful to set the priority of policies on climate change adaptation.