• 제어로봇시스템학회논문지
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• 제17권7호
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• pp.651-658
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• 2011

An efficient modified $D^*$ lite algorithm is suggested, which can perform online path planning for mobile robots in dynamic indoor environment. Online path planning should plan and execute alternately in a short time, and hence it enables the robot avoid unknown dynamic obstacles which suddenly appear on robot's path. Based on $D^*$ Lite algorithm, we improved representation of edge cost, heuristic function, and priority queue management, to build a modified $D^*$ Lite algorithm. Performance of the proposed algorithm is revealed via extensive simulation study.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.471-474
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• 2004

In this paper, a NURBS surface interpolator is proposed which can deal with shapes defined from CAD/CAM programs on a surface basis and can improve contour accuracy. The proposed interpolator is based on newly defined G-codes and includes online tool-path planning suitable for NURBS surface machining. The real-time interpolation algorithm, considering an effective machining method for each machining process and minimum machining time, is executed in an online manner. The proposed interpolator is implemented on a PC-based 3-axis CNC milling system and evaluated through actual machining in terms of machining time and regulation of feedrate and cutting force in comparison with the existing method.

• 제어로봇시스템학회논문지
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• 제22권3호
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• pp.192-198
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• 2016

Motion planning problem is still one of the important issues in robotic applications. In many real-time motion planning problems, it is advisable to find a feasible solution quickly and improve the found solution toward the optimal one before the previously-arranged motion plan ends. For such reasons, sampling-based approaches are becoming popular for real-time application. Especially the use of a rapidly exploring random $tree^*$ ($RRT^*$) algorithm is attractive in real-time application, because it is possible to approach an optimal solution by iterating itself. This paper presents a modified version of informed $RRT^*$ which is an extended version of $RRT^*$ to increase the rate of convergence to optimal solution by improving the sampling method of $RRT^*$. In online motion planning, the robot plans a path while simultaneously moving along the planned path. Therefore, the part of the path near the robot is less likely to be sampled extensively. For a better solution in online motion planning, we modified the sampling method of informed $RRT^*$ by combining with the sampling method to improve the path nearby robot. With comparison among basic $RRT^*$, informed $RRT^*$ and the proposed $RRT^*$ in online motion planning, the proposed $RRT^*$ showed the best result by representing the closest solution to optimum.

• 한국정밀공학회지
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• 제23권9호
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• pp.156-163
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• 2006

The purpose of this study is to improve the machining of free-formed NURBS surfaces using newly defined G-codes which can directly deal with shapes defined from CAD/CAM programs on a surface basis and specialize in rough and finish cut. To this purpose, a NURBS surface interpolation system is proposed in this paper. The proposed interpolation system includes online tool-path planning, real-time interpolation and feedrate regulation considering an effective machining method and minimum machining time all suitable for unit NURBS surface machining. The corresponding algorithms are simultaneously executed in an online manner. The proposed NURBS surface interpolation system is integrated and implemented with a PC-based 3-axis CNC milling system. A graphic user interface (GUI) and a 3D tool-path viewer which interprets the G-codes for NURBS surfaces and displays whole tool-paths are also developed and included in our real-time control system. The proposed system is evaluated through actual machining in terms of size of NC data, machining time, regulation of feedrate and cutting force focused on finish cut in comparison with the existing method.

• 한국산업융합학회 논문집
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• 제19권2호
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• pp.75-80
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• 2016

This study proposes a efficient technology to control the optimal trajectory planning and real-time implementation method which can perform autonomous travelling for unmaned factory automation. Online path planning should plan and execute alternately in a short time, and hence it enables the robot avoid unknown dynamic obstacles which suddenly appear on robot's path. Based on Route planning and control algorithm, we suggested representation of edge cost, heuristic function, and priority queue management, to make a modified Route planning algorithm. Performance of the proposed algorithm is verified by simulation test.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권12호
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• pp.3197-3218
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• 2012

Compared with traditional itinerary planning, intention-oriented itinerary recommendations can provide more flexible activity planning without requiring the user's predetermined destinations and is especially helpful for those in unfamiliar environments. The rank and classification of points of interest (POI) from location-based social networks (LBSN) are used to indicate different user intentions. The mining of vehicles' physical trajectories can provide exact civil traffic information for path planning. This paper proposes a POI category-based itinerary recommendation framework combining physical trajectories with LBSN. Specifically, a Voronoi graph-based GPS trajectory analysis method is utilized to build traffic information networks, and an ant colony algorithm for multi-object optimization is implemented to locate the most appropriate itineraries. We conduct experiments on datasets from the Foursquare and GeoLife projects. A test of users' satisfaction with the recommended items is also performed. Our results show that the satisfaction level reaches an average of 80%.

• 유통과학연구
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• 제18권6호
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• pp.25-35
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• 2020

Purpose:Travel agencies have use digital tools in order to shift the paradigm in how business is conducted. Online travel agencies provide the same services as a normal travel agency, including hotels, transportation, guided tours, reservations, and related services, but using an "online platform. Travelers planning a trip can use a lot of forms to collect information and have access to a larger amount of information, so the factors that influence the user's behavioral intention are very important. This research has the conducted to find what factors lead to the attitudes of consumers in using OTA using the UTAUT model. Research design, data and methodology: The object of this study were respondents of a google survey using convenient sample extraction method, chosen among consumers who gathered information, or purchased a product. A total of 217 of the 235 questionnaires Google survey answered were used in the final analysis, excluding insincere responses. Using PSS v.21 and AMOS v.21, frequency analysis, feasibility and reliability analysis, path analysis was performed. Results: UTAUT affects OTA use satisfaction and trust, and OTA satisfaction and trust affect behavior intention. Conclusions: Research was conducted using the UTAUT model to explore factors that affect the attitudes of users of online travel agencies (OTA).

• 한국융합학회논문지
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• 제10권7호
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• pp.23-31
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• 2019

2016년 한국에 미군의 사드 미사일이 배치된 이후 중국으로부터 단체관광은 전면 중단되었다. 이후 중국인의 한국 관광은 개인 중심의 여행일정으로 이루어지고 있다. 본 연구에서는 2018년 1월부터 12월 까지 온라인 여행노트를 통해 데이터를 수집하고, 소셜 네트워크 분석을 활용하여 개별방문 중국인의 계절별 한국관광 여정 특성을 분석하였다. 분석 결과 서울은 중국인의 한국여행 허브이며 개별 방문 중국인의 주요 방문지는 서울, 부산, 제주도, 경주 및 강릉에 집중되어 있고 계절에 따라 큰 차이가 있는 것으로 나타났다. 연구 결과는 개별 중국인의 한국 관광을 위한 관광코스의 개발, 관광 서비스 제공 및 관광 시설배치의 최적화를 위한 기초자료로 활용될 수 있다. 향후 연구는 여행 방문지와 관광명소 사이의 이동 교통방식을 연구하여 관광 일정 계획 설계에 참고를 제공할 수 있다.

• ETRI Journal
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• 제43권4호
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• pp.617-629
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• 2021

Although the actual visual simultaneous localization and mapping (SLAM) algorithms provide highly accurate tracking and mapping, most algorithms are too heavy to run live on embedded devices. In addition, the maps they produce are often unsuitable for path planning. To mitigate these issues, we propose a completely closed-loop online dense RGB-D SLAM algorithm targeting autonomous indoor mobile robot navigation tasks. The proposed algorithm runs live on an NVIDIA Jetson board embedded on a two-wheel differential-drive robot. It exhibits lightweight three-dimensional mapping, room-scale consistency, accurate pose tracking, and robustness to moving objects. Further, we introduce a navigation strategy based on the proposed algorithm. Experimental results demonstrate the robustness of the proposed SLAM algorithm, its computational efficiency, and its benefits for on-the-fly navigation while mapping.

• 문화기술의 융합
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• 제6권1호
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• pp.343-350
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• 2020

본 논문에서는 고고역사 공간정보 공유 플랫폼인 '실크로드피아(Silkroadpia)'의 개발과 고대 경로 및 영역권 복원 알고리듬(MEPTA)의 제작·실행을 통해 전라북도 지역을 통과한 고대 문명교류의 경로들을 복원하고자 한 연구의 결과물을 제시하였다. 이 작업을 통해 전라북도 지역의 역사적 정체성 및 한반도와 동아시아에서의 위상을 재조명하였고, 정부의 국토공간정책을 지원할 수 있는 이론적 근거 및 지역재생을 위한 적절한 문화컨텐츠를 제시하였다. 본 논문에서 필자는 고고학, 역사학, 지리학, 공학 분야의 융합연구에 기반한 고대 경로 복원의 대표적인 사례로서 기원후 660년 사비성 함락 이후 진행된 백제부흥운동의 길을 제시하였다. 즉 본 논문에서는 동진강하구를 백강으로, 부안 우금산성을 주류성으로 각각 상정하였으며, MEPTA를 이용하여 당시 왜군의 이동경로인 동진강입구에서 우금산성까지의 길을 추정하였다. 다음으로 백제부흥군이 우금산성에서 김제 성산성(피성)으로 본영을 옮긴 경로를 추정하고 그 가능성을 타진하였다. 마지막으로 본 논문에서는 이러한 경로추정 알고리듬의 적용을 통하여 새롭게 확보된 고대 문명교류의 길을 활용하여 스토리텔링, 관광상품 개발, 공간 조성 등 다양한 활용 방안을 모색할 수 있음을 밝혔다.