• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2002년도 ITC-CSCC -3
• /
• pp.1859-1862
• /
• 2002

The replication of data is used to increase its availability, improve the performance of a system, and advance the fault-tolerance of a system. In this paper, it is required for the information about the location of a primary site of the replicas of each data item. The replicas of each data item are hierarchically organized to a tree based on the fact that the root is the primary replica in partially replicated databases. It eliminates useless propagation since the propagation can be done to only sites having replicas following the hierarchy of data. And our algorithm schedules transactions so that the execution order of updates at each primary site is identical at all sites by using timestamp. Using our algorithm, the consistent data are supplied and the performance of read-only transactions can be improved by using tree structure of replicas of each data item.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.36.5-36
• /
• 2001

Localization is one of the key problems in the navigation of autonomous mobile robots. The probabilistic Markov localization approaches offer a good mathematical framework to deal with the uncertainty of environment and sensor readings but their use for realtime applications is limited by their computational complexity. This paper aims to reduce the high computational cost associated with the probabilistic Markov localization algorithm. We propose a hybrid landmark-based localization method combining triangulation and probabilistic approaches, which can efficiently update position probability grid, while the probabilistic framework allows to make use of any available sensor data to refine robot´s belief about its current location. The simulation results show the effectiveness and robustness of the method.

• Interaction and multiscale mechanics
• /
• 제4권1호
• /
• pp.49-64
• /
• 2011

A methodology for jointed rock mass characterization starts with a research based on geological data and tests in order to define the geotechnical models used to support the decision about location, orientation and shape of cavities. Afterwards a more detailed characterization of the rock mass is performed allowing the update of the geomechanical parameters defined in the previous stage. The observed results can be also used to re-evaluate the geotechnical model using inverse methodologies. Cases of large underground structures modeling are presented. The first case concerns the modeling of cavities in volcanic formations. Then, an application to a large station from the Metro do Porto project developed in heterogeneous granite formations is also presented. Finally, the last case concerns the modeling of large cavities for a hydroelectric powerhouse complex. The finite element method and finite difference method software used is acquired from Rocscience and ITASCA, respectively.

• 한국컴퓨터정보학회논문지
• /
• 제11권4호
• /
• pp.261-269
• /
• 2006

본 논문에서는 임베디드 리눅스를 이용하여 위치기반 관광정보안내 단말기를 설계 및 구현하였다. 구현 된 단말기는 GPS 인터페이스를 통해 단말의 현재 위치를 파악하고 해당 관광지의 정보를 Qt-embedded 윈도우상에서 디스플레이한다. 논문의 단말기는 타겟보드상에서 부트로더와 임베디드 리눅스 커널 및 각종디바이스 드라이버가 구현되었으며 GUI로는 임베디드 윈도 매니저인 Qtopia를 이용하여 애플리케이션을 개발하였다. 구현 결과 무료 운영체제를 이용한 모바일 관광안내 단말기로서 기능을 충분히 수행할 수 있음을 확인하였고, 향후 연구과제로는 통신 기능을 추가하여 단말기의 관광 정보를 실시간에 업데이트 할 수 있는 기능을 구현하는 것이다.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2004년도 춘계학술발표대회
• /
• pp.1417-1420
• /
• 2004

The combination of Fast-Handoff and Hierarchical Mobile IPv6 (F-HMIPv6) allows the anticipation of the layer3 handoff such that data traffic can be efficiently redirected to the mobile node's new location before it moves there. However, after moving to the new Access Router (NAR), if the mobile node (MN) sends the Local Binding Update (LBU) to the Mobility Anchor Point (MAP) before receiving all of the buffered packet from the NAR, the MN may receive the general packet from the MAP. That is, the MN may simultaneously receive two types of packet which has different sequence number. These cause the confusion in packet order, and the MN sends the dup ack for the packet retransmission to the CN. It results in the degradation of the TCP performance. Therefore, we propose the scheme for minimizing the out-of-sequence packet in F-HMIPv6.

• International journal of advanced smart convergence
• /
• 제12권4호
• /
• pp.35-43
• /
• 2023

This paper emphasizes that information received in disaster situations can lead to disparities in the effectiveness of communication, potentially causing damage. As a result, there is a growing demand for disaster and safety information among citizens. A user-centered disaster and safety information application service is designed to address the rapid dissemination of disaster and safety-related information, bridge information gaps, and alleviate anxiety. Through the Open API (Open Application Programming Interface), we can obtain clear information about the weather, air quality, and guidelines for disaster-related actions. Using chatbots, we can provide users with information and support decision-making based on their queries and choices, utilizing cloud APIs, public data portal open APIs, and solution knowledge bases. Additionally, through Mashup techniques with the Google Maps API and Twitter API, we can extract various disaster-related information, such as the time and location of disaster occurrences, update this information in the disaster database, and share it with users.

• Structural Engineering and Mechanics
• /
• 제91권6호
• /
• pp.591-606
• /
• 2024

This article proposes a new methodology for identifying beam damage based on changes in modal parameters using the Double Stage Extended Improved Particle Swarm Optimization (DSEIPSO) technique. A finite element code is first developed in MATLAB to model an ideal beam structure based on classical beam theory. An experimental study is then performed on a laboratory-scale beam, and the modal parameters are extracted. An improved version of the PSO algorithm is employed to update the finite element model based on the experimental measurements, representing the real structure and forming the baseline model for all further damage detection. Subsequently, structural damages are introduced in the experimental beam. The DSEIPSO algorithm is then utilized to optimize the objective function, formulated using the obtained mode shapes and the natural frequencies from the damaged and undamaged beams to identify the exact location and extent of the damage. Experimentally obtained resultsfrom a simple cantilever beam are used to validate the effectiveness of the proposed method. The illustrated results show the effectiveness of the proposed method for structural damage detection in the SHM field.

• 한국융합학회논문지
• /
• 제11권10호
• /
• pp.97-106
• /
• 2020

산업입지정보시스템에서 제공하는 공장정보는 한국산업단지공단으로부터 원시데이터를 받아 필터링 과정을 거친 후 등록되기 때문에 새로운 공장 정보 갱신이 느린 특징이 있다. 본 연구에서는 산업입지정보시스템 공장 정보 갱신 문제를 해결하고자, 비교적 갱신 주기가 빠른 도로명 주소의 건물 데이터와 부동산의 건물 데이터를 이용하여 기존의 산업입지정보시스템 공장정보와 비교하고 새로운 공장정보를 추출하였다. 속성정보 매칭을 수행하고, 속성정보의 누락으로 매칭할 수 없는 공장의 경우에는 공간객체 매칭을 수행하였다. 위 과정에서 점 데이터와 다각형 데이터와 같이 형식이 다른 공간객체를 비교하는 방안을 제시하였다. 제안된 공간분석 방법의 정확도 평가 결과 약 79%의 정확도를 보였으며, 위 매칭 기법을 활용하여 도로명주소건물데이터, 부동산건물데이터와 산업입지정보시스템 공장정보의 융합 가능성을 확인하였다.

• 사물인터넷융복합논문지
• /
• 제2권2호
• /
• pp.21-26
• /
• 2016

본 논문에서는 지역 상권들과의 연계가 가능하며 실시간 관광정보 업데이트 및 무선 데이터망 없이도 관광정보를 제공할 수 있는 블루투스 비콘기반의 온오프라인 관광 솔루션(BBTS)을 제안한다. BBTS는 블루투스 기반의 저전력 데이터 공급시스템과 비콘과 연동 가능한 스마트 어플리케이션으로 구성되어 있다. 데이터 공급시스템은 브류투스 비콘 기반의 Pairing/non-pairing 데이터 전송모듈과 일체형 하드웨어로 되어있다. 스마트 어플리케이션은 설치된 비콘 중심으로 사용자의 실내위치정보를 제공하는 모듈, 주변정보(교통, 숙박 쇼핑, 관광지 등)를 제공하는 기능 그리고 관광지 정보수집 서버구축과 내부 가이드 어플리케이션으로 구성되어 있다. BBTS는 Beacon 기술을 활용하기 때문에 관광객이 요구하는 실내 관광서비스가 가능하며 실외관광 정보는 비콘에서 수신 받는 정보를 APK 파일로 스마트폰에 다운받아 서비스를 제공받을 수 있도록 개발되어 스마트관광 서비스 산업에 큰 파급효과를 불러일으킬 수 있을 것으로 기대된다.

• 국제학술발표논문집
• /
• The 8th International Conference on Construction Engineering and Project Management
• /
• pp.510-519
• /
• 2020

Within an intelligent automated cyber-physical system, the realization of the autonomous mechanism for data collection, data integration, and data analysis plays a critical role in the design, development, operation, and maintenance of such a system. This construct is particularly vital for fault-tolerant route-finding systems that rely on the imprecise GPS location of the vehicles to properly operate, timely plan, and continuously produce informative feedback to the user. More essentially, the integration of digital twins with cyber-physical route-finding systems has been overlooked in intelligent transportation services with the capacity to construct the network routes solely from the locations of the operating vehicles. To address this limitation, the present study proposes a conceptual architecture that employs digital twin to autonomously maintain, update, and manage intelligent transportation systems. This virtual management simulation can improve the accuracy of time-of-arrival prediction based on auto-generated routes on which the vehicle's real-time location is mapped. To that end, first, an intelligent transportation system was developed based on two primary mechanisms: 1) an automated route finding process in which predictive data-driven models (i.e., regularized least-squares regression) can elicit the geometry and direction of the routes of the transportation network from the cloud of geotagged data points of the operating vehicles and 2) an intelligent mapping process capable of accurately locating the vehicles on the map whereby their arrival times to any point on the route can be estimated. Afterward, the digital representations of the physical entities (i.e., vehicles and routes) were simulated based on the auto-generated routes and the vehicles' locations in near-real-time. Finally, the feasibility and usability of the presented conceptual framework were evaluated through the comparison between the primary characteristics of the physical entities with their digital representations. The proposed architecture can be used by the vehicle-tracking applications dependent on geotagged data for digital mapping and location tracking of vehicles under a systematic comparison and simulation cyber-physical system.