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Dynamic Service Composition and Development Using Heterogeneous IoT Systems
Minwoo Ryu(류민우),Jaeseok Yun(윤재석) 한국컴퓨터정보학회 2017 韓國컴퓨터情報學會論文誌 Vol.22 No.9
IoT (Internet of Things) systems are based on heterogeneous hardware systems of different types of devices interconnected each other, ranging from miniaturized and low-power wireless sensor node to cloud servers. These IoT systems composed of heterogeneous hardware utilize data sets collected from a particular set of sensors or control designated actuators when needed using open APIs created through abstraction of devices’ resources associated to service applications. However, previously existing IoT services have been usually developed based on vertical platforms, whose sharing and exchange of data is limited within each industry domain, for example, healthcare. Such problem is called ‘data silo’, and considered one of crucial issues to be solved for the success of establishing IoT ecosystems. Also, IoT services may need to dynamically organize their services according to the change of status of connected devices due to their mobility and dynamic network connectivity. We propose a way of dynamically composing IoT services under the concept of WoT (Web of Things) where heterogeneous devices across different industries are fully integrated into the Web. Our approach allows developers to create IoT services or mash them up in an efficient way using Web objects registered into multiple standardized horizontal IoT platforms where their resources are discoverable and accessible. A Web-based service composition tool is developed to evaluate the practical feasibility of our approach under real-world service development.
건축물 실내의 포인트 클라우드 데이터 기반의 자연재해 피해 분석에 관한 기초연구
류민우(Ryu, Minwoo),오상민(Oh, Sangmin),이찬우(Lee, Chanwoo),오병준(Oh, Byungjun),조훈희(Cho, Hunhee),강경인(Kang, Kyung-In) 대한건축학회 2019 대한건축학회 학술발표대회 논문집 Vol.39 No.2
In this Study, we obtain the 3d geometric representation and calculate the structural deformation of buildings to propose the data for quantitative estimation of disaster damage based on the point cloud data(PCD). First, we compose the geometric plane of each structural composite using Random Sample Consensus(RANSAC) method and PCD which is obtained by Handheld Laser Scanner. Second, we obtain the geometric representation and calculate the structural deformation of each composite based on the geometric planes. Last, we analyze the deformation to propose the quantitative standard for damage caused by natural disaster The result of this study can be utilized as fundamental data for accurate estimation of disaster damage on buildings.
서비스 오케스트레이션 기반 사용자 맞춤형 IoT 서비스의 설계 및 구현
차시호,류민우,Cha, Siho,Ryu, Minwoo 디지털산업정보학회 2015 디지털산업정보학회논문지 Vol.11 No.3
The Internet of Things (IoT) is an Infrastructure which allows to connect with each device in physical world through the Internet. Thus IoT enables to provide meahup services or intelligent services to human user using collected data from those devices. Due to these advantages, IoT is used in divers service domains such as traffic, distribution, healthcare, and smart city. However, current IoT provides restricted services because it only supports monitor and control devices according to collected data from the devices. To resolve this problem, we propose a design and implementation of personalized IoT service base on service orchestration. The proposed service allows to discover specific services and then to combine the services according to a user location. To this end, we develop a service ontology to interpret user information according to meanings and smartphone web app to use the IoT service by human user. We also develop a service platform to work with external IoT platform. Finally, to show feasibility, we evaluate the proposed system via study.
차량의 이동 방향과 거리 기반의 그리디 애니캐스트 포워딩 프로토콜
차시호,이종언,류민우,Cha, Siho,Lee, Jongeon,Ryu, Minwoo 디지털산업정보학회 2017 디지털산업정보학회논문지 Vol.13 No.1
Vehicular ad-hoc networks (VANETs) cause link disconnection problems due to the rapid speed and the frequent moving direction change of vehicles. Link disconnection in vehicle-to-vehicle communication is an important issue that must be solved because it decreases the reliability of packet forwarding. From the characteristics of VANETs, greedy forwarding protocols using the position information based on the inter-vehicle distance have gained attention. However, greedy forwarding protocols do not perform well in the urban environment where the direction of the vehicle changes greatly. It is because greedy forwarding protocols select the neighbor vehicle that is closest to the destination vehicle as the next transmission vehicle. In this paper, we propose a greedy anycast forwarding (GAF) protocol to improve the reliability of the inter-vehicle communication. The proposed GAF protocol combines the greedy forwarding scheme and the anycast forwarding method. Simulation results show that the GAF protocol can provide a better packet delivery rate than existing greedy forwarding protocols.
IoT에서 효율적인 서비스 제공을 위한 이름 기반 서비스 탐색 메커니즘
조국현(Kuk-Hyun Cho),김정재(Jung-Jae Kim),류민우(Minwoo Ryu),차시호(Si-Ho Cha) 한국산학기술학회 2018 한국산학기술학회논문지 Vol.19 No.6
IoT는 다양한 디바이스들이 통신을 통해 사용자에게 서비스를 제공하는 환경이다. IoT의 특성으로 인해 데이터들은 이종간의 정보시스템에 분산되어 저장된다. 이러한 상황에서 IoT 엔드 애플리케이션은 데이터가 어디에 있는지 또는 스토리지의 형태가 어떠한지 알 수 없어도 데이터를 액세스할 수 있어야 한다. 이러한 메커니즘을 SD(Service Discovery)라고 한다. 그러나 현재까지의 SD 구조는 물리적 디바이스를 중심으로 탐색하기 때문에 몇 가지 문제점이 발생한다. 첫째, 물리적 위치에 따른 서비스 탐색으로 인해 반환시간이 증대된다. 둘째, 디바이스와 서비스를 따로 관리하는 데이터 구조가 요구된다. 이는 관리자의 서비스 구성복잡도를 증가시킨다. 이로 인해 디바이스 중심의 SD 구조는 실제 IoT에 적용하기에는 적합하지 않은 구조로 되어 있다. 이러한 문제점을 해결하기 위하여 본 논문에서는 NSSD(Name-based Service Centric Service Discovery)라는 SD 구조를 제안한다. NSSD는 이름 기반의 중앙집중형 SD를 제공하며 IoT 에지 게이트웨이를 캐싱 서버로 사용해 서비스 탐색속도를 향상시킨다. 기존의 DNS와 DHT 기반 DS 구조와의 시뮬레이션을 통해 NSSD가 평균 반환시간에 있어 약 2배 정도 향상된 성능을 제공함을 입증하였다. The Internet of Things (IoT) is an environment in which various devices provide services to users through communications. Because of the nature of the IoT, data are stored and distributed in heterogeneous information systems. In this situation, IoT end applications should be able to access data without having information on where the data are or what the type of storage is. This mechanism is called Service Discovery (SD). However, some problems arise, since the current SD architectures search for data in physical devices. First, turnaround time increases from searching for services based on physical location. Second, there is a need for a data structure to manage devices and services separately. These increase the administrator"s service configuration complexity. As a result, the device-oriented SD structure is not suitable to the IoT. Therefore, we propose an SD structure called Name-based Service-centric Service Discovery (NSSD). NSSD provides name-based centralized SD and uses the IoT edge gateway as a cache server to speed up service discovery. Simulation results show that NSSD provides about twice the improvement in average turnaround time, compared to existing domain name system and distributed hash table SD architectures.