• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.3
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• pp.24-33
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• 2009

Stream data, gathered from ubiquitous sensor networks, change continuously over time. Because they have quite different characteristics from traditional databases, we need new techniques for storing and querying/analyzing these stream data, which are research issues recently emerging. In this research, we implemented a storage manager gathering stream data and storing them into databases, which are sampled continuously from sensor networks. The storage manager cleans faulty data occurred in mobile sensors and it also reduces the size of stream data by merging repeatedly-sampled values into one and by employing the tilted time frame which stores stream data with several different sampling rates. In this research furthermore, we measured the performance of the storage manager in the context of a sensor network monitoring fires of a building. The experimental results reveal that the storage manager reduces significantly the size of storage spaces and it is effective to manage the data stream for real applications monitoring buildings and their fires.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.6
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• pp.125-134
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• 2009

Ubiquitous are not courted in time and place of users and must offer service in network freely. There is telematics by representative application service during it. telematics service must provide service that is personalized according to time and place. Also, user who use telematics service must offer service that can use automatically even if do not request service. Therefore, in the paper wish to embody service discovery way design in telematics environment because treatise that see uses UPnP through PDA that is user Mobile terminal. PDA connected by local server of telematics service point and Bluetooth communication, and use finding UPnP device and service that is linked with local server using UPnP. Design UPnP device that provide service to user in telematics environment. Construct telematics service test bed to test service discovery. Because constructed system applies UPnP on Bluetooth communication base, service discovery system implementation and test.

• Journal of Advanced Navigation Technology
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• v.23 no.2
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• pp.194-199
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• 2019

Natural disasters destroy decades of human effort and investments, thereby placing new demands on society for reconstruction and rehabilitation. In most case, the natural phenomena triggering the disasters are beyond human control. In order to solve the problems that the information resources can not be shared among disaster management sectors and their work is hard to be coordinated in city, an idea of application of ubiquitous sense network and ICT technology to model the architecture of the disaster prevention system based on the analysis of characteristics of disasters. The proposed algorithm simulated that it is possible to locate the terminal by linking the direction angle and the estimated position that can be confirmed at the time of stopping, even if the movement direction of the terminal does not move in a certain direction with only a smaller number of mobile base stations. We also confirmed that the proposed algorithms analyzed through simulation are more efficient than existing algorithms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.10
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• pp.1469-1476
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• 2022

Recently, many researches have been conducted to estimate blood pressure using ECG(Electrocardiogram) and PPG(Photoplentysmography) signals. In this paper, we designed and implemented a mobile system to monitor blood pressure in real time by using 1-D convolutional neural networks. The proposed model consists of deep 11 layers which can learn to extract various features of ECG and PPG signals. The simulation results show that the more the number of convolutional kernels the learned neural network has, the more detailed characteristics of ECG and PPG signals resulted in better performance with reduced mean square error compared to linear regression model. With receiving measurement signals from wearable ECG and PPG sensor devices attached to the body, the developed system receives measurement data transmitted through Bluetooth communication from the devices, estimates systolic and diastolic blood pressure values using a learned model and displays its graph in real time.

• Journal of the Korea Convergence Society
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• v.7 no.6
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• pp.49-54
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• 2016

The IoT has attracted attention as one of the technologies that are applied to various industries and create new services. The IoT can utilize existing network technologies to create services by providing Internet connection between objects. Objects Personalized services can be created by collecting various data using the IoT. In the field of agriculture, we are promoting sustainable agriculture and enhancing competitiveness through the use of the IoT, and the convergence of IoT in agriculture is pushing for smart agriculture. In Korea, the Ministry of Agriculture, Food and Rural Affairs is preparing measures to spread smart farms to improve agricultural competitiveness using IoT technology. Therefore, we propose the development model of smart agriculture in the future through the case study on the IoT based on agriculture.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.1
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• pp.72-76
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• 2009

Recently, as the interest of ubiquitous computing has been increased there has been lots of research about recognizing human activities to provide services in this environment. Especially, in mobile environment, contrary to the conventional vision based recognition researches, lots of researches are sensor based recognition. In this paper we propose to recognize the user's activity with multi-modal sensors using hierarchical dynamic Bayesian networks. Dynamic Bayesian networks are trained by the OVR(One-Versus-Rest) strategy. The inferring part of this network uses less calculation cost by selecting the activity with the higher percentage of the result of a simpler Bayesian network. For the experiment, we used an accelerometer and a physiological sensor recognizing eight kinds of activities, and as a result of the experiment we gain 97.4% of accuracy recognizing the user's activity.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.3
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• pp.134-148
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• 2007

There is not enough knowledge on how to use, build, and apply ubiquitous technologies such as the ubiquitous sensor network, GIS, statistic analysis system, mobile GPS system etc. Also there are other questions such as, how should the knowledge information resources be managed and web decision making system developed for national park management. The purpose of this study is to propose a framework for the national park integrated management system based on ubiquitous information technology. This study will include followings: 1) this study explores what ubiquitous information technologies are needed for national park management, 2) this study proposes building strategies about the spatial and attribute database using ubiquitous information technologies, and links methods among geographic information system, analysis program, sensor network, etc. The results of this study will contribute towards deciding a direction for national park policy in preparation for the ubiquitous computing oriented society.

• Journal of IKEEE
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• v.18 no.1
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• pp.57-63
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• 2014

This paper is to technically implement the sensing platform for Home-Wellness Robot. The self-Localization of indoor mobile robot is very important for the sophisticated trajectory control. In this paper, the robot's self-localization algorithm is designed by RF sensor network and fuzzy inference. The robot realizes its self-localization, using RFID sensors, through the collaboration algorithm which uses fuzzy inference for combining the strengths of triangulation and triangulation. For the triangulation self-Localization, RSSI is implemented. TOA method is used for realizing the triangulation self-localization. The final improved position is, through fuzzy inference, made by the fusion algorithm of the resultant coordinates from trilateration and triangulation in real time. In this paper, good performance of the proposed self-localization algorithm is confirmed through the results of a variety of experiments in the base of RFID sensor network and reader system.

• Journal of Digital Convergence
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• v.13 no.2
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• pp.291-297
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• 2015

The basic idea of IoT(Internet of Things) is interconnection and cooperation with a variety of things in real life such as Radio-Frequency Identification(RFID) tags, sensors, mobile phone, etc, through internet. IoT technologies which applied to these fields consist of sensor network technology and middleware, application. Currently, IoT technology is applied to various fields such as health care, home care, automotive, transportation, construction, agriculture, environment, food, and etc, based on its technologies. This paper focuses on discussion of the IoT development trend in game field. In order to achieve this purpose, first, the IoT technologies for game development based on sensor network technology and middleware, application is mentioned. Second, covers serious game and gamification that is expected to be a growing that is expected to be a growing, by applying IoT technologies to the game field. It can help for game developers by using IoT technologies.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.424-426
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• 2005

본 논문에서는 센서 네트워크에서 수명을 늘리기 위한 기존의 통신 프로토콜 중에서 모바일 에이전트가 있는 환경에서 전체 네트워크 트래픽 량을 줄여 더욱더 수명을 늘리기 위해서 클러스터를 도입한다. 고정된 위치에서 싱크가 데이터를 수집할 경우 싱크 한 홉 내에 있는 노드들이 에너지를 빨리 쓰기 때문에 네트워크 파티션이 일어나기 쉽다. 이를 해결하기 위해 모바일 에이전트를 이용하여 네트워크 수명을 연장하는 방법이 연구되었다. 하지만, 모바일 에이전트가 이동을 하게 되면 전체 네트워크의 트래픽 양이 많아진다. 늘어난 트래픽을 줄이기 위해 모바일 에이전트가 있을 때 클러스터링의 성능을 분석하고 에너지 효율적인 클러스터 방법에 대해서 제안한다.