• The Journal of Korean Association of Computer Education
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• v.15 no.6
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• pp.75-82
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• 2012

The sensor registry system has been proposed to interpret and process semantics of sensor data independently of heterogeneous sensor networks. However, the existing sensor registry system provides the static processing method. In other words, the existing system reduces the overall performance because it executes unnecessary operations and does not consider data scope to be used. To resolve the problem of the existing sensor registry system, this paper proposes a performance enhancement model based on sensor metadata reusability and scoping. The proposed model in this paper provides a function that can decide a proper scope of sensor metadata from the sensor registry system. The proposed model improves the overall performance by providing reusability of sensor metadata. This paper also shows the advantages of the proposed model through the comparative performance evaluation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1721-1726
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• 2014

The sensor network technology for core technology of ubiquitous computing is in the spotlight recently, the research on sensor network is proceeding actively which is composed many different sensor node. The major traffic patterns of plenty of sensor networks are composed of collecting types of single directional data, which is transmitting packets from several sensor nodes to sink node. One of the important condition for design of sensor node is to extend for network life which is to minimize power-consumption under the limited resources of sensor network. In this paper analysis used routing protocols using the network simulation that was used second level cluster structure to reduce delay and power-consumption of sensor node.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.12
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• pp.2084-2093
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• 2016

It is crucial to predict water temperature for aquatic ecosystem studies and management. In this paper, we first address challenging issues in predicting water temperature in a real time manner and propose a distributed computing model to address such issues. Then, we present an Artificial Neural Network (ANN)-based water temperature prediction model developed for the Soyang River and a cyberinfrastructure system called WT-Agabus to run such prediction models in an automated and real time manner. The ANN model is designed to use only weather forecast data (air temperature and rainfall) that can be obtained by invoking the weather forecasting system at Korea Meteorological Administration (KMA) and therefore can facilitate the automated and real time water temperature prediction. This paper also demonstrates how easily and efficiently the real time prediction can be implemented with the WT-Agabus prototype system.

• The KIPS Transactions:PartC
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• v.16C no.1
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• pp.109-116
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• 2009

Recently, there are many researches to realize context-awareness service that recognizes surrounding environments as context and provide the citizens with pervasive convenience based on ubiquitous computing technology. In the u-City, various sensors collect information as context, and citizens will receive various context-awareness service, making use of their wireless and mobile devices and the infrastructures of the u-City. We designed ontology that is useful to structure information of sensor or device that is linked to networks and use OWL (Web Ontology Language) that can express information of mutual relation and partial situation. And we propose a context-aware reasoning system for personalized u-City services based on collected context information and user's intention.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.23-29
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• 2011

We try to build the base for implementation of smart water treatment plant through identifying status by data acquisition such as temperature, humidity, flow, level, pump status and CCTV by using USN terminal such as Zigbee, Wi-Fi, UHF at the center of the flowmeter calibration center in K-water institute. The data obtained from various sensors is transmitted to data processing device through different types of USN network, the processed data is implemented to monitor by smart phone and we try to perform low cost and high efficient USN-based pilot project by implementing remote monitoring system using network performance analysis and mobile devices.

• Journal of the Korea Society of Computer and Information
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• v.12 no.1 s.45
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• pp.89-98
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• 2007

In these days, the use of context in application running on mobile devices such as PDAs and smart Phone has become a crucial requirement for several research areas, including ubiquitous computing. mobile computing. Previous middlewares which support context provisioning uses single strategy. But, this paper proposed middleware integrated multiple strategies for context provisioning, namely internal sensors-based, external infrastructure-based, and distributed provisioning in ad hoc networks. Applications can query needed context items using SQL like context query language and require context information to use different provisioning mechanisms depending on resource availability and presence of external infrastructures.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.277-279
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• 2003

본 논문에서는 편재 컴퓨팅(ubiquitous and pervasive computing) 환경에 입력 시스템으로 사용하는 센서 네트워크에서 측정한 데이터의 품질 (sampling rate and quantization depth) 을 보증하며 네트워크 트래픽 또는 소모전력과 같은 비용을 최소화하기 위한 방법으로, 휴리스틱 알고리즘에 의한 비주기적 샘플링과 신뢰성 있는 전송규약을 사용하는 비주기적 전송방식을 제안한다. 그리고 제안한 비주기적 전송방식에 핵심기술인 신뢰성 있는 전송 규약의 비용을 최적화하기 위한 방법으로 ACK방식과 NACK방식을 패킷 에러율과 동일한 라우터를 사용하는 이웃 노드의 수와 같은 네트워크 상황에 따라 상보적으로 사용하는 상보적 방식(alternative method)을 제안하고, 전체 통신규약을 설계하며, 해석을 통해 성능을 분석하고, 네트워크 상태에 따라 두 방식의 성능상의 우열이 전환되는 전환점을 유도한다. 제안하는 상보형 신뢰성 있는 전송규약은 전체 센서 네트워크에서 처리되는 패킷의 비트 수를 최소화해, 각 노드의 총 전력 소모의 20-60%를 차지하는 통신모듈의 소비 전력을 줄일 수 있어 전력소모를 크게 개선 할 수 있다. 나아가서 다양한 센서 네트워크에서 설계한 전송규약을 바탕으로 하는 제안하는 비주기적 전송방식을 활용한다면 최적의 비용으로 측정하는 데이터의 품질을 보증할 수 있다.

• Journal of KIISE:Information Networking
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• v.36 no.4
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• pp.330-338
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• 2009

Various applications based on the location information of things are developed as entering by the ubiquitous computing age. Wireless sensor networks are suitable to indoor location-based service because of the important features such as low-power consumption, low-cost, easy deployment, etc. To recognize the distance between nodes, the indoor location-based system transmits both ultrasound signal and radio signal periodically. However, increment of the number of deployed sensor nodes make lots of collision and interference among the signals and it can degrade the accuracy of location-based system. In this paper, we propose a beacon management mechanism to increase the probability of transmission chance to the nearest beacon from the listener. It can minimize collision and interference and reduce the error probability due to the characteristics of ultrasound.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.3
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• pp.627-633
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• 2007

This paper describes position tracking system of a container trailer approaching to a gantry crane for loading or unloading a container into or from a ship, respectively. Proposed position tracking system informs the trailer driver of right position to stop the car under a gantry crane. To measure the location of a trailer, we used Cricket Mote modules which adopted RF and ultrasound technology. We present an elaborate method to improve position errors occurring at sensing and calculate three dimensional position by triangulation along with how to reduce location tracking interval for real-time monitoring. The location information was transmitted to a Personal Digital Assistant (PDA) periodically through Bluetooth communication for guidance of the trailer driver. In indoor and outdoor tests, position errors were less than 3 cm and location tracking interval was 0.5 second on average.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.9
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• pp.1793-1798
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• 2007

Recently there are some trends to construct smart home system infrastructure depending upon the development of Information and Communication Technology. Also requirements of the Ubiquitous Healthcare Systems at home which can monitor the status of health continuously are increased rapidly comparing with hospitals. Healthcare service can be divided into two categories. The first one is Alarm Service that can be used for the emergency status and the other one is Remote Support Service which can monitor the patient including home environments and give those diagnosis information to medical office or to his family. Generally wired networks and fixed healthcare measuring system have some limits to transmit reliable realtime based information for both categories described above comparing with portable monitoring system. Getting over the inefficiency we will design and implement portable healthcare system under the wireless Zigbee network environments.