• Journal of Korea Multimedia Society
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• v.13 no.8
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• pp.1221-1234
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• 2010

MANET(Mobile Ad-hoc Network)s have been researched primary at routing protocols and at the guarantees of QoS(Quality of Service) for mobile environments. Otherwise the Ubiquitous Sensor Networks (USNs) have some limitations in power energies and in processing of sensing data, as well as their network topologies are frequently changed by fading off and node failures. Thus we should redesign network protocols with concerning to energy efficiency for the USNs above all. In this paper, we focus on the protocol interface for managing for USNs based on the surveys. And then we figure the topology of USNs out and design the network protocol interface to make power saved, with data gathering and processing more efficient using our designed packet structures.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.279-283
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• 2005

요즘 사회에 이슈가 되는 것을 꼽으라면 사람들은 주저 없이 Ubiquitous를 말할 것이다. Ubiquitous란 사용자가 네트워크나 컴퓨터를 의식하지 않고 장소에 상관없이 자유롭게 네트워크에 접속할 수 있는 정보통신 환경을 의미한다. Sensor Network과 RFID는 Ubiquitous 환경을 구축하는데 필요한 아주 중요한 요소이다. 본 논문에서는 기존에 구현된 Sensor Network과 RFID의 기술을 이용하여 Ubiquitous Healthcare system의 일환으로 '노약자 관리 시스템 구축'에 대해 서술하고자 한다. 특별한 관리가 필요한 노약자(어린아이, 치매성 질환을 가진 노인, 정신지체 장애인 등)를 대상으로 보호자와 응급센터와의 네트워크를 구축하고 기반시설과의 연동을 통해서 보다 체계적이고 효율적인 관리 시스템에 대해서 서술한다. Sensor Network과 RFID의 기본적인 개념, 노약자 관리시스템의 필요성, 제안된 관리시스템에 관해 서술한다.

• The Journal of the Korea Contents Association
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• v.8 no.1
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• pp.143-151
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• 2008

In this paper, we have implemented a ubiquitous healthcare system that can measure and check human's health in anytime and anywhere. The implemented prototype are composed of both front-end and back-end. The front-end have several groups: environment sensor group such as temperature, humidity, photo, voice sensor, health sensor group such as blood pressure, heart beat, electrocardiogram, spo2 sensor, gateway for wired/wireless communication, and RFID reader to identify personal. The back-end has a serial forwarder to propagate measurment results, monitor program, and medical information server The implemented sensor node constructs a sensor network using the Zigbee protocol and is ported the tinyOS. The data gathering base node is linux-based terminal that can transfer a sensed medial data through wireless LAN. And, the medical information server stores the processed medical data and can promptly notify the urgent status to the connected medical team. Through our experiments, we've confirmed the possibility of ubiquitous healthcare system based on sensor network using the Zigbee.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.2
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• pp.378-383
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• 2012

Nowadays, the study is going on develop USN(Ubiquitous Sensor Network) with diffusion of the internet and development of computer network technology. USN sensor nodes equipped with various types of sensors provide sensor information to each individual sensors. To do this there needs standardized data description language for allowing many people to use based on XML in web services environment. In this paper, USN sensor information required for application services in a standardized form to describe the sensor data representation language was designed. USN-based technology utilized in the field, and will be utilized for service activation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.5
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• pp.854-859
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• 2009

Many pilot projects are developed using USN(Ubiquitous Sensor network). Recently USN has more attention to be used for the applications of circumstance monitoring. In order to acquire information from sensor nodes, sensor nodes need a RF transceiver. In this paper we describe the design of a RF transceiver, based on IEEE 802.15.4, for sensor nodes operating in 2.4GHz frequency band. The architecture to be implemented and the electrical performance specifications satisfied IEEE 802.15.4 are presented. The noise figure of a receiver, selectivity, phase noise of a frequency synthesizer, transmitter's linearity and spectrum mask are derived as a design parameters from the specifications of IEEE 802.15.4.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.10
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• pp.4531-4535
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• 2011

In this paper, USN(Ubiquitous Sensor Network) is used in the structure of the tree routing was implemented in embedded systems. Tree Routing in the USN to the sink node to transmit sensor data is one of the techniques. When routing, sensor data is transmitted based on pre-defined ID according hop number. In order to have optimal routing path, the current state of the wireless sector and the sensor node informations were used. Also, received sensor data and the results of the tree routing by implementing an embedded system. This embedded system can be applied to a portable sensor information collecting system.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.6
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• pp.358-370
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• 2007

Software simulations have been widely used for the design and application development of a wireless sensor network that is an infrastructure of ubiquitous computing. In this study, we develop a sensor network simulator that can verify the behavior of sensor network applications, estimate execution time and power consumption, and simulate a large-scale sensor network. To implement the simulator, we use an instruction-level parallel discrete-event simulation method. Instruction-level simulation uses executable images loaded into a real sensor board as workload, such that it results in the high degree of details. Parallel simulation makes simulation of a large-scale sensor network possible by distributing workload into multiple computers. The simulator can predict the amount of power consumption based on operating time of modules in a sensor node and counting the number of executed instructions by kind. Also it can simulate ubiquitous applications with various scenarios and debug programs. Instruction traces used as workload for simulations are executable images produced by the cross-compiler for ATmega128L microcontroller.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.1
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• pp.193-214
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• 2017

In this paper, we study the problem of network utility maximization in a CSMA based multi-hop wireless network. Existing work in this aspect typically adopted continuous time Markov model for performance modelling, which fails to consider the channel conflict impact in actual CSMA networks. To maximize the utility of a CSMA based wireless network with channel conflict, in this paper, we first model its weighted network capacity (i.e., network capacity weighted by link queue length) and then propose a distributed link scheduling algorithm, called CSMA based Maximal-Weight Scheduling (C-MWS), to maximize the weighted network capacity. We derive the upper and lower bounds of network utility based on C-MWS. The derived bounds can help us to tune the C-MWS parameters for C-MWS to work in a distributed wireless network. Simulation results show that the joint optimization based on C-MWS can achieve near-optimal network utility when appropriate algorithm parameters are chosen and also show that the derived utility upper bound is very tight.

• Convergence Security Journal
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• v.12 no.1
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• pp.43-48
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• 2012

In this paper, the requirements for information security are presented in the ubiquitous ecological(u-Eco) city. The various definition of ubiquitous city is analyzed first, the concept of the u-Eco City, services and major projects are then presented. The framework of the integrated operating center for u-Eco city is proposed, the privacy, data security and network facility protection in the center are analyzed. Unlike to previously proposed security algorithms, the light-weight encoding algorithms(such as block/stream encoding, pseudo-random generator, hash function, and public key encoding) in the u-Eco city center are required to communicate the information in the ubiquitous sensor network. Furthermore, the principal policies guaranteeing the secrecy and authentication for the private information are also presented.

• Journal of Biomedical Engineering Research
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• v.26 no.5
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• pp.331-335
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• 2005

The fusion technology of small sensor and wireless communication was followed by various application examples of the embedded system, where the social infrastructural facilities and ecological environment were wirelessly monitored. In addition, this technology represents the primary application area being extended into the healthcare field. In this study, a body area network for ubiquitous healthcare is presented. More specifically this represents a wireless biomedical signal acquisition device characterized by small size, low power consumption, pre-processing and archiving capability. Using this device, a new method for monitoring vital signs and activity is created. A PDA-based wireless sensor network enables patients to be monitored during their daily living, without any constraints. Therefore, the proposed method can be used to develop Activities of Daily Living (ADL) monitoring devices for the elderly or movement impaired people. A medical center would be able to remotely monitor the current state of elderly people and support first-aid in emergency cases. In addition, this method will reduce medical costs in society, where the average life expectancy is increasing.