• Journal of Sensor Science and Technology
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• v.16 no.4
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• pp.247-253
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• 2007

Low power consumption sensor network platform (sensor node) for sensor networking with IEEE 802.15.4 protocol was fabricated. The sensor node used ceramic bar type antenna for increasing RF signal performance and decreasing PCB size occupied by antenna. The communication range of the fabricated sensor node was about $20{\sim}30$ m in open environment with 915 MHz frequency bandwidth and well supported by Tiny OS. The sensor node have good connectivity with various external devices by RS-232, I2C, analogue and digital expansion board, hence, this sensor node can be applied to various applications in wireless sensor network and ubiquitous sensor network.

• Journal of Engineering Education Research
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• v.13 no.2
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• pp.7-11
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• 2010

As the development of the computer and communication technologies, the ubiquitous society can be realized to the world early in the future. Thus, the localization system in Wireless Personal Area Network (WPAN) is required for many users of ubiquitous society to provide the ubiquitous computing based applications in respective of anytime and anywhere. In this paper, we propose the distance measurement scheme that is based on the distance measurement using RSSI (Received Signal Strength Indicator) of sensor module considering of two distance conditions for the localization system using Zigbee in WPAN. Also, the localization errors of the proposed scheme are analyzed in the three scenarios that the mobile module tracks in the in $6m{\times}6m$ scaled experimentation area. In addition to this, the monitoring subsystem is developed using GUI (Graphical User Interface) in order to monitor the location of the moving objects accurately and user-friendly.

• Journal of Information Technology Applications and Management
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• v.14 no.2
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• pp.1-10
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• 2007

The ubiquitous computing system is expected to be widely utilized in digital home, logistics control, environment/disaster management, medical/health-care services and other applications. The ubiquitous sensor network (USN) is a key infra-structure of this system. Nodes in the USN are exposed to adverse environments and required to perform their missions with very limited power supply only. Also the sensor network is composed of much more nodes. In case some node consumes up its power capacity under a certain required level, the network topology should change and re-routing/ re-transmission of data is necessitated. Resultantly communication protocols studied for conventional wireless networks or ad-hoc networks are not suitable for the sensor network. Schemes should be devised to control the efficient usage of node power in the sensor network. This paper proposes a routing algorithm to enhance the efficiency of power consumption for USN node and analyzes its performance by simulation.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1536-1542
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• 2008

As information technology has been rapidly developed, it is expected that the needs of ubiquitous for information on construction, maintenance and operational processes in railway field will arise. U-Rail system, for which information ubiquitous in railway field, can be defined as the human centered future railway system that enables to perform real-time state indication and auto information generation and its transmission by interchanging information organically among railway suppliers, users, and operator. In this paper, we analyzed main components of U-Rail system and its service items from the view of information technology and communication network technology, with focusing on railway field.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.3
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• pp.112-121
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• 2009

National government established a new law to solve the problems and to support u-City projects. Nevertheless there are still some issues which are a lack of the contents on national plan, connecting restriction among the communication networks between public institutions, a shortage of funds. This study investigated and analyzes these issues, and proposed some ideas to solve them.

• Journal of information and communication convergence engineering
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• v.13 no.1
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• pp.15-20
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• 2015

The limited battery power in the mobile environment, lack of sufficient wireless bandwidth, limited resources of mobile terminals, and frequent breakdowns of the wireless network have become major hurdles in the development of mobile cloud computing (MCC). In order to solve the abovementioned problems, This paper propose a proxy-based MCC framework by adding a proxy server between mobile devices and cloud services to optimize the access to cloud services by mobile devices on the network transmission, application support, and service mode levels. Finally, we verify the effectiveness of the developed framework through an experimental analysis. This framework can ensure that mobile users have efficient access to cloud services.

• Journal of information and communication convergence engineering
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• v.5 no.3
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• pp.254-258
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• 2007

Recently, ubiquitous computing in being actively researched and one of the main technology in ubiquitous computing environments is recognized as RFID system. The RFID system has much benefits but simultaneously has some problems such as user's privacy violation. In this paper, in order to improve the survivability of its nodes, it should build available simulation surrounding sensor nodes. Also, In the proposed cryptosystems we use a new hash function for user authentication and a stream cipher based on LFSR(Linear Feedback Shift Register) for message encryption and decryption. Moreover, each algorithm is programmed with C language and simulated on IBM-PC system and we analyze the randomness properties of the proposed algorithms by using statistical tests.

• IE interfaces
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• v.20 no.4
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• pp.560-567
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• 2007

The opening of ubiquitous computing era prompted rapid increase in information transfer between human and computer. Such changes in computing environment requires new computing interface. In this paper, we develop a user interface prototype and framework using Avatar in Ubiquitous computing environment, which can support an active communication between human and computer based on context information. To develop the new interface, its conceptual framework with specific context information is designed in advance. In addition, this study suggests the future goal of user interface using Avatar by suggesting the requirements of constructed prototype.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.2
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• pp.105-111
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• 2010

The purpose of this study was to detect early children with hyperactivity which is one of the symptoms of Attention Deficit-Hyperactivity Disorder (ADHD). This study used two methods: K-CBCL and observation of children's behavior. K-CBCL was done online by parents at home. For observation of children's behavior, the school asked children to wear a 3-axis accelerometer on their wrists. The data from K-CBCL and 3-axis accelerometer were analyzed and clustered to separate hypersensitive children from ordinary children. This experiment confirmed that 3-axis accelerometer which is one of Ubiquitous techniques and the K-CBCL questionnaire were helpful for detection of hypersensitive children.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.1
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• pp.23-27
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• 2006

As a pervasive healthcare application to help medication of elderly patients, the smart compliance monitors have been recently proposed. In this paper, we present a new smart drug/medicine pack (SDP) for ubiquitous medication monitoring, for which the packaging is either paper packet or blister pack. This ubiquitous compliance monitor is composed of several SDPs and a Bluetooth equipped PDA phone. The SDP is a wireless module that monitors the medication consumption unobtrusively by transmitting the sensed data of 'drug removal' events to the medical center and by reminding patients when they take a dose on their mobile phone. The communication between SDP modules and PDA is realized via Bluetooth. The PDA is basically embedded to indicate the medication record and to alert every prescribed medication time during treatment. Experimental results show that the proposed system works exactly when the SDPs are far within about 2 [m] from PDA.