• Proceedings of the Korea Society of Information Technology Applications Conference
• /
• 2005.11a
• /
• pp.237-241
• /
• 2005

We present a device model for organic light emitting diodes(OLEDs) which includes charge injection, transport, recombination, and space charge effects in the organic materials. The model can describe both injection limited and space charge limited current flow and the transition between them. Calculated device current, light output, and quantum and power efficiency are presented for different cases of material and device parameters and demonstrate the improvements in device performance in bilayer devices. These results are interpreted using the calculated spatial variation of the electric field, charge density and recombination rate density in the device. We find that efficient OLEDs are possible for a proper choice of organic materials and contact parameters.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.3C
• /
• pp.233-240
• /
• 2012

Unlike traditional factory environment, in an industrial factory network applied wireless sensor network technologies, all procedures of discovery, identification and verification of devices should be performed in an automatic fashion. To address these challenges, we design a management system using the device registry server that we propose in this paper. In the phase of device discovery, the proposed system utilizes properties of routing protocol running in factories. Also, in the phase of identification and verification, the system uses unique and general information of a device stored within the device registration server. Such a way allows management system to reduce implementation complexity and to easily manage devices in a factory applied with a wireless network consisting of heterogeneous devices.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.7
• /
• pp.1533-1540
• /
• 2012

u-Life care device collect body bio formation, and classify and store them in exercise patterns. Afterwards, the devices send the data through bluetooth wireless communication to the smart phones which set Google Android operation system at regular intervals. The information is checked out through application. u-Life care device calculates calories spent a day after monitoring activity quantity with 3-axis acceleration sensor. The device judges the status of health through body data mining and consults tailored exercise treatment. When sending body data, the device sends them in smart phone through Blue Tooth wireless communication at once. So, as a strong point, the device doesn't need mobile gateway or home gateway used for sending to web server information sensed from exercise life care products.

• Journal of Information Technology Services
• /
• v.11 no.4
• /
• pp.181-194
• /
• 2012

The one of the most meaningful change in the recent ubiquitous environment is the omnipresence of public digital display device for providing ubiquitous information. It is the important issue to provide publicity as well as adaptive information to each user in the field of the public digital display device. This research proposes the idea ensuring fast response speed by the selection of user preference function. The preference function is selected by statistics using Zipf distribution in the system comprising mobile device and digital display device based on NFC (Near Field Communication). The idea is proved by CPM-GOMS model and the improvement of user response can be achieved.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2007.05a
• /
• pp.259.1-259.1
• /
• 2007

• International Journal of Internet, Broadcasting and Communication
• /
• v.14 no.1
• /
• pp.122-128
• /
• 2022

Minimization of human casualties in disaster situations is of paramount importance. In particular, if a marine disaster occurs, it can be directly connected to human casualties, so prompt action is needed. In the event of a marine disaster, the route and location of movement should be identified and life tubes should be used to float on the water. This paper designs and proposes an emergency IoT notification system that can quickly rescue drowning people. The maritime emergency IoT notification system consists of four main types. First, an emergency IoT device that detects the expansion of the life tube and delivers location and situation information to the emergency IoT notification server. Second, an emergency IoT web server that manages emergency information and provides notification. Third, a database server that stores and manages emergency IoT notification information. And finally, an emergency notification app that can receive and respond to emergency notification information. The emergency IoT device consists of a TPMS(Tube Pressure Monitoring System) device that checks the pressure value of the TPMS in real time and sends it to the IoT device, and an IoT device that sends the rescuer's voice information and emergency information to the emergency IoT server. Emergency information is delivered using the MQTT(Message Queuing Telemetry Transport) protocol, and voice information is delivered to the IoT server as HTTP FormData.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.10a
• /
• pp.811-814
• /
• 2007

Mobile device will be able to use the various contents from the advancement of the wireless Internet and mobile device manufacture technique. Each devices HTTP headers about under using provides terminal information to contents provider which is provided the contents which is suitable in device. But there is not a standard for a terminal information proηsion and when using the contents of service network outside, interoperability problems mobile communication it will provides terminal information in different method. International Organization for Standard OMA UAProf about under using it solved interoperability problems from outside. But about under using it provides terminal information, MMS support and Smart Card support, against an external storage space supporting information it is not seen clearly UAProf not to be, it will not be able to provide terminal information which is complete. This paper hereupon it designed UAProf in base which provides the contents which has become optimize to the mobile device of domestic environment the mobile device description language which expresses device information which is necessary.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.19 no.8
• /
• pp.1446-1452
• /
• 1994

In this paper, Weibull distribution is applied to the lifetme distribution of a device. The method of Bayesian estimate used to estimate requiring parameter in order to predict lifetime of device using accelerated lifetime test data, namely failure time of device. The method of Bayesian estimate needs prior information in order to estimate parameter. But this paper proposed the method of parameter estimate without prior information. As stress is temperature, Arrhenius model is applied and the method of linear estimate is applied to predict lifetime of device at the state of normal operation.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.18 no.9
• /
• pp.2805-2817
• /
• 2024

This study focuses on the performance of device-to-device (D2D) communications in underlay cellular networks by analyzing key metrics such as successful transmission probability, coverage probability, and throughput. Under the homogeneous Poisson point process (PPP) spatial distribution of full-duplex (FD)-D2D users in cellular networks, stochastic geometry tools are used to derive approximate expressions for D2D users' coverage probability and throughput. In comparison to the conventional half-duplex (HD) communication mode, when the self-interference cancellation factor β reaches -95 dB, there is a substantial improvement in the throughput of FD-D2D users, nearly doubling their gain. Additionally, experimental results demonstrate that the Newton iterative algorithm can be used to optimize the targeted signal-to-interference-plus-noise-ratio (SINR) threshold of users within the range of (10, 20) dB.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.15 no.3
• /
• pp.29-36
• /
• 2019

With the rapid development of 5G technology, more and more network functions are interconnected and more popular. In order to effectively manage emerging network concepts, it allows any device object in the real world to be connected anywhere and at any time through the integration of device object recognition, interaction and raw data collection technologies. In addition, IP Multimedia Subsystem (IMS) is an architecture framework for transmitting IP-based information to the device object which can be represented as end user. Therefore, the Internet of Things and IP Multimedia Subsystem (IoT-IMS) communication platform can provide a convenient and fast way for user or device objects to deploy new application services effectively. In particular, in order to collect and manage the device information from IoT effectively in the IoT-IMS communication platform, an IoT Information Gateway (IIG) is proposed. Through the IoT Application Service (AS) scenario, the collected device information can be easily observed and managed in a unified way.