• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.6
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• pp.26-36
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• 2009

ad-hoc network is self-constructed by mobile hosts without any infrastructure. And the hosts collaborate with each other for routing packet by means of multi-hop communication. But it is too hard to deploy ad hoc network at the large area because of the salability problem caused by low network throughput. network throughput decrease is due to contention on the air among the neighbor host and single interface limitation, and broadcast flooding through overall network. In this paper, to solve the ad hoc scalability problem, we propose mesh network based scalable hierarchical ad hoc architecture, and also propose the adaptation methods for inter-working with the host not including ad hoc functions and the legacy infra-network.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.6
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• pp.89-95
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• 2008

The introduction of wireless information technology gives rise to new mobile services in all kinds of areas of out daily life. Mobile healthcare system is a production of composite ICT (Information and Communication Technology) which focused on signal sensing, processing, and communication in wireless environment. The mobile and wireless revolution promises not only expanded access to patient health information, but also improved patient care. In this paper, we describe a surrogate host based mobile healthcare information system which utilized Grid computing for real-time ECG signal processing. The surrogate host provides seamless interface between mobile device and Medical Grid portal. The security extension of GSI (Grid Security Infrastructure) allows mobile users to access Grid portal in a secure and convenient manner. The presented system architecture can be used as a secure enterprise mobile healthcare system for hospital physicians.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.4
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• pp.720-740
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• 2011

Wi-Fi-enabled portable devices have recently been introduced into the consumer electronics market. These devices download or upload content, from or to a host machine, such as a personal computer, a laptop, a home gateway, or a media server. This paper investigates the fairness among multiple Wi-Fi-enabled portable devices in a home network when they are simultaneously communicated with the host machine. First, we present that, a simple IEEE 802.11-based home network suffers from unfairness, and the fairness is exaggerated by the wireless link errors. This unfairness is due to the asymmetric response of the TCP to data-packet loss and to acknowledgment-packet loss, and the wireless link errors that occur in the proximity of any node; the errors affect other wireless devices through the interaction at the interface queue of the home gateway. We propose a QoS-provisioning framework in order to achieve per-device fairness and service differentiation. For this purpose, we introduce the medium access price, which denotes an aggregate value of network-wide traffic load, per-device link usage, and per-device link error rate. We implemented the proposed framework in the ns-2 simulator, and carried out a simulation study to evaluate its performance with respect to fairness, service differentiation, loss and delay. The simulation results indicate that the proposed method enforces the per-device fairness, regardless of the number of devices present and regardless of the level of wireless link errors; furthermore it achieves high link utilization with only a small amount of frame losses.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.179-186
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• 2012

Nowadays, the multihomed host equipped with multiple network interfaces has been interested research in next generation wireless network, because the mobile users expect that they can be able to access services not only anywhere, at any time and from any network but also simultaneously. This paper addresses the mobility simulation model of the multihomed node for supporting MIPv4 and MIPv6 function in an interworking of Worldwide Interoperability for Microwave Access (WiMAX) and IEEE 802.11 WLAN. The multihomed node with two air interfaces has been developed based on WiMAX and WLAN workstation node model in simulation software. The main point of the developed model is to support both MIPv4 and MIPv6 function, and provide network selection policy for the multihomed node between WiMAX and WLAN network. Based on the received Router Advertisement along with the interface number, we can manage the access interfaces in ordered list to make handover decision while the multihomed node is moving. In the end of this paper, the simulation scenarios and results are shown for testing MIPv4 and MIPv6 function.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.3
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• pp.1-7
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• 2007

RFID ( Radio Frequency IDentification ) is an automatic realization technology that recognizes things or a person with data stored tag, card, label, etc that have microchip by using radio frequency. Automation and efficient data base management(DBM) of system are possible by replaces using Bar-code that is used widely with using RFID. In this paper, we designed RFID tag data format that used to recognize information of books in Library and implemented library management system. Library management system is divided checking collection of books, self-loaning books system, self-returning books system, management books information system for a librarian. RFID leader realized information of tag and transfer it to host computer through RS-232 interface. Host computer processes and operates information with middleware. System that we made is depending on executive system for a librarian.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.4
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• pp.871-876
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• 2005

Theme park automation system is developed by using the RFID sensor reader, IIS web server, ASP.NET and MSSQL database in this paper. Its operation is that park entrance people checked automatically when he who possessed the ta8 passed the reader acquisition bound and its tag information is sent to the host computer through the RS-232 data acquisition system. Tag information and time data will be stored in the RFID database tables and reused to extract and distribute the entrance people for the purpose of each arrangement of each entertainment devices. First of all, we developed interface program between host and reader and then, programmed the related web site and database connection function using ASP.NET with $C\#$ and MSSQ. We also design and make an production of external Ant. to extend the acquisition range up to $30\~40$ cm using copper PCB plate. We confirmed the performance through the RFID test bed site.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.10
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• pp.1957-1963
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• 2017

This paper has proposed a new-type groundwater auto-monitoring system based on Multi-Sensor Device. The system adopted Multi-Sensor Device as host computer of data acquisition, used Windows Mobile which was prevalent operation system of Multi-Sensor Device. It adopted serial port CAN and RS485 as the communication interface between goundwater sensor Device and monitor host machine and utilized serial-linked multi-sensor design to measure effectively according to the depth of groundwater. We present a design for a groundwater monitoring system based on a network of wirelessly linked sensors. The proposed solution will enable groundwater researchers and decision makers to have quick access to the groundwater data with less effort and cost. Though our design is initially meant for groundwater monitoring, it can be easily adapted to other fields of environmental monitoring.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.1B
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• pp.19-25
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• 2006

It's for USB to be used more frequently than another I/O devices. The Universal Serial Bus is the most successful interface in PC history. It's already the do facto interconnect for PCs, and has proliferated into consumer electronics(CE) and mobile devices as well. USB has built on many killer applications, many CE devices, many interfaces. The tangle of wires among the number of devices in your home demands wireless technology. If our devices is unwired, it solves the tangle of wires. In this paper we want to use Legacy USB functionalities, portabilities, multimedia capabilities with wireless interconnection. This paper is related to a study of USB implementation without wires. This paper is related to make the hub function of USB cordless, so it will connect host with devices without wires. In case making USB wireless, it must support the above functionalities. Moreover, It needs the data structure and the resources for host functionalities, e.g. ETD(Endpoint Transfer Descriptor), data memory. This will benefit a convenient use of USB.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2344-2346
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• 2002

A vacuum control system has been developed for using Ethernet Multi Serial Device Severs (EMSDS) for the Pohang Accelerator Laboratory (PAL) storage ring. There are 124 vacuum ion pumps at the storage ring. It was a very important problem to solve the problem how to control such a big number of vacuum pumps distributed around the ring. After discussions, we decided to develop a serial to ethernet interrace device sever that will be mounted in the control system rack. It has a 32-bits microprocessor embedded Linux, 12 ports RS485 (or RS232) slave interface. one channel 10/100BaseTx ethernet host port, one channel UART host port, and 16 Mbytes large memory buffer. These vacuum pumps are connected to Ion-Pump serial controllers, which chop the AC current so as to control the current in the pumps. The EMSDS connect either 100BaseTx or 10BaseT ethernet networks to asynchronous serial ports for communication with serial device. It can simultaneously control up to 12 ion-pump serial controllers. 12 EMSDS are connected to a personal computer (PC) through the network. The PC can automatically control the EMSDS by sending a set of commands through the TCP/IP network. Upon receiving a command from a PC running under Windows2000 through the network, the EMSDS communicate through the stave serial interrace ports to ion-pump controller. We added some software components on the top of EPICS (Experimental Physics and Industrial Control System) toolkit.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.4 s.316
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• pp.36-44
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• 2007

In this paper, we implement the speech & face recognition system to support various ubiquitous sensor network application services such as switch control, authentication, etc. using wireless audio and image interface. The proposed system is consist of the H/W with audio and image sensor and S/W such as speech recognition algorithm using psychoacoustic model, face recognition algorithm using PCA (Principal Components Analysis) and LDPC (Low Density Parity Check). The proposed speech and face recognition systems are inserted in a HOST PC to use the sensor energy effectively. And improve the accuracy of speech and face recognition, we implement a FEC (Forward Error Correction) system Also, we optimized the simulation coefficient and test environment to effectively remove the wireless channel noises and correcting wireless channel errors. As a result, when the distance that between audio sensor and the source of voice is less then 1.5m FAR and FRR are 0.126% and 7.5% respectively. The face recognition algorithm step is limited 2 times, GAR and FAR are 98.5% and 0.036%.