• Proceedings of the Korean Information Science Society Conference
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• 2011.06d
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• pp.230-231
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• 2011

In this paper, we propose a rendezvous mechanism for cognitive radio networks. In this mechanism, no prior knowledge of wireless nodes is required and it is totally distributed. Node can simply choose one of two strategies to rendezvous with its neighbors. The main benefit of this mechanism is eliminating the use of common control channel and centralized controller.

• Proceedings of the IEEK Conference
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• 2001.06e
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• pp.47-50
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• 2001

Nowadays ARM7 core is used in many fields such as PDA systems because of the low power and low cost. It is a general-purpose processor, designed for both efficient digital signal processing and controller operations. But the advent of the wireless communication creates a need for high computational performance for signal processing. And then This paper has been designed a floating-point multiplier compatible to IEEE-754 single precision format for ARMTTDMI performance improvement.

• Proceedings of the KAIS Fall Conference
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• 2003.06a
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• pp.226-228
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• 2003

본 논문에서는 현재 산업현장에서 사용되고 있는 유선 콘트롤러와 무선 콘트롤러의 문제점을 보완하기 위해 컨벌루션 부호와 CRC부호를 적용한 무선 콘트롤러를 구현하였다. 콘트롤러의 제어를 위해 마이크로프로세서를 이용하였으며, 무선 콘트롤러의 신뢰도 향상을 위해 적용한 컨벌루션 부호는 구속장 k=3, 부호율 ½인 부호를 사용하였고, CRC 부호는 POLYNOMIAL함수를 X/sup 15/ ＋ X² ＋ 1로 사용하여 총 CRC비트 16비트(2바이트)가 되게 하였다. 또한 구현된 무선 콘트롤러를 무선환경에서 테스트하여 송수신시 정확하게 데이터의 송수신이 이루어짐을 확인하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.5
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• pp.271-279
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• 2014

In this paper, the two design techniques of the embedded system which provides a wireless image observation with temporary ad-hoc network are proposed and developed. The first method is based on the embedded system design technique for a nearly real-time wireless short observation application, having a specific remote monitoring node with a built-in image processing function, and having the maximum rate of 1 fps (frame per second) wireless image transmission capability of a $160{\times}128$size image. The second technique uses the embedded system for a general wireless long observation application, consisting of the main node, the remote monitoring node, and the system controller with built-in image processing function, and the capability of the wireless image transmission rate of 1/3 fps. The proposed system uses the wireless ad-hoc network which is widely accepted as a short range, low power, and bidirectional digital communication, the hardware are consisted of the general developed modules, a small digital camera, and a PC, and the embedded software based upon the Zigbee stack and the user interface software are developed and tested on the implemented module. The wireless environment analysis and the performance results are presented.

• Journal of Biomedical Engineering Research
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• v.25 no.6
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• pp.447-453
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• 2004

In the case of a capsule that can acquire and transmit images from the intestines, the size of the module and the battery capacity in the capsule are subject to restriction. The capsule must be swallowable and the battery must maintain the stable power during the capsule travels in the gastrointestinal tract. Therefore, it is important to control the endoscope using bi-directional wireless communication. In this study, encoder and decoder CPLD modules for bi-directional capsule endoscopes were designed and implemented. The designed controller for capsule endoscope can transmit the images of GI-track from inside to outside of the body and the capsules can be controlled by external controller simultaneously. The designed and implemented controller was verified by an in-vivo animal experiments. From these experiments, it was verified that the CPLD module for bi-directional capsule endoscope satisfied the design specifications.

• Journal of Korea Multimedia Society
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• v.2 no.3
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• pp.329-338
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• 1999

In this paper we propose a WATM MAC protocol called DTDD/PS (Dynamic Time Division Duplex using Poll/Select scheme). The idea of the DTDD/PS protocol is based that a radio cell is considered as queueing system. The MAC controller in base station is charged in coordinating terminals for the QoS requirement from each terminal. For that reason, terminals send it's own dynamic parameter represented its status, and controller controls the access of terminals and assigns time slots dynamically using received parameters. Therefore this system can satisfy the QoS of real-time service in wireless environments. To evaluate DTDD/PS protocol simulations are executed. In 25Mbps channel capacity, the voice and data coexist traffic situation, as the total number of terminal is increased, the delay of data terminals is increased rapidly. But the case of only increasing data terminals, the number of supported voice terminals is not varying. Therefore we can expect that DTDD/PS protocol can applied to multimedia traffic effectively.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.7
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• pp.93-102
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• 2017

Recently increasing usage of smartphones makes the Internet of Things (IoT) a leading technology that can collect and share data through sensor networks and wireless communication such as low-power Bluetooth (BLE). BLE-based application can provide operators more precise information on Automatic Door system by remotely diagnosing the system faults through wireless sensor networks and sensors around the Automatic Door. In this paper, a smart device with extended BLE module is implemented which can monitor and Control the system states and faults remotely without on-site diagnostic. while maintaining system integrity so that increase efficiency of time and costs for system management. We can use the results of this research as a basis in evaluating reliability of data between devices, extending communication module in Controller of obsolete Door systems, and establishing centralized monitoring systems in near future with multi-channel Door Controls.

• Journal of Digital Contents Society
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• v.19 no.7
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• pp.1237-1244
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• 2018

Currently the bottleneck in virtual reality's commercialization might be that high cost VR equipment is needed and interesting VR contents are not enough. The purpose of this paper is to solve these problems by implementing low-cost VR system with wireless controller and HMD(Head Mounted Display) using a smart phone and PC. The functions of real HMD are simulated by utilizing the display and embedded sensors of a smart phone. In that situation PC is in charge of processing huge data and is communicated with smart phone. And wireless controller is designed to make VR user's movement to be free. In addition, we made the several VR contents for testing our prototype system directly. Easy access to VR equipment could induce increasing number of users and investment. And it will be a big step toward improving VR technology and its commercialization.

• 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.1-9
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• 2007

An embedded system is implemented in this work by removing PCMCIA dedicate controller chip from ARM processor based embedded Linux system. In this paper, we propose PCMCIA interface architecture by using Ad hoc methods for wireless network. The proposed system is developed based on S3C2410A processor and it is interfaced with PCMCIA socket by using combinational digital logic circuits. It is interesting to observe that Ad hoc interface provides $97.9%{\sim}102.49%$ performance when compared with dedicate controller systems. The results indicate that the proposed method simplifies the system without loss of performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.3
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• pp.1063-1082
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• 2018

The concept of SDN (Software Defined Networking) endows the network with programmability and significantly improves the flexibility and extensibility of networks. Currently a plenty of research works on introducing SDN into wireless networks. Most of them focus on the innovation of the SDN based architectures but few consider how to realize the global perception of the network through the controller. In order to address this problem, a software defined carrier grade Wi-Fi framework called SWAN, is proposed firstly. Then based on the proposed SWAN architecture, a blueprint of introducing the traditional NSA (Network Situation Awareness) into SWAN is proposed and described in detail. Through perceiving various network data by a decentralized architecture and making comprehension and prediction on the perceived data, the proposed blueprint endows the controllers with the capability to aware of the current network situation and predict the near future situation. Meanwhile, the extensibility of the proposed blueprint makes it a universal solution for software defined wireless networks SDWNs rather than just for one case. Then we further research one typical use case of proposed NSA blueprint: network performance awareness (NPA). The subsequent comparison with other methods and result analysis not only well prove the effectiveness of proposed NPA but further provide a strong proof of the feasibility of proposed NSA blueprint.