• Journal of the Korean Society of Industry Convergence
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• v.16 no.4
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• pp.127-132
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• 2013

We describe a research about remote control of mobile robot based on voice command in this paper. Through real-time remote control and wireless network capabilities of an unmanned remote-control experiments and Home Security / exercise with an unmanned robot, remote control and voice recognition and voice transmission are possible to transmit on a PC using a microphone to control a robot to pinpoint of the source. Speech recognition can be controlled robot by using a remote control. In this research, speech recognition speed and direction of self-driving robot were controlled by a wireless remote control in order to verify the performance of mobile robot with two drives.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.5
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• pp.1053-1059
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• 2011

DMX512 protocol is a typical protocol which controls LED lighting system. It has a strong feature and can be used to a lot of lighting system. But LED control system with cable has a few problem because they have a lot of control cables. It is very difficult to set up the complex lighting. Furthermore if it is set up it is not easy to keep and recover the system from the out of order. So it is required Wireless Lighting Control System. This paper describes the proposal, design, and implementation of a novel method which can provide versatile light effects with the increased capability of the mobility and the number of universes for Wireless Lighting system. And then we implement experiment environment to control indoor lighting system controled by ZigBee and WLAN converter not having complicating control line. Data frames are transferred to DMX512 device by encapsulation and decapsulation to control color LED. In the same time give the method to solve the data bottleneck problem which can be comes out because of speed difference between Heterogeneous network and measure performance of control system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.278-283
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• 2000

As information communication technology developed we could check our blood pressure, pulsation electrocardiogram, SpO2 and blood test easily at home. To check our health at ordinary times is able though interlocking the house medical instrument with the wireless public data network This service will help the inconvenience to visit the hospital everytime and will save the individual's time and cost. In each house an organism data which is detected from the human body will be transmitted to the distance hospital and will be essentially applied through wireless public data network The medical information transmit system is utilized by wireless close range network It would transmit the obtained organism signal wirelessly from the personal device to the main center system in the hospital. Remote telemetry system is embodied by utilizing wireless media access protocol. The protocol is embodied by grafting CSMA/CA(Carrier Sense Multiple Access with Collision Avoidance) protocol falling mode which is standards from IEEE 802.11. Among the house care telemetry system which could measure blood pressure, pulsation, electrocardiogram, SpO2 the study embodies the ECC(electrocardiograph) measure part. It within the ECC function into the movable device and add 900㎒ band wireless public data interface. Then the aged, the patients even anyone in the house could obtain ECG and keep, record the data. It would be essential to control those who had a health-examination heart diseases or more complicated heart diseases and to observe the latent heart disease patient continuously. To embody the medical information transmit system which is based on wireless network. It would transmit the ECG data among the organism signal data which would be utilized by wireless network modem and NCL(Native Control Language) protocol to contact through wireless network Through the SCR(Standard Context Routing) protocol in the network it will be connected to the wired host computer. The computer will check the recorded individual information and the obtained ECC data then send the correspond examination to the movable device. The study suggests the medical transmit system model utilized by the wireless public data network.

• Journal of KIISE:Information Networking
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• v.33 no.1
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• pp.59-75
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• 2006

In this paper, we propose a congestion control scheme to control the congestion due to the mobility of ubiquitous devices on ubiquitous computing environment. Especially, this congestion control scheme provides a reverse congestion avoidance state which can classify between packet error by features of wireless network and packet dropping by congestion. Also, it provides a slow stop state which can minimize bandwidth waste due to congestion control. The proposed congestion control scheme controls more adaptive than existing congestion control schemes. The proposed congestion control scheme is designed based on DCCP(Datagram Congestion Control Protocol) being proposed by IETF(Internet Engineering Task Force) and implemented on the Linux kernel. In simulation results, the proposed congestion control scheme provides good bandwidth throughput in wireless network as well as in wired network.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.519-522
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• 2005

Decentralized Dynamic Surface Control(DDSC) for a class of nonlinear system interconnected via sensor network is presented in this paper. While a centralized design approach of DSC was developed in [1], the decentralized approach to deal with complex large-scale systems is proposed under the assumption that interconnected functions among subsystems are known via sensor network. As shown in [2], the separation principle for DDSC will allow us to design an estimation filter independently. Furthermore, the theoretical results are used to design and simulate an active vibration isolator under the assumption that many embedded sensors are distributed and communicate each other via wireless communication.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.1
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• pp.60-65
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• 2006

Recently, various ubiquitous networking services are developed and implemented for easy living. In general, new ubiquitous networking services require the new infrastructure including equipments and devices. However, it is difficult to replace existing infrastructure and devices with new ones in the home or office because of cost and maintenance problems. In this paper, we developed small-size web based RF wireless communication systems for sensor network applications. The designed RF systems are implemented using commercial system on a chip (SoC) on existing infrastructure and devices. The developed systems are tested for light control and temperature sensing and they are applied to sensor network training courses for students and engineer as well as various practical applications.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.2
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• pp.93-100
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• 2014

IEEE 802.11 Wireless LAN Medium Access Control(MAC) supports two transmission methods, a DCF basic and a RTS/CTS in contention-based access. Even though the RTS/CTS method has been optionally introduced to solve the hidden terminal problem, it is able to produce better performance in some network environments than the basic transmission method. In this paper, the collision probability of wireless channel is mathematically analyzed and applied to measure network throughput using real transmission parameters so that a reference value between throughputs of two methods is obtained. We also confirmed that control signal rates affect overall network throughput and evaluated network throughputs considering collision probability, number of stations, and contention window size of Backoff between two methods respectively.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4367-4386
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• 2015

The concept of Internet of Things (IoT) has shed new light on WSN technologies. MAC protocol issues improving the network performance are important in WSNs because of the increase in demand for various applications to secure spectrum resources. Cognitive radio (CR) technology is regarded as a solution to the problems in this future wireless network. In recent years, energy efficiency has become an issue in CR networks. However, few relevant studies have been conducted. In this paper, an energy-efficient non-overlapping channel MAC (ENC-MAC) for CR-enabled sensor networks (CRSNs) is proposed. Applying the dedicated control channel approach, ENC-MAC allows the SUs to utilize channels in a non-overlapping manner, and thus spectrum efficiency is improved. Moreover, the cooperative spectrum sensing that allows an SU to use only two minislots in the sensing phase is addressed to en-hance energy efficiency. In addition, an analytical model for evaluating the performance, such as saturation throughput, average packet delay, and network lifetime, is developed. It is shown in our results that ENC-MAC remarkably outperforms existing MAC protocols.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.1
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• pp.31-38
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• 2012

Next generation cellular applications and smart phone usage generate very heavy wireless data traffic. It becomes ineluctable for mobile network operators to have multiple core network entities such as Serving Gateway and Packet Data Network Gateway in 4G-LTE to share this high traffic generated. A typical configuration consists of multiple serving gateways behind a load-balancer which would determine which serving gateway would service a end-users'request. Such hardware is expensive, has a rigid policy set, and is a single point of failure. Another perspective of today's increasingly high data traffic is that besides it is being widely accepted that the high bandwidth L TE provides is creating bottlenecks for service providers by the increasing user bandwidth demands without creating any corresponding revenue improvements, a hidden problem that is also passively advancing on the newly emerging 4G-LTE that may need more immediate attention is the network signaling traffic, also known as the control-plane traffic that is generated by the applications developed for smartphones and tablets. With this as starting point, in this paper, we propose a solution, by a new approach considering OpenFlow switch connected to a controller, which gains flexibility in policy, costs less, and has the potential to be more robust to failure with future generations of switches. This also solves the problem of scaling the control-plane traffic that is imperative to preserve revenue and ensure customer satisfaction. Thus, with the proposed architecture with OpenFlow, mobile network operators could manipulate the traffic generated by the control-plane signaling separated from the data-plane, besides also reducing the cost in installing multiple core-network entities.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.465-468
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• 2007

An intelligent home network system using low-power and low-cost sensor nodes was designed and implemented. In Intelligent Home Network System, active home appliances control is composed of RSSI (Received Signal Strength Indicator) based user indoor location tracking, dynamic multi-hop routing, and learning integration remote-control. Through the remote-control learning, home appliances can be controlled in wireless network environment. User location information for intelligent service is calculated using RSSI based Triangle measurement method, and then the received location information is passed to Smoothing Algorithm to reduce error rate. In order to service Intelligent Home Network, moreover, the sensor node is designed to be held by user. The gathered user data is transmitted through dynamic multi-hop routing to server, and real-time user location & environment information are displayed on monitoring program.