• The Journal of Information Systems
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• v.17 no.1
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• pp.155-171
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• 2008

This thesis proposed a method that connecting step motor to image send board which can acquire image to move and remote controlling via streaming image board of PDA(personal digital assistant) based on embedded Linux which is using wireless network There are three embedded Linux system to embody movable image send board. First, though the wireless network a signal of PDA is transmitted to the board which has embedded Linux and a system which is controlled by the expansion I/O port of the board. Second, it's a system streaming realtime image at a PDA which has embedded Linux. The last is a system which controls a process of image board using TCP/IP communication and image send board at PC. These are the system which can use industrial settings and homes. It can also make use of an embodiment method about travelling image robot.

• Journal of Korea Multimedia Society
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• v.17 no.7
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• pp.879-885
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• 2014

This paper designs and implements the 2 plug type standby power control outlet based on IEEE 802.15.4 using Zigbee and IPv6 network in order to reduce the standby power to the user. The standby power control system is consisted of direct power and standby power plug. Also this system can communicate bidirectionally in wireless because built-in wireless communication modules. One gateway is linked with many standby power control outlet in wireless. Each standby power control outlet executes the operation needed in power control independently. Also each standby power control outlet has its own power can be detected in real time independently of the power can be controlled.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1811-1818
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• 2009

This paper is about the research to maintain and enhance the flow of data of the wireless traffic control. Various types of burst traffic that were found at TCP window flow control have been removed or mitigated using the two-way traffic control. Currently, TCP ACK Compression problem appears during the transmission of the wireless communication control channel because the queues are mostly located at the end system. Therefore, in this paper, the periodic bursty characterist of the source IP queue wilt be analyzed to predict the maximum value of queues. And then the prediction tool will be applied to wireless communication traffic control to handle symmetric traffic as to increase the throughput and improve the performance.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.4
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• pp.385-390
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• 2015

Quay cranes are considered core equipment for container terminal operation. However, unmanned operation systems have not as yet been announced due to the technological difficulties of implementation. In this paper, we developed a wireless controller to control a quay crane simulator remotely and conducted its performance test, a first step toward unmanned operation of quay cranes. The communication delay of a developed wireless controller was about 9.4ms on average while that of existing wired controllers was about 5.6ms. The same functions were implemented and tested on a smart phone where the average communication delay was 7.3ms. In addition, to apply the developed system into a real environment, we proposed a network architecture based on IEEE 802.11ac and carried out its performance evaluation. When the distance between two nodes was 50m apart, the throughputs of the TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) were 57Mbps and 189Mbps, respectively. The communication delay of the control data was 9.1ms through the TCP channel. These results reveal the proper working of remote quay crane operation if we adopt the IEEE 802.11ac network.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.3
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• pp.230-234
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• 2007

Generally, huge amounts of data traffic are generated by using broadcasting method to deliver sensing data to a sink node reliably so that it makes a severe network saturation problem resulting in unreliable data transfer. In order to handle this problem, a new congestion control protocol is required for supporting reliable data transfer, minimal use of energy and network resources at the same time in wireless sensor networks. In this paper, it proposes a Protocol to guarantee both a reliable transfer in data accuracy and minimum consumption of energy waste by using Hop-by-Hop sequence number and DSbACK(Delayed and Selective ACK Buffer Condition) scheme. In addition, it proves that reliability and energy efficiency are enhanced by the proposed method with the simulation results performed on TinyOS platform which is a component based built-in OS announced by UC Berkely with the performance comparison of other existing methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10B
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• pp.876-884
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• 2008

In this paper, we propose an asynchronous MAC protocol to minimize energy usage and to maximize data throughput for a wireless sensor network in multi channel environments. Our proposed SPMC-MAC (Slim Preamble Multi-Channel Media Access Control) adopts the preamble sliming mechanism proposed in [6] that takes advantage of the knowledge about the wakeup time of the receiver node. The preamble contains the receiver's ID and a randomly selected channel ID for data communication, and it is transmitted over a dedicated common channel. The power control has the benefit of keeping an appropriate number of nodes with the communication range, resulting in reduced collision and interference. We compare our SPMC-MAC and X-MAC extensively in terms of energy consumption and throughput using mathematical analysis and simulation.

• Journal of Advanced Navigation Technology
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• v.11 no.3
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• pp.233-238
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• 2007

In this paper, a wireless sensor network system was embodied inside the shipping for digital ship. First, the analysis of radio environment inside ship are investigated. As a result, it was confirmed that a wireless sensor network system can be applied inside the ship. Using Shipboard Wireless Sensor Network System based on IEEE 802.15.4 technique, we designed, and made the prototype of Zigbee Node and RFID Reader. We could be sensing on shipboard and testing entrance of crew by using Zigbee Node and RFID Reader. The sensing and exit or entry control data are transmitted a server system through internet that connected Wireless Gateway with AP, so we can monitoring the saved data on shipboard database.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.357-360
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• 2008

Vital sign monitoring system using IEEE 502.IS.4 based wireless sensor network(WSN) is designed and developed on mobile environment and sensor node platform. WSN and CDMA are integrated to create a wide coverage to support various environments like inside and outside. We developed query processor to use selective any devices(ECG, Blood pressure and sugar module) and control of the self-organizing network of sensor nodes in a wireless sensor network. Vital sign from wireless medical any devices are analysed in cell phone first for real time signal analyses and the abnormal vital signs are sent and save to hospital server for detail signal processing. wireless signal traffic in wireless sensor network environment or data communication inside the cell phone is reduced.

• Journal of the Korean Society for Railway
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• v.16 no.6
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• pp.551-557
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• 2013

This research aims to conduct a study on the feasibility of the LTE communication method for developing a dedicated integrated railway wireless network. An empirical analysis was carried out by establishing a dedicated integrated railway wireless network in an approximately 12km section between Illo station and Daebul station on the Honam line. Korean wireless communication methods for railway safety are different depending on each line, which makes it difficult for railway workers to cooperate with. This causes various problems. There is the ever-present risk of accidents due to call disconnection between wireless communication systems, frequency interference from commercial networks, and crosstalk. This study verified the feasibility of the 4th generation communication system, LTE, over the dedicated integrated railway wireless network as a solution for the above mentioned problems. The result shows this communication system exceeded existing performance standards of Europe GSM-R in every test item despite the location constraint of train tracks on the base station establishment.

• The KIPS Transactions:PartC
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• v.9C no.1
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• pp.39-44
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• 2002

In this paper, in order to improve the performance of TCP short traffic application services in wireless Internet environments, the Split-ACKs (SPACK) scheme is proposed. In wireless networks, unlike wired networks, packet losses will occur more often due to high bit error rates. Therefore, each packet loss over wireless lints results in congestion control procedure of TCP being invoked at the source. This causes severe end-to-end Performance degradation of TCP. In this paper, to alleviate the TCP Performance, the SPACK method, split acknowledgement Packets in the base station, is proposed. Using computer simulation, the performance of TCP using SPACK is analysed and shows better performance than traditional TCP Protocol.