• Journal of IKEEE
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• v.21 no.2
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• pp.115-122
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• 2017

In vehicular safety service, every vehicle broadcasts Basic Safety Message (BSM) periodically to inform neighbor vehicles of host vehicle information. However, this can cause network congestion in a region that is crowded with vehicles resulting in a reduction in the message delivery ratio and an increase in the end-to-end delay. Therefore, it could destabilize the vehicular safety service system. In this paper, in order to improve the congestion control and to consider the hidden node problem, we propose a congestion control scheme using entire network congestion level estimation combined with transmission power control, data rate control and time slot based transmission control algorithm. The performance of this scheme is evaluated using a Qualnet network simulator. The simulation result shows that our scheme mitigates network congestion in heavy traffic cases and enhances network capacity in light traffic cases, so that packet error rate is perfectly within 10% and entire network load level is maintained within 60~70%. Thus, it can be concluded that the proposed congestion control scheme has quite good performance.

• ETRI Journal
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• v.24 no.6
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• pp.465-468
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• 2002

Ethernet passive optical networks (PONs) are an emerging access network technology that provides a low-cost method of deploying optical access lines between a carrier's central office and a customer site. In this paper, we propose a new algorithm of dynamic bandwidth allocation for multimedia services over Ethernet PONs. To implement the suggested dynamic bandwidth allocation algorithm, we present control message formats that handle classified bandwidths in a multi-point control protocol of Ethernet PONs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11B
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• pp.1607-1617
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• 2010

In this paper we propose MA-CBRP, mesh adaptive algorithm for wireless mesh networks. MA-CBRP is a hybrid algorithm based on ad-hoc CBRP protocol. In MA-CBRP, the mesh router periodically sends the ANN message as like Hello-message in CBRP. ANN message allows to all clients periodically store a route towards the mesh-router and renewal information in their routing cache. While CBRP periodically reply Hello-message, MA-CBRP does not reply to achieve less overhead. After receiving ANN message, mesh client send JOIN message to mesh router when the route towards mesh router changed. at the same time Register the entry to mesh router, it can achieve to reduce overhead of control the route and shorten the time to find route. consequently, MA-CBRP shows 7% reduced overhead and shortened time to find route than CBRP with regardless of clients number.

• The Transactions of the Korea Information Processing Society
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• v.4 no.7
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• pp.1797-1803
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• 1997

Message handling function of the SS7(Signaling System N0.7) provides signaling traffic routing capabilities to transfer the signaling traffic to the destination nodes in the signaling network. This message handling function should be handled without any transfer delay for real time processing of large amount of signaling traffic for data communication service, and visual information service. In this paper, we suggest two routing algorithms working on the distributed message handling processors which were specially designed for message handling function. The one is an internal distributing algorithm for equal distribution of signaling traffic among the distributed message handling processors and the other is a distributing algorithm for distribution of signaling traffic in the multiple signaling routes. Both of algorithms are using signaling link selection codes labled in each signaling messages. It is shown that the suggested algorithms are very efficient for routing signaling traffic at the fault condition of signaling routes and the restoration of unavailable signaling routes.

• Transactions of The Korea Fluid Power Systems Society
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• v.8 no.4
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• pp.17-23
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• 2011

Proportional control solenoid is a type of modulating valve that can continuously control the valve position with magnetic force of solenoid. Recent microcontroller based digital servocontroller for proportional valve is being developed toward the smart valve with additional features such as enhanced control algorithm for finer process and intelligent on-board diagnosis for maintenance. In this paper, development of servocontroller network control with CAN bus which is free from problems of security and network traffic jam is presented. Design of network control system includes modes of communication between master and slave, assignment of 29bit message identifier and message objects, transaction of communication sequence, etc. Monitoring function and control experiments for remote valve through CAN network prove the extended function of smart valve control system.

• Journal of Digital Convergence
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• v.12 no.9
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• pp.209-217
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• 2014

As an idea of healing or fatigue recovery, a desire for massage therapy has increased for modern people who complain of pain such as knotted muscles or shoulder discomfort due to fatigue accumulation and stress. To resolve this, although a massage chair has been developed, it does not provide the most efficient massage as it is not suitable for Korean body types. In this paper, this research analyzed massage, assembly, massage intensity, Korean body types and functions of the massage for maximized efficiency to design critical functions. Also, we implemented the action control and algorithm of the massage chair for localization.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.8
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• pp.1965-1972
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• 2015

The Missile Flight Test Launch Control System is to operate in conjunction with the Fire Control System during flight test to guided weapons. Also, this is a system for the test control and situation monitoring depending on the type of guided weapons and testing purposes. Message structure, communication protocols, such as data types for interworking with the fire control system and the Missile Flight Test Launch Control System are defined in the Launch Control ICD(Interface Control Document). ICD are composed differently of each guided weapons system and each test object. Previously, in order to interwork with the Fire Control System, the interlocking software was developed, which had a variety of problems. Therefore, we developed a new parsing algorithm in order to recognize the variety of Launch Control ICD and verified that the algorithm operates normally by checking transmitting and receiving various message in conjunction with the fire control system.

• Journal of the Korean Institute of Intelligent Systems
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• v.27 no.1
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• pp.65-71
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• 2017

Since existing Internet of Things(IoT) is vulnerable, it may cause property damage due to the information leakage. Especially, the smart door lock system built on the IoT can cause more damage. To solve these problems, this paper classify the data generated by the sensor according to the condition and send an alarm message to the user's smartphone through Google Cloud Message (GCM). We made it possible to check the images in real time through the smartphone application and control the door lock using the TCP / IP protocol. Also, we applied OTP-Based Matrix SEED algorithm to door lock system to improve security.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.642-649
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• 2018

The Modbus protocol is the most widely used protocol for connecting multiple slave control units (SCUs) in the master control unit. However, the Modbus protocol does not identify which SCU response message corresponds to the service request message. Therefore, when using the Modbus protocol, one service request message can be transmitted after processing the previous message. In this paper, we propose a Modbus application protocol with an index code and a service code to solve the problem. As a result of experimentation, it is possible to transmit the next service request message without processing the previous service request message. And when a communications error occurs, it is possible to identify what type of error occurred using an error detection algorithm. Also, with simultaneous multiple service requests, the proposed protocol can improve processing time by about 66.2%, compared to the original Modbus protocol.

• Journal of applied mathematics & informatics
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• v.12 no.1_2
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• pp.395-408
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• 2003

Common Channel Signaling(CCS) networks need special controls to avoid overload of signaling networks and degradation of call process-ing rate, since they play an important role of controlling communication transfer networks. Congestion control and flow control mechanisms are well described in ITU-T recommendation on Signaling System No.7(SS7). For the practical provisions, however, we need an analysis on the relation among service objects, system requirements and implementation of congestion control algorithms. SS7 provides several options for controlling link congestion in CCS networks. In this paper we give a general queueing model of congestion control algorithm which covers both the international and national options. From the queuing model, we obtain the performance parameters such as throughput, message loss rate and mean delay for the international option. To show the performance of the algorithm, some numerical results are also given.