• Journal of Korea Society of Digital Industry and Information Management
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• v.4 no.3
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• pp.69-75
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• 2008

The objective of this paper is to increase the performance by selecting the optimal value in outputs of two algorithms that are Generlized-Lagrange and LMS(Least Mean Square). This paper presents superior performance by mixed two of conventional algorithm arbitrary. Based on the analysis from various simulation, it is observed that proposed method is better performance in terms of practical WLL(Wireless Local Loop) environment.

• Journal of the Korea Safety Management & Science
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• v.26 no.2
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• pp.55-64
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• 2024

As the distribution of vehicles and logistics increases due to the development of human civilization and the increase in population, various roads play an important role in domestic traffic and transportation. However, the recent emergence of large cities and new cities is causing traffic problems, and the increase in roads is inevitable for the smooth distribution of vehicles and logistics. In Korea, mountainous regions occupy 70% of the country, so tunnels are used to open roads. Without this, it is difficult to open the road. Currently, there are 3,720tunnels (as of December 31, 2023) installed on high-speed national highways, general national highways, and local roads nationwide, with a length of 2.499 and increasing every year. Accordingly, fire accidents in tunnels will also increase, and due to the nature of tunnel fire accidents, there is a high probability that they will escalate into large-scale disasters, resulting in casualties and property damage, as well as significant social losses due to the disruption of logistics transportation, etc. As the possibility of potential hazards is increasing, the purpose of this study is to build a safe and efficient tunnel system by optimizing maintenance and management for fire and disaster accidents in tunnels.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.4
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• pp.483-488
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• 2015

This paper implements a long-term monitoring system (LMS) for ship's engine performance analysis (SEPA) based on the web, for the purpose of the communication speed and engine maintenance. This system is composed of a simulator, monitoring module with a multi channel A/D converter, monitoring computer, network attached storage (NAS), RS485 serial and wireless internet communication system. The existing products monitor the information transmitted from pressure sensors installed in the upper parts of each of engines in the local or web computer, but have a delay in the communication speed and errors in long-term monitoring due to the large volume of sampling pressure data. To improve these problems, the monitoring computer saves the sampling pressure data received from the pressure sensors in NAS, monitors the long-term sampling data generated by the sectional down sampling method on a local computer, and transmits them to the web for long-term monitoring. Because this method has one tenth of the original sampling data, it will use memory with small capacity, save communication cost, monitor the long-term sampling data for 30 days, and as a result, make a great contribution to engine maintenance.

• Journal of Advanced Navigation Technology
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• v.20 no.3
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• pp.232-237
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• 2016

As a possible standardization of wireless local area network (WLAN), IEEE 802.11 LRLP is under discussion in order to support long range and low power (LRLP) communication for internet of things (IoT) including drones and many other IoT devices. In this paper, an efficient adaptive resource unit allocation scheme for uplink multiuser transmission in IEEE 802.11 LRLP networks is proposed. In the proposed scheme, which adopts OFDMA random access based transmission scheme of IEEE 802.11ax, in order to enhance the efficiency of the slotted OFDMA random access, access point (AP) traces the history of the sizes of successfully transmitted uplink data, and adjusts the sizes of resource units for the next uplink multiuser transmission adaptively. Our simulation results corroborate that the proposed scheme significantly improves the system throughput.

• Convergence Security Journal
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• v.13 no.4
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• pp.11-17
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• 2013

All u-Health system has security vulnerabilities. This vulnerability locally(local) or network(network) is on the potential risk. Smart environment of health information technology, Ad-hoc networking, wireless communication environments, u-health are major factor to increase the security vulnerability. u-health care information systems user terminal domain interval, interval public network infrastructure, networking section, the intranet are divided into sections. Health information systems by separating domain specific reason to assess vulnerability vulnerability countermeasure for each domain are different. u-Healthcare System 5 layers of security risk assessment system for domain-specific security vulnerability diagnosis system designed to take the security measures are needed. If you use this proposed model that has been conducted so far vaguely USN-based health information network security vulnerabilities diagnostic measures can be done more systematically provide a model.

• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1315-1318
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• 2003

Wastewater treatment processes are usually located in the outskirts of cities. But these processes should be dealt with continuous maintenance by expert operators. Therefore, in this paper, unmaned and automated control system is designed for the SBR(Sequencing Batch Reactor) plant. This plant is constructed in Gimhae city. Networks and wireless modules are employed for the data transmission. A local controller is in the SBR plant as a client and a monitoring system is located in the other place as a server. Remote control and monitoring system are constructed at the laboratory of ours. Measured data from plant sensors are translated to the remote site using communication modules, and then the data could be displayed and analyzed by means of remote monitoring and control systems.

• Journal of Korea Multimedia Society
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• v.20 no.4
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• pp.649-659
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• 2017

Typically, a smart car is equipped with access to the Internet and a wireless local area network. Moreover, a smart car is equipped with a global positioning system (GPS) based navigation system that presents a map to a user for recommending the shortest path to a desired destination. This paper presents the design and implementation of a real-time shortest path search system for directed and dynamic roads. Herein, we attempt to simulate real-world road environments, while considering changes in the ratio of directed roads and in road conditions, such as traffic accidents and congestions. Further, we analyze the effect of the ratio of directed roads and road conditions on the communication cost between the server and vehicles and the arrival times of vehicles. In this study, we compare and analyze distance-based shortest path algorithms and driving time-based shortest path algorithms while varying the number of vehicles to search for the shortest path, road conditions, and ratio of directed roads.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.11
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• pp.2497-2506
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• 2010

Smart power grid is targeting to improve grid operation by integrating existing power IT technologies in the jeju smart grid field test. Real-time two-way communication and interoperability in power grid are essential to smart power grid. Adopting smart grid will increase security vulnerabilities in power grid by increasing the number of wireless sensors and the chances of the external exposure of communication networks. In addition, hackers can cause chaos in the power grid system with eavesdropping and forgery attacks in communication networks. Smart power grid is one of the most important systems in deploying smart grid, and it is important to design security system systematically since smart grid can be seriously damaged when problem occurs. In this paper, local and global smart grid security standard and security vulnerabilities in power grid are reviewed, and 2 level smart grid service model is proposed.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.1 s.12
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• pp.1-12
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• 2007

The objective of Bus Information System developed as a part of the ITS, provides the operation information of buses to passengers and managers. The system uses roadside antennas (reading electronic tags on board buses) to enable wireless communication each other and radio data communication to deliver information about buses and their locations. This information is used to estimate the arrival time of the bus which will be shown on the bus stop message board or via internet. Bus Information System or Bus Management System (BMS) is going ahead and set up in many local governments, and recently quality improvement of the BIS is considered as a very important element in expanding of business or management. Therefore this research wished to contribute rationalization of the system by maintaining optimum quality. An gang was chosen to apply overall quality control process and will be evaluated in terns of its propriety and performance. This study has led the improvement of service and promote the use of public transits, which is the best way to solve the city traffic problem by effective management of public transits.

• Journal of Advanced Navigation Technology
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• v.14 no.5
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• pp.684-690
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• 2010

Recently, the NG(Next Generation) system is studied for supporting convergence of various services and multi mode of single terminal. And a demand of user for taking the various services is getting increased, for supporting these services, many systems being able to transmit a large message have been appeared. In the NG system, it has to be supporting the CDMA and WCDMA besides the tele communication systems using OFDM method with single terminal An intergrated system can be improved with adopting of SoC technique. For adopting SoC technique on the intergrated terminal, we have to solve the non linear problem of HPA(High Power Amplifier). Nonlinear characteristic of HPA distorts both amplitude and phase of transmit signal, this distortion cause deep adjacent channel interference. We adopt a polynomial pre-distortion technique for this problem. In this paper, a noble modem design for NG mobile communication service and a method using polynomial pre-distorter with PAPR technique for counterbalancing nonlinear characteristic of the HPA are proposed.