• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.563-564
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• 2006

This study is for implementation of PC based Motor fault diagnosis system. By using harmonics and current signals of the motor, this system diagnoses the motor condition by accumulated harmonic contribution rate. In this proposed system that was composed of 5 parts. A sensor, connection box, evaluation board, device server, and main computer are those. There were two types of sensor, one was harmonic sensor the other was current sensors. The signal was acquired by sensor, and transferred to evaluation board. Second one is connection box. Because the output type of sensor and input type of evaluation board is different, connection box was necessary. Third one was evaluation board. The signal from the sensor was converted to digital signal in evaluation board. And this signal was transferred to device server Fourth one was device solver. Device server transferred the data from evaluation board to main computer. And the last one was other parts controlled by main computer. In main computer, there were communication and diagnosis algorithms. The result was derived by main computer. In the result, there were 12 categories and 5 levels of motor conditions. The proposed system had some advantages comparing with stand alone type commercial motor fault diagnosis system. The first, by using remote access it was easier to get the conditions of motor. The second, there was no need to handle the sensors when users measured the motor signals. By this Property, no one was necessary at motor location site. The third, this system was less restricted by times and places than commercial stand alone type diagnosis system. Therefore users can operate this system only using the main computer. Once the sensors are installed at the motor, users doesn't need to move to check up the condition of motors. Moreover, if there is ethernet hub, many motors can be not only diagnosed at once but also decreased its cost.

• 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.

• Proceedings of the KSRS Conference
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• v.1
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• pp.467-470
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• 2006

Geostationary Ocean Color Imager (GOCI) onboard its Communication Ocean and Meteorological Satellite (COMS) is scheduled for launch in 2008. GOCI includes the eight visible-to-near-infrared (NIR) bands, 0.5km pixel resolution, and a coverage region of 2500 ${\times}$ 2500km centered at 36N and 130E. GOCI has had the scope of its objectives broadened to understand the role of the oceans and ocean productivity in the climate system, biogeochemical variables, geological and biological response to physical dynamics and to detect and monitor toxic algal blooms of notable extension through observations of ocean color. To achieve these mission objectives, it is necessary to develop an atmospheric correction technique which is capable of delivering geophysical products, particularly for highly turbid coastal regions that are often dominated by strongly absorbing aerosols from the adjacent continental/desert areas. In this paper, we present a more realistic and cost-effective atmospheric correction method which takes into account the contribution of NIR radiances and include specialized models for strongly absorbing aerosols. This method was tested extensively on SeaWiFS ocean color imagery acquired over the Northwest Pacific waters. While the standard SeaWiFS atmospheric correction algorithm showed a pronounced overcorrection in the violet/blue or a complete failure in the presence of strongly absorbing aerosols (Asian dust or Yellow dust) over these regions, the new method was able to retrieve the water-leaving radiance and chlorophyll concentrations that were consistent with the in-situ observations. Such comparison demonstrated the efficiency of the new method in terms of removing the effects of highly absorbing aerosols and improving the accuracy of water-leaving radiance and chlorophyll retrievals with SeaWiFS imagery.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1048-1053
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• 2005

This paper presents design and integration of the ROBHAZ-DT3, which is a newly developed mobile robot system with chained double-track mechanisms. A passive adaptation mechanism equipped between the front and rear body enables the ROBHAZ-DT3 to have good adaptability to uneven terrains including stairs. The passive adaptation mechanism reduces energy consumption when moving on uneven terrain as well as its simplicity in design and remote control, since no actuator is necessary for adaptation. Based on this novel mobile platform, a rescue version of the ROBHAZ-DT3 with appropriate sensors and a semi-autonomous mapping and localization algorithm is developed to participate in the RoboCup2004 US-Open: Urban Search and Rescue Competition. From the various experiments in the realistic rescue arena, we can verify that the ROBHAZ-DT3 is reliable in traveling rugged terrain and the proposed mapping and localization algorithm are effective in the unstructured environment with uneven ground. The another application is an military robot for an EOD(Explosive Ordnance Disposal) and reconnaissance mission. The military version of the ROBHAZ-DT3 with a water disrupter, a thermal scope and a long distance wireless communication device is developed and sent to the area of military tactics in Iraq. Consequently, the feasibility of the military version of ROBHAZ-DT3 is verified.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12B
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• pp.2320-2334
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• 1999

In this paper, we propose multiple IS-MMBS service schemes for very low power and micro-size RMIMS (radio-interfaced micro information monitoring system) terminals. In MMBS service area, when new arrival RMIMS terminals have real-time traffic characteristic or large traffic bandwidth, only single IS-MMBS service scheme can not guarantee RMIMS terminal's QoS(quality of service) such as buffer overflow or packet loss. In this case, the proposed multiple IS-MMBS service schemes can be effectively used for QoS service of RMIMS terminal. According to clustering method of RMIMS terminals and MMBS segment method, the proposed schemes can be divided into terminal segment method, region segment method, application based segment method, traffic type based segment method, overlapping segment method and hybrid segment method

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12B
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• pp.2298-2319
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• 1999

In this paper, we propose a new moving mobile base station (MMBS) scheme for very low power and micro-size RMIMS (radio-interfaced micro information monitoring system) terminals. RMIMS terminals can be used in various application service areas such as pollution monitoring, environment surveillance, traffic monitoring, emergency monitoring (e.g., building, bridge, railroad breakdown), security monitoring (e.g., theft, alarm) and military application. For these applications based on wireless transmission technologies, sensor type RMIMS terminals must satisfy low cost and low power design (e.g., solar power, life limited battery) requirement. In RMIMS terminal design, this low power requirement limits transmission range of uplink or reverse link and means small cell size. Also these applications using RMIMS terminals may have a little bit non real-time traffic characteristic and low scattering density in service area.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.8
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• pp.1187-1193
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• 2002

There are POP3(Post Office Progocol 3) and IMAP4(Internet Message Access Protocol 4) for E-Mail service of wire Internet For mobile e-mail service that use wireless Internet, must use exclusive use mobile e-mail server in the case of POP3 e-mail or flow e-mail conversion and because e-mail is kept in sever side with remote file server in case of IMAP4 mail that is used by Web-Mail, utilization of mobile e-mail service is difficult by mobile client who there is no IMAP4 rules. This thesis embodying e-mail extraction engine for mobile that do to design markup language converter of XML base, and use Web-Mail of recently been generalizing IMAP4 base in mobile, presented mobile e-mail service method to do so that can use Web-Mail that is based on IMAP4 as well as POP3 mail service in mobile environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.205-214
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• 2017

In this paper, we proposed an iris-based authentication for smart healthcare service in secure telemedicine system. The medical and healthcare information's are very important data in telemedicine system from privacy information. thus, the proposed system provides a secure and convenient authentication method than the traditional ID/PW authentication method to a telemedicine system for age-related chronic diseases. When considering the peculiarities of the use of age-related chronic diseases convenience and healthcare environments, the proposed approach is difficult to secure than traditional ID/PW authentication method with the appropriate means to easily change when stolen or lost to others. In addition, the telemedicine system for the smart healthcare services is one of the types of privacy sensitive medical and health data. it is very important security needs in telemedicine system. Thus we protocol are offer high confidentiality and integrity than existing ID/PW method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.61-71
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• 2017

ARP Spoofing is a basic and core hacking technology for almost all sniffing. It makes change the flow of packets by faking the 2nd layer MAC address. In this paper we suggested an efficient hacking technology for sniffing remote servers in the switched network environment. The suggested 'Faked ARP Reply Unicast Spoofing' makes the bidirectional packets sniffing possible between the client and server, and it makes simplify the procedures for ARP sniffing and hacking program. In this paper we researched the network hacking and implementation technologies based on the suggested ARP spoofing. And we researched various types of servers hacking such as Root ID and PW of Telnet/FTP server, Root ID and PW of MySQL DB server, ID and PW of Web Portal Server, and account information and transaction history of Web Banking Server. And also we researched the implementation techniques of core hacking programs for the ARP Spoofing.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.681-684
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• 2015

Power amplifier is an essential component for transmitting signals to a remote receiver in wireless communication systems. Power amplifier is a non-linear device in general, and the nonlinear distortion becomes severer as the output power increases. The nonlinearity results in spectral regrowth, which leads to adjacent channel interference, and decreases the transmit signal quality. To linearize power amplifiers, many techniques have been developed so far. Among the techniques, digital pre-distortion is known as the most cost and performance effective technique. However, the linearization performance falls down abruptly when the power amplifier operates in its saturation region. This is because of the severe nonlinearity. To relieve this problem, this paper proposes a new adaptive predistortion technique. The proposed technique controls the adaptive algorithm based on the power amplifier input level. Specifically, for small signals, the adaptive predistortion algorithm works normally. On the contrary, for large signals, the adaptive algorithm stops until small signals occur again. By doing this, wrong coefficient update by severe nonlinearity can be avoided. Computer simulation results show that the proposed method can improve the linearization performance compared with the conventional digital predistortion algorithms.