• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.65-67
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• 2006

광통신이 발달하면서 보다 빠른 정보전송을 할 수 있지만 다른 전송매체와 마찬가지로 장거리 전송 시 손실이 발생하고 이러한 문제의 해결책으로 광 증폭기의 필요성이 대두 되었다. 기존의 광신호 증폭기에서는 광 신호를 전기신호 변환한 후 증폭하고 다시 증폭된 전기신호를 광신호로 변환하는 과정과 복잡한 구조는 전송시스템의 병목 문제를 유발하였다. 이러한 문제점을 해결할 수 있는 순수 광신호 증폭시스템인 어븀첨가광섬유증폭기 (EDFA)를 제작하고 EDFA의 이득평탄화를 위하여 이득평탄화 필터로 MLPFG를 제작하여 적용하였다. 제작된 EDFA는 20dB 이상의 신호 증폭을 보였다.

• Journal of Navigation and Port Research
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• v.27 no.6
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• pp.683-691
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• 2003

This exploratory study aims to investigate issues that, according to the Nonaka's theoretical model, are believed to hold significant ramifications on the effectiveness of creating and sharing organizational knowledge among distributed workers. These include changes in accessibility of knowledge with different levels of implicity, and the choice of communication media as a knowledge management channel. Related data were gathered from distributed-workers in Japan through interviews and a survey questionnaire. Data analysis revealed changes in the dynamics of internal and external interactivity, in the accessibility of necessary knowledge, and in the reliance on electronic media for knowledge exchange. The findings' implications are discussed from the perspective of knowledge creation ana sharing, and further suggestions have been made for the direction of future research efforts.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2017.11a
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• pp.132-133
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• 2017

The International Maritime Organization (IMO) has defined e-Navigation for the purpose of providing safe and efficient maritime information and communication services. Currently, a maritime cloud is being developed as a communication infrastructure for e-Navigation services. In this paper, we design the structure of vessel ID importation system which can efficiently register the maritime ID in the maritime cloud environment.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.08a
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• pp.163-166
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• 2004

Integrated Ship-Shore Information System makes use of advanced technology of marine mobile communication and extends the computer network of shipping company to ship. This system conveniently accomplishes the information exchange between company and ship, guarantees navigation safety and improves commercial performance. The framework of integrated ship-shore information system and the analysis of its function are provided in this paper. Meanwhile, the idea based on the specification of J2EE to build this system is put forward and the relevant technology is demonstrated.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.2
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• pp.77-82
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• 2020

IoT devices frequently require input resources to communicate with various sensors or IoT platforms. IoT device wastes a lot of time as idle time or waiting time to check the data of the input resource and use the input resource. In addition, IoT devices use various input resources. We compares and analyzes input idle time and input waiting time generated from hardware serial input resource, software serial input resource, digital port input resource, and analog port input resource using Arduino widely used as IoT device. In order to design the IoT device framework, it is necessary to understand the characteristics of input resources and to design them to minimize unnecessary input idle time and input waiting time. The analog input wait time has a much larger input wait time than the digital input wait time, so it must be designed to receive analog information periodically at the appropriate timing. The characteristics of the input resources analyzed in this way help to design an efficient IoT device.

• Journal of information and communication convergence engineering
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• v.8 no.6
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• pp.671-676
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• 2010

In this paper, an effort has been made to design and develop a meteorological data logger for meteorological purpose. This data logger is proposed to be included various sensor interface that used in weather sensors. Besides, numbers of meteorological process libraries are added into this data logger to make it able to perform as unattended weather monitoring system. Data output of this data logger are also design to support multiple protocol that commonly used in data logger, and several communication devices that commonly used in the market. Each data that logged will be logged together with date and time and able to retrieve via serial port using hyper terminal. It is also configurable via serial port.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.10b
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• pp.29-35
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• 2000

As the increasing demand of the radio wave communication and teh progreessing of communication system, the radio interference of neighbor nations is rising in the improtant matter. This problem is a delicate matter which must be dealt diplomatically with by having a distinct technical basis. For our country, after the radio interference has been occurred in TRS service on the south seashore due to the base stations located at Fukuoka in Japan, the radio interference problem of neighbor nations has risen importantly. In this paper, therefore, we has measured the radio wave that reach from Fukuoka in Japan to Pusan in Korea and also collected dat by real-time.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.211-212
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• 2019

Since nuclear power plant accident has occurred in Fukushima, marine pollution problem has been a hot issue due to discharging of contaminated water This paper deals in the marine environment monitoring sensor system. In this paper, we study on sensor and communication system to observe the various source of maritime pollution in realtime and transmit the measured date to observation center.

• Journal of information and communication convergence engineering
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• v.5 no.1
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• pp.23-28
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• 2007

In this paper, we propose ATM switch structure including AAL type 2 switch which can efficiently transmit low-bit rate data, even if the network has many endpoints. We simulate the architecture of ATM switch fabric that is modeled in computer program and analyze the performance according to offered loads. ATM switch proposed in this paper can support cell switching for all types of AAL cells which consist of AAL type 1, AAL type 2, AAL type 3/4, and AAL type 5 cells. We propose two switch fabric methods; One supports the AAL type 2 cell processing per input port, the other global AAL type 2 cell processing for every input port. The simulation results show that the latter is superior to the former. But the former has a strong point for easy implementation and extensibility. The proposed ATM switch fabric architecture is applicable to mobile communication, narrow band services over ATM network.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.485-489
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• 2006

In last decades, several linearization methods for the AOA measurements have been proposed, for example, Gauss-Newton method and closed-form solution. Gauss-Newton method can achieve high accuracy, but the convergence of the iterative process is not always ensured if the initial guess is not accurate enough. Closed-form solution provides a non-iterative solution and it is less computational. It does not suffer from convergence problem, but estimation error is somewhat larger. This paper proposes a self-tuning weighted least square AOA algorithm that is a modified version of the conventional closed-form solution. In order to estimate the error covariance matrix as a weight, two-step estimation technique is used. Simulation results show that the proposed method has smaller positioning error compared to the existing methods.