• Journal of Astronomy and Space Sciences
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• v.25 no.4
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• pp.459-470
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• 2008

DATS which is one of three subsystems of IDACS is responsible to receive Sensor Data, LRIT and HRIT in L-Band and transmit LRIT and HRIT in S-Band from/to COMS satellite. This paper shows detailed test procedures used to verify the performance and functionality of DATS after its implementation was completely finished. As a part of efforts to verify key DATS performance, G/T and EIRP were measured by using solar flux density as radio source. Regarding the verification of DATS functionality, RF loop-back test was conducted to validate if there is no BER degradation excepting MODEM/BB implementation loss occurred in the integrated DATS. Integrated with 13m antenna, DATS successfully restored image from received MTSAT-1R broadcasting data, LRIT and HRIT, of which frequencies are all L-Band. S-Band transmission was also verified through test antenna placed away from 13m antenna by measuring real LRIT and HRIT spectrum in S-Band. From those test results, DATS is determined to be fully ready to communicate with COMS in L-Band and S-Band.

• Journal of Advanced Navigation Technology
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• v.19 no.3
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• pp.217-223
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• 2015

This paper describes the design and implementation of a network system for UAV for multiple clients that enables long-range operation based on a commercial mobile network. A prototype data modem is developed with a commercial embedded M2M module in order to provide an access to the mobile network. A central server with a database is constructed to record all of real-time flight and video data and communicate with a ground control system. A GCS is developed for the central control, the single UAV and the smart phone version to be used for different purposes. Performance tests were progressed for data delay, video frame rate and state of clients. Flight tests were also performed to verify the reliability of the modem with respect to altitude.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.1
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• pp.148-156
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• 2007

This paper explains stocker system that is operated in the long distance and linear area. The power system of stocker system uses Contactless Power Supply(CPS) to reduce problems of particle generation. The circuit configuration of CPS is simplified than the conventional ones, and the prototype is designed for commercial product. To transfer output data(information) from crane(secondary vehicle system) of the CPS to Primary system optical modem and TMS320F243(DSP, TI) are used between primary and secondary. power system are used, and the output voltage is controlled by operating frequency modulation. This paper is applied to stocker system controlled as one to one communication between the moving part(secondary system) and fixed part(primary system) of crane using optical modem. The study makes one to multi communication between fixed part and moving part for the purpose of multi crane operation of stocker system and must be done in the future.

• Journal of Advanced Navigation Technology
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• v.12 no.2
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• pp.91-99
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• 2008

In this paper, we implemented an wireless remote control and monitoring system by using Globalstar satellite modem. This system is composed of the data terminal equipment of Globalstar data communication system using microcontroller, C8051F023, and WGIS(Web-based GIS) user program. We tested the wireless remote control and monitoring system with data terminal equipment and user program how to work properly, and verified that the user could confirm the data from the data terminal equipment, which can provide the status of input/output devices and the information of location with the main and control dialog by GIS(Geographic Information System) program. For data communication of between data terminal equipment and user program, we programed PPP and TCP/IP protocol to communicate with each other. Some GIS tools used in this program are ArcView and MapObject from ESRI to offer various visual mapping information to the user.

• Journal of Advanced Navigation Technology
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• v.24 no.2
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• pp.67-72
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• 2020

Satellite communication is not used by many people like mobile communication, but it is a necessary technology for public service and communication services, such as providing the Internet in military, disaster, remote education and medical services, island areas, and infrastructure vulnerable areas. However, on ships and aircraft, mobile communications requiring base stations are either unavailable or restricted in their use. In this paper, we used a Raspberry Pi board as the terminal device to communicate network through satellite modem and PPP protocol, and implemented two-way data link using the text message of the modem to connect to the Thuraya geo-stationary orbit network. In addition, I/O devices were connected to the controller of the terminal equipment to design and implement an IoT device system for ships that can remotely access the system under control and control I/Os and transmit measured data through various sensors.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.5A
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• pp.267-275
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• 2003

In UMTS terminal modem uses 3 step search procedure for initial cell search, which comprises 1) slot synchronization, 2) code group identification and frame synchronization, and 3) scrambling-code identification. The performance of initial cell search procedure depends on search parameters like observation time and threshold. The purpose of this paper is to get the optimal observation time and threshold of each step for minimum mean acquisition time. In this paper we induce mean detection time of each step and mean acquisition timefrom the model of 3 step search procedure using state diagram. Also we propose initial cell search algorithm which utilize window search method against initial oscillator error, and select an appropriate observation time and threshold of each step by the analysis of simulation and induced result. It is shown that the mean acquisition time in multipath fading channel can be shorter than 500ms by using the determined observation time and threshold of each step.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.6
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• pp.1200-1207
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• 2015

A gateway buoy system connects a underwater network to a terrestrial network, which enables to efficiently monitor the underwater network on a land station. In this paper, we introduce an implemented gateway buoy system which relays gathered data from multiple underwater nodes to a land station in a real time. The gateway buoy hardware system is composed of a underwater acoustic modem system, a radio frequency modem system, and a gateway operating system. in additional, we have implemented a land operating program and a land monitoring program for gateway system and states of underwater network, respectively. We also perform real-sea experiments to verify the performance of the gateway buoy system which real-time monitors underwater network states and gateway system states.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.11C
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• pp.1102-1110
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• 2007

In this paper, we design the FPGA (Field-Programmable Gate Array) of the CAMB (Constant-Amplitude Multi-code Biorthogonal) modulation, and implement the SoC (System on Chip). The ASIC (Application Specific Integrated Circuit) chip is be implemented through targeting and board test. This 12Mbps modem SoC includes the ARM (Advanced RISC Machine)7TDMI, 64Kbyte SRAM(Static Random Access Memory) and ADC (Analog to Digital Converter)/DAC (Digital to Analog Converter) for flexible applications. Additionally, the modem SoC can support the variable communication interfaces such as the 16-bits PCMCIA (Personal Computer Memory Card International Association), USB (Universal Serial Bus) 1.1, and 16C550 Compatible UART (Universal Asynchronous Receiver/Transmitter).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.9B
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• pp.822-831
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• 2008

This paper examines the theoretical and empirical technology diffusion processes to understand the Korean success in the internet access service markets. In order to do this, first, we propose an integrated demand diffusion model in terms of competition of inter-and intra-technologies and market structure as represented by the number of operators in the market. Second, by using the proposed model, we analyze the dynamic diffusion processes of Korean internet access services such as Narrow-band technology including Dial modem vs. Broad-band technology including ISDN, xDSL and Cable modem. The competition of inter-and intra-technologies as well as the extent of market competition has made a positive effect on the diffusion patterns of internet access demand. And also we propose, based on the proposed model and its empirical results, several implications for diffusion strategies and policies in the future of ICT market in Korea.

• Journal of architectural history
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• v.11 no.2 s.30
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• pp.23-35
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• 2002

Even though there have been greate changes in the types and contents of the housing plan in Korea since the Modem age, it seems that the identity of traditional dwelling culture is still remains within it. The purpose of this study is to examine the characteristics and features in the development of the 'Public Standard' Housing Unit Plan by comparing the differences and similarities in unit plans in housings built on Japanese occupation period and those built after the period. From the study, we can conclude as follows: 1. The public standard housing unit plans on both periods have shown the common features in the composition of their physical forms in the way that the front-row area still remains the traditional housing culture and the rear-row area reflects the desires of the modem lives. The structure of the dual-row unit plan appeared in the public standard housing plan was caused by the cultural acculturation in Japanese occupation period. 2. The public standard housing unit plans, however, show the differences in the contents and meaning in units plans with the them of the Japanese housing because of the cultural differences. These differences took placed autonomously through the change of housing plans in the modern time, and have the common features such that 1) the changes in the Maru-centered plan type differ in composition from the inner-corridor plan type used Japanese housing, and 2) the composition of the open-inner spaces in the double-row housing plan reflects the single-row outer open space In the traditional housing. All of these cultural progresses in the public standard housing unit plans was took place as the result of the inner-oriented and notional circulations derived from the modernity. However, the transformed unit plans still contains the identity derived from the variation of the traditional Korean building elements such as Maru and Ondol. In other words, those are the Maru-centered and composed housing plans with juxtaposition of the inner block and the outer block. As the conclusion, though the public standard dwelling unit plan has the similarity in the physical form, it is different in the cultural Identity and meaning from the public standard plans before the independence from the Japan occupation.