• Journal of Advanced Navigation Technology
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• v.14 no.2
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• pp.213-219
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• 2010

Recently, a multi-core system is studied for single terminal's operations on various service networks for mobile systems. Therefore, it is expected that mobile systems capable of supporting WCDMA, MC-CDMA, CDMA and WiBro would be developed. Mobile systems for supporting various service networks is able to be implemented on a single chipset via SoC(System one Chip) technology, thus a noble modem design proper for SoC technology is necessary. For high speed data transmission of 4G mobile communication services, OFDM scheme has to be applied. But, an OFDM signal consists of a number of independently modulated subcarriers, and superposition of these subcarriers cause a problem that can give a large PAPR. In this paper, a noble modem design for 4G mobile communication services and PAPR reduction method for solving the PAPR problem are proposed.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.1
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• pp.113-120
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• 2009

Through the automatic sensing of the environment, USN technology can give the best services. In this work, we have developed an active RFID system and examined its performance. By implementing it into water quality sensors, we constructed a system that can detect diverse indoor/outdoor environment and provide information about the pollution level obtained from the temperature and PH sensors. Our RF system had an internal Print-on-PCB antenna for the miniaturization of the tag. We used a RF transceiver CC2510 chipset of TI company to realize the active RFID function. By using RSSI constants obtained, we performed the evaluation of real time location accuracy with a software written in Labview. Among 10 arbitrary locations, we obtained average measurement errors of 1.69 m in x axis and 1.66 m in y axis. This technology can be applied to logistics, environmental monitoring, prevention of missing children and various applications.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.11
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• pp.2437-2445
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• 2012

This paper presents the efficient measurement method of radio resource by analyzing various medium occupied elements. The medium occupied time consists of 802.11 frames, wireless interference, and protocol waiting time from a wireless node on a current channel. And it is used to performance metric. Existing research is only measured partial occupied elements, and is lack of validation of measurement unit and scalability on various IEEE 802.11 radio. This paper presents the measurement method of classified occupied elements. To achieve this, we modified 802.11n based OpenHAL device driver to collect the register information of wireless chipset, and to analyze receiving frames in an virtual monitor mode. We conclude accurate medium occupied time measurement system from various validation methods.

• Journal of Korea Society of Industrial Information Systems
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• v.8 no.1
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• pp.83-91
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• 2003

High-speed QPSK demodulator has been in important design objective of any wireless communication systems, especially those offering broadband multimedia service. This paper describes all-digital QPSK demodulator for high-speed wireless communications, and its hardware structures are discussed. All-digital QPSK demodulator is mainly composed of symbol time circuit and carrier recovery circuit to estimate timing and phase-offsets. There are various schemes. Among them, we use Gardner algorithm and Decision-Directed carrier recovery algorithm which is most efficient scheme to warrant the fast acquisition and tacking to fabricate FPGA chip. The testing results of the implemented onto CPLD-EPF10K100GC 503-4 chip show demodulation speed is reached up to 2.6[Mbps]. If it is implemented a CPLD chip with speed grade 1, the demodulation speed can be faster by about 5 times. Actually in case of designing by ASIC, its speed my be faster than CPLD by 5 times. Therefore, it is possible to fabricate the all-digital QPSK demodulator chipset with speed of 50[Mbps].

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.3
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• pp.294-301
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• 2020

Man-In-Simulant Test(MIST) provides a test method to evaluate chemical protective equipments such as protective garments, gloves, footwear and gas mask. The MIST chamber is built to control concentration of chemical vapor that has a activity space for two persons. Non-toxic methyl-salicylate(MeS) is used to simulate chemical agent vapor. We carried out to measure inward leakage MeS vapors by using passive adsorbent dosimeter(PAD) which are placed on the skin at specific locations of the body while man is activity according to the standard procedure in MIST chamber. But more time is required for PADs and there is concern of contamination in PADs by recovering after experiment. Therefore detector for measuring in real time is necessary. In order to analyze in real time the contamination of the personal protective equipment inside the chemical environment, we have developed a wireless real-time gas detector. The detector consists of 8 gas-sensors and 1 control-board. The control-board includes a CPU for processing a signal, a power supply unit for biasing the sensor and Bluetooth-chipset for transmission of signals to external PC. All signals from gas-sensors are converted into digital signals simultaneously in the control-board. These digital signals are stored in external PC via Bluetooth wireless communication. The experiment is performed by using protective equipment worn on manikin. The detector is mounted inside protective equipment which is capable of providing a real-time monitoring inward leakage MeS vapor. Developed detector is demonstrated the feasibility as real-time detector for MIST.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.959-962
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• 2009

Recently, a multi-core system is studied for single terminal's operations on various service networks for mobile systems. Therefore, it is expected that mobile systems capable of supporting WCDMA, GSM, and WiBro would be developed. Mobile systems for supporting various service networks is able to be implemented on a single chipset via SoC(System on Chip) technology, thus a noble modem design proper for SoC technology is necessary. As those systems shall be operated at different frequency band with only a single terminal, a problem that a nonlinear characteristic according to the system and its frequency band is occurred. In this paper a noble modem design for multi-core systems is proposed and the nonlinear characteristics for those systems is analysed. The proposed modem design is based on OFDM(Orthogonal Frequency Division Multiplexing) and MC-CDMA scheme. And nonlinear characteristic analysis is done by PSD measurement.

• Journal of the Institute of Convergence Signal Processing
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• v.23 no.2
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• pp.91-96
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• 2022

At the current camera-based technology level, sensor-based basic life pattern recognition technology has to suffer inconvenience to obtain accurate data, and commercial band products are difficult to collect accurate data, and cannot take into account the motive, cause, and psychological effect of behavior. the current situation. In this paper, radar technology for life pattern recognition is a technology that measures the distance, speed, and angle with an object by transmitting a waveform designed to detect nearby people or objects in daily life and processing the reflected received signal. It was designed to supplement issues such as privacy protection in the existing image-based service by applying it. For the implementation of the proposed system, based on TI IWR1642 chip, RF chipset control for 60GHz band millimeter wave FMCW transmission/reception, module development for distance/speed/angle detection, and technology including signal processing software were implemented. It is expected that analysis of individual life patterns will be possible by calculating self-management and behavior sequences by extracting personalized life patterns through quantitative analysis of life patterns as meta-analysis of living information in security and safe guards application.

• 전자공학회논문지 IE
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• v.49 no.1
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• pp.12-17
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• 2012

Fast development of ubiquitous technology prompted the broadening of the related application area. Application of ubiquitous techniques and system into the construction sites may give us many benefits. There are always a lot of hazard situations in construction sites, and the falling is known to have the high accident rate. To prevent the falling, there has been a lot of efforts including safety education and use of safety gears. In this study, we designed, fabricated and tested a system that can monitor the worker's safety and location informations in real time by using the wireless technology of TOA and RSSI. We used ATmegal28 that is popular in the industrial equipments as MCU and NanoPan 5357 module from Nanotron and CC2500 chipset from TI for radio circuits. We also used 3-axis accelerometer and pressure MEMS sensors to obtain the environmental information, and therefore to aquire the informations of the worker's movement and altitude. We used Labview software from National Instrument to monitor and control the system. We developed the system to send the warning alarms to the server operator and the workers when the workers in the danger zone did not wear the safety hook.

• Journal of Biomedical Engineering Research
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• v.18 no.3
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• pp.291-299
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• 1997

As a microimaging device detecting gamma rays emitted from small lesions or tumors during operation, the intraoperative surgical probe has been proposed and is now under development. We have designed a multipurpose portable gamma prove system and evaluated the performance both for the absolute counting purpose of residual radioactivities and for the localizing capability of gamma events using the NaI(Tl) crystal and two types of photomultiplier tubes(PMTs). Counting efficiencies in the range of routine clinical use of radiation dose were measured using the assembly of single channel PMTs and 0.5 inch thick NaI(Tl) crystal of 1 inch diameter. The positioning of gamma events for imaging purpose requires the multiple channel PMTs with appropriate positioning electronics. We have designed a simple and reliable positioning circuit based on the concept of modified Anger. In preliminary experiments using the multiple channel PMT of 3 inch diameter and the dim lighth source, we were able to trace and localize the correct position with reduced positioning error by the use of two multiplier/divider chipset and simplified peripherals. The energy resolutions for the counting gamma probe measured as full width at half maximum(FWHM) for Cs-137, F-18, Tc-99m were 12%, 13%, and 36%, respectively. The spatial resolution for the imaging gamma probe measured as FWHM for green LED was 2.9 mm. The results indicate that the currently developing probe is very promising and could be very useful for many applications in nuclear medicine. Future studies will include developing collimators, improving interface hardwares, and evaluating the system with clinical data.

• Korean small business review
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• v.42 no.1
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• pp.43-56
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• 2020

The technology conflict between the U.S. and China is deepening recently. The U.S.-China battle began as a national security issue but is comprehending as a U.S.'s check for China's rapid technological advancement. China is rapidly growing in several indexes including R&D expenditure, patent application, and publications, and is challenging the U.S. in 5G and Artificial Intelligence. In 2018, Huawei became the largest 5G network/equipment provider and second largest smart phone manufacturer in the world. Now, Huawei is outperforming at AI chipset manufacturing, Bigdata analysis and cloud, positioning to become a critical player in the 4th industrial revolution. The purpose of this research is to analyze the effect of recent Huawei issues to Korean SMEs focusing on the relation between Huawei and Korean companies; the cooperation status from the Global Value Chain (GVC) perpsective, and Korean government's policies related to Huawei's information security issues will be the three main frames for the analysis. Then, this research proposes policy implications such as increasing Korea's competitiveness in manufacturing and information security.