• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2313-2315
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• 2003

This paper presents the development methods which Samsung GPS baseband chip is called S3E4510X. Specification of S3E4510X and design methodology of baseband architecture is presented with a study of their effects. Also GPS core block and software are described in detail. We designed and implemented the test board with RF module for evaluating performance via static test dynamic test and each performance factors using live signal and CPS simulator. Test results show that our development GPS baseband chip have effectively performance for mobile handset Location Based Service (LBS) and its practical use for navigation.

• Journal of Satellite, Information and Communications
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• v.9 no.2
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• pp.85-90
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• 2014

In this paper, we propose a novel UE(User Equipment) position tracking algorithm of visible light signals, and analyze BER performance when optical beamforming scheme is applied in VLC(Visible Light Communications) system. The optical beamforming scheme as an interference mitigation method provides good optical channel conditions between UE(Rx) and LED light(Tx), and lead to better BER performance because UE is able to get a better RSSI(Received Signal strength indication) value. For the system BER, the proposed UE position tracking method for optical beamforming transmission demonstrates the performance enhancement compared to a system not applied the optical beamforming transmission scheme, and up to about 5~6dB SNR performance gain is achieved. The results of the paper can be applied to design of various VLC and LBS applications for ubiquitous home network systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.1
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• pp.218-224
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• 2013

Generally, SAW device, which uses Time Domain Sampling, requires high speed A/D converter because SAW device using TDS needs high sampling speed as much as its high data speed. However, the high price of A/D converter discourages makers from using it. On the other hand, SAW device, which uses Frequency Domain Sampling, does not required high speed A/D converter because SAW device using FDS does not need high sampling speed. It is very efficient in price comparison to its performance because high processing speed of SAW device using FDS can be implemented using low price Embedded Systems. The purpose of the paper is to solve the issues above by designing and realizing SAW device(FDS) using SAW sensor for TDS.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04b
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• pp.1563-1566
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• 2002

The increase of vehicles stagnations leads to the increasing attention to the way customers pay and a large number of projects on electronic cash system. Tranport system is comprised of a number of advanced technologies, including information processing, communications, control, and electronics. Recently many research on a system which provides contact in order to protect driver is vehicle passage have been carried out. And some potential problems from that system are being reviewed by electronic cash system. In this papers, we suggest RF protocol developing technology using the concept of electronic cash. ATM electronic cash developing is consist of component of pre-developed coin throw, integration of component using its, and production of more requirement-satisfactory ITS solution. Result increase $15{\sim}40%$ pre-type vehicles stagnations. Especially, we expect this proposed concept would be well adapted to our national environments.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.91-96
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• 2006

In this paper, the high efficiency Doherty power amplifier has been designed and realized for microwave applications. The Doherty amplifier has been implemented using silicon MRF 281 LOMOS FET. The RF performances of the Doherty power amplifier (a combination of a class AB carrier amplifier and a bias..tuned class C peaking amplifier) have been compared with those of a class AB amplifier alone. The realized Doherty power amplifier PldB output power has 33dBm at 2.3GHz frequency. Also the Doherty power amplifier shows 11dB gain and -17.8dB input return loss at 2.3GHz to 2.4GHz. The designed Doherty amplifier has been improved the average PAE by 10% higher efficiency than a class AB amplifier alone. The Maximum PAE of designed Doherty power amplifier has been 39%.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.277-277
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• 2010

The capacity of the carbonaceous materials reached ca. $350\;mAhg^{-1}$ which is close to theorestical value of the carbon intercalation composition $LiC_6$, resulting in a relatively low volumetric Li capacity. Notwithstanding the capacities of carbon, it will not adjust well to the need so future devices. Silicon shows the highest gravimetric capacities (up to $4000\;mAhg^{-1}$ for $Li_{21}Si_5$). Although Si is the most promising of the next generation anodes, it undergoes a large volume change during lithium insertion and extraction. It results in pulverization of the Si and loss of electrical contact between the Si and the current collector during the lithiation and delithiation. Thus, its capacity fades rapidly during cycling. We focused on electrode materials in the multiphase form which were composed of two metal compounds to reduce the volume change in material design. A combination of electrochemically amorphous active material in an inert matrix (Si-M) has been investigated for use as negative electrode materials in lithium ion batteries. The matrix composited of Si-M alloys system that; active material (Si)-inactive material (M) with Li; M is a transition metal that does not alloy with Li with Li such as Ti, V or Mo. We fabricated and tested a broad range of Si-M compositions. The electrodes were sputter-deposited on rough Cu foil. Electrochemical, structural, and compositional characterization was performed using various techniques. The structure of Si-M alloys was investigated using X-ray Diffractometer (XRD) and transmission electron microscopy (TEM). Surface morphologies of the electrodes are observed using a field emission scanning electron microscopy (FESEM). The electrochemical properties of the electrodes are studied using the cycling test and electrochemical impedance spectroscopy (EIS). It is found that the capacity is strongly dependent on Si content and cycle retention is also changed according to M contents. It may be beneficial to find materials with high capacity, low irreversible capacity and that do not pulverize, and that combine Si-M to improve capacity retention.

• The Korean Journal of Nuclear Medicine
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• v.39 no.1
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• pp.1-8
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• 2005

This paper is described on the development of KOTRON-13 and recent status of PET cyclotron by commercial cyclotron companies. KIRAMS has developed medical cyclotron which is KIRAMS-13. Samyoung Unitech produces KOTRON-13 with transfered technology by KIRAMS. As a part of Regional Cyclotron Installation Protect, KOTRON-13 cyclotrons and $[18F]FDG$ production modules are being installed at regional cyclotron centers in Korea. The medical concern with radiation technology has been growing for the last several years. Early cancer diagnosis through the cyclotron and PET-CT have been brought to public attention by commercial cyclotron models in the world. The new commercial cyclotron models are introduced compact low energy cyclotrons developed by CTI, GE, Sumitomo in recent. It produces different short-lived radioisotopes, such as $[^{18}F],\;[^{11}C],\;[^{13}N]\;and\;[^{15}O]$. For the better reliability acceleration particle is proton only. The characteristics of new model cyclotrons are changed to lower energy corresponding to less 13 MeV. New models have self-shielding and low power consumption. Design criteria for the different types of commercial cyclotrons are described with reference to hospital demands.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.4
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• pp.846-851
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• 2007

The wireless sensor network is one of the most practical and cost-effective solutions for monitoring systems covering wild and wide area such as wildfire monitoring. However, the RF distance between sensor nodes is very short due to the need of low power consumption of the sensor node, so the number of sensor nodes to be deployed in the target area is more than tens of thousands. In this paper, we design and analyze the deployment issues as well as re-deployment problem occurred when the battery is exhausted. We also propose the needs and solutions for coverage problem in dynamic deployment. By the experimental evaluations, we analyze the packet success ratio between sensor nodes under various environments such as obstacles and variable distances.

• Journal of Convergence for Information Technology
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• v.7 no.2
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• pp.53-58
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• 2017

This paper describes the design of a simulator for analyzing the accuracy of a correlative interferometer(CI) direction finder. CI direction finder is robust to noise, so it is often used in aircraft or ships where complex antenna installation is required, and the direction finding accuracy is very high. When the radio wave is incident at a specific azimuth angle, the phase difference calculated in a noiseless environment and the phase difference measured in a real environment with noise are fused to estimate the largest correlation coefficient as the azimuth angle of the radio wave. The simulator receives RF frequency, the number of antennas, the antenna coordinates, the transmission signal intensity, the bandwidth of the receiver, the gain and the payload effect, and calculates the direction finding accuracy of 0-360 degrees azimuth and 0-60 degree elevation with 0.5 degree. accuracy.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.5
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• pp.11-18
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• 2021

The small radio frequency tracking radar is a tracking system with a radio frequency sensor that identifies a target through all-weather radio frequency signal processing for a target and searches, detects and tracks the target for the major target. In this paper, we describe the development of a board equipped with TMS320C6678 and XILINX FPGA (Field Programmable Gate Array), a high-speed multi-core DSP that acquires target information through all-weather radio frequency and identifies a target through real-time signal processing. We propose DSP-FPGA combination architecture for DSP and FPGA selection and signal processing, and also explain the design of SRIO for high-speed data transmission.