• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.33A no.4
• /
• pp.98-105
• /
• 1996

The design method of 85 GHz-115 GHz band single side-band filter using the principle of martin-puplett inteferometer is described. It has been designed by this method and also manufactured and tested. From the test results, not only the ratio of image singal rejection of 19 dB is obtained, but also the theoretical and experimental results of center frequency of pass-band and rejection-band show the validity of the theory. This manufactured filter was installed on 100GHz band SiS (superconductor insulator superconductor ) receiver for observing cosmic radio waves and tested. We found that this filter can be used a single side-band as well as double side-band mode. The design method which is presented in this paper can be used a single side-band filter for a heterodyne type sub-milimeter wave receiver.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.10a
• /
• pp.609-611
• /
• 2013

There's little to obstacles obstructing communication in the sky. There are nearly fixed obstacles obstructing communication on the ground. But communication disruption can be occur frequently and unexpectedly on the sea surface. Especially, it is difficult for a small station which can be greatly affected by waves and low antenna height to secure the LOS for radio communication. In this paper, LOS and minimum antenna height is calculated due to changing wave height and Tx/Rx antenna height on the sea surface.

• Journal of Haehwa Medicine
• /
• v.19 no.1
• /
• pp.9-15
• /
• 2010

Objective : The purpose of the study was to evaluate if the oriental medicine treatment with hot acupuncture are more effective and safer in the carpal tunnel syndrome. Methods : We treated total 5 patients with hot acupuncture high-frequency radio waves. We evaluated VAS(visual analog scale) and subjective symptoms of patients after executing. Results : The following results were obtained ; 1. It was evaluated that the oriental medicine treatment with hot acupuncture was significant in improvement of symptoms in each treatment. 2. In VAS score, It was evaluated that carpal tunnel syndrome patient were significant in improvement of symptoms. 3. In subjective symptoms, It was evaluated that carpal tunnel syndrome patient were significant in improvement of symptoms. Conclusion : The results suggest that hot acupuncture is the effective on the treatment of carpal tunnel syndrome.

• Journal of the Korea Society of Computer and Information
• /
• v.22 no.1
• /
• pp.33-40
• /
• 2017

In this paper, we introduce commercial indoor navigation systems being deployed and serviced in many fields of industry focusing on their indoor positioning technologies. Indoor positioning technology is a technology that locates people or targets in the interior of a building. To do that, it utilizes radio waves such as WiFi, and bluetooth, magnetic fields, or other sensory information from smart phones. We present indoor navigation systems categorizing them into their indoor positioning technologies. We define important performance issues for indoor positioning technologies and analyze them according to the performance issues. We believe that this paper provide wise view and necessary information for recent indoor navigation systems.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.2
• /
• pp.129.2-129.2
• /
• 2012

Solar flares and coronal mass ejections (CMEs) are two major solar eruptive phenomena which can cause enormous economic and commercial losses: (1) flares are sudden, rapid, and intense brightenings from radio waves to Gamma-rays in the chromosphere and corona, and (2) CMEs are large-scale transient eruptions of magnetized plasma from the solar corona that propagate outward into interplanetary space. Most flares and CMEs occur in magnetically complicated solar active regions (ARs). Therefore, it is crucial to investigate magnetic fields in ARs and their temporal variations for understanding a precondition and a trigger mechanism related to flare/CME initiation. In this presentation, we will introduce an automated system for empirical forecasting of flares and CMEs in ARs using full-disk photospheric line-of-sight magnetogram data taken by the Helioseismic and Magnetic Imager (HMI) onboard the SDO.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.13 no.4
• /
• pp.642-649
• /
• 2010

LOS analysis is used for optimal deployment of mid-range guided weapon system or system engagement effectiveness simulation. Comparing to real-world, LOS analysis includes error sources such as coarse terrain data resolution, refraction of radio waves, and several ideal assumptions. In this research, exact LOS algorithm under assumption of constant earth curvature and error analysis of that is investigated. It proved that LOS algorithm under assumption of constant earth curvature has negligible error in mid-range guidance weapon system's scope.

• Journal of the Korean Institute of Navigation
• /
• v.4 no.1
• /
• pp.1-18
• /
• 1980

As the NNSS system calculates ship's position by the doppler shift of the NNSS radio waves caused by the change of the distance between Transit Satellite and the ship, ship's speed error inevitably results in the position error, and moreover this kind of erroris most dominant compared with other errors especially in high speed ships and airplanes. Most NNSS receivers now in use have adoptedsuccessive short doppler counts as positioning data and by investigating the dispersion of serval successive positions calculated and by neglecting the mean position having dispersion of over certain threshold level, more accurate adn safe position is to be achieved. This paper proposes the method of finding ship's true speed by selecting a speed having least position dispersion for given successive doppler counts. And by computer simulation it was verified that the method proposed here is reasonable in finding the ship's desired correct speed together with the correct ship's position.

• Journal of Biomedical Engineering Research
• /
• v.27 no.1
• /
• pp.22-29
• /
• 2006

This paper proposes an efficient array beamforming method using spatial matched filtering for ultrasound imaging. In the proposed method, ultrasound waves are transmitted from an array subaperture with fixed transmit focus as in conventional array imaging. At receive, radio frequency (RF) echo signals from each receive channel are passed through a spatial matched filter that is constructed based on the system transmit-receive spatial impulse response. The filtered echo signals are then summed. The filter remaps and spatially registers the acoustic energy from each element so that the pulse-echo impulse response of the summed output is focused with acceptably low side lobes. Analytical beam pattern analysis and simulation results using a linear array show that the proposed spatial filtering method can provide more improved spatial resolution and contrast-to-noise ratio (CNR) compared with conventional dynamic receive focusing (DRF) method by implementing two-way dynamically focused beam pattern throughout the field.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.65.4-65
• /
• 2001

In case of data transmission using the upper 10GHz frequency, rain results in attenuation of radio waves. And the most serious atmospheric effect in a satellite link is the rainfall. The attenuation of rainfall very seriously affects the quality of transmission line. Because the rain increases thermal noise and interference, and decreases the amplitude of the signal. KOWACO manages the VSAT system instead of VHF network for communication of rain and water-level data from 1998. The purpose of this system is to monitor the change of water-level and rain data during a flood duration. VHF system acquires the data by a call per a hour. But the satellite network obtains the data whenever event data occur. Thus the satellite network is more powerful than the VHF system. In study ...

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2014.05a
• /
• pp.473-474
• /
• 2014

Radio frequency identification system (RFID) is an automatic technology and aids machines or computers to identify objects, record metadata or control individual target through wireless waves. Connecting RFID reader to the terminal of Internet, the readers can identify, track and monitor the objects attached with tags globally, automatically, and in real time, if needed. This is the so-called Internet of Things (IOT). RFID is often seen as a prerequisite for the IOT. This paper surveys the technologies of RFID and IOT, discusses the applications and challenges of RFID technology used in IoT.