• Journal of Advanced Navigation Technology
• /
• v.18 no.3
• /
• pp.209-214
• /
• 2014

Current black boxes have a problem of storing unnecessary imagery data recordings without data classification. For this reason, users have to erase videos every time. This method is inadequate for black boxes with limited memory capacity. In this paper, we design and implement a system that recognizes traffic accident situations and saves these recordings by classifying them according to weighted values. The system was made to save video recorded at a 30-sec interval of every event to black box folders by changing names based on weighted value data under the external environment in a 1:10 scale model car. Based on this, when the tests were performed as a major car accident while driving, the videos were created in w2 folder, and when the tests were performed as a minor car accident while stopped, the videos were created in w1 folder.

• Proceedings of the KOSOMBE Conference
• /
• v.1997 no.05
• /
• pp.216-219
• /
• 1997

We are developing a portable multipurpose gamma counting and imaging probe that will be useful for many applications in nuclear medicine including radioimmunoguided surgery in the detection and treatment of malignant tumors. Any diagnostic information provided by CT, MRI, PET, SPECT or gamma camera imaging prior to surgery obviously is very important, but current techniques are limited in many instances. To overcome some of these limitations, the portable multipurpose gamma probe is being developed. The gamma probe consists of NaI(Tl) crystal with 1" dia $\times$ 0.5" thick and singlechannel photomultiplier tube (SC-PMT) for counting, and 3" dia $\times$ 0.375" and multichannel photomultiplier tube (MC-PMT) for imaging, nuclear instrument module (NIM), position circuits, interface, and PC. The energy resolution using Tc-99m was measured as 14% and the spatial resolution using 3mm dia green LED was measured as 2.9mm. These priliminary results indicate that the currently developing probe is very promising and could be very useful for many applications in nuclear medicine.

• Journal of Satellite, Information and Communications
• /
• v.10 no.1
• /
• pp.83-87
• /
• 2015

LED navigation light installed on the ship performs a important role to ensure safety and prevent collisions with other ships. LED navigation light is mainly used in the night and within the limited visibility by smoke, rainfall. In particular, LED navigation light installed with a clear understanding. LED navigation light is consist of LED module, a control board, a converter, a Fresnel lens, such as enclosure. Russian Society of LED navigation light (RMRS) of the ship to be delivered by drying at Daewoo Shipbuilding & Marine Engineering requires guaranteed reliable products at below $-52^{\circ}C$. conventional LED navigation light has to ensure quality at $-25{\sim}40^{\circ}C$. So, LED navigation light should ensure a problems of random failure or long time operation. In this paper, we present the current status and future plans of reliability so far.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2018.05a
• /
• pp.705-708
• /
• 2018

Among biometrics commercialized for security, iris recognition technology has the most excellent security for the probability of the match between individuals is the lowest. Current commercialized iris recognition technology has excellent recognition ability, but this technology has a fatal drawback. Without the user's active cooperation, it cannot recognize the iris correctly. To make up for this weakness, recent trend of iris recognition development mounts a non-volunteering, unconstrained method. According to this information, the objective of this research is developing a module that can identify people iris from a video acquired by high performance infrared camera in a range of 3m and in a involuntary way. For this, we import images from the video and find people's face and eye positions from the images using Haar classifier trained through Cascade training method. finally, we crop the iris by Hough circle transform and compare it with data from the database to identify people.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.3
• /
• pp.681-686
• /
• 2017

Degradation is commonly observed in field-aged PV modules due to corrosion of the photovoltaic ribbon. The reduced performance is caused by a loss of fill factor due to the high series resistance in the PV ribbon. This study aimed to mitigate the degradation by corrosion using five sacrificial anodes - Al, Zn and their alloys - to identify the most effective material to mitigate the corrosion of the PV ribbon. The corrosion behavior of the five sacrificial anode materials were examined by open circuit potential measurements, potentiodynamic polarization tests, and galvanic current density and potential measurements using a zero resistance ammeter. Immersion tests for 120 hours were also conducted using materials and damp heat test tests were performed for 1500 hours using 4 cell mini modules. The Al-3Mg and Al-3Zn-1Mg sacrificial anodes had a low corrosion rate and reduced drop in power, making then suitable for long-term use.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.7
• /
• pp.109-114
• /
• 2013

Power MOSFET (metal-oxide semiconductor field-effect transistor) are widely used in power electronics applications, such as BLDC (Brushless Direct Current) motor and power module, etc. For the conventional power MOSFET device structure, there exists a tradeoff relationship between specific on-state resistance and breakdown voltage. In order to overcome the tradeoff relationship, a non-uniform super-junction (SJ) trench MOSFET (TMOSFET) structure for an optimal design is proposed in this paper. It is required that the specific on-resistance of non-uniform SJ TMOSFET is less than that of uniform SJ TMOSFET under the same breakdown voltage. The idea with a linearly graded doping profile is proposed to achieve a much better electric field distribution in the drift region. The structure modelling of a unit cell, the characteristic analyses for doping density, and potential distribution are simulated by using of the SILVACO TCAD 2D device simulator, Atlas. As a result, the non-uniform SJ TMOSFET shows the better performance than the uniform SJ TMOSFET in the specific on-resistance at the class of 100V.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.28 no.5
• /
• pp.430-433
• /
• 2017

This paper presents a S/C/X-band LNA MMIC with resistive feedback structure in 0.25 um GaN HEMT process. The GaN devices have advantages as a high output power device having high breakdown voltage, energy band gap and stability at high temperature. Since the receiver using the GaN device with high linearity can be implemented without a limiter, the noise figure of the receiver can be improved and the size of receiver module can be reduced. The proposed GaN LNA MMIC based on 0.25 um GaN HEMT device is achieved the gain of > 15 dB, the noise figure of < 3 dB, the input return loss of > 13 dB, and the output return loss of > 8 dB in the S/C/X-band. The current consumption of GaN LNA MMIC is 70 mA with the drain voltage 20 V and the gate voltage -3 V.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.13 no.2
• /
• pp.243-251
• /
• 2010

The military has been putting great efforts into applying data communication on existing voice communication systems being used in NCW(Network Centric Warfare). Data communication will be an effective choice in one of many effort to yield a minimum kill chain, comparing to legacy voice communications, when tactical units conduct their missions. However, the required budget will be enormous, in case of the replacement of a lot of legacy communication systems with new one. As a cost-effective alternative, the tactical data communication systems using the conventional radio systems instead of the development of new radio systems has been proposed. It is mandatory, though, to ensure QoS while maintaining data communication by making use of legacy radio systems already in use. This paper focuses on the performance issues experimented and analyzed for tactical data communication through the legacy radio systems as the first step towards guaranteed QoS. We have conducted various experiments such as the transmission error rate on certain tactical messages, performance evaluation of redundant transfers, the relationship between the transmission frame size and rate of error, the identification of error points in the transmission frame, and techniques to reduce the errors in both hopping and non-hopping modes. As a result of the performance experiments, The adaptive communication module which decides the redundant transmission or the Forward Error Correction(FEC) technique by analyzing channel status and current transmission status(hopping/non-hopping) of the legacy radio should be designed. the FEC technique in non-hopping, and the redundant transmission technique in hopping mode was recommended from the result of experiment with the frame size is 20bytes in non-hopping and 10Bytes frame size in hopping mode.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.12B
• /
• pp.735-742
• /
• 2007

We propose an effective packet marking algorithm for video streaming in DiffServ network. Because legacy packet markers such as srTCM(single rate three color marker) cannot distinguish the importance of packet, these markers can cause quality degradation of streaming during the network congestion period. Recently proposed TMS (Two Marker System) [4] shows effectiveness in such scenario that video streaming service is struggling with other types of service traffic. However, if many video streaming services co-exist in DiffServ network and result in competition among themselves, then both legacy packet markers and even TMS cannot prevent drastic streaming quality degradation. To cope with this, we suggest A-TCPM (Adaptive time sliding window Three Color Marker) algorithm. In this algorithm, an A-TCPM module decides the color of a racket based upon the probability which is lead by current channel status and frame importance ratio. Simulation results show that proposed A-TCPM algorithm can enhance streaming service quality especially when overbooked video streaming sessions struggle with themselves.

• Proceedings of KOSOMES biannual meeting
• /
• 2007.11a
• /
• pp.51-55
• /
• 2007

As for satellite programs, the multipurpose satellite 1(KOMPSAT-1) was successfully launched on Dec. 21, 1999 and operated for three years. It is still properly operated even though its life cycle was ended. The development of KOMPSAT-2 (Korea Multipurpose Satellite-2) is near completion and the development of KOMPSAT-3, KOMPSAT-5 and COMS (Communication, Ocean, Meterological Satellite) are proceeding swiftly. In KORDI(Korea Ocean Research and Development Institute), the KOSC (Korea Ocean Satellite Center) construction project is being prepared for acquisition, processing and distribution of sensor data via L-band from GOCI(Geostationary Ocean Color Imager) instrument which is loaded on COMS(Communication, Ocean and Meteorological Satellite); it will be launched in 2000. Ansan(the headquarter of KORDD has been selected for the location of KOSC between 5 proposed sites, because it has the best condition to receive radio wave. The data acquisition system is classified antenna and RF. Antenna is designed to be ${\emptyset}$ 9m cassegrain antenna which has 19.35 $G/T(dB/^{\circ}K)$ at 1.67GHz, RF module, is divided into LNA(Low noise amplifier) and down converter, those are designed to send only horizontal polarization to modem The existing building is re-designed and classified for the KOSC operation concept; computing room, board of electricity, data processing room, operation room Hardware and network facilities have been designed to adapt for efficiency of each functions. The distribution system which is one of the most important systems will be constructed mainly on the internet, and it is also being considered constructing outer data distribution system as a web hosting service for to offering received data to user under an hour.