• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.5A
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• pp.436-444
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• 2005

Unitary matrix modulation (UMM) is investigated in multiple antennas system that is called unitary space-time modulation (USTM). In an OFDM, the diagonal components of UMM with splitting over the coherence bandwidth (UMM-S/OFDM) have been proposed. Recently LDPC code is strongly attended and studied due to simple decoding property with good error correction property. In this paper, we propose LDPC coded UMM-S/OFDM for increasing the system performance. Our proposed system can obtain frequency diversity using UMM-S/OFDM like USTM/OFDM, and large coding gain using LDPC code. The superior characteristics of the proposed UMM-S/OFDM are demonstrated by extensive computer simulations in multi-path Rayleigh fading channel.

• Journal of Digital Convergence
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• v.16 no.9
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• pp.489-495
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• 2018

The purpose of this study was to investigate the effect of fouls on performance in field hockey games. A total of 33 matches and 2101 fouls from 10 teams participated in the 2017 World League SEMI-FINAL tournament were analysed by region, race, type, and cause. The total data that is analysed by SportsCode and SPSS(correlation analysis & chi-square test)have showed that the top ranked countries had a higher foul frequency than the lower ranked nations. According to the situation that has showed the result of the analysis, it showed that there was no difference between the results analysed on the foul type and the attacking and defence situation but it has indicated that area, game situation and the cause of fouls showed there was a significant difference. On these results, it is hoped to use fouls as one of the tactical means in women's field hockey games.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.8
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• pp.79-85
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• 2009

In this paper, an accurate current reference using temperature and process compensation current mirror (TPC-CM) is proposed. The temperature independent reference current is generated by summing a proportional to absolute temperature (PTAT) current and a complementary to absolute temperature (CTAT) current. However, the temperature coefficient and magnitude of the reference current are influenced by the process variation. To calibrate the process variation, the proposed TPC-CM uses two binary weighted current mirrors which control the temperature coefficient and magnitude of the reference current. After the PTAT and CTAT current is measured, the switch codes of the TPC-CM is fixed in order that the magnitude of reference current is independent to temperature. And, the codes are stored in the non-volatile memory. In the simulation, the effect of the process variation is reduced to 0.52% from 19.7% after the calibration using a TPC-CM in chip-by-chip. A current reference chip is fabricated with a 3.3V 0.35um CMOS process. The measured calibrated reference current has 0.42% variation for $20^{\circ}$C${\sim}$100$^{\circ}$C.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.5
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• pp.108-114
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• 2010

The injection nozzle of an electro-hydraulic injector is being opened and closed by movement of a injector's needle which is balanced by pressure at the nozzle seat and at the needle control chamber, at the opposite end of the needle. In this study, the effects of needle movement in a piezo-driven injector on unsteady cavitating flows behavior inside nozzle were investigated by cavitation numerical model based on the Eulerian-Lagrangian approach. Aimed at simulating the 3-D two-phase flow behavior, the three dimensional geometry model along the central cross-section regarding of one injection hole with real design data of a piezo-driven diesel injector has been used to simulate the cavitating flows for injection time by at fully transient simulation with cavitation model. The cavitation model incorporates many of the fundamental physical processes assumed to take place in cavitating flows. The simulations performed were both fully transient and 'pseudo' steady state, even if under steady state boundary conditions. As this research results, we found that it could analyze the effect the pressure drop to the sudden acceleration of fuel, which is due to the fastest response of needle, on the degree of cavitation existed in piezo-driven injector nozzle.

• Journal of Navigation and Port Research
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• v.29 no.10 s.106
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• pp.877-882
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• 2005

It is necessary that Fail-Safe Seaway technology providing a continuous navigation solution though fault of navigation system is occurred in sea. This paper focus on signal processing of GPS receiver, one of receivers using the software radio technology to implement a integrated radio navigation system including satellite-based and ground-based navigation systems. It is difficult to implement the software GPS receivers using a commercial processor because of the heavy computational burden for processing the GPS signals in real time. This paper proposes an efficient multi-bit GPS signal processing scheme to reduce the computational burden for processing the GPS signals in the software GPS receiver. The proposed scheme uses a compression concept of the multi-bit replica signals and patterned look-up table method to generate the correlation value between the GPS signals and the replica signals.

• Journal of Navigation and Port Research
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• v.40 no.6
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• pp.369-374
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• 2016

Recently, due to the rapid development of smart computing technology, there have been a lot of studies on 3D navigation, and consequently the advanced commercial 3D navigation system and 3D VTS system are on the market. Even the 3D technology is well known and wide spreaded, unfortunately, the secret of code behind is still unleashed. The purpose of this paper is to show the basic methodologies to display ENC features under 3D display environment to meet the requirement of S-52 standards. The OpenGL ES is used to develop 3D ENC Viewer for further use on mobile platforms and web based vessel monitoring system. P articularly, area object triangulation, complex line drawing, polygon pattern filling and symbol drawing by texture mapping are explained in detail. The result of performance test is shown as table for correlation of SENC file size to display speed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.12
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• pp.2813-2819
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• 2015

In this paper, we investigate the physical layer network coding (PNC) technique in a two-way relay channel (TWRC) where two source nodes send and receive data with each other via a relay node. In particular, we consider the communication scenario where packet length from the two sources is different from each other. We analyze the bit error rate (BER) of the received packet at the relay node according to degree of overlapping between two packets. The BER of the short packet remains unchanged regardless of the degree of overlapping since the entire packet is overlapped with the longer packet, while the BER of the longer packet becomes improved as the degree of overlapping decreases. Thus, we need a novel transmission scheme to enhance BER performance of the PNC technique in TWRC environments since the overall BER performance of the PNC technique at the relay node depends on the worse BER between two ovelapping packets' BERs.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2004.11a
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• pp.69-71
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• 2004

The proton therapy of radiation therapy methods using Bragg Peak which is proton beam's characteristic dose distribution can give a normal tissue lower dose than cancer, comparing with the former existing radiation therapy methods. For exact treatment and patient' safety, we need to know proton beam's position in body, but a proton beam completely stops at treatment region and proton beam's range is uncertainly made by the variety of organs having each different density, so we aren't able to find a proton beam' position by suitable methods yet. With Monte Carlo Computing Method, as a result that we had simulated prompt gamma detection system using correlation of proton beam's absorbed dose distribution about water and prompt gamma distribution by nuclear interaction occurred by collisions of proton and water's hydrogen atoms, we could confirm that a proton beam's position was able to detect by using simulated prompt gamma detection system in body on the real-time

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.449-454
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• 2010

In this paper, flow characteristics of R600a in an adiabatic capillary tube were investigated employing the homogeneous flow model. The model is based on fundamental equations of mass, energy and momentum which are solved simultaneously. Two friction factors(Churchill) and viscosity(McAdams) are comparatively used to investigate the flow characteristics. Thermodynamic and transport properties of R600a are calculated employing EES property code. Flow characteristics analysis of R600a in an adiabatic capillary tube is presented to offer the basic design data for the operating parameters. The operating parameters considered in this study include condensation temperature, evaporation temperature, subcooling degree and inner diameter tube of the adiabatic capillary tube. The main results were summarized as follows: condensation and evaporation temperature, inlet subcooling degree and inner diameter tube of an adiabatic capillary tube using R600a have an effect on length of an adiabatic capillary tube. The length of an adiabatic capillary tube using R600a is expressed to the correlation shown in Eq. (15).

• Journal of Ocean Engineering and Technology
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• v.22 no.4
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• pp.90-96
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• 2008

In general, the swing motions of a crane are controlled and suppressed by controlling the trolley motion. In many of our previous studies, we suggested a new type of anti-sway control system for a crane. In this proposed control system, a small auxiliary mass (moving-mass) is installed on the spreader and moving this auxiliary mass controls tire swing motion. The actuator reaction against the auxiliary mass applies inertial control forces to the container in order to reduce the swing motion in the desired manner. However, measuring systems based on a laser sensor or other means are not veryuseful in real-worldapplications. So, in this paper, animage sensor is used to measure the motions of the spreader and the measured data are fed back to the controller in real time. The applied image processing technique is a kind of robust template matching method called Vector Code Correlation (VCC), which was devised to consider real environmental conditions. The H $\infty$ based control technique is applied to suppress the swing motion of the crane. Experimental results showed that the proposed measurement and control system based on an image sensor is useful and robust to disturbances.