• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.491-492
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• 2022

본 연구에서는 실내 공간 정보 획득을 위한 IMU/INS 항법장치에 관한 연구를 위한 선행연구를 수행 하였다. 최근의 GPS를 이용한 내비게이션의 경우 보통 5~10m의 위치 오차가 일어나지만 아파트나 대형시설과 같이 실내, 터널, 공장지대 및 산악 지대등 상당한 지역은 GPS의 사각지대 또는 오차 범위를 벗어난 지역으로 존재하고 있다. 따라서 GPS는 실내에서는 사용이 불가능 하므로 다른 방안이 제시되어야 한다. 현재 고속 연산을 위한 고성능 마이크로프로세서의 발전은 센서 분야에 적용되어 저 전력, 고 정밀, 소형의 IMU/INS, ARS/AHRS 센서가 개발되고 있다. 본 연구에서는 IMU(inertial measurement unit)와 INS(Inertial Navigation System)을 이용하여 IMU자체의 자이로 센서와 가속도 센서를 이용한 GPS의 위성신호가 감지되지 않는 지형에서도 속도의 적분값과 회전방향을 이용하여 위치인식이 가능하도록 정보를 계산하여 자기의 위치를 추적하는 방안을 연구하였다.

• Korean journal of applied entomology
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• v.47 no.1
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• pp.75-86
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• 2008

Many kinds of environment friendly agricultural materials (EFAMs) were used for the plant protection, furthermore they support the growth of crops in the greenhouses and the kindly environment friendly farming. Natural enemies might be used for control of insect pest with EFAMs at the same space and time. For testing the toxicity of EFAMs against to natural enemies, 10 EFAMs were selected and tested in small greenhouses and farm's fields. In case of Harmonia axyridis larva, there was no predacious activity against cotton aphids in the block with EFAMMo L, EFAMPE D, EFAMME G and EFAMAE A, otherwise, aphid population was rapidly decreased in the control block without EFAMs. Both of Trialeurodes vaporariorum and Encarsia formosa population were slightly decreased in the block with EFAMs. There were significantly decreased in the block with IEFAM C, FEFAM D, EFAMSM Band EFAMPE D compared with control area. Especially, there was significantly maintained a very low population, both T. vaporariorum and E. formosa in the block with EFAMMo C. The parasitized ratio of Aphidius colemani is also very low in the block with EFAMs compared with control area. In the block with IEFAM C, FEFAM D, EFAMPE D and EFAMMo L, there were significantly different with control area in the number of mummies. Otherwise, in case of Diglyphus isaea and Liriomyza trifolii, there was no significantly different between blocks with and without EFAMs. In the block with EFAMMo C, Tetranychus urticae and Phytoseiulus persimilis populations were significantly maintained a very low level. However, the population of T. urticae was increased, but P. persimilis was decreased in the block with EFAMMo L.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.1
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• pp.27-33
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• 2020

Recently, visual object detection and tracking has become a vital role in many different applications. It spans various applications like robotics, video surveillance, and intelligent vehicle navigation. Especially, in current situation where the use of UAVs is expanding widely, detection and tracking to soot down illegal UAVs flying over the sky at airports, nuclear power plants and core facilities is becoming a very important task. The remarkable method in object tracking is correlation filter based tracker like KCF (Kernelized Correlation Filter). But it has problems related to target drift in tracking process for long-term tracking. To mitigate the target drift problem in video surveillance application, we propose a tracking method which uses KCF, adaptive thresholding and Kalman filter. In the experiment, the proposed method was verified by using monochrome video sequences which were obtained in the operational environment of UAV.

• The Journal of the Korea Contents Association
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• v.16 no.8
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• pp.387-394
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• 2016

The volatility in the stock market responds differently to information types. That is, the asymmetric volatility exists in the stock market which responds more to unexpected negative returns due to bad news than unexpected positive returns due to good news. This paper examines the asymmetric response of the volatility of KOSPI, large-cap, middle-cap, and small-cap indices returns which is announced in Korea exchange (KRX) by using the MA-GJR model and the MA-EGARCH model. According to empirical analyses, it shows that the asymmetric response of volatility exists in all indices regardless of volatility estimation models and the degree of the asymmetric volatility response of the small-cap index returns is greater than that of the large-cap index returns. Moreover, this results also observed robustly during the period of both before and after the global financial crisis.

• Journal of the Korea Society of Computer and Information
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• v.20 no.3
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• pp.89-96
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• 2015

IT is widely used for biomechanics and AHRS sensor also be highlighted with small sized characteristics and price competitiveness in the field of motion measurement and analysis of sports. In this paper, we attach the AHRS to the figure skate shoes to measure the motion data like spin, forward/backward, jump, in/out edge and toe movement. In order to reduce the measurement error, we have adopted the sensors equipped with Madgwick complementary filtering and also use Euler angle to quaternion conversion to reduce the Gimbal-lock effect. We test and experiment the accuracy and execution time of the pattern recognition algorithms like PCA, ICA, LDA, SVM to show the recognition possibility of it on the basic motions of figure skating from the 9-axis trajectory information which is gathered from AHRS sensor. From the result, PCA, ICA have low accuracy, but LDA, SVM have good accuracy to use for recognition of basic motions of figure skating.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.4
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• pp.415-421
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• 2013

This study describes the aerodynamic design procedure for the axial turbines of a small heavy-duty gas turbine engine being developed by Doosan Heavy Industries. The design procedure mainly consists of three parts: namely, flowpath design, airfoil design, and 3D performance calculation. To design the optimized flowpath, through-flow calculations as well as the loss estimation are widely used to evaluate the effect of geometric variables, for example, shape of meridional plane, mean radius, blades axial gap, and hade angle. During the airfoil design procedure, the optimum number of blades is calculated by empirical correlations based on the in/outlet flow angles, and then 2D airfoil planar sections are designed carefully, followed by 2D B2B NS calculations. The designed planar sections are stacked along the spanwise direction, leading to a 3D surfaced airfoil shape. To consider the 3D effect on turbine performance, 3D multistage Euler calculation, single row, and multistage NS calculations are performed.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.4
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• pp.39-45
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• 2008

Breakaway support for small signs of size $0.293\;m^2{\sim}0.360\;m^2$ using indented tube type bolt of D12 mm with 6 mm inner diameter has been developed and the structural strength of the support system for the wind load was verified through static shear and tension tests. One important value in understanding the dynamic behavior of sign post and impact vehicle is the fracture energy of the sign support. In this study, fracture energy needed to break the sign support was estimated by pendulum test and computer simulation using LS-DYNA program. Support system composed of 3 indented bolts was found to sustain the 43.1 kg$\sim$51.2 kg wind load safely. Fracture energy for one indented bolt was measured as 163.3J from the pendulum test, and was calculated as 153J from the LS-DYNA simulation. The closeness between these two values verified the validity of the simulation model.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.537-541
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• 2009

The gas turbine engine performance is greatly relied on its component performance characteristics. Generally, acquisition of component maps is not easy for engine purchasers because it is an expensive intellectual property of gas turbine engine supplier. In the previous work, the maps were inversely generated from engine performance deck data, but this method is limited to obtain the realistic maps due to calculated performance deck data. Therefore this work proposes newly to generate more realistic compressor map from experimental performance test data. And then a realistic compressor map can be generated form those processed data using the proposed extended scaling method at each rotational speed. Evaluation can be made through comparison between performance analysis results using the performance simulation program including the generated compressor map and on-condition monitoring performance data.

• Korean journal of applied entomology
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• v.12 no.2
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• pp.57-62
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• 1973

한국의 뽕나무 해충은 210종 이상이 기록되었다. 과거 4반세기 동안 다수의 합성농약이 농림해충 및 위생해충 방제에 큰 공헌을 해 온 것은 주지의 사실이다. 그러나 뽕나무의 해충에 대해서는 농약에 대한 내약력이 가장 약한 누에에 미칠 악영향 때문에 여러 가지 어려운 점이 많아서 외국에서도 잔효성이 짧은 TEPP 또는 DDVP등이 사용되고 있을 정도이다. 한국에서도 뽕나무순혹파리 방제를 위해서 초여름에 BHC 분제의 토양처리가 실천되어 왔으며 근래에는 뽕나무애바구미의 피해가 심해져서 몇 가지 살충제로 방제시험이 백에 의해서 이루어 졌을 뿐이다· 따라서 뽕나무해풍 방제를 위해서는 천적을 이용한 방제가 바람직하다 하겠다. 필자들은 우선 천적으로서의 거미의 분포 실태를 파악하기 위하여 수원시 소재 잠업시험장 뽕밭에서 1971-72년에 조사하였다. (Fig. 1) 조사된 뽕밭의 면적을 27a이었으며 9개의 조사구를 택하고 이것을 생태적 환경에 따라 3군으로 나누어 비교해 보았다. A, B 및 C구는 동쪽 가에 위치하며 가로등과 3개의 잠실의 등불의 영향을 받아 해충의 밀도가 높았으며 E, D 및 H구는 뽕밭의 중앙부이며 뽕나무 오갈병의 피해가 심하여 뽕나무가 작았고 또한 결주도 많았다. F, G 및 I구는 도로를 격하고 뽕밭 또는 초지에 면한 가장자리 이었 다. 이밖에 수시로 근처의 딴 뽕밭에서 채집한 것도 포함하여 4,987마리의 거미를 조사한 바 17과 47속 66종에 이르렀다. 이것을 Abe의 보고와 비교한 때 종수가 월등 많았으며 또한 Kayashima의 보고와는 달리 풀거미속(Agelena)거미가 훨씬 적은 것이 특이하였다. 채집된 거미를 그 생태에 기초하여 4군으로 나누어 천적으로서의 가치를 비교해 보면 다음과 같다. A군 : 대형의 둥근 망을 치는 종류들로서 날으는 곤충을 잡아먹는데 천적으로서 그다지 중요하지는 않다. 106주에서 245마리가 채집되었으며 (Tetragnatha squamata)가 우량종이었다. B군 : 소형의 둥근 망을 가지나 잎사이에 치는 종들로서 비록 몸은 작지만 가장 중요한 천적이다. 꼬마거미과 애접시거미과에 속하는 거미들이며 18종, 2,815마리가 잡혔다 우점종은 (Erigoridium raminicola),(Theridion octomaculata) (Enoplognatha spp.)이었다. C군 : 떠돌이거미로서 소형곤충을 잡아먹어 유력한 천적이다 26종 1,727마리가 잡혔으며 게거미과, 깡총거미과 및 염낭거미과의 거미들이 우점종이었다. D군 : 지상을 걸어다니는 떠돌이거미로서 늑대거미과가 약간 잡혔으나 천적으로서 중요한 것으로는 생각되지 않는다. 앞으로 이들과 해충과의 관계를 조사구명 해야 할 것이다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.5
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• pp.792-797
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• 2006

In this paper, an internal integrated microstrop patch for PCS handset is designed. To increase the bandwidth of microstrip patch antenna, a configuration of stacked type using parasitic element is used. Furthermore, to reduce the size of microstirip patch antenna, the main radiator in the substrate is shorted to the ground plane using five shorting-posts while three parasitic elements on the superstrate are also shorted to the ground plane using two shorting-posts respectively. The antenna bandwidth and radiation characteristics are calculated by HFSS 7.0 software, and compared with the experimental results. Experimental results show that the return loss is less than -10dB over the band of 1766MHz to 1900 MHz(134MHz) and the size of the fabricated microstrip patch antenna are $23\times20\times6.35mm$.