• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.11
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• pp.1070-1077
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• 2011

This paper introduces a radar signal processing technique for intelligent rear view monitoring of an automobile. The linear frequency modulation-frequency shift keying(LFM-FSK) waveform, which is the combination of frequency modulation continuous wave(FMCW) and frequency shift keying(FSK) waveform, is employed to simultaneously estimate the range, relative aspect angle, and velocity of an automobile. Hence, it can be applied to monitor the rear view of an automobile. FMCW waveform has high range resolution capability, but it produces ghost targets under a multiple target environment. In contrast, FSK waveform can provide high velocity resolution and avoids the problem of ghost targets. However, it fails to identify multiple targets along the radar's line of sight. With LFM-FSK waveform, we can estimate the ranges and velocities of multiple targets with very high resolution, which avoids the ghost target problem of an FMCW waveform. Simulation result shows that LFM-FSK wavefrom is suitable for use in the lane change assistance system for an automobile.

• Ocean and Polar Research
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• v.26 no.3
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• pp.439-451
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• 2004

Total solar irradiance (750), total UV irradiunce (TUV) and erythemal UV irradiance (EUV) measured at King Sejong station $(62.22^{\circ}S,\;58.78^{\circ}W)$ in west Antarctica have been used together with total ozone, cloud amount and snow cover to examine the effects of ozone, cloud and snow surface on these surface solar inadiunce over the period of 1998-2003. The data of three solar components for each scan were grouped by cloud amount, n in oktas $(0{\leq}n<3,\;3{\leq}n<4,\;4{\leq}n<5,\;5{\leq}n<6,\;6{\leq}n<7\;and\;7{\leq}n<8)$ and plotted against solar zenith angle (SZA) over the range of $45^{\circ}\;to\;75^{\circ}$. The radiation amplification factor (RAE) is used to quantify ozone effect on EUV. RAF of EUV decreases from 1.51 to 0.94 under clear skies but increases from 0.94 to 1.85 under cloudy skies as SZA increases, and decreases from 1.51 to 1.01 as cloud amount increases. The effects of cloud amount and snow surface on EUV are estimated as a function of SZA and cloud amount after normalization of the data to the reference total ozone of 300 DU. In order to analyse the transmission of solar radiation by cloud, regression analyses have been performed for the maximum values of solar irradiance on clear sky conditions $(0{\leq}n<3)$ and the mean values on cloudy conditions, respectively. The maximum regression values for the clear sky cases were taken to represent minimum aerosol conditions fur the site and thus appropriate for use as a normalization (reference) factor for the other regressions. The overall features for the transmission of the three solar components show a relatively high values around SZAs of $55^{\circ}\;and\;60^{\circ}$ under all sky conditions and cloud amounts $4{\leq}n<5$ and $5{\leq}n<6$. The transmission is, in general, the largest in TUV and the smallest in EUV among the three components of the solar irradiance. If the ground is covered with snow on partly cloudy days $(6{\leq}n<7)$, EUV increases by 20 to 26% compared to snow-free surface around SZA $60^{\circ}-65^{\circ}$, due to multiple reflections and scattering between the surface and the clouds. The relative difference between snow surface and snow-free surface slowly increases from 9% to 20% as total ozone increases from 100 DU to 400 DU under partly cloud conditions $(3{\leq}n<6)$ at SZA $60^{\circ}$. The snow effects on TUV and TSO are relatively high with 32% and 34%, respectively, under clear sky conditions, while the effects changes to 36% and 20% for TUV and TSO, respectively, as cloud amount increases.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.1
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• pp.91-96
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• 2010

In this paper, a deformation measurement technology of the nuclear fuel rod is proposed. The deformation measurement system include high definition CCD or CMOS image sensor, lens, semiconductor laser line beam marker, and optical & mechanical accessories. The basic idea of the deformation measurement is to illuminate the outer surface of the fuel rod with collimated laser line beam at an angle of 45 degrees or higher. The relative motion of the fuel rod in the horizontal direction causes the illuminated laser line beam to move vertically along the surface of the fuel rod. The resulting change of laser line beam position in the surface of the fuel rod is imaged as the parabolic beam in the high definition CCD or CMOS image sensor. From the parabolic beam pattern, the ellipse model is extracted. And the slope of the long and the short axis of the ellipse model is found. The crossing point between the saddle point of the parabolic beam and the long & short axis of the ellipse model is taken as the feature of the deformed fuel rod. The vertical offset between feature points before and after fuel rod deformation is calculated. From the experimental results, $50\;{\mu}m$ inspection resolution is acquired using the proposed method, which is three times enhanced than the conventional criterion ($150\;{\mu}m$) of the guide for the inspection of the nuclear fuel rod.

• Journal of Environmental Impact Assessment
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• v.22 no.6
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• pp.547-556
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• 2013

Recently, golf courses have increased over the years because golf became popular leisure sport. Various environmental problems have been then issued by a golf course during constructing and running them. A problem of pesticide, which is serious among various environmental problems, from golf course has harmful effect on surrounding area and makes human suffer from acute and chronic diseases. Pesticides are used for the cost-effective managing of golf course and the amount of pesticides also increases as the number of golf course increase. Since the assessment of pesticides on near-by surrounding has been focused on water and soil media, studies related to atmospheric dispersion have been hardly attempted. The method to assess an impact of pesticide nearby agricultural production by the atmospheric dispersion using AGDISP(AGricultural DISPersal) model was developed and applied to the actual planned golf course located in Hongcheon, Gangwon. For implementing AGDISP, parameters were investigated from the golf course's land use planning map, pesticide spray device, Hong-Cheon weather station and etc. First of all, a kind of pesticide, a form of spraying pesticide, geographical features, weather data, and distance(golf course to plantation) were investigated to understand how to work these parameters in AGDISP. Restricted data(slope angle, droplet size distribution and solar insolation) sensitivity analysis of these parameters to estimate effect of pesticide nearby a plantation and a high relative contribution data of analyzed data was selected for input data. Ethoprophos was chosen as the pesticide used in the golf course and the amounts of pesticide deposition per annual agricultural productions were predicted. The results show that maximum amount of pesticide deposition through atmospheric dispersion was predicted $2.32{\mu}/m^2$ at 96 m where the nearest organic plantation exists. The residues of pesticide were also estimated based on the annul production of the organic and the deposition amount of the pesticide. Consequently, buckwheat, wheat and millet were likely to exceed maximum residue limits for pesticides in foods(MRL) and sorghum, corn and peanut were likely to exceed MRL by organic farming as well.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.1
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• pp.21-29
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• 2003

It is very important to reduce the computational time in estimating the parameters of vision control algorithm for robot's position control in real time. Unfortunately, the batch estimation commonly used requires too murk computational time because it is iteration method. So, the batch estimation has difficulty for robot's position control in real time. On the other hand, the Extended Kalman Filtering(EKF) has many advantages to calculate the parameters of vision system in that it is a simple and efficient recursive procedures. Thus, this study is to develop the EKF algorithm for the robot's vision control in real time. The vision system model used in this study involves six parameters to account for the inner(orientation, focal length etc) and outer (the relative location between robot and camera) parameters of camera. Then, EKF has been first applied to estimate these parameters, and then with these estimated parameters, also to estimate the robot's joint angles used for robot's operation. finally, the practicality of vision control scheme based on the EKF has been experimentally verified by performing the robot's position control.

• The Journal of the Korean bone and joint tumor society
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• v.3 no.1
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• pp.18-25
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• 1997

Prosthetic replacement is one of the most common methods of reconstruction after resection of malignant tumor around the knee. Gait analysis provides a relative objective data about the gait function of patients with prosthesis. The purpose of this study was to compare the gait pattern of the patients who underwent limb salvage surgery with prosthesis for distal femur and that of patients with prosthesis for proximal tibia. This study included ten patients (4 males, 6 females, mean age 22.7 years, range 14-36) who underwent a wide resection and Kotz hinged modular reconstruction prosthesis replacement and six normal adult(Control). The site of bone tumor was the distal femur (Group 1) in six patients and proximal tibia (Group 2) in 4 patients. The follow-up period ranged from 15 to 82 months (mean : 33 months). The evaluation consisted of clinical assessment, radiographic assessment, gait analysis using VICON 370 Motion Analysis System. The gait analysis included the linear parameters such as, walking velocity, cadence, step length, stride length, stance time, swing time, single support and double support time and the three-dimensional kinematics (joint rotation angle, velocity of joint rotation) of ankle, knee, hip and pelvis in sagittal, coronal and transverse plane. For the kinetic evaluation, the moment of force (unit: Nm/kg) and power (unit: Watt/kg) of ankle, knee and hip joint in sagittal, coronal and transverse plane. In the linear parameters, cadence, velocity, step time and single support were decreased in both group 1 and group 2 compared with control. Double support decreased in group 2 compared with control significantly(p<.05). In contrast to our hypothesis, there was no significant difference between group 1 and group 2. In Kinematics, we observed significant difference (p<.05) of decreased knee flexion in loading response (G2

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.556-562
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• 2009

Ectopic eruption of the maxillary first permanent molar means that the molar erupts out of the normal position and is arrested in its eruption by the second primary molar. This local eruption disturbance results in a premature atypical resorption on the distal part of the second primary molar. In most irreversible cases, the second primary molar is lost prematurely, either by spontaneous exfoliation or by extraction, In cases of doubt as to whether the eruption is of the irreversible type or not, careful radiographic observation period for a few months would be valuable in evaluating the possibilities of the tooth's freeing itself. The purpose of this study was to determine the characteristics and occurrence of the ectopic eruption of the maxillary first permanent molar. A descriptive, observational, retrospective study was done using the radiographs of 25 conseutive patients, who were in the first phase of mixed dentition. A method was designed to evaluate the amount of pathologic resorption of the second maxillary primary molar and the mesial angulation of the first permanent molar. The study showed that the most important etiologic factor was the eruption path or mesial angulation of the first permanent molars relative the chosen reference lines.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.552-557
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• 2020

The Radar Cross Section (RCS) is a virtual region indicating the strength of a wavelength at which a radar signal is reflected and received. As the ship's RCS represents its own stealth performance and survivability, efforts have been made in various areas from design to construction to reduce the RCS. The RCS can be predicted using design drawings and CAD models, but it is necessary to measure the RCS at sea since sea clutter and multipath reflections occur in the sea environment. However, such RCS predictions and measured values provide only a simple relative magnitude to the user, and there has not been much research on this topic. In this paper, a missile countermeasure technique was studied using 3D RCS measurement data in an operating environment. The elevation and azimuth angle of the ship viewed from the missile were estimated using the location information of the missile, and the RCS value was inverted by mapping it to previously measured 3D RCS measurement data. In addition, by using the movement information of the missile, the RCS observed by the missile could be predicted in advance, and this method can be used to propose a response plan based on the maneuvering and chaff system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.626-633
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• 2020

This study examined the behavior of the ground by comparing the methods using the results of the Terzaghi formula and the ground investigation data and method considering the dilatancy effect for a circular tunnel using the finite element method. In the case of the Terzaghi formula, the tunnel load can be overestimated and cause overdesign. The method using the results of the ground investigation data cannot be applied when a reasonable coefficient of earth pressure is not determined. This is because it behaves completely differently from the actual behavior, and unexpected problems can occur. In the case of the method considering the dilatancy effect, however, both the strength enhancement effect can be considered through the dilatancy angle and relative density. Therefore, the tunnel load was calculated most reasonably using the method considering dilatancy. Finite element analysis using the geotechnical survey results showed that the tensile stress acts at the top of the tunnel when the upper soil of the tunnel is shallow. On the other hand, additional verification is necessary, such as a comparison with the field measurement results. Through additional research, if normalized, the tunnel load can be calculated reasonably at the time of tunnel design, and safe and economical design is possible.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.1576-1581
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• 2013

In the present study, the performance of a PF heat exchanger for heat pump dryer was investigated. Capacity and dehumidification amount of the PF heat exchangers(PF1, PF2, PF3) by different inclination angles($0^{\circ}$, $30^{\circ}$, $60^{\circ}$) were studied. Experimental conditions were an air velocity crossing to the heat exchanger(0.5m/s), an air dry-bulb temperature($60^{\circ}C$) and relative humidity(70%). The experimental results have shown that the performance of the inclined PF heat exchangers was better than that of the vertically installed one. PF3 showed better performance compared to PF1 and PF2 due to the large pin pitch which are leading to more draining for dehumidified water. But, capacity and dehumidification amount of the PF heat exchanger at the inclination angles of $60^{\circ}$ was decreased due to pressure drop. Also, to predict the experimental data of the PF heat exchanger, the performance program was developed for the inclination angles of $0^{\circ}$. PF heat exchanger performance between experiment data and calculation data was satisfied within the maximum 2% for capacity and 3% for dehumidification amount.