• 제목/요약/키워드: First forward difference

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복잡한 FLIR 영상에서의 소형 표적 탐지 기법 (Small Target Detection Method under Complex FLIR Imagery)

  • 이승익;김주영;김기홍;구본호
    • 한국멀티미디어학회논문지
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    • 제10권4호
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    • pp.432-440
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    • 2007
  • 본 논문에서는 복잡한 배경을 가지는 전방 관측 열상(FLIR; forward looking infrared) 영상에서의 소형 표적 탐지 기법을 제안하였다. 제안한 기법에서는 먼저 이전 프레임과 현재 프레임의 차를 구하여 표적의 움직임 정보를 획득할 뿐만 아니라 시간적으로 발생하는 배경 잡음을 제거한다. 이때 먼 거리에서 다가오는 표적이나 속도가 느린 표적의 경우 차 영상 내에서의 표적의 움직임 정보는 매우 작은 명암도 값을 가진다. 이런 작은 명암도 값을 두드러지게 하여 표적 탐지를 용이하게 하기 위하여 프레임 차 영상에 국부 감마교정을 행한다. 이렇게 표적이 개선된 영상에서 국부적인 통계적인 특성을 이용하여 탐지 지표를 계산한 후 가장 낮은 탐지 지표 값을 탐지하고자하는 표적으로 선정한다. 실험을 통하여 제안한 기법이 표적의 탐지성능이 기존의 탐지기법보다 우수하였음을 확인하였다.

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노년 여성의 표준치수 설정에 관한 연구(I) -연령대별 체형특성 및 지역별 체형차- (Development of Standard Body Measurement for Elderly Women -Characteristics & Regional Difference of Body Dimensions-)

  • 이정임;주소령;남윤자;문지연
    • 한국의류학회지
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    • 제27권1호
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    • pp.88-99
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    • 2003
  • The body changes of the elderly women are the forward tilt of the neck and shoulder point shrinkage of the spinal column, and protrusive abdomen. Unfortunately, few data based on body measurements for elderly women existed and a few studies are limited to the body figure of the elderly women. If these changes are not applied to the manufacturing of the clothing, almost of the elderly women will be unfitted with their clothing. So to improve the fitting of the elderly women, it is necessary to use the standard size systems for elderly women. This report is the first study to develop the standard tables of body measurements to be used for improving the fit of garments and patterns for women aged 60 and older. This study drew from anthropometric measurements of 337 and photographic measurements of 276 women aged 60 and older. It described the protocol of anthropometric measurement, the comparison between the measured data and the data on which National anthropometric survey of Korea 1997 is based, and the development of body measurement standard tables for elderly women. And we also considered the regional difference of body dimensions in order to develop the national size standards for elderly women. Further study would include the classification of body dimensions and description of each figure type for sizing apparel of women aged 60 and older.

배낭 가방의 끈 길이 차이가 머리척추각도에 미치는 영향 (Effect of craniovertebral angle on length difference of backpack strap)

  • 이지은;강대한;박소현;이유진;윤슬기
    • 대한물리치료과학회지
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    • 제22권2호
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    • pp.29-36
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    • 2015
  • Purpose : the purpose of the study was to investigate the effect of craniovertebral angle on bag strap length change method : this study is aimed at twenties healthy adult for 30 persons (male-8, female-22) research participant attach marks on tragus and cervical7 participant did not carry bag in First test. thereafter we take a picture mark point and measure the angle. immediately the second experiment was designed to carry back on participant's iliac crest and to walk freely for five minutes. afterward, we take a picture mark point and measure the angle. last experiment was performed after five minutes break. participants carried back on 10cm below participant's iliac crest and third experiment was performed the same way. results : Increase the length of the bag, craniovertebral angle is reduced and there is a significant difference between the three experiments.(p=.000) conclusion : when hold the back too long, Cervical spine cause temporary head forward posture. so carry on bag short.

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목뼈 가동 운동과 머리목 굽힘 운동이 만성 목통증 환자의 동적균형과 보행변인에 미치는 영향: 무작위 임상시험 (Effects of Cervical Mobilization and Craniocervical Flexion Exercise on the Dynamic Balance and Gait Variability in Chronic Neck Pain Patients: Randomized Controlled Trial)

  • 최태석;유병호;이상빈
    • 대한물리의학회지
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    • 제15권2호
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    • pp.31-38
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    • 2020
  • PURPOSE: The aim of this study is to find a more efficient intervention method through a study of the gait variables and dynamic balance of chronic neck pain patients. METHODS: Forty subjects aged between 40 and 60 years were allocated randomly to two groups; The first group performed PA (Posteroanterior Mobilization), and the second group conducted CCF (Craniocervical Flexion Exercise). The gait variability measured the speed, cadence, and dynamic balance in the forward, leftward, rightward, and rearward directions. An independent t-test, Wilcoxon signed-rank test, and paired t-test were used for statistical analysis. RESULTS: In the dynamic balance measurements, the variability of PA (p < .000) and CCF (p < .000) in the rightward direction, PA (p < .004) in leftward direction and forward direction increased significantly (p < .013). In an analysis of the gait variability, the cadence increased significantly in the PA group (p < .022) and not significantly in the CCF group (p < .056). On the other hand, there was no increase in the speed variable, in the PA group (p < .437). In the CCF group, the cadence increased significantly (p < .022). The differences in the PA and CCF group differences were not significant. CONCLUSION: The PA group showed a significant increase in the forward (p < .013), leftward (p < .004), and rightward directions (p < .000). Speed was significant in the CCF group, and cadence was significant in the PA group. The dynamic Balance was effective in the rightward direction in both groups, but there was no significant difference between the two groups.

지반침하지역에서의 탄성파 굴절법 탐사 적용사례 (Case Study on the Seismic Refraction Survey in a Subsidence Area)

  • 윤상호;지준;이두성
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2000년도 가을 학술발표회 논문집
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    • pp.577-584
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    • 2000
  • Seismic refraction survey was peformed for 10 lines along NE-SW and NW-SE directions above Nampoong gallery at Makyo-ri, Dogye, Samcheok, Kangwon-do. 48 geophones were laid in line with the interval of 1m, and a 5Kg hammer was used as a source at 5 points for each line. Data processing was done using reciprocal time method, GRM, and traveltime tomography which utilizes wavefront expansion method for forward process and SIRT for inversion. The result shows that the first layer has its lower boundary between 3.49m and 8.88m. The P-wave velocity of the first and the second layer were estimated as 270 360m/s and 1550 1940m/s respectively. When the boundary of the first and second layer is smooth enough and the velocity difference is large enough, GRM has little advantage over reciprocal time method. The result of reciprocal method and traveltime tomography shows consistency. The northeast part of the boundary has syncline structure, which is similar to the topography above. This implies that the collapse of the cavities of Nampoong gallery result in the subsidence of the ground surface. The subsidence is in progress across the Youngdong railroad, therefore a proper reinforcement work is required.

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LTE 시스템 채널 추정치의 후처리 기법 연구 (A Study on the Postprocessing of Channel Estimates in LTE System)

  • 유경렬
    • 전기학회논문지
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    • 제60권1호
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    • pp.205-213
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    • 2011
  • The Long Term Evolution (LTE) system is designed to provide a high quality data service for fast moving mobile users. It is based on the Orthogonal Frequency Division Multiplexing (OFDM) and relies its channel estimation on the training samples which are systematically built within the transmitting data. Either a preamble or a lattice type is used for the distribution of training samples and the latter suits better for the multipath fading channel environment whose channel frequency response (CFR) fluctuates rapidly with time. In the lattice-type structure, the estimation of the CFR makes use of the least squares estimate (LSE) for each pilot samples, followed by an interpolation both in time-and in frequency-domain to fill up the channel estimates for subcarriers corresponding to data samples. All interpolation schemes should rely on the pilot estimates only, and thus, their performances are bounded by the quality of pilot estimates. However, the additive noise give rise to high fluctuation on the pilot estimates, especially in a communication environment with low signal-to-noise ratio. These high fluctuations could be monitored in the alternating high values of the first forward differences (FFD) between pilot estimates. In this paper, we analyzed statistically those FFD values and propose a postprocessing algorithm to suppress high fluctuations in the noisy pilot estimates. The proposed method is based on a localized adaptive moving-average filtering. The performance of the proposed technique is verified on a multipath environment suggested on a 3GPP LTE specification. It is shown that the mean-squared error (MSE) between the actual CFR and pilot estimates could be reduced up to 68% from the noisy pilot estimates.

불도우저에 의한 개간 공법의 개선과 숙지화에 관한 연구 (Study on the Improvement of Land Clearing Methods by Bulldozer & Fertilization of Cleared Soil)

  • 황은
    • 한국농공학회지
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    • 제17권1호
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    • pp.3627-3641
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    • 1975
  • The Government is trying to increase total food grain yield to meet national self sufficiency by means of increasing unit yield as well as extending crop land, and this year he set the target of 321,000 hectare of forest to clear for cropping. This study was carried to investigate the most efficient method of clearing hillock by bulldozer, and successful method to develope yielding potential of newly cleared land in short term. Since the conventional land clearing method is just earth leveling and root removing neglecting top soil treatment, the growth of crop was poor and farmer tends not to care the land. The top-soil-furrowing method is applied through out this study, that is advantageous especially for the land having shallow top soil and low fertility like Korean forest. In this study, various operating method were tried to find out most efficient method separately in connection with the land slope less than 25 percent and over, and several fertilizing methods to develop yielding potential. The results are as follows; 1) For the natural land slope utilization method, applicable to the land having less than 25 percent slope, reverse operating was more efficient than using forward gear of bulldozer. The operating time was 3 hour 32 minutes and 36 seconds using forward gear was 2 hour 32 minutes and 30 seconds for reverse gear operation per 1,000 square meter. 2) Bulldozer having angle blade adjustment needed 7hr 15min. for constructing of terrace per 10a compaire with the one having angle & tilt adjustment needed 6hr 4min for same operations. Specially there is significant difference for operation time of first period (earth cutting) such as bulldozer having angle blade adjustment needed 3hr 56min compaired with the one having angle & tilt adjustment 3hr 59min. In construction of terrace, the bull-dozer having tilting and angle blade adjustment was most suitable and performed efficiently. 3) For the fertilizer application treatment, the grass (Ladino clover) yield in first year was almost same as ordinary field's in the plot applied(N.P.K+lime+manure) while none fertilizer plot showed one tenth of it, and (N.P.K.+lime) applied plot yielded on third. 4) The effect of different land clearing method to yield showed significant difference between each treatment especially in the first year, and the conventional method was the lowest. In the second year, still conventional terracing plot yielded only half of ordinary field while the other plots showed as same as ordinary field's. 5) The downward top soil treatment plot showed most rapid improvement in soil structure during one year physio chemically, it showed increase in pH rate and organic composition, and the soil changed gradually from loam to sand-loam and the moisture content increased against the pF rate, and it gives good condition to grow hay due to the increase of field water capacity with higher available water content. 6) Since the soil of tested area was granite, the rate of soil errosion was increased about 2 to 5 percent influencing in soil structure more sand reducing clay content, and an optimum contour farming method should be prepared as a counter measure of errosion.

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정.역구동 페달링에 따른 자전거 등판 시의 근전도 분석 (Electromyographic Analysis of a Uphill Propulsion of a Bicycle by Forward.Backward Pedaling)

  • 신응수;김현중
    • 한국운동역학회지
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    • 제18권4호
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    • pp.171-177
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    • 2008
  • 본 논문에서는 자전거의 언덕 등판 시 페달릴 방향이 근육의 활성도에 미치는 영향을 분석하였다. 이를 위하여 정역구동이 가능한 특수유성기어와 언덕 경사각에 따른 마찰력을 후륜에 인가할 수 있는 자기제동장치가 장착된 자전거로 실험 장치를 구성하고 3차원 동작분석과 근전도 분석을 수행하였다. 근활성도는 장단지근, 대퇴사두근, 전경골근, 비장근에 대해서 측정하였으며 언덕 경사는 $0^{\circ}$에서 $6^{\circ}$까지 변화시켰다. 근전도 신호는 우선 평균제곱법을 적용하여 25 ms마다 평균값을 구하고 50개의 연속된 주기에 대한 ensemble 곡선을 구하여 분석하였다. 그 결과로부터 페달링 방향의 변화는 자전거 주행 속도 및 인체하지 근육의 활성도에 큰 영향을 미치는 것을 확인하였다. 구체적으로는 크랭크 각도에 따른 근활성도의 패턴 및 최대값의 분포에 있어 정방향 구동과 역방향 구동은 큰 차이를 보이는데 근활성도의 최대값은 정구동으로 페달링할 때가 역 구동으로 페달링할 때보다 큰 반면 근활성도의 평균값은 장단지근과 대퇴사두근에서는 정구등 페달링이 더 높게 나타나고 전경골근과 비장근에서는 역구동 페달링이 더 높게 나타나며 주행 등판각이 증가하면 페달링 방향이 바뀜에 따른 근활성도 최대값의 차이는 더욱 커진다.

Alpha center를 이용한 전기비저항 수치 모델링 : 현장 탐사 자료에 대한 적용 예 (Numerical Resistivity Modeling Using Alpha Center Theory: A Case History for Field Resistivity Data)

  • 윤왕중
    • 터널과지하공간
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    • 제7권4호
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    • pp.334-340
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    • 1997
  • Alpha center theory which was first proposed by Stefanescu has been proved to be effective for the detection of the location of the conductive orebody. A numerical forward modeling was conducted to verify the effectiveness of this method. Field works were carried out along the three profiles in two different areas for the purpose of finding fractured zone which might be accompanied with the presence of the groundwater. And the results were modeled by alpha center method, which was later testified by wellproven 2-dimensional finite difference inversion scheme. Field data could be successfully modeled with this alpha center algorithm, especially for the smooth-varying resistivity models. For the abrupt change of the resistivity values, the alpha center coefficients have a tendency to be negative to simulate the steep resistivity gradients. This method is quite simple and easy for the future applications. The numerical calculation can be performed very quickly with the personal computers.

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A HIGHER ORDER NUMERICAL SCHEME FOR SINGULARLY PERTURBED BURGER-HUXLEY EQUATION

  • Jiwrai, Ram;Mittal, R.C.
    • Journal of applied mathematics & informatics
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    • 제29권3_4호
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    • pp.813-829
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    • 2011
  • In this article, we present a numerical scheme for solving singularly perturbed (i.e. highest -order derivative term multiplied by small parameter) Burgers-Huxley equation with appropriate initial and boundary conditions. Most of the traditional methods fail to capture the effect of layer behavior when small parameter tends to zero. The presence of perturbation parameter and nonlinearity in the problem leads to severe difficulties in the solution approximation. To overcome such difficulties the present numerical scheme is constructed. In construction of the numerical scheme, the first step is the dicretization of the time variable using forward difference formula with constant step length. Then, the resulting non linear singularly perturbed semidiscrete problem is linearized using quasi-linearization process. Finally, differential quadrature method is used for space discretization. The error estimate and convergence of the numerical scheme is discussed. A set of numerical experiment is carried out in support of the developed scheme.