• Title/Summary/Keyword: Gradient-based Method

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Evaluation of Cerebral Cortices Associated with Sexual Arousal in Healthy Male Using BOLD-based Functional MRI

  • Kim, Hyung-Joong;Seo, Jeong-Jin;Kang, Heoung-Keun;Jeong, Gwang-Woo;Park, Jin-Gyoon;Jeong, Yong-Yeon;Chung, Tae-Woong;Woong Yoon;Park, Kwang-Sung
    • Proceedings of the KSMRM Conference
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    • 2001.11a
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    • pp.137-137
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    • 2001
  • Purpose: The purpose of this study was to identify cerebral cortices related with sexual arousal fro visual sexual stimulation in healthy males using BOLD-based functional MR imaging Method: Sixteen male volunteers with sexually potent(mean age:24) were examined for thi study. Functional MRI was performed on a 1.5T MR scanner(GE Signa Horizon) with birdcage-type head coil. In this study, blood oxygenation level dependent(BOLD) technique was utilized to create fMR image reflecting local brain activities. The BOLD-based fMRI d were obtained from 7 oblique planes using gradient-echo EPI with $90^{\circ}$flip angle, 50ms TE 6000ms TR, $26cm{\times}26$ cm FOV, $128{\times}128$ matrix, and 10mm slice thickness. The sexual stimulation paradigm consisted of two alternating periods of rest and activati and it began with a 1 minute rest, followed by a 2 minute stimulation by a documentary a erotic video film. Brain activation maps were generated by cross-correlation of imag acquired during rest and activation periods. The index of activation was used to compare t number of pixels activated by each task in each volunteer, where the significance of th differences was evaluated by using Students t-test.

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Prediction of the Flight Times of Hydrochara affinis and Sternolophus rufipes in Paddy Fields Based on RCP 8.5 Scenario (RCP 8.5 기후변화 시나리오를 적용한 논 서식 애물땡땡이 (Sternolophus rufipes)와 잔물땡땡이(Hydrochara affinis)의 비행시기 예측)

  • Choi, Soon-Kun;Kim, Myung-Hyun;Choe, Lak-Jung;Eo, Jinu;Bang, Hea-Son
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.18 no.1
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    • pp.16-29
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    • 2016
  • The total area of paddy field was estimated to be 55 % of the cultivated lands in South Korea, which is approximately 1 million hectares. Organisms inhabiting paddy fields if they are sensitive to environmental changes can be environmental indicator of paddy fields. Biological indicators such as phenology and distributional range are evaluated as intuitive and quantitative method to analyze the impact of climate change. This study aims to estimate flight time change of Hydrophilidae species' based on the RCP 8.5 climate change scenario. Unmanned monitoring systems were installed in Haenam, Buan, Dangjin and Cheorwon relative to the latitudinal gradient. In the three regions excepting Cheorwon, it was able to measure the abundance of flying Hydrochara affinis and Sternolophus rufipes. Degree-day for the flight time was determined based either on field measurement values and estimates of 2020s, 2050s and 2080s from KMA climate change scenario data. As a result, it is found that date of both species of initial flight becomes 15 days earlier, that of peak flight becomes 22 days earlier and that of final flight does 27 days earlier in 2080s compared to 2020s. The climate change impact on flight time is greater in coastal area, rural area and valley than inland area, urban area and plan. H. affinis and S. rufipes can be used as climate change indicator species.

Studies on Development of Prediction Model of Landslide Hazard and Its Utilization (산지사면(山地斜面)의 붕괴위험도(崩壞危險度) 예측(豫測)모델의 개발(開發) 및 실용화(實用化) 방안(方案))

  • Ma, Ho-Seop
    • Journal of Korean Society of Forest Science
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    • v.83 no.2
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    • pp.175-190
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    • 1994
  • In order to get fundamental information for prediction of landslide hazard, both forest and site factors affecting slope stability were investigated in many areas of active landslides. Twelve descriptors were identified and quantified to develop the prediction model by multivariate statistical analysis. The main results obtained could be summarized as follows : The main factors influencing a large scale of landslide were shown in order of precipitation, age group of forest trees, altitude, soil texture, slope gradient, position of slope, vegetation, stream order, vertical slope, bed rock, soil depth and aspect. According to partial correlation coefficient, it was shown in order of age group of forest trees, precipitation, soil texture, bed rock, slope gradient, position of slope, altitude, vertical slope, stream order, vegetation, soil depth and aspect. The main factors influencing a landslide occurrence were shown in order of age group of forest trees, altitude, soil texture, slope gradient, precipitation, vertical slope, stream order, bed rock and soil depth. Two prediction models were developed by magnitude and frequency of landslide. Particularly, a prediction method by magnitude of landslide was changed the score for the convenience of use. If the total store of the various factors mark over 9.1636, it is evaluated as a very dangerous area. The mean score of landslide and non-landslide group was 0.1977 and -0.1977, and variance was 0.1100 and 0.1250, respectively. The boundary value between the two groups related to slope stability was -0.02, and its predicted rate of discrimination was 73%. In the score range of the degree of landslide hazard based on the boundary value of discrimination, class A was 0.3132 over, class B was 0.3132 to -0.1050, class C was -0.1050 to -0.4196, class D was -0.4195 below. The rank of landslide hazard could be divided into classes A, B, C and D by the boundary value. In the number of slope, class A was 68, class B was 115, class C was 65, and class D was 52. The rate of landslide occurrence in class A and class B was shown at the hige prediction of 83%. Therefore, dangerous areas selected by the prediction method of landslide could be mapped for land-use planning and criterion of disaster district. And also, it could be applied to an administration index for disaster prevention.

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A Study on Risk Assessment Method for Earthquake-Induced Landslides (지진에 의한 산사태 위험도 평가방안에 관한 연구)

  • Seo, Junpyo;Eu, Song;Lee, Kihwan;Lee, Changwoo;Woo, Choongshik
    • Journal of the Society of Disaster Information
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    • v.17 no.4
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    • pp.694-709
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    • 2021
  • Purpose: In this study, earthquake-induced landslide risk assessment was conducted to provide basic data for efficient and preemptive damage prevention by selecting the erosion control work before the earthquake and the prediction and restoration priorities of the damaged area after the earthquake. Method: The study analyzed the previous studies abroad to examine the evaluation methodology and to derive the evaluation factors, and examine the utilization of the landslide hazard map currently used in Korea. In addition, the earthquake-induced landslide hazard map was also established on a pilot basis based on the fault zone and epicenter of Pohang using seismic attenuation. Result: The earthquake-induced landslide risk assessment study showed that China ranked 44%, Italy 16%, the U.S. 15%, Japan 10%, and Taiwan 8%. As for the evaluation method, the statistical model was the most common at 59%, and the physical model was found at 23%. The factors frequently used in the statistical model were altitude, distance from the fault, gradient, slope aspect, country rock, and topographic curvature. Since Korea's landslide hazard map reflects topography, geology, and forest floor conditions, it has been shown that it is reasonable to evaluate the risk of earthquake-induced landslides using it. As a result of evaluating the risk of landslides based on the fault zone and epicenter in the Pohang area, the risk grade was changed to reflect the impact of the earthquake. Conclusion: It is effective to use the landslide hazard map to evaluate the risk of earthquake-induced landslides at the regional scale. The risk map based on the fault zone is effective when used in the selection of a target site for preventive erosion control work to prevent damage from earthquake-induced landslides. In addition, the risk map based on the epicenter can be used for efficient follow-up management in order to prioritize damage prevention measures, such as to investigate the current status of landslide damage after an earthquake, or to restore the damaged area.

Splitting between Region of Chromatic and Achromatic by Brightness and Chroma (명암과 채도에 의한 색상영역과 비색상영역의 분할)

  • Kwak, Nae-Joung;Hwang, Jae-Ho
    • The Journal of the Korea Contents Association
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    • v.10 no.7
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    • pp.107-114
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    • 2010
  • Color is a sense signal for human to perceive being through light, and the color is divided into chromatic color and achromatic color. Chromatic color has hue, intensity, and saturation, but achromatic color has only intensity among the properties of chromatic color and doesn't have hue and saturation. Therefore it is important to split colors of image into area for human to perceive colors and not to perceive ones based on vision of human being. In this paper, we find a function to split colors of image into chromatic region of chromatic color region and achromatic region of achromatic color region. First, the input image of RGB color space is converted into the image of HSI color space in consideration of human vision and get a binary image from the converted image. After then, a function to split colors into ROC(ROC: Region of chromatic.) and ROA(ROA:Region of achromatic) is yield. It is difficult to split color of a general image into ROC and ROA. Therefore, to get the chromatic area and achromatic area, we make gradient images to have all range of intensity and range of saturation and to have a little range of hue and yield the function. The evaluation is tested using subjective-quality by 50 non-experts for result images of test images and general images. The results of the proposed method get better 27.5~32.96% than these of the conventional method

Performance Enhancement of Algorithms based on Error Distributions under Impulsive Noise (충격성 잡음하에서 오차 분포에 기반한 알고리듬의 성능향상)

  • Kim, Namyong;Lee, Gyoo-yeong
    • Journal of Internet Computing and Services
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    • v.19 no.3
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    • pp.49-56
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    • 2018
  • Euclidean distance (ED) between error distribution and Dirac delta function has been used as an efficient performance criterion in impulsive noise environmentsdue to the outlier-cutting effect of Gaussian kernel for error signal. The gradient of ED for its minimization has two components; $A_k$ for kernel function of error pairs and the other $B_k$ for kernel function of errors. In this paper, it is analyzed that the first component is to govern gathering close together error samples, and the other one $B_k$ is to conduct error-sample concentration on zero. Based upon this analysis, it is proposed to normalize $A_k$ and $B_k$ with power of inputs which are modified by kernelled error pairs or errors for the purpose of reinforcing their roles of narrowing error-gap and drawing error samples to zero. Through comparison of fluctuation of steady state MSE and value of minimum MSE in the results of simulation of multipath equalization under impulsive noise, their roles and efficiency of the proposed normalization method are verified.

Gibberellin A7 production by Aspergillus tubingensis YH103 and cultural characteristics of endophytic fungi isolated from Tetragonia tetragonoides in Dokdo islands (독도 번행초에서 분리된 내생균류의 배양적 특성과 Aspergillus tubingensis YH103의 gibberellin A7의 생산)

  • You, Young-Hyun;Park, Jong Myong;Lim, Sung Hwan;Kang, Sang-Mo;Park, Jong-Han;Lee, In-Jung;Kim, Jong-Guk
    • Korean Journal of Microbiology
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    • v.52 no.1
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    • pp.32-39
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    • 2016
  • Coastal plant species Tetragonia tetragonoides (Pall.) Kuntze native to the Dokdo islands was sampled and then 17 endophytic fungi were purely isolated based on morphological differences. The fungal isolates were characterized by their growth properties under NaCl concentration or pH gradient. Culture filtrates of the 17 fungal isolates were treated to Waito-c rice (WR) seedlings for verifying plant growth-promoting activity. As the results, YH103 strain showed the highest plant growth-promoting activity among them. Phylogenetic analysis of the isolates was done by the maximum likelihood method based on partial internal transcribed spacer region (ITS region: contaning ITS1, 5.8S, and ITS2), beta-tubulin (BenA), and calmodulin (CaM) gene sequences. Chromatographic analysis of the strain YH103 culture filtrate showed the existence of gibberellins ($GA_4$, $GA_7$, $GA_8$, and $GA_{19}$). Finally, the strain YH103 was identified as Aspergillus tubingensis by microscopic observation and molecular analysis and, to our knowledge, this is the first report of GAs producing A. tubingensis.

3D Medical Image Segmentation Using Region-Growing Based Tracking (영역 확장 기반 추적을 이용한 3차원 의료 영상 분할 기법)

  • Ko S.;Yi J.;Lim J.;Ra J. B.
    • Journal of Biomedical Engineering Research
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    • v.21 no.3 s.61
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    • pp.239-246
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    • 2000
  • In this paper. we propose a semi-automatic segmentation algorithm to extract organ in 3D medical data by using a manually segmentation result in a sing1e slice. Generally region glowing based tracking method consists of 3 steps object projection. seed extraction and boundary decision by region growing. But because the boundary between organs in medical data is vague, improper seeds make the boundary dig into the organ or extend to the false region. In the proposed algorithm seeds are carefully extracted to find suitable boundaries between organs after region growing. And the jagged boundary at low gradient region after region growing is corrected by post-processing using Fourier descriptor. Also two-path tracking make it possible to catch up newly appeared areas. The proposed algorithm provides satisfactory results in segmenting 1 mm distance kidneys from X-rav CT body image set of 82 slices.

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A Value Analysis of Ecological Restoration Construction Considering Life Cycle Cost and Performance - Focusing on the Wet Media for Slope Revegetation - (생애주기비용과 성능을 고려한 생태복원 공법 가치분석 - 습식 비탈면 기반재를 사례로 -)

  • Li, Lan;Kim, Sung Hee;Kim, Bo Heui;Lim, Su Hyun;Kim, Sung Il;Koo, Bon Hak
    • Journal of the Korean Institute of Landscape Architecture
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    • v.42 no.5
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    • pp.101-109
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    • 2014
  • In order to save costs and enhance quality in construction without damaging the environment, the VE/LCC analysis method is increasingly used. This study was carried out to conduct a value analysis for the ecological restoration of a slope considering life cycle cost and performance. The construction conditions were classified into three types(A, B, C) according to the condition of each base. Three construction methods for slope ecological restoration were selected by each condition. Eventually, a value analysis was conducted for total nine conditions by analyzing the life cycle cost and performance. The gradient of slope and base of Condition 1 were below 1:1.2 and general soil, while condition 2 and 3 were below 1:1.0(reaping rock) and below 1:0.7(soft rock, blasted rock), respectively. A value analysis was conducted based on the value estimated via life cycle cost and performance analysis. The result showed that the B construction method had the highest value in Condition 1 as it showed 108.4, while A and C showed 90.3 and 45.8, respectively. When it comes to Condition 2, Construction Method A indicated the highest value as it showed 89.1(B: 47.5, C: 47.0). In Condition 3, Construction Method A(89.1) was the highest, while B and C showed 55.4 and 40.2, respectively. Based on the result of this study, in order to make a reasonable decision that can enhance quality and reduce costs in slope ecological restoration, the slope ecological restoration method must be reviewed in consideration of life cycle cost and performance.

Grain-Size Trend Analysis for Identifying Net Sediment Transport Pathways: Potentials and Limitations (퇴적물 이동경로 식별을 위한 입도경향 분석법의 가능성과 한계)

  • Kim, Sung-Hwan;Rhew, Ho-Sahng;Yu, Keun-Bae
    • Journal of the Korean Geographical Society
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    • v.42 no.4
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    • pp.469-487
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    • 2007
  • Grain-Size Trend Analysis is the methodology to identify net sediment transport pathways, based on the assumption that the movement of sediment from the source to deposit leaves the identifiable spatial pattern of mean, sorting, and skewness of grain size. It can easily be implemented with low cost, so it has great potentials to contribute to geomorphological research, whereas it can also be used inadequately without recognition of its limitations. This research aims to compare three established methods of grain-size trend analysis to search for the adequate way of application, and also suggest the research tasks needed in improving this methodology 1D pathway method can corporate the field experience into analyzing the pathway, provide the useful information of depositional environments through X-distribution, and identify the long-term trend effectively. However, it has disadvantage of the dependence on subjective interpretation, and a relatively coarse temporal scale. Gao-Collins's 2D transport vector method has the objective procedure, has the capability to visualize the transport pattern in 2D format, and to identify the pattern at a finer temporal scale, whereas characteristic distance and semiquantitative filtering are controversial. Le Roux's alternative 2D transport vector method has two improvement of Gao-Collins's in that it expands the empirical rules, considers the gradient of each parameters as well as the order, and has the ability to identify the pattern at a finer temporal scale, while the basic concepts are arbitrary and complicated. The application of grain sire trend analysis requires the selection of adequate method and the design of proper sampling scheme, based on the field knowledge of researcher, the temporal scale of sediment transport pattern targeted, and information needed. Besides, the relationship between the depth of sample and representative temporal scale should be systematically investigated in improving this methodology.