• Title/Summary/Keyword: Bishop

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Nonlinear Approximations Using Modified Mixture Density Networks (변형된 혼합 밀도 네트워크를 이용한 비선형 근사)

  • Cho, Won-Hee;Park, Joo-Young
    • Journal of the Korean Institute of Intelligent Systems
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    • v.14 no.7
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    • pp.847-851
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    • 2004
  • In the original mixture density network(MDN), which was introduced by Bishop and Nabney, the parameters of the conditional probability density function are represented by the output vector of a single multi-layer perceptron. Among the recent modification of the MDNs, there is the so-called modified mixture density network, in which each of the priors, conditional means, and covariances is represented via an independent multi-layer perceptron. In this paper, we consider a further simplification of the modified MDN, in which the conditional means are linear with respect to the input variable together with the development of the MATLAB program for the simplification. In this paper, we first briefly review the original mixture density network, then we also review the modified mixture density network in which independent multi-layer perceptrons play an important role in the learning for the parameters of the conditional probability, and finally present a further modification so that the conditional means are linear in the input. The applicability of the presented method is shown via an illustrative simulation example.

The Undrained Shear Strength Characteristics of Mixed Soil with Oyster Shells (굴패각 혼합토의 비배수 전단강도 특성)

  • 송영진;김기영;문홍득
    • Journal of the Korean Geotechnical Society
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    • v.19 no.6
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    • pp.7-14
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    • 2003
  • In this study, undrained shear test was performed$K_o$ consolidation in order to study the shear strength characteristics of oysters-marine clay mixtures for three mixed ratios(0%, 25% and 50%). And, in order to study shear strength characteristics of oysters-marine clay mixtures, three different effective vertical stresses(200, 300 and 400kPa) were applied for the $K_o$ consolidation tests. In addition three different axial strain rates(0.005%/min, 0.05%/min, 0.5%/min) were applied for the case of effective vertical stress, 300kPa. According to experimental results, the more mixed ratios were increased, the more deviator stress was increased by crushing effect of oysters particles. especially, when effective vertical stress is 300kPa and mixed ratio increase from 25% to 50%, Test shows the increase of shear strength. But axial strain rate was not effect on the undrained shear strength. In the comparison and analysis that are based on the values of tests on the oysters-marine clay mixtures and the Mayne & Bishop's empiric formula, the undrained shear strength ratio shows a similar pattern of the tests. But for the prediction of the coefficient of the pore water pressure, the value of empiric formula shows more overestimated than the values of the tests at 0%, mixture ratio.

An analysis of the trends of value research : Focused on mathematical values and mathematics educational values (가치 연구의 동향 분석: 수학적 가치와 수학 교육적 가치를 중심으로)

  • Pang, Jeong-Suk;Kim, Seung-Min
    • The Mathematical Education
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    • v.58 no.4
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    • pp.609-625
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    • 2019
  • While research projects and reports on values in mathematics education increased in the international community over the years, little has been known about the topic and research findings in South Korea. The purpose of this study was to analyze the trends of value research in mathematics education focused on the "mathematical values" and "mathematics educational values" as defined by Bishop (1996) through a systematic review of the literature. A total of 66 research papers related to value research were analyzed in terms of the following four areas: research period, projects, target research population, and research method. The results of this study showed that the value research that was carried out was project-driven. There was an increase in both the number of papers published and countries that were studied, which encouraged the continuous expansion of the field. Furthermore, the topic of mathematics educational values was studied more than mathematical values. It was also observed that the survey method, among others, was frequently used to explore mathematics educational values of middle school teachers. Finally, research methods related to the measurement of value were gradually refined over time. Based on these results, this paper describes implications to conduct and advance value research in South Korea in various aspects, including in the field of mathematics education.

Analysis of Slope Stability with Consideration of the Wetting Front and Groundwater Level During Rainfall (강우시 습윤전선 및 지하수위를 고려한 사면의 안정성 해석)

  • Song, Young-Suk;Hong, Won-Pyo
    • The Journal of Engineering Geology
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    • v.21 no.1
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    • pp.25-34
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    • 2011
  • We applied a slope-stability analysis method, considering infiltration by rainfall, to the construction site where an express highway is being extended. Slope stability analysis that considers infiltration by rainfall can be classified into three methods: a method that considers the downward velocity of the wetting front, a method that considers the upward velocity of the groundwater level, and a method that considers both of these factors. The results of slope stability analysis using $Bishop^{\circ}{\Phi}s$ simplified method indicate that the safety factor due to the downward velocity of the wetting front decreases more rapidly than that due to the upward velocity of the groundwater level. For the third of the above methods, the safety factor decreases more rapidly than for the other two methods. Therefore, slope stability during rainfall should be analyzed with consideration of both the downward velocity of the wetting front and the upward velocity of the groundwater level.

Constitutive Model for Unsaturated Soils Based on the Effective Stress (유효응력에 근거한 불포화토의 역학적 구성모델)

  • Shin, Ho-Sung
    • Journal of the Korean Geotechnical Society
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    • v.27 no.11
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    • pp.55-69
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    • 2011
  • The importance of unsaturated state in various geo-engineering problems has led to the advance of mechanical constitutive model emulating behavior of unsaturated soils in response to thermo-hydro-mechanical loading. Elasto-plastic mechanical constitutive model for unsaturated soil is formulated based on Bishop's effective stress. Effective stress and temperature are main variables in constitutive equation, and incremental formulation of constitutive relationship is derived to compute stress update and stiffness tensor. Numerical simulations involving coupled THM processes are conducted to discuss numerical stability and applicability of developed constitutive model: one-dimensional test, tri-axial compression test, and clay-buffering at high level radioactive waste disposal. Numerical results demonstrated that developed model can predict very complex behavior of coupled THM phenomena and is applicable to geo-engineering problems under various environmental conditions, as well as interpret typical behavior of unsaturated soils.

A Case Study on Behavior of High-Raised Reinforced Soil Wall (고성토 보강토옹벽의 거동에 관한 사례연구)

  • Cho, Sam-Deok;Lee, Kwang-Wu;Lee, Hoon-Yeon;Chang, Ki-Soo
    • Journal of the Korean Geosynthetics Society
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    • v.5 no.4
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    • pp.35-42
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    • 2006
  • This paper describes a field experience on geogrid-reinforced soil walls rising up to 29.5m in height. Since experiences of design and construction on very high-raised geogrid reinforced soil wall were limited, thorough design and construction management was performed for safe construction of the wall. Regarding design of the wall, both internal and external stabilities were examined based on the design guideline specified by FHWA and overall slope stability analyses were performed by using Bishop simplified method. Moreover, a series of instrumentations were performed. The results of instrumentation for two tiered reinforced soil wall showed that not only the deformations of both the wall face and the reinforcement but also the horizontal earth pressures acting on the wall facing were very small. These results indicate that the reinforced soil wall technology can be applied successfully for high-raised tiered wall more than 20m heights and FHWA design guideline is very conservative for that large wall.

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High Noise Density Median Filter Method for Denoising Cancer Images Using Image Processing Techniques

  • Priyadharsini.M, Suriya;Sathiaseelan, J.G.R
    • International Journal of Computer Science & Network Security
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    • v.22 no.11
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    • pp.308-318
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    • 2022
  • Noise is a serious issue. While sending images via electronic communication, Impulse noise, which is created by unsteady voltage, is one of the most common noises in digital communication. During the acquisition process, pictures were collected. It is possible to obtain accurate diagnosis images by removing these noises without affecting the edges and tiny features. The New Average High Noise Density Median Filter. (HNDMF) was proposed in this paper, and it operates in two steps for each pixel. Filter can decide whether the test pixels is degraded by SPN. In the first stage, a detector identifies corrupted pixels, in the second stage, an algorithm replaced by noise free processed pixel, the New average suggested Filter produced for this window. The paper examines the performance of Gaussian Filter (GF), Adaptive Median Filter (AMF), and PHDNF. In this paper the comparison of known image denoising is discussed and a new decision based weighted median filter used to remove impulse noise. Using Mean Square Error (MSE), Peak Signal to Noise Ratio (PSNR), and Structure Similarity Index Method (SSIM) metrics, the paper examines the performance of Gaussian Filter (GF), Adaptive Median Filter (AMF), and PHDNF. A detailed simulation process is performed to ensure the betterment of the presented model on the Mini-MIAS dataset. The obtained experimental values stated that the HNDMF model has reached to a better performance with the maximum picture quality. images affected by various amounts of pretend salt and paper noise, as well as speckle noise, are calculated and provided as experimental results. According to quality metrics, the HNDMF Method produces a superior result than the existing filter method. Accurately detect and replace salt and pepper noise pixel values with mean and median value in images. The proposed method is to improve the median filter with a significant change.

Segmentation of Mammography Breast Images using Automatic Segmen Adversarial Network with Unet Neural Networks

  • Suriya Priyadharsini.M;J.G.R Sathiaseelan
    • International Journal of Computer Science & Network Security
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    • v.23 no.12
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    • pp.151-160
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    • 2023
  • Breast cancer is the most dangerous and deadly form of cancer. Initial detection of breast cancer can significantly improve treatment effectiveness. The second most common cancer among Indian women in rural areas. Early detection of symptoms and signs is the most important technique to effectively treat breast cancer, as it enhances the odds of receiving an earlier, more specialist care. As a result, it has the possible to significantly improve survival odds by delaying or entirely eliminating cancer. Mammography is a high-resolution radiography technique that is an important factor in avoiding and diagnosing cancer at an early stage. Automatic segmentation of the breast part using Mammography pictures can help reduce the area available for cancer search while also saving time and effort compared to manual segmentation. Autoencoder-like convolutional and deconvolutional neural networks (CN-DCNN) were utilised in previous studies to automatically segment the breast area in Mammography pictures. We present Automatic SegmenAN, a unique end-to-end adversarial neural network for the job of medical image segmentation, in this paper. Because image segmentation necessitates extensive, pixel-level labelling, a standard GAN's discriminator's single scalar real/fake output may be inefficient in providing steady and appropriate gradient feedback to the networks. Instead of utilising a fully convolutional neural network as the segmentor, we suggested a new adversarial critic network with a multi-scale L1 loss function to force the critic and segmentor to learn both global and local attributes that collect long- and short-range spatial relations among pixels. We demonstrate that an Automatic SegmenAN perspective is more up to date and reliable for segmentation tasks than the state-of-the-art U-net segmentation technique.

Assessment of Carsington Dam Failure by Slope Stability and Dam Behavior Analyses (사면안정 해석과 댐 거동분석을 통한 Carsington Dam 파괴의 고찰)

  • 송정락;김성인
    • Proceedings of the Korean Geotechical Society Conference
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    • 1991.10a
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    • pp.87-102
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    • 1991
  • It has been reported that the failure of Carsington Dam in Eng1and occured due to the existence of a thin yellow clay layer which was not identified during the design work, and due to pre-existing shears of the clay layer. The slope stability analyses during the design work, which utilized traditional circular arc type failure method and neglected the existence of the clay layer, showed a safety factor of 1.4. However, the post-failure analyses which utilized translational failure mode considering the clay layer and the pre-existing shear deformation revealed the reduction of safety factor to unity. The post-failure analysis assumed 10。 inclination of the horizontal forces onto each slice based on the results of finite element analyses. In this paper, Bishop's simplified method, Janbu method, and Morgenstern-Price method were used for the comparison of both circular and translational failure analysis methods. The effects of the pre-existing shears and subsquent movement were also considered by varying the soil strength parameters and the pore pressure ratio according to the given soi1 parameters. The results showed factor of safefy 1.387 by Bishop's simplified method(STABL) which assumed circular arc failure surface and disregarding yellow clay layer and pre-failure material properties. Also the results showed factor of safety 1.093 by Janbu method(STABL) and 0.969 by Morgenstern-Price method(MALE) which assumed wedge failure surface and considerd yellow clay layer using post failure material properties. In addition, dam behavior was simulated by Cam-Clay model FEM program. The effects of pore pressure changes with loading and consolidation, and strength reduction near or at failure were also considered based on properly assumed stress-strain relationship and pore pressure characteristics. The results showed that the failure was initiated at the yellow clay layer and propagated through other zones by showing that stress and displacement were concentrated at the yel1ow clay layer.

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The Effectiveness of Arthroscopic Debridement with Mini-Open Ulnar Nerve Decompression in Primary Osteoarthritis of the Elbow with Ulnar Neuropathy (척골 신경 병증을 동반한 주관절 퇴행성 관절염에서 최소 절개 척골 신경 감압술과 동시에 시행한 관절경적 변연 절제술의 효과)

  • Jegal, Midum;Yu, Kun-Woong;Park, Sung-Bae;Kim, Jong-Pil
    • Journal of the Korean Orthopaedic Association
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    • v.52 no.1
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    • pp.15-24
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    • 2017
  • Purpose: The aim of this study was to determine the effectiveness of arthroscopic debridement with mini-open ulnar nerve decompression in primary osteoarthritis of the elbow with ulnar neuropathy. Materials and Methods: Between May of 2006 and July of 2014, a total of 43 patients who had undergone surgery for primary osteoarthritis of the elbow with ulnar neuropathy were included in this study. We divided the subjects into two groups according to the method of surgery: group 1 (n=18) received mini-open ulnar nerve decompression only, and group 2 (n=25) received arthroscopic debridement with mini-open ulnar nerve decompression. Patients were assessed for the following clinical outcomes: visual analogue scales (VAS) score, range of motion of the elbow joint, Mayo elbow performance score (MEPS), and disabilities of the arm, shoulder and hand (DASH) at the time before surgery and 6 months after surgery. We analyzed the recovery of the ulnar nerve by the McGowan grade and Bishop rating score preoperatively and at 6 months after the surgery. Results: The VAS score, range of motion of the elbow joint, MEPS, and DASH showed significant statistical difference after the surgery (p<0.05). However, between the 2 groups, there was no significant difference. For the McGowan grade, all cases of both groups-except one case each group-showed at least one grade improvement. Moreover, group 2 showed a greater significant difference than group 1 (p=0.001). At the final follow-up, according to the Bishop rating score, group 2 had a greater significant difference than group 1 (p=0.036). Conclusion: Arthroscopic debridement with mini-open ulnar nerve decompression in primary osteoarthritis of the elbow with ulnar neuropathy is a useful technique, which has several advantages, including the benefits associated with a minimally invasive surgery and also the improvement of elbow joint function and excellent recovery of the ulnar nerve.