• Title/Summary/Keyword: Multi-dimensional Space Analysis

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Development of Multi-dimensional Limiting Process for Multi-dimensional Compressible Flow (다차원 압축성 유동 해석을 위한 MLP 기법의 개발)

  • 윤성환;김종암;김규홍
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.7
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    • pp.1-11
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    • 2006
  • Through the analysis of conventional TVD limiters, a new multi-dimensional limiting function is derived for an oscillation control in multi-dimensional flows. Then, Multi-dimensional Limiting Process (MLP) is developed with the multi-dimensional limiting function. The major advantage of MLP is to prevent oscillations across a multi-dimensional discontinuity, and it is readily compatible with more than 3rd order spatial interpolation. Moreover, MLP shows a good convergence characteristic in a steady problem and it is very simple to be implemented. Through numerical test cases, it is verified that MLP substantially improves accuracy, efficiency and robustness both in continuous and discontinuous flows.

Label Embedding for Improving Classification Accuracy UsingAutoEncoderwithSkip-Connections (다중 레이블 분류의 정확도 향상을 위한 스킵 연결 오토인코더 기반 레이블 임베딩 방법론)

  • Kim, Museong;Kim, Namgyu
    • Journal of Intelligence and Information Systems
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    • v.27 no.3
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    • pp.175-197
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    • 2021
  • Recently, with the development of deep learning technology, research on unstructured data analysis is being actively conducted, and it is showing remarkable results in various fields such as classification, summary, and generation. Among various text analysis fields, text classification is the most widely used technology in academia and industry. Text classification includes binary class classification with one label among two classes, multi-class classification with one label among several classes, and multi-label classification with multiple labels among several classes. In particular, multi-label classification requires a different training method from binary class classification and multi-class classification because of the characteristic of having multiple labels. In addition, since the number of labels to be predicted increases as the number of labels and classes increases, there is a limitation in that performance improvement is difficult due to an increase in prediction difficulty. To overcome these limitations, (i) compressing the initially given high-dimensional label space into a low-dimensional latent label space, (ii) after performing training to predict the compressed label, (iii) restoring the predicted label to the high-dimensional original label space, research on label embedding is being actively conducted. Typical label embedding techniques include Principal Label Space Transformation (PLST), Multi-Label Classification via Boolean Matrix Decomposition (MLC-BMaD), and Bayesian Multi-Label Compressed Sensing (BML-CS). However, since these techniques consider only the linear relationship between labels or compress the labels by random transformation, it is difficult to understand the non-linear relationship between labels, so there is a limitation in that it is not possible to create a latent label space sufficiently containing the information of the original label. Recently, there have been increasing attempts to improve performance by applying deep learning technology to label embedding. Label embedding using an autoencoder, a deep learning model that is effective for data compression and restoration, is representative. However, the traditional autoencoder-based label embedding has a limitation in that a large amount of information loss occurs when compressing a high-dimensional label space having a myriad of classes into a low-dimensional latent label space. This can be found in the gradient loss problem that occurs in the backpropagation process of learning. To solve this problem, skip connection was devised, and by adding the input of the layer to the output to prevent gradient loss during backpropagation, efficient learning is possible even when the layer is deep. Skip connection is mainly used for image feature extraction in convolutional neural networks, but studies using skip connection in autoencoder or label embedding process are still lacking. Therefore, in this study, we propose an autoencoder-based label embedding methodology in which skip connections are added to each of the encoder and decoder to form a low-dimensional latent label space that reflects the information of the high-dimensional label space well. In addition, the proposed methodology was applied to actual paper keywords to derive the high-dimensional keyword label space and the low-dimensional latent label space. Using this, we conducted an experiment to predict the compressed keyword vector existing in the latent label space from the paper abstract and to evaluate the multi-label classification by restoring the predicted keyword vector back to the original label space. As a result, the accuracy, precision, recall, and F1 score used as performance indicators showed far superior performance in multi-label classification based on the proposed methodology compared to traditional multi-label classification methods. This can be seen that the low-dimensional latent label space derived through the proposed methodology well reflected the information of the high-dimensional label space, which ultimately led to the improvement of the performance of the multi-label classification itself. In addition, the utility of the proposed methodology was identified by comparing the performance of the proposed methodology according to the domain characteristics and the number of dimensions of the latent label space.

Signal Design of grouping Quasi-Orthogonal Space Time Block Codes on the Multi-dimensional Signal Space (다차원 신호 공간에서 그룹 준직교 시공간 블록 부호의 신호 설계)

  • Yeo, Seung-Jun;Heo, Seo-Weon;Lee, Ho-Kyoung
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.3
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    • pp.40-45
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    • 2008
  • This paper proposes the signal design techniques of quasi-orthogonal space time block codes (QO-STBCS) on the multi-dimensional signal space. In the multiple antenna system(MIMO), QO-STBC achieves the full-diversity and full-rate by grouping two based-symbols. We study the condition for the full-diversity of the grouping QO-STBC geometrically and the performance analysis of codes on the multi-dimensional signal space regarding the various signal constellations. Simulation results show that the way of the performance analysis is validity.

Analysis on Stable Grasping based on Three-dimensional Acceleration Convex Polytope for Multi-fingered Robot (3차원 Acceleration Convex Polytope를 기반으로 한 로봇 손의 안정한 파지 분석)

  • Jang, Myeong-Eon;Lee, Ji-Hong
    • Journal of Institute of Control, Robotics and Systems
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    • v.15 no.1
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    • pp.99-104
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    • 2009
  • This article describes the analysis of stable grasping for multi-fingered robot. An analysis method of stable grasping, which is based on the three-dimensional acceleration convex polytope, is proposed. This method is derived from combining dynamic equations governing object motion and robot motion, force relationship and acceleration relationship between robot fingers and object's gravity center through contact condition, and constraint equations for satisfying no-slip conditions at every contact points. After mapping no-slip condition to torque space, we derived intersected region of given torque bounds and the mapped region in torque space so that the intersected region in torque space guarantees no excessive torque as well as no-slip at the contact points. The intersected region in torque space is mapped to an acceleration convex polytope corresponding to the maximum acceleration boundaries which can be exerted by the robot fingers under the given individual bounds of each joints torque and without causing slip at the contacts. As will be shown through the analysis and examples, the stable grasping depends on the joint driving torque limits, the posture and the mass of robot fingers, the configuration and the mass of an object, the grasp position, the friction coefficients between the object surface and finger end-effectors.

Coupled Analysis of Thermo-Fluid-Flexible Multi-body Dynamics of a Two-Dimensional Engine Nozzle

  • Eun, WonJong;Kim, JaeWon;Kwon, Oh-Joon;Chung, Chanhoon;Shin, Sang-Joon;Bauchau, Olivier A.
    • International Journal of Aeronautical and Space Sciences
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    • v.18 no.1
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    • pp.70-81
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    • 2017
  • Various components of an engine nozzle are modeled as flexible multi-body components that are operated under high temperature and pressure. In this paper, in order to predict complex behavior of an engine nozzle, thermo-fluid-flexible multi-body dynamics coupled analysis framework was developed. Temperature and pressure on the nozzle wall were obtained by the steady-state flow analysis for a two-dimensional nozzle. The pressure and temperature-dependent material properties were delivered to the flexible multi-body dynamics analysis. Then the deflection and strain distribution for a nozzle configuration was obtained. Heat conduction and thermal analyses were done using MSC.NASTRAN. The present framework was validated for a simple nozzle configuration by using a one-way coupled analysis. A two-way coupled analysis was also performed for the simple nozzle with an arbitrary joint clearance, and an asymmetric flow was observed. Finally, the total strain result for a realistic nozzle configuration was obtained using the one-way and two-way coupled analyses.

A Study on the relationship between the multi dimensional integrative model of space experience and space design (공간 경험에 관한 다차원 통합모델과 공간디자인 조형간의 상관성에 관한 연구)

  • Lee, Ji-Young;Kwon, Young-Gull
    • Proceedings of the Korean Institute of Interior Design Conference
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    • 2004.11a
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    • pp.55-60
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    • 2004
  • This paper aims to provide a multi-dimensional integrative model that can give a comprehensive account for human space experience. Human space experience is too complicated phenomenon, so space designer need to understand about mechanism of space cognition. From psychological point of view, I analyze the mechanism that is based on emotional reaction. This model consist of three dimensions: sensory, reflexive, and reflective dimension. Assuming this model, we have attempt the typological analysis to the space by studying human space experience. Finally, the outcome provides how space designer use this effect for application of human experience.

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A MULTI-DIMENSIONAL REDUCTION METHOD OF LARGE-SCALE SURVEY DATABASE

  • Lee, Y.;Kim, Y.S.;Kang, H.W.;Jung, J.H.;Lee, C.H.;Yim, I.S.;Kim, B.G.;Kim, H.G.;Kim, K.T.
    • Publications of The Korean Astronomical Society
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    • v.28 no.1
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    • pp.7-13
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    • 2013
  • We present a multi-dimensional reduction method of the surveyed cube database obtained using a single- dish radio telescope in Taeduk Radio Astronomy Observatory (TRAO). The multibeam receiver system installed at the 14 m telescope in TRAO was not optimized at the initial stage, though it became more stabilized in the following season. We conducted a Galactic Plane survey using the multibeam receiver system. We show that the noise level of the first part of the survey was higher than expected, and a special reduction process seemed to be definitely required. Along with a brief review of classical methods, a multi-dimensional method of reduction is introduced; It is found that the 'background' task within IRAF (Image Reduction and Analysis Facility) can be applied to all three directions of the cube database. Various statistics of reduction results is tested using several IRAF tasks. The rms value of raw survey data is 0.241 K, and after primitive baseline subtraction and elimination of bad channel sections, the rms value turned out to be 0.210 K. After the one-dimensional reduction using 'background' task, the rms value is estimated to be 0.176 K. The average rms of the final reduced image is 0.137 K. Thus, the image quality is found to be improved about 43% using the new reduction method.

Preference Analysis for the Pedestrian Space in Large-scale Residential Complex by Multi Dimensional Scaling -Focused on the Haeundae New town in Busan- (다차원 척도법을 이용한 대규모 주거단지 보행공간의 선호도 분석 -부산광역시 해운대 신시가지를 대상으로-)

  • Kim, Yu Jun;Kang, Youn Won;Kim, Jong Gu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.1
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    • pp.333-340
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    • 2014
  • We analyzed pedestrian preference and features of preferential space by MDS (Multi Dimensional Scaling). As the result, features of pedestrian space in dimension 1 could be interpreted as "Segregation of Pedestrian and Vehicle", and features of pedestrian space in dimension 2 could be read like "Natural-City". And as a result of vector analysis about preferential of pedestrian, a pedestrian mall between housing complex, pedestrian space in pocket park, pedestrian space in neighborhood park, and pedestrian space around public facilities was the best preferential space. On the other hand, pedestrians tended to dislike pedestrian space between detached.

From Fragmented Development to Three-Dimensional and Coordinated Development - Research on Renewal Strategies of Existing Underground Commercial Space in Harbin

  • Xue, Minghui;Su, Yiming;Hu, Jiayu
    • International Journal of High-Rise Buildings
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    • v.10 no.1
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    • pp.17-28
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    • 2021
  • In Harbin, a network of underground commercial spaces has been developed to occupy spaces that were originally created as civil defense shelters. With the gradual extension of the local metro rail system, the existing underground commercial space is no longer an isolated regional development, but a space that represents "three-dimensional city" and coordinated development taking place in many Chinese cities. Based on the analysis of the unique development process taken in underground space of Harbin, this paper summarizes three characteristics of its early model of "fragmented development" of underground space. By conducting a comprehensive field research and survey, the researchers analyzed 472 questionnaires related to the development trend, and proposed multi-level synergistic elements for the renewal and development of underground commercial space. The paper concludes by discussing the trend of "three-dimensional and collaborative development," suitable for the development needs of the new era, and the corresponding development strategies for the renewal of underground space.

A study for the establishment of analysis tool for the visible area of three dimensional space - Based on the Raster operation using 3D game engine - (다시점 가시영역 분석도구설정에 관한 기초연구 - 3D게임엔진을 이용한 래스터 연산방식을 중심으로 -)

  • Kim, Suk-Tae;Jun, Han-Jong
    • Korean Institute of Interior Design Journal
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    • v.16 no.5
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    • pp.38-46
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    • 2007
  • In the late 1970s, the method of quantitative and scientific space structural analysis based on graph theory was introduced to the process of space design, which arranges design and functional elements, as relying heavily on intuition could produce errors due to unverified experiences and prejudices of the designer. As the method of space analysis is complex and hard to express visually and requires repetitive operations, it was discussed theoretically only. However, with the development of computer performance and graphic in recent years, visualization became possible. But the method of visual structural analysis of space is at the level of two dimensions and it is not easy to get accurate data when it is applied to limited three dimensional space such as an interior space. For the visual structural analysis of space, this study presents 4 indices including visibility volume level, pure visibility connection frequency, effective visibility connection frequency, and path visibility connection frequency. This study also presents space division using three dimensional arrangement rather than the existing vector operation method and raytracing algorithm at the lattice constant. Based on this, an analysis tool for the visible regions of three dimensional space that is capable of evaluating at multiple points by using three dimensional game engine and presentation tool that allows the analyzer to interpret the data effectively is made. It is applied to 2 prototype models by displacing Z axis, and the results are compared with UCL Depthmap to verify the validity of data and evaluate its usefulness as a multidimensional, multi-view space analysis tool.