• Title/Summary/Keyword: Coherence Time

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Research Trend Analysis for Fault Detection Methods Using Machine Learning (머신러닝을 사용한 단층 탐지 기술 연구 동향 분석)

  • Bae, Wooram;Ha, Wansoo
    • Economic and Environmental Geology
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    • v.53 no.4
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    • pp.479-489
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    • 2020
  • A fault is a geological structure that can be a migration path or a cap rock of hydrocarbon such as oil and gas, formed from source rock. The fault is one of the main targets of seismic exploration to find reservoirs in which hydrocarbon have accumulated. However, conventional fault detection methods using lateral discontinuity in seismic data such as semblance, coherence, variance, gradient magnitude and fault likelihood, have problem that professional interpreters have to invest lots of time and computational costs. Therefore, many researchers are conducting various studies to save computational costs and time for fault interpretation, and machine learning technologies attracted attention recently. Among various machine learning technologies, many researchers are conducting fault interpretation studies using the support vector machine, multi-layer perceptron, deep neural networks and convolutional neural networks algorithms. Especially, researchers use not only their own convolution networks but also proven networks in image processing to predict fault locations and fault information such as strike and dip. In this paper, by investigating and analyzing these studies, we found that the convolutional neural networks based on the U-Net from image processing is the most effective one for fault detection and interpretation. Further studies can expect better results from fault detection and interpretation using the convolutional neural networks along with transfer learning and data augmentation.

Comparison of Co-registration Algorithms for TOPS SAR Image (TOPS 모드 SAR 자료의 정합기법 비교분석)

  • Kim, Sang-Wan
    • Korean Journal of Remote Sensing
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    • v.34 no.6_1
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    • pp.1143-1153
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    • 2018
  • For TOPS InSAR processing, high-precision image co-registration is required. We propose an image co-registration method suitable for the TOPS mode by comparing the performance of cross correlation method, the geometric co-registration and the enhanced spectral diversity (ESD) matching algorithm based on the spectral diversity (SD) on the Sentinel-1 TOPS mode image. Using 23 pairs of interferometric pairs generated from 25 Sentinel-1 TOPS images, we applied the cross correlation (CC), geometric correction with only orbit information (GC1), geometric correction combined with iterative cross-correlation (GC2, GC3, GC4), and ESD iteration (ESD_GC, ESD_1, ESD_2). The mean of co-registration errors in azimuth direction by cross correlation and geometric matching are 0.0041 pixels and 0.0016 pixels, respectively. Although the ESD method shows the most accurate result with the error of less than 0.0005 pixels, the error of geometric co-registration is reduced to 0.001 pixels by repetition through additional cross correlation matching between the reference and resampled slave image. The ESD method is not applicable when the coherence of the burst overlap areas is low. Therefore, the geometric co-registration method through iterative processing is a suitable alternative for time series analysis using multiple SAR data or generating interferogram with long time intervals.

Hybrid CMA-ES/SPGD Algorithm for Phase Control of a Coherent Beam Combining System and its Performance Analysis by Numerical Simulations (CMA-ES/SPGD 이중 알고리즘을 통한 결맞음 빔 결합 시스템 위상제어 및 동작성능에 대한 전산모사 분석)

  • Minsu, Yeo;Hansol, Kim;Yoonchan, Jeong
    • Korean Journal of Optics and Photonics
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    • v.34 no.1
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    • pp.1-12
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    • 2023
  • In this study, we propose a hybrid phase-control algorithm for multi-channel coherent beam combining (CBC) system by combining the covariant matrix adaption evolution strategy (CMA-ES) and stochastic parallel gradient descent (SPGD) algorithms and analyze its operational performance. The proposed hybrid CMA-ES/SPGD algorithm is a sequential process which initially runs the CMA-ES algorithm until the combined final output intensity reaches a preset interim value, and then switches to running the SPGD algorithm to the end of the whole process. For ideal 7-channel and 19-channel all-fiber-based CBC systems, we have found that the mean convergence time can be reduced by about 10% in comparison with the case when the SPGD algorithm is implemented alone. Furthermore, we analyzed a more realistic situation in which some additional phase noise was introduced in the same CBC system. As a result, it is shown that the proposed algorithm reduces the mean convergence time by about 17% for a 7-channel CBC system and 16-27% for a 19-channel system compared to the existing SPGD alone algorithm. We expect that for implementing a CBC system in a real outdoor environment where phase noise cannot be ignored, the hybrid CMA-ES/SPGD algorithm proposed in this study will be exploited very usefully.

A Research on the Women's Costume on the Bigdata of Movie Napoleon

  • Weolkye KIM;Sangwon LEE
    • International Journal of Advanced Culture Technology
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    • v.12 no.3
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    • pp.21-28
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    • 2024
  • The public can access movies more easily than any other cultural genre. The film's costumes convey the social, political, and cultural climate of that time period. Additionally, it subtly conveys the message of the movie, including the intentions of the director and the characters. Filmmakers can now use fact-based materials to plan their films, and audiences can now watch costume in movies with objective standards, particularly in period dramas, thanks to the advancements in over-the-top (OTT) services. The 77th British Academy costume Award went to the movie Napoleon because of how much emphasis it placed on the outfit. Ninety-five percent of the costume was made by experts in military uniforms and costumery. In contrast to the previous aristocratic and exaggerated Rococo costume, Napoleonic clothing had a natural and common-class character. A natural-shaped Chemise dress composed of light, reflective material first appeared in the Directoire era, just after the French Revolution. Chemise dresses made of a variety of materials gained popularity during the Empire era. With Napoleon taking the throne and Josephine becoming the empress, the vibrant court culture resurfaced during the Empire era. The silk was embellished with gold thread and embroidery, train dangling forms, and different types of sleeves appeared in Empire styles. They wore Pellisse and shawls under the coat. The hair style had long, ancient hair and was adorned with fillets. They also wore straw hats, bonnets, and caps. Long gloves and parasols were also popular accessories, as were pearl or colored jewelry necklaces, earrings, bracelets, and rings. During the Empire era, tiaras were fashionable. Shoes were either low-heeled pumps or sandals. The movie uses Chemise and Empire costumes, which are versatile enough to be used in a range of settings and eras. When it came to details, the type of sleeve was employed without regard to time, such as when using those from an earlier or later period. Since jewelry was worn more often than not in that era, practically every character has earrings on their necklaces. Nearly exact replicas of the coronation costume can be found in paintings by Jacques-Louis David. The red trains, Josephine's Empire dress, the crown, the Tiara, and the costumes of every character in attendance were all clearly identifiable in terms of form and color. To further aid viewers in understanding and enhancing the film's overall coherence, a scene featuring David drawing the coronation was added. Overall, there were differences in that the historical costumes were accurately recreated, the materials and details were utilized without restriction, and some of the costumes were designed with modern materials or accessories that were used more than the historical costumes. This section appears to have been written to highlight the beauty of the characters' personalities or settings. There is a limitation to this study in that it only looked at aristocratic clothing, which includes Josephine's. We will concentrate on male clothing in future research.

Designing a Writing Support System Based on Narrative Comprehension of Readers (독자의 내러티브 이해를 반영한 창작 지원 시스템 설계)

  • Kwon, Hochang;Kwon, Hyuk Tae;Yoon, Wan Chul
    • Journal of the HCI Society of Korea
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    • v.9 no.2
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    • pp.23-31
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    • 2014
  • A variety of writing support systems focus on the information management or the feature analysis of the commercially successful narrative texts. In these approaches, the reader's role in the narrative creating process is overlooked. During a writing work, an author anticipates the reader's response or expectation to the narrative and he/she organizes the narrative either along or against the prediction about readers. Assessing and controlling the reader's comprehension in the development of events influences the aesthetic quality of the narrative. In this paper, we suggest a writing support system to visualize and adjust the characteristics of a narrative text related to the reader's comprehension, which is theoretically based on the narrative structure model and the event-indexing situation model. Under the development of the support system, we designed an interactive framework to create events as the basic units of story and arrange them onto both story- and discourse-time axes. Using this framework, we analyzed the organization of events about an actual film narrative. We also proposed both the continuity of the situational dimensions and the cognitive complexity as the characteristics to affect the reader's comprehension, hence we devised a method to visualize and evaluate them. This method was applied to the actual film narrative and the result was discussed in the aspect of the features of the narrative and wiring support strategies.

A survey on the topic introductory materials of the 7th grade mathematics textbooks and its usages - Centered on the 6th and 7th curriculum based textbooks - (수학과 7-가 교과서 단원도입 활동의 내용소재 변화 및 활용실태 조사 연구 -제 6차와 7차 교과서를 중심으로-)

  • 이영하;김미연
    • School Mathematics
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    • v.4 no.3
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    • pp.375-399
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    • 2002
  • When a curriculum change is being an issue, the editorships and the promotive directions reflect to supplement the social requests. However it is often criticized that such changes in the textbook itself are not satisfactory enough as to coherent to the editoships. And we set the following research questions; (1) One of the most important changes in the new 7th curriculum is to encourage the students' activities. We checked if it is well suited in the new textbooks. (2) Often textbook itself is not important In class, while instructor or students want something else other than the one suggested in the textbook. We asked 187 teachers how they use the textbooks in class. To answer (1), we checked up the introductory - activity - contents with 7 categories, which are ${\circled1}$ of real life sources ${\circled2}$ in use of concrete manipulative ${\circled3}$ in use of computers or calculators ${\circled4}$ in use of historical resources ${\circled5}$ stimulating to recall a relevant previous knowledges ${\circled6}$ of coherence between the activity and the exploratory contexts. ${\circled2}$ were increased, rewarding to the decrease of ${\circled5}$, in the new textbooks, while changes in ${\circled3}$ and ${\circled4}$ were not enough to talk about increments. Especially slight decrease in ${\circled6}$ were detected and it seemed to attribute to the unmatchable use of ${\circled1}$ and ${\circled2}$ with the explanation of mathematical subjects, which also implies how difficult to match ${\circled1}$ and ${\circled2}$ with ${\circled6}$. Analyzing the reponses of (2), about 70% of the teachers used the introductory activities in the textbook, which led better attention of sudents, while 30% of teachers do not use it because they felt that its inroductory activities had not been adequate for their purposes. Teachers counted inadequacy reasons for not being helpful in class, lack of time or lack of support of students, etc. Those teachers use introductory activities invented of their own for classes. As some results of the study, we suggest firstly that authors of textbooks have to get more informations to provide ways to entcourage students' interest in mathematics classes. The ways must be practical and brain storming as well as More use of computers and calculators and mathematical history are expected. Secondly, we are emphasizing the feedbacks between the textbook authors and the users(teachers and students) through internet. Which, we anticipate, will get better communications between them and be a good foundations of continuous modifications of textbooks.

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Real-Time Hierarchical Techniques for Rendering of Translucent Materials and Screen-Space Interpolation (반투명 재질의 렌더링과 화면 보간을 위한 실시간 계층화 알고리즘)

  • Ki, Hyun-Woo;Oh, Kyoung-Su
    • Journal of Korea Game Society
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    • v.7 no.1
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    • pp.31-42
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    • 2007
  • In the natural world, most materials such as skin, marble and cloth are translucent. Their appearance is smooth and soft compared with metals or mirrors. In this paper, we propose a new GPU based hierarchical rendering technique for translucent materials, based on the dipole diffusion approximation, at interactive rates. Information of incident light, position, normal, and irradiance, on the surfaces are stored into 2D textures by rendering from a primary light view. Huge numbers of pixel photons are clustered into quad-tree image pyramids. Each pixel, we select clusters (sets of photons), and then we approximate multiple subsurface scattering term with the clusters. We also introduce a novel hierarchical screen-space interpolation technique by exploiting spatial coherence with early-z culling on the GPU. We also build image pyramids of the screen using mipmap and pixel shader. Each pixel of the pyramids is stores position, normal and spatial similarity of children pixels. If a pixel's the similarity is high, we render the pixel and interpolate the pixel to multiple pixels. Result images show that our method can interactively render deformable translucent objects by approximating hundreds of thousand photons with only hundreds clusters without any preprocessing. We use an image-space approach for entire process on the GPU, thus our method is less dependent to scene complexity.

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Study of Relationship Between Illness Perception and Delay in Seeking Help for Breast Cancer Patients Based on Leventhal's Self-Regulation Model

  • Attari, Seyedeh Maryam;Ozgoli, Giti;Solhi, Mahnaz;Majd, Hamid Alavi
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.sup3
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    • pp.167-174
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    • 2016
  • One of the major causes of morbidity and mortality in breast cancer patients is delay in seeking help. Leventhal's self-regulation model provides an appropriate framework to assess delay in seeking help. The aim of this study was to investigate the relationship between "illness perception" and "help seeking delay" in breast cancer patients based on Leventhal's self-regulation model. In this correlational descriptive study with convenience sampling conducted in 2013, participants were 120 women with breast cancer who were diagnosed in the last year and referred to chemotherapy and radiotherapy centers in Rasht, Iran. Data collection scales included demographic data, Revised Illness Perception Questionnaire (IPQ-R)and a researcher made questionnaire to measure the delay in seeking help. Pre-hospital delay (help seeking delay) was evaluated in 3 phases (assessment, disease, behavior). The data were analyzed using SPSS-19. The mean (SD) age calculated for the patients was $47.3{\pm}10.2$. Some 43% of the patients had a high school or higher education level and 82% were married. The "pre-hospital delay" was reported ${\geq}3months$. Logistic regression analysis showed that none of the illness perception components were correlated with appraisal and behavioral delay phases. In the illness delay phase, "time line" (p-value =0.04) and "risk factors"(p-value=0.03) had significant effects on reducing and "psychological attributions" had significant effects on increasing the delay (p-value =0.01). "Illness coherence" was correlated with decreased pre-hospital patient delay (p-value<0.01). Women's perceptions of breast cancer influences delay in seeking help. In addition to verifying the validity of Leventhal's self-regulation model in explaining delay in seeking help, the results signify the importance of the "illness delay phase" (decision to seek help) and educational interventions-counseling for women in the community.

An Analysis of Current States and Curriculums of Interior Design Major at Vocational High Schools and Suggestions for Improvement (실업계 고등학교 실내디자인전공 활성화를 위한 교육현장의 실태와 교과내용 분석)

  • 김대년;오혜경;천진희
    • Journal of the Korean Home Economics Association
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    • v.39 no.12
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    • pp.1-14
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    • 2001
  • The purpose of this study was to analyze the current states of interior design as a major at vocational high schools and to suggest ways in which it can be improved. Three hundred and four students and twelve teachers of two vocational high schools comprised the sample population for this study. Data was collected using two methods, questionnaires and interviews. Frequency distribution, mean, and chi-square tests were used to analyze the data. The findings of this study are as follows: The student respondents were more interested in studying residential design, furniture design and making, drafting and perspective drawing than other areas of study. Most teachers had difficulties teaching the subject of residential design because they were not well educated with this area. Surprisingly most students hoped to extend their education to a university or college after graduation, not to enter the workforce. According to teachers'responses, almost ninety percentage of students entered university or college. And more than two thirds of the students desired to study an interior design related major at the university level. Among graduates having jobs, half of them were working in interior design fields. If the students had to choose their jobs, they would work in interior design fields. The variables differentiating several related careers after graduation were school, grade, and sex. The students viewed interior design, interior coordination, and CAD related work as fields likely to enter upon graduating from vocational high schools; however, teachers viewed furniture making, interior accessorizing, and home fashion as fields more appropriate to the students'level of training. The teacher respondents criticized the textbooks in four categories; suitability with the students'level was average or below average; students'interest level and students'understanding level were average or above average; and whether the book was easy or difficult to be utilized for the purposes of teaching was also average or above average. The criticism was a little diverse depending on each book or each chapter. The teachers pointed out several problems using those books, such as insufficient examples or explanation, lack of coherence between some chapters, and an incompatibility with the allotted time frame in class. The merits of the textbooks varied such as a well organized structure, ability to generate students'interest. This study revealed that the strategy for improving the interior design major at vocational high schools should invoke, 1) dividing students into two groups-one to enter a university; the other to have jobs after graduation to focus their interests. 2) improving textbooks more appropriate to the students. 3) providing present teachers the opportunities for in-service training and hiring new teachers with credentials more suitable to educate students who desire to be interior designers.

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Performance Evaluation of Underwater Acoustic Communication in Frequency Selective Shallow Water (주파수 선택적인 천해해역에서 수중음향통신 성능해석)

  • Park, Kyu-Chil;Park, Jihyun;Lee, Seung Wook;Jung, Jin Woo;Shin, Jungchae;Yoon, Jong Rak
    • The Journal of the Acoustical Society of Korea
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    • v.32 no.2
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    • pp.95-103
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    • 2013
  • An underwater acoustic (UWA) communication in shallow water is strongly affected by the water surface and the seabed acoustical properties. Every reflected signal to receiver experiences a time-variant scattering in sea surface roughness and a grazing-angle-dependent reflection loss in bottom. Consequently, the performance of UWA communication systems is degraded, and high-speed digital communication is disrupted. If there is a dominant signal path such as a direct path, the received signal is modeled statistically as Rice fading but if not, it is modeled as Rayleigh fading. However, it has been known to be very difficult to reproduce the statistical estimation by real experimental evaluation in the sea. To give an insight for this scattering and grazing-angle-dependent bottom reflection loss effect in UWA communication, authors conduct experiments to quantify these effects. The image is transmitted using binary frequency shift keying (BFSK) modulation. The quality of the received image is shown to be affected by water surface scattering and grazing-angle-dependent bottom reflection loss. The analysis is based on the transmitter to receiver range and the receiver depth dependent image quality and bit error rate (BER). The results show that the received image quality is highly dependent on the transmitter-receiver range and receiver depth which characterizes the channel coherence bandwidth.