• Title/Summary/Keyword: Local Coherence

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A Research on BCI using Coherence between EEG and EMG (EEG와 EMG의 Coherence을 이용한 BCI 연구)

  • Kim, Young-Joo;Whang, Min-Cheol;Kang, Hee
    • Journal of the Ergonomics Society of Korea
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    • v.27 no.2
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    • pp.9-14
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    • 2008
  • Coherence can be used to evaluate the functional cortical connections between the motor cortex and muscle. This study is to find coherence between EEG (electroencephalogram) and EMG (electromyogram) evoked by movement of a hand. Seven healthy participants were asked to perform thirty repetitive movement of right hand for ten seconds with rest for ten seconds. Specific feature of EEG components has been extracted by ICA (independent component analysis) and coherence between EEG and EMG was analyzed from data measured EEG in five local areas around central part of head and EMG in flexer carpri radialis muscle during grabbing movement. Coherence between EEG and EMG was successfully obtained at 0.025 confidence limit during hand movement and showed significant difference between rest and movement at 13-18Hz.

Motion Map Generation for Maintaining the Temporal Coherence of Brush Strokes in the Painterly Animation (회화적 애니메이션에서 브러시 스트로크의 시간적 일관성을 유지하기 위한 모션 맵 생성)

  • Park Youngs-Up;Yoon Kyung-Hyun
    • Journal of KIISE:Computer Systems and Theory
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    • v.33 no.8
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    • pp.536-546
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    • 2006
  • Painterly animation is a method that expresses painterly images with a hand-painted appearance from a video, and the most crucial element for it is the temporal coherence of brush strokes between frames. A motion map is proposed in this paper as a solution to the issue of maintaining the temporal coherence in the brush strokes between the frames. A motion map is the region that frame-to-frame motions have occurred. Namely, this map refers to the region frame-to-frame edges move by the motion information with the motion occurred edges as a starting point. In this paper, we employ the optical flow method and block-based method to estimate the motion information. The method that yielded the biggest PSNR using the motion information (the directions and magnitudes) acquired by various methods of motion estimation has been chosen as the final motion information to form a motion map. The created motion map determine the part of the frame that should be re-painted. In order to express painterly images with a hand- painted appearance and maintain the temporal coherence of brush strokes, the motion information was applied to only the strong edges that determine the directions of the brush strokes. Also, this paper seek to reduce the flickering phenomenon between the frames by using the multiple exposure method and the difference map created by the difference between images of the source and the canvas. Maintenance of the coherence in the direction of the brush strokes was also attempted by a local gradient interpolation to maintain the structural coherence.

EEG Signal Compression by Multi-scale Wavelets and Coherence analysis and denoising by Continuous Wavelets Transform (다중 웨이브렛을 이용한 심전도(EEG) 신호 압축 및 연속 웨이브렛 변환을 이용한 Coherence분석 및 잡음 제거)

  • 이승훈;윤동한
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.41 no.3
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    • pp.221-229
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    • 2004
  • The Continuous Wavelets Transform project signal f(t) to "Time-scale"plan utilizing the time varied function which called "wavelets". This Transformation permit to analyze scale time dependence of signal f(t) thus the local or global scale properties can be extracted. Moreover, the signal f(t) can be reconstructed stably by utilizing the Inverse Continuous Wavelets Transform. In this paper, the EEG signal is analyzed by wavelets coherence method and the De-noising procedure is represented.

Automatic fingerprint recognition using directional information in wavelet transform domain (웨이블렛 변환 영역에서의 방향 정보를 이용한 지문인식 알고리즘)

  • 이우규;정재호
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.10
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    • pp.2317-2328
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    • 1997
  • The objective of this paper is to develop an algorithm for a real-time automatic fingerprint recognition system. The algorithm employs the wavelet transform(WT) and the dominat local orientation that derived from the gradient Gaussian(GoG) and coherence in determining the directions of ridges in fingerprint images. By using the WT, the algorithm does not require conventional preprocessing procedures such as smothing, binarization, thining and restoration. For recognition, two fingerprint images are compared in three different ST domains;one that represents the original image compressed to quarter(LL), another that shows vertical directional characteristic(LH), and third as the block that contains horizontal direction(HL) in WT domain. Each block has dominat local orientation that derived from the GoG and coherence. The proposed algorithm is imprlemented on a SunSparc-2 workstation under X-window environment. Our simulation results, in real-time have shown that while the rate of Type II error-Incorrect recognition of two identical fingerprints as the identical fingerprints-is held at 0%, the rate of Type I error-Incorrect recognitionof two identical fingerprints as the different ones-is 2.5%.

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The Study of the Object Replication Management using Adaptive Duplication Object Algorithm (적응적 중복 객체 알고리즘을 이용한 객체 복제본 관리 연구)

  • 박종선;장용철;오수열
    • Journal of the Korea Society of Computer and Information
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    • v.8 no.1
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    • pp.51-59
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    • 2003
  • It is effective to be located in the double nodes in the distributed object replication systems, then object which nodes share is the same contents. The nodes store an access information on their local cache as it access to the system. and then the nodes fetch and use it, when it needed. But with time the coherence Problems will happen because a data carl be updated by other nodes. So keeping the coherence of the system we need a mechanism that we managed the to improve to improve the performance and availability of the system effectively. In this paper to keep coherence in the shared memory condition, we can set the limited parallel performance without the additional cost except the coherence cost using it to keep the object at the proposed adaptive duplication object(ADO) algorithms. Also to minimize the coherence maintenance cost which is the bi99est overhead in the duplication method, we must manage the object effectively for the number of replication and location of the object replica which is the most important points, and then it determines the cos. And that we must study the adaptive duplication object management mechanism which will improve the entire run time.

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The Structural Relationship among Sense of Coherence, Clinical Practice Stress, and Departmental Satisfaction of Dental Hygiene Students (치위생(학)과 학생의 통합성, 임상실습스트레스, 학과만족도의 구조적 관계)

  • Jeon, Ki Ha;Lim, Soon Ryun;Kim, Mi
    • Journal of dental hygiene science
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    • v.16 no.5
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    • pp.323-330
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    • 2016
  • The purpose of this study was to understand the comprehensive relationship among sense of coherence, clinical practice stress, and major satisfaction of students in the department of dental hygiene. From four local universities, departments of dental hygiene were selected: two departments represented a three-year curriculum system and two represented a four-year curriculum system. Data from the final questionnaires of 319 students were analyzed. Differences between variables were analyzed using t-tests and ANOVAs, and correlations were checked using Pearson's correlation coefficients. Path analysis was conducted to analyze the relationship among clinical practice stress, sense of coherence, and major satisfaction. The results indicated that clinical practice stress had a negative influential relationship with both sense of coherence, and major satisfaction. In addition, sense of coherence had a positive influential relationship with major satisfaction. The direct and indirect effects among factors displayed significant differences, indicating that clinical practice stress has a partial mediation effect on sense of coherence and major satisfaction. Therefore, major satisfaction can be increased by developing and implementing programs to improve sense of coherence.

Blood Vessel Enhancement by Directed Diffusion

  • Intajag, S.;Tipsuwanporn, V.
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.101-106
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    • 2004
  • In this paper, a blood vessel in an angiographic image, which plays an importance role in the diagnose diseases including in the eyes, brain and heart, is enhanced by using a directed diffusion technique. A fundamental component of the angiographic analysis is vessel segmentation that the proposed method provides a preprocessing of the image into a form suitable for human analysis, or more importantly, for machine analysis such the segmentation. Vessel enhancement is a challenging problem due to the complex nature of vascular trees and to imaging imperfections. Some parts of the inherent imperfections in angiography are the intensity inhomogeneity between the larger and smaller vessels, and another imperfection is the leakage of contrast agent into the background tissue that provides to low contrast between vessels and tissue. In the proposed scheme, the directed diffusion solves the problem by formulating a local geometric structure, which consists of direction and scale of the blood vessels. The diffusion process uses the local structure to enhance by a diffusivity tensor. The proposed algorithm can be applied to maintain sharpness and coherence-smooth the intra-regions into homogeneity better than traditional diffusion methods, which are Gaussian regulation and coherence enhancing diffusion.

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Formal Verification of RACE Protocol Using VIS (VIS를 이용한 RACE 포로토콜의 정형검증)

  • Um, Hyun-Sun;Choi, JIn-Young;Han, Woo-Jong;Ki, An-Do;Shim, Kyu-Hyun
    • The Transactions of the Korea Information Processing Society
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    • v.7 no.7
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    • pp.2219-2228
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    • 2000
  • Caches in a multiprocessing environment introduce the cache coherence problem. When multiple processors maintain locally cached copies of a unique shared-memory location, any local modification of the location can result in a globally inconsistent view of memory. Cache coherence protocols are important to operate a shared-memory multiprocessor system with efficiency and correctness. Since random testing and simulations are not enough to validate correctness of protocols, it is necessary to develop efficient and reliable verification methods. In this appear we present our experience in using VIS (Verification Interacting with Synthesis), a tool of formal method, to analyze a number of property of a cache coherence protocol, RACE (Remote Access Cache coherent Enforcement).

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Accurate Evaluation of Polarization Characteristics in the Integrated Optic Chip for Interferometric Fiber Optic Gyroscope Based on Path-matched Interferometry

  • Choi, Woo-Seok;Jo, Min-Sik
    • Journal of the Optical Society of Korea
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    • v.13 no.4
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    • pp.439-444
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    • 2009
  • Accurate evaluation of polarization characteristics in the integrated optic chip (IOC) for interferometric fiber optic gyroscope was performed. Spatial distribution of optical wavetrains caused by the polarization parameters such as local polarization cross-coupling and polarization rejection coefficient of the IOC were measured utilizing the path-matched optical coherence domain polarimetry (PM-OCDP). With the analytic model deduced from Jones matrix representation, we could accurately identify the polarization characteristics of the IOC. Both degree of measurement error due to the imperfect equipment conditions in PM-OCDP and birefringence of IOC chip were also characterized.

Solvent-localized in-situ NMR Monitoring by Intermolecular Single-quantum Coherence Study

  • Cha, Jin Wook;Park, Sunghyouk
    • Journal of the Korean Magnetic Resonance Society
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    • v.24 no.4
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    • pp.96-103
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    • 2020
  • A new NMR method to monitor solvent-localized NMR signals in the two-phase liquid system is suggested. This method based on intermolecular single-quantum coherence (iSQC). Here, we exploited the feature of the local action of distant dipolar field (DDF) effect in order to filter out specific NMR signals dissolved in different solvents. This solvent specific iSQC spectroscopy was carried out on a model two-phase liquid system (D-glucose in water/palmitic acid in chloroform), and showed solvent-localized NMR signals. We believe our approaches might be useful in metabolic analysis such as two-phase liquid extraction scheme for labile chemical species.