• Title, Summary, Keyword: kernel

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A note on nonparametric density deconvolution by weighted kernel estimators

  • Lee, Sungho
    • Journal of the Korean Data and Information Science Society
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    • v.25 no.4
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    • pp.951-959
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    • 2014
  • Recently Hazelton and Turlach (2009) proposed a weighted kernel density estimator for the deconvolution problem. In the case of Gaussian kernels and measurement error, they argued that the weighted kernel density estimator is a competitive estimator over the classical deconvolution kernel estimator. In this paper we consider weighted kernel density estimators when sample observations are contaminated by double exponentially distributed errors. The performance of the weighted kernel density estimators is compared over the classical deconvolution kernel estimator and the kernel density estimator based on the support vector regression method by means of a simulation study. The weighted density estimator with the Gaussian kernel shows numerical instability in practical implementation of optimization function. However the weighted density estimates with the double exponential kernel has very similar patterns to the classical kernel density estimates in the simulations, but the shape is less satisfactory than the classical kernel density estimator with the Gaussian kernel.

Speaker Identification Using Greedy Kernel PCA (Greedy Kernel PCA를 이용한 화자식별)

  • Kim, Min-Seok;Yang, Il-Ho;Yu, Ha-Jin
    • MALSORI
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    • no.66
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    • pp.105-116
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    • 2008
  • In this research, we propose a speaker identification system using a kernel method which is expected to model the non-linearity of speech features well. We have been using principal component analysis (PCA) successfully, and extended to kernel PCA, which is used for many pattern recognition tasks such as face recognition. However, we cannot use kernel PCA for speaker identification directly because the storage required for the kernel matrix grows quadratically, and the computational cost grows linearly (computing eigenvector of $l{\times}l$ matrix) with the number of training vectors I. Therefore, we use greedy kernel PCA which can approximate kernel PCA with small representation error. In the experiments, we compare the accuracy of the greedy kernel PCA with the baseline Gaussian mixture models using MFCCs and PCA. As the results with limited enrollment data show, the greedy kernel PCA outperforms conventional methods.

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THE RELATION BETWEEN THE BERGMAN KERNEL AND THE SZEGO KERNEL

  • Jeong, Moon-Ja
    • Journal of the Korean Mathematical Society
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    • v.33 no.2
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    • pp.283-290
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    • 1996
  • We can expect a close relationship between the Bergman kernel and the Szego kernel of a domain because we can change boundary integrals to solid integrals via Green's identity.

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Sentry: a Binary-Level Interposition Mechanism for Kernel Extension (Sentry: Kernel Extension을 위한 바이너리 수준의 인터포지션 기법)

  • Kim Se-Won;Hwang Jae-Hyun;Yoo Hyuck
    • Proceedings of the Korean Information Science Society Conference
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    • pp.325-327
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    • 2006
  • 현재 사용되고 있는 운영체제들은 그들의 기능을 확장하거나 교체하기 위해서 kernel extension을 사용해 왔다. 일반적으로 이러한 kernel extension들은 커널과 같은 주소공간에서 실행하기 때문에, 그것에서 발생하는 오류(fault)로 인해 전체 시스템이 망가지는 결과를 초래할 위험이 있다. 그래서 kernel extension의 안전한 실행에 관한 연구들은 kernel extension에서 발생한 오류를 전체 시스템으로부터 고립시키는 것이 주목적이었다. 하지만 이러한 방법들은 kernel extension의 어셈블리어로 된 코드를 분석하거나 사용하고 있는 커널의 소스 코드를 수정을 필요로 한다. 본 논문은 Sentry라는 kernel extension을 감시하기 위한 인터포지션 서비스를 제안한다. Sentry를 사용하기 위해서 별도의 커널 코드를 수정할 필요도 없으며, 이미 사용하고 있는 리눅스와 호환될 수 있는 특징을 지니고 있다. 그리고 kernel extension의 소스코드 및 어셈블리 코드에 대한 분석 없이 바이너리 파일을 직접 수정하여 kernel extension을 모니터링 할 수 있도록 한다. 게다가 Sentry는 재구성이 가능하기 때문에 얼마든지 kernel extension에 대한 보호정책을 동적으로 바꿀 수 있다.

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Common Expression Extraction Using Kernel-Kernel pairs (커널-커널 쌍을 이용한 공통 논리식 산출)

  • Kwon, Oh-Hyeong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.7
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    • pp.3251-3257
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    • 2011
  • This paper presents a new Boolean extraction technique for logic synthesis. This method extracts kernel-kernel pairs as well as cokernel-kernel pairs. The given logic expressions can be translated into Boolean divisors and quotients with kernel-kernel pairs. Next, kernel intersection method provides the common sub-expressions for several logic expressions. Experimental results show the improvement in literal count over previous other extraction methods.

THE BERGMAN KERNEL FUNCTION AND THE SZEGO KERNEL FUNCTION

  • CHUNG YOUNG-BOK
    • Journal of the Korean Mathematical Society
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    • v.43 no.1
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    • pp.199-213
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    • 2006
  • We compute the holomorphic derivative of the harmonic measure associated to a $C^\infty$bounded domain in the plane and show that the exact Bergman kernel function associated to a $C^\infty$ bounded domain in the plane relates the derivatives of the Ahlfors map and the Szego kernel in an explicit way. We find several formulas for the exact Bergman kernel and the Szego kernel and the harmonic measure. Finally we survey some other properties of the holomorphic derivative of the harmonic measure.

Geometric Kernel for CAD/CAM Application Software Development (CAD/CAM 응용 소프트웨어 개발은 위한 형상 커널 개발)

  • 정연찬;박준철
    • Korean Journal of Computational Design and Engineering
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    • v.6 no.4
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    • pp.271-276
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    • 2001
  • A geometric kernel is the library of core mathematical functions that defines and stores 3D shapes in response to users'commands. We developed a light geometric kernel suitable to develop CAD/CAM application systems. The kernel contains geometric objects, such as points, curves and surfaces and a minimal set of functions for each type but does not contain lots of modeling and handling functions that are useful to create and maintain complex shapes from an idea sketch. The kernel was developed on MS-Windows NT using C++ with STL(Standard Template Library) but it is compatible with UNIX environments. This paper describes the structure of the kernel including several components: base, math, point sequence curve, geometry, translators. The base kernel gives portability to applications and the math kernel contains basic arithmetic and their classes, such as vector and matrix. The geometry kernel contains points, parametric curves, and parametric surfaces. A neutral fie format and programming and document styles are also presented in this paper.

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Boolean Factorization (부울 분해식 산출 방법)

  • Kwon, Oh-Hyeong
    • Journal of the Korean Society of Industry Convergence
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    • v.3 no.1
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    • pp.17-27
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    • 2000
  • A factorization is an extremely important part of multi-level logic synthesis. The number of literals in a factored form is a good estimate of the complexity of a logic function. and can be translated directly into the number of transistors required for implementation. Factored forms are described as either algebraic or Boolean, according to the trade-off between run-time and optimization. A Boolean factored form contains fewer number of literals than an algebraic factored form. In this paper, we present a new method for a Boolean factorization. The key idea is to build an extended co-kernel cube matrix using co-kernel/kernel pairs and kernel/kernel pairs together. The extended co-kernel cube matrix makes it possible to yield a Boolean factored form. We also propose a heuristic method for covering of the extended co-kernel cube matrix. Experimental results on various benchmark circuits show the improvements in literal counts over the algebraic factorization based on Brayton's co-kernel cube matrix.

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CONFORMAL MAPPING AND CLASSICAL KERNEL FUNCTIONS

  • CHUNG, YOUNG-BOK
    • Honam Mathematical Journal
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    • v.27 no.2
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    • pp.195-203
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    • 2005
  • We show that the exact Bergman kernel function associated to a $C^{\infty}$ bounded domain in the plane relates the derivatives of the Ahlfors map in an explicit way. And we find several formulas relating the exact Bergman kernel to classical kernel functions in potential theory.

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Separation of Kernel Space and User Space in Zephyr Kernel (Zephyr 커널에서 커널 공간과 사용자 공간의 분리 구현)

  • Kim, Eunyoung;Shin, Dongha
    • IEMEK Journal of Embedded Systems and Applications
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    • v.13 no.4
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    • pp.187-194
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    • 2018
  • The operating system for IoT should have a small memory footprint and provide low power state, real-time, multitasking, various network protocols, and security. Although the Zephyr kernel, an operating system for IoT, released by the Linux Foundation in February 2016, has these features but errors generated by the user code can generate fatal problems in the system because the Zephyr kernel adopts a single-space method that both the user code and kernel code execute in the same space. In this research, we propose a space separation method, which separates kernel space and user space, to solve this problem. The space separation that we propose consists of three modifications in Zephyr kernel. The first is the code separation that kernel code and user code execute in each space while using different stacks. The second is the kernel space protection that generates an exception by using the MPU (Memory Protection Unit) when the user code accesses the kernel space. The third is the SVC based system call that executes the system call using the SVC instruction that generates the exception. In this research, we implemented the space separation in Zephyr v1.8.0 and evaluated safety through abnormal execution of the user code. As the result, the kernel was not crashed by the errors generated by the user code and was normally executed.