• 정보학연구
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• 제6권3호
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• pp.65-73
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• 2003

본 논문에서는 IBM의 고성능 임베디드(embedded) 프로세서인 405GP와 Linux 2.4.21를 이용하여 5.2GHz 대역에서 최대 54Mbps의 대역폭을 제공할 수 있는 IEEE 802.11a 기반의 AP (Access point) 개발에 관하여 연구하였다. AP의 하드웨어는 PowerPC기반의 IBM 405GP 프로세서를 기반으로 설계하였고 AP 소프트웨어는 405GP을 위한 PowerPC 부트로더, open source인 최근 Linux 커널 2.4.21을 사용하여 구현하였다. 또한 시스템 패키징은 최신 Linux 커널이 지원하는 MTD 기술과 JFFS2 플래쉬 파일시스템을 이용하여 최적으로 구현하였다.

• 한국대기환경학회지
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• 제15권6호
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• pp.757-765
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• 1999

Lagrangian particle dispersion model(LPDM) is an effective tool to calculate the dispersion from a point source since it dose not induce numerical diffusion errors in solving the pollutant dispersion equation. Fictitious particles are released to the atmosphere from the emission source and they are then transported by the mean velocity and diffused by the turbulent eddy motion in the LPDM. The concentration distribution from the dispersed particles in the calculation domain are finally estimated by applying a particle count method or a Gaussian kernel method. The two methods for calculating concentration profiles were compared each other and tested against the analytic solution and the tracer experiment to find the strength and weakness of each method and to choose computationally time saving method for the LPDM. The calculated concentrations from the particle count method was heavily dependent on the number of the particles released at the emission source. It requires lots fo particle emission to reach the converged concentration field. And resulting concentrations were also dependent on the size of numerical grid. The concentration field by the Gaussian kernel method, however, converged with a low particle emission rate at the source and was in good agreement with the analytic solution and the tracer experiment. The results showed that Gaussian kernel method was more effective method to calculate the concentrations in the LPDM.

• 농업과학연구
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• 제50권4호
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• pp.645-652
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• 2023

The aleurone layer in maize is crucial as it contains essential nutrients such as minerals, vitamins, and high-quality proteins. While most of the maize varieties are known to possess a single aleurone layer, several multi-aleurone layer mutants and landraces have been suggested for hierarchical genetic control of aleurone development. Conventional microscopy analysis often involves using immature seeds or sampling only a portion of the kernel sample, and whole kernel section analysis using a microtome is technically difficult and time-consuming. Additionally, the larger size of maize kernels posed challenges for comprehensive cross-sectional analysis compared to other cereal crops. Consequently, this study aimed to develop an efficient method to comprehensively understand the aleurone layer characteristics of the entire cross-section in maize. Through observations of diverse maize genetic resources, we confirmed irregular aleurone layer patterns in those with multiple aleurone layers, and we discovered a landrace having multiple aleurone layers. By selectively identifying genetic resources with multiple aleurone layers, this method may contribute to efficient breeding processes in maize.

• 대한원격탐사학회지
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• 제5권1호
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• pp.41-56
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• 1989

Improvement of the multichannel sea surface temperature(MCSST) software, which had been developed for the purpose of operating under mainframe computer system, was seeked in order to operate effectively in a mini computer system. CPU time and processing time, which is not a major factor under mainframe computer system, become a critical factor in real time image processing under mini computer system. Due to fixed kernel size(3$\times$4) of the old MCSST software, high spatial resolution characteristics of the original image received from satellites were apparently degraded when images are transformed into a cartesian coordinate system after geometrical distortions of the image due to earth curvature are removed. CPU and processing time were reduced to 0.13 and 0.15~0.22 comparing with the old MCSST's, respectively, by applying disk block I/O and M/T queue I/O method under VAX-11/750 computer. The high resolution quality (1.1km in AVHRR) of the processed image was guaranted using 2$\times$2 kernel size and applying moving window techniques without sacrificing CPU and processing time much.

• 정보보호학회논문지
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• 제25권4호
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• pp.863-872
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• 2015

커널 루트킷은 운영체제의 컴포넌트 사이의 통신을 가로채거나 수정할 수 있기 때문에, 운영 체제의 무결성을 훼손시킬 수 있는 가장 위협적이고 널리 퍼진 위협 중 하나로 인식되고 있다. 커널 루트킷이 이미 커널 권한을 획득하였기 때문에 루트킷이 설치된 공간에서 커널을 보호하는 것은 안전하지 않다. 따라서 커널보호 시스템은 커널과 동일한 공간으로부터 독립적이어야만 한다. 루트킷을 탐지하기 위해 많은 연구들이 수행되어 왔지만 다른 연구들과 달리 TrustZone 기반 연구는 커널과 동일한 공간으로부터 분리되고, 독립된 공간에서 커널을 보호하는 것이 가능하다. 하지만 제안된 방법들은 커널보호 시스템을 완전히 독립시킬 수 없는 단점이 있다. 이러한 이유로, 우리는 TrustZone의 시큐어 타이머를 이용한 효율적인 커널 검사 시스템을 제안한다. 이 시스템은 레퍼런스의 무결성을 보장하기 위해 커널 원본 이미지인 vmlinux을 활용하여 측정하였다. 또한, 보호영역 크기에 대한 유연성을 제공함으로써 효율적으로 커널보호 시스템을 운영하는 것이 가능하다. 실험 결과들은 제안된 커널보호 시스템이 완전히 독립되어 운영되고, 런타임동안 최대 6%정도의 성능만 저하시킨다는 것을 보여준다.

• Communications for Statistical Applications and Methods
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• 제15권5호
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• pp.709-717
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• 2008

The difference of two one-sided kernel estimators is usually used to detect the location of the discontinuity points of regression function. The large absolute value of the statistic imply discontinuity of regression function, so we may use the difference of two one-sided kernel estimators as the test statistic for testing null hypothesis of a smooth regression function. The problem is, however, we only know the asymptotic distribution of the test statistic under $H_0$ and we hardly expect the good performance of test if we rely solely on the asymptotic distribution for determining the critical points. In this paper, we show that if we adjust the bias of test statistic properly, the asymptotic rules hold for even small sample size situation.

• Communications for Statistical Applications and Methods
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• 제26권6호
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• pp.611-622
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• 2019

This paper considers the estimation of the long memory parameter in nonparametric regression with strongly correlated errors. The key idea is to minimize a unified mean squared error of long memory parameter to select both kernel bandwidth and the number of frequencies used in exact local Whittle estimation. A unified mean squared error framework is more natural because it provides both goodness of fit and measure of strong dependence. The block bootstrap is applied to evaluate the mean squared error. Finite sample performance using Monte Carlo simulations shows the closest performance to the oracle. The proposed method outperforms existing methods especially when dependency and sample size increase. The proposed method is also illustreated to the volatility of exchange rate between Korean Won for US dollar.

• 한국대기환경학회지
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• 제14권4호
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• pp.303-312
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• 1998

To obtain the solution to the time-dependent particle size distribution of an aerosol undergoing gravitational coagulation, the moment method was used which converts the non linear integro-differential equation to a set of ordinary differential equations. A semi-numerical solution was obtained using this method. Subsequently, an analytic solution was given by approximating the collision kernel into a form suitable for the analysis. The results show that during gravitational coagulation, the geometric standard deviation increases and the geometric mean radius decreases as time increases.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2006년도 한국약용작물학회 공동춘계학술발표회
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• pp.384-385
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• 2006

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권7호
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• pp.2496-2511
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• 2014

Face recognition is considered a complex biometrics in the field of image processing mainly due to the constraints imposed by variation in the appearance of facial images. These variations in appearance are affected by differences in expressions and/or occlusions (sunglasses, scarf etc.). This paper discusses incremental Kernel Fisher Discriminate Analysis on sub-classes for dealing with partial occlusions and variant expressions. This framework focuses on the division of classes into fixed size sub-classes for effective feature extraction. For this purpose, it modifies the traditional Linear Discriminant Analysis into incremental approach in the kernel space. Experiments are performed on AR, ORL, Yale B and MIT-CBCL face databases. The results show a significant improvement in face recognition.