• Journal of applied mathematics & informatics
• /
• 제2권2호
• /
• pp.21-46
• /
• 1995

Congestion and memory occupancy in computer system may be reduced further if new jobs are admitted only when the num-ber of jobs queued at CPU is below CPU run queue cutoff (RQ). In this paper we prove that response time of a job is invariant with respect to RQ if jobs do not communicate each other. We also demonstrate this invariance property numerically using marix-geometric methods and present an approximate method for the delay due to context switch-ing under time slicing. The approximation suggests that time slicing with constant overhead yields a throughput similar to an FCFS system without overhead.

• 대한수학회지
• /
• 제54권2호
• /
• pp.493-506
• /
• 2017

In this paper, we define the modulus of n-dimensional U-flatness as the determinant of an $(n+1){\times}(n+1)$ matrix. The properties of the modulus are investigated and the relationships between this modulus and other geometric parameters of Banach spaces are studied. Some results on fixed point theory for non-expansive mappings and normal structure in Banach spaces are obtained.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
• /
• pp.427-430
• /
• 1989

For on-line ARMA spectral estimation, the fast transversal filter algorithm of extended least squares method(ETS FTF) is presented. The projection operator, a key tool for geometric approach, is used in the derivation of the algorithm. ELS FTF is a fast time update recursion which is based on the fact that the correlation matrix of ARMA model satisfies the shift invariance property in each block, and thus it takes 10N+31 MADPR.

• Communications for Statistical Applications and Methods
• /
• 제11권2호
• /
• pp.213-225
• /
• 2004

A fixed-strike lookback option is an option whose payoff is determined by the maximum (or minimum) price of the underlying asset within the option's life. Under the Black-Scholes framework, the time-t price of an equity asset follows a geometric Brownian motion. Applying the method of Esscher transforms, this paper will derive explicit pricing formulas for fixed-strike lookback call and put options, respectively. In addition, this paper will show a relationship (duality property) between the pricing formulas of the call and put options. Finally, this paper will derive explicit pricing formulas for the fixed-strike lookback options when their underlying asset pays dividends continuously at a rate proportional to its price.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2009년도 제38회 동계학술대회 초록집
• /
• pp.404-404
• /
• 2010

Despite much works have been done on the geometric structures of ripples, defects and edge atoms in a graphene device, there has been no report showing the direct correlation between the structures and the transport property. Unlike scanning tunneling microscopy or other electron microscopes, Scanning Gate Microscope (SGM) is a unique microscopic tool with which the local electronic structure and the transport property of a device can be measured simultaneously. We have performed a transport measurement in nanometer scale using a scanning gate microscope (SGM). We have found the nanoscopic pictures of electron and hole puddles and the role of graphene- device edges in the transport measurements. These experimental findings were successfully explained with a theoretical model.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 1998년도 가을 학술발표회 논문집
• /
• pp.251-257
• /
• 1998

Spherical space frame structure with triangular network pattern, which has the various characteristics for the mechanic property, a funtional property, an aesthetic property and so on, has often been used as one of the most efficient space structures. It is expected that this type will be used widely in large-span structural roofs. But because this structure is made of network by combination of line elements there me many nodes therefore, the structure behavior is very complicated and there can be an overall collapse of structure by buckling phenomenon if the external force reaches a limitation. This kind of buckling is due to geometric shape, network pattern, the number of layer and so on, of structure. Therefore spherical space frame with triangle network pattern have attracted many designers and researchers attention all over the world. The number of layer of space frame is divided in to the simgle, double, multi layer. That is important element which is considered deeply in the beginning of structural design. The buckling characteristics of single-layer model and double-layer model for the spherical space frame structure with triangular network pattern are evaluated and the buckling loads of these types are compared with investigation their structural efficiency in this study.

• 제어로봇시스템학회논문지
• /
• 제22권9호
• /
• pp.710-715
• /
• 2016

Due to its simplicity and high reliability, the box-counting(BC) method is one of the most frequently used techniques to estimate the fractal dimensions of a binary image with a self-similarity property. The fractal calculation requires data sampling that determines the size of boxes to be sampled from the given image and directly affects the accuracy of the fractal dimension estimation. There are three non-overlapping regular grid methods: geometric-step method, arithmetic-step method and divisor-step method. These methods have some drawbacks when the image size M becomes large. This paper presents a BC algorithm for enhancing the accuracy of the fractal dimension estimation based on a new sampling method. Instead of using the geometric-step method, the new sampling method, called the coverage ratio-step method, selects the number of steps according to the coverage ratio. A set of experiments using well-known fractal images showed that the proposed method outperforms the existing BC method and the triangular BC method.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 추계학술대회 논문집
• /
• pp.687-690
• /
• 2000

Lately, many studies have been progressed for the protection human's lives and property as holding in check accidents happened by human's carelessness or mistakes. One part of these is the development of an autonomouse vehicle. General control method of vision-based autonomous vehicle system is to determine the navigation direction by analyzing lane images from a camera, and to navigate using proper control algorithm. In this paper, characteristic points are abstracted from lane images using lane recognition algorithm with sobel operator. And then the vehicle is controlled using two proposed auto-steering algorithms. Two steering control algorithms are introduced in this paper. First method is to use the geometric relation of a camera. After transforming from an image coordinate to a vehicle coordinate, a steering angle is calculated using Ackermann angle. Second one is using a neural network algorithm. It doesn't need to use the geometric relation of a camera and is easy to apply a steering algorithm. In addition, It is a nearest algorithm for the driving style of human driver. Proposed controller is a multilayer neural network using Levenberg-Marquardt backpropagation learning algorithm which was estimated much better than other methods, i.e. Conjugate Gradient or Gradient Decent ones.

• 천문학회보
• /
• 제37권2호
• /
• pp.106.1-106.1
• /
• 2012

The Gegenschein is a faint glow around the anti-solar point caused by the interplanetary dust particle(IDP)'s back-scattering enhancement. From the previous low resolution observations, the overall morphology of the Gegenschein has been intensively studied. However, sub-degree scale fine structure of the Gegenschein is still not well known, even though the detailed morphology of the Gegenschein within a few degree from the anti-solar point may supply pivotal information about the property of the IDPs. We made optical CCD observations of the Gegenschein between 2003 March and 2006 November. From the observations, we succeeded in making high resolution images of the Gegenschein, with unprecedented 1.'4 resolution. Our results concur with IDP cloud model based on the infrared observations combined with scattering phase function derived from low resolution data. The only exception is the anti-solar point. We found a steep additional brightness enhancement existing at the exact anti-solar point. Plausible explanation of the finding is that the IDPs are significantly larger than observing wavelength, and have irregular morphology or inhomogeneous internal structure. Furthermore, we measured average geometric albedo of the IDPs from the optical brightness of the anti-solar point. The geometric albedo was $0.06{\pm}0.01$, similar to those of comets or C-type asteroids.

• 지질공학
• /
• 제1권1호
• /
• pp.137-145
• /
• 1991

열극암반에서의 유동특성은 석유산업, 지열수탐사, 지하수의 오염문제, 지하 동굴건설 등 많은 공학적 분야에서 선결되어야 하는 중요성을 갖고 있다. 암반을 통한 지하수의 유동은 연속체 개념과 불연속열극 개념에 의하여 수치모형화 되고 또한 해석되고 있다. 불연속 열극체계 개념은 국지적인 각 열극의 특성을 강조하는 반면, 다공성매질 개념은 수리학적 파라메타의 평균값을 쓰기 때문에 각 열극의 특성은 무시하게 된다. 지하동굴에서 관찰된 지하수 유입특성에 의하면, 지하수는 channel 형태로 유동한다고 해석되어지고 있다. 이러한 channel 현상은 복합적인 열극의 기하학적 특성에 따른 열극틈의 변화에 의하여 이루어 진다.