• Journal of Information Processing Systems
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• 제8권3호
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• pp.409-420
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• 2012

The decision-making by agents in games is commonly based on reinforcement learning. To improve the quality of agents, it is necessary to solve the problems of the time and state space that are required for learning. Such problems can be solved by Macro-Actions, which are defined and executed by a sequence of primitive actions. In this line of research, the learning time is reduced by cutting down the number of policy decisions by agents. Macro-Actions were originally defined as combinations of the same primitive actions. Based on studies that showed the generation of Macro-Actions by learning, Macro-Actions are now thought to consist of diverse kinds of primitive actions. However an enormous amount of learning time and state space are required to generate Macro-Actions. To resolve these issues, we can apply insights from studies on the learning of tasks through Programming by Demonstration (PbD) to generate Macro-Actions that reduce the learning time and state space. In this paper, we propose a method to define and execute Macro-Actions. Macro-Actions are learned from a human subject via PbD and a policy is learned by reinforcement learning. In an experiment, the proposed method was applied to a car simulation to verify the scalability of the proposed method. Data was collected from the driving control of a human subject, and then the Macro-Actions that are required for running a car were generated. Furthermore, the policy that is necessary for driving on a track was learned. The acquisition of Macro-Actions by PbD reduced the driving time by about 16% compared to the case in which Macro-Actions were directly defined by a human subject. In addition, the learning time was also reduced by a faster convergence of the optimum policies.

• 한국농림기상학회지
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• 제4권3호
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• pp.133-140
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• 2002

Site-specific minimum temperature forecasts are critical in a short-term decision making procedure for preventive measures as well as a long-term strategy such as site selection in fruits industry. Nocturnal cold air pools frequently termed in mountainous areas under anticyclonic systems are very dangerous to the flowering buds in spring over Korea, but the spatial resolution to detect them exceeds the current weather forecast scale. To supplement the insufficient spatial resolution of official forecasts, we developed a GIS - assisted frost risk assesment scheme for using in mountainous areas. Daily minimum temperature data were obtained from 6 sites located in a 2.1 by 2.1 km area with complex topography near the southern edge of Sobaek mountains during radiative cooling nights in spring 2001. A digital elevation model with a 10 m spatial resolution was prepared for the entire study area and the cold air inflow was simulated for each grid cell by counting the number of surrounding cells coming into the processing cell. Primitive temperature surfaces were prepared for the corresponding dates by interpolating the Korea Meteorological Administration's automated observational data with the lapse rate correction. The cell temperature values corresponding to the 6 observation sites were extracted from the primitive temperature surface, and subtracted from the observed values to obtain the estimation error. The errors were regressed to the flow accumulation at the corresponding cells, delineating a statistically significant relationship. When we applied this relationship to the primitive temperature surfaces of frost nights during April 2002, there was a good agreement with the observations, showing a feasibility of site-specific frost warning system development in mountainous areas.

• 한국정밀공학회지
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• 제11권4호
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• pp.77-87
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• 1994

This paper deals with an automated forming sequence design system by which designers can determine desirable operation sequences even if they have little experience in the design of cold forging process. The forming sequence design in the cold forging is very important and requires many kinds of technical and empirical knowledge. They system isproposed, which generates forming sequence plans for the multistage cold forging of axisymmtrical solid products. Since the process of metal forming can be considered as a transformation of geometry, treatment of the geometry of the product is a key in planning process. To recognize the geometry of the product section, section entity representation and primitive geometries were used. Section entity representation can be used for the calculation of maximum diameter, maximum height, and volume. Forming sequence for the part can be determined by means of primitive geometries such as cylinder, cone, convex, and concave. By utilizing this geometrical characteristics (diameter, height, and radius), the product geometry is expressed by a list of the priitive geometries. Accordingly the forming sequence design is formulated as the search problem which starts with a billet geometry and finishes with a given product one. Using the developed system, the sequence drawing with all dimensions, which includes the proper sequence of operations for the part, is generated under the environment of AutoCAD. Based on the results of forming sequence, process variables(strain, punch pressure, die inner pressure, and forming load) are determined.

• 한국전자통신학회논문지
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• 제16권3호
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• pp.533-540
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• 2021

시스템의 성능을 평가하기 위하여 1차원 3-이웃 셀룰라 오토마타(Cellular Automata, 이하 CA) 기반의 의사 난수 생성기가 여러 분야에서 많이 응용되고 있다. 보다 더 효과적인 키 수열 생성을 위해 2차원 CA와 1차원 5-이웃 CA가 응용되었으나, 주어진 특성 다항식에 대응하는 대칭 1차원 5-이웃 CA를 설계하는 것은 매우 어려운 문제이다. 이를 해결하기 위해 특성 다항식의 점화식을 이용한 합성 방법, Krylov 행렬을 이용한 합성 방법과 같이 1차원 5-이웃 CA 합성에 관한 연구들이 진행되었다. 그러나 여전히 비선형 방정식을 풀어야 하는 문제점이 있었다. 이러한 문제점을 해결하기 위해, 최근 90/150 CA의 전이 행렬과 블록행렬을 이용한 1차원 5-이웃 CA 합성 방법이 제안되었다. 본 논문에서는 제안된 알고리즘의 이론적인 과정을 상세히 기술하고 그 알고리즘을 이용하여 높은 차수의 원시 다항식에 대응하는 대칭 1차원 5-이웃 CA를 구한다.

• 정보보호학회논문지
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• 제14권3호
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• pp.41-48
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• 2004

유한체의 곱셈과 나눗셈은 오류정정부호와 암호시스템에서 중요한 산술 연산이다. 유한체 GF(2$^{m}$ )의 원소를 표현하기 위해 다양한 기저가 사용되며 차수가 m인 GF(2)상의 원시다항식으로 구성할 수 있다. 정규기저를 사용하면 곱셈이나 곱셈 역원의 연산을 쉽게 수행할 수 있다. 정규기저 표현을 이용하는 Massey-Omura 승산기는 동일한 2진함수를 사용하여 몇 번의 순회치환으로 곱셈 또는 나눗셈이 수행되며 논리함수의 곱셈항 수가 승산기의 복잡도를 결정한다. 유한체의 정규기저는 항상 존재한다. 그러나 주어진 원시다항식에 대해 최적의 정규원소를 구하는 것은 쉽지 않다. 본 논문에서는 정규기저의 생성 방법을 고찰하고, Massey-Omura 승산기를 이용한 곱셈 또는 곱셈 역원의 계산에서 연산의 복잡도를 최소화할 수 있는 정규기저를 각 원시다항식에 대해 구하여, 최적의 정규원소와 곱셈항의 개수를 제시한다.

• Korean Chemical Engineering Research
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• 제48권4호
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• pp.519-533
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• 2010

본 연구에서는 L-형 아미노산인 L-Alanine과 무기염인 NaCl, KCl, $NaNO_3$ 및 $KNO_3$의 각 전해질로 이루어진 L-Alanine/전해질 수용액 계에서 L-Alanine의 활동도계수와 용해도를 298.15 K에서 측정하였다. L-Alanine의 활동도계수는 양이온 및 음이온의 선택성 전극으로 이루어진 화학전지에서 두 전극간의 기전력을 측정하는 전기화학 법으로 측정하였으며, 용해도는 L-Alanine의 고체상과 상평형을 이루고 있는 포화용액을 중량 분석하여 측정하였다. 한편 본 연구에서는 아미노산(L-Alanine)/전해질 수용액 계의 잔류(residual) Helmholtz 자유에너지를 섭동사슬-통계역학적 회합성유체이론(perturbed chain-statistical associating fluid theory)과 단순-평균구근사(primitive-mean spherical approximation)이론을 결합한 관계로 모델링 하였으며, 이로부터 아미노산의 활동도계수 및 용해도에 대한 열역학적 관계식을 얻었다. Helmholtz 자유에너지를 모델링 하는 과정에서는 아미노산은 양쪽성 이온(zwitterion) 형태로 존재하며 아미노산의 양쪽성 이온은 같은 이온끼리 자기-회합(self-association)하며 동시에 물분자와 교차-회합(cross-association)하는 회합체로 가정하였으며, 또한 아미노산의 양쪽성 이온이 전해질(무기염)로부터 해리된 양이온 및 음이온과 상호작용하여 이온복합체(ion complex)를 형성하는 과정을 회합현상으로 가정하였다. 본 연구에서 제안된 이론적 모델로부터 L-Alanine/전해질 수용액 계에서 계산되는 L-Alanine의 활동도계수 및 용해도 값은 본 연구의 실험값과 일치하는 경향을 보였다.

• Journal of Chest Surgery
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• 제26권9호
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• pp.726-729
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• 1993

Synovial sarcoma is a malignant soft tissue tumor originated from primitive mesenchymal cell. It occurs primarily in the paraarticular regions, parapharyngeal regions and abdominal wall. We experienced a case of intrapulmonary synovial sarcoma which was the first case originated from the lung and confirmed postoperatively.

• 대한수학회논문집
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• 제10권3호
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• pp.583-602
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• 1995

With the theory of a certain type of orders in a Quaternion algebra, we construct Brandt matrices and theta series. As a application, we calculate the class number of a certain type of orders in a Quanternion algebra with the trace formular of Brandt matrices.

• 대한수학회보
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• 제37권3호
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• pp.519-536
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• 2000

We construct a stationary, properly ordered Bratteli diagram B=(V,E,$\geq$) so that its Vershik map is isomorphic to Chacon's homeomorphism. It is the simplest stationary, properly ordered Bratteli diagram isomorphic to (Xc, Tc). We also find a primitive and proper substitution of Chacon's transformation.

• 대한수학회논문집
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• 제27권3호
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• pp.449-454
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• 2012

In this paper, we find the minimal polynomial of a primitive root of unity over cyclotomic fields. From this, we factorize cyclotomic polynomials over cyclotomic fields and investigate the coefficients of ${\Phi}_{3n}(x)$ when 3∤$n$.