• Journal of the Korean Geographical Society
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• v.47 no.6
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• pp.934-954
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• 2012

Constructed-response items are useful to estimate a higher-order thinking abilities such as sense of place, graphicacy, and geographical imaginations which are aimed by geography education. This study aims to identify the conception of the constructed-response items, to classify those feasible items in geography education, and to propose some comments and suggestions for development and application in Korea. The author tries to classify the constructed-response items by analyzing the NAEP items in the formal aspect and the aspect of cognitive dimension respectively. In the formal aspect, they are classified as 'question-standalone' type and 'material-presenting' type. In the aspect of cognitive dimension, they are classified into three types as 'knowledge-requirement', 'understanding-requirement', and 'applying-requirement'. Some comments and suggestions are as follows. First, it is necessary to develope the constructed-response items that coherent to both content and cognitive dimensions. Second, it is required for students who take an examination to use a great variety of graphics, photos, thematic maps related to geography. Third, we need to inquire the rubric, grade, process to scoring because they are vital to success of the constructed-response items.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.4
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• pp.85-90
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• 2018

This paper compares the adaptive eualization performance of CR-MMA (Constellation Reduction-MMA) and CR-MMA (Constellation Matching-MMA) in order to minimization of intersymbol interference that is occur in channel for 2-dimensional QAM signal. For obtain the error signal in order to updating the tap coefficient of conventional adaptive equalization algorithm MMA, the CR-MMA converts the constellation reduction concept of high order 2-dimensional QAM nonconstant modulus signal to constant modulus signal and the CM-MMA use the constellation matchine error concept in order to force the matching the $2^{nd}$ and $4^{th}$ cumulant of equalizer output and transmitted signal constellation. By applying the different method for getting the error signal, these algorithm are possible to obtain the improved equalization performance compared to the conventional MMA algorithm, the improved performance of CR-MMA and CM-MMA were compared by computer simulation in this paper. As a result of simulation, the CM-MMA has more better performance in the equalizer internal performance than CR-MMA, but not in equalizer external performance as in SER.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.5 no.1
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• pp.3-16
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• 1995

In this paper, we deal with the cryptographic properties of Boolean functions generated by recursively extended methods from the points of balancedness, nonlinearity and correlation properties. First, we propose a new concept 'Strict Uncorrelated Criterion(SUC)' for two Boolean functions as a necessary condition for constructing Boolean functions of S-box which can be guaranteed to be resistant against Differential cryptanalysis, then we show that the recurively extended Boolean functions with particular form preserve the SUC. We also examine the correlation properties of Boolean functions using Walsh-Hadamard transformations and apply them to discuss nonlinearity, correlation properties and SUC of semi-bent function which is defined over odd dimensional vector space. Finally, we compare semi-bent function with Boolean functions which are generated by other similar recursive methods.

• 한국전산유체공학회:학술대회논문집
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• 1995.10a
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• pp.197-202
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• 1995

비정상(unsteady) 압축성(compressible) 유동에 의한 공력음향(aeroacoustics)을 모사하여 공력소음원을 해석하기 위해서는 고차(high order)의 정확도와 높은 해상도(resolution)를 가지며, 상대적으로 계산시간을 많이 필요로 하지 않는 외재적(explicit) 유한차분법이 필수적으로 요구된다. 이것은 주어진 차분방식과 격자계로써 공간과 시간상에 존재하는 미소크기의 파동성분들을 충분히 구현하여야 만족할 만한 수치해를 얻을 수 있기 때문이다. 본 연구에서는, 그러한 유한차분법 중 최근에 관심의 대상이 되고있는 삼각(tridiagonal)또는 오각(pentadiagonal) 집적유한차분법(compact finite difference scheme)이 최대의 해상도를 갖도록 하는 수학적인 방법을 개발하고, 이 방법으로써 새롭게 집적유한차분법을 최적화하였다. 개발된 최적화 방법은, 푸리에 해석법(Fourier analysis)을 통하여 파동수(wavenumber) 영역에서 수학적으로 계산된 위상오차(phase error)를 최소화하는 것이며, 이러한 개념과 방법은 본 연구에서 처음으로 집적유한차분법에 적용되었다. 여러가지 절단정확도(truncation order)에 대해서 최적화 된 집적유한차분법들이 실제 공간과 시간상에서 보여주는 정확도와 오차특성을 알아보기 위하여, 이 방법들을 1차원 선형파동방정식에 적용하였고, 이 결과를 통하여 가장 정확하고 효과적인 절단정확도의 집적유한차분법을 선별하였다. 특히, 오각(pentadiagonal)법에 비해 더욱 효율적인 6차 삼각(tridiagonal)법을 1차원 Euler방정식에 적용하여, 비선형 파동에 대한 모사를 수행할 수 있었다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.2
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• pp.19-25
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• 2003

For a class of multi-input multi-output nonlinear systems which perform a given task repetitively, an extended type of a direct leaning control (DLC) is proposed using the information on the (vector) relative degree of a multi-input multi-output system. Existing DLC methods are observed to be applied to a limited class of systems with the relative degree one and a new DLC law is suggested which can be applied to systems having higher relative degree. Using the proposed control law, the control input corresponding to the new desired output trajectory is synthesized directly based on the control inputs obtained from the learning process for other output trajectories. To show the validity and the performance of the proposed DLC, simulations are performed for trajectory tracking control of a two-axis SCARA robot.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.4
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• pp.313-320
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• 1991

The paper describes the formulation for the analysis of the flexural free vibration of rectangular plate structure by the transfer influence coefficient method, which was developed on the base of the concept of the successive transmission of dynamic influence coefficients. For the analysis of rectangular plate which two opposite sides are simply-supported edge condition, the results of simple numerical examples demonstrate the validity of the present method, that is, the numerical high accuracy, the high speed and the flexibility for programming, compared with results of the transfer matrix method and exact solution or Leissa's method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.3
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• pp.106-114
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• 2006

This study proposed the applicability of inverse stiffness method on the seismic design for steel frame with buckling restrained braces and the design results were compared with former research's. The concept of this method is simple and efficient. Furthermore it is able to reflect the high mode's effect and control the ductility factors of each story individually. Design results using the proposed method showed that according to increase of the given target drift, the areas of brace generally decreased but partially increased in some stories of the tall structure with very large ductility. And the post yield stiffness ratio's variation had more effect on the design results in the small post yield stiffness ratio.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.675-678
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• 2013

암호 알고리즘이 탑재된 환경에서 암호 알고리즘의 이론적 안전성이 고려되어도 환경에 의존한 부가적 정보를 활용하는 부채널 분석에 대한 안전성이 검토되어야 한다. 최근까지 부채널 분석에 대한 안전성을 고려한 대응기법으로 마스킹 기법이 적용되었으나, 이와는 상반된 개념인 하드웨어 DPL(Dual-rail with Precharge Logic) 기법을 응용한 균일한 해밍웨이트를 제공하는 소프트웨어 AES(Advanced Encryption Standard)가 제안되었다. 최근, 소프트웨어 기반 블록암호에 대해 고차 마스킹 부채널 대응법의 비효율성으로 새로운 방법에 대한 다양한 시도가 되고 있으며, 그 중 균일한 해밍웨이트를 제공하는 표현 방법이 효율적이고 안전한 새로운 대응법으로 검토되어지고 있다. 하지만, 논문에서는 균일한 해밍웨이트 데이터 표현방법 기반 부채널 대응법을 해독하는 차분전력분석 방법을 소개한다. 실험을 통해, AES 128비트 키 중 일부분이 분석됨을 확인하였다. 이는 공격자가 테이블 변환 정보를 활용할 수 있다는 다소 강력한 가정하에 실험하였기 때문이다. 앞선 가정 하에 안전성을 제공하기 위해서는 차후 추가적 대응기법이 고려되어야 한다.

• Journal of the Korean Chemical Society
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• v.57 no.5
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• pp.640-655
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• 2013

The purpose of this study is to analyze the cognitive demands level of the description about 'changes of state' and 'kinetic theory' on the 'science 1' textbooks by the 2007 revised curriculum. The three types of curriculum analysis taxonomy have been used to analyze the cognitive demands level of those contents on the 6 kinds of 'science 1' textbooks. The most higher level of cognitive demands about the concepts have been discussed here due to the focus of the concepts. The first, the cognitive demand level about 'three states of substances' depending on the motion of their particles in 6 textbooks is a early formal operational stage because of using by the application of kinetic theory. The second, the cognitive demand level about 'diffusion' and 'evaporation' is a early formal operational stage, because the particles move around faster so they can change their position. The third, the cognitive level of the pressure and volume in a gas is a early formal operational stage because of explaining only phenomena in simple correspondence with formal model of kinetic theory. And simple functional relationships beyond linear on the graph of the volume and pressure of gas, the volume and temperature of gas is also a early formal operational stage. The fourth, the cognitive level of the energy of heat by a change of the state is also a early formal operational stage because kinetic theory picture accepted as providing explanation by the change of the state. And functional relationships beyond linear on the graph of the explanation of boiling point of water in water is also a early formal operational stage.

• Korean Journal of Cognitive Science
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• v.13 no.4
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• pp.80-80
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• 2002

The main thesis of this article is that the decisive point of creativity education is the cultivation of critical thinking capability. Although the narrow conception of creativity as divergent thinking is not subsumed under that of critical thinking, the role of divergent thinking is not so crucial in the science context of creative problem-solving. On the contrary, the broad conception of creativity as focusing on the reference to utility and the third conception of creativity as a process based on the variation and combination of existing pieces of information are crucial in creative problem-solving context, which are yet subsumed under that of critical thinking. The emphasis on critical thinking education is connected with the characteristics of contemporary knowledge-based society. This rapidly changing society requires situation-adaptive or situation-sensitive cognitive ability, whose core is critical thinking capability. Hence, the education of critical thinking is to be centered on the learning of blowing-how and procedural knowledge but not of knowing-that and declarative knowledge. Accordingly, the learning of critical thinking is to be headed towards the cultivation of competence but not just of performance. In conclusion, when a rational problem-solving through critical and logical thinking turns out consequently to be novel, we call it creative thinking. So, creativity is an emergent property based on critical and logical thinking.