• 대한수학교육학회지:수학교육학연구
• /
• 제21권3호
• /
• pp.239-259
• /
• 2011

본 연구는 초등학생들의 일반화된 산술로서의 대수적 추론 능력의 실태를 알아보고자, 연산의 성질 이해 과제로 구성된 검사 도구를 이용하여 2학년 648명, 4학년 688명, 6학년 751명의 반응을 분석하였다. 분석 결과, 상당수의 학생들이 문제 상황에 포함된 연산의 성질을 제대로 파악하지 못하였고, 연산의 성질을 적용하여 문제를 해결하는 데 많은 어려움을 겪는 것으로 드러났다. 연산의 성질별로는 교환법칙 과제에서는 저학년에서부터 높은 성공률을 보인 반면, 결합법칙과 분배법칙에서는 고학년에서도 매우 낮은 성공률을 보였다. 문제 상황별로는 특히, 결합법칙 및 분배법칙 과제의 경우 구체적인 수 상황에서의 성공률이 임의의 수 상황에서의 성공률에 비해 상대적으로 더 낮게 나타났다. 이러한 결과들을 토대로 본 논문은 초등학교에서의 대수 지도 방안에 대한 시사점을 제공하였다.

• Journal of Biosystems Engineering
• /
• 제23권2호
• /
• pp.105-114
• /
• 1998

Granule application with a boom has merits of accurate application and high field efficiency. In order to develop a boom granule applicator, aerodynamic properties of agrichemicals should be investigated. This study was accomplished to investigate aerodynamic properties of granules and factors affecting on them. The tested agrichemicals were urea, compound fertilizer (17-21-17), sand and zeolite. Basic physical properties of granules such as true density, sphericity, and arithmetic mean diameter for those materials were analyzed. Regression equations for pickup velocity (v$_{p}$) and saltation velocity (v$_{s}$) were proposed by the data transformation and the multi-regression analysis as follows : (equation omitted) where, 0< s < 1, 0< λ$_{i}$< 3, 35 < D/d$_{p}$ < 350, 1000 $_{p}$/p$_{a}$ < 2500 The range of pickup velocity of fertilizers and other agrichemicals were shown to be 10-16m/s and 9-13m/s, respectively. The saltation velocity of fertilizer and other agrichemicals were 3 m/s and 4 m/s, respectively.y.ively.y.y.

• Geomechanics and Engineering
• /
• 제36권3호
• /
• pp.259-276
• /
• 2024

The undrained shear strength is widely acknowledged as a fundamental mechanical property of soil and is considered a critical engineering parameter. In recent years, researchers have employed various methodologies to evaluate the shear strength of soil under undrained conditions. These methods encompass both numerical analyses and empirical techniques, such as the cone penetration test (CPT), to gain insights into the properties and behavior of soil. However, several of these methods rely on correlation assumptions, which can lead to inconsistent accuracy and precision. The study involved the development of innovative methods using extreme gradient boosting (XGB) to predict the pile set-up component "A" based on two distinct data sets. The first data set includes average modified cone point bearing capacity (q_t), average wall friction (f_s), and effective vertical stress (σ_vo), while the second data set comprises plasticity index (PI), soil undrained shear cohesion (S_u), and the over consolidation ratio (OCR). These data sets were utilized to develop XGBoost-based methods for predicting the pile set-up component "A". To optimize the internal hyperparameters of the XGBoost model, four optimization algorithms were employed: Particle Swarm Optimization (PSO), Social Spider Optimization (SSO), Arithmetic Optimization Algorithm (AOA), and Sine Cosine Optimization Algorithm (SCOA). The results from the first data set indicate that the XGBoost model optimized using the Arithmetic Optimization Algorithm (XGB - AOA) achieved the highest accuracy, with R2 values of 0.9962 for the training part and 0.9807 for the testing part. The performance of the developed models was further evaluated using the RMSE, MAE, and VAF indices. The results revealed that the XGBoost model optimized using XGBoost - AOA outperformed other models in terms of accuracy, with RMSE, MAE, and VAF values of 0.0078, 0.0015, and 99.6189 for the training part and 0.0141, 0.0112, and 98.0394 for the testing part, respectively. These findings suggest that XGBoost - AOA is the most accurate model for predicting the pile set-up component.

• 한국수학사학회지
• /
• 제12권1호
• /
• pp.1-12
• /
• 1999

The first part of this thesis discusses the types and the properties of errors, one of which makes up systematic errors of measurements, removable by detecting their causes, the other errors of accidental causes which can not be removed. The final part of this thesis deals with the historical background of the Gaussian distribution by Hershel, Hagen, Laplace and Gauss from the late 18th century to the early 19th century. It can be concluded that the accidental idea and the treatment of accidental error distribution by Gauss Is the best one based on the assumption that the most probable value of true value is the arithmetic mean of data, obtained by repeated measurements of a given quantity.

• 대한수학회보
• /
• 제56권2호
• /
• pp.521-533
• /
• 2019

In this paper, we define a mean of two positive numbers called the k-golden mean and study some properties of it. Especially, we show that the 2-golden mean refines the harmonic and the geometric means. As an application, we define the k-golden ratio and give some properties of it as an generalization of the golden ratio. Furthermore, we define the matrix k-golden mean of two positive-definite matrices and give some properties of it. This is an improvement of Lim's results [2] for which the matrix golden mean.

• 대한수학회보
• /
• 제59권4호
• /
• pp.843-852
• /
• 2022

In this paper, we study some properties of Bézout and weakly Bézout rings. Then, we investigate the transfer of these notions to trivial ring extensions and amalgamated algebras along an ideal. Also, in the context of domains we show that the amalgamated is a Bézout ring if and only if it is a weakly Bézout ring. All along the paper, we put the new results to enrich the current literature with new families of examples of non-Bézout weakly Bézout rings.

• East Asian mathematical journal
• /
• 제35권1호
• /
• pp.9-15
• /
• 2019

Kaavya introduce an involution on the set of partitions with crank 0 and studied the number of partitions of n which are invariant under Kaavya's involution. If a partition ${\lambda}$ with crank 0 is invariant under her involution, we say ${\lambda}$ is a self-conjugate partition with crank 0. We prove that the number of such partitions of n is equal to the number of partitions with rank 0 which are invariant under the usual partition conjugation. We also study arithmetic properties of such partitions and their q-theoretic implication.

• Kyungpook Mathematical Journal
• /
• 제53권3호
• /
• pp.479-495
• /
• 2013

Taking the weighted geometric mean [11] on the cone of positive definite matrix, we propose an iterative mean algorithm involving weighted arithmetic and geometric means of $n$-positive definite matrices which is a weighted version of Carlson mean presented by Lee and Lim [13]. We show that each sequence of the weigthed Carlson iterative mean algorithm has a common limit and the common limit of satisfies weighted multidimensional versions of all properties like permutation symmetry, concavity, monotonicity, homogeneity, congruence invariancy, duality, mean inequalities.

• 대한전자공학회논문지
• /
• 제15권5호
• /
• pp.29-33
• /
• 1978

본 논문에서는 Galois 스윗칭함수를 구하기 위해서 임의의 유한체상에서 정의되는 Galois 체의 성질을 설명하였고, 임의의 유한체상에서의 연산방법을 밝혔다. 고리고 Lagrange 보간법에 의한 다항식이 유한체상에서 전개될 수 있음을 증명하였다 이 결과를 적용하여 단일변수를 갖는 Galois스윗칭 함수를 유도하고 다치논리회로를 실현하였다.

• 대한수학회논문집
• /
• 제23권4호
• /
• pp.479-485
• /
• 2008

In this note, we study arithmetic properties for the exponents of modular forms on ${\Gamma}_0(p)$ for primes p. Our aim is to refine the result of [4] by using the geometric property of the modular curve of ${\Gamma}_0(p)$.