• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.29 no.2 s.233
• /
• pp.232-238
• /
• 2005

The 'Mixing Index($D_I$)' is used as a conventional guidance measuring the degree of mixing for multiphase flows. For the case when insoluble solutions flow in a passive micromixer, a new method to calculate $D_I$ is proposed. The 'Vortex Index(${\Omega}_I$)' is suggested and formulated. We infer that ${\Omega}_I$ relates to the degree of chaotic advection. Various arbitrary shaped microchannels were tested to calculate the $D_I\;and\;{\Omega}_I$, and then a simple algebraic equation, $D_I=Aexp(B{\Omega}_I)$, is obtained. This equation may be used instead of the conventional partial differential equation, concentration equation, to estimate the degree of mixing.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.1841-1844
• /
• 2004

'Mixing Index($D_I$)'s generally used to measure the degree of mixing. A new method to calculate $D_I$ was proposed, when insoluble solution flows in micromixer. 'Vortex Index (${\Omega}_I$)'which indicate the degree of chaotic advection, is defined and formulated. A lots of arbitrary shaped microchannels were tested to calculate the $D_I$ and ${\Omega}_I$. And then a simple algebraic equation, $D_I=A{\Omega}_I+B$, was obtained. This equation may be used instead of partial differential equation, concentration equation.

• Bulletin of the Korean Mathematical Society
• /
• v.50 no.6
• /
• pp.2001-2011
• /
• 2013

Cho and Kim [4] have introduced the concept of the competition index of a digraph. Similarly, the competition index of an $n{\times}n$ Boolean matrix A is the smallest positive integer q such that $A^{q+i}(A^T)^{q+i}=A^{q+r+i}(A^T)^{q+r+i}$ for some positive integer r and every nonnegative integer i, where $A^T$ denotes the transpose of A. In this paper, we study the upper bound of the competition index of a Boolean matrix. Using the concept of Boolean rank, we determine the upper bound of the competition index of a nearly reducible Boolean matrix.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2000.11a
• /
• pp.49-54
• /
• 2000

Several soil parameters can be calculated for results of Piezocone test; sensitivity, soil classification, OCR, undrained shear strength, coefficient of consolidation etc., and used to analysis geotechnical problems. Particularly, the coefficient of consolidation which is related to degree of consolidation varies according to rigidity index(I/sub r/). In this study, rigidity index(I/sub r/) was analyzed by Roy's formula. Trixial tests and unconfined compression tests data in the ten sites was analyzed. In conclusion, rigidity index(I/sub r/) was suggested such as rigidity index(I/sub r/) = 15∼60, average rigidity index value(I/sub r/) of approximately 33 within a country.

• Journal of applied mathematics & informatics
• /
• v.36 no.3_4
• /
• pp.307-315
• /
• 2018

Let G be a simple connected graph with n vertices and m edges, with a sequence of vertex degrees $d_1{\geq}d_2{\geq}{\cdots}{\geq}d_n$ > 0. A vertex-degree topological index, referred to as harmonic index, is defined as $H={\sum{_{i{\sim}j}}{\frac{2}{d_i+d_j}}$, where i ~ j denotes the adjacency of vertices i and j. Lower and upper bounds of the index H are obtained.

• Proceedings of the KSR Conference
• /
• 2007.11a
• /
• pp.1657-1667
• /
• 2007

This study propose a model for railway safety evaluation with which the safety of whole railway system can be evaluated. The evaluation model is to generate a safety index which quantitatively represent the degree of railway safety. Safety index is proposed a function of three indexes; an accident index, safety management index, and safety culture index. This paper describes the first result from the study on the safety target which will be a key starting point toward the development of safety evaluation model. It is recommended that the safety target be composed of several sub-targets that are apportioned to constituent components. It is concluded that the classification of safety target influence on deciding components or attributes that constitute each sub-indexes; an accident index, safety management index, and safety culture index. Based on this study, a railway safety evaluation model will be developed in the next study.

• Journal of applied mathematics & informatics
• /
• v.38 no.1_2
• /
• pp.189-200
• /
• 2020

Let G be a simple connected graph with n vertices and m edges. Denote by d₁ ≥ d₂ ≥ ⋯ ≥ d_n > 0 and d(e₁) ≥ d(e₂) ≥ ⋯ ≥ d(e_m) sequences of vertex and edge degrees, respectively. If vertices v_i and v_j are adjacent, we write i ~ j. The general sum-connectivity index is defined as 𝒳_α(G) = ∑_i~j(d_i + d_j)^α, where α is an arbitrary real number. Firstly, we determine a relation between 𝒳_α(G) and 𝒳_α-1(G). Then we use it to obtain some new bounds for 𝒳_α(G).

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.17 no.32
• /
• pp.281-296
• /
• 1994

In this paper, a new index(joint index) which shows the higher confidence than that of the existing technical indices and has simple logical structure and an index which is an applied form of the existing index(OBV-I index) are proposed. The index characteristics which have been known are verified by choosing the three most used technical indices(ADR index, investment psychological rate and VR index) as samples. And the index characteristics of the joint index are compared to those of the OBV-I index. The comparisons are executed not by comparing the investment earning rate of each index but by calculating the unnecessary number of trade days in the total number of trade days according to the index.

• KIEAE Journal
• /
• v.12 no.2
• /
• pp.93-101
• /
• 2012

In this study, we measured the Index of Greeness(I.O.G) and analyzed factors that affect in downtown street of Seoul. The aim of this article is to provide an ways of improving I.O.G, with an emphasis on accuracy of measurement. We utilized the autimatic measurment techniques proposed by Tonosaki to solve the problem of accuracy in measurement. The result is as follows : Firstly, the average I.O.G of Gwanghwamun Plaza is 15.76%, Jongno is 11.48% and Dasanro(from Yaksu station to Beotigogae station) is 6.36%. According to the comprehensive analysis in three reseach areas, it shows that I.O.G is intimately linked with planting method, species of trees and the presence of wall planting. Secondly, it was analyzed that grass and ground-cover planting promote I.O.G better than other method. The I.O.G of photo which contains grass is 45.47%. According to the comparative analysis between tree planting and multi-planting method, the presence of lower planting showed a difference about 8.77% of I.O.G.. From the persipective of I.O.G, tree planting with two lines is more effective than one. The difference of two ways is about 3.24%. Thirdly, it is an efficint way to use the wall planting or vertical planting in order to promote I.O.G.. In Dasanro, The I.O.G of photo which contains wall planting or vertical planting is 45.47% in contrast to the average of I.O.G. is 6.36%. Fourthly, the difference of I.O.G between broadleaf tree and needleleaf tree was larger than we thought. If look closely confined to this study, the I.O.G of street planted by Pine is 3.61% and Eastern Sycamore Family Bottonwood is 12.55%.

• Journal of The Korean Association For Science Education
• /
• v.13 no.3
• /
• pp.310-316
• /
• 1993

One of the major characteristics in misconceptions is the stability over time. However, the concept of stability has not been defined clearly yet even though some trials to quantify the stability has been done. In this study, the researcher tried to establish a stability index of students' misconception for the quantification. In this study, the stability of a misconception was defined using mean correct choice (MC), the slope of correct choice (C), mean incorrent choice(MI) and the slope of incorrect choice(I) as follows; I=1/3 (1-C) (1+I)(1-MC)(1+MI). The index developed in the study was examined using artificial data. In this study, the index seemed to represent the charicteristics of the stability inferred by theoretically. This means the index developed in this study has some validity for the time being. Howerever, since artificial data were used to exame the index, it showed be reexamined using real data in the future study.