• Journal of the Korean GEO-environmental Society
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• v.10 no.3
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• pp.37-45
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• 2009

The experimental study was carried out to evaluate the characteristics of the point load index and the uniaxial compressive strength of inherently anisotropic shale in the laboratory. In the testing program the effects of size and the shape on the point load index were investigated both in the axial and diametral direction. In general, the point load index of the shale was constant when the length/diameter (L/D) ratio of the specimen is greater than 1.0 in the diametral direction. The point load index in axial direction shows slight decrease as the L/D ratio is increased and the corner breakage was observed when L/D ratio is greater than unity. The minimum point load index was observed in the bedding angle of $\beta=15^{\circ}{\sim}30^{\circ}$ in the axial point load tests and of $\beta=30^{\circ}$ in the uniaxial compression tests. The relationship between the point load index and the uniaxial compressive strength was linear to ${\sigma}_c=25.0 I_{s(50)}$ for the specimen with the bedding plane angle, $\beta$ at the range of $0^{\circ}{\sim}90^{\circ}$. On the other hand, this relationship was appeared linear to ${\sigma}_c=14.4 I_{s(50)}$ when the bedding angle, $\beta$ is fixed to 90${^{\circ}}$ and this correlation is much different from ${\sigma}c=22 I_{s(50)}, which is generally applied to the rock specimen with no bedding plane in ISRM (1985). The anisotropic strength with different $\beta$ angle shows the shoulder type and this can be suitably modelled by the corrected Ramamurthy'(1993)s equation with the index value of 'n' equal to 3.0.

• Journal of Wetlands Research
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• v.15 no.2
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• pp.233-250
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• 2013

Gradually or radically change how the characteristics of the climate characteristic using change point analysis for the precipitation indicators were investigated. Significantly the amount, extreme and frequency were separated by precipitation indicators, each indicator RIA(Rainfall Index for Amount), RIE(Rainfall Index for Extremes) and RIF(Rainfall Index for Frequency) was defined. Bayesian Change Point was applied to investigate changing over time of precipitation indicators calculated. As the result of analysis, precipitation indicators in South Korea was found to recently increase all indicators except for the annual precipitation days and 200-yr precipitation. RIA revealed that there was a very clear point of significance for the change in Ulleungdo, Relatively significant results for RIE were identified in Gumi, Jecheon and Seogwipo. Also, since the 1990s, an increase in the number of variation points, and the horizontal width of the fluctuation point was being relatively wider. Based on these results, rethink the precipitation on the assumption of stationarity was judged necessary.

• Tunnel and Underground Space
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• v.14 no.4
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• pp.261-268
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• 2004

The main objectives of this study are to investigate the anisotropic characteristics of rocks and to evaluate the relationships between physical properties. A series of experiments were performed in three mutually perpendicular directions for three rock types, which are granite, granitic gneiss and limestone. The relationships of measured physical properties were evaluated. The results of ultrasonic wave velocity measurement show that granite of three rock types gives the largest directional difference, and that the wave velocity in a plane parallel to a transversely isotropic one is dominantly faster than that in a subvertical or vertical plane. It implies that ultrasonic wave velocity for rock could be used as a useful tool for estimating the degree of anisotropy. The ratio of uniaxial compressive strength to Brazilian tensile strength ranges approximately from 13 to 16 for granite. from 8 to 9 for granite gneiss, and from 9 to 18 for limestone. The directional differences for granite and granitic gneiss are very small, and on the other hand, is relatively large for limestone. It is suggested that strength of rock makes quite difference depending on the rock types and loading directions, especially for the anisotropic rocks such as transversely isotropic or orthotropic rocks. The ratio of uniaxial compressive strength to point load strength index ranges from 18 to 20 for granite, from 17 to 19 for granitic gneiss, and from 21 to 24 for limestone. These results show that point load strength index makes also a difference depending on rock types and directions. Therefore. it should be noted that the ratio of uniaxial compressive strength to point load strength index could be applied to all rock types. Uniaxial compressive strength shows relatively good relationship with point load strength index, Schmidt hammer rebound value, and tensile strength. In particulat, point load strength index is shown to be the best comparative relationship. It is indicated that point load test is the most useful tool to estimate an uniaxial compressive strength indirectly.

• Communications of the Korean Mathematical Society
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• v.13 no.1
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• pp.29-36
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• 1998

We show that if M is a $II_1$-factor and a countable discrete group G acts outerly on M then Jones' index $[M:M^G]$ of a pair of $II_1^-factors is equal to the order $\mid$G$\mid$ of G. It is also shown that for a subgroup H of G Jones' index $[M^H:M^G]$ is equal to the group index [G:H] under certain conditions.

• Journal of the Korean Mathematical Society
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• v.36 no.5
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• pp.911-921
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• 1999

We define the coincidence index of pairs of maps p, f : $\widetilde{X}$ $\rightarrow$ X where p is a covering of a polyhedron X. We use a polyhedral transversality Theorem due to T. Plavchak. When p=identity we get the classical fixed point index of self map of polyhedra without using homology.

• Journal of the Korean Mathematical Society
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• v.34 no.1
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• pp.237-245
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• 1997

The fixed point index plays an important role in solving the positive solutions of nonlinear equations in ordered Banach spaces ([7], [10], [11], [14], [15]). Many authors have studied the existence problems of positive solutions of nonlinear equations for nonlinear mappings ([1]-[5], [7], [9], [10], [14], [15]).

• Journal of Digestive Cancer Research
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• v.10 no.2
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• pp.99-106
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• 2022

Clinical research ultimately aimed to promptly diagnose and prevent diseases through precise biomarker development. Finding the optimal cut-off point of a regularly measured biomarker can help its interpretation and ultimately help in disease investigation and diagnosis, more specifically in determining the presence of diseases. Therefore, this study aimed to use the characteristics of outcome variables in clinical research to explain how to determine the optimal cutoff point. The outcome variables can be divided into dichotomous, ordinal, and survival types. The optimal cut-off point can be determined by finding points that maximize the Youden index, extended Youden index, and log-rank statistics. This study will enable clinical researchers to accurately determine the optimal cut-off points for regularly measured biomarkers, thereby enabling prompt disease diagnosis for effective treatment.

• Communications of the Korean Mathematical Society
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• v.24 no.2
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• pp.247-263
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• 2009

In this paper we use degree and index theory to present new applicable fixed point theory for permissible maps.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.855-859
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• 2007

It is essential to obtain accurate and highly reliable streamflow data for water resources planning, evaluation and management as well as design of hydraulic structures. A new discharge estimation method, which is named 'non-dimensional velocity distribution and index-velocity method,' was proposed in this research. This method showed very close channel discharges which were calculated with the exiting velocity-area method. When velocity-area method is used to estimate channel discharge, it is required to observe point velocities at every desired point and vertical using a current meter like Price-AA. However 'non-dimensional velocity distribution and index-velocity method' is used, it become optional to observe point velocities at every desired point and vertical. But this method can not be applied for the cases of very complex and strongly asymmetric channel cross-sections because non-dimensional velocity distribution by entropy concept may be quite biased from that of natural rivers.

• Korean Journal of Health Education and Promotion
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• v.18 no.2
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• pp.1-26
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• 2001

This research is aimed to define how the depression, performing ability of IADL and muscular-skeletal pain of the Aged, according to their residential circumstance, sex and age, can affect the subjective health index and how all these are related and associated with. For the period of June 1 to July 31, 2000, in order to study and define how the depression, performing ability of IADL and muscular-skeletal pain are related to the subjective health index of the Aged, we have conducted an enquete through a direct interview with 693 persons over age sixty-five (65) in Daejon and in other adjacent areas, divided into three different residential types “The Aged living at home”, “The Aged living at welfare facilities” and “The Aged living alone”. We have studied all the data and information obtained through this enquete and have analyzed χ²-test, t-test, ANOVA, analysis of simple correlation, analysis of factor. by SPSS10.0/PC+. The results were as follows: Generally, the four (4) factors depression, IADL performing ability, muscular-skeletal pain and the subjective health index of the Aged, are a lot influenced by and related to their residential circumstance, their sex and their age. With regard to the depression of the Aged by their sex, it was analyzed that, on an average, the female-Aged gains 48.3 point which reflects comparatively the higher points and the female-Aged is more depressed. In analyzing depression of the Aged by their age, it appears that the Aged between eighty (80) to eight-four (84) years of age, gains 49.2 point which is the highest points and simultaneously we could realize that depression follows age, - the more the age gets, the more the depression is increased. In analyzing depression of the Aged by their residential type, it shows that “the Aged living alone” gains 50.9 point and is most depressed. With regard to the IADL performance of the Aged by their sex, it was analyzed that, on an average, the female-Aged gains 23.8 point, which shows the performance of the female-Aged is less independent. In addition, it was also found that the IADL performing ability is becoming less and less independent following their age increasing. In analyzing IADL performance by their residential type, it appears that “the Aged living at welfare facilities” gains the lowest 21.5 point and is least independent. We conclude that some assistances from others are required for the Aged living at welfare facilities in their performing IADL. With regard to the muscular-skeletal pain of the Aged by their sex, it was analyzed that, on an average, the female-Aged gains 3.0 point and the female-Aged suffers from this pain more severely. In analyzing this pain by their residential type, it was found that, on an average, the 3.0 point goes for “the Aged living alone”, which explains the Aged living alone is having the most serious pain. With regard to the subjective heath index of the all Aged participated in this research, the analysis indicates 8.8 point and this is considered as a general standard (7-10 point). In analyzing this index by their sex, the female-Aged gains 8.6 point only and it explains a lot of female-Aged consider they are not really healthy. In analyzing this index by their residential type, “the Aged living at welfare facilities” and “the Aged living alone” gain the comparatively lower point, -respectively 8.4 point for the Aged living at welfare facilities and 8.8 point for the Aged living alone. The Aged of these two residential types express they are obviously in a bad condition of health, which makes us think a lot. With regard to the factors affecting the subjective health index of the Aged, it was analyzed that this index can significantly be influenced by their depression, their pain, their age and by how much they are satisfied with their current living conditions, and also analyzed that the correlative relation certainly exists between the depression and pain, and the subjective health index, - that is, the more the depression and pain are serious, the lower the subjective health index indicates. As for the IADL, it appears that the IADL's relation with this index is not that significant and even not important.