• Magazine of the Korean Society of Agricultural Engineers
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• v.21 no.4
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• pp.108-117
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• 1979

In order to obtain the basic data for design of water structures which can be contributed to the planning of water use. Best fitted distribution function and the equations for the probable minimum flow were derived to the annual minimum flow of five subwatersheds along Geum River basin. The result were analyzed and summarized as follows. 1. Type III extremal distribution was considered as a best fit one among some other distributions such as exponential and two parameter lognormal distribution by $x^2$-goodness of fit test. 2. The minimum flow are analyzed by Type III extremal distribution which contains a shape parameter $\lambda$, a location parameter ${\beta}$ and a minimum drought $\gamma$. If a minimum drought $\gamma=0$, equations for the probable minimum flow, $D_T$, were derived as $D_T={\beta}e^{\lambda}1^{y'}$, with two parameters and as $D_T=\gamma+(\^{\beta}-\gamma)e^{{\lambda}y'}$ with three parameters in case of a minimum drought ${\gamma}>0$ respectively. 3. Probable minimum flow following the return periods for each stations were also obtained by above mentioned equations. Frequency curves for each station are drawn in the text. 4. Mathematical equation with three parameters is more suitable one than that of two parameters if much difference exist between the maximum and the minimum value among observed data.

• Journal for History of Mathematics
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• v.30 no.4
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• pp.203-219
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• 2017

As is well known, the most important development in the history of Chinese mathematics is materialized in Song-Yuan era through tianyuanshu up to siyuanshu for constructing equations and zengcheng kaifangfa for solving them. There are only two authors in the period, Li Ye and Zhu Shijie who left works dealing with them. They were almost forgotten until the late 18th century in China but Zhu's Suanxue Qimeng(1299) had been a main reference for the Joseon mathematics. Commentary by Luo Shilin on Zhu's Siyuan Yujian(1303) was brought into Joseon in the mid-19th century which induced a great attention to Joseon mathematicians with a thorough understanding of Zhu's tianyuanshu. We discuss the history that Joseon mathematicians succeeded to obtain the mathematical structures of Siyuan Yujian based on the Zhu's tianyuanshu.

• Journal of KSNVE
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• v.7 no.6
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• pp.993-1000
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• 1997

This paper presents a new technique of mathematical treatment using a finite element model for analyzing the vibration of the towed line array. Since the towed line array has the axisymmetricity, axisymmetric elements are used in finite element modeling for the towed array structure. The fluid-structure interaction is also considered. The array consists of a series of identical substructures which can include internal structures such as spacers, hydrophones and ropes. That periodicity of substrucutres permits the substructure synthesis technique using characteristic wave guide for analyzing the response of towed array system. This synthesis technique can reduce the cost of computing the array response. It is suggested that a response of towed array can be computed by the finite element method and substructure synthesis technique using wave guide. Several experiments for towed array were performed to verify the present computation technique. The predicted vibration for the towed array shows good agreement with the measured result.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.3 s.180
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• pp.187-194
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• 2006

Unexpected postoperative changes, such as growth in rib hump and shoulder unbalance, have been occasionally reported after corrective surgery for scoliosis. However there has been neither experimental data fer explanation of these changes, nor the suggestion of optimal correction method. Therefore, the numerical study was designed to investigate the post-operative changes of vertebral rotation and rib cage deformation after the corrective surgery of scoliosis. A mathematical finite element model of normal spine including rib cage, sternum, both clavicles, and pelvis was developed with anatomical details. In this study, we also developed a special program which could convert a normal spine model to a desired scoliotic spine model automatically. A personalized skeletal deformity of scoliosis model was reconstructed with X-ray images of a scoliosis patient from the normal spine structures and rib cage model. The geometric mapping was performed by translating and rotating the spinal column with an amount analyzed from the digitized 12 built-in coordinate axes in each vertebral image. By utilizing this program, problems generated in mapping procedure such as facet joint overlapping, vertebral body deformity could be automatically resolved.

• Journal of Wellbeing Management and Applied Psychology
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• v.3 no.2
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• pp.21-26
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• 2020

The purpose of this article is to capture this situation within the changes that take place due to it, inside the Greek society where there is a great need for professional social workers who are able to work targeted and effectively with foreigners, both children and adults, who have or develop mental health problems for the very first time. Over the recent decades the increasing number of migration flows has exerted and continues to exert great pressure on the health system and on the welfare structures of Greece. The bases for the development of a rudimentary reception and integration system that still is in progress have been delayed, while there has been no happy medium, between the enormous pressure that foreigner users of this system put on, and the humanitarian obligation of a well-governed state towards all residents of the country. Straight through everyday clinical practice in the field of intercultural work, social work has the knowledge and techniques for a total management of emerging problems and at the same time provides a value system with an ethical background which approaches refugees and migrants in order to provide quality services, mostly to users of mental health services.

• Journal of Biomedical Engineering Research
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• v.31 no.6
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• pp.472-480
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• 2010

Mechanically deformed cartilage undergoes a temperature dependent phase transformation resulting in reshaping of cartilage. Laser-assisted cartilage reshaping (LCR) is recently introduced to recreate the underlying cartilage framework in structures such as ear, larynx, trachea, and nose. However, this procedure has not been fully supported by confirmed efficacy because of the lack of scientific research and its safety issues. The purpose of this study is to evaluate current laser sources to determine optimal laser wavelength for LCR using mathematical simulations and investigate optical, thermo-mechanical, and backscattering properties of cartilage after laser irradiation. The results showed that 1444 nm wavelength was effective for reshaping of cartilage with minimal thermal damage in the surrounded tissues by monte carlo simulations. Analysis of bend angle changes, thermo-mechanical characteristics, and backscattered properties may be useful to better identify the biophysical transformation responsible for stress relaxation in cartilage and develop an optical feedback control methodologies.

• Journal of KIISE:Software and Applications
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• v.37 no.10
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• pp.745-750
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• 2010

To effectively retrieve mathematical documents including various equations, mathaware search engines are needed. In this paper, we propose a equation retrieval system which helps users effectively search structurally similar equations. The proposed system disassembles MathML equations into three types of heterogeneous indexing terms; operators, variables, and partial structures of equations. Then, it independently indexes the disassembled terms. When a user inputs a MathML equation, the proposed system searches and ranks equations using weighted sums of three language models for the heterogeneous indexing terms. In the experiments with 244,744 MathML equations, three proposed system showed reliable performances (a P@1 of 53% in the closed test and a P@1 of 63% in the open test).

• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.117-125
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• 2012

In recent years, polymer concrete based on polyester resin have been widely generalized and the research of polymer concrete have been actively pursued by the technical innovations. Polymer concrete is a composite consisting of aggregates and an organic resin binder that hardens by polymerization. Polymer concrete are stronger by a factor of three or more in compression, a factor of four to six in tension and flexural and a factor of two in impact when compared with portland cement concrete. In view of the growing use of polymer concrete, it is important to study the physical characteristics of the material, emphasizing the short term properties as well as long term mechanical behavior. If polymer concrete is to be used in flexural load-bearing application such as in beam, it is imperative to understand the deformation of the material under sustained loading conditions. This study is proposed to empirical and mechanical model of polymer concrete tension creep using long-term experimental results and mathematical development. The test results showed that proposed model has been used successfully to predict creep deformations at a stress level that was 20 percent of the ultimate strength and viscoelastic behavior of recycled-PET polymer concrete is linear of stress level up to 30 percent. It is expected that the present model allows more realistic evaluation of varying stresses in polymer concrete structures with a constant loading.

• Computers and Concrete
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• v.9 no.5
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• pp.327-340
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• 2012

The search for a design that meets both performance and safety, with minimal cost and lesser environmental impact was always the goal of structural engineers. In general, the design of conventional reinforced concrete structures is an iterative process based on rules of thumb established from the personal experience and intuition of the designer. However, such procedure makes the design process exhaustive and only occasionally leads to the best solution. In such context, this work presents the development and implementation of a mathematical formulation for obtaining optimal sections of reinforced concrete columns subjected to uniaxial flexural compression, based on the verification of strength proposed by the Brazilian standard NBR 6118 (ABNT 2007). To minimize the cost of the reinforced concrete columns, the Simulated Annealing optimization method was used, in which the amount and diameters of the reinforcement bars and the dimensions of the columns cross sections were considered as discrete variables. The results obtained were compared to those obtained from the conventional design procedure and other optimization methods, in an attempt to verify the influence of resistance class, variations in the magnitudes of bending moment and axial force, and material costs on the optimal design of reinforced concrete columns subjected to uniaxial flexural compression.

• Steel and Composite Structures
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• v.14 no.2
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• pp.133-153
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• 2013

The concrete-filled steel tube (CFT) columns have several benefits of high load-bearing capacity, inherent ductility and toughness because of the confinement effect of the steel tube on concrete and the restraining effect of the concrete on local buckling of steel tube. However, the experimental research into the behavior of square CFT columns consisting of high-strength steel and high-strength concrete is limited. Six full scale CFT specimens were tested under flexural moment. The CFT columns consisted of high-strength steel tubes ($f_y$ = 325 MPa, 555 MPa, 900 MPa) and high-strength concrete ($f_{ck}$ = 80 MPa and 120 MPa). The ultimate capacity of high strength square CFT columns was compared with AISC-LRFD design code. Also, this study was focused on investigating the effect of high-strength materials on the structural behavior and the mathematical models of the steel tube and concrete. Nonlinear fiber element analyses were conducted based on the material model considering the cyclic bending behavior of high-strength CFT members. The results obtained from the numerical analyses were compared with the experimental results. It was found that the numerical analysis results agree well with the experimental results.