• KIPS Transactions on Computer and Communication Systems
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• v.5 no.10
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• pp.373-378
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• 2016

Recently, IPS(Indoor Positioning System) Technology has been progressing study and research, It has been studied in the fingerprinting and trilateration continuously. however because Fingerprinting and Trilateration Technology use AP(Access Point) for Positioning Calculation, Fingerprinting and Trilateration are not never had a credit positioning accuracy by using unstable RSSI in large scale. in this paper, to improve the problem about precise positioning in wide area, we introduced a concept of Sector including Cell. Sectors are not involved in each other and only fingerprinting calculation is proceed in a sector. we suggest this fingerprinting system considering efficiency and accuracy and compared to conventional fingerprinting, we demonstrated our system efficiency by mathematical techniques.

• Journal of the Korean School Mathematics Society
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• v.9 no.3
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• pp.309-316
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• 2006

This study examined the ambiguous using the terminology of statistics at mathematics textbook of highschool in Korea and proposed the correct using of sampling error and sampling distribution of sample mean with consistency. And this paper proposed that the concept of error have to teach in context of sampling action in school mathematics.

• Korean Management Science Review
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• v.32 no.4
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• pp.97-108
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• 2015

This study proposes a mathematical model to estimate the economic value of weather forecast service, among which the precipitation forecast service is focused. The value is calculated in terms of users' satisfaction or dissatisfaction resulted from the users' decisions made by using the precipitation probabilistic forecasts and thresholds. The satisfaction values can be quantified by the traditional value score model, which shows the scaled utility values relative to the perfect forecast information. This paper extends the value score concept to a collective value score model which is defined as a weighted sum of users' satisfaction based on threshold distribution in a group of the users. The proposed collective value score model is applied to the picnic scenario by using four hypothetical sets of probabilistic forecasts, i.e., under-confident, over-confident, under-forecast and over-forecast. The application results show that under-confident type of forecasts outperforms the others as a measure of the maximum collective value regardless of users' dissatisfaction patterns caused by two types of forecast errors, e.g., miss and false alarm.

• Journal of Educational Research in Mathematics
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• v.9 no.2
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• pp.473-491
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• 1999

The learning of mathematics happens in some situations. It is natural that students should learn mathematics in more appropriate situations. But, so far It has been hardly studied about concrete situation and milieu where math can be successfully taught. In today's math education, the situation of education as a external circumstance become realized more and more importantly with influence of open education. But they don't embody situation as an internal circumstance where the intrinsic concept of mathematics can be obtained. We started this thesis from this tried to answer it on the basis of Brousseau's question, have theory about the didactical situations. One of the purpose of this study is to understand the theory of didactical situations, which focuses on how we can elaborate situations which really make a mathematical notion function. In this study, It is attempted clarify some concepts of the theory of didactical situations. The other is to discuss about what the theory of didactical situations suggests us in math zeducation. The method of math teaching and learning and the teacher's role were discussed in the viewpoint of Brousseau's theory. Finally, We elaborated and presented some didactical situations which make the notion of the area of rectangle.

• Journal for History of Mathematics
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• v.19 no.3
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• pp.95-112
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• 2006

The purpose of this paper is to investigate a classic mathematician and inventor Archimedes' work ${\ll}$On the Sphere and Cylinder${\gg}$. The propositions of this book which deals with three dimensional geometry are reviewed. Through the review this study tries to find out how Archimedes mastered spherical figures and how classical mathematics ideas are related to the modern concept of integration. The results of this study seems to help people understand deeply modern mathematics and to be good resources to develop new mathematical ideas.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2551-2556
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• 2009

The principal operation of a ring laser gyroscope depends on the phase difference for the counter-propagating waves within a closed path. The reflection mirrors mounted on the resonator block form the traveling waves. Thus, the dimension accuracy of resonator block influences the traveling path of beam. In order to maintain the stable optical beam path in the ring resonator, the piezo-driven moveable mirror is adopted for the path length control under the thermal expansion or mechanical strain of resonator block. This paper presents the mathematical description of the elastic behavior of piezo-driven mirror. This description can be applied for the concept design of piezo-driven mirror.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.4
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• pp.16-22
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• 2019

After Dantzig and Rasmer introduced Vehicle Routing Problem in 1959, this field has been studied with numerous approaches so far. Classical Vehicle Routing Problem can be described as a problem of multiple number of homogeneous vehicles sharing a same starting node and having their own routes to meet the needs of demand nodes. After satisfying all the needs, they go back to the starting node. In order to apply the real world problem, this problem had been developed with additional constraints and pick up & delivery model is one of them. To enhance the effectiveness of pick up & delivery, hub became a popular concept, which often helps reducing the overall cost and improving the quality of service. Lots of studies have suggested heuristic methods to realize this problem because it often becomes a NP-hard problem. However, because of this characteristic, there are not many studies solving this problem optimally. If the problem can be solved in polynomial time, optimal solution is the best option. Therefore, this study proposes a new mathematical model to solve this problem optimally, verified by a real world problem. The main improvements of this study compared to real world case are firstly, make drivers visit every nodes once except hub, secondly, make drivers visit every nodes at the right time, and thirdly, make drivers start and end their journey at their own homes.

• Structural Engineering and Mechanics
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• v.49 no.3
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• pp.311-327
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• 2014

The safety relating to leakage of water and pitch instability of ship chambers of the full balanced hoist vertical shiplifts has been the focus of adoption of the type of vertical shiplifts. This paper aims to remove the doubts through theoretical and engineering researches. The leakage and pitch stability of ship chambers of full balanced hoist vertical ship lifts are investigated on the basis of theoretical analysis and exploration of engineering measures. Regarding the issue of leakage of ship chambers, a mathematical model on leaking process is built and corresponding formula and coping measures are obtained which can be applied in control program of ship lifts by linking with monitoring. The concept of safety grade is put forward to seek the best technical and economic index and the corresponding technical measures are for different grades of ship lift is suggested. For the issue of pitch instability, a methodology of combining theoretical deduction and summary of achievements of design and operation of the type of the full balanced hoist shiplifts is adopted, and the formula for design about pitch stability of ship chambers is derived.

• Particle and aerosol research
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• v.11 no.4
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• pp.99-105
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• 2015

The possible existence forms of particle aggregates in liquid medium are classified into four different types according to their morphological characteristics, including the single particles that are separated from each other, the linear aggregates in which all component particles are located in a line, the planar aggregates where all particles are arranged on a plane, and the volumetric aggregates where all particles forms a three-dimensional space. These particle aggregates with different space morphologies have different fractal dimensions and different influence on the rheological phenomena of the solid-liquid system. The effects of various aggregates on the suspension viscosity are analyzed and related with the particle concentration, and then a mathematical model is presented to determine the fractal dimensions of various aggregates by measuring the apparent viscosity of the solid-liquid system. In the model, the viscous fractal dimension is developed as a new concept, the fractal dimensions of different aggregates can be obtained separately and then the relative components of various aggregates experimentally analyzed.

• Journal of the Korea Institute of Building Construction
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• v.12 no.3
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• pp.358-368
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• 2012

On most construction sites, the arrangement of tower cranes is decided by site engineers based on their own experience, which can cause cost overruns and delays in the lifting work. Although many researchers have conducted studies on tower crane arrangement using computer modeling and knowledge-based expert systems as well as mathematical models, no research has aimed to develop an algorithm to identify an optimum solution among several alternatives for installation areas of tower cranes satisfying the conditions of lifting work. The objective of this study is to develop an automatic arrangement algorithm for tower cranes used in high-rise apartment construction. First, as a new concept, a possible installation area of tower cranes was suggested. Second, after proposing several alternatives based on the installation points suggested in this study, an algorithm analyzing the economic feasibility of tower cranes was developed considering the rental, installation and removal costs. Third, a case study was conducted to prove the validity of the developed algorithm for selecting and installing an effective set of tower cranes at minimum cost.