• Journal of KIISE:Computer Systems and Theory
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• v.29 no.8
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• pp.484-492
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• 2002

We propose an efficient stream authentication scheme using tree authentication. To reduce the computation cost of the sender, we design the authentication tree whose height is very short. We appropriately distribute authentication information over packets so the receiver can verify data with high probability. Moreover, we provide mathematical analysis on the verification probability. For the proposed scheme and previous schemes, we measured the elapsed time for generating authentication information and the proposed scheme has equal to or slightly larger than that of GM's scheme, which has the lowest computation overhead. We performed simulations, which show that the verification probability of the proposed scheme is much higher than that of any other scheme.

• ETRI Journal
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• v.25 no.5
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• pp.401-406
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• 2003

A biometric system determines the identity of a person by measuring physical features that can distinguish that person from others. Since biometric features have many variations and can be easily corrupted by noises and deformations, it is necessary to apply machine learning techniques to treat the data. When applying the conventional machine learning methods in designing a specific biometric system, however, one first runs into the difficulty of collecting sufficient data for each person to be registered to the system. In addition, there can be an almost infinite number of variations of non-registered data. Therefore, it is difficult to analyze and predict the distributional properties of real data that are essential for the system to deal with in practical applications. These difficulties require a new framework of identification and verification that is appropriate and efficient for the specific situations of biometric systems. As a preliminary solution, this paper proposes a simple but theoretically well-defined method based on a statistical test theory. Our computational experiments on real-world data show that the proposed method has potential for coping with the actual difficulties in biometrics.

• The KIPS Transactions:PartD
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• v.10D no.7
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• pp.1189-1196
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• 2003

Owing to the developed If industry, many people are more and more interested in Workflow which is an automated business processing system. In this paper, we present basic structures and various parallel processing structures of a workflow using EMFG (Extended Mark Flow Graph) that makes conceptional design available. And then, We design a workflow with EMFG. We propose the commitability verification method to check whether a workflow can complete or not and the logical bug verification method to find whether invalid components exist or not by using simulation result of it. The proposed EMFG modeling and analysis method for a workflow make it possible to become a visual and formal design. Also, it makes intuitional and mathematical analysis possible.

• Human Ecology Research
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• v.53 no.1
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• pp.29-47
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• 2015

The purpose of this study is to conceptualize the definition of school readiness specific to the context of the Republic of Korea. The school readiness test can be used as basic data to enable early childhood educational institutes to determine the general readiness of preschoolers and provide support to fit individual characteristics. For this purpose, six stages of the school readiness development process were considered, that is, draft development, primary preliminary survey, primary expert verification, secondary expert verification, secondary preliminary survey, and main survey. In the main survey, tests were conducted using the school readiness final draft targeting 344 preschoolers living in Seoul and Gyeonggi-do. The item discrimination power analysis and factor analysis for the examination area and question area were also conducted. Consequently, a test tool was developed on the basic of the results obtained, consisting of 129 items in the five areas of knowledge, function, adaptation, tendency, and attitude. The knowledge area was divided into general, linguistic, and mathematical knowledge, and the function area into fine motor function, basic living ability, expressive function, and gross motor function. The adaptation area was classified into adaptation activity, separation anxiety, maladaptive behavior, and environment adaptation; the tendency area into learning tendency; others understanding, and individual tendency, and the attitude area into rule compliance and life habits.

• The Journal of Korea Robotics Society
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• v.14 no.3
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• pp.191-195
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• 2019

This paper presents a rope modeling and verification for the robotic platform of the wall cleaning robot (ROPE RIDE). ROPE RIDE has the characteristics of climbing up and down using a rope fixed on the roof like traditional workers. In order to perform a stable operation with a wall cleaning robot, it is necessary to estimate the position of the robot in a vertical direction. However, due to the high coefficient of extension and nonlinearity of the climbing rope, it is difficult to predict the behavior of the rope. Thus, in this paper, the mathematical modeling of the rope was carried out through the preliminary experiment. Extensive experiments using different types of rope were used to determine the parameters of the constitutive equation of climbing ropes. The validity of the determined parameters of various ropes was verified through the experiment results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5323-5329
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• 2013

Many companies have tried to develop the horizontally vibrating linear motor, for sliming the smart phone. Mathematical modeling and analysis is one of method to simulate the dynamic performance of the horizonatally vibrating linear motor. However, the horizontally vibrating linear motor vibrates in twisting mode because there are two kinds of force acting on the vibrating part. One is are the horizontal force by Lorentz force. The other is the vertical force by attraction force between magnet of vibrating part and bracket and the gravity force of vibrating part. However, those are very difficult to be included in mathematical modeling which generate the simulation errors. In this paper, we perform MFBD (multi flexible body dynamics) simulation using commercial dynamic analysis program "DAFUL". In our new model, the force effects those are neglected in mathematical model, are included. For the verification, the simulation results are compared with the experiment results with manufactured prototype.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.9
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• pp.916-922
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• 2009

Because thermal design of satellite carrying out mission in space is performed by thermal analysis result using thermal mathematical model, accuracy of thermal mathematical model is important and it can be improved by model correlation. Correlation steps of satellite thermal math model are composed of modeling of satellite configuration placed in thermal vacuum chamber, verification of correspondence between thermal math model and real satellite configuration, and adjustment of modeling parameters from major part to minor part etc. In this study, correlation success criteria was established and correlation for satellite thermal math model was performed using result of thermal vacuum test of satellite structure-thermal model to meet the success criteria. The overall results satisfied the criteria and this correlated thermal model was applied for detailed thermal design of satellite.

• Journal of Elementary Mathematics Education in Korea
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• v.14 no.3
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• pp.745-768
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• 2010

The purpose of this study at gifted students' solving ability of the given study task by using all knowledge and tools which encompass mathematical contents and curriculums, and developing the teaching learning materials of gifted students in accordance with their level which tan enhance their mathematical thinking ability and develop creative idea. With these considerations in mind, this paper sought for the standard and procedures of teaching learning materials development according to the levels for the education of the mathematically gifted students. presented the procedure model of material development, produced teaching learning methods according to levels in the task of figurate number, and developed prototypes and examples of teaching learning materials for the mathematically gifted students. Based on the prototype of teaching learning materials for the gifted students in mathematics in accordance with their level, this research developed the materials for students and materials for teachers, and performed the modification and complement of material through the field application and verification. It confirmed various solving processes and mathematical thinking levels by analyzing the figurate number tasks. This result will contribute to solving the study task by using all knowledge and tools of mathematical contents and curriculums that encompass various mathematically gifted students, and provide the direction of the learning contents and teaching learning materials which can promote the development of mathematically gifted students.

• Journal of the Korea Society for Simulation
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• v.27 no.3
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• pp.23-36
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• 2018

Discrete Event System Specification (DEVS) has been used for decades as it provides sound semantics for hierarchical modular specification of discrete event systems. Instead of the mathematical specification, the DEVS diagram, based on the structured DEVS formalism, has provided more intuitive and convenient representation of complex DEVS models. This paper proposes a clean room process for implementation and verification of a DEVS diagram model specification into a simulation software source code. Specifically, it underlies a sequence of transformation steps from conformance and integrity checking of a given diagram model, translation into a corresponding tabular model, and finally conversion to a simulation source code, with each step being inversely verifiable for traceability. A simple example helps developers to understand the proposed process with associated transformation methods; a case study shows that the proposed process is effective for and adaptable to practical simulation software development.

• School Mathematics
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• v.5 no.4
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• pp.459-476
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• 2003

Internet was introduced to this study for making mathematics class the surroundings where students can solve the mathematics problems and communicate mathematically in a free way without restriction of time and place. With the intention of investigating mathematical communication and problem solving in mathematics education using internet, the objects of this study were determined as follows: First, how does a student express mathematical idea in problem solving using internet\ulcorner Second, is there any difference in the degree of participation of mathematical communication according to schoolwork accomplishment and characteristics of the student\ulcorner Third, what's the effect of class using internet on problem solving of mathematics class\ulcorner A case study was executed for the solution and the subjects were all students(44 persons) of a class in the fourth grade of elementary school in D city got into web-site of internet and had class with it and 8 students out of them were deeply analyzed. Their results were shown on internet, and eight of them had interview for deep research after survey with questionnaires for all of the students after class. The results and the conclusions of this study were as follows: First, it showed that there was various types(simple statement, fact enumerating, logical thinking, using letters and formula, insufficiency of explanation) of the mathematical idea expression in internet according to students and study using internet seems to be helpful to the improvement of logical his own expression through other students' expression. Second, it showed that there was difference in mathematical communication participation according to the student's characteristics and it helped students of poor schoolwork be interested and confident in mathematics. Third, it showed that pattern study using internet had effect on forming a habit of reason and verification in problem solving in mathematics class. Accordingly, pattern study using internet seems to have a positive effect on increasing mathematical interests and solving problems in mathematics class.