• Journal of Periodontal and Implant Science
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• 제39권4호
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• pp.399-405
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• 2009

Purpose: This article is purposed to present the correct statistic method by pointing out the statistical errors after analyzing the method of articles that were published in Korean Academy Journal of Periodontology and made statistic processes in them. Methods: 488 science papers which being put in Korean Academy Journal of Periodontology published from 2000 to 2006 was divided according to year. Results: In the 308 articles that applied statistic methods, 59 articles (50.0%), the largest portion of all, were included the case that applied incorrect parametric statistic method when needed to apply parametric statistics and 38 articles (32.2%) were included in the case that applied incorrect parametric statistic method when needed to apply non-parametric statistics. Conclusions: It is necessary to present the cases of inappropriate statistical methods in order to improve the quality of academic researches. Also, to apply adequate methods of statistics, it is suggested to report the articles periodically which are comparing and analyzing the statistical methods that are applied in the international articles in periodontal field.

• 한국컴퓨터정보학회논문지
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• 제6권4호
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• pp.146-153
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• 2001

본 논문에서는 웹 페이지 운영자가 웹 서버에 패스워드로 보호된 웹 영역을 배치시키는데 편리함을 제공하는 목적으로 새로운 패스워드 인증 방안을 제안한다. 이 방법에 따라 웹 영역은 접근 제한된 웹 페이지가 저장된 웹서버의 보안 디렉토리에 연결된다. 패스워드는 보안 디렉토리의 이름을 생성하는데 사용되며, 자바스크립트 코드는 보안 디렉토리영역 외부의 인증 웹 페이지에 포함된다. 이 스크립트 코드는 사용자가 입력한 패스워드를디렉토리 이름으로 변환시키고, 보안 디렉토리 내부의 접근 제한된 웹 페이지를 지시하는 완전한 URL을 형성한다. 따라서, 패스워드를 아는 사용자만이 유효한 URL을 구성할 수 있고, 접근 제한된 웹 페이지를 검색할 수 있다. 이 방법에 따라, 웹 페이지 운영자는 서버 독립적인 방식으로 패스워드로 보호된 웹 영역을 배치할 수 있다.

• 한국항공우주학회지
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• 제33권9호
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• pp.73-80
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• 2005

본 논문은 피치 바이어스 모멘텀 방식을 사용하는 HAUSAT-2 위성의 모멘텀 휠 초기구동(Start-up)을 위한 방안을 연구 분석하고 초소형위성 HAUSAT-2에 적합한 새로운 초기구동 방법을 제안하였다. HAUSAT-2는 25kg급의 나노 위성으로 모멘텀 휠과 마그네틱 토커를 사용하여 3축 제어를 수행한다. 자세제어를 위해 모멘텀 휠은 공칭 속도로 회전하거나 회전속도가 변하게 된다. 모멘텀 휠을 장착한 위성에서 휠의 초기구동방법은 휠을 발사 전에 미리 일정한 속도로 회전하게 하거나, 궤도상에서 추력기와 같은 구동기로 자세를 안정화 시킨 이후에 휠을 공칭속도에 도달하게 하는 방법이 있다. 하지만 HAUSAT-2와 같은 초소형위성의 경우 전력제한으로 발사 전 휠을 구동하기 힘들며, 궤도상에서 자세 안정화 이후 휠을 구동하기 위해서는 자기토커만으로 자세를 안정화 해야 하는데 이 경우 시간이 오래 걸리는 단점이 있다. 따라서 본 논문에서는 좀더 빠르고 효율적으로 휠의 초기구동과 자세안정화를 하기 위해서 모멘텀 휠 구동 방안을 제안하였다. 이 방법은 위성이 발사체에서 분리된 후 초기 각속도 제어를 할 때 일정한 속도 증가율로 모멘텀 휠의 속도를 올려주어 공칭 속도에 도달하게 하며, 이 후 자세 안정화를 수행하게 된다. 이 방식을 사용하면 약 4 궤도 이내에 휠 초기구동과 자세 안정화를 성공적으로 이룰 수 있음을 확인 할 수 있었다.

• 한국환경과학회지
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• 제1권2호
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• pp.137-144
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• 1992

Flocculation-spectrophotometry and streaming current detector( SCD ) method were investigated and compared in order to determine the optimum dosages of synthetic cationic polymers of different charge density and molecular mass for the removal of humic acid. The optimum dosage for each of the polymers was determined with the dosage at which the lowest absorbance of humic acid was shown for the formal. and was determined with the dosage required during charge neutralization of humic acid for the latter It was in good agreement between both methods and there is a strong inverse correlation between the optimum dosage and charge density of the polymers, with highly charged polymer giving the lowest optimum dosage, pointing out the importance the charge neutralization. By flocculation-spectrophotometry, it was found that the absorbance of humid acid with the amount of each of the polymers dosed, changes sharply for polymers of high charge density, but changes rather broadly for polymers of low and middle charge density, Both methods showed that a stoichiometric correlation exists between the optimum dosage of each of the cationic polymers and the negatively charged humic acid.

• Structural Engineering and Mechanics
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• 제34권6호
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• pp.739-753
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• 2010

Pointing to the design requirement of prestressed space grid structure being the target cable force, the pretension scheme decision analysis method is studied when there's great difference between structural actual state and the analytical model. Based on recursive formulation of cable forces, the simulative recursive system for pretension process is established from the systematic viewpoint, including four kinds of parameters, i.e., system initial value (structural initial state), system input value (tensioning control force scheme), system state parameters (influence matrix of cable forces), system output value (pretension accomplishment). The system controllability depends on the system state parameters. Based on cable force observation values, the influence matrix for system state parameters can be calculated, making the system controllable. Next, the pretension scheme decision method based on cable force observation values can be formed on the basis of iterative calculation for recursive system. In this way, the tensioning control force scheme that can meet the design requirement when next cyclic supplemental tension finished is obtained. Engineering example analysis results show that the proposed method in this paper can reduce a lot of cyclic tensioning work and meanwhile the design requirement can be met.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제1권2호
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• pp.137-144
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• 1997

Flocculation-spectrophotometry and streaming current detector(SCD) method were investigated and compared in order to determine the optimum dosages of synthetic cationic polymers of different charge density and molecular mass for the removal of humic acid. The optimum dosage for each of the polymers was determined with the dosage at which the lowest absorbance of humic acid was shown for the former and was determined with the dosage required during charge neutralization of humic acid for the latter. It was in good agreement between both methods and there is a strong inverse correlation between the optimum dosage and charge density of the polymers, with highly charged polymer giving the lowest optimum dosage, pointing out the importance the charge neutralization. By flocculation-spectrophotometry, it was found that the absorbance of humic acid with the amount of each of the polymers dosed, changes sharply for polymers of high charge density, but changes rather broadly for polymers of low and middle charge density. Both methods showed that a stoichiometric correlation exists between the optimum dosage of each of the cationic polymers and the negatively charged humic acid.

• International Journal of Advanced Culture Technology
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• 제10권4호
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• pp.102-109
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• 2022

In order to explore the characteristics that are more suitable for the physical and mental development of young people, enrich the existing martial arts teaching material system. Through the literature method, experimental method, questionnaire method and other research methods, the teaching comparison experiment of martial arts textbooks in primary and secondary schools was carried out, and the attitudes of martial arts courses at different ages in primary and secondary schools were analyzed. For different types of martial arts teaching materials, primary school students are more fond of them than junior high school students, and students of different ages also have different degrees of love for the four types of martial arts teaching materials, pointing out that it is necessary to carry out the reform of martial arts teaching materials as soon as possible, improve the difficulty, teach martial arts skills and knowledge in the combination of attack and defense, and reduce the trend of gymnastics; adjust and improve the periodicity, pertinence and diversity of martial arts teaching materials; mobilize students' enthusiasm for learning, cultivate students' interest in martial arts, and promote the inheritance of martial arts In the process of martial arts teaching, students' sense of identification with traditional Chinese culture is enhanced, and cultural self-confidence is enhanced.

• Structural Engineering and Mechanics
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• 제89권2호
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• pp.135-153
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• 2024

In this study, the impact response of a nanobeam with a moving nanoparticle is investigated. Timoshenko beam theory is used to model the nanobeam behavior and nonlocal elasticity theory is used to consider the effects of small dimensions. The interaction between the nanoparticle and nanobeam has been described using Lennard-Jones potential theory and the equations are discretized by the radial basis meshless method and a mathematical model is presented for the nanobeam-nanoparticle system. Validation of the proposed model is achieved by comparing the obtained natural frequencies with reference values, demonstrating good agreement. Dimensionless frequency analysis reveals a decrease with increasing nonlocal parameter, pointing out a toughening effect in nanobeam. The dynamic response of the nanobeam and nanoparticle is obtained by time integration of equations of motion using Newmark and Wilson-𝜃 methods. A comparative analysis of the two methods is conducted to determine the most suitable approach for this study. As a distinctive aspect in this study, the analysis incorporates the deformation of the nanobeam resulting from the nanoparticle-nanobeam interaction when calculating the Lennard-Jones force in the nanobeam-nanoparticle system. The numerical findings explore the impact of various factors, including the nonlocal parameter, initial velocity, nanoparticle mass, and boundary conditions.

• 한국군사과학기술학회지
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• 제16권2호
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• pp.154-159
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• 2013

Alignment tolerance for EO/IR airborne camera using common optic is an important factor in stabilization accuracy and geo-pointing accuracy. Before airborne camera is mounted on the aircraft, defining alignment tolerance and verification of it is essential in production as well as research and development. In this paper we establish basic concept on the definition and elements of alignment tolerance for airborne camera and propose how to measure each of those elements. Components and the measurement sequence of alignment tolerance are as follows: 1) tolerance of alignment between EO and IR LOS. 2) tolerance of sensor alignment. 3) tolerance of position reporting accuracy. 4) tolerance of mount alignment

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.876-881
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• 2003

Reliable attitude estimation during the launch and early orbit phase is a critical issue for a satellite. Typically gyroscopes and other sensors are utilized to estimate the attitude during this phase. It is difficult to estimate the attitude quickly and reliably using gyroscopes because it requires a large computational load and accurate sensor measurements. Furthermore, the gyroscope failure may lead to the loss of the satellite. This paper suggests a simple attitude estimation method of a low earth orbit satellite without using gyroscopes, but only using sun sensors and magnetometers in the sun-acquisition mode. Using Kompsat-I telemetry data, we verified that the suggested algorithm provides attitude estimation within 3 degrees on each axis.