• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1996년도 Proceedings International Workshop on New Video Media Technology
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• pp.29-34
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• 1996

This paper proposes a new concept in video called Graphical Video. Graphical Video is a content-based and scalable video representation. A video consists of several elements such as moving images, still images, graphics, characters and charts. All of these elements can be represented graphically except moving images. It is desirable to transform these moving images graphical elements so that they can be treated in the same way as other graphical elements. To achieve this, we propose a new graphical representation of moving images using spatio-temporal clusters, which consist of texture and contours. The texture is described by three-dimensional fractal coefficients, while the contours are described by polygons. We propose a method that gives domain pool location and size as a means to describe cluster texture within or near a region of clusters. Results of an experiment on texture quality confirm that the method provides sufficiently high SNR as compared to that in the original three-dimensional fractal approximation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권11호
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• pp.5755-5772
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• 2019

Security is becoming more important as society changes rapidly. In addition, today's ICT environment demands changes in existing security technologies. As a result, password authentication methods are also changing. The authentication method most often used for security is password authentication. The most-commonly used passwords are text-based. Security enhancement requires longer and more complex passwords, but long, complex, text-based passwords are hard to remember and inconvenient to use. Therefore, authentication techniques that can replace text-based passwords are required today. Graphical passwords are more difficult to steal than text-based passwords and are easier for users to remember. In recent years, researches into graphical passwords that can replace existing text-based passwords are being actively conducting in various places throughout the world. This article surveys recent research and development directions of graphical password authentication systems in Korea. For this purpose, security authentication methods using graphical passwords are categorized into technical groups and the research associated with graphical passwords performed in Korea is explored. In addition, the advantages and disadvantages of all investigated graphical password authentication methods were analyzed along with their characteristics.

• 응용통계연구
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• 제22권1호
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• pp.189-195
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• 2009

A dynamic graphical procedure is suggested to estimate optimal response transformation parameter and a curvature function of covariates in the regression model. Augmented partial residual plot is chosen for specifying a curvature. The proposed method is compared with a different approach (Soo, 2007) and is investigated efficiency by applying it to the real and the artificial data. The method is also extended to the 3D graphical situations.

• 한국정보과학회논문지:데이타베이스
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• 제30권2호
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• pp.109-124
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• 2003

대부분의 상용 관계 DBMS(Database Management System)에서는 사용자 편의성을 위하여 SQL과 함께 그래픽 질의어를 제공하고 있으나, 객체 DBMS의 경우에는 그래픽 질의어에 관한 연구와 개발이 미흡한 실정이다. 그래픽 질의어에서는 복잡한 질의 조건을 간결하고도 직관적인 방법으로 표현하는 것이 중요한 이슈이다. 특히, 객체 DBMS는 관계 DBMS 보다 복잡한 데이타 모델과 객체 질의어를 제공하므로 그래픽 객체 질의어를 설계하고 구현할 때 간결성과 직관성을 유지하는 것이 더욱 중요하다. 본 논문에서는 인터넷 환경에서 원격지 객체 데이타베이스에 접근하여 자료를 검색하고 관리하는 그래픽 객체 질의어인 GOQL(Graphical Object Query Language)을 제안한다. GOQL은 그래픽 관계 질의어에서 다루지 않은 집합값 속성과 한정어 및 메소드를 포함한 길이가 2 이상인 경로를 간단한 그래픽 요소들로 시각화함으로써 간결성과 직관성을 높인다. 그리고 대표적인 객체 질의어인 XSQL(1,2)에서 사용하는 경로는 GOQL에서 제공하는 간단한 시각적 도구로 표현할 수 있음을 보인다. 또한, 논문에서는 GOQL의 그래픽 질의어를 텍스트 객체 질의어로 변환하는 알고리즘을 제안하고, 실제로 인터넷 환경에서 동작하도록 구현한 결과를 소개한다.

• 터널과지하공간
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• 제6권3호
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• pp.209-222
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• 1996

Shut-in pressure, reopenting pressure and fracture orientation are very important parameters to be evaluated precisely in in-situ stress measurement by hydraulic fracturing. Graphical methods on pressure-time curves have been conventionally used, even though these are seriously dependent on subjectivity of interpreters. So there have been many demands on new method to objectivity in determining parameters. We have developed integrated hydrofracturing data processing program (HYDFRAC), based on nonlinear regression analysis and can be invoked under the Window graphical user interface. HYDFRAC consiste of three routines, that is shut-in pressure routine, reopening pressure routine, and fracture delineation routine. Each of routines include independent modules according to parameter determination methods. Its application to field tests ensured both objectivity and facility in determining of hydraulic fracturing parameters. Determining shut-in pressures at each pressurization cycles, we adopted the exponential pressure-decay method(EPD method), the bilinear pressure-decay-rate method (PDR method), and the tangent intersection method in order to find the pressurization-cyclic tendency of shut-in pressures. The estimated pressure by PDR method exists in the range of the upper and lower values by EPD method, and lies near to the upper value more than the lower. Being the pressurization cycle increased, the range of upper and lower limits come to be stabilized gradually. By graphical superposition method and bilinear pressure-accumulated volume method, reopening pressures were determined. Vertical and inclined fracture attitudes were determined by applying the directional statistics and sinusoidal curve fitting, respectively. The results of evaluation of hydrofracturing parameters showed that statistical methods could enhance the objectivity better than graphical methods.

• 디지털융복합연구
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• 제12권5호
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• pp.231-238
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• 2014

텍스트 기반 패스워드 인증의 문제점을 해결하기 위해서 이미지를 사용하는 그래픽 패스워드가 발전 하였다. 기본적으로 그래픽 패스워드는 화면에 보이는 이미지 위의 정확한 점의 위치를 순서대로 선택(클릭)하여 인증을 처리하는 방식이다. 이러한 기존의 그래픽 패스워드 방식은 화면상의 정확한 지점을 선택하여 클릭하지 못하면 인식에 실패한다. 본 논문에서는 이러한 단점을 개선한 신 개념의 그래픽 패스워드 방식인 PassPositions를 소개한다. PassPositions는 지금까지의 그래픽 패스워드 방식에서 사용하지 않았던 상대위치를 패스워드 생성에 사용한 신개념의 그래픽 패스워드 기법이다. PassPositions는 유니버설 디자인에 기반을 둔 그래픽 패스워드 기법으로 사용자의 신체적 조건에 관계없이 모두가 편리하게 사용할 수 있다.

• Journal of Nutrition and Health
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• 제30권2호
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• pp.195-200
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• 1997

A graphical method to determine the anthropometric levels that's are lean, slightly lean, normal, slightly obese, obese by BMI, Broca and Rohrer indices was developed. On the graph of height vs. weight, regions corresponding to the anthropometric levels were separated by equations calculated with boundary conditions for BMI, Broca and Rohrer indices, respectivelyl. It was observed that the determinations of the anthropometric level was influenced by the weight to a larger extent than the hight, which magnitude was in the order of BMI>Broca>Rohrer. There appeared significant differences between the results of the anthropometric level for higher and weight by BMI, Broca and Rohrer indices, respectively. Conclusively, the graphical method was proved as a good means to analyze and compare the anthropometric levels from BMI, Broca and Rohrer indices.

• Journal of Power Electronics
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• 제9권6호
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• pp.854-865
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• 2009

Super-lift dc-dc converters are a series of advanced step-up dc-dc topologies that provide high voltage transfer gains by super-lift techniques. This paper presents a developed graphical modelling method for super-lift converters and gives a thorough analysis with a consideration of the effects caused by parasitic parameters and diodes' forward voltage drop. The general guidelines for constructing and deriving graphical models are provided for system analysis. By applying it to examples, the proposed method shows the advantages of high convenience and feasibility. Both the circuit simulation and experimental results are given to support the theoretical analysis.

• 한국안전학회지
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• 제16권3호
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• pp.53-60
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• 2001

This paper presents a graphical method for hazard assessment of electric shock by safety criteria. For the human body to be safety actual body current should not exceed safety criteria, i.e. allowable body current. The assessment method presented in this paper is based m the safety criteria of the IEEE Standard 80 as well as the IEC 479-1. The hazard can be assessed in terms of alterable touch voltages instead of alterable body current. Thus, the hazard assessment of given electric shock condition is referred to a procedure by which the actual touch voltages are compared with the allowable (safe) touch voltages. Since the IEC 479-1 safety criteria are nonlinear, the graphical method is presented for the hazard assessment. Body current and body voltage are calculated with the allowable touch voltage. A comparison of the safety criteria of two widely accepted standards, i.e. the IEEE Std 80 End the IEC 479-1 is proposed. Also Thevenin equivalent resistance is obtained from electric shock model expressed by two-port earth-grid-foot system. On the basis of calculated results, the allowable touch voltage, the body current and the body voltage we can conduct the hazard or safety assessment and estimate the severity of electric shock.

• Communications for Statistical Applications and Methods
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• 제6권1호
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• pp.1-10
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• 1999

When the component proportions in mixture experiments are restricted by lower and upper bounds multicollinearity appears all too frequently. The ridge regression can be used to stabilize the coefficient estimates in the fitted model. I propose a graphical method for evaluating the mixture component effects of ridge regression estimator with respect to the prediction variance and the prediction bias.