• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06b
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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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• v.13 no.11
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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.

• The Korean Journal of Applied Statistics
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• v.22 no.1
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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.

• Journal of KIISE:Databases
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• v.30 no.2
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• pp.109-124
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• 2003

Although most commercial relational DBMSs Provide a graphical query language for the user friendly interfaces of the databases, few research has been done for graphical query languages in object databases. Expressing complex query conditions in a concise and intuitive way has been an important issue in the design of graphical query languages. Since the object data model and object query languages are more complex than those of the relational ones, the graphical object query language should have a concise and intuitive representation method. We propose a graphical object query language called GOQL (Graphical Object Query Language) for object databases. By employing simple graphical notations, advanced features of the object queries such as path expressions including set attributes, quantifiers, and/or methods can be represented in a simple graphical notation. GOQL has an excellent expressive power compared with previous graphical object query languages. We show that path expressions in XSQL(1,2) can be represented by the simple graphical notations in GOQL. We also propose an algorithm that translates a graphical query in GOQL into the textual object query with the same semantics. We finally describe implementation results of GOQL in the Internet environments.

• Tunnel and Underground Space
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• v.6 no.3
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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.

• Journal of Digital Convergence
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• v.12 no.5
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• pp.231-238
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• 2014

Graphical passwords using images have been developed to solve problems in text based password recognition. The basic recognition process scheme of graphical passwords is clicking certain points on the screen image in correct order. In this pre-developed method of graphical passwords the recognition will fail if the precise positions are not clicked. A new graphical password system called PassPositions is introduced in this paper. PassPositions is a new graphical password scheme which is using relative positions never used earlier graphical password schemes. PassPositions is a graphical password scheme based on universal design that everybody can use conveniently without regarding their physical conditions.

• Journal of Nutrition and Health
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• v.30 no.2
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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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• v.9 no.6
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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.

• Journal of the Korean Society of Safety
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• v.16 no.3
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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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• v.6 no.1
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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.