• Korean Journal of Digital Imaging in Medicine
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• v.17 no.1
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• pp.9-12
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• 2015

임상용 모니터의 출력값 중 가장 큰 영향을 주는 것이 휘도이다. 최근 컬러 모니터의 임상용 사용으로 인해 출력값의 보정은 매우 중요하게 관리되고 있다. 색보정 변위의 특성화가 휘도와 동일한 인자로 영향을 주는지 분석하기 위해 사용된 특성화 보정 모델은 GOG모델과 S-curve모델 이다. 두 개의 모델을 통해 모니터의 휘도는 장치의 출력과 직접적인 관계가 있다는 것을 증명하고 동일한 출력에 입력값을 가질 수 있도록 구성하고자 한다. 동일한 출력을 디스플레이 할 경우 동일한 출력값을 얻어야 한다. 그러나 모니터에 따라 서로 다른 출력값을 산출한다. 컬러모니터의 경우는 출력의 안정성에 휘도뿐만 아니라, 색감(R,G,B) 변화가 큰 역할을 수행한다. 본 연구에서는 분석인자 중 대조도에 영향을 주는 인자를 역추적하여 특성화 보정 S-curve모델을 LCD에 적용하였다. 이는 GOG모델을 적용한 CRT와 동일한 결과를 얻었다. 따라서 인자는 CIEXYZ의 결과값과 동일한 인자를 구할 수 있다.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.2 s.48
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• pp.1-10
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• 2006

Reinforced concrete bridge columns with relatively small aspect ratio show flexure-shear behavior, which is flexural behavior at initial and medium displacement stages and shear failure at final stage. Since the columns with flexure-shear failure have lower ductility than those with flexural failure, shear capacity curve models shall be applied as well as flexural capacity curve in order to determine ultimate displacement for seismic design or performance evaluation. In this paper, a modified shear capacity curve model is proposed and compared with the other models such as the CALTRANS model, Aschheim et al.'s model, and Priestley et al.'s model. Four shear capacity curve models are applied to the 4 full scale circular bridge column test results and the accuracy of each model is discussed. It may not be fully adequate to drive a final decision from the application to the limited number of test results, however the proposed model provides the better prediction of failure mode and ultimate displacement than the other models for the selected column test results.

• The KIPS Transactions:PartD
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• v.11D no.3
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• pp.597-604
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• 2004

Accurate software cost estimation is essential to both developers and customers. Most of the cost estimating models based on the size measure methods, such as LOC and FP, are obtained through size estimation. The accuracy of size estimation directly influences the accuracy of cost estimation. As a result, the overall structure of regression-based cost models applies the power function based on software size. Many growth phenomenon in nature such as the growth in living organism, performance of technology, and learning capability of human show an S-shaped curve. This paper proposes a model which estimates the developing effort by using the growth curve. The presented model assumes that the relation cost and size follows the growth curve. The appropriateness of the growth curve model based on Function Point, Full-Function Point and Use-Case Point, which are the general methods in estimating the software size have been confirmed. The proposed growth curve model shows similar performance with power function model. In conclusion, the growth curve model can be applied in the estimation of the software cost.

• The KIPS Transactions:PartD
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• v.11D no.7 s.96
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• pp.1451-1458
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• 2004

Current software reliability growth models based on Gompertz growth curve are all logarithmic type. Software reliability growth models based on logarithmic type Gompertz growth curve has difficulties in parameter estimation. Therefore this paper proposes a software reliability growth model based on the logistic type Gompertz growth curie. Its usefulness is empirically verified by analyzing the failure data sets obtained from 13 different software projects. The parameters of model are estimated by linear regression through variable transformation or Virene's method. The proposed model is compared with respect to the average relative prediction error criterion. Experimental results show that the pro-posed model performs better the models based on the logarithmic type Gompertz growth curve.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.6
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• pp.33-41
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• 2004

This paper proposes a color matching 3D look-up table simplifying the complex color matching procedure between a monitor and a mobile display device. In other to perform color matching, it is necessary to process color of image in the device independent color space like CIEXYZ or CIELAB. To obtain the data of the device independent color space from that of the device dependent RGB color space, we must perform display characterizations. LCD characterization error using S-curve model is larger than tolerance error since LCD is more nonlinear than CRT. This paper improves the S-curve model to have smaller characterization error than tolerance error using the electro-optical transfer functions of X, Y, and Z value. We obtained images having higher color fidelity on mobile display devices through color matching experiments between monitor and mobile display devices. As a result of this experiments, we concluded that the color matching look-up table with 64(4${\times}$4${\times}$4) is the smallest size allowing characterization error to be acceptable.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.9 no.1
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• pp.85-102
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• 1999

In this paper, we propose an EC-SRP(Elliptic Curve - Secure Remote Password) protocol that uses ECDLP(Elliptic Curve Discrete Logarithm Problem) instead SRP protocols’s DLP. Since EC-SRP uses ECDLP, it inherits the high performance and security those are the properties of elliptic curve. And we reduced the number of elliptic curve scalar multiplication to improve EC-SRP protocol’s performance. Also we have proved BC-SRP protocol is a secure AKC(Authenticated Key Agreement with Key Confirmation) protocol in a random oracle model.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.6 s.46
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• pp.41-52
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• 2005

The seismic damage assessment due io the postulated earthquake was attempted for the buildings in the model district of Seoul City. The model district was selected to represent the typical structural and residential characteristics of Seoul City. The buildings in the model district were classified into 11 structural types. For each structural type, the capacity and fragility curves were constructed with parameters presented in HAZUS. The ground motions due to the postulated earthquakes were artificially generated and ground response analyses were done for three kinds of soil profiles classified with respect to the depth of surface soil layer. The probability of damage state of each structural type was calculated using capacity spectrum method and fragility curve. Finally, the calculated results were translated into GIS database and mapped to evaluate the seismic damage in the model district.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.186-189
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• 2006

Since the columns with flexure-shear failure have lower ductility than those with flexural failure, shear capacity curve models shall be applied as well as flexural capacity curve in order to determine ultimate displacement for seismic design or performance evaluation. In this paper, a proposed modified shear capacity curve model is compared with the other models such as the CALTRANS model, Aschheim et al.'s model, and Priestley et al.'s model. Four shear capacity curve models are applied to the 4 full scale and 7 small scale circular bridge column test results and the accuracy of each model is discussed. It may not be fully adequate to drive a final decision from the application to the limited number of test results, however the proposed model provides the better prediction of failure mode and ultimate displacement than the other models for the selected column test results.

• Transactions of Materials Processing
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• v.7 no.3
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• pp.274-281
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• 1998

The service life of tools in metal forming process is to a large extent limited by wear, fatigue fracture and plastic deformation. In elevated temperature forming processes wear is the predominant factor for tool operating life. To predict tool life by wear Achard's model is generally applied. Usually hardness of die is considered to be a function of temperature. But hardness of die is a function of not only tem-perature but also operating time of die. To consider softening of die by repeated operation it is necessary to express hardness of die by a function of a function of temperature and time. By experiment of reheating of die softening curve was obtained and applied to suggest modified Archard's Model in which hardness is a function of main tempering curve.

• Journal of the Korean Geotechnical Society
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• v.20 no.7
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• pp.171-181
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• 2004

This study was conducted to explore the tensile strength models in granular soil at the full range of unsaturated state. Direct tension experiments were carried out with a newly developed direct tension technique. The measured experimental data were compared with theoretical models developed by Rumpf and Schubert for monosized ideal particulate solids at the unsaturated state. To do this, the soil-water characteristic curve obtained from a suction-saturation experiment was used to define the unsaturation state and the negative pore water pressure with different water content levels, which are important factors in theoretical tensile strength models. The nonlinear behavior of the tensile strength for unsaturated granular soil at the pendular state is appropriately simulated with Rumpf's model. For the funicular and capillary states, the predicted trend by Schubert's model is properly matched with the experimental data: tensile strength steadily increases and reaches a maximum value and then decreases until it reaches zero. This comparison supports the concept that the tensile strength of unsaturated real granular soil can be approximately simulated with theoretical models.