• 대한전자공학회논문지
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• 제25권1호
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• pp.49-55
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• 1988

To provide a quantitative parameter of evaluating diagnosis of the liver diseases accurately, the ultrasonic attenuation coefficient was estimated from liver phantoms, 15 normal human livers and 30 liver disease patients. Two kind of phantoms(No.1: 1552m/s, No.2: 1562m/s) which have velocity (1560m/s) similar to that in human liver were constructed and their ultrasonic attenuation coefficients were determined. In this paper the spectral-shift approach and spectral-difference approach were used for estimating ultrasonic attenuation coefficient, \ulcornerdB/Cm.MHz). These two approaches were utilized to esitmate for 15 normal humans without any liver disease and 30 liver disease patients. The results indicate that the two types of phantoms produce the value of near the suggested value of 0.5 and the attenuation coefficients of hepatoma, normal liver, corrhosis, fatty liver and hepatitis show decreasing value in order named, suggesting that the present study can be of clinical value incorrelating the estimated attenuation coefficidents with the liver diseases.

• Journal of applied mathematics & informatics
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• 제36권3_4호
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• pp.331-348
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• 2018

In this paper, an initial value method for solving a class of singularly perturbed delay differential equations with layer behavior is proposed. In this approach, first the given problem is modified in to an equivalent singularly perturbed problem by approximating the term containing the delay using Taylor series expansion. Then from the modified problem, two explicit Initial Value Problems which are independent of the perturbation parameter, ${\varepsilon}$, are produced: the reduced problem and boundary layer correction problem. Finally, these problems are solved analytically and combined to give an approximate asymptotic solution to the original problem. To demonstrate the efficiency and applicability of the proposed method three linear and one nonlinear test problems are considered. The effect of the delay on the layer behavior of the solution is also examined. It is observed that for very small ${\varepsilon}$ the present method approximates the exact solution very well.

• 환경영향평가
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• 제22권6호
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• pp.659-665
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• 2013

Most of dredged soil generating millions of tons per year is treated as a waste disposing in ocean or landfill except some part of recycling. The purpose of this study is to present the prerequisite for the use of dredged soil as a resource and analyse economic and environmental values of the recycling of dredged soil. The analysis of the economic and environmental value of recycling of dredged soil as a resource showed that several trillion won of budget can be saved in construction of disposal area or landfill and that loss of about 50 million tons of aggregates from deforestation can be restored by supplyment of dredged soil preserving a mountain as big as the Namsan(Mt.) every year. In order to utilize dredged soil in more diverse areas as high value of resource, the related domestic laws are needed to be readjusted integrating laws spreaded in different government departments and a special law is prepared and enacted.

• 한국정보처리학회논문지
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• 제7권5호
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• pp.1419-1425
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• 2000

When we predict of software reliability, we can't know the testing stopping time and how many faults be residues in software the (the maximum value of data) during these software testing process, therefore we assume the maximum value and the training result can be inaccuracy. In this paper, we present neural network approach for software reliability prediction with unnormalized (actual or original collected) data. This approach is not consider the maximum value of data and possible use the network without normalizing but the predictive accuracy is better. Also, the unnormalized method shows better predictive accuracy than the normalized method given by maximum value. Therefore, we can make the best use of this model in software reliability prediction using unnormalized data.

• 기술사
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• 제39권1호
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• pp.70-73
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• 2006

New human sense of value in Knowledge Society of 21th Century is reestablished by that it demanded new thinking for changed today's stage. Reestablishment of new human sense of value is considered by tradition and custom, and now then today's social standard due to focus. Productive human sense of value do to recreate for all round human relations and fertility human life demand it. Korea National Statistical Office(http://www.nso.go.kr-Dec 20. 2005) was officially announced it. that Korean Life Table(2003) presented the reminder of human life and roughly equation model of 'the reminder of human life' is 'Korean average longevity of human life-Present Korean age=About the reminder of human life' on the basic 2003 year. And then we will live a life worth living for our remaining day

• 한국경영과학회지
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• 제27권2호
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• pp.63-79
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• 2002

During the last decade many enterprises spent a huge amount of money for investment on Information Technology (IT) & Information System (IS) to attain competitive advantage and to maximize their business performance by satisfying the various requirements of customers. Under such circumstances, methodologies for evaluating IT impact on business performance are very important issues for strategic decision making on investment. In this study, we propose a performance evaluation model that adopts the concept of the Balanced Scorecard (BSC) and the Value Chain to analyze the financial impact and non-financial impact of IT & IS at each critical work area. This model combines the 4 evaluation areas from BSC and 6 critical work areas from Value Chain and measures the Key Performance Indicator (HPI) and the effect of KPI. Also, we present a case study of which the evaluation model has been conducted on a major manufacturing company. finally. we address some important notes to improve the IT & IS performances in the real-world.

• 한국정밀공학회지
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• 제1권1호
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• pp.50-58
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• 1984

In the present paper are calculated and compared the stresses on the normal tools and the restricted tools which have three various rake angles by Least Square Method. The results obtained are summerized as follows. The tool displacement at rake angle .alpha. = 12 .deg. and .alpha. = 0 .deg. is positive value in the principal cutting direction and negative value in the feed direction. At rake angle .alpha. = -12 .deg. the displacement is negative value in both of directions. The principal stress of the restricted and normal tool is maximum at the tip of the tool, the shear stress is maximum after a certain distance from the tip. The result of FEM and P.E method shows that in the range of rapid decreasing of normal stress of the tool edge, the shear stress is maintaining a certain value. This is due to the friction characteristic of the chip.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 춘계학술대회 논문집
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• pp.43-48
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• 2001

Price of Used Vessel is Key-point of Ship trading but it is very troublesome part. Because it is different from the Seller and the Buyer's caculated price, It is appropriated by The Sellers and The Buyers' mutual agreement. In case of the Buyers. it is difficult in calculating price of used ship without entrusting the ship broker, beca- use evaluation method of secondhanded vessel has not formulated and the ship broker has experientially computed Remain Value of used vessel. For this work, structure of ship trading market, trading flow, the factor of price composition and Affecting factor of price is reviewed, and it examined relationship with price. On these base, a computer software integrated database system and object-oriented technique is developed. The developed system is expected helpful to evaluation of remain value of the used vessel.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.126-133
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• 2008

Geotechnical limit state design methods; LRFD of North America is an approach that estimates resistance using design model and then multiplies resistance factor by calculated resistance to reflect the uncertainty of geomaterials and design models; whereas, Eurocode of the Europe employs the partial resistance factor applied directly to each variable in the resistance equation that individual soil properties such as cohesion and angle of internal friction are applied. This discussion paper is a study on characteristic value which has globally been argued through processing of development of Eurocode 7 for geotechnical design even to the present. Estimating the characteristic value of soil properties affects not only determination of design value applied directly to design of geotechnical structures, but also economic feasibility and stability of the structures.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.912-920
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• 2006

The purpose of this study is to present the design standard for load density in subway station. From the data of electric equipment capacity and electric power consumption for 43 subway stations, current levels of the load density and excess capacity factor were surveyed and analyzed, In addition mean value, standard deviation, maximum value, median value and correlation coefficient were evaluated through excel program. Also it was carried out the regression analysis. The estimation method of load density and design criterion were studied. As a result, load density in this thesis have been proposed : 51.3 $[VA/m^2]$ on the general power load can be a standard value for subway station.