• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.3 s.59
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• pp.63-73
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• 2006

Auctions have been traditionally used to find the current price of goods when little is known about their true value. A special auction methodology, called a 'simultaneous multiple round auction', is available to auction radiofrequency spectrum where all lots are simultaneously on of for over multiple rounds of bidding. This type of auction is especially useful when there are lots that are of essentially equal value and substitutable, except that different bidders may prefer different combinations of lots. By using multiple rounds, a bidder has the opportunity to gather information concerning the value of individual lots and can change strategy by shifting the bidding to another preferred combination if one combination becomes too expensive. Information is released in three main ways during an auction: Bidder Status; High Bids; and Bandwidth Value.

• Applied Chemistry for Engineering
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• v.29 no.3
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• pp.270-277
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• 2018

The adsorption of Eosin Y by the activated carbon (WCAC) prepared from waste citrus peel was investigated by using response surface methodology (RSM) and Box-Behnken design (BBD) statistical procedures. Experiments were carried out as per BBD with three input parameters, the Eosin Y concentration (Conc. : 30~50 mg/L), the solution temperature (Temp. : 293~313 K), and the adsorbent dose (Dose : 0.05~0.15 g/L). Regression analysis showed a good fit of the experimental data to the second-order polynomial model with coefficients of the determination ($R^2$) value of 0.9851 and P-value (Lack of fit) of 0.342. An optimum dye uptake of 59.3 mg/g was achieved at the dye concentration of 50 mg/L, the temperature of 333 K, and the adsorbent dose of 0.1056 g. The adsorption process of Eosin Y by WCAC can be well described by the pseudo second order kinetic model. The experimental data followed the Langmuir isotherm model.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.137-144
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• 2007

In the year of 1980 and 2000, the Korean government institutionalized the Value Engineering methodology in the construction phase and the design phase respectively. While design-phase VE have been applied to construction industry actively, which was institutionalized 7 years ago, construction-phase VE have not been applied to industry frequently, although it was institutionalized 25 years ago. On the other hand, at the time of social demands for VE is increasing, it has been pointed out that VE should be compatible with the delivery system. And the time of VE study, the operational management of VE study, and the maintenance process of the result of the VE study also should be considered. In this study, a scheme to improve VE methodology in the construction industry is proposed based on the literature review and the data analysis of domestic and foreign state of VE.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.6
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• pp.128-135
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• 1996

This paper proposes a high precision measurement technique to obtain the height of gage block with a few millimeter height. The proposed technique is consisted of two steps : In the first step, laser position transducer and electric micrometer are adopted to obtain a coarse value of the height of gage block, and then, in the second step, heterodyne laser interferometry is adopted to acquire the precision value. A new kind of phase detector is constructed in the low cost for the heterodyne interferometer and its linearity with ${\pm}1%$ is confirmed by experiment. Also measurement error factors due to enviroments are discussed and methodology to reduce such errors is proposed. Preliminary experiments are carried out for the gage blocks of as high as a few millimeter.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.04a
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• pp.31-38
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• 1998

In this study, statistical analyses implemented in the EPRI EQHAZARD programs were employed to estimate the sismicity parameters in the Korean peninsula based upon an combined Korean earthquake catalog. The combined earthquake catalog was prepared by performing earthquake clustering analysis on the collected earthquake catalogs provided by experts of the seismic panel during the PSA for Yonggwang Units 1 & 2. The duplicate earthquake events and secondary events in earthquake clusters have been successfully screened. The resultant earthquake catalog was analyzed to quantitatively assess the incompleteness of the earthquake catalog for specified earthquake magnitudes and time periods. The result shows that the earthquake catalog of the Korean peninsula is complete for the times periods of 1392 ~ 1750 and 1905 ~ 1989 (AD) and earthquake magnitude above 4.5. The PSHA methodology of EQHAZARD features the estimation of inhomogeneous a-and b-values within a seismic source. This study shows various results of a-and b-value is well constrained lying between o.6 and 1.0. Also the confidence of estimated a-and b-value for a specifed location was assessed by quantifing the uncertainty of these parameters using bootstrap simulation.

• Journal of the Korean Society of Safety
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• v.25 no.3
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• pp.112-117
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• 2010

This study presents a methodology to evaluate the driving safety of vehicles against localized high wind on the roads over the valleys or along the coasts. Risk level for vehicle accident is derived from the side slip caused by cross wind, and then safety criteria based on reliability for driving stability are defined. The level of safety is classified according to probability of exceeding against wind speed using the concept of extreme value statistics. To attain the safety level of vehicle on bridges, numerical simulations using Computational Fluid Dynamics(CFD) are performed. Based on this result, risk reduction and quality improvement is expected through analysis for each alternative in bridges design, construction and operation & maintenance stage with proposed process

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.4
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• pp.287-293
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• 2003

This study examined the temperature-dependent regression model of energy consumption based on various measuring period. The methodology employed was to construct temperature-dependent linear regression model of daily energy consumption from one day to three months data-sets and to compare the annual heating energy consumption predicted by these models with actual annual heating energy consumption. Heating energy consumption from a building in Daejon was examined experimentally. From the results, predicted value based on one day experimental data can have error over 100%. But predicted value based on one week experimental data showed error over 30%. And predicted value based on over three months experimental data provides accurate prediction within 6% but it will be required very expensive.

• Korean Journal of Construction Engineering and Management
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• v.8 no.3
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• pp.159-167
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• 2007

In this study, the concepts of integrated VE analysis assessment is introduced in order to achieve "Design for Deterioration performance" in design VE phase. For this purpose, a framework for fuzzy reliability based LCC and value analysis model using fuzzy logic based approach for breakwaters Projects is suggested. It is anticipated that the methodology Proposed in this paper can also be utilized in the design and maintenance phase of other facilities where decision making is made for the fuzzy reliability based life cycle cost and value analysis.

• IE interfaces
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• v.25 no.2
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• pp.204-215
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• 2012

Recently, more and more firms are considering the adoption of RFID technology because it is expected to make process automation easier and has many different application areas. A review of existing studies about RFID adoption methodology shows that the most of the proposed methodologies are mainly based on economic evaluations. However, in the near future when the adoption and diffusion of RFID become major forces among business firms, it would surely have some limits to decide its adoption solely on the basis of economic considerations. In order for all the important strategic objectives to be considered during the major decision processes, it is necessary to make explicit what the decision makers really want to achieve from the RFID system. In this paper, we propose a general value model of RFID system which can provide an overall vision of all values RFID adoption may offer and a way to search and evaluate alternatives on the basis of these values. Especially, this model contains not only opportunities but also risks of RFID adoption so that a balanced consideration can be made. The model building process was essentially based on the 'value-focused thinking' approach proposed by R. Keeney. The proposed model is expected to provide insights about what to do in the process of introduction in order to maximize the potential benefits and minimize the negative risks. Referring to this value model, the important decisions would have greater chance to be based on a balanced consideration of opportunities and risks.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2008.04a
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• pp.306-310
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• 2008

Fuzzy regression, a nonparametric method, can be quite useful in estimating the relationships among variables where the available data are very limited and imprecise. It can also serve as a sound methodology that can be applied to a variety of management and engineering problems where variables are interacting in an uncertain, qualitative, and fuzzy way. A close examination of the fuzzy regression algorithm reveals that the resulting possibility distribution of fuzzy parameters, which makes this technique attractive in a fuzzy environment, is dependent upon an h parameter value. The h value, which is between 0 and 1, is referred to as the degree of fit of the estimated fuzzy linear model to the given data, and is subjectively selected by a decision maker (DM) as an input to the model. The selection of a proper value of h is important in fuzzy regression, because it determines the range of the posibility ditributions of the fuzzy parameters. In this paper, we discuss the interdependent relationship among the h value, membership function shape, and the spreads of fuzzy parameters in fuzzy linear regression with fuzzy input-output using shape-preserving operations.