• Journal of the Institute of Convergence Signal Processing
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• v.2 no.3
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• pp.86-92
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• 2001

Position controls are very important in semiconductor manufacturing devices, machine tools, precision measuring instruments, etc. to measure the distance of movement of moving objects in minute units and the accuracy of measurement for the moving distance in these devices affect the performance of the whole devices. Therefore, in those precision instruments, a sensing device that can measure the distance of movement with high-precision resolution is required. Thus an optical encoder that has such advantages as easy digital interface, economical price, and a resolution similar to that of laser interferometers can be used. In this paper, a interferometer-type linear scale with easy digital interface and high-resolution has been set up and measured the distance of movement based on the diffraction principle. Interference signals produced in this optical setup of the linear scale have beers digitalized through fabricated photodetectors and designed signal processing circuits. A resolution of 0.5${\mu}{\textrm}{m}$ is acquired from the experimental interferometer-type linear scale without for the movement of scales any additional dividing circuits. It is shown that from this experiment a high-resolution distance measurement device can be designed by a simple optical setup.

• Korean Journal of Agricultural Science
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• v.39 no.1
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• pp.151-159
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• 2012

This paper analyzes the consumers' preference for packaged apple and derives the measures to vitalize the distribution of packaged apple. To do this, survey was conducted for consumers in large cities, Seoul, Busan, and Daegu to observe their purchasing behavior and satisfaction both for packaged and unpackaged apple. Survey was focused to how they are satisfied with several attributes of package such as size, appearance, content, material, and label. On the basis of the survey results, the values of the package attributes were estimated. Survey results show that consumers tend to buy unpackaged apple rather than packaged apple. About 34 percent out of 313 respondents have ever purchased apple packed with paper box while only 10.5 percent have an experience to buy packaged apple with transparent box. Most respondents answered they preferred the package of five to six apples and 1.3 kilograms most. They preferred mid or large size apple. Estimation of the values of the package attributes using the conjoint analysis shows that consumers are giving the highest value to the price of packing material. It means that consumers are reluctant to the extra payment resulted from packing the apple. Therefore, the efforts to reduce the cost of packing apple should be made steadily. In order to vitalize the distribution of small packaged apple, the package should contain high quality apple with high sugar content, proper size, good appearance, and so on. And it needs to be promoted to the consumers that small packaged apple are not inferior to apple packed with paper box.

• The Korean Journal of Applied Statistics
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• v.27 no.1
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• pp.123-132
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• 2014

Inflation uncertainty is known to have deleterious effects on facilities investment by disturbing the corporate decision on the opportunity cost of investment. In this paper, we test the validity of this hypothesis in Korea by estimating the inflation uncertainty with both a time-varing parameter model with GARCH disturbances and the relative price volatility and then, estimate the facilities investment equation which includes those uncertainty indicators. The uncertainty indexes estimated by the above-mentioned methods continue to fluctuate even after the inflation rate has dropped dramatically reflecting the structural changes of Korea's economy since the financial crisis in 1997. As a result of estimation of the investment equation by both OLS and GMM, we find the inflation uncertainty has a negative effect on facilities investment with a statistical significance. Moreover, by means of Markov-switching regression model utilized to verify the non-linearity of this relationship, we draw a conclusion that this negative effect of inflation uncertainty heightens asymmetrically during the downturn periods of business cycle.

• Journal of Internet Computing and Services
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• v.13 no.2
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• pp.1-11
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• 2012

The purpose of this paper is to estimate 'willingness to pay' for mobile data service by using contingent valuation method with double bounded dichotomous choice question. The findings are as follows.: First, the willingness to pay of mobile data service is considerably lower than current retail price. Second, the perceived degree of mobile data service such as awareness and benefit recognition is positively related to the willingness to pay of mobile data service. Our results suggest that active promotion and strengthening of the content of mobile data service are needed in order to enhance the profitability of mobile operators. The analysis results will be used to set the mobile operator's pricing strategy and to build up a successful communication policies in the mobile ecosystem.

• Journal of the Korean Association of Geographic Information Studies
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• v.4 no.4
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• pp.29-38
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• 2001

This study addresses the topic of suitability analysis for helping with land use planning, which is one of important decision-making in urban planning, utilizing geographic information system. Covering the Kumi City before integrating with neighbor county, the site suitabilities for land uses, which are categorized into residential, commercial, industrial and green, were analyzed using the overlay method based upon the database constructed for this study. In the process, assessment criteria which include environmental factors and relative weights were determined and also the land use/cover map and NDVI map which were generated through satellite image processing were included in the database. The suitability maps by four function spaces were derived according to the grade and compared with the present land use state and the land use concept map of urban master plan. For more accurate analysis, practical developing plan, land price data, soil data should be included. Also if the demand estimation data by each land use had been added, the reliability of location allocation could have been raised.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.409-414
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• 2008

The purpose of this study is to analyze the problem of BTL business through the sensitivity analysis of financial model and presented efficiency business strategy when private business owner propose their business. For this, we analyzed the sensitivity of financial model after analyzed costs of the school facility construction case for each place of business. The results of this study are as follows. 1)As the results of the sensitivity of financial model, requirement-earning rate for the results of analysis was decreased average 2.28 points (0.5%) per increasing 0.10% and Construction costs and the maintenance costs were decreased average 10.73 points (2.38%), 6.22 points(1.38%) for increasing 1billion won. 2) The Problem of BTL business according to the sensitivity analysis of financial model was analyzed that the price consultation low investments, and estimation from personal consideration caused it. So, it was analyzed to increase maintenance costs is more efficient method than to increase construction costs.

• The Korean Journal of Applied Statistics
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• v.28 no.3
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• pp.393-406
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• 2015

We examine how to model mortality risk using the adaptation of the mean-reverting processes for the two factor model proposed by Cairns et al. (2006b). Mortality improvements have been recently observed in some countries such as United Kingdom; therefore, we assume long-run mortality converges towards a trend at some unknown time and the mean-reverting processes could therefore be an appropriate stochastic model. We estimate the parameters of the two-factor model incorporated with mean-reverting processes by a Metropolis-Hastings algorithm to fit United Kingdom mortality data from 1991 to 2015. We forecast the evolution of the mortality from 2014 to 2040 based on the estimation results in order to evaluate the issue price of a longevity bond of 25 years maturity. As an application, we propose a method to quantify the speed of mortality improvement by the average mean reverting times of the processes.

• Land and Housing Review
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• v.6 no.3
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• pp.107-115
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• 2015

Recently one of interest concern in domestic housing market is to reduce the difference of supply and demand. Exact demand estimation by accurate demand region is a essential cue to reduce the gap. This empirical study compared the data of housing subscriber's real address with estimated demand area on household movement, which are applied by advanced studies. This empirical case data is related to 3 housing development districts in metropolitan area. As a result, This study found that the real demand area has a more widened coverage compared with those of household movement one. For to establish exact demand area, we found, more complementary considerations should be taken. Especially some factors such as distance between a project site and downtown of Seoul Metropolitan City, locational competitiveness on main demand and behind demand, and development scale are more considerable variables. In additionally, we found the demand areas are influenced by housing rental types, sizes and the real estate business trends. And also, this study found those factors should be considered with housing price and locational competitiveness.

• Journal of Cadastre & Land InformatiX
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• v.46 no.2
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• pp.43-55
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• 2016

This study estimated land prices using instance-based learning. A k-nearest neighbor method was utilized among various instance-based learning methods, and the 10 distance metrics including Euclidean distance were calculated in k-nearest neighbor estimation. One distance metric prediction which shows the best predictive performance would be normally chosen as final estimate out of 10 distance metric predictions. In contrast to this practice, an ensemble technique which combines multiple predictions to obtain better performance was applied in this study. We applied the gradient boosting algorithm, a sort of residual-fitting model to our data in ensemble combining. Sales price data of farm lands in Haenam-gun, Jeolla Province were used to demonstrate advantages of instance-based learning as well as an ensemble technique. The result showed that the ensemble prediction was more accurate than previous 10 distance metric predictions.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.359-362
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• 2002

The construction industry from the research about materials calculate automation became accomplished plentifully. Material price calculate with application in the CAD plan is more quicker and accurate than with existing handy work. It gives a many effect in development of the research and estimation program against material calculate production automation with application of the CAD. But material calculate production uses an estimate program from generally a framework construction and the material calculate production work becomes accomplished. A thesis of the material calculate production methodology about a part of materials boundary condition from material calculate production work of framework construction is the actual condition which is insufficient. From the dissertation which it sees standardize the concrete, a concrete form a each part of materials calculate method from framework construction material calculate production. It standardize a part of materials agree with a condition of material calculate methodology which from a each part of materials boundary condition.