• Journal of the Korea Institute of Building Construction
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• v.12 no.1
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• pp.108-114
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• 2012

Escalation method examining the changes in price index has been widely utilized in public construction projects. The previous escalation method determined estimated changes in price based on the average unit price of contract items over a period of time. In relation to this method, the issue has been raised that the fluctuation rates of previous method show different trends compared with other related price indices, as the influence of the small group of contract items with large unit prices overwhelms the others. This research suggested an improved escalation method which estimates the fluctuation rate by examining the changes in CCI (construction cost index) and applies it to the total amount or the partial amount deducted for labor cost in price escalation for previous bid price method. To verify the improvement, a case study is conducted on an educational facility, and the fluctuation rate was estimated in two different base periods (short term, long term). The results over the long term showed similar tendencies to those of related price indices, as well as significant differences in fluctuation rates compared to those of the previous method.

• KIEE International Transactions on Power Engineering
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• v.5A no.4
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• pp.311-321
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• 2005

A competitive generating company (GENCO) could maximize its payoff by optimizing its generation assets. This paper considers the GENCO's arbitrage problem using price-based unit commitment (PBUC). The GENCO could consider arbitrage opportunities in purchases from qualifying facilities (QFs) as well as simultaneous trades with spots markets for energy, ancillary services, emission, and fuel. Given forecasted hourly market prices for each market, the GENCO's generating asset arbitrage problem is formulated as a mixed integer program (MIP) and solved by a branch-and-cut algorithm. A GENCO with 54 thermal and 12 combined-cycle units is considered for analyzing the proposed formulation. The proposed case studies illustrate the significance of simultaneous arbitrage by applying PBUC to multi-commodity markets.

• Journal of information and communication convergence engineering
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• v.18 no.3
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• pp.167-175
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• 2020

The net income per unit area from crop production could be the most critical consideration for agricultural producers during cultivation planning. This paper proposes a scheme for predicting the net income per unit area based on machine learning and related calculations. This scheme predicts rice production and operation costs by applying climate and price index data. The rice price is also predicted by applying rice production and operation cost data. Finally, these predicted results are employed to calculate the predicted net income, which is compared with the actual net income. Consequently, the proposed scheme shows a meaningful degree of conformity, which indicates the potential of machine learning for predicting various aspects of agricultural production.

• Journal of the Korea Institute of Building Construction
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• v.5 no.2 s.16
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• pp.147-152
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• 2005

The purpose of this study is to present a rational approach for estimating the unit price and the amounts of sealing materials of the sealing works. This approach, considering field conditions and sealing materials' characteristics, can optimize the cost of the sealing works as well as that of maintenance. For the study, 10 case buildings for 3 years, built by middle size construction firm, were studied in order to investigate the unit price and the amounts of sealing materials.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.9
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• pp.550-556
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• 2003

Price-based unit commitment is one of bidding strategies which a Genco may take in a practical manner. For that purpose, it is required for a Genco to decide output levels of its generators at each trade period. In this paper, an economic dispatch of thermal units is proposed considering the quantity of reserve contracts. A gradient projection algorithm is adopted as an optimization tool. A direct form of a projection matrix without any calculation of matrix inverse and multiplications is induced. Besides, it is proved that there is no need to check one of the two optimality conditions in the gradient projection method, which also requires matrix inverse and multiplications.

• Proceedings of the Korea Contents Association Conference
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• 2019.05a
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• pp.211-212
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• 2019

The objectives of this research are to test the utility of semiparametric geographically weighted regression (SGWR, a spatial analysis method) in the small-scale urban sample, and to understand the geographic patterns of provision and pricing of sharing economy based accommodations in the tourist city. This paper focused on how network distance to heritage site, to casino, residential unit prices and other five attribute categories determine Airbnb price in Macau SAR, China. Findings show that SGWR models outperformed OLS models. Moreover, comparing with heritage sites, casinos are the stronger factors to drive up Airbnb (including hostels) rooms' provision and their prices; and residential unit prices are not related with the Airbnb price in the attraction clusters in Macau. This research showed a little example for the applications of SGWR in the small city, and for the analysis of online marketplace data as new urban study material. Practically, this study provides some scientific evidence for hosts, guests, urban planners, and policymakers' decision making in Macau.

• The Journal of Fisheries Business Administration
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• v.49 no.2
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• pp.21-35
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• 2018

Squid is a popular seafood in Korea. However, since the 2000s, the squid production has been declining. The unstable supply of the squid products may cause price fluctuations of fresh and chilled squid. These price fluctuations may be relatively more severe than them of other commodities, because the fresh and chilled squid can not be stored for a long period of time. Thus, this study analyzes the structural characteristics of price volatility and price asymmetry of fresh squid based on off-diagonal GARCH model. Data used to analysis of this study are daily wholesale and retail prices of fresh squid from January 1, 2006 to December 31, 2016 provided in the KAMIS. As theoretical approaches of this study, first of all, the stability of the time series is confirmed by the unit root test. Secondly, the causality between distribution channels is checked by the Granger causality test. Thirdly, the VAR model and the off-diagonal GARCH model are adopted to estimate asymmetry effect and price volatility spillover between distribution channels. Finally, the stability of the model is confirmed by multivariate Q-statistic and ARCH-LM test. In conclusion, fresh squid is found to have shock and volatility spillover between wholesale and retail prices as well as its own price. Also, volatility asymmetry effect is shown in own wholesale or retail price of fresh squid. Finally, this study shows that the decrease in the fresh squid retail price of t-1 period than the increase in the t-1 period has a greater impact on the volatility of the fresh squid wholesale price in t period.

• Health Policy and Management
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• v.13 no.4
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• pp.84-98
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• 2003

This research objective is to determine the optimal price break points for n­block tariff, because comparing non­linear pricing with uniform pricing on the basis of profit, n­block tariff outperforms two­part tariff, all unit discount price schedule, and uniform pricing. Although the merits of non­linear pricing are well documented, the attempt to practice the non-linear pricing in medical service sector has been relatively rare. The determination of the parameters under n­block tariff is the interesting decision making agenda for marketers. Under n­block tariff, the marketers should decide the optimal price break points and the optimal marginal price for each price zone. The results can be summarized as follows: The researchers found that mixture model can be the feasible methodology for determining the optimal number of n­block tariff and identifying the optimal segmentation criteria. We demonstrate the feasibility and the superiority of the mixture model by applying it to the database of medical examination. The results appear that the number of patients per month can be the optimal segmentation variable. And 6­block tariff is the optimal price break for this medical service.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.5
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• pp.579-586
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• 2005

Recently, it has demanded to the wireless monitoring system in stand-alone PV power generation system. We propose the multiplex monitoring method using RF unit of low-price. RF unit consists of RF modem and communication controller. It is also able to use by repeater to communicate long distance. In this paper. two algorithms were programmed by CCS-C and C++ for multiplex monitoring method, The algorithm of choosing unit was used 'select and poll method' and the course assignment algorithm was embodied with 'Bellman-Ford algorithm'. The good result was achieved in the actual test without communication-data lose. The proposed method will be applied such as monitoring system of PV light on the wayside, monitoring system of unmanned lighthouse, monitoring system of refrigeration container on vessel and so on. It can be applied in the field that various ocean energy system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.4D
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• pp.357-366
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• 2012

Construction equipment has applied to depreciation over the years, however, the price index for construction equipment is not properly reflected in existing quantity per unit and the local tax law. Thus, this study shows the analysis of the corporate tax law, the local tax law and business accounting standards, characteristics of the domestic depreciation system and depreciation methods, and the capital recovery factor of construction equipment applying the theory for economic efficiency. It also presents cases of depreciation on the basis of quantity per unit and tax law using straight-line depreciation method and declining balance method. It is proposed that the relations of the application system of permissible period for construction equipment and the existing system be explained and the application system of permissible period for construction equipment be imposed. Furthermore, it proposes the development of depreciation tables of construction equipment monthly expenses based on the domestic price index and applications. In addition of that, it proposes the analysis of pros and cons of the methods suggested and application limits of the study and subsequent improvement plans. This study should reflect more rational and objective reality in quantity per unit and tax law.