• Environmental and Resource Economics Review
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• v.20 no.1
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• pp.119-153
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• 2011

This study reviews various aspects of model formulating processes of dichotomous choice responses of the contingent valuation method (CVM), which has been increasingly used in the preliminary feasibility test of Korea public investment projects. The theoretical review emphasizes the consistency between WTP estimation process and WTP measurement process. The empirical analysis suggests that two common parametric models for dichotmous choice responses (RUM and RWTP) and two commonly used probability distributions of random components (probit and logit) resulted in all most the same empirical WTP distributions, as long as the WTP functions are specified to be a linear function of the bid amounts. However, the efficiency gain of DB response compared to SB response were supported on the ground that the two CV responses are derived from the same WTP distribution. Moreover for the exponential WTP function which guarantees the non-negative WTP measures, sample mean WTP were quite different from median WTP if the scale parameter of WTP function turned out to be large.

• Environmental and Resource Economics Review
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• v.24 no.2
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• pp.435-461
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• 2015

Recently, Korean development Institute includes water for environmental improvement as an additional water demand category in water resources development project. In response to this change, this paper is to measure benefits of providing additional water in Yeondok Ohsip River by applying contingent valuation method. This study extended the conventional CVM design by incorporating distance variable into WTP function of dichotonomous choice responses and treated protest bids by estimating sample-selection models. The empirical analysis exhibited that more than 30% of respondents were categorized as protest bids and the mean of WTP from sample selection models were three times higher than that of the whole sample. In addition, the distance variable had significantly negative impact on sample WTP regardless of variables forms, and the geographical market area were more 400km, which implies that beneficiaries of water service would the households from the whole nation.

• Journal of Korean Society of Forest Science
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• v.79 no.3
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• pp.231-244
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• 1990

As the complexity of society increases, the demand for the forest-based recreational site is also increased. This, in turn. makes congestion an ubiquitous type of externality in forest-based recreational site. Efficient resource allocation requires this congestion effect to be accounted and considered in the decision making process. In this content, this study was conducted to suggest a process which can be used to measure the congestion and determine the optimal number of users. Willigness to pay(WTP) function obtained from Book Han San National Park users suggested that every 20.000 users increased decrease the satisfaction of users obtained from the site visit be 27.3%. For the purpose of demonstration this WTP function is applied tit determine the optimal number of users which is estimated as about 73,000 persons per day.

• Journal of KIISE:Information Networking
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• v.28 no.3
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• pp.297-308
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• 2001

In this paper, we design, validate and implement WTP(Wireless Transaction Protocol) using SDT(SDL Design Tool). We do modeling WTP protocol by SDL(Specification and Description Language), design and implement the environment function for the interface between the SDL system and the UDP platform and design APIs(Application Programming Interface). And we do conformance testing for WTP protocol software using ITEX(Interactive TTCN Editor and eXecutor). We write ATS(Abstract Test Suite) by TTCN(Tree and Tabular Combined Notation) and make ETS(Executable Test Suite) by the TTCN compiler supplied by ITEX.

• Journal of Advanced Navigation Technology
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• v.6 no.1
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• pp.69-76
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• 2002

With the growth of data communication service by mobile devices, WAP is proposed to efficiently access the Internet contents by user request through wireless condition that has a high error rate and mobility. But, because a transmission speed of WAP is limited, it takes many times to transmit and to receive the data. This paper has studied the WAP packet transmission time using WTP-SAR algorithm. As a method that is to improve transfer capability of WAP, using SAR function in WTP, total message down from upper layer has been fragmented and packet is transmitted through RLP frame time slot. Then, we have analyzed the transmission time of WAP packet with variable RLP layer size on the wireless CDMA network for next generation systems. From the results, we could obtain the WAP packet transmission time and optimal WTP packet size.

• Environmental and Resource Economics Review
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• v.25 no.1
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• pp.1-25
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• 2016

This study investigated the variability of WTP estimates(i.e. mean or median) with ad hoc assumptions of specific parametric probability distributions(i.e. normal, logistic, lognormal, and exponential distribution) to estimate WTP function using dichotomous choice CV data on mortality risk reduction. From the perspective of policy decision, the variability of these WTP estimates are intolerable in comparison with those of Turnbull nonparametric estimation method which is free from ad hoc distribution assumptions. The Turnbull nonparametric estimation can avoid a kind of misspecification bias due to ad hoc assumption of specific parametric distributions. Furthermore, the WTP estimates by Turnbull nonparametric estimation are robust because the similar estimates are elicited from a dichotomous choice or double dichotomous choice CV data, and the statistically significant WTP estimates can be obtained even though it is not possible by parametric estimation methods. If there are considerable variability among those WTP estimates by parametric estimation methods in condition with no criteria of model adequacy, the mean WTPs from Turnbull nonparametric estimation can be the robust estimates without ad hoc assumptions, which can avoid controversial issues in the perspective of policy decisions.

• Environmental and Resource Economics Review
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• v.20 no.3
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• pp.595-628
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• 2011

This study investigates the issues and suggests reform measures in applying CV methods to the Korea Development Institute's (KDI's) Preliminary Feasibility Test (PFT) of public projects. Most public projects on culture, science and environment evaluated under the PFT system belong to the category of "nonstandard" projects whose outputs are non-marketed, and CV is currently the main tool used for their benefit estimation. A careful discussion and investigation is recommended for the selection of target population, payment vehicle, and number of payment times. Operating expert reviews, focus group interviews, and pre-tests is highly recommended to reduce the potential bias involved in the CV studies. A single or double bounded dichotomous choice format is the most popular design of questionnaire, but we identify several undissolved issues in designing and implementing the format. Some other forms of inducing WTPs may still deserve our consideration. Various specifications of the WTP function need to be tried and tested based on their stability, in particular. Employing a nonparametric approach is also recommended. Treatments of 0 or negative WTPs and protest bids are shown to be the most serious issues that affect the estimation results significantly. We review diverse measures of handling those issues and summarize their advantages and shortcomings.

• Journal of Korea Water Resources Association
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• v.56 no.3
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• pp.225-233
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• 2023

Urban rivers and their surrounding environments have been altered due to factors such as rapid economic growth and urban development. This alteration have caused the rivers to lose their original value and become exposed to various pollution, resulting decrease in citizens' quality of life. This study aims to estimate citizens' Willingness To Pay (WTP) for water quality improvement in Suyeong River in Busan. To estimate the non-market value of the Suyeong River, the WTP of Busan citizens for water quality improvement was estimated, applying Contingent Valuation Method (CVM). The WTP for improving the water quality from Grade 4(polluted water) to Grade 2(game fish like bass can live in it) was estimated using the water quality ladder concept of the US Environmental Protection Agency, assuming annual donations for five years. For the CVM, the logistic distribution and Spike Model were adopted. As a result, citizens residing in the surrounding area of Suyeong River expressed a higher WTP. Considering more than half of the Busan citizens are aware of the "conservation of nature and ecosystems" as a major function of the Suyeong River, this higher WTP could serve as a basis for improving the value of urban rivers.

• Environmental and Resource Economics Review
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• v.15 no.5
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• pp.921-937
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• 2006

In this paper, we apply fuzzy theory in a discrete choice Contingent Valuation Method(CVM) in order for dealing preference uncertainty problem. Fuzzy membership function is used in an empirical analysis to estimate the willingness-to-pay(WTP) for the preservation of the endangered Asiatic Black Bear in Korea. The estimated WTP was about 9,090 Korea Won per household with 78 percent of confidence level. The advantage of applying fuzzy theory in the valuation method could be found in its ability to measure the confidence level of the estimated WTP.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.1
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• pp.39-46
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• 2009

A method to improve water treatment efficiency by coagulant overdosing for high pH raw water at a drinking water treatment plant (WTP) which had no pH adjusting facilities was investigated. Poly aluminum chloride (PACl) was used for coagulant, and turbidity removal efficiency was evaluated as a function of PACl dosage increases. pH and turbidity of supernatant of jar-tester were 7.10 and 0.50 NTU respectively, when the turbidity, pH, alkalinity, water temperature, conductivity of raw water were 1.75 NTU, 9.38, 46.5 mg/L, $6.4^{\circ}C$, $400{\mu}s/cm$, respectively. Turbidity of settled water was reduced from 2.18 NTU to 0.28 NTU (87% reduction) when PACl dosage was increased from 16 mg/L to 45 mg/L at a full scale WTP. This can be attributed to the recovery of coagulant efficiency by pH reduction with the increase of coagulant dose, however coagulation efficiency was reduced with the formation of Al(OH)4- by PACl addition at higher pH. Coagulant overdosing was proven to be a rapid and effective method for high pH raw water, which can be applied at drinking WTP.