• Proceedings of the Korean Association for Survey Research Conference
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• 2001.04a
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• pp.83-107
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• 2001

The contingent valuation method used survey questions to elicit people's preferences for public goods by finding out what they would be willing to pay for specified improvement in them. The method is thus aimed at eliciting their willingness to pay in money amounts. It circumvents the absence of markets for public goods by presenting consumers with hypothetical markets in which they have the opportunities to buy the good in question. The hypothetical markets may be modeled after either a private goods market or a political market. Respondents are presented with material, often in the course of a personal interview conducted face to face. An on-site survey was conducted to 1107 randomly selected P-mountain users using a dichotomous choice questionnaire for the contingent valuation method. Seventeen different bid sets were chosen ranging from the lowest bid of 300won to the highest bid of 2,100won to elicit a reasonable entrance fee in the suggested bid had been determined, and the expected value of willingness to pay was estimated using binary-logit model. The average public value of P-mountain per individual user was estimated to be 1,055.92won∼1,995.61won according to the binary-logit model. The economic value of this P-mountain which includes both use value and existence value can be determined by aggregating the average value giving total willingness to pay for the entire population, in this case 5.491 billion ∼ 10.377 billion.

• Survey Research
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• v.2 no.2
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• pp.83-107
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• 2001

The contingent valuation method uses survey questions to elicit people's preferences for public goods by finding out what they would be willing to pay for specified improvement in them. The method is thus aimed at eliciting their willingness to pay in money amounts. It circumvents the absence of markets for public goods by presenting consumers with hypothetical markets in which they have the opportunities to buy the good In question. The hypothetical markets may be modeled after either a private goods market or a political market. Respondents are presented with material, often in the course of a personal interview conducted face to face. An on-site survey was conducted to 1107 randomly selected P-mountain users using a dichotomous choice questionnaire for the contingent valuation method. Seventeen different bid sets were chosen ranging from the lowest bid of 300won to the highest bid of 2, 100won to elicit a reasonable entrance fee in the hypothetical market. The probability of an individual user's willingness to pay for the suggested bid had been determined, and the expected value of willingness to pay was estimated using binary-1ogit model. The average public value of P-mountain per individual user was estimated to be 1,055.92won ~ 1,995.61won according to the binary-logit model. The economic value of this P-mountain which includes both use value and existence value can be determined by aggregating the average value giving total willingness to pay for the entire population, in this case 5.491 billion ~ 10.377 billion.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.1
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• pp.85-92
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• 2017

Recently, electric propulsion systems are used for unmanned surface vehicle, fish finder boat, etc. Some of these propulsion systems can be constructed of two electric motors and propellers for advanced impellent force. In this case, the speed difference generated between two propellers, namely, the synchronous error has a bad influence on the energy efficiency and course error. In this study, a synchronous control system is designed to restrain synchronous error caused by disturbance and mismatched dynamic characteristics. The control system is composed of the reference model, pre-filters, speed controllers, and synchronous controllers. The reference model is used for calculating the decoupled synchronous error and control input for each propulsion system. The pre-filters and speed controllers are designed in order that the propulsion system may follow the reference signal without overshoot and input saturation. And the synchronous controllers are designed from the viewpoint of stable and quick synchronization through root locus mothed approach. Finally, the simulation results show that the designed control system is effective for the disturbance.

• Korean Journal of Clinical Pharmacy
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• v.16 no.1
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• pp.63-68
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• 2006

Gabapentin, 1-(aminomethyl-1-cyclohexyl)acetic acid, is anew antiepileptic drug related to ${\gamma}-aminobutyric$ acid(GABA) currently being introduced in therapy worldwide. The bioavailability and pharmacokinetics of gabapentin capsules were examined in 22 volunteers who received a single oral dose in the fasting state by randomized balanced $2{\times}2$ crossover design. After dosing, blood samples were collected for a period of 24 hours and analyzed by liquid chromatography-tandem mass spectrometry (LC/MS/MS). Time course of plasma gabapentin concentration was analyzed with non-compartmental and compartmental approaches. $WinNonlin^{(R)}$, the kinetic computer program, was used for compartmental analysis. One compartment model with first-order input, first-order output with no lag time and weighting by $1/(predieted\;y)^2$ was chosen as the most appropriate pharmacokinetic model for the volunteers. The major pharmacokinetic parameters $(AUC_{0-24hr},\;AUC_{inf},\;C_{max}\;and\;T_{max})$ and other parameters $(K_a,\;K_{el},\;V_d/F\;and\;Cl/F)$ of $Gapentin^{TM}$ (test drug) and $Neurontin^{TM}$ (reference drug) were estimated by non-compartmental analysis and compartmental analysis. The 90% confidence intervals of mean difference of logarithmic transformed $AUC_{0-24hr}\;and\;C_{max}$ were $log(0.9106){\sim}log(1.l254)\;and\;log(0.8521){\sim}log(1.0505)$, respectively. It shows that the bioavailability of the test drug is equivalent with that of the reference drug. There was no statistically significant difference between the two drugs in all pharmacokinetic parameters.

• Journal of the Korean School Mathematics Society
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• v.19 no.4
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• pp.357-371
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• 2016

The purpose of this study was to decide the task space and Rating Scheme of task difficulty in complicated mathematical modelling situations. One of main objective was also to conform the validation of Rating Scheme to determine the degree of difficulty by comparing the student performance with the statement of the theoretical model. In spring 2014, the experimental setting was in Modelling Course for 38 in-service teachers in mathematics education. In conclusions, we developed the Model of Task Space based on their solution paths in mathematical modelling tasks and Rating Scheme for task difficulty. The Validity of Rating Scheme to determine the degree of task difficulty based on comparing the student performance gave us the meaningful results. Within a modelling task the student performance verifies the degree of difficulty in terms of scoring higher using solution approaches determined as easier and vice versa. Another finding was some relations among three research topics, that is, degree of task difficulty on rating scheme, levels of students performance and numbers of specific heuristic. Those three topics showed the impressive consistence pattern.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.4
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• pp.2105-2110
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• 2016

Purpose: A multicenter, observational, cross-sectional study was conducted to assess factors delaying presentation of breast cancer cases. Materials and Methods: Data were collected from a pair of highly specialized referral centers, both located in the center of the Sudanese capital, Khartoum. For a total of 153 eligible respondents, durations of delay, clinicodemographic factors and reasons of referral were collected from our respondents through self-administered questionnaires. Logistic regression analysis and ANOVA were used to test the relation between periods of delay and different factors. Odd ratios (OR's) and their correspondent Confidence intervals (95% CI's). Delay periods were studied with Andersen's model. Results: The average duration of delay in our study was 11.9 (${\pm}11.2$) months. Only a quarter of our patients presented early within the first 3 months after onset of their symptoms. About 47.7% arrived later during the course of the first year, while it took beyond that for the last 27% to come. A prior diagnosis of BC was the only predictor of early presentation (for 3-12 months OR=9.6 (p<0.00), 95% CI 9.55-9.75; for >12 months OR=9.3 (p<0.00), 95% CI 9.33-9.33). Out of the 12 different reasons for delay given by our respondents, none showed a significant difference between patients presenting early or late. Financial incapacity (17.5%), ignorance about BC (14.3), and misinterpreting symptoms (12.7%) were the top three whys of delay. Conclusions: Our findings support existence of a non-uniform pattern of delay among Sudanese BC patients. Changing currently adopted awareness elevating strategies into much more inclusive approaches is strongly recommended.

• The Journal of the Korea Contents Association
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• v.10 no.3
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• pp.472-479
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• 2010

The purpose of this paper is to investigates the determinants of learner intention to reuse in e-learning. Based on attitude and flow related studies, our paper proposes a theoretical model consisting of factors such as contents sufficiency, course feedback, self-directed learning, attitude, flow, and reuse intention. The survey method was used for this paper, and data from a total of 409 users in e-learning system were used for this analysis. To analyze the data, structural equation model was used. The results of this empirical study is summarized as follows. First, contents sufficiency has a positive effect on flow as well as attitude, and learner's self-directed learning has a positive effect on flow as well as attitude. Second, both attitude and flow have a positive effect on reuse intention. The findings have significant implications for determinant indicators of reuse intention in e-learning.

• Journal of Navigation and Port Research
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• v.37 no.5
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• pp.447-452
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• 2013

Vessel traffic system uses multiple sea surveillance radars as a primary sensor to obtain maritime traffic information like as ship's position, speed, course. The systematic errors such as the range bias and the azimuth bias of the two-dimensional radar system can significantly degrade the accuracy of the radar image and target tracking information. Therefore, the systematic errors of the radar system should be corrected precisely in order to provide the accurate target information in the vessel traffic system. In this paper, it is proposed that the method compensates the range bias and the azimuth bias using AtoN information installed at VTS coverage. The radar measurement residual error model is derived from the standard error model of two-dimensional radar measurements and the position information of AtoN, and then the linear Kalman filter is designed for estimation of the systematic errors of the radar system. The proposed method is validated via Monte-Carlo runs. Also, the convergence characteristics of the designed filter and the accuracy of the systematic error estimates according to the number of AtoN information are analyzed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.5
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• pp.1042-1048
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• 2017

Recently rapid changes in the industrial environment require new talents in companies. Flipped learning is drawing attention as an effective teaching-learning method. The existing traditional lecture teaching-learning method have various problems that the dropout rates of the student is high and the creative problem solving ability is hindered. In the case of the IT engineering college, most of the major theoretical courses require prior learning of the prerequisite coursework subjects. Therefore, effective teaching-learning methods must be developed to improve student participation and academic achievement. This paper proposes the flipped learning model consisting of five sets that combine the flipped learning and practice to improve student motivation and self - directed learning. Also, this paper analyzes the learning effect by applying it to the algorithm lecture of computer engineering and presents problem and utilization plan according to the result.

• The KIPS Transactions:PartD
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• v.10D no.1
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• pp.101-108
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• 2003

Construction of automated terminal it urgently demanded to gain the foundation of hub-port in north east Asia. Therefore we suggest an adequate operating system layout of automated terminal in Korea. In this paper the aim of automated terminal operating system is satisfied. four basic models are divided according to moving course of export and import cargo of each automated equipments, several input data are changed and analyzed dynamically by Trial and Error method, and then an optimized operating system model is selected, and designed for yard operating system layout on the basis of the selected model. Particularly, the productivity of automated port is up to the kind of automated equipments. However, because expense and present work process must be considered actually. In order to prevent confusion of the work, the method to optimize the present work and substitute prevent equipments and automated equipments was designed. It is a premise that ail the yard equipments described in this paper must be automatic except quay crane.