• Journal of Korean Society of Rural Planning
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• v.24 no.2
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• pp.109-114
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• 2018

In this study, we estimate the greenhouse farmers' willingness to pay of agricultural water supply through pipeline. First, in the questionnaire design, orthogonal design and block design were used to enhance the ease of survey. Second, the theoretical model was constructed through the setting of the probability utility function, and the parameters were estimated by using the conditional logit model. Third, all of the estimation coefficients were statistically significant at the 1% significance level. The results of analysis are summarized as follows. First, the probability of selection is increased when maintenance is carried out by Korea Rural Community Corporation or local government. Second, the probability of selection is increased when agricultural water supply through pipeline is higher than the current level. Third, if the Korea Rural Community Corporation carries out maintenance management, the marginal willingness to pay is 44 won per ton. And if the local government carries out maintenance management, the marginal willingness to pay is 25 won per ton. Fourth, according to the quality level of agricultural water supply, the marginal willingness to pay is 101 won, 114 won and 120 won per ton, respectively. This study can be used as a basic data on the cost setting for agricultural water supply through pipeline.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.4
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• pp.1130-1147
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• 2014

Large size ships have a very flexible construction resulting in low resonance frequencies of the structural eigen-modes. This feature increases the dynamic response of the structure on short period waves (springing) and on impulsive wave loads (whipping). This dynamic response in its turn increases both the fatigue damage and the ultimate load on the structure; these aspects illustrate the importance of including the dynamic response into the design loads for these ship types. Experiments have been carried out using a segmented scaled model of a container ship in a Seakeeping Basin. This paper describes the development of the model for these experiments; the choice was made to divide the hull into six rigid segments connected with a flexible beam. In order to model the typical feature of the open structure of the containership that the shear center is well below the keel line of the vessel, the beam was built into the model as low as possible. The model was instrumented with accelerometers and rotation rate gyroscopes on each segment, relative wave height meters and pressure gauges in the bow area. The beam was instrumented with strain gauges to measure the internal loads at the position of each of the cuts. Experiments have been carried out in regular waves at different amplitudes for the same wave period and in long crested irregular waves for a matrix of wave heights and periods. The results of the experiments are compared to results of calculations with a linear model based on potential flow theory that includes the effects of the flexural modes. Some of the tests were repeated with additional links between the segments to increase the model rigidity by several orders of magnitude, in order to compare the loads between a rigid and a flexible model.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.2
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• pp.1-8
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• 2018

K-means algorithm is one of the most popular and widely used clustering method because it is easy to implement and very efficient. However, this method has the limitation to be used with fixed number of clusters because of only considering the intra-cluster distance to evaluate the data clustering solutions. Silhouette is useful and stable valid index to decide the data clustering solution with number of clusters to consider the intra and inter cluster distance for unsupervised data. However, this valid index has high computational burden because of considering quality measure for each data object. The objective of this paper is to propose the fast and simple speed-up method to overcome this limitation to use silhouette for the effective large-scale data clustering. In the first step, the proposed method calculates and saves the distance for each data once. In the second step, this distance matrix is used to calculate the relative distance rate ($V_j$) of each data j and this rate is used to choose the suitable number of clusters without much computation time. In the third step, the proposed efficient heuristic algorithm (Group search optimization, GSO, in this paper) can search the global optimum with saving computational capacity with good initial solutions using $V_j$ probabilistically for the data clustering. The performance of our proposed method is validated to save significantly computation time against the original silhouette only using Ruspini, Iris, Wine and Breast cancer in UCI machine learning repository datasets by experiment and analysis. Especially, the performance of our proposed method is much better than previous method for the larger size of data.

• Korean journal of applied entomology
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• v.54 no.4
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• pp.311-316
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• 2015

This study was performed to ascertain the potential of egg plant for use as a trap plant to attract Bemisia tabaci adults compared to that of tomato. Choice tests were conducted to compare the preference of B. tabaci adults to horseweed, egg-plant, cucumber, and tomato. B. tabaci adults were found to be more sensitive to visual cues than to odor cues, and they preferred the egg-plant and cucumber to horseweed. The attraction rates of the egg-plant and cucumber to B. tabaci adults were 82.3% and 82.5% respectively, compared to that of tomato. Because egg-plants are easier to manage compared to cucumber, we excluded cucumber from subsequent experiment. The attraction rate of egg-plant to B. tabaci adults was >90% when the height of egg-plant was equal or more than that of the tomato plant.

• The Journal of Advanced Prosthodontics
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• v.1 no.1
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• pp.1-5
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• 2009

STATEMENT OF PROBLEM. Poor wettability of denture relining materials may lead to retention problems and patient discomfort. PURPOSE. Purpose of this study is to compare and evaluate wettability of nine denture relining materials using contact angle measurements under air and water storage over time. MATERIAL AND METHODS. Nine denture relining materials were investigated in this study. Two heat-curing polymethyl-methacrylate(PMMA) denture base materials: Vertex RS, Lang, one self-curing polyethyl-methacrylate(PEMA) chairside reline resin: Rebase II, six silicone relining materials: Mucopren soft, Mucosoft, $Mollosil^{{R}}$ plus, Sofreliner Touch, GC $Reline^{TM}$ Ultrasoft, Silagum automix comfort were used in this experiment. Contact angles were measured using high-resolution drop shape analysis system(DSA 10-MK2, KRUESS, Germany) under three conditions(in air after setting, 1 hour water storage, and 24 hours water storage). Nine materials were classified into three groups according to material composition(Group 1: PMMA, Group 2: PEMA, Group 3: Silicone). Mean values of contact angles were compared using independent samples t-test and one-way ANOVA, followed by a Scheffe's post hoc analysis($\alpha$=0.01). RESULTS. Contact angles of materials tested after air and water storage increased in the following order: Group 1(PMMA), Group 2(PEMA), Group 3(Silicone). Heat-cured acrylic denture base resins had more wettability than silicone relining materials. Lang had the highest wettability after 24 hours of water storage. Silicone relining materials had lower wettability due to their hydrophobicity. Wettability of all denture relining materials, except Rebase II and $Mollosil^{{R}}$ plus, increased after 24 hours of water storage. CONCLUSIONS. Conventional heat-cured resin showed the highest wettability, therefore, it can be suggested that heat-cured acrylic resin is material of choice for denture relining materials.

• Journal of the Korean Institute of Landscape Architecture
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• v.31 no.6
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• pp.95-103
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• 2004

A turfgrass rootzone foundation is one of the important iufluences on the growth of cool-season turfgrass such as Kentucky bluegrass, which is usually grown on korean golf courses and athletic fields in Korea. This study was carried out to evaluate the growth of Kentucky bluegrass on 4 types of turfgrass root-zone foundations: a 2cm thickness of Sand 90%+Peat humus 8%+Zeolite 2% mixture on a subsoil base (C), a 20cm thickness of Sand 90%+Peat humus 8%+Zeolite 2% mixture (S), a 20cm thickness of Sand 45%+fine sand(a sort of Bomyungsa) 45%+Peat humus 8%+Zeolite 2% mixture (S+F), and a 20cm thickness of Sand 45%+fine sand(a sort of Bomyungsa) 45%+Peat humus 8%+Zeolite 2% mixture on a 20cm thick drainage layer (S+F(G)). Visual ratings of Kentucky bluegrass on the C foundation were low throughout the experiment when compared to S, S+F, and S+F(G) foundations, which contained high contents of sand with a high water infiltration rate. However, poor growth of Kentucky bluegrass in the summer of 1991 on the S foundation was likely to be caused by a too high water infiltration rate (185.8cm/hr). The growth of Kentucky bluegrass on the S+F(G) was good while the growth was a little weak at the developing stage on the S +F foundation. If the cost had to be considered when constructing golf courses and athletic fields, The S+F foundation without the drainage layer would be the best choice in terms of low cost and good quality of Kentucky bluegrass compared to the S+F(G). In this result, the infiltration rate was regarded as the most influential factor to the growth of Kentucky bluegrass on rootzone foundations.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.1
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• pp.179-185
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• 2012

Since the eco-era is getting closer, the importance of noise reducing in the passenger cars of high-speed train is very important. The active noise control is best choice to reduce low frequency noise because the passive one is too heavy for high speed trains where weight is so critical. Also ANC is able to reduce the ambient noise when the environmental-factor changes. To reduce a three-dimensional closed-space sound field like a car of a high-speed rail is hard to do using single channel ANC control system. We used multi-channel FXLMS algorithm which calculation speed is fast and the secondary path estimation is possible in order to take into account the physical delay in electro acoustic hardware control loudspeaker and power amplifier. Firstly, we have measured interior noise of KTX and estimated noise path in KTX test-bed. However there was some problem related to algorithm divergence and increasing the filter order. We have made a simulation of interior environment of KTX car by using three frequency bands of 120Hz, 280Hz, 360Hz as the most important for KTX ANC system. During this research the interior noise reduction of KTX car was made by using the multi-channel FXLMS algorithm. Reduction performance was evaluated and compared each other for open space section and tunnel section. in-situ experiment for the KTX noise reduction by proposed ANC was performed based on data obtained in simulation and they were compared for open space section and tunnel section as well.

• Korean Journal of Veterinary Service
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• v.28 no.4
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• pp.367-373
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• 2005

Coccidiosis of domestic fowl is a parasitic disease that infects poultry drastically and can cost the pastured poultry producer much in the course of a year. Two hundred forty, day-old-broiler chicks were purchased and were randomly divided in eight groups, containing thirty birds in each group. Decoquinate $6\%$, maduramicin ammonium $2\%$, monensin sodium $13.2\%$, salinomycin sodium $12\%$, a live attenuated vaccine, and trivalent live attenuated vaccine, was provided to the day chicks of six groups, respectively. The chicks of last two groups served as infected non-medicated and uninfected non-medicated, respectively. Feed consumption, weight gain, feed conversion ratio, mortality and oocyst count per gram feces were recorded during the conduction of the experiment. Among treated groups, performance of salinomycin group was significantly better (p<0.05) in all aspects. Salinomycin acts against the sporozoites, trophozoites and first generation schizonts and is highly effective against the economically important species of Eimeria. The present study confirms that use of salinomycin, as an anticoccidial, is a drug of choice.

• Journal of KIISE:Databases
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• v.37 no.4
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• pp.185-196
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• 2010

Existing methods to compute reverse skyline queries are not correct to process the queries in dataset with region objects which have conditions like a price is 5~7 dollars and a distance to beach is 1km~2km, since they consider datasets with only point objects. To solve the problem, we propose a novel method to process reverse skyline queries for region objects in this paper. It has advantages. First, it is expected to get a good performance, because it is extended from efficient reverse skyline (ERSL) algorithm which is a best algorithm to computing reverse skyline queries in datasets with point objects. Second, it can give a right of choice unlike the others to a person requesting the query. That is because results of reverse skyline have a difference preference according to proposed pruning methods and overlap relations. This algorithm is a first for supporting region objects. Therefore there are not any other algorithms to compare their performance. For that reason, our experiment to prove the efficiency of proposed algorithm is focused what conditions give an effect to its performance and result and how much time it needs to process the query.

• Journal of the Korea Convergence Society
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• v.10 no.9
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• pp.119-126
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• 2019

In this study, we examined whether the intention to choose varies according to the experience of the regret of consumers when experiencing a failure in the status quo or non-status quo, and how self-compassion plays a moderating role in this relationship. A experiment was conducted to achieve the purpose of the study. First, this study also confirmed that regret was a mediator between dissatisfaction with choice outcomes and behavioral intentions. Second, like previous studies, this study confirmed the effect of status quo in general. However, it can be seen that the effect depend on self-compassion. Or, the regrets of those with high self-compassion and their future behavioral intentions did not change significantly whether it was wrong due to maintaining on or changing of the status quo. On the other hand, those with low self-compassion showed the bigger differences, so they were typically showing the status quo effect.