• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.4
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• pp.80-87
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• 2015

The proliferation of the Internet and communication technologies and applications, besides the conventional retailers, has led to a new form of distribution channel, namely home sopping through the telephone, TV, catalog or the Internet. The conventional and new distribution channels have different transaction costs perceived by the consumers in the following perspectives: the accessibility to the product information, the traffic cost and the opportunity cost for the time to visit the store, the possibility of 'touch and feel' to test the quality of the product, the delivery time and the concern for the security for the personal information. Difference in the transaction costs between the distribution channels results in the different selling prices even for the same product. Moreover, distribution channels with different selling prices necessarily result in different business surpluses. In this paper, we study the multilateral bargaining strategy of a manufacturer who sells a product through multiple distribution channels with different transaction costs. We first derive the Nash equilibrium solutions for both simultaneous and sequential bargaining games. The numerical analyses for the Nash equilibrium solutions show that the optimal bargaining strategy of the manufacturer heavily depends not only on the degree of competition between the distribution channels but on the difference of the business surpluses of the distribution channels. First, it is shown that there can be four types of locally optimal bargaining strategies if we assume the market powers of the manufacturer over the distribution channels can be different. It is also shown that, among the four local optimal bargaining strategies, simultaneous bargaining with the distribution channels is the most preferred bargaining strategy for the manufacturer.

• Journal of Biosystems Engineering
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• v.2 no.1
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• pp.33-48
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• 1977

Transporting agricultural products and the other material by the two-wheel-tractor (power-tiler)and trailer system may be one of its most widely used farming functions.The safety and hitching load for all the previaling performing conditions may be the general concern over the operation of the tiller-trailer system. In this study, a mathematical model to determine the static and dynamic forces excerting on the hitch point were developed . Based on the analysis of the model and the field measurements. the limiting hitching load and critical slope were analyzed. The results of the study are summarized as follows ; 1) The limit angle of slope land for the safety steering that two-wheel tractor-single axle trailer system was able to transport agricultural products was the direct angle (${\gamma}$) = 8 ; the cross angle$\beta$) 15 ; and it was decreased in accordance with the increase of carrying load ($W_4). 2) The critical velocity for safe operation in case of running on downward hill road was about 1.08m/sec. 3) The limiting carrying load for the safe steering was W$_4$=600kg. The degree of the safe steering for different braking methods was given in order as follows ; Simulataneous braking the tractor and trailer , braking the trailer only, and braking tractor only. 4) Among the three components of impact loads excerting on the hitch point, the component in the lateral direction ($P_{Vy}$) was near zero in spite of increase of hitching load ($W_4) , while the components in the other two mutually perpedicular directions ($P_{Vx}$ and ($P_{Vz}$) ) had larger values in horizontal plane than those in the slope lands. 5) Moment of forces on the lateral direction (M$y$) had the largest value among the three components of impact moment acting on the hitch point, however all the components were sharply increased in accordance with the increase of hitching loads ($W_4. Three components of the moment were the negative values.

• Geomechanics and Engineering
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• v.31 no.6
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• pp.545-556
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• 2022

Evaluation and optimization of tunnel wall convergence (TWC) plays a vital role in preventing potential problems during tunnel construction and utilization stage. When convergence occurs at a high rate, it can lead to significant problems such as reducing the advance rate and safety, which in turn increases operating costs. In order to design an effective solution, it is important to accurately predict the degree of TWC; this can reduce the level of concern and have a positive effect on the design. With the development of soft computing methods, the use of deep learning algorithms and neural networks in tunnel construction has expanded in recent years. The current study aims to employ the long-short-term memory (LSTM) deep neural network predictor model to predict the TWC, based on 550 data points of observed parameters developed by collecting required data from different tunnelling projects. Among the data collected during the pre-construction and construction phases of the project, 80% is randomly used to train the model and the rest is used to test the model. Several loss functions including root mean square error (RMSE) and coefficient of determination (R²) were used to assess the performance and precision of the applied method. The results of the proposed models indicate an acceptable and reliable accuracy. In fact, the results show that the predicted values are in good agreement with the observed actual data. The proposed model can be considered for use in similar ground and tunneling conditions. It is important to note that this work has the potential to reduce the tunneling uncertainties significantly and make deep learning a valuable tool for planning tunnels.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.1
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• pp.50-61
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• 2019

The concern on the greenhouse gas emissions is increasing globally. Especially, the greenhouse gas emission from fisheries is an important issue from the Paris Climate Change Accord in 2015. Furthermore, the Korean government has a plan to reduce the GHG emissions as 4.8% compared to the BAU in fisheries until 2020. However, the investigation on the GHG emissions from Korean fisheries rarely carried out consistently. Therefore, the quantitative analysis of GHG emissions from Korean fishery industry is necessary as a first step to find a relevant way to reduce GHG emissions from fisheries. The purpose of this research is to investigate which degree of GHG emitted from the major offshore fisheries such as offshore gillnet fishery, offshore longline fishery, offshore jigging fishery and anchovy drag net fishery. Here, we calculated the GHG emissions from the fisheries using the Life Cycle Assessment method. The system boundary and input parameters for each process level are defined for the LCA analysis. The fuel use coefficients of the fisheries are also calculated according to the fuel type. The GHG emissions from sea activities by the fisheries will be dealt with. Furthermore, the GHG emissions for the unit weight of fishes are calculated with consideration to the different consuming areas as well. The results will be helpful to understand the circumstances of GHG emissions from Korean fisheries.

• The Journal of the Korean dental association
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• v.54 no.6
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• pp.429-437
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• 2016

Objectives: Photodynamic therapy has been proven to promote additional clinical and microbiological benefits in the treatment of chronic periodontitis and aggressive periodontitis. The purpose of this study is to assess the effectiveness of the photodynamic therapy for patient with periodontitis. Methods: We searched the eight Korean databases and Ovid-MEDLINE, Ovid-EMBASE, Cochrane Library. Total 300 studies were searched and 13 studies were included in the final assessment. Each of the stages from literature search and extraction of data were carried out independently by 2 researchers. We used tools of Scottish Intercollegiate Guidelines Networks for assessment of the quality of studies. Results: The safety of the photodynamic therapy was assessed by bleeding. The effectiveness of the photodynamic therapy was assessed by the reduction of Probing pocket depth (PPD) and the gain of Clinical attachment level (CAL). The mean difference of PPD was 0.46(95% CI 0.09~0.82), (p=.01).). The mean difference of CAL was ?0.49(95% CI ?1.12~0.14), (p=.13). Conclusion: The additional use of $^{\circ}{\infty}$Antimicrobial Photodynamic Therapy for Periodontitis$^{\circ}{\pm}$ caused hemorrhage to similar extents to conventional treatment modalities, where scaling and root planing are solely performed, in patients with periodontitis who are expected to have a lower degree of treatment response to non-surgical or surgical periodontal therapies (implant or refractory periodontitis) and those where there is a concern for the possible occurrence of antimicrobial side effects or resistance. This indicates that there are no problems with its safety. But there were no consistent reports about the effects of the additional use of photodynamic therapy. This led to a decision that the safety and efficacy of the current technology deserve further studies (Recommendation rating of A, Classification of technology II-a).

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.3
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• pp.78-85
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• 2004

The non-planned development of the rural area surrounding the Metropolitan area has become a social problem. The land development program until now has an aspect of not combining the spacial plan and the environmental plan. The land use and city development system based on development should change into a form that combines developing the area and conserving the environment. Therefore, this research attempts to compare the results of the overlay analysis and the gravity matrix which are ways to evaluate the value land that has a high environmental conservation value. The research area is the town of Seonggeo-eup, Cheonan City, and the reason for selecting this area is because it is expected to be densely populated as a connected area to the Metropolitan and the development pressure, such as expanding the industrial area, is high due to convenient transportation. The environmental factors used in the research are the relative altitude, incline, age-class, natural degree of the ecology, classification of the land covering and the NDVI, and the research methods used are the overlay analysis of the GIS and the statistical method. The overlay analysis results showed level 1 13.2%, level 2 30.7%, level 3 47.4%, level 4 1.0%, level 5 2.4%, level 6 5.4% and so on. The gravity matrix was classified as level 1 27.0%, level 2 9.3%, level 3 58.2%, level 4 2.4%, level 5 2.3%, level 6 0.9% and so on. These results are more appropriate than current methods for plans that value the environment because the analyzed results of the gravity matrix have a tendency to highly condense the environmentally valuable area. Consequently, if the spacial and environmental plans combine and therefore expand the efficient use of the land in the current state where the nation's concern in environment is getting higher, it is thought that it will contribute highly on the development of the nation's life quality.

• Korean Institute of Interior Design Journal
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• v.26 no.2
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• pp.3-12
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• 2017

This study has analyzed the features of attention to spacial composition seen in "Seeing ${\leftrightarrow}$ Seen" Correlation of continuous move in the space. The eye-tracking was employed for collecting the data of attention features to the space so that the correlation between visual perception and space could be estimated through the attention features to the difference between spacial composition and display. First, it was confirmed that the attention features varied according to the structure of shops and the exposure degree of selling space, which revealed that, while causing the customers' less attention to both sides of shops, the vanishing-point structure characteristically made their eyes focused on the central part. Second, their initial observation activities were found to be active at the height of their eyes. Third, 10 images were selected as objects for continuous experiment. There was a concern that the central part of each image would be paid intense attention to during the initial observation, but only two of those were found to be so. Fourth, there had been a study result of eye-tracking experiment that the attention had been concentrated on the central part of the image first seen. This study, however, revealed that such phenomenon is limited to the first image. Accordingly, it is necessary to draw up such method for ensuring reliability in order to use the data acquired from any eye-tracking experiment as exclusion of the initial attention time to the first image or of unemployment of the initial image-experiment to analysis.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.1
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• pp.77-88
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• 2017

The concern on the greenhouse gas emissions is increasing globally. Especially, the greenhouse gas emission from fisheries is an important issue due to Cancun Agreements Mexico in 1992 and the Kyoto protocol in 2005. Furthermore, the Korean government has a plan to reduce the GHG emissions as 5.2% compared to the BAU in fisheries until 2020. However, the investigation on the GHG emissions from Korean fisheries has not been executed much. Therefore, the quantitative analysis of GHG emissions from Korean fishery industry is needed as the first step to find a relevant way to reduce GHG emissions from fisheries. The purpose of this research is to investigate which degree of GHG emitted from the major coastal fisheries such as coastal gillnet fishery, coastal dual purpose fishery, coastal pots fishery and coastal small scale stow net fishery. Here, we calculated the GHG emission from the fisheries using the LCA (Life Cycle Assessment) method. The system boundary and input parameters for each process level are defined for LCA analysis. The fuel use coefficients of the fisheries are also calculated according to the fuel type. The GHG emissions from sea activities by the fisheries will be dealt with. Furthermore, the GHG emissions for the unit weight of fishes are also calculated with consideration to the different consuming areas. The results will be helpful to understand the circumstances of GHG emissions from Korean fisheries.

• The Korean Journal of Food And Nutrition
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• v.29 no.6
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• pp.878-888
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• 2016

The purpose of this study was to examine the relationship between the smoking and eating habits of high school students. We also presented the basic data for the effective smoking cessation and smoking prevention programs, and proper nutrition education programs. We surveyed 304 high school male students in Sokcho city. The results were as follows ; a total of 23.7% of the subjects were smokers, the smokers spent more pocket money than the non-smokers and they also spent more time on the internet or smartphone. The smokers had lower awareness of the dangers of smoking than that of non-smokers. They started drinking alcohol earlier than the non-smokers. Their water intake was higher and they preferred consumption of high-protein foods like fried chicken, but were not inclined to vegetables and sour tasting foods. These results imply that smoking habits of the subjects affected their eating and drinking habits. A matter of concern was the low intake of vegetables and sour tasting foods, which could lead to a deficiency of nutrients such as vitamins, minerals and dietary fibers. The smokers were less satisfied with their school life than the non-smokers. There was a negative correlation with the degree of awareness of the dangers that smoking can cause. Conversely, the amount of smoking and drinking habits were positively correlated. To reach a healthy adulthood, it is crucial to quit smoking and participate in smoking prevention education along with nutrition education and abstinence education for the adolescents.

• Research in Community and Public Health Nursing
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• v.15 no.4
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• pp.639-647
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• 2004

Purpose: The purpose of this study was to analyze the need for hospice care programs in families of patients with cancer. Method: The study surveyed 98 families who were taking care of patients with cancer. This survey was conducted from August 2004 to October 2004 at two general hospitals in Seoul. The data were collected through a self-reporting questionnaire of 22 items. The items were classified into five areas by factor analysis to identify the construct validity. The reliability of the tool was established by Cronbach's alpha as .93 and the data collected were analyzed by descriptive statistics, t-test and ANOVA. Results: 1) The degree of need for hospice care of the subjects showed a high average of $3.26({\pm}3.7$). The need for 'emotional care of patients showed the highest mean' (M=3.47), 'management of terminal physical symptoms' (M=3.34), 'control of secondary physical problems' (M =3.26), 'acceptance of the family's difficulty' (M=3.12), 'spiritual care for preparing for death' (M=2.96), respectively. 2) With respect to the demographic characteristics of the subjects, there were statistically significant differences in hospice care needs, according to the onset of diagnosis (F=3.110, p=.030). Conclusion: Hospice care must be provided considering the needs of families of patients with cancer. In this sense, this country's needs as well as hospice nurses' higher concern and support for hospice care of patients require further education and program development to meet the current demands.