• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.443-450
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• 2017

Nowadays, Power Line Communication (PLC) is gaining high attention from industry and electric supply companies for the services like demand response, demand side management and Advanced Metering Infrastructure (AMI). The reliable services to consumers using PLC can be provided by utilizing an efficient PLC channel for which sophisticated channel modeling is very important. This paper presents characterization of a Low Voltage (LV) access network for Narrowband Power Line Communications (NB-PLC) using transmission line (TL) theory and a Simulink model. The TL theory analysis not only includes the constant parameters but frequency selectivity is also introduced in these parameters such as resistance, conductance and impedances. However, the proposed Simulink channel model offers an analysis and characterization of capacitive coupler, network impedance and channel transfer function for NB-PLC. Analysis of analytical and simulated results shows a close agreement of the channel transfer function. In the absence of a standardized NBPLC channel model, this research work can prove significant in improving the efficiency and accuracy of NB-PLC communication transceivers for Smart Grid communications.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.4
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• pp.302-311
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• 2016

This paper proposes a hybrid ESS that integrates an energy storage system (ESS) with an uninterruptible power supply (UPS). The hybrid ESS has a demand management and emergency power supply function while increasing the battery utilization of the UPS, which has just been used in a power failure. In addition to the critical load, the proposed system augments the capacity of emergency generation using an additional load, which has voltage and frequency-dependent characteristics to the grid side. The control algorithm of the AC-DC converter and bidirectional DC-DC converter is proposed for demand management and emergency power supply. Furthermore, seamless and autonomous transfer methods to alleviate the transient during mode transfer are proposed. To validate the proposed control scheme, experimental results from a 5 kW prototype are provided.

• The Journal of Fisheries Business Administration
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• v.48 no.2
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• pp.1-17
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• 2017

This work studies the variability of flatfish sales revenue. The theoretical analysis draws functions for equilibrium price and quantity using expectation hypotheses. The functions include unpredictable phenomenon with dummy variable and GARCH. The equilibrium function, using adaptive expectation hypothesis, contains the independent variables of supply and demand, while the equilibrium function, embodying rational expectation hypothesis, includes only the independent variables of supply side, because the demand side disappears by the information extraction process theoretically, if economic subjects build the expectation rational. The empirical analysis shows: the variability of flatfish production has a spillover effect on the variability of revenue with the adaptive expectation hypothesis. In the case when the model has a rational expectation hypothesis, the variability of flatfish production has a spillover effect on the revenue (the mean equation of GARCH model). This study indicates that there is the variability in flatfish production and sales revenue, and the spillover effect between them. The result can help to build of the rational system for the fishery income stability.

• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.1
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• pp.14-19
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• 2009

In Mobile Ad-hoc Network, link failure and packet loss may occur frequently due to its nature of mobility and limited battery life. In this paper, an enhanced robust routing protocol based on AODV(Ad hoc On-demand Distance Vector routing) by monitoring variation of receiving signal strength is proposed. New metric function that consists of node mobility and hops of path is used for routing decision. For preventing route failure by node movement during data transmission, a new route maintenance is presented. If the node movement is detected, the routing agent switches local path to its neighbor node. Simulation results show that the performance of the proposed routing scheme is superior to previous AODV protocol.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.904-913
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• 2005

This paper deals with an integrated problem of inventory control and dynamic pricing strategies for a commodity with price and sales-period dependent demand pattern, where a seller and customers have complete information of each other. The problem consists of two parts; one is each buyer's benefit problem which makes the best decision on price and time for buyer to purchase items, and the other one is a seller's profit problem which decides an optimal sales strategy concerned with inventory control and discount schedule. The seller's profit function consists of sales revenue and inventory holding cost functions. The two parts are closely related into each other with some related variables, so that any existing general solution methods can not be applied. Therefore, a simplified model with single seller and two customers in considered first, where demand for multiple units is allowed to each customer within a time limit. Therewith, the model is generalized for a n-customer-classes problem. To solve the proposed n-customer-set problem, a dynamic programming algorithm is derived. In the proposed dynamic programming algorithm, an intermediate profit function is used, which is computed in case of a fixed initial inventory level and then adjusted in searching for an optimal inventory level. This leads to an optimal sales strategy for a seller, which can derive an optimal decision on both an initial inventory level and a discount schedule, in $O(n^2)$ time. This result can be used for some extended problems with a small customer set and a short selling period, including sales strategy for department stores, Dutch auction for items with heavy holding cost, open tender of materials, quantity-limited sales, and cooperative buying in the on/off markets.

• Korean Journal of Agricultural Science
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• v.16 no.1
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• pp.71-83
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• 1989

The purpose of this research are to forecast the demand and supply of milk in Korea, and to obtain information for attitudes affecting milk consumption, which is necessary to make a plan for increasing milk consumption in Korea. The estimation of the milk demand and production was made by the multiplicative decomposition method and the statistical function. Data on consumer were collected from 737 students who were attending primary school, middle school and university in Daejeon during the period of July 11 to July 21, 1988. The results obtained are as follows; 1. The prediction results showed that the production for milk will over supply 21,900 tons in 1,990, 70,800 tons in 1,995 by the multiplicative decomposition method and 45,400 tons in 1990, -51,500 tons in 1995 by the statistical function. 2. It was found that almost all the students awared milk as essential food-stuff of common food stuff for the Koreans. 3. Quite a few students were apt to believe that milk processors added water into fluid milk. 4. Most students showed obtaining information about the nutritional value of milk by school education and advertising of TV, Radio, and Printed media. 5. However, it was found that the advertising by TV, Radio, and Printed media did hardly give to consumers influences on the choice of a particular milk brand. Accordingly, the conclusions are as follows; 1. Need to provide consumers with well planned education programs on the nutritional value of milk. 2. Heavy brand advertising for fluid milk may mislead the understanding of consumer, since city milk is not much differentiated in Korea. Therefore the milk processors should put more efforts in generic milk promotion by reducing brand advertizement. 3. The milk processors should provide major portion of financing for generic milk promotion program.

• 사회경제평론
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• v.29 no.1
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• pp.1-29
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• 2016

This paper looks critically, in the light of the Capital Controversies of the 1950s and the 1960s, at the Neoclassical claim that the Funded-Pension system is economically superior to the Pay-As-You-Go (PAYG) pension system. This claim rests crucially upon the inverse relation between the rate of interest and the volume of investment (the investment demand function) and the positive relation between the capital intensity and labour productivity (the 'intensive- form' production function), The Capital Controversies proved that the two relations do not always hold; then, the claim in question loses much of its ground. Further, the absensce of the relations makes plenty room for effective demand in determining the level of income and the volome of employment even in the long period. This positive role of effective demand in the long period highlights the problems of the Funded-Pension system and, at the same time, supports the competitiveness of the PAYG pension system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.313-320
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• 2021

This study develops a demand and supply model and price model for Miryang sesame leaf cultivation and predicts the optimal production level to maximize total profit for Miryang sesame leaf farms. We used time series data from 1996 to 2017, which are related to Miryang sesame leaf cultivation. For the analysis, we estimated the demand function and average cost function, calculated the optimal production level and price, and derived the optimal profit. In addition, we predicted the optimal production level, price, total revenue, total cost, and profit until the year 2030 through scenario analysis. The results show that the optimal production level until the year 2030 is between 10 and 12.5 thousand tons, while the production volume was 7 thousand tons in 2017, and total profit for Miryang sesame leaf farms is estimated at 13.3 to 21.3 billion Korean won in 2030. The producer group needs to maintain the optimal production level to maximize total profit for farmers, as suggested in this study.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.257-262
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• 2023

As part of their marketing policy, some suppliers allow retailers a period of credit in anticipation of increasing demand for the products they supply. The opportunity to defer payments on products through credit transactions has the effect of reducing retailers' inventory investment costs, and as a result, retailers determine selling prices in anticipation of increased demand from buyers. This study aims to analyze the inventory model that determines the retailer's selling price and EOQ(Economic Order Quantity) under the assumption that the buyer's demand is an exponentially decreasing function of the retailer's selling price in the credit transaction supply chain consisting of suppliers, retailers, and buyers. The products supplied for problem analysis include the case of deteriorating products that deteriorate over time, and the effect of the credit transaction period, the index of price elasticity and the degree of deterioration on the retailer's selling price and EOQ is analyzed.

• Journal of TMJ Balancing Medicine
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• v.13 no.sup
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• pp.9-14
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• 2023

Objectives: The purpose of this study was to investigate patients' demand for music and art therapy in the treatment of Parkinson's disease and to understand how patients view the use of music and art therapy as a complementary form of treatment that can improve their quality of life and increase their self-efficacy in addition to medication. Methods: To this end, 60 Parkinson's patients visiting Daejeon Korean Medicine Hospital at Daejeon University were surveyed about music and art therapy. Results: The survey demonstrated a highly positive response to the music program, with strong belief in its efficacy for Parkinson's disease and significant interest in participation. Group music therapy was perceived as effective for enhancing mental health, respiratory function, language disorders, and overall quality of life. Although the art program was also deemed effective, patients showed slightly lower interest and willingness to participate compared to music therapy. The patients preferred 60-minute sessions once a week for about 8 weeks. Conclusions: We propose the following directions for a Parkinson's music and art therapy program. First, develop a once-a-week, 8-week music and art program for Parkinson's patients. Second, design the music program to focus on improving respiratory function and quality of life. Third, the art program focuses on creating a sense of security and comfort through emotional exchange among patients and improving self-efficacy.