• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.496-504
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• 2011

The region trunk line railroad route undergoes an influence on a large scale in train operation systematic reorganization. This keynote of the train operation not being to the consumer and not to be is because being to the supplier. The trunk line route user of region supply change of the supplier sensitively, accepts but, the demand unit will be able to change the supply massive demanders does not become and like that to accept this back is not the railroad the mean of transportation which grudge is different a mean of transportation mainly makes use. This hits to neither the gist of GLORY promotions of the railroad public corporation which pursues the railroad use which is ordinary even in the basis of governmental policy of stock of coal small green growth and not to be is arranged. For the railroad use activation of the region trunk line route consequently and to excavate the demand hindrance element and a demand lure element the inside and the outside defines and to observe the fluctuation of use importing in existing train operation systematic fluctuation, with the user tries analyzes the instance of the overseas railroad enterprise about the process which reflects the opinion of the area and improvement under preparing boil.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2009년도 정기총회 및 추계학술대회 논문집
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• pp.287-289
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• 2009

This paper deals with a parallel processing uninterruptible power supply (UPS) for sudden voltage fluctuation in computer applications to integrate power quality improvement, load voltage stabilization and UPS. To reduce the complexity, cost and number of power conversions, which results in higher efficiency, only one voltage-controlled voltage source inverter (VCVSI) is used. The system provides sinusoidal voltage at the fundamental value of 220V/60Hz for the load during abnormal utility power conditions or grid failure. Also, the system can be operated to mitigate the harmonic current and voltage demand from nonlinear loads and provide voltage stabilization for loads when sudden voltage fluctuation occur, such as sag and swell. System operation simulation demonstrates that the system protects against outages caused by abnormal utility power conditions and sudden voltage fluctuations and changes.

• 조명전기설비학회논문지
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• 제25권11호
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• pp.39-49
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• 2011

Smart Grid has two main objectives on both supply and demand aspects which are to distribute the renewable energy sources on supply side and to develop realtime price responses on demand side. Renewable energy does not consume fossil fuels, therefore it improves the eco-friendliness and saves the cost of power system operation at the same time. Demand response increases the flexibility of the power system by mitigating the fluctuation from renewable energies, and reduces the capacity investment cost by shedding the peak load to off-peak periods. Currently Smart Grid technologies mainly focus on energy monitoring and display services but it has been proved that enabling technologies can induce the higher demand responses through many pilot projects in USA. On this context, this paper provides a price responsive algorithm for HEMS (home energy management system) on the real time pricing environment. This paper identifies the demand response as a core function of HEMS and classifies the demand into 3 categories of fixed, transferable, and realtime responsive loads which are coordinated and operated for the utility maximization or cost minimization with the optimal usage combination of three kinds of demand.

• 한국전기전자재료학회논문지
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• 제36권6호
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• pp.570-575
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• 2023

Demand and necessity for eco-friendly offshore wind farms have been increasing. Research on submarine cables is constantly being considered for a reliable and stable power transmission. This study aimed to evaluate the thermal aging characteristic of submarine cables inside the J-tube of offshore wind farms. In this study, a submarine cable was set in three sections: The first is the part exposed to the air above the sea level at high temperature. The second is the section exposed to repeated temperature fluctuation as the sea level rises and falls. The third is the part submerged at low temperature below the sea level. Aged samples were tested by using the method of electrical evaluation to obtain insulation characteristics. The experimental results show that the dielectric breakdown of the sample with temperature fluctuation was 7% lower than the sample with a constant temperature; thereby, demonstrating that the section where the temperature fluctuation occurred in the submarine cables was weaker than the other. The sections of submarine cable with temperature fluctuations are believed as a weak point during operation; therefore, this part should be monitored preferentially.

• 산업경영시스템학회지
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• 제32권3호
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• pp.93-98
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• 2009

This paper studies that $\sigma$ values(10, 20, 50) and $\rho$ values(-0.6, -0.3, 0.0, 0.3, 0.6) affect the total inventory cost of a supply chain and order fill rate when the market demand process follows a general auto-correlated AR(1) process without seasonality. $\sigma$ indicates the degree of demand fluctuation and $\rho$ means the trend of demand. ANOVA tests using a 5% significance level are performed in SPSS to examine significant performance changes among various cases.

• 한국조경학회지
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• 제19권2호
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• pp.12-22
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• 1991

The purpose of this study is to identify demand and methods of projection, including to prove the variables affecting the fluctuation of visitors and to analyze the relationship between these variables in National Park. Statistical analysis method (Multiple Linear Regression Analysis, ANOVA, and Model diagnostics) was carried out by computer program SAS/pc. 13 variables (1. Total Population, 2. Per Capita PDI, 3. Employment Ratio of S.O.C. & others, 4. NO. of Passenger Car, 5. Length of Roads, 6. Leisure Expenditure of Farm Household, 7. Leisure Expenditure of Urban Household, 8. Price Index, 9. NO. of Bus, 10. Exchange on Dollars, 11. Export, 12. Import, and 13. Visitors in National Park) had been used to this study. The scope of time period is during the last 17 years (1970-1986). The results were as follows; 1) Participation depends only on the specific characteristics of the economic factors (Price Index and Leisure Expenditure of Urban Household). These factors are the importance factors directly affecting the participation of visitors. The statistical Model for projecting the visitors in National Parks is the function of "Visitors in National Parks (thousand)=14915+0.210311*Leisure Expenditure of Urband Household (won)-157.835619*Price Index(1985=100)" 2) The external factors affecting the participation depends upon the interelated features of availability and accessibility (NO. of Passenger Car, Length of Roads, and NO. of Bus) of recreation resources or sites, and the economic factors (Per Capita PDI, Export, and Import). These factors are the factors indirectly affecting the participation of visitors. 3) The participation depends on the specific characteristics of demographic factors (Total Population and Employment Ratio of S.O.C. & others). These factors are the factors indirectly affecting the participation of visitors. 4) The unexpected fluctuation of yearly visitors depends on oil shock or inflation (1971, 1973-1974, 1979-1980), promulgation of national emergency decrees (1971-1972, 1974-1975, 1979-1980), and national events (assassination of president Park's wife, Madame Yuk in 1974 and president Park I 1979).

• 노동경제논집
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• 제31권1호
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• pp.1-27
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• 2008

본 연구는 최근 노동시장의 특정인 임시 일용직 증가의 원인을 분석하였다. 임시 일용직 증가 원인으로 기업의 수익성, 시장 변동성, 근로자의 자질에 대한 불확실성 측면에서 살펴보았다. 결과에 따르면 제조업의 경우 기업의 수익성과 건설업과 도소매업은 상품수요의 변동성과 관련이 깊은 것으로 나타났다. 한편 1990년대 이후 증가한 교육의 양적 팽창이 질적 향상을 수반하지 못한 결과 근로자의 자질에 대한 불확실성을 증가시키면서 기업은 상용직보다 임시 일용직을 선호하게 되었을 가능성도 간접적으로 확인되었다.

• 대한임베디드공학회논문지
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• 제14권2호
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• pp.71-78
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• 2019

As the capacity of SSDs rapidly increases, the amount of DRAM to keep a mapping table size in SSDs becomes very huge. To address a Demand-based FTL (DFTL) scheme that caches part of mapping entries in DRAM is considered to be a feasible alternative. However, owing to its unpredictable behaviors, DFTL fails to provide consistent I/O response times. In this paper, we a) analyze a root cause that results in fluctuation on read latency and b) propose a new demand-based FTL scheme that ensures guaranteed read response time with low write amplification. By preventing mapping evictions while serving reads, the proposed technique guarantees every host read requests to be done in 2 NAND read operations. Moreover, only with 25% of a cache ratio, the proposed scheme improves random write performance and random mixed performance by 1.65x and 1.15x, respectively, over the traditional DFTL.

• 대한산업공학회지
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• 제3권1호
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• pp.39-47
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• 1977

Most of the current literature on inventory theory has been devoted to the study of single stage models. A class of inventory problems which is of great interest is the multistage inventory system which involves a series and hierarchical sequence of stations. This study analyzes some aspect of the series type and multi-stage inventory system, using the fixed cycle ordering which bas a modificatory control function in the system equations. The objective of this study is to clarify the dynamic behavior of the system. The author has derived the theoretical formulas of variation of ordering quantity and stock fluctuation of each stage due to power spectral density function. Influence of parameters such as, (1) intensity of autocorrelation of demand sequence ($\lambda$), (2) forecasting exponential smoothing factors of each stage (${\alpha}_1,\;{\alpha}_2,\;{\alpha}_3$) and (3) production control factor of the 3rd stage ($\gamma$), as operators of the system on the variation of ordering quantity and stock fluctuation of the system. is also clarified. As a result of this study, the relations between the variation of ordering quantity, stock fluctuation and the parameters of the system, have been found. The principles and the theorical analysis presented here will be applicable to more complex type of discrete control systems in constructing the specific condition of the system to minimize inventory variances.

• 한국멀티미디어학회논문지
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• 제25권2호
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• pp.345-352
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• 2022

Conducting AI-based fusion business due to the increment of ICT fusion medical device has been expanded. In addition, AI-based medical devices help change existing medical system on treatment into the paradigm of customized treatment such as preliminary diagnosis and prevention. It will be generally promoted to the change of medical device industry. Although the current demand forecasting of medical biotechnology commercialization is based on the method of Delphi and AHP, there is a problem that it is difficult to have a generalization due to fluctuation results according to a pool of participants. Therefore, the purpose of the paper is to predict demand forecasting for identifying promising technology based on building up big data in medical biotechnology. The development method is to employ candidate technologies of keywords extracted from SCOPUS and to use word2vec for drawing analysis indicator, technological distance similarity, and recommended technological similarity of top-level items in order to achieve a reasonable result. In addition, the method builds up academic big data for 5 years (2016-2020) in order to commercialize technology excavation on demand perspective. Lastly, the paper employs global data studies in order to develop domestic and international demand for technology excavation in the medical biotechnology field.