• Title, Summary, Keyword: Expected efficiency

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Evaluation on the Expected Purification Efficiency of Air Ion and Analysis on the Generated Amount of Negative Air Ions by Plants for the Purification of Particulate Matter in Air (지표대기 미세먼지 정화를 위한 식물체 음이온 발생량 분석 및 음이온의 미세먼지 기대정화지수 평가)

  • Oh, Deuk-Kyun;Ju, Jin-Hee
    • Journal of Environmental Science International
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    • v.29 no.6
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    • pp.623-631
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    • 2020
  • This study analyzes the effect of negative air ions on the concentration of airborne particulate matter and evaluates the expected purification efficiency of open spaces for particulate matter by investigating the amount of negative air ions generated by plants. This study establishes a negative air ion generation treatment environment, plant environment, and control environment to measure the purification efficiency of particulate matter under the conditions of each, analyzing the expected purification efficiency by designing a particulate matter purification model. Results show that the amount of generated negative air ion according to environment was negative air ion generation treatment environment > plant environment > control environment; this order also applies to the particulate matter purification efficiency. Moreover, it took 65 min for the negative ion generation treatment environment, 90 min for the plant environment, and 240 min for the control environment to reach the standard expected purification efficiency of particulate matter concentration of 960 mg/㎥ for PM10. For PM2.5, with the designated maximum concentration of 700 mg/㎥, it took 60 min for the negative ion generation treatment environment, 80 min for the plant environment, and more than 240 min for the control environment. Based on these results, the expected purification efficiency compared to the control environment was quadrupled in the negative ion generation treatment environment and tripled in the plant environment on average.

Analyzing Expected Inflation Based on a Term Structure Model: A Case of Korea (이자율모형을 이용한 우리나라 기대인플레이션의 추정 및 특징)

  • Song, Joonhyuk
    • KDI Journal of Economic Policy
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    • v.36 no.2
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    • pp.65-101
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    • 2014
  • This paper estimates and characterizes expected inflations using an affine term structure model based on the empirical stochastic process of the interest rates in Korea. The empirical results show that the expected inflation which marked above 4% before the global financial crisis has dampened and stabilized after the crisis. Moreover, we investigate the rationality of the various expected inflation measures in terms of the unbiasedness and efficiency and find that unbiasedness is not rejected across the all measures, while the efficiency cannot be empirically warranted. Besides, we run Granger causality tests and conclude that the expected inflations compiled from the Consensus, BOK-Expert have the cross-causality with the long-run actual inflation, while the expected inflation estimated from the term structure model has the cross-causality with the short-run actual inflation. These results connote that expected inflations collected from different sources and methods have their targets and horizons and the central bank needs to watch all of them with a balanced view instead of preferring one to the other.

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Evaluation of the Effects of the Longitudinal Baffle on Settling Efficiency within Rectangular-shaped Sedimentation Basin (장방형 침전지내 도류벽의 침전효율에 대한 영향 평가)

  • Park, No-Suk;Kim, Seong-Su;Seo, In-Seok;Min, Kyong-En
    • Journal of Korean Society of Water and Wastewater
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    • v.23 no.5
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    • pp.573-581
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    • 2009
  • In the case that the average velocity within rectangular-shaped sedimentation basin is less than 1.5cm/sec, and Froude number less than $10^{-6}$, it can not be expected that the longitudinal baffle improves the sedimentation efficiency. Also, since relatively lower velocity increases the effect of geostrophic body force, asymmetric flow pattern on a plane occurs within the basin. From the results of CFD (Computational Fluid Dynamics) simulation, in the case that the highest velocity within rectangular-shaped sedimentation basin is over 1.5cm/sec, and Froude number over $10^{-6}$, it can be expected that the longitudinal baffle installed within rectangular-shaped sedimentation basin improves the sedimentation efficiency.

Numerical Investigation of Purcell Enhancement of the Internal Quantum Efficiency of GaN-based Green LED Structures

  • Choi, Young-Hwan;Ryu, Guen-Hwan;Ryu, Han-Youl
    • Current Optics and Photonics
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    • v.1 no.6
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    • pp.626-630
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    • 2017
  • GaN-based green light-emitting diode (LED) structures suffer from low internal quantum efficiency (IQE), known as the "green gap" problem. The IQE of LED structures is expected to be improved to some extent by exploiting the Purcell effect. In this study, the Purcell effect on the IQE of green LED structures is investigated numerically using a finite-difference time-domain simulation. The Purcell factor of flip-chip LED structures is found to be more than three times as high as that of epi-up LED structures, which is attributed to the high-reflectance mirror near the active region in the flip-chip LED structures. When the unmodified IQE is 20%, the relative enhancement of IQE can be greater than 50%, without utilizing the surface-plasmon coupling effect. Based on the simulation results, the "green gap" problem of GaN-based green LEDs is expected to be mitigated significantly by optimizing flip-chip LED structures to maximize the Purcell effect.

Reproduction and marketing plans for improving profitability of Korean native cattle (Hanwoo) farm (한우 농가 수익성 향상을 위한 번식 및 출하 계획)

  • Choi, Inchul;Cho, Jaesung
    • Journal of Embryo Transfer
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    • v.31 no.3
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    • pp.267-272
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    • 2016
  • Wholesale beef price is the critical factor for determining Korean native cattle, Hanwoo, farm's income in short-term. Wholesale beef price has seasonality due to high demand in Korean traditional holidays such as Korean thanksgiving day and lunar new year's day. Therefore, it is important to make reproduction and marketing plans for Korean Hanwoo farmers, in order to increase their farm income. However, there is no study available on changes in the expected farm income depending on reproduction and marketing schedules. This study analyzed the expected farm income per head depending on the monthly-based marketing schedules. The analysis was conducted based on the seasonality of wholesale beef price, reproduction efficiency, operating costs, relationship between carcass grade and slaughter age. The result shows that slaughter Hanwoo at the age of 29 months-old in August and January generating the highest expected farm income per head.

An Analysis on the Expected Performance of Constructing and Operating the Integrated Computing Environment in case of Culture Informatization (문화정보화 부문의 통합전산환경 구축.운영의 기대 성과분석)

  • Jung, Hae-Yong;Kim, Sang-Hoon
    • Journal of the Korea Society of Computer and Information
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    • v.11 no.1
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    • pp.203-222
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    • 2006
  • This study proposes the methodology of analyzing the expected performance of the Integrated Computing Environment(ICE) on the assumption that the ICE of the agencies and the affiliated organizations under Ministry of Culture and Tourism is constructed and operated. The main objectives of the study are as follows : 1) deriving the performance criteria divided into the operational expected value and the strategic expected value of constructing and operating the ICE for Culture and Tourism informatization, 2) proposing the ways of extracting the detailed criteria for four performance areas(the degree of jnformatization efficiency, the degree of public service, the innovation and development of IS organization, the culture and tourism value creation) to evaluate the operational expected value based on the BSC(Balanced Scorecard) Perspective by using the CSF(Critical Success Factors) methodology, and 3) developing the detailed performance criteria and measures for the economic evaluation of the informatization efficiency from the TCO(Total Cost of Ownership) perspective and suggesting the practical evaluation method by applying them to the case of Culture and Tourism informatization.

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Characteristics of Power Efficiency of Tractor Driveline (트랙터 전동라인의 전동효율 특성 분석)

  • 류일훈;김대철;김경욱
    • Journal of Biosystems Engineering
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    • v.27 no.1
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    • pp.19-24
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    • 2002
  • According to the field test, the transient power transmission efficiency of a tractor driveline fluctuated in a range of 56 to 86% and the mean value was about 72.5%. Therefore, the constant efficiency model commonly used for a simulation of power performance was not proper far predicting such a variable of efficiency. In order to predict power efficiency more accurately, new concepts of the maximum efficiency and drag torque were introduced and a new model based on the these concepts was proposed. The difference between measured and model-predicted efficiencies was about 1.5% in average with a standard deviation of 1.1%. The new power efficiency model was expected to enhance the accuracy of predicting power transmission efficiencies of tractor drivelines.

Asymptotic Relative Efficiency of t-test Following Transformations

  • Yeo, In-Kwon
    • Journal of the Korean Statistical Society
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    • v.26 no.4
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    • pp.467-476
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    • 1997
  • The two-sample t-test is not expected to be optimal when the two samples are not drawn from normal populations. According to Box and Cox (1964), the transformation is estimated to enhance the normality of the tranformed data. We investigate the asymptotic relative efficiency of the ordinary t-test versus t-test applied transformation introduced by Yeo and Johnson (1997) under Pitman local alternatives. The theoretical and simulation studies show that two-sample t-test using transformed date gives higher power than ordinary t-test for location-shift models.

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Improvement of Light Extraction Efficiency by Side Surface Texturing in Nitride-based Light-Emitting Diodes (질화계 발광다이오드의 측면 형상화를 이용한 광 추출 효율 향상)

  • Jang, Dong-Hyeon;Sim, Jong-In
    • Proceedings of the Optical Society of Korea Conference
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    • pp.95-96
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    • 2008
  • We theoretically investigated the influence of side surface texturing on the light extraction efficiency in nitride-based light-emitting diodes (LEDs). The light extraction efficiency was expected as 1.2 times larger in a LED with textured surfaces compared to without ones.

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Optimal Redundant Units and Load in Parallel Systems (병렬 시스템에서의 최적 중복부품수와 최적 부하수준)

  • 윤원영;김귀래
    • Journal of the Korean Operations Research and Management Science Society
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    • v.23 no.1
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    • pp.97-107
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    • 1998
  • This paper is concerned with a parallel system that sustains a time-independent load and consists of n components with exponential lifetimes. It is assumed that the total load is shared by the working components and the failures of components increase higher failure rates in the surviving components according to the relationship between the load and the fialure rates. The power rule model among several load-failure rate relationships is considered. We consider the system efficiency meausre as the expected profit earned by the system per unit time. The high load causes high gain but it also occurs frequent system failures. The expected profit per unit time is used as criterion to evaluate the system efficiency. The goal of system engineer is to determine the optimal load and redundant units maximizing the expected profit per unit time. First, the system reliability function is obtained and the optimization problem of the load-sharing parallel system is considered. Given the redundant units, the existence of the optimal load can be proved analytically and given the load, the optimal redundant units can be solved also analytically. The optimal load and redundant units are obtained simultaneously by numerical computation. Some numerical examples are studied.

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