• 한국토양비료학회지
• /
• 제46권4호
• /
• pp.245-252
• /
• 2013

Leaf area index (LAI) is important in explaining the ability of crops to intercept solar energy for biomass production, amount of plant transpiration, and in understanding the impact of crop management practices on crop growth. This paper describes a procedure for estimating LAI as a function of image-derived vegetation indices from temporal series of RapidEye imagery obtained from 2010 to 2012 using empirical models in a rice plain in Seosan, Chungcheongnam-do. Rice plants were sampled every two weeks to investigate LAI, fresh and dry biomass from late May to early October. RapidEye images were taken from June to September every year and corrected geometrically and atmospherically to calculate normalized difference vegetation index (NDVI). Linear, exponential, and expolinear models were developed to relate temporal satellite NDVIs to measured LAI. The expolinear model provided more accurate results to predict LAI than linear or exponential models based on root mean square error. The LAI distribution was in strong agreement with the field measurements in terms of geographical variation and relative numerical values when RapidEye imagery was applied to expolinear model. The spatial trend of LAI corresponded with the variation in the vegetation growth condition.

• The Korean Journal of Ecology
• /
• 제9권3호
• /
• pp.123-133
• /
• 1986

Black pine, Pinus thumbergii, stands in southwestern Korea were investigated. The black pine forest with 90 percent or more in the relative basal area (black pine basal area/whole pine basal area, RBA) was found in the coastal area. However, from the coastal area to the inland. RBA of the pine was decreased because the competition with red pine (P. densiflora) and/or pitch pine (P. rigida). In 25 year-old plants at the coastal areas, the wood volume of black pine is twofold or more than that of red pine, fourfold or more than that of pitch pine. The optimum rotation period for the maximum yield of black pine is estimated to take 35 years, based on the site index calculated. The optimal temperature for the pine plantation in Korean peninula should be the area in over 105。C.month in warmth index. And the soil conditions with 50% of RBA or over were 0.025%~0.151% of soil salinity, 3~6% of organic matter content, pH value 4.50~5.04, 8.5~11.0 me/100g of C.E.C..

• ETRI Journal
• /
• 제45권4호
• /
• pp.636-649
• /
• 2023

Renewable energy generation cannot be consistently predicted or controlled. Therefore, it is currently not widely used in the electricity market, which requires dependable production. In this study, reliability- and variance-based controls of energy storage strategies are proposed to utilize renewable energy as a steady contributor to the electricity market. For reliability-based control, photovoltaic (PV) generation is assumed to be registered in the power generation plan. PV generation yields a reliable output using energy storage units to compensate for PV prediction errors. We also propose a runtime state-ofcharge management method for sustainable operations. With variance-based controls, changes in rapid power generation are limited through ramp rate control. This study introduces new reliability and variance indices as indicators for evaluating these strategies. The reliability index quantifies the degree to which the actual generation realizes the plan, and the variance index quantifies the degree of power change. The two strategies are verified based on simulations and experiments. The reliability index improved by 3.1 times on average over 21 days at a real power plant.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회B
• /
• pp.3045-3049
• /
• 2007

This paper presents a numerical study to enhance the mixing of polyurethane resin in a container. In general, the properties of polyurethane resin vary with the production environment, such as temperature. However in this study we assumed that the dynamic viscosity of the polyurethane is kept constant at 15 [Pa s]. We computed the flow solution and visualized the mixing pattern for different shapes of mixers by using commercial code, ANSYS CFX. In order to quantify mixing, we employed the concept of mixing index by volume integration.

• KDI Journal of Economic Policy
• /
• 제39권4호
• /
• pp.51-68
• /
• 2017

This paper adapts the World Bank Regulatory Quality Index (RQI), which is produced annually to provide a better understanding of the effects of regulatory reforms, instead of the Production Market Regulation (PMR) indicators, which are published every five years. We find that 9.9 to 36.0 billion USD worth of regulatory cost could be reduced if the regulatory quality in Korea improves to the level of the OECD average considering that the total burden of regulation in Korea is estimated to range from 2.2 to 357.4 billion USD. The estimated reduction in the regulatory cost accounts for roughly 0.76 to 2.47% of Korea's GDP in 2013, underscoring the importance of regulatory reforms for the Korean economy. This paper introduces a new method with which to examine the distribution of regulatory costs across different industries and firm sizes. This alternative method is largely consistent with the conclusions reached by other studies, specifically that small firms typically bear a disproportionate regulatory burden.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1990년도 추계학술대회 논문집 학회본부
• /
• pp.244-246
• /
• 1990

This paper describes the Large Deviation Method for computing the loss-of-load-probability (L.O.L.P.) index for a generating system. Also, we introduce a rule to prevent the initial value from diverging in Newton-Raphson method which we have to use to determine the value of t. By applying the Large Deviation Method to computing the L.O.L.P. index for some representative reliability test systems, it is verified that the Large Deviation Method is generally very accurate and very fast.

• 한국안전학회지
• /
• 제33권2호
• /
• pp.39-44
• /
• 2018

Dust explosions are occurring in a variety of industries. A dust explosion caused by a specific energy generates huge amount of energy in the ignition and releases decomposition gas. Damages can be increased since this released decomposition gas can cause second and subsequent explosions. In this study, the goal was to obtain practical information on what could affect the explosion by comparing the characteristics of two kinds of dusts with completely different chemical properties. Three kinds of dusts were measured and evaluated for explosion pressure, dust explosion index, explosion limit and minimum ignition energy. It is possible to grasp the characteristics of each dust and use it as useful accident prevention data in the production of raw material powder.

• 한국자동차공학회논문집
• /
• 제7권6호
• /
• pp.32-41
• /
• 1999

Natural gas is an attractive fuel in view of environment benefits due to its flow carbon-to-hydrogen ratio. However, its compositions and properties are varied depending upon production regional groups. Therefore, study on the combustion characteristics of natural gas engines with a variety of compositions has been demanded for the efficient application of gas engines. This study aims to investigate the effects of gas composition on engine combustion characteristics. It was found that , by controlling an engine with fixed fuel nozzle area, power and heat release were subject to Wobbe Index. And at fixed excess air ratios, power and heat release were subject to low heating value of unit mixture . In addition, in case of constant nozzle area, combustion duration was found to be inversely proportional to CP(Combustion Potential), and the condition of fixed excess air ratios showed no change in combustion duration, regardless of CP.

• 기술혁신학회지
• /
• 제4권3호
• /
• pp.369-382
• /
• 2001

In this research, the world top steel companies' technical changes were measured by the nonparametric Malmquist index. Steel industry's production frontier which was composed of multiple inputs and multiple outputs was defined by using real data of the companies from 1986 to 1998, and then the variability of technical progress(or regress) was analyzed during that period. The dynamics of individual steel companies\` technical changes, periodical technical changes, and each country's technical chanties were explained. A matrix which was based on technical chanties, technical efficiency changes, and scale efficiency changes was designed to assist to find out current position and In build up future strategies. This research results will be an valuable input to the early stage of formulating competitive strategy because the technical core capability is an important source of the each companies's competitiveness.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2005년도 ICCAS
• /
• pp.740-745
• /
• 2005

This study is intended to build a controller of redundant manipulators with the simultaneous abilities of trajectory tracking and obstacle avoidance without any preparations of path planning to achieve full automation even for one production of one kind, while keeping the avoidance ability high and keeping its shape away from object to reduce the possibility that the manipulator crashes to the object. To evaluate the avoidance ability of the intermediate link, we proposed a scalar value of Avoidance Manipulability Shape Index(AMSI), which is independent of the obstacle's shape. On the other hand, the danger to crash to the obstacle is depending on the shape of the obstacle, which could be evaluated by the potential field set around the obstacle. This paper proposes control method of the manipulator's shape based on the AMSI to simultaneously avoid obstacles and keep the avoidance ability high with potential.