• 한국산림과학회지
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• 제111권2호
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• pp.311-318
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• 2022

본 연구는 꿀샘식물인 아까시나무의 적지적수 조림을 위해 판정기준인 지위지수를 도출하고, 도출된 지위지수별 경급별 분포 변화를 알아보기 위하여 수행되었다. 아까시나무 임분의 지위지수를 추정하기 위하여 적용한 모델은 Chapman-Richards식이었다. 도출된 식에 따르면, 우리나라 아까시나무의 지위지수는 기준임령이 30년 일 때 16~22 범위 내에 분포하는 것으로 나타났다. 그리고 지위지수 추정 모델의 적합성은 약 37%정도로 낮았으나, 식의 잔차분포가 한쪽으로 치우지지 않아(bias -0.0030) 활용에는 문제가 없는 것으로 판단된다. 아까시나무 생장에 따른 지위별 직경분포를 구명하기 위해서는 Weibull 직경분포함수를 이용하였다. 직경의 분포를 나타내는 인자로 평균직경과 우세목 수고를 설명변수로 하였으며, 이들은 Weibull 직경분포함수의 모수를 추정하고 복구하는 단계를 거쳤다. 최종적으로는 아까시나무 임분의 평균직경과 우세목 수고로서 직경급별 분포를 나타낼 수 있었으며, 분포 추정에 대한 설명력은 약 80.5%인 것으로 나타났다. 지위지수별 직경분포를 30년생 기준으로 도식화한 결과, 지위지수가 높을수록 직경분포 곡선이 오른쪽으로 이동함을 알 수 있었다. 즉 적지적수를 고려하여 지위지수가 높은 곳에 조림한다면 아까시나무의 생장이 왕성해져 용재생산 뿐만아니라 꿀 생산도 많아질 것임을 유추할 수 있었다. 따라서 본 아까시나무 지위지수분류표와 곡선이 꿀샘식물인 아까시나무를 조성 및 관리함에 있어 의사결정의 기준이 되기를 기대한다.

• 한국작물학회지
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• 제64권2호
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• pp.159-164
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• 2019

Weed control is a crucial practice not only in organic farming, but also in modern agriculture because it can lead to loss in crop yield. In general, weed is distributed in patches heterogeneously in the field. These patches vary in size, shape, and density. Thus, it would be efficient if chemicals are sprayed on these patches rather than spraying uniformly in the field, which can pollute the environment and be cost prohibitive. In this sense, weed detection could be beneficial for sustainable agriculture. Studies have been conducted to detect weed patches in the field using remote sensing technologies, which can be classified into a method using image segmentation based on morphology and a method with vegetative indices based on the wavelength of light. In this study, the latter methodology has been used to detect the weed patches. As a result, it was found that the vegetative indices were easier to operate as it did not need any sophisticated algorithm for differentiating weeds from crop and soil as compared to the former method. Consequently, we demonstrated that the current method of using vegetative index is accurate enough to detect weed patches, and will be useful for farmers to control weeds with minimal use of chemicals and in a more precise manner.

• Journal of Ecology and Environment
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• 제46권2호
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• pp.111-125
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• 2022

Background: Zanthoxylum armatum is one of the 30 prioritized medicinal plants for economic development of Nepal with a high trade value. Understanding the ecology of individual species is important for conservation and cultivation purposes. However, relation of ecological factors on the distribution and populations of Z. armatum in Nepal remain unknown. To address this knowledge gap, an attempt has been made to study the population structure, distribution, and regeneration potentiality of Z. armatum. Vegetation sampling was conducted at six different localities of Salyan district along the elevation range of 1,000 m to 2,000 m. Results: Altogether 50 plant species belonging to 44 genera under 34 families were found to be associated with Z. armatum. Significantly higher species richness was found at Rim (1,400-1,700 m) and Chhatreshwori (1,800-2,000 m) and lower at Kupinde (1,600-1,800 m). The highest population density of Z. armatum was at Kupinde (1,600-1,800 m) with a total of 1,100 individuals/ha. and the lowest at Chhatreshwori (1,800-2,000 m) with 740 individuals/ha. Based on the A/F value (Whitford index), it can be said that Z. armatum has random distribution in the study area. The plants were categorized into seedlings, saplings and adults based on plant height and the status of natural regeneration category determined. The regeneration potentiality of Z. armatum in the study area was fair with the average seedlings and saplings densities of 150 and 100 individuals/ha. Respectively. A Shannon-Weinner index mean value of 2.8 was obtained suggesting high species diversity in the study area. Conclusions: The natural distribution and regeneration of Z. armatum is being affected in the recent years due to anthropogenic disturbances. Increasing market demand and unsustainable harvesting procedures are posing serious threat to Z. armatum. Thus, effective conservation and management initiatives are most important for conserving the natural population of Z. armatum in the study area.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.524-529
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• 2004

In this paper, We described the method which developed the optimal control system for air separation unit to change production rates frequently and rapidly. Control models of the process were developed from actual plant data using subspace identification method which is developed by many researchers in resent years. The model consist of a series connection of linear dynamic block and static nonlinear block (Wiener model). The model is controlled by model based predictive controller. In MPC the input is calculated by on-line optimization of a performance index based on predictions by the model, subject to possible constraints. To calculate the optimal the performance index, conditions are expressed by LMI(Linear Matrix Inequalities).In order to access at the Bailey DCS system, we applied the OPC server and developed the Client program. The OPC sever is a device which can access Bailey DCS system.The Client program is developed based on the Matlab language for easy calculation,data simulation and data logging. Using this program, we can apply the optimal input to the DCS system at real time.

• 한국물환경학회지
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• 제23권6호
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• pp.973-984
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• 2007

This study developed and calculated alternative evaluation index (AEI) from the effectiveness analyses of alternatives for rehabilitation of distorted hydrologic cycle. The feasible alternatives for the poor-conditioned region in the Anyangcheon watershed were proposed and quantitatively analyzed using continuous water quantity/quality simulation model, Hydrological Simulation Program-Fortran (HSPF). The effectiveness analyses include 355th flow and 275th flow of flow duration curve and number of increased days to satisfy the target monthly flow for water quantity and BOD average concentration, total daily loads and number of increased days to satisfy the target concentration and total daily loads. The feasible alternatives are restoration of covered stream, prevention of streamflow loss through sewers, redevelopment of existing reservoir, reuse of treated wastewater, use of groundwater collected by subway stations and construction of small wastewater treatment plant. Therefore, alternative priority ranking was derived from AEIs. It will be effective to make an integrated watershed management for sustainable development.

• 상하수도학회지
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• 제25권2호
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• pp.193-199
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• 2011

A method to improve internal corrosion control efficiency by adding lime and carbon dioxide, which, in turn increases the Langelier Index (LI) for filtered water at a conventional drinking water treatment plant (WTP) was investigated. The SJ WTP (Q=100,000 $m^{3}$/d) has been operating an internal corrosion control system since 2006. The system has achieved stable operation through technical development and trial and error over a period of several years. As a result of the operation, the LI of treated water has increased up to 29% by adjusting pH of filtered water to 7.8 with the addition of lime and carbon dioxide. Coupon tests in the distribution system indicated that the corrosion rate has been delayed by 24% when the internal corrosion method was implemented. The increase of LI by lime and carbon dioxide has been proven to be a practical method for controlling corrosion.

• Journal of the Optical Society of Korea
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• 제13권3호
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• pp.310-315
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• 2009

We report the fabrication of double clad fiber (DCF) and DCF coupler, suitable for fiber based imaging systems requiring the dual-channel transmission. Unlike the conventional DCF which uses silica for both cladding layers, the proposed DCF uses a low-index polymer for its outer-cladding layer coated over the conventional silica inner-cladding layer. The DCF is drawn with a conventional SMF preform but a low-index polymer coating is used for both jacket and outercladding of the fiber. To achieve the cladding mode coupling, a DCF coupler is fabricated by simply twisting two pieces of the proposed DCF after removing the polymer-coating at contacting regions. A cladding mode coupling ratio of 30% was achieved with a contact length of 16 cm. The proposed DCF and DCF coupler were employed in a composite optical coherence tomography (OCT) and fluorescence spectroscopy (FS) system, and both OCT images and FS signal from a plant tissue are measured simultaneously.

• Nuclear Engineering and Technology
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• 제54권4호
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• pp.1374-1381
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• 2022

Under the influence of nuclear radiation, the reliability of steam generators (SGs) is an important factor in the efficiency and safety of nuclear power plant (NPP) reactors. Motion planning that remotely manipulates an SG mobile tube-inspection robot to inspect SG heat transfer tubes is the mainstream trend of NPP robot development. To achieve motion planning, conditional traversal is usually used for base position optimization, and then the A^* algorithm is used for path planning. However, the proposed approach requires considerable processing time and has a single expansion during path planning and plan paths with many turns, which decreases the working speed of the robot. Therefore, to reduce the calculation time and improve the efficiency of motion planning, modifications such as the matrix method, improved parent node, turning cost, and improved expanded node were proposed in this study. We also present a comprehensive evaluation index to evaluate the performance of the improved algorithm. We validated the efficiency of the proposed method by planning on a tube sheet with square-type tube arrays and experimenting with Model SG.

• 한국환경생태학회지
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• 제35권3호
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• pp.294-304
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• 2021

본 연구는 지리산국립공원 심원계곡 생태경관 복원공사지역의 모니터링 결과를 분석하여 체계적인 복원관리를 도모할 수 있는 기초자료를 확보하는데 그 목적이 있다. 복원사업이 완료된 2017년도에 식생 모니터링을 위한 조사구 12개소와 대조구 4개소를 설치하였고, 2017년과 2020년의 상대우점치, 종다양도지수, 유사도 등의 변화를 분석하였다. 복원사업 시 수목이 식재되었던 조사구는 종다양도지수가 0~1.4552로 나타났고, 대조구와의 유사도지수에서는 1개 조사구가 1.32%로 분석된 것을 제외하고 모두 0%로 나타났다. 조사구의 종다양도지수 및 유사도지수가 매우 낮은 것은 복원사업 시 식재된 수목이 고사하거나 멧돼지 피해, 유수에 의한 침식으로 유실되는 등의 영향으로 판단되었다. 반면 복원사업 시 수목이 식재되지 않은 미식재 조사구는 종다양도지수가 0.9538~2.3222로 나타났고, 유사도지수는 최대 8.33%까지 분석되었다. 국립공원 생태경관 복원공사지역의 복원 공법 개발을 위한 장기 모니터링과, 미식재 조사구의 천이과정을 분석하는 지속적인 연구가 필요하다.

• 전기학회논문지
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• 제63권7호
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• pp.867-874
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• 2014

The pumped storage power plants have excellent load following characteristics. It can also be committed quickly for synchronous reserve when it is in the generating mode because it can readily increase its generating power and, consequently, increases the overall system reliability. There are strong incentives for standing the system reliability. Additionally, $CO_2$ emission can be typically impacted due to operation of pumped generators. The increase or decrease of $CO_2$ depends on the generation mix. This paper proposes evaluation of reliability, economy and environment of power system considering pumped generator. This paper describes three case studies of the reliability and economy and environment according to capacity factor and storage capacity of pumped generators. The probabilistic production simulation model is used in this paper. The practicality and effectiveness of the proposed approach are demonstrated by simulation studies for a real size power system model on the $5^{th}$ power plan in Korea.