• 한국환경생태학회지
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• 제21권6호
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• pp.554-558
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• 2007

산림의 현존량 축적에 대한 연구는 줄기밀도와 임목의 재적과 건중량을 전환하는 현존량 확장계수를 이용하여 추정한다. 본 연구의 목적은 전라남도 완도군 붉가시나무 임분의 줄기밀도와 영급에 따른 현존량 확장계수를 추정하기 위하여 수행되었다. 이를 위하여 각 영급별로 수간석해를 실시하여 각 부위별 현존량을 분석하였다. 분석결과 임목의 영급에 따른 줄기 밀도의 값은 $0.557{\sim}0.636$으로 나타났으며, 지상부 현존량 확장계수는 $1.168{\sim}1.324$였다. 지상부 현존량 확장계수는 수령이 증가할수록 값이 증가하였으며, 현존량 확장계수와 줄기 밀도는 임목의 영급에 따라 유의적인 차이가 있는 것으로 조사되었다. 이러한 결과들은 붉가시나무에 대한 전국 규모의 탄소고정량 산출에 있어서 영급에 따른 확장계수 추정의 기초 자료로 이용될 수 있을 것으로 사료된다.

• 미생물학회지
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• 제42권1호
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• pp.62-66
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• 2006

바이러스 조립 과정 기작 연구를 위한 좋은 재료인 박테리오파아지 P2-P4 시스템의 packaging 기작 연구를 위해, 머리 크기 조절 유전자 변이체인 P4 ash8 sid7l의 파아지 입자가 함유하고 있는DNA의 형태를 분식하였다. 파아지 stock을 준비하고 이것의 CsCl부양균등 밀도 편차실험을 수행하여, 밀도가 다른 두개의 입자들로 분리하였다. 각 입자의 DNA를 분리한 후, 전기영동을 통해 함유된 DNA의 형태를 확인하였다. 예상과 달리, 각 입자들은 dimer, trimer 뿐 아니라 monomer도 함유하고 있다는 새로운 사실을 발견하였다.

• Journal of Forest and Environmental Science
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• 제34권5호
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• pp.412-417
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• 2018

Agroforestry is emerged as climate smart agriculture system and known to help in maintaining soil nutrient sustainability but its rate of expansion is still not appreciable. The present paper incorporates the different species under various agroforestry practices its density, growth and growing stock. The most dominated agroforestry practices in Bilaspur district identified as boundary tree based agri- silviculture (32%) followed with inside field tree based agri-silviculture (21%). Agri-horti-silvicultural system found merely in 5% farmer's field while silvo-pastoral practice in 8% fields. The result depicts that the most prevailing agroforestry tree species in non-forest area of Bilaspur comprises Acacia nilotica 36%, Butea monosperma 22%, Albizia spp 16%, Terminalia arjuna 7%, Azadirachta indica 3.5% and other species 15.5%. More than 90% farmer allows tree species growing naturally in their fields mainly for fuel wood, timber and as source of additional income as these species need not require special attention and care, while only 5% farmer's has adopted Tectona grandis, Dalbergia sissoo etc commercially for higher future return. The paper also discusses the constraints on agroforestry for enabling development of agroforestry in future.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.547-552
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• 2003

In mold machining, there are many concave machining regions where chatter and tool deflection occur since MRR (material removal rate) increases as curvature increases even though cutting speed and depth of cut are constant. Boolean operation between stock and tool model is widely used to compute MRR in NC milling simulation. In finish cutting, the side step is reduced to about 0.3mm and tool path length is sometimes over 300m. so Boolean operation takes long computation time and includes much error if the resolution of stock and tool model is larger than the side step. In this paper, curvature of CL(cutter location) surface and side step of tool path is used to compute the feedrate for constant MRR machining. The data structure of CL surface is Z-map generated from NC tool path. The algorithm to get local curvature from discrete data was developed and applied to compute local curvature of CL surface. The side step of tool path was computed by point density map which includes cutter location point density at each grid element. The feedrate computed from curvature and side step is inserted to new tool path to regulate MRR. The resultants wire applied to feedrate optimization system which generates new tool path with feedrate from NC codes for finish cutting. The system was applied to speaker mold machining. The finishing time was reduced to 12.6%. tool wear was reduced from 2mm to 1.1mm and chatter marks and over cut on corner were removed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.138-143
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• 2007

The leading-cab (high energy absorption area) of rolling stock directly is impacted on the frontal crash unlike other cabs. Thus, leading-cab has a structurally complex shape to solve getting concentrated loads. However, in order to enhance structural performance and to achieve the weight reduction of cab, changing the sizes and adjusting the distance of members do not take an effective result. Therefore, in design phase, to find the material arrangement which helps structural capacity be better should be done. This research applies the topology optimization to concept design of protective shell frame on strategy of crush energy absorption with considering pressure and vertical loads acting on the principal part of leading-cab. In this research, topology optimization method focuses on structural design, and which yields optimal material arrangement under given loads and boundary conditions using density method which has the density of material as design variables. Finally, this research presents optimal material arrangement and structure of protective shell frame on given loads with applying topology optimization.

• Journal of Forest and Environmental Science
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• 제34권1호
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• pp.1-11
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• 2018

We studied natural and plantation forest ecosystem of Sarguja in Chhattisgarh, India in order to understand how vegetation biomass, carbon stock and its allocation patterns vary among the sites. For this, stratified random sampling was opted to measure the different layers of vegetation. Wide floral diversity was found in the natural forest site as compared to the teak stand. Overall, 17 tree species found in natural forest comprising 8 families while in the teak stand 6 species were recorded. In understory strata 23 species were recorded (18 herbs and 5 shrubs) in natural forest whereas in teak stand 20 herb species and 3 shrubs were found. Great variation was also seen in the population dynamics of the different vegetation stratum in concerned sites. The sapling, seedling and herb density was found to be highest in natural stand while tree and shrub density was more in teak stand. Results indicated that stand biomass of the natural site was $321.19t\;ha^{-1}$ while in the teak stand it was $276.61t\;ha^{-1}$. The total biomass of tree layer in plantation site was $245.22t\;ha^{-1}$ and natural forest $241.44t\;ha^{-1}$. The sapling, seedling, shrub and forest floor biomass was found highest under natural forest as compared to the teak plantation site. Carbon stock has similar trend as that of biomass accumulation in natural forest and teak stand. Higher biomass accumulation and carbon stock were recorded in the higher girth class gradation of the population structure. Proper efforts are required to manage these diverse ecosystems to obtain higher biomass and sustainable ecological services.

• 한국산학기술학회논문지
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• 제21권12호
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• pp.558-569
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• 2020

본 연구는 국내 육계농가의 사육규모 대형화에 따라 정밀축산(PLF)의 관점에서 ICT기반 영상분석기법을 활용하여 사육밀도에 따른 육계의 영역별 머무는 빈도(%)에 대해 평가하고, 일령별 육계의 정상적인 행동패턴을 이해하고자 수행하였다. 경기도 소재 육계농장 내 설치된 시험계사(3.3×2.7 m)에서 Ross308 육계를 공시축으로 이용하였다. 사육 밀도는 각각 9.5 수/㎡ (n=85), 19 수/㎡ (n=170)로 하였으며, 탑뷰(top view) 카메라를 이용해 급이·급수 및 휴식공간 영역별 머무는 빈도(%)를 모니터링 하였다. 사육밀도에 따라 개체 식별된 육계 3수에 대해 일령별(12, 16, 22, 27, 및 29일)로 6시간씩 영상이미지 데이터를 획득하였다. 수집된 영상데이터는 물체 추적(object tracking) 기법으로 초당 30프레임으로 약 64만장의 프레임을 연결하여 누적 이동경로를 기록하여 영역별 머무는 빈도(%)를 수치화하였다. 각 사육밀도에서 영역별 머무는 빈도(%)는 휴식공간, 급이영역, 급수영역 순으로 유의적인 차이를 나타내었다(p<0.001). 사육밀도(9.5 수/㎡)에서는 57.9, 24.2, 17.9%으로 나타났으며, 사육밀도(19 수/㎡)에서는 73.2, 16.8, 10.0%로 나타났다. 결과적으로 ICT기반 영상분석기법을 활용해 육계의 스트레스를 최소화하는 방법으로 사육밀도에 따른 육계의 영역별 머무는 빈도(%)를 평가할 수 있으며, 향후 본 연구결과는 실시간 모니터링을 통한 ICT기반 사양관리 시스템을 개발하는데 기초자료로 활용될 수 있을 것으로 기대된다.

• 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.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.604-609
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• 2003

The fire precautions regulation for Rolling stock in England, France and America concentrate on ensuring of safety in respect of material choosing method and consideration of design. In order to guarantee fire safety in Korean Rolling stocks, it is necessary to establish the fire precautions regulation at the two respects. Korean Standard of product classifies only incombustibility or not. It is not sufficient to classify various materials by testing method for incombustibility of material. Korean Standard to be reserved should be able to cover the smoke density test for small size and classification of the detail grade of material against the reaction to fire

• 한국양식학회지
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• 제11권1호
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• pp.91-97
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• 1998

이 연구에서는 해산어의 종묘 생산에 필요한 대량 배양용 로티퍼, Brachionus rotundiformis의 종 보존 방법으로서 무균 로티퍼의 이용을 검토했다. 로티퍼는 개량형 항생제 혼합액 AM9을 사용하여 무균 처리한후, 무균 Nannochloropsis oculata를 먹이로 공급하여 연속 유지 배양했다. 각각 다른 시기의 3회 (trial 1, 2 and 3)에 걸친 로티퍼 배양결과, 무균 배양 (axenic culture)에서는 비교적 안정적인 증식을 보인 반면, 유균 배양 (non-axenic culture)에서 로티퍼의 증식은 불안정적으로 각 시기에 따라서 심한 증식의 차이가 관찰되었다. 이 결과는 유균 배양에서 로티퍼의 증식에 직접적으로 악영향을 미치는 박테리아가 무균 처리과정을 통해서 제거되었음을 증명한다. 로티퍼 무균 배양 방법의 일반화 또는 대량 배양용 로티퍼의 씨앗으로서의 무균 로티퍼의 이용은 로티퍼의 안정 배양은 물론 유용 수산 생물의 대량 폐사를 일으키는 원인 생물을 사전에 제거할 수 있는 유효한 방법이 될 수 있다고 생각된다.