• Korean Journal of Environment and Ecology
• /
• v.21 no.6
• /
• pp.554-558
• /
• 2007

Current biomass stock of forest has been calculated by using biomass expansion factors (BEFs) that convert timber volumes to dry weight and stem density. The objective of this study was to estimate stem density values and to develop BEFs that are dependent on tree age classes for Quercus acuta stands in Jeonnam Wando-gun. Sample trees on the three different age classes were harvested to obtain each components biomass with stem analysis. Stem density values as tree age classes were ranged from 0.557 to 0.636. Aboveground BEFs were ranged from 1.168 to 1.324. BEFs were increased with increasing age classes. There was a significant difference between BEFs and stem density values with tree age classes. These results suggest that the reliability of the national carbon stock inventory could be improved by applying age classes BEFs, which are formulated on the basis of representative for Quercus acuta.

• Korean Journal of Microbiology
• /
• v.42 no.1
• /
• pp.62-66
• /
• 2006

To study the packaging mechanism of the bacteriophage P2-P4 system which is a useful experimental tool for the study of viral capsid assembly, we analyzed the DNA contents of P4 sid- mutant, P4 ash8 sid71's phage particles. Two kind of particles having different density were separated by the CsCl buoyant equilibrium density gradient experiment with fresh made stock of P4 ash8 sid71. The DNA from each particles was prepared and its conformations was analyzed by electrophoresis. Unexpectedly, both particles contain not only dimeric and trimeric but also monomeric P4 DNA.

• Journal of Forest and Environmental Science
• /
• v.34 no.5
• /
• pp.412-417
• /
• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.547-552
• /
• 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.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.138-143
• /
• 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
• /
• v.34 no.1
• /
• pp.1-11
• /
• 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.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.12
• /
• pp.558-569
• /
• 2020

This study examined the frequency of a broiler's stay in each area as stock density using an ICT-based image analysis technique from the perspective of precision livestock farming (PLF) according to the increase in the domestic broiler farms to understand the normal behavior patterns of broilers by age. The broiler was used in the experimental box (3.3×2.7 m) in a poultry house in Gyeonggi province. The stock densities were 9.5 birds/㎡ (n=85) and 19 birds/㎡ (n=170), respectively, and the frequency of stay by feeding, water, and rest area was monitored using a top-view camera. The image data of three-colored-specific broilers identified as the stock density were acquired by age (12, 16, 22, 27, and 29 days) for six hours. In the collected image data, the object tracking technique was used to record the cumulative movement path by connecting approximately 640,000 frames at 30 fps to quantify the frequency of stay in each area. In each stock density, it was significant in the order of the rest area, feeding, and water area (p<0.001). In 9.5 birds/㎡, it was at 57.9, 24.2, and 17.9 %, and 73.2, 16.8, and 10 % in 19 birds/㎡. The frequency of a broiler's stay could be evaluated in each area as the stock density using an ICT-based image analysis technique that minimizes stress. This method is expected to be used to provide basic material for developing an ICT-based management system through real-time monitoring.

• Journal of Korean Institute of Industrial Engineers
• /
• v.3 no.1
• /
• pp.39-47
• /
• 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.

• Proceedings of the KSR Conference
• /
• 2003.05a
• /
• pp.604-609
• /
• 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

• Journal of Aquaculture
• /
• v.11 no.1
• /
• pp.91-97
• /
• 1998

This paper introduces to a simple culture method and growth of axenic (bacteria-free) rotifer Brachionus rotundiformis for seed stock of rotifer mass culture. This rotifer axenic culture method is based on the washing and transferring with sterilized sea water and modified antibiotic mixture AM9 solution. Population growth (final density on day 16) of axenic cultured rotifer were maintained with a high density and stable growth compared with the control of non-axenic culture (general culture style) through the 3 times-rerunning experiments (trial 1, 2 and 3). But the egg carrying rates of amictic females were not different between the axenic-and non-axenic culture condition. Although, rotifer density was higher in axenic culture, the food (Nannochloropsis oculata) was still remained unutilized than that of the non-axenic culture in third trial culture. These results suggest the possible existence of harmful bacteria for the rotifer population growth in the trial 1 and 3 of non-axenic culture compared to the trial 2. This axenic rotifer culture method is valuable for seed stock of the stable rotifer mass cultures.