• Journal of Korean Society of Forest Science
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• v.89 no.4
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• pp.502-512
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• 2000

Old-growth development for two different second-growth northern hardwood stands in the North America was evaluated with a computer simulation. The two sites compared were a representative 77 year old even-aged stand (Phelps) with heavy dominance by pole size classes, and an older uneven-aged stand with some existing old-growth structural features (Wildcat Creek). Each stand was evaluated in its natural progress toward old-growth structural conditions with stand structure, size distribution of live and dead trees, percent stand area in canopy gaps, and visual canopy profile and overhead view. The Phelps stand reached the minimum structural threshold for the old-growth stage after 74 years. Only 13 years was required for Wildcat Creek stand to reach the old-growth threshold. During the 45 years of simulation, the diameter distributions of both stands became broader and flatter. DBH distribution of dead trees had a general descending trend over the simulation in each stand. Gaps at Phelps were typically small after 45 years. Gap area at Wildcat Creek was somewhat more constant over the 45 years of simulation but a big gap was formed because of the death of several adjacent large trees.

• Journal of Korean Society of Forest Science
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• v.83 no.2
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• pp.155-163
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• 1994

This study was conduced to provide a method of tending practices for natural mixed stands, which have a possibility of inducing to selection cutting stand based on the analysis of stand structures. For this, first, diameter distribution for a balanced selection cutting stand was predicted using Q theory applied to natural stands. The method of estimating diminution ratio coefficient Q is presented. The possible tending practice method which could be adopted to natural stands is discussed based on two different diameter distributions and side conditions.

• Tunnel and Underground Space
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• v.10 no.4
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• pp.516-525
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• 2000

Recently, the demand for pollution-free demolition work of old reinforced concrete and steel structure has rapidly increased as the redevelopment of urban area has been accelerated. This study deals with linear shape charges for explosive jet cutting on steel structure. We have tested material and shape of steel structure, characteristics of thickness and strength, shape of linear shape charges, type of shape charges, cumulative charges, type of liner, stand-off distance, detonation method. effect of sound and vibration by air blast in explosive jet cutting method. So, We developed linear shape charges in order to take advantage of optimum explosive jet cutting condition. Shape charges were made of PETN explosives. We obtained the experimental formula to decide the amount of explosive needed for thickness of steel structure plate. There are prospects for application of the explosion curving technology under the open space conditions for dismantling the steel structure and steel bridge, scrapped old boats, which are going out of service.

• Journal of Forest and Environmental Science
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• v.16 no.1
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• pp.42-49
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• 2000

This study deals with the structure of Carabid beetle community surveyed in different stands. Species richness and abundance of Carabid beetles were 1,162 individuals, 23 species, 10 genera in the Pinus densiflora stand, 418 individuals, 23 species, 11 genera in the Pinus koraiensis stand, 782 individuals, 25 species, 11 genera in the Larix leptolepis stand, 1,383 individuals 25 species, 12 genera in the Quercus variabilis stand. Dominant species were Synuchus cycloderus(19.8%), Synuchus nitidus(16.6%), Pterostichus pertirax(16.2%) in the Pinus densiflora stand. Pterostichus sp.1(27.9%), Synuchus nitidus(24.4%), Synuchus cycloderus(10.2%) in the Pinus koraiensis stand, Synuchus sp.1(40.0%), Synuchus nitidus(9.3), Pterostichus sp.1(7.4%) in the Larix leptoepis stand. Pterostichus sp.2(17.4%), Synuchus cycloderus(14.4%). Pterostichus pertirax(14.1%) in the Quercus variabili stand. Shannon species diversity index(H') in the Pinus densiflora, Pinus koraiensis, Larix leptolepis and Quercus variabilis stand were 2.11, 2.25, 2.23 and 2.32 respectively and Evenness index(J') were 0.64, 0.72, 0.69 and 0.72, respectively. Community similarity index showed the lowest value (0.66) between Quercus variabilis stand and Pinus koraiensis stand and the highest value (0.83) between Pinus densiflora stand and Larix leptolepis stand.

• Journal of Forest and Environmental Science
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• v.20 no.1
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• pp.58-68
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• 2004

In this study, the stand structure of the Korean White Pine stand is analysed by the changing growth situation and the growth model for DBH, Height, and Volume per ha, which is estimated with the data collected for Korean White Pine stand in the Research Forests of Kangwon National University. The results were summarized as follows The estimated equations were (1) Y=20.687Ln(X)-50.431 for DBH, (2) Y=12.951Ln(X)-31.225 for Height, (3) Y=171.06Ln(X)-462.16 for Volume per ha. The mean volumes per ha according to the age classes using the estimated equations were $27.45m^3$ $91.05m^3$, $147.71m^3$, $190.03m^3$, $223.84m^3$, $252.01m^3$ and $276.15m^3$ for the age class II, III, IV, V, VI, VII and VIII, respectively. And also, the relationship between mean annual increment(MAI) and periodic average increment(PAI) was analysed.

• Journal of Korean Society of Forest Science
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• v.89 no.5
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• pp.677-684
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• 2000

This study was conducted to investigate the relationship of development of root and soil condition and also to elucidate the difference between stands for mechanical and physical stability according to distribution of roots in the Norway Spruce (Picea abies [L.] Karst.) stands of 30 to 40 year of ages with different soil condition. In the root structure, remarkably different root pattern was shown among the three stands; Eberg$\ddot{o}$tzen stand showed large number f roots with much fine roots which deeply in vertical direction while Barbis stands had thicker root and small number of root than Eberg$\ddot{o}$tzen stand. The Weidenbrunnen stand showed differently half-vertical and plate root structure and the root developed not to be deeply compared to the other two stands. In the total number of root, Eberg$\ddot{o}$tzen stand had the most number of 74 and Barbis stand 33, Weidenbrunnen stand 57 respectively. Eberg$\ddot{o}$tzen stand had much more number of vertical root with 57 than the other two stand; Barbis 21 and Weidenbrunnen 36. In the total length of root, Weidenbrunnen stand showed to be longer than the other two stands and the length of horizontal root also showed longer. Regarding to the rates of horizontal root against vertical root, Eberg$\ddot{o}$tzen stand showed comparatively higher value as 1,2 than other two stands(0.5). In the total weight of root, Weidenbrunnen stand showed very high value compared with the other stands and ratio of vertical root against horizontal root was 0,16 which is very lower than the other two stands(0,4). The remarkable differences of root pattern of Norway spruce stands appeared in this study are through to be caused more by chemical property of soil such as acidity den the mechanical or physical factor of soil conditions.

• Journal of Navigation and Port Research
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• v.35 no.8
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• pp.637-641
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• 2011

Ocean structure's power system is difficult to construct a stand-alone power system. Therefore, to manage effectively power system of ocean structure, it's important to construct power system which is connected fuel-cell with hybrid power system. This paper designs power system of fuel-cell for the sea based on hydrogen generation mechanism, calculation of using electric power, etc. Designed power system is analysed & simulated using LabVIEW program. And, this paper suggests design method of power system for ocean structure based on analysed & simulated results.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1495-1499
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• 2003

There is some equipment that helps user to exercise and to walk. But almost all equipments require some physical strength of their muscles. So we developed a system that could assist walking action of the people with lower-limb disability. The system called as walking stand adopted the balancing mechanism which assures the stable walking, and the 4 link-based mechanism that had 2 degrees of freedom on each leg. The walking stand uses four motors and has two sets of the special link-structure to simulate the human walking mechanism. With our system, even serious disabled with lower-limb disability may enjoy walking rehabilitation. And by adjusting the power, it can be used as the walking assistant mechanism instead of conventional wheelchairs. Experiments showed that our walking stand is applicable to the rehabilitation and also to the mobile device in our daily life for those people who do not have enough physical ability to walk by themselves.

• Journal of Institute of Control, Robotics and Systems
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• v.2 no.3
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• pp.134-141
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• 1996

In this paper, we formulate the mathematical model for a single-stand rolling mill and design control systems for the thickness control at the exit of roll stand and for the tension control of the strip in the process. We propose a thickness controller based on the Internal Model Control structure which can be an effective application when the frequency components of the thickness deviation of the entry strip are known and, show how it can be appropriately combined with BISRA AGC method for a precise thickness control while maintaining the robustness against the modeling error of the mill modulus. It is illustrated by simulations that the proposed thickness control method gives better performance than existing methods and has the robustness against the modeling error of the mill modulus as well.

• Korean Journal of Environmental Biology
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• v.25 no.2
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• pp.158-167
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• 2007

A study conducted in NaeSorak Mt. from 1996 to 2006 shows some interesting results indicating general characteristics of natural forests, regeneration and structural patterns on fir stands. Those fir stands could have been confused as climax forests, which is a short-sighted from human-centered view on those stands. A classic theory of succession, which has been frequently applied to analyse the changes in forest ecosystem changes, failed to provide further understanding of fir stands. To comprehend the complicated and diverse process, a concept of ecosystem circulation need be introduced to the theory. This is a main idea of 'patch dynamics' theory developed from 'mosaic cycle' theory.