• Title/Summary/Keyword: structure of stand

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Root Development end Branching farms of Norway Spruce(Picea abies) in the Differently Acidified Forest Soil (토양(土壤) 산성화(酸性化) 정도(程度)에 따른 독일가문비나무(Picea abies)의 뿌리 발달(發達)과 분지형태(分枝形態)에 관(關)한 연구(硏究))

  • Lee, Do-Hyung
    • Journal of Korean Society of Forest Science
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    • v.90 no.4
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    • pp.458-464
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    • 2001
  • In this study, the annual growth of roots and their branching forms of Norway spruce(Picea abies [L.] Karst.) were analysed to compare the development of their root in the differently acidified forest soils. And there was no significant difference among the stands for the modified roots and the non-modified roots depending on the root branch forms, and however in the most acidified Weidenbrunnen stand, the modified roots, the abnormal root branch form such as fork, gun and rake types were appeared. As a result of the ring of the root, the annual horizontal root growth were 6.3cm for Weidenbrunnen and Barbis stands and 9.5cm for Eberg$\ddot{o}$tzen stand. The average annual vertical root growth was 4.4cm, 5.4cm, and 6.7cm for Weidenbrunnen stand, Barbis stand, and Eberg$\ddot{o}$tzen stand, respectively. The cross section area by root distribution at 80cm deep showed that the thick and thin roots were evenly distributed in of Eberg$\ddot{o}$tzen stand and the sum of root cross section area was $32.6cm^2$. In Barbis stand, the thick roots were distributed in the center while the thin roots were comparatively rare. And the sum of root cross section area was $29.2cm^2$. In Weidenbrunnen stand, only a few thin roots were found, and the total root cross section area was $10.9cm^2$. The stability coefficient of roots were in the order of Eberg$\ddot{o}$tzen stand(1.04), Barbis stand (0.3), and Weidenbrunnen(0.08) stand. Among the investigated Norway spruce stands, the modified abnormal root branching form and the low root growth appeared in the Weidenbrunnen stand could be attributed by the soil acidification etc.

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Studies on the Productivity and the Production Structure of the Forests I. On the Productivity of Pinus rigida Plantation (삼림의 생산구조와 생산력에 대한 연구 I. 리기다소나무 조림지에 대하여)

  • 김준호
    • Journal of Plant Biology
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    • v.14 no.4
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    • pp.19-26
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    • 1971
  • The sample stand of Pinus rigida plantation was chosen from those at the Choongnam Forest Experiment Station, Choongnam. The diameter at breast height (D) and the height of tree (H) of each tree in the sample plot of 200$m^2$ were measured yearly a from 1967 through 1969. The stand was 12.7-13.4cm in mean diameter and had a stand density of 2,150 trees per ha. The trunk, branches and leaves of each sample tree were separately weighed according to the stratified clip technique. The allometric relation between D2H and dry weight of trunk (Ws), branches (Wb) and leaves (Wl) were approximated by $$W_s=0.05917 (D^2H)^{0.837}$$ $$W_0=0.00655 (D^2H)^{0.989 }$$ $$W_l=0.04466(D^2H)^{0.690}$$ From the above, the standing crops in the sample stand was estimated to be as much as 76.7, 81.7 and 88.2 tons of dry matter, above ground, per ha in 1967, 1968 and 1969, respectively. Annual net production, as the sum of the biomass newly produced during one year, was estimated at 4.97-5.47 tons per ha per year. The respiratory and the photosynthetic rate deduced from theoretical calculations were 0.045 and 0.74kg of dry matter per kg per year. Tentative estimate of annual respiratory loss was made and annual gross production was roughly estimated at 4.4-4.7 and 10.7-12.9 tons of dry matter per ha per year. The ratio of respiratory loss to gross production was approximately 36-41:1.

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The effect of hip joint strengthening exercise using proprioceptive neuromuscular facilitation on balance, sit to stand and walking ability in a person with traumatic brain injury: a case report

  • Jung, Du Kyo;Chung, Yijung
    • Physical Therapy Rehabilitation Science
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    • v.6 no.2
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    • pp.96-104
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    • 2017
  • Objective: The purpose of this study was to investigate the effect of the hip joint strengthening exercises using proprioceptive neuromuscular facilitation (PNF) on the clinical symptoms and the treatment effects in balance, sit to stand, and gait abilities in patients with TBI. Design: A single case study. Methods: A 13-year-old adolescent with quadriplegia and hip joint control impairment participated in this four-week training intervention. The patient, diagnosed with TBI, wastreated with hip joint strengthening exercises using PNF. In the first week, we focused on strengthening the body, relaxing the hip flexors and activating the hip extensor muscles in order to solve the patient's physical function and body structure. From the 2nd and 4th week, we improved the motivation through the task-oriented method, and then weight-bearing training of the right lower extremity was proceeded by kicking a soccor ball with the left lower extremity. The exercises were performed for 4 weeks, 5 days a week, for 60 minutes with the exercise intensity gradually increased according to the subject's physical abilities. Results: As a result of the study, the patient demonstrated improvements in the physical examination, which were evaluated before and after intervention and included the manual muscle test, modified Ashworth scale, sensory assessment, coordination assessment, Berg balance scale, 5-time sit to stand test, and the 10 meters walk test. Conclusions: The results of this case suggest that a hip joint strengthening exercise program using PNF may improve hip control ability, balance, sit to stand and gait ability in a patient with TBI.

Efficient Vibration Analysis of Stadium Structure (경기장 구조물의 효율적인 진동해석)

  • 김기철;이동근
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2001.10a
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    • pp.475-482
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    • 2001
  • Stadium stand could be led to significant dynamic response due to rhythmical activities of spectator. The dynamic loads induced by spectators movements are considered as static loads in design standard of many countries but these loads have dynamic characteristics. So, it is desirable to apply measured dynamic loads created by spectator activities and to analyze the dynamic behavior of stadium system. The precise investigation of the dynamic loads on stadium structures and the accurate analysis of dynamic behavior of stadium systems are demanded for effective design. As the floor mesh of stadium stand is refined, the number of nodes increase in numerical analysis. So it is difficult to analyze entire stadium structures and much more computer memory are necessary for vibration analysis of stadium system. In this study, the various dynamic loads induced by spectator movements are measured and analyzed. And new modeling method that reduce the nodal points of stadium systems are introduced. Vibration analysis of stadium system is executed to inspect the accuracy and the efficiency of proposed method in this paper.

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Aeroelastic investigation of a composite wind turbine blade

  • Rafiee, Roham;Fakoor, Mahdi
    • Wind and Structures
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    • v.17 no.6
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    • pp.671-680
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    • 2013
  • Static aeroelastic is investigated in a wind turbine blade. Imposed to different loadings, the very long and flexible structures of blades experience some changes in its preliminary geometry. This results in variations of aerodynamic loadings. An iterative approach is developed to study the interactions between structure and aerodynamics evaluating variations in induced stresses in presence of aeroelasticity phenomenon for a specific wind turbine blade. A 3D finite element model of the blade is constructed. Aerodynamic loading is applied to the model and deflected shape is extracted. Then, aerodynamic loadings are updated in accordance with the new geometry of the deflected blade. This process is repeated till the convergence is met. Different operational conditions consisting of stand-by, start-up, power production and normal shut-down events are investigated. It is revealed that stress components vary significantly in the event of power production at the rated wind speed; while it is less pronounced for the events of normal shut-down and stand-by.

Controller Design of Stand-Alone Photovoltaic System with Charge-Discharge Controller for Remote lsland Power Supply

  • Kang, Ki-Hwan;Yu, Gwon-Jong;Song, Jinsoo;Jeong, Young-Seok;Kang, Ki-Hwan;Lee, Byoung-Ku;Choe, Gyu-Ha
    • Proceedings of the KIPE Conference
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    • 1998.10a
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    • pp.972-977
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    • 1998
  • This paper deals with stand-alone Photovoltaic system(SPVS) with charge and discharge controller. Main power source of SPVS are generally solar cell and battery. Therefore SPVS can be classified into variable types in accordance with connection method between battery and solar cell array. Mainly used one of them is direct connection type which has advantages such as simple structure and simple controller. However most big drawback of this system is energy loss by voltage disharmony between solar cell array and battery. Therefore SPVS with charge and discharge controller which can operate solar cell array at maximum power point is designed and experimented with a laboratory prototype.

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Changes of Muscle Activity on Functional Movement according to Foot Type (발의 형태에 따른 기능적 움직임의 근활성 변화)

  • Chae, Jung-Byung;Moon, Ok-Yun
    • PNF and Movement
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    • v.9 no.4
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    • pp.41-48
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    • 2011
  • Purpose : The purpose of this study was to assess the tibialis anterior, soleus, gluteus maximus, transverse abdominis muscle activity of tibialis anterior, soleus, gluteus maximus, transverse abdominis according to pronated foot and supinated foot. Methods : Group of pronation and supination were taped using augmented low-day method to make pronated and supinated foot the three case were assessed by agnostic radiology for investigating foot structure. Results : 1) When supinated foot & pronated foot, tibialis anterior & gluteus maximus muscle activity was augmented in one step. 2) When supinated foot & pronated foot, soleus & transverse abdominis muscle activity was decreased in one step. 3) When supinated foot & pronated foot, tibialis anterior & gluteus maximus muscle activity was augmented in squat. 4) When supinated foot & pronated foot, soleus muscle activity was decreased in squat. 5) When pronated foot, transverse abdominis muscle activity was decreased in squat. 6) When supinated foot, transverse abdominis muscle activity was augmented in squat. 7) When pronated foot, transverse abdominis & gluteus maximus & tibialis anterior muscle activity was augmented in sit to stand. 8) When supinated foot, transverse abdominis & gluteus maximus & tibialis anterior muscle activity was decreased in sit to stand. 9) When supinated foot & pronated foot, soleus muscle activity was decreased in sit to stand. Conclusion : 1) Pronated foot & supinated foot effects on soleus, gluteus maximus, transverse abdominis muscle activity in one step. 2) Pronated foot & supinated foot effects on tibialis anterior, gluteus maximus, transverse abdominis muscle activity in squat. 3) Pronated foot & supinated foot effects on soleus, transverse abdominis muscle activity in sit to stand. Therefore we suggest the deformity of the foot effects on tibialis anterior, soleus, gluteus maximus, transverse abdominis muscle activity.

Individual-based Competition Analysis for Secondary Forest in Northeast China

  • Li, Fengri;Chen, Dongsheng;Lu, Jun
    • Journal of Korean Society of Forest Science
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    • v.97 no.5
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    • pp.501-507
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    • 2008
  • The data of crown width with 4 directions, DBH, tree height, and coordinate for sample trees were collected from 30 permanent sample plots in secondary fore st of the Maoershan Experimental Forestry Farm, Northeast China. In this paper, the competition of individual trees in stand were discussed for secondary forest by using iterative Hegyi competition index and crown overlap index that represented the competitive and cooperative interactions among neighboring trees. Active competitors of subject tree in the competition zone were selected to calculate the iterative competition index. Using the results of crown classification based on the equal crown projection area, a new distance dependent competition index called crown overlap index (COI) was developed for secondary forest. The COI performed well in describing the crown competition rather than crown competition factor (CCF). The individual-based competition index discussed in this paper will provide more precise for developing individual tree growth models for secondary forest and it can also use to adjust the stand structure for spatial optimal management.

Generation of DEM Data Under Forest Canopy Using Airborne Lidar

  • Woo Choong-Shik;Kim Tae-Guen;Shin Jung-Il;Lee Kyu-Sung
    • Proceedings of the KSRS Conference
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    • 2005.10a
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    • pp.512-514
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    • 2005
  • Accurate DEM surface of forest floor is very important to extract any meaningful information regarding forest stand structure, such as tree heights, stand density, crown morphology, and biomass. In airborne lidar data processing, DEM data of forest floor is mostly generated by interpolating those elevation points obtained from last laser returns. In this study, we try to analyze the property of the last laser return under relatively dense forest canopy. Airborne laser data were obtained over the study area in relatively dense pine plantation forest. Two DEM data were generated by using all the points in the last laser returns and using only those points after removing non-ground points. From the preliminary analysis on these DEM data, we found that more than half of points among the last laser returns are actually hit from canopy, branches, and understory vegetation that should be removed before generating the surface DEM data.

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A Study on Standing Crops of Seedlings and Sapling in Pinus rigida Forest (리기다소나무 임상에 있어서의 Seedling 및 Sapling의 현존량에 관한 연구)

  • 방재욱
    • Journal of Plant Biology
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    • v.22 no.3
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    • pp.59-62
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    • 1979
  • Distribution and standing crops of seedling and sapling as undergrowing tree were investigated in a Pinus rigida forest. The relative light intensity(RLI) on the ground level was 3.9∼59.3% which indicates a wide range. Under this range of RLI seedlings and saplings distribute well in the stand. Eight trees were selected from the stand, then measured dry weight of stem, branches and leaves using thestratified clip technique. A possible relationship between the diameter at the bottom of the tree (Do) and standing crops was investigated. As Do increased from 0.8cm (T1) to 7.2cm (T8), the standing crops also increased from 42.6g to 7,410.4g. Since semi-log values between Do and standing crops clearly indicates a straight line, there is close relationship between these two factors. Therefore it is possible to estimate the standing crops of seedling and sapling by measuring Do. Productive structure shows that phytosynthetic layer is located above the 1/2 height of the tree and maximum photosynthetic layer apperars on 2/3 level in height.

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