• Journal of Forest and Environmental Science
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• v.34 no.3
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• pp.235-241
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• 2018

This study was conducted to find out the growth pattern of Pinus koraiensis plantation over 34 years, focusing on DBH, height, basal area and allometric change. Total increment (TI), mean annual increment (MAI) and correlation coefficient were calculated and compared with stand and dominants. Total increment and mean annual increment of both DBH and height of dominants were bigger than those of stand. The difference was apparently shown bigger in DBH than height. Unlike DBH and height the total increment and mean annual increment of basal area per hectare of dominants were distinctively smaller than those of stand. Furthermore MAI of dominant was increasing until age 42, while MAI of stand increased at early ages and then gradually decreased after culmination like MAIs of DBH and height. MAIs of basal area of dead trees at each measurement tended to increase until early age (18 years in this study), while it reached a peak and gradually decrease after that (21 years in this study). Correlation coefficient between DBH and height tended to decrease as both dominant and stand age and the difference between dominant and stand was not clearly shown over the measurement period. Correlation coefficients between DBH and crown width tended to decrease as the trees age and correlation coefficients of dominant were clearly shown smaller than that of stand. Correlation coefficients of height and crown width also was found to be similar to correlation coefficients between DBH and crown. Meanwhile correlation coefficient of height and crown width dropped more radically than coefficient of DBH and crown width as the trees age.

• Korean Journal of Agricultural Science
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• v.4 no.1
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• pp.88-93
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• 1977

The following is the result of experiment on consolidation test under various load increment ratios by alternation of standard load increment ratio. The more load increment ratio was, the more settlement was resulted. But expansions were not associated with load increment ratios. Primary consolidation took longer period to complete as load increment ratio was decreased. And under the condition of over-consolidated range, the completion of primary consolidation took longer period as the load was incremented. Under the condition of normal consolidated range, there was no change in time of completing primary consolidation. The coefficient of consolidation was decreased with increment of consolidation load, and the coefficient of consolidation had high values as the load increment ratio was increased. The values of ratio of secondary consolidation was highest near the transition point of consolidation curve.

• Journal of Ocean Engineering and Technology
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• v.25 no.2
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• pp.120-126
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• 2011

The fatigue damages in structural details of offshore plants can be accumulated due to various environmental loadings such as swell, wave, wind and current. It is known that load histories acting on mooring and riser systems show stationary and ergodic bimodal wide-banded process. This paper provides refined approach to obtain time signals representing stress range histories from wide-banded bimodal spectrum which consists of ideally narrow-banded and fully separated two spectrums. Variations of the probabilistic characteristics for time signals according to frequency and sampling time increments are compared with the reference data to be the probabilistic characteristics such as zero-crossing period, peak period, and irregularity factor obtained from an assumed ideal spectrum. It is proved that the sampling time increment more affects on the probabilistic characteristics than frequency increment. The fatigue damages according to the frequency and sampling time increments are also compared with the ones with minimum increment condition which are thought to be exact fatigue damage. It is concluded that the maximum sampling time increment to obtain reliable time signals should be determined that ratio of applied maximum sampling time increment and minimum period is less than approximately 0.08.

• Journal of Korean Society of Forest Science
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• v.60 no.1
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• pp.24-29
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• 1983

This study was carried out to compare the diameter increment of seven major selected tree species which grow wild in middle area of Korea. The results obtained were summarized as follows. 1) The difference in annual diameter increment among seven species according to D.B.H. classes showed to be the strongest in Juglang mandshurica, the second rank Corpus controversa, the third rank Betula platyphylla, the fourth rank Tilia amurensis, the second rank Fraxinus mendshurica, the sixth rank Populus davidiana, and the weakest in Ulmus davidiana. 2) Total diameter increment among seven species according to tree age classes were ranked as follows: Juglans mandshurica, Cornus controversa, Betula platyphylla, Tilia amurensis, Fraxinus mandshurica, Populus davidiana, and Ulmus davidiana. 3) Juglans mandshurica showed the highest diameter increment in comparison with other six species, while diameter increment in Ulmus davidiana and Populus davidiana decreased in earlier age than other species.

• Journal of Korean Society of Forest Science
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• v.18 no.1
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• pp.9-12
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• 1973

Volume increment and estimation of future growth of pitch pine stand at age of 16 were analyzed based on the stand table method. The diameter growth survey was made by the Meyer's Increment Borer method which was based on the volume formular made on the single tree volume. The formular is V=0.000058D $^{1.6}{\times}H^{1.1}$ This survey was made based on the 95% reliability surveyed on the 339 trees in the 0.33ha of sample plot espicially set up. (1) Linear regression over annual diameter growth for the diameter is as follows; y=0.1618+0.0298x (2) Ninety percent of the total trees, in the diameter distribution of 2cm round off, each increased one step in diameter. (3) Stand volume increment percentage shows 16%. (4) The increment of stand volume for 5 years shows 46% of increment rate.

• Korean Journal of Agricultural Science
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• v.14 no.2
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• pp.329-344
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• 1987

This paper described the behavior under repeated loading in triaxial compression test on clay. The experiment was conducted to investigate the influence of controlled various over-consolidation ratio and compaction energy, on the stress-strain behavior of clays. 1. The difference of deviator stress during repeated loading was greatly appeared at large strain. And pore water pressure was decreased at initial of unloading, but it was increased again before long. 2. The recoverable elastic strain (${{\Delta}{\varepsilon}e}$) and the slope of un-reloading were decreased with the increment of over-consolidation ratio (OCR). 3. The recoverable elastic strain (${{\Delta}{\varepsilon}e}$) was increased with the increment of strain rate but it was decreased with the increment of strain in strain rate tests. The slope of un-reloading (Eur) tends to increase with the increment of strain rate and it was decreased with the increment of strain. 4. The recoverable elastic strain was greatly increased with the increment of compaction energy and it slightly tends to decrease with the increment of strain on various compaction energy. The slope of un-reloading was not appeared markedly with increment of compaction energy but it tends to decrease with the increment of strain generally.

• Journal of Korean Society of Forest Science
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• v.89 no.3
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• pp.414-421
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• 2000

This study was carried out for the artificial forest stand of 23 years old jack pine(Pinus banksiana Lamb.) in Soheul-myun, Pochun-kun, Kyunggi province of Korea. The objectives of this study were to investigate the stand volume increment and the rate of stand volume, and were to investigate present stand volume to determine annual cutting volume for keeping stand volume to an ideal level for investigated jack pine stand. For a reasonable calculation of stand volume increment, diameter of breast height(DBH), tree height, bark width, and core length for the last 10 years for respective sampling plots were measured. By using these measurements annual diameter increment in DBH class, stand volume increment of 95% confidence interval and tree height curve equation were calculated. The tree height value was derived from the tree height curve equation. Calculation of tree volume by using the tree volume table was made by conferring the tree height value. The summarized results for investigated jack pine trees were having 7.7% annual stand volume increment with 6.1% estimated error. The total stand volume per ha was $79.58m^3$, accordingly the annual stand volume increment was $6.13m^3$ per ha, and the 95% confidence intervals range from 5.77 to $6.51m^3$.

• Journal of Korean Society of Forest Science
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• v.99 no.5
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• pp.682-685
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• 2010

Coring has been widely used to measure annual increment in temperate forest ecosystems. This method is attractive because cores can be taken in just one visit. However, the accuracy of this method has not been tested. We expected coring to be less accurate than band dendrometers because of the eccentricity of tree growth. We studied 41 trees at the Long Term Experimental Forest in Mt. Gyebang, which has been monitored with band dendrometers since 1996. We collected two tree cores from the south and north face of each tree, 10 cm below the growth band. Increment cores were measured to 0.01 mm under stereomicroscopy. Annual growth from 1997 to 2006 was 3.2 mm $yr^{-1}$ for Quercus mongolica, 3.5 mm $yr^{-1}$ for Kalopanax septemlobus, and 5.7 mm $yr^{-1}$ for Pinus densiflora. The difference between the two methods was 10% for Q. mongolica, 14% for K. septemlobus, and 4% for P. densiflora. Compaction in the corer and shrinkage during drying decreased diameter increment by 5.6% and 1.0% on P. densiflora, respectively. This study suggests that the two methods for annual increment measurement are very similar, but species specificity should be concerned for direct comparison.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.349-352
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• 2006

The plastic deformation of polycrystalline materials is induced by changes of the microstructure when the loading is beyond the critical state of stress. Constitutive models for the crystal plasticity have the common objective which relates microscopic single crystals in the crystallographic texture to the macroscopic continuum point. In this paper, a new consistent tangent stiffness for the anisotropic elasto-viscoplastic analysis of polycrystalline deformation is developed, which can be used in the finite element analysis for the slip-dominated large deformation of polycrystalline materials. In order to calculate the consistent tangent stiffness, the state function is defined based on the consistency condition between the elastic and plastic stress. The rate of shearing increment($\Delta{\gamma}^{\alpha}$) is calculated with satisfying the consistency condition. The consistency condition becomes zero when the trial resolved shear stress($\tau^{{\alpha}^*}$) becomes resolved shear stress($\tau^{\alpha}$) at every step. Iterative method is utilized to calculate the rate of shearing increment based on the implicit backward Euler method. The consistent tangent stiffness can be formulated by differentiating the rate of shearing increment with total strain increment after the instant rate of shearing increment converges. The proposed tangent stiffness is applied to the ABAQUS/Standard by implementing in the ABAQUS/UMAT.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.5
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• pp.509-516
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• 2014

This study describes a reasonable planning method for water meter replacement which can minimize the metering under-registration for an increasement of revenue water. The increment analysis of real water usage was used to establish a replacement plan. The meter replacement database collected from K City was used as the basis of this analysis. The database included 964 connections of domestic and non-domestic consumers that had their meter replaced by aging at 2011. The result showed that the corelation between unregistered water volume and water meter age was lower than commonly expected where the current criteria of replacement is only water meter age(8 years) excluding the meters older than 13 years. And in the analysis result of water usage for 8 years, the total amount and increment of water usage had a significant effect on unregistered water volume. However the relation was different tendency as a total volume and slope of increment. In case of total water volume was larger than 10,000, larger than 7,000 and increment of 0.0 ~ -0.3, larger than 6,000 and increment more than -0.3 were analysed to need a replacement because of metering under-registration.