• Journal of Mechanical Science and Technology
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• v.16 no.2
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• pp.192-202
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• 2002

In particle or short-fiber reinforced composites, cracking of the reinforcements is a significant damage mode because the cracked reinforcements lose load carrying capacity. This paper deals with an incremental damage theory of particle or short-fiber reinforced composites. The composite undergoing damage process contains intact and broken reinforcements in a matrix. To describe the load carrying capacity of cracked reinforcement, the average stress of cracked ellipsoidal inhomogeneity in an infinite body as proposed in the previous paper is introduced. An incremental constitutive relation on particle or short-fiber reinforced composites including progressive cracking of the reinforcements is developed based on Eshelby's (1957) equivalent inclusion method and Mori and Tanaka\`s (1973) mean field concept. Influence of the cracking damage on the stress-strain response of composites is demonstrated.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.611-618
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• 2002

In this study the CGS as an injection method by low slump mortar was performed the pilot test to confirm the applicability of this method and the effectiveness of settlement restraint. From the results, there has been concluded the construction control standard such as an institutional diameter, space, depth, injection materials, Infection pressure etc. Also, there has been estimated the ground improvement effectiveness which has resulted from the field investigation and consolidation test etc. From the results, in the adjacent ground the CGS, generally, has been confirmed to in-crease ground strength to improve the consolidation characteristic obtained from the field investigation and consolidation test. Especially, the CGS which performed the larger stiffness to the ground has been concluded that the settlement restraint to the ground complicates the ground effect which Increases the bearing capacity and stress assignment. So, the CGS can be considered as an effective method to increase the bearing capacity as well as the settlement restraint of soft ground.

• Smart Structures and Systems
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• v.30 no.2
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• pp.209-219
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• 2022

The determination for bearing capacity of precast nodular piles is conventionally time-consuming and high-cost by using numerous experiments and empirical methods. This study proposes an intelligent method to evaluate the bearing capacity and shaft resistance of the nodular piles with high efficiency based on long short-term memory (LSTM) approach. A series of field tests are first designed to measure the axial force, shaft resistance and displacement of the combined nodular piles under different loadings, in comparison with the single pre-stressed high-strength concrete piles. The test results confirm that the combined nodular piles could provide larger ultimate bearing capacity (more than 100%) than the single pre-stressed high-strength concrete piles. Both the LSTM-based method and empirical methods are used to calculate the shift resistance of the combined nodular piles. The results show that the LSTM-based method has a high-precision estimation on shaft resistance, not only for the ultimate load but also for the working load.

• Korean Journal of Organic Agriculture
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• v.20 no.1
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• pp.71-80
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• 2012

This experiments was conducted to investigate the influence on growth of rye, triticale with legume and investigated their productivity, feed value and stock carrying capacity in order to select the appropriate forage species in the central region of Korea. In the results, Rye+Red clover showed 5.2ton/ha of dry matter yield. But there was no significant difference with Triticale+Red clover and Rye in upland field. In paddy field, Rye+Hairy vetch showed 5.2ton/ha, but there was no significant difference with Triticale+Hairy vetch and Rye. Mixture effects with Rye, Triticale and Red clover, Hairy vetch by relative yield were more than 1.00 compared to monoculture, and their mixture effect was recognized in upland and paddy field. Relative feed value was highest in the applications of Triticale mixture in upland and paddy field. The average value of $K_{CP}$ and $K_{TDN}$ showed the highest one as 2.75head/ha/yr in Rye+Red clover in upland field and 2.84head/ ha/yr in Triticale+Hairy vetch in paddy field. According to the results, Rye+Red clover in upland field and Triticale+Hairy vetch in paddy field were considered to be the most appropriate winter forage crops for the central region of Korea in terms of productivity, feed value and stock carrying capacity.

• Journal of the Korean GEO-environmental Society
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• v.6 no.3
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• pp.47-54
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• 2005

In many practical cases, design methods of pile have been used mainly semi empirical bearing capacity equations. It can be done that confirmation of pile bearing capacities through using of dynamic and static tests during constructing or after constructions. If a prediction of layered point pile bearing capacity could be done through simple tests during field investigation, it could be done that more reliable design of pile than a prediction of using semi empirical equations or static formulations. This paper suggests a method to estimated point bearing capacity during in-situ investigation by using the dynamic rod model pile and verifies the point bearing capacity compare with results of static pile load tests. From test results, the unit ultimate point bearing capacities are relatively similar through a dynamic rod model pile tests and static pile load tests. The unit ultimate point bearing capacity by using N value is shown about 50 % value of measured unit ultimate point bearing capacity from field test result and the prediction of the unit ultimate point bearing capacity by using N value is shown very conservative, illogical and uneconomical pile designs.

• The Korean Journal of Ecology
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• v.19 no.5
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• pp.453-463
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• 1996

Diurnal changes of microclimatic conditions and tissue water relations were measured at two sites where Carpinus laxiflora and C. cordata were allopatrically distributed. The microclimatic conditions at a site where C. laxiflora was distributed produced severe water stress condition during summer months. Daily maximum temperature reached $30.4^\circC$ and the highest vapor pressure deficit was 1.31 KPa when 13 rainless days were continued. During this period soil water content decreased to below the field capacity even at a depth of 20 cm and xylem pressure potential also decreased to ­2.04 MPa. However, turgor potential was maintained more than 0.4 MPa. Patterns of stomatal conductance were changed with evaporative demand and soil water availability. On the other hand, microclimatic conditions at a site where C. cordata was distributed were moderate water strees condition compared with those at a site C. laxiflora was distributed. Though soil water content was maintained above field capacity C. cordata showed a remarkable decrease in turgor potential and stomatal conductance throughout the experiment. These results indicate that there is a difference in habitat characteristics between the two species and C. laxiflora is more resistant than C. cordata to water stress.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.1
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• pp.9-16
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• 2016

This study was conducted to analyze fishing capacity and bycatch by mesh size and entrance size of spring net pot conducted by water tank and field experiment. The water tank experiments were conducted by using traps with mesh size of 22 mm and entrance size of 120 mm and 140 mm, respectively in the water tank of NIFS. The field experiment was conducted using 5 kinds of spring net pot with mesh sizes of 20 mm, 22 mm, 35 mm and entrance size of 120 mm, 130 mm, 140 mm, 360 mm by coastal trap fishery vessel operating around the area of Geoje island. In the result of water tank experiments, the catch of conger eel was 1.5 times higher when using trap with entrance size of 140 mm than that of 120 mm. In the field experiment, when using same mesh size, the larger the entrance size, the higher amount of conger eel catch, bycatch and number of bycatch species. When using the same entrance size, the larger the mesh size, the lower amount of conger eel catch and number of bycatch species, whereas the amount of bycatch showed increasing trend.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.2
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• pp.175-181
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• 1982

This experiment was carried out to study the influence of the various soil water regimes on photosynthesis and growth and development of ginseng plant (3 years). The results were as follows: optimum soil water content for root dry weight and diameter appeared to be 62% of field capacity (13.9% fresh weight basis). The 62% field capacity showed superiority in leaf area, leaf dry weight and also in number of flower, fruit, seed per plant. Net photosynthesis rates per unit area increased with increasing soil water content but net photosynthesis rates per plant were superior in 62% field capacity. Rates of transpiration increased linearly with increasing soil water content but density of stomata decreased with increasing soil water content.

• Journal of Biosystems Engineering
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• v.30 no.3 s.110
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• pp.141-146
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• 2005

Worldwide consumption of vegetable soybean has been increasing recently, but, in the process of vegetable soybean production threshing and seperation work accounts for about $80\%$ of overall labor. Therefore, developing of the vegetable soybean thresher is necessary to reduce the cost of labor. The main objective of this study is to develop the vegetable soybean thresher which is suitable for domestic circumstances. The threshing and separating performance, operating cost, and field capacity of developed vegetable soybean thresher are investigated and analysed. The results are as follows. The effective field capacity of the developed vegetable soybean thresher was shown as 4.8hr/10a, and reduced as much as 11.7 times compared with human labor. The ratio of unthreshed soybean-pod to stem after threshing work was shown as $1.5\%$ and the damaged pod ratio of detached soybean was shown as $1.8\%$. The cost of human labor was shown as 2,560,000 won/ha, but the operating of the developed vegetable soybean thresher was shown as 503,000won/ha. If the vegetable soybean thresher would be used in our farm, the minimum cultivation area appeard to be 22.7a for the cost effective management.

• Structural Engineering and Mechanics
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• v.73 no.5
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• pp.515-527
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• 2020

This paper presents a stress field approach for the shear capacity of stirrup-reinforced concrete beams that explicitly incorporates the contribution of principal tensile stresses in concrete. This formulation represents an extension of the variable strut inclination method adopted in the Eurocode 2. In this model, the stress fields in web concrete consist of principal compressive stresses inclined at an angle θ combined with principal tensile stresses oriented along a direction orthogonal to the former (the latter being typically neglected in other formulations). Three different failure mechanisms are identified, from which the strut inclination angle and the corresponding shear strength are determined through equilibrium principles and the static theorem of limit analysis, similar to the EC-2 approach. It is demonstrated that incorporating the contribution of principal tensile stresses of concrete slightly increases the ultimate inclination angle of the compression struts as well as the shear capacity of reinforced concrete beams. The proposed stress field approach improves the prediction of the shear strength in comparison with the Eurocode 2 model, in terms of both accuracy (mean) and precision (CoV), as demonstrated by a broad comparison with more than 200 published experimental results from the literature.