• Journal of the Korean GEO-environmental Society
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• v.13 no.7
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• pp.13-17
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• 2012

Recently, our ocean development paradigm is changing so that the development focus has been moved from the port facility developments to creating useful marine space. This paradigm accords well with the current green technology and helps the growth of service industries and the development from this paradigm can become a national land mark. Accordingly, the concept of creating marine waste landfill by the development of resource recycling technology has been introduced for eco-friendly space as an artificial island in future. Therefore, this study introduces the reactive vertical drainage method that is to pursue the purification of pollutants as well as stabilization of newly deposited soils in marine environments. To install the reactive vertical drainage piles for more effective feasibility and constructability, placements of drainage mid-layer are considered in the geotechnical viewpoint. Consolidation characteristics were evaluated by standard consolidation tests after several types of model test. As s result, the application of mid-layer drainage is strongly recommended in the reactive vertical drainage to quickly stabilize newly deposited soils. And vacuum consolidation method has better consolidation characteristic than vertical loading method in terms of the settlements predicted by additional stress for further use as an artificial island.

• Geotechnical Engineering
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• v.9 no.2
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• pp.27-40
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• 1993

This paper proposes a new procedure carrying out a series of consolidated-undrained triaxial tests with a specimen. In this procedure high confining pressure applied to the specimen keeps constant during the test and each stage of consolidation can be controlled by partial drainage. With this procedure the test time is remarkably reduced by performing a series of triaxial tests with a single specimen. In order to verify the appliesbility of the procedure, standard triaxial compression tests and conventional multi -stage triaxial testy are performed for both undisturbed and disturbed samples and the results are compared with those of the proposed procedure. The comparison shows that strength parameters determined by the proposed procedure are well agreed with those of the other tests and thus it can be said that the procedure is very effective and practical in determining strength parameters.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.407-410
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• 2003

The actual quality of the concrete in the structure for Irrigation may differ from that represented by the cylinders because the age, consolidation, or curing of the in-place material may not be well represented by the standard test specimens. The objective of this paper is to offer a base data of specification is the best fit the ready-mixed concrete strength to the specified, and to address this deficiency, so that the strength information of the concrete in the structure for Irrigation can be rationally accounted for in the assessment of the quality condition of this. The strength of concrete in the hydraulic structures is checked using strength of core obtained from that, and 28-day-old cylinder strength is analyzed using cylinder data of the ready-mixed concrete.

• Journal of the Korean Society for Heat Treatment
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• v.25 no.3
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• pp.138-145
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• 2012

An ${\alpha}$-Ferrite (Fe) powder dispersed with 4 vol.% of $Al_2O_3$ was successfully produced by a simple miling at 210 K with a mixture of $Fe_2O_3$, Fe and Al ingredient powders, followed by 2 step high temperature consolidation: Hot Pressing (HP) at 1323 K and then Hot Isostatic Pressing at 1423 K. The microstructure of the consolidated material was characterized by standard metallographic techniques such as XRD (X-ray Diffraction), TEM and STEM-EDS. The results of STEM-EDS analysis showed that the HIPed materials comprised a mixture of pure Fe matrix with a grain size of ~20 nm and $Al_2O_3$ with a bimodal size distribution of extremely fine (~5 nm) and medium size dispersoids (~20 nm). The mechanical properties of the consolidated materials were characterized by compressive test and micro Vickers hardness test at room temperature. The results showed that the yield strength of the ODS (Oxide Dispersion Strengthened) Fe alloy are as much as $674{\pm}39$ MPa and the improvement of the yield strength is attributed to the presence of the fine $Al_2O_3$ dispersoid.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.2
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• pp.515-527
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• 2014

This study conducted experiment for understanding engineering characteristics of domestic sands by examining standard sand and sand from Yokji Island and Nakdong River in terms of confining pressure, $K_0$, over consolidation and relative density factors through triaxial compression test. The test showed that deviator stress by strain positively changed as confining pressure and relative density grow while $K_0$ and over consolidation factors do not directly correlated with it. Angle of internal friction decreases as confining pressure increases which strengthens contact force between particles, and declines as relative density drops, whereas $K_0$ and over consolidation factors hardly affect the results. When it comes to volumetric strain, volume expansion decreases as confining pressure increase due to crushability and rearrangement of particles while $K_0$ and over consolidation shows same movement unconditionally, and relative density appears compressed as it grows at the beginning however it expands as axial strain increases. Modulus of elasticity ($E_{sec}$) by strain has tendency into convergence resulting in initial secant modulus of elasticity ($E_{ini}$) > secant modulus of elasticity($E_{sec}$) > tangent modulus of elasticity ($E_{tan}$). On the other hand, it grows as confining pressure and relative density increase while indicating similar modulus of elasticity ($E_{sec}$) regarding on $K_0$ and over consolidation. Slope of critical line (M) tended to decrease as confining pressure increases, follow same line according to $K_0$, confining pressure and relative density, and increase as relative density grows.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.1
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• pp.183-194
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• 2004

It's essential process to study non-linear material function related to characteristics of compressibility and permeability when we predict the consolidation behavior of soft clay ground. In this study, laboratory tests were conducted to find out the material function using marine clay. Standard oedometer test and Rowe cell test were performed with conditions, which were classified into vertical drainage only, radial drainage only and vertical-radial drainage case. Modified oedometer test equipment was developed to find out the material function and special extrusion device was originated to minimize the sample disturbance effect. Reliability of the results in modified oedometer test could be confirmed by comparing with the Rowe cell's one. Effective stress - void ratio - permeability relations were analyzed using all testing results. As a result, void ratio with effective stress level could be expressed by the power function and permeability with void ratio could be expressed by exponential function. In soft clay with high initial water content and low shear strength, non-linear characteristics related to compressibility and permeability varied with wide range by the effective stress levels. It's important to note that non-linearity of the material function should be considered at prediction of the consolidation behavior.

• Journal of the Korean GEO-environmental Society
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• v.23 no.5
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• pp.15-24
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• 2022

In order to improve dredged area, long time and high cost is needed because of bad engineering and physical conditions. And there is no suitable example of pipe mixing method at domestic site. Moreover, applicability and effectiveness of this method is uncertain and shows different results between site and laboratory test. In order to solve these problems, we determined proper grain size distribution and water content range using dredged soil and reformed material (standard sand & material controlling grain size distribution) in the laboratory test. As a result, we confirmed that coefficient of sediment consolidation is increased and there is an improvement about separation sedimentation. Undrained shear strength was derived by water content of reformed dredging soil through regression analysis of test results. We suggest the correlation equation for determining mixing ratio.

• International Journal of Computer Science & Network Security
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• v.22 no.12
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• pp.217-228
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• 2022

The study aimed to build an electronic strategy in innovative learning situations for the role of education in combating intellectual currents. A total of 525 Saudi university faculty members and general education teachers were surveyed using two electronic questionnaires. Arithmetic averages and standard deviations, One-way ANOVA, Scheffé's test, Pearson's correlation coefficient, and Cronbach's alpha stability coefficient were used as statistical methods. The study statistically identifies the differences between the study sample at the level of significance (0.05). and the design of a digital application for individual learning to combat deviant intellectual currents to activate them in light of Saudi Vision 2030 by combining the theoretical academic material and turning it into a learning e-game called (crosswords). The game is equipped with hyper media that supports education with entertainment to direct ideas towards the promotion of identity, the development of values towards moderation and the consolidation of intellectual security. Additionally, the learning e-game represents awareness messages in three short films to activate the role of curricula and intellectual awareness centers to apply realistically, innovatively, and effectively.

• Journal of the Korea Convergence Society
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• v.8 no.2
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• pp.157-162
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• 2017

Inorganic stiffening agents were prepared by mixing paper sludge incineration ash, blast furnace slag fine powder quicklime, anhydrous gypsum and fly ash. The main components of the solidifying agent developed for sludge treatment were SiO, $Al_2O_3$, $TiO_2$, $Fe_2O_3$, $Mn_2O_3$, CaO, MgO, $Na_2O$, $K_2O$, $P_2O$, and $SO_3$. Unlike cement, the developed solidifying agent did not contain $Cr^{6+}$, which is known as a carcinogen. Heavy metals and oil contaminated soil were mixed with solidifying agent and cured for 7 days and the heavy metal content was below the environmental standard. Sewage sludge cake, food waste and solidifying agent were mixed with each other, and after 7 days curing, soil component test showed that the heavy metal content was below the environmental standard. After mixing the sludge, solidifying agent and additive mixture into the beaker, the ammonia concentration was measured to be 0 after 3 days.

• Journal of Platform Technology
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• v.8 no.2
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• pp.32-43
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• 2020

The Unmanned Aerial Vehicle(UAV) system has been mainly used for military domains, but it also widely applied to used in the civilian domains. In civilian domains, low-cost and small-sized UAV systems are mainly applied in various industries. The software that operates UAV systems has a lot of common functions. However, even though there are many common functionalities of the software, changing the devices may cause a problem requiring software modification. These problems degrade interoperability, modularity and portability in UAV systems. In order to solve the problems, an Open System Architecture(OSA) has been proposed. In this paper, we propose a UAV system software architecture based on Future Airborne Capability Environment(FACE) standard. Our system can support UAV systems of various platforms in the civilian domains, which is supplied in small quantity batch production. And it has the advantages of software consolidation and portability. Finally, We describe the development and conformant methodology of the software based on the FACE standard using open development tools.