• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.247-248
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• 2010

This study is of manufacturing artificial lightweight aggregates using industrial wastes. The ingredients for manufacturing lightweight aggregate were stone sludge and bottom ash for main materials, and steel slag(SS), glass abrasive sludge(GS) and blast furnace slag(BS) respectively for accessory material. Their precursors were sintered in the range of $1,050{\sim}1,150^{\circ}C$ for 5 min. The sintered results show that the lightweight aggregate with SS had low water absorption ratio and density at $1,150^{\circ}C$. There's a possibility that if GS is used more than the range of this study, GS can be manufactured lightweight aggregate. But it is judged that BS are incongruent to be used for a raw material of lightweight aggregate.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.686-693
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• 2022

Construction is a collaborative endeavor. The complexity in delivering construction projects successfully is impacted by the effective collaboration needs of a multitude of stakeholders throughout the project life-cycle. Technologies such as Building Information Modelling and relational project delivery approaches such as Alliancing and Integrated Project Delivery have developed to address this conundrum. However, with the onset of the pandemic, the digital economy has surged world-wide and advances in technology such as in the areas of machine learning (ML) and Artificial Intelligence (AI) have grown deep roots across specializations and domains to the point of matching its capabilities to the human mind. Several recent studies have both explored the role of AI in the construction process and highlighted its benefits. In contrast, literature in the organization studies field has highlighted the fear that tasks currently done by humans will be done by AI in future. Motivated by these insights and with the understanding that construction is a labour intensive sector where knowledge is both fragmented and predominantly tacit in nature, this paper explores the integration of AI in construction processes across project phases from planning, scheduling, execution and maintenance operations using literary evidence and experiential insights. The findings show that AI can complement human skills rather than provide a substitute for them. This preliminary study is expected to be a stepping stone for further research and implementation in practice.

• Ocean and Polar Research
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• v.40 no.2
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• pp.69-75
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• 2018

We investigated the effects of environmental variations on the growth and survival rate of Stichopus japonicus to determine the optimum environmental conditions for its growth. Literature studies and a 12 month-long diver survey were carried out to understand the habitat, ecology and size of the surveyed area. Based on the collected data, we suggested optimum habitat conditions for releasing S. japonicus. Experiments on releasing S. japonicus were conducted in the breakwater of the Hwagye fishing cooperative in Hwagey-ri, Namhae-un, Gyeongsangnam-do, Korea. To implement the experiments, we divided the surveyed area into 4 sub-areas with different characteristics: (1) sand and silt zone; (2) artificial sea cucumber bank zone; (3) artificial rock bank zone; and (4) marine algae zone. The experiment lasted for 12 months. We released 32,000 sea cucumbers over $120m^2$ of each of the sand and silt zone, artificial rock bank zone and marine algae zone and released 6,000 sea cucumbers over $120m^2$ of the artificial sea cucumber bank zone. The average density of the released sea cucumbers from day 30 to day 360 after the releasing was conducted was the highest in the artificial sea cucumber bank zone ($23.7animal/m^2$), which was followed by artificial rock bank zone ($2.0animal/m^2$), marine algae zone ($1.9animal/m^2$) and sand and silt zone ($0.8animal/m^2$). The analysis on growth showed that the initial average weight of 2.3 g increased on day 360 after the releasing to 12.5 g in the artificial sea cucumber rank zone, 20.2 g in the sand and silt zone, 23.3 g in the artificial rock bank zone and 22.9 g in the marine algae zone. Results from the experiment along with the literature analysis suggest the following optimum habitat conditions: $10-15^{\circ}C$ water temperature; 28-34 psu salinity; 5-10 m water depth; 0.2-0.5 m/s velocity; rock, stone and muddy sand as substrate; and less than 20% mud in the substrate.

• Journal of architectural history
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• v.17 no.2
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• pp.83-102
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• 2008

In the book of , it is recorded that the names of ingressive stone stairs to the main shrine were Cheongwoongyo(blue cloud bridge) and Baekwoongyo(white cloud bridge) and the names of stairs to the paradise hall were Yeonwhagyo(lotus bridge) and Chilbogyo(seven treasure bridge). But, the ingressive stone stairs to the main shrine and the paradise hall are single consecutive stairs with 2 levels respectively. Because of this, it is rather hard to clearly designate the names to the upper level and the lower level stairs. But, of the stairs to the Paradise hall, the lower stairs have a carving of lotus, and the upper stairs have seven stairs. In this aspect of artifacts, we can safely assume that the upper stairs are Chilbogyo and the lower are Yeonwhagyo. But, for the ingressive stairs to the main shrine, there is no such artificial hint. So, it is difficult to designate the upper and the lower stairs for the two bridges. Especially, it is not clear whether the descriptive order of "lower stairs upper stairs" in the names of Yeonwhagyo and Chilbogyo can be applied to the names of stairs to the main shrine. It is because the general descriptive order is "upper lower" rather than "lower upper." Even though there have been many studies on the Bulguksa temple, the study on the ingressive stone stairs to the main shrine has not made till now. Therefore, the study on the position of Cheongwoongyo and Baekwoongyo stairs can have its validity. In this paper, the positional approach to Cheongwoongyo and Baekwoongyo has been made in following aspects: First, the temple structure of Bulguksa; Second, the five element theory of oriental philosophy and the Book of Changes; Third, the directional consciousness of Buddhism. Through the aspects, the validity of up-down position of Cheongwoongyo and Baekwoongyo has been sought. In this research, it can be concluded that the upper level of ingressive stone stairs to the main shrine of Bulguksa is Cheongwoongyo and the lower level is Baekwoongyo. When considered in the Buddhist directional consciousness, it forms the total structure of "East-Cheongwoongyo South- Baekwoongyo West-Yeonwhagyo North-Chilbogyo."

• Conservation Science in Museum
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• v.22
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• pp.41-52
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• 2019

Inner walls of the stone chamber of West Ancient Tomb No. 1 and 2 in Neungsan-ri, Buyeo-gun have been inspected for possible trace of murals. Tomb No.1 has a rough surface finish of the stone wall and no traces of murals was observed in any part of the stone walls except the ceiling part of the main chamber. On the ceiling surface, there is black colored area, which showed same visual characteristics for both the surface and interior upon slight scratch of the surface, suggesting that it may not be a painted layer. In addition, this black material is not artificial stuff like black ink but is confirmed as biotite from X-ray diffraction analysis that is one of the constituents of the stone wall. In case of tomb No. 2, white material, that is confirmed as lime(calcite, CaCO3) by X-ray diffraction analysis, was observed on the wall surface of the east, west and north, suggesting possible existence of murals. The lime layers, however, are located mostly on the entrance of east wall of main chamber and the place of passage whereas they are observed only in lower parts on the other walls. It may have been formed by the inflow of soil and lime from the outside as the form of the lime layer in the east wall corresponds to the traces of soil and lime deposited from the thief pit. Furthermore, the filling material found in the gap between the stone slabs of the four directions and the ceiling was confirmed as clay soil, which is different material from the lime present on the stone wall surface. If the lime layer had been artificially constructed for the purpose of creating murals, it would have been more reasonable to use lime as well in the gap between the stone slabs of the four directions and ceiling. In this regard, we conclude that there are no murals in the Tomb No. 2 in the Neungsan-ri.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.38 no.4
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• pp.74-85
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• 2020

Darangnon in Gachon Village, Namhae-gun, Gyeongsangnam-do, is the first designated environment among Korea's industrial-based historical and cultural sites and is still the only one that involves agricultural activities. Although the stonework, which is the infrastructure environment here, has limitations that inevitably lead to natural and artificial deformation due to its nature, there has been no research to consider the situation so far. As of the end of May 2020, this study investigated and analyzed the damage in the sub-area of the survey, which is approximately 30% of the scope of the designation of the scenic spot, from a quantitative and qualitative perspective. As a result of the study, the state of loss, which reveals the physical damage of the arctic rice paddy stone retaining wall in the environment under investigation, was particularly serious around the coast, in the northern area with high slopes, and near tourist information centers and parking lots. On the other hand, the qualitative aspect of the damage to the stonework was noticeable in the repair of heterogeneous materials on the stone retaining wall adjacent to the village and parking lot, and the landscape damage caused by the cladding of plants was found in an environment far away from the residence. In addition, natural environmental factors such as slopes, elevations, and soil showed a close relationship with the degree of physical damage of the stone retaining wall, the higher the slope, the higher the elevation, and the better the soil drainage, the greater the impact. These results suggest that humanities environmental factors such as cultivation activities and management entities have important factors in the physical damage and management of stone retaining wall. Therefore, it is deemed essential to find management measures with local residents along with improving the agricultural environment, such as securing agricultural water and soil improvement, for the preservation of tuna paddies and stone retaining wall in the future.

• Journal of Conservation Science
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• v.26 no.3
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• pp.325-334
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• 2010

In order to clarify the effect of consolidant, the artificial porous material with low intensity was manufactured using granite powder and Portland cement. We have prepared four kinds of alkoxysilane system consolidants, a acrylic resin and a epoxy resin and investigated about characteristics before and after consolidation. As a result of the research, Silres BS OH 100 was effective for density and surface hardness. SS-101 with hydrophobicity and Site SX-RO with hydrophilicity had the good durability over salts weathering. On the other hand, Syton HT-50 and Paraloid B72 were easily destructed by salt weathering because they were concentrated on surface area by the low penetration depth. Araldite 2020 was the most effective consolidant for improvement of physical properties.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.108-118
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• 2009

Statement of problem: Volume stability, microstructure reproducibility and fluidity along with compatibility with dental stone must be in consideration in order to use tissue conditioner as a material for functional impression. There are few studies concerning the influence of time factor in oral condition on surface roughness of the stone and optimal retention period in the oral cavity considering such changes in surface roughness. Purpose: The purpose of this study was to find out the influence of various kinds of tissue conditioner, its powder/liquid ratio and immersion time on surface roughness of the stone. Material and methods: Materials used in this study were the three kinds of tissue conditioners(Coe-Comfort, Visco-Gel, Soft-Liner) and were grouped into three: group R-mixed with standard powder/liquid ratio that was recommended by the manufacturers, group M-mixed with 20% more powder, group L-mixed with 20% less powder. Specimens were made with the size of 20 mm diameter and 2 mm width. Each tissue conditioner specimens were subdivided into 5 groups according to the immersion time(0 hour, 1 day, 3 days, 5 days, 7 days), completely immersed into artificial saliva and were stored under $37^{\circ}C$. Specimens of which the given immersion time elapsed were taken out and were poured with improved stone, making the stone specimens. Surface roughness of the stone specimens was measured by a profilometer. Results: Within the limitation of this study, the following results were drawn. 1. Major influencing factor on surface roughness of the stone model made from tissue conditioner was the retention period(contribution ratio($\rho$)=62.86%, P<.05) of the tissue conditioner in oral cavity to make functional impression. 2. In case of Coe-Comfort, higher mean surface roughness value of the stone model with statistical significance was observed compared to that of Soft-Liner and Visco-Gel as immersion time changes(P<.05). 3. In case of group L(less), higher mean surface roughness value of the stone model with statistical significance was observed compared to that of R(recommended) and M(more) group as immersion time changes(P<.05). Conclusion: We may conclude that as the retention period of time in oral cavity influences surface roughness of the stone model the most and as the kind of tissue conditioner and its P/L ratio may influence also, clinician should well understand the optimal retention period in oral cavity and choose the right tissue conditioner for the functional impression, thus making the functional impression with tissue conditioner usefully.

• Journal of Korean Society of Rural Planning
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• v.3 no.2
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• pp.81-89
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• 1997

Still today, many streams are channelized and embanked in Korea. On the other hand, some urban streams are being restored to their natural shapes by landscape planners. It would be better to improve rural streams in a way that would not require restoration in later days. Then, one important question is what kind of embankments the residents prefer for what reasons. Five simulated photos showing from very natural to artificial embankments were used in surveying 90 residents of three villages. Major findings are ; 1. Residents regard safety(from flooding) is the most critical factor to be considered in selection of stream bank materials. 2. They think ideal materials are natural stones or concrete blocks as they look tidy. Concrete retaining walls or vegetated natural slopes are not regarded good. 3. The most preferred material is concrete retaining wall, and the least preferred is vegetated natural slope. They prefer concrete retaining wall which they do not think an ideal material, because it will make a safe bank. 4. Natural stone bank is most preferred for its apperance, and vegetated natural slpoe is most disliked as it may collapse and as it does not look clean.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2009.04a
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• pp.59-63
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• 2009

Structures show the phenomena of deformation and lowering of function with time-lapse by artificial environments and changes of geotechnical conditions or accumulation of initial deformation elements. This study aims the structural assessment of cultural heritage. Non-destructive evaluation techniques were applied to protect it from survey: 3D precise laser scanning surveying system was applied to measure the exact size, displacement and declining angles.