• Korea Science and Art Forum
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• v.16
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• pp.157-169
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• 2014

Lake Biwa Canal was a dream project that reminds us the passion and innovation of Kyoto Citizens more than water supply. It is a modernization project combining engineering knowledge and scientific technology, which started transportation by ship through big-scale civil construction as well as supplying electricity as the first waterpower plant in Japan, and it overcame the physiographic limit through adopting unique method of waterway transportation. Lake Biwa Canal, which has tangible and intangible culture heritage value as the traditional space of Kyoto, the Old Capital of 1200 years, conceives a cultural meaning that is connected through various mutual relation as well as scientific technologic factor. Lake Biwa Canal is not only the function for supplying water to gardens and temples of Kyoto region, but it is also a cultural fruit that is formed by complex causal relationship of various contents such as geographical and environmental background, the phases of the times, local development policy, political circumstances and religions. This study is aimed at interpreting the value of Lake Biwa Canal multilaterally by the convergence of cultural and technological aspects through the view of the world which the age tried to pursue, focusing on the construction of Lake Biwa Canal which was accomplished in the process of promoting the modernization of Kyoto.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.3
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• pp.226-233
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• 2023

In this study, two phases were conducted to investigate the direct injection of gaseous CO₂ into cement mortar. The aim was to advance carbon capture, utilization, and storage (CCUS) technology by harnessing industrial waste CO₂ from the domestic ready-mixed concrete industry. In the first phase, the factors influencing the physical properties of cement mortar when using gaseous CO₂ were identified. This included a review of materials to achieve physical properties comparable to a reference formulation. As a result of this phase, it was confirmed that traditional approaches, such as adjusting the water-to-cement ratio, had limitations in achieving the desired physical properties. Consequently, the second phase focused on the optimization of CO₂-injected mortar. This involved studying the CO₂ application and mixing method for cement mortar. Changes in properties were observed when gaseous CO₂ was injected into the mortar. The optimal injection quantity and time to enhance the compressive strength of mortar were determinded. As a result, this study indicated that an extra mixing time exceeding 120 seconds was necessary, compared to conventional mortar. The optimal CO₂ injection rate was identified as 0.1 to 0.2 % by weight of cement, taking both flowability and compressive strength performance into account. Increasing the CO₂ injection time did not further enhance strength. For this approach to be employed as a CCUS technology, additional studies are required, including a microstructural analysis evaluating the amount of immobilized CO₂.

• Journal of the Korean Recycled Construction Resources Institute
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• v.12 no.2
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• pp.121-127
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• 2024

In this study, the applicability of replacing DG(Desulfurized Gypsum) from oil refinery with CCCMs(Carbon dioxide Conversion Capture Materials) as an ALC(Auto-claved LIghtweight Concrete) raw material was examined, and basic properties of ALC was measured. The main chemical components of DG and CCCMs were CaO and SO₃, and an increase in LOI(Loss of ignition) due to mineral carbonation reaction was verified. The crystalline phases of CCCMs were CaCO₃, CaSO₄, Ca(OH)₂, and CaSO₄·2H₂O. When DG, a raw material for ALC production, was replaced with CCCMs, foaming height, pore shape, absolute dry gravity, and compressive strength results measured similar for all binders. In addition, the formation of tobermorite which is main crystalline phase of ALC was shown for all specimens in microstructural analysis.

• Journal of the Korea Institute of Building Construction
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• v.24 no.2
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• pp.181-191
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• 2024

In the realm of cement manufacturing, concerted efforts are underway to mitigate the emission of greenhouse gases. A significant portion, approximately 60%, of these emissions during the cement clinker sintering process is attributed to the decarbonation of limestone, which serves as a fundamental ingredient in cement production. Prompted by these environmental concerns, there is an active pursuit of alternative technologies and admixtures for cement that can substitute for limestone. Concurrently, initiatives are being explored to harness technology within the cement industry for the capture of carbon dioxide from industrial emissions, facilitating its conversion into carbonate minerals via chemical processes. Parallel to these technological advances, economic growth has precipitated a surge in construction activities, culminating in a steady escalation of construction waste, notably waste concrete. This study is anchored in the innovative production of calcium silicate cement clinkers, utilizing finely powdered waste concrete, followed by a thorough analysis of their mineral phases. Through X-ray diffraction(XRD) analysis, it was observed that increasing the substitution level of waste concrete powder and the molar ratio of SiO₂ to (CaO+SiO₂) leads to a decrease in Belite and γ-Belite, whereas minerals associated with carbonation, such as wollastonite and rankinite, exhibited an upsurge. Furthermore, the formation of gehlenite in cement clinkers, especially at higher substitution levels of waste concrete powder and the aforementioned molar ratio, is attributed to a synthetic reaction with Al₂O₃ present in the waste concrete powder. Analysis of free-CaO content revealed a decrement with increasing substitution rate of waste concrete powder and the molar ratio of SiO₂/(CaO+SiO₂). The outcomes of this study substantiate the viability of fabricating calcium silicate cement clinkers employing waste concrete powder.

• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.2
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• pp.95-102
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• 2000

Experiments related to the field of sericulture started in the years 1900, in Korea. The sericultural experimental station in Korea was first organized among agricultural fields in Korea, indicating that sericulture in Korea was regarded as an important field of agriculture. Sericulture has been devoted to a great deal for the improvement of Korean economy during the past 100 years even under the coarse social circumstances caused particularly by the Korean War, However, the traditional Korean sericulture, aimed to produce silk yarn, was weakened, because of several reasons such as diminishment in silk consumption, increased labor charge in Korea, and so on. After this difficulty time, the Korean sericulture was revolutionized by shifting into functional sericulture from 1995, and the Korean sericulture now plays an important role for the improvement of human health. Mulberry tree, silkworm, and silk have a boundless potential to be developed as resources. We expect the know-how obtained through silkworm research would expand to the other insect research too. Thus, an area of entomological industry is hoped to prosper owing to insect research as well as sericulture. Mulberry tree is known to possess many bio-active substances, so it can be utilized as a resource for substitute medicine and a raw material for the functional food. In addition, an invention of genetically engineered mulberry variety, which will produce more bioactive substances, is expected. Silkworm is one of the most extensively studied insect organisms on the genome so far, Thus, silkworm is expected to be an "insect bio-factory", enabling mass-production of useful proteins by transformation, in which useful foreign genes are assimilated into silkworm. Silk can be transformed into several phases, because it possesses useful functional groups, which are sensitive to chemical reaction. Also, because silk fibrin itself is protein, it has a superior applicability as tissue membrane. Due to this usefulness, many researchers are now working on the silk as food, cosmetic, medical resource, and bioengineering resource, and even an expanded application is expected using silk in the future. Until now, the researches on insects were largely focused on the prevention of the damage caused by pest, instead of a beneficial aspect. However, insects are thought to be the fourth natural resource in the world, possessing unlimited potential as world resources in the near future. Therefore, our entomological research effort should be focused on the subject with potential for industrialization. Such subject includes selecting the insect species useful for environmental evaluation, construction of environment-friendly agricultural ecosystem, pollen mediation, pet, and advanced bio-resources.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7B
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• pp.1239-1251
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• 1999

In this paper a scalable QoS-based hierarchical inter-domain routing scheme for distributed multimedia applications in a high speed wide area network. The problem of QoS-based routing is formulated as a multicriteria shortest path problem, known as NP-complete[21,30]. Our routing scheme consists of two phases. In Phase 1, two graph construction algorithms are performed to model the network under consideration as a graph. The graph contains a part of the network topology which is completely neglected or partially considered by existing routing schemes, thus maintaining more accurate topology information. In Phase 2, a heuristic call-by-call algorithm is performed for selecting a feasible path efficiently in depth first search-like manner on the graph and tailoring to each application's QoS requirements, beginning at a vertex that represents the source node. In this paper, a simple rule is also produced, by which the visiting order of outgoing edges at each vertex on the graph is determined. The rule is based on each edge's the minimum normalized slackness to the QoS requested. The proposed routing scheme extends the PNNI-type hierarchical routing framework. Note that our routing scheme is one of a few QoS-based hierarchical routing schemes that address explicitly the issue of selecting a path with multiple metrics.

• Journal of Intelligence and Information Systems
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• v.15 no.1
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• pp.123-140
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• 2009

Collaborative filtering recommends products using customers' preferences, so it cannot recommend products to the new customer who has no preference information. This paper proposes a novel approach to new customer recommendations using the social network analysis which is used to search relationships among social entities such as genetics network, traffic network, organization network, etc. The proposed recommendation method identifies customers most likely to be neighbors to the new customer using the centrality theory in social network analysis and recommends products those customers have liked in the past. The procedure of our method is divided into four phases : purchase similarity analysis, social network construction, centrality-based neighborhood formation, and recommendation generation. To evaluate the effectiveness of our approach, we have conducted several experiments using a data set from a department store in Korea. Our method was compared with the best-seller-based method that uses the best-seller list to generate recommendations for the new customer. The experimental results show that our approach significantly outperforms the best-seller-based method as measured by F1-measure.

• Korean Journal of Remote Sensing
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• v.28 no.1
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• pp.121-128
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• 2012

High resolution intertidal DEM is a basic material for science research like sedimentation/erosion by ocean current, and is invaluable in a monitoring of environmental changes and practical management of coastal wetland. Since the intertidal zone changes rapidly by the inflow of fluvial debris and tide condition, remote sensing is an effective tool for observing large areas in short time. Although radar interferometry is one of the well-known techniques for generating high resolution DEM, conventional repeat-pass interferometry has difficulty on acquiring enough coherence over tidal flat due to the limited exposure time and the rapid changes in surface condition. In order to overcome these constraints, we tested the feasibility of radar interferometry using Cosmo-SkyMed tandem-like one-day data and ERS-ENVISAT cross tandem data with very short revisit period compared to the conventional repeat pass data. Small temporal baseline combined with long perpendicular baseline allowed high coherence over most of the exposed tidal flat surface in both observations. However the interferometric phases acquired from Cosmo-SkyMed data suffer from atmospheric delay and changes in soil moisture contents. The ERS-ENVISAT pair, on the other hand, provides nice phase which agree well with the real topography, because the atmospheric effect in 30-minute gap is almost same to both images so that they are cancelled out in the interferometric process. Thus, the cross interferometry with very small temporal baseline and large perpendicular baseline is one of the most reliable solutions for the intertidal DEM construction which requires very accurate mapping of the elevation.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.4
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• pp.276-289
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• 2013

In developing offshore wind farms, many environmental issues arise because of the concentration on supply demand and economic logic. Accordingly, community conflict is induced. Especially, recent studies regarding the capacity and location of offshore wind development have been conducted considering wind states and ocean conditions, etc. of coastal seas in Republic of Korea. Nevertheless, studies on the impact of marine environments and ecosystems are very limited so far. Environmental monitoring that follows development projects has been actively done in the offshore wind farms in many developed European countries. In contrast, there is no domestic monitoring data regarding environmental impacts caused by installing and operating offshore wind power. Therefore, the environmental impacts under construction and operation phases as well as the guidelines in the stage of environmental impact assessment suited for domestic coastal seas are well presented in this study by analyzing monitoring cases and references of overseas offshore wind farm. For this reason, this research is ultimately aimed at minimizing the environmental impact in offshore wind farm development and thus simplify administrative procedures in Korea.

• Journal of Digital Contents Society
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• v.16 no.2
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• pp.307-316
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• 2015

Although the use of CAD and CAM technologies has been broadly adopted by architecture-engineering- construction-facility management (AEC/FM) industry as the means of producing complex forms, there are still remained issues such as reducing cost, and enhancing quality and manufacturability. In this paper, to resolve given issues, we suggest a process of rationalization in digital architecture design and fabrication as an integrated approach. The rationalization, which is usually used as the term related with the skin panel of free-form architecture, is a process of re-designing a digital model to meet the requirements of manufacturing considering the gap with an original designs. Thus we classified this process and conducted a case study of fabricated models as an exploratory study. As the result, we found that each phase is connected with other phases with the circulation of information and rationalization process can be determined as the circulative process which re-designs digital model by minimally deviating from the original design based on the information deducted from analysis of inter-compatability of software and requirement of hardware.