• Food Science of Animal Resources
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• v.41 no.2
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• pp.288-299
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• 2021

Biofilm formation of Geobacillus thermodenitrificans, Geobacillus thermoglucosidans and Anoxybacillus flavithermus in milk on stainless steel were monitored at 55℃, 60℃, and 65℃ for various incubation times. Although species of Geobacillus showed a rapid response and produced biofilm within 4 h on stainless steel, a delay (lag time) was observed for Anoxybacillus. A hyperbolic equation and a hyperbolic equation with lag could be used to describe the biofilm formation of Geobacillus and Anoxybacillus, respectively. The highest biofilm formation amount was obtained at 60℃ for both Geobacillus and Anoxybacillus. However, the biofilm formation rates indicated that the lowest rates of formation were obtained at 60℃ for Geobacillus. Moreover, biofilm formation rates of G. thermodenitrificans (1.2-1.6 Log10CFU/mL∙h) were higher than G. thermoglucosidans (0.4-0.7 Log10CFU/mL∙h). Although A. flavithermus had the highest formation rate values (2.7-3.6 Log10CFU/mL∙h), this was attained after the lag period (4 or 5 h). This study revealed that modeling could be used to describe the biofilm formation of thermophilic bacilli in milk.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.241-248
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• 2011

Past theories on construction price formation have been shown to be inadequate in terms of their ability to represent real-life industry practice and price formation predictability. In this paper, we develop a theoretical framework on construction price formation that integrates four theories within the domains of marketing, learning, resource management and economics. These are: (i) marketing pricing theory; (ii) experiential and organisational learning theory; (iii) resourced based theory and (iv) microeconomic theory. Utilising pricing theory from marketing, a foundation is able to be created for the procedure of construction price formation, namely: (i) identifying the objectives; (ii) assessing the tendering environment; and (iii) formation of the price. However, understanding contractors' decision making process in tender pricing as such can be attributed to theories of experiential learning and consequently organisational learning. It is argued that contractors do learn from past experience and history and are able to adapt to different market conditions. In formation of the price, neoclassical microeconomics is able to provide additional insight in terms of the supply and demand model and consideration of the market conditions. Interrelated with the microeconomic concept of scarcity, we appreciate that contractors do have limited resources that affect their tender pricing decisions and resource based theory is used to substantiate this. Integrating the various theories as a unity allows the broader reality to be visualised and add to our theoretical understanding of construction price formation.

• Economic and Environmental Geology
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• v.29 no.5
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• pp.639-660
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• 1996

The lowest formation of the Cretaceous Gyeongsang Supergroup, the Nakdong Formation, unconformably overlies the gneiss complex basement in Hadong, Gyeongsangnam-do and Gwangyang, Chullanam-do. The Nakdong Formation of the study area is 500-600 m thick and occurs as a belt shape. Based upon lithology, sedimentary structure, and bedding geometry the formation consists of three conglomerate facies (Gd, Gn, Gic), five sandstone facies (Sh-n, Sh-i, Sp, Sr, Sm), and four mudstone facies (Mf, Mfn, Mc, Mv). Sandstone facies are the most prominent in the study area. The twelve facies can be grouped into five facies associations. The depositional settings are elucidated from analyses of 12 facies and five facies associations of the formation. The lower part of the Nakdong Formation was deposited in alluvial plain, and the middle and upper parts were in a riverine system. The lithologies of the Nakdong Formation of the Gyeongsang Basin have been considered to consist of generally conglomerates and pebbly sandstones that were accumulated in alluvial fans. But the common lithology of the study area is sandstone which was formed in lower part of alluvial fan or fluvial setting. It is supposed that the coarser sedimentary sequence distributed west to the study area should be eroded out after deposition and early uplift, and the finer sandstone sequence in the east remains behind. The mineral composition of sandstones and the clast composition of conglomerates indicate that the Nakdong Formation was derived mainly from the metamorphic source rocks. Some reworked intraclasts were also supplied from the intrabasinal sedimentary layers. Paleocurrent data collected from cross-beddings, ripple marks, asymmetric sand dune suggest that most sediments were transported from north to south during the Nakdong Formation time.

• Journal of Veterinary Clinics
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• v.40 no.3
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• pp.175-181
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• 2023

Fucoidan extracted from brown seaweed has a variety of biological activities. Neutrophil extracellular traps (NETs) formation is an immune response for the invasion of pathogens. Neutrophils release granule protein and chromatin that form extracellular fibers that bind microbes. These NETs degrade virulence factors and kill bacteria. The aim of this study was to investigate the effect of fucoidan on NET formation of porcine peripheral blood polymorphonuclear cells (PMNs). The NET formation was determined by fluorescence emission of propidium iodide (PI) in PMNs by a fluorescence microplate reader. The production of tumor necrosis factor (TNF)-α from peripheral blood mononuclear cells (PBMCs) was measured by ELISA method. Fucoidan itself did not show any direct effect on NET formation. However, NET formation of PMNs was increased by the culture supernatant from PBMCs treated with fucoidan. The NET formation of PMNs were also enhanced by treatment with recombinant porcine (rp) TNF-α. The ability of culture supernatant from PBMCs treated with fucoidan to increase the NET formation of PMNs was inhibited by addition of goat anti-rp TNF-α polyclonal antibody (pAb) (IgG) prior to the culture. The increase of NET formation by rp TNF-α was also inhibited by goat anti-rp TNF-α pAb (IgG). The level of TNF-α in culture supernatant from PBMCs was increased by treatment with fucoidan. These results suggest that fucoidan increases porcine NET formation, which is mediated by TNF-α produced from PBMCs.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.41.1-41.1
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• 2015

Hierarchical galaxy formation models under LCDM cosmology predict that the most massive structures such as galaxy clusters (M > $10^{14}M_{\odot}$) appear late (z < 1) in the history of the universe through hierarchical clustering of small objects. Galaxy formation is also expected to be accelerated in overdense environments, with the star formation rate-density relation to be established at z ~ 2. In this talk, we present our search of massive structures of galaxies at 0.7 < z < 4, using the data from GOODS survey and our own imaging survey, Infrared Medium-deep Survey (IMS). From these studies, we find that there are excess of massive structures of galaxies at z > 2 in comparison to the Millennium simulation data. At 1 < z < 2, the number density of massive structures is consistent with the simulation data, but the star formation history is more or less identical between field and cluster. The star formation quenching process is dominated by internal process (stellar mass). The environmental effect becomes important only at z < 1, which contributes to create the well known star formation-density relation in the local universe. Our results suggest that galaxy formation models under LCDM cosmology may require further refinements to match the observation.

• Journal of Ocean Engineering and Technology
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• v.28 no.4
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• pp.363-369
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• 2014

In this paper, a practical controller for a group of USVs is proposed in order to avoid matrix inversion problems in computation. Using nonlinear mapping, a formation composed of nonholonomic agents can be stabilized even when the formation is stationary. Since there is no matrix inversion in computing the control law, the computation complexity can be resolved. A controller for stabilizing the formation errors in the presence of model uncertainty is considered using the Lyapunov redesign method. The asymptotic stability of the formation errors is shown. It is also shown that the proposed controller can be applied to guide a formation to a different shape without modification.

• Journal of Environmental Science International
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• v.6 no.2
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• pp.113-124
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• 1997

The basic mechanism of the granular sludge formation which is the most important factor in the start-up and stable operators is not confirmed yet. In this study, the effect of granular sludge formation was investigated with the different substrate concentrations and the various ratios of substrate supply/deficiency. The granular sludge formation in the UASB reactor was closely related to the substrate concentrations and the ratio of substrate supply/deficlency The granular sludge formation was not accelerated at low substrate concentration. It was convinced that granular sludge formation was accelerated when the substrate supply with high concentration was stopped at UASB reactor. From this experiment, it was estimated that granular sludge was formed by the combination of hydrogen utilizing bacteria that form hydrogen condition and acid forming bacteria at substrate deficit condition by mutual symbiosis. Though the removal efficiency of organic matter was decreased as the influent substrate concentration was Increased, the higher the influent substrate the better the granular sludge formation.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2005.11a
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• pp.519-522
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• 2005

This paper presents a self-organizing scheme for multi-agent swarm systems based on coupled nonlinear oscillators (CNOs). In this scheme, unicycle robots self-organize to flock and arrange group formation through attractive and repulsive forces among themselves. It is also shown how localized distributed controls are utilized throughout group behaviors such as formation and migration. In the paper, the proposed formation ensures safe separation and good cohesion performance among the robots. Several examples show that the proposed method for group formation performs the group behaviors such as reference path following, obstacle avoidance and flocking, and the formation characteristics such as flexibility and scalability, effectively.

• International Journal of Aeronautical and Space Sciences
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• v.10 no.1
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• pp.58-66
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• 2009

Formation controller for multiple spacecrafts is designed based on a decentralized approach. The objective of the proposed controller is to make each spacecraft fly to the desired waypoints, while keeping the formation shape of multiple spacecrafts. To design the decentralized formation controller, the output feedback linearization technique using error functions for goal convergence and formation keeping is utilized for spacecraft dynamics. The primary contribution of this paper is to proposed optimal controller for formation flying based on the decentralized approach. To design the optimal controller, eigenvalue assignment technique is used. To verify the effectiveness of the proposed controller, numerical simulations are performed for three-dimensional waypoint-passing missions of multiple spacecrafts.

• Journal of the Korean Wood Science and Technology
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• v.46 no.6
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• pp.692-702
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• 2018

Streptococcus mutans causes oral diseases, including tooth decay, by producing a biofilm called plaque. Therefore, inhibition of biofilm formation is essential for maintaining oral health. Plants produce a variety of secondary metabolites, which act as starting sources for the discovery of new bioactive chemicals that inhibit biofilm formation of S. mutans. Previous studies have reported on chemicals with antibiotic activity for the inhibition of biofilm formation by S. mutans. In this study, nine plant extracts from Melonis Pedicellus, Agastachis Herba, Mori Cortex Radicis, Diospyros kaki leaves, Agrimoniae Herba, Polygoni Multiflori Radix, Lycopi Herba, Elsholtziae Herba, and Schizonepetae Spica were screened for the inhibition of biofilm formation from a plant extract library. The water-soluble compounds of the extracts did not affect cell growth but selectively inhibited biofilm formation. These results suggest that the selected plant extracts constitute novel biofilm formation inhibitors, with a novel biological mechanism, for improving oral hygiene.