• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.3
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• pp.355-362
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• 2009

In this paper, we present a framework for managing group behaviors in multi-agent swarm systems. The framework explores the benefits by dynamic associations with the proposed artificial potential functions to realize complex swarming behaviors. A key development is the introduction of a set of flocking by dynamic association (DA) algorithms that effectively deal with a host of swarming issues such as cooperation for fast migration to a target, flexible and agile formation, and inter-agent collision avoidance. In particular, the DA algorithms employ a so-called systematic singular association (SSA) rule for fast migration to a target and compact formation through inter-agent interaction. The resulting algorithms enjoy two important interrelated benefits. First, the SSA rule greatly reduces time-consuming for migration and satisfies low possibility that agents may be lost. Secondly, the SSA is advantageous for practical implementations, since it considers for agents even the case that a target is blocked by obstacles. Extensive simulation presents to illustrate the viability and effectiveness of the proposed framework.

• Smart Media Journal
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• v.8 no.3
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• pp.41-46
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• 2019

In a MMORPG, a typical application of virtual environment systems, it is a common desire to play in a more realistic environment. However, it is very difficult to provide a latency-free virtual environment to a large user base, mainly due to the fact that the real environment must be configured on multiple servers rather than on single server and that data must be shared on the real server when users move from one region to another. Experiencing response delays continuously in the process of information synchronization between servers greatly deteriorates the degree of immersion. In order to solve this problem, it is necessary to minimize the response delay occurring in the information synchronization process between the servers. In this paper, we propose Migration Agent for efficient information synchronization between field servers providing information of virtual environment and minimizing response delay between Field Server and PC(Player Character) and implement it in cloud computing network. In the proposed system, CPU utilization of field server increased by 6 ~ 13%, and response time decreased by 5 ~ 10 seconds over the existing system in 70,000 ~ 90,000 PCs

• BMB Reports
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• v.51 no.11
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• pp.596-601
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• 2018

Colon cancer is one of the most lethal and common malignancies worldwide. STK899704, a novel synthetic agent, has been reported to exhibit anticancer effects towards numerous cancer cells. However, the effect of STK899704 on the biological properties of colon cancer, including cancer cell migration and cancer stem cells (CSCs), remains unknown. Here, we examined the inhibitory effect of STK899704 on cell migration and CSC stemness. In the wound healing assay, STK899704 significantly inhibited the motility of colon cancer cells. Furthermore, STK899704 downregulated the mRNA expression levels of the cell migration mediator focal adhesion kinase (FAK). STK899704 also suppressed mitogen-activated protein kinase kinase and extracellular signal-regulated kinase, which are downstream signaling molecules of FAK. Additionally, STK899704 inhibited stemness gene expression and sphere formation in colon cancer stem cells. These results suggest that STK899704 can be used to treat human colon cancer.

• Nutrition Research and Practice
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• v.3 no.4
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• pp.259-264
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• 2009

We examined the inhibitory effects of loquat methanol extract on the adhesion, migration, invasion and matrix metalloproteinase (MMP) activities of MDA-MB-231 human breast cancer cell line. Cells were cultured with DMSO or with 10, 25, or 50 ${\mu}g/ml$ of loquat methanol extract. Both leaf and seed extracts significantly inhibited growth of MDA-MB-231 cells in a dose-dependent manner, although leaf extract was more effective. Adhesion and migration were significantly inhibited by loquat extracts in a dose-dependent manner. Loquat extract also inhibited the invasion of breast cancer cells in a dose-dependent manner and leaf extract was more effective than seed extract. MMP-2 and MMP-9 activities were also inhibited by loquat extract. Our results indicate that methanol extracts of loquat inhibit the adhesion, migration and invasion of human breast cancer cells partially through the inhibition of MMP activity and leaf extract has more anti-metastatic effects in cell based assay than seed extract. Clinical application of loquat extract as a potent chemopreventive agent may be helpful in limiting breast cancer invasion and metastasis.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.5
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• pp.974-979
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• 2009

Proliferation of vascular smooth muscle cell(VSMC) is one of the key features in onset of atherosclerosis and restenosis after vascular surgery such as stent implant. Atherosclerotic plaques are usually composed of collagen, elatsin and smooth muscle cells. Release of matrix metalloproteinases(MMPs) is considered to have correlation with development of atherosclerotic plaques. Based on the hypothesis that MMP inhibition would be helpful in the treatment of atherosclerosis, we investigated inhibition of MMP activity and migration of TNF-$\alpha$-induced human aortic smooth muscle cell(HASMC) by Cinnamomi Ramulus(CC). The result from gelatin zymography showed that CC inhibited MMP-9 activity in a dose-dependent manner. In addition, CC considerably inhibited the migration of HASMC induced by TNF-$\alpha$, while it showed little cytotoxic effect on HASMC. These results suggest that CC can be a potential anti-atherosclerotic agent through inhibition of MMP-9 activity and SMC migration.

• Journal of Radiation Protection and Research
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• v.17 no.2
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• pp.49-59
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• 1992

A new model was developed in order to investigate the effects of chelating agents on the migration of a radionuclide in the form of ion or chelate. The migration behavior of the chelated radionuclide was analyzed by formulating a convective-dispersion transport equation which included a degradation of chelating agent and chelated radionuclide. The mathematical model was analytically solved and checked with the existing retardation factor. The results show that the migration velocity of the chelated radionuclide was much faster than the ionic one due to the decreased retardation. Therefore, it was concluded that a new remedial action should be developed to reduce the generation and release of chelating agents from the nuclear power plant into the environment.

• The Journal of the Korea Contents Association
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• v.7 no.9
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• pp.89-99
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• 2007

With the development of the internet technology, network application services based on a large number of network nodes have been focused. However, such application services require much larger network size and traffic than current network. In order to develop them, efficient solutions as well as a simple improvement of network infra processing time are required. In this paper, to contribute a improvement of network computing technology, we design and implement the agent platform software based on the agent technology that performs works independently and asynchronously on a network and platform. The proposed agent platform software supports the scalability to accommodate the number of network hosts with rapid growth, the adaptability on a variable environments, and the availability for a fault-tolerance.

• Journal of Korea Multimedia Society
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• v.7 no.10
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• pp.1421-1435
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• 2004

When various work was given from user, the existing mobile agent model migrated from node to node and process the work at the point that much traffics according to passive routing schedule are happened, until it makes service the work result, time cost of round work process for the distributed nodes are increased. Therefore, the existing agent systems need migration method to solve the problems of agent size increment or a lack of interoperability among agent systems. To solve these problems in this thesis, we design and implement an CORBA-based Mobile Agent Model(CMAM) for the efficient work process into the distributed nodes, when the mobile agents are migrated among the nodes, using an optimal path search by sensing of network traffic.

• Nutrition Research and Practice
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• v.11 no.4
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• pp.275-280
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• 2017

BACKGROUND/OBJECTIVES: Re-epithelialization has an important role in skin wound healing. Astaxanthin (ASX), a carotenoid found in crustaceans including shrimp, crab, and salmon, has been widely used for skin protection. Therefore, we investigated the effects of ASX on proliferation and migration of human skin keratinocyte cells and explored the mechanism associated with that migration. MATERIAL/METHOD: HaCaT keratinocyte cells were exposed to $0.25-1{\mu}g/mL$ of ASX. Proliferation of keratinocytes was analyzed by using MTT assays and flow cytometry. Keratinocyte migration was determined by using a scratch wound-healing assay. A mechanism for regulation of migration was explored via immunocytochemistry and western blot analysis. RESULTS: Our results suggest that ASX produces no significant toxicity in human keratinocyte cells. Cell-cycle analysis on ASX-treated keratinocytes demonstrated a significant increase in keratinocyte cell proliferation at the S phase. In addition, ASX increased keratinocyte motility across the wound space in a time-dependent manner. The mechanism by which ASX increased keratinocyte migration was associated with induction of filopodia and formation of lamellipodia, as well as with increased Cdc42 and Rac1 activation and decreased RhoA activation. CONCLUSIONS: ASX stimulates the migration of keratinocytes through Cdc42, Rac1 activation and RhoA inhibition. ASX has a positive role in the re-epithelialization of wounds. Our results may encourage further in vivo and clinical study into the development of ASX as a potential agent for wound repair.

• Journal of Communications and Networks
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• v.8 no.1
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• pp.123-131
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• 2006

Several distributed architectures, incorporating mobile agent technology, have been recently proposed to answer the scalability limitations of their centralized counterparts. However, these architectures fail to address scalability problems, when distributed tasks requiring the employment of itinerant agents is considered. This is because they lack mechanisms that guarantee optimization of agents' itineraries so as to minimize the total migration cost in terms of the round-trip latency and the incurred traffic. This is of particular importance when MAs itineraries span multiple subnets. The work presented herein aspires to address these issues. To that end, we have designed and implemented an algorithm that adapts methods usually applied for addressing network design problems in the specific area of mobile agent itinerary planning. The algorithm not only suggests the optimal number of mobile agents that minimize the overall cost but also constructs optimal itineraries for each of them. The algorithm implementation has been integrated into our mobile agent framework research prototype and tested in real network environments, demonstrating significant cost savings.