• 전자공학회논문지S
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• 제35S권3호
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• pp.9-18
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• 1998

For constructionof the next generation satellite B-ISDN/ATM networks considering integration with terrestrial information infrastructure networks, various high speed and wideband satellites with be launched and they will make used of frequency reue techniques for efficient management of limited frequency resource. Therefore, CCI(Co-Channel Interference) inherent in frequency reuse will be a dominant factor in performance degradation of satellite networks. This paper alanyzes the ATM cell transmission performance degradation caused by CCI. The satellite link, including up-link and down-link thermal noise, CCI, and nonlinear satellite transponder, is modeled and interleaving technique is used for compensating the ATM cell transmission performance degradation caused by burst error of satellite link. First, each satellite link subsystem is analyzed in detail and then end-to-end ATM cell transmission performance is evaluated with BER and CLR. Specifically, ATMcell transmission performance degradation caused by CCI is evaluated in detail.

• ETRI Journal
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• 제22권4호
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• pp.40-50
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• 2000

We apply a "sliding-window" Maximum Likelihood(ML) estimator to estimate traffic parameters On-Off source and develop a method for estimating stochastic predicted individual cell arrival rates. Based on these results, we propose a simple Connection Admission Control(CAC)scheme for delay sensitive services in broadband onboard packet switching satellite systems. The algorithms are motivated by the limited onboard satellite buffer, the large propagation delay, and low computational capabilities inherent in satellite communication systems. We develop an algorithm using the predicted individual cell loss ratio instead of using steady state cell loss ratios. We demonstrate the CAC benefits of this approach over using steady state cell loss ratios as well as predicted total cell loss ratios. We also derive the predictive saturation probability and the predictive cell loss ratio and use them to control the total number of connections. Predictive congestion control mechanisms allow a satellite network to operate in the optimum region of low delay and high throughput. This is different from the traditional reactive congestion control mechanism that allows the network to recover from the congested state. Numerical and simulation results obtained suggest that the proposed predictive scheme is a promising approach for real time CAC.

• 한국통신학회논문지
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• 제21권10호
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• pp.2687-2702
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• 1996

It is desirable that the implementation of next generation information infrastructure is the Integrated Network combining the satellite and the terrestrial network. The application of the ATM network being the dominant infrastrure of terrestrial network to the satellite network is being studied variously. Considering these concepts, this paper analyzes due to ATM transport via satellite, evaluates the degradation of QoS and proposes reliable method of ATM cell transport via satellite. Because ATM is investigated with the optical fiber which is almost error free characteristics, the practical application of ATM transport via satellite essentially need the channel coding(FEC:Forward Error Correction) to enhance BER performance. But using the FEC coding, satellite link has burst error characteristics which evoke severe performance degradation fo ATM QoS. Therefore in satellite link, we analyze burst error characteristics using experimental results of computer simulation. Then to compensate these characteristics, based on this analysis and HEC dual mode algorithm we propose various interleaver structures(Block interleaver, Intra interlever, and Inter-Intra interleaver) to improve cell transmission QoS. We execute performance evaluations of iterleaver structures by computer simulation.

• 전자공학회논문지S
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• 제35S권5호
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• pp.1-10
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• 1998

Satellite communication is getting more important in the coming 21st century because of its wide areas sevice capability, ease of access, and fast channel establishment. As such, satellite communication networks will be the basis of the global communication system in cooperation with the ground ATM networks. In this paper, we consider an efficient transmission methodology of ATM cells over the satellite communication channel. We first analyze possible bottlenecks and performance deterioration factors in the case, and then propose an enhanced cell trasmission mechanism. In order to use satellite channel for ATM cell transmission, the application of complicated channel coding is inevitable. However, the forwared error control such as convolutional encoding brings forth burst errors, which calls for the application of some kind of interleaving mechanism to randomize the burst errors at the receiver. Another aspect which should b econsidered in satellite communication system is the inherent transmission delay, which can be very considered in satellite communication system is te inherent transmission delay, which can be very critical to the delay-sensitive ATM traffic. Therefore, we propose that the processing delay at the block interleaving stage should be controlled propose a variable-size block interleaving mechanism which utilizes the predicted transmission delay for each traffic in the queues of the transmitter. According to the computer simulation, the proposed mechanism could improve the overall performance by drastically reducing the ATM cell drop rate owing to the excessive transmission delay.

• Asian-Australasian Journal of Animal Sciences
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• 제20권4호
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• pp.501-510
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• 2007

The present study was conducted to establish primary bovine muscle satellite cell (MSC) culture conditions and to investigate the effects of various steroid hormones on transcription of the genes involved in muscle cell proliferation and differentiation. Of three different types of proteases (type II collagenase, pronase and trypsin-EDTA) used to hydrolyze the myogenic satellite cells from muscle tissues, trypsin-EDTA treatment yielded the highest number of cells. The cells separated by hydrolysis with type II collagenase and incubated on gelatin-coated plates showed an enhanced cell attachment onto the culture plate and cell proliferation at an initial stage of cell growth. In this study, the bovine MSCs were maintained in vitro up to passage 16 without revealing any significant morphological change, and even to when the cells died at passage 21 with decreased or almost no cell growth or deformities. When the cells were incubated in a steroid-depleted environment (DMEM(-)/10% CDFBS (charcoal-dextran stripped FBS)), they grew slowly initially, and were widened and deformed. In addition, when the cells were transferred to an incubation medium containing steroid (DMEM(+)/10% FBS), the deformed cells resumed their growth and returned to a normal morphology, suggesting that steroid hormones are crucial in maintaining normal MSC morphology and growth. The results demonstrated that treatments with 19-nortestosterone and testosterone significantly increased AR gene expression (p<0.05), implying that both testosterone and 19-nortestosterone bind with AR and that the hormone bound-AR complex up-regulates the genes of its own receptor (AR) plus other genes involved in satellite cell growth and differentiation in bovine muscle.

• 한국축산식품학회지
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• 제43권6호
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• pp.1017-1030
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• 2023

Fetal bovine serum (FBS), which contains various nutrients, comprises 20% of the growth medium for cell-cultivated meat. However, ethical, cost, and scientific issues, necesitates identification of alternatives. In this study, we investigated commercially manufactured serum-free media capable of culturing Hanwoo satellite cells (HWSCs) to identify constituent proliferation enhancing factors. Six different serum-free media were selected, and the HWSC proliferation rates in these serum-free media were compared with that of control medium supplemented with 20% FBS. Among the six media, cell proliferation rates were higher only in StemFlex^TM Medium (SF) and Mesenchymal Stem Cell Growth Medium DXF (MS) than in the control medium. SF and MS contain high fibroblast growth factor 2 (FGF2) concentrations, and we found upregulated FGF2 protein expression in cells cultured in SF or MS. Activation of the fibroblast growth factor receptor 1 (FGFR1)-mediated signaling pathway and stimulation of muscle satellite cell proliferation-related factors were confirmed by the presence of related biomarkers (FGFR1, FRS2, Raf1, ERK, p38, Pax7, and MyoD) as indicated by quantitative polymerase chain reaction, western blotting, and immunocytochemistry. Moreover, PD173074, an FGFR1 inhibitor suppressed cell proliferation in SF and MS and downregulated related biomarkers (FGFR1, FRS2, Raf1, and ERK). The promotion of cell proliferation in SF and MS was therefore attributed to FGF2, which indicates that FGFR1 activation in muscle satellite cells may be a target for improving the efficiency of cell-cultivated meat production.

• Asian-Australasian Journal of Animal Sciences
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• 제22권10호
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• pp.1447-1460
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• 2009

Myogenic satellite cells have been isolated and identified by several recently elucidated molecular markers. Furthermore, knowledge about the precise function of these markers has provided insight into the early and terminal events of satellite cells during proliferation, differentiation, transdifferentiation, specification and activation. Recently, quiescent myogenic satellite cells have been associated with possession of Pax 3 and 7 that represent pluripotent stem cells capable of differentiating into other lineages. However, the mechanism by which myogenic satellite cells attain pluripotent potential remain elusive. Later, transdifferentiating ability of these cells to another lineage in the absence or presence of certain growth factor/ or agents has revolutionized the scope of these pluripotent myogenic satellite cells for manipulation of animal production (in terms of quality and quantity of muscle protein) and health (in terms of repair of skeletal muscle, cartilage or bone).

• Animal Bioscience
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• 제36권12호
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• pp.1889-1897
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• 2023

Objective: 'Cultured meat' has been suggested as means of solving the problems associated with overpopulation and gas emissions. Satellite cells are a major component in the production of cultured meat; however, these cells cannot be maintained in vitro over long periods. Fibronectin is a glycoprotein that affects biological processes such as cell adhesion, differentiation, and migration. Unfortunately, the characteristics of porcine satellite cells grown in a long-term culture when exposed to fibronectin-coated dishes are unknown. The objective of this study was to investigate the appropriate concentration of fibronectin coated dishes for proliferation and maintenance of porcine satellite cells at long-term culture. Methods: In this study, we isolated the satellite cells and fibroblast cells with pre-plating method. We next analyzed the cell doubling time, cell cycle, and rate of expressed paired box 7 (Pax7) and myogenic differentiation 1 (MyoD1) in porcine satellite cells cultured with 20 ㎍/mL of fibronectin-, gelatin-, and non-coated dishes at early and late passage. We then analyzed the proliferation of porcine satellite cells with various concentrations of mixed gelatin/fibronectin. We next determined the optimal concentration of fibronectin that would encourage proliferation and maintenance of porcine satellite cells in a long-term culture. Results: Doubling time was lowest when 20 ㎍/mL of fibronectin was used (as tested during an early and late passage). Levels of expressed Pax7 and MyoD1, assessed using immunocytochemistry, were highest in cells grown using fibronectin-coated dishes. The proliferation of gelatin/fibronectin mixed coatings had no significant effect on porcine satellite cells. The concentration of 5 ㎍/mL fibronectin coated dishes showed the lowest doubling time and maintained expression of Pax7. Conclusion: Fibronectin with 5㎍/mL effectively maintains porcine satellite cells, a discovery that will be of interest to those developing the next generation of artificial meats.

• Journal of Animal Science and Technology
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• 제63권4호
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• pp.673-680
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• 2021

The purpose of this study was to establish a basic principal procedure for the processing of cultured meat. The first stage involved isolating satellite cells from the desired muscle of an animal using enzymatic digestion (i.e., by using proteases, collagenases, and pronases). The second stage involved culturing the isolated muscle satellite cells in a growth medium containing fetal bovine serum and penicillin/streptomycin with growth factors for an optimal period of time. The second stage involved a basic method for the isolated muscle cells to proliferate while sub-culturing to further induce differentiation in gelatin-coated culture dishes with the general culture medium. The third stage involved the induction of differentiation of muscle satellite cells or formation of myotubes using myogenic medium. Lastly, the fourth stage involved the identification of cell differentiation or myotube formation (myogenesis) using fluorescent dyes. Moreover, the principle of these protocols can be applied to perform primary culture of animal cells. This study will assist beginners with the technical aspects of culturing meat (isolation, cultivation, and differentiation of muscle satellite cells as well as identification of myotube formation for myogenesis).

• Asian-Australasian Journal of Animal Sciences
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• 제21권3호
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• pp.456-464
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• 2008

Avian and mammalian skeletal muscles exhibit a remarkable ability to adjust to physiological stressors induced by growth, exercise, injury and disease. The process of muscle recovery following injury and myonuclear accretion during growth is attributed to a small population of satellite cells located beneath the basal lamina of the myofiber. Several metabolic factors contribute to the activation of satellite cells in response to stress mediated by illness, injury or aging. This review will describe the regenerative properties of satellite cells, the processes of satellite cell activation and highlight the potential role of satellite cells in skeletal muscle growth, tissue engineering and meat production.