• The Journal of Korean Institute of Communications and Information Sciences
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• 제22권8호
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• pp.1755-1764
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• 1997

In this paper, we proposed the mechanism for the buffer allocation and a cell scheduling method with logical separation a single buffer in the ATm switch, and analyzed the cell loss probability and the delay of each trafic (CBR/VBR/ABR) based on the weighted value and the dynamic cell service scheduling algorithm. The proposed switch buffering system classifies composite trafics incoming to the switch, according to the characteristic of traffic, then stores them in the logically separated buffers, and adopts the round-robin service with weighted value in order to transmit cells in buffers though one output port. We analyzed 4 cell service scheduling algorithms with dynamic round-robinfor each logically separated service line of a single buffer, in which buffers have the respective weighted values and 3 classes on mixed traffic which characteristized by traffic descriptor. In simulation, using SIMCRIPT II.5., we model the VBR and the ABR traffics as ON/OFF processes, and the CBR traffic as a Poisson processes. As the results of analysis according to the proposed buffer management mechanism and cell service algorithm, we have found that the required QoS of each VC can be quaranteed depends on a scale of weighted values allocated to buffers that changed the weighted values, and cell scheduling algorithm.

• The Korean Journal of Physiology and Pharmacology
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• 제24권6호
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• pp.493-502
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• 2020

Apigenin, a naturally occurring flavonoid, is known to exhibit significant anticancer activity. This study was designed to determine the effects of apigenin on two malignant mesothelioma cell lines, MSTO-211H and H2452, and to explore the underlying mechanism(s). Apigenin significantly inhibited cell viability with a concomitant increase in intracellular reactive oxygen species (ROS) and caused the loss of mitochondrial membrane potential (ΔΨm), and ATP depletion, resulting in apoptosis and necroptosis in monolayer cell culture. Apigenin upregulated DNA damage response proteins, including the DNA double strand break marker phospho (p)-histone H2A.X. and caused a transition delay at the G₂/M phase of cell cycle. Western blot analysis showed that apigenin treatment upregulated protein levels of cleaved caspase-3, cleaved PARP, p-MLKL, and p-RIP3 along with an increased Bax/Bcl-2 ratio. ATP supplementation restored cell viability and levels of DNA damage-, apoptosisand necroptosis-related proteins that apigenin caused. In addition, N-acetylcysteine reduced ROS production and improved ΔΨm loss and cell death that were caused by apigenin. In a 3D spheroid culture model, ROS-dependent necroptosis was found to be a mechanism involved in the anti-cancer activity of apigenin against malignant mesothelioma cells. Taken together, our findings suggest that apigenin can induce ROS-dependent necroptotic cell death due to ATP depletion through mitochondrial dysfunction. This study provides us a possible mechanism underlying why apigenin could be used as a therapeutic candidate for treating malignant mesothelioma.

• Journal of Microbiology and Biotechnology
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• 제33권12호
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• pp.1576-1586
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• 2023

Vaccination is the most effective method for preventing the spread of the influenza virus. Cell-based influenza vaccines have been developed to overcome the disadvantages of egg-based vaccines and their production efficiency has been previously discussed. In this study, we investigated whether treatment with forskolin (FSK), an adenylyl cyclase activator, affected the output of a cell-based influenza vaccine. We found that FSK increased the propagation of three influenza virus subtypes (A/H1N1/California/4/09, A/H3N2/Mississippi/1/85, and B/Shandong/7/97) in Madin-Darby canine kidney (MDCK) cells. Interestingly, FSK suppressed the growth of MDCK cells. This effect could be a result of protein kinase A (PKA)-Src axis activation, which downregulates extracellular signal-regulated kinase (ERK)1/2 activity and delays cell cycle progression from G1 to S. This delay in cell growth might benefit the binding and entry of the influenza virus in the early stages of viral replication. In contrast, FSK dramatically upregulated ERK1/2 activity via the cAMP-PKA-Raf-1 axis at a late stage of viral replication. Thus, increased ERK1/2 activity might contribute to increased viral ribonucleoprotein export and influenza virus propagation. The increase in viral titer induced by FSK could be explained by the action of cAMP in assisting the entry and binding of the influenza virus. Therefore, FSK addition to cell culture systems could help increase the production efficiency of cell-based vaccines against the influenza virus.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제27권8C호
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• pp.803-811
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• 2002

Asynchronous Transfer Mode-Passive Optical Network(ATM-PON) Technology is one of the best solutions for implementation of broadband access network. In this paper, we propose a new Dynamic Bandwidth Allocation (DBA) algorithm for ATM-PON systems. The DBA is a key technique for data traffic management. DBA has been studied widely to allow ATM-PON to transport data traffic cost-effectively and efficiently, and currently a hot standardization issue in Full Service Access Network(FSAN) and ITU-T. The proposed DBA algorithm efficiently manages the user traffics according to their service categories. Performance of the proposed algorithm, in aspect of Cell Transfer Delay(CTD) and Cell Delay Variation(CDV), is evaluated using computer simulation.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제13권6호
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• pp.1065-1071
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• 2009

Satellite application services can be divided into realtime services like voice communications and non-real time services like traditional data communications. To support both types of services on the same On-Board Switching(OBS), a scheduler which depends on their service classes is required. A fixed priority scheduling policy has a starvation problem. In this paper we propose a scheduling scheme based on premium and age. Premium is a fixed value which is given to a certain class of services. Age is another parameter of the scheduling policy and it will be increased by one for every scheduling cycle. The scheme we propose chooses a packet which has the largest sum of its age and premium. Simulation results indicate that the proposed approach shows better performance in both average cell delay and std-dev of cell delay for the lower class of service. There is no staying in infinite starvation state.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제19권1호
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• pp.159-169
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• 1994

A multichannel optical slotted ring network is designed using a wavelength division multiplexing(WDM) technique and photonic packet switching devices. The electronics speed bottleneck is removed out of the ring, which allows utilization of the full bandwidth for the optical fiber transmission medium. The ring channel adopts a slotted ring concept with a destination cell remove strategy for the eing access mechanism. The slot size in the ring is selected as the same as that of ATM based cell in order to be used as B-ISDN Access Networks. In this paper, we devised a mathematical method to measure the average transfer delay characteristics of the network. The analytical method turned out to yield accurate results over a broad range of parameters in comparison to simulation results. From the study, we observed the average transfer delay of the network as the network parameters vary.

• Journal of the Korean Society of Radiology
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• 제11권3호
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• pp.147-151
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• 2017

Potentially lethal damage repair (PLDR) in HFL-I was investigated by delayed plating experiments. The surviving fraction data were fitted to the linear Quadratic equation ($LogSn=-n{\gamma}({\alpha}d+{\beta}d^2$) where ${\gamma}=1$ for immediate plating). And a repair factor ${\gamma}$ was developed to compare survival for immediate and delayed plating. When we only took into account the repair factor of PLDR ${\gamma}$ which was derived from the delay assay, the cell survival response th fractionated carbon ion irradiation was not fully matched. This gap suggested that consideration of another repair process is necessary. So this suggests that the various repair process plays an important role in the fractionated irradiations.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제32권8A호
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• pp.820-826
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• 2007

This paper proposes an enhanced degree computationless modified Euclid's(E-DCME) algorithm and its architecture for Reed-Solomon decoders. The proposed E-DCME algorithm has shorter critical path delay that is $T_{mult}+T_{add}+T_{mux}$ compared with the existing modified Euclid's algorithm and the degree computationless modified Euclid's(DCME) algorithm since it uses new initial conditions. The proposed E-DCME architecture employing a systolic array requires only 2t-1 clock cycles to solve the key equation without initial latency. In addition, the E-DCME architecture consisting of 3t basic cells has regularity and scalability since it uses only one processing element. The E-DCME architecture using the $0.18{\mu}m$ Samsung standard cell library consists of 18,000 gates.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.101-104
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• 2000

Nowadays, the issue of congestion control in high-speed communication networks becomes critical in view of the bandwidth-delay products for efficient data flow. In particular, the fact that the congestion is often accompanied by the data flow from the high-speed link to low-speed link is important with respect to the stability of closed-loop congestion control. The Virtual-Connection Network (VCN) in Gigabit Ethernet networks is a packet-switching based network capable of implementing cell- based connection, link-by-link flow-controlled connection, and single- or multi-destination virtual connections. VCN described herein differ from the virtual channel in ATM literature in that VCN have link-by-link flow control and can be of multi-destination. VCNs support both connection-oriented and connectionless data link layer traffic. Therefore, the worst collision scenario in Ethernet CSMA/CD with virtual collision brings about end-to-end delay. Gigabit Ethernet networks based on CSMA/CD results in non-deterministic behavior because its media access rules are based on random probability. Hence, it is difficult to obtain any sound mathematical formulation for congestion control without employing random processes or fluid-flow models. In this paper, an analytical method for the design of a congestion control scheme is proposed based on Smith＇s principle to overcome instability accompanied with the increase of end-to-end delays as well as to avoid cell losses. To this end, mathematical analysis is provided such that the proposed control scheme guarantees the performance improvement with respect to bandwidth and latency for selected network links with different propagation delays. In addition, guaranteed bandwidth is to be implemented by allowing individual stations to burst several frames at a time without intervening round-trip idle time.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제39B권3호
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• pp.143-150
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• 2014

In this paper, we propose an energy efficient and delay guaranteed node scheduling scheme inspired by biological systems, which have gained considerable attention as a computing and problem solving technique. With the identification of analogies between cellular signaling systems and WSN systems, we formulate a new mathematical model that considers the networking challenges of WSNs. The proposed bio-inspired algorithm determines the state of the sensor node, as required by each application and as determined by the local environmental conditions and the states of the adjacent nodes. A control analysis shows that the proposed bio-inspired scheme guarantees the system stability by controlling the parameters of each node. Simulation results also indicate that the proposed scheme provides significant energy savings, as well as reliable delay guarantees by controlling the states of the sensor nodes.