• Journal of Korean Institute of Industrial Engineers
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• v.21 no.1
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• pp.103-118
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• 1995

This paper is concerned with developing flow control method for a dynamic multistage manufacturing system with interstage buffers and unreliable machines. For the effective control of proposed manufacturing system, the three-level hierarchical scheme is introduced. At the top level, we collect the system data and then, design the buffer sizes and hedging points. Short-term production rates are calculated at the middle level. At the bottom level, actual dispatching times are determined by Clear the Largest Buffer Level rule. The control method utilizes the material and the space in the buffers to alleviate the propagation of a failure to other machines in the system and keeps the production close to demand. Finally, a numerical example is provided to illustrate the mathematical control method developed and implemented in a dynamic manufacturing environment.

• Journal of Internet Computing and Services
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• v.8 no.1
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• pp.15-23
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• 2007

Wireless LAN (IEEE 802.11) uses traditional TCP for reliable data transmission, But it brings the unintentional packet loss which is not congestion loss caused by handoff, interference, and fading in wireless LAN. In wireless LAN, TCP experiences performance degradation because it consumes that the cause of packet loss is congestion, and it decrease the sending rate by activating congestion control algorithm. This paper analyzes that correlation of throughput and buffer size for wireless buffer tuning. We find MBT (Maximum Buffer Threshold) which does not increase the throughput through the analysis, For calculation of MBT, we experiment the throughput by using high volume music data which is creased by real-time performance of piano. The experiment results is shown that buffer tuing based on MBT shows 20.3%, 21.4%, and 45.4% throughput improvement under 5ms RTT, 10ms RTT, and 20ms RTT, respectively, comparing with the throughput of operation system default buffer size, In addition, we describe that The setting of TCP buffer size by exceeding MBT does not have an effect on the performance of TCP.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.314-322
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• 2004

The production of a glucan was affected by the concentration of ions and buffer solutions, and nutrients in an oral cavity. In this study, the effects of ions and buffer solutions on the mRNA expression of gtfD gene in Streptococcus mutans, an important causative agent of dental caries, were investigated by Fluorescent in situ hybridization(FISH). At first, ions and buffer solutions had little effect on the multiplication of Streptococcus mutans. The green fluorescence according to the mRNA expression of gtfD gene was detected in the BHI broth containing 1% sucrose. The intensities of the green fluorescence were strong at 0.25mM of $CaCl_2$. Little fluorescence was detected by the addition of KCl, except far 10mM KCl at which fluorescence intensities were similar to those of the control. Fluorescence intensities were weak at each concentration of $MgCl_2$ when compared to the control. As for buffer solutions, fluorescence intensities were similar to those of the control at each concentration of buffer solutions, except that they were little detected at 100mM of potassium phosphate.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11S
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• pp.3269-3277
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• 1999

To promote the inclusion of end-to-end congestion control in the design of future protocols using best-effort traffic, we propose a router mechanism, Extended FRED(ex-FRED). In this paper, we catagorize the TCP controlled traffics into robust and fragile traffic and discuss several unfairness conditions between them caused by the diverse applications. For example, fragile traffic from bursty application cannot use its fair share due to their slow adaptation. Ex-FRED modifies the FRED(Fair Random Early Drop), which can show wrong information due to the narrow view of actual buffer. Therefore, Ex-FRED uses per-flow accounting in larger virtual buffer to impose an each flow a loss rate that depends on the virtual buffer use of a flow. The simulation results show that Ex-FRED uses fair share and has good throughput.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.4
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• pp.784-789
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• 2007

This paper presents an implementation of a new type of architecture to improve an overflow problem on the network buffer. Each receiver channel of network system stores the message in its own buffer. If some receiver channel receives many messages, buffer overflow problem may occur for the channel. This paper proposes a network controller that implements a receiver channel with shared-memory to save all of the received messages from the every incomming channels. The proposed architecture is applied to ARINC-429, a real-time control network for commercial avionics system. For verifying performance of the architecture, ARINC-429 controller is designed using a SOPC platform, designed by Verilog and targeted to Xilinx Virtex-4 with a built-in PPC405 core.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.2
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• pp.143-149
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• 2010

Bandwidth and Buffer are critical network resources to determine the end-to-end quality of service. In this paper, we investigate several techniques on bandwidth and buffer management and classify them according to the types they used for controlling the throughput of a TCP/IP network. Moreover, in this paper, it present a new approach for modeling the active bandwidth and buffer control mechanisms for TCP/IP networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5A
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• pp.514-520
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• 2004

In WDM networt a WDM buffer is one of essential elements for realizing all-optical packet switching system. In this paper, we propose and demonstrate a single loop type all-optical WDM buffer system. The proposed one consists of NOLM and feedback loop, and provides more than 40 turns buffering (more than 20${\mu}\textrm{s}$) for single input pulse (1550nm, width: 20㎱) before selected by control signal pulse (1553nm, width: 30㎱).

• Journal of Environmental Health Sciences
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• v.30 no.2
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• pp.79-83
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• 2004

The oxidative degradation of BPA with laccase from Trametes versiclor was conducted in a closed, temperature controlled system containing acetate buffer for pH control. The effects of medium pH, buffer concentration, temperature and mediator on degradation of BPA were investigated. The inactivation of the enzyme by temperature and reaction product was also studied. The optimal pH for BPA degradation showed about 5. Buffer concentration did not affect BPA degradation. On the other hand, the enzyme stability was higher at low concentration buffer(25 mM). Temperature rise increased the degradation rate of BPA up to 45$^{\circ}C$. The valuable mediator of laccase for BPA was ABTS. Elevated temperature and reaction product irreversibly inactivated the enzyme.

• Journal of the Korean Ceramic Society
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• v.44 no.12
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• pp.727-732
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• 2007

In order to fabricate a highly performing cathode for low-temperature type solid oxide fuel cells working at below $700^{\circ}C$, electrode microstructure control and electrode polarization measurement were performed with an electronic conductor, $La_{0.8}Sr_{0.2}MnO_3$ (LSM) and a mixed conductor, $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3$(LSCF). For both cathode materials, when $Sm_{0.2}Ce_{0.8}O_2$ (SDC) buffer layer was formed between the cathode and yttria-stabilized zirconia (YSZ) electrolyte, interfacial reaction products were effectively prevented at the high temperature of cathode sintering and the electrode polarization was also reduced. Moreover, cathode polarization was greatly reduced by applying the SDC sol-gel coating on the cathode pore surface, which can increase triple phase boundary from the electrolyte interface to the electrode surface. For the LSCF cathode with the SDC buffer layer and modified by the SDC sol-gel coating on the cathode pore surface, the cathode resistance was as low as 0.11 ${\Omega}{\cdot}cm^2$ measured at $700^{\circ}C$ in air atmosphere.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.12
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• pp.9-24
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• 1995

In this paper, we proposed and analysed two kinds of priority control mechanism to archive the cell loss rate requirement and the delay requirement of each class. The service classes of our concern are the high time priority class(class 1) and the high loss priority class(class 2). Two kinds of priority control mechanism is divided by the method of storing the arriving class 2 cell in buffer on case of buffer full. The first one is the method which discarding the arriving class 2 cell, the second one is the mothod which storing the arriving class 2 cell on behalf of pushing out the class 1 cell in buffer. In the proposed priority schemes, one cell of the class 1 is transmitted whenever the maximum K cells of the class 2 is transmitted on case of transmitting the class 1 cell and the class 2 cell sequentially. In this paper, we analysed the cell loss rate and the mean cell delay for each class of the proposed priority scheme by using the Markov chain. The analytical results show that the characteristic of the mean cell delay becomes better for the class 1 cell and that of the cell loss rate becomes better for the class 2 cell by selecting properly the cell transfer ratio according to the condition of input traffic.