• Biotechnology and Bioprocess Engineering:BBE
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• 제10권4호
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• pp.304-308
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• 2005

The response of IPTG induction was investigated through the monitoring of the alkali consumption rate and buffer capacity during the cultivation of recombinant E. coli BL21 (DE3) harboring the plasmid pRSET-LacZ under the control of lac promoter. The rate of alkali consumption increased along with cell growth, but declined suddenly after approximately 0.2 h of IPTG induction. The buffer capacity also declined after 0.9 h of IPTG induction. The profile of buffer capacity seems to correlate with the level of acetate production. The IPTG response was monitored only when introduced into the mid-exponential phase of bacterial cell growth. The minimum concentration of IPTG for induction, which was found out to be 0.1 mM, can also be monitored on-line and in-situ. Therefore, the on-line monitoring of alkali consumption rate and buffer capacity can be an indicator of the metabolic shift initiated by IPTG supplement, as well as for the physiological state of cell growth.

• Nuclear Engineering and Technology
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• 제38권6호
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• pp.483-488
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• 2006

Highly radioactive waste is placed in metal canisters embedded in dense clay termed buffer. The radioactive decay is associated with heat production, which causes degradation of the buffer and thereby time-dependent loss of its waste-isolating potential. The buffer is prepared by compacting air-dry smectite clay powder and is initially not fully water saturated. The evolution of the buffer starts with slow wetting by uptake of water from the surrounding rock followed by a long period of exposure to heat, pressure from the rock and chemical reactants. It can be described by conceptual and theoretical models describing processes related to temperature (T), hydraulic (H), mechanical (M) and chemical performance (C). For temperatures below 90 C more than 75 % of the smectite will be preserved for 100 000 years but cementation may reduce the excellent performance of the buffer to a yet not known extention.

• 방사성폐기물학회지
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• 제20권2호
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• pp.185-192
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• 2022

A compacted bentonite buffer is a major component of engineered barrier systems, which are designed for the disposal of high-level radioactive waste. In most countries, the target temperature required to maintain safe functioning is below 100℃. If the target temperature of the compacted bentonite buffer can be increased above 100℃, the disposal area can be dramatically reduced. To increase the target temperature of the buffer, it is necessary to investigate its properties at temperatures above 100℃. Although some studies have investigated thermal-hydraulic properties above 100℃, few have evaluated the water suction of compacted bentonite. This study addresses that knowledge gap by evaluating the water suction variation for compacted Korean bentonite in the 25-150℃ range, with initial saturations of 0 and 0.22 under constant saturation conditions. We found that water suction decreased by 5-20% for a temperature increase of 100-150℃.

• 대한산업공학회지
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• 제14권2호
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• pp.115-129
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• 1988

This paper discusses an analytical method to derive the efficiency and the average storage level of an unreliable two-machine, two-stage automatic transfer line with interstage buffer storage. Extensive numerical experiments and simulations are also conducted to see the behavior of the system under the wide range of parameter values as well as various distributions.

• 전자공학회논문지C
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• 제34C권9호
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• pp.43-52
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• 1997

Processors using the superscalar rchitecture can achieve high performance by executing multipel instructions in a clock cycle. It is made possible by having multiple functional units and issuing multiple instructions to functional units simultaneously. But instructions can be dependent on one another and these dependencies prevent some instructions form being issued at the same cycle. In this paper, we designed an issue unit of a superscalar RISC microprocessor that can issue four instructions per cycle. The issue unit receives instructions form a prefetch unit, and issues them in order at a rate of as high as four instructions in one cycle for maximum utilization of functional units. By using an instruction buffer, the unit decouples instruction fetch and issue to improve instruction ussue rate. The issue unit is composed of an instruction buffer and an instruction decoder. The instruction buffer aligns and stores instructions from the prefetch unit, and sends the earliest four available isstructions to the instruction decoder. The instruction decoder decodes instructions, and issues them if they are free form data dependencies and necessary functional units and rgister file prots are available. The issue unit is described with behavioral level HDL (lhardware description language). The result of simulation using C programs shows that instruction issue rate is improved as the instruction buffer size increases, and 12-entry instruction buffer is found to be optimum considering performance and hardware cost of the instruction buffer.

• International Journal of Computer Science & Network Security
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• 제21권12호
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• pp.207-212
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• 2021

A buffer overflow attack is carried out to subvert privileged program functions to gain control of the program and thus control the host. Buffer overflow attacks should be prevented by risk managers by eradicating and detecting them before the software is utilized. While calculating the size, correct variables should be chosen by risk managers in situations where fixed-length buffers are being used to avoid placing excess data that leads to the creation of an overflow. Metamorphism can also be used as it is capable of protecting data by attaining a reasonable resistance level [1]. In addition, risk management teams should ensure they access the latest updates for their application server products that support the internet infrastructure and the recent bug reports [2]. Scanners that can detect buffer overflows' flaws in their custom web applications and server products should be used by risk management teams to scan their websites. This paper presents an experiment of buffer overflow vulnerability and attack. The aims to study of a buffer overflow mechanism, types, and countermeasures. In addition, to comprehend the current detection plus prevention approaches that can be executed to prevent future attacks or mitigate the impacts of similar attacks.

• Nuclear Engineering and Technology
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• 제55권11호
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• pp.4173-4180
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• 2023

The stability of engineered barriers in high-level radioactive waste disposal systems can be influenced by the decay heat generated by the waste. This study focuses on the thermal analysis of various canister designs to effectively lower the maximum temperature of the engineered barrier. A numerical model was developed and employed to investigate the heat dissipation potential of copper rings placed across the buffer. Various canister designs incorporating copper rings were presented, and numerical analysis was performed to identify the design with the most significant temperature reduction effect. The results confirmed that the temperature of the buffer material was effectively lowered with an increase in the number of copper rings penetrating the buffer. Parametric studies were also conducted to analyze the impact of technical gaps, copper thickness, and collar height on the temperature reduction. The numerical model revealed that the presence of gaps between the components of the engineered barrier significantly increased the buffer temperature. Furthermore, the reduction in buffer temperature varied depending on the location of the gap and collar. The methods proposed in this study for reducing the buffer temperature hold promise for contributing to cost reduction in radioactive waste disposal.

• 산업공학
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• 제15권3호
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• pp.316-324
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• 2002

Automated Guided Vehicles are widely used as an essential material handling system for FMS to provide flexibility and efficiency. We suggest a new dispatching rule based on priority function which considers urgency and empty vehicle travel time under finite buffer capacity. We evaluate the performance of the proposed rule by comparing the performance of Shortest Travel Time/Distance(STT/D) rule in terms of machine utilization, throughput and WIP level using simulation. The simulation results show that the suggested dispatching rule is robust and provides better machine utilization, throughput with comparable WIP level compared to STT/D rule.

• 한국통신학회논문지
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• 제22권6호
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• pp.1334-1342
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• 1997

The future data communications are expected to support the various andcomplex services withmultimedia. So thispaper has focused on the multimedia synchronization problem which has important position in multimedia presentation. Firstly, this paper consider the suitable layer for multimedia synchronization in the communication structure as transport layer or upper ones, in which we propose synchronization mechanism using fixed length buffer with bufer-lever or upper ones, in which we propose synchronization mechanism using fixed length bufer with buffer-level. The proposed mechansim also supports intra-and inter-media synchronization among media. Through simulation, we prove our analysis of the fixed-length buffersize that theproposed mechanism can provide. Also we show comparisons between our mechanism and other scheme.

• 한국경영과학회지
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• 제21권2호
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• pp.17-33
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• 1996

Automatic transfer defined as an integrated system with a number of workstations, interstation storage buffers, automatic device and a control system, play a major role in ass production systems. Due to high capital investment needed for an automatic transferline, greater care should be taken in its design so as to maximize the system performance. One may to control the system performance is to control buffer storage. To control the interstation work-in-process inventory, we propose dual limit switches which control the buffer storage with two parameters, R and r. Under the policy, proceding station is forced down when the inventory level in the buffer reaches R until the level falls to r. For the model developed, we analyze the system characteristics and find the optimal control parameters with a serach procedure.