• The Journal of the Convergence on Culture Technology
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• v.10 no.1
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• pp.411-417
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• 2024

In the event of a disaster, it is essential to establish a disaster recovery plan and disaster recovery system to minimize disruption to major IT infrastructure and provide continuous business services. In the process of building a disaster recovery system, data replication is a key element of data recovery to provide uninterrupted and continuous business services in the event of a disaster. The data replication method can be determined depending on the system configuration environment and disaster recovery goal level. In this paper, we present a method for determining a data replication method suitable for the configuration environment and disaster recovery target level when building a disaster recovery system. In addition, the replication method decision procedure is applied to build a disaster recovery system and analyze the construction results. After establishing the disaster recovery system, a test was conducted to determine whether the service was transferred to the disaster recovery center in a disaster situation and normal service was provided, and the results were analyzed. As a result, it was possible to systematically select the optimal data replication method during the disaster recovery system construction phase. The established disaster recovery system has an RTO of 3.7 hours for service conversion to the disaster recovery center to provide continuous business services, and the disaster recovery level, which was Tier 2, has been improved to the target level within 4 hours of RTO and RPO=0.

• Journal of Power Electronics
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• v.4 no.1
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• pp.39-45
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• 2004

A novel current-fed energy-recovery sustaining driver (CFERSD) for a PDP is proposed in this paper. Its main idea is to recover the energy stored in the PDP or to inject the input source energy to the PDP by using the current source built-up in the energy recovery inductor. This method provides zero-voltage-switching (ZVS) of all main power switches, the reduction of EMI, and more improved operational voltage margins with the aid of the discharge current compensation. In addition, since the current flowing through the energy recovery inductor can compensate the plasma discharge current flowing through the conducting power switches, the current stress through all main power switches can be considerably reduced. Furthermore, it features a low conduction loss and fast transient time. Operations, features and design considerations are presented and verified experimentally on a 1020${\times}$l06mm sized PDP, 50kHz-switching frequency, and sustaining voltage 140V based prototype.

• International Journal of Industrial Entomology and Biomaterials
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• v.14 no.1
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• pp.45-50
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• 2007

Ethanol extract of 20 botanicals in 3 concentrations i.e., 2.5%, 5% and 10% were evaluated for their efficacy to improve reproductive performance of mulberry silkworm (Bombyx mod L.) through feeding botanical enriched mulberry leaves during $2^{nd}$ day of $4^{th}$ age as well as $1^{st}$ and $3^{rd}$ day of $5^{th}$ age larvae. The preliminary screening was done by ranking the botanicals based on influence in most important reproductive contributing parameters such as single cocoon weight, effective rate of rearing, pupation rate, fecundity and recovery of eggs/kg cocoon. Five botanicals viz., Asparagus recemosus, Achyranthes aspera, Tribulus terrestris, Withania somnifera, Parthenium histerophorus ranked first were further evaluated at 8% 5% and 3% concentrations to confirm their effectiveness and standardize effective concentration. Among the rearing parameters, mature larval weight, shell ratio and number of cocoons/kg were not significantly influenced by the treatments. However, reproductive parameters such as effective rate of rearing (wt), pupation rate (%), fecundity (No.) and egg recovery (g)/kg cocoon were significantly (P<0.05) influenced by the botanicals. Higher fecundity and egg recovery were obtained on treatment with Withania somnifera irrespective of concentrations. However at 5% concentration, pupation rate, fecundity as well as egg recovery were found significantly higher than that of other concentrations, confirming its effectiveness for improving reproductive efficiency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.386-387
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• 2006

This study is about the recycling technology of scrap a PCB(printed circuit board) produced in home appliances or automobile industry. And we develop the recycling technology of cooper (Cu)which is contained to leaching solution. In stead of electrolytic collecting in existing sulphuric atmosphere, we apply process using the ammonia solution which is used in economizing energy. So m the process of electrolyzing scrap a PCB through the leaching and separation, we examine the effect of the nickel contained to the solution and the cooper degree of purity which is changed according to current density.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.11
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• pp.5200-5222
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• 2017

The separation of control plane and data plane in Software Defined Network (SDN) makes it flexible to control the network behavior, while also causes some inconveniences to the link failure recovery due to the delay between fail point and the controller. To avoid delay and packet loss, pre-defined backup paths are used to reroute the disrupted flows when failure occurs. However, it may introduce large overhead to build and maintain these backup paths and is hard to dynamically construct backup paths according to the network status so as to avoid congestion during rerouting process. In order to realize congestion aware fast link failure recovery, this paper proposes a novel method which installs multi backup paths for every link via source routing and per-hop-tags and spread flows into different paths at fail point to avoid congestion. We carry out experiments and simulations to evaluate the performance of the method and the results demonstrate that our method can achieve congestion aware fast link failure recovery in SDN with a very low overhead.

• Journal of the Korean Society for Heat Treatment
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• v.37 no.2
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• pp.79-85
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• 2024

The effects of annealing heat treatment and the addition of Cu element on the shape memory effect of the NiTi-based alloy were investigated by analyzing differential scanning calorimeter results and characterizing recovery rate through 3D scanning after Vickers hardness test. Through 3D scanning of impressions after Vickers hardness test, the strain recovery rates for specimens without annealing treatment and annealed specimens at 400, 450, and 500℃ were measured as 45.96%, 46.76%, 52.37%, and 43.57%, respectively. This is because as the annealing temperature increases, both B19' and NiTi₂ phases, which can impede martensitic transformation, are incorporated within the NiTi matrix. Particularly, additional phase transformation from R-phase to B19' observed in specimens annealed at 400 and 450℃ significantly contributes to the improvement in strain recovery rates. Additionally, the results regarding the Cu element content indicate that when the total content of Ni and Cu is below 49.6 at.%, the precipitation of fine B19' and NiTi₂ phases within the matrix can greatly influence the transformation enthalpy and temperature range, resulting in relatively lower strain recovery rates in NiTi alloys with a small amount of Cu element produced in this study.

• Journal of the Korean institute of surface engineering
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• v.29 no.5
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• pp.338-344
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• 1996

This study was an investigation of plasma-induced damages on silicon substrate in the semiconductor manufacturing technology. The plasma-induced damage level on silicon substrate was analyzed and compared in various plasma etching systems. The analysis methods were therma wave, life-time recovery, SCA (Surface Charge Analyzer) and TRXF (Total Reflection X-ray Fluorescence) measurements, and the measured values were compared for each systems. In the comparison of the values which were obtained by a system that had low life-time recovery, there was not any differences in DC parameters. However, the reflesh time distribution of device of that system had decreased about 10 to 20m sec compared to a system which had high life-time recovery.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.229-231
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• 2001

IPSec is a security protocol suite that provides encryption and authentication services for IP messages at the network layer of the Internet. Key recovery has been the subject of a lot of discussion, of much controversy and of extensive research. Key recovery, however, might be needed at a corporate level, as a from of key management. The basic observation of the present paper is that cryptographic solutions that have been proposed so far completely ignore the communication context. Static systems are put forward fur key recovery at network layer and solutions that require connections with a server are proposed at application layer. We propose example to provide key recovery capability by adding key recovery information to an IP datagram. It is possible to take advantage of the communication environment in order to design key recovery protocols that are better suited and more efficient.

• Journal of Microbiology and Biotechnology
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• v.25 no.6
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• pp.918-929
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• 2015

Microbial enhanced oil recovery (MEOR) is being used more widely, and the biological contributions involved in MEOR need to be identified and quantified for the improvement of field applications. Owing to the excellent interfacial activity and the wide distribution of producing strains in oil reservoirs, lipopeptides have proved to be an essential part of the complex mechanisms in MEOR. In this study, crude lipopeptides were produced by a strain isolated from an indigenous community in an oil reservoir. It was found that crude lipopeptides can effectively reduce the IFT (interfacial tension) to 10^-1~10^-2 mN/m under high salinity without forming stable emulsions, and the wettability of natural sandstone can be enhanced (Amott index, from 0.36 to 0.48). The results of core flooding experiments indicate that an additional 5.2% of original oil in place can be recovered with a 9.5% reduction of injection pressure. After the shut-in period, the wettability of the core, the reduction of injection pressure, and the oil recovery can be improved to 0.63, 16.2% and 9.6%, respectively. In the microscopic flooding experiments, the crude oil in membrane, cluster, and throat states contribute nearly 90% in total of the additional oil recovery, and the recovery of membranestate oil was significantly enhanced by 93.3% after shut in. Based on the results in macro and pore scale, the IFT reduction and the wettability alteration are considered primary contributors to oil recovery, while the latter was more dominant after one shut-in period.

• Membrane Journal
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• v.23 no.3
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• pp.189-203
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• 2013

F-gases, gases containing fluorine such as perfluorocarbons (PFCs), sulfurhexafluoride ($SF_6$), nitrogen trifluoride ($NF_3$) are known to have green house effects. Although the net emission rates of gases containing fluorine are much lower than those of $CO_2$, their contribution to global warming cannot be ignored because of their extremely high global warming potential (GWP). F-gases mainly have been used for a variaty of applications in the semiconductor/LCD processes and in the electric power distribution industry of the national key industry. One of practical solutions of controlling the emission rates of F-gases is to reuse by separation and recovery of F-gases of low concentration from the gases mixtures with nitrogen or air. This work investigates some methods for F-gases recovery and separation around the membrane-based process.