• The KIPS Transactions:PartA
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• v.15A no.6
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• pp.309-316
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• 2008

The mission-critical engagement control computer for air defense has to maintain its operation without any fault for a long mission time. The mission performed by large-scale and complex embedded software is extremely critical in terms of dependability and safety of computer system, and it is very important that engagement control computer has high reliability. The engagement control computer was implemented using four processors. The distributed computer composed of four processors quarantees the dependability and safety, and ASR fault-tolerant technique applied to each processor guarantees the reliability. In this paper, the mechanism and performance of ASR fault-tolerant technique are analysed. And MTBF, reliability, availability, and cost-effectiveness for ASR, DMR and TMR techniques applied to the engagement control computer are analysed. The mission-critical engagement control computer using software-based ASR fault-tolerant technique provides high reliability and fast recovery time at a low cost. The mission reliability of the engagement control computer using ASR technique in 4 processors board is almost same the reliability of the computer using TMR technique in 6 processors board. ASR technique is most suitable to the mission-critical engagement control computer.

• Environmental and Resource Economics Review
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• v.31 no.4
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• pp.909-930
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• 2022

Although the electricity tariff for each customer class in Korea has an institutional basis which can be linked to cost fluctuations caused by the increase in fuel cost, there is a situation in which it cannot be raised in a timely manner, considering the national economic burden such as inflation. There can be some disagreements about unconditionally raising electricity rates when cost increases occur. It is, however, well known that Korean domestic electricity rates are very low around the world and are in an environment in which rates are not easily adjusted. Moreover, as Korean electricity rates cannot be easily raised due to various factors, domestic electricity rates for each customer class itself have not delivered a desirable price signal for power consumption. Based on historical data such as fuel costs and power production by power source from 2017 to 2020, this study estimated how much power consumption would change if electricity rates were adjusted in 2030 and price signal distortion was resolved. As a result of the estimation, power consumption will be reduced by 9,000 GWh if the current electricity bill is adjusted to a level which can be 100% recovered even with the supply cost alone. This led to a reduction of about 3.82 million CO₂tons of greenhouse gas emissions in the Korean power sector.

• Journal of Embryo Transfer
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• v.26 no.3
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• pp.153-158
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• 2011

This study was performed in order to simplify the operation and minimize stress of donor and be readily available in the field with low cost and high quality embryos using the Direct Embryo Collection (DEC). Donors, at random stages of the estrous cycle, received a CIDR. 7 days later, 200 mg FSH was treated with 40, 30, 20, 10 mg FSH levels in declining doses twice daily by intramuscular injection for 4 days. On the 3rd day administration of FSH, 25 mg $PGF_2{\alpha}$ was administered and CIDR was withdrawn. After FSH injections were complete, donors were artificially inseminated twice at 12 hr intervals. The donor cattle received 250 ${\mu}g$ GnRH at time of 1 st insemination and embryos were recovered 8 days after the 1st insemination. Embryo collection from superovulated donors was performed to flushing by non-surgical methods of 3-way, 2-way and DEC (l-way). The average number of recovered embryos were 11.25${\pm}$0.63, 12.5${\pm}$0.65 and 11.75${\pm}$0.48 from operations of 3-way, 2-way and DEC methods, respectively. There were no significant differences among the embryo collection methods. Also, The average number of transferable embryos were 6.25${\pm}$0.48, 7.25${\pm}$0.48 and 7.25${\pm}$0.63 from each embryo collection procedures. The number of transferable embryos was no differences among the 3-way, 2-way and DEC methods, respectively. Meanwhile, the ratio of transferable embryos for all recovered embryos from DEC methods was higher as 61.7 % than 55.6 %, 58 % from methods of 3-way, 2-way. And the flushing solution required for recovering embryos by DEC method was significantly lower as 0.28${\pm}$0.32 1 than 1.8${\pm}$0.12 1, 1.75${\pm}$0.10 1 from 3-way, 2-way methods (p<0.05). Also, the time required for recovering embryos by DEC methods was significantly lower as 27${\pm}$2 min than 51${\pm}$3, 45${\pm}$2 min, respectively (p<0.05). In conclusion, these results suggest that DEC method for embryo collection may be effectively used for production of in vivo embryos using less flushing solution and, it might be effectively available in the field compared to conventional embryo recovery methods using 3-way or 2-way balloon catheter.

• Journal of Chest Surgery
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• v.24 no.11
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• pp.1058-1067
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• 1991

High potassium cardioplegia is a widely accepted procedure to enhance myocardial protection from ischemic injuries associated with open heart surgery. Maintaining optimum osmolarity of the cardioplegic solution is one of the required conditions for an ideal cardioplegic solution Albumin is an frequently added component for maintaining optimum osmolarity of clinically used cardioplegic solutions. But the source of albumin is human blood so that the supply is limited and the cost of manufacturing is relatively high. Recently there are moves to minimized the use of blood product for fear of blood-associated infections or immunological disorders. In this experiment, we substituted mannitol or glucose for albumin added to the cardioplegic solution which has been used at the Wonju Medical College, To determine whether addition of mannitol or glucose instead of albumin in the cardioplegic solution can produce satisfactory myocardial protection during ischemia, three different groups of isolated rat heart perfused by modified Langendorff technique were studied. Wonju Cardioplegic Solution was selected as a standard high potassium[18mEq/L of K+] cardioplegic solution. Three kinds of cardioplegic solution were made by modifying the composition maintaining the same osmolarity[339$\pm$1mOsm/Kg] Isolated rat heart were perfused initially with retrograde nonworking mode and then changed to working mode. After measuring the heart rate, systolic aortic pressure, aortic flow, coronary flow, ischemic arrest by aorta cross clamp and cardioplegia was made maintaining the temperature of water jacket at 10oC. The heart was rewarmed and reperfused after 60min of ischemic arrest with intermittent cardioplegia at the 30min interval. The time to return of heart beat and the time required to get. Regular heart beat were observed after reperfusion. The recovery rate of the functional variables-heart rate, systolic aortic pressure, aortic flow, coronary flow and cardiac output were calculated and compared among the three groups of different cardioplegia-albumin, mannitol, and glucose. The wet weight and dry weight was measured and the water content of the heart as figured out for comparison. The time to return of heart beat was fastest in the albumin group, The functional recovery rates were best in the albumin group also. In the above conditions, albumin was the best additive to the cardioplegic solution compared to the mannitol or glucose.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.3
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• pp.178-192
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• 2006

The buffer overflow attack is the single most dominant and lethal form of security exploits as evidenced by recent worm outbreaks such as Code Red and SQL Stammer. In this paper, we propose microarchitectural techniques that can detect and recover from such malicious code attacks. The idea is that the buffer overflow attacks usually exhibit abnormal behaviors in the system. This kind of unusual signs can be easily detected by checking the safety of memory references at runtime, avoiding the potential data or control corruptions made by such attacks. Both the hardware cost and the performance penalty of enforcing the safety guards are negligible. In addition, we propose a more aggressive technique called corruption recovery buffer (CRB), which can further increase the level of security. Combined with the safety guards, the CRB can be used to save suspicious writes made by an attack and can restore the original architecture state before the attack. By performing detailed execution-driven simulations on the programs selected from SPEC CPU2000 benchmark, we evaluate the effectiveness of the proposed microarchitectural techniques. Experimental data shows that enforcing a single safety guard can reduce the number of system failures substantially by protecting the stack against return address corruptions made by the attacks. Furthermore, a small 1KB CRB can nullify additional data corruptions made by stack smashing attacks with only less than 2% performance penalty.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.2
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• pp.19-24
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• 2007

With recent advancement of high-speed, multi-gigabit data transmission capabilities, serial links have been more widely adopted in industry than parallel links. Since the parallel link design forces its transmitter to transmit both the data and the clock to the receiver at the same time, it leads to hardware's intricacy during high-speed data transmission, large power consumption, and high cost. Meanwhile, the serial links allows the transmitter to transmit data only with no synchronized clock information. For the purpose, clock and data recovery circuit becomes a very crucial key block. In this paper, a 5.4Gbps half-rate bang-bang CDR is designed for the applications of high-speed graphic DRAM interface. The CDR consists of a half-rate bang-bang phase detector, a current-mirror charge-pump, a 2nd-order loop filter, and a 4-stage differential ring-type VCO. The PD automatically retimes and demultiplexes the data, generating two 2.7Gb/s sequences. The proposed circuit is realized in 66㎚ CMOS process. With input pseudo-random bit sequences (PRBS) of $2^{13}-1$, the post-layout simulations show 10psRMS clock jitter and $40ps_{p-p}$ retimed data jitter characteristics, and also the power dissipation of 80mW from a single 1.8V supply.

• Journal of Korean Society of Rural Planning
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• v.22 no.2
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• pp.19-29
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• 2016

Disasters that occur most frequently in rural areas are drought, flood, damages from wind and cold weather. Among these, damages from storm and flood and drought are the main disasters and recently, these are occurring on a large scale due to unusual weather conditions. Under such circumstances, projects and researches on disasters in rural areas are under way but they are mostly targeting one area or making approaches focusing on repair facilities, maintenance project of facilities in small streams, and disaster management, so there have not been enough studies on the current status of overall damaged facilities in the rural areas. Against this backdrop, through the analysis of the current status of damaged facilities due to storm and flood in rural areas, this study aims to provide base data for policies needed for disaster recovery planning and maintenance work of rural areas. For the analysis of damaged facilities due to storm and flood in rural areas, using the annual report on disasters issued by Ministry of Public Safety and Security and based on the occurrence rate of estimated damage in each city and district for the past 10 years(2004~2013), 8 areas with the highest number of occurrence and cost of damage were found from each province and target areas were selected. Then, regarding the selected target areas, the General Plan for Reducing Damages from Storm and Flood, which is the report on top-level plan for preventing disasters, was secured and the current status of damaged facilities were analyzed. After organizing the analysis of current status, the tendency of damaged facilities due to storm and flood in rural areas, the items of damaged facilities depending on the types of storm and flood damages, and risk factors were suggested. Based on this result, in order to generalize the results of follow-up researches, it is thought that disaster recovery planning and establishing the system of remodeling items necessary for maintenance work would be possible by analyzing damage investigation items recorded in additional researches on rural areas, researches on natural disasters, and recovery plan instructions and by conducting on-site investigation on the damaged villages from storm and flood in rural areas.

• Resources Recycling
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• v.29 no.4
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• pp.15-30
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• 2020

Recently, it is increasing a amount of installed solar-cell rapidly, and end-of-life photovoltaic(ELP) modules are generated in according to the reduction of cell efficiency largely. Recycling of ELP modules are begun at an advanced nation already, but there are bring about environmental contamination and resource recovery problems owing to not treated ELP modules because of economic cost completely. First of all, there were researched basic study for treatment conditions of used solar cell inspection, dismantling of aluminum frame, crushing / grinding & separation of tempered glass, removal of back sheet & EVA film, leaching & precipitation recovery of valuable metals and treatment of waste water. Therefore, we establish optimum conditions through carried out of designed apparatus, installation of equipment, test operation & trouble shooting in scale of 1ton/day pilot plant test. Following to economic review, it does have the economic efficiency until to the case of tempered glass recovery, but does not have the economic value in case of total processes until to recover the valuable metals. However, there are guaranteed economic value if we are gained a large amount of the expenses through EPR supported system. It was confirmed the commercialized possibility of ELP modules recycling if there were established on the collecting ELP modules, reusing criteria, economical technology, enactment of directives and enforcement of EPR supported system efficiently.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.759-765
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• 2012

As the biodiesel production is increasing rapidly, the crude glycerol, which is principal by-product of biodiesel production, has also been generated in a large amount. Many research studies on value-added utilization of glycerol are under investigation. 1,3-Propandiol is a promising chemical which can be produced from fermentation of glycerol because the application of 1,3-propanediol is mainly in the production of bio-PTT (Poly(trimethylene terephthalate). However, the cost of downstream processes in the biological production of 1,3-propanediol can make a high portion in the total production cost. This review summarizes the present state of separation processes in each step studied for the removal of impurities and the recovery of 1,3-propanediol from its fermentation broth. Furthermore, ATPE (Aqueous Two Phases Extraction) process is suggested as an attractive alternative for the primary separation process of 1,3-propanediol because ATPE is convenient for the simultaneous removal of microbial cells and impurities such as salts of organic acids and the separation of 1,3-propanediol from fermentation broth.

• Korean Chemical Engineering Research
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• v.49 no.5
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• pp.639-643
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• 2011

Fry-drying of coal slurry is one of the upgrading low rank coal processes. It consists of slurry mixing, slurry dewatering, solvent recovery and briquetting. Cost estimation and economic feasibility are examined for the upgrading low rank coal process based on capacity of 1 million ton/yr. In case that investment costs are $100,000,000, discount rate is 12%, and service life is 20 years, the results of economic analysis are enough to satisfy the evaluation criteria of investment such as IRR, B/C ratio, NPV and discounted payback period. According to sensitivity analysis, investment value are very sensitive to raw material cost and product price. Since the bituminous coal price is currently soaring, it is expected that the investment value will increase more and more.