• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.4
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• pp.63-71
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• 2014

As power consumption increases, more power utilities are required to satisfy the demand and consequently results in tremendous cost to build the utilities. Another issue in construction of power utilities to meet the peak demand is an inefficiency caused by surplus power during non-peak time. Therefore, most power company considers power demand management with time-based electricity rate policy which applies different rate over time. This paper considers an optimal machine operation problem under the time-based electricity rates. In TOC (Theory of Constraints), the production capacities of all machines are limited to one of the bottleneck machine to minimize the WIP (work in process). In the situation, other machines except the bottleneck are able to stop their operations without any throughput loss of the whole manufacturing line for saving power utility cost. To consider this problem three integer programming models are introduced. The three models include (1) line shutdown, (2) block shutdown, and (3) individual machine shutdown. We demonstrate the effectiveness of the proposed IP models through diverse experiments, by comparing with a TOC-based machine operation planning considered as a current model.

• Journal of Environmental Science International
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• v.19 no.11
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• pp.1315-1322
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• 2010

A membrane bioreactor (MBR) was designed using polyvinylidene fluoride(PVDF)-type hollow fiber membrane modules with a treatment capacity of 10 ton/day. A pilot plant was installed in a sewage treatment plant and was operated with an intermittent aeration method which avoids any concentration gradient of suspended solids (SS) in the MBR. For continuous operation, the pilot plant was first tested with influent (mixed liquor suspended solid:MLSS of 1000-2000 mg/L) of aeration tanks in the sewage treatment plant. The MBR was pre-treated with washing water, 10% ethanol solution, 5% NaOCl solution and finally washing water, one after another. To demonstrate the effect of the MBR on sewage treatment, compared with conventional activated sludge processes, we investigated the relationships among permeate amount (LMH), change in operation conditions, influent MLSS level and sludge production. It was found that the optimum aeration rate and suction pressure were $0.3\;m^3$/min and 30~31 cmHg, respectively. Under stable conditions in aeration, suction pressure, influent flow rate and drainage, the SS removal efficiency was more than 99.99% even when the MLSS loading rate changes. Compared with conventional activated sludge processes, the MBR was more effective in cost reduction by 27% based on permeate amount and by 51.5% on sludge production.

• Journal of Chest Surgery
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• v.33 no.10
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• pp.792-797
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• 2000

Background : Even though there were developments in various treatment techniques for acute arterial occlusion this disease still has high rate of mortalities and limb amputations. We investigated the combined diseases symptoms location of occlusion type of treatment complication and prognosis in our patients. Meterial and methods: This study recruited 48 patients(42 men, 6 women, mean age 57.7 years) who received the operation from January 1995 toDecember 1998. We investigated the post-operation course via medical record review or telephone interview with patients or their family members. Result: The most common combined diseases were atherosclerosis in 30 patients. other diseases were 17 diabetes mellitus 16 hypertension and 12 atrial firillation. Pain and clod sensation were noticed in all patients paresthesia in 5 patients fibrillation. Pain and cold sensation were noticed in all patients paresthesia in 5 patients and lower extremity paralysis in 11 patients. In 29 patients the time interval from the onset of symptom to admission was over 72 hours and 15 patients were admitted within 24 hours. The distribution of arterial occlusion location was at 28 femoral arteries 14 popliteal arteries and 6 iliac arteries. All the patients were received embolectomy and 5 patients were received additional bypass grafting. Postoperative complications were 12 reocclusions. 6 compartment syndromes 6 skin necrosis and 2 acute renal failure. The mortality rate was 16.7%(8/48) and the amputation rate was 25% Conclusion : This study revealed 25% reocclusion 25% limb amputation and 16.7% mortaliyt. To improve the prognosis of acute lower extrements arterial occlusion early diagnosis and understand the underlying diseases prompt treatment and operation additional operation including interventional radiologic examination and thorough postoperative care would be appreciated.

• Tunnel and Underground Space
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• v.2 no.1
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• pp.177-189
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• 1992

As tunnel becomes longer and larger, TBM has become one of the most popular methods of excavatio in rock. This paper describes the degree of operation the degree of availability and penetration rate of TBM and TBE applied in Namsan roadway tunnelling site. Net penetration rate was 1.62m/hr for TBM and 0.72m/hr for TBE. Net penetration rate showed no direct relation to daily advance or penetration time, but the lower bound of penetration rate could be obtained from the relation with daily advance. For both of TBM and TBE, the degree of operation and the degree of availability were 33.8% and 68.6% respectively. Life time of normal cutter was $310m^3$ for TBM and $194m^3$ for TBE, while that of center and gauge cutter was about $50m^3$. When the two machines were compared, TBM showed 80% higher penetration rate, and 40% shorter life time of cutter.

• Journal of Hydrogen and New Energy
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• v.33 no.5
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• pp.591-597
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• 2022

Recently, technologies for efficient power grid operation have become important due to climate change. For this reason, predicting power demand using deep learning is being considered, and it is necessary to understand the influence of characteristics of each region, industrial structure, and climate. This study analyzed the power demand of New Jersey in US, with a high urbanization rate and a large service industry, and West Virginia in US, a low urbanization rate and a large coal, energy, and chemical industries. Using recurrent neural network algorithm, the power demand from January 2020 to August 2022 was learned, and the daily and weekly power demand was predicted. In addition, the power grid operation based on the power demand forecast was discussed. Unlike previous studies that have focused on the deep learning algorithm itself, this study analyzes the regional power demand characteristics and deep learning algorithm application, and power grid operation strategy.

• KSBB Journal
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• v.13 no.3
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• pp.259-267
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• 1998

Optimal feeding strategies in bioreactor operation of Scutellaria baicalensis G. plant cell culture were investigated to maximize the production of flavone glycosides by using a structured kinetic model which can predict culture growth and flavone glycosides synthesis in a rigorous, quantitative manner. For the production of baicalin and wogonin-7-0-GA, the strategies for glucose feeding into Scutellaria baicalensis G. plant cell culture were proposed based on the model, which are a periodic fed-batch operation with maintenance of cell viability and of specific production rate respectively, and a perfusion operation with maintenance of specific production rate for baicalin and wogonin-7-0-GA. Simulation results showed that the highest volumetric concentration of flavone glycosides was obtained in a periodic fed-batch operation with maintenance of cell viability among all the suggested strategies. In the periodic fed-batch operations, the higher volumetric production of flavone glycosides was achieved compared with that in the perfusion operation. It can be concluded that a periodic fed-batch operation with maintenance of cell viability would be the optimal and practical operating strategy of Scutellaris baicalensis G. plant cell culture for the production of flavone glycosides.

• Membrane Journal
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• v.9 no.4
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• pp.193-201
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• 1999

The object of study were the development of membrane process and the optimization of operation condition for membrane system, which was used the pre-treatment system of tap water treatment in steady of conventional process such as coagulation, sedimentation. The higher steady flux is very important factor, by a suitable pre-treatment and optimization of operating condition such as fouling control, crossflow and backwashing method, in membrane system. So, we were observed the effect of flux decline for membrane used by 4 type ultrafiltration(UF) membrane pre-treatment process, and optimized the operation condition of filtration system under various MWCO(Molecular weight cut-off), operation pressure, linear velocity and temperature to maintain higher flux. From these experiment, we were identified that UF process showed a slower flux decline rate and a higher flux recovery than microfiltration(MF) membrane. The water quality of UF permeate was better than that of MF, and was not effected pre-treatment process. In the operation condition, the rate of flux decline was diminished by a higher linear velocity and operation temperature, lower pressure.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.3
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• pp.588-594
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• 2001

The aim of this paper is to develop the low temperature vacuum dryer, with low initial investments and operating costs, easy operating method and trouble-free operation Usally operations just below atmospheric pressure, as with direct dryers, but some are built for vacuum operation with pressure as low 50 mmHg abs. The lowers the boiling point to $39^{\circ}C$ The experimental data of quantitative analysis for using practically were obtained by the constant drying rate period and reducing drying rate period according to the temperature of hot water which is the experimental parameters of present experiment. As the results, it took about 20 hours for material to reach about 18% of the final moisture content is order to store products for a long time about 450% of the early moisture content at the beginning of drying and maximum drying rate comes to about 0.30 kg/m2hr at about 350% of the moisture content.

• Speech Sciences
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• v.5 no.1
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• pp.105-119
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• 1999

Cleft palate patients have general speech problems with resonance disorders and articulation disorders. The aim of this study is to find the aerodynamic and acoustic characteristics of the nasalization in cleft palate speakers. Thirteen control groups and three cleft palate patients pre- and post operation were selected for these studies. The test words are composed by polysyllabic words: consonants between high vowel /i/ analysis. The cleft palate patients repeated test words pre- and post-operation from one, three and six month periods. The subjects repeated test words on Macquirer and on Nasometer Model 6200-3. The aerodynamic and acoustic results of nasalization show as follows: (1) The nasal rate in overall airflow of aspirated consonant for cleft palate patients shows higher levels than that of the control group. It had decreased since one month after operation. (2) The overall airflow of cleft palate patients is higher than in the control group, however oral air pressure is lower than control group. (3) The nasal airflow and the nasal rate in overall airflow of cleft palate patients has higher than the control group, however its decreased after operation. (4) The nasalance scores of cleft palate patients were 40% higher than that of the control group. The scores did not decrease after operation. The nasalance score of lateral and fricative sounds did not decrease after operation.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.5
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• pp.207-215
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• 2000

This study theoretically investigated the roll-off cleanliness operation to eliminate the built-in contaminants which are primarily the result of manufacturing and assembly procedures first. A rigorous analytical examination of the cleaning process associated with hydraulic systems was performed by developing the general filtration process equations. The sloughing process by which built-in contaminant is entrained in the system fluid was examined during the development of a general analytical expression for sloughing rate. This sloughing rate expression in conjunction with the filtration process equations have lead to a relationship rate expression in conjunction with the filtration process equations have lead to a relationship which describes the flushing and clean-up operation for the hydraulic systems. The effects of the primary roll-off cleanliness factors was discussed and illustrated on the figures. Then, the analytical results was shown to be usefully applied into the design of roll-off flushing equipment for the hydraulic system of a tractor.