• International Journal of Fluid Machinery and Systems
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• v.3 no.4
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• pp.369-378
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• 2010

The creation of the hydraulic turbine flow factor map will undoubtedly benefit its design by decreasing both the design cycle time and product cost. In this paper, the geometry and flow variables, which effectively affect the flow factor, are proposed, analyzed and determined. These flow variables are further used to create the operating condition maps by using different model approaches categorized into Response Surface Method (RSM) and Artificial Neural Network (ANN). The accuracies of models created by different approaches are compared and the performances of model approaches are analyzed. The influences of chosen variables and the combination of Principle Component Analysis (PCA) and model approaches are also studied. The comparison results between predicted and actual flow factors suggest that two-hidden-layer Feed-forward Neural Network (FFNN), and one.hidden-layer FFNN with PCA has the best performance on forming this mapping, and are accurate sufficiently for hydraulic turbine design.

• KIEE International Transactions on Power Engineering
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• v.5A no.3
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• pp.221-227
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• 2005

This paper evaluates minimum and maximum power exchange considering economic and technical characteristics between Russia and ROK. First, we evaluate minimum power exchange to assure the economic feasibility by comparison with the total cost and benefit of the interconnected line. For evaluating maximum exchange power, system constraints are considered, which are examined through load flow and dynamic analysis by using the PSS/E program. As a result of these evaluations, we suggest the reasonable range of power exchange between ROK and Russia considering economic and technical constraints with the interconnection scenario that power system interconnection between ROK and Russia will be realized in the year 2010.

• The Korean Journal of Pain
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• v.30 no.4
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• pp.265-271
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• 2017

Background: Health care services effort to provide alternative cardiac rehabilitation (CR) models to serve patients according to their preferences and needs. So, the present study aimed to assess and compare the effects of hospital-based and hybrid CR programs on chest pain intensity and discomfort in cardiac surgery patients. Methods: In this prospective study, 110 cardiac surgery patients were invited to the CR department of a hospital in the western part of Iran between March and July 2016. Patients were divided into two groups: hospital-based and hybrid CR. The hospital-based program included 26 sessions, and the hybrid program included 10 training sessions and exercise. The Brief Pain Inventory and Pain Discomfort Scale were used as research instrument, and data were analyzed using the paired t-test and ANCOVA. Results: The results indicated that both hospital-based and hybrid CR are effective in reducing the chest pain intensity and discomfort of cardiac surgery patients (P < 0.05). In addition, the comparison of scores before and after treatment using ANCOVA shows that no significant differences were observed between the two programs (P > 0.05). Conclusions: Traditional hospital-based CR delivery is still the first choice for treatment in developing countries. However, hybrid CR is as effective as a hospital-based program in reducing pain components and it includes only 38% of the total cost in comparison to hospital-based delivery. So, we recommend using hybrid CR according with the recommendations of American Heart Association about using CR for the management of angina symptoms.

• Resources Recycling
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• v.17 no.2
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• pp.55-62
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• 2008

Amount of waste is always generated in industrialization process and it is gradually increasing. Domestic and industrial waste in 2003 increased by 9.5 percent than that of the last year(2002), whereas the amount of construction waste increased largely by 21 percent. Recently construction waste of total waste accounts for nearly 50 percent, waste concrete and Ascon from the construction waste takes up to 73 percent. Furthermore, amount of natural materials are gradually decreasing, that is, they are not sufficient any more. Owing to these reasons, the importance of recycling construction waste has been emphasized. The use of recycling aggregate makes the disposal of construction waste easier as well as protects environment from gathering raw aggregate. Also, it has the alternative effect economizing the insufficient new natural aggregate. This study employs the cost-benefit model to analyze the economic effect of construction waste recycling of Ascon which takes relatively high part of the total waste. The cost-comparison between raw aggregate and recycling aggregate were analyzed. With the model, the economic effect of Ascon recycling in 2003 and 2004 in capital area of Korea were analysed. Cost comparison between raw aggregate and recycling aggregate were also carried out. The result showed that the economic effect of Ascon recycling increased to 0.0808 for 2004 as compared 0.0694 for 2003. We could not conclude using above data, but this result shows that the economic benefit of Ascon recycling of construction waste has increased.

• International Journal of Highway Engineering
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• v.18 no.4
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• pp.19-28
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• 2016

PURPOSES : Long-life asphalt pavements are used widely in developed countries. In order to be able to devise an effective maintenance strategy for such pavements, in this study, we evaluated the performance of the long-life asphalt pavements constructed along the national highways in South Korea. Further, an economic evaluation of the long-life asphalt pavements was performed based on a life-cycle cost analysis. We aimed to devise a model for evaluating the performance of long-life asphalt pavements using the national highway pavement management system (PMS) database as well as for analyzing the economic feasibility of such pavements, in order to promote their use in South Korea. METHODS : The maintenance history and pavement performance data were obtained from the national highway PMS database. The pavement performances for a total of 292 sections of 10 lanes (5 northbound lanes and 5 eastbound lanes) of national highways were used in this study. Models to predict the performances of hot mix asphalt (HMA) and long-life asphalt pavements under two distinct traffic conditions were developed using a simple regression method. Further, the economic feasibility of long-life asphalt pavements was evaluated using the Korea Pavement Management System (KoPMS). RESULTS : We developed service-life prediction models based on the traffic volume and the equivalent of single-axle load and found that long-life asphalt pavements have service lives 50% longer than those of HMA pavements. Further, the results of the economic analysis showed that long-life asphalt pavements are superior in terms of various economic indexes, including user cost, delay cost, total cost, and user benefits, even though their maintenance cost is higher than that of HMA pavements. A comparison of the economic feasibilities of the various groups showed that group A is superior to HMA pavements in all aspects except in terms of the maintenance criterion (crack 20% or higher) as per the NPV index. However, the long-life asphalt pavements in group B were superior in terms of the maintenance criterion (crack 25% or higher) regardless of the economic feasibility. CONCLUSIONS : The service life of long-life asphalt pavements was found to be approximately 50% longer than that of HMA pavements, regardless of the traffic volume characteristics. The economic feasibility of long-life asphalt pavements was evaluated based on the KoPMS. The results of the economic analysis were the following: long-life asphalt pavements are exceptional in terms of almost all factors, such as user cost, delay cost, total cost, and user benefit; however, the exception is the maintenance cost. Further, the economic feasibility of the long-life asphalt pavements in group B was found to be better than that of the HMA pavements (crack 25% or higher).

• Korean Chemical Engineering Research
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• v.52 no.5
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• pp.564-573
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• 2014

Economic optimization of cumene manufacturing process to produce cumene from benzene and propylene was studied. The chosen objective function was the operational profit per year that subtracted capital cost, utility cost, and reactants cost from product revenue and other benefit. The number of design variables of the optimization are 6. Matlab connected to and controlled Unisim Design to calculate operational profit with the given design variables. As the first step of the optimization, design variable points was sampled and operational profit was calculated by using Unisim Design. By using the sampled data, the estimation model to calculate the operational profit was constructed, and the optimization was performed on the estimation model. This study compared second order polynomial and support vector regression as the estimation method. As the sampling method, central composite design was compared with Hammersley sequence sampling. The optimization results showed that support vector regression and Hammersley sequence sampling were superior than second order polynomial and central composite design, respectively. The optimized operational profit was 17.96 MM$ per year, which was 12% higher than 16.04 MM$ of base case.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.2
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• pp.799-805
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• 2016

Background: There is no standard treatment for patients with platinum-resistant or refractory epithelial ovarian cancer. Single agent chemotherapies have evidence of more efficacy and less toxicity than combination therapy. Most are very expensive, with appreciable toxicity and minimal survival. Since it is difficult to make comparison between outcomes, economic analysis of single-agent chemotherapy regimens and best supportive care may help to make decisions about an appropriate management for the affected patients. Objective: To evaluate the cost effectiveness of second-line chemotherapy compared with best supportive care for patients with platinum-resistant or refractory epithelial ovarian cancer. Materials and Methods: A Markov model was used to estimate the effectiveness and total costs associated with treatments. The hypothetical patient population comprised women aged 55 with platinum-resistant or refractory epithelial ovarian cancer. Four types of alternative treatment options were evaluated: 1) gemcitabine followed by BSC; 2) pegylated liposomal doxorubicin (PLD) followed by BSC; 3) gemcitabine followed by topotecan; and 4) PLD followed by topotecan. Baseline comparator of alternative treatments was BSC. Time horizon of the analysis was 2 years. Health care provider perspective and 3% discount rate were used to determine the costs of medical treatment in this study. Quality-adjusted life-years (QALY) were used to measure the treatment effectiveness. Treatment effectiveness data were derived from the literature. Costs were calculated from unit cost treatment of epithelial ovarian cancer patients at various stages of disease in King Chulalongkorn Memorial Hospital (KCMH) in the year 2011. Parameter uncertainty was tested in probabilistic sensitivity analysis by using Monte Carlo simulation. One-way sensitivity analysis was used to explore each variable's impact on the uncertainty of the results. Results: Approximated life expectancy of best supportive care was 0.182 years and its total cost was 26,862 Baht. All four alternative treatments increased life expectancy. Life expectancy of gemcitabine followed by BSC, PLD followed by BSC, gemcitabine followed by topotecan and PLD followed by topotecan was 0.510, 0.513, 0.566, and 0.570 years, respectively. The total cost of gemcitabine followed by BSC, PLD followed by BSC, gemcitabine followed by topotecan and PLD followed by topotecan was 113,000, 124,302, 139,788 and 151,135 Baht, respectively. PLD followed by topotecan had the highest expected quality-adjusted life-years but was the most expensive of all the above strategies. The incremental cost-effectiveness ratios (ICER) of gemcitabine followed by BSC, PLD followed by BSC, gemcitabine followed by topotecan and PLD followed by topotecan was 344,643, 385,322, 385,856, and 420,299 Baht, respectively. Conclusions: All of the second-line chemotherapy strategies showed certain benefits due to an increased life-year gained compared with best supportive care. Moreover, gemcitabine as second-line chemotherapy followed by best supportive care in progressive disease case was likely to be more effective strategy with less cost from health care provider perspective. Gemcitabine was the most cost-effective treatment among all four alternative treatments. ICER is only an economic factor. Treatment decisions should be based on the patient benefit.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.4
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• pp.391-397
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• 2011

Conventional film radiographic test has been generally and widely used in the inspection on the weldment for quality assurance. On the other hand, since the analog RT is well known for typical time and cost consuming method with complex process of inspection, the industry has researched various ways how to improve radiographic test technology. In this study, we verified the fact that digital RT provides a lot more benefit in effectively detecting defects, ever film details, through digital processing of image enhancement, compared to film RT. As a result, we reached conclusion that digital RT is positively able to replace the film RT in industry in part or in whole.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.305-308
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• 2002

More complex radiotherapy techniques using multi leaf collimation(MLC) such as intensity-modulated radiation therapy(IMRT) has been increasing the significance of verification of leaf position and motion. Due to the reliability and robustness, quality assurance(QA) of MLC is usually performed with portal films. However, the advantage of ease of use and capability of providing digital data of electronic portal imaging devices(EPIDs) have attracted many attentions as alternatives of films for routine quality assurance in spite of the concerns about their clinical feasibility, efficacy, and the cost to benefit ratio. In our work, the method of routine QA of MLC using electronic portal imaging(EPI) was developed. The verification of availability of EPI images for routine QA was performed by comparison with those of the portal films which were simultaneously obtained when radiation was delivered and known prescription input to MLC controller. Specially designed test patterns of dynamic MLC were applied to image acquisition. Quantitative off-line analysis using edge detection algorithm enhanced the verification procedure in addition to on-line qualitative visual assessment. In conclusion, the EPI is available enough for routine QA with the accuracy of portal films.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.1
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• pp.111-124
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• 2014

Decentralized water supply systems, treating the water in users'vicinity, cutting down the distribution system, utilizing the alternative water resources(rainwater harvesting, water reclamation and reuse and so on.) and saving energy and other resources, could be categorized into POU(Point-Of-Use), POE(Point-Of-Entry) and community small scale system. From the literature review, we could thought that decentralized water supply system and hybrid system(integrating centralized and decentralized water supply system within urban water management) might have strengthening comparative advantages to centralized system with respect to: (1) water security, (2) sustainability, (3) economical affordability. Even though it is difficult to derive and quantify direct benefit advantages from decentralized and hybrid system in comparison with centralized system, (1) operational cost reduction, (2) assurance for safe and stability water supply and (3) greenhouse gas reduction can be expected from successful establishment of the former.