• International journal of advanced smart convergence
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• v.8 no.4
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• pp.26-33
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• 2019

We conducted research to evaluate economically and engineering about the synthesis of Magnesium Oxide, MgO, nanoparticles using physicochemical methods. The method used was economic evaluation by calculating GPM, BEP, PBP, and CNPV. The other method used was engineering perspective. MgO nanoparticles were synthesized by reacting Mg(NO₃)₂ and NaOH with a mole ratio 1: 2. Mg(OH)₂ formed was heated and calcined to remove water content and to oxidation to form MgO. An economic evaluation by calculating GPM and CNPV for the production of MgO nanoparticles on an industrial scale shows that the payback period (PBP) occur in the third year and profits increase each year. Tax variations show that the higher of tax, the lower profits received. When there was an increase of selling prices, the profit was greater. The variable cost used is the price of raw material. When there was an increased in the variable cost price, the payback period was longer and the profits was reduced. The benefit of this research is knowing the industrial production of MgO nanoparticles is beneficial. The function of MgO nanoparticles is a material for the manufacture of ceramics and can be used as an antimicrobial in the water filtration process.

• Steel and Composite Structures
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• v.29 no.3
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• pp.363-377
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• 2018

An efficient and free of shear locking finite element model is developed and employed to study free vibration of tapered bidirectional functionally graded material (BFGM) beams. The beam material is assumed to be formed from four distinct constituent materials whose volume fraction continuously varies along the longitudinal and thickness directions by power-law functions. The finite element formulation based on the first-order shear deformation theory is derived by using hierarchical functions to interpolate the displacement field. In order to improve efficiency and accuracy of the formulation, the shear strain is constrained to constant and the exact variation of the cross-sectional profile is employed to compute the element stiffness and mass matrices. A comprehensive parametric study is carried out to highlight the influence of the material distribution, the taper and aspect ratios as well as the boundary conditions on the vibration characteristics. Numerical investigation reveals that the proposed model is efficient, and it is capable to evaluate the natural frequencies of BFGM beams by using a small number of the elements. It is also shown that the effect of the taper ratio on the fundamental frequency of the BFGM beams is significantly influenced by the boundary conditions. The present results are of benefit to optimum design of tapered FGM beam structures.

• Korean Journal of Agricultural Science
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• v.30 no.1
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• pp.89-101
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• 2003

For the pre-feasibility study and project evaluation, the discount rate or cutoff rate should be given by the government authority. To get the Benefit/Cost Ratio, NPV(Net Present Value) and IRR(Internal Rate of Return) of the public investment projects, the pertinent and realistic discount rate should be determined to be suitable to the present time period. The cut-off rates in Korea were equivalent to 15% in 1970's, 10% in 1980's and 8% in 1990's. The prevailing rate of discount as 8% is considered not to be suitable for the 2000's public project appraisal considering the present interest rates on deposit and national bonds. To determine the socio-economic feasibility of the public projects, the IRR should be bigger than the present cutoff rate. When we still use the high old rate of discount, the analytical results of project appraisal will show always economically unfeasible. Therefore the new rate of discount suitable for present time should be determined by the government. The public projects to be implemented in 2000 year onward are recommended to be adapted 5% of cutoff rate for the project appraisal and evaluation according to the results of reviewing the tendency of discount rates and market rates of interest in Korea.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2000.11a
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• pp.221-227
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• 2000

The optimal capacity of CGS(Co-Generation Sys.) for APT. complex is 300kW output of electricity power from being considered the simple payback period, loss and benefit, and the running mode of CGS. The proper operation mode of CGS is as follows; If the demanding electricity load of APT. complex is within the range of capacity of generator(300kW), CGS is connected and operated with KEPCO grid. When the load ratio is over 50% of normal load of CGS(300kW), only CGS supply electricity demand. If not, the electricity line of CGS is exchanged to that of KEPCO.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.2
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• pp.579-603
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• 2018

In this paper we propose a QoS-enhanced intelligent stochastic optimal fair real-time packet scheduler, QUEST, for 4G LTE traffic in routers. The objective of this research is to maximize the system QoS subject to the constraint that the processor utilization is kept nearly at 100 percent. The QUEST has following unique advantages. First, it solves the challenging problem of starvation for low priority process - buffered streaming video and TCP based; second, it solves the major bottleneck of the scheduler Earliest Deadline First's failure at heavy loads. Finally, QUEST offers the benefit of arbitrarily pre-programming the process utilization ratio.Three classes of multimedia 4G LTE QCI traffic, conversational voice, live streaming video, buffered streaming video and TCP based applications have been considered. We analyse two most important QoS metrics, packet loss rate (PLR) and mean waiting time. All claims are supported by discrete event and Monte Carlo simulations. The simulation results show that the QUEST scheduler outperforms current state-of-the-art benchmark schedulers. The proposed scheduler offers 37 percent improvement in PLR and 23 percent improvement in mean waiting time over the best competing current scheduler Accuracy-aware EDF.

• International Journal of Industrial Entomology and Biomaterials
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• v.2 no.1
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• pp.75-78
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• 2001

The whitefly, Dialeuropora decempuncta Quaintance and Baker (Homoptera : Aleyrodidae) causing considerable damage to mulberry, Morus alba. Crop loss caused by the whitefly was estimated in mulberry. Quantitative yield loss was estimated on the basis of harvest data from both sprayed and unsprayed plots. Data on pest incidence has been recorded at weekly intervals in both sprayed and unsprayed plots from 30 th day of plant age till harvesting i.e., 60 days after pruning in August October season. An attempt has been made to establish a relationship between whitefly population and percentage of crop loss due to it. Percentage of crop loss due to whitefly has got a linear relationship with the whitefly population. An initial population of 24 adults/top leaf would be able to cause 24% loss (l,630 Kg leaf/ha ) in a period of 30 days. Economic analysis postulates that application of pesticide can stove a net amount of 1,630 Kg leaf/ha which is sufficient to produce 67.65 Kg of additional multivoltine cocoons. This determines the cost/benefit ratio which will enable to workout the economics of management practices.

• Korean Journal of Veterinary Research
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• v.50 no.4
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• pp.279-284
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• 2010

Combination therapy of antibiotics is leading to improved efficacy or safety profiles with decrease emergence of bacterial resistance. Because of this benefit, many of antibacterial combinations have been used in veterinary practice for the past few decades. The purpose of this study was to examine the in vitro activity of an amoxicillin alone and in combination with other antibiotics against pathogenic bacteria of fish origin. Based on the fractional inhibitory concentration (FIC) index (FIC $$\leq_-$$ 0.5), a synergistic interaction was shown in combination of florfenicol with amoxicillin or cefuroxime. The combination of florfenicol and amoxillin showed higher antibacterial activity than that of florfenicol and cefuroxime. Ratio of amoxicillin and florfenicol in combination was 1 : 1, which showed the antibacterial activity against bacterial isolates of fish as compared with other ratios. A synergetic effect of the combination (amoxicillin and florfenicol) was further confirmed in the time-kill curve study. The study showed a better in vitro antibacterial activity of a 1 : 1 combination of amoxicillin and florfenicol than the individual antibacterial against bacterial isolates of fish. In conclusion, the combination of florfenicol and amoxicillin may serve as a potential antibacterial therapy in fishes infected pathogenic bacteria.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.9
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• pp.213-242
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• 1998

Even in the best of economic environments, restaurants menu pricing is a serious concern to those in the food service industry. During times of rapid inflation, closer government regulation of compensation practices, and limited gains in worker productivity, the decisions regarding the proper charge for menu items become increasingly important. In addition to many operational and managerial factors, an important ingredient in the food service enterprise's success is its ability to meet the market by providing the value expected. The contribution-margin approach to pricing described above is familiar to cost accountants, who will also recognize that it admits of much elaboration before it can become a tool for day-to-day decisions. But the system probably has the greatest promise for multi-unit companies, where the cost benefit ratio of additional refinements improves in proportion to the number of operations. For example, the analysis required to specify the demand function better becomes less expensive if the findings can be applied to the pricing structure of numerous units. In any of its many adaptations, the essence of the integrated menu pricing system remains its ability to bring together the relevant revenues and costs with the operator's sense of the market and competitive environment to suggest prices that maximize profits.

• Management Science and Financial Engineering
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• v.10 no.1
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• pp.25-41
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• 2004

There have been many studies to build a model that can help investors construct optimal portfolio. Most of the previous models, however, are based upon the path-breaking Markowitz model (1959) which is a quantitative model. One of the most important problems with that kind of quantitative model is that, in reality, most of the investors use not only quantitative, but also qualitative information when they select their optimal portfolio. Since collecting both types of information from the markets are time consuming and expensive, making a set of target assets smaller, without suffering heavy loss in the rate of return, would attract investors. To extract only desired assets among all available assets, we need knowledge that identifies investors' preference for the risk of the assets. This study suggests two-layer decision-making rules capable of identifying an investor's risk preference and an architecture applying them to a quantitative portfolio model based on risk and expected return. Our knowledge-based portfolio system is to build an investor's preference-oriented portfolio. The empirical tests using the data from Korean capital markets show the results that our model contributes significantly to the construction of a better portfolio in the perspective of an investor's benefit/cost ratio than that produced by the existing portfolio models.

• Journal of Korean Institute of Industrial Engineers
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• v.19 no.2
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• pp.23-34
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• 1993

Although there are numerous studies that address the problem of optimal machine grouping and part family classification for cellular manufacturing, little research has been reported that studies the conditions where cellular manufacturing is appropriate. This paper, in order to evaluate and compare the job shop with the GT cellular shop, the performance of those shops were simulated by using SIMAN. We tested the effect of independent variables including changes of product demands, intercell flow level, group setup time, processing time variability, variety of material handling systems, and job properties (ratio of processing time and material handling time). And also performance measures (dependent variables), such as machine utilization, mean flow time, average waiting time, and throughput rate, are discussed. Job shop model and GT cellular shop written in SIMAN simulation language were used in this study. These systems have sixteen machines which are aggregated as five machine stations using the macro feature of SIMAN. The results of this research help to better understand the effect of production factors on the performance of cellular manufacturing systems and to identify some of the necessary conditions required to make these systems perform better than traditional job shops. Therefore, this research represents one more step towards the characterization of shops which may benefit from cellular manufacturing.