• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.1
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• pp.50-56
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• 2017

The IRR (internal rate of return) is often used by investors for the evaluation of engineering projects. Unfortunately, it is widely known that it has serial flaws. Also, External rate of returns (ERRs) such as ARR (Average Rate of Return) or MIRR (MIRR, Modified Internal Rate of Return) do not differentiate between the real investment and the expenditure. The PRR (Productive rate of return) is faithful to the conception of the return on investment. The PRR uses the effective investment instead of the initial investment. In this paper, we examined two cases of the engineering project. the one is a traditional engineering project with financing activity, another is the project with R&D. Although the IRR has only one value, it overestimates or underestimate profitabilities of Engineering Projects. The ARR and the MARR assume that a returned cash reinvest other projects or assets instead of the project currently executing. Thus they are only one value of a project's profitability, unlike the IRR. But the ARR does not classify into the effective investment and non-investment expenditure. It only accepts an initial expenditure as for an investment. The MIRR also fails to classify into the investment and the expenditure. It has an error of making a loss down as the investment. The IRR works as efficiently as a NPW (Net Present Worth). It clearly expresses a rate of return in respect of an investment in an engineering project with a loan. And it shows its ability in an engineering project with a R&D investment.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.1
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• pp.41-49
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• 2010

Return flow rate of irrigation water was estimated by water balance method. Daepyeong pumping district to irrigate 75.8 ha of rice paddy in the Geum river basin was selected to install gauging instruments to collect data such as weather, water levels, infiltration rate and evapotranspiration during irrigation season (May 27 to Sept. 20) in 2003 and 2004. Irrigation and drainage discharge were calculated from the rating curve and evapotranspiration was estimated both by the modified Penman formula and by the lysimeter. The results were as followed : 1. Total amounts of pumping water during irrigation season were $1,076,000\;m^3$ in 2003 and $1,848,000\;m^3$ in 2004. Total amounts of rainfall were 1336.0mm and 1003.0mm respectively during the irrigation season in 2003 and 2004. 2. It was surveyed that the amount of infiltration was 196.5 mm (2.2 mm/day). The gauged evapotranspiration was 311.0 mm (3.5 mm/day) and the calculated evapotranspiration was 346.0 mm (3.9 mm/day) during irrigation period in 2003. It was surveyed that the amount of infiltration was 169.9 mm (2.4 mm/day). The amount of gauged evapotranspiration was 377.3 mm (5.3 mm/day) and the calculated evapotranspiration was 454.5 mm (6.6 mm/day) during irrigation period in 2004. 3. The rates of quick and delayed return flow were 52.4 % and 17.7 % respectively, and so return flow rate was 70.1 % in 2003. The rates of quick and delayed return flow were 45.4 % and 16.1 % respectively, and so return flow rate was 61.5 % in 2004. It means that average return flow rate in the Daepyeong pumping district was assumed to be 65 %.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.3
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• pp.95-99
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• 2015

The IRR(internal rate of return) is often used by investors for the evaluation of engineering projects. Unfortunately, it has serial flaws: (1) multiple real-valued IRRs may arise; (2) complex-valued IRRs may arise; (3) the IRR is, in special cases, incompatible with the net present value (NPV) in accept/reject decisions. The efforts of management scientists and economists in providing a reliable project rate of return have generated over the decades an immense amount of contributions aiming to solve these shortcomings. Especially, multiple internal rate of returns (IRRs) have a fatal flaw when we decide to accep it or not. To solve it, some researchers came up with external rate of returns (ERRs) such as ARR (Average Rate of Return) or MIRR (MIRR, Modified Internal Rate of Return). ARR or MIRR. will also always yield the same decision for a engineering project consistent with the NPV criterion. The ERRs are to modify the procedure for computing the rate of return by making explicit and consistent assumptions about the interest rate at which intermediate receipts from projects may be invested. This reinvestment could be either in other projects or in the outside market. However, when we use traditional ERRs, a volume of capital investment is still unclear. Alternatively, the productive rate of return (PRR) can settle these problems. Generally, a rate of return is a profit on an investment over a period of time, expressed as a proportion of the original investment. The time period is typically the life of a project. The PRR is based on the full life of the engineering project. but has been annualised to project one year. And the PRR uses the effective investment instead of the original investment. This method requires that the cash flow of an engineering project must be separated into 'investment' and 'loss' to calculate the PRR value. In this paper, we proposed a tabulated form for easy calculation of the PRR by modifing the profit and loss statement, and the cash flow statement.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.2
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• pp.85-96
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• 2021

Irrigation return flow is defined as the excess of irrigation water that is not evapotranspirated by direct surface drainage, and which returns to an aquifer. It is important to quantitatively estimate the irrigation return flow of the water cycle in an agricultural watershed. However, the previous studies on irrigation return flow rates are limitations in quantifying the return flow rate by region. Therefore, simulating irrigation return flow by accounting for various water loss rates derived from agricultural practices is necessary while the hydrologic and hydraulic modeling of cultivated canal-irrigated watersheds. In this study, the irrigation return flow rate of agricultural water, especially for the entire agricultural watershed, was estimated using the SWMM (Storm Water Management Model) module from 2010 to 2019 for the Madun reservoir located in Anseong, Gyeonggi-do. The results of SWMM simulation and water balance analysis estimated irrigation return flow rate. The estimated average annual irrigation return flow ratio during the period from 2010 to 2019 was approximately 55.3% of the annual irrigation amounts of which 35.9% was rapid return flow and 19.4% was delayed return flow. Based on these results, the hydrologic and hydraulic modeling approach can provide a valuable approach for estimating the irrigation return flow under different hydrological and water management conditions.

• Korean Journal of Social Welfare
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• v.41
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• pp.43-67
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• 2000

The main source in financing the National Pension benefits is the contribution raised from the insured's earnings. So, Most of the insured take a great interest in the questions of what return on the payment of contribution National Pension benefits provide and whether there be the difference in return according to earnings level. The Purpose of this study is to assess money's worth of National Pension and to answer the above questions. There are two basic types of money worth analysis, empirical and hopothetical. This study basically belongs to the former in terms that it is based on actual earnings and insured term. For performing money's worth analysis, four different measures which are referred as the "break-even period", the "benefit/tax ratio", the "net lifetime transfer", the "internal rate of return" are used and they all involve the way in which the relationship between the present value of contributions and the present values of benefit is present. The results which evaluate average money's worth of accrued rights before 1999 are le as follows. Break-even period is about 43 months, benefit/tax ratio being 4.9, net lifetime transfers being about 37 mil1ion won, internal rate of return being 33.2%. This verifies that money' worth of National Pension is much higher than actuarially fair. In the mean while, money' worth is proved to be very different according to earnings level. The progressivity relationship between earnings level and rate of return is found in all measures but net lifetime transfer.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.905-912
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• 2006

In this paper, simulation methods of the system dynamics model developed by Das et al. (1997) for activated-sludge wastewater treatment plants are illustrated in an attempt to determine the operating rules and the policies related to capacity expansion of an activated-sludge wastewater treatment plant. For existing conditions, the analyses were performed by varying activated-sludge return rate to observe changes in effluent water quality and treatment efficiency. The effluent water quality is also analyzed for various average daily inflow conditions and activated-sludge return rates. As a result, without expanding the aeration tank, maximum average daily inflow that can satisfy the effluent water quality standard of BOD $0.02kg/m^3$ was determined as $2,840m^3/hr$, subject to 100% of activated-sludge return rate while other factors remain constant. When the activated-sludge return rate is less than 100%, expansion of the aeration tank is necessary and minimum sizes of the aeration tank to satisfy the effluent water quality standard were determined for various activated-sludge return rates. In addition, the total operating and maintenance as well as unit treatment cost regression equations for activated-sludge wastewater treatment plants are suggested by using the cost data that are obtained from Water and Wastewater Division, Ministry of Environment. The regression analyses showed that the economies of scale phenomena exist in the operating and maintenance costs of activated-sludge wastewater treatment plants.

• Journal of IKEEE
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• v.23 no.4
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• pp.1195-1202
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• 2019

The safe return home system automatically tracks and makes a video-recording the client by selecting and controlling CCTV cameras near the client using GPS location information received from the smart device possessed by the service client. This service helps clients to return home safely when there is a crime-ridden district on their late night return home route. If the CCTV cameras that can capture the client are already occupied and used by other clients, concession of occupied CCTV cameras is required to capture the new client. To tackle the limitation, we developed an extended method that considered both the average distances between the client and CCTV cameras and the service rates. As a result, the average distance between CCTV cameras and clients is kept close, and service rates are improved.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.1
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• pp.137-142
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• 2019

There are two methods for evaluating two or more mutually exclusive projects. One is a total investment approach and the other is an incremental investment approach. The former can rank projects by the criterion of the net present value, but the latter can't do it. An incremental investment approach is only possible when all pairwise alternatives are compared. Thus an incremental investment approach is superior in ranking them over an incremental investment approach. To do so, a principle of comparison must be established. Comparisons of profitability are reasonable when operating the same amount of investment over the same period of time. One principle is that all projects are invested in the largest of the projects. Another principle is that all projects are invested during the longest project life of the projects. In this paper, even if the principle is followed, it will be shown that the external rate of return fails to rank them. However, the productive rate of return criterion would prove to be able to rank them like the net present value standard, provided that the principle of comparison is kept. In addition, rate of returns can be assessed so that all mutually exclusive projects can be compared at once, such as on the criterion of the net present value. That is, it can be also compared with many other returns, such as the profit rates on financial investments or real investments.

• KDI Journal of Economic Policy
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• v.27 no.1
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• pp.81-122
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• 2005

The paper aims to establish the characteristics of the Korean firms' R&D investment and to estimate the private rate of return to R&D investment. For the empirical analysis, a balanced panel data is constructed with 695 firms on 8 year observations. The panel data enables to characterize R&D investment of the Korean firms, which is mostly conformed to the 'stylized facts' of R&D investment that found in the previous studies on foreign firms. Klette model was used to estimate the private rate of return on R&D investment and depreciation rate of R&D capital. The paper estimates that the rate of return on R&D investment is 10.5% on average or 16.4% on median for the whole industry whereas manufacturing firms show 10.4% on average or 16.4% on median. The depreciation rate was estimated about 32.9% for whole industry, where it ranges from the minimum 11.6% for metal industry and 49.5% for services. The median estimate of the rate of return for R&D investment of Korean firms is roughly two times higher than real interest rates for the same period, which implies that R&D investment allows sizable rent in addition to the opportunity cost of capital investment.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.10a
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• pp.77-80
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• 2000

Feedback herding strategy in stock market means considering other investor's strategy as a basis of market forecasting of next term. Generally, individual investors use that strategy which mimics the strategy of institutional investors. When it is used in stock market, both kind of investors, preceders and followers, can take the higher average of rate of return to normal market in which no feedback herding strategy is not use, the more investors take part in. And variance of return, the risk of investment, are same to both group.