• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.61-67
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• 2005

Agricultural water for rice growing is the important factor of water resources in Korea. so, it is imperative to know the practice of water management in paddy field. The experimental site has been operated in order to investigate water management practice and water supply discharge since 2001. There are 8 irrigation areas which are observed the water supply discharge in this site. We have investigate the water management practice in this site and we know that the practical date of rice growing stages and the date for calculating the water demand in paddy field. So, There is much differences between the calculated water demand and practical water supply. We could reduce the differences by calculating the water demand using the practical date of rice growing stages.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.1
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• pp.16-21
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• 2018

As a result of the Fukushima disaster and climate change due to excessive greenhouse gases, international energy affairs are currently focused on establishing safe and environment-friendly policies. To achieve this, Republic of Korea has established a plan for environment-friendly energy supplies. It is expected that policy enforcement will be accompanied by an increase in energy supply costs. An analysis of energy supply costs is necessary before the establishment of any national energy policy. This paper analyzes and compares the energy supply costs accompanying environmental and nuclear energy policies, based on the Korean National Energy Master Plan and the Basic Plan for Long-Term Electricity Supply and Demand, in order to understand the implications of these national energy policies.

• Korean System Dynamics Review
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• v.12 no.4
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• pp.157-175
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• 2011

The purpose of this paper is to find out the effects of the gambler's fallacy bias on the supply chain. For this study, the simulation was based on a casual structure of the Beer Distribution Game from Sterman(2000)'s Business Dynamics and designed into 2 different models : the first model carries the exact same structure as the reference mentioned above and for the second model, the comparison model is used reflecting gambler's fallacy bias. Each model has 2 different demand patterns. The 4 cases of models was tested with 1,000 different random number seeds. The results for the simulation are following : In the aspect of the inventory and out of stock, the basic model resulted better than the comparison. However, in the bullwhip effect, the comparison model has less than the basic in terms of the level demand pattern. But there was no significant difference in the cycle demand.

• Journal of Korean Society of Forest Science
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• v.83 no.2
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• pp.133-147
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• 1994

Wastepaper recycling has significant implications not only in providing scarce raw material input for the paper industry but in environmental concerns such as reducing solid waste disposal, energy conservation and preservation of forest resources. The objectives of this study was (1) to develop an econometric model of demand for and supply of wastepaper, (2) to forecast wastepaper consumption and price to the year 2000 applying the econometric models estimated and (3) to estimate the elasticity of variables which are included in the wastepaper supply and demand equations. In this study wastepaper was classified into three groups, old newsprint, old corrugated and mixed For each group such as demand and supply equation were estimated. The demand equations were estimated as a function of paper and paper product consumption and wholesale price index and supply equations as a function of wastepaper price, one year lagged paper and paperproduct consumption and transportation price. Applying the econometric models to forcasting results in the future consumption and supply of wastepaper projected as 11.645 million MT and 7.396 million MT in 2000, respectively. The rate of wastepaper self-supply is forcasted about 63.5% in 2000. Especially, the rate of old neswprint self-supply is predicted about 16% which means about 2.2 million MT of old newsprint should be imported from foreign countries. Lastly, some policy measures to promote wastepaper recycling rate based upon economic and physical characteristics of wastepaper and market structure are suggested.

• Korea journal of population studies
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• v.8 no.1
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• pp.47-65
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• 1985

Three stages of population growth during last forty years affected differently to the labor force and employment in Korea. The first impact of rapid population growth on the labor force occured after the end of World War II. Sudden growth of population due to repartriation and refugees directly increased the labor force. Deteriorating labor market conditions were caused not only by the explosive labor supply but also by the shortage of employment opportunities due to a lack of productive facilities. This severe excess supply of labor continued until the early 196Os. Population growth in the second stage which caused by high fertility during the post Korean War baby boom period induced an eventual increase in the labor supply with time lag of more than fifteen years. Younger persons born during baby boom period were flooded the labor market. Fortunately, job opportunities were expanded more rapidly than the labor force supply because high rates of economic growth and speedy industrialization were continued until the later half of 1970s. Unemployment, therefore, decreased dramatically during this period. The effect of third stage which is characterized as mitigated population growth due to birth control has appeared in the labor market since late 1970s. The growth rate of labor force has been going down and the proportion of younger workers was also been decreasing. From the early 1980s, furthermore, partial disharmony between supply of and demand for the younger workers is closing up. Less educated younger workers who works at low wage are lacking while more educated youngers who want to work at high wage are being excess, because a lot of younger prefer higher education rather than productive job. It is expected that the structural inharmony will be diversified in the future in Korea. The labor force will be changed to middleaged, highly educated and womenized till year 2000, and, after then, to old-aged. On the demand side, industries and jobs will transferred to be labor-saving and soft. These structural changes of labor supply and demand will not matching in time. Aggregate supply of labor force will be steadily increasing more rapidly than aggregate demand for labor until year 2000, and this trend will continue to the first one or two decades of the 2lth century because the persons born dufing the baby boom pariod are being eligible couples in recent. Therefore, conclusion is that appropriate manpower development policy as well as sustained birth control policy is necessary for harmonizing the structural unbalance and the disequilibrium between aggregate labor supply and demand in the future.

• Food Science of Animal Resources
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• v.42 no.5
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• pp.762-774
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• 2022

The COVID 19 pandemic resulted in a considerable influence on the world economy. Being a big sector of the economy, the food supply chain struggled. The meat supply chain was most notably affected as every part of the supply chain from farm to shelf was closely inter-related. With the closure of businesses and restaurants the demand for at home food from grocery stores increased. Meat production facilities were impacted when the virus spread to the workers causing facilities to close or line speeds to slow. The combination of these two issues, in turn, led to there being less meat on the shelves. With less meat animals being harvested, there was less demand for livestock leading to farmers having an excess in slaughter ready animals. The decreased demand for livestock led to economic issues as money was lost in multiple sections of the supply chain. Aside from the economy and supply chain issues, other issues include concerns over the safety of meat products due to decreased safety protocols to increase line speed. Additionally, concerns of animal welfare with the excess of animals being culled were raised due to decreased capacity in processing facilities. While this review paper mainly focuses on characterizing the impact of COVID 19 on the meat supply chain in the USA, the compiled information should be able to provide practical insights to the meat/food industry across the globe to develop potential mitigating strategies against the COVID 19 and/or any similar pandemic incidences in the future.

• Journal of the Korea Society for Simulation
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• v.15 no.3
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• pp.39-47
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• 2006

In most of supply chain planning practices, the estimated demands, which are forecasted for each individual period in a forecasting window, are regarded as deterministic. But, in reality, the forecasted demands for the periods of a given horizon are stochastically distributed. Instead of using a safety stock, this study considers a direct control of service level by choosing the demand used in planning from the distributed forecasted demand values for the corresponding period. Using the demand quantile and echelon stock concept, we propose a simple but efficient heuristic algorithm for multi-echelon serial systems under service level constraints. Through a comprehensive simulation study, the proposed algorithm was shown to be very accurate compared with the optimal solutions.

• Journal of the Korean Operations Research and Management Science Society
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• v.31 no.1
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• pp.73-82
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• 2006

Supply chain management (SCM) has been regarded as one of the most critical issues in the current business environment. Moreover, supply chain partnerships between suppliers and buyers in SCM have had a significant impact on supply chain performance. In this paper, we conduct a quantitative analysis for supplier-buyer's profit sharing and pricing policies based on supply chain partnerships. For this purpose, we assume that a two echelon supply chain with a single supplier and a single buyer is given and the buyer faces deterministic demand which is not only a function of buyer's selling price, but also strictly decreasing, concave, and twice differentiable function. Then we will prove the following. Firstly, without supply chain partnerships, there exist supplier and buyer's selling prices per unit such that their total profits are maximized, under the assumption that buyer's order quantity is exactly equal to the demand buyer faced. Secondly, buyer's selling price per unit which maximizes supply chain's total profit with supply chain partnerships is lower than buyer's selling price per unit which maximizes buyer's total profit without supply chain partnerships. Thirdly, given supplier's selling price per unit. buyer's total profit without supply chain part nerships is greater than that with supply chain partnerships, whereas the opposite case happens for supplier's total profit. Finally, there exists supplier's selling price per unit which makes the maximum total profits for both supplier and buyer with supply chain partnerships greater than those obtained for any given supplier's selling price per unit without supply chain partnerships.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.6
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• pp.151-156
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• 2020

Various institutions provide various welfare-related services, and accordingly, the quantity and quality of welfare-related services are improved. Along with the improvement of welfare services, the rate of fraudulent and redundant supply and demand due to inappropriate applicants is also increasing. In particular, in the case of similarly promoted projects by various institutions, confirmation of duplicate applications may be insufficient due to system inconsistency between institutions and delays in qualification verification, which may result in duplicate supply and demand. In this paper, in order to prevent the redundant supply and demand related to welfare service similar projects in various institutions, the problem of data management and sharing between institutions was reviewed and a method of applying blockchain technology was proposed step by step. Through the proposal of this paper, transparent data management of recipients is possible, and through this, trust-based welfare benefit management will be possible.

• Journal of Korean Society of Forest Science
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• v.98 no.3
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• pp.311-318
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• 2009

This study purposed to construct supply and demand potential map of forest bioenergy with a GIS-based decision support system. The target areas of this study were a part of the forests in Yongdong region, Gangwondo, and most types of forests were pinus densiflora, pinus koreaiansis, and Oak. Data about forest type, age classes, the number of households, regional silviculture planning was stored in GIS to define the potential areas for supplying potential bioenergy from the forests, and to assess biomass available for a household. Theoretical potential biomass energy based on silviculture plan was estimated in average 3,144 Tcal, and this quantity will be enough to supply the quantity of demand of households in that area. However, if it assumed that average collecting rates of Kangwon province were 10%, the available quantity of biomass will be between 6% and 15% of demand. If the collecting rates were 60%, the supply of biomass could exceed the quantity of demand in certain cities.