• Journal of Power Electronics
• /
• v.9 no.6
• /
• pp.919-928
• /
• 2009

Microgrids (MGs) are typically comprised of distributed generators (DGs) including renewable energy sources (RESs), storage devices and controllable loads, which can operate in either interconnected or isolated mode from the main distribution grid. This paper introduces a novel dynamic programming (DP) approach to MG optimization which takes into consideration the coordination of energy supply in terms of heat and electricity. The DP method has been applied successfully to several cases in power system operations. In this paper, a special emphasis is placed on the uncontrollability of RESs, the constraints of DGs, and the application of demand response (DR) programs such as directed load control (DLC), interruptible/curtaillable (I/C) service, and/or demand-side bidding (DSB) in the deregulated market. Finally, in order to illustrate the optimization results, this approach is applied to a couple of examples of MGs in a certain configuration. The results also show the maximum profit that can be achieved.

• IE interfaces
• /
• v.16 no.3
• /
• pp.280-290
• /
• 2003

Many firms are trying to optimize their production and distribution functions separately, but possible savings by this approach may be limited. Nowadays, it is more important to analyze these two functions simultaneously by trading off the costs associated with the whole. In this paper, I treat a production and distribution planning problem for single-period inventory products comprised of a single production facility and multiple customers, with the aim of optimally coordinating important and interrelated decisions of production sequencing and vehicle routing. Then, I propose a hybrid genetic algorithm incorporating several local optimization techniques, HGAP, for integrated production-distribution planning. Computational results on test problems show that HGAP is effective and generates substantial cost savings over Hurter and Buer's decoupled planning approach in which vehicle routing is first developed and a production sequence is consequently derived. Especially, HGAP performs better on the problems where customers are dispersed with multi-item demand than on the problems where customers are divided into several zones based on single-item demand.

• Journal of Digital Convergence
• /
• v.16 no.7
• /
• pp.1-8
• /
• 2018

In Korea, water supply capacity and facility investments had been emphasized around the 1980s. The water pricing have gained focuses in water policy since the 1990s. This study analyzes a water demand and estimates the relation of water demand and other socio-economic variable, using econometric models on the city of Busan. Water price and income are two key elements to explain water demand. Modeling approach using translog function provides better results, and water demand responds positively to population and income. Energy and water prices are negative factors in deciding water demand. It is requested that water pricing needs to reflect more production costs. Alternative approaches such as water saving facilities by household and use of digital water information should be emphasized for efficient water management in a local community.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1991.10a
• /
• pp.357-365
• /
• 1991

Military material-supply problem is one of the most important logistic problems under conscription system. Formally, two approaches were followed lowed to this problem. (1) Needs for material per soldier is estimated by past experience. The total demand for the material is estimated by multiplication of this coefficient and the number of soldiers given in the governmental programme. (2) The total demand for the material is estimated by the forcast based on the past statistics. The material supply system based on these estimates, however, relies too much on past statistics ;lack of flexibility is feared to adapt itself to changes in conscription programme, life-time of materials and so on. In this paper, the author has followed new approach : The conscription system itself is a linear input-output system, in which sequences of enlistment and dischargement are regarded as input and output. And the sequencial demands for the material are related by another linear transformation to the former sequences. In this regard z-transformation is applied to construct to transfer functions associated with this system. With these transfer functions, methods are established to determine the material demand corresponding to conscription programme and life-time distribution. Numerical methods by computers are also prepared.

• Journal of Korea Technology Innovation Society
• /
• v.14 no.4
• /
• pp.736-760
• /
• 2011

The importance of new renewable energy is emphasized not only new growth engine but also the key solution for the exhaustion problem of fossil energy and environment problem. For the steady growth of new renewable energy industry, securing related labor force is an essential factor. In this study, the status on labor force of new renewable energy industry was identified and forecasted the labor force demand of new renewable energy in 2015 by reflecting the industrial growth outlook on the new renewable energy. For the quantitative analysis methodology, the stock approach of Bureau of Labor Statistics (BLS) of the United States was applied. Also by performing survey on the experts, the opinions of experts on supply and demand of new renewable energy labor force or worker training programs have been gathered. As a result of study, it has been analyzed that nearly 20% annual growth rate will be shown as the labor force demand in the field of new renewable energy industry increases from 14,100 people in 2010 to 33,200 people in 2015. In the survey on experts, we could find that a plan for supplying labor force must be prepared promptly in order to accomplish new renewable energy supply objectives and industrial growth objectives by our country in the future as the supply of new renewable energy labor force is currently insufficient. Also, it has been analyzed that the effort for deciding the proper new renewable energy labor force training program standard will be necessary. This study result could be used as a material of labor force training plan for the steady growth of new renewable energy industry in the future.

• The Journal of Asian Finance, Economics and Business
• /
• v.7 no.7
• /
• pp.241-249
• /
• 2020

The role of money in the modern economy highly determines the intensity and the development of the macroeconomy. The money supply is assumed to be as much as money demand, which reflects the economic character of a country and indicates the growth and development of macroeconomy. In Indonesia, the money supply (M1) is related to the economic dynamics in either the monetary market or the goods market. This research aims at analyzing factors that influence the money supply and to what extent the economic factors affect the money supply in Indonesia. The analysis method used in this research was Vector Autoregressive (VAR) with some variables, such as money supply (M1), interest rate, and Gross Domestic Product (GDP) from the 1st quarter of 2001 until the 1st quarter of 2013. The data collection method was in the form of data compilation from credible sources, such as Bank of Indonesia (BI), Central Bureau of Statistics (CBS), and International Financial Statistics (IFS). To obtain adequate analysis results, several tests were taken, such as unit-root test, Granger causality test, and optimal lag. VAR analysis formulates the correlation among independent variables, so it also sees the study of impulse response and matrix decomposition.

• Journal of Information Technology Applications and Management
• /
• v.11 no.3
• /
• pp.1-21
• /
• 2004

To meet the needs of the information age, the Korean government has placed a high priority in building the IT -capable workforce. Though a sizable financial resource was committed in implementing the policy, its effectiveness was not examined yet. The policy for the workforce development should be assessed continuously so that any misdirections are detected and redressed. The present study addresses four potential problems that would not allow the government to switch from a quantity-based policy to a quality-based policy. These are ① Korean universities' labor supply chain. ② moral hazard problems. ③ financial capacity of students, ④ horizontal policy orientation. The paper also proposes solutions to the mentioned problems. The government should foster an environment in which provide the concerned parties(universities. private institutions. students. etc,) with incentives to participate actively and promote the market principle of labor supply and demand. Such an ex-ante approach is believed to improve the system's efficiency compared to the extant approach based on ex-post KPI figures. If the four issues are not redressed. the market failure is likely to occur. The government should not make direct involvement in developing manpower, but rather be a linchpin to pull all concerned parties together. By doing so. the government should be able to fill the gap among parties in the system. One government role would be like defining workforce categories and promoting their career paths. Such role will also trigger universities and private institutions to pursue differential strategies along the supply chain of a particular workforce type.

• Journal of Fashion Business
• /
• v.11 no.4
• /
• pp.221-231
• /
• 2007

SCM system is required inter-industrial cooperation as well as inter-organizational cooperation. It means not only standardization of inter-organization but also standardization of inter-industry. SCM makes possible one circulation from fiber to retail industry in the respects of information and product flows. QR is the SCM of textile apparel industry, which satisfy customer need with least cost and maximum profit. Customer-oriented supply chain system focused on information sharing, cost reduction, inventory control, lead time reduction, quick response on customer demand. How we can measure the performance of successful SCM is issued on the approach of Balanced Scorecard which evaluates 4 perspectives such as customer perspective, internal business perspective, financial perspective, and innovation and learning perspective. This can project the blueprint of textile fashion business to right direction with vision.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2003.05a
• /
• pp.8-13
• /
• 2003

This paper considers a continuous-review two-echelon inventory control problem with one-to-one replenishment policy incorporated and with lost sales allowed where demand arrives In a stationary Poisson process The problem Is formulated using METRIC-approximation in a combined approach of pricing and (S-1.S) Inventory policy, for which an iterative solution algorithm is derived with respect to the corresponding one-warehouse multi-retailor supply chain. Specifically, decisions on retail pricing and warehouse inventory policies are made in integration to maximize total profit in the supply chain. The objective function of the model consists of sub-functions of revenue and cost (holding cost and penalty cost). To test the effectiveness and efficiency of the proposed algorithm, numerical experiments are performed The computational results show that the proposed algorithm is efficient and derives quite good decisions

• IE interfaces
• /
• v.11 no.1
• /
• pp.85-95
• /
• 1998

This study is focussed on an optimal vehicle routing model for multi-supply centers in two-echelon logistic system. The aim of this study is to deliver goods for demand sites with optimal decision. This study investigated an integrated model using step-by-step approach based on relationship that exists between the inventory allocation and vehicle routing with restricted amount of inventory and transportations such as the capability of supply centers, vehicle capacity and transportation parameters. Three sub-models are developed: 1) sector-clustering model, 2) a vehicle-routing model based on clustering and a heuristic algorithm, and 3) a vehicle route scheduling model using TSP-solver based on genetic and branch-and-bound algorithm. Also, we have developed computer programs for each sub-models and user interface with visualization for major inputs and outputs. The application and superior performance of the proposed model are demonstrated by several sample runs for the inventory-allocation and vehicle routing problems.