• Journal of the Korean Data and Information Science Society
• /
• v.15 no.2
• /
• pp.355-365
• /
• 2004

Kim et al.. (2003) developed an Economic Instability Index (EII) by using mean squared error (MSE) from the neural network (NN) trained on the 1995 KOSPI. In this paper we study validity of the NN. For this we compare the NN with the well known Box-Jenkins linear auto-regressive processes. Our conclusive understanding of the problem is that the NN provides quite effective EII because it tends to overfit.

• Korean Journal of Agricultural Science
• /
• v.49 no.1
• /
• pp.77-91
• /
• 2022

North-South Korea economic integration is progressing slowly given the sensitive responses to changes in internal and external conditions. Nevertheless, advanced discussions focusing on North-South Korean economic cooperation should continue. Given this background, various studies of the economic effects of economic integration between North and South Korea have been conducted, but research on agricultural issues has been limited. The purpose of this study is to analyze the impact of the economic integration of South and North Korea on the agricultural market. In this study, a simultaneous equation model was constructed using a growth model. Solow's growth accounting approach is used to construct a model for estimating the macroeconomic effect of North-South economic integration. Also, the construction of growth accounting formulas subdivided into South and North Korea as well as agriculture and non-agricultural fields during the construction of the growth model is a major research achievement and differentiates it from previous studies. It is expected that the results of this study will serve as basic information for preparing policy measures to promote integration. However, there are many limitations when estimating the economic effects of North-South agricultural integration and obtaining policy implications given the insufficient available statistical data on agriculture in North Korea and the lack of related studies in the agricultural field. Therefore, it should be noted that there is an inherent problem in that the analysis results vary greatly depending on the assumptions set, as there is inevitably no choice but to rely on many and strong assumptions.

• Journal of the Korean Mathematical Society
• /
• v.38 no.6
• /
• pp.1275-1284
• /
• 2001

In this paper, we introduce an iteration generated by countable nonexpansive mappings and prove a weak convergence theorem which is connected with the feasibility problem. This result is used to solve the problem of finding a solution of the countable convex inequality system and the problem of finding a common fixed point for a commuting countable family of nonexpansive mappings.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.50 no.7
• /
• pp.318-323
• /
• 2001

This paper proposes an efficient method of On-Line Economic Load Dispatch(ELD) using Evolutionary Programming(EP) technique at KwangYang steel works. The economic operation of steel works is done by experienced engineer. So far, there is no formulation and algorithm of economic operation of steel works. In this paper, we propose the formulation and On-Line algorithm of economic operation of steel works. The EP technique is the kind of Evolutionary Computation(EC), which has become a candidate for many optimization applications due to its flexibility and efficiency. Based on the EP technique, the proposed algorithm is capable of not only solving the economic problem, but also obtaining the global optimal solutions within reasonable execution time. To validate our proposed approach, the algorithm is demonstrated on many sample systems and compared to actual values of steel works.

• Proceedings of the KIEE Conference
• /
• 2000.11a
• /
• pp.116-118
• /
• 2000

This paper proposes an efficient method of On-Line Economic Load Dispatch(ELD) using Evolutionary Programming(EP) technique at Kwangyang steel works. The economic operation of steel works is done by experienced engineer. So far, there is no formulation and algorithm of economic operation of steel works. In this paper, we propose the formulation and On-Line algorithm of economic operation of steel works. The EP technique is the kind of Evolutionary Computation(EC) which has become a candidate for many optimization applications due to its flexibility and efficiency. Based on the EP technique, the proposed algorithm is capable of not only solving the economic problem, but also obtaining the global optimal solutions within reasonable execution time. To validate our proposed approach, the algorithm is demonstrated on many sample systems and compared to actual values of steel works.

• Proceedings of the KSEEG Conference
• /
• 2000.04b
• /
• pp.203-204
• /
• 2000

• Journal of the Korean Society of School Health
• /
• v.21 no.2
• /
• pp.35-46
• /
• 2008

Purpose: This study was a part of preliminary survey for establishing Korean HPS(Health Promoting School) model which was originally suggested by WHO. Methods: Three elementary and middle schools were sampled in urban and rural area across three level of social-economic status, and survey was conducted on one class in each grade by random selection. To measure mental health and social and familial factors, self-esteem scale, self-efficacy scale, depression scale, family cohesion scale, parent-child communication scale, adolescent's mental health and problem behavior questionnaire(AMPQ), and other question items about family status and economic level were conducted. Students' mental health level was compared by region, sex, grade, and other familial and economic factors. Results: Familial and social factors such as economical and educational level of parents, number of family members were different between rural and urban area. Also, students of rural area got lower scores at self-esteem, self-efficacy, but higher scores at extroverted problem behavior than their urban counterparts. In pre-school students, high grade students' self-esteem, and family cohesion scores were lower than low grade students. And sexual differences were found across problem behavior domain and region in middle school students. Especially, the students of single-parent family and lower economic family got insistently low scores at various mental health related scales. Conclusion: These results should be considered, when the HPS model is designed and applied in Korea.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.2
• /
• pp.255-262
• /
• 2015

In the absence of a deterministic algorithm for economic load dispatch optimization problem (ELDOP), existing algorithms proposed as solutions are inevitably non-deterministic heuristic algorithms. This paper, therefore, proposes a balance-and-swap algorithm to solve an ELDOP. Firstly, it balances the initial value to ${\Sigma}P_i=P_d$ by subsequently reducing power generation for each adult-step and baby-step and selects the minimum cost-generating method. Subsequently, it selects afresh the minimum cost-generating method after an optimization of the previously selected value with adult-step baby-step swap and giant-step swap methods. Finally, we perform the $P_i{\pm}{\beta}$, (${\beta}=0.1,0.01,0.001,0.0001$) swap. When applied to the 3 most prevalently used economic load dispatch problem data, the proposed algorithm has obtained improved results for two and a result identical to the existing one for the rest. This algorithm thus could be applied to ELDOP for it has proven to consistently yield identical results and to be applicable to all types of data.

• Korean Journal of Agricultural Science
• /
• v.43 no.3
• /
• pp.481-495
• /
• 2016

Lily, which is one of Korea's main flower exports, is one of the most important agricultural product in the country. Korean lily farmers have difficulty earning more profit from producing lilies, because of the high cost of lily bulbs. Most lily bulbs used in Korea are imported from the Netherlands. Thus, the Korean government has kept trying to supply more and better Korean lily bulbs. However, many experts have questioned the efficiency and economic value of the Korean lily production system. The purpose of this paper is to analyze the economic value of the production of lily bulbs in Korea. Especially, this study evaluates the economic value of the production systems of Korean lily bulbs and compares the results from several cases. The results of the present study presents some useful findings, as follows: first, two Korean production areas (Gangneung and Jeju) show a positive economic value but one Korean production area (Taean) presents problems causing a negative economic value. Second, the Korean production area in Vietnam currently has trouble in the view of economic value but will likely overcome that problem. Third, the production area in the Netherlands shows the best economic value. Thus, Korean lily bulb producers need to benchmark that system.

• Journal of Electrical Engineering and Technology
• /
• v.8 no.3
• /
• pp.490-498
• /
• 2013

This paper discusses the application of evolutionary multi-objective optimization algorithms namely Non-dominated Sorting Genetic Algorithm-II (NSGA-II) and Modified NSGA-II (MNSGA-II) for solving the Combined Economic Emission Dispatch (CEED) problem with valve-point loading. The valve-point loading introduce ripples in the input-output characteristics of generating units and make the CEED problem as a non-smooth optimization problem. IEEE 57-bus and IEEE 118-bus systems are taken to validate its effectiveness of NSGA-II and MNSGA-II. To compare the Pareto-front obtained using NSGA-II and MNSGA-II, reference Pareto-front is generated using multiple runs of Real Coded Genetic Algorithm (RCGA) with weighted sum of objectives. Furthermore, three different performance metrics such as convergence, diversity and Inverted Generational Distance (IGD) are calculated for evaluating the closeness of obtained Pareto-fronts. Numerical results reveal that MNSGA-II algorithm performs better than NSGA-II algorithm to solve the CEED problem effectively.