• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.12 no.1
• /
• pp.38-44
• /
• 2003

In this study, endurance limit and fatigue behavior of load carrying fillet welded cruciform joints depending on commonly used welding methods such as SMAW, SAW, MIG and FCAW are investigated. In respect of endurance limit SMAW specimen showes highest result, and then MIG, SAW, FCAW in descending order. However, SMAW specimen showes lowest crack growth rate and it followed by MIG, FCAW, SAW. By these results, it is needed to use SMAW or MIG welding methods for welding structures with small welding capacity and SAW or FCAW methods for large welding structures with respect to economic benefits and operation efficiency of welding. It was also shown fatigue crack growth rate was more influenced by the strenght of welding materials than the endurance limit of welding materials.

• Journal of Korean Institute of Industrial Engineers
• /
• v.34 no.3
• /
• pp.337-343
• /
• 2008

The problem of determining the optimum metal plating thicknesses on the plane and curved surfaces of an electronic part is considered. A lower specification limit for the plating thickness is usually pre-specified. In most applications, the plating thickness on the curved surface is proportional to that on the plane surface. The proportion can be adjusted by adding chemical catalysts to the plating fluid. From the economic point of view, nonconforming items with a thickness smaller than the lower specification limit incur rejection costs, such as rework and scrap costs, while a thicker plating may incur an excessive material costs. In this article, an economic model is proposed for simultaneously determining the target plating thickness and the ratio of the plating thickness on the plane surface to that on the curved surface. An illustrative example demonstrates the applicability of the proposed model.

• Journal of Electrical Engineering and Technology
• /
• v.2 no.3
• /
• pp.342-345
• /
• 2007

This paper presents an engineering approach to derive the optimum price levels of transacted power. In this paper, with the assumption that power import is possible through the system connection in Northeast Asia regions, the upper price limit of imported power deserving economic efficiency was derived with respect to the time and amount of power import. The proposed approach was demonstrated based on the data from the National Power Development Planning in 2004 with the WASP model.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.14 no.5
• /
• pp.547-559
• /
• 2012

The concrete structural design in domestic has based on the allowable stress design (ASD) method and ultimate strength design (USD) method. Recently limit state design (LSD) method has issued and attempted to adopt in geotechnical design. Because ASD method and USD method have restriction in economic design. In this study, the generated member forces were calculated about high strength concrete segment lining based on japanese LSD code. And it compared with domestic USD code for identifying the economic design possibility of LSD and domestic applicability. In analysis results, the aspect of moment had generated similarly each other but the member forces of japanese LSD code were decreased (26.0% of moment and 26.7% of shear force) comparing with USD method. For that reason, possibility of economic segment design with stable condition were identified.

• Iberoamérica
• /
• v.12 no.2
• /
• pp.1-25
• /
• 2010

This paper explains how the political elites limit peruvian politics after independence, through examining the historical origin of elites, the formation of the dominant elites and their politicization in Peru, 1824-1919. In detail, the first section of this paper examines theoretical concepts and the political economic conditions of elites. The next part explores the emergence of the dominant elite group and their politicization, which is focused on economic incentives and conditions in the Guano era. Finally, this paper suggests that peruvian elite group after independence is politically motivated by the direct control of economic resources and maximized privilege in distributions of economic benefits. Furthermore, these features provided the archetype of the Peruvian politics, such as the pre-modern oligarchy and the military intervention.

• Journal of Korean Society for Quality Management
• /
• v.31 no.2
• /
• pp.117-130
• /
• 2003

This paper investigates the economic design of synthetic control charts. The synthetic control chart has been proven to be statistically superior to the $\bar{X}$-control chart, but its economic characteristics have not been known. We develop an economic model of the synthetic control chart, based on Duncan's model. The synthetic chart has one more decision variable, the lower control limit for the conforming run length. In addition to this, the significance level and the power of the synthetic chart are more complicated than those of the $\bar{X}$-chart. These features make the optimization problem more difficult. We propose an optimization algorithm by adapting the congruent gradient algorithm. We compare the optimal cost of the synthetic chart with that of (equation omitted)-control chart, under the same input parameter set of Duncan’s. For all cases investigated, the synthetic chart shows superior to the $\bar{X}$-chart. The synthetic control chart is easy to implement, and it has better characteristics than the $\bar{X}$-chart in economical sense as well as in statistical sense, so it will be a good alternative to the traditional control charts.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.4
• /
• pp.1441-1452
• /
• 2015

This paper proposes a new Hybrid Particle Swarm Optimization (HPSO) method that integrates the Evolutionary Programming (EP) and Particle Swarm Optimization (PSO) techniques. The proposed method is applied to solve Economic Dispatch(ED) problems considering prohibited operating zones, ramp rate limits, capacity limits and power balance constraints. In the proposed HPSO method, the best features of both EP and PSO are exploited, and it is capable of finding the most optimal solution for the non-linear optimization problems. For validating the proposed method, it has been tested on the standard three, six, fifteen and twenty unit test systems. The numerical results show that the proposed HPSO method is well suitable for solving non-linear economic dispatch problems, and it outperforms the EP, PSO and other modern metaheuristic optimization methods reported in the recent literatures.

• Proceedings of the KOR-KST Conference
• /
• 1998.09a
• /
• pp.65-70
• /
• 1998

Economic evaluation methodologies for railway investments of China and Korea are comparatively analyzed. Chinese procedures specified in the new economic evaluation manual of 1997 were compared with those of Korea based on the economic evaluation manual of 1982. As expected those procedures reflect general economic requirements of the respective countries. Several differences in the specification are also noted. Details of the specification of Chinese procedure far exceed Korean specification, while Korean manual is rich of explanation on the fundamental theory. Differences in the procedure of calculating benefits of investments are most conspicuous, and specific requirements of carrying out a optimum opening year analysis in Korean procedure is notable. Despite of these differences in the procedure, two methodologies share same objective of ensuring selection of economically and financially sound railway projects. Both procedures of China and Korea, however, limit their evaluation scope on railways alone. Therefore, they are needed to expand scope of evaluation to encompass the idea of multi-modal or inter-modal evaluation, which will eventually contribute to build truly efficient national comprehensive transportation system.

• Journal of Korean Society for Quality Management
• /
• v.28 no.4
• /
• pp.194-203
• /
• 2000

This paper is concerned with an economic selection of both the process mean and the lower limit for a continuous production process with the quadratic loss function. It is assumed that the quality characteristic is normally distributed with a known variability. A profit model is developed which involves selling price, production cost, reprocessing cost and the cost which is incurred by imperfect quality. Methods of finding optimum values of the process mean and the lower limit are presented, and a numerical example is given.

• The Journal of Asian Finance, Economics and Business
• /
• v.8 no.3
• /
• pp.79-90
• /
• 2021

This study aims to investigate the relationship between urbanization, economic growth, energy consumption, and CO2 emissions in Indonesia. The data used in the study are time-series data for the period 1985-2017; the data utilized are sourced from World Development Indicators obtained on the World Bank database. The method uses a quantitative approach that applies the vector error correction model based on the Granger causality test. The empirical results reveal that, in the short run, there is evidence that urbanization and energy consumption can causes CO2 emissions, and they also prove that urbanization can cause energy consumption. Also, other findings prove the existence of long-run relationships flowing from energy consumption, economic growth, and CO2 emissions toward urbanization, as well as the existence of the relationship flowing from urbanization, economic growth, and CO2 emissions towards energy consumption. The results of testing the relationship between economic growth and CO2 emissions reveal that the environmental Kuznets curve hypothesis is proven in Indonesia. Thus, policies are needed to limit the impact of urbanization through high awareness-raising to maintain environmental quality and greater use of energy. Also, energy conservation policies are needed in all sectors, especially the electricity, industry, and transportation sectors.