• Environmental Engineering Research
• /
• v.17 no.1
• /
• pp.27-34
• /
• 2012

This paper deals with the evaluation of environmental impact of rail and road transport in South Korea. A framework of energy input-output analysis is employed to estimate the total energy consumption and $CO_2$ emission in acquiring and using a life cycle of passenger and freight transport activity. The reliability of $CO_2$ emission based on uncertainty values is assessed by means of a Monte Carlo simulation. The results show that on a passenger-kilometers basis, passenger roads have life cycle emissions about 1.5 times those of rail, while that ratio is ten times greater when the scope of evaluation regards the tailpipe. In the case of freight transport, on a million ton-kilometers basis, the value for road mode is estimated to be about three times compared to those of rail mode. The results also show that the main contribution of $CO_2$ emission for road transport is the operation stage, accounting for 70%; however, the main contribution for rail transport is the construction and supply chain stage, accounting for over 50% emission.

• Journal of the Korean Regional Science Association
• /
• v.15 no.3
• /
• pp.1-13
• /
• 1999

Since the 1990's, the most important environmental issue on the earth is characterized by "global worming problem". The United Nations Framework Convention on Climate Change (UNFCCC) plays an significant role to solve this problem on a worldwide scale. The main purpose of this paper is to analyse the impact of $CO_2$ reduction on the Daegu regional economy through 1995 regional input-output coefficients derived from the 1995 national input coefficients table by using non-survey method. The sectoral impacts on output, income, and employment were computed under the decline-unequalized assumption in final demand influenced by $CO_2$ reduction. This article has six main sections. Section 1 is an introduction to this paper. Section 2 explains briefly the derivation method of the regional technical coefficients. Section 3 describes the model building through input-output multipliers. In section 4 regional data on output, income, employment and final demand are computed to estimate the regional impacts. Section 5 deals with impact analysis on the Daegu economy. Section 6 contains a brief summary and concludintg remarks. The research findings of this study can be summarized as follows. In 1995, under the assumption of 10% decrease on an average in final demand sectors, the economy of the region studied decreased \3600 billion of output, ￦1114 billion of income, and 49919 man-years of employment. The percent ratios of each value to the total showed 9.4%, 9.7%, and 9.2%, respectively. The dominant sectors associated with impact analysis within the region are chemicals and chemical products, paper, printing and publishing, and textiles and leather, etc; nevertheless, the least dominant sector is non-metallic mineral products. products.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.73-76
• /
• 2009

LCA is nowadays getting popular as a tool to assess the environmental impacts. We can assess the environmental impacts of products and also compare the environmental performance between products with LCA. Furthermore, the LCA results can be used for designing eco-friendly products. But LCA needs an enormous amount of data collection, calculations of energy and material balance. which required to spend pretty much time and cost. However, If we use Input-Output Analysis, There is a lot of advantages that we can save time and cost to calculate and also analyze energy-material balance more comprehensively. Therefore, we implemented the fundamental research of the environmental impact assessment on railway system using life cycle inventory analysis and Input-Output Analysis method.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.11
• /
• pp.98-105
• /
• 1999

As the IC(Integrated Circuit) has been densified and complicated, it is required to thorough process control to improve yield. Experts, for this purpose, focused on the process analysis automation, which is came from the strict data management in semiconductor manufacturing. In this paper, we presents the process analysis system that can analyze causes, for a output after processes. Also, the plasma etching process that highly affects yield among semiconductor process is modeled to predict a output before the process. To approach this problem, we use adaptively trained neural networks that exhibit superior accuracy over statistical techniques. And in comparison with methods in other paper, a method that history of trend for input data is considered is shown to offer advantage in both learning and prediction capability. This research regards CD(Critical Dimension) that is considerable in high integrated circuit as output variable of the prediction model.

• Nuclear Engineering and Technology
• /
• v.53 no.2
• /
• pp.637-646
• /
• 2021

The free-piston Stirling engine (FPSE) has been widely used in aerospace owing to its advantages of high efficiency, high reliability, and self-starting ability. In this paper, a 20-kW FPSE is proposed by analyzing the requirements of space nuclear power reactor. A code was developed based on an improved simple analysis method to evaluate the performance of the proposed FPSE. The code is benchmarked with experimental data, and the maximum relative error of the output power is 17.1%. Numerical results show that the output power is 21 kW, which satisfies the design requirements. The results show that: a) reducing the pressure shell's thickness can improve the output power significantly; b) the system efficiency increases with the wire porosity, while the growth of system efficiency decreases when the porosity is higher than 80%, and system efficiency exhibits a linear relationship with the temperatures of the cold and hot sides; c) the system efficiency increases with the compression ratio; the compression ratio increases by 16.7% while the system efficiency increases by 42%. This study can provide valuable theoretical support for the design and analysis of FPSEs for space nuclear power reactors.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1994.04a
• /
• pp.437-450
• /
• 1994

The problem of testing for a change in the parameter of a stochastic process is particularly important in simulation studies. In studies of the steady state characteristics of a simulation model, it is important to identify initialization bias and to evaluate efforts to control this problem. A simulation output have the characteristics of chaotic behavior because of sensitive dependence on initial conditions. For that reason, we will apply Lyapunov exponent for diagnosis of chaotic motion to simulation output analysis. This paper proposes two methods for diagnosis of steady state in simulation output. In order to evaluate the performance and effectiveness of these methods using chaos theory, M/M/I(.inf.) queueing model is used for testing point estimator, average bias.

• New & Renewable Energy
• /
• v.16 no.4
• /
• pp.76-82
• /
• 2020

Soiling on the surface of a PV module reduces the amount of light reaching the solar cells, decreasing power performance. The performance of the PV module is generally restored after contaminants on the module surface are washed away by rain, but it accumulates at the bottom of the module owing to the thickness of the module frame, causing an output mismatch on the PV module. Since PV modules are usually installed horizontally or vertically outdoors, soiling can occur at the bottom of the PV module, depending on the installation direction due to external environmental factors. This paper is analyzed the output characteristics of a PV module considering its installation direction and the soiling area. The soiling was simulated to use transparent films with 5% transmittance, and the transmission film was attached to the bottom part of the PV module horizontally and vertically. When the soiling area was 33% of the string at the bottom of the PV module, the power output decreased similarly regardless of installation direction. However, when the soiling area was 66% of the string at the bottom of the PV module, it was confirmed that the output performance decreased sharply when installed vertically rather than horizontally.

• Journal of Electrical Engineering and Technology
• /
• v.8 no.1
• /
• pp.150-155
• /
• 2013

A high voltage and nanosecond Blumlein pulse generator has been developed to produce an output pulse whose voltage level is greater than 250 kV and pulse duration 5 ns. The generator consists of various components such as a charging circuit, a pulse transformer, and a spark gap switch. As a heart of the generator, a Blumlein pulse forming line has been constructed in the cylindrical form using three cylindrical aluminum electrodes that are placed concentrically. Unlike the ideal Blumlein line, the output pulse of an actual Blumlein line may be affected by stray inductances and capacitances of switching and charging components, thereby degrading the performance of the generator. In this paper, PSPICE simulations have been performed to examine effects of stray inductances and capacitances on waveforms of output pulses. Simulation results show that the pulse waveform is significantly distorted mainly by the stray inductance of the spark gap switch.

• Journal of Society of Preventive Korean Medicine
• /
• v.8 no.1
• /
• pp.163-186
• /
• 2004

The purpose of this parer is to identify the input-output structure of oriental medicine and its alternative medicine industries in an inter-industry context and to estimate its forward and backward effects on macroeconomic variables such as production, employment and price level. Input-output tables released by The Bank of Korea were used as data in this research and inter-industry analysis was adopted as research methodology. The industry takes less share of production, price and trade in a Korean economy, compared with other industry. However, the industry's capability of creating value added is estimated to be well above that of other industry and that of making new employments is as more than 4 times as other industries. This result gives us policy implications that the government should enhance its subsidy policy and economic (tax) incentives for oriental medicine and its related alternative medicine industries.

• 한국태양에너지학회:학술대회논문집
• /
• 2012.03a
• /
• pp.494-497
• /
• 2012

A methodology to predict the output performance of small hydro power using treated effluent in wastewater treatment plant has been studied. Existing plant located Kyunggi-Do were selected and the output performance characteristics for these plants were analyzed. As a result, it was found that the developed model in this study can be used to analyze the output characteristics for small hydro power in wastewater treatment plant. Additionally, primary design specifications such as design flowrate, capacity, operational rate and annual electricity production were estimated and discussed.