• Journal of Korean Society of Transportation
• /
• v.23 no.3 s.81
• /
• pp.73-84
• /
• 2005

Highway design criteria are considering roadway safety and smooth driving maneuver. However, a certain highway alignment within design criteria often leads drivers to undesirable situation due to the differences between the original intention of design criteria and the unintended result of drivers' cognition. The differences between them often result in traffic accidents. In order to reduce accident process, highway safety facilities are installed on those roadway sections. However, the relationship between highway environments and human factors has not been deeply studied in Korea. In this study. vertical roadway sections are constructed with 3-D graphical tools. This vertical roadway sections are simulated on a driving simulator in order to identify the differences of drivers' cognition on different roadway environments. Based upon the collected data from the driving simulator, canonical correlation analysis and canonical discriminant analysis of quantification theory II have been performed in order to figure out impacting factors on the degree of roadway safety. Also, based upon quantification theory I. the relationship between roadway safety facilities and the degree of safety has been analyzed.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.933-937
• /
• 2002

The fiber reinforced composite material is widely used in the multi-industrial field where the weight reduction of the infrastructure is demanded because of their high specific modulus and specific strength. Pressure vessels using this composite material in comparison with conventional metal vessels can be applied in the field where lightweight and the high pressure are demanded from the defense and aerospace industry to rocket motor case due to the merits which are energy cutdown the weight reduction and decrease of explosive damage preceding to the sudden explosion which is generated by the pressure leakage condition). In this paper, for nonlinear finite element analysis of E-glass/epoxy filament winding composite pressure vessel receiving an internal pressure, the standard interpretation model is developed by using the ANSYS, general commercial software, which is verified as the accuracy and useful characteristic of the solution based on Auto LISP and ANSYS APDL. Both the preprocessor for doing exclusive analysis of filament winding composite pressure vessel and postprocessor that simplifies result of analysis have been developed to help the design engineers.

• Microbiology and Biotechnology Letters
• /
• v.20 no.5
• /
• pp.597-606
• /
• 1992

Effects of dilution rate, inlet glucose and ammonium chloride concentrations on ,he performance of continuous culture of Alcaligenes eutrQPhus for poly-p-hydroxybutyrate (PHB) production were investigated. When inlet substrate concentrations were maintained constant (inlet glucose concentration = 20 g/l, inlet ammonium chloride concentration = 2 g/l), growth rate of residual biomass and PHB production rate showed its maximum at $0.1h^{-1}$ and $0.06h^{-1}$, respectively, and washout at $0.13h^{-1}$. PHB content decreased from 50% to 25% by increasing dilution rate, while specific PHB production rate increased continuously. Cell mass and PHB concentration gave its maximum values at inlet ammonium chloride concentration of 2 g/l and thereafter decreased, which showed the existence of substrate inhibition by ammonium. When inlet glucose concentration was 30 g/l, cell mass reached its maximum value, while PHB concentration increased continuously. The parameters of kinetic model were evaluated by the graphical and parameter estimation methods. The computer simulation results for the effects of dilution rate, inlet glucose and ammonium chloride concentrations fitted the experimental data very well.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.32 no.9
• /
• pp.315-324
• /
• 1983

Dynamic stability problems have been experienced with a generator connected to an infinite bus through a long transmission line. Nuclear turbine-generator units #1 and #2 at the Winsconsin Electric Power Point Baech Station were found to be dynamically unstable when one unit is isolated on one of the lines to Milwaukee or when two units are isolaed on the lines to milwaukee. Power System Stabilizers(PSS) were applied to the excitation system to provide stable operation under these conditions. Suitable settings for the PSS were predetetermined analytically by computer method and root licus analysis of an equivalent single machine-infinite bus configuration. This procedure allows graphical approach to the design of power stabilizers and serves as assynthesis procedure when the design constraints are relaxed so the the speed stabilizer is required ro provide animprovement in system damping. A simplified model of the complete exciter generator system is shown to be adequate for this type of analysis.

• Journal of Environmental Health Sciences
• /
• v.35 no.6
• /
• pp.491-499
• /
• 2009

The removal of turbidity from $TiO_2$ wastewater by an electrocoagulation/flotation process was studied in a batch reactor. The response surface methodology (RSM) was applied to evaluate the simple and combined effects of the three main independent parameters, current, NaCl dosage and initial pH of the $TiO_2$ solution on the turbidity removal efficiency, and to optimize the operating conditions of the treatment process. The reaction of electrocoagulation/flotation was modeled by use of the Box-Behnken method, which was used for the fitting of a 2nd order response surface model. The application of RSM yielded the following regression equation, which is an empirical relationship between the turbidity removal efficiency of $TiO_2$ wastewater and test variables in uncoded unit: Turbidity removal (%)=69.76+59.76Current+11.98NaCl+4.67pH+5.00Current${\times}$pH-160.11$Current^2-0.34pH^2$. The optimum current, NaCl dosage and pH of the $TiO_2$ solution to reach maximum removal rates were found to be 0.186 A, 0.161 g/l and 7.599, respectively. This study clearly showed that response surface methodology was one of the most suitable method to optimize the operating conditions for maximizing the turbidity removal. Graphical response surface and contour plots were used to locate the optimum point.

• Nuclear Engineering and Technology
• /
• v.36 no.1
• /
• pp.24-35
• /
• 2004

In order to analyze the hydrogen distribution during a severe accident in the APR1400 containment, GASFLOW II was used. For the APR1400 NPP, a hydrogen mitigation system is considered from the design stage, but a fully time-dependent, three-dimensional analysis has not been performed yet. In this study GASFLOW code II is used for the three-dimensional analysis. The first step to analysis involving hydrogen behavior in a full containment with the GASLOW code is to generate a realistic geometry model, which includes nodalization and modeling of the internal structures such as walls, ceilings and equipment. Geometry modeling of the APR1400 is conducted using GUI program by overlapping the containment cut drawings in a graphical file format on the mesh view. The total number of mesh cells generated is 49,476. And the calculated free volume of the APR1400 containment by GASFLOW is almost the same as the value from the GOTHIC modeling. A hypothetical SB-LOCA scenario beyond design base accident was selected to analyze the hydrogen behavior with the hydrogen mitigation system. The source of hydrogen and steam for the GASFLOW II analysis is obtained from a MAAP calculation. Combustion pressure and temperature load possibilities within the compartments used in the GOTHIC analysis are studied based on the Sigma-Lambda criteria. Finally the effectiveness of HMS installed in the APR1400 containment is evaluated from the point of severe accident management

• Journal of the Korea Convergence Society
• /
• v.8 no.6
• /
• pp.17-27
• /
• 2017

Recently, as cyber attacks have been activated, many such attacks have come into contact with various media. Research on security engineering and reverse engineering is active, but there is a lack of research that integrates them and applies attack systems through cost effective attack engineering. In this paper, security - enhanced information systems are developed by security engineering and reverse engineering is used to identify vulnerabilities. Using this vulnerability, we compare and analyze lifecycle models that construct or remodel attack system through attack engineering, and specify structure and behavior of each system, and propose more effective modeling. In addition, we extend the existing models and tools to propose graphical attack specification models that specify attack methods and scenarios in terms of models such as functional, static, and dynamic.

• Journal of Construction Engineering and Project Management
• /
• v.1 no.3
• /
• pp.1-8
• /
• 2011

Available data on the recent global financial crisis (GFC) show that it lasted between the second quarter (Q2) of 2007 and the fourth quarter (Q4) of 2009. Australia is one of the first economies to fully recover from this crisis. This study explorles the role played by the Australian construction industry in stimulating economic growth during the recession. In order to investigate the macro-variability trend during the financial crisis, data were collected and analysed relating to the quarterly GDP of Australia and selected countries between Q1 2000 and Q4 2009. Specifically, changes in the construction industry's GDP were compared with aggregate GDP changes in Australian economy and similar indices in the 'Group of 7' (G7) countries and Organisation for Economic Co-operation and Development (OECD) countries. Moreover, specific attention was focused on Germany, France, Japan, United States of America (USA) and United Kingdom (UK). Graphical and Pearson's correlation methods were used to analyse the relationships between changes in construction GDP and Australia's overall economic growth during the recession. In addition, an attempt was made to develop a regression model for predicting economic growth during the recent recession using changes in gross fixed capital formation (GFCF), changes in construction GDP and the impact of these changes on national economy. Analysis shows a slight contraction in construction activities during the crisis; however construction triggered significant growth in the economy during the crisis period and afterwards. This appears to be the major difference between Australia and other major economies that have experienced a longer recession.

• Advances in nano research
• /
• v.7 no.5
• /
• pp.293-310
• /
• 2019

In this paper, thermal-buckling behavior of the functionally graded (FG) nanocomposite plates reinforced with graphene oxide powder (GOP) is studied under three types of thermal loading once the plate is supposed to be rested on a two-parameter elastic foundation. The effective material properties of the nanocomposite plate are considered to be graded continuously through the thickness according to the Halpin-Tsai micromechanical scheme. Four types of GOPs' distribution namely uniform (U), X, V and O, are considered in a comparative way in order to find out the most efficient model of GOPs' distribution for the purpose of improving the stability limit of the structure. The governing equations of the plate have been derived based on a refined higher-order shear deformation plate theory incorporated with Hamilton's principle and solved analytically via Navier's solution for a simply supported GOP reinforced (GOPR) nanocomposite plate. Some new results are obtained by applying different thermal loadings to the plate according to the GOPs' negative coefficient of thermal expansion and considering both Winkler-type and Pasternak-type foundation models. Besides, detailed parametric studies have been carried out to reveal the influences of the different types of thermal loading, weight fraction of GOP, aspect and length-to-thickness ratios, distribution type, elastic foundation constants and so on, on the critical buckling load of nanocomposite plates. Moreover, the effects of thermal loadings with various types of temperature rise are investigated comparatively according to the graphical results. It is explicitly shown that the buckling behavior of an FG nanocomposite plate is significantly influenced by these effects.

• Journal of Digital Convergence
• /
• v.17 no.9
• /
• pp.39-46
• /
• 2019

This study started with the question of whether the percentage of non-aeronautical revenues at Incheon airport was extremely high when compared with other international airports. Although aeronautical revenues for the airport based on the traditional business model have the limits to grow due to various regulations, stakeholders concerned about improving the competitiveness recently have been interested in increasing non-aeronautical revenues. This study deals with the effect of non-aeronautical revenues at international airports on airport charges as the extent of airport privatization get stronger. To examine hypotheses, we collected international data from trustful sources. Finally, we conducted an empirical analysis of 178 airports worldwide. As a result, the higher the percentage of non-aeronautical revenues at international airports, the lower the airport charges were. Besides, the private equity ratio positively moderated the relationship between the percentage of non-aeronautical revenues and airport charges. Privatization of airports may offset the effects of reduced airport charges through increased commercial activity. Graphical display for moderation effect is offered to facilitate comprehension.