• Proceedings of the KSME Conference
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• 2002.08a
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• pp.225-228
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• 2002

Supersonic jet impingement on a flat plate has been investigated to show the flow physics for different jet heights and to demonstrate the adequacy of the characteristics-based flux-difference Wavier-Stokes code Current study also compares the steady-state solutions obtained with variable CFL number for different grid spacing with the time-accurate unsteady solutions using the inner iterations, displaying a good agreement between the two sets of numerical solutions. The unsteady nature of wall fluctuations due to bouncing of the plate shock is also uncovered for high pressure ratios. The methodology is then applied to a complex vertical launcher system where the jet plume hits the bottom wail, deflects into the plenum and eventually exits through the vertical uptake. Flow structures within vertical launcher system are captured and solutions are partially verified against the flight test data. Present jet impingement study thus shows the usefulness of CFD in designing a complex structure and predicting flow behavior within such a system.

• KIEAE Journal
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• v.13 no.2
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• pp.85-92
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• 2013

Regarding urban design in this 21st century, cities pursue human-oriented urban design through which nature, cities, and human beings are unified and interact with one another. For such urban design maintenance, it is needed to conduct systematic analysis and synthesis on various and complex factors of cities expressing urban images. Also, it is necessary to secure methods to evaluate those cities based on urban users' visual information. Thereupon, this study aims to suggest urban design evaluation methods which accept human behavior or needs and also allow us to figure out desirable images. For this, the study established the construction system of the most basic urban design components that form cities through literature review and expert evaluation. And it examines correlation among those factors with statistic means. Through this, the study suggests a new urban design evaluation system and evaluation process divided into experts and users so as to reflect user behavior or needs.

• Journal of Convergence Society for SMB
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• v.1 no.1
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• pp.75-83
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• 2011

Unified Modeling Language (UML) is widely accepted in industry and particularly UML State Machine Diagram is popular for describing the dynamic behavior of classes. This paper discusses deadlock detection of System using UML State Machine Diagram. Since a State Machine Diagram is used for indivisual class' behavior, all the State Machine Diagrams of the classes in the system are combined to make a big system-wide State Machine Diagram to describe system behavior. Generally this system-wide State Machine Diagram is very complex and contains invalid state and transitions. To make it a usable and valid State Machine Diagram, synchronization and externalization are applied. The reduced State Machine Diagram can be used for describing system behavior thus conventional model-checking technique can be applied. This paper shows how deadlock detection of system can be applied with simple examples. All the procedures can be automatically done in the tool.

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.215-220
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• 1990

A.C. impedance properties of $RuO_2$ based thick film resistors which having different resistivity value (DuPont 1721 : $100{\Omega}$/ sq., 1741 : $10K{\Omega}$/sq.) were investigated using by impedance analyzer. In case of lower resistivity 1721 system, the complex impedance was composed nearly R component for all speciman sintered at above $600^{\circ}C$, and the frequency dependancy on impedance was not affected very much up to 5MHz and again gradually increase with increasing the frequency. In case of higher resistivity 1741 resistor system, impedance properties were very depandant on sintering temperature. When sintering temperature was $600^{\circ}C$, the complex impedance plot shows a vertical line, which correspond to lone capacitance equivalant circuit, and the impedance linearly decreased with increasing frequency. In case of speciman sintered at $700-900^{\circ}C$, the complex impedance plot shows semi-circular are correspond to a lumped RC combination, and the impedance shows constant value to 5MHz, again decreased with increasing frequency. But the complex impedance behavior of speciman sintered at $1000^{\circ}C$ was shows the equivalent circuit correspont to parallel combined LCR component, and the impedance was not varied with frequency.

• Structural Engineering and Mechanics
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• v.87 no.2
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• pp.173-189
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• 2023

For a given structural geometry, the stiffness and damping parameters of the soil and the dynamic response of the structure may change in the face of an equivalent linear soil behavior caused by a strong earthquake. Therefore, the influence of equivalent linear soil behavior on the impedance functions form and the seismic response of the soil-structure system has been investigated. Through the substructure method, the seismic response of the selected structure was obtained by an analytical formulation based on the dynamic equilibrium of the soil-structure system modeled by an analog model with three degrees of freedom. Also, the dynamic response of the soil-structure system for a nonlinear soil behavior and for the two types of impedance function forms was also analyzed by 2D finite element modeling using ABAQUS software. The numerical results were compared with those of the analytical solution. After the investigation, the effect of soil nonlinearity clearly showed the critical role of soil stiffness loss under strong shaking, which is more complex than the linear elastic soil behavior, where the energy dissipation depends on the seismic motion amplitude and its frequency, the impedance function types, the shear modulus reduction and the damping increase. Excellent agreement between finite element analysis and analytical results has been obtained due to the reasonable representation of the model.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1523-1529
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• 2011

Light Rail Transit is system that offer target Performance and function because various sub-system such as vehicles, power supply, signaling, communication, mechanical, track, civil is consisted as large complex system. Light Rail Transit and the complex system of safety, reliability to be a behavior, and target performance and function properly to system's configuration, design, manufacture, installation and test verification, through operations system requirements to accurately describe what It is more important. With this study, light rail system KSX ISO/IEC 15288 system life cycle process by applying engineering techniques utilizing light rail system in the early stages of construction from the concept, design, production, operation, maintenance and end-use to the disposal stage throughout the entire life cycle, from the beginning of construction until the end of construction of the stakeholder to define requirements, analyze the introduction of the system developers and system requirement of those who wish to be described accurately by selecting the best system and system requirement in order to achieve their purpose.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.1
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• pp.67-71
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• 2009

Using driving simulator, we analyzed the driving behavior of an older driver on intersection and measured the pychological load to HRV. As a results, older drivers started to enter the more complex intersection on a great distance and on low velocity for safety driving. On the other hand, the value of HRV would be lower on more complex intersections. It suggested that an older driver allowed for his own losses of physiological and cognitive function and recognized low level of driving confidence relatively.

• International Journal of High-Rise Buildings
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• v.2 no.1
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• pp.79-83
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• 2013

Shaking table test is an important and useful method to help structural engineers get better knowledge about the seismic performance of the buildings with complex structure, just like Shanghai tower. According to Chinese seismic design guidelines, buildings with a very complex and special structural system, or whose height is far beyond the limitation of interrelated codes, should be firstly studied through the experiment on seismic behavior. To investigate the structural response, the weak storey and crack pattern under earthquakes of different levels, and to help the designers improve the design scheme, the shaking table model tests of a scaled model of Shanghai tower were carried out at the State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University, Shanghai, China. This paper describes briefly the structural system, the design method and manufacture process of the scaled model, and the test results as well.

• Journal of Korean Academy of Nursing
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• v.33 no.2
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• pp.275-283
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• 2003

Purpose: This study was to classify elderly in long-term care hospitals for using Resource Utilization Group(RUG-III) and to consider feasibility of payment method based on RUG-III classification system in Korea. Method: This study designed by measuring resident characteristics using the Resident Assessment Instrument-Minimum Data Set(RAI-MDS) and staff time. The data were collected from 382 elderly over sixty-year old, inpatient in the five long-term care hospitals. Staff time was converted into standard time based on the average wage of nurse and aids. Result: The subjects were classified into 4 groups. The group of Clinically Complex was the largest(46.3%), Reduced Physical Function(27.2%), Behavior Problem(17.0%), and Impaired Cognition(9.4%). The average resource use for one resident in terms of care time(nurses, aids) was 183.7 minutes a day. Relative resource use was expressed as a case mix index(CMI) calculated as a proportion of mean resource use. The CMI of Clinically Complex group was the largest(1.10), and then Reduced Physical Function(0.93), Behavior Problem(0.93), and Impaired Cognition(0.83) followed. The difference of the resource use showed statistical significance between major groups(p<0.0001). Conclusion: The results of this study showed that the RUG-III classification system differentiates resources provided to elderly in long-term care hospitals in Korea.

• Korean System Dynamics Review
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• v.1 no.2
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• pp.91-111
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• 2000

Causal maps or cognitive maps have been widely used to get insights for complex systems or decision makers. When insights come from the system behavior rather than its structure, we need simulation of causal maps and cognitive maps. In this paper, a method for directly converting causal maps and cognitive maps into stock-flow diagrams that can be simulated in computers in proposed. This method is called as NUMBER. NUMBER is an abbreviation for 'Normal Unit Modeling By Elementary Relationship'. In this paper, NUMBER is applied to a cognitive map of policy maker to show its usefulness.