• Journal of Korean Port Research
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• v.9 no.1
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• pp.45-56
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• 1995

Investigation of the physical behavior of dredged material disposal in coastal water includes estimations of water column concentration in the receiving water, exposure time, the initial deposition pattern as well as thickness of material at the dumping fields near the estuary area. Calculation based on vertical setting and horizontal advection of single particles ignore the effects of bulk properties of the disposed material, vertical and horizontal diffusion, and material dilution due to the entrainment of ambient water during descent. This paper focuses on the spatial and temporal changes in the dumping fields for the water column and bottom at a hypothetically confined coastal water, where the ambient time-invariant velocity and density profiles are applied, within the initial time period following the instantaneous release of the dredged material. This model accounts the behavior of material after release divided into three phases: convective descent, dynamic collapse and long-term passive dispersion

• Steel and Composite Structures
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• v.36 no.6
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• pp.617-629
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• 2020

The purpose of this paper is to depict the effect of rotation and initial stress on a magneto-thermoelastic medium with diffusion. The problem discussed within memory-dependent derivative in the context of the three-phase-lag model (3PHL), Green-Naghdi theory of type III (G-N III) and Lord and Shulman theory (L-S). Analytical expressions of the considered variables are obtained by using Laplace-Fourier transforms technique. Numerical results for the field quantities given in the physical domain and illustrated graphically in the absence and presence of a magnetic field, initial stress as well as the rotation. The differences in variable thermal conductivity are also presented at different parameter of thermal conductivity. The numerical results of the field variables are presented graphically to discuss the effect of various parameters of interest. Some special cases are also deduced from the present investigation.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09a
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• pp.590-591
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• 2005

Hydrodynamic pressure fluctuations and their roles on the design of hydraulic structures has been the subject of many investigations. The studies showed that turbulent pressure fluctuations may cause serious damages to hydraulic structures. In case of high velocity flows, separation of flow from the boundary also causes the local pressure to drop and as a result, the resultant pressure fluctuations may trigger cavitation. Sever hydrodynamic pressures are also associated with the vibration of structures. Therefore, in this work, experiments were performed to determine the intensity of pressure fluctuations and their distribution along the bed of a ski-jump flip bucket. Experiments were completed on a physical model at the Institution of Water Research of Iran. The results consist of the statistical characteristics of pressure fluctuations, its maximum, minimum, and r.m.s values along the bed of the bucket. The spectral analysis of pressure fluctuations which is useful for the instability analysis of such structures is also provided. It is hoped that the present results will help the designer of such structures.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.52-59
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• 2005

The goal of this project is to estimate the instream flow of the Han River Basin to ensure the adequate supply of suitable quality water for preservation and enhancement of aquatic ecosystems. A applied model is Physical Habitant Simulation System(PHABSIM) of Instream Flow Incremental Methodology(IFIM). The parameters which are needed to simulation by PHABSIM such as flow depth, velocity distribution and channel cover with cross section data are obtained by field survey. The Habitat Suitability Criteria with the application of univariate curve on Zacco platypus as a target species was able to be established by conducting the field investigation. The estimated results of ecological recommended instream flow by this study has important meanings that the future river management have to seriously take into account for the natural environment and functions of river system.

• Journal of the Ergonomics Society of Korea
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• v.21 no.2
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• pp.13-23
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• 2002

Human dummies are essential tools in the development of such products as vehicle have been actively used not only in reach and view field tests. but also in impact perception evaluations. This study attempted to obtain geometric and dynamic model body segments from Korean anthropometric data. The investigation focused on the de both human and dummy for the geometric and inertial properties. The dynamic modeli being suggested is based on rigid body dynamics using fifteen individual body segments by joins. The segments are connected at the locations representing the physical joint body so that each segment has its mass and moment of inertia. For visual three-dimensional graphic was used for easier implementation of the dumn applications. For applications, proposed Korean dummies Were used in dynamic crash and driver's view and reach test modules were developed in virtual environment.

• Journal of Information Technology Applications and Management
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• v.16 no.2
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• pp.135-150
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• 2009

Corporate databases are usually denormalized, due to the data modelers' impetuous belief that denormalization could improve system performance. By providing a logical insight into denormalization, this paper attempts to prevent every database modeler from falling into the denormalization pit. We indicate loopholes in the denormalization advocates' assertions, and then present four criteria to analyze the usefulness and validity of denormalization; 1) the level of concurrency among transactions, 2) the database independence of the application program, 3) the independence between the logical design and the physical one, and 4) the overhead cost to maintain database integrity under various query patterns. This paper also includes experimental results to evaluate performance of denormalized and fully normalized structures under various workloads.

• Industrial Engineering and Management Systems
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• v.7 no.2
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• pp.133-142
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• 2008

The Emergency Department (ED) is an integral part of hospitals. Admissions from the ED account for a significant proportion for a hospital's activity. Ensuring a timely and efficient flow of patients through the ED is crucial for optimising patient care. In recent years, ED overcrowding and its impact on patient flow has become a major issue facing the health sector. Simulation is rapidly becoming a tool of choice when examining hospital systems due to its capacity to involve numerous factors and interactions that impact the system. An analytical simulation model is used to investigate potential impacts by changing the following aspects of ED (physical layouts; number of beds; number and rate of patient arrivals; acuity of illness or injury of patients; access to radiology and pathology services; hospital staffing arrangements; and access to inpatient beds). Results of a significant numerical investigation at a hospital are also presented.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.255.2-255.2
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• 2014

Electrode erosion is indispensable for atmospheric plasma systems, as well as for switching devices, due to the high heat flux transferred from arc plasmas to contacts, but experimental and theoretical works have not identified the characteristic phenomena because of the complex physical processes. Our investigation is concerned with argon free-burning arcs with anode erosion at atmospheric pressure by computational fluid dynamics (CFD) analysis. We are also interested in the energy flux and temperature transferring to the anode with a simplified unified model of arcs and their electrodes. In order to determine two thermodynamic quantities such as temperature and pressure and flow characteristics we have modified Navier-Stokes equations to take into account radiation transport, electrical power input and the electromagnetic driving forces with the relevant Maxwell equations. From the simplified self-consistent solution the energy flux to the anode can be derived.

• Proceedings of the Korean Geotechical Society Conference
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• 1995.10a
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• pp.201-210
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• 1995

In Resent years, urban tunnels have been more deeply constructed due to the congestion of buried steuctures. In such conditions, the shield method has become one of the popular urban tunnelling method by reason of several characteristics ; safety of construction, mimium environmental damage, and workbility. In tunnelling, the space which is tail-void are created between the ground and the other face of the primary lining. in other to reduce the ground seformation, it is important backfilling in tail-void. In this paper, the result of an experimental investigation undertaken to evaluate the physical and mechanical propeties of grouts composed of various mixtures of backfill materials. And the backfill injection model test was carried out considering the effects of tail-void.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.225-230
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• 2007

A physical model experiment with GPR and 3-D resisitivity survey were conducted to investigate the geoelectrical response of hydrocarbon-impacted zone, so called smeared zone, on the geophysical data. The results from the experiment show that GPR signals were enhanced when LNAPL was present as a residual saturation in the water saturated system (${\varepsilon}_r$ = 21) due to less attenuation of the electromagnetic energy through the medium, compared to when the medium was saturated with only water (${\varepsilon}_r$ = 21). 3-D resistivity data obtained from the former gas station site demonstrate that the highly contaminated zones could be imaged with low resistivities attributed to the biodegradation of petroleum hydrocarbons at the aged, hydrocarbon-impacted sites. The study results also show that the geophysical methods, as a non-invasive sounding technique, can be a very useful tool for mapping hydrocarbon-contaminated zones.