Keunhwa Lee

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This study was undertaken to investigate the types and concentrations of microbial agents in various medical wastes as well as to characterize their survivals in these wastes at different temperatures for microbial risk assessment. Medical wastes collected from 5 major hospitals in South Korea were classified and stored at three different temperatures (-20,(More)
Acoustic measurements of p-wave speed and attenuation were made for water-saturated granular medium, consisting of six kinds of glass-beads with mean grain size ranging from 90 to 875 microm, at frequency range between 400 kHz and 1.1 MHz. Sound speed and attenuation were obtained using the inter-receiver broadband estimation technique. The measured data(More)
A closed-form solution for the effective wavenumber in a water-saturated medium as a function of the Rayleigh parameter is derived up to the second leading terms in the real part and first leading term in the imaginary part. This is based on the Waterman multiple scattering formulation with the quasicrystalline approximation (QCA) and the Percus-Yevick(More)
Range-dependence of time-varying acoustic channels caused by a traveling surface wave is investigated through water tank experiments and acoustic propagation analysis schemes. As the surface wave travels, surface reflected signals fluctuate and the fluctuation varies with source-receiver horizontal range. Amplitude fluctuations of surface reflected signals(More)
Model tests are performed in order to predict the noise level of a full ship and to control its noise signature. Localizing noise sources in the model test is therefore an important research subject along with measuring noise levels. In this paper, a noise localization method using a hydrophone array in a large cavitation tunnel is presented. The 45-channel(More)
Several acoustic models, such as the poro-elastic model, visco-elastic model, and multiple scattering model, have been used for describing the dispersion relation in a porous granular medium. However, these models are based on continuum or scattering theory, and therefore cannot explain the broadband measurements in cases where scattering and non-scattering(More)
This paper describes the results of range-dependent geoacoustic inversion using vertical line array data obtained from the 4th Matched Acoustic Properties and Localization Experiment conducted in the East Sea of Korea. The narrowband multitone continuous-wave signal from the towed source was analyzed to estimate the range-dependent geoacoustic properties(More)
This paper proposes a roll-angle estimation method for the triplet towed array using the oceanic ambient noise recorded in the mid-frequency range of 1 to 10 kHz. Here, the dominance of oceanic surface-generated noises such as wind-driven and shipping noises is expected. The ratio between the approximated phase parts of the noise-coherence function(More)
S1 © 2015 Ann & Joshua Medical Publishing Co. Ltd | Published by Wolters Kluwer Medknow O-001 The Development and Effects of Evidence based Vascular Access Port Management Education Program for Oncology Nurses in South Korea Yunjin Lee, Juhye Lee, Meeyoung Cho, Yoonjung Shin, Soyoung Bae, Jiseon Lee, Jungim Bae, Kyunghi Lee, Keunhwa Lee, Eunhee Lee,(More)
Kirchhoff formula for an impedance polygon facet is given in the time domain. The derived formula is expressed as a summation of the transient analytic functions and generalized functions and represents an impulse response of the impedance polygon facet. Current formula can be applied to transient scattering analysis of underwater objects such as fish and(More)
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