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  • Comparative Studies. Non-European Languages/Literatures  (13)
  • 1
    Online Resource
    Online Resource
    Communication performance analysis according to seasons in Yellow Sea.
    Acoustical Society of America (ASA) ; 2011
    In:  The Journal of the Acoustical Society of America Vol. 129, No. 4_Supplement ( 2011-04-01), p. 2667-2667
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 129, No. 4_Supplement ( 2011-04-01), p. 2667-2667
    Abstract: Communication environments vary with time in the context of underwater channel because multipaths are affected by the sound speed profile (SSP) in the ocean. In this paper, the average SSPs for 10 years (2000–2009) were calculated in the Yellow Sea so that the eigen-ray paths with the channel impulse responses were determined. The computer simulation was conducted to compare the performance of underwater communication near the surface according to the variation of season. The performance of underwater communication was analyzed using the BPSK modulation and time reversal method. The significant differences of bit error rate (BER) were shown according to the change of season. In many cases, the received signals were distorted by the multi-path channel whose features are frequency selected fading. The time reversal method was applied to compare the BER without frequency selected effect. It turns out that the good performance was shown in the autumn because of the direct path through the mixed layer channel which made the multi-path effects relatively weaker. [Work supported by UD100014DD.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.3588927
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2011
    detail.hit.zdb_id: 1461063-2
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  • 2
    Online Resource
    Online Resource
    Mobility of Amphidinium carterae Hulburt measured by high-frequency ultrasound
    Acoustical Society of America (ASA) ; 2017
    In:  The Journal of the Acoustical Society of America Vol. 141, No. 4 ( 2017-04-01), p. EL395-EL401
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 141, No. 4 ( 2017-04-01), p. EL395-EL401
    Abstract: The over-growth of phytoplankton causes harmful algal blooms (HABs) in marine ecological environments. Mobility measurement is important in understanding the action of HABs. In this study, the mobility of Amphidinium carterae Hulburt (A. carterae) was investigated using high-frequency ultrasound in the laboratory. Mobility in response to light was illustrated with M-mode images reconstructed from echoed signals. This study suggests that mobility of the swimming speed of A. carterae in response to light can be measured and calculated with M-mode images through high-frequency ultrasound. This finding may be helpful in understanding the fundamental behavior of HABs.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4980007
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2017
    detail.hit.zdb_id: 1461063-2
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  • 3
    Online Resource
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    Computation of bit error rate for underwater communication with and without low-salinity water in the western sea of Jeju.
    Acoustical Society of America (ASA) ; 2011
    In:  The Journal of the Acoustical Society of America Vol. 129, No. 4_Supplement ( 2011-04-01), p. 2667-2667
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 129, No. 4_Supplement ( 2011-04-01), p. 2667-2667
    Abstract: Salinity is one of variables in the empirical formula of the sound speed (SS) of seawater. Its effects on the SS are generally neglected because the average salinity is 34 psu and varies within a few psu seasonally and spatially in the ocean. Recently, low-salinity water around 25 psu flows into the western sea of Jeju Island in Korea due to the Yangtze River flood in China during summer. In this paper, it was analyzed how the low-salinity water affected the SS profile (SSP) and the underwater communication. The SSP was calculated with and without the low-salinity layer, and the communication channel was estimated by the simulated acoustic eigen-rays. The bit error rate (BER) was computed using binary phase-shift keying modulation, and the effects of the low-salinity water on the BER were investigated. The SSP was changed to a positive slope by the low-salinity layer at the sub-surface up to 20 m of depth, forming the acoustic wave guide which mostly resulted in the decrease of the BER. Consequently, this paper suggests that it is important to consider the low-salinity water near Jeju for the underwater acoustic modeling and communication. [Work supported by UD100014DD.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.3588926
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2011
    detail.hit.zdb_id: 1461063-2
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  • 4
    Online Resource
    Online Resource
    Measurements of diel variation of acoustic backscatter power from phytoplankton
    Acoustical Society of America (ASA) ; 2013
    In:  The Journal of the Acoustical Society of America Vol. 134, No. 5_Supplement ( 2013-11-01), p. 3990-3990
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 134, No. 5_Supplement ( 2013-11-01), p. 3990-3990
    Abstract: Phytoplankton is a primary producer in the ocean, and its vegetative activity plays an important role in controlling the global environment. In this study, the high-frequency acoustic signals were collected to evaluate the photosynthetic activity of phytoplankton during a day. The integrated backscatter power (IBP) from a dinoflagellate Cochlodinium polykrikoides was measured by a 5 MHz acoustic system during a 5-day cultivation period with a 14 h:10 h light:dark cycle. IBP increased by 0.6 dB in five days, but varied by 0.83 ± 0.1 dB during an irradiance cycle. The daily increase in IBP was a result of an increase in the number of cells during cultivation, while the diel variation was partly resulted from the variation of volume of cells by photosynthesis. In addition, cell division and separation might affect IBP. IBP of another dinoflagellate Amphidinium carterae Hulburt was also measured by a 10MHz transducer during a 3-day cultivation period while cell volume and photosynthetic capacity were measured four times a day (07:00, 12:00, 19:00, 24:00). This study suggests that high-frequency acoustics may be a meaningful tool to investigate the photosynthetic metabolism of a phytoplankton cell. [This work was supported by Defense Acquisition Program Administration and Agency for Defense Development under the contract UD130007DD.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4830545
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2013
    detail.hit.zdb_id: 1461063-2
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  • 5
    Online Resource
    Online Resource
    Low-salinity-induced surface sound channel in the western sea of Jeju Island during summer
    Acoustical Society of America (ASA) ; 2015
    In:  The Journal of the Acoustical Society of America Vol. 137, No. 3 ( 2015-03-01), p. 1576-1585
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 137, No. 3 ( 2015-03-01), p. 1576-1585
    Abstract: Surface salinity in the western sea of Jeju Island in Korea becomes low due to the inflow of the Chinese coastal waters during summer. One of the characteristics of low salinity water is the formation of a surface sound channel (SSC) due to the decrease in sound speed by salinity. However, a quantitative analysis between low salinity water and SSC has not been fully investigated yet. In this paper, a temperature-salinity (T-S) gradient diagram is introduced in order to assess SSC formation and its acoustic characteristics are also investigated through a case study of low salinity waters. Maximum angles of limiting rays were less than 4.6° and low frequency cutoffs were higher than 2.0 kHz for the SSCs formed in low salinity water. When the salinity gradients were large ( & gt;0.5 psu/m), a SSC was formed more efficiently than other cases whose salinity gradients were small. On the other hand, a SSC was not formed in spite of highly positive salinity gradients when the amount of temperature gradients was negatively high enough ( & lt;−0.5 °C/m). However, the acoustic energy transfer in the surface ducts was dependent on frequency and position of source.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4913812
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2015
    detail.hit.zdb_id: 1461063-2
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  • 6
    Online Resource
    Online Resource
    Mobility of dinoflagellates measured by high-frequency ultrasound
    Acoustical Society of America (ASA) ; 2015
    In:  Journal of the Acoustical Society of America Vol. 137, No. 4_Supplement ( 2015-04-01), p. 2197-2197
    Details
    In: Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 137, No. 4_Supplement ( 2015-04-01), p. 2197-2197
    Abstract: The importance of phytoplankton contributing more than 50% of the global amount of photosynthesis has been emphasized for a long time. Sometimes, the over-growth of phytoplankton causes the negative influence such as red-tide phenomenon on marine ecological environments. Therefore, the measurement of the mobility of phytoplankton is important. In this study, the mobility of the benthic dinoflagellate, Amphidinium carterae Hulburt (A. Carterae) incubated by f/2 medium was investigated using high-frequency ultrasound. Backscattering signal from A. Carterae was measured for 2 s in every 2 min by a 40-MHz ultrasound transducer, and the integrated backscattering power calculation was followed. The mobility of A. carterae in response to the light was illustrated by M-mode image of the echoed signals. The mobility of A. carterae was estimated to about 0.4 mm/s for the upward movement in response to light, while its sedimentation rate was measured to about 0.1 mm/s in a dark environment. This study suggests that mobility of benthic dinoflagellates responding to light can be measured by M-mode imaging of high-frequency ultrasound. (This research was a part of the project titled “Measurement of cells division and photosynthesis of phytoplankton using ultrasound”, funded by the Ministry of Oceans and Fisheries, Korean.)
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4919987
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2015
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  • 7
    Online Resource
    Online Resource
    The Mirror Generalization Process in Reading: Evidence from Korean Hangul
    Springer Science and Business Media LLC ; 2021
    In:  Journal of Psycholinguistic Research Vol. 50, No. 2 ( 2021-04), p. 447-458
    Details
    In: Journal of Psycholinguistic Research, Springer Science and Business Media LLC, Vol. 50, No. 2 ( 2021-04), p. 447-458
    Type of Medium: Online Resource
    ISSN: 0090-6905 , 1573-6555
    URL: Article
    DOI: 10.1007/s10936-020-09736-1
    RVK:
    EQ 1000
    RVK:
    EQ 2695
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2021
    detail.hit.zdb_id: 2017227-8
    SSG: 5,2
    SSG: 7,11
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  • 8
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    Online Resource
    A preliminary study of ultrasound blood imaging in the common carotid artery of stroke patients
    Acoustical Society of America (ASA) ; 2012
    In:  The Journal of the Acoustical Society of America Vol. 131, No. 4_Supplement ( 2012-04-01), p. 3362-3362
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 131, No. 4_Supplement ( 2012-04-01), p. 3362-3362
    Abstract: Blood echogenicity is changed by red blood cell aggregation due to hemodynamic and hematological factors depending on a person. A stroke is known as a cerebrovascular accident due to lack of the blood flow. Hence, an ultrasound blood imaging could be the preliminary diagnosis for the stroke patient. In this paper, ultrasound images were acquired from the common carotid artery of stroke patients and the control group by the ultrasound imaging system (Voluson e, GE Healthcare, USA). The numbers of subject were 6 stroke patients and 5 healthy people for the control group, and their ages were 67±17 and 68±3 years old, respectively. The average of blood echogenicity of the stroke patients (54±8) was lower than that of the control group (96±8). The amplitudes of the cycle variation of blood echogenicity were similar for both of the stroke patient (18±6) and the control group (23±6). The preliminary experimental results showed the statistical difference of blood echogenicity between the stroke patients and the control group, and the data would be continuously collected from more volunteers (~20 people for each group) and discuss the data in the conference. [Work supported by NRF-2011-0017984.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4708671
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2012
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  • 9
    Online Resource
    Online Resource
    Acoustic measurements of volume backscattering strength from red tide phytoplankton, Cochlodinium   polykrikoides
    Acoustical Society of America (ASA) ; 2006
    In:  The Journal of the Acoustical Society of America Vol. 120, No. 5_Supplement ( 2006-11-01), p. 3016-3016
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 120, No. 5_Supplement ( 2006-11-01), p. 3016-3016
    Abstract: This research is to measure the volume backscattering strength, Sv, of the Cochlodinium polykrikoides (the main species of red tide in Korea) in order to investigate the possibilities of early detection of red tide using high-frequency transducers (5, 10 MHz). First, the Sv from the cultured C. polykrikoides was measured with the population density in the laboratory. Next, ultrasonic transducers were attached to the side of a research vessel, and the Sv was measured over 9-km ship track near Yeosu in the Korean southern sea. Seawater at three stations was sampled, and the number of C. polykrikoides was counted to compare the theoretical Sv with the measured one. The results show that the measured Sv was in agreement with the theoretical one. The Sv when the light was on was measured to be higher than that when the light was off in the laboratory, probably due to the increase of size and density of C. polykrikoides during photosynthesis. In the field experiment, the Sv was measured in real time with the position information from the Global Positioning System data. This research proposes the use of underwater ultrasonic technology for early detection of red tide in real time.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4787070
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2006
    detail.hit.zdb_id: 1461063-2
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  • 10
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    Online Resource
    Probability distribution variation in high-frequency ultrasound blood echogenicity under in-vitro and in-vivo blood flow
    Acoustical Society of America (ASA) ; 2013
    In:  The Journal of the Acoustical Society of America Vol. 133, No. 5_Supplement ( 2013-05-01), p. 3541-3541
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 133, No. 5_Supplement ( 2013-05-01), p. 3541-3541
    Abstract: The dynamic phenomena of erythrocyte aggregation (EA) need to be analyzed statistically since EA varies spatially and temporally. In the present study, the cross-sectional B-mode images were acquired from a mock circulatory system with varying blood flow velocity under steady flow, and the human radial artery using an ultrasound biomicroscopy system at 20 MHz. The kurtosis (K) and skewness (S) coefficients, and the Nakagami parameter (m) were computed for each image. For the in-vitro experiment, both K and S increased about 0.87±0.18 and 0.63±0.09, respectively; while m decreased about 0.90±0.20 with increasing blood velocity from 12 to 44 cm/s. In-vivo experimental results also showed that K, S, and m varied during a cycle. When the blood velocity varied from 5 to 15 cm/s during a cardiac cycle, K and S increased about 1.42±0.64 and 0.44±0.11, respectively; while m decreased about 0.97±0.26. The in-vivo results seemed to be consistent with the in-vitro results in the sense that K and S increased with blood velocity while m decreased with velocity. This study suggests that the statistical analysis of blood echogenicity can be useful for in-vivo hemorheology and blood characterization. [Work supported by NRF-2012-0005005 and NIPA-2012-H0401-12-2006.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4806405
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2013
    detail.hit.zdb_id: 1461063-2
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