• Journal of Life Science
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• v.31 no.12
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• pp.1128-1141
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• 2021

'Angelica' is one of the most traditionally consumed medicinal herbs around Northeast Asia including Korea for treatments of various diseases or health care purposes like hematopoiesis, blood circulation for women, sedative, analgesic, and a tonic medicine etc. Angelica gigas Nakai, a Korean native species of Angelica, is clearly different from the others in containing a high concentration of active ingredients like pyranocoumarines including decursin, decursinol, and decursinol angelate. These compounds have various kinds of positive effects such as anti-tumor activity including the precaution of neutropenia occurred during anticancer drug administration, improvements of metabolic disorders, menstrual irregularity, impairment of renal function, respiration improvement, cognition-enhancement, anti-inflammatory effect, anti-oxidative effect, enhancing fertility and so forth. Thus it implies incredible potentialities in future development for foods and drugs. However, certain purity-related qualities and/or overdose in food products can cause side effects like toxicities; therefore, their safety profiles should also be considered. This review focuses on the positive and negative effects of three pyranocoumarines in Angelica gigas Nakai and some possibilities and considerations for future food and drug products development.

• Journal of the Korean Geotechnical Society
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• v.23 no.7
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• pp.5-16
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• 2007

The monitoring and investigation of underwater landslide help to understand its mechanism, increase the usefuless of design and construction and reduce the losses. This paper presents three high resolution geophysical techniques electrical resisitance, ultrasonic wave reflection imaging, and shear wave tomography conducted to determine the lab-scaled submerged landslide. Electrical resistance profiles of a soil mass obtained by an electrical resistance probe provide detailed information to assess the spatial distribution of the soil mass with milimetric resolution. An ultrasonic wave image obtained by recording the reflections from interfaces of different impedance materials permits detecting layers and landslide with submilimetric resolution. The pixel based image of immersed landslides is created by the inversion of the boundary information achieved from the traveling time of shear waves. The experimental results show that the ultrasonic wave imaging and the electrical resistance can provide complementary information; and their association with S-wave tomography image can produce a 3-D view of the underwater landslide. This study suggests that geophysical techniques may be effective tools for the detection of the underwater landslides and spatial distribution offshore.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.10
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• pp.734-745
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• 2006

This paper presents a PC cluster-based distributed VOD server that minimizes the load of an interconnection network by adopting the VIA communication protocol and the interval cache algorithm. Video data is distributed to the disks of the distributed VOD server and each server node receives the data through the interconnection network and sends it to clients. The load of the interconnection network increases because of the large amount of video data transferred. This paper developed a distributed VOD file system, which is based on VIA, to minimize cost using interconnection network when accessing remote disks. VIA is a user-level communication protocol removing the overhead of TCP/IP. This papers also improved the performance of the interconnection network by expanding the maximum transfer size of VIA. In addition, the interval cache reduces traffic on the interconnection network by caching, in main memory, the video data transferred from disks of remote server nodes. Experiments using the distributed VOD server of this paper showed a maximum performance improvement of 21.3% compared with a distributed VOD server without VIA and the interval cache, when used with a four-node PC cluster.

• Korean Journal of School Psychology
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• v.18 no.3
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• pp.317-349
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• 2021

This study was conducted to examine the reliability and validity of the internet (IOS-Q), Game (GOS-Q), and Smartphone (SOS-Q) Overuse Screening Questionnaires in a large community sample of adolescents. To achieve this goal, data from 9,336 middle school students (male: 4,796, female: 4,540) was divided into two groups and analyzed by conducting confirmatory factor analysis and exploratory factor analysis, respectively. We conducted another confirmatory factor analysis on a separate sample of data from 4,536 elementary school students (male: 2,260 male, female: 2,276) and 6,551 middle school students (male: 3,013, female: 3,538) from other populations. As a result of factor analysis, IOS-Q was consisted of 17 items, GOS-Q was consisted of 19 items, and SOS-Q was consisted of 18 items. The IOS-Q and GOS-Q factors were psychological dependence, failure to control use despite recognizing problems, dangerous use, and reduced interest in other areas while the SOS-Q factors were dangerous and obsessive use, failure to control use despite recognizing problems, reduced interest in other areas, and withdrawal/tolerance. Each factor reflected the major facets of behavioral addiction or impulse control disorder, and the questionnaires had good internal consistencies of .880-.915. Latent profile and ROC analyses were conducted to determine cutoff points for screening high-risk groups. Lastly, theoretical and practical implications as well as the limitations of this study were discussed.

• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.127-137
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• 2021

Air emission charge for nitrogen oxide as a precursor of fine dust has been introduced and implemented within the country from 2020. Therefore, the development of economical combustion technology for NOx reduction has got more needed urgently. This study investigated the air-staging effect as a way to reduce the NOx during combustion of domestic unused forest biomass, recently possible to secure REC (Renewable Energy Certification) as a substitute for overseas wood pellets in a 0.1 MWth circulating fluidized bed combustion test-rig. Operating conditions were comparison with and without air-staging, the supply position of tertiary air (6.4 m, 8.1 m, 9.4 m in the combustor) and variation of air-staging ratio (Primary air:Secondary air:Tertiary air=91%:9%:0%, 82%:9%:9%, 73%:9%:18%). NO and CO concentrations in flue gas, profiles of temperature and pressure at the height of the combustion, unburned carbon in sampled fly ash and combustion efficiency on operating conditions were evaluated. As notable results, NO concentration with air-staging application under tertiary air supply at 9.4 m in the combustor reduced 100.7 ppm compared to 148.8 ppm without air-staging while, CO concentration increased from 52.2 ppm without air-staging to 99.8 ppm with air-staging. However, among air-staging runs, when tertiary air supply amount at 6.4 m in the combustor increased by air-staging ratio (Primary air:Secondary air:Tertiary air=73%:9%:18%), NO and CO concentrations decreased the lowest 90.8 ppm and 66.1 ppm, respectively. Furthermore, combustion efficiency at this condition was improved to 99.3%, higher than that (98.3%) of run without air-staging.

• Journal of Life Science
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• v.24 no.12
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• pp.1371-1377
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• 2014

Superoxide dismutase is a family of important antioxidant metalloenzymes and catalyzes the dismutation of toxic superoxide anions into dioxygen and hydrogen peroxide. A recent study identified the partial superoxide dismutase (SOD) gene in olive flounder (Paralichthys olivaceus). The same study reported that it strongly induced benzo[a]pyrene and that it was an indicator of aquatic oxidative stress responses. However, its transcriptional response against viral infection has not been investigated. In the present study, the spatial and temporal expression profiles were analyzed to investigate the function of Of-SOD in the antiviral response. The Of-SOD transcripts were ubiquitously detected at various levels in diverse tissues in a real-time PCR. The expression of Of-SOD was significantly higher in the muscles, liver, and brain but extremely low in the stomach and spleen. Following a VHSV challenge, the expression of Of-SOD increased within 3 h in the kidneys and decreased to the original level 2 days postchallenge. In muscle, liver, and brain, Of-SOD mRNA was similarly up-regulated at 3-6 h postchallenge and then decreased to the basal level. Although the expression pattern and induction time differed slightly depending on the tissue, the transcript of Of-SOD consistently increased in the acute infection response, but the expression was low in the chronic response. The expression of Of-SOD was induced after the VHSV infection, and Of-SOD was probably involved in the immune response against the viral challenge. These results suggest that SOD may play important roles in the immune defense system of P. olivaceus and perhaps contribute to the protective effects against oxidative stress in olive flounder.

• Progress in Medical Physics
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• v.9 no.2
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• pp.77-88
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• 1998

Wedge shaped isodoses are desired in a number of clinical situations. Hard wedge filters have provided nominal angled isodoses with dosimetric consequences of beam hardening, increased peripheral dosing, nonidealized gradients at deep depths along with the practical consequendes of filter handling and placement problems. Dynamic wedging uses a combination of a moving collimator and changing monitor dose to achieve angled isodoses. The segmented treatment tables(STT) that monitor unit setting by every distance of moving collimator, was induced by numerical formular. The characteristics of dynamic wedge by STT compared with real dosimetry. Methods and Materials : The accelerator CLINAC 2100C/D at Yonsei Cancer Center has two photon energies (6MV and 10MV), currently with dynamic wedge angles of 15$^{\circ}$, 30$^{\circ}$, 45$^{\circ}$ and 60$^{\circ}$. The segmented treatment tables(STT) that drive the collimator in concert with a changing monitor unit are unique for field sizes ranging from 4.0cm to 20.0cm in 0.5cm steps. Transmission wedge factors were measured for each STT with an standard ion chamber. Isodose profiles, isodose curves, percentage depth dose for dynamic wedge filters were measured with film dosimetry. Dynamic wedge angle by STT was well coincident with film dosimetry. Percent depth doses were found to be closer to open field but more shallow than hard wedge filter. The wedge transmission factor were decreased by increased the wedge angle and more higher than hard wedge filters. Dynamic wedging probided more consistent gradients across the field compared with hard wedge filters. Dynamic wedging has practical and dosimetric advantages over hard filters for rapid setup and keeping from table collisions. Dynamic wedge filters are positive replacement for hard filters and introduction of dynamic conformal radiotherapy and intensity modulation radiotherapy in a future.

• Progress in Medical Physics
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• v.25 no.4
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• pp.271-280
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• 2014

Recently, digital breast tomosynthesis (DBT) has been investigated to overcome the limitation of conventional mammography for overlapping anatomical structures and high patient dose with cone-beam computed tomography (CBCT). However incomplete sampling due to limited angle leads to interference on the neighboring slices. Many studies have investigated to reduce artifacts such as interference. Moreover, appropriate filters for tomosynthesis have been researched to solve artifacts resulted from incomplete sampling. The primary purpose of this study is finding appropriate filter scheme with FBP reconstruction for DBT system to reduce artifacts. In this study, we investigated characteristics of various filter schemes with simulation and prototype digital breast tomosynthesis under same acquisition parameters and conditions. We evaluated artifacts and noise with profiles and COV (coefficinet of variation) to study characteristic of filter. As a result, the noise with parameter 0.25 of Spectral filter reduced by 10% in comparison to that with only Ramp-lak filter. Because unbalance of information reduced with decreasing B of Slice thickness filter, artifacts caused by incomplete sampling reduced. In conclusion, we confirmed basic characteristics of filter operations and improvement of image quality by appropriate filter scheme. The results of this study can be utilized as base in research and development of DBT system by providing information that is about noise and artifacts depend on various filter schemes.

• Journal of the Korean earth science society
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• v.41 no.5
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• pp.459-468
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• 2020

In this study, the selection criteria for the occurrence of sea breezes in the Boseong area during the spring season (March-May) of 2016-2017 were prepared for the analysis of vertical weather characteristics. For this purpose, wind speed values were determined using the measured precipitation, cloud volume, wind direction, the difference between the ground and sea temperature, a wind Profiler at an altitude of 1 km, and numerical model data. The dates of the sea breezes in Boseong were classified according to the selection criteria, and the spatial and temporal characteristics of the sea breezes were identified by analyzing the time and altitude of the sea breeze and the size of the wind speed. Sea breezes occurred 23 out of 183 days (12%), and in Boseong, at least 1.2 out of 10 spring days exhibited sea breezes. Sea winds ranged from 1200 to 1800 LST, mainly from ground to 700 m altitude during the day. In addition, the maximum wind speed averaged 4.9 m s^-1, at an altitude of 40 m at 1600 LST, showing relatively lower values than those in a preceding study. This seems to be owing to the reduction in wind speed due to the complexity of the coastal terrain.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.38 no.2
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• pp.33-41
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• 2001

Currently, the compression is one of the most important technology in multimedia society. Audio files arc rapidly propagated throughout internet Among them, the most famous one is MP-3(MPEC-1 Laver3) which can obtain CD tone from 128Kbps, but tone quality is abruptly down below 64Kbps. MPEC-II AAC(Advanccd Audio Coding) is not compatible with MPEG 1, but it has high compression of 1.4 times than MP 3, has max. 7.1 and 96KHz sampling rate. In this paper, we propose an algorithm that decreased the capacity of AAC encoding computation but increased the processing speed by optimizing psychoacoustic model which has enormous amount of computation in MPEG 2 AAC encoder. The optimized psychoacoustic model algorithm was implemented by C++ language. The experiment shows that the psychoacoustic model carries out FFT(Fast Fourier Transform) computation of 3048 point with 44.1 KHz sampling rate for SMR(Signal to Masking Ratio), and each entropy value is inputted to the subband filters for the control of encoder block. The proposed psychoacoustic model is operated with high speed because of optimization of unpredictable value. Also, when we transform unpredictable value into a tonality index, the speed of operation process is increased by a tonality index optimized in high frequency range.