• Analytical Science and Technology
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• v.11 no.4
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• pp.271-280
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• 1998

Rice flour reference materials were prepared from the unpolished rice grown in Korea and certified for elemental composition. The reference materials consist of two samples containing normal and high level. The reference material at elevated level was prepared by spiking to the normal rice flour six toxic elements of As, Cd, Cu, Cr, Hg, Pb with $1.0{\mu}g/g$ on a dry weight basis. Homogeneity of the prepared materials was evaluated through the determination of Ca, Cu, Fe, Mn, Zn by instrumental neutron activation analysis (INAA) and atomic absorption spectrometry (AAS). Small variance of elemental composition among interbottled samples assured homogeneity of the prepared materials. The materials were decomposed by high pressure digestion and microwave digestion method. INAA, AAS, inductively coupled plasma-atomic absorption spectrometry (ICP-AES), ICP-mass spectrometry (MS) and vapour generation techniques were employed to analyze the reference materials. From this independent analytical results, the certified or reference values are determined for As, Ca, Cd, Cr, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, P, Pb, Se, Zn.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.32 no.2
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• pp.101-123
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• 2021

This study analyses the questions and answers contained in the Knowledge Information Database of the collaborative digital reference service, 'Ask a librarian'. And based on the results of status of user requests, this study draws information usage behavior in the early stages of the service was derived. 1,124 Knowledge Information Database items out of 3,506 cases was analyzed by nine criterion. ① Number of questions and whether to be reference questions, ② Subject and keywords of the question, ③ Purpose of the question, ④ Type of question, ⑤ User's information request, ⑥ Information source and reference services provided by the librarian, ⑦ Number of days to answer, ⑧ Level of the participating library, ⑨ Question type by topic. As a results of analysis, first, users asked for reference questions from various topics as needed, rather than one from a similar topic at a time, but more than half of the total pure reference questions were from the field of library information science. Second, about 71.35% of users were using the 'Ask a librarian' service to recommend a list of information resources related to a particular topic or research problem, and there were also questions that required consultation on the reading situation. Third, the most preferred sources of information for users were bibliography, and in the case of online information sources, users did not relatively prefer them. Fourth, the number of days required to answer was able to confirm significant differences depending on the type of question and the level of the participating library. Fifth, 31.33% of the purpose of the general field question showed that were self-generated.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1964-1980
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• 2016

This paper presents a new simplified harmonics extraction algorithm based on the synchronous reference frame (SRF) for an indirect current controlled (ICC) three-level neutral point diode clamped (NPC) inverter-based shunt active power filter (SAPF). The shunt APF is widely accepted as one of the most effective current harmonics mitigation tools due to its superior adaptability in dynamic state conditions. In its controller, the SRF algorithm which is derived based on the direct-quadrature (DQ) theory has played a significant role as a harmonics extraction algorithm due to its simple implementation features. However, it suffers from significant delays due to its dependency on a numerical filter and unnecessary computation workloads. Moreover, the algorithm is mostly implemented for the direct current controlled (DCC) based SAPF which operates based on a non-sinusoidal reference current. This degrades the mitigation performances since the DCC based operation does not possess exact information on the actual source current which suffers from switching ripples problems. Therefore, three major improvements are introduced which include the development of a mathematical based fundamental component identifier to replace the numerical filter, the removal of redundant features, and the generation of a sinusoidal reference current. The proposed algorithm is developed and evaluated in MATLAB / Simulink. A laboratory prototype utilizing a TMS320F28335 digital signal processor (DSP) is also implemented to validate effectiveness of the proposed algorithm. Both simulation and experimental results are presented. They show significant improvements in terms of total harmonic distortion (THD) and dynamic response when compared to a conventional SRF algorithm.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.90-94
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• 2007

The conventional single-reference station positioning is affected by systematic errors such as ionospheric and tropospheric delay, so that the rover must be located within 10 km from the reference station in order to acquire centimeter-level accuracy. The medium-range real-time kinematic has been proven feasible and can be used for high precision applications. However, the longer of the baseline, the more of the time for resolving the integral ambiguity is required. This is due to the fact that systematic errors can not be eliminated effectively by double-differencing. Recently, network approaches have been proposed to overcome the limitation of the single-reference station positioning. The real-time systematic error modeling can be achieved with the use of GPS network. For expanding the effective range and decreasing the density of the reference stations, Land Survey Bureau, Ministry of the Interior in Taiwan set up a national GPS network. In order to obtain the high precision positioning and provide the multi-goals services, a GPS network including 66 stations already been constructed in Taiwan. The users can download the corrections from the data center via the wireless internet and obtain the centimeter-level accuracy positioning. The service is very useful for surveyors and the high precision coordinates can be obtained real time.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.402-408
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• 2021

GNSS-Reflectometry (GNSS-R) is a technique for measuring and analyzing signals transmitted from satellites, reflecting on the surface of land or sea. GNSS-R is mainly used for measuring the water level variation, typhoon and meteorological anomaly, soil moisture, and snow depth. This paper describes the concept and measurement principle of GNSS-R technology, especially focusing on the field of marine utilization and its feasibility. In particular, it presents the applications of this technique for monitoring the safety of marine environment as well as the marine vessel and their utilization areas based on currently available infrastructure on the ground and maritime reference stations, such as the existing differential GNSS reference stations and integrity monitors (DGNSS RSIM), and GNSS reference station infrastructure, using the ground-based and the satellite-based GNSS-R approaches.

• Biomedical Science Letters
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• v.16 no.1
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• pp.19-24
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• 2010

We analyzed and compared the concentration of total cholesterol (CHOL), high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol and triglyceride (TG) in serum and the serum protein electrophoresis fractions of thyroid disease patients. In comparison with the average of reference, our data showed that the average concentration of CHOL, LDL cholesterol and TG in hyperthyroidism patients were decreased significantly, but HDL cholesterol was increased significantly. In hypothyroidism patients, CHOL, HDL cholesterol, LDL cholesterol and TG were all increased significantly. In comparison of the concentration of lipids in each patient to reference range, 28.3% of hyperthyroidism patients showed abnormally low level of total cholesterol. In the patients with hypothyroidism, the percentage of patients showed abnormally high level of CHOL, HDL cholesterol, LDL cholesterol and TG were 37.7%, 10%, 68.8% and 49.1%, respectively. In our studies of serum protein electrophoresis, the average of ${\alpha}_2$-globulin and $\gamma$-globulin in hyperthyroidism patients were increased and $\beta$-globulin was decreased significantly. In hypothyroidism patients, the average of $\gamma$-globulin was increased and $\beta$-globulin was decreased significantly. In comparison of protein fractions of each patient to reference range, 38.3% and 50.0% of hyperthyroidism patients showed abnormally high levels of ${\alpha}_2$-globulin and $\gamma$-globulin, but 73.3% of patients showed abnormally low level of $\beta$-globulin. In hypothyroidism patients, 70.4% of patients were abnormally decreased in $\beta$-globulin and 63.9% of patients were abnormally increased in $\gamma$-globulin. These data suggest that the concentrations of CHOL, HDL cholesterol, LDL cholesterol and TG are not critical data for clinical interpretation of hyperthyroidism, but the levels of them are useful for interpretation of hypothyroidism patients. Our results of serum protein electrophoresis suggest that the concentration of serum protein electrophoresis fractions can be useful to understand the thyroid disease.

• Journal of Information Management
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• v.42 no.2
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• pp.85-102
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• 2011

Conventionally, scientific data visualization is thought of as one of activities performed by scientists during the scientific data analysis. However, recently, there exits a set of research papers which count scientific data visualization as a independent research area. They show the research subjects for studying the scientific data visualization technology and methods. In case, a scientist or group of scientists can not solve their own visualization problem due to the unskillfulness and inexperience on using visualization tool. Therefore, it needs to help them by the systematic way for solving the problem. In this study, we analyze and propose the national level scientific visualization support system for scientists. In particular, we first analyze the existing papers and find out the critical success factors. Then, by integrating the findings of the analysis, we propose the research areas which need to be focused, and the strategic direction and specific research topics for scientific data visualization support system in national level.

• The Journal of the Acoustical Society of Korea
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• v.22 no.6
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• pp.463-471
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• 2003

The results of the APMP (Asia Pacific Metrology Programme) regional intercomparison of acoustic calibrators were reviewed and analyzed. The artefacts used in intercomparison are a sound level calibrator and a pistonphone. The microphones used to measure the output pressure level are 1" and 1/2" standard microphones (LS1P, LS2P) as well as 1" and 1/2" reference microphones (WS1P/F, WS2P/F). The results obtained using standard microphones are satisfactory, but those obtained by the reference microphones, even though E/sub n/ values are within ±1.0, showed great deviations. Such results had come from the inaccurate calibration of reference microphones. By using the correct calibration results which were obtained by the recently established international standards, the new results were very similar to those of the foreign standard institutes.

• Agribusiness and Information Management
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• v.10 no.1
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• pp.1-15
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• 2018

Many paddy cultivating farmers in the country are forced to use their limited resources to produce adequate food for their family, leading to the degradation and reduction in potential of these resources. The yield levels of paddy at the farmers' level and in the Front Line Demonstrations (FLDs) conducted in the farmers' fields is not at par with potential yield of the paddy variety. The gap between potential yield of crop variety and yield realized in FLDs refers to Research gap and the yield gap between FLDs and due to farmers' practice refers to Extension gap. The earlier studies conducted in India in general and in Andhra Pradesh in particular highlighted the existence of both research and extension gaps with reference to paddy. It is essential that, the narrowing of both research and extension gaps is not static, but dynamic considering the influence of technological interventions in boosting paddy yields at FLDs level and at farmers' level and also with the improvement of the yield potential of paddy varieties. This calls for integrated and holistic approaches to address these two gaps and with this background, the researcher aimed at this in depth study. The findings revealed that, research gaps are high with reference to weed management and pest management and extension gaps are high with reference to farm mechanization followed by fertilizer management. Reliable source of seed, capital use and frequency of meetings with Scientists or Agricultural Officers significantly influence the extension gaps in paddy. Farmers also prioritized socio-economic and technical constraints and the analysis infers that, it is high time now for the farmers to adopt the planned technological interventions on scientific scale to minimize the extension gaps to the extent possible. As the enabling environment in the State of Andhra Pradesh is highly encouraging for the farmers with relevant policy instruments in the form of subsidized inputs, free power, credit at concessional rates of interest, constructing irrigation projects etc., the adoption of the proposed technological interventions significantly contribute to minimizing both research and extension gaps in paddy cultivation in Kurnool district of Andhra Pradesh.

• Journal of the Korean Society of Radiology
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• v.12 no.7
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• pp.807-812
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• 2018

In this study, we investigated the conditions used in setting the recommendation level of general radiography diagnostic reference and tried to evaluate the effective dose and biological evaluation using PCXMC v2.0 program. As a result based on the effective dose of male in ICRP 60, the highest Pelvis AP was 0.794 mSv. The lowest Chest PA was 0.050 mSv. In the case of ICRP 103, the highest T-Spine AP was 0.906 mSv The lowest Chest PA was 0.052 mSv. For 40 years old male and female adults, effective doses of general radiography were evaluated and even if the medical exposures are not subject to the limit of dose, efforts should be made to reduce the medical exposures of the people by keeping the dose below the recommended amount in order to minimize the probable effect of radiation hazard.