• Journal of Korean Society for Atmospheric Environment
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• v.34 no.2
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• pp.269-280
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• 2018

This paper reports the results of field evaluation to determine the levels of heavy metals in major industrial complexes in Korea over a seven year period (2007~2013). The measurement of heavy metal was conducted using quartz fiber filter sampling and ICP-AES analysis. In order to validate the analytical performance of these methods, studies were also carried out to investigate data quality control(QC) parameters, such as the method detection limit (MDL), repeatability, and recovery efficiencies. The average concentrations of total suspended particulates (TSP) for the nine industrial complexes in Korea were $104{\sim}169{\mu}g/m^3$, which was higher than other industrial complexes and urban areas. The Sihwa and Banwol industrial complexes were shown to be the biggest contributing sources to high TSP emission ($159{\mu}g/m^3$ and $169{\mu}g/m^3$, respectively). The concentrations of heavy metals in TSP were higher in the order of Fe>Cu>Zn, Pb, Mn>Cr, Ni, As and Cd. It was observed that Fe was the highest in the Gwangyang and Pohang steel industrial complexes. The concentrations of Zn and Pb were high in Onsan, Sihwa and Banwol industrial complexes, and this was attributed to the emission from the nonferrous industry. Additionally, Cr and Ni concentrations were high in the Sihwa and Banwol industrial complexes due to plating industry. On the other hand, Ulsan and Onsan industrial complexes showed high Cr and Ni concentrations as a response to the emission of metal industry related to automobile. The correlation analysis revealed the high correlation between Cr and Ni in plating industry from Sihwa and Banwol industrial complexes. Adding to this, components related to coal combustion and road dust showed high correlation in Pohang and Gwangyang industrial complexes. Then Onsan and Ulsan industrial complexes showed high correlation among components related to the nonferrous metals.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.12
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• pp.801-809
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• 2012

Long-term measurement of total mercury (TM) and dissolved gaseous mercury (DGM) were performed in Yangsuri marsh. Average TM and DGM concentrations were $2.0{\pm}2.0$ ng/L and $15.0{\pm}2.8$ pg/L, respectively, indicating that only 2.6% of TM existed as the form of DGM in Yangsuri marsh. While TM did not show the seasonal variation a statistically high DGM concentration was observed in warm season, indicating that DGM was effectively produced by strong solar radiation and high water temperature. There was no relationship between TM and DGM concentrations in Yangsuri marsh, as observed in other studies. DGM in Yangsuri marsh was supersaturated for most of sampling period; therefore, one can conclude that $Hg^0$ in water surface can readily volatilize to the atmosphere.

• The Journal of the Korea Contents Association
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• v.18 no.5
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• pp.432-445
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• 2018

For health care professionals(HCPs) who have relatively higher possibility of exposing tuberculosis(Tb), it is important for them to equip with proper levels of knowledge and prevention activities. In terms of establishment of Tb education model for junior HCPs, therefore, literature review was done alongside 129 junior HCPs and 14 HCPs were asked to answer questionnaires and telephone survey. The results are follows.; Firstly, six educational themes such as epidermiology of Tb, Tb transmission and patho-physiology, test and diagnosis, latent Tb, Tb treatment, and Tb prevention were identified, based on the literature review. Secondly, the junior HCPs showed lower levels of knowledge regarding epidermiology, transmission and patho-physiology and latent Tb, compared to the other themes. When education courses are planned, longer period of time should be given to the lower level of knowledge areas. Thirdly, the HCPs emphasized that definition and type of Tb should be well integrated into the education in particular epidermiology education. They also responded that hospital infection and infection cycle of Tb need to be addressed during educational session about transmission and patho-physiology. in addition, they said that specific and detailed contents about diagnosis and group examination should be carefully delivered during the education, along with diagnosis, test and application of personal protective devices during education of latent Tb. They also answered that patient education and adverse effect of Tb medication should be taught during Tb treatment session, as well as self activities of health promotion for junior HCPs and systematic TB education as key way of Tb prevention. As the findings were from limited numbers of respondents and contained the sampling bias, the result has to be carefully interpretated prior to generalization. Therefore, further survey with larger study population is required in terms of development of Tb education model.

• Journal of Wetlands Research
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• v.9 no.1
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• pp.107-114
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• 2007

This study aimed to investigate the hexachlorobenzene (HCB) dechlorinating ability of sediment microbes collected from a natural canal receiving secondary effluents from an industrial estate and nearby factories. Nine sites along the stream and one in the estuary in the Gulf of Thailand into which the canal spills were specified and sampling for sediment and water. Preliminary analysis of the sediments showed that the first four sites nearest to the discharging location were contaminated by HCB within the range of 0.18 to 1.25 ppm. Apart from that, 1,3,5-trichlorobenzene which has never been commercially produced or used in any manufacturing processes except for the transformation from higher chlorinated benzene was also identified in the range of 0.16 to 0.24 ppm. This suggested a possibility of sporadically HCB contamination in this stream. Of more important, people in the community along this canal earn their living by coastal fishery; hence, posing a risk of spreading HCB and its less chlorinated congeners via food chain from caught marine creatures to human. As a result, there is an urgent need to understand the behavior of HCB dechlorination in this stream sediment which can lead to a clean-up action in the future. Serum bottles with sediment slurries (sediment to water ratio of 1:1 (v/v) and filtered to remove particles larger than 0.7 mm) from each site were inoculated with 2 mg/l of HCB, kept anaerobically in the dark at room temperature without any nourishment, and analyzed for HCB and its less-chlorinated congeners every 6 days. Total chemical oxygen demand, suspended solids, and volatile suspended solids were in the range of 21,492-73,584, 158,100-518,100 and 6,000-32,700 mg/l, respectively. It was found that all sediment slurries began to dechlorinate HCB in 12 to 30 days and the HCB was completely removed within 42 to 60 days or so. On the other hand, there was no HCB dechlorination occurred in the controlled set which was sterilized by autoclaving prior to the addition of HCB. This implies that the HCB transformation was solely due to microorganisms' activities. HCB was dechlorinated principally via pentachlolobenzene to 1,2,3,5-tetrachlorobenzene and terminated at 1,3,5-trichlorobenzene which is the major pathway as reported by many researchers. Dichlorobenzene has not been detected in any samples within the dechlorination period of 60 days. The results indicate that the microbial matrix in the sediment of this stream has an outstanding capability to dechlorinate HCB. Existing substrates and nutrients which mainly sorbed onto the solid phase and the typical temperature in Thailand were sufficient and suitable to promote the activities of these HCB-dechlorinating microbes.

• The Journal of the Acoustical Society of Korea
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• v.14 no.2
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• pp.50-61
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• 1995

A time scale modification method yielding rate-modified speech while conserving the characteristic of speech was implemented in real-time using a goneral purpose digital signal processor. Time scale modification changed pronunciation speed only, producing a time difference between the input signal and the modified signal, making it impossible to implement it in real-time. In this thesis, a system was implemented to remove the time difference between the input and modified signals. Speech signals slowed down or speeded up by a physical time scale modification method, such as adjusting the motor speed of the cassett tape recorder, was used as the input signal. Physical modification that controled only the inter speed of the cassette tape player distorted the pitch period of the original speech. In this study, a real-time system was implemented so that the pitch-distorted speech was reconstructed back to the original by fractional sampling pitch shifting using an FIR filter, and this signal was time scale modified to match the cassette tape recorder motor speed using SOLA time-scale medification. In experiments using speech signals medifiedby the proposed method, results obtained using a 16-bit resolution ADSP2101 processor and using computer simulations employing floating point operations showed about the same average frame signal-to-noise ratio of about 20 dB.

• Journal of Environmental Health Sciences
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• v.37 no.1
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• pp.29-43
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• 2011

The seasonal characteristics of atmospheric particulate matter (PM) were evaluated through the measurement of $PM_{10}$ (particles with an aerodynamic diameter of less than 10 ${\mu}m$) and $PM_{2.5}$ (particles with an aerodynamic diameter of less than 2.5 ${\mu}m$) collected in the downtown area of Iksan city over roughly two weeks in each season of 2004. During the sampling period, 54 samples of $PM_{10}$ and $PM_{2.5}$ were collected and then measured for mass concentrations of PM and its water-soluble inorganic ion species. The concentrations of $PM_{10}$ and $PM_{2.5}$ were highly variable on a daily time scale in all seasons, especially in fall. Annual concentrations of $PM_{10}$ and $PM_{2.5}$ were $54.7{\pm}21.6\;{\mu}g/m^3$ and $34.0{\pm}13.4\;{\mu}g/m^3$, respectively. The daily concentrations of the analyzed ions similarly showed a pronounced variation, although a difference between seasons existed. Among them, $SO_4^{2-}$, $NO_3^-$ and $NH_4^+$ were the most abundant ions in all seasons, contributing up to 32% of $PM_{10}$ and 39% of $PM_{2.5}$. The contribution of $SO_4^{2-}$ and $NO_3^-$ showed a seasonal variation, as $SO_4^{2-}$ was the highest during spring and summer and $NO_3^-$ was the highest during fall and winter. Non-seasalt $SO_4^{2-}$ and $NO_3^-$ were found to exist mainly as neutralized chemical components of $(NH_4)_2SO_4$ and $NH_4NO_3$ due to the high concentration of $NH_4^+$ in PM samples, which were a major form of airborne PM in all seasons. Seasonal characteristics of $PM_{10}$ and $PM_{2.5}$ in Iksan were described in relation to the temporal variations of daily concentration of PM and its inorganic ion species including inter-particle reactions.

• Journal of Environmental Health Sciences
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• v.33 no.5
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• pp.408-421
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• 2007

The concentration characteristics of atmospheric particle matters (PM) including $PM_{2.5},\;PM_{10}$, and TSP were evaluated through the measurement data of PM_{2.5}$ (fine particulate), PM_{10-2.5}$ (coarse particulate), and PM_{over-10}$ collected using a MCI (multi-nozzle cascade impactor) sampler of a three-stage filter pack in spring of 2006 in Iksan area. During the sampling period of 10-15 March and 24 days from 8 April to 2 May, 32 samples for PM of each size fractions were collected, and then measured for PM mass concentrations and water-soluble inorganic ion species. Average concentrations of $PM_{2.5},\;PM_{10}$, TSP were $57.9{\pm}44.1mg/m^3$, $96.6{\pm}89.1mg/m^3$, and $114.8{\pm}99.7mg/m^3$, respectively. Water-soluble inorganic ion fractions to PM mass were found to be 36.5%, 18.0%, and 11.1% for $PM_{2.5}$, $PM_{10-2.5}$ and $PM_{over-10}$, respectively. By showing the high concentrations of PM samples during Asian dust events, those three fractions of PM were distinguished between the samples of Asian dust event and the samples of no event. However, the increase of PM concentrations observed during Asian dust events showed a different pattern for some Asian dust events. The differences of those three fractions in the size distribution may depend on differences on place of occurrence of Asian dust storm and course of transport from China continent to Iksan area in Korea. However, the extent of PM mass contribution during Asian dust events was generally dominated by the coarse particles rather than the fine fraction of PM. The variations of water-soluble inorganic ion species concentration in those three PM fractions between the samples of Asian dust event and the samples of no event were also discussed in this study.

• Journal of Korean Public Health Nursing
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• v.3 no.1
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• pp.18-37
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• 1989

This study was done in order to analyze the factors which influenced the performance level of community health practitioners' task. Interview survey was done during the period from August to October, 1986. Interviewee were 166 CHPs among total of 217 CHPs in Kyonggi province area. Multiple stepwise regression and canonical correlation analysis were used to identify major factors influenced to perform community health practitioners' task. The results of this study were summarized as follows: 1. General characteristics of CHPs 1) Personal characteristics The average age of CHPs was 37.8 years and their marital status was $77.6\%$ of married, educational back-ground was $65.3\%$ of junior college graduation. Their job career was $38.6\%$ of between 1-3 years, $33.3\%$ of between 3-5 years, $22.2\%$ of less than 1 years. Most of CHPs$(62.8\%)$ were fully satisfied with their job, $33.3\%$ were moderately, and $3.8\%$ were not satisfied. 2) Working environmental condition Only $31.7%$ of CHPs were satisfied with their working condition of primary health post, $26.6\%$ were not satisfied. Half of CHPs$(52.5\%)$ replied having good cooperation with health center, $10.1\%$ replied bad. Cooperation with health subcenter was good in $32.9\%$, and bad in $21.9%$. Cooperation with private health institutions was good in $34.2\%$, bad in $21.6%$. 2. Performance level of community health practitioners' task Among a total of 52 contents of their functions medical history taking. physical examination, referral of diagnostic laboratory work-up($(86.4\%)$, health assessment of pregnant women$(82.1\%)$, development of health information system$(79.4\%)$, supervision of health workers $(78.4\%)$, follow-up of family planning acceptors$(77.3\%)$, and follow-up of family planning acceptors' side effects$(77.3\%)$ were actively performed. Diagnosis of pregnancy$(62.1\%)$, sampling of drinking water for quality test$(52.5\%)$, making list of equipment' & supplies $(51.5\%)$, evaluation of primary health post activities $(37.6\%)$, organization of village health workers$(32.4\%)$ and management of village health workers $(30.1\%)$ were poorly performed. 3. Stepwise multiple regression analysis of job function The factors which influenced the performance level of community health practitioners' function were age, marital status, educational level, job career, job satisfaction, satisfaction of working environment of primary health post, cooperation of health center, cooperation of health center, cooperation of private health instiutions in orders. These 9 variables were able to explain job function from $25.7\%$ of program planning to $6.7\%$ of management of common disease. 4. Canonical correlation analysis between the performance of function and general characteristics of CHPs. Cooperation of private health institutions was found to be the factor influencing task performance of community organization, management of primary health post, technical supervision of health personnels. Job satisfaction of CHPs was also found to be the factor influencing task performance of family planning, management of common disease and maintenance of health information system.

• The Korean Journal of Ecology
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• v.17 no.1
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• pp.79-90
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• 1994

Water samples were taken at 6 stations from the mouth of Keum River to Kogunsan Archipelago of West Sea during December, 1991 to August, 1992, to determine the distribution of heterotrophic bacteria, their biovolumes and heterotrophic activities. Heterotrophic marine bacteria ranged from $1.0\;{\times}\;10^3to\;5\;{\times}\;10^5c.f.u.$ /ml. As for morphological distribution measured by epifluorescence microscopy, rod-shaped bacteria were between 45% and 72% of all cells during investigation period. Average biovolume of sampled bacteria ranged from $(7.69\;{\pm}\;0.18)\;{\times}10^{-2}to\;(8.18\;{\pm}\;0.38)\;{\times}\;10^{-2}\;{\mu}m^3$ for coccoid bacteria, and from $(6.09\;{\pm}\;0.29)\;{\times}10^{-2}to\;(7.72\;{\pm}\;0.41)\;{\times}\;10^{-2}\;{\mu}m^3$ for rod-shaped ones. The activities of extracellular enzymes ranged from 0.01 to 2.6 ${\mu}M$ /l /hr for glucosidase, from 0.01 to 2.6 ${\mu}M$ /l /hr for amylase, from 0.01 to 8.86 ${\mu}M$ /I /hr phosphatase and from 0.01 to 0.94 ${\mu}M$ /l /hr for chitinase. Extracellular enzyme activities were higher in summer season than in other sampling periods, and phosphatase showed the highest activity among measured extracellular enzymes. Bacterial distribution and their extracellular enzyme activities were associated with water temperature and organic nutrients, but bacterial cell volumes showed no direct relationship with extracellular enzyme activities.

• Journal of KSNVE
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• v.8 no.5
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• pp.964-973
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• 1998

In this paper we propose a levitation and imbalance compensation controller design methodology of magnetic bearing system. In order to achieve levitation and elimination of unbalance vibartion in some operation speed we use the discrete-time Q-parameterization control. When rotor speed p = 0 there are no rotor unbalance, with frequency equals to the rotational speed. So in order to make levitatiom we choose the Q-parameterization controller free parameter Q such that the controller has poles on the unit circle at z = 1. However, when rotor speed p $\neq$ 0 there exist sinusoidal disturbance forces, with frequency equals to the rotational speed. So in order to achieve asymptotic rejection of these disturbance forces, the Q-parameterization controller free parameter Q is chosen such that the controller has poles on the unit circle at z = $exp^{ipTs}$ for a certain speed of rotation p ( $T_s$ is the sampling period). First, we introduce the experimental setup employed in this research. Second, we give a mathematical model for the magnetic bearing in difference equation form. Third, we explain the proposed discrete-time Q-parameterization controller design methodology. The controller free parameter Q is assumed to be a proper stable transfer function. Fourth, we show that the controller free parameter which satisfies the design objectives can be obtained by simply solving a set of linear equations rather than solving a complicated optimization problem. Finally, several simulation and experimental results are obtained to evaluate the proposed controller. The results obtained show the effectiveness of the proposed controller in eliminating the unbalance vibrations at the design speed of rotation.