• Journal of Korean Society of Water and Wastewater
• /
• v.27 no.6
• /
• pp.689-701
• /
• 2013

Bacterial growth and corresponding consumption of carbon and phosphorus were examined in which tap water samples containing a very low concentration of free chlorine were supplemented with organic carbon and/or phosphorus. The experiments were performed in a fed-batch mode under a controlled temperature of $20^{\circ}C$. In the phosphorus alone-added water, there was no significant increase in bacterial numbers measured as heterotrophic plate count (HPC) in the bulk water. However, bacterial growth was stimulated by the addition of carbon (e.g., bulk HPC levels increased to $10^3CFU/mL$) and further stimulated by the combined addition of carbon and phosphorus (e.g., bulk HPC to $10^5CFU/mL$). The same effects were observed in biofilm HPC and biomass formed on polyethylene (PE) slide surfaces. In the water where organic carbon and phosphorus were added together, the highest biofilm HPC and biomass (measured as extracellular polymeric substance components) densities were observed which were $7.6{\times}10^5CFU/cm^2$ and $5.3{\mu}g/cm^2$, respectively. In addition to the bacterial growth, additions of organic carbon and/or phosphorus resulted in different bacterial carbon-to-phosphorus (C/P) consumption ratios. Compared to a typical bacterial C/P consumption ratio of 100:1, a higher C/P ratio (590:1) occurred in the carbon alone-added water, while a lower ratio (40:1) in phosphorus alone-added water. Comparative value (80:1) of C/P ratio was also observed in the water where organic carbon and phosphorus were added together. At the given experimental conditions, bacterial growth was deemed to be more sensitive to microbially available organic carbon than phosphorus. The effect of phosphorus addition, which resulted in a lower C/P consumption ratio, seemed to be tightly associated with the presence of microbially available organic carbon. These results suggested that the control of extrinsic carbon influx seemed to be more important to minimize bacterial regrowth in drinking water system, since even low content of phosphorus naturally occurring in drinking water was enough to allow a bacterial growth.

• Korean Journal of Environmental Agriculture
• /
• v.22 no.2
• /
• pp.148-152
• /
• 2003

The phosphorus(P) adsorption capacities of various filter media were investigated in relation to the size and types of fitter media to screen the optimum condition. The objective of this study was to evaluate the constructed wetland longevity by improving P adsorption capacity. The maximum P adsorption capacities of filter media A($4{\sim}10\;mm$), B($2{\sim}4\;mm$) and C($0.1{\sim}2\;mm$) were 8, 10 and 22 mg/kg, respectively, showing those increased as the filter media size decreased. Among the experimental media, the optimum filter media size was $0.1{\sim}2\;mm$. When the filter Medium was supplemented with organic materials which were piled up and decayed in the constructed wetland, the P adsorption capacity was significantly enhanced Under the conditions of optimum fitter media size, the respective Maximum P adsorption capacities of filter media C when supplemented with Ca, Mg, Al and Fe were higher than that of filter media C. However the addition of Ca, Mg, Al and Fe to constructed wetland were not recommended because of the possibility of their secondary pollution. The maximum P adsorption capacity of filter media C was 22 mg/kg, but this was increased to 36 mg/kg when filter media C was supplemented with 2% oyster shell.

• Proceedings of the KAIS Fall Conference
• /
• 2011.05a
• /
• pp.161-164
• /
• 2011

본 논문에서는 MBR 공정 유출수의 화학응집에 따른 특성을 알아보고자 A2O공정 하수처리수를 대상으로 막의 공극 크기와 약품 교반시간 및 응집 침전시간에 따른 인 제거 효율을 조사하였다. 막 여과 전후의 시료에 대한 응집실험결과 막 여과 전후의 응집제 투입에 따른 인 제거효율은 막 여과 전 90%와 비교했을 때 각각 74.5, 71.2, 62.6%로 최고 37.4%까지 큰 차이를 보였으며 이것은 막 여과로 인하여 시료 내 존재하는 콜로이드성 물질들의 입자 크기가 작아져 응집반응을 위한 응집핵 형성에 영향을 주었기 때문이며 막의 공극 크기가 작을수록 인 제거 효율도 감소하는 것으로 나타났다. 완속교반과 침전시간을 길게 할수록 인 제거 효율이 증가하였다. 침전시간이 10분일 경우는 인 제거 효율이 막 여과 후의 시료에 대해서 각각 45.3, 35.1, 52.0%로 인 제거가 상당히 불안정하였고 60분일 경우에는 각각 83.4, 85.1, 80.7%로 탁월한 인 제거가 일어난 것을 알 수 있었다.

• The Journal of Korean Institute of Next Generation Computing
• /
• v.13 no.2
• /
• pp.18-25
• /
• 2017

In computer science, an encoding is a standardization of converting information to one format for audio, video or text. Therefore, the encoding information of the data should be known to open and read it and there are algorithms detecting encoder of the data. However, some informations of data could be disappeared by packet loss when transmitted on network, especially, if the data is snatched by packet sniffing or eavesdropping from wireless communications. In this paper, we improve the performance of encoding detection algorithm of 'uchardet' program for multi-byte encoded data with errors based on bit-shift algorithm. To simulate the performance, we generated Korean and Japanese text data with errors that is removed some random bits at random positions. Then the detection algorithm are tested using the data and 'uchardet-bitshift' showed better performance than 'uchardet'. When Korean texts are used, 'uchardet' could detect perfectly with ≤0.005% errors but it showed 0% detection rate with ≥1% errors while 'uchardet-bitshift' detected perfectly with ≤0.05% errors and it showed correct detection cases with ≥1% errors. Japanese texts with errors tend to report falsely as Chinese encoding because Japanese texts include lots of Chinese characters. As a results, we improved encoding detection algorithms by applying bit shift operation.

• 프린팅코리아
• /
• v.14 no.6
• /
• pp.59-60
• /
• 2014

인쇄잉크를 제조하는 사업체수와 종사자수는 증가추세를 보이고 있는 가운데, 10인 이상 사업체수와 종사자수는 2010년을 기점으로 하락하고 있는 것으로 나타났다. 10인 이상 사업체는 줄고 10인 이하 영세 사업체는 늘고 있는 것이다.

• Environmental engineer
• /
• s.61
• /
• pp.4-7
• /
• 1991

실내공기가 오염되었을 경우는 궁극적으로 환기를 강화시켜야함은 주지의 사실이다. 최근 미국의 ASHRAE에서는(1989년) 1인당 필요한 최소 외기량을 9$m^3$/hr/인에서 27$m^3$/hr/인까지 증가시키고, 흡연실과 금연실을 분리하지 않고 전체적으로 필요한 외기량을 설정하였다.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.38 no.3
• /
• pp.217-225
• /
• 2002

The authors examined the response of electrocardiogram(ECG) of Nile tilapia, Oreochromis niloticus [Linnaeus] to light stimuli. The experiments were performed in such a way that three levels of light stimuli(10, 100 and 400 lu$\chi$) were given to fishes with an electrode inserted into their bodies and then their ECGs were recorded continuously for 60 minutes in 16~18$^{\circ}C$. The results which are divided into by day and by night and then analyzed by fishes' conditions are as follows; 1. Nile tilapias reached a stable condition 3 minutes after anesthesia. In stable condition, the heart rate average was 47.6beat/min by day and 45.1beat/min by night. And the action potential average was 1.0.4$mutextrm{V}$ by day and 1.24$mutextrm{V}$ by night. 2. The heart rate average by three levels of light stimuli was, \circled1 In stimulus condition, in case of 10 lu$\chi$ 39.7beat/min by day and 38.2beat/min by night, in case of 100 lu $\chi$8.7beat/min by day and 36.9beat/min by night, and in case of 40.0. lux 36.8 beat/min by day and 35.8beat/min by night. \circled2 In recovery condition, in case of 10 lu$\chi$ 47.1beat/min by day and 46.0beat/min by night, in case of 100 lu$\chi$ 47.2beat/min by day and 45.6 beat/min by night, and in case of 400 lu$\chi$ 48.1beat/min by day and 46.6beat/min by night. 3. The action potential average by three levels of light stimuli was, \circled1 In stimulus condition, in case of 10 lu$\chi$ 1.22$mutextrm{V}$ by day and 0.71$mutextrm{V}$ by night, in case of 100 lu$\chi$ 0..63$mutextrm{V}$ by day and 0.90$mutextrm{V}$ by night, and in case of 400 lu$\chi$ 1.39$mutextrm{V}$ by day and 1.63$mutextrm{V}$ by night \circled2 In recovery condition, in case of 10 lu$\chi$ 1.26$mutextrm{V}$ by day and 1.59$mutextrm{V}$ by night, in case of 100 lu$\chi$ 2.63$mutextrm{V}$ by day and 3.65$mutextrm{V}$ by night, and in case of 400. lu$\chi$ 2.52$mutextrm{V}$ by day and 3.67$mutextrm{V}$ by night.

• 프린팅코리아
• /
• v.9 no.2
• /
• pp.46-49
• /
• 2010

통계청이 최근 발표한 '2008넌 기준 사업체기초통계조사 보고서(9차 개정)'에 따르면 1인 이상 전국 인쇄업 및 인쇄관련 산업의 총 인쇄물 생산액은 2007년(8조8306억8208만2천원) 대비 8.0% 증가한 9조5323억4728만8000원으로 집계됐다. 신문 특수인쇄물을 포함하면 15조원에 이를 것으로 추정된다. 한편 2008년 현재 등록된 1인 이상 총 인쇄업 및 인쇄관련 산업의 사업차는 1만 6709개 사로 2007년도의 1만7767개 사보다 5.9% 감소한 것으로 집계됐다. 종사자도 2007년도의 7만5231명보다 4.7% 감소한 7만1716명을 기록했다. 그리고 종사자 10인 이상 인쇄 및 인쇄관련산업 사업체 수는 1316개사로 종사자는 2만9849명이며 생산액은 3조9674억7900만원으로 집계됐다.

• Journal of Food Hygiene and Safety
• /
• v.26 no.3
• /
• pp.248-253
• /
• 2011

KFDA compiles the statistical data of food poisoning outbreaks two or more persons since 2002 in Korea and release them to the public on the web. There is a gap of outbreak number between the real situation and the reports. To reduce the gap, addition of sporadic individual case of food poisoning may be one of the solution method. The statistical data of Japan where food consumption pattern is similar to Korea, were used in this study to compare the ratio and the pattern between the outbreak cases two or more persons and individual cases. By doing so, the data of Japan regarding to outbreak cases two or more persons will be comparable to that of Korea. The data of 2002 and 2003 in Japan showed that sporadic individual cases were 43.3% in the total food poisoning cases. The individual cases occurred highly in unknown places (90-92.3%) and home (6.2-8.5%) whileas the outbreaks two or more persons occurred mostly in the place of restaurants (46.6-50.l%) and inns (9.2-9.8%). The food-borne pathogens attributed to the individual cases were C. jejuni (51.9%), Salmonella spp. (35.3%), and V. parahaemolyticus (9.8%) while those to the outbreak cases two or more persons were norovirus (31.3%), Salmonella spp. (20.8%), C. jejuni (15.5%) in Japan. The data of 2002-2009 between Korea and Japan showed the outbreak case report rate was 1:1.5 based on the total population number.

• Environmental engineer
• /
• s.90
• /
• pp.4-7
• /
• 1994