• Title/Summary/Keyword: Difference-in-difference Method

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Development of Adaptive Spatial Filter to Improve Noise Characteristics of PET Images (PET 영상의 잡음개선을 위한 적응적 공간 필터 개발)

  • Woo, S. K.;Choi, Y.;Im, K. C.;Song, T. Y.;Jung, J. H.;Lee, K. H.;Kim, S. E.;Choe, Y. S.;Park, C. C.;Kim, B. T.
    • Journal of Biomedical Engineering Research
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    • v.23 no.3
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    • pp.253-261
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    • 2002
  • A spatially adaptive falter was formulated to imrove PET image qualify and the Performance of the filter was evaluated using simulation and phantom and human PET studies. In the proposed filter. if a pixel was identified as the edge Pixel, the Pixel value was Preserved. Otherwise a Pixel was replaced by the mean of the pixel values weighted by 2:7: 2. A Pixel was identified as the edge Pixel. if it satisfies the following conditions : the number of ADs (absolute difference between center and neighborhood pixels) which is smaller than THl (($pix_max{\times}0.1/log_2(NPM)$, NPM : mean of 6 neighborhood pixels excluding minimum and maximum) is 8-k and the number of ADs which is lager than TH2 ($NPM{\times}0.1$) is k. where k : 2, 3, …, 6. The results of this study demonstrate the superior performance of the Proposed titter compared to Gaussian fitter, weight median filter and subset averaged median filter. The proposed tittering method is simple but effective in increasing uniformity and contrast with minimal degradation of spatial resolution of PET images and thus. is expected to Provide improved diagnositc quality PET images .

Effects of Conjugated Linoleic Acid-Triglyceride Additives on Quality Characteristics of Pressed Ham (Conjugated Linoleic Acid-Triglyceride 첨가가 프레스햄의 품질특성에 미치는 영향)

  • Lee, Jeong-Ill;Ha, Young-Joo;Lee, Jae-Ryung;Joo, Young-Kuk;Kwack, Suk-Joon;Do, Chang-Hee
    • Food Science of Animal Resources
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    • v.27 no.1
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    • pp.8-15
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    • 2007
  • Conjugated linoleic acid (CLA) was chemically synthesized using the alkaline isomerization method of com oil. CLA-TG was synthesized by reaction with sodium methoxide. Five different treatments were devised based on differences in the amount of CLA-TG added into the pressed han. for controls, 10% of pork back fat among the total component was only added without any CLA-TG. For the first treatment, 5% of CLA-TG among the lard component added into the press ham was replaced. For the 2nd, 3rd and 4th treatments, 10%, 15% and 20% of CLA-TG was respectively replaced. Pressed ham manufactured using CLA-TG was vacuum packaged and then stored for 1, 7, 14, 21 and 28 days at $4^{\circ}C$. Samples were analyzed for chemical composition, physico-chemical properties (pH, color), and texture characteristics. Typical chemical composition characteristics (moisture, crude protein, crude fat) were not significantly different between controls and CLA-TG treatment groups. Crude fat content of CLA-TG treatment groups was significantly lower than that of controls (p<0.05). pH values of controls was higher than that of CLA-TG treatment groups. The pH of control and CLA-TG treatment groups increased significantly as the storage period increased (p<0.05). Meat color (CIE $L^*,\;b^*$) of CLA-TG treatment groups was higher than that of controls. $a^*$ values were decreased by replacement of CLA-TG, but appeared to be unaffected by storage length. There was no significant difference in texture between controls and CLA-TG treatment groups. Based on these findings, we conclude that the physico-chemical properties and texture characteristics of manufactured pressed ham were not affected by CLA-TG addition. Also, our results indicate that high-quality pressed ham can be manufactured with CLA accumulation.

Comparison of Movement Distance and Home Range Size of Gold-spotted Pond Frog (Pelophylax chosenicus) between Rice Paddy and Ecological park - Focus on the Planning Alternative Habitat - (논과 생태공원에서 금개구리 이동 거리 및 서식영역 크기 비교 - 대체서식지 조성 중심으로 -)

  • Park, Su-Gon;Ra, Nam-Yong;Jang, Young-Soo;Woo, Seung Hyun;Koo, Kyo Soung;Chang, Min-Ho
    • Ecology and Resilient Infrastructure
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    • v.6 no.4
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    • pp.200-207
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    • 2019
  • The movement distance and home range size of Pelophylax chosenicus were identified in the rice paddy and ecological park as alternative habitats from July to November 2017. A total of 39 frogs were tracked by radio tracking method. As a result, the average move distance in the population of rice paddy was 11.7 ± 1.9 m (n = 64) and the population of ecological park was 24.7 ± 4.3 m (n = 39). The move distance between the two populations was significantly different. The mean MCP of the population of rice paddy was 181.2 ± 110.8 m2 (n = 11) and the population of ecological park was 416.1 ± 276.2 m2 (n = 10), but there was no significant difference. The population area of rice paddy was 4,160 m2 (Kernel density 95%) and the core area was 1,080 m2 (Kernel density 50%). The population area (Kernel density 95%) of ecological park was 5,391 m2 and the core area (Kernel density 50%) was 736 m2. This study shows that it is appropriate to construct the area of alternative habitat for P. chosenicus at least 1.33 ha, and it is more advantageous for the ecological park to be constructed than the paddy field with high development pressure and human interference. If the rice paddies were to be abandoned for several years, or to be used traditional farming methods, such as refraining from using agricultural machinery and chemicals, they could be used as alternative habitat for P. chosenicus.

Comparison Study of the Pulmonary Function and Serum Carboxyhemoglobin Level Between the Traffic Policmen and Clerk Policemen (교통경찰과 비 교통경찰의 폐기능과 혈중 Carboxyhemoglobin 수치에 대한 비교연구)

  • Kim, Sung Min;Cheon, Gyu Rak;Kim, Young Wook;Kim, Joon Hyung;Lee, Ho Hak;Hong, Soon Chang;Lee, Seung Hee;Park, Sang Joon;Chung, Joon Oh;Kim, Yun Kwon;Kim, So Yon;Kim, Young Jung;Cho, Min Koo;Lee, Gwon Jun;Lee, Kyung In
    • Tuberculosis and Respiratory Diseases
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    • v.55 no.6
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    • pp.560-569
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    • 2003
  • Background : A large number of pollutants such as sulfur dioxide, nitric oxide, carbon monoxide, particulate matter, and ozone influence on the body. These pollutants put a burden on the lung and the sequelae resulting from the oxidative stress are thought to contribute to the development of fibrotic lung disease, emphysema, chronic bronchitis and lung cancer. Also, carbon monoxide generated from the incomplete combustion of carbon-containing compounds is an important component of air pollution caused by traffic exhaust fumes and has the toxic effect of tissue hypoxia and produce various systemic and neurologic complications. The objective of this study is to compare the difference of pulmonary function and serum carboxyhemoglobin(CO-Hb) level between the traffic policemen and clerk policemen. Method : Three hundred and twenty-nine of traffic policemen, and one hundred and thirty clerk policemen were included between 2001 May and 2002 August. The policemen who took part in this study were asked to fill out a questionnaire which included questions on age, smoking, drinking, years of working, work-related symptoms and past medical history. The serum CO-Hb level was measured by using carboxyoximeter. Pulmonary function test was done by using automated spirometer. Additional tests, such as elecrocardiogram, urinalysis, chest radiography, blood chemistry, and CBC, were also done. Results : $FEV_1(%)$ was $97.1{\pm}0.85%$, and $105.7{\pm}1.21%$(p<0.05). FVC(%) was $94.6{\pm}0.67%$, and $102.1{\pm}1.09%$, respectively(p<0.05). Serum CO-Hb level was $2.4{\pm}0.06%$, and $1.8{\pm}0.08%$(p<0.05). After correction of confounding factors (age, smoking), significant variables were FVC(%), $FEV_1(%)$ and serum CO-Hb level(%)(p<0.05). Conclusion : Long exposure to air pollution may influence the pulmonary function and serum CO-Hb level. But, further prospective cohort study will be needed to elucidate detailed influences of specific pollutants on pulmonary function and serum carboxyhemoglobin level.

'Jangseong Pyunbaek Healing Forest(JPHF)' Visitors: Socio-demographic Characteristics, Use Patterns and Motivational Factors by Types of Visitors ('장성 편백치유의 숲' 방문객 유형에 따른 인구사회학적 특성, 이용행태 및 방문동기 요인)

  • Kim, Sang-Oh;Kim, Sang-Mi
    • Korean Journal of Environment and Ecology
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    • v.32 no.2
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    • pp.203-214
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    • 2018
  • This study was conducted to investigate the types, socio-demographic characteristics, use patterns, and visit motivations of visitors to "Jangseong Pyunbaek Healing Forest (JPHF)." Data were collected from 216 samples selected by convenient sampling method using questionnaire survey between October and November 2016. Data obtained from 476 respondents of the same type of survey during the same period were partly used to examine the types of activities of visitors to the study site. The results showed that 77.0 percent of respondents were categorized as "visitor for recreation" (VR: Those who visit JPHF for the purpose of general recreational experiences such as appreciating landscapes, tourism, social interactions rather than better health or healing). On the other hand, only 10.3 percent of respondents were "visitor for healing" (VH: Those who visit JPHF for the purpose of better health or physical and mental healing). VH showed a higher level of visit experiences to JPHF than VR and tended to expect JPHF as "the place to enjoy calm and natural experiences" more than VR did. VH tended to visit JPHF "alone" more, and their group size was also smaller than VR. About 26.8 percent of all respondents were not aware that JPHF was the "healing forest," and VH showed higher awareness of it than VR. About 66.8% of respondents assessed the managerial and operating states of JPHF positively while only 6.2% assessed them negatively. There was no difference in the assessment of managerial and operating states between VR and VH. The visitors of JPHF showed the markedly high use in main forest roads (use rate: 47.4%) and "Healing Field" (use rate: 59.2%) of JPHF. Regarding the visit motivations to JPHF, VH showed higher importance on "quietude," "health," and "tension release" than VR while VR rated higher importance on "social interaction." The paper discussed the managerial implications, findings, limitations and further studies.

Extraction Characteristics of Saponin and Acidic Polysaccharide Based on the Red Ginseng Particle Size (홍삼의 입자크기에 따른 사포닌 및 산성다당체의 추출 특성)

  • Cho, Chang-Won;Kim, Sang-Wook;Rho, Jeong-Hae;Rhee, Young-Kyung;Kim, Kyung-Tack
    • Journal of Ginseng Research
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    • v.32 no.3
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    • pp.179-186
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    • 2008
  • Effect of pulverization on total solid, crude saponin, and acidic polysaccharide contents of dried red ginseng main root were tested. Several particle size samples, including red ginseng main root (non pulverized), $10{\sim}40$ mesh powder, $40{\sim}100$ mesh powder, and >100 mesh powder were used in the extraction. The sequential solvent extraction method (1st: 70% EtOH at $70^{\circ}C$ for 12 hr, 2nd: 70% EtOH at $70^{\circ}C$ for 12 hr, 3rd: water at $70^{\circ}C$ for 12 hr) was applied to extract the saponins and acidic polysaccharide. Extraction yield of total solid of pulverized red ginseng ($10{\sim}40$ mesh size) was increased to 20% compared with that of non-pulverized. Especially, the crude saponin content of pulverized red ginseng ($10{\sim}40$ mesh size) showed an increase of 47% over non-pulverized. No difference in the component ratio was observed by pulverization, when the individual ginsenosides were quantified by HPLC. Also, extraction yield of acidic polysaccharide of pulverized red ginseng ($10{\sim}40$ mesh size) was increased 57% compared with that of non-pulverized. The results suggested that pulverization might be useful for increasing the extraction yield of red ginseng components.

THE EFFECT OF C-FACTOR AND VOLUME ON MICROLEAKAGE OF COMPOSITE RESIN RESTORATIONS WITH ENAMEL MARGINS (법랑질 변연으로 이루어진 복합레진 수복물의 체적과 C-factor가 미세누출에 미치는 영향)

  • Koo, Bong-Joo;Shin, Dong-Hoon
    • Restorative Dentistry and Endodontics
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    • v.31 no.6
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    • pp.452-459
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    • 2006
  • Competition will usually develop between the opposing walls as the restorative resin shrinks during polymerization. Magnitude of this phenomenon may be depended upon cavity configuration and volume. The purpose of this sturdy was to evaluate the effect of cavity configuration and volume on microleakage of composite resin restoration that has margins on the enamel site only. The labial enamel of forty bovine teeth was ground using a model trimmer to expose a flat enamel surface. Four groups with cylindrical cavities were defined, according to volume and configuration factor(Depth x Diameter / C-factor) - Group I : 1.5 mm ${\times}$ 2.0 mm / 4.0, Group II : 1.5 mm ${\times}$ 6.0 mm / 2.0, Group III : 2.Omm ${\times}$ 1.72 mm / 5.62, Group IV : 2.0 mm ${\times}$ 5.23 mm / 2.54. After treating with fifth-generation one-bottle adhesive - BC Plus$^{TM}$ (Vericom, AnYang, Korea), cavities were bulk flted with microhybrid composite resin - Denfill$^{TM}$ (Vericom). Teeth were stored in distilled water for one day at room temperature and were finished and polished with Sof-Lex system. Specimens were thermocycled 500 times between 5$^{\circ}$C and 55$^{\circ}$C for 30 second at each temperature. Teeth were isolated with two layers of nail varnish except the restoration surface and 1 mm surrounding margins. Electrical conductivity (${\mu}$A) was recorded in distilled water by electrochemical method. Microleakage scores were compared and analyzed using two-way ANOVA at 95% level. The results were as follows: 1. Small cavity volume showed lower microleakage score than large one, however, there was no statistically significant difference. 2. There was no relationship between cavity configuration and microleakage. Factors of cavity configuration and volume did not affect on microleakage of resin restorations with enamel margins only.

Effect of Proteinase Activity on the Cheddar Cheese Quality (단백분해 효소 활성(蛋白分解 酵素 活性)이 Cheddar Cheese의 품질(品質)에 미치는 영향(影響))

  • Kim, Min-Bae
    • Journal of Dairy Science and Biotechnology
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    • v.14 no.2
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    • pp.157-164
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    • 1996
  • This study aimed increase the quality during ripening of Cheddar cheese made with proteinase-negative mutant of Streptococcus lactis KCTC 1913 selected by curing. The degradation of protein during cheese ripening were investigated by electrophoresis and chromatography. The results were summarized as follow ; 1. The number of lactic acid bacteria decreased with the ripening stage, and that of the control cheese decreased faster than that of the cheese made with mutant. 2. Polyacrylamide gel electrophoretic analysis of cheese caseins revealed no difference between the cheese made with mutant and the control cheese, but differences along with the ripening stage were evident. 3. On Sephadex G-25 column chromatography, the extracts of bitter components from the green cheese and 3 month ripended cheese were fractionated into 3 fractions. With the progress of ripening, bitter peptides were degraded to rather small peptides or free amino acids. 4. Sensory evaluation of the 3 month ripended Cheddar cheese found no significant differences in color but the cheese made with mutant evidenced higher palatability in flavor and better texture than the control cheese. 5. The yields of the cheddar cheese made with mutant was 0.14% higher than that of the control cheese.

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A Study on the Water Quality Management of Modular Revetment Structure installed Low-Maintenance Constructed Wetland (플랜터형 호안구조물을 설치한 저관리형 습지의 수질 제어 기작에 관한 연구)

  • Ham, Eun Kyung;Choi, Yun Eui;Kim, Min;Chon, Jinhyung
    • Journal of Wetlands Research
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    • v.17 no.2
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    • pp.184-192
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    • 2015
  • This study is a basic research for low maintenance constructed wetlands which can prevent water quality deterioration due to wetland soils. The purpose of this study is to analyze water quality control mechanisms of constructed wetland on the artificial ground which installed the modular revetment structure(MRS), a device that separates water and soil. This study was then conducted with two different wetland mesocosms (a treatment plot and a control). These mesocosms were monitored to analyze effects of water quality control of the MRS. A treatment plot was built, and separated into soil and water, by filling the MRS with the decomposed granite soil in the mesocosm made of rubber material. A control plot was built where the decomposed granite soils were exposed to water by leaving the soil on the bottom of the mesocosm made of rubber material. Water quality was then analyzed by using Kolmogorov-Smirnov Z examination which then showed that pH, BOD, SS, Chl-a, T-P, T-N had statistically valid difference between a container with the MRS and one without it. According to the analysis of the water quality, the temperature and the EC level came out similarly and both mesocosm showed same level on pH and DO. A treatment plot had higher levels of BOD, SS Chl-a, and T-P. A control plot's T-N value was little lower than that of the treatment plot. This study suggests method of constructed wetlands using the MRS prevents problems occurring in wetland soils: aridity of wetlands by soil erosion, eutrophication, and algal blooms due to nutrients released from wetland soil. These functions of constructed wetland with the MRS increase aesthetic, ecologic, social, and economic value of the wetland. Outcomes of this research will later enable more proficient way of stabilizing water quality and provide data for planning low maintenance constructed wetlands.

Comparison of the Mineral Contents of Sun-dried Salt Depending on Wet Digestion and Dissolution (습식분해 및 직접용해법에 따른 천일염 중 무기성분 함량 비교)

  • Jin, Yong-Xie;Je, Jeong-Hwan;Lee, Yeon-Hee;Kim, Jin-Hyo;Cho, Young-Suk;Kim, So-Young
    • Food Science and Preservation
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    • v.18 no.6
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    • pp.993-997
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    • 2011
  • The aims of this research were to determine the proximate composition of various salts and to compare two digestion methods (direct digestion without heating, and microwave digestion) for the determination of the main mineral contents of various salts. Twelve salt samples were divided into three groups of four samples each (imported, Korean gray, and Korean white salts). As a result, the NaCl contents of the Korean white, Korean gray, and imported salts were 85.1, 89.3, and 91.3%, respectively. The salts in the three groups were analyzed for their main mineral contents via AAS. The sodium (Na) content of the Korean white salt was found to be slightly lower than that of the imported salt while the magnesium (Mg) and potassium (K) contents of the Korean white salt were found to be higher than those of the imported salt. The mineral composition (% Na:Mg) obtained using microwave-assisted digestion procedures, and the other dissolutions for the subsequent sample analysis, were 89:1 (for both the imported and Korean gray salts) and 82:3 vs. 81:3 (Korean white salt), respectively. The data regarding the mineral contents and composition of the sun-dried salts obtained through the analysis method of wet digestion and the dissolution procedure were compared, and no significant difference was found between the two datasets. Consequently, in this paper, a direct dissolution procedure is suggested for the analysis of the mineral composition of salt.