• Title/Summary/Keyword: Impact site

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Dispersive Wave Analysis of a Beam under Impact Load by Piezo-Electric Film Sensor and Wavelet Transform (충격하중을 받는 보에서 압전 필름센서와 웨이브렛 변환을 이용한 문산파동의 해석)

  • Kwon., Il-Bum;Choi, Man-Yong;Jeong., Hyun-Jo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.5 no.4
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    • pp.215-225
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    • 2001
  • Stress waves monitored on the surface of structures under various loading conditions can provide useful information on the structural health status. In this paper, stress waves are measured by several sensors when a steel beam is impacted by a ball drop. The sensors used include the piezo-electric film Sensor, the electrical strain gage, and the ultrasonic transducer, and special attention is given to the pieza film sensor. The wavelet transform is used for the time-frequency analysis of dispersive waves propagating in the beam. The velocities of the wave produced in the team due to the lateral impact is found to be frequency-dependent and identified as the flexural wave velocity based on the comparisons with the Timoshenko beam theory. A linear impact site identification method is developed using the flexural wave, and the impact sites of the beam can be accurately estimated by the piezo film sensors. It is found that the piezo film sensor is appropriate for sensing stress waves due to impact and for locating impact sites in the beam.

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Assessing the impact of air pollution on mortality rate from cardiovascular disease in Seoul, Korea

  • Park, Sun Kyoung
    • Environmental Engineering Research
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    • v.23 no.4
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    • pp.430-441
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    • 2018
  • The adverse health impact of air pollution is becoming more serious. The purpose of this study is twofold: One is to analyze the effect of air pollution and temperatures on human health by analyzing the number of deaths from cardiovascular disease in Seoul, Korea; the other is to determine what impact the location of a monitoring site has on the results of a health study. For this latter purpose, air pollution and temperature monitors are sited at three locations termed green, public, and residential. Then, a decision tree model is used to analyze factors linked with deaths occurring at each monitoring site. The results show that the environmental temperatures before death and the $PM_{2.5}$ concentrations on the day of death are highly linked with the number of deaths regardless of the monitoring location. However, results are most accurate with residential data. The results of this study can be used as base data for a similar analysis and ultimately, as a guide to minimize the health impact of air pollution.

Investigating the Moderating Impact of Hedonism on Online Consumer Behavior (탐색쾌악주의대망상소비자행위적조절작용(探索快乐主义对网上消费者行为的调节作用))

  • Mazaheri, Ebrahim;Richard, Marie-Odile;Laroche, Michel
    • Journal of Global Scholars of Marketing Science
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    • v.20 no.2
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    • pp.123-134
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    • 2010
  • Considering the benefits for both consumers and suppliers, firms are taking advantage of the Internet as a medium to communicate with and sell products to their consumers. This trend makes the online shopping environment a growing field for both researchers and practitioners. This paper contributes by testing a model of online consumer behavior with websites varying in levels of hedonism. Unlike past studies, we included all three types of emotions (arousal, pleasure, and dominance) and flow into the model. In this study, we assumed that website interfaces, such as background colors, music, and fonts impact the three types of emotions at the initial exposure to the site (Mazaheri, Richard, and Laroche, 2011). In turn, these emotions influence flow and consumers' perceptions of the site atmospherics-perception of site informativeness, effectiveness, and entertainment. This assumption is consistent with Zajonc (1980) who argued that affective reactions are independent of perceptual and cognitive operations and can influence responses. We, then, propose that the perceptions of site atmospherics along with flow, influence customers' attitudes toward the website and toward the product, site involvement, and purchase intentions. In addition, we studied the moderating impact of the level of hedonism of websites on all the relationship in the model. Thus, the path coefficients were compared between "high" and "low" hedonic websites. We used 39 real websites from 12 product categories (8 services and 4 physical goods) to test the model. Among them, 20 were perceived as high hedonic and 19 as low hedonic by the respondents. The result of EQS 6.1 support the overall model: $\chi^2$=1787 (df=504), CFI=.994; RMSEA=.031. All the hypotheses were significant. In addition, the results of multi-groups analyses reveal several non-invariant structural paths between high and low hedonic website groups. The findings supported the model regarding the influence of the three types of emotions on customers' perceptions of site atmospherics, flow, and other customer behavior variables. It was found that pleasure strongly influenced site attitudes and perceptions of site entertainment. Arousal positively impacted the other two types of emotions, perceptions of site informativeness, and site involvement. Additionally, the influence of arousal on flow was found to be highly significant. The results suggested a strong association between dominance and customers' perceptions of site effectiveness. Dominance was also found to be associated with site attitudes and flow. Moreover, the findings suggested that site involvement and attitudes toward the product are the most important antecedents of purchase intentions. Site informativeness and flow also significantly influenced purchase intentions. The results of multi-group analysis supported the moderating impacts of hedonism of the websites. Compared to low (high) hedonic sites, the impacts of utilitarian (hedonic) attributes on other variables were stronger in high (low) hedonic websites. Among the three types of emotions, dominance (controlling feelings) effects were stronger in high hedonic sites and pleasure effects were stronger in low hedonic sites. Moreover, the impact of site informativeness was stronger for high hedonic websites compared to their low-hedonic counterparts. On the other hand, the influence of effectiveness of information on perceptions of site informativeness and the impact of site involvement on product attitudes were stronger for low hedonic websites than for high hedonic ones.

A Case Study on Simplified Assessment Method for Site Selection of the Waste Treatment Facilities in Korea (폐기물 처리시설 입지선정의 효율화 방안에 관한 연구 - 여주군 폐기물 매립지 입지선정 사례를 중심으로 -)

  • Lee, Mu Choon;Koo, Ja Kon;Kim, Ki Cheol;Kwon, Yeon Jeong
    • Journal of Environmental Impact Assessment
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    • v.8 no.1
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    • pp.71-79
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    • 1999
  • The comparative evaluation is the most effective method for site selection because the selection of waste treatment facility is to determine the optimum site out of limited candidate sites. This study adopted the ordinal scale evaluation, one of methods of comparative evaluation. The ordinal scale evaluation aims to determine the investigating items referring to the character of sites, to determine the importance factors for investigating items, and to determine the optimum site according to the quantitative evaluation. As a result of this study, the defects of the former reports on the environmental characteristics, such as obscurity of meaning and subjective statement, were reduced by the ordinal scale evaluation which is one of the quantitative evaluation methods. This ordinal scale evaluation method has some valuable advantages, such as, to be able to consider the cost-effect efficiency, to consider the objectiveness and the clearness of the reports on the environmental characteristics. Therefore the reducement of social complications about site selection of the indisposed facilities could be expected by this study.

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Impact of Slash and Burning on Microbial Biomass in Semi-Evergreen Tropical Deciduous Forest of Manipur, North-East India

  • Yadava, P.S.;Devi, A.Sarjubala
    • The Korean Journal of Ecology
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    • v.27 no.4
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    • pp.225-230
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    • 2004
  • The impact of slash and burning on microbial biomass C, N and P in soils of semi-evergreen tropical deciduous forest were studied from February 1999 to January 2000. The experimental sites were located near Moreh town in the Chandel district of Manipur state (India) along the Indo-Myanmar border between 23° 49' N-24°28'N latitude and 93°45'E-94°16'E longitude. Microbial biomass C ranged from 319.50 ㎍ g/sup -1/ 905.50㎍ g/sup -1/ in the slash and burnt site and from 209.50 ㎍ g/sup -1/ to 708.80 ㎍ g/sup -1/ soil in the forest site. Microbial N ranged from 19.30 ㎍ g/sup -1/ to 99.45 ㎍ g/sup -1/ in the slash and burnt site and from 16.08㎍ g/sup -1/ to 88.90 ㎍ g/sup -1/ in the forest site. Microbial P varied from 10.90 ㎍ g/sup -1/ to 32.21 ㎍ g/sup -1/ in the slash and burnt site and from 2.50 ㎍ g/sup -1/ to 17.60 ㎍ g/sup -1/ in the forest site in different months throughout the year. Microbial biomass C, N and P were recorded to be higher in the slash and burnt site compared to the forest site The conversion of forest into slash and burnt site for agriculture - the traditional shilling cultivation practiced by tribal people in the north- eastern India leads to addition of large amount of organic matter in the soil thereby exhibiting higher values of microbial biomass C, N and P in the recent slash and burnt site than that of the forest site. Relationship between the soil moisture, soil organic C and microbial biomass C, N and P were found to be correlated significantly in both the sites.

Quantification of Ecological Impact as a Basis for Evaluation (독일에서의 환경영향의 정량적 평가)

  • Schweppe-Kraft, Burkhard
    • Journal of Environmental Impact Assessment
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    • v.2 no.2
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    • pp.59-71
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    • 1993
  • Evaluation methods are employed in environmental impact assessment to choose between different project site, to determine the required measures to compensate impact and to decide whether the environmental impacts are more important than the social or economic effects of a project. The main obstacles that restrict use of quantitative evaluation method are a Lack of knowledge about the environmental effects (e.g. if impacts on wildlife or landscape amenities are predicted) and the relative importance of economic and social issues compared with nature conservation stability of ecosystem or landscape beauty. In Germany, the most common method for site planning is the "ecological risk analysis". It is a kind of multi-criteria-decision-method based on quantitative and qualitative description and ordinal ranking. The various kinds of "ecological balancing methods" that are more recently developed (within the last decade) to quantify the required amount for compensatory measures instead often use cardinal figures to express the value of ecosystems, the intensity of impacts, the need for additional measures to compensate for long recuperative periods when restoring ecosystems and so on. There are still only a view attempts to quantify decisions between environmental and socio-economic issues. Multicriteria-analysis as well as cost-benifit-analysis was used. Some new approaches which are still in a preliminary status are based on contingent valuation and on calculations for compensatory payments (instead of compensatory measures).

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A Study on the Evaluation of the Environmental Impact of Energy Usage in Construction Sites (건설현장 내 에너지 사용량에 따른 환경영향 평가에 관한 연구)

  • Lee, Chung-Won;Tae, Sung-Ho;Jang, Hyeong-Jae;Lim, Hyo-Jin;Kim, Hyeon-Suk
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2022.11a
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    • pp.119-120
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    • 2022
  • As the seriousness of the climate crisis is emphasized, movements to solve it are becoming active. In Korea, efforts to reduce environmental impacts across all industries are being strengthened through the Framework Act on Low Carbon Green Growth. The construction industry predicts the environmental impact of buildings during the entire life cycle, but in the construction process, there is a difference in energy usage depending on the amount of input, and it is difficult to predict the environmental impact if data cannot be collected. Therefore, this study evaluated the environmental impact of energy usage in the apartment construction process as part of the study on predicting and reducing the environmental impact of the construction process of the construction site. To this end, the environmental effects of buildings were set as global warming, resource consumption, and ozone layer effects, and the environmental effects of the actual energy use in the case were evaluated. In addition, based on the evaluation results, the characteristics of the input energy usage were compared and analyzed.

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Forest Floor Biomass, Litterfall and Physico-chemical Properties of Soil along the Anthropogenic Disturbance Regimes in Tropics of Chhattisgarh, India

  • Oraon, P.R.;Singh, Lalji;Jhariya, Manoj Kumar
    • Journal of Forest and Environmental Science
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    • v.34 no.5
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    • pp.359-375
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    • 2018
  • The long term ecological effects have been reported in natural forest ecosystem due to various anthropogenic disturbances, especially in tropics of the world. The present study was carried out in the sanctuary area of central India to assess the changes on litter biomass, litterfall pattern and soil attributes under different disturbance regimes. The study area includes three forest circles i.e., Bhoramdeo, Jamunpani and Salehwara each comprising three disturbances regimes viz., high, medium and low severity of biotic pressure. A noticeable variation and impact were recorded in different sites. The impact varies significantly from least disturbed sites to highly disturbed sites across the circle and among different disturbances level. The seasonal mean total forest floor biomass across the forest circles varied from 2.18 to $3.30t\;ha^{-1}$. It was found highest under lightly disturbed site and lowest under heavily disturbed site. Total litterfall varied from 5.11 to $7.06t\;ha^{-1}\;yr^{-1}$ across the forest circle. Lowest litterfall was recorded at heavily disturbed site while highest in lightly disturbed site. Annual turnover of litter varied from 69-73% and the turnover time ranged between 1.37-1.45 years. The turn over time was higher for heavily disturbed site and lower for lightly disturbed site. The heavily disturbed site of all the circle showed the sandy loam soil texture, whereas moderately and lightly disturbed site comprised of sandy loam, sandy clay loam and clay soil texture, respectively. The bulk density decreases from heavily disturbed site to lightly disturbed site and the pH of soils ranged from 5.57-6.89 across the circle. Across the circle the total soil nitrogen ranged from 0.12-0.21%, phosphorus from 10.03-24.00 kg and Potassium from $139.88-448.35kg\;ha^{-1}$, respectively. Our results demonstrate that anthropogenic disturbances regime significantly influences forest floors in terms of mass, composition and dynamics along with litterfall rate and soil properties.

The impact of the alveolar bone sites on early implant failure: a systematic review with meta-analysis

  • Fouda, Atef Abdel Hameed
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.46 no.3
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    • pp.162-173
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    • 2020
  • Dental implants are the first option for replacement of missing teeth. Failure usually involves additional cost and procedures. As a result, the physician should limit the risk factors associated with implant failures. Implant site is one of many factors that can influence the success or failure of dental implants. The association between early implant failure (EIF) and implant site has yet to be documented. This review aims to estimate the impact of insertion site on the percentage of EIFs. An electronic and manual search of studies that reported early failure of dental implants based on collection site. A total of 21 studies were included in the review and examined for the association between EIF and alveolar site. Subgroup analysis, including a comparison between implants inserted in four alveolar ridge regions of both jaws was performed. The early failure rate was higher for maxillary implants (3.14%) compared to mandibular implants (1.96%). Applying a random effect, risk ratio (RR), and confidence interval (CI) of 95% revealed higher failure in the maxilla compared to the mandible (RR 1.41; 95% CI [1.19, 1.67]; P<0.0001; I2=58%). The anterior maxilla is more critical for early implant loss than other alveolar bone sites. Implants in the anterior mandible exhibited the best success rate compared of the sites.

A study on the dose evaluation of critical groups for unrestricted reuse of the site after the decommissioning of Kori Unit 1

  • Hyung-Woo Seo;Gang-Woo Ryu;Young-Il Na;Chan-Geun Park;Jin-Won Son;Cheon-Woo Kim
    • Nuclear Engineering and Technology
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    • v.56 no.8
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    • pp.3359-3368
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    • 2024
  • In the calculation of DCGLs using RESRAD code, the selection of input parameter values is paramount, which is basically possible when specific measures for selecting reuse scenarios and probabilistic evaluation methods are established. When referring to the impact of the age group considered in the environmental impact assessment among the existing operations of the plant, it may also need to be applied in the decommissioning project, and there will be considerations along with site reuse scenarios and probabilistic evaluations. Therefore, the main purpose of this study is to distinguish the types of exposure affected by residual radioactivity contamination during the process of deriving DCGL to be used in the final site release stage of NPPs and to evaluate them by reasonably assigning age group parameter values. In addition, the case of entering a single value for parameter values by age group and the case of entering probabilistic distributions were compared and analyzed.