• Journal of Korean Society on Water Environment
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• v.31 no.6
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• pp.723-731
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• 2015

We investigated the spatial and temporal patterns of water quality in the Gangjung-Goryoung weir that is located in the middle area of the Nakdong river, Korea. The monitoring results indicated that there are discernible vertical differences in water quality during the pre- and post-monsoon periods (May to September). During this period, it was observed that the weak thermal stratification formed at the maximum level, and pH, Chl-a, and DO concentrations in the surface layer were higher than those in the bottom layer. This vertical difference was especially noticeable for DO concentrations: there were DO depletions at the bottom layer in late June to early August. During the summer monsoon period with heavy rainfall, there was a decline in vertical differences in water quality. From this study, it was suggested that continuous monitoring of vertical profiles could become a useful tool for identifying the spatial and temporal distributions of water quality and for developing the best management policy for water quality in the Nakdong river.

• Nuclear Engineering and Technology
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• v.54 no.6
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• pp.2077-2083
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• 2022

In the unlikely event of core disruptive accident in sodium cooled fast reactors, the reactor containment building would be bottled up with sodium and fission product aerosols. The behavior of these aerosols is crucial to estimate the in-containment source term as a part of nuclear reactor safety analysis. In this work, the evolution of sodium aerosol characteristics (mass concentration and size) is simulated using HAARM-S code. The code is based on the method of moments to solve the integro-differential equation. The code is updated to FORTRAN-77 and run in Microsoft FORTRAN PowerStation 4.0 (on Desktop). The sodium aerosol characteristics simulated by HAARM-S code are compared with the measured values at Aerosol Test Facility. The maximum deviation between measured and simulated mass concentrations is 30% at initial period (up to 60 min) and around 50% in the later period. In addition, the influence of humidity on aerosol size growth for two different aerosol mass concentrations is studied. The measured and simulated growth factors of aerosol size (ratio of saturated size to initial size) are found to be matched at reasonable extent. Since sodium is highly reactive with atmospheric constituents, the aerosol growth factor depends on the hygroscopic growth, chemical transformation and density variations besides coagulation. Further, there is a scope for the improvement of the code to estimate the aerosol dynamics in confined environment.

• Earthquakes and Structures
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• v.2 no.4
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• pp.377-396
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• 2011

In seismic design and structural assessment using the displacement-based approach, real structures are simplified into equivalent single-degree-of-freedom systems with equivalent properties, namely period and damping. In this work, equations for the optimal pair of equivalent properties are derived using statistical procedures on equivalent linearization and defined in terms of the ductility ratio and initial period of vibration. The modified Clough hysteretic model and 30 artificial accelerograms, compatible with the acceleration spectra for firm and soft soils, defined by the Japanese Design Specifications for Highway Bridges are used in the analysis. The results obtained with the proposed equations are verified and their limitations are discussed.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.740-741
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• 2015

the downscaled air temperature data over study region for the projected 2001 - 2099 period were then ensemble averaged, and the ensemble averages of 6 realizations were compared against the corresponding historical downscaled data for the 1961 - 2000 period in order to assess the impact of climate change on air temperature over study region by graphical, spatial and statistical methods. In order to evaluate the seasonal trends under future climate change conditions, the simulated annual, annual DJF (December-January-February), and annual JJA (June-July-August) mean air temperature for 5 watersheds during historical and future periods were evaluated. From the results, it is clear that there is a rising trend in the projected air temperature and future air temperature would be warmer by about 3 degrees Celsius toward the end of 21^st century if the ensemble projections of air temperature become true. Spatial comparison of 30-year average annual mean air temperature between historical period (1970 - 1999) and ensemble average of 6-realization shows that air temperature is warmer toward end of 21^st century compared to historical period.

• Journal of Soil and Groundwater Environment
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• v.22 no.6
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• pp.37-47
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• 2017

Climate change has often resulted in severe droughts in a rice-farming season (i.e., April to June), and the large amount of water resources were needed to cope with droughts during the season. Therefore, the subsurface dam, which is able to store groundwater resources in the alluvium aquifer, has been considered to be an alternative for securing more groundwater resources. In this study, suitable sites assessment criteria for agricultural subsurface dam using analytic hierarchy process (AHP) were established for adequate drought management. Moreover, the criteria were applied to the existing five agricultural subsurface dams to verify their applicability of groundwater supply for each subsurface dam. The assessment criteria were divided into three major categories (geology, hydrology and business condition) and classified to 12 individual sub-categories with weighting. From the assessment, Ian subsurface dam and Wooil subsurface dam were identified as the best and the worst suitable site, respectively, and this result was in accordance with the average amount of annual groundwater supply by each subsurface dam during the period of 2011-2017.

• Journal of the Society of Naval Architects of Korea
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• v.59 no.2
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• pp.89-95
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• 2022

The stability of the existing ships has been evaluated through numerical calculations in the steady-state, but recently the IMO proposed a new stability assessment criteria that the stability is evaluated in the state in which environmental loads from such as waves and wind act like the loads under actual ship operating conditions. In this study, IMO 2nd generation stability assessment method and procedure were summarized for the dead ship condition, and Direct Stability Assessment (DSA) was performed on 13K chemical tanker through basin model test. The model test is performed in the ocean engineering basin to implement wave and wind loads, and environmental conditions for waves were set height and period of the incident wave, considering the regular wave and wind generation range reproducible in the ocean engineering basin. In addition, to consider the effect of wind speed, the Beaufort Scale for wind speed was applied in the model test.

• Journal of Environmental Impact Assessment
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• v.18 no.3
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• pp.151-160
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• 2009

In order to use fundamental data for conservation of species diversity and stream health with dam development, fish investigation in up- and downstream of Pyeonglim Dam was seasonally conducted in 2007~2008. In addition, data of water qualities, investigated for environmental impact assessment, were used to determine a water quality standard level in Pyeonglim Stream, and it revealed that water environment condition was good in the stream. During the study period, a total number of fish caught from the 4 study sites was 5,449 representing 9 families 25 species, and there were 8 Korean endemic species (32.0%) including Rhodeus uyekii, Squalidus gracilis majimae, and Microphysogobio yaluensis. Two species of Zacco temminckii (37.5%) and Zacco platypus (26.3%) were dominant and subdominant in all sites. There were few individuals of the $2^{nd}$-class endangered species (Sand lamprey, Lampetra reissneri) and the introduced species (Bluegill, Lepomis macrochirus), found in the upstream of the dam. and further investigation for conservation of the endangered species and for prevention of the introduced species is needed in future. With fish fauna and multi-metric health assessment model in each sampling attempt, index of biotic integrity(IBI) was evaluated and it resulted mostly in good(26~35) and excellent(36~40) condition in all sites. The results indicate that it is very important to study not only environmental impact assessment with fish composition but also stream health assessment in order to conserve healthy aquatic ecosystem.

• Convergence Security Journal
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• v.6 no.3
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• pp.97-106
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• 2006

We have been setting in The age of Ubiquitous that people are able to connect networks whenever and wherever by developing network. We can take any classes anytime we want even right checking out the result of a test through the internet with the spread of networks. The development of net-works has created WBI(Web Based Instruction) which has covered the limit of conservative education for instance, there are some content differences whenever a teacher teaches for each class, it is hard to take a lesson after having a certain period, the process of the class is changed as time goes by and so on. As the study of WBI is actively being worked in this moment, a various of class models are showing and materializing. In WBI, the exiting Objective Checking Assessment is applicable, some of the Performance Assessment which inspects and judges students' actual performance is Working whereas teachers who actually give them points don't have a embodied Performance Assessment Program. In this paper, I will present a Performance Assessment to use conveniently Performance Assessment Program not just students carrying out Performance Assessment using the internet but also teachers dealing with actual administrative works.

• Sleep Medicine and Psychophysiology
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• v.13 no.1
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• pp.22-26
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• 2006

Circadian rhythms have been observed to be disturbed in mood disorders, especially seasonal affective disorder (SAD). Clock related gene variants also have been suggested to be associated with seasonality (seasonal variations in mood and behavior). This study tested the potential association between a length polymorphism of Period3 gene and seasonal variations in mood and behavior. 297 Korean college students were genotyped for the Period3 polymorphism and were for evaluated the seasonal variation by Seasonal Pattern Assessment Questionnaire (SPAQ). The genotype frequencies were 0.76 for 4R/4R, 0.22 for 4R/5R and 0.013 for 5R/5R. The global seasonality score was not different among Period3 gene variants (4R/4R, 4R/5R and 5R/5R) except for 'sleep length' subscore. The 5R/5R genotype showed the higher 'sleep length' subscore than others (p=0.024). The comparison between seasonals (syndromal plus subsyndromal SAD determined by SPAQ) and non-seasonals did not show any significant difference in frequencies of genotypes. These findings suggest that there is a possibility that the investigated Period3 polymorphism may play a partial role in the susceptibility of seasonal variations in a Korean population.

• Therapeutic Science for Rehabilitation
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• v.11 no.2
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• pp.7-24
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• 2022

Objective : To develop standardized assessment tools that evaluate the multi-aspect lifestyles of children and adolescents, we aimed to systematically analyze lifestyle assessment tools and lifestyle component-specific assessment tools. Methods : The study period was 2001-2020, with search engines using CINANL, NDSL, PubMed, and RISS. Search key words used 'lifestyle assessment' OR 'lifestyle profile' OR 'lifestyle test', 'physical activity assessment' OR 'physical activity participation profile', 'nutrition assessment' OR 'nutrition profile', 'activity participation assessment' OR 'activity participation profile'. Results : A total of 24 evaluation tools were selected after 5,883 studies reviewed the title, abstract, and full text after deduplication. The detailed results resulted in five lifestyle assessment tools, seven physical activity assessment tools, nine nutrition assessment tools, and three activity participation assessment tools. Conclusion : For the lifestyle assessment tools for children and adolescents, the component items, measurement methods, and age of assessment of each item were analyzed. It is hoped that this will be used as a basis for the development of standardized assessment tools to assess the multi-aspect lifestyles of children and adolescents in the future.