• Economic and Environmental Geology
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• v.54 no.4
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• pp.409-425
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• 2021

Carbon dioxide has been known to be a typical greenhouse gas causing global warming, and a number of efforts have been proposed to reduce its concentration in the atmosphere. Among them, carbon dioxide capture and storage (CCS) has been taken into great account to accomplish the target reduction of carbon dioxide. In order to commercialize the CCS, its safety should be secured. In particular, if the stored carbon dioxide is leaked in the arable land, serious problems could come up in terms of crop growth. This study was conducted to investigate the effect of carbon dioxide leaked from storage sites on soil fertility. The leakage of carbon dioxide was simulated using the facility of its artificial injection into soils in the laboratory. Several soil chemical properties, such as pH, cation exchange capacity, electrical conductivity, the concentrations of exchangeable cations, nitrogen (N) (total-N, nitrate-N, and ammonia-N), phosphorus (P) (total-P and available-P), sulfur (S) (total-S and available-S), available-boron (B), and the contents of soil organic matter, were monitored as indicators of soil fertility during the period of artificial injection of carbon dioxide. Two kinds of soils, such as non-cultivated and cultivated soils, were compared in the artificial injection tests, and the latter included maize- and soybean-cultivated soils. The non-cultivated soil (NCS) was sandy soil of 42.6% porosity, the maize-cultivated soil (MCS) and soybean-cultivated soil (SCS) were loamy sand having 46.8% and 48.0% of porosities, respectively. The artificial injection facility had six columns: one was for the control without carbon dioxide injection, and the other five columns were used for the injections tests. Total injection periods for NCS and MCS/SCS were 60 and 70 days, respectively, and artificial rainfall events were simulated using one pore volume after the 12-day injection for the NCS and the 14-day injection for the MCS/SCS. After each rainfall event, the soil fertility indicators were measured for soil and leachate solution, and they were compared before and after the injection of carbon dioxide. The results indicate that the residual concentrations of exchangeable cations, total-N, total-P, the content of soil organic matter, and electrical conductivity were not likely to be affected by the injection of carbon dioxide. However, the residual concentrations of nitrate-N, ammonia-N, available-P, available-S, and available-B tended to decrease after the carbon dioxide injection, indicating that soil fertility might be reduced. Meanwhile, soil pH did not seem to be influenced due to the buffering capacity of soils, but it is speculated that a long-term leakage of carbon dioxide might bring about soil acidification.

• Food Science and Preservation
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• v.20 no.3
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• pp.323-329
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• 2013

Strawberries are among the leading ready-to-eat agricultural products that have superior taste and nutrition. Thus, consumer concerns about the safety of eating strawberries are growing. To evaluate the contamination levels of strawberries according to their cultivation methods (nutriculture, pesticide-free culture and organic farming) and parts [fruit (flesh), stalk (pedunle) and leaf (calyx)], 1,020 parts of strawberry samples were collected at 12 farms in Nonsan-si and quantitatively or qualitatively examined for the indicators of food safety and food poisoning bacteria. The total aerobic bacteria count in the whole samples was 2.3~6.8 ${\log}_{10}$ CFU/g, and coliform bacteria were detected in 14.2% of the whole samples with a contamination level range of 2.1~4.5 log CFU/g. E. coli were detected in 0.9% of the whole samples with a contamination level range of 2.1~2.8 log CFU/g. The analysis of the bacterial levels according to the cultivation methods showed that the total aerobic bacteria and coliform counts were higher in the strawberries that were grown via organic farming than in those that were grown via nutriculture and pesticide-free culture. However, the E. coli counts of the strawberries that were grown via organic farming and via pesticide-free culture were similar and differed from that of the strawberries that were grown via nutriculture. The analysis of the contamination levels according to the parts of the strawberries showed that the total aerobic bacteria, coliform and E. coli counts of the fruits, stalks and leaves of the strawberries did not significantly differ. Staphylococcus aureus was detected in two organically grown strawberries, but Salmonella spp., Listeria monocytogenes and E. coli O157:H7 were not detected in the whole samples. These results show that the bacterial contamination levels of the strawberries differed based on their cultivation methods. Thus, a suitable method of reducing the bacterial contamination levels of strawberries according to their farming methods is needed.

• Journal of Food Hygiene and Safety
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• v.13 no.4
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• pp.430-440
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• 1998

The average number of total viable counts for the commercial pork tested was 19/g, coliform 1.8/g, psychrophilic bacteria 15/g, heterotrophic bacteria 12/g, fecal streptococcus 6.2/100 g, Pseudomonas aeruginosa 13/100 g and none of heat-resistant bacteria and Staphylococcus was detected. That for the commercial beef tested was 130/g, coliform 5.2/g, psychrophile 140/g, heterotroph 28/g, Staphylococcus 1.2/g, fecal streptococcus 9.5/100 g, Pseud. aeruginosa 1.9/100 g and heat-resistant bacteria was not detected. That for the commercial chicken tested was 8800/g, coliform 53/g, psychrophile 4600/g, heterotroph 4700/g, fecal streptococcus 9.9/100 g, Pseudo aeruginosa 2.5/100 g. That for milk was 4700/ml, psychrophile 120/ml, heterotroph 420/ml and the others were not detected. That for the commercial cheese was 3.2/g, psychrophile 2.3/g, heterotroph 1.6/g, Staphylococcus l/g, fecal streptococcus 9.1/g. That for fermented milk was $10^{7}/ml$, heatresistant bacteria $10^{6}/ml$, fecal streptococcus 2400/100 ml, lactobacillus $3.2{\times}10^{15}/ml$, in accordance with lactic acid bacteria and the others were not detected. There was not detected any indicator organisms from ham, sausage, butter, eggs and quails in the commercial fooods tested. SPC, coliform, psychrophile and heterotroph in commercial meats stored at $10^{\circ}C$ were increased rapidly as time goes on but heat-resistant bacteria, staphylococcus, fecal streptococcus and Pseudo aeruginosa were constant. At $20^{\circ}C$, SPC, coliform, psychrophile, heterotroph and fecal streptococcus were the highest at 7 days and heat-resistant bacteria, staphylococcus and Pseudo aeruginosa were increased a little. At $30^{\circ}C$, all indicators were increased rapidly for 3 and 7 days and then decreased rapidly. All indicator organisms were increased at the level of 10/g for 14 days in meat products stored at $10^{\circ}C$, but SPC, psychrophile and heterotroph in meat products stored at $20^{\circ}C$ were increased at the level of $lO^5/g$. It showed that the indicators in meat products stored at $30^{\circ}C$ had a tendency to increase at the level of $10^{2}/g$ relative to those stored at $20^{\circ}C$. SPC, psychrophile and heterotroph in milk stored at $10^{\circ}C$ increased up to the level of $10^4/ml$, but coliform, staphylococcus, fecal streptococcus and Pseudo aeruginosa were not detected. As stored at $20^{\circ}C$ and $30^{\circ}C$, they were increased rapidly for 1 or 3 days and then constant for a long time.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.4
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• pp.403-413
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• 2007

As rock bolts become one of the main support systems in tunnels and underground structures, the integrity of the rock bolts affects the safety of these types of structures. The purpose of this study is the evaluation of rock bolt integrity using Fourier and wavelet transforms of the guided ultrasonic waves. After five rock bolt specimens with various defect ratios are embedded into a large scale concrete block, guided waves are generated by a PZT (lead zirconate titanate) element and measured by an acoustic emission (AE) sensor. The captured signals are analyzed in the frequency domain using the Fourier transform, and in the time-frequency domain using the wavelet transform based on a Gabor wavelet. The spectrum obtained from the Fourier transform shows that a portion of high frequency contents increases with increase in the defect ratio. Peak values in the time-frequency domain represent the interval of travel time of each echo. The energy velocities of the guided waves increase with the defect ratio. This study shows that the spectrum ratio and the energy velocity may be indicators fur the evaluation of rock bolt integrity.

• Journal of Korean Society of Transportation
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• v.31 no.4
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• pp.32-46
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• 2013

Because of short length between interchanges, traffic congestion has been caused by a lot of short trip traffic in the urban section of interregional expressway. Also, in case of expressway with Bus Only Lane, bus causes dangerous situation by conflicting between vehicles and buses in order to access from Bus Only Lane to IC. Therefore, this study aims to propose Express Lane applied by Bus Only Lane as a new lane operation in order to efficiently operate and to analyze the effectiveness on constructing Express Lane to the Pangyo-Hannam section in Gyeongbu Expressway. The study analyzes effectiveness by scenario using the micro traffic simulation tool, VISSIM 5.4. For this, the indicators which evaluate construction effect of Express Lane, are used by average delay time, average speed and total travel time. The results of the study showed the best effectiveness when Express Lane installed one, and it represented an ideal traffic condition when long distance trip traffic of the whole traffic is 25% in the study section. Therefore, the construction of Express Lane using Bus Only Lane achieves positive effectiveness on safety and expense aspect as well as uncongested flow.

• The Korean Journal of Food And Nutrition
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• v.29 no.6
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• pp.849-859
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• 2016

Edible insects have gained recognition worldwide as complementary protein sources. Recently, four edible insects were newly allowed to be used as food materials in Korea: the mealworm (Tenebrio molitor), the cricket (Velarifictorus asperses), the white-spotted flower chaffer beetle larva (Protaetia brevitarsis seulensis), and the rhinoceros beetle larva (Allomyrina dichotoma). In this study, we evaluated the oxidative stabilities of these four edible insects during cold storage. The insects were sacrificed by blanching for 3 minutes in boiling water. The blanched insects were then stored at $4^{\circ}C$ in an incubator for 42 days. The color values, titratable acidity, peroxide values, acid values, TBARS, contents of VBN, and total plate counts of the insects were measured at days 0, 2, 4, 7, 10, 14, 21, 28, 35, and 42, respectively. Blanching decreases oxidative stresses during storage. At day 0, the white-spotted flower chaffer beetle larva showed the highest values for acid value, TBARS, VBN, and microbial counts. Most of the oxidative indicators were significantly changed at day 14 in all four insects, possibly related with the growth on all microbial plates. Based on microbial safety and the oxidative stabilities of lipids and proteins, optimal storage conditions for the cricket, the white-spotted flower chaffer beetle larva, and the rhinoceros beetle larva were 10~14 days at $4^{\circ}C$. Likewise, the mealworm showed rapid oxidation after day 14, but poor qualities were not observed until day 28.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.2
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• pp.47-58
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• 2013

The purpose of this study is to categorize the types of sidewalk cafes, and to evaluate design factors with types of sidewalk cafes for street revitalization. Consequently, it may suggest efficient and systemic policies for the guidelines of sidewalk cafes. To ensure this end, the types of sidewalk cafes were categorized from the street relationship perspective by site investigation. A literature review and importance analysis were used to select the evaluation criteria, and the data were analyzed by statistic methods such as descriptive analysis and factor analysis. As a result, five main factors of the evaluation criteria were contracted: accessibility, aesthetics, identity, environmental, culturedness. Cumulative factor loading of these five factors was 68.731%, which was quite high. And the evaluation using the Likert scale was performed by 4 experts. Types of sidewalk cafes were categorized into 5 types: protruding, gating, blending stereoscopic, elevation angle, and sign provision from the street relationship perspective. On the evaluation by type, aesthetics and culturedness were the worst evaluated in the protruding type and the gating type, culturedness was the worst in the blending stereoscopic type, accessibility, aesthetics, culturedness were the worst in the elevation angle type, and accessibility, identity, culturedness were the worst in the sign provision type. On the evaluation by the indicators, culturedness was the worst evaluated, and on the evaluation by criteria, 'safety for impaired persons', 'interest of programs', 'openness of entrance' were the worst. It is recommended that a survey of importance-performance analysis focused on users be conducted.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.2D
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• pp.137-145
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• 2012

According to the National Police Agency, the total number of traffic accidents which occurred in 2010 was 226,878. Intersection accidents accounts for 44.8%, the largest portion of the entire traffic accidents. An research on the signalized intersection is constantly made, while an research on the unsignalized intersection is yet insufficient. This study selected traffic volume, road width, and sight distance as the input variables which affect unsignalized intersection accidents, and number of accidents as the output variable to build a model using ANFIS(Adaptive Neuro-Fuzzy Inference System). The forecast performance of this model is evaluated by comparing the actual measurement value with the forecasted value. The compatibility is evaluated by R2, the coefficient of determination, along with Mean Absolute Error (MAE) and Mean Square Error (MSE), the indicators which represent the degree of error and distribution. The result shows that the $R^2$ is 0.9817, while MAE and MSE are 0.4773 and 0.3037 respectively, which means that the explanatory power of the model is quite decent. This study is expected to provide the basic data for establishment of safety measure for unsignalized intersection and the improvement of traffic accidents.

• Journal of Korean Society of Transportation
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• v.32 no.6
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• pp.628-637
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• 2014

The purpose of this study is to investigate the actual conditions of the mobility convenience facilities for pedestrians and their perception of the facilities, and thereby provide fundamental material necessary to establish a strategy of improving mobility convenience facilities. This study tried to analyze the characteristics of the mobility convenience facilities for pedestrians. Based on previous studies and "Report of Mobility Facilities of the Mobility Handicapped", this study first chose the evaluation items related to mobility convenience facilities, and then conducted a questionnaire survey and Importance-Performance Analysis (IPA). According to the study results, first, the item that needs intensive improvement was sidewalks, and the detailed indicators for sidewalks were walking safety, convenient facilities for the disabled, and pavement in order. Secondly, the items that need to be maintained were bus and crossroad. Thirdly, the low-ranking items were under-passageway and pedestrian overpass. And lastly, the items that need to be controlled were facilities for passenger terminals and bus terminals. Based on the comprehensive IPA result, this researcher judged the actual use conditions of the mobility convenience facilities in Buyeo-gun, Chungcheongnamdo. Therefore, it was found that it would be urgent to improve the direct walking environment on sidewalks. In this aspect, for future policy decision and facility maintenance, it is desirable to put the item in priority in terms of investment and come up with an improvement strategy.

• Ecology and Resilient Infrastructure
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• v.6 no.4
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• pp.227-235
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• 2019

This study monitored Daecheong 1-bo, Daecheong-stream, which carried out the project in 2014, from 2015 to 2016. The technology applied to the stream was evaluated using Periphytic Algae to check contamination indicators and ecological health of the area with an integral river-bed protection using non-toxic materials. The water quality of the monitoring section was confirmed to be above the river environment standard (II), and it was confirmed that the Saproxenic taxa of the river bed protection were higher than the upper and downstream sections. The TDI, which is an index of attachment algae, was shown in the average 51.03 and 52.15 for the pilot project sections in 2015 and 2016, confirming that the index is of the "normal" grade. This is the other sections in the upstream and downstream sections showed higher than "bad", which is thought to have a positive effect on the habitat of the river ecosystem components, especially the microbial population in river bed protection.