• Journal of Soil and Groundwater Environment
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• v.18 no.6
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• pp.48-55
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• 2013

This study aimed at characterizing unsaturated zone at the source zone area contaminated by DNAPL and investigating feasibility of soil vapor extraction (SVE). Five boreholes with three multi-level screens at the depth of 3.0~4.5 m, 5.5~7.0 m, and 8.0~12.0 m were installed at the source zone. Pneumatic tests were performed to determine the permeability of porous medium. Permeability was estimated to be 81.6 to 203.7 darcy, depending on the applied solutions, which was contradicted by grain size analysis of cored soil samples leading to 3.51 darcy. This is due to air flow through gravel pack during the early stage of pneumatic test. Pressure-drawdown curve in the late stage also well showed the leaky aquifer type, indicating air leakage to the ground. Air flow tests were also carried out to investigate air flow connectivity between multi-level wells, indicating that the horizontal air flow was well developed between the lower screens of the wells, not between the upper and middle screens due to the leakage to the surface. For the SVE test, there was no noticeable variation in TCE vapor concentration between three different test runs: 1. 8 hours daily for 5 days, 2. 24 hours together with air blowing at another well (BH1), 3. five consecutive days. Even for five-day consecutive test, total amount of removed TCE was estimated only to be as low as 46.5 g.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.105-112
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• 2007

Recently developed raised floor heating system is not only capable of basic function to reduce noise between floors, but also is a multi-functional floor heating system enabling natural ventilation. The procedure of this system for natural ventilation is to import outdoor air through bottom space of the floor heating system, circulate indoor space and discharge it out of ceiling. In winter, powerless natural ventilation is possible with buoyancy effect caused by temperature difference between outdoor and indoor. And it also allows saving of energy by importing pre-heated air in bottom space of the floor heating system. To evaluate ventilation performance of this system, on-site measurement was conducted in 2 test laboratories, and the nominal air change rate was satisfied as 0.4$\sim$0.8 h-1 under the condition of outdoor temperature $5^{\circ}C{\sim}-5^{\circ}C$, which was evaluated as highly possible to be applied as a natural ventilation system in multi-family houses.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.713-718
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• 2007

Structural tests often involve a large amount of complicated information. Data models can be used to efficiently organize the information. This paper briefly describes a data model for structural tests including hybrid tests, performed by the Real-Time Multi-Directional (RTMD) facility at the ATLSS Center of Lehigh University in America. The RTMD facility is an equipment site within the George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES). The data model is called the Lehigh Model. An overview of classes and attributes of the Lehigh Model is presented, and the Lehigh Model is compared with other data models to show its benefits for structural testing.

• 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.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.4
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• pp.247-256
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• 2012

The purpose of this study is to decide the permeability and the rate of flow in a way of both site investigation and backward analysis and the most reasonable numerical analysis by performing a seepage model test for measuring the deformation swept volume of the embankment body in order to review a stability of the sea dyke being composed of multi-layers depending on variation of infiltration. As a result of the review, it could be forecasted that sweeping loss would be taken place at the boundary between bed protection works and embankment materials of the sea dyke due to a permeability difference of the multi-layered bed foundation structures and the sea dyke deformation would be occurred as a result thereby. As result of a numerical analysis for the seepage model test, it could be observed that critical velocity method was found to be smaller than the numerical analysis value but its tendency was similar and therefore it was judged that this method could be applied for the actual cross section.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.3
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• pp.372-379
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• 2013

In this study, we investigated the traits of the clad metals used in hot-rolled clad steel plates. We examined the sensitization and mechanical properties of STS 316 steel plate and carbon steel (A516) under the specific circumstances of post heat treatment and whether a weld was multilayered and thick or repeated because of repairs. The test conditions were as follows. The clad steel plates were butt-welded using FCAW/SAW, and the heat treatment was conducted at $625^{\circ}C$, for 80, 160, 320, 640, or 1280 min. The change in the corrosion resistance was evaluated in these specimens. In the case of the carbon steel (A516), as the heat treatment time increased, the annealing effect caused the tensile strength to decrease. The micro- hardness gradually increased and then decreased after 640 min. The elongation and contraction of the area increased gradually. An oxalic acid etch test and EPR test on STS316, a clad metal, showed a STEP structure and no sensitization. From the test results for the multi-layered and repair welds, it could be concluded that there is no effect on the corrosion resistance of clad metals. In summary, the purpose of this study was to suggest some considerations when developing on-site techniques and evaluate the sensitization of stainless steels.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.10a
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• pp.574-584
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• 2006

Bi-directional loading test data are available to evaluate the design parameters which reflect the characteristics of a construction method and the variations of ground at the site where drilled shafts are installed. The method to obtain the design parameters of a real bridge by hi-directional loading test was introduced. The plans of multi-level testing and installation of measuring instruments should be made according to the rough estimation of axial bearing capacity, the length of pile, and the construction method. While the relationship between end bearing resistance and displacement was obtained directly from the hi-directional loading test, the relationship between unit side resistance and displacement was calculated through the measuring values. 1% displacement of pile diameter was adopted as the criteria of failure for ultimate resistance. As the settlement of pile head at the total ultimate bearing capacity obtained from these method was less than 1.5 % of pile diameter, this method was conservative to use in the field.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.6
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• pp.278-282
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• 2010

The doping effect of thulium on electrical properties and degradation behavior in barium titanate ceramics ($BaTiO_3$) was investigated in terms of generations of core-shell structure and micro-chemical changes through highly accelerated degradation test. The dielectric specimens of pellet type and multi-layered sheets were prepared by using $BaTiO_3$ with undoped and doped with 1 mol% $Tm_2O_3$. The $BaTiO_3$ ceramics doped with 1 mol% $Tm_2O_3$ had 40% higher dielectric constant (${\varepsilon}$ = 2700) than that of the undoped $BaTiO_3$ specimen at curie temperature and met X7R specification. According to the result of highly accelerated degradation test conducted at $150^{\circ}C$, 70 V, and 24 hr, the oxygen diffusion was declined in dielectrics doped with 1 mol% $Tm_2O_3$. The $Tm^{3+}$ ion substituted selectively Ba site and Ti site and contributed to the generation of the core-shell structure. Oxygen vacancies occurred by substitution for Ti site could reduce excess oxygen that reacted to the Ni electrode.

• Korean Journal of Remote Sensing
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• v.35 no.3
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• pp.471-482
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• 2019

The mission of the high-resolution camera for the lunar exploration is to provide 3D topographic information. It enables us to find the appropriate landing site or to control accurate landing by the short distance stereo image in real-time. In this paper, the ground verification and analysis system using the multi-application stereo camera to develop the high-resolution camera for the lunar exploration are proposed. The mission test items and test plans for the mission requirement are provided and the test results are analyzed by the ground verification and analysis system. For the realistic simulation for the lunar orbiter, the target area that has similar characteristics with the real lunar surface is chosen and the aircraft flight is planned to take image of the area. The DEM is extracted from the stereo image and compose three dimensional results. The high-resolution camera mission requirements for the lunar exploration are verified and the ground data analysis system is developed.

• International Journal of Contents
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• v.13 no.4
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• pp.23-28
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• 2017

Of the total economic loss caused by disasters, 40% are due to floods and floods have a severe impact on human health and life. So, it is important to monitor the water level of a river and to issue a flood warning during unfavorable circumstances. In this paper, we propose a modified error function to improve a hydrological modeling using a multi-layer perceptron (MLP) neural network. When MLP's are trained to minimize the conventional mean-squared error function, the prediction performance is poor because MLP's are highly tunned to training data. Our goal is achieved by preventing overspecialization to training data, which is the main reason for performance degradation for rare or test data. Based on the modified error function, an MLP is trained to predict the water level with rainfall data at upper reaches. Through simulations to predict the water level of Nakdong River near a UNESCO World Heritage Site "Hahoe Village," we verified that the prediction performance of MLP with the modified error function is superior to that with the conventional mean-squared error function, especially maximum error of 40.85cm vs. 55.51cm.