• Journal of Korean Society of Environmental Engineers
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• v.35 no.3
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• pp.179-191
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• 2013

This study was conducted to comparatively assess quantitative indicating factor for biomineralization characterizing $CO_2$ mineralization on three type of minerals (i.e., $CaCl_2$, $MgCl_2$, $CaCl_2-MgCl_2$) in an aqueous solution amended with Bacillus pasteurii or indigenous microorganisms for a S landfill cover soil. For given three types of minerals, $NH_4{^+}$ (urease activity) was released at the highest of 88 mg/L for $MgCl_2$, then 85 mg/L for $CaCl_2$, and the lowest of 42 mg/L for $CaCl_2-MgCl_2$. $CO_2$ gas in the head space was completely removed after 12, 12, and 24 hr for $CaCl_2$, $MgCl_2$ and $CaCl_2-MgCl_2$, respectively. $Ca^{2+}$ concentration in $CaCl_2$ solution was the quickest and the greatest decreased 92% for 12 hr whereas that in $CaCl_2-MgCl_2$ solution was lower at 85% for 36 hr. $Mg^{2+}$ concentration in $MgCl_2$ was more efficiently decreased at 46% for 48 hr than that of $CaCl_2-MgCl_2$ solution of 38.5% for 72 hr. Regardless of types of minerals or their concentration, pH was changed from 5.5 to 9 by biomineralization being progressed. Microbial activity ($OD_{600}$) was also changed from 0 to 0.6. SEM images indicated that spheroidal and trapezoid shape crystal were formed, which were identified as of $CaCO_3$ (Calcite) and $MgCO_3$ (Magnesite) by X-ray diffraction. In the long run, $NH_4{^+}$ (urease activity), $CO_2$ gas, $OD_{600}$, pH, $Ca^{2+}$ and $Mg^{2+}$ would be suitable for reasonable indicating factor in order to assess the degree of biomineralization efficiency.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.11
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• pp.613-625
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• 2017

For two agricultural reservoirs that are rented for fishing spots, benthic nutrient fluxes experiment were performed two times with two sediments from fishing-effective zone and one sediment from fishing-ineffective zone using laboratory core incubation in oxic and anoxic conditions. During benthic nutrient fluxes experiment, the changes in DO, EC, pH, and ORP in the supernatant were not significantly different between fishing-effective zone and fishing-ineffective zone, and were similar to the sediment-hypolimnetic diffused boundary layer in agricultural reservoir. Except for $NO_3{^-}-N$, more benthic nutrient fluxes of $NH_4{^+}-N$, T-P, and $PO{_4}^{3-}-P$ from sediment to hypolimnetic was measured in anoxic than in oxic conditions (p<0.05). As the DO concentration in hypolimnetic decreases, the microorganism-mediated ammonification is promoted, the nitrification is suppressed, and finally the $NH_4{^+}-N$ diffuses out from sediment to hypolimnetic. Also, the diffusion of T-P and $PO{_4}^{3-}-P$ from sediments to hypolimnetic is accelerated through the dissociation of the phosphorus bound to both organic matters and metal hydroxides. The difference in the benthic nutrient diffusive fluxes between fishing-effective zone and fishing-ineffective zone was not statistically significant (p>0.05). Therefore, it was found that fishing activities did not increase the benthic nutrient diffusive fluxes to a statistically significant level. Due to the short fishing activities of 10 years and the rate-limited diffusion of the laboratory core incubation, the contribution of fishing activities on sediment pollution is estimated to be low. No significant correlation was found between the total amount of nutrients in sediment and the benthic nutrient diffusive fluxes in both aerobic and anaerobic conditions. Therefore, nutrients input from various nonpoint sources of watersheds are considered to be a more dominant factor rather than fishing activities in water quality deterioration, and both aeration and water circulation in hypolimnetic were required to suppress the anoxic environment in agricultural reservoirs.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.3
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• pp.1-8
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• 2007

PDiabetic neuropathy is one of the most common diabetes related complications including diabetic nephropathy and retinopahty. In clinical practices, nerve conduction velocity (NCV) has been used as a standard method for diagnosing diabetic neuropathy. However, it applies maximum current of 100mA to nerves causing stress and pain to patients. In this study, as a non-invasive method, $TcpO_2$ was utilized to investigate the difference and relationship between $TcpO_2$ and $SpO_2$ of normal and diabetic neuropathy subjects. In addition, a new method of diagnosing diabetic neuropathy using $TcpO_2$ is suggested. 50 normal subjects and 50 diabetic patients with neuropathy diagnosed by NCV participated in this study. Parameters used in this study were $TcpO_2$, $TcpCO_2$, and $SpO_2$. As a result of the $TcpO_2$ measurements, statistical significances were found from $TcpO_2$ of hands and feet from normal and patients group(p<0.01). $SpO_2$ measured from index finger of normal and patient groups showed no statistical significance(p>0.05). On the other hand, $SpO_2$ measured from great toes of normal and patient groups showed statistical significance(p<0.01). Correlation coefficient between $SpO_2$ of finger and $TcpO_2$ of hand was 0.400 (p<0.01) and $SpO_2$ of toe and $TcpO_2$ of foot was 0.471(p<0.01). Both correlation values were statistically significant. Sensitivities and specificities of the $TcpO_2$ method were found to be 66 % and 92 %, respectively. If the suggested $TcpO_2$ method is used periodically, prevention and early diagnosis of diabetic neuropathy would be possible.

• Geotechnical Engineering
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• v.11 no.2
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• pp.29-36
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• 1995

Load testis are executed on model reticulated root piles (RRP) to figure out the optimum slanting angle in the piles installation. One set of model RRP consists of 8 slanting piles which are installed in circular patterns forming two concentric circles, each of which is made by 4 piles. Each pile which is a steel bar of 5m in diameter and 300mm in length is coated to become a pile of 6.5mm in diameter. The slanting angle of the model RRP varies from 0$^{\circ}$ to 20$^{\circ}$ Comparing ultimate bearing capacities of the model RRP of different installation angles, it is observed that the ultimate capacities of the RRP increase as the installation angle increases until 15$^{\circ}$, and the optimum slanting angle of the RRP is around 15$^{\circ}$ The ultimate bearing capacity of the 15$^{\circ}$-RRP is found to be 22% bigger than that of the vertical RRP and 120% bigger than that of the circular surface footing whose diameter is same with the circle formed by outer root piles'heads. However, it is noticed that when the slanting angle of the RRP is increased over 15$^{\circ}$, the ultimate capacity starts to be reduced. The ultimate capacity of 20$^{\circ}$-RRP is even smaller than that of the vertical RRP by as much as 5%. From the observation of the load settlement curve obtained during the RRP load tests, it is known that as the slanting angle gets bigger the load -settlement behavior becomes more ductile.

• Journal of Intelligence and Information Systems
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• v.20 no.2
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• pp.149-162
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• 2014

Course guidance is a mentoring process which is performed before students register for coming classes. The course guidance plays a very important role to students in checking degree audits of students and mentoring classes which will be taken in coming semester. Also, it is intimately involved with a graduation assessment or a completion of ABEEK certification. Currently, course guidance is manually performed by some advisers at most of universities in Korea because they have no electronic systems for the course guidance. By the lack of the systems, the advisers should analyze each degree audit of students and curriculum information of their own departments. This process often causes the human error during the course guidance process due to the complexity of the process. The electronic system thus is essential to avoid the human error for the course guidance. If the relation data model-based system is applied to the mentoring process, then the problems in manual way can be solved. However, the relational data model-based systems have some limitations. Curriculums of a department and certification systems can be changed depending on a new policy of a university or surrounding environments. If the curriculums and the systems are changed, a scheme of the existing system should be changed in accordance with the variations. It is also not sufficient to provide semantic search due to the difficulty of extracting semantic relationships between subjects. In this paper, we model a course mentoring ontology based on the analysis of a curriculum of computer science department, a structure of degree audit, and ABEEK certification. Ontology-based course guidance system is also proposed to overcome the limitation of the existing methods and to provide the effectiveness of course mentoring process for both of advisors and students. In the proposed system, all data of the system consists of ontology instances. To create ontology instances, ontology population module is developed by using JENA framework which is for building semantic web and linked data applications. In the ontology population module, the mapping rules to connect parts of degree audit to certain parts of course mentoring ontology are designed. All ontology instances are generated based on degree audits of students who participate in course mentoring test. The generated instances are saved to JENA TDB as a triple repository after an inference process using JENA inference engine. A user interface for course guidance is implemented by using Java and JENA framework. Once a advisor or a student input student's information such as student name and student number at an information request form in user interface, the proposed system provides mentoring results based on a degree audit of current student and rules to check scores for each part of a curriculum such as special cultural subject, major subject, and MSC subject containing math and basic science. Recall and precision are used to evaluate the performance of the proposed system. The recall is used to check that the proposed system retrieves all relevant subjects. The precision is used to check whether the retrieved subjects are relevant to the mentoring results. An officer of computer science department attends the verification on the results derived from the proposed system. Experimental results using real data of the participating students show that the proposed course guidance system based on course mentoring ontology provides correct course mentoring results to students at all times. Advisors can also reduce their time cost to analyze a degree audit of corresponding student and to calculate each score for the each part. As a result, the proposed system based on ontology techniques solves the difficulty of mentoring methods in manual way and the proposed system derive correct mentoring results as human conduct.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.9
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• pp.441-450
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• 2016

In this study, we investigate the effect of the level of cognitive affordance which explains an explicit interaction method on the interest of viewers. Viewer's recognition of the interaction method is associated with cognitive affordance as a matter of visual-perceptual exposure of the input device and viewer's cognition of it. The final goal of the research on affordance is to enhance the audience participation rather than the smooth interation. Many interactive media artworks have been designed with hiding the explicit explanation to the artwork due to worry that the explicit explanation may also hinder the induction of impressions leading the viewer to an aesthetic experience and the retainment of interest. In this context, we set up two hypotheses for study on cognitive affordance. First, the more explicit the explanation of interaction method is, the higher the viewer' understanding of interaction method is. Second, the more explicit the explanation of interaction method is, the lower the interest of the viewer is. An interactive media art work was manufactured with three versions which vary in the degree of visual-perceptual information suggestion and we analyzed the participation and interest level of audience in each version. As a result of the experiments, the version with high explicitness of interaction was found to have long time spent on watching and high participation and interest of viewers. On the contrary, the version with an unexplicit interaction method was found to have low interest and satisfaction of viewers. Therefore, regarding usability, the hypothesis that a more explicit explanation of interaction would lower the curiosity and interest in exploration of the viewer was dismissed. It was confirmed that improvement of cognitive affordance raised the interaction of the work of art and interest of the viewer in the proposed interactive content. This study implies that interactive media art work should be designed in view of that the interaction and interest of audience can be lowered when cognitive affordance is low.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.5
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• pp.50-60
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• 2010

For the last half a century, the personal computer and software industries have been prosperous due to the incessant evolution of computer systems. In the 21st century, the embedded system market has greatly increased as the market shifted to the mobile gadget field. While a lot of multimedia gadgets such as mobile phone, navigation system, PMP, etc. are pouring into the market, most industrial control systems still rely on 8-bit micro-controllers and simple application software techniques. Unfortunately, the technological barrier which requires additional investment and higher quality manpower to overcome, and the business risks which come from the uncertainty of the market growth and the competitiveness of the resulting products have prevented the companies in the industry from taking advantage of such fancy technologies. However, high performance, low-power and low-cost hardware and software platforms will enable their high-technology products to be developed and recognized by potential clients in the future. This paper presents such a platform for industrial embedded systems. The platform was designed based on Telechips TCC8300 multimedia processor which embedded a variety of parallel hardware for the implementation of multimedia functions. And open-source Embedded Linux, TinyX and GTK+ are used for implementation of GUI to minimize technology costs. In order to estimate the expected performance and power consumption, the performance improvement and the power consumption due to each of enabled hardware sub-systems including YUV2RGB frame converter are measured. An analytic model was devised to check the feasibility of a new application and trade off its performance and power consumption. The validity of the model has been confirmed by implementing a real target system. The cost can be further mitigated by using the hardware parts which are being used for mass production products mostly in the cell-phone market.

• Journal of the Korean Geotechnical Society
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• v.29 no.9
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• pp.5-15
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• 2013

In this paper, the unsaturated slope stability analysis considering suction stress (Lu and Godt, 2008) was introduced and the results applied for a certain sand slope were analyzed. The unsaturated slope stability analysis considering suction stress can analyze both conditions of steady infiltration and no infiltration, and it can estimate the safety factor of slope as a function of soil depth. Also, the influence of weathering phenomenon at a certain depth from the ground surface can be considered. The stability analysis considering suction stress was applied to the unsaturated infinite slope composed of sand with the relative density of 60%. The suction stress under no infiltration condition was affected by ground water table until a certain influencing depth. However, the suction stress under steady infiltration condition was affected by seepage throughout the soils. Especially, the maximum suction stress was displayed around ground surface. The factor of safety in the infinite slope under no infiltration condition rapidly increased and decreased within the influence zone of ground water table. As a result of slope stability analysis, the factor of safety is less than 1 at the depth of 2.4 m below the ground surface. It means that the probability of slope failure is too high within the range of depths. The factor of safety under steady infiltration condition is greater than that under no infiltration condition due to the change of suction stress induced by seepage. As the steady infiltration rate of precipitation was getting closer to the saturated hydraulic conductivity, the factor of safety decreased. In case of the steady infiltration rate of precipitation with $-1.8{\times}10^{-3}cm/s$, the factor of safety is less than 1 at the depths between 0.2 m and 3 m below the ground surface. It means that the probability of slope failure is too high within the range of depths, and type of slope failure is likely to be shallow landslides.

• The Journal of Engineering Geology
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• v.14 no.1
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• pp.29-46
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• 2004

It is important to identify geometries of fracture that act as a conduit of fluid flow for characterization of ground water flow in fractured rock. Fracture geometries control hydraulic conductivity and stream lines in a rock mass. However, we have difficulties to acquire whole geometric data of fractures in a field scale because of discontinuous distribution of outcrops and impossibility of continuous collecting of subsurface data. Therefore, it is needed to develop a method to describe whole feature of a target fracture geometry. This study suggests a new approach to develop a method to characterize on the whole feature of a target fracture geometry based on the Fourier transform. After sampling of specimens along a target fracture from borehole cores, effective frequencies among roughness components were selected by the Fourier transform on each specimen. Then, the selected effective frequencies were averaged on each frequency. Because the averaged spectrum includes all the frequency profiles of each specimen, it shows the representative components of the fracture roughness of the target fracture. The inverse Fourier transform is conducted to reconstruct an averaged whole roughness feature after low pass filtering. The reconstructed roughness feature also shows the representative roughness of the target subsurface fracture including the geometrical characteristics of each specimen. It also means that overall roughness feature by scaling up of a fracture. In order to identify the characteristics of permeability coefficients along the target fracture, fracture models were constructed based on the reconstructed roughness feature. The computation of permeability coefficient was performed by the homogenization analysis that can calculate accurate permeability coefficients with full consideration of fracture geometry. The results show a range between $10^{-4}{\;}and{\;}10^{-3}{\;}cm/sec$, indicating reasonable values of permeability coefficient along a large fracture. This approach will be effectively applied to the analysis of permeability characteristics along a large fracture as well as identification of the whole feature of a fracture in a field scale.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.11
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• pp.1213-1221
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• 2006

In this study, granular sludge used in an anaerobic process treating brewery waste was inoculated in a laboratory scale of reactor to induce anaerobic ammonium oxidation(ANAMMOX). The reactor was operated with synthetic wastewater, which prepared at 1:1 ratio of $NH_4^+-N$ over $NO_2^--N$. Changes in nitrogen concentration, COD, alkalinity and gas production were analyzed. There are 3 phases of spanning in experimental period according to influent nitrogen concentration. In the Phase 1, each of the concentration of $NH_4^+-N$ and $NO_2^--N$ were increased from 1.91 $gN/m^3{\cdot}d$ to 14.29 $gN/m^3{\cdot}d$. Ammonium nitrogen loading(same as nitrite nitrogen) was 23.81 $gN/m^3{\cdot}d$ in the Phase 2 and 19.05 $gN/m^3{\cdot}d$ in the Phase 3, respectively $NO_2^--N$ has been removed up to 99% during whole period while the removal efficiency of $NH_4^+-N$ was significantly varied. In Phase 2, $NH_4^+-N$ was removed up to 75%. Microorganisms varied temporally through three phases were characterized by 16s rDNA analysis methods. ANAMMOX bacteria were dominantly found in phase 2 when the removal rate of $NO_2^--N$and $NH_4^+-N$ was the highest up to 99% and 75%, respectively. Due to erroneous exposed to air, the removal efficiency of $NH_4^+-N$ was unexpectedly lowered, but ANAMMOX bacteria still existed.