• Explosives and Blasting
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• v.30 no.2
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• pp.29-42
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• 2012

Variables influencing the free face movement due to rock blasting include the physical and mechanical properties, in particular the discontinuity characteristics, explosive type, charge weight, burden, blast-hole spacing, delay time between blast-holes or rows, stemming conditions. These variables also affects the blast vibration, air blast and size of fragmentation. For the design of surface blasting, the priority is given to the safety of nearby buildings. Therefore, blast vibration has to be controlled by analyzing the free face movement at the surface blasting sites and also blasting operation needs to be optimized to improve the fragmentation size. High-speed digital image analysis enables the analyses of the initial movement of free face of rock, stemming optimality, fragment trajectory, face movement direction and velocity as well as the optimal detonator initiation system. Even though The high-speed image analysis technique has been widely used in foreign countries, its applications can hardly be found in Korea. This thesis aims at carrying out a fundamental study for optimizing the blast design and evaluation using the high-speed digital image analysis. A series of experimentation were performed at two large surface blasting sites with the rock type of shale and granite, respectively. Emulsion and ANFO were the explosives used for the study. Based on the digital images analysis, displacement and velocity of the free face were scrutinized along with the analysis fragment size distribution. In addition, AUTODYN, 2-D FEM model, was applied to simulate detonation pressure, detonation velocity, response time for the initiation of the free face movement and face movement shape. The result show that regardless of the rock type, due to the displacement and the movement velocity have the maximum near the center of charged section the free face becomes curved like a bow. Compared with ANFO, the cases with Emulsion result in larger detonation pressure and velocity and faster reaction for the displacement initiation.

• Journal of the Korean GEO-environmental Society
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• v.15 no.1
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• pp.63-68
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• 2014

In this study, it was found that determined the photocatalytic degradation of antibiotics (lincomycin, LM) with various catalyst composite of titanium dioxide ($TiO_2$), hydroxyapatite (HAP) and germanium (Ge) under UV-A irradiation. At first, various type of complex catalysts were investigated to compare the enhanced photocatalytic potential. It was observed that in order to obtain the removal efficiencies were $TiO_2/HAP/Ge$ > $TiO_2/Ge$ > $TiO_2/HAP$. The composition of $TiO_2/HAP/Ge$ using a statistical approach based on mixture analysis design, one of response surface method was investigated. The independent variables of $TiO_2$ ($X_1$), HAP ($X_2$) and Ge ($X_3$) which consisted of 6 condition in each variables was set up to determine the effects on LM ($Y_1$) and TOC ($Y_2$) degradation. Regression analysis on analysis of variance (ANOVA) showed significant p-value (p < 0.05) and high coefficients for determination value ($R^2$ of $Y_1=99.28%$ and $R^2$ of $Y_2=98.91%$). Contour plot and response curve showed that the effects of $TiO_2/HAP/Ge$ composition for LM degradation under UV-A irradiation. And the estimated optimal composition for TOC removal ($Y_2$) were $X_1=0.6913$, $X_2=0.2313$ and $X_3=0.0756$ by coded value. By comparison with actual applications, the experimental results were found to be in good agreement with the model's predictions, with mean results for LM and TOC removal of 99.2% and 49.3%, respectively.

• Korean Journal of Microbiology
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• v.47 no.1
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• pp.92-96
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• 2011

Rhodococcus sp. strain DK17 possesses three megaplasmids (380 kb pDK1, 330 kb pDK2, and 750 kb pDK3). The alkylbenzene-degrading genes (akbABCDEF) are present on pDK2 while the phthalate operons which are duplicated are present on both pDK2 (ophA'B'C'R') and pDK3 (ophABCR). DK17 with an optimal temperature of $30^{\circ}C$ showed no growth at $37^{\circ}C$. When transferred to $30^{\circ}C$, however, the $37^{\circ}C$ culture began to grow immediately, indicating that $37^{\circ}C$ is not lethal but stressful for DK17 growth. In addition, when exposed to $37^{\circ}C$ even for a short time, a part of DK17 cells lost the ability to degrade o-xylene (a model compound of alkylbenzenes). When two hundred colonies were randomly selected for colony PCR for pDK2-specific akbC, ophC', or pDK3-specific ophC, a total of 29 colonies were found to have lost at least one of the three genes. PFGE analysis clearly showed that all the mutants have different megaplasmid profiles from that of DK17 wild type, which are divided into five different cases: Type I (10 mutants, pDK2 loss and acquisition of a new ~700 kb plasmid), Type II (9 mutants, pDK2 loss), Type III (8 mutants, pDK3 loss and acquisition of a new ~400 kb plasmid), Type IV (1 mutant, pDK3 loss), and Type V (1 mutant, pDK2 and pDK3 loss and acquisition of the ~400 kb and ~700 kb plasmids). The above results showing that growth temperature changes can induce physical changes in bacterial genomes suggest that environmental changes in habitats including temperature fluctuations affect significantly the evolution of bacteria.

• Economic and Environmental Geology
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• v.51 no.2
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• pp.87-97
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• 2018

The cesium (Cs) removal from the contaminated water system has been considered to be difficult because the cesium likes to exist as soluble phases such as ion and complexes than the solid in water system. Many researches have focused on developing the breakthrough adsorbent to increase the cesium removal efficiency in water. In this study, the laboratory scale experiments were performed to investigate the feasibility of the adsorption process using the bamboo charcoal for the Cs contaminated water system. The Cs removal efficiency of the bamboo charcoal were measured and the optimal adsorption conditions were determined by the adsorption batch experiments. Total 5 types of commercialized bamboo charcoals in Korea were used to identify their surface properties from SEM-EDS and XRD analyses and 3 types of bamboo charcoals having large specific surface areas were used for the adsorption batch experiment. The batch experiments to calculate the Cs removal efficiency were performed at conditions of various Cs concentration (0.01 - 10 mg/L), pH (3 - 11), temperature ($5-30^{\circ}C$), and adsorption time (10 - 120 min.). Experimental results were fitted to the Langmuir adsorption isotherm curve and their adsorption constants were determined to understand the adsorption properties of bamboo charcoal for Cs contaminated water system. From results of SEM-EDS analyses, the surfaces of bamboo charcoal particles were composed of typical fiber structures having various pores and dense lamella structures in supporting major adsorption spaces for Cs. From results of adsorption batch experiments, the Cs-133 removal efficiency of C type bamboo charcoal was the highest among those of 3 bamboo charcoal types and it was higher than 75 % (maximum of 82 %) even when the initial Cs concentration in water was lower than 1.0 mg/L, suggesting that the adsorption process using the bamboo charcoal has a great potential to remove Cs from the genuine Cs contaminated water, of which Cs concentration is low (< 1.0 mg/L) in general. The high Cs removal efficiency of bamboo charcoal was maintained in a relatively wide range of temperatures and pHs, supporting that the usage of the bamboo charcoal is feasible for various types of water. Experimental results were similar to the Langmuir adsorption model and the maximum amount of Cs adsorption (qm:mg/g) was 63.4 mg/g, which was higher than those of commercialized adsorbents used in previous studies. The surface coverage (${\theta}$) of bamboo charcoal was also maintained in low when the Cs concentration in water was < 1.0 mg/L, investigating that the Cs contaminated water can be remediated up with a small amount of bamboo charcoal.

• Korean Journal of Environmental Biology
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• v.36 no.1
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• pp.73-81
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• 2018

This study was conducted to understand the current status of the translocated species using a precede study and a model to evaluate the potential invasiveness that could adversely affect the aquatic ecosystem in the Gangneungnamdae Stream. A total of 12 translocated species were investigated and identified from 9 sites in a precede study, and steadily increased since 1982. For the study, which utilized research based on the total FISK (Fish Invasivenss Screening Kit) scores, all of the non-native fishes in Gangneungnamdae Stream were classified into two groups: namely as a high and a medium risk of becoming invasive. It was determined that there were two species (Zacco platypus and Pseudorasbora parva) that were determined to have posed the highest risk. The study determined that the mean scores were shown to have ranged from $3.06({\pm}0.16)-3.42({\pm}0.13)$. Consequently, the habitat analysis showed that the determined QHEI (Qualitative Habitat Evaluation Index) values in the stream averaged 146 (88-171), indicating that an optimal habitat condition did exist in that locale. It can be inferred that compared to land use in the surrounding watersheds, the QHEI values and frequency of translocated species showed the lower the altitude of stream, the QHEI values were decreased and in case of land use pattern, a noted decreased forest and grassland area, and gradually increased urbanized area was seen to exist in the region. The correlation between the fish assemblage, QHEI, land use pattern of surrounding watershed and number of translocated species was identified and analyzed when the stream altitude decreased, and the number of species was increased (r= - 0.782, p=0.0127), the number of species was decreased (r= - 0.737, p=0.0234), and finally when the QHEI values were decreased, it was noted that the urbanized area was increased (r=0.292, p=0.446). In the case of the number of translocated species, when the number of translocated species was increased, the associated urbanized area was increased.

• Applied Microscopy
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• v.35 no.1
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• pp.31-39
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• 2005

Synapses are contact points where one neuron communicates with another. The morphological change of synapses under various physiological or pathological conditions has long been hypothesized to modify their functional properties. 3-dimensional (3-D) reconstruction of synapses with serial ultrathin sections has contributed to the understanding of ultrastructural dimensions and compositions of synapses. The 3-D reconstruction procedures, however, require a great amount of expertise as well as include prohibitively timeconsuming processes. Here, we introduce efficient 3-D reconstruction technique using high-voltage electron microscopy (HVEM). Primarily, we established an optimal section thickness and staining condition to observe synaptic structures in detail under HVEM. The result showed that synaptic profiles were preserved at the section thickness of 250 nm without the overlapping of synaptic ultrastructures. An increase in the reaction time of en bloc staining was most efficient to enhance contrast than the extension of postembedding staining or the addition of uranyl acetate during dehydration. Then, 3-D reconstruction of parallel fiber-Purkinje cell synapses in the rat cerebellum was carried out with serial HVEM images and reconstruction software. The images were aligned and the contours of synapses were outlined on each section. 3-D synapses were finally extracted from the section files by grouping all the synaptic contours. The reconstructed synapse model clearly demonstrated the configuration of pre and postsynaptic components. These results suggest that 3-D reconstruction of synapses using HVEM is much efficient and suitable for massive quantitative studies on synaptic connectivity than conventional TEM approach using numerous ultrathin sections.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.3
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• pp.543-560
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• 2018

With the increased development in downtown underground space facilities that vertically cross under a railway at a shallow depth, the demand for non-open cut method is increasing. However, most construction sites still adopt the pipe roof method, where medium and large diameter steel pipes are pressed in to form a roof, enabling excavation of the inside space. Among the many factors that influence the loosening region and loads that occur while pressing in steel pipes, the size of the pipe has the largest impact, and this factor may correspond to the magnitude of load applied to the underground structure inside the steel pipe roof. The super equilibrium method (SEM) has been developed to minimize ground disturbance and loosening load, and uses small diameter pipes of approximately 114 mm instead of conventional medium and large diameter pipes. This small diameter steel pipe is called an SEM pile. After SEM piles are pressed in and the grouting reinforcement is constructed, a crossing structure is pressed in by using a hydraulic jack without ground subsidence or heaving. The SEM pile, which plays the role of timbering, is a fore-poling pile of approximately 5 m length that prevents ground collapse and supports surface load during excavation of toe part. The loosening region should be adequately calculated to estimate the spacing and construction length of the piles and stiffness of members. In this paper, we conducted a comparative analysis of calculations of loosening load that occurs during the press-in of SEM pile to obtain an optimal design of SEM. We analyzed the influence of factors in main theoretical and empirical formulas applied for calculating loosening regions, and carried out FEM analysis to see an appropriate loosening load to the SEM pile. In order to estimate the soil loosening caused by actual SEM-pile indentation and excavation, a steel pipe indentation reduction model test was conducted. Soil subsidence and soil loosening were investigated quantitatively according to soil/steel pipe (H/D).

• Journal of Distribution Science
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• v.8 no.3
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• pp.37-47
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• 2010

CRM refers to the operating activities that always maintain and promote good relationship with customers to ultimately maximize the company's profits by understanding the value of customers to meet their demands, establishing a strategy which may maximize the Life Time Value and successfully operating the business by integrating the customer management processes. In our country, many big businesses are introducing CRM initiatively to use it in marketing strategy however, most medium and small sized companies do not understand CRM clearly or they feel difficult to introduce it due to huge investment needed. This study is intended to present CRM promotion strategy and activities plan fit for the medium and small sized companies by analyzing the success factors of the leading companies those have already executed CRM by surveying the precedents to make the distributors out of the industries have close relation with consumers to overcome their weakness in scale and strengthen their competitiveness in such a rapidly changing and fiercely competing market. There are 5 stages to build CRM such as the recognition of the needs of CRM establishment, the establishment of CRM integrated database, the establishment of customer analysis and marketing strategy through data mining, the practical use of customer analysis through data mining and the implementation of response analysis and close loop process. Through the case study of leading companies, CRM is needed in types of businesses where the companies constantly contact their customers. To meet their needs, they assertively analyze their customer information. Through this, they develop their own CRM programs personalized for their customers to provide high quality service products. For customers helping them make profits, the VIP marketing strategy is conducted to keep the customers from breaking their relationships with the companies. Through continuous management, CRM should be executed. In other words, through customer segmentation, the profitability for the customers should be maximized. The maximization of the profitability for the customers is the key to CRM. These are the success factors of the CRM of the distributors in Korea. Firstly, the top management's will power for CS management is needed. Secondly, the culture across the company should be made to respect the customers. Thirdly, specialized customer management and CRM workers should be trained. Fourthly, CRM behaviors should be developed for the whole staff members. Fifthly, CRM should be carried out through systematic cooperation between related departments. To make use of the case study for CRM, the company should understand the customer and establish customer management programs to set the optimal CRM strategy and continuously pursue it according to a long-term plan. For this, according to collected information and customer data, customers should be segmented and the responsive customer system should be designed according to the differentiated strategy according to the class of the customers. In terms of the future CRM, integrated CRM is essential where the customer information gathers together in one place. As the degree of customers' expectation increases a lot, the effective way to meet the customers' expectation should be pursued. As the IT technology improved rapidly, RFID (Radio Frequency Identification) appears. On a real-time basis, information about products and customers is obtained massively in a very short time. A strategy for successful CRM promotion should be improving the organizations in charge of contacting customers, re-planning the customer management processes and establishing the integrated system with the marketing strategy to keep good relation with the customers according to a long-term plan and a proper method suitable to the market conditions and run a company-wide program. In addition, a CRM program should be continuously improved and complemented to meet the company's characteristics. Especially, a strategy for successful CRM for the medium and small sized distributors should be as follows. First, they should change their existing recognition in CRM and keep in-depth care for the customers. Second, they should benchmark the techniques of CRM from the leading companies and find out success points to use. Third, they should seek some methods best suited for their particular conditions by achieving the ideas combining their own strong points with marketing. Fourth, a CRM model should be developed that will promote relationship with individual customers just like the precedents of small sized businesses in Switzerland through small but noticeable events.

• Journal of Intelligence and Information Systems
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• v.26 no.1
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• pp.23-45
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• 2020

Big data is creating in a wide variety of fields such as medical care, manufacturing, logistics, sales site, SNS, and the dataset characteristics are also diverse. In order to secure the competitiveness of companies, it is necessary to improve decision-making capacity using a classification algorithm. However, most of them do not have sufficient knowledge on what kind of classification algorithm is appropriate for a specific problem area. In other words, determining which classification algorithm is appropriate depending on the characteristics of the dataset was has been a task that required expertise and effort. This is because the relationship between the characteristics of datasets (called meta-features) and the performance of classification algorithms has not been fully understood. Moreover, there has been little research on meta-features reflecting the characteristics of multi-class. Therefore, the purpose of this study is to empirically analyze whether meta-features of multi-class datasets have a significant effect on the performance of classification algorithms. In this study, meta-features of multi-class datasets were identified into two factors, (the data structure and the data complexity,) and seven representative meta-features were selected. Among those, we included the Herfindahl-Hirschman Index (HHI), originally a market concentration measurement index, in the meta-features to replace IR(Imbalanced Ratio). Also, we developed a new index called Reverse ReLU Silhouette Score into the meta-feature set. Among the UCI Machine Learning Repository data, six representative datasets (Balance Scale, PageBlocks, Car Evaluation, User Knowledge-Modeling, Wine Quality(red), Contraceptive Method Choice) were selected. The class of each dataset was classified by using the classification algorithms (KNN, Logistic Regression, Nave Bayes, Random Forest, and SVM) selected in the study. For each dataset, we applied 10-fold cross validation method. 10% to 100% oversampling method is applied for each fold and meta-features of the dataset is measured. The meta-features selected are HHI, Number of Classes, Number of Features, Entropy, Reverse ReLU Silhouette Score, Nonlinearity of Linear Classifier, Hub Score. F1-score was selected as the dependent variable. As a result, the results of this study showed that the six meta-features including Reverse ReLU Silhouette Score and HHI proposed in this study have a significant effect on the classification performance. (1) The meta-features HHI proposed in this study was significant in the classification performance. (2) The number of variables has a significant effect on the classification performance, unlike the number of classes, but it has a positive effect. (3) The number of classes has a negative effect on the performance of classification. (4) Entropy has a significant effect on the performance of classification. (5) The Reverse ReLU Silhouette Score also significantly affects the classification performance at a significant level of 0.01. (6) The nonlinearity of linear classifiers has a significant negative effect on classification performance. In addition, the results of the analysis by the classification algorithms were also consistent. In the regression analysis by classification algorithm, Naïve Bayes algorithm does not have a significant effect on the number of variables unlike other classification algorithms. This study has two theoretical contributions: (1) two new meta-features (HHI, Reverse ReLU Silhouette score) was proved to be significant. (2) The effects of data characteristics on the performance of classification were investigated using meta-features. The practical contribution points (1) can be utilized in the development of classification algorithm recommendation system according to the characteristics of datasets. (2) Many data scientists are often testing by adjusting the parameters of the algorithm to find the optimal algorithm for the situation because the characteristics of the data are different. In this process, excessive waste of resources occurs due to hardware, cost, time, and manpower. This study is expected to be useful for machine learning, data mining researchers, practitioners, and machine learning-based system developers. The composition of this study consists of introduction, related research, research model, experiment, conclusion and discussion.

• Korean Chemical Engineering Research
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• v.53 no.1
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• pp.31-38
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• 2015

At present, carbon dioxide ($CO_2$) emission, which causes global warming, is a major issue all over the world. To reduce $CO_2$ emission directly, commercial deployment of $CO_2$ separation processes has been attempted in industrial plants, such as power plant, oil refinery and steelmaking plant. Besides, several studies have been done on indirect reduction of $CO_2$ emission from recycle of reducing gas (carbon monoxide or hydrogen containing gas) in the plants. Unlike many competing gas separation technologies, pressure swing adsorption (PSA) and membrane filtration are commercially used together or individually to separate a single component from the gas mixture. However, there are few studies on operation of sequential separation process of multi-component gas which has more than two target gas products. In this paper, process simulation model is first developed for two available configurations: $CO_2$ PSA-CO PSA-$H_2$ PSA and $CO_2$ PSA-CO PSA-$H_2$ membrane. Operation optimization and economic evaluation of the processes are also performed. As a result, feed gas contains about 14% of $H_2$ should be used as fuel than separating $H_2$, and $CO_2$ separation should be separated earlier than CO separation when feed gas contains about 30% of $CO_2$ and CO. The simulation results can help us to find an optimal process configuration and operation condition for separation of multicomponent gas with $CO_2$, CO, $H_2$ and other gases.