• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.233-242
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• 2013

Cyanobacteria (blue-green algae) are not only the first oxygenic organisms on earth but also the foremost primary producers in aquatic environment. Massive growth of cyanobacteria, in eutrophic waters, usually changes the water colour to green and is called as algal (cyanobacterial) bloom or green tide. Cyanobacterial blooms are a result of high levels of primary production by certain species such as Microcystis sp., Anabaena sp., Oscillatoria sp., Aphanizomenon sp. and Phormidium sp. These cyanobacterial species can produce hepatotoxins or neurotoxins as well as malodorous compounds like geosmin and 2-methylisoborneol (MIB). In order to solve the nationwide problem of hazardous cyanobacterial blooms in Korea, the following technically and strategically sound approaches need to be developed. 1) As a long-term strategy, reduction of the nutrients such as phosphorus and nitrogen in our water bodies to below permitted levels. 2) As a short term strategy, field application of combination of already established bloom remediation techniques. 3) Development of emerging convergence technologies based on information and communication technology (ICT), environmental technology (ET) and biotechnology (BT). 4) Finally, strengthening education and creating awareness among students, public and industry for effective reduction of pollution discharge. Considering their ecological roles, a complete elimination of cyanobacteria is not desirable. Hence a holistic approach mentioned above in combination to addressing the issue from a social perspective with cooperation from public, government, industry, academic and research institutions is more pragmatic and desirable management strategy.

• International Journal of Automotive Technology
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• v.6 no.2
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• pp.149-159
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• 2005

A full nonlinear finite element P185/70Rl4 passenger car radial-ply tire model was developed and run on a 1.7-meter-diameter spinning test drum/cleat model at a constant speed of 50 km/h in order to investigate the tire transient response characteristics, i.e. the tire in-plane free vibration modes transmissibility. The virtual tire/drum finite element model was constructed and tested using the nonlinear finite element analysis software, PAM-SHOCK, a nonlinear finite element analysis code. The tire model was constructed in extreme detail with three-dimensional solid, layered membrane, and beam finite elements, incorporating over 18,000 nodes and 24 different types of materials. The reaction forces of the tire axle in vertical (Z axis) and longitudinal (X axis) directions were recorded when the tire rolled over a cleat on the drum, and then the FFT algorithm was applied to examine the transient response information in the frequency domain. The result showed that this PI 85/70Rl4 tire has clear peaks of 84 and 45 Hz transmissibility in the vertical and longitudinal directions. This result was validated against more than 10 previous studies by either theoretical or experimental approaches and showed excellent agreement. The tire's post-impact response was also investigated to verify the numerical convergence and computational stability of this FEA tire model and simulation strategy, the extraordinarily stable scenario was confirmed. The tire in-plane free vibration modes transmissibility was successfully detected. This approach was never before attempted in investigations of tire in-plane free vibration modes transmission phenomena; this work is believed to be the first of its kind.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.3
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• pp.401-406
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• 2011

In order to solve a complex optimization problem more efficiently than traditional approaches, various meta-heuristic algorithms such as genetic algorithm, ant-colony algorithm, and harmony search algorithm have been extensively researched. Compared with other meta-heuristic algorithm, harmony search algorithm shows a better result to resolve the complex optimization issues. Harmony search algorithm is inspired by the improvision process of musician for most suitable harmony. In general, the performance of harmony search algorithm is determined by the value of harmony memory considering rate, and pitch adjust rate. In this paper, modified harmony search algorithm is proposed in order to derive best harmony. If the optimal solution of a specific problem can not be found for a certain period of time, a part of original harmony memory is updated as the selected suitable harmonies. Experimental results using test function demonstrate that the updated harmony memory can induce the approximation of reliable optimal solution in the short iteration, because of a few change of fitness.

• Journal of Digital Convergence
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• v.17 no.6
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• pp.349-354
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• 2019

The purpose of this study is to measure and analyze color image scale when viewing the public objects installed in Kongju National University and the installation environment, and preferred colors and color image scale in the color planning. The research was conducted with the analysis of the sculpture installed in the school and the questionnaire for the students. As a result of the study, suggestions were made for points to be considered for user's perception of environmental sculptures in the school and when constructing the sculpture. This study approaches the color of the public environment sculpture installed in the school academically, and proposes factors to be considered in the color planning stage in the future. Therefore, it is expected that this study will provide appropriate guidelines for the installation and planning of the sculpture in the school.

• Journal of Digital Convergence
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• v.17 no.6
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• pp.77-91
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• 2019

In order to establish a sales strategy for convenience store lunches, this study conducted analysis using association rules based on POS data obtained from convenience stores located in four commercial districts. For this purpose, the data used in the analysis were divided into the time zones from 6:00 am to 8:00 pm, 17:00 pm to 19:00 pm, and the convenience stores according to the commercial areas. As a result of the analysis, it was found that products that were sold together with a lunch box were mainly made of products that could be eaten together with lunch such as milk, beverage, and cotton. However, it was confirmed that there were differences in the types and numbers of the products that were sold together with the lunch boxes of the morning time and the afternoon hours for the other products. These results and approaches are expected to contribute to finding and responding to the needs for goods and services that change as well as convenience stores as well as sociocultural changes.

• Journal of the Korean Electrochemical Society
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• v.22 no.2
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• pp.60-68
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• 2019

High-voltage operation of the lithium ion battery is one of the advantageous approaches to obtain high energy capacity without changing the conventional cell components and structure. However, operating at harsh condition inevitably results in severe side reactions at the electrode surface and structural disintegration of active material particles. Herein we coated layers composed of $Al_2O_3$ and ZnO on the electrode based on NCM using atomic layer deposition (ALD). Thicker layers of novel Al-doped ZnO (AZO) coating compared to conventional ALD coated layers are prepared. Cathode based on NCM with the varying AZO coating thickness are fabricated and used for coin cell assembly. Effect of ALD coating thickness on the charge-discharge cycle behavior obtained at high-voltage operation was investigated.

• Membrane Journal
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• v.31 no.5
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• pp.293-303
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• 2021

Separation membranes used in water filtration, protein purification or biomedical filtration device frequently undergo membrane fouling for several reasons. The formation of biofilm on the membrane surface by bacteria causes a severe problem for durability of the membrane. For the protein separation, the membrane pores get blocked due to surface hydrophobicity of the membrane. There are several approaches controlling the membrane fouling and one of them is the incorporation of silver nanoparticles. Antibacterial properties of silver nanoparticles are well known and thus widely used in several applications. In this review, we have focused on the membranes where silver nanoparticles or its derivatives are either incorporated in the active layer of thin film composite membranes or uniformly distributed throughout the whole membranes.

• Journal of Korean Society for Quality Management
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• v.49 no.2
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• pp.145-159
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• 2021

Purpose: A statistical similarity evaluation to compare pharmacokinetics(PK) profile data between nonclinical and clinical experiments has become a significant issue on many drug development processes. This study proposes a new similarity index by considering important parameters, such as the area under the curve(AUC) and the time-series profile of various PK data. Methods: In this study, a new profile similarity index(PSI) by using the concept of a process capability index(Cp) is proposed in order to investigate the most similar animal PK profile compared to the target(i.e., Human PK profile). The proposed PSI can be calculated geometric and arithmetic means of all short term similarity indices at all time points on time-series both animal and human PK data. Designed simulation approaches are demonstrated for a verification purpose. Results: Two different simulation studies are conducted by considering three variances(i.e., small, medium, and large variances) as well as three different characteristic types(smaller the better, larger the better, nominal the best). By using the proposed PSI, the most similar animal PK profile compare to the target human PK profile can be obtained in the simulation studies. In addition, a case study represents differentiated results compare to existing simple statistical analysis methods(i.e., root mean squared error and quality loss). Conclusion: The proposed PSI can effectively estimate the level of similarity between animal, human PK profiles. By using these PSI results, we can reduce the number of animal experiments because we only focus on the significant animal representing a high PSI value.

• Journal of Industrial Convergence
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• v.19 no.5
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• pp.111-118
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• 2021

This study was conducted to examine the academic stress, menstrual attitude, and dysmenorrhea of adolescents and to understand their effects on dysmenorrhea. The subjects of the study were high school girls and 131 people who agreed to participate in the study were analyzed. Correlation analysis shows that the more negative the person is about menstruation, the more severe the physical symptoms, the more active the action, and the greater the emotional change, the more severe the person experienced dysmenorrhea. Factors affecting dysmenorrhea in adolescents were physical symptoms and positive acceptance among menstrual attitudes, and 68.8 percent explained the variable. In conclusion, considering the positive acceptance of menstruation and physical symptoms of adolescents, it is necessary to develop educational programs that provide integrated knowledge to manage dysmenorrhea in school health, and further individual and multidimensional approaches such as emotional support programs for negatively experienced emotions.

• Journal of Digital Convergence
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• v.19 no.2
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• pp.83-92
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• 2021

Recently many organizations have adopted 'untact' work due to social distancing caused by Coronavirus-19. To clarify some controversy about the effectiveness from 'untact' work, it is necessary to examine the cognition of organizational members. This study identified issues in 'untact' work from the literature review, analyzed the content of in-depth interviews with workers and managers experiencing 'untact' work, and compared both groups' cognition by applying the co-orientation model. Both groups pointed out the communication difficulty as the top disadvantage and showed no significant differences in job satisfaction, organizational commitment, and work-life balance. However, the two groups showed significant differences in their cognition about performance evaluation (agreement and workers' congruence) and productivity enhancement (workers' accuracy). This paper has an academic contribution in that it has focused on cognitive gaps between workers and managers, urges organizations to devise ways to reduce the gaps, and suggests future studies with quantitative approaches.