• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.10a
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• pp.133-164
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• 2005

Mobile games have emerged as the most innovative entertainment technology, adding new revenue streams, taking advantage of the potential of wireless applications and service offerings. Mobile games, like any other types of computer game, offer a unique value for users in providing an exciting digital experience in virtual worlds. Players can become empowered through the development of new characters and strategies within games to achieve rewarding successes against the computers and other players. The overall trend for mobile games is towards bigger, more colorful, more involving and exciting contents, which will build upon the developing capabilities of mobile phones and networks in order to bring new styles, concepts and experiences of game play to the users. In this paper, we attempt to investigate the demographic factors which play critical roles in determining the level of playing times; classify mobile gamers based on their motives for playing games; and empirically test differences in their demographic factors and mobile game usage. Statistical results show that significant differences in playing times exist, depending upon their age, gender, mobile device, mobile phone usage, mobile game experiences, and preferred games genres. Applying Factor analysis, we have identified Escape, Social interaction, Challenge and Competition, Fantasy, Diversion and Relaxation, Ease of Accessibility as key motivators for playing mobile games. Additional cluster analysis shows that the categorization of gamers, according to their usage habits and the key motivators for playing, can be made as follows: M-gamers, Multi-gamers and Communication-focused gamers. Further correlation of these grouping with socio-economic data shows the significant differences in gaming habits and patterns of mobile phone use.

• Microbiology and Biotechnology Letters
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• v.32 no.1
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• pp.16-21
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• 2004

Six bacterial strains which formed large halo on chitosan-containing agar plate were isolated from beach mud and crabs at South coast of Korean peninsula. They were designated as Bacillus cereus KNUC51, B. cereus KNUC52, B. cereus KNUC53, B. cereus KNUC54, B. cereus KNUC55, and Paenibacillus favisporus KNUC56 by analysing their morphologies and 16S rDNA sequences. Chitosanase activities of all isolates were similar to that of B. subtilis 168. To enhance the activity of chitosanase, a powerful mutagen, MNNG was treated for P favisporus KNUC56. Three mutants showed higher activity of chitosanase than that of the original strain. The DNA fragments containing chitosanase gene from B. cereus sources were cloned, sequenced, and their deduced amino acid sequence analysis showed over 93% homologies with that of the known B. cereus ATCC14579. Extracellular sample from the isolates was incubated in proper reaction mixture including chitosan for 5 minutes at $37^{\circ}C$ to produce 3-10 chitosan oligomers which has been known to be active for clinical agents and agronomical agents.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1188-1192
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• 2003

Chitinase producing bacteria, Arthrobacter nicotianae CH4 and A. nicotianae CH13, were isolated from small crabs by an enrichment culture using chitin as the sole carbon source. Crude chitinases from the two isolated strains, A. nicotianae CH4 and A. nicotianae CH13, were stable in the pH range of $3.0{\sim}9.0$ and in the temperature range of $20{\sim}60^{\circ}C$. The reducing sugar $(GlcNAc)_1$, or $(GlcNAc)_4$, corresponding to over 98% of the enzyme reaction products, was obtained. The production of functional $(GlcNAc)_1$ and $(GlcNAc)_4$ from A. nicotianae CH13 and A. nicotianae CH4, respectively, from the chitinases was useful. The chitinase system of A. nicotianae CH13 was supposed to be endo- and exo-chitinase, and N-acetylglucosaminidase.

• Journal of Food Hygiene and Safety
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• v.28 no.2
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• pp.124-129
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• 2013

The method for detection foods containing allergenic materials by PCR was developed in this study. To detect allergenic raw material from processed food, species specific primer which up to 200bp for PCR product were designed or selected from advanced research. As target materials, 14 items were selected (12 target materials for allergen in Korea, 2 target materials for allergen in foreign countries). The amplicon size for eggs, milk, buckwheat, peanuts, beans, wheat, mackerel, crab, shrimp, pork, peach, tomato, almond, and sesame were confirmed 281, 131, 138, 120, 118, 127, 211, 174, 231, 138, 174, 132, 103, and 220bp, respectively. And any non-specific bands were not detected among each others. Detection method for allergenic material developed in this study could be used to investigate inaccurate goods for allergen labeling or non-intentional contaminant during processed foods manufacturing. In addition, the system will be usefully to detection accurate allergenic raw materials of export for other countries.

• Research in Plant Disease
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• v.12 no.2
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• pp.139-143
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• 2006

Virion captured reverse transcription polymerase chain reaction (VC/RT-PCR) could detect plant virus quickly and accurately. In the VC/RT-PCR, no antibody is needed unlike immuno-captured RT-PCR (IC/RT-PCR) which had been improved method of RT-PCR for plant viruses, and virus nucleic acids can be obtained easily within 30minutes by property of polypropylene PCR tube which is hold and immobilized viral particles on its surface. For the virion capture of Tomato spotted wilt virus (TSWV), the extraction buffer was tested. The optimum macerating buffer for TSWV was 0.01M potassium phosphate buffer, pH 7.0, containing 0.5% sodium sulfite. The viral crude sap was incubated for 30 min at $4^{\circ}C$. The virions in the PCR tubes were washed two times with 0.01M PBS containing 0.05% Tween-20. The washed virions were treated at $95^{\circ}C$ immediately for 1 min containing RNase free water and chilled quickly in the ice. Disclosed virions' RNAs by heat treatment were used for RT-PCR. Dilution end point of $10^{-5}$ from plant's crude sap infected with TSWV showed relatively higher detection sensitivity for VC/RT-PCR. During multiple detection using two or more primers, interference was arisen by interactions between primer-primer and plant species. The result of multiplex RT-PCR was influenced by combinations of primers and the kind of plant, and the optimum extraction buffer for the multiplex detection by VC/RT-PCR should be developed.

• Journal of Plant Biotechnology
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• v.44 no.1
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• pp.97-106
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• 2017

Living modified crops are genetically modified living organisms and are widely used in biotechnical research and desired goods. As the reliance on LM products, concerns about safety of LMOs have been continuously increased in South Korea. We established the detection methods for unintentional released LMOs in environmental conditions. To detect six LM event genes of 1 canola, 1 maize and 4 soybeans, PCR conditions were based upon consideration of the Joint Research Centre information. Genomic DNAs were isolated from LM samples and PCR analysis were performed using each event-specific primer pair. Event-specific genes of all events were efficiently recognized by our methods. To investigate the insertion site of LM genes in each genome, we verified PCR product sequence by DNA sequencing. These results suggest that the LM event-specific gene amplification can be efficiently developed. In addition, our detection method is fit for monitoring and post-management of LM crops in the environment.

• Journal of the Korea Convergence Society
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• v.9 no.5
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• pp.33-41
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• 2018

The purpose of this study is to develop more accurate and robust emotion prediction neural network (EPNN) model by combining heart rate variability (HRV) and neural network. For the sake of improving the prediction performance more reliably, the proposed EPNN model is based on various types of activation functions like hyperbolic tangent, linear, and Gaussian functions, all of which are embedded in hidden nodes to improve its performance. In order to verify the validity of the proposed EPNN model, a number of HRV metrics were calculated from 20 valid and qualified participants whose emotions were induced by using money game. To add more rigor to the experiment, the participants' valence and arousal were checked and used as output node of the EPNN. The experiment results reveal that the F-Measure for Valence and Arousal is 80% and 95%, respectively, proving that the EPNN yields very robust and well-balanced performance. The EPNN performance was compared with competing models like neural network, logistic regression, support vector machine, and random forest. The EPNN was more accurate and reliable than those of the competing models. The results of this study can be effectively applied to many types of wearable computing devices when ubiquitous digital health environment becomes feasible and permeating into our everyday lives.

• The Journal of Industrial Distribution & Business
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• v.9 no.4
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• pp.63-72
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• 2018

Purpose - The purpose of this paper is to investigate the effects of online game properties, social interaction, and player satisfaction on intention to online games in Chinese gamers. Research design, data, and methodology - This study is an empirical analysis assuming that properties of online games, social interaction and satisfaction will induce Chinese gamers' intention to play online games. We set the relationship between the six variables as follows. First, the properties of online games, exogenous variables, were identified by three factors: entertainment, security, participation and challenge. Second, we had input social interaction among gamers as another exogenous variables. Third, the gamer's satisfaction of online games was added to the research model as a mediating variable between exogenous variables and endogenous variables. Finally, gamer's intention to play influenced by satisfaction and social interaction was used as final endogenous variable. The data used for the empirical analysis were collected through questionnaires for Chinese under age 35 who enjoy the online games. The data used in the research were finally extracted from 195 questionnaires. The collected data were tested through the analysis of the measurement model (Step 1) and the analysis of the structural model (Step 2). The covariance structure equation model (SEM) was used for the analysis. The measurement model and structural model were evaluated by the maximum likelihood method. Results - The results of the empirical analysis are as follows. The satisfaction of online games were entertainment and security had a significant effect to satisfaction; but participation and challenge and social interaction had no significant effect on satisfaction. The social interaction among gamers and the satisfaction with online games have a significant influence on the intention to play online games. As a result, the attributes of the game were affecting the intention to play the game after satisfaction. Social interaction influenced the intention to play online games rather than satisfaction itself. Conclusions - This study provide some practical implications for the new companies who want to enter the online game industry and seek to competitiveness in China, and provide theoretical implications on the role of interaction among gamers in the study of online games.