• Journal of Korea Game Society
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• v.11 no.6
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• pp.13-22
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• 2011

In the digital media environment, the convergence is in the progress creating the new service and contents by users and developing the new needs of users by the service and contents as well. Social games are actualizing the new meaning of convergence. shows not only a new situation blurring the boundary of work and leisure, labor and playing and private and public sector, but how meaningful it is to make connection of social interactions and social assets a solid network. As the most popular social game text, reveals how the personal connections and personal networks constructs the social capital by making the ritual communication more interesting and flexible to the social gamers.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.288-288
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• 2013

Lithium-ion battery (LIB) is one of the most important rechargeable battery and portable energy storage for the electric digital devices. In particular, study about the higher energy capacity and longer cycle life is intensively studied because of applications in mobile electronics and electric vehicles. Generally, the LIB's capacity can be improved by replacing anode materials with high capacitance. The graphite, common anode materials, has a good cyclability but shows limitations of capacity (~374 mAh/g). On the contrary, silicon (Si) and germanium(Ge), which is same group elements, are promising candidate for high-performance LIB electrodes because it has a higher theoretical specific capacity. (Si:4200 mAh/g, Ge:1600 mAh/g) However, it is well known that Si volume change by 400% upon full lithiation (lithium insertion into Si), which result in a mechanical pulverization and poor capacity retention during cycling. Therefore, variety of nanostructure group IV elements, including nanoparticles, nanowires, and hollow nanospheres, can be promising solution about the critical issues associated with the large volume change. However, the fundamental research about correlation between the composition and structure for LIB anode is not studied yet. Herein, we successfully synthesized various structure of nanowire such as Si-Ge, Ge-Carbon and Si-graphene core-shell types and analyzed the properties of LIB. Nanowires (NWs) were grown on stainless steel substrates using Au catalyst via VLS (Vapor Liquid Solid) mechanism. And, core-shell NWs were grown by VS (Vapor-Solid) process on the surface of NWs. In order to characterize it, we used FE-SEM, HR-TEM, and Raman spectroscopy. We measured battery property of various nanostructures for checking the capacity and cyclability by cell-tester.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.5
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• pp.420-423
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• 2020

This study proposes an indirect constant voltage control algorithm for hybrid solid-state transformers (HSSTs) by using primary side information. Considering the structure of HSSTs, measuring voltage and current information on the primary side of a transformer is necessary to control the converter and inverter of the power converter. The secondary side output voltage is measured to apply the conventional secondary side constant voltage control algorithm, and thus, the digital control board requires the same rated insulation voltage as that of the transformer. To solve this problem, the secondary voltage of the transformer obtained from the tap voltage is used. Moreover, output voltage decreases as load increases because the proposed indirect constant voltage control scheme does not consider the cable impedance between the secondary output terminal and the load. This study also proposes a technique for compensating the secondary output voltage by using the primary current of the transformer and the resistance value of the cable. An experiment is conducted using a scale-down HSST prototype consisting of a 660 V/220 V tap transformer. The problem of the proposed indirect constant voltage control strategy and the improvement effect due to the application of the compensation method are compared using the derived experimental results.

• The Journal of Advanced Prosthodontics
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• v.15 no.3
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• pp.145-154
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• 2023

PURPOSE. The objective of this study was to investigate how internal structures influence the overall and marginal accuracy of full arch preparations fabricated through additive manufacturing in different printing systems. MATERIALS AND METHODS. A full-arch preparation digital model was set up with three internal designs, including solid, hollow, and grid. These were printed using three different resin printers with nine models in each group. After scanning, each data was imported into the 3D data processing software together with the master cast, aligned and trimmed, and then put into the 3D data analysis software again to compare the overall and marginal deviation whose results are expressed using root mean square values and color maps. To evaluate the trueness of the resin model, the test data and reference data were compared, and the precision was evaluated by comparing the test data sets. Color maps were observed for qualitative analysis. Data were statistically analyzed by one-way analysis of variance and Bonferroni method was used for post hoc comparison (α = .05). RESULTS. The influence of different internal structures on the accuracy of 3D printed resin models varied significantly (P < .05). Solid and grid models showed better accuracy, while the hollow model exhibited poor accuracy. The color maps show that the resin models have a tendency to shrink inwards. CONCLUSION. The internal structure design influences the accuracy of the 3D printing model, and the effect varies in different printing systems. Irrespective of the kind of printing system, the printing accuracy of hollow model was observed to be worse than those of solid and grid models.

• The Journal of Korean Institute for Practical Engineering Education
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• v.3 no.2
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• pp.83-92
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• 2011

The computer program for analysis of mechanical vibration has been developed using visual C++. This program is organized in a format similar to most standard texts on the mechanical vibration. This program consists of a number of menus to perform various calculations as well as a set of dedicated graphical user interfaces. Solutions to problems are given in both graphical and numerical forms. Numerical examples show the effectiveness and applicability of the program. This program can be utilized to analyze the vibration behavior of mechanical systems.

• Journal of Information Technology Applications and Management
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• v.22 no.2
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• pp.43-70
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• 2015

Concerns have been growing about whether domestic internet protocol television (IPTV) can establish a solid foothold in the pay TV market, largely because of the lack of IPTV-only content and service differentiation. It has been difficult for IPTV providers to attract valuable PPs (program providers) to strengthen their positions, and IPTV providers have invested much money into procuring content. To survive this difficult situation, IPTV providers need to reappraise their profit sharing methods and content distribution structure to facilitate the expansion of their subscriber base. This can be done by attracting valuable PPs to IPTV providers and securing extra revenue by distributing more content for their PP partners. The IPTV industry has a different structure and value chain from the digital cable industry. Moreover, profit sharing schemes among participants in the IPTV industry are complicated. Thus it is essential to analyze the criteria for profit sharing, the selection of attributes in profit sharing, and their cause-effect relationship in developing fair pricing for broadcast content in the IPTV industry. This study introduces the attributes that need to be considered for the pricing of content and profit sharing among IPTV providers and PPs. In addition, this study uses system dynamics to analyze the relationship among those attributes along with additional associated factors for the pricing of content.

• Korean Journal of Materials Research
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• v.30 no.11
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• pp.627-635
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• 2020

3D printing technology is a processing technology in which 3D structures are formed by fabricating multiple 2D layers of materials based on 3D designed digital data and stacking them layer by layer. Although layers are stacked using inkjet printing to release various materials, it is still rare for research to successfully form a product as an additive manufacture of multi-materials. In this study, dispersion conditions are optimized by adding a dispersant to an acrylic monomer suitable for inkjet printing using Co₃O₄ and Al₂O₃. 3D structures having continuous composition composed of a different ceramic material are manufactured by printing using two UV curable ceramic inks whose optimization is advanced. After the heat treatment, the produced structure is checked for the formation and color of the desired crystals by comparing the crystalline analysis according to the characteristics of each part of the structure with ceramic pigments made by solid phase synthesis method.

• Journal of Digital Convergence
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• v.19 no.2
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• pp.323-337
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• 2021

This study will attempt to analyze media art and discuss its main characteristics by using the concept based on Relational Aesthetics 'Affective Turn' as a basis of the theory. In addition, this study has some theoretical and practical implications, both in terms of the research and analysis of artworks and the structure development of art theories and aesthetics. To conduct the research, I have gone through a literature review on previous studies related to media art and Relational Aesthetics. Then, I have conducted a case study on the media art of TeamLab. This study shows that from the perspective of Relational Aesthetics, media art shows unique characteristics such as borderless and shareability. Moreover, it can allow the audience to actually 'feel' the relationship and integration between various objects. I hopethat this research could be used as a solid basis for future research and helpstrengthen the interaction between modern art and the public.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.4
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• pp.169-175
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• 2014

Digital ink-jet printing system has many advantages such as fast and fine printing of various images, high efficiency and low cost process. Generally digital ink-jet printing requires ceramic pigments of cyan, magenta, yellow and black with thermal and glaze stability above $1000^{\circ}C$ for the application of porcelain product design. In this study, pink-red colored $CaO-SnO_2-Cr_2O_3-SiO_2$ pigment was synthesized using solid state reaction. The synthesis conditions of $Ca(Cr,Sn)SiO_5$ pigment such as annealing temperature, amount of mineralizer and non-stoichiometric composition were optimized. Crystal structure and morphology of the obtained $Ca(Cr,Sn)SiO_5$ pigment were analyzed using XRD, SEM, PSA, FT-IR and effect of Cr substitution on the pigment color was analyzed using Uv-vis. spectrophotometer and CIE $L^*a^*b^*$ measurement.

• Journal of Digital Convergence
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• v.16 no.3
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• pp.429-438
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• 2018

Brad Bird, a screenwriter and animation director in the United States, criticized the situation in which most animations were produced and released for the children since the early 2000s. He said that animation is an art form capable of conveying messages not only to children but also to adults, and that their development potential is high. In this study, I analyzed overall components such as narrative structure, character, subplot, symbol, and foreshadow of Brad Bird's animated feature films , , and examined his narrative features and strategies. As a result, the narrative features of animation as an art form are as follows: First, conveying the message of a serious subject that will deeply sympathize with adults as well as children. Second, expressing the social agenda which criticizes the contradiction of the real world and the periodic mistakes. Third, solid narrative structure through a dense plot based on realistic situation setting. I hope that this study will be used as basic research material for various animation production in the future.