• Journal of the Microelectronics and Packaging Society
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• v.15 no.3
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• pp.27-33
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• 2008

With increasing use of portable appliances such as PDA and cellular phone, changing environment of applications requires higher solder joint reliability. The ENIG (Electroless Nickel Immersion Gold) process has been widely used for fine pitch SMT (Surface Mount Technology) and BGA (Ball Grid Array) packaged devices due to its benefits including excellent solderability, high uniformity and substantial legibility throughout the packaging process. Its brittle fracture of solder, however, has received increasingly attentions. It was Down that fracture brittleness is mainly related with black pad resulting from galvanic nickel corrosion and P-enriched layer formation between the IMC (Intermetallic Compounds) and electroless nickel layer. Theoretically, smooth electroless Ni layer was blown to have a advantages in minimizing the black pad phenomenon by uniform solution exchange during immersion gold plating. Nevertheless, how to control the surface morphology of electroless Ni layer has been hardly blown. This study investigates an effect of surface morphology of Cu underlayer on surface morphology of electroless Ni layer. To obtain various kinds of surface morphology of Cu layer, two types of Cu etching chemical and a number of Cu etching treatment were applied.

• Journal of The Korean Association For Science Education
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• v.40 no.2
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• pp.203-216
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• 2020

The purpose of this study is to explore the effects of a VR(virtual reality)-based biology class on both the cognitive and affective domains by developing and applying a VR-based biology program for 6th-grade elementary school students. For this research, we developed a VR teaching material about 'digestion' reflecting virtual reality characteristics and one hundred five students in an elementary school in an urban area participated in this study and took three VR-based lessons. To examine the cognitive effects of a VR-based biology class, the study subjects were divided into two groups. The experimental group was composed of 50 individuals who participated in VR-based biology lessons, while 55 students of a control group learned through general lessons. We collected data using drawing tasks for measuring students' modeling performance level from these groups and analyzed the cognitive effect of VR-based instruction. We also recorded 21 interviews of students after the intervention, which were transcribed to verify the students' perception of cognitive and affective effects. The key results are as follows: First, we demonstrated the possibility of applying a VR program reflecting VR characteristics (manipulation, multi-sensory, and interaction). Second, we found out that a VR-based biology class significantly enhances higher levels of thinking (spatial, abstract, and reflective thinking). Third, we examined students' perceptions on this program and came to the conclusion that VR characteristics positively affected cognitive and affective domains. This study may be able to contribute to offering guidelines on how to apply VR-programs to future science education effectively.

• Archives of design research
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• v.16 no.3
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• pp.309-318
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• 2003

A work of Art is not supposed to be isolated from the world, but it should be influenced by its cultural background and situations of the times. Therefore, Art itself reflects its era. In other words, it is created being based on the thought of its artist and simultaneously interacting with external conditions or circumstances of the era, so it would also affect the cultural code of its society. This is why modern art made by the individual living in this complicated and diversified society is quite avant-garde. Various demands from its society and diversified senses have been influencing diversification of works of Art. Now we can say that a mode of art is also dose to current stream of the times. A lot of artists have been trying to get out of traditional way of presentation techniques and classification of genres. In that point, the emergence of Multimedia Alt is inevitable in this digital era. The terms of Internet or multimedia are now familiar with everybody in the world, and a lot of works like Technology Art, Information Art, Computer Art, Digital Art, New Media Art, and so on have been coming into the world by using multimedia. Unlike other works of Art, these works from multimedia are practically used by being combined with technologies. Hereupon, in this paper I would like to find out a concept of Multimedia Art, its social function, and the future prospect of this brand-new form of art.

• School Mathematics
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• v.10 no.1
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• pp.23-42
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• 2008

The purpose of this study was to describe characteristics of thinking in elementary gifted students' solutions to algebraic tasks. Especially, this paper was focused on the students' strategies to develop generalization while problem solving, the justifications on the generalization and metacognitive thinking emerged in stildents' problem solving process. To find these issues, a case study was conducted. The subjects of this study were four 6th graders in elementary school-they were all receiving education for the gifted in an academy for the gifted attached to a university. Major findings of this study are as follows: First, during the process of the task solving, the students varied in their use of generalization strategies and utilized more than one generalization strategy, and the students also moved from one strategy toward other strategies, trying to reach generalization. In addition, there are some differences of appling the same type of strategy between students. In a case of reaching a generalization, students were asked to justify their generalization. Students' justification types were different in level. However, there were some potential abilities that lead to higher level although students' justification level was in empirical step. Second, the students utilized their various knowledges to solve the challengeable and difficult tasks. Some knowledges helped students, on the contrary some knowledges made students struggled. Specially, metacognitive knowledges of task were noticeably. Metacognitive skills; 'monitoring', 'evaluating', 'control' were emerged at any time. These metacognitive skills played a key role in their task solving process, led to students justify their generalization, made students keep their task solving process by changing and adjusting their strategies.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.5
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• pp.325-332
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• 2014

Growing concerns about harmful influence of radon on human body, many efforts are being made to decrease indoor radon concentration in advanced countries. To develop an indoor radon reduction technology, it is necessary to develop a technology to predict and evaluate indoor inflow and emission of radon. In line with that, the present study performed computational modelling of indoor dispersion of radon emitted from building materials. The computational model was validated by comparing computational results with analytical results. This study employed CFD (Computational Fluid Dynamics) analysis to evaluate the radon concentration and the airflow characteristics. Air change rate and ventilation condition were changed and several building materials having different radon emission characteristics were considered. From the results, the indoor radon concentration was high at flow recirculation zones and inversely proportional to the air change rate. For the different building materials, the indoor radon concentration was found to be highest in cement bricks, followed by eco-carats and plaster boards in the order. The findings from this study will be used as a method for selecting building materials and predicting and evaluating the amount of indoor radon in order to reduce indoor radon.

• The Journal of the Korea Contents Association
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• v.16 no.5
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• pp.180-193
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• 2016

The purpose of this study was to identify the utilization of school health room and the health problems among elementary and secondary school students as years go by sex, school locations, and to analyze the frequency and difficulty of nursing interventions performance that school health teachers was available to resolve students' health problems at school health room. Participants were fifty nine school health teachers with more than 3 years of career. As the years go by, utilization of school health room has gradually increased. Utilization of female than male was higher than 200%, i.e. Elementary school girls in urban area were the highest rate, and secondary school boys in urban area were the lowest. In male, utilization of school health room was in order the skin and subcutaneous, musculoskeletal, and digestive problems, and also was in order the skin and subcutaneous, digestive, and musculoskeletal problems in female. Utilization of in urban elementary school was higher on patricular health problem than in suburban areas. Nursing interventions of most often using were self-care management & education and counselling. Nursing intervention was the highest degree of difficulty in self-harm, seizure, circulatory health problems. In conclusions, utilization of school health room has gradually increased; therefore workload of school health teacher aggravated. To perform a heath teacher to effectively operate the general and emergency health issues, the expansion of qualified school health teachers is needed, and the standardized guidelines and refresher training programs is required.

• Journal of Digital Convergence
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• v.15 no.10
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• pp.429-436
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• 2017

A design thinking-based collaborative workshop in which various stakeholders in the milk processing industry circulation ecosystem participated shows a new problem innovation paradigm that encourages the spread of practical prototyping culture. in the expression of empathy and collective intelligence among members on facing issues, the conversion of collaboration and communication methods, the business handling of the organization based on the design work method as 'creativity mechanism'. In this workshop, which was promoted in three stages of 'approach to problems', 're-definition of problems', and 'experience-based future vision design', participants themselves redefine real problems in terms of the accuracy of feed orders between feed suppliers and livestock farmers, ordering of feeds on time, cost reduction of feed supply and present new alternatives and expanded business areas. The results suggested in this workshop suggest the usefulness of design thinking in business innovation in that they presented how to approach the problem and a creative thinking system to find its solution to direct and indirect stakeholders of the industry as well as the improvement of supply and demand rate of livestock feed and quality.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.5
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• pp.39-54
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• 2018

This study aims to expand K-Wave business. For this, it firstly investigated previous studies and pointed out limitations of the current scope of the K-Wave business. Therefore, as a theoretical background, it attempts to construct an analysis framework based on four types of creativity type model and to redefine the concept of K-Wave business, which refers to a series of business activities that create, utilize the asset, and reuse the originality of intellectual property assets. This study analyzes the business activities of K-Wave's asset creation, utilization, and talent linkage during 2013~2017. The scope of the asset creation covers the highest ranked movies, dramas, and K-pops, while the utilization of those is analyzed in cosmetics, food, and fashion industries. The personal talent is the source of new K-Wave value creation and Webtoon IP is analyzed. As a result, in the case of movies and dramas, the representative market is China, which is the result of the efforts to avoid the continuation of China's regulation and the development of local OTTs. It is confirmed that the product development for Chinese consumers is active as activities of K-Wave utilization in cosmetics, food and fashion. Interesting is that new K-Wave content is circulated in the beauty sector. Finally, it is confirmed that Webtoon IP, which has been structured with a solid story in individual talent, is the origin of new K-Wave asset creation such as movies and dramas.

• Journal of IKEEE
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• v.23 no.4
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• pp.1440-1447
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• 2019

Currently, the prevalence of autism spectrum disorders in children is reported to be higher and shows various types of disorders. In particular, they are having difficulty in communication due to communication impairment in the area of social communication and need to be improved through training. Thus, this study proposes a method of acquiring voice information through a microphone mounted on a robot designed through preliminary research and using this information to make intelligent motions. An ANN(Artificial Neural Network) was used to classify the speech data into robot motions, and we tried to improve the accuracy by combining the Recurrent Neural Network based on Convolutional Neural Network. The preprocessing of input speech data was analyzed using MFCC(Mel-Frequency Cepstral Coefficient), and the motion of the robot was estimated using various data normalization and neural network optimization techniques. In addition, the designed ANN showed a high accuracy by conducting an experiment comparing the accuracy with the existing architecture and the method of human intervention. In order to design robot motions with higher accuracy in the future and to apply them in the treatment and education environment of children with autism.

• Journal of the Korean Electrochemical Society
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• v.11 no.4
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• pp.284-288
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• 2008

Sn-thin film as high capacitive anode for thin film lithium-ion battery was prepared by organic-electrolyte electroplating using Sn(II) acetate. Electrolytic solution including $Li^+$ and $Sn^{2+}$ had 3 reduction peaks at cyclic voltammogram. Current peak at $2.0{\sim}2.5\;V$ region correspond to the electroplating of Sn on Ni substrate. This potential value is lower than 2.91 V vs. $Li^+/Li^{\circ}$, of the standard reduction potential of $Sn^{2+}$ under aqueous media. It is the result of high overpotential caused by high resistive organic electrolytic solution and low $Sn^{2+}$ concentration. Physical and electrochemical properties were evaluated using by XRD, FE-SEM, cyclic voltammogram and galvanostatic charge-discharge test. Crystallinity of electroplated Sn-anode on a Ni substrate could be increased through heat treatment at $150^{\circ}C$ for 2 h. Cyclic voltammogram shows reversible electrochemical reaction of reduction(alloying) and oxidation(de-alloying) at 0.25 V and 0.75 V, respectively. Thickness of Sn-thin film, which was calculated based on electrochemical capacity, was $7.35{\mu}m$. And reversible capacity of this cell was $400{\mu}Ah/cm^2$.