• Journal of Digital Convergence
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• v.10 no.9
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• pp.47-57
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• 2012

This study was conducted to investigate the pre-service teacher's perception of the possibility of using smartphones in the classroom, moreover, to confirm the policy related to using smartphones in schools. For the objectives, this study, firstly, investigated the pre-service teacher's awareness of having cellphones in the classroom, secondly, analyzed the pre-service teacher's opinion of using smartphones for educational objectives and elements for those investigated objectives, finally, investigated the school policy for educational objectives of using smartphones. The participants of this study were 146 pre-service teachers among three universities in Seoul. The results showed that the pre-service teachers opposed using cellphones in the classroom. Next, it was found that most of them had smartphones and they knew how to use them effectively. For the aspects of educational use of smartphones, they recognized that smartphones could be used as a smart educational tool, an efficient teaching and learning tool, and an assistant tool for teaching and learning. In order to use smartphones for the investigated educational tools, the learning contents, the ways of teaching and learning, and the technical support of the school should be prepared. Finally, the pre-service teachers thought that the school policy should be changed in order to use smartphones for educational objectives, and the school policy with regard to using smartphones in the classroom should be decided by the teachers. Most of all, for the educational use of smartphones, the pre-service teachers believed that the change of the students' perception was the most significant.

• Journal of the Korean Society of Clothing and Textiles
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• v.35 no.1
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• pp.104-114
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• 2011

There is rising interest in green energy, energy efficient equipment, and products as countries show increased interest in 'Low Carbon and Green Growth'. The cellphone has become one of the essential influences on modem people beyond the meaning itself by the release and the commercialization of the Smartphone. Thus, it considers that the introduction of fashion for cellphones and digital devices to be always on should be a quite natural design attempt for humans to wear clothes at all times. In addition, outdoor activities increase as the population enjoys more sports and leisure time that requires the development of specialized outwear such as the development of a functional jacket. This specialized field is associated with higher value-added businesses. This study made a prototype of a functional jacket equipped with solar cells that established a system of a fashion design that is harmonious with green growth as a plan to measure of fashion design for green growth. The objects of this study are as follow: First, the study seeks a design method for green growth. Second, it makes a prototype to present the improved design method. Third, it presents the establishment of a design system that considers green growth and the concrete measures practical for the system. It established the design system and made the prototype of functional jacket equipped with solar cells, LED, and digital devices as a measure of design for green growth based on the improvement plan of the design that the problems had been supplemented for. Previous studies were mainly about prototypes that attempted to equip mobile digital devices as a study of smart wear; however, this study leaves the issue of power supply for a follow-up study that is different from preceding studies.

• Journal of KIISE:Computer Systems and Theory
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• v.37 no.4
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• pp.195-204
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• 2010

Due to improved wireless communication technologies, it is possible to provide multimedia streaming service for mobile device clients like PDAs and cellphones. Wireless networks are serviced on low bandwidth channels and mobile devices work on limited hardware specifications. In these conditions, transcoding technologies are needed to adapt the media for streaming services to given mobile environments. To transcode from the source media to the target media for corresponding grades, transcoding servers perform transcoding jobs as exhausting their resources. Since various transcoding loads occur according to the target transconding grades, an effective transcoding load balancing policy is required among transcoding servers. In addition to transcoding process, servers should maintain QoS streams for mobile clients for total serviced times. It requires real-time requirements to support QoS for various mobile clients. In this paper, a new transcoding load distribution method is proposed. The proposed method can be driven for fair load balance between distributed transcoding servers. Based on estimated transcoding time, movie information and target transcoding bit-rate, it provides fair transcoding load distribution and also performs admission control to support QoS streams for mobile clients.

• Asian Journal for Public Opinion Research
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• v.5 no.2
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• pp.143-174
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• 2018

A cultural exchange program widens the horizons of students. It gives them the opportunity to associate with other societies and learn their cultures at the same time. This program also serves as a training ground where students enhance their skills, acquire learnings, and gain experiences that will help them in their future careers and make them more competitive than others. Hence, the objective of this study is to come up with an output from a set of guidelines established and gathered from the different "work and travel" experiences of the participants. This study adopted the phenomenological and was conducted in places that are relatively quiet for recording, and suitable and convenient for both the researchers and participants. The researchers gathered data through in-depth interviews of samples gathered through snowball sampling. Cellphones were used to record interviews. At the end of the thematic analysis of information, the researchers came up with three major categories which included: (1) 'having the opportunity to know the industry well and improve one's capability', 'undergoing different cultural exchange experiences for better development', and 'being able to practice intercultural immersion'. Some of the researchers' recommendations would be to institute a feedback mechanism such as personal interviews, monitoring visits, etc. and use the output, a set of guidelines, that would help the future 'work and travel' participants to prepare and anticipate the program they would undergo.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.3
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• pp.109-115
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• 2019

Most demand forecasting studies for telecommunication services have focused on estimating market size at the introductory stage of new products or services, or on suggesting improvement methods of forecasting models. Although such studies forecast business growth and market sizes through demand forecasting for new technologies and overall demands in markets, they have not suggested more specific information like relative market share, customers' preferences on technologies or service, and potential sales power. This study focuses on the telecommunication service industry and explores ways to calculate the relative market shares between competitors, considering competitive situations at the introductory stage of a new mobile telecommunication service provider. To reflect the competitive characteristics of the telecommunication markets, suggested is an extended conjoint analysis using service coverage and service switching rates as modification variables. This study is considered to be able to provide strategic implications to businesses offering existing service and ones planning to launch new services. The result of analysis shows that the new service provider has the greatest market share at the competitive situation where the new service covers the whole country, offers about 50% of existing service price, and allows all cellphones except a few while the existing service carrier maintains its price and service and has no response to the new service introduction. This means that the market share of the new service provider soars when it is highly competitive with fast network speed and low price.

• Journal of Intelligence and Information Systems
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• v.22 no.3
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• pp.129-142
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• 2016

Customer product reviews have become one of the important factors for purchase decision makings. Customers believe that reviews written by others who have already had an experience with the product offer more reliable information than that provided by sellers. However, there are too many products and reviews, the advantage of e-commerce can be overwhelmed by increasing search costs. Reading all of the reviews to find out the pros and cons of a certain product can be exhausting. To help users find the most useful information about products without much difficulty, e-commerce companies try to provide various ways for customers to write and rate product reviews. To assist potential customers, online stores have devised various ways to provide useful customer reviews. Different methods have been developed to classify and recommend useful reviews to customers, primarily using feedback provided by customers about the helpfulness of reviews. Most shopping websites provide customer reviews and offer the following information: the average preference of a product, the number of customers who have participated in preference voting, and preference distribution. Most information on the helpfulness of product reviews is collected through a voting system. Amazon.com asks customers whether a review on a certain product is helpful, and it places the most helpful favorable and the most helpful critical review at the top of the list of product reviews. Some companies also predict the usefulness of a review based on certain attributes including length, author(s), and the words used, publishing only reviews that are likely to be useful. Text mining approaches have been used for classifying useful reviews in advance. To apply a text mining approach based on all reviews for a product, we need to build a term-document matrix. We have to extract all words from reviews and build a matrix with the number of occurrences of a term in a review. Since there are many reviews, the size of term-document matrix is so large. It caused difficulties to apply text mining algorithms with the large term-document matrix. Thus, researchers need to delete some terms in terms of sparsity since sparse words have little effects on classifications or predictions. The purpose of this study is to suggest a better way of building term-document matrix by deleting useless terms for review classification. In this study, we propose neutrality index to select words to be deleted. Many words still appear in both classifications - useful and not useful - and these words have little or negative effects on classification performances. Thus, we defined these words as neutral terms and deleted neutral terms which are appeared in both classifications similarly. After deleting sparse words, we selected words to be deleted in terms of neutrality. We tested our approach with Amazon.com's review data from five different product categories: Cellphones & Accessories, Movies & TV program, Automotive, CDs & Vinyl, Clothing, Shoes & Jewelry. We used reviews which got greater than four votes by users and 60% of the ratio of useful votes among total votes is the threshold to classify useful and not-useful reviews. We randomly selected 1,500 useful reviews and 1,500 not-useful reviews for each product category. And then we applied Information Gain and Support Vector Machine algorithms to classify the reviews and compared the classification performances in terms of precision, recall, and F-measure. Though the performances vary according to product categories and data sets, deleting terms with sparsity and neutrality showed the best performances in terms of F-measure for the two classification algorithms. However, deleting terms with sparsity only showed the best performances in terms of Recall for Information Gain and using all terms showed the best performances in terms of precision for SVM. Thus, it needs to be careful for selecting term deleting methods and classification algorithms based on data sets.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.207-212
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• 2023

Near-infrared (NIR) absorbing dyes have been applied to various applications such as optical filters, biotechnology, energy storage and conversion, coating additive, and traditionally information-storage materials. Because image sensors used in cellphones and digital cameras have sensitivity in the NIR region, the NIR cut-off filter is essential to achieving more clear images. As energy storage and conversion have been important, diverse NIR absorbing materials have been developed to extend the absorption region to the NIR region, and NIR absorbing materials-based research has proceeded to improve device performances. Adding NIR-absorbing dye with a photo-thermal effect to a self-healable coating system has been attractive for future mobility technology, and more effective self-healing properties have been reported. In this report, the chemical structures of representative NIR-absorbing dyes and state of the art research based on NIR-absorbing dyes are introduced.