• Journal of the Korean Geographical Society
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• v.40 no.6 s.111
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• pp.653-670
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• 2005

The purpose of this study is to explore a spatial agglomeration characteristics and innovative milieu of the shoemaking industry in Seoul. In order to explain it, currently discussed dynamic agglomeration economies approach is applied and as an example, shoemaking industry in Seoul has been analyzed. The result of this research can be boardly summarized into two points. Frist, agglomeration economy is changing from urbanization economy to localization economy in this newly rising core of shoemaking industry which is Sung-Su dong area. Also, cooperative effects based on collective efficiency between companies and people are being generated within the area. This is largely affected by networking infrastructure between companies and people within the area, non-trade dependency and social capital acclamation. Secondly, the lack of institutional agglomeration formation in this area is considered to be the obstacle for the long-term development and innovation spin-off. This means recognition switch-over and institutional concern and support is needed in the future from the public sector.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.8
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• pp.1487-1493
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• 2016

The susceptible, exposed, infectious, and recovered model (SEIR) is used extensively in the field of epidemiology. On the other hand, dissemination information among users through internet grows exponentially. This information spreading can be modeled as an epidemic. In this paper, we derive the mathematical model of SEIR in viral communication from the view of optimal control theory. Overall the methods based on classical calculus, In order to solve the optimal control problem, proved to be more efficient and accurate. According to Pontryagin's minimum principle (PMP) the Hamiltonian function must be optimized by the control variables at all points along the solution trajectory. We present our method based on the PMP and forward backward algorithm. In this algorithm, one should integrate forward in time for the state equations then integrate backward in time for the adjoint equations resulting from the optimality conditions. The problem is mathematically analyzed and numerically solved as well.

• Journal of Information Science Theory and Practice
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• v.6 no.2
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• pp.46-61
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• 2018

The mobile social networking application Instagram is a well-known platform for sharing photos and videos. Since it is folksonomy-oriented, it provides the possibility for image indexing and knowledge representation through the assignment of hashtags to posted content. The purpose of this study is to analyze how Instagram users tag their pictures regarding different kinds of picture and hashtag categories. For such a content analysis, a distinction is made between Food, Pets, Selfies, Friends, Activity, Art, Fashion, Quotes (captioned photos), Landscape, and Architecture image categories as well as Content-relatedness (ofness, aboutness, and iconology), Emotiveness, Isness, Performativeness, Fakeness, "Insta"-Tags, and Sentences as hashtag categories. Altogether, 14,649 hashtags of 1,000 Instagram images were intellectually analyzed (100 pictures for each image category). Research questions are stated as follows: RQ1: Are there any differences in relative frequencies of hashtags in the picture categories? On average the number of hashtags per picture is 15. Lowest average values received the categories Selfie (average 10.9 tags per picture) and Friends (average 11.7 tags per picture); for highest, the categories Pet (average 18.6 tags), Fashion (average 17.6 tags), and Landscape (average 16.8 tags). RQ2: Given a picture category, what is the distribution of hashtag categories; and given a hashtag category, what is the distribution of picture categories? 60.20% of all hashtags were classified into the category Content-relatedness. Categories Emotiveness (about 4.38%) and Sentences (0.99%) were less often frequent. RQ3: Is there any association between image categories and hashtag categories? A statistically significant association between hashtag categories and image categories on Instagram exists, as a chi-square test of independence shows. This study enables a first broad overview on the tagging behavior of Instagram users and is not limited to a specific hashtag or picture motive, like previous studies.

• Journal of the Korean association of regional geographers
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• v.18 no.2
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• pp.188-202
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• 2012

The purpose of this study is to review a good sample for a healthy city to adapt its strategy. People has interested in the urban environment and their health in the region with a step-up in income and the improvement of living conditions. They has realized that urban environment is closely related to their quality of life, concentrated on development of clean city and healthy city from the point of urban planning. The movement of healthy city has been spread out from Europe on 1986, and WHO(World Health Organization) has been supporting the practical work to improve upon the physical or social condition on each regional level. The policy of healthy city has promoted centering around each local government which is made up of networking with others globally to interchange informations. This study reviewed a successful case of Kobe city in detail and will provide further useful insights into planners in building appropriate policies.

• Korean Journal of Community Nutrition
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• v.22 no.2
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• pp.115-126
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• 2017

Objectives: The purpose of the study was to develop communication strategies for effective nutrition education targeting pregnant women and to create nutrition education contents. Methods: The format and the contents of online resources on nutrition information for pregnant women provided by reliable institutions were analyzed. Possible solutions to overcome barriers of nutrition education as well as communication strategies for effective nutrition education were identified by a brainstorming process. Based on the communication strategies, contents for nutrition education were created. Understandability, level of interest, applicability to daily life, harmony of text and illustration, and overall satisfaction of the contents were evaluated by dietitians and pregnant women. Results: The four communication strategies were developed; (1) to focus on a few important messages, (2) to provide evidence-based information, (3) to create illustrations or infographics with a minimum amount of text, and (4) to provide tips on how to improve the current diet options. Based on these strategies, the contents were focused on three important nutrients for pregnant women, folate, iron, and calcium. The percentages of the recommended nutrient intakes of the three nutrients on selected menu and its improved version by adding a dish or changing a dish into another dish were calculated and provided. Finally, the contents were delivered as illustrations with a minimum amount of text. Overall, dietitians and pregnant women were satisfied with the contents. Conclusions: The contents developed in this study can be used in a pamphlet or a pregnancy diary, or can be shared in social networking services. Further contents on other nutrients and various menu are expected to be developed using these communication strategies.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.11
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• pp.3916-3936
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• 2014

Smartphone applications like games, image processing, e-commerce and social networking are gaining exponential growth, with the ubiquity of cellular services. This demands increased computational power and storage from mobile devices with a sufficiently high bandwidth for mobile internet service. But mobile nodes are highly constrained in the processing and storage, along with the battery power, which further restrains their dependability. Adopting the unlimited storage and computing power offered by cloud servers, it is possible to overcome and turn these issues into a favorable opportunity for the growth of mobile cloud computing. As the mobile internet data traffic is predicted to grow at the rate of around 65 percent yearly, even advanced services like 3G and 4G for mobile communication will fail to accommodate such exponential growth of data. On the other hand, developers extend popular applications with high end graphics leading to smart phones, manufactured with multicore processors and graphics processing units making them unaffordable. Therefore, to address the need of resource constrained mobile nodes and bandwidth constrained cellular networks, the computations can be migrated to resourceful servers connected to cloud. The server now acts as a bridge that should enable the participating mobile nodes to offload their computations through Wi-Fi directly to the virtualized server. Our proposed model enables an on-demand service offloading with a decision support system that identifies the capabilities of the client's hardware and software resources in judging the requirements for offloading. Further, the node's location, context and security capabilities are estimated to facilitate adaptive migration.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2008.10b
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• pp.218-234
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• 2008

중국은 2008년 현재 메신저 이용자 수와 블로그 등의 웹 2.0 이용자 수에 있어서 세계 1위이다. 그리고 중국의 2007년 850억 달러의 인터넷 디지털 시장은 2015년에 2640억 달러로 성장할 전망이다. 이와 같이 인터넷 시장의 규모와 성장 가능성으로 인해 중국 인터넷 비즈니스의 중요성이 높아지고 있다. 이러한 필요성에 따라서 본 연구에서는 중국의 인터넷 동향 중에서 가장 큰 주목을 끌고 있는 웹 2.0 기반의 사회 연결망 서비스 분야에서 다음 세 가지의 연구 질문을 설정하고 그 답을 찾아보았다. 첫째, 중국 사회 연결망 서비스의 주요 특징은 무엇인가? 이러한 질문에 답하기 위해 본 연구에서는 문헌연구를 바탕으로 중국의 대표적인 사회 연결망 서비스 업체로 Tencent QQ와 Sina Poco를 살펴보았고, 중국 사회 연결망 서비스 이용자의 가입 이유, 갱신 이유, 주요 내용, 유상 서비스에 대한 태도 등을 살펴보았으며, 중국 인터넷 사용자의 집단별 특징에 대해 살펴보았다. 둘째, 중국 사회 연결망 서비스의 이용에 영향을 미치는 주요 요인들은 무엇인가? 이러한 질문에 답하기 위해 동기부여이론, TAM 이론. 관련 선행연구 등을 검토하여 중국 사회 연결망 서비스의 이용에 영향을 미치는 요인들로서 사용자 참여, 사회적 영향, 네트워크 효과, 유용성, 시스템 품질 등을 도출하였고 PLS를 이용한 데이터 분석을 통해 검증하였다. 검증결과, 사회 연결망 서비스 이용에 유용성이 가장 큰 영향을 미치고, 다음으로 네트워크 효과, 사용자 참여, 시스템 품질 순으로 유의한 영향을 미치는 것으로 나타났다. 반면, 사회적 영향은 유의하지 않은 것으로 나타났다. 셋째, 중국과 한국은 어떠한 점에서 차이가 있는가? 가장 두드러진 차이는 사회적 영향에 있어서 한국은 유의 적인데 비해 중국이 유의적이지 않다는 점이다. 이는 한국과 중국 사이에 국가 문화적 차이가 존재하기 때문에 발생했다고 생각할 수도 있고, 중국이 인터넷 성장기에 있는데 비해 한국은 인터넷 성숙기에 있는 등의 기술적, 사회적, 경제적 발달 과정상의 차이에 의한 것이라고도 볼 수 있다.

• Journal of the Korea Safety Management & Science
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• v.14 no.3
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• pp.101-109
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• 2012

It is commonly recognized that railway is one of the representative transportation and it offers public service based on strategies for being rapid, automation, safety. Since the opening of high speed railway, 3-hundred-million people have used it and acknowledged its efficiency. However, derailed accident at Kwangmyeong station in February, 2011, frequent malfunction of KTX-Sancheon, and accidents by engineer's careless fault damaged on credibility of safety, Especially, spreaded accidents through social networking service by cell phones amplified anxiety of public, being criticized by the press. This study analyzed statistics of past accident and cases of passing-by accident, and surveyed 152 KTX captain engineers about their recognition of the accident by careless fault and experiences of possibility of occurrence for preventing engineer's careless fault and restoring trust According to the analysis, engineers worry about responsibility and disadvantages related to the accidents for the most, and they are nervous about malfunction for the second most. This study presents prevention methods regarding the result. First, it is required to improve mental stability and concentration on their work, secondly, advanced ability to cope with malfunction or error through repetitive education and training are required to increase confidence, and for the last, improvement of operational supporting system such as ATP, GPS to prevent errors by human factors. Improvement of the system is expected to lead engineers to prevent careless fault and regain the reputation of railway.

• Journal of Digital Convergence
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• v.9 no.5
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• pp.225-233
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• 2011

Internet telephony is an Internet service which supports voice telephone using VoIP technology on the IP-based Internet. It has some advantages in that voice telephone services can be accompanied with multimedia services such as video communication and messaging services. Recently, the introduction of smart phones has led to a growth in social networking services and thus, the research and development of Internet telephony has been actively progressed and has the potential to become a replacement for the telephone service that is currently being used. In this paper we designed and implemented a recording system which records voice data of SIP-based Internet telephone's voice calls. It is developed on the linux system and has some features such as audio mixing of two in/out voice channels, live packet sniffing, and the ability to transfer mixed audio files to the log file server. These functions are implemented using various open source softwares. Afterwards, this VoIP recording system will be applied as a base technology to advanced services like a VoIP-based call center system.

• Journal of Digital Convergence
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• v.14 no.3
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• pp.165-170
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• 2016

The purpose of this study was to explore the differences in sentiment on social networking sites among six languages (English, German, Russian, Spanish, Turkish and Dutch). A total of 204 million tweets were collected using Streaming API. Subjective/objective ratio, sentiment strength, positive/negative ratio, number of retweets and boundary impermeability were analyzed with SentiStrength to estimate the trends of emotional expression via Twitter. The results showed that subjective/objective ratio and the positive/negative ratio of tweets were significantly different by languages (p<0.001). And, there were significant effects of language on sentiment strength, boundary impermeability and the number of retweets (p<0.001). The results also indicate that the cross-cultural, language differences should be taken into account in sentiment analysis on SNS.