• KIPS Transactions on Software and Data Engineering
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• v.6 no.7
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• pp.371-378
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• 2017

Recently, with the spread of smart device and the introduction of web services, the data is rapidly increasing online, and it is utilized in various fields. In particular, the emergence of social media in the big data field has led to a rapid increase in the amount of unstructured data. In order to extract meaningful information from such unstructured data, interest in big data technology has increased in various fields. Big data is becoming a key resource in many areas. Big data's prospects for the future are positive, but concerns about data breaches and privacy are constantly being addressed. On this subject of big data, where positive and negative views coexist, the research of analyzing people's opinions currently lack. In this study, we compared the changes in peoples perception on big data based on unstructured data collected from the social media using a text mining. As a results, yearly keywords for domestic big data, declining positive opinions, and increasing negative opinions were observed. Based on these results, we could predict the flow of domestic big data.

• Journal of Internet Computing and Services
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• v.15 no.6
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• pp.107-115
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• 2014

Recently, increased use of the internet resulted in generation of large and diverse types of data due to increased use of social media, expansion of a convergence of among industries, use of the various smart device. We are facing difficulties to manage and analyze the data using previous data processing techniques since the volume of the data is huge, form of the data varies and evolves rapidly. In other words, we need to study a new approach to solve such problems. Many approaches are being studied on this issue, and we are describing an effective design and development to build indexing engine of big data platform. Our goal is to build a system that could effectively manage for huge data set which exceeds previous data processing range, and that could reduce data analysis time. We used large SNMP log data for an experiment, and tried to reduce data analysis time through the fast indexing and searching approach. Also, we expect our approach could help analyzing the user data through visualization of the analyzed data expression.

• Journal of Science Education
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• v.41 no.2
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• pp.248-266
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• 2017

The purpose of this study is to present various examples of collaborative learning based on the Instruction of Internet in the 6th grade elementary school mathematics class. So we introduce the design method of classroom environment for classroom Internet and give example of various teaching methods. This study was conducted for nine months from March to November, 2016, one sixth grade of elementary school in D area. During this period, we conducted Instruction of Internet-based collaborative learning to classify typical teaching cases. We classified into 5 type collaborative learning. First, collaborative learning in the classroom. Second, remote collaborative learning between classroom and classroom. Third, Live participation classes. Forth, project collaborative learning. Fifth, using virtual reality in collaborative learning. In addition, we could identify that there is a difference compared to the conventional learning. It became possible to conduct collaborative learning with other students simultaneously or have opening class with both parents and teachers by using Youtube. These examples can be presented as a case to depart from traditional mathematics class in one classroom. In this regard, we will be able to provide several implications about teaching methods utilizing smart device and Internet in future classroom.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.5
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• pp.394-400
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• 2013

WoT (Web of Things) was proposed to realize intelligent thing to thing communications using WEB standard technology. It is difficult to adapt security protocols suited for existing Internet communications into WoT directly because WoT includes LLN(Low-power, Lossy Network) and resource constrained sensor devices. Recently, IETF standard group propose to use DTLS protocol for supporting security services in WoT environments. However, DTLS protocol is not an efficient solution for supporting end to end security in WoT since it introduces complex handshaking procedures and high communication overheads. We, therefore, divide WoT environment into two areas- one is DTLS enabled area and the other is an area using lightweight security scheme in order to improve them. Then we propose a mutual authentication scheme and a session key distribution scheme for the second area. The proposed system utilizes a smart device as a mobile gateway and WoT proxy. In the proposed authentication scheme, we modify the ISO 9798 standard to reduce both communication overhead and computing time of cryptographic primitives. In addition, our scheme is able to defend against replay attacks, spoofing attacks, select plaintext/ciphertext attacks, and DoS attacks, etc.

• Journal of The Korean Association of Information Education
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• v.19 no.4
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• pp.431-440
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• 2015

The purpose of this study is to analyze the influence of digital textbook use for potential risk group of internet addiction and average group. For this, I selected two samples. One was a group to use digital textbook at school, the other was a group not to use that. Then each potential risk group of internet addiction were sort out in two groups by a test of internet addiction. I firstly compared a average user group and a potential risk group of internet addiction in group to use digital textbook. Also, I too did that in group not to use digital textbook. Then I analyzed the relevance of using digital textbook and internet addiction. As a result, I found that using digital textbook have not the relevance with internet addiction. But in this paper, I proposed a way to teach ICT ethical training before students use the digital textbook, because most of potential risk students of internet addiction tend to think they was influenced by digital textbook.

• Journal of Biosystems Engineering
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• v.41 no.4
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• pp.313-318
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• 2016

Purpose: This study measured and analyzed the PTO (power take off) torque of a transplanter according to the planting conditions during field operation. Methods: A torque measurement system was constructed with torque sensors to measure the torque of a PTO shaft, a measurement device to acquire sensor signals, and a power controller to provide power for a laptop computer. The field operation was conducted at four planting distances (26, 35, 43, and 80 cm) and two planting depths using the transplanter on a field with similar soil conditions. One-way ANOVA with planting distance and Duncan's multiple range test at a significance level of 0.05 were used to analyze the PTO torque. The torque ratio was calculated based on the minimum torque using the average PTO torque measured under each planting condition. Results: The average torques on the PTO shaft for planting distances of 26, 35, 43, and 80 cm at a low planting depth were 11.05, 9.07, 7.04, and 3.75 Nm, respectively; the same for planting distances of 26, 35, 43, and 80 cm at a middle planting depth were 12.20, 9.86, 7.94, and 4.32 Nm, respectively. When the planting distance decreased by 43, 35, and 26 cm, the torque ratio at a low planting depth increased by 88, 142, and 195%, respectively. When the planting distance decreased by 43, 35, and 26 cm, the torque ratio at the middle planting depth increased by 84, 128, and 182%, respectively. Conclusions: PTO torque fluctuated by planting distance and depth. Moreover, the PTO torque increased for short planting distances. Therefore, farmers should determine the planting conditions of the transplanter by considering the load and durability of the machine. The results of this study provide useful information pertaining to the optimum PTO design of the transplanter considering the field load.

• Journal of agricultural medicine and community health
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• v.46 no.4
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• pp.218-229
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• 2021

Objectives: The purpose of this study was to suggest the direction of the Healthy Village project for rural residents in accordance with the prolonged COVID-19 by investigating the digital environment for major health problems, the role of a health leader, necessary projects, and non-face-to-face projects for Healthy Village members in the COVID-19 epidemic. Methods: Telephone interview surveys were conducted with 585 residents from November 30, 2020 to December 21, 2020. Results: Health problems perceived by residents were in the order of concerns about infection (48.5%), depression (32.5%), difficulties in using medical services (9.4%), and lack of exercise (7.7%). The role of the health committee in the COVID-19 situation was "encouraging people to follow quarantine rules" with 91.3%. As a necessary health village project, there was a high demand for the provision of health products and mental health projects. 17.9% said that there is a computer or smart device connected to the Internet in their home, and 42.2% said that there is someone in the village who can easily get help if there is a problem in accessing and using Internet information. 36.9% were able to watch videos, and 22.2% were able to use the Internet through public facilities. Conclusion: In a public health crisis, where the provision of public health and medical services to rural residents is not smooth, it is necessary to manage health and quarantine through health leaders in the village, and it is required to establish a digital environment infrastructure that can conduct community participatory health village projects in a non-face-to-face environment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.648-655
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• 2019

This paper proposes the differential development of a Taekwondo electronic body protector. For this development, the most suitable sensor system was selected after analyzing and testing various sensor methods (magnetic sensors, electric capacity sensors, contact switch sensors, and piezo-film sensors) that could be applied in the electronic body protector, the selected sensors were distributed to the body and feet to make a more precise hit score, unlike the existing system in which all sensors are centralized on the body. Furthermore, it aims to illuminate using a lightweight film-type piezoelectric sensor on the body protector. In the case of an existing electronic body protector, all sensors and network device were concentrated on the body protector, so users need to purchase a set if they want it. On the other hand, the proposed system cloud can be used individually using a smart scoring WEP program. The effects of decreasing weight by up to 20% were compared with those of the existing system. Setting up a test facility is very difficult, so more study will be needed to analyze the effects of a hit.

• The Journal of the Convergence on Culture Technology
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• v.7 no.3
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• pp.577-582
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• 2021

Recently, with the development of AR, VR, and smart device technologies, the demand for services based on non-face-to-face environments is also increasing in the fitness industry. The non-face-to-face online home training service has the advantage of not being limited by time and place compared to the existing offline service. However, there are disadvantages including the absence of exercise equipment, difficulty in measuring the amount of exercise and chekcing whether the user maintains an accurate exercise posture or not. In this study, we develop a standard exercise program that can compensate for these shortcomings and propose a new non-face-to-face home training application by using a deep learning-based body posture estimation image processing algorithm. This application allows the user to directly watch and follow the trainer of the standard exercise program video, correct the user's own posture, and perform an accurate exercise. Furthermore, if the results of this study are customized according to their purpose, it will be possible to apply them to performances, films, club activities, and conferences

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.82-92
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• 2022

This study aims to investigate the effect of total electrochemical cell resistance (TECR) on electrochemical impedance (EI) measurements of reinforced concrete (RC) by electrochemical impedance spectroscopy (EIS) using a three-electrode system. A series of experimental study is performed to measure electrochemical behavior of a steel bar embedded in a concrete cube specimen, with a side length of 200 mm, in various experimental conditions. Main variables include concrete dry conditions, coupling resistance between sensing electrodes and concrete surface, and area of the counter electrode. It is demonstrated that EI values remains stable when the compliant voltage of a measuring device is sufficiently great compared to the potential drop caused by TECR of concrete specimens. It is confirmed that the effect of the coupling resistance of TECR is far more influential than other two factors (concrete dry conditions and area of the counter electrode). The results in this study can be used as a fundamental basis for development of a surface-mount sensor for corrosion monitoring of reinforced concrete structures exposed to wet-and-dry cycles under marine environment.