• Resources Recycling
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• v.27 no.3
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• pp.16-29
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• 2018

In this study, metal and nonmetal contents and their economic values in ICT devices such as smart phones and laptop computers were evaluated. The electronic devices made by LG and Samsung were disassembled into 5 parts, which are printed circuit board assembly, battery, display, case and other electronic components. Metal and nonmetal contents in these parts were analyzed, and their economic values were calculated via multiplying the materials' contents by metal price obtained from KOMIS or nonmetal exchange price acquired from Korean recycling markets. Finally, the materials' contents and values according to each electronic parts and electronic devices were calculated. The results showed that the value of the smartphones and laptop computers of LG are 4,449.6 KRW (28,506 KRW/kg) and 6,830.2 KRW (7,053 KRW/kg), and those of Samsung are 1,849.3 KRW (13,499 KRW/kg) and 6,667.5 KRW (4,831 KRW/kg), respectively. It was also found that most of the value was concentrated in batteries and printed circuit board assemblies. In addition, Co, Au and Cu were found to be the most valuable resources in the devices.

• Journal of Internet Computing and Services
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• v.9 no.6
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• pp.1-13
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• 2008

Trusted Computing is a hardware-based technology that aims to guarantee security for machines beyond their users' control by providing security on computing hardware and software. TPM(Trusted Platform Module), the trusted platform specified by the Trusted Computing Group, acts as the roots for the trusted data storage and the trusted reporting of platform configuration. Data sealing encrypts secret data with a key and the platform's configuration at the time of encryption. In contrast to the traditional data sealing based on binary hash values of the platform configuration, a new approach called property-based data sealing was recently suggested. In this paper, we propose and analyze a new property-based data sealing protocol using the weakest precondition concept by Dijkstra. The proposed protocol resolves the problem of system updates by allowing sealed data to be unsealed at any configuration providing the required property. It assumes practically implementable trusted third parties only and protects platform's privacy when communicating. We demonstrate the proposed protocol's operability with any TPM chip by implementing and running the protocol on a software TPM emulator by Strasser. The proposed scheme can be deployed in PDAs and smart phones over wireless mobile networks as well as desktop PCs.

• Journal of Convergence for Information Technology
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• v.10 no.11
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• pp.47-54
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• 2020

This study proposes an NFC-based payment system that considers user convenience while expanding the existing payment method for RFID-based individual food and logistics waste equipment. In line with this trend, I proposed to apply NFC to the existing RFID-based food meter to release the food in the meantime and to address the problem of re-carrying due to card loss, card not possessed, and non-filling, and the question that could not be identified by various cumbersome procedures. NFC's function alone has been certified for its convenience, which led to its introduction and research in the period of time. Of course, we need to negotiate fees with the transportation card company, but if we see a market share related to transportation card soon, we think smooth negotiations will take place. NFC method will be expanded to all phones with iPhone NFC opening. Therefore, in the next study, we intend to apply the payment system in NFC by linking with local currency, mobile vouchers, and card companies, which are being paid as respective payment means according to the recent emergency support system for COVID-19.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.1
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• pp.9-17
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• 2010

In this study, von Mises stress and total strain energy density characteristics of lead pin in PGA (Pin Grid Array) packages have been calculated by using the FEM (Finite Element Method). FEM computation is carried out with various heat treatment conditions of lead pin material under $20^{\circ}$ bending and 50 mm tension condition. Results show that von Mises stress locally concentrated on lead pin corners and interface between lead pin head and solder. von Mises stress and total strain energy density decrease as heat treatment temperature of lead pin increases. Also, round shaped corner of lead pin decreases both von Mises stress and total strain energy density on interface between lead pin head and solder. This means that PGA package reliability can be improved by changing the mechanical property of lead pin through heat treatment. This has been known that solder fatigue life decreases as total strain energy density of solder increases. Therefore, it is recommended that both optimized lead pin shape and optimized material property with high lead pin heat treatment temperature determine better PGA package reliability.

• 대한공업교육학회지
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• v.39 no.1
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• pp.247-261
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• 2014

Education about invention in elementary schools has thus far be conducted mostly through special activities and talented activities rather than through normal curricula. However, with the implementation of the 2007 amended curricula, invention education was reflected as a normal subject unit in the practical subject (technology and home economics) curricula, thereby laying groundwork for invention education being able to be provided through normal subject classes. Thus, at the time when invention education has been reflected as a normal subject unit, it is meaningful to research the effects of elementary school students' experience in invention education on their invention attitudes. This study sought to research the effects of elementary school students' experience or non-experience in invention education on their invention attitudes, targeting those in regional talent private schools who did not take invention talent classes, those who received invention education, and those who did not receive invention education at all. The conclusion of this study is outlined as follows. First, students' experience in invention education proved to be positive in boosting their invention attitude, and continued invention education experience like with students in regional talent invention schools significantly boosted their invention attitudes. Second, considering that students' actual experience in invention education had positive effects on their invention attitudes, the reflection of invention education in the amended curricula was found to be very desirable in improving elementary students' attitudes about invention. Third, according to gender, male students' invention attitude level was found to be higher than that of female students, suggesting that male students more worked on computers, electronic (smart) devices and machines in daily life, leading them to further develop invention attitudes.

• KIPS Transactions on Software and Data Engineering
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• v.7 no.4
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• pp.129-134
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• 2018

Recently, the artificial neural network (ANN) model is a promising technique in the prediction, numerical control, robot control and pattern recognition. We predicted the outside temperature of greenhouse using ANN and utilized the model in greenhouse control. The performance of ANN model was evaluated and compared with multiple regression model(MRM) and support vector machine (SVM) model. The 10-fold cross validation was used as the evaluation method. In order to improve the prediction performance, the data reduction was performed by correlation analysis and new factor were extracted from measured data to improve the reliability of training data. The backpropagation algorithm was used for constructing ANN, multiple regression model was constructed by M5 method. And SVM model was constructed by epsilon-SVM method. As the result showed that the RMSE (Root Mean Squared Error) value of ANN, MRM and SVM were 0.9256, 1.8503 and 7.5521 respectively. In addition, by applying the prediction model to greenhouse heating load calculation, it can increase the income by reducing the energy cost in the greenhouse. The heating load of the experimented greenhouse was 3326.4kcal/h and the fuel consumption was estimated to be 453.8L as the total heating time is $10000^{\circ}C/h$. Therefore, data mining technology of ANN can be applied to various agricultural fields such as precise greenhouse control, cultivation techniques, and harvest prediction, thereby contributing to the development of smart agriculture.

• Journal of Information Management
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• v.43 no.1
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• pp.109-134
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• 2012

This study, focusing on process of online Word-of-Mouth(oWOM) adoption in applications market which is a major issue of recent mobile industry, tried to empirically analyze how main characteristics of oWOM affect trust and process of oWOM adoption. To do this, based on understanding about applications market and precedent studies on online communication and Elaboration Likelihood Model(ELM), I developed the research model and proposed seven hypotheses. The subjects were smart phone users who ever used review in mobile applications market. The study method was questionnaire survey. As a result, trust in review was suggested as prerequisite for consumers to accept on-line review in mobile applications market. And it was empirically proved that for the customers to feel trust, these are necessary - positive assessment on argument quality, vividness of delivered explanation, and neutrality of message. The theoretical implications of this study are that based on studies on oWOM, factors affecting trust in review were explored in the environment of mobile applications market with less judgement clues for decision making compared to other on-line media and then, these factors were conceptualized. From the practical view, this study suggested implication on what attributes companies or developers can strategically utilize while investigating prerequisites of oWOM adoption.

• Asia pacific journal of information systems
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• v.23 no.4
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• pp.29-51
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• 2013

In line with network technology development and smart device penetration, the social network service (SNS) has expanded its influence. The SNS which is a service based on communication and sharing among people, has grown based on users' voluntary engagement and participation and its influence has appeared beyond the cyberspace into the overall areas of domestic and foreign culture and society. In particular, SNS-based real-time communication during diverse disasters, can help prevent further damage. By sharing information on social donation activities and environmental campaigns, people have used SNS as a tool to change the society in a more positive way. Such series of activities functioning as a power to change the society have been made much faster and wider through the help of a new media called SNS. To better understand such trends, we are required to study about the SNS and its user relationships first. In this context, this study sought to identify the effects of people's desire to build friendships through SNS on the voluntary and society-friendly activities of people. This study considers online pro-social behavior and proposes online citizenship behavior. Citizenship behavior has been examined in organization context. That is, organizational citizenship behavior explains an employee's pro-social behavior in an organization context. Organizational citizenship behavior is characterized by the individual's helping others and promoting the functioning of the organization. By applying organizational citizenship behavior to an online context, we propose online citizenship behavior, an individual's pro-social behavior in an online context. An individual's pro-social behavior, i.e., online citizenship behavior, could be considered as a way for the better management of online community and society. It also needs to examine the development of online citizenship behavior. This study examined online citizenship behavior from the friendship desire. Because online society or community is characterized by online relationships between members, the friendship between members would lead to pro-social behavior, i.e., helping others and promoting the functioning of the online society, in such online context. This study further examines the antecedents of friendship desire in terms of SNS interactivity with its four factors. The findings based on the survey from real SNS users explain that the three factors of SNS interactivity (connectivity, enjoyment, and synchronicity) increases online friendship desire which then increases online citizenship behavior significantly. This study contributes to the literature by examining the key role of online friendship desire in leading to online citizenship behavior and identifying its antecedents in terms of SNS characteristics. The findings in this study also provide guidance on how to manage online society and how to promote the effective functioning of SNS.

• Journal of the Korea Convergence Society
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• v.12 no.5
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• pp.373-383
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• 2021

Our society is aging rapidly. In this super-aged society, the increase in healthcare costs are considered a national problem that undermines the sustainability of social security. Various services for healthcare for the elderly have been promoted to address this. However, most of them have focused on healthcare after the outbreak of chronic diseases and lack preventive healthcare. Most of the preventive healthcare projects are only pilots. In this paper, the current status of health care services for senior citizens at home and abroad was analyzed and based on this, the limitations and improvements were analyzed to propose the establishment of IoT-based Total Silver Care Center. IoT-based Total Silver Care Center may be conveniently monitored the health status of the elderly through various sensors, medical devices, and smart bands. And based on this, it can improve the quality of nursing services through time-saving and work efficiency of nursing providers. In addition, health care interventions may be provided in a timely manner if there is a change in the health status of users. And real-time imaging systems can help overcome mental difficulties.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.6
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• pp.711-718
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• 2019

Spectrum analyzer and electromagnetic field meter were used to investigate the EM generation behaviour in different types of home electrical appliances. During microwave oven operation, the EM power measured at a point 30cm apart was measured in the range of 8~11mW/㎡, the strength of the low frequency magnetic field was 60~80mG and the electric field strength was measured at 150~160V/m. For smart phone wireless charging pad, it was measured at an electromagnetic power of 0.4mW/㎡, an electric field of 160 V/m and a magnetic field of 1mG at a point 10cm away. For microwave oven and wireless charging pad, if used within 10cm, the size of the electric field has been measured at a large value that exceeds the human body protection standard and may be hazardous to humans. On the other hand, home appliances such as TVs, hairdryers and refrigerators all showed very low levels of electromagnetic waves, electric fields and magnetic fields, with no harmful effects seen. For electromagnetic shielding, the metal Cu fabric and metal foil had a high level of EM shielding, while polymer films had a low EM shielding characteristic.