• Korean Journal of Materials Research
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• v.34 no.9
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• pp.432-438
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• 2024

Cu-Ti thin films were fabricated using a combinatorial sputtering system to realize highly sensitive surface acoustic wave (SAW) devices. The Cu-Ti sample library was grown with various chemical compositions and electrical resistivity, providing important information for selecting the most suitable materials for SAW devices. Considering that acoustic waves generated from piezoelectric materials are significantly affected by the resistivity and density of interdigital transducer (IDT) electrodes, three types of Cu-Ti thin films with different Cu contents were fabricated. The thickness of the Cu-Ti thin films used in the SAW-IDT electrode was fixed at 150 nm. As the Cu content of the Cu-Ti films was increased from 31.2 to 71.3 at%, the resistivity decreased from 10.5 to 5.8 × 10^-5 ohm-cm, and the density increased from 5.5 to 7.3 g/cm³, respectively. A SAW device composed of Cu-Ti IDT electrodes resonated at exactly 143 MHz without frequency shifts, but the full width at half maximum (FWHM) values of the resonant frequency gradually increased as the Cu content increased. This means that although the increase in Cu content in the Cu-Ti thin film helps to improve the electrical properties of the IDT electrode, the increased density of the IDT electrode deteriorates the acoustic performance of SAW devices.

• Journal of Space Technology and Applications
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• v.4 no.3
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• pp.185-198
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• 2024

Korea Astronomy and Space science Institute (KASI) partnered with the Australian National University (ANU) to develop the adaptive optics (AO) system at the Geochang observatory with a 100 cm optical telescope for multiple applications, including space geodesy, space situational awareness and Korean space missions. The AO system is designed to get high resolution images of space objects with lower magnitude than 10 by using themselves as a natural guide star, and achieve a Strehl ratio larger than 20% in the environment of good seeing with a fried parameter of 12-15 cm. It will provide the imaging of space objects up to 1,000 km as well as its information including size, shape and orientation to improve its orbit prediction precision for collision avoidance between active satellites and space debris. In this paper, we address not only the design of AO system, but also analyze the images of stellar objects. It is also demonstrated that the AO System is achievable to a near diffraction limited full width at half maximum (FWHM) by analyzing stellar images.

• Journal of the Semiconductor & Display Technology
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• v.23 no.3
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• pp.85-90
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• 2024

Conductive charging of electric vehicles has entered a stable stage, and various product lines have been developed and standards have been made. Inductive charging methods can be classified into various other methods such as Indirect Power Transfer, Coupled Magnetic Resonance, and Permanent Magnet Coupled Transfer. Since choosing the most effective charging method for electric vehicles is difficult, standardizing the method of wirelessly transferring power is still a challenge to be achieved in a future. SAE J2954 sets an overall standard of electric vehicle Wireless Power Transport system. This paper proposes a wireless charging module that installs two receiving coils at a certain distance under the vehicle to minimize coil alignment due to incorrect parking and other vehicle full length during static charging. Finally, we developed an ATmega128 MCU-based module prototype and tested it to verify the efficiency of lower misalignment probability in different alignment charging environments compared to conventional single VA coils.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.8
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• pp.66-75
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• 2016

Due to aggressive scaling of device sizes and reduced noise margins, physical defects caused by aging and process variation are continuously increasing. Additionally, with scaling limitation of metal wire and the increasing of communication volume, fault tolerant method in manycore network-on-chip (NoC) has been actively researched. However, there are few researches investigating reliability in NoC with voltage-frequency-island (VFI) regime. In this paper, we propose a table-based routing technique that can communicate, even if link failures occur in the VFI NoC. The output port is alternatively selected between best and the detour routing path in order to improve reliability with minimized hardware cost. Experimental results show that the proposed method achieves full coverage within 1% faulty links. Compared to $d^2$-LBDR that also considers a routing method for searching a detour path in real time, the proposed method, on average, produces 0.8% savings in execution time and 15.9% savings in energy consumption.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.92-101
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• 2017

The SNS website can take full advantage of the characteristics of users to conduct e-commerce. The e-commerce website's organizing ability will be greatly strengthened by SNS and creates greater value for consumers. This article examined the Chinese largest SNS (Weibo) users as research objects, and combined the development status of SNS in China. This article focuses on the influence to consumer's purchase intention in three aspects: number of comments, consumer involvement level, and consumer appealing method and examines how the interaction of the number of comments and consumer appealing method affects the purchase intention. An investigation was conducted on 400 users of SNS and using valid questionnaires to perform reliability analysis, validity analysis, independent sample t-test, and double factor variance analysis using SPSS21. The research results indicated that the number of comments and rational appealing method had significant effect on the purchase intention. The mediating or controlling the purchase involvement level will disturb the influence of the number of comments but will have no effect on the information appealing method.

• Journal of the Korean Society for information Management
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• v.25 no.2
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• pp.183-198
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• 2008

With the purpose of enriching existing catalogues with FRBR, which is the Functional Requirements for Bibliographic Records, in mind, this paper aims to evaluate the impact of bibliographic ontology on the overall system's performance in the field of literature. In doing this, OCLC's FictionFinder(http://fictionfinder.oclc.org) was selected and qualitatively evaluated. In this study 40 university seniors evaluated the following three aspects using the 'transferring thoughts onto paper method': 1) In which ways is this FRBR-aware bibliographical ontology helpful? 2) Are the things which are initially attempted to be helped being helped? 3) Would users seeking one work in particular also see all other related works? In conclusion, this study revealed that, as Cutter claimed in his $2^{nd}$ rule of the library, collocations give added-value to the users and overall ontology provides better interface and usefulness. It also revealed that a system's evaluation with qualitative methodology helped to build full pictures of the system and to grip the information needs of the users when the system is developed. Qualitative evaluations, therefore, could be used as indicators for the evaluation of any information retrieval systems.

• Journal of Distribution Science
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• v.16 no.10
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• pp.65-76
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• 2018

Purpose - This paper investigates how the market value of the firms are impacted by distribution information technology investment in Korea over time and across markets, industries and project characteristics. This is the first empirical study on the market payoffs from the RFID investment in Korea. The purpose of this study is to provide a appropriate guideline for investors and practitioners with respect to the announcement representing RFID adoption in Korea. This reaction guideline will stimulate the practitioners to monitor and evaluate the benefits and costs of the innovative RFID technology. Research design, data, and methodology - This paper employs event study methodology to analyze the payoffs from distribution information technology investment announcements over a fifteen-year period from 2003 to 2017. Event study method is based on the assumptions such as market efficiency, unanticipated RFID invest announcements and no confounding effects in the data. This study collected the information on RFID investment announcements by using a full text search engine Bigkinds provided by Korea Press Foundation over a fifteen-year period from January 2003 through December 2017. This paper selected 88 announcements representing RFID adoption by 46 firms. This paper estimated the payoffs from RFID investment announcement through events windows by using the market model of Mcwilliams and Siegel (1997) and calculated the Z-values. Using this test statistics we could infer if RFID adoption make large differences in abnormal returns across various classifications of the firms. Results - There is significant positive market returns from the announcement representing distribution information technology investment in the pre-2009 time period, the significances of payoffs disappear in the post-2009 time period. For this reason investors or practitioners can understand the importance of market entry time and the fact that the greater rewards may belong to early innovators while late imitators cannot reap such a rewards. This paper also find that there is a large differences in the payoffs from the announcement across markets, industries and project characteristics. Conclusions - Analysing the selected sample of 88 announcements representing RFID Adoption over fifteen-year period from 2003 to 2017, this study find that there is not only significant abnormal excess returns from RFID investment announcements but also there is great differences in the abnormal returns over time and across firm sizes or affiliated markets, industries, and project characteristics. This means that there are considerable values for the investors across various firm classifications. The findings of this paper provide useful implications for the practitioners to make judicious decisions whether to adopt the innovative technologies in general or not considering the various concrete circumstances in Korea.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.9
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• pp.10-17
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• 2007

It opens a new horizon on spintronics for the potential application of MTJ as a universal logic element, to employ the magneto-logic in substitution for the transistor-based logic device. The magneto-logic based on the MTJ element shows many potential advantages, such as high density, and nonvolatility. Moreover, the MTJ element has programmability and can therefore realize the full logic functions just by changing the input signals. This magneto-logic using MTJ elements can embody the reconfigurable circuit to overcome the rigid architecture. The established magneto-logic element has been designed and fabricated on a triple-layer MTJ. We present a novel magneto-logic structure that consists of a single layer MTJ and a current driver, which requires less processing steps with enhanced functional flexibility and uniformity. A 4-bit gray counter is designed to verify the magneto-logic functionality of the proposed single-layer MTJ and the simulation results are presented with the HSPICE macro-model of MTJ that we have developed.

• Journal of Intelligence and Information Systems
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• v.14 no.1
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• pp.117-129
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• 2008

The cost-based scheduling work has been done in both the Operations Research (OR) and Artificial Intelligence (AI) literature. To deal with more realistic problems, AI-based heuristic scheduling approach with non-regular performance measures has been studied. However, there has been little research effort to develop a full inter-job cost propagation algorithm (CPA) for different jobs having multiple downstream and upstream activities. Without such a CPA, decision-making in scheduling heuristics relies upon local, incomplete cost information, resulting in poor schedule performance from the overall cost minimizing objective. For such a purpose, we need two types of CPAs : intra-job CPA and inter-job CPA. Whenever there is a change in cost information of an activity in a job in the process of scheduling, the intra-job CPA updates cost curves of other activities connected through temporal constraints within the same job. The inter-job CPA extends cost propagation into other jobs connected through precedence relationships. By utilizing the cost information provided by CPAs, we propose cost-based scheduling heuristics that attempt to minimize the total schedule cost. This paper develops inter-job CPAs that create and update cost curves of each activity in each search state, and propagate cost information throughout a whole network of temporal constraints. Also we propose various cost-based scheduling heuristics that attempt to minimize the total schedule cost by utilizing the cost propagation algorithm.

• The Journal of the Convergence on Culture Technology
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• v.7 no.3
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• pp.365-374
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• 2021

Recently, the high growth rate and advantages of the crowdfunding market have also led to increased participation of brands and companies, and this also applies to fashion business. Risk has been noted to be a key factor in consumer behavior in crowdfunding. With the high-risk context of crowdfunding where supporters inevitably bear to pay full amount of price before receiving the actual products. Factors enhancing or inhibiting perceived risk of crowdfunding need to be explored. The past literature on perceived risk and consumer attitudes in crowdfunding has expanded, but it has rarely covered the context of experience goods such as fashion products. In addition, the platform characteristics in relation to perceived risk should be addressed. The current study attempts to address the effect of the perceived amount of information offered in a fashion crowdfunding project on perceived risk and the intention to participate in the project. For the experiment of this study, a fictitious crowdfunding page for fashion products was set as the stimuli. A total of 240 Korean participants were recruited and their responses were statistically analyzed using SPSS 24.0 software. In the results, the greater the amount of detailed information about the fashion crowdfunding project, the higher the intention to participate the project. The greater the amount of information provided, the lower the perceived risk of consumers. Moreover, the lowered perceived risk affected the intention of participate. Perceived risk has a partial mediation in the relationship between the amount of information and intention to participate. Theoretical and managerial implications are discussed.