• ETRI Journal
• /
• v.30 no.4
• /
• pp.535-545
• /
• 2008

This paper introduces a systematic top-down and bottom-up design methodology to assist the designer in the implementation of continuous-time (CT) cascade sigma-delta (${\Sigma}{\Delta}$) modulators. The salient features of this methodology are (a) flexible behavioral modeling for optimum accuracy-efficiency trade-offs at different stages of the top-down synthesis process, (b) direct synthesis in the continuous-time domain for minimum circuit complexity and sensitivity, (c) mixed knowledge-based and optimization-based architectural exploration and specification transmission for enhanced circuit performance, and (d) use of Pareto-optimal fronts of building blocks to reduce re-design iterations. The applicability of this methodology will be illustrated via the design of a 12-bit 20 MHz CT ${\Sigma}{\Delta}$ modulator in a 1.2 V 130 nm CMOS technology.

• Journal of Information Technology Services
• /
• v.12 no.4
• /
• pp.41-57
• /
• 2013

As the usage of SNS has grown dramatically over the last years, it has been used in various sectors not just a tool for communication. In particular, corporate companies actively use Facebook as a tool for corporate marketing. Corporate companies communicate with their customers by providing service or events information. In this study, empirical analysis was carried out on corporate companies that are using Facebook as a marketing tool, thus finding out the influencing factors in continued usage of Facebook Fan Page users. In addition, analysis of the factors will be investigated according to continued usage of the users, where the user's intention will differ depending on how corporate companies operate and deal with the Facebook Fan Page. Factors affecting the user's satisfaction, perceived usefulness, and perceived playfulness were deducted through the analysis of the existing literature study on corporate company's continued intention on the usage of Facebook Fan Page. Accordingly, factor affecting this such as relationship, speed, content diversity, which are the media characteristics of the Facebook were deducted and finally hypothesized. In addition, the type of corporate company's Facebook Fan Page was divided into event type, communication type, information service type. And hence investigated the factors that differed from the continued usage depending on the type. Results analysis shows that perceived usefulness affected only relationship, speed, content diversity. Furthermore, analysis shows that corporate company's Fan Page of communication and event types are the factors that affect the usage intention which meant it only affected the perceived enjoyment. On the basis of this study, we are able to present an implication of value where corporate company use it as a marketing tool, through factors from continued usage of coroporate company's Facebook Fan Page users.

• Journal of Power System Engineering
• /
• v.22 no.6
• /
• pp.58-66
• /
• 2018

The use of external gear pumps is an effective way to achieve adequate performance at low cost when composing hydraulic systems. The biggest drawback, on the other hand, is the accompanying noise. Gears of continuous contact shape are actively used for the pump recently. The continuous contact shape must be the helical type due to the nature of the gear pump that is driven only by the drive gear. In this paper the theoretical shape of continuous contact gear is analyzed using simple rack shape of straight lines and two circular arcs. Using such geometry, the theoretical equation will be developed by envelope curves according to the conjugate gear shape rules. After checking the validity of the theory by the shape of gear rules, the grinding shape was also developed. The 3D shapes using equation can be also drawn. It was also shown that contact ratio and radius of curvature are easily developed by the theoretical equations.

• The Journal of the Korea Contents Association
• /
• v.16 no.1
• /
• pp.214-229
• /
• 2016

Since financial crisis, sharing economy emerged as a result of economic stagnation, emerging environmental-friendly trend and increasing smartphone penetration, which led to reducing unnecessary consumption and increasing the practical usage of resources. This indicates the possibility that the sharing economy service will develop in this hyperconnectivity era in terms of increasing consumer utility. In this study, the author, therefore, empirically analyzed the factors that affect the continuous usage from the experience of service use and the causal relationship between the factors by regulating the success of sharing economy service as the continuous use after the acceptance of service. The findings demonstrated that the perceived value and network externality had a significant effect on both trust and satisfaction, and the perceived risk had a significant effect on trust. In addition, trust affected both satisfaction and continuous use intention significantly, and satisfaction also had a significant effect on continuous use intention. And the perceived value and risk, and network externality mediated trust and satisfaction, thereby having a significant effect on continuous use intention. Through this research, the author intends to provide an opportunity to enhance the competitiveness of sharing economy service under an uncertain business environment by way of identifying the success factors of the sharing economy service whose important is growing in recently years and the structural relationship between these factors.

• Phonetics and Speech Sciences
• /
• v.2 no.2
• /
• pp.17-25
• /
• 2010

This study explores whether Koreans exploit their native coda-neutralization process when recognizing words in Korean continuous speech. According to the phonological rules in Korean, coda-neutralization process must come before the liaison process, as long as the latter(i.e. liaison process) occurs between 'words', which results in liaison-consonants being coda-neutralized ones such as /b/, /d/, or /g/, rather than non-neutralized ones like /p/, /t/, /k/, /ʧ/, /ʤ/, or /s/. Consequently, if Korean listeners use their native coda-neutralization rules when processing speech input, word recognition will be hampered when non-neutralized consonants precede vowel-initial targets. Word-spotting and word-monitoring tasks were conducted in Experiment 1 and 2, respectively. In both experiments, listeners recognized words faster and more accurately when vowel-initial target words were preceded by coda-neutralized consonants than when preceded by coda non-neutralized ones. The results show that Korean listeners exploit the coda-neutralization process when processing their native spoken language.

• Journal of Family Resource Management and Policy Review
• /
• v.6 no.2
• /
• pp.65-78
• /
• 2002

The proposes of this study were designed to practical use of credit cards on consumers in Kwang-ju. The 371 subjects formatted questionnaires were analyzed to frequency, percentage, crosstabulation and chi-square test by SPSS WIN 10.0. The main results of this study were as following : First, it is analyzed that most consumers have had more than credit cards. Second, it is tended that consumers have influenced to practical use of credit cards by sex, age, marriage, income and living expenses. Third, consumer is use to the spur of credit card, requirement about businessman, credit card connection system and distinction of sex, age, marriage, income, showed difference of relevant distribution between living expenses all. Based on the above, to make the use of credit cards practical and active, it needs more attention from consumers as well as it needs continuous efforts from the authorities concerned. Accordingly, to prevent consumers from overconsuming possibly by imprudent use of credit cards, it suggests systematic consumer training, from which consumers will learn responsible life as a consumer.

• Journal of Distribution Science
• /
• v.14 no.4
• /
• pp.67-79
• /
• 2016

Purpose - Over recent years, we have concerned about safety and quality on food products because of delivery complexity. The dependence of foreign food products escalate supply of products. And there are often negligent accident of marine and agricultural products. Therefore, the complexity increases the importance of safety on food and information quality for consumers. In spite of the interest augmentation of various interested parties, there is decrease in reliability and effectiveness, if it would be established without the right directivity. For the study, we tried to examine the first considerations the point of - view in service environment and information quality with accepting and diffusing the Traceability System. Then, we tried to verify the relationships between the factors of TS and the determinants of behavior decision. Next, we made efforts to find the mutual relationship among distributors, producers, consumers and the other prerequisite factors from the point of view in service environment and information quality in order to operate effectively the information perspective and system. Research design, data, and methodology - For the purpose of this study, the samples of consumers were targeted to Traceability System, and 661 people have been investigated. Through theoretical discussion of previous research, nine hypotheses were established, the influence of Continuous User Intention in TS. In order to test the hypotheses, a survey had conducted for 661 consumers as opinion leaders in their 20s-60s as data, and structural equation modeling was used. The difference analysis between Agricultural and Marine Products in TS; SPSS 22.0 and AMOS 22.0 were used for statistical analysis. Results - The major findings from this study were as follow; all factors of information quality excluding completeness and a social-impact had effects on the ease of use; all factors excluding understand ability in information quality and a social-impact had effects on the usefulness; completeness and social-impact had effects on perceived value; the ease of use had effects on usefulness and perceived value; usefulness had effects on perceived value and the intention of continuous use. From the results of different analysis, the CPLT(Completeness) factor has positive effects on Easy of USE and PV(Perceived Value) strongly in agricultural products. On the other hand, Social Duty has positive effects on Easy of Use strongly in marine products. Conclusion - In the age of information overflowing, TS will be a burden for users if it places too much emphasis upon accessibility. To accept and diffuse TS safely, therefore, Information System should be settled first into initial market formation. In addition, if TS elements are considered in conjunction with information factors and user environment, the acceptance and diffusion of TS would make synergy effect, even better. That is, this study contributes to the acceptance and diffusion of Traceability System. Accordingly, information quality will be settled into initial market formation. Also, social-impact element will be considered in conjunction with information quality's factors, and it will make synergy effect.

• Journal of Forest and Environmental Science
• /
• v.23 no.2
• /
• pp.79-85
• /
• 2007

This survey was carried out to investigate the utilization situation of fire-wood boiler by the questionnaire and personal interview on rural and mountain households of Gangwon province from 1998 to 2005. The questionnaire include 7 questions on installation, 7 questions on fuel, 3 questions on use, and 3 questions on improvement. Each question was analyzed by percentage to investigate the use situation. This survey indicated that the general problems in use of fire-wood boiler are fuel purchase, collection and transportation, that the development of the household heating boiler using wood-based forming fuel which is cheap, small volume, easy handling, convenient purchase and high heat efficiency could be an alternative to improve the problems and that the continuous expansion of the supply of fire-wood boiler can prevent the devastation of forest through the regulation of imprudent fuel supply. Although the financial aid plan on the installation of fire-wood boiler is in active, many petty households in rural and mountain areas lose a chance to install the fire-wood boiler due to the unsatisfactory information. Thus, it will be desirable for municipal government to prepare the information plan to offer the equal chance and condition to all households in rural and mountain areas and to increase the financial aid for the continuous supply of fire-wood boiler.

• Journal of the Korea Society of Computer and Information
• /
• v.27 no.9
• /
• pp.217-224
• /
• 2022

Based on the success model and Expectation Confirmation model of information system, the concept model of mobile bus payment App users' willingness to continue using is constructed by introducing function quality and interface design quality. A total of 264 valid questionnaires are obtained by issuing online questionnaires, and the model is tested by SmartPLS3.0 software The results show that users' perceptions of information quality, system quality and interface design quality will affect users' perceived usefulness and satisfaction through the scene, and then affect users' willingness to continue to use; Perceived functional quality has a significant impact on perceived usefulness, but has no significant impact on satisfaction. Perceived usefulness has a significant impact on user satisfaction.

• Journal of applied mathematics & informatics
• /
• v.42 no.3
• /
• pp.471-481
• /
• 2024

In this paper, the concept of D-sets will be applied to create D-lindelöf spaces, a new type of topological space covering the property. This is performed by using a D-cover, which is a special type of cover. The primary purpose of this work is to introduce the principles and concepts of D-lindelöf spaces. We look into their properties as well as their relationships with other topological spaces. The basic relationship between D-lindelöf spaces and lindelöf spaces, as well as many other topological spaces, will be given and described, including D-compact, D-countably compact, and D-countably lindelöf spaces. Many novel theories, facts, and illustrative and counter-examples will be investigated. We will use several informative instances to explore certain of the features of the Cartesian product procedure across D-lindelöf spaces as well as additional spaces under more conditions.