• Journal of Astronomy and Space Sciences
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• 제33권1호
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• pp.1-11
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• 2016

Over the last few years, the data obtained using the Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope has provided new insights on high-energy processes in globular clusters, particularly those involving compact objects such as MilliSecond Pulsars (MSPs). Gamma-ray emission in the 100 MeV to 10 GeV range has been detected from more than a dozen globular clusters in our galaxy, including 47 Tucanae and Terzan 5. Based on a sample of known gammaray globular clusters, the empirical relations between gamma-ray luminosity and properties of globular clusters such as their stellar encounter rate, metallicity, and possible optical and infrared photon energy densities, have been derived. The measured gamma-ray spectra are generally described by a power law with a cut-off at a few gigaelectronvolts. Together with the detection of pulsed γ-rays from two MSPs in two different globular clusters, such spectral signature lends support to the hypothesis that γ-rays from globular clusters represent collective curvature emission from magnetospheres of MSPs in the clusters. Alternative models, involving Inverse-Compton (IC) emission of relativistic electrons that are accelerated close to MSPs or pulsar wind nebula shocks, have also been suggested. Observations at >100 GeV by using Fermi/LAT and atmospheric Cherenkov telescopes such as H.E.S.S.-II, MAGIC-II, VERITAS, and CTA will help to settle some questions unanswered by current data.

• Journal of Astronomy and Space Sciences
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• 제30권2호
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• pp.83-85
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• 2013

Anomalous X-ray pulsars (AXPs) are thought to be magnetars which are young isolated neutron stars with extremely strong magnetic fields of > $10^{14}$ Gauss. Their tremendous magnetic fields inferred from the spin parameters provide a huge energy reservoir to power the observed X-ray emission. High-energy emission above 0.3 MeV has never been detected despite intensive search. Here, we present the possible Fermi Large Area Telescope (LAT) detection of ${\gamma}$-ray pulsations above 200 MeV from the AXP, 1E 2259+586, which puts the current theoretical models of ${\gamma}$-ray emission mechanisms of magnetars into challenge. We speculate that the high-energy ${\gamma}$-rays originate from the outer magnetosphere of the magnetar.

• 유통과학연구
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• 제11권11호
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• pp.41-47
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• 2013

Purpose -This paper aims to understand how easy and convenient it is for consumers to use mobile services. A mobile service combines hardware and software with information technology. To specifically meet the needs of users of mobile applications, the context of usability was identified in consumer mobile services. Research Design, Data, and Methodology - For usability measurement and evaluation, appliances and software were the main target: this applied to an expanding range, such as a Personal Digital Assistant (PDA), mobile phones, and wired and wireless integrated services. This study extended the Technology Acceptance Model (TAM) by examining the roles of two characteristics of mobile applications'usage: usability and usefulness. Results - The study tested the research model using a structural equation modeling (SEM) technique. Results showed no significant differences between the two models. Usability comprised learnability, efficiency, memorability, errors, and satisfaction: the motivation for using a mobile application was understood as being the usefulness and easy-of-use of the mobile application. This empirical study validated the proposed research model and hypotheses, and found that the hypotheses could be supported. Finally, the phenomena derived from the causal relationships in usability were identified, and their implications considered.

• 디지털산업정보학회논문지
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• 제7권4호
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• pp.153-168
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• 2011

UCC paradigm based on Web 2.0 has made new business models and came to the forefront as a commercial media. The purpose of this study is to analyze the customer attitudes toward UCC and it effects as a commercial media. Based on prior studies of Internet and Web advertising, informativeness, entertainment, irritation, trust, usefulness, ease of use, incentives, innovativeness, and flow were identified as affecting factors of the attitude of UCC advertising. Results show that all factors except ease of use and incentives significantly related to the attitude of UCC advertising in Korea. In China, all factors except informativeness, entertainment, and usefulness were found to be significantly related to the attitude of UCC advertising. Customer attitude toward UCC advertising was also found to be significantly related to the such effects as brand attitude, word of mouth and intention to buy in both countries. This study contributes to improve the understanding of UCC as a commercial media and provide the base of activation strategies for it according to the cultural differences.

• Journal of Information Technology Applications and Management
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• 제21권2호
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• pp.49-79
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• 2014

The adoption of technology has always been of interest to academicians and practitioners of the field of Management Information System. This is so because without proper and adequate adoption, technology-no matter how beneficial or advanced it may be-will be of little value to users. Numerous researches, such as the researches of the Technology Acceptance Model (TAM) or the Unified Theory of Acceptance and Use of Technology (UTAUT), had been conducted to understand the human nature in association with the adoption or rejection of technologies that have bombarded the users. The coming of smart technologies (i.e., smart phones and devices), however, seems to have fundamentally changed the environment for adoption. The ubiquity combined with mobility of technology, especially when it comes to mobile apps, seem to make the old PC era of two-stage-pre and post-adoption models obsolete. A new model of adoption that identifies the determinants of technology acceptance and continuance is needed for the smart age. To this end, this paper undertakes an empirical study, by analyzing 229 users of Social Networking Service (SNS) mobile apps, to identify the role of user experience on the multi-stage adoption of technology, and provides results that User Experience (UX) plays the crucial role of bridging the separate stages of pre and post adoption of technologies. The paper concludes by providing practical implications of the new model as it relates to mobile apps and technologies, and recommendations for further studies to get a better understanding of technology adoption in the smart age.

• Journal of Information Technology Applications and Management
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• 제17권2호
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• pp.187-205
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• 2010

This study takes a holistic approach to understand the diffusion of IPTV services by combining the adoption-diffusion model and the use-diffusion model of innovation. IPTV service, a leading digital converged application coupling media content with telecommunications, has been recently launched commercially in Korea. We created a structural model of adoption-diffusion, using the perceived easeof-use and usefulness of TAM(Technology Acceptance Model) as mediating variables, and a structural model of use-diffusion, with the rate of use and the variety of use as mediating variables. To empirically analyze these models, non-users of IPTV were surveyed using the adoption-diffusion model to identify factors influencing their intention to subscribe to the service. Meanwhile, users of IPTV were surveyed using the use-diffusion model to determine the factors that influence their satisfaction with the service and their intention to re-use it. Under the adoption-diffusion model, we found that trialability, household innovativeness and perceived risk were the determinants of user satisfaction with IPTV, and perceived ease-of-use, the mediating factors. Under the use-diffusion model, complementarity and communication were shown to be the determinants of users' satisfaction with IPTV, and variety of use, the mediating factor. We also found that consumers' intention to re-use IPTV was strongly influenced by its relative advantage and perceived risk.

• Journal of Information Technology Applications and Management
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• 제17권2호
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• pp.71-90
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• 2010

Electronic learning(or e-learning) has created hype for companies, universities, and other educational institutions. It has led to the phenomenal growth in the use of web-based learning and experimentation with multimedia, video conferencing, and internet-based technologies. Many researchers are interested in the factors that affect to the performance of e-learning or e-learning services. In this sense, this study is aimed at proposing e-learning system reuse prediction models in which e-learner intention to reuse influence factors(i.e., system accessibility, system stability, information clarity, information validity, self-regulated efficacy, computer self-efficacy, perceived usefulness, perceived ease of use, flow, and parental expectation) affect e-learner intention to reuse positively. A web survey was conducted for the full members of the e-learning education institute A in Seoul, Republic of Korea, an exclusive e-learning company that provides real time video lectures via the desktop conferencing system. The web survey was conducted for 20 days from November 5, 2009, through the e-learning web site of the company A. In this study, three data mining techniques were used : the multivariate discriminant analysis, CART, and C5.0 algorithm. This study was conducted to provide the e-learning service providers, e-learning operators, and contents developers with marketing and management strategies for improving the e-learning service companies, based on the data mining analysis results.

• 인터넷정보학회논문지
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• 제20권1호
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• pp.113-124
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• 2019

Recently, Omni Channel Services has been considered the most innovative business strategy. Omni-Channel sees a variety of channels from all channels viewpoints, organically combining each channel to provide a seamless experience for consumers. In other words, Omni-Channel is not simply a systematic integration of channels, but a means of delivering consistent services to consumers in all processes through a strategy to an organic connection. The aim of this study is to provide a comprehensive insight into the decision factors affecting the adoption of Omni-channel. For this purpose, an empirical analysis is conducted on the course of acceptanceof the Omni-channel service based on the Unified Theory of Acceptance and Use of Technology (UTAUT) and Task-technology fit (TTF), an effective model frequently selected to describe the acceptance of service in the introduction phase of new information technology. As a result of the study, it was confirmed that the task characteristics and the technical characteristics had a positive effect on the task-technology fit, and the task-technology fit had a positive effect on the performance expectancy. In addition, task-technology fit, performance expectancy, and social influence have a positive effect on the intention to use the Omni-Channel. This study is intended to deliver an experimental meaning by proposing a strategical measure to understand the behaviorsand uses of consumers in the Omni-channel service environment and increase the customer satisfaction for the system.

• 인터넷정보학회논문지
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• 제22권5호
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• pp.27-33
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• 2021

With the broad adoption of the Internet of Things (IoT) in a variety of scenarios and application services, management and orchestration entities require upgrading the traditional architecture and develop intelligent models with ultra-reliable methods. In a heterogeneous network environment, mission-critical IoT applications are significant to consider. With erroneous priorities and high failure rates, catastrophic losses in terms of human lives, great business assets, and privacy leakage will occur in emergent scenarios. In this paper, an efficient resource slicing scheme for optimizing federated learning in software-defined IoT (SDIoT) is proposed. The decentralized support vector regression (SVR) based controllers predict the IoT slices via packet inspection data during peak hour central congestion to achieve a time-sensitive condition. In off-peak hour intervals, a centralized deep neural networks (DNN) model is used within computation-intensive aspects on fine-grained slicing and remodified decentralized controller outputs. With known slice and prioritization, federated learning communications iteratively process through the adjusted resources by virtual network functions forwarding graph (VNFFG) descriptor set up in software-defined networking (SDN) and network functions virtualization (NFV) enabled architecture. To demonstrate the theoretical approach, Mininet emulator was conducted to evaluate between reference and proposed schemes by capturing the key Quality of Service (QoS) performance metrics.

• 유통과학연구
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• 제22권6호
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• pp.33-44
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• 2024

Purpose: This study aims to measure how information quality, system quality, security, usefulness, and ease of use of Augmented Reality (VR) and Virtual Reality (AR) influence user satisfaction, motivating intelligent travel technology developers to improve VR/AR quality to meet customer requirements. Research design, data and methodology: This study investigates users interested in travelling in Ho Chi Minh City and Nha Trang City, Vietnam. The research model was implemented using an online questionnaire and face-to-face from 405 valid samples. To evaluate the scale's reliability, the study used the software SPSS 20. Test research hypotheses and evaluate measurement and structural models. This research uses AMOS 20 software. The proposed model is firmly grounded in the Information System Success model (ISS) and the Technology Acceptance Model (TAM), providing a solid theoretical foundation for our research. Results: Results show that consumer perceptions of information quality, system quality, security, usefulness, and ease of use have a positive impact on the perceived quality of VR/AR, thereby influencing tourists' travel intention. Conclusions: The results of this research enrich the theoretical understanding of consumer behaviour toward intelligent technology products in tourism, providing management implications for manufacturers to improve the quality of tourism products and satisfy user requirements in experience before considering choosing a destination.