• Journal of the Korea Society of Computer and Information
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• v.16 no.11
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• pp.113-122
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• 2011

In this paper, we propose an iPhone application that allows the user to pay for donations using the camera, GPS and call functions of the iPhone. As iOS version 3.0 allows the iPhone camera to detect and read bar codes and QR codes, the proposed application uses such codes to identify a product the user wishes to donation. After determining the user's location using the iPhone GPS function, the application can then perform a navigation task that guides the user to a suitable shop or store where the user can make his or her donation. In addition, the application offers an ARS call function that allows the user to make a direct donation, even if the user does not know the telephone number for making such donations. Therefore, the proposed application provides an easy means for the user to pay for donations directly or indirectly.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.3
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• pp.1065-1085
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• 2020

With rapid growth of content demands, device-to-device (D2D) content sharing is exploited to effectively improve the service quality of users. Considering the limited storage space and various content demands of users, caching schemes are significant. However, most of them ignore the influence of the asynchronous content reuse and the selfishness of users. In this work, the user preferences are defined by exploiting the user-oriented content popularity and the current caching situation, and further, we propose the social-aware rate, which comprehensively reflects the achievable contents download rate affected by the social ties, the caching indicators, and the user preferences. Guided by this, we model the collaborative caching problem by making a trade-off between the redundancy of caching contents and the cache hit ratio, with the goal of maximizing the sum of social-aware rate over the constraint of limited storage space. Due to its intractability, it is computationally reduced to the maximization of a monotone submodular function, subject to a matroid constraint. Subsequently, two social-aware collaborative caching algorithms are designed by leveraging the standard and continuous greedy algorithms respectively, which are proved to achieve different approximation ratios in unequal polynomial-time. We present the simulation results to illustrate the performance of our schemes.

• ETRI Journal
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• v.45 no.5
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• pp.887-898
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• 2023

Aerial base stations (ABSs) seem promising to enhance the coverage and capacity of fifth-generation and upcoming networks. With the flexible mobility of ABSs, they can be positioned in air to maximize the number of users served with a guaranteed quality of service (QoS). However, ABSs may be overloaded or underutilized given inefficient placement, and user association has not been well addressed. Hence, we propose a three-dimensional ABS placement scheme with a delay-QoS-driven user association to balance loading among ABSs. First, a load balancing utility function is designed based on proportional fairness. Then, an optimization problem for joint ABS placement and user association is formulated to maximize the utility function subject to statistical delay QoS requirements and ABS collision avoidance constraints. To solve this problem, we introduce an efficient modified gray wolf optimizer for ABS placement with a greedy user association strategy. Simulation results demonstrate that the proposed scheme outperforms baselines in terms of load balancing and delay QoS provisioning.

• IE interfaces
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• v.15 no.1
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• pp.73-81
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• 2002

In mobile phone, complex user interface tend to cause the degradation of product usability. This problem is mainly due to the small hardware user interface of mobile phone. That is, because many functions must be operated in small hardware interface, the principle of one-to-one mapping between a function and a control is disregarded in design, often. In order to resolve this problem, users' characteristics must be considered in the user interface design of mobile phone. So, users' basic characteristics that must be considered in the user interface design of mobile phone were studied through two experiments, questionnaire survey and user testing.

• Journal of Information Technology Applications and Management
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• v.19 no.4
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• pp.213-225
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• 2012

The identified research result can be outlined more specifically as follows: first, informativeness of SNS was giving positive impact to some degree on the user satisfaction; second, connectivity of SNS was giving very positive impact on the user satisfaction; third, accessibility was giving very positive impact on the user satisfaction; forth, usability of SNS was giving very positive impact on the user satisfaction; fifth, amusement of SNS was giving very positive impact on the user satisfaction; the satisfaction level of SNS users gave positive impact on the further intention of SNS users. It was identified, however, that interactiveness of SNS was the factor that did not give much impact on the user satisfaction. This result comes from the analysis that SNS is convenient to actively explore and get further information that users wish to find, while they are insufficient in function to provide the information other users require or exchange information among users through the SNS.

• Journal of information and communication convergence engineering
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• v.7 no.2
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• pp.92-97
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• 2009

Lately, influence of information rises and interest about satisfaction estimation of information providing service is risin. According to rapid change in information environment, information-providing service is being changed in various form, in which center development is made in relation to the effort for customer satisfaction intended to enhance user's satisfaction level through providing more convenient and higher service centered on information service user rather than information service provider. Organizations providing information service is also changing their service from traditional one centered on service provider to that for user's satisfaction and service quality, and evaluation of information service quality and measurement of user's satisfaction as the result of using information service are regarded important. In this respect, it is needed to measure user's satisfaction level for environmental factors of information service and analyze what kind of influence they have to enhance user's satisfaction level of information service. Also function and efficiency of information offer service are important. Therefore, interest for satisfaction survey to heighten contents satisfaction of information-providing service, service satisfaction, satisfaction of user of system satisfaction is increased. In this paper, we propose a model of the user satisfaction index for information-providing services and present the user satisfaction index is measured to the model. Also we this study suggest qualitative improvements of information-providing service required for change to user-centric information-providing service through measuring user satisfaction index of ITFIND system and schemes to improve information quality

• Journal of the Korea Convergence Society
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• v.12 no.2
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• pp.135-146
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• 2021

In this study, in order to provide an app with improved usability to users in the trend of gradually increasing the number of users of music streaming services, usability tests were conducted by conducting interviews before and after the execution of the screen test technique and the performance measurement method and contextual. Usability test was conducted using the Inquiry method. Usability tests were conducted by one user each from their teens to their 50s, and were conducted on Melon, YouTube Music, Genie, and FLO apps with many service users. As a result of the usability test, the icon does not sufficiently represent the function and is not recognized as an interactive button, which is overlooked by the user, the problem that the user does not recognize due to lack of visual effect when the function is activated, The problem was derived. In this regard, suggestions for improving the user screen, such as intuitively changing the icon for each app, adding a visual effect of the screen when the function is activated, and adjusting the position so that the function has continuity, were presented along with the visual data.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.8
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• pp.24-34
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• 1992

A process control language is developed using function block configuration, to simplify software development for large scale process control systems, and to implement advanced control algorithms with ease. A function block parser and controller is implemented to be suitable for multi-loop control systems having hierachical structure. On-line change of controller parameter is possible, and inclusion of user defined function block is also possible. By adding plant model block, control performance can be checked in advance. Function blocks of the Smith Predicotor, auto-tuners are implemented to demonstrate usefulness of function block configuration.

• Journal of the Korea Convergence Society
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• v.9 no.8
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• pp.135-141
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• 2018

The purpose of this study is to analyze the user experience and suggest the necessary improvements, in the blockchain based social platform Steemit. First, I investigated what is the blockchain and the characteristic of social platforms based on blockchain system. The honeycomb model was used to investigate and analyze the Steemit user experience, and the quantitative and qualitative data were analyzed through questionnaires and in-depth interviews. As a result of the research, the voting function, which is core function of the service in use, has high usefulness. Improvements suggestion that the editing tools and the abuse of voting function should be improved. I hope that this study will be used as a basic research material to improve the user experience of blockchain based social platforms.

• Geophysics and Geophysical Exploration
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• v.17 no.3
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• pp.171-178
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• 2014

Aeromagnetic survey generally require much more pre-processing steps than that of common land survey due to several complex and cumbersome steps included in pre-processing stage. Therefore it is desirable to use specific processing tool especially based on graphic user interface. For this purpose, aeromagnetic pre-processing software based on graphic user interface under the Windows environment, called $KMagLevelling^{TM}$ was developed and briefly introduced. In an aspect of its user-friendliness and originality, three noticeable features of $KMagLevelling^{TM}$ are summarized as the following (1) function of representation and handling for large amount of aeromagnetic data set as a visualization in the form of flight-path (2) function of selective exclusion of unwanted data by using survey area information expressed as polygon, and (3) function of selective removal processing for the irregular flight-path data acquired within the entire survey area by implementing the segmentation of flight-path technique.