• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.4
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• pp.1351-1372
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• 2022

A self-organizing multiple unmanned aerial vehicles (multi-UAVs) deployment based on virtual forces has a difficulty in ensuring the quality-of-experience (QoE) of users because of the difference between the assumed center for users in a hotspot and an actual center for users in the hotspot. This discrepancy is aggravated in a non-uniform and mobile user distribution. To address this problem, we propose a new density based virtual force (D-VF) multi-UAVs deployment algorithm which employs a mean opinion score (MOS) as a metric of QoE. Because MOS is based on signal-to-noise ratio (SNR), a sum of users' MOS is a good metric not only to secure a wide service area but to enhance the link quality between multi-UAVs and users. The proposed algorithm improves users' QoE by combining virtual forces with a random search force for the exploration of finding multi-UAVs' positions which maximize the sum of users' MOS. In simulation results, the proposed deployment algorithm shows the convergence of the multi-UAVs into the position of maximizing MOS. Therefore, the proposed algorithm outperforms the conventional virtual force-based deployment scheme in terms of QoE for non-uniform user distribution scenarios.

• Spatial Information Research
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• v.18 no.2
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• pp.57-65
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• 2010

Users often visit many stores while comparing the products for purchasing products or products related to it. Given a service providing location information of these stores, users can make their purchase efficiently because of reducing the time and effort they spent for wandering around and obtaining new purchase opportunities by knowing a kind of relevant stores near there. In this paper, for the purpose of providing relevant stores information efficiently, we suggest an Ambient Service Model that consists of three layers: "structured(purchase-related) information space", "real space", and "ambient information space". In the model, stores information collected from the web is grouped and structured automatically by relationships in terms of purchase. And users search relevant stores information by using an Ambient Query that is created by their context in real space. Finally, users obtain relevant stores information that is in the form of hierarchy structure on map interface. Then, users can search other kinds of relevant stores information additionally by using hierarchy structure. Consequently, It is possible to develope a service that users can obtain relevant stores information intuitively without complex search processes through the model. Also, we expect that the model can be used for developing services that provide objects information related to various objects besides stores.

• The KIPS Transactions:PartD
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• v.19D no.2
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• pp.133-138
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• 2012

Queries entered in a search box are the results of users' activities to actively seek information. Therefore, search logs are important data which represent users' information needs. The purpose of this study is to examine if there is a relationship between the results of queries automatically classified and the categories of documents accessed. Search sessions were identified in 2009 NDSL(National Discovery for Science Leaders) log dataset of KISTI (Korea Institute of Science and Technology Information). Queries and items used were extracted by session. The queries were processed using an automatic classifier. The identified queries were then compared with the subject categories of items used. As a result, it was found that the average similarity was 58.8% for the automatic classification of the top 100 queries. Interestingly, this result is a numerical value lower than 76.8%, the result of search evaluated by experts. The reason for this difference explains that the terms used as queries are newly emerging as those of concern in other fields of research.

• Journal of Korea Multimedia Society
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• v.6 no.4
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• pp.601-609
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• 2003

In wireless mobile networks, the service area is partitioned into several registration areas (RAs). Every RA is associated with a mobility database called Visitor Location Register (VLR). The VLR is used to achieve the location management of the mobile terminals. When a mobile terminal enters a new RA, the VLR stores the current location information of the mobile terminal before serving any mobile services. At that time, if the VLR is full, the registration procedure fails, and the system can not deliver services to the mobile user under the existing cellular technology To resolve this problem, we propose a VLR overflow control scheme considering mobility of mobile users to accomodate incoming users during VLR overflow. The performance of the proposed scheme is evaluated by an analytic model in terms of costs for the location search and the location update, and compared with those of the overflow control scheme proposed by Lin[1].

• Asia pacific journal of information systems
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• v.33 no.4
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• pp.957-976
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• 2023

ChatGPT has had a significant impact on society, business, and academia by influencing individuals and organizations through knowledge generation and supporting users in locating conversational inquiries and answers. It can transform how people seek answers by combining human-like conversational skills with AI. By eradicating the cumbersome process of selecting from multiple options, users can conduct preliminary research or create optimized solutions. The purpose of this research is to investigate how consumers use ChatGPT and digital transformation, specifically in terms of knowledge development, searching and recommending, and optimizing accessible possibilities. Using many linked theories, we address the potential implications and insights that can be gained from ChatGPT's early stages and its integration with other applications such as robotics, service automation, and the metaverse. Finally, the application of ChatGPT has practical, theoretical, and phenomenological impacts, in addition to improving users' experiences.

• The Journal of Information Systems
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• v.21 no.3
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• pp.71-97
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• 2012

There has been an upward trend in smartphone sales in Korea as well as the rest of the world. Even though smartphones are now at the peak of their popularity, the fact that they are somewhat limited in terms of their usages for certain purposes is unexpected. Precisely, compared to PC, smartphones typically have smaller display screens with a lower resolution, which make them difficult to use in general. For instance, when customers search the information about products in mobile shopping malls, due to the smaller screen with a low resolution smartphone users may realize that it is not easy and convenient not only to search the information, but also to read the information they found in the shopping malls. This restriction could become one of reasons that lowers the perceived quality of information in the shopping malls, which in turn leads to the reluctance to use the shopping malls. A comprehensive information systems (IS) literature review found that there has been little empirical evidence on perceived information quality that affects smartphone users' intention to use mobile shopping malls. The purposes of this study is to examine 1) the effects of perceived information quality on smartphone users' intention to use mobile shopping malls and 2) the relationships among behavioral beliefs in the middle of independent and dependent variables, such as information satisfaction, perceived usefulness, and customers' attitude toward mobile shopping. A survey was conducted in March 2012. College students and practitioners took participated in the survey. Structural Equation Modeling(SEM) was used for all data analysis. The results found that there is a strong relationship between perceived information quality and smartphone users' intention to use mobile shopping malls. In addition, this study also showed that there are strong relationships among behavioral beliefs. Further research is expected to validate the findings of this study and apply them in specific contexts.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.7
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• pp.1422-1428
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• 2009

In this paper, we consider an independent type cognitive radio system where secondary users can utilize empty channels that are not currently used by primary users having the license to these channels. In the previous works, secondary users search channels sequently or randomly to detect activities of primary user on channels. These channel searching methods however are not suitable to the characteristics of the wireless environment. Therefore, we propose a channel searching method based on the channel list for the purpose of reducing the channel searching time and improving the throughput of secondary users. In the proposed method, we firstly determine weighting value of each channel based on the history of channel activities of primary users and add the weighing value to current channel state buffer. And then, we search an empty channel from channel with smallest value to one with the biggest value. Finally, we compare the performances of the proposed method with those of the sequential channel searching and the random channel searching methods in terms of average channel searching time and average number of transmissions of secondary user.

• Journal of Korean Library and Information Science Society
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• v.26
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• pp.365-400
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• 1997

The interface design for most present query-base model of OPAC systems does not include the function to implement an iterative feedback process till the user arrives at satisfied search results through the interaction with the system. Also, the interface doesn't provide the help function for a user to select pertinent search terms. To formulate a query at the present OPAC system, a user should learn a set of syntax different from system to system. All of above mentioned things make an end-user feel difficult to utilize an OPAC system effectively. This experimental system is attempted to alleviate a few limitations of the present OPAC system by a n.0, pplying the direct-manipulation technique as well as the feedback principle. First, this system makes it unnecessary for a user to learn some syntax for query formulation by providing option buttons for access points. Second, this system makes it possible for a user to decide whether each displayed record is relevant or not, and for keywords included in the relevant records to be automatically stored in order to be used for later feedback. Third, in this system, the keywords stored in [sayongja yongeu bogyanham] can be deleted if unnecessary or can selected as search terms for a query expansion as well as a query modification. Fourth, in this system, after inputting the original query, the feedback process can be proceed without coming back to the previous search step until a user becomes satisfied with the search results. In conclusion, the searching behaviors of heterogeneous users should be continuously observed, analysed, and studied, the findings of which should be integrated into the design for the interface of the OPAC system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.3 no.6
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• pp.628-646
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• 2009

Users want to browse and search various web contents with mobile devices which can be used anywhere and anytime without limitations, in the same manner as desktop. But mobile devices have limited resources compared to desktop in terms of computing performance, network bandwidth, screen size for full browsing, and etc, so there are many difficulties in providing support for mobile devices to fully use desktop-based web contents. Recently, mobile network bandwidth has been greatly improved, however, since mobile devices cannot provide the same environment as desktop, users still feel inconvenienced. To provide web contents optimized for each user device, there have been studies about analyzing code to extract blocks for adaptation to a mobile environment. But since web contents are divided into several items such as menu, login, news, shopping, etc, if the block dividing basis is limited only to code or segment size, it will be difficult for users to recognize and find the items they need. Also it is necessary to resolve interface issues, which are the biggest inconvenience for users browsing in a mobile environment. In this paper, we suggest a personalized adaptation system that extracts item blocks from desktop-based web contents based on user interests, layers them, and adapts them for users so they can see preferred contents first.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.22 no.1
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• pp.281-299
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• 2011

The purpose of this study is to understand and analyze the satisfaction level of users regarding the search and search results of D College Library system implemented by Open API. For the study, 90 students of D College searched the library system with 4 subjects regarding on current affairs and assignments, and then evaluated the satisfaction on search functionality and contents usability. In results, they satisfied search expansion in general. Especially, the satisfaction levels for the convenience of search method and preview was the highest, but that of level for the arrangement and browsing of search results and the searching speed was the lowest. In terms of currentness, relevance, usefulness and utilizability aspects, Naver was the most highly evaluated, followed by library’s database, dissertation/academic journals, Youtube and Flikr. The cause of the unsatisfactory could be reduced when the library system implements the useful and attractive search interface.