• Journal of Advanced Marine Engineering and Technology
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• v.33 no.4
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• pp.569-577
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• 2009

Mobile information retrieval is an evolving branch of information retrieval that is centered on mobile and ubiquitous environments. In general, mobile devices are characterized by lightweight, low power, small memory, small display, limited input/output, low bandwidth, and so on. Some of these characteristics make it impossible to apply general information retrieval to mobile environments without any modification. In order to relieve this problem, we design and implement an information retrieval system for mobile devices like wireless phones, PDA and handheld devices. We use document summarization techniques to alleviate the limitation of small display and user profiles to retrieve the most proper documents for each individual user for personalized search. Futhermore we use meta-search to lighten some burdens visiting several portal sites. In this paper, we have implemented and demonstrated the proposed mobile information retrieval system on the domain of travel and received good evaluation from users subjectively.

• Archives of design research
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• v.17 no.3
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• pp.441-448
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• 2004

Mobile devices such as mobile phones or PDAs are considered as main interlace tools in ubiquitous computing environment. For searching information in mobile device, it should be possible for user to input some text as well as to control cursor for navigation. So, we should find efficient interlace method for text input in limited dimension of mobile devices. This study intends to suggest a new approach to mobile interaction using camera based virtual keyboard for text input in mobile devices. We developed a camera based virtual keyboard prototype using a PC camera and a small size LCD display. User can move the prototype in the air to control the cursor over keyboard layout in screen and input text by pressing a button. The new interaction method in this study is evaluated as competitive compared to mobile phone keypad in left input efficiency. And the new method can be operated by one hand and make it possible to design smaller device by eliminating keyboard part. The new interaction method can be applied to text input method for mobile devices requiring especially small dimension. And this method can be modified to selection and navigation method for wireless internet contents on small screen devices.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.1
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• pp.183-190
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• 2012

Mobile web applications are different from desktop web applications because of their small screen size and small user input devices. Therefore user interface designers have spent their effort and time to re-design the user interface of mobile web applications to meet these differences. In this paper, we introduce five user interface patterns for mobile web applications to reduce their effort and time. Two of them are for utilizing small screen size efficiently, and they are space overloading pattern and data filtering pattern. These patterns enable designers to reduce screen usage. The other three patterns - data suggestion pattern, input reuse pattern, and incremental data input pattern - are for helping users' data input on mobile devices. These three patterns enable users to reduce direct data input. Our work will help user interface designers develop mobile web interface to utilize screen space efficiently and get data with less errors and less efforts from users.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.676-678
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• 2002

In this work, we present the novel scheduling algorithm of the multimedia data retrieval for the mobile disk drive. Our algorithm is focused on minimizing the power consumption involved in data retrieval from the local disk drive. The prime commodity in mobile devices is the electricity. Strict restriction on power consumption requirement of the mobile device put unique demand in designing of its hardware and software components. State of the art disk based storage subsystem becomes small enough to be embedded in handhold devices. It delivers abundant storage capacity and portability. However, it is never be trivial to integrate small hard disk or optical disk drive in handhold devices due to its excessive power consumption. Our algorithm ARM in this article generates the optimal schedule of retrieving data blocks from the mobile disk drive while guaranteeing continuous playback of multimedia data.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.17-20
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• 2008

A clustering scheme for ad hoc networks is aimed at managing a number of mobile devices by utilizing hierarchical structure of the networks. In order to construct and maintain an effective hierarchical structure in ad hoc networks where mobile devices may move at high mobility, the following requirements must be satisfied. The role of each mobile device for the hierarchical structure is adaptive to dynamic change of the topology of the ad hoc networks. The role of each mobile device should thus change autonomously based on the local information. The overhead for management of the hierarchical structure is small. The number of mobile devices in each cluster should thus be almost equivalent. This paper proposes an adaptive multihop clustering scheme for highly mobile ad hoc networks. The results obtained by extensive simulation experiments show that the proposed scheme does not depend on mobility and node degree of mobile devices in the ad hoc network, which satisfy the above requirements.

• Journal of Information Processing Systems
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• v.10 no.1
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• pp.92-102
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• 2014

In recent years, there has been growing interest in secure pairing, which refers to the establishment of a secure communication channel between two mobile devices. There are a number of descriptions of the various types of out-of-band (OOB) channels, through which authentication data can be transferred under a user's control and involvement. However, none have become widely used due to their lack of adaptability to the variety of mobile devices. In this paper, we introduce a new OOB channel, which uses accelerometer-based gesture input. The gesture-based OOB channel is suitable for all kinds of mobile devices, including input/output constraint devices, as the accelerometer is small and incurs only a small computational overhead. We implemented and evaluated the channel using an Apple iPhone handset. The results demonstrate that the channel is viable with completion times and error rates that are comparable with other OOB channels.

• Journal of Korea Entertainment Industry Association
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• v.13 no.5
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• pp.119-126
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• 2019

Watching movies is common on a big screen like a theater or on a big-screen TV. nowadays, small platform such as mobile devices is increasing rapidly for watch a movie. These changes are deeply related to the advent of Internet-based video streaming services such as OTT. OTT's development has provided in free video viewing system without using the set-top box is free from the limitations of time and space. Leading the market is Netflix[1], which started its business with Internet-based DVD rental service. Netflix, which is growing in tandem with the mobile market, had 193.26[2] million members as of the end of 2018. Other OTT participating companies include content-based Pooq, TVing, platform-based Olleh TV Mobile, Oksusu and LTE video portal. The size of such new growth projects has grown gradually, with 25.4 percent of all smartphone users currently watching video content with small mobile devices. Therefore, de-largeization, it is thought that visual language is needed for viewing small mobile devices that are capable of OTT services. To this end, this paper will identify the problem in viewing popular video content with small mobile devices and Survey and study its impact on viewers using the questionnaire.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.151-153
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• 2002

Mobile handhold devices such as PDA(Personal Digital Assistant) and Cellular Phone are more and more popular for personal web surfing. But today, most mobile handheld devices have relatively poor web browsing capability because of the small bandwidth of wireless connection, the small speed of CPU, the small capacity of RAM and Flash ROM, the small display size of LCD and the short lifecycle of battery. Users have to endure bigger communication latency than Desk PC's one because of these factors. In this paper, we propose an effective pre-refresh mechanism for handheld device's embedded web browser so as to make user's web surfing faster. The experiment was done using the simulator designed by ourselves and the experiment result demonstrates the proposed mechanism has a good performance to make web surfing faster.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.9
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• pp.3120-3137
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• 2021

Small-sized IoT wireless sensing devices can be deployed with small aircraft such as drones, and the deployment of mobile IoT devices can be relocated to suit data collection with efficient relocation algorithms. However, the terrain may not be able to predict its shape. Mobile IoT devices suitable for these terrains are hopping devices that can move with jumps. So far, most hopping sensor relocation studies have made the unrealistic assumption that all hopping devices know the overall state of the entire network and each device's current state. Recent work has proposed the most realistic distributed network environment-based relocation algorithms that do not require sharing all information simultaneously. However, since the shortest path-based algorithm performs communication and movement requests with terminals, it is not suitable for an area where the distribution of obstacles is uneven. The proposed scheme applies a simple Monte Carlo method based on relay nodes selection random variables that reflect the obstacle distribution's characteristics to choose the best relay node as reinforcement learning, not specific relay nodes. Using the relay node selection random variable could significantly reduce the generation of additional messages that occur to select the shortest path. This paper's additional contribution is that the world's first distributed environment-based relocation protocol is proposed reflecting real-world physical devices' characteristics through the OMNeT++ simulator. We also reconstruct the three days-long disaster environment, and performance evaluation has been performed by applying the proposed protocol to the simulated real-world environment.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.2
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• pp.157-164
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• 2005

With the advances of wireless technologies and mobile computing, m-commerce is being realized on many kinds of mobile devices. Service contents for m-commerce are usually newly written to meet specific characteristics of user's mobile devices, thus requiring formidable efforts. So, it is very important to effectively exploit the Internet product information currently being provided for e-commerce. However, bringing those Internet contents to mobile devices is far from straightforward due to the limitations of mobile devices such as little memory, small displays, low processing speeds, and so forth. In this paper, assuming that the Internet products are represented in XML, we suggest four methods to construct the object hierarchy for effectively viewing the documents on the mobile devices. We then compare and analyze them by experiments in terms of response times and required memory size.