• Journal of Digital Convergence
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• v.13 no.8
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• pp.245-251
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• 2015

If a digital signage system is operated in PC mounted in the Window OS then the implementing price is very high. For resolving this problem, we used the Smartphone mounted in ARM Cortex family of multi-core processor-based mobile platform. We developed a low-power low-cost digital signage system and a remote convergence content management program based on web server. This convergence system manages advertising content to a remote control device anywhere using remote control technology. This system is one integrated system with display and is a low-power consumed and is developed in very efficient hardware interface. And condition sensors(intensity of illumination, temperature, weather, GPS etc) is equipped in the developed system. Automatic contents builder and Context-aware SMIL module is also implemented in the convergence system. We achieved over 50% power savings comparing with conventional Window OS system and 16 points multi-touch in our system.

• Journal of Korea Multimedia Society
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• v.8 no.1
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• pp.71-78
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• 2005

When a PDA is used as a mobile terminal in an infrastructure network based on 802.11b standard wireless LAN, we measured and evaluated the performance of multimedia data transmission. In general, PDAs are mainly used tot receiving bulk data like multimedia data. However, while a PDA as a mobile host transfers multimedia data to a desktop PC as a fixed host in such a network, the time taken to receive data from the PC to the PDA is always longer than the time taken to send data from the PDA to the PC by at least 53%. Thus, we consider some critical factors that affect the time taken to receive Our experimental results show that with the PDA the time taken to access a file for writing is longer than the time taken to access a file for reading of to 4.11 times. In addition, a dramatic change of the site of the receiver window, from 686 bytes to 32,383 bytes, prolongs the time taken to receive. To transfer data without any inter-packet interval for the PDA and to increase the size of the TCP receive buffer will be effective in improving the delay to receive data.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12A
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• pp.1876-1882
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• 1999

In this paper, we have proposed a FCB detection algorithm for the GSM system which is european cellular standard. The detection algorithm can be implemented using received signal sampler, correlator, and post detection combiner. GSM mobile phone can use the proposed algorithm for detection of the Broadcasting Channel, and to obtain the initial timing estimate. The proposed algorithm has a architecture which is suitable for DSP or ASIC implementation, and required memory size is small. The performance of the algorithm is a function of the processing data window size and the threshold values. Proper window size and the threshold values can be determined by analyzing the correlator and combiner. The proposed algorithm has been implemented using DSP, and the performance was verified using baseband simulation. The simulation assumed frequency offset values of 0ppm and 15ppm with the receiver filter bandwidth set at both minimum and maximum. It is shown that the algorithm is robust under various assumptions, and suitable for real implementations.

• Journal of Internet of Things and Convergence
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• v.6 no.4
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• pp.15-19
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• 2020

In this paper, we propose a optimal CW(Conention Window) synchronization scheme in IEEE 802.11 WLANs. IEEE 802.11 WLANs support DCF(Distributed Coordination Function) mode for the MAC(Medium Access Control) operation. In DCF, the CW increases exponentially according to the collisions and becomes minimum CW according to the success of data transmissions. However, since the base minimum CW value is hardware or standard specific, the number of active stations and network status are not considered to determine the CW value. Even though the researches on optimal CW have beend conducted, they do not consider the optimal CW synchronization among mobile stations which occur network performance degradation. Therefore, this paper calculates the optimal CW value and shares it with mobile stations in the network.

• Journal of KIISE:Databases
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• v.30 no.3
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• pp.296-309
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• 2003

One of commercial applications of mobile computing is ATIS(Advanced Traveler Information Systems) in ITS(Intelligent Transport Systems). In ATIS, a primary mobile computing task is to compute the shortest path from the current location to the destination. In this paper, we have studied the shortest path re-computation problem that arises in the DRGS(Dynamic Route Guidance System) in ATIS where the cost of topological digital road map is frequently updated as traffic condition changes dynamically. Previously suggested methods either re-compute the shortest path from scratch or re-compute the shortest path just between the two end nodes of the edge where the cost change occurs. However, these methods we trivial in that they do not intelligently utilize the previously computed shortest path information. In this paper, we propose an efficient approximate shortest path re-computation method based on the dynamic window scheme. The proposed method re-computes an approximate shortest path very quickly by utilizing the previously computed shortest path information. We first show the theoretical analysis of our methods and then present an in-depth experimental performance analysis by implementing it on grid graphs as well as a real digital road map.

• Cartoon and Animation Studies
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• s.34
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• pp.367-386
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• 2014

The development of science was crucial to recent advancements in design such as digital contents, UI, GUI, UX design. Not until the DOS evolved into Windows OS were many kinds of digital media design created, namely due to the invention of the computer mouse. A necessary element of mobile phones and Window OS is icons, since icons act as visual symbols, touch buttons and gateways into software content. Icons have undergone many stages of development simultaneously with developments in digital science. We can observe changes in mobile icon design from Skeuomorphism Design to Minimalism to Flat Design. These changes were caused by macro-level trends in design across all other industries. Apple iPhone's Skeuomorphism Design of 2013 evolved into IOS7's Minimalism and Flat Design of 2014. In the mobile world, flat design will again create big changes in design. This research aims to contribute to basic research data of GUI design that are used by creators of mobile apps to understand and anticipate future trends.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.1
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• pp.128-132
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• 1996

In [1], it is shown that a subclass of ETBFs, which are self-dual ETBFs, can be expressed as a weighted average of median subfiltered outputs. In this paper, we extend this result to general ETBFs. In particular, we show that any ETBF can be represented as a weighted average of minimum (or maximum) subfiltered outputs. These representations naturally lead to a subclass of ETBF, called the K-th order ETBF (K-ETBF) that employs only those subfilters whose window sizes are less than or equal to K. By designing K-ETBFs under the mean square error criterion for various values of K and applying them to restore noisy signals, the tradeoff between the performance and the complexity of this class of filters is examined.

• Journal of Korea Multimedia Society
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• v.15 no.8
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• pp.986-995
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• 2012

In this paper we propose a real-time moving object tracking method on a smart phone camera. By considering the limit of non-learning approach on low-performance platforms, we use the sliding-window detection technique based on histogram features. We solve the problem of the time-consuming histogram computation on each sub-window by adapting the integral histogram. For additional speed and tracking performance, we propose a new adaptive bin method. From the experiments on our dataset, we achieved high speed performance demonstrating 34~63 frames per second.

• Journal of Advanced Navigation Technology
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• v.14 no.2
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• pp.253-259
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• 2010

Wireless mesh network is flexible network like Ad hoc network or bluetooth together based on base station. But, wireless mesh network shows high packet loss and when TCP was created, however as it was design based on wired link, wireless link made more transmission error than wired link. It is existent problem of TCP congestion control algorithm that TCP unfairness and congestion collapse over wireless mesh network. When TCP operation occurs with the packet loss where is not the congestion loss, it brings the performance degradation which is serious. In this paper, in order to improve efficient TCP congestion control algorithm in wireless mesh network, we proposed that TCP can adaptively regulate the congestion window in wireless link.

• Korean Chemical Engineering Research
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• v.47 no.3
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• pp.316-320
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• 2009

UV curable hard and color coatings were formed on polycarbonate(PC) films. The coating materials were composed of a commercially available end-capped polyester(EB830), diacrylate monomer(HDDA), silicon acrylate, photoinitiator, and organic dye as a coloring agent. The surface properties of coating films were evaluated, and the influences of the compositions of coating materials were investigated. The coating films showed high transmission and good adhesion between coating layer and PC substrate. And the coating films exhibited higher hardness than bare PC film. The coating films with various colors were obtained by wet process, and the clear and color window lenses for mobile phone were prepared successfully.