• Journal of Internet Computing and Services
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• v.20 no.2
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• pp.1-7
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• 2019

The latest mobile applications such as augmented reality, virtual reality, and deep learning can be used efficiently in various fields such as emergency management and game. Accordingly the corresponding applications have been developed for these purposes. However modern mobile applications such as augmented reality and virtual reality increase the energy burden on mobile devices. In order for mobile devices to focus their energy on the latest mobile applications, energy consumption should be minimized for communication and networking, such as cognitive radio. In this paper, we propose a method to reduce the energy consumption of Centralized Cooperative Spectrum Sensing (CCSS) scheme in cognitive radio by devising Stop Reporting Algorithm (SRA). Simulation results show that SRA can reduce energy consumption of mobile devices using cognitive radio.

• Journal of Broadcast Engineering
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• v.27 no.2
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• pp.207-215
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• 2022

The latest volumetric technology's high geometrical accuracy and realism ensure a high degree of correspondence between the real object and the captured 3D model. Nevertheless, since the 3D model obtained in this way constitutes a sequence as a completely independent 3D model between frames, the consistency of the model surface structure (geometry) is not guaranteed for every frame, and the density of vertices is very high. It can be seen that the interconnection node (Edge) becomes very complicated. 3D models created using this technology are inherently different from models created in movie or video game production pipelines and are not suitable for direct use in applications such as real-time rendering, animation and simulation, and compression. In contrast, our method achieves consistency in the quality of the volumetric 3D model sequence by linking re-meshing, which ensures high consistency of the 3D model surface structure between frames and the gradual deformation and texture transfer through correspondence and matching of non-rigid surfaces. And It maintains the consistency of volumetric 3D model sequence quality and provides post-processing automation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.5
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• pp.1237-1242
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• 2014

The functions of playing musics and multimedia have become essential in one device as a smart phone since the smart phone appeared. It is very convenient, but it contains controversial arguments about sound quality, so many smart phone users use the music player application. By using these music applications, people start to think about the relationship between music playing and sound quality. However, those applications are not perfect, so it is hard to choose a good application. This thesis is about the advantages of the sound quality of music player applications that are currently sold in Android Market through RightMark Audio Analyzer program, and plans to suggest android music player application system design by analyzing applications by covering disadvantages of these applications.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.9
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• pp.2213-2218
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• 2013

Smart devices such as smart phone, smart TV, tablet, game consoles embrace all categories of Intelligent Communication Device, which enables intelligent applications to be developed, by up loading Context-aware Computing technology that recognizes and reacts nearby diverse phenomena and composing these information, as well as their basic functions. This paper, after saving pre-registered students' movement course and business places harmful to them into students safety network service system, by using location-based service and searching students' movement, considering the degree of breaking away from their regular course, the access to and their stay in crime-crone area, provides the comparative analysis of the system and suggests the ways for safe students guidance.

• Journal of the Korea Society of Computer and Information
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• v.17 no.4
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• pp.109-119
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• 2012

As it is developing and growing up the mobile telecommunication, commercial mobile, and the application on it, the smart phone is attracting public attention techniques, hereafter. In this paper, we can make the context-awareness platform to supply users with the interface for their appropriate contexts using the smart phone. Therefore, we use the sensors in the smart phone, and the values from them are analyzed. As a result, we can estimate the user's contexts, such as the sitting and standing, movement, the lights, positions, locations, etc. In addition, we happen the suitable events from them for users. Therefore, we can provide the perspective interfaces for them. In addition, to prove the more efficiency of the proposed platform, we implemented the shooting game, and could know that the performance is the more advanced than the others. The proposed algorithm can be used for the mobile environments, which high efficiency is required such as the game, or the implementation of mobile applications which are more efficient to the user interfaces, etc.

• Journal of the Korea Convergence Society
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• v.13 no.4
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• pp.17-24
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• 2022

Bitcoin is a peer-to-peer cryptocurrency designed for electronic transactions that do not depend on the government or financial institutions. Since Bitcoin was first issued, a huge blockchain financial market has been created, and as a result, research to predict Bitcoin price data using machine learning has been increasing. However, the inefficient Hyper-parameter optimization process of machine learning research is interrupting the progress of the research. In this paper, we analyzes and presents the direction of Hyper-parameter optimization through experiments that compose the entire combination of the Timesteps, the number of LSTM units, and the Dropout ratio among the most representative Hyper-parameter and measure the predictive performance for each combination based on Bitcoin price prediction model using LSTM layer.

• Journal of Intelligence and Information Systems
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• v.8 no.1
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• pp.103-117
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• 2002

Recently, many researchers have developed applications for automated contract and negotiation using agent technologies on electronic commerce. Especially, they have tried to study negotiation mechanism applying agent instead of buyers and sellers. Traditional researches, however, often had limitations. In the researches of automated negotiation, the agents had to negotiate with the other agents for a simple negotiation issue because the mechanisms were naive. In the researches of negotiation by user interaction, the agents did not have supported the procedures and methodologies for making the automated negotiation but only supported the users by providing communication environment during the negotiation process by users. In this paper, we propose efficient negotiation model using the modified negotiation model of the game theory. In the proposed model, the agents negotiate automatically with the partner agent and make good benefits by the strategic method during the negotiation process. Each agent makes negotiation issues with user's requirements and exchanges its suggestion alternatively in each step of the negotiation process. The agent evaluates degree of satisfaction for the opposite's suggestion and uses it in the next step of suggestion. To find out the negotiation strategies of opposite side, the agent uses teaming by weights of issues. As a result, the agent improves each own benefits for the contract and reduces the unbalance of its benefits through the proposed negotiation mechanism. We implement the negotiating agents according to the proposed mechanism and prove the efficiency of the proposed model by various experimentation.

• Journal of The Korean Association of Information Education
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• v.18 no.3
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• pp.423-432
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• 2014

With wide spread of smart devices, the use of children's smart devices were increased. We have performed an exploratory study about children's use of smart devices in the viewpoint of lives of children. The children was encouraged on the school centered learning by their parents. In this study, we wanted to explore the state of life of children's using of smart devices in the view of the children's life at the age of information society. The results show that there was a difference in children's using of smart devices between big and small city. This research shows that the students have the lack of the experiences of learning of desired usages and learning with devices. In the play with the non-electronic media, outside play was more than indoor play. Half of the answers at the amount of time to play the game and to watch the TV were "within an 1 hour". We know that the proportion of children's indoor play portion is more than outdoor play of it.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.1
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• pp.91-98
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• 2010

This paper proposes authority delegation for secure social community creation and mutual authentication scheme between the community members using proxy signature in community-based ubiquitous networks. In community-based ubiquitous network, User's context-awareness information is collected and used to provide context-awareness network service and application service for someone who need it. For the many reason, i.e. study, game, information sharing, business and conference, social community could be created by members of a social group. However, in community-based ubiquitous network, this kind of the context-awareness information could be abused and created by a malicious nodes for attack the community. Also, forgery community could be built up to attack the community members. The proposed scheme using the proxy signature provides a mutual authentication and secure secret key exchange between community members, and supports secure authority delegation that can creates social community. Also, when delegation of signing authority and mutual authentication, this scheme reduces total computation time compared to the RSA signature scheme.

• Journal of Digital Convergence
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• v.11 no.7
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• pp.157-163
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• 2013

In this paper, we propose a vision and depth information based real-time hand gesture interface method using finger joint estimation. For this, the areas of left and right hands are segmented after mapping of the visual image and depth information image, and labeling and boundary noise removal is performed. Then, the centroid point and rotation angle of each hand area are calculated. Afterwards, a circle is expanded at following pattern from a centroid point of the hand to detect joint points and end points of the finger by obtaining the midway points of the hand boundary crossing and the hand model is recognized. Experimental results that our method enabled fingertip distinction and recognized various hand gestures fast and accurately. As a result of the experiment on various hand poses with the hidden fingers using both hands, the accuracy showed over 90% and the performance indicated over 25 fps. The proposed method can be used as a without contacts input interface in HCI control, education, and game applications.