• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.12
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• pp.67-74
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• 2004

AES is frequently used as a symmetric cryptography algorithm for the Internet. Wireless embedded systems increasingly use more conventional wired network protocols. Hence, it is important to have low-cost implementations of AES for thor The basic architecture of AES unrolls oかy one full cipher round which uses 20 S-boxes together with the key scheduler and the algorithm repeatedly executes it. To reduce the implementation cost further, the folded architecture which uses only eight S-box units was studied in the recent years. In this paper, we will study a low-cost AES implementation for wireless communication technology based on the folded architecture. We first improve the folded architecture to avoid the sixteen bytes of additional state memory. Then, we implemented a single byte architecture where only one S-box unit is used for data encryption and key scheduling. It takes 352 clocks to finish a complete encryption. We found that the maximum clock frequency of its FPGA implementation reaches about 40 MHz. It can achieve about 13 Mbps which is enough for 3G wireless communication technology.

• Journal of Broadcast Engineering
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• v.16 no.5
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• pp.722-737
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• 2011

In this paper, we propose an estimation of network jitter that occurs when transmitting TCP packets containing MPEG-2 TS in progressive streaming service over wired or wireless Internet networks. Based on the estimated network jitter size, we can calculate required de-jitter buffering time to absorb the network jitter at the receiver side. For this purpose, by exploiting the PCR timestamp existing in the TS packet header, we create a new timestamp information that is marked in the optional field of TCP packet header to estimate the network jitter. By using the proposed de-jitter buffering scheme, it is possible to employ the conventional T-STD buffer model without any modification in the progressive streaming service over IP networks. The proposed method can be applicable to the recently developed international standard, MPEG DASH (dynamic adaptive streaming over HTTP) technology.

• Journal of Information Technology and Architecture
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• v.10 no.2
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• pp.251-261
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• 2013

The appearance of various mobile Internet environment access to existing networks of mobile devices is easier to tell. In addition, mobile device users to use the wireless environment than a wired environment, user profile information is readily available features. Mobile devices have features that use alone. These characteristics of mobile devices to apply the personalization service is the best system. This paper proposes for mobile device users a personalized mobile music content recommendation service. This service propose to utilizes the user's access history information using time-weighting and collaborative filtering. Access history information can find out information of user interest. Using this information, consider the preference of music genre and time-weighted based on the recommendations makes the music. This method the problem of the traditional music recommendation system, point user's favorite music genre is changing over time do not consider that to solve the problem.

• Journal of Korea Multimedia Society
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• v.15 no.7
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• pp.931-940
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• 2012

Social networking services which spreading rapidly is a system using interrelationship of people by internet or mobile. SNS is a network system of the human-centered. In this paper, in order to make robot become a member of social networks we studied the necessary elements and formation. For robot with communication function and sensing, autonomous, collision avoidance method and communication protocol is needed to let Robot share the present conditions dangerous or special situation. We realized this after investigating necessary sensor for SNS, studying robot's collision-avoidance method, and defining protocol of robot for SNS. Also, we suggested and implemented the wired and wireless integrated communications method.

• Journal of The Korean Association of Information Education
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• v.12 no.1
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• pp.99-107
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• 2008

Over online education based on wired Internet technologies, due to recent development of various mobile technologies, education based on mobile environment becomes popular. In the meanwhile, the young students are more interested in game-based education that provides more interaction and instant feedback than one-way cramming education. The purpose of this thesis is to develop a new motivation model for mobile environment and apply the model to the elementary school students. The proposed model, based on Keller's motivation model, is designed to increase study effects through motivating students with various game strategies. The proposed motivation model has the following characteristics. First of all, the best game genre can be provided for each study theme in early planning stage. Second, the model can allow students to have more interests in their study activity by providing various edutainment elements. Third, a stage of producing game synopsis and concrete scenario is included in motivation model. The stage enables more complete combination of game and mobile motivation strategies. Finally, the proposed model allows contents developed to be appled in teaching plan without any refinement. That is, the model allows a teaching plan to be extracted from study contents instantly.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.1B
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• pp.1-8
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• 2006

Currently, there are many efforts underway to provide Internet service on integrated wireless and wired networks. Supporting IP mobility is one of the major issues to construct IP based wireless network. Mobile IP has been proposed to solve the IP Mobility problem. But, in processing frequent handoffs in cellular based wireless access network, Micro mobility protocols have been proposed to solve these problems. Micro mobility protocols proposed the Cellular IP, HAWII, and Hierarchical Mobile IP. Cellular IP attracts special attention for it's seamless mobility support in limited geographical areas. New BS must be known to occur begging of handoff in Cellular IP indirect handoff. Therefore during perceiving of hanoff, packet loss or packet duplication still can occur in Cellular IP indirect handoff, which results in the degradation of UDP and TCP performance. In this paper, we propose a enhanced indirect handoff scheme for Cellular IP. Proposed handoff scheme is using a crossover node to minimize the signalling procedure and using a buffering to minimize the packet loss or packet duplication.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5834-5840
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• 2013

Along with the development of high-speed, wired and wireless Internet technology, various harmful images in a form of photos and video clips have become prevalent these days. In this paper, we suggest a method of automatically detecting adult images by extracting woman's nipple areas which represent obscenity of the image. The suggested algorithm first segments skin color areas in the $YC_bC_r$ color space from input images and extracts nipple's candidate areas from the segmented skin areas through the suggested nipple map. We then select real nipple areas by using geometrical information and determines input images as harmful images if they contain nipples. Experimental results show that the suggested nipple map-based method effectively detects adult images.

• Journal of Digital Contents Society
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• v.10 no.1
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• pp.87-96
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• 2009

Digital Broadcast Service is being very popular and the delivery mechanism for digital broadcast content through IP network has progressed constantly, due to the advance of video and audio compression and network technologies. From these trends, in Korea, the commercial IPTV service starts in this year after the law related to IPTV is enacted last year. Since IPTV service, which integrates broadcast and communication services, can give an infrastructure for fusion of communication and interactive multimedia data service, IPTV service is attractive. Recently, by the advent of various wireless connection technologies and the mobile devices of high capability, Mobile IPTV, which has an advantage of not only IPTV but also mobile TV, has gained much interest. In this paper, we review a necessary ingredient for Mobile IPTV in the next generation wired/wireless convergence network environment which consists of heterogeneous wireless access networks. In addition, we propose the scheme for user mobility and service session mobility management using RTSP protocol and introduce the service gateway concept to guarantee the extension of IPTV service platform.

• Journal of KIISE
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• v.43 no.4
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• pp.460-469
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• 2016

Internet of Things (IoT) is an environment where various devices are connected to each other via a wired/wireless network and where the devices gather, process, exchange, and share information. Some of the most important types of IoT devices are mobile IoT devices such as smartphones. These devices provide various high-performance services to users but cannot be supplied with power all the time; therefore, power management appropriate to a given IoT environment is necessary. Power management of mobile IoT devices involves complex relationships between various entities such as application processors (APs), HW modules inside/outside AP, Operating System (OS), platforms, and applications; a method is therefore needed to systematically analyze and manage these relationships. In addition, variabilities related to power management such as various policies, operational environments, and algorithms need to be analyzed and applied to power management development. In this paper, engineering principles and a method based on them are presented in order to address these challenges and support systematic development of IoT device power management. Power management of connected helmet systems was used to validate the feasibility of the proposed method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.6
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• pp.1096-1101
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• 2004

By a tremendous expansion of Internet users, there's a number effects that cause the phenomenon of bottlenecked switching packets from routers. In order to tear down this problem, distributed system is applicable to almost every highly performed router systems. The main processor of distributed system, which manages routing table, commands IPC to delivering the forwarding table line processor that eases functionalities of the router. This makes the system having wired-speed forwarding function based on the hardware so that the performance of the network can be enhanced. Therefore, IPC, which assign a part of router, is necessary to exchange data smoothly and the constitution of IPC using Ethernet is widely adapted as a method for saving investment. In this paper, R-IPC mechanism improve the packet-processing rate over 10% through changed from defect of conventional Ethernet IPC, that is, 2 layer processing to TCP/IP or UDP/ IP into 1 layer processing for efficient packet forwarding.