• Journal of KIISE:Databases
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• v.33 no.1
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• pp.86-101
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• 2006

The bandwidth of channel and the power of the mobile devices are limited on a wireless environment. In this case, data broadcast has become an excellent technique for efficient data dissemination. A significant amount of researches have been done on generating an efficient broadcast program of a set of data items with different access frequencies over multiple wireless broadcast channels as well as single wireless broadcast channel. In this paper, an efficient data allocation method over multiple wireless broadcasting channels is explored. In the traditional approaches, a set of data items are partitioned into a number of channel based on their access probabilities. However, these approaches ignore a variation of access probabilities of data items allocated in each channel. In practice, it is difficult to have many broadcast channels and thus each channel need to broadcast many data items. Therefore, if a set of data items broadcast in each channel have different repetition frequencies based on their access frequencies, it will give much better performance than the traditional approaches. In this paper, we propose an adaptive data allocation technique based on data access probabilities over multiple broadcast channels. Our proposed technique allows the adaptation of repetition frequency of each data item within each channel by taking its access probabilities into at count.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.5
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• pp.401-415
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• 2005

Owing to the improved wireless communication technologies, it is possible to provide streaming service of multimedia with PDAs and mobile phones in addition to desktop PCs. Since mobile client devices have low computing power and low network bandwidth due to wireless network, the transcoding technology to adapt media for mobile client devices considering their characteristics is necessary. Transcoding servers transcode the source media to the target media within corresponding grades and provide QoS in real-time. In particular, an effective load balancing policy for transcoding servers is inevitable to support QoS for large scale mobile users. In this paper, the resource weighted load distribution policy is proposed for a fair load balance and a more scalable performance in cluster-based transcoding servers. Our proposed policy is based on the resource weighted table and number of maximum supported users, which are pre-computed for each pre-defined grade. We implement the proposed policy on cluster-based transcoding servers and evaluate its fair load distribution and scalable performance with the number of transcoding servers.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.4
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• pp.115-129
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• 2007

The ubiquitous and autonomic computing environments is open and dynamic providing the universal wireless access through seamless integration of software and system architectures. The ubiquitous computing have to offer the user-centric pervasive services according to the wireless access. Therefore the roaming services with the predefined security associations among all of the mobile devices in various networks is especially complex and difficult. Furthermore, there has been little study of security coordination for realistic autonomic system capable of authenticating users with different kinds of user interfaces, efficient context modeling with user profiles on Smart Cards, and providing pervasive access service by setting roaming agreements with a variety of wireless network operators. This paper proposes a Roaming Coordinator-based security management framework that supports the capability of interoperator roaming with the pervasive security services among the push service based network domains. Compared to traditional mobile systems in which a Universal Subscriber Identity Module(USIM) is dedicated to one service domain only, our proposed system with Roaming Coordinator is more open, secure, and easy to update for security services throughout the different network domains such as public wireless local area networks(PWLANs), 3G cellular networks and wireless metropolitan area networks(WMANs).

• Journal of the Korea Society of Computer and Information
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• v.27 no.12
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• pp.131-139
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• 2022

In this paper, to verify the authenticity of UxNB that assists terrestrial base stations, the solutions for SI (System Information) security presented in 3GPP TR 33.809 are analyzed from the perspective of UxNB. According to the definition of 3GPP (Third Generation Partnership Project), UxNB is a base station mounted on a UAV (Unmanned Aerial Vehicle), is carried in the air by the UAV, and is a radio access node that provides a connection to the UE (User Equipment). Such solutions for SI security can be classified into hash based, MAC (Message Authentication Codes) based, and digital signature based, and a representative solution for each category is introduced one by one. From the perspective of verifying the authenticity of UxNB for each solution, we compare and analyze the solutions in terms of provisioning information and update, security information leakage of UxNB, and additionally required amount of computation and transmission. As a result of the analysis, the solution for verifying the authenticity of the UxNB should minimize the secret information to be stored in the UxNB, be stored in a secure place, and apply encryption when it is updated over the air. In addition, due to the properties of the low computing power of UxNB and the lack of power, it is necessary to minimize the amount of computation and transmission.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.187-190
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• 2008

Owing to rapid advancements of the mobile computing technologies and the performance of mobile device recently, the data synchronization techniques between severs and mobile clients are getting more and more important. OMA also proposes and recommends standard synchronization methods to use SyncML. However, the feasible data in the method are limited to normal document data, scheduler data, etc. This paper a standard framework based on SyncML. We call it SCGFG. The SCGFG is able to synchronize not only the above data but also GIS data which is very useful in mobile applications. It applies GML, international GIS standard, to the synchronization. By means of using XML, it is also able to resolve the serious problem that is the increase of data volume occurred by SyncML and GML. efficiently. It is highly expected to be useful in the smart synchronization of GIS data among several servers and mobile clients.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.933-936
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• 2008

Mobile devices such as cellular phones and PDA become a part of our life by extreme improvement of Wireless internet and arriving the age of Ubiquitous. Especially it makes increasing rapidly the expectations about a field of remote control that is great advantage of Mobile devices. Existing computer remote control systems are hard to meet user's appropriate manage when error happened because Clients could not recognize the state of several remote controlled computers which connected to web server. This paper Implementation remote computer control system that immediately after errors happen by send error massages in the from of a SMS to client by set the clients with cellular phone that most generally used Mobile devices.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.6
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• pp.197-204
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• 2015

Recent changes in health care environment including aging population and prevalence of chronic disease encourage the adoption of new innovative technological solutions including wearable vital sensors, wireless networks, and smart phone. In this paper, we present an effective at-home lifestyle monitoring system that can be used for self-management and health intervention of patient himself in the Management-by-Exception perspectives. We implemented the filtering and queuing algorithms as a preprocessor of monitoring system to enhance efficiency of proposed system, and the effective UX design for self-management of patients themselves. The 94,467 actual clinic data was used to test the efficiency of the proposed system. As as a result, 64.8% of the incoming vital data was identified to be filtered out.

• Journal of Digital Convergence
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• v.11 no.12
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• pp.407-415
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• 2013

Recently, Interest variety of IT services and computing resources are increasing. As a result, the interest in the security of cloud environments is also increasing. Cloud environment is stored that to provide services to a large amount of IT resources on the Cloud. Therefore, Cloud is integrity of the stored data and resources that such as data leakage, forgery, etc. security incidents that the ability to quickly process is required. However, the existing developed various solutions or studies without considering their cloud environment for development and research to graft in a cloud environment because it has been difficult. Therefore, we proposed wire-wireless integrated Security management Model in cloud environment.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.11
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• pp.247-249
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• 2020

In the era of the 4th industrial revolution, the demand for convergence between ICT technologies is increasing in various fields. Accordingly, a new term that combines data, network, and artificial intelligence technology, DNA (Data, Network, AI) is in use. and has recently become a hot topic. DNA has various potential technology to be able to develop intelligent application in the real world. Therefore, this paper introduces the reviewed papers on the service image placement mechanism based on the logical fog network, the mobility support scheme based on machine learning for Industrial wireless sensor network, the prediction of the following BCI performance by means of spectral EEG characteristics, the warning classification method based on artificial neural network using topics of source code and natural language processing model for data visualization interaction with chatbot, related on DNA technology.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.2
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• pp.57-64
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• 2011

The NGN (Next Generation Network) means the kernel infrastructure technology to provide information and communication services which are able to be used at present and future when a ubiquitous computing era has been realized. In other words, NGN can be the frame providing the same information and communication services anytime and anywhere regardless of wire and wireless. The broadband convergence network that has been built in the public institution has established a broadband multimedia communication network supporting voice telephone, task net, internet network, video conference network, voice over IP (VoIP) network and etc. It is possible for a requested bandwidth and services to be served, only if a broadband convergence network provide the interoperability between the various classes which include a transport network layer, network control layer, service control layer and other layers. In this paper, we analyzed the interoperability issues of the present broadband convergence network and propose a guideline for the future one.