• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.1
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• pp.38-55
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• 2013

Wireless network systems provide fast data transmission rates and various services to users of mobile devices such as smartphones and smart pads. Because many people use high-performance mobile devices, the use of real-time multimedia services is increasing rapidly. However, the preoccupation of resources by real-time traffic users is causing harm to other services-for example, frequent call interference, lowered service quality, and poor network performance. This paper suggests a resource allocation algorithm for effective traffic service support in a hybrid network. The main objective is to obtain an optimum value of data rates by comparing user requirements with the amount of resources that can be allocated. A new mechanism based on Adaptive-Quality of Service (QoS) and a monitoring system based on Queue-Aware are proposed. Adaptive-QoS supports effective resource control according to the type of traffic service, and the monitoring system based on Queue-Aware measures the amount of resources in order to calculate the maximum that can be allocated. We apply our algorithm to a test system and use Qualnet 4.5.1 to evaluate its performance.

• Journal of Internet Computing and Services
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• v.21 no.4
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• pp.1-8
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• 2020

In order to reach Ultra-Reliable Low-Latency communication, one of 5G aims, Multi-access Edge Computing paradigm was born. The idea of this paradigm is to bring cloud computing technologies closer to the network edge. User services are hosted in multiple Edge Clouds, deployed at the edge of the network distributedly, to reduce the service latency. For mobile users, migrating their services to the most proper Edge Clouds for maintaining a Quality of Service is a non-convex problem. The service migration problem becomes more complex in high mobility scenarios. The goal of the study is to observe how user mobility affects the selection of Edge Cloud during a fixed mobility path. Mobility-Aware Service Migration (MASM) is proposed to optimize service migration based on two main parameters: routing cost and service migration cost, during a high mobility scenario. The performance of the proposed algorithm is compared with an existing greedy algorithm.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.10
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• pp.4886-4907
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• 2019

The use of mobile devices is increasing in multimedia applications. The multimedia contents are delivered to mobile users over heterogeneous networks. Due to fluctuation in bandwidth and user mobility, the service providers are facing difficulties in providing Quality of Service (QoS) guaranteed delivery for multimedia applications. Multimedia applications depend on QoS parameters such as delay, bandwidth, and jitter to offer better user experience. The existing schemes use the single source and multisource delivery but are unable to balance between stream quality and network congestion for mobile users. We proposed a Quality Oriented Multimedia Content Delivery Scheme (QOMCDS) for the mobile cloud to deliver better quality multimedia contents for the mobile user. The multimedia contents are delivered to the mobile device based on the device's parameters and network environment. The objective video quality assessment models like Peak Signal-to-Noise Ratio (PSNR), Structural Similarity (SSIM), and Video Quality Measurement (VQM) are used to measure the quality of the video. The client side Quality of Experience metric such as Startup delay, Rebuffering events, and Bitrate switch count was used for evaluation. The proposed scheme is evaluated using dash.js and is compared to existing schemes. The results show significant improvement over existing multimedia content delivery schemes.

• Journal of Communications and Networks
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• v.7 no.2
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• pp.207-221
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• 2005

The proliferation of wireless local area networks (WLANs) offering high data rate in hot spot area have spurred the demand for possible WLANs and third-generation (3G) cellular network integration solutions as the initiative step towards 4G systems. This paper provides a novel architecture for seamless location-aware integration of WLANs into 3G cellular networks and also an analysis for the efficient handover techniques. We introduce location as a key context in secure roaming mechanism for context-aware interworking in 4G systems. The fast secure roaming with location-aware authentication is implemented at an entity called location-aware service (LAS) broker that utilizes the concepts of direction of user and pre-warming zone. The location-ware interworking architecture supports seamless roaming services among heterogeneous wireless networks including WLANs, wireless metropolitan area networks (WMANs), and 3G cellular networks. This paper also includes a description of procedures needed to implement efficient mobility and location management. We show how the LAS broker with pre-warming and context transfer can obtain significant lower latency in the vertical handover.

• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.327-333
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• 2006

낯선 환경에서 이동하며 여행하는 여행자들은 문화와 언어 등의 차이로 인해 어려움에 부딪히며 다양한 문제를 갖는다. 그로 인해 만족스러운 여행을 달성하지 못하거나, 안 좋은 추억들을 가지게 된다. 이러한 상황에 부딪힐 때마다 여행자들은 문제를 해결하기 위한 정보를 매 순간마다 찾아 사용하게 된다. 따라서, 만족하는 여행을 달성하기 위하여 자신의 상황에 가장 적절한 정보에 대한 니즈가 증대 되었다. 본 연구는 '미래의 유비쿼터스 컴퓨팅 시대의 여행자가 만족스러운 여행을 하기 위하여 정보 서비스는 어떻게 제공되어야 하는가?' 라는 물음으로부터 시작하였고, 이를 위하여 사용자의 상황에 따라 가장 적절한 서비스를 하는 컨텍스트 인식 서비스가 낯선 상황을 매번 접하게 되는 여행자들에게 유용한 방법으로 제시될 수 있을 것이라는 전제하에 진행되었다. 본 연구에서는 여행자가 처한 상황에서 가장 필요로 하는 최적의 정보를 휴대전화 인터페이스를 통해 얻음으로써, 만족스러운 여행을 할 수 있도록 컨텍스트 인식 서비스를 디자인하는 방법을 제안하였다. 연구의 내용으로는 첫 번째로, 여행자의 상황을 사용자의 목적을 이루기 위한 행위의 단계의 시점으로 보았다. 두 번째로, 여행자들은 목적의 행위단계마다 다른 정보를 사용하며, 원하는 정보의 우선순위는 발생하는 컨텍스트와 관련이 있다는 사용자 조사의 결과 도출하였다. 세 번째로, 이를 바탕으로 여행자가 가지는 목적 중 '식사하기'를 중심으로 각 상황마다 여행자가 필요로 하는 정보를 휴대전화를 통해 제공하는 컨텍스트 인식 서비스의 방법을 제안하고, 마지막으로, 이를 사례에 적용하여 서비스의 컨셉을 구체화하였다.

• Journal of Digital Convergence
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• v.14 no.12
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• pp.105-110
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• 2016

As smart devices have proliferated and network speed and accessibility of mobile have accelerated, mobile cloud services that can do the same tasks by various devices are promoted. This paper explores the analysis of use intention of mobile cloud services and influencing factors. We develop and apply a convergence technology acceptance model which combines TAM, VAM and UTAUT. The proposed model verifies some hypotheses to aware the significant factors of use intention of mobile cloud services with TAM, VAM and UTAUT including additional mobile cloud service characteristics such as mobility, high availability, easy accessibility and scalability. Eventually, this research can not only help users gain insights into mobile cloud service use intention, but also help mobile cloud service providers to develop more effective mobile cloud service and their business strategy in the future.

• Journal of Service Research and Studies
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• v.2 no.2
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• pp.91-98
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• 2012

The emergence of new types of embedded computing devices and developments in wireless networking are broadening the domain of computing from the work place and home office to other facets of everyday life. This trend is expected to lead to a proliferation of Internet of Things (IoT) environments, in which inexpensive and interconnected computing devices are capable of supporting users in a range of tasks. Context-aware computing is a key source to develop such smart services. However, there are many challenges to enable services to be smart; Heterogeneous Computing Environments, Resource Limitations, Large Amount of Data Produced, and Different Requirements for Context Interpretation. Because of these challenges, there are difficulties in providing smart service by utilizing IoT devices. Currently, many researchers are conducting researches on mobile-computing based smart service development and provisioning and network infrastructure for interconnected IoT devices. Still, there are some limitations on developing core technologies for IoT computing based smart service development. In order to remedy this situation, this thesis presents a reusable framework that provides unique and noble features which are required in developing advanced context-aware IoT applications.

• Convergence Security Journal
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• v.14 no.7
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• pp.75-84
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• 2014

The advancement in ubiquitous healthcare specifically in preventive healthcare can lead to longer life expectancy especially for the elderly patients. To aid in preventing premature loss of lives as well as lengthening life span, this research aims to implement the use of mobile and wireless sensor technology to improve the quality of life and lengthen life expectancy. The threats to privacy and security have received increasing attention as ubiquitous healthcare applications over the Internet become more prevalent, mobile and universal. Therefore, we propose Context-aware Service of U-Healthcare Application based Knowledge using Ontology in secure health information exchange. This research also applies ontology in secure information exchange to support knowledge base, context modeling, and context reasoning by applying the general application areas for ontologies to the domain of context in ubiquitous computing environments. This paper also demonstrates how knowledge base, context technologies, and mobile web services can help enhance the quality of services in preventive ubiquitous healthcare to elderly patients.

• The KIPS Transactions:PartA
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• v.16A no.5
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• pp.389-394
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• 2009

Lately the usage of multimedia equipment with small LCD displays is rapidly increasing. Although many people use devices like this, videos intended for TV or HDTV are sent to these mobile devices. Therefore cases where it is hard for the user to view the desired scenes are growing more frequent. Currently, most services simply reduce the size of the content to fit the screen when they offer it for mobile devices. However, especially with sports broadcasts, there are many areas that cannot be seen very well because it was simply reduced in size. We therefore consider this weakness and are researching how to let the user choose an area of interest and then sending it to the user in a way that fits the device. In this paper, we address the problem of video delivery and personalization. For the delivered video content, we suggest the UP-SAM User Personalized Context-Aware Service Adaptation Middleware) model that uses the video content description and MPEG-21 multimedia framework.

• IEMEK Journal of Embedded Systems and Applications
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• v.5 no.4
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• pp.195-205
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• 2010

The popularity of Smartphones makes new fields of applications based on location based service easily feasible with a new user interface called augmented reality (AR). It presents a particularly powerful user interface to context-aware computing environments. AR on Smartphones integrates virtual information into a person's physical environment by overlaying information on an image taken through Smartphone's camera and motion sensors. Mobile augmented reality systems provide this service without constraining the individual's whereabouts to a specially equipped area. This work presents an overview of handheld augmented reality focusing on applications with introducing the basic issues of them. For this purpose, an example system, Studierstube ES (embedded system), is cited, which introduces the most significant problems and various methods of solving them through the experience of converting existing PC-based AR system into handheld AR.