• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.175-181
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• 2014

With rapid growth of the wireless mobile computing network technologies, various mobile ad hoc network applications converged with other related technologies are rapidly disseminated nowadays. Vehicular Ad Hoc Networks are self-organizing mobile ad hoc networks that typically have moving vehicle nodes with high speeds and maintaining its topology very short with unstable communication links. Therefore, VANETs are very vulnerable for the malicious noise of sensors and anomalies of the nodes in the network system. In this paper, we propose an anomaly detection method by using big data techniques that efficiently identify malicious behaviors or noises of sensors and anomalies of vehicle node activities in these VANETs, and the performance of the proposed scheme is evaluated by a simulation study in terms of anomaly detection rate and false alarm rate for the threshold ${\epsilon}$.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.141-147
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• 2014

With the rapid development of major functions in a smartphone, many applications interacting with a smartphone are introduced and mobile applications converged with various related technologies are announced and rapidly disseminated recently. In this paper, we propose the design of a smart mobile application operated with devices like sensors in order to utilize various functions of the smartphone effectively. The mobile application proposed in this paper uses the bluetooth module of the smartphone, composes the wireless ad hoc network with various sensors around us, and collects bionic context information of the user in real time. The smart application designed and implemented in this paper is the sensor based healthy diet application that can fulfill healthy diet program by reflecting the user's sensed bionic context data in real time.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.275-280
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• 2009

Femtocells are viewed as a promising option for mobile operators to improve coverage and provide high-data-rate services in a cost-effective manner Femtocells can be used to serve indoor users, resulting in a powerful solution for ubiquitous indoor and outdoor coverage. TThe frequency accuracy and phase alignment is necessary for ensuring the quality of service (QoS) forapplications such as voice, real-time video, wireless hand-off, and data over a converged access medium at the femtocell. But, the GPS has some problem to be used at the femtocell, because it is difficult to set-up, depends on the satellite condition, and very expensive. The IEEE 1588 specification provides a low-cost means for clock synchronisation over a broadband Internet connection. The Time of Packet (ToP) specified in IEEE 1588 is able to synchronize distributed clocks with an accuracy of less than one microsecond in packet networks. However, the timing synchronization over packet switched networks is a difficult task because packet networks introduce large and highly variable packet delays. This paper proposes an enhanced filter algorithm to reduce ths packet delay variation effects and maintain ToP slave clock synchronization performance. The results are presented to demonstrate in the intra-networks and show the improved performance case when the efficient ToP filter algorithm is applied.

• Journal of Information Technology Services
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• v.16 no.2
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• pp.139-156
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• 2017

Since the global financial crisis of 2008, the continuous development and innovation in technology-related fields such as information and communications technology (ICT) are likely to swim against the recession. In this paradoxical situation, the necessity of financial innovation through ICT is on the rise. For this reason, the appearance of Fintech is more meaningful as a new converged industry with the potential to lead financial innovation. The term of Fintech is derived from combining 'Finance' and 'Technology.' In South Korea, one of the most popular types of Fintech is mobile payment. KakaoPay, which is the first mobile easy payment service in Korea, is a much more simplified type of mobile payment service than ones used in the past, and is provided by the most popular mobile messenger service in Korea, KakaoTalk. However, KakaoPay has few active users in spite of its many advantages, which include convenience, simplicity, and a powerful platform. Thus, the main purpose of this paper is to investigate influencing factors of user resistance on KakaoPay. In order to investigate specific factors, a research model is developed based on the unified understanding of user resistance put forth by Laumer and Eckhardt (2012). After gathering online survey data from KakaoTalk users, an empirical analysis is conducted to verify this research model. The results of this study give insights regarding user resistance factors in the Fintech sector, and by so doing, it is expected that the important factors of user resistance could help the diffusion of new services when new mobile payment services appear in the near future.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.6
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• pp.243-248
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• 2013

With rapid growth and fast diffusion of smartphone technologies, many users are deeply concerned about the smart applications and many mobile applications converged with various related technologies are rapidly disseminated. Especially, the convergence technologies like mobile apps that can establish the wireless ad hoc network between smartphone and other peripherals and exchange data are appear and progressed continuously. In this paper, we design and implement the smart app using bluetooth based wireless ad hoc sensor network that can connect smartphone with sensors and exchange data for various smart applications. The proposed smart application in this paper collects data obtained from more than 2 multi-sensors in real time and fulfills the decision making function by storing data at the database and analysing it. The smart application designed and implemented in this paper is the healthcare application that can analyze and evaluate the patient's health condition with sensing data from multi-sensors in real time through bluetooth module.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.1
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• pp.1-10
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• 2012

Mobility and quality of service (QoS) are becoming the more important issues in wireless communications. The traditional Internet service is expanding into new access media and applications. Since wireless communication services are accompanied by frequent handovers at remote sites, scalable and fast handover has become a prerequisite for ubiquitous communication. In this paper, the differentiated service (Diffserv) model is deployed in heterogeneous proxy mobile IPv6 (PMIPv6) networks to satisfy the QoS guaranteed service and fast handover requirements. The operational procedures for QoS guaranteed global roaming are presented. In addition, QoS management and handover cost evaluation schemes based on a mobile host's movement scope are proposed. This paper analyzes the reduction in handover delay in a network-based localized mobility management framework. We propose and analyze a PMIPv6 optimized with a global mobile access gateway (G-MAG), which is a network-based entity, to further improve the handover performance in terms of handover delay while maintaining minimal signaling overhead in the air interface among converged heterogeneous wireless networks. The handover signaling procedures with host-based MIPv6 are compared with network-based proxy MIPv6 (PMIPv6) and fast PMIPv6 assisted by G-MAG to show how much handover delay reduction can be achieved. Analytical results show that the handover delay is significantly reduced.

• Journal of the Korea Society of Computer and Information
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• v.24 no.1
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• pp.121-128
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• 2019

An Internet of Things(IoT) technology which provides intelligent services by combining context-awareness based intelligences, inter-communication is made of between things and things or between things and person through the network connected with intelligent things is spreading rapidly. Especially as this technology is converged into smart device, mobile, cloud, big data technologies, it is applied into various domains. Therefore, this is different from existing Web or Mobile Application. New types of IoT applications are emerging by adapting IoT into Web or mobile. Because IoT application is not only focused on software but also considering hardware or things aspect, there are limitations existing development process. Existing development processes don't consider analysis and design techniques considering both hardware and things. We propose not only a meta-model for development process which can support IoT application's development but also meta-models for main activities in this paper. Especially we define modeling elements by using UML's extension mechanisms, provide development process, and suggest design techniques how to apply those elements into IoT application's modeling phase. Because there are many types of IoT application's type, we propose an Android and Arduino-based on IoT application as a case study. We expect that proposed technique can be applied into many of various IoT application development and design with a form of flexible and extensible as well as main functionalities or elements are more concretely described. As a result, it brings IoT application's flexibility and the effect of quality improvement.

• Journal of Internet Computing and Services
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• v.10 no.2
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• pp.65-73
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• 2009

IEEE802.11 Wireless LAN(WLAN) is being widely used in public space such as airport, and increases the networking boundary in campus and enterprise, and it has lastly attracted considerable attention for mesh network and converged network with other 3G mobile communication networks. In WLAN, load balancing among Access Points(AP) is an important issue for efficient resource management or supporting the Quality of Service(QoS) of traffic, but most researches focused on the AP selection in network entry or roaming of Stations(STA). In this paper, we propose an AP-Initiated Flow Redirection(FR) for AP load balancing by monitoring AP's availability in the true sense. When the AP's resource becomes almost saturated, that is used more than a specific threshold, the AP queries the roaming possible neighbor APs about their availability and calculates the distribution of traffic load with statistical methods such as entropy or chi-square. Finally, the AP decides flows and new APs for redirection and performs it. Our simulation results show that our FR mechanism increases the performance in the various views.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.981-984
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• 2015

IoT is network evolved one more step than Mobile or Internet based on the existing wire communication and can interconnect all people, things, and virtual space at any time, anywhere. In particular, Internet of Things technology is expected to be converged on medical service such as elderly home care, chronic disease management, and treatment, and then it also contributes to savings and service quality of in the medical field and leads the paradigm or innovation of healthcare industry. In this study, we analyzed the IoT technology and application cases of medical service based on the IoT at home and abroad.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.5
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• pp.1912-1931
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• 2018

In future wireless network, user experience and energy efficiency will play more and more important roles in the communication systems compared to their roles at present. Quality of experience (QoE) and Energy Efficiency (EE) become the widely used metrics. In this paper, we study a combinatorial problem of QoE and EE and investigate a fair power allocation in heterogeneous networks. We first design a new metric, QoE-aware EE (QEE) to reflect the relationship of QoE and energy. Then, the concept of Utopia QEE is introduced, which is defined as the achievable maximum QEE in ideal conditions, for each user. Finally, we transform the power allocation process to an optimization of ratio of QEE and Utopia QEE and use invasive weed optimization (IWO) algorithm to solve the optimization problem. Numerical simulation results indicate that the proposed algorithm can get converged and efficiently improve the system energy efficiency and the QoE for each user.