• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.6
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• pp.37-45
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• 2011

As vehicles become more intelligent, in-vehicle networking (IVN) systems such as controller area network (CAN) or FlexRay are essential for convenience and safety of drivers. To expand the applicability of IVN systems, attention is currently being focused on the communication between heterogeneous networks such as body networking and chassis networking systems. A gateway based on message mapping method was developed to interconnect FlexRay and CAN networks. However, this type of gateways has the following shortcomings. First, when a message ID was changed, the gateway must be reloaded with a new mapping table reflecting the change. Second, if the number of messages to be transferred between two networks increase, software complexity of gateway increases very rapidly. In order to overcome these disadvantages, this paper presents FlexRay-CAN gateway based on node mapping method. More specifically, this paper presents a node mapping based FlexRay-CAN gateway operation algorithm along with the experimental evaluation for ID change.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.5
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• pp.836-858
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• 2010

Web Services allow a user to integrate applications from different platforms and languages. Since mobile applications often run on heterogeneous platforms and conditions, Web Service becomes a popular solution for integrating with server applications. However, because of its verbosity, XML based SOAP messaging gives the possible overhead to the less powerful mobile devices. Based on the mobile client's behavior that it usually exchanges messages with Web Service continuously in a session, we design the Handheld Flexible Representation architecture. Our proposed architecture consists of three main components: optimizing message representation by using a data format language (Simple_DFDL), streaming communication channel to reduce latency and the Context-store to store context information of a session as well as redundant parts of the messages. In this paper, we focus on the Context-store and describe the architecture with the Context-store for improving the performance of mobile Web Service messaging. We verify our approach by conducting various evaluations and investigate the performance and scalability of the proposed architecture. The empirical results show that we save 40% of transit time between a client and a service by reducing the message size. In contrast to solutions for a single problem such as the compression or binarization, our architecture addresses the problem at a system level. Thus, by using the Context-store, we expect reliable recovery from the fault condition and enhancing interoperability as well as improving the messaging performance.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.31 no.3
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• pp.131-145
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• 2020

The microbiota-gut-brain axis, which refers to the bidirectional communication pathway between gut bacteria and the central nervous system, has a profound effect on important brain processes, from the synthesis of neurotransmitters to the modulation of complex behaviors such as sociability and anxiety. Previous studies have revealed that the gut microbiota is potentially related to not only gastrointestinal disturbances, but also social impairment and repetitive behavior-core symptoms of autism spectrum disorder (ASD). Although studies have been conducted to characterize the microbial composition in patients with ASD, the results are heterogeneous. Nevertheless, it is clear that there is a difference in the composition of the gut microbiota between ASD and typically developed individuals, and animal studies have repeatedly suggested that the gut microbiota plays an important role in ASD pathophysiology. This possibility is supported by abnormalities in metabolites produced by the gut microbiota and the association between altered immune responses and the gut microbiota observed in ASD patients. Based on these findings, various attempts have been made to use the microbiota in ASD treatment. The results reported to date suggest that microbiota-based therapies may be effective for ASD, but largescale, well-designed studies are needed to confirm this.

• Journal of information and communication convergence engineering
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• v.13 no.1
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• pp.7-14
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• 2015

In a multi-hop wireless network, connectivity is determined by the link that is established by the receiving signal strength computed by subtracting the path loss from the transmission power. Two path loss models are commonly used in research, namely two-ray ground and shadow fading, which determine the receiving signal strength and affect the link quality. Link quality is one of the key factors that affect network performance. In general, network performance improves with better link quality in a wireless network. In this study, we measure the network connectivity and performance in a shadow fading path loss model, and our observation shows that both are severely degraded in this path loss model. To improve network performance, we propose power control schemes utilizing link quality to identify the set of nodes required to adjust the transmission power in order to improve the network throughput in both homogeneous and heterogeneous multi-hop wireless networks. Numerical studies to evaluate the proposed schemes are presented and compared.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.652-655
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• 2017

As maritime information and communication technology has been developing and the demands for various kinds of application services has been increasing nowadays, the multi-band maritime networks combining available multiple radio networks has been introduced. We have previously proposed a multi-band network selection(MNS) system which operates in the middleware layer and selects the best available network seamlessly. In this paper we develop MNS server software, network interfaces, and application program. The functionalities of the MNS system, including updating network status, connecting to heterogeneous networks, and communicating in the best network are also verified via indoor test.

• ETRI Journal
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• v.36 no.6
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• pp.1051-1061
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• 2014

Technological advances made with the development of digital technology and the Internet have led to the emergence and evolution of digital convergence - the integration of media and communications. This, in turn, has led to the creation of the representative broadcast and communication convergence business model (IPTV service). This study examines the consumption patterns and behaviors of IPTV service customers and explores the process of their continuous use of the IPTV service, thereby endeavoring to contribute to the diffusion of digital convergence services. To survey customers' continuous use of the IPTV service, this study first designs a research framework based on an examination of the existing literature on satisfaction, loyalty, and so on. In addition, research is conducted on the switching barrier of the method of consolidating customers' adherence to a given IPTV service by increasing the burden on them, thereby developing a final research model with which to attempt yet another heterogeneous approach. This enables not only an analysis of the causal relationship with antecedent variables but also a measurement of the explanatory contribution of the antecedent variables' sub-variables.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.2
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• pp.101-106
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• 2010

Researches on air-ground robot cooperating system has been made recently. The cooperation among homogeneous robots focused on the architecture of the system, quality and influence of the communication. In contrast, the cooperation among heterogeneous robots such as aerial vehicle and ground vehicle robots has not been much handled. There are a couple of main points for those air-ground cooperating robots. One is using UAV (Unmanned Aerial Vehicle) as an extra sensor of UGV (Unmanned Ground Vehicle). This kind of application is usually used in situations such as guiding UGV to an appropriate path which could be better determined from the eye in the sky as UAV. The other main application of air-ground cooperating robot system is the localization. By combining sensor information from both UAV and UGV, the robot system as a whole can localize a target object or find features in the environment with better performance than UGV or UAV alone. Although these applications are recently studied in many different ways and devices, there are still a lot of possibilities in the field of air-ground cooperating robot systems. We introduce those research fields in this paper.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.2
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• pp.75-82
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• 2013

CAS (Conditional Access System) is a content protection solution that restricts access to the system according to user's standing and only authorized users can access the content in a pay-TV system. DCAS (Downloadable Conditional Access System) can download CAS client which is a software implemented via network. In recent years, research and development has been carried out on DCAS to solve the problems of compatibility among heterogeneous devices and internetworking with other services. In this paper, we propose key generation and management scheme for efficient interoperability among different DCASs based on PBC (Pairing Based Cryptography).

• The KIPS Transactions:PartC
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• v.13C no.7 s.110
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• pp.933-938
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• 2006

Different multimedia services over networks not only require different amounts of bandwidth but also have different Qualify of Service (QoS) requirements. For example, QoS guarantees for higher priority calls is an important issue in multimedia communication networks. In this paper, we develop an adaptive bandwidth management algorithm, which is able to provide QoS guarantees for higher priority calls while accommodating as many heterogeneous multimedia call connections as possible. Our scheme, based on reservation and bandwidth adaptation, manages bandwidth based on real time estimates of current network conditions. Simulation results indicate the superior performance of our scheme providing excellent trade off between contradictory requirements.

• Journal of Satellite, Information and Communications
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• v.6 no.2
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• pp.84-90
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• 2011

Handling paging mechanism at the IP layer (i.e., IP paging) makes it possible to support heterogeneous wireless access technologies, providing energy-saving and reduced location registration signaling overhead over IP-based mobile networks. However, IP paging may rather cause adverse effects under active communication environments because of significant paging signaling overhead and frequent paging delay. Therefore, in order to solve these problems, a cost-effective IP paging scheme is proposed in this paper, which enables a mobile node to perform selective registration and paging based on its profile information. Numerical results indicate that the proposed scheme has apparent potential to mitigate considerable paging signaling overhead and frequent paging delay in IP-based hierarchical mobile networks.