• Journal of Digital Convergence
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• v.15 no.9
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• pp.223-230
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• 2017

In the current wireless Internet environment, using a mobile device to quickly access a web site is closely related to measuring the performance of a website. When accessing a website, the user has a long time to access the website and has no access to the website.In this case, the performance of the web site should be improved by measuring and analyzing the performance of the connection delay due to a problem of the web site.Among the performance measurement factors of Web sites, Web page loading time is a very important factor for a successful service business in the situation where most of e-commerce business is being developed as a web-based service.An open source tool was analyzed to analyze the performance of the e-commerce web page to present problems, software optimization methods and hardware optimization methods. Applying two optimization methods to suit the environment will enable stable and e-commerce websites.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.9
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• pp.1172-1179
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• 2020

With the establishment of the railway integrated radio network (LTE-R) environment, radio-based train control transmission and reception and various forms of service are provided. The smooth delivery of these services requires improved performance in a highly reliable and available wireless environment. This paper measured the LTE-R radio communication environment to improve radio communication performance of railway integrated wireless network reliability and availability, analyzed the results, and established the wireless environment model. Based on the built-up model, we also proposed an improved radio-access algorithm to control trains for improved reliability, suggesting a way to improve stability for handover that occur during open-air operation, and proposed an algorithm for frequency auto-heating to improve availability. For simulation, data were collected from the Korea Rail Network Authority (Daejeon), Manjong-Gangneung KTX route, which can measure the actual data of LTE-R wireless environment, and the results of the simulation show performance improvement through algorithm.

• IEMEK Journal of Embedded Systems and Applications
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• v.3 no.4
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• pp.218-228
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• 2008

The convergence of broadcasting and telecommunication services is being accelerated by broadband networks, digital broadcasting and Web2.0. This paper describes the definition and service characteristics of IPTV as a representative of broadcasting and telecommunication convergence services. Especially, the changes of infrastructure and technology for IPTV2.0 are addressed in terms of the service features of mobility, intelligence and participation. IPTV2.0 shall be characterized by the open IPTV service based on Web2.0 and the mobile IPTV service over the heterogeneous networks employing various wireless/wired access technologies. The IP Multimedia Subsystem (IMS) and Service Delivery Platform (SDP) technologies are increasingly considered to support the personalization and openness. The mobility management technology is being evolved to provide QoS-guaranteed mobile communication services to users at anytime and anywhere. IPTV2.0 services and platforms are also anticipated to be core components to achieve knowledge-based ubiquitous society. IPTV2.0 contents are required to be integrated with the enhanced metadata to efficiently support search, selection, convergence and delivery of the contents. Moreover, those contents shall be enhanced to provide the scalable services which is adaptable to the network status and user preferences. Therefore, the networking technologies for IPTV2.0 should tightly cooperate with application services and adaptive contents. Those technologies will be developed to construct the ubiquitous content service platform considering the evolution of networks and various converged services.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.8
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• pp.3852-3864
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• 2016

Patients' health data is very sensitive and the access to individual's health data should be strictly restricted. However, many data consumers may need to use the aggregated health data. For example, the insurance companies needs to use this data to setup the premium level for health insurances. Therefore, privacy-preserving data aggregation solutions for health data have both theoretical importance and application potentials. In this paper, we propose a privacy-preserving health data aggregation scheme using differential privacy. In our scheme, patients' health data are aggregated by the local healthcare center before it is used by data comsumers, and this prevents individual's data from being leaked. Moreover, compared with the existing schemes in the literature, our work enjoys two additional benefits: 1) it not only resists many well known attacks in the open wireless networks, but also achieves the resilience against the human-factor-aware differential aggregation attack; 2) no trusted third party is employed in our proposed scheme, hence it achieves the robustness property and it does not suffer the single point failure problem.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.11
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• pp.3751-3774
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• 2014

With the rapid development of wireless communication, the confliction between the scarce frequency resources and the low spectral efficiency caused by the stationary spectrum sharing strategies seriously restricts the evolution of the future mobile communication. For this purpose, cognitive radio (CR) emerges as one of the most promising inventions which can overcome the spectrum shortage. As the key technology and main objective of CR, spectrum sharing can make full use of the limited spectrum, alleviate the scarcity of frequency resources and improve the system utilities, playing thereby an important role in improving the system performance of cognitive radio networks (CRNs). In this survey, the spectrum sharing in CRNs is discussed in terms of the sharing process, mainstream sharing technologies and spectrum sharing models. In particular, comparisons of different spectrum sharing strategies are concluded, as well as that of different spectrum sensing schemes in sharing procedure. Moreover, some application examples of the spectrum sharing in CRNs, such as smart grid, public safety, cellular network and medical body area networks are also introduced. In addition, our previous related works are presented and the open research issues in the field of spectrum sharing are stated as well.

• 전자공학회논문지 IE
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• v.48 no.2
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• pp.52-60
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• 2011

RFID is method used on wireless system. However, this mechanism is not used for authentication and security. Therefore, it is very vulnerable to attacks such as dropping attacks and traffic attacks. the RFID Tags are of the limited nature due to environment factors and there is greater constraints in designing authentication protocol. If we do not RFID to secure corporate information and product all the information will be exposed. The attacker will break into the RFID system and stop the distribution system. So, this paper proposes a new authentication protocol which provides not only unlimited access to Tag&Reader and connection between Tag and Reader bet also provides authentication mechanism by defining the key distribution.

• The KIPS Transactions:PartC
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• v.16C no.2
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• pp.183-188
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• 2009

Wireless sensor networks will be broadly deployed in the real world and widely utilized for various applications. A prerequisite for secure communication among the sensor nodes is that the nodes should share a session key to bootstrap their trust relationship. The open problems are how to verify the identity of communicating nodes and how to minimize any information about the keys disclosed to the other side during key agreement. At any rate, any one of the existing schemes cannot perfectly solve these problems due to some drawbacks. Accordingly, we propose a new pre-distribution scheme with the following merits. First, it supports authentication services. Second, each node can only find some indices of key spaces that are shared with the other side, without revealing unshared key information. Lastly, it substantially improves resilience of network against node capture. Performance and security analyses have proven that our scheme is suitable for sensor networks in terms of performance and security aspects.

• International Journal of Computer Science & Network Security
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• v.22 no.3
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• pp.303-311
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• 2022

The tremendous growth of the Internet of things is unbelievable. Many IoT devices have emerged on the market over the last decade. This has made our everyday life easier inside our homes. The technology used at home has changed significantly over the past several decades, leading to what is known today as the smart home. However, this growth has also brought new challenges to our home security and privacy. With the smart home becoming more mainstream, cybersecurity issues have become a fundamental concern. The smart home is an environment where heterogeneous devices and appliances are interconnected through the Internet of Things (IoT) to provide smart services to residents. These services include home climate control, energy management, video on demand, music on-demand, remote healthcare, remote control, and other similar services in a ubiquitous manner. Smart home devices can be controlled via the Internet using smartphones. However, connecting smart home appliances to wireless networks and the Internet makes individuals vulnerable to malicious attacks. Remote access within the same environment or over the Internet requires an effective access control mechanism. This paper intends to shed light on how smart home devices are working as well as the type of security and privacy threats of the smart home. It also illustrated the types of authentication methods that can be used with smart home devices. In addition, a comparison of Smart home IoT-based security protocols was presented along with a security countermeasure that can be used in a smart home environment. Finally, a few open problems were mentioned as future research directions for researchers.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.10-18
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• 2013

With advancing of mobile communication services and commercializing of VoLTE (Voice of LTE), it is getting to pay attention on QoS of VoLTE. This paper proposes an integrated E-model in which some factors influenced to service quality of VoIP and VoLTE based voice communication system are considered in calculating the voice quality of Wideband Codec. The model aims to calculate R value which reflects the situations of access network, network characteristics, terminals' usage and mobility. We mainly deal with the integrated E-model's structure, related algorithms and optimal parameters for VoLTE. Some experiments show that the voice quality difference between VoIP and VoiceChecker, and VoLTE and POLQA, is below 10%. With the proposed model, we can calculate the voice quality by making use of the factors directly affected to service quality and the environment of VoLTE terminal and network. As a result, we can estimate the service quality in advance, without measuring it in real wireless environment.

• Journal of The Korea Institute of Healthcare Architecture
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• v.20 no.4
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• pp.49-56
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• 2014

Purpose : This purpose of this study is to make a better public hospital patient room to reflect the views of the patient. Methods: Survey to examine patient experience on healing environment in public hospital have been conducted for the data collection. 229 open-ended answers have been analysed statistically by MS Excel program. Results : 1) If there is no toilet space in the six-patient room, installation of toilet in the patient room is necessary. 2) The most Frequently used patient furnitures are necessary to accomodate the patients needs. Depending on the patient condition, installation of a portable or fixed the room furniture for the convenience to the using furniture. 3) According to the flow of modern times, wireless internet access is required to install of expand the space. Also be used to establish a regulations of internet space. 4) To create healing environment infection free environment should be provided. 5) Need for improvements of patient room for relatives of patient. It is necessary to secure a comfortable space to stay. 6) Separation is needed among the patients through therapeutic classification. Implication : In order to provide a better patient room environment, it is necessary to reflect the patient's opinion.