• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.6
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• pp.2534-2553
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• 2018

Source routing is the routing scheme that arranges the whole path from source to target at the origin node that may suit the requirements from the upper layer applications' perspective. The centralized control in SDN (Software-Defined Networking) networks enables the awareness of the global topology at the controller. Therefore, augmented source routing schemes can be designed to achieve various purposes. This paper proposes a source routing scheme that conducts the top-K QoS-aware paths discovery in SDN. First, the novel non-invasive QoS over LLDP scheme is designed to collect QoS information based on LLDP in a piggyback fashion. Then, variations of the KSP (K Shortest Paths) algorithm are derived to find the unconstrained/constrained top-K ranked paths with regard to individual/overall path costs, reflecting the Quality of Service. The experiment results show that the proposed scheme can efficiently collect the QoS information and find the top-K paths. Also, the performance of our scheme is applicable in QoS-sensitive application scenarios compared with previous works.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.9 s.112
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• pp.874-882
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• 2006

We surveyed the international and national spectrum & technical standardization trends of extremely adaptive frequency bands $57\sim64GHz$ that can provide 1 Gbps bit-rate ultra broadband service in above 30 GHz millimeter waves, and analyzed service scenarios and the characteristics of these bands, As a result of these analysises, 1 Gbps ASK channel bandwidth needs 2.5 GHz and total bandwidth calculated 7 GHz for dual FDD. finally, we proposed the nationally suitable allocation plan of millimeter wave bands $57\sim64GHz$.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.2
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• pp.301-307
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• 2018

Unmanned Aerial Vehicles (i.e., drone) are gaining a lot of interest from a wide range of application domains such as infrastructure monitoring and parcel delivery service. In those service scenarios, multiple UAVs are involved and should be reliably operated by so-called UAV management system. For that, we propose oneM2M standard based UAV management and control system which is specifically targeted at traffic management of low-altitude UAVs. In this paper, we include oneM2M platform architecture and its implementation for UAV management system in conjunction with UAV interworking procedure.

• Journal of the Korean Society for information Management
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• v.34 no.4
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• pp.33-57
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• 2017

This study aims to introduce an emerging prescriptive analytics method and suggest its efficient application to a category-based service system. Prescriptive analytics method provides the whole process of analysis and available alternatives as well as the results of analysis. To simulate the process of optimization, large scale journal articles have been collected and categorized by classification scheme. In the process of applying the concept of prescriptive analytics to a real system, we have fused a dynamic automatic-categorization method for large scale documents and intellectual structure analysis method for scholarly subject fields. The test result shows that some optimized scenarios can be generated efficiently and utilized effectively for reorganizing the classification-based service system.

• Journal of Information Technology Services
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• v.11 no.3
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• pp.241-255
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• 2012

Recently, smart home environments which provide complex services through smart appliances are becoming realized, due to the advances in connected devices and network technologies. Current smart home environments are mostly restricted, because of difficultly of integration of heterogeneous smart appliances. Therefore radical service integration is impracticable. In this paper, we analyze and implement Machine-to-Machine (M2M) standards which are established by European Telecommunications Standards Institute (ETSI) for integrating heterogeneous devices and services. Smart Home is one of the areas covered by ETSI M2M standards, however these standards are just standardized, so adaption and assessment in smart home are not proved yet. Therefore, this paper analyze ETSI M2M standards by focusing the data transport model and evaluate by selecting the most commonly used smart home scenarios and by implementing ETSI M2M standards compatible smart metering system. In some points ETSI M2M standards are not efficient because of its complexity of structure, however ETSI M2M provides sophisticated features for integrating M2M which are appropriate to adopt diverse smart home environments.

• Journal of Information Technology Services
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• v.19 no.3
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• pp.151-163
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• 2020

This paper describes a study on the FRACAS(Failure Reporting Analysis and Corrective Action System)-based dependability control platform for domestic urban railway trains. There are more demands for the verification of the dependability of trains as it becomes a regulation for train manufacturers to verify the dependability recently. Train manufacturers as well as railway operators need a effective FRACAS solution to perform the verification of the dependability. Yet current FRACAS solutions have limitations to support the verification processes effectively. This paper addresses the issues of current FRACAS solutions and suggests a FRACAS framework designed for the domestic urban railway trains. Service failure scenarios are standardized using the proposed availability model to implement a more user-friendly and reliable platform. A new FRACAS-based platform for the dependability control (SCARF^®) has been developed to implement the suggested framework. The detail interfaces and functions of the platform are explained. The SCARF^® platform is expected to engage the increasing demands for the dependability control successfully enhancing the reliability, maintainability, availability and safety of domestic urban railway trains eventually.

• Journal of information and communication convergence engineering
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• v.6 no.2
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• pp.122-128
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• 2008

Multiprocessor architectures and platforms, such as, a multiprocessor system on chip (MPSoC) recently introduced to extend the applicability of the Moore's law, depend upon concurrency and synchronization in both software and hardware to enhance design productivity and system performance. With the rapidly approaching billion transistors era, some of the main problem in deep sub-micron technologies characterized by gate lengths in the range of 60-90 nm will arise from non scalable wire delays, errors in signal integrity and non-synchronized communication. These problems may be addressed by the use of Network on Chip (NOC) architecture for future System-on-Chip (SoC). We have modeled a concurrent architecture for a customizable and scalable NOC in a system level modeling environment using MLDesigner (from MLD Inc.). Varying network loads under various traffic scenarios were applied to obtain realistic performance metrics. We provide the simulation results for latency as a function of the buffer size. We have abstracted the area results for NOC components from its FPGA implementation. Modeled NOC architecture supports three different levels of quality-of-service (QoS).

• Journal of Communications and Networks
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• v.12 no.4
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• pp.334-345
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• 2010

In this paper, we study optimal tradeoffs of achievable throughput versus consumed power in wireless ad-hoc networks formed by a collection of multiple antenna nodes. Relying on adaptive modulation and/or dynamic channel coding rate allocation techniques for multiple antenna systems, we examine the maximization of throughput under power constraints as well as the minimization of transmission power under throughput constraints. In our examination, we also consider the impacts of enforcing quality of service requirements expressed in the form of channel coding block loss constraints. In order to properly model temporally correlated loss observed in fading wireless channels, we propose the use of finite-state Markov chains. Details of fading statistics of signal-to-interference-noise ratio, an important indicator of transmission quality, are presented. Further, we objectively inspect complexity versus accuracy tradeoff of solving our proposed optimization problems at a global as oppose to a local topology level. Our numerical simulations profile and compare the performance of a variety of scenarios for a number of sample network topologies.

• Journal of Communications and Networks
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• v.10 no.3
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• pp.258-267
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• 2008

In this paper, we examine what changes the next-generation wireless communication systems will experience in terms of the technologies, services, and networks and, based on that, we investigate how the inter-cell interference management should evolve in various aspects. We identify that the main driving forces of the future changes involve the data-centric services, new dynamic service scenarios, all-IP core access networks, new physical-layer technologies, and heavy upload traffic. We establish that in order to cope with the changes, the next-generation inter-cell interference management should evolve to 1) set the objective of providing a maximal data rate, 2) take the form of joint management of power allocation and user scheduling, 3) operate in a fully distributed manner, 4) handle the time-varying channel conditions in mobile environment, 5) deal with the changes in interference mechanism triggered by the new physical-layer technologies, and 6) increase the spectral efficiency while avoiding centralized coordination of resource allocation of the users in the uplink channel.

• IEMEK Journal of Embedded Systems and Applications
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• v.10 no.3
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• pp.129-137
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• 2015

Various personalized services are provided based on user context these days, and IoT(Internet of Things) devices provides effective ways to collect user context. For example, user's activity such as walking steps, calories, and sleeping hours can be collected using smart activity tracker. Smart scale can sense change of user's weight or body fat percentage. However, these services are independent to each other and not easy to make them collaborate. Many standard bodies are working on the documents for this issue, but due to diversity of IoT use case scenarios, it seems that multiple IoT technologies co-exist for the time being. This paper propose a framework to collaborate heterogeneous IoT services. The proposed framework provides methods to build application for heterogeneous IoT devices and user context management in more intuitive way using HTTP. To improve compatibility and usability, gathered user contexts are based on MPEG-UD. Implementation of framework and service with real-world devices are also presented.