• Electronics and Telecommunications Trends
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• v.35 no.5
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• pp.43-56
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• 2020

The 5G system standardization body has been developing standard functions to provide ultra-high speed, ultra-high reliability, ultra-low latency, and ultra-connected services. In 3GPP Rel-16, which was recently completed, this system has begun to develop ultra-high reliability and ultra-low latency communication functions to support the vertical industry. It is expected that the trend in the adoption of mobile communication by the vertical industry will continue with the introduction of 5G. In this paper, we present the industrial Internet-of-Things (IIoT) service scenarios and requirements for the adoption of 5G systems by the vertical industry and the related standardization trend at present. In particular, we introduce the 5G time-sensitive networking standard technology, a core technology for realizing 5G-based smart factories, for IIoT services.

• Journal of Positioning, Navigation, and Timing
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• v.9 no.3
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• pp.191-205
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• 2020

Designing a new signal is essential in the development of a new Radio Navigation Satellite Service (RNSS) system. This paper introduces the signal design parameters and the figures of merit (FoMs) to be considered in designing a new RNSS signal, and then reviews their relationship in details. In addition, we show examples of the trade-off analysis between FoMs according to the signal design scenarios using an analytical simulation tool based on the relationship between the signal design parameters and the FoMs.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.10
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• pp.9-25
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• 1997

Personal Communication Networks will be composed of ATM-based broadband ISDN in the future. However, unlike the wired networks, many challenges will arise in the wireless communication service such as PCS. These callenges are frequency alteration of cell routing path, relatively very high error rate at transmission over the wireless interface, etc. Particularly, the alteration of cell routing path caused by handoff makes temporary deterioration of QoS. In this paper, the signaling flows of handoff scenarios which may occur on Personal Communication Networks are presented, and verified by Pertri-Net toolkit. In addition, the cell flow control scheme which minimizes the lagging gap between cells and maintains the cell sequence during handoff is proposed. The proposed scheme can be summarized as the differentiation of normal queue and handoff queue, and the cell flow control between these queues. For verification of the proposed scheme, we used two approaches, which are mathermatical manipulation and SLAM simulation.

• ETRI Journal
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• v.42 no.3
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• pp.446-458
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• 2020

In this study, an efficient scheme for hiding data directly in partially encrypted versions of high efficiency video coding (HEVC) videos is proposed. The content owner uses stream cipher to selectively encrypt some HEVC-CABAC bin strings in a format-compliant manner. Then, the data hider embeds the secret message into the encrypted HEVC videos using the specific coefficient modification technique. Consequently, it can be used in third-party computing environments (more generally, cloud computing). For security and privacy purposes, service providers cannot access the visual content of the host video. As the coefficient is only slightly modified, the quality of the decrypted video is satisfactory. The encrypted and marked bitstreams meet the requirements of format compatibility, and have the same bit rate. At the receiving end, data extraction can be performed in the encrypted domain or decrypted domain that can be adapted to different application scenarios. Several standard video sequences with different resolutions and contents have been used for experimental evaluation.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.225-231
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• 2006

The purpose of this study is to develop a promising hybrid structural health monitoring system for structural joints. For this propose, the combined use of vibration-based techniques and electro-mechanical impedance technique is employed. For the verification of the proposed health monitoring scheme, a series of damage scenarios are designed to simulate various situations at which the connection joints can experience during their service life. The obtained experimental results, modal parameters and electro-magnetic impedance signatures, are carefully analyzed to recognize the connecting states and the target damage locations. From the analysis. it is shown that the proposed hybrid health monitoring system is successful for acquiring global and local damage information on the structural joints.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.1
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• pp.68-86
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• 2015

Future wireless network aims to integrate different radio access networks (RANs) to provide a seamless access and service continuity. In this paper, a new resource denotation method is proposed in the WLAN and LTE heterogeneous networks based on a concept of spectral bandwidth mapping. This method simplifies the denotation of system resources and makes it possible to calculate system residual capacity, upon which an economic model-based network selection algorithm is designed in both under-loaded and over-loaded scenarios in the heterogeneous networks. The simulation results show that this algorithm achieves better performance than the utility function-based access selection (UFAS) method proposed in [12] in increasing system capacity and system revenue, achieving load balancing and reducing the new call blocking probability in the heterogeneous networks.

• Steel and Composite Structures
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• v.7 no.2
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• pp.105-118
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• 2007

On September $11^{th}$ 2001, the twin towers of the World Trade Center in New York City were struck by two hijacked airplanes. Despite severe local damage induced by the impact, the towers were able to sustain 102 and 56 minutes of the subsequent multi-storey fires before collapsing. The purpose of this study is to contribute to the understanding of the in-fire performance of composite trusses by examining the behaviour of the longer-span type used in the towers. It makes no attempt to be a forensic study of the actual events. Using the finite element package Vulcan, the structural mechanics of typical long-span composite floor trusses are explained, under a variety of scenarios, as the fire temperatures rise. Different boundary conditions, degrees of protection and loading are all covered, the results being presented mainly in the form of graphs of deflection and internal force of members against time.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.190-195
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• 2010

Vehicular ad hoc networks (VANETs) have a number of interesting applications to preserve road safety, notify users about changed road/traffic condition, handling post accident hazards and moreover service oriented applications to make the travel convenient to the drivers. Use of common information format for diverse applications enables the application developers to easily design flexible information dissemination system for new applications or add new features to existing application. This paper introduces a common information format for various applications in VANETs. The main goal of the paper is to design generalized distributed architectures for vehicular networks, which considers diverse application development scenarios and uses common information format. The proposed architectures enable the application developers to flexibly disseminate information to affected or interested user. In this paper, we have given a detail description of each component of the architectures and how they communicate with each other. In future, we will implement the proposed architecture using suitable simulator.

• Proceedings of the KSPS conference
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• 2006.11a
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• pp.120-123
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• 2006

The provision of personalized user interfaces for mobile devices is expected to be used for different devices with a wide variety of capabilities and interaction modalities. In this paper, we implemented a multimodal context-aware middleware incorporating XML-based languages such as XHTML, VoiceXML. SCXML uses parallel states to invoke both XHTML and VoiceXML contents as well as to gather composite multimodal inputs or synchronize inter-modalities through man-machine I/Os. We developed home networking service named "HomeN" based on our middleware framework. It demonstrates that users could maintain multimodal scenarios in a clear, concise and consistent manner under various user's interactions.

• Journal of Korean Society of Steel Construction
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• v.8 no.4 s.29
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• pp.43-50
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• 1996

Damage estimation of bridge structures has recently received considerable attention in the light of maintenance and retrofitting of existing structures under service loads and after natural disasters. A method for the damage assessment of bridge structures using a damage index technique is presented. The damage index is formulated for the changes of modal properties due to the change of the stiffness. In order to verify the method which is presented, numerical analysis is conducted on simple beam models. Each FE model is subjected to different damage scenarios, i.e., locations and degrees of damage. Results of numerical analysis indicate that the proposed method is capable of detecting inflicted damages using the eigenvalue of only first mode.