• Journal of Power Electronics
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• v.16 no.3
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• pp.1012-1024
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• 2016

This study deals with an on-line software fault detection, localization, and system reconfiguration method for electrical system drives composed of three-phase AC/DC/AC converters and three-phase permanent magnet synchronous machine (PMSM) drives. Current sensor failure (outage), speed/position sensor loss (disconnection), and damaged DC-link voltage sensor are considered faults. The occurrence of these faults in PMSM drive systems degrades system performance and affects the safety, maintenance, and service continuity of the electrical system drives. The proposed method is based on the monitoring signals of "abc" currents, DC-link voltage, and rotor speed/position using a measurement chain. The listed signals are analyzed and evaluated with the generated residuals and threshold values obtained from a Sliding Mode Current-Speed-DC-link Voltage Observer (SMCSVO) to acquire an on-line fault decision. The novelty of the method is the faults diagnosis algorithm that combines the use of SMCSVO and adaptive thresholds; thus, the number of false alarms is reduced, and the reliability and robustness of the fault detection system are guaranteed. Furthermore, the proposed algorithm's performance is experimentally analyzed and tested in real time using a dSPACE DS 1104 digital signal processor board.

• Journal of Digital Convergence
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• v.15 no.4
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• pp.259-266
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• 2017

The massive traffic interferences in the wireless home IoT provides the reason for packet losses, and it degrades the QoS (Quality of Service) and throughput on the home network. This paper propose a new adaptive traffic interference control system, ATICS, for enhancing QoS and throughput for IoT services as detecting a traffic process and non-traffic process in the wireless home network. The proposed system control the traffic interferences as distinguishing the short-term traffic process and long-term traffic process by traffic characteristics in wireless home networks. The simulation results shows that the proposed scheme have more efficient traffic control performance than the other schemes.

• ETRI Journal
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• v.43 no.3
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• pp.447-458
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• 2021

The quality of experience (QoE) of video streaming is degraded by playback interruptions, which can be mitigated by the playout buffers of end users. To analyze the impact of playout buffer dynamics on the QoE of wireless adaptive hypertext transfer protocol (HTTP) progressive video, we model the playout buffer as a G/D/1 queue with an arbitrary packet arrival rate and deterministic service time. Because all video packets within a block must be available in the playout buffer before that block is decoded, playback interruption can occur even when the playout buffer is non-empty. We analyze the queue length evolution of the playout buffer using diffusion approximation. Closed-form expressions for user-perceived video quality are derived in terms of the buffering delay, playback duration, and interruption probability for an infinite buffer size, the packet loss probability and re-buffering probability for a finite buffer size. Simulation results verify our theoretical analysis and reveal that the impact of playout buffer dynamics on QoE is content dependent, which can contribute to the design of QoE-driven wireless adaptive HTTP progressive video management.

• Architectural research
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• v.24 no.2
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• pp.29-40
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• 2022

The transition from manufacturing to service-based economies in highly developed societies during the post-industrial period resulted in the decline of the industrial landscape, leaving it abandoned or underutilized. In pursuit of revitalizing the obsolete industrial space, innovative design techniques based on adaptive reuse are applied to retrofit modern functions to create a new cultural space and preserve the historical, symbolic, and cultural importance of the abandoned industrial facilities. Design considerations based on facade redesign have proven to be one of the most adopted techniques that can help in recreating a new function for the vacant industrial buildings and integrating them into the present-day urban fabric. This paper examines the facade renovation elements used for the adaptive reuse of 15 abandoned industrial buildings presently used as multi-purpose facilities in South Korea. Through a questionnaire survey, this study analyzes the respondents' preference for different facade renovation elements in the 15 sites according to age and gender. The study found that both genders showed similar preference patterns between most elements. But on some elements, females were keener and expressed a stronger opinion than males. There were much more females than males who perceived color and material as the most important exterior elements. The findings of this study can be used for the adaptive reuse of industrial buildings according to user preferences for different facade renovation elements.

• International journal of advanced smart convergence
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• v.3 no.2
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• pp.18-21
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• 2014

A control application requirements currently used is very low, such as packet loss rate, minimum delay on sensor networks with quality of service (QoS) requirements some packet delivery guarantee. This paper is the sampling period at the end of the actuator and sensor data transfer related to the Miss ratio for each source sensor node, use the controller and the internal ANFIS. The proposed scheme has the advantages of simplicity, scalability, and General. Simulation results of the proposed scheme can provide QoS support in WSANs.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.7 s.155
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• pp.1116-1125
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• 2006

This study investigated consumer satisfaction and dissatisfaction experiences in post-purchase product return process. As an exploratory research the study collected qualitative data of subjective consumer experiences using an open-ended questionnaire and identified and classified themes and patterns of satisfaction and dissatisfaction experiences. A total of 113 cases were categorized into satisfied experiences, unsatisfied experiences, and neutral experiences. Further, satisfied experiences were sub-categorized into kind sales associates, quick and easy return process, and services higher than expected based on sources of satisfaction in the return process while unsatisfied experiences were sub-classified into rejection of return, attitude of sales associates, and hassle of return process. In-store adaptive behaviors and intentions on future behaviors were also observed. The results indicated that service quality in the post-purchase service encounter and consumer expectation were important in determining satisfaction and dissatisfaction in the return process. Insights for research questions were proposed.

• Journal of Korea Multimedia Society
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• v.8 no.6
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• pp.814-826
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• 2005

The user-centric broadcasting environment includes the agent system and personalized broadcasting services for user-adaptive TV watching. In this paper, we propose broadcasting environment consisting of personalized broadcasting services and a multi-agent broadcasting system for the services. The proposed system employs the intelligent agent technology of the Foundation for Intelligent Physical Agents (FIPA) as well as metadata technology of MPEG-7 and TV-Anytime Forum (TVAF). To verify the usefulness of the proposed environment, we implemented a test-bed and demonstrated the proposed agent system with three services including intelligent user-information management service, information mobility service, and content retrieval service.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1168-1176
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• 2003

Internet telephony service is very cheap and very easy to introduce the value-added service than the POTS, but is difficult to the QoS of telephone service. The existing internet typically offers "best effort" services only, which do not make any commitment about delay, packet loss and jitter. This paper compensates the low quality of the speech for packet loss or delay using FEAPT algorithm in Internet phone. In the FEAPT algorithm, the receiver expands the received packet under resonable threshold, and hence compensates the QoS of speech.of speech.

• Journal of Communications and Networks
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• v.14 no.4
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• pp.461-466
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• 2012

Any future heterogeneous overlay network system must be able to support ubiquitous access across multiple wireless networks. To coordinate these diverse network environments, one challenging task is a call admission decision among different types of network. In this paper, we propose a new call admission control scheme to provide quality of service (QoS) while ensuring system efficiency. Based on the interplay between network structure and dynamics, we estimate the network's QoS level and adjust the service price adaptively with the aim of maximizing the network performance. A simulation shows that the proposed scheme can approximate an optimized solution while ensuring a well-balanced network performance in widely different network environments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.12
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• pp.5981-5997
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• 2017

Advanced Television Systems Committee (ATSC) produced ATSC 2.0 standard, which has been used for a HD/SD digital broadcasting service with MPEG-2 Transport Stream (TS) as a delivery protocol. Recently, users might want to consume multimedia services without being constrained by transport network. However, MPEG-2 TS is not suitable protocol for IP network. Thus, ATSC has enacted ATSC 3.0 standard, which is designed for a hybrid service through a conversion of both broadcasting and broadband channels. The ATSC 3.0 specifies delivery protocols as MPEG Media Transport (MMT) for a broadcasting environment and Dynamic Adaptive Streaming over HTTP (DASH) for a broadband. However, it seems difficult to combine broadcast and broadband for hybrid broadcasting, and it is difficult to synchronize media data between MMT and DASH. This paper suggests various new service scenarios to be brought up by a hybrid broadcasting, ATSC 3.0, and also proposes a stable mechanism for switching contents between different delivery protocols such as MMT and DASH.