• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.8
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• pp.2797-2820
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• 2015

In order to accommodate huge number of antennas in a limited antenna size, a large scale antenna array is expected to have a three dimensional (3D) array structure. By using the Active Antenna Systems (AAS), the weights of the antenna elements arranged vertically could be configured adaptively. Then, a degree of freedom (DOF) in the vertical plane is provided for system design. So the three-dimension MIMO (3D MIMO) could be realized to solve the actual implementation problem of the massive MIMO. However, in 3D massive MIMO systems, the pilot contamination problem studied in 2D massive MIMO systems and the inter-cell interference as well as inter-vertical sector interference in 3D MIMO systems with vertical sectorization exist simultaneously, when the number of antenna is not large enough. This paper investigates the interference management towards the above challenges in 3D massive MIMO systems. Here, vertical sectorization based on vertical beamforming is included in the concerned systems. Firstly, a cooperative joint vertical beams adjustment and pilot assignment scheme is developed to improve the channel estimation precision of the uplink with pilots being reused across the vertical sectors. Secondly, a downlink interference coordination scheme by jointly controlling weight vectors and power of vertical beams is proposed, where the estimated channel state information is used in the optimization modelling, and the performance loss induced by pilot contamination could be compensated in some degree. Simulation results show that the proposed joint optimization algorithm with controllable vertical beams' weight vectors outperforms the method combining downtilts adjustment and power allocation.

• Journal of Digital Convergence
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• v.16 no.10
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• pp.115-123
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• 2018

This study explores unified service experience to boost O2O services. Previous studies on service management and marketing only focused on customer experience in offline stores, while prior works on information systems looked only at the experience of services in mobile applications. In this vein, this study took into accounts the characteristics of offline stores and the benefits of their mobile applications. Moreover, the final dependent variable was share of wallet to measure customer's expenditure within the category. The theoretical model was tested based on 219 consumers who frequently visit Starbucks and use its mobile application. PLS method was applied to analysis the research model and hypotheses. The analysis results showed that customer satisfaction about offline store is not significantly related to share of wallet, while satisfaction about mobile application plays a significant role in enhancing share of wallet. Hedonic and social benefits were found to have significant effects on satisfaction about mobile application. The analysis results help establish service marketing and strategies to enhance the unified customer experience of O2O service.

• Information Systems Review
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• v.5 no.2
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• pp.1-21
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• 2003

In this paper, we investigate industrial product intermediary's transformation strategy by exploiting advantages afforded by web based information technologies. Our motivation for this research stems from exploring intermediary's responding strategy to cope with supplier's threatening to disintermediation. From transaction cost perspective, internet can induce both the vertical quasi-integration (electronic hierarchy) and outsourcing (electronic market). Our rationale on directing one of these bi-directional movements is specified on intermediary's value adding on the supply chain. As such, we investigated supply chain performance, IT effects on customer's requirement of channel functions, and channel power structure. Propositions to suggest contingent e-transforming strategic alternatives are logically derived from dyadic nature of supply chain characteristics such as efficiency versus customer services, and supplier dominant versus easy replaceability of suppliers. The contingent e-transformation framework developed from intermediary's perspective is reviewed through longitudinal industry case analysis. Implications from the industry case analysis give us insights for the effectiveness of the framework to combine supply chain characteristics with intermediary's e-transformation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.468-471
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• 2010

MOST150, which has a higher bandwidth than of MOST25, appears to satisfy the demand for the automotive infotainment system and to increase the multimedia processing capacity, and the various technology applications are required for the accomplishment of MOST150 development. The MOST25 network technology is being restrictively equipped with some of the car models but the problems with bandwidth and compatibility has arisen. In order to solve this, the MOST150 technology has been developed and further research is being carried out to apply the technology to the automobile industry. Thus, for the effective process of the Ethernet traffic in the realization of MOST150/Ethernet Gateway for automobile, we, in the research, shall analyse the Management Mapping method, including the MOST150's Isochronous channel, the MOST Ethernet Packet channel, and etc. and study the efficient algorithm.

• Journal of Yeungnam Medical Science
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• v.39 no.4
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• pp.294-299
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• 2022

Background: Medical therapy is the standard treatment for uncomplicated acute type B aortic dissection (ATBAD), but there is little evidence of the need for intensive care unit (ICU) management. Therefore, we aimed to investigate the effects of ICU treatment on uncomplicated ATBAD. Methods: We retrospectively studied patients with uncomplicated ATBAD who were medically treated between January 2010 and July 2020. Patients were divided into short-term ICU stay (SIS) and long-term ICU stay (LIS) groups, according to a 48-hour cutoff of ICU stay duration. The incidence of pneumonia and delirium, rate of aortic events, hospital mortality, and survival rate were compared. Results: Fifty-five patients were treated for uncomplicated ATBAD (n=29 for SIS and n=26 for LIS). The incidence of pneumonia (3.6% vs. 7.7%) and delirium (14.3% vs. 34.6%) was higher in the LIS group than in the SIS group, but the differences were not statistically significant. The survival rates at 1, 3, and 5 years were not different between the two groups (SIS: 96.4%, 92.2%, and 75.5% vs. LIS: 96.2%, 88.0%, and 54.2%, respectively; p=0.102). Multivariate Cox regression analysis for aortic events showed that using a calcium channel blocker lowered the risk of aortic events. Conclusion: Long-term ICU treatment is unlikely to be necessary for the treatment of uncomplicated ATBAD. Active use of antihypertensive agents, such as calcium channel blockers, may be needed during the follow-up period.

• Knowledge Management Research
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• v.23 no.3
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• pp.285-311
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• 2022

In this study, based on the S-O-R framework, how individual's stimuli (i.e., video characteristics, YouTuber characteristics, real-time broadcasting characteristics of YouTube channel) form organisms (i.e., perceived usefulness, perceived pleasure, social presence), leading to viewers' responses (i.e., continuous watching intention, paid sponsorship intention) on real-time YouTube channels. For this purpose, a research model and hypotheses were constructed, and 369 questionnaire data collected from users of real-time broadcasting channel services on the YouTube platform were analyzed. Result findings confirmed that some video/YouTuber/real-time broadcasting characteristics significantly affect viewers' perceived usefulness/perceived pleasure/social presence, and further influence continuous watching/paid sponsorship intentions. Theoretical and practical implications of the findings are discussed in conclusion.

• Journal of Korea Society of Digital Industry and Information Management
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• v.19 no.2
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• pp.69-78
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• 2023

In this paper, IO+5G dedicated hardware is developed and an AI device communication system equipped with a 5G is designed and tested. The AI device communication system equipped with a 5G receives the collected real-time images and the information collected from the IoT sensor in real time is to analyze the information and generates the risk detection events in the AI processing board. The event generated in the AI processing board creates a 5G channel in the dedicated hardware equipped with IO+5G. The created 5G channel delivers event video to the control video server. The 5G based dongle network enables faster data collection and more precise data measurement compared to wireless LAN and 5G routers. As a result of the experiment in this paper, the average test result of the 5G dongle network is about 51% faster than the Wi-Fi average test result in downlink and about 40% faster in uplink. In addition, when comparing the test result with terms of the 5G rounter to be set to 80% upload and 20% download, the average test result is that the 5G dongle network is about 11.27% faster when downloading and about 17.93% faster when uploading. when comparing the test result with terms of the the router to be set to 60% upload and 40% download, the 5G dongle network is about 11.19% faster when downlinking and about 13.61% faster when uplinking. Therefore, in this paper it describes that the developed 5G dongle network can improve the results by collecting data and analyzing it faster than wireless LAN and 5G routers.

• Journal of the Society of Disaster Information
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• v.20 no.1
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• pp.1-12
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• 2024

Purpose: The objective of this study was to improve the tunnel maintenance and monitoring technology by establishing the maintenance, management, and monitoring standards for shield and TBM tunnels, which had been applied more in recent years. Method: This study comprehensively analyzed and compared the data and model simulations of Seoul Subway Lines 7 and 9 and Bundang Line, shield and TBM tunnels in South Korea, tunnels in France and Japan, and Channel Tunnel in the UK. Result: This study set maintenance and monitoring standards when there was no design estimate based on numerical analyses such as section design and section analysis regarding the maintenance and monitoring section of shield and TBM tunnels. Conclusion: It is necessary to determine safety by comprehensively considering not only each monitoring item but also the changing trend and correlation of all items and compensation of the tunnel.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.5
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• pp.983-990
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• 2024

Water quality management is an important element of aquaculture, and digitization of water quality information can be said to be the starting point of smart aquaculture. The complex water quality sensor is an IoT device that automatically measures arrow items such as pH, DO, water temperature, and salinity. However, due to the high price of the water quality sensor, it is economically burdensome to apply it to all aquaculture tanks, and it requires specialized knowledge to maintain them, making it difficult for small-scale aquaculture providers to apply them. In this paper, we propose a multi-channel complex water quality sensor to solve this problem. The proposed system is a device that measures the water quality of multiple tanks with a single sensor through valve control with a pump, thereby reducing sensor purchase costs for fish farms. In addition, we aimed to extend the service life of the sensor and improve the convenience of management by providing an automatic cleaning function using fresh water after measurement.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.3
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• pp.175-184
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• 2009

We are entering into a era of enterprise computing that is characterized by an emphasis on broadband convergence, knowledge s haring, and calm services. Some people refer to this as the "ubiquitous" computing because its focus is on a high degree of connectivity between a company and its customers, suppliers, and channel partners. Ubiquitous computing technology, "RF" stands for "radio frequency"; the "ID" means "identifer". The tag itself of a computer chip and an antenna. The shortest metaphor is that RFID is like a bar-code but is read with an electromagnetic field rather than by a laser beam. Much has already been written about the use of RFID. But there is no has written about the use of RFID in the convention industry. Therefore this study have specific objectives as follows. 1. To give details on the use of RFID in convention. 2. To introduces the key concepts behind RFID technology. 3. To identify advantage & disadvantage of RFID technology using a BEXCO CASE study. 4. To study on ubiquitous convention using RFID and effective operation methods such as entrance identification system, session management, machine management, CRM management, visitor management, and contents management. This results provide into the current status of ubiquitous computing technology in convention industries. Specific advantages by using ubiquitous computing technology(RFID) are one-stop differentiate service, wireless internet service, use of visitor management system, entrance by tag, and U-logistics. On other side, disadvantages are security, stabilization of RFID system, higher price of RFID tag, and commercial scale. Convention by using of RFID technology is currently at an early stage. Convention company as BEXCO need to have the capabilities to adapt, to customize, to commercialize, and to modify technology to suit our circumstances.