• Journal of Platform Technology
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• v.10 no.1
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• pp.11-19
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• 2022

In this paper, we propose a location-based service that the user's location is known by connection history to WI-FI AP installed in a facility known its location previously. The location-based service proposed in this paper manages job processing states of technicians who inspect and maintain the facility like elevator by using worker's location and arrival time information. The job scheduling management method proposed in this paper is based on previously scheduled arrival time and actual arrival time to a target facility. And we experimentally implemented the inspection and maintenance system of an elevator to show the feasibility of job schedule management based on location and arrival time information acquired from Wi-Fi AP connection history. Our experimental implementation shows that our proposed method is usefulness in the field of the inspection and maintenance of a facility.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.1
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• pp.59-63
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• 2022

In recent years, research on smart factory wireless mobile communication technology that wirelessly remotely controls utilities is being actively conducted. The Wi-SUN(Wireless Smart Utility Network) Alliance proposed Wi-SUN protocol structure suitable for building a platform such as a smart factory as a new wireless communication standardization standard based on EEE802.15.4g/e. It analyzes the performance of the IEEE802.15.4e CSL(Coordinated Sampled Listening) Mode MAC(Media Access Control) in terms of power consumption and looks at considerations for efficient operation. Although CSL-MAC can dramatically reduce power consumption at the receiving end in an asynchronous manner, it has been found that the transmitting end has a disadvantage in that power consumption occurs due to an excessive wake-up sequence.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.24-34
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• 2021

Estimation of the presence of people in real time is extremely useful for businesses in providing better services. Many companies and researchers have attempted various researches in order to count the number of floating population in specific space. Recently, as part of smart cities and digital twins, commercialization of measuring floating populations using Wi-Fi signals has become active in the public and private sectors. This paper explains the floating population measuring system from the perspective of general consumers(non-experts) who uses current population data. Specifically, it presents a method of estimating the floating population based on MAC-address values collected from smartphones. By distinguishing Real MAC-address and Random MAC-address values, we compare the estimated number of smartphone devices and the actual number of people caught on CCTV screens to evaluate the accuracy of the proposed method. And it appeared to have a similar correlation between the two datas. As a result, we present a method of estimating the floating population based on analyzing Wi-Fi Probe Requests

• Journal of Korean Public Health Nursing
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• v.3 no.2
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• pp.47-76
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• 1989

The objectives of this study was to analyze the major causes of decreasing utilization rate of health care institutios in pilot-project area of regional medical insurance, Kwang-hwa and Kun-wi country. After the implementation of medical insurance, utilization rate of health institutions turned out' to be lower than it was estimated, when the pilot-project of regional medical insurance was planned. It might be due to changes in inhabitant's behavioral attitude toward medical insurance. So this study was made to find measures for financial stability by increasing utilization rate of health care institutions and to be available for basic demand-supply program of medical care. The hypothesis of this study was as follows; First. there is difference in understanding health care institutions between Kun-wi and Kwang-hwa. Second. respondesnts of inquiry survey have exact knowledge of their past experience of treatment taken prior to enforcement of medical insurance, Questionaire survey was made as to each 700 household among total 11, 884 households in Kun-wi and 20,919 households in Kwang-hwa. In case of Kun-wi, 70% of inquired households (491) gave their answers. In Kwang-hwa, the number was 560 households (80% of inquireds). Dollected data was processed and analyzed by way of using SPSS batch system. To evaluate facto rs distribution aspects of data and to make comparison between two area, percentage and $X^2$ distribution were applied. The results were as follows; L The utilization rate of health care institutions in Kun-wi and Kwang-hwa was lower than it was estimated. when pilot-project of medical insurance was planned. 2. Prior to the implementation of medical insurance. inhabitants in two area chose the medical institutions considering such factors. First was medical care fee cheap. second in habitant's residence, Third was the institutions conveniently easy of access. 3. After the implementation of medical insurance. 26.1% of inqurieds in Kun-wi and 41.6% in Kwang-hwa, changed medical institutions. In case of Kwn-wi, from health care institution (p 0.05), and in case of Kwang-hwa, vice versa, from general medical institutions to health care institutions. 4. Evaluation by factors were made such as follows. Inquired gave high marks to following facts: In case of Kun-wi, general medical institutions were difficult of access and relation between patients: was not friendly, but burden of medical expenditure was light. Effects of treatment and facilities was good. In case of Kwang-hwa, inquired gave high evaluation marks to the follow ing facts; facilities of medical institutions was not good, but the burden of medical expenditure was light. 5. After the implementation of medical insurance, the services was evaluated as good, but inquired hopec for lessening the burden of medical expenditure. 6. In case of exact understanding of cost-sharing, the evaluation rate in Kwang-hwa was higher than that of Kun-wi (p < 0.005). And positive attitude toward necessity of medical insurance was also good in Kwang-hwa (p < 0.05). 7. In case of inquired's attitude toward medical institutions, Kwang-hwa showed positive response (p < 0.05) 8. In the case of comparison between general medical institution and health care institution, two area showed similar positive response; medical manpower, facilities of medical institutions and effest: of treatement was good. 9. In comprehensive evaluation of benefit-service; the general medical institution's positiveness was higher than that of health care institutions in Kun-wi. But in Kwang-hwa vice-versa. 10. If the medical expenditure of general medical institution and health care institutions was equal 77% of inquireds in Kun-wi and 59.1% in Kwang-hwa answered that they chose general medical insurance. Considering results above mentioned, the conclusion of this study was made as follows. 1. In Kwang-hwa county, where the understanding of health care institutions's was good, the utilization's of health care institutions was shown high. Therefore, in case of Kwang-hwa, betterment: should be made to induce increasing utilization rate for negative factors of health care institutions. 2. In case of Kun-wi, where the understanding of health care institutions was on the decrease, measures for changing such negative factors should be taken by way of strengthening public relations. And cases of Kwang-hwa should also be studied. 3. On the side of financial stabilization and establishing health care delivery system, primary health care should be available. Therefore, the major cause of inhabitant's avoiding health care institutions should be known. And measures for activating that institutions have to be taken. So, the facilities of health care institution have to be improved up to the level of clinic. And supportive measures for securing equipment and improving health care services should also be taken. It is necessary that strategy for public relations should be employed with policy considerations and supports.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.3A
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• pp.141-150
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• 2012

The WiMedia Alliance has specified a Distributed Medium Access Control (D-MAC) protocol based on UWB for high speed wireless home networks and WPANs. In this paper, firstly, a time slot reservation protocol for relay transmission is proposed. Furthermore, we propose a novel relay node selection algorithm adaptive to current UWB link transmission rate. The proposed relay node selection algorithm has compatibility with current WiMedia D-MAC standard and is executed at each device according to the SoQ as a QoS criterion.

• International Journal of Internet, Broadcasting and Communication
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• v.8 no.1
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• pp.53-63
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• 2016

This paper applies WiMedia UWB network into a wireless ship area network (WSAN) so as to support high-quality multimedia services on board and reliable instrument control information as well, since the need for mixed high-quality video traffic and shipboard control data traffic is essential for a high-cost valued digital ship. Thus, in this paper, prioritized contention access (PCA) and distributed reservation protocol (DRP) based on WiMedia UWB (ECMA-368) MAC protocols are combined and proposed to such mixed traffic environment, by varying the portions of superframe according to traffic type. It is shown that the proposed WiMedia UWB MAC protocol can provide reliable mixed video and shipboard control data traffic as well.

• International Journal of Internet, Broadcasting and Communication
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• v.8 no.4
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• pp.1-10
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• 2016

This paper considers WiMedia UWB network based wireless ship area network (WSAN) so as to support high-quality multimedia video data services and important shipboard control data. In this paper, prioritized contention access (PCA) and distributed reservation protocol (DRP) based on WiMedia UWB (ECMA-368) MAC protocols are combined and proposed to support mixed high-quality video traffic and shipboard control data traffic applying varying DRP and PCA data periods according to channel condition and link parameter ptimization. It is shown that the proposed dynmaic channel allocation of WiMedia UWB MAC protocol can provide reliable mixed video and shipboard control data traffic as well.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.2 no.4
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• pp.171-183
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• 2008

Nowadays, wireless packet data services are provided over Wireless MAN (WMAN) at a high data service rate, while 3G cellular networks provide wide-area coverage at a low data service rate. The integration of mobile WiMAX and 3G networks is essential, to serve users requiring both high-speed wireless access as well as wide-area connectivity. In this paper, we propose a cross-layer optimization scheme for a vertical handover between mobile WiMAX and 3G cellular networks. More specifically, L2 (layer 2) and L3 (layer 3) signaling messages for a vertical handover are analyzed and reordered/combined, to optimize the handover procedure. Extensive simulations using ns-2 demonstrate that the proposed scheme enhances the performance of a vertical handover between mobile WiMAX and 3G networks: low handover latency, high TCP throughput, and low UDP packet loss ratio.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.8
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• pp.1145-1152
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• 2010

Currently economical communication technologies are needed for high speed data exchange at sea. Wireless environments at sea require some special communication security solutions as well. In this paper, an augmented WiMAX MMR protocol is proposed as a solution of the broadband data communications and security at sea environments fundamentally with no base station.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.177-178
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• 2007

WiBro system provides reliable broadband communication services for mobile and portable subcribers. It allows interference-free reception under the conditions of multipath propagation and transmission errors. Thus, powerful channel-error correction ability Is required. CC/CTC Decoder which Is mandatory for WiBro system needs lots of computations for real-time operation. So, it is desired to design a CC/CTC Decoder having highly optimized hardware scheme for low latency operation under high data rates. This paper proposes an efficient CC/CTC Decoder structure for high data rate WiBro system. Particularly, the proposed CTC Decoder architecture reduces decoding delay by applying pipelining and multiple decoding blocks. Simulation results show that reduction of about 80% of processing time is enabled with the proposed CC/CTC Decoder despite of increase in are.