• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.85-90
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• 2017

Indoor location-based services have been developed based on the Internet of Things technologies which measure and analyze users who are moving in their daily lives. These various indoor positioning technologies require separate hardware and have several disadvantages, such as a communication protocol which becomes complicated. Based on the fact that a reduction in signal strength occurs according to the distance due to the physical characteristics of the transmitted signal, RSSI technology that uses the received signal strength of the wireless signal used in this paper measures the strength of the transmitted signal and the intensity of the attenuated received signal and then calculates the distance between a transmitter and a receiver, which requires no separate costs and makes to implement simple measurements. It was applied calculating the value for the average RSSI and the RSSI filtering feedback. Filtering is used to reduce the error of the RSSI values that are measured at long distance.It was confirmed that the RSSI values through the average filtering and the RSSI values measured by setting the coefficient value of the feedback filtering to 0.5 were ranged from -61 dBm to - 52.5 dBm, which shows irregular and high values decrease slightly as much as about -2 dBm to -6 dBm as compared to general measurements.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.29 no.1
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• pp.125-152
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• 2018

This study examined users' awareness to establish futurity of libraries and to propose strategies in the era of the $4^{th}$ Industrial Revolution. For this purpose, the awareness survey was conducted of users, and the survey consisted of questions about the awareness of the $4^{th}$ Industrial Revolution, the current state of using technologies and devices of the $4^{th}$ Industrial Revolution, and the futurity of libraries of the $4^{th}$ Industrial Revolution. The results are as follows: First, users were interested in the $4^{th}$ industrial Revolution, but they thought that new technologies are poorly adopted in the libraries. Second, users were most frequently using mobile phone, QR code, and Beacon. Especially, mobile phone was a most frequently used device in the libraries. However, users were not satisfied with technologies and devices provided by the libraries. Third, users expected the $4^{th}$ Industrial Revolution have a positive influence on future of libraries, but they were worried about losses of opportunities and jobs. Forth, users agreed with necessity of new technologies of the $4^{th}$ Industrial Revolution for libraries services. They wanted application of the technologies, expecially, in online services. Ultimately, this study suggested some meaningful insights and strategies through comparative analysis of the above findings and librarians' awareness survey results.

• Journal of the Korean Society of Clothing and Textiles
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• v.40 no.6
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• pp.1045-1061
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• 2016

This study clarifies differences in attitudes toward the Omni-Channel service (Pintech service, Beacon service, and Click and Collect service) and fashion consumption behavior among four clusters grouped by level of technology readiness. An online survey was conducted; 572 individuals between 20 and 30 years of age were collected, but only 539 were used. Factor analysis, cluster analysis, descriptive statistics, ANOVA, and frequency analysis were adopted to analyze data using SPSS 20.0. The results are as follows. Technology readiness was divided into four factors: optimism, innovativeness, discomfort, and insecurity. Participants were divided into four groups according to four sub-factors of technology readiness: brave adopters, optimistic laggards, indifferent adopters, and critical adopters. These groups showed significant differences in attitudes toward the Omni-Channel service and fashion consumption behavior. Critical adopters and brave adopters recognized the value of the Omni-Channel service and had more positive attitudes toward it than other groups. Critical adopters also better perceived the risk of service with new technology that showed higher fashion innovativeness and monthly consumption of fashion products than other groups. We inferred that the indifferent adopters did not use the Omni-Channel service or services offered by fashion retailers as much as other groups because indifferent adopters were less interested in both the Omni-Channel service and fashion consumption behavior than other groups. Optimistic laggards viewed the Omni-Channel service optimistically, despite perceptions of high risks to accompanying it and a low intent to use it. The results of this study assisted in the formation of a theoretical framework of consumer behavior associated with the Omni-Channel, which is an emerging issue in research related to distribution. The results can help fashion industries that operate consumer-oriented marketing based on Omni-Channel strategies.

• Journal of Satellite, Information and Communications
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• v.9 no.2
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• pp.96-100
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• 2014

Recently, the management system of wastewater treatment facility has magnified due to the stringent regulations for the protection of the environment, and a sewage treatment plant efficiency and research of the car development are activated in large facilities or industrial park. however, the existing sewerage disposal system and specific water quality monitoring network reliability for real-time transmission of this building is insufficient. In this paper, we proposed a local wireless network design for sludge multi meter data collection and control for measuring the concentration of the sludge efficiently. Also, the collected data over the local wireless network to transmitted to the central monitoring system and accumulate the data in real time to calculate statistics is possible to monitor the status of the sewage treatment facilities. The proposed system uses a short-range wireless networks of IEEE 802.15.4 and configures an IEEE 802.11 network which can monitor real-time status in central system. Also, we install a sludge multimeter and communication network in sewage treatment facilities and confirm the usefulness of the proposed technique by demonstrating its effectiveness.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.11
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• pp.2218-2229
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• 2015

Recently Wi-Fi Alliance defined Wi-Fi direct, which can communicate through a direct connection between the mobile device anytime, anywhere. In Wi-Fi direct, all devices are categorized by group of owner (GO) and client. Since portability is emphasized in Wi-Fi direct devices, it is essential to control the energy consumption of a device very efficiently. In order to avoid unnecessary power consumed by GO, Wi-Fi direct standard defines two power management schemes: Opportunistic power saving scheme and Notice Of Absence (NOA) scheme. But, these two schemes do not consider the traffic pattern, so we cannot expect high energy efficiency. In this paper, we suggest an algorithm to enhance the energy efficiency of Wi-Fi direct power saving, considering the characteristics of multimedia video traffic. Proposed algorithm utilizes the statistical distribution for the size of video frames and adjusts the length of awake interval dynamically. Also, considering the inter-dependency among video frames, the proposed algorithm assigns priorities to video frames and ensures that a video frame with high priority is transmitted with higher probability than other frames with low priority. Simulation results shows that the proposed method outperforms the traditional NOA in terms with average delay and energy efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.3A
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• pp.209-216
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• 2005

This paper generally relates to the field of wireless local area networks(WLANs), and more particularly, to AP selection and association methods for the performance of a station. In these days, IEEE 802.11 Wireless LAN network is widely deployed and used as an emerging service to connect high-speed Internet in the public wireless environment. But, if there are many users in hot spot area, they suffer a severe decrease of performance. Thus it needs an association and access control mechanism especially when it is used in the public environment. In this paper, we suggest a selection and association method using Beacon or Probe Response frames based IEEE 802.11. Station selects AP using the information of the capacity area in a Beacon or a Probe Response frame. According to the present paper, an association method for a public WLAN service, which includes a WLAN user terminal and an AP for relaying WLAN communications to and from the user terminal, includes the steps of the user terminal asking the AP's states for access to a radio channel; and the station selects and associates with the AP According to the above-described selection in a high speed wireless Internet service based on public WLAN technologies that are currently in operations. Further, it is possible to improve the efficiency of network management.

• Journal of Advanced Navigation Technology
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• v.7 no.2
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• pp.149-155
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• 2003

This paper generally relates to the field of wireless local area networks(WLANs), and more particularly, to AP selection and association methods for the performance of a station. In these days, IEEE 802.11 Wireless LAN network is widely deployed and used as an emerging service to connect high-speed Internet in the public wireless environment. But, if there are many users in hot spot area, they suffer a severe decrease of performance. Thus it needs an association and access control mechanism especially when it is used in the public environment. In this paper, we suggest a selection and association method using Beacon or Probe Response frames based IEEE 802.11. Station selects AP using the information of the capacity area in a Beacon or a Probe Response frame. According to the present paper, an association method for a public WLAN service, which includes a WLAN user terminal and an AP for relaying WLAN communications to and from the user terminal, includes the steps of the user terminal asking the AP's states for access to a radio channel; and the station selects and associates with the AP. According to the above-described selection in a high speed wireless Internet service based on public WLAN technologies that are currently in operations. Further, it is possible to improve the efficiency of network management.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.6
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• pp.1147-1157
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• 2014

Intelligent transportation system (ITS) is realized through a highly ephemeral network, i.e. vehicular ad hoc network (VANET) which is on its way towards the deployment stage, thanks to the advancements in the automobile and communication technologies. However, it has not been successful, at least to date, to install the technology in the mass of vehicles due to security and privacy challenges. Besides, the users of such technology do not want to put their privacy at stake as a result of communication with peer vehicles or with the infrastructure. Therefore serious privacy measures should be taken before bringing this technology to the roads. To date, privacy issues in ephemeral networks in general and in VANET in particular, have been dealt with through various approaches. So far, multiple pseudonymous approach is the most prominent approach. However, recently it has been found out that even multiple pseudonyms cannot protect the privacy of the user and profilation is still possible even if different pseudonym is used with every message. Therefore, another privacy-aware mechanism is essential in vehicular networks. In this paper, we propose a novel identity exchange mechanism to preserve conditional privacy of the users in VANET. Users exchange their pseudonyms with neighbors and then use neighbors' pseudonyms in their own messages. To this end, our proposed scheme conditionally preserves the privacy where the senders of the message can be revoked by the authorities in case of any dispute.

• Journal of Navigation and Port Research
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• v.42 no.4
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• pp.245-252
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• 2018

A method of transmitting an alert signal in case of man-overboard (MOB) systems in a small fishing vessel navigating within coastal area is being operated as VHF-DSC equipment via a distress alert button and V-P ass Equipment via alert button or beacon separation. However, a small fishing vessel with a couple of crews on board is an inappropriate way to alert a man-overboard condition. However, internationally, MOB equipment using VHF-DSC, AIS, and Bluetooth technologies is used to transmit alert signals directly to the mother ship and other radio stations. In order to analyze the performance and technology of the MOB equipment operating in foreign countries, it was confirmed that the alarm signal can be received within a maximum of one nautical mile when the MOB device is on the water surface. An MOB device that meets domestic conditions needs to send an alarm signal to a station within the VHF communication range. However, in order to reduce the false alert signal, it is most appropriate to operate the VHF-DSC radio equipment installed on the ship remotely. Analysis of various technologies connecting the MOB and the VHF-DSC revealed that the Bluetooth system has advantages such as device miniaturization. When an emergency signal is transmitted from the MOB device, it can be received by a dedicated receiver and recognized through an external input terminal of the VHF-DSC equipment generating its own alarm. If the emergency situation cannot be processed at the mother ship, a distress alert is sent to all radio stations via VHF-DSC for response under emergencies faced by small fishing vessels.