• Information and Communications Magazine
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• v.30 no.6
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• pp.3-12
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• 2013

와이파이(Wi-Fi) 기술은 무선 데이터 트래픽 폭증에 따라 사업자에게는 트래픽 우회, 이용자에게는 통신요금 부담 완화의 대안으로 중요성이 부각되고 있다. 이에 우리나라에서는 이동 통신사업자 중심으로 와이파이를 지속적으로 확충하여 세계에서 가장 많은 와이파이 존(zone)을 보유한 국가가 되었다. 그러나, 특정 장소에 와이파이를 중복적으로 구축함에 따라 투자 효율성과 서비스 품질이 저하되고, 서민 소외계층 이용시설에는 구축이 상대적으로 저조하다는 문제점도 상존하는 상황이다. 본 고에서는 우리나라의 와이파이를 효율적으로 확산하고자 3가지 개선방향을 제시하였다. 첫 번째는 경쟁구축 차별화에서 투자효율화 공동이용 전략으로의 전환이며, 두 번째는 수도권 도시 지역 중심에서 서민 소외계층 지역으로 확산시키는 것이다. 마지막으로 Legacy Wi-Fi에서 차세대 Wi-Fi로 전환하는 것을 주요 방향으로 제시하였고, 이러한 개선방향을 바탕으로 4가지 전략을 제시하였다. 첫 번째 전략은 PPP(Public Private Partnership) 방식의 공공와이파이(Public Wi-Fi) 구축으로, 전통시장, 복지시설 등 서민 소외계층이 주로 이용하며 와이파이 구축이 열악한 이용시설에 정부, 지자체, 통신사가 공동으로 투자하여 공공와이파이를 구축함으로써 정보격차를 해소시키는 것이다. 두 번째 전략은 통신사의 와이파이 개방을 통한 공용화로, 통신사가 공공장소에 기 구축한 와이파이의 개방을 유도함으로써 중복투자 및 서비스 품질 저하 방지 등 공용화를 통한 투자효율성을 제고하는 것이다. 세 번째 전략은 차세대 와이파이 선도도입을 통한 글로벌 경쟁력 강화로, LTE 등 이동통신 기술의 급속한 보급에 맞추어 무선랜 서비스의 경쟁력 확보를 위해 광대역화 광역화를 선도하고, 응용서비스 발굴 및 산업활성화를 유도하는 것이다. 마지막은 공공와이파이 인식제고로, 공공와이파이의 이용편의성과 홍보활동을 강화하는 것이다. 이러한 전략의 핵심은 공공와이파이 확산과 차세대 와이파이 선도 도입으로, 이를 통하여 통신복지를 실현하고, 산업활성화를 통한 국민행복을 실현시키는 것에 대하여 간략히 설명한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.5
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• pp.592-597
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• 2012

In this paper, a new small chip antenna for Wi-Fi application of the mobile handset is proposed. To miniaturize the chip antenna, the proposed antenna is designed to have the backside ground. The proposed antenna has S-shaped structure, which is designed on the LCP(Liquid Crystal Polymer) with ${\varepsilon}_r$=3.5. The size of the proposed antenna is $6.0mm{\times}2.5mm{\times}1.2mm$. The measured impedance bandwidth under a voltage standing wave ratio (VSWR) of 2 was 300 MHz(fractional bandwidth: 12.2 % 2.3~2.6 GHz), and peak gain is 1.42 dBi. The proposed antenna was designed using CST Microwave Studio commercial software tool. And the fabricated antenna is measured using a network analyzer and in anechoic chamber.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.2
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• pp.149-156
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• 2014

Floor number determination has attracted considerable attention because many applications require accurate floor number information for providing better localization services in multistory buildings. This paper describes a Wi-Fi-based, low-complexity floor number determination method for multistory buildings. In our scheme, with the exception of floor ID and received signal strength of each WAP, detailed information on the wireless access point (WAP) coordinates is not needed. The multi-wall-floor model is used for the simulation and analysis. The simulation results show that the floor determination accuracy is nearly 100 given an adequate deployment density of WAPs on each floor. The results also show that the proposed method provides a good estimate of floor number even when only a few WAPs are implemented on each floor. Specifically, the proposed method can work under extreme conditions, i.e., where there are no WAPs on a floor.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.6
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• pp.17-23
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• 2021

In the present study, a more compact dual-band slot antenna is newly proposed for Wi-Fi application. The proposed antenna is composed of rectangular two stepped slot with open end which can generate standing wave resonance at dual frequency bands and L-type microstrip feed line. The measured impedance bandwidths are 50 MHz(2.412 ~ 2.470 GHz) at low frequency band and 452 MHz(5.451 ~ 5.903 GHz) at high frequency band respectiviely. Furthermore its size of 14 × 21 mm² is reduced by 30% compared to the size of 20 × 21 mm² of a conventional similar compact slot antenna. It has the omni-directional radiation pattern characteristics of a typical dipole antenna on the H-Plane, so it is suitable for commercial wireless network applications such as Wi-Fi.

• Journal of the Korean Society for information Management
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• v.36 no.1
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• pp.295-313
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• 2019

The purpose of this study is to analyze library space use patterns through users' smartphone WiFi. This study is applied a method to detect WiFi signal of users' smartphone to analyze the in-library wayfinding of users. The library usage data were collected for four months in a library in Seoul, Korea. The results show that the average 37.9% of library users revisits the library the next month. Half of users stay under 7 minutes in the library. Users mainly visit the library between 2 and 3 o'clock, and few users visit the library after 5 pm on weekends. The floor moving pattern result shows that the co-visit rate between the third and fourth floor is higher than others, in that these two floors are mainly composed of book shelves. These results indicate that the method to detect the WiFi signal for spatial pattern analysis could be more effective than observation which was used in previous research. It, therefore, is expected that this method would be applied in other libraries to analyze and enhance the library space usage.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.1
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• pp.127-134
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• 2022

A modified folded monopole slot antenna for 3G WCDMA (1.91 ~ 2.17 GHz), 4G LTE (2.17 ~ 2.67 GHz), 3.5 GHz 5G (3.42 ~ 3.7 GHz) and Wi-Fi dual band (2.4 ~ 2.484 GHz / 5.15 ~ 5.825 GHz) was proposed for the first time. The proposed antenna is designed and fabricated on a FR-4 substrate with dielectric constant 4.3, thickness of 1.6 mm, and size of 35 × 60 mm². The measured impedance bandwidth of the proposed antenna is 2910 MHz(1.84 ~ 4.75 GHz) and 930 MHz(5.11 ~ 6.04 GHz), antenna gain in each frequency band is from 1.811 to 3.450 dBi. In particular, it was possible to obtain a commercially suitable omni-directional radiation pattern in all frequency bands of interest.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.6
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• pp.1063-1068
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• 2022

The modern society has become entry into the information age after the spread of Internet. In the information age, internet was developed from the wired access to the wireless Internet access. When a surge in demand for wireless Internet access, performance and speed of 2.4 and 5GHz band for Wi-Fi which leads to saturation of the communication was significantly fall. Accordingly, the communication of the 6GHz band for Wi-Fi 6E came to be interested. In this paper, we studied the design and fabrication of microstrip patch antenna to be used in wireless communication systems operating at around 6GHz band. To obtain antenna parameters such as patch size, inter patch space, antenna was simulated by HFSS(High Frequency Structure Simulator). From these parameters, slot microstrip patch antenna is fabricated using FR-4 of dielectric constant 4.4. The characteristics of fabricated patch type microstrip antenna were analyzed by network analyzer.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.2
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• pp.113-118
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• 2023

The WiFi fingerprint method for location estimation within the home has the advantage of using the existing infrastructure and estimating absolute coordinates, so many studies are being conducted. Existing studies have mainly focused on the study of localization algorithms, but the improvement of accuracy has reached its limits. However, since a wireless LAN receiver such as a smartphone cannot measure signals smaller than the reception sensitivity of radio signals, the position estimation error varies depending on the method of processing these values. In this paper, we proposed a method to increase the location estimation accuracy by pre-processing the received signal data of the measured wireless LAN router in various ways and applying it to the existing algorithm, and greatly improved accuracy was obtained. In addition, the preprocessed data was applied to the KNN method and the CNN method and the performance was compared.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.1
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• pp.78-101
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• 2017

High-quality industrial control is critical to ensuring production quality, reducing production costs, improving management levels and stabilizing equipment and long-term operations. WiFi-based Long Distance (WiLD) networks have been used as remote industrial control networks. Real-time performance is essential to industrial control. However, the original mechanism of WiLD networks does not minimize end-to-end delay and restricts improvement of real-time performance. In this paper, we propose two algorithms to obtain the transmitting/receiving phase cycle length for each node such that real time constraints can be satisfied and phase switching overhead can be minimized. The first algorithm is based on the branch and bound method, which identifies an optimal solution. The second is a fast heuristic algorithm. The experimental results show that the execution time of the algorithm based on branch and bound is less than that of the heuristic algorithm when the network is complex and that the performance of the heuristic algorithm is close to the optimal solution.

• Journal of Digital Contents Society
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• v.13 no.4
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• pp.477-482
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• 2012

The mVoIP service is the technology which focuses on the wireless data service as the IP network having the transmission rate of 100 Mbps classes on the high-speed middle of movement through the WiFi, WiBro and 3G mobile radio communication network, and etc. and is developed. Since 2010, the mVoIP (mobile VoIP) service shows the rapid growth due to 4G-LTE service seriously disclosed from July with the Smart phone and 2,011 it begins to be rapidly popularized. In this research, additionally the mVoIP service industry activation plan is presented with the trends of technology development including the chip-set/module/terminal, etc. based upon local and foreign market trend searchlight through the market demand analysis. The mVoIP service downloads App to the mobile apparatus and or can provide the service as the software through the WiFi network. Therefore, the change which is large in the products development aspect is to be have no. Expected to is being provided as the added service in the case of 4G-LTE as a matter of course, the service deployment where it is based on the market principle and demand needs is needed.