• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.153-160
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• 2009

A hierarchical network between Mobile-WiMAX and WLAN systems is to make it possible to utilize wireless internet services including time sensitive applications such as VoIP, VOD, visual telephony etc. During the process of vertical handoff decision from Mobile-WiMAX to WLAN hotspot, vertical handoff delay causes user dissatisfaction because it doesn't provide the seamless wireless internet service. We make use of type of service (ToS) parameters in IEEE 802.16e specification as the criterion parameter of vertical handoff decision process in hierarchical Mobile-WiMAX/WLAN networks. In this paper, we propose the process of vertical handoff decision for seamless wireless internet service which is sensitive to time delay. If type of service is time sensitive application, the decision of vertical handoff is withdrawn until the service is terminated. In focus on user satisfaction, if the proposed traffic management strategy in hierarchical Mobile-WiMAX/WLAN networks is used, user will utilize seamless wireless internet services including time sensitive applications.

• The Journal of Korean Medicine
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• v.17 no.1 s.31
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• pp.266-279
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• 1996

To complement and develop the Orient Medical Bian Zheng treatmemt(韓方辨證施治), I have observed and analysed 68 persons who have recieved medical treatment because of the epigastric pain. Considering and analysed the Clinical Diagnosis(臨床診斷) and Clinical Bian Zheng(臨床辨證), Clinical Diagnosis(臨床診斷) and Gastroscopic Bian Zheng(微觀辨證), Clinical Bian Zheng(臨床辨證) and Gastroscopic Bian Zheng(微觀辨證), case history, age and sex, I have obtained the conclusion as follows. 1. The frequency of epigastric pain according to the classfication of Clinical Bian Zheng(臨床辨證) most occured in Gi Che Zheng(氣滯證), then in Huh Han Zheng(虛寒證). and least in Wi Youl Zheng. 2. There is no clear connection between the Clinical Bian Zheng(臨床辨證) and Clinical Diagnosis(臨床診斷). 3. The frequency of the epigastric pain according to Gastroscopic Bian Zheng(微觀辨證), mainly occurred in Wi youl Type(胃熱型), Wi Rac Jac Sang Type(胃絡灼傷滯型)and then occurred in Wi Han Type(胃寒型), and least occurred in Wi Rac A Che Type(胃絡瘀滯型) 4. Having observed the relation between the Gastroscopicin Bian Zheng(微觀辨證), and Clinical Diagnosis(臨床診斷) as pathological process, I have obtained the result that Wi Youl type(胃熱型) and Wi Rac Jac Sang Type(胃絡灼傷型) mainly occurred in Erosive Gastritis and Superficial Gastritis at the early stage, and Wi Rac A Che Type(胃絡瘀滯型) occurred in the whole stage among the Wuperficial Gastritis, Atro pic Gastritis, and Erosive Gastritis, Gastric Cancer, and the Wi Han Type(胃寒型) mainly occurred in Atropic Gastritis at the later stage. 5. The relation between Clinical Bian Zheng(臨床辨證) and Gastroscopic Bian Zheng(微觀辨證) do not coincide. 6. Observing the relation between the Clinical Bian Zheng(臨床辨證) and case history, Gi Che Zheng(氣滯證), Huh Han Zheng(虛寒證), Wi Youl Zheng(胃熱證) were commonly seen in the early stage of the case history, and Eum Huh Zheng(陰虛證) and Houl A Zheng(血瘀證) were seen in every stage. 7. Observing the relation between the Clinical Bian Zheng(臨床辨證) and age, Gi Che Type(氣滯型) was mostly seen in the thirties and other Bian Zheng(辨證) was seen after the middle 8. Observing the relation between the Clinical Bian Zheng(臨床辨證) and sex, Gi Che Type(氣滯型) was seen at high ratio in both sexes. 9. Observing the relation between the Gastroscopic Bian Zheng(微觀辨證) and case history Wi Han Type(胃寒證), Wi Youl Type(胃熱型), Wi Rac Jac Sang Type(胃絡灼傷型) were seen in the early stage of the case history Wi Rac A Che Type(胃絡瘀滯型) was mostly seen in the later stage. 10. There was no clear connection between the Gastroscopic Bian Zheng(微觀辨證) and age, sex. Although the examples were not sufficient, recipe regarding the partial variation state of stomach mucos together with Orient Medical Bian Zheng(韓方辨證) treatment seems to be useful in the effective treatment of Bi wi(脾胃) disease besides the epigastric pain.

• Korean System Dynamics Review
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• v.12 no.2
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• pp.37-67
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• 2011

This study first attempted to point out fundamental reasons behind the failure to have WiBro services off the saddle, investigating the previous studies, and second to screen the WiBro promotion policies after reviewing the major steps conducted thus far by the government. In order to put the screened policies in order by the importance, an AHP analysis was conducted targeting WiBro professionals in various fields such as government offices, universities, research institutes, and industry. One step further, causal loop diagramming on the system dynamics methodology was conducted to examine the dynamic structure of the WiBro market in holistic standpoint of view. Finally, a simulation model was developed based on the causal loop diagrams and the results of the AHP analysis in order to examine how various policy scenarios influence the growth of the WiBro market over time, and to compare the mix of policy options. Finally, the study attempted to draw some implications for WiBro vitalization.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.46-49
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• 2007

Multiple Antenna Technologies such as Multiple-Input Multiple-Output (MIMO) and Beamforming provide the increase of channel capacity and the reliability of wireless link. To obtain these advantages, WiBro, Mobile WiMAX and $4^{th}$ Generation System are employing multiple antenna technologies. There exist, however, many technical issues in considering the application of the technologies or the providing of services using them. In this paper, various technical topics are discussed and simple solutions are proposed. Beamforming has several technical issues which include coverage imbalance, difficulties in providing Multicast-Broadcast Service (MBS). In Addition, network planning is a critical point from a cell extension and initial network entry point of view. In case of MIMO, network deployment is discussed in that cellular data network such as WiBro has many repeaters. MIMO mode selection for maximizing the cell capacity is also covered.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5B
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• pp.334-343
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• 2008

In this work we propose a universal pricing machine, which incorporates a universal pricing framework for the future IEEE802.16 WiMAX service with multiple classes of service. A multimedia service is provided by a QoS provisioning scheme in the WiMAX network and universal pricing means that it can compute the price for any type of service in a unified framework. In the proposed pricing framework we incorporate multiple types of services such as the real time and nonreal time services that are supposed to be provided in the WiMAX network. To that purpose, let us first carry out an analysis on the current pricing scheme of Korean WiMAX service which incorporates only the data size. From that analysis we propose a new pricing scheme for the future WiMAX service that provides different service classes in the network. Via numerical experiment, we verify the implication of the work.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.6
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• pp.56-65
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• 2009

The single device that is combined more than one communication systems in shared band is called collocated system. In this paper, the collocated system is made by combination of Wi-Fi and WiMAX system. Performance of the collocated system is analysed by using two communication model, Collaborative and Non-Collaborative. To minimize the mutual interference between Wi-Fi and WiMAX system in collocated system, the circulator-based collocated system is proposed and analysed it's performance characteristics.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.12
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• pp.1890-1897
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• 2021

People counting is an important technology to provide application services such as smart home, smart building, smart car, etc. Due to the social distancing of COVID-19, the people counting technology attracted public attention. People counting system can be implemented in various ways such as camera, sensor, wireless, etc. according to service requirements. People counting system using WiFi AP uses WiFi CSI data that reflects multipath information. This technology is an effective solution implementing indoor with low cost. The conventional WiFi CSI-based people counting technologies have low accuracy that obstructs the high quality service. This paper proposes a deep learning people counting system based on WiFi CSI data. Data preprocessing using auto-encoder, data augmentation that transform WiFi CSI data, and a proposed deep learning model improve the accuracy of people counting. In the experimental result, the proposed approach shows 89.29% accuracy in 6 subjects.

• Journal of Satellite, Information and Communications
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• v.9 no.4
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• pp.16-19
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• 2014

In this paper, the beacon signals of WiFi doppler frequency detection based WiFi-AP was designed with the subcarrier between a transmitter and a receiver of WLAN(wireless LAN). We can use such signals to identify human moving as an antenna array and tracking of RF beam. This wireless security services with the combination of WiFi doppler frequency and adaptive beacon time signal was proposed for wireless detection and motion based services.

• Journal of IKEEE
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• v.25 no.2
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• pp.252-260
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• 2021

In this paper, a method of using Software Defined Radio (SDR) is proposed for improving the accuracy of identifying two kinds of signals as Wireless Fidelity (Wi-Fi) signal and Bluetooth signal at the same frequency band of 2.4 GHz based on the time-domain signal characteristic. An SDR device was set up for collecting transmitting signals from Wi-Fi access points (Wi-Fi) and mobile phones (Bluetooth). Different characteristics between Wi-Fi and Bluetooth signals were extracted from the measured result. The SDR device is programmed with a Wi-Fi and Bluetooth detection algorithm and a collision detection algorithm to detect and verify the Wi-Fi and Bluetooth signals based on collected IQ data. These methods are necessary for some applications like wireless communication optimization, Wi-Fi fingerprint localization, which helps to avoid interference and collision between two kinds of signals.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.4
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• pp.375-383
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• 2012

Together with the GPS-based approach, geolocation through mobile communication networks is a key technology for location-based service. Since the Mobile WiMAX system is considered as a candidate for fourth-generation mobile systems, it is important to investigate its location capability. The geolocation of Mobile WiMAX can be realized when the preamble symbols in the down-link channel are appropriately used for a TDOA (Time-Difference-of-Arrival) approach. However, the cellular structure of Mobile WiMAX inevitably generates co-channel interference, and it is difficult for the mobile terminal to acquire distance measurements from multiple base stations. Therefore, for geolocation via multilateration using the Mobile WiMAX network, it is very important to increase hearability. This paper proposes a geolocation method for Mobile WiMAX which employs interference cancellation and preamble signal overlapping for the enhancement of hearability. A novel interference cancellation strategy for complex-valued Mobile WiMAX signals is presented which has an iterative structure. Simulation results show that the proposed geolocation method provides the user's position with an accuracy of less than 20 m through the Mobile WiMAX cellular network if there is no multi-path or NLOS (None-Line-of-Sight).