• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.99-103
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• 2009

Recently, as wired and wireless communication services have rapidly developed and multimodal mobile devices which have various characteristics have widely spread, the need for new convergence services increases. The growing population of VoIP technologies and the high communication expense yield that the market of IP based telephony such as WiFi phone and IP phone is substituted for one of the conventional PSTN telephony. With the help of this trend, the wireline network operators desire to find a market in mobile networks. Therefore, they focus on Fixed Mobile Convergence (FMC) service as one of the key factors to accomplish this goal. FMC services are able to provide the mobility of voice services between circuit switched and packet switched networks. IP Multimedia Subsystem (IMS) based Voice Call Continuity (VCC) is one of the schemes to embody FMC services. As Application Server (AS) which has this VCC function provides seamless handover of services between heterogeneous networks, FMC subscribers can communicate seamlessly with others m WiFi domain and COMA domain using WiFi-COMA dual phone. Most of enterprises have already introduced IP network infrastructure and IP-PBX (Private Branch eXchange) for telephony. However, the problems of high communication cost and work inefficiency due to frequent outside jobs or business trips have remained. In order to solve these problems, demands for enterprise FMC services increase. In this paper, we introduce a new IP-PBX based VCC model that can provide seamless handover of voice services between WiFi and COMA networks for enterprise users and we investigate some interworking and security issues between Soft Switch (SSW) and IMS, or between IMSs. In addition, we introduce a new service that can provide the continuity of voice sessions as well as video sessions using Multimedia Session Continuity (MMSC) technology which has evolved from VCC. This service is expected to be one of the next-generation personalized services based on user's context.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.298-300
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• 2015

Beacon is a signal device, which mainly used to support the safety of the locate and operation of a watercraft and aircraft. Recently, the IT sector BLE (Bluetooth Low Energy) also made possible to operate with less energy over several months using a beacon standards are applied. In addition, the location-based services and technologies using BLE Beacon has attracted attention. However, there is the problem that by using only the position location Beacon devices when high error rate can be measured accurate position. Therefore, in this paper, combines WiFi and Beacon based on Smartphone. Also propose an indoor positioning algorithm reduces the error rate of the position location value.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.2
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• pp.243-248
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• 2012

In this paper we simulate the capacity of VOIP calls through WiFi network by computer simulations using OPNET modeler. The results show that sudden quality degradations occur on all VoIP calls when the number of call of an AP(Access Point) increases beyond a specific value. The reason of the quality degradation was turned out to be the queueing delay at the down link of AP. Under the IEEE 802.11b environments, the maximum number of VoIP calls of an AP maintaining the required voice quality (MOS > 2.5), was evaluated as 5, 12, and 27 when we use G.711, G.729a, and G.729a VAD codec, respectively.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.360-363
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• 2008

현재 통신 시장의 상황은 유무선 통신서비스 시장의 포화, 이동통신 시장의 기존 유선전화 규모 초과, 그리고 유선통신의 서비스 사업자의 영역 확대 도모 등을 특징으로 한다. 유무선 통합 (Fixed Mobile Convergence, FMC) 서비스는 유선통신 사업자를 중심으로 한 비즈니스 모델로 사용자에게 유무선 통신망 종류에 상관없이 일관되고 끊김없는 서비스를 제공하는 것을 목표로 한다. 이동통신망까지 확대하여 고객 기반을 유지하고자 하는 유선사업자들은 FMC 서비스 중 하나의 방안으로 IMS (IP Multimedia Subsystems) 기반의 VCC(Voice Call Continuity) 기능에 주목하고 있다. VCC AS(Application Server)는 이종망 (WiFi-CDMA)간 Seamless 핸드오버기능을 수행하므로, WiFi 와 CDMA를 지원할 수 있는 듀얼단말을 이용하여 사용자가 WiFi 서비스 지역과 CDMA 서비스 지역간 이동시에도 Seamless 한 음성서비스를 제공한다. 이에 본 논문은 IMS/VCC 기반으로 음성 seamless 핸드오버 적용 사례(시범서비스)를 중심으로 유무선 통신사업자 상호 Win-Win을 추구할 수 있는 LG데이콤 특화 VCC 모델을 제시한다. 그리고 LG데이콤이 추구하는 차세대 서비스인 사용자 context 기반의 개인화된 서비스 제공을 위한 IMS 기반 통합 프로파일/인증/과금 연구 동향에 대해 간략히 소개한다.

• 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.

• Journal of information and communication convergence engineering
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• v.8 no.6
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• pp.665-670
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• 2010

This paper suggests the vehicle remote control on the basis of Smart Phone. In general, most smart phone is mounted with G-sensor to control the motion. G-sensor is able to control several directions and movements of velocity along with X, Y, and Z axis. To access remote location and data system, we can also utilize Wi-Fi communication as well as bluetooth communication. In this study, we propose the scheme that is the car management application by remote control via real-time monitoring on mobile device for user convenience.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.4 no.4
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• pp.272-277
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• 2011

LBS(Location Based Service) is one of the most important killer App. in the Smart-phone Era. The Smart-phone provide basically location informations using GPS, Wi-Fi AP, 3G ID as a location determination technology to supply LBS. Also it can use maps such as Google map and Daum map with Open API. Therefore, Smart-phone is regarded as the best platform to develop location based applications. In my paper, a location based smart-phone App., that is, "Real-Race App." is designed and implemented for applying events and marketing.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.1
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• pp.41-47
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• 2013

This letter describes a dual-band compact monopole antenna with two branches for Wi-Fi applications. The proposed antenna is based on a planar monopole design, and composed of two branches of radiating patches for dual-band operation. The ground size of the antenna matches the ground size of a typical hand-held cellular phone for improved compatibility with mobile phone printed circuit boards. The antenna is designed using a simulator and fabricated with optimized parameters. The fabricated antenna is measured at the lower and higher operating frequencies, and the return loss coefficient, gain, and radiation patterns are determined.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6888-6894
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• 2015

Bluetooth 4.0 is the most appropriate technology for Internet of Things, which can be used to enhance and expand the existing areas and areas with a variety of applications. In this paper, an example of the services of the Internet of Things, we developed a tour guide system using the Bluetooth 4.0 and WiFi sensor technology. iBeacon-based push service have been limited to iOS smart phone series, non-iOS family and lower version of iOS 6 smart phones can not receive push-based services. This paper proposed in iBeacon and WiFi sensor is more than tourists, while maintaining the existing system (non-iOS smartphone users) can provide the service to you. Service tourist information as well as that can provide the advertising associated with the service. With 10 kinds of smart phones used in Korea was the experiment on the MAC information collected. This experiment is to track the behaviour of tourists in history can provide customized services can be based. Tourist destinations as well as amusement parks, resorts, etc. If you want to apply this system in a crowded place for user behavior information-gathering feature views over the a prevention of a missing child features such as notifications, risk, prevention is possible for a variety of applications.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.248-251
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• 2010

Smart Phones from a PC using the Internet using a multimedia data service provides a scalable and user convenience is provided in the form of an application. Wired and wireless communications, especially with the reduction of royalty free WiFi or the Internet to download the application program on the PC you're using on the Smart Phone. In this paper, the location API in Android-based Smart Phone, using GPS coordinates identified in the latitude and longitude coordinates can be transferred to the server, Android Smart Phone to know the possibility of retracing the location. You are smart trace back information from the user application program design, development, and real-time GPS location signals combined backtrack to read the GPS location in Google Earth application is to study the trace back.