• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2005년도 한국컴퓨터종합학술대회 논문집 Vol.32 No.1 (A)
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• pp.478-480
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• 2005

본 논문에서는 모바일 셀룰러 네트워크상에서 다양한 이동 단말 이동성을 이용한 동적인 Location Update 기법을 제안한다. 동적인 Location Update 기법에서는 다양한 이동 단말들의 이동 패턴을 고려하기 위해서 Differentiated-Walk Model을 이용하고 그 모델에서 제공하는 핸드오프 확률과 이동성 등급을 이용하여 LA(Location Area)를 형성한다. LA는 사용자의 이동 패턴을 고려하여 동적으로 형성되며 본 논문에서는 이러한 LA를 기반으로 제공되는 페이징 기법을 제안한다.

• 제어로봇시스템학회논문지
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• 제18권1호
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• pp.47-53
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• 2012

In cellular geo-location systems, positioning performance is influenced by hearability of receivers. Hearability can be enhanced by using long integration at the receiver. When unknown residual frequency remains in baseband signals, however, the coherent integration loss increases as the residual frequency becomes larger. Consequently, length of coherent integration is determined by the residual frequency. By precise estimation and compensation of the residual frequency, integration length can be enlarged. This paper presents a residual frequency estimator for WiBro geo-location and analyzes its performance in multipath environment. By computer simulation, an optimal receiver structure to enhance the hearability of WiBro geo-location is proposed.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2000년도 봄 학술발표논문집 Vol.27 No.1 (A)
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• pp.223-225
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• 2000

Mobile ad hoc network는 무선으로 연결된 호스트들이 쉽게 이동할 수 있는 망으로써, 미리 설치된 유선망을 이용하는 Cellular망과 달리 이동 호스트사이의 통신만으로 이루어진 망이다. 이 Mobile Ad Hoc Network에서는 각각의 노드들의 이동성이 높기 때문에 이 각각의 노드들의 라우팅 경로를 결정하는 것이 중요하다. 이에 따라 Ad Hoc Network를 위한 많은 라우팅 프로토콜이 이미 제안되었다. 본 논문은 Location 정보를 이용한 Location Aided Routing(LAR)에 고정 호스트(Post)가 존재할 경우 Mobile ad hoc network에서의 향상된 Routing 기법을 제안한다. Location Aided Routing은 일발 flooding 기법에 비하여 Request zone을 이용하여 제한된 영역에서 라우팅을 하기 때문에 성능이 향상되었다. 본 논문에서는 여기에 고정 호스트를 두어 더욱 제한된 영역에서 라우팅을 하기 때문에 기존의 라우팅에 비하여 성능이 향상되었다.

• 한국경영과학회지
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• 제33권3호
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• pp.43-58
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• 2008

In this paper, we have presented a dynamic, predictive location update scheme that takes into account each user's mobility patterns. A user's past movement history is used to create two-dimensional transition probability matrix which makes use of two directional consecutive location areas. A mobile terminal utilizes the transition probability to develop a predictive path which consists of several predictive nodes and then the location update is saved as long as a mobile user follows the predictive path. Using continuous-time Markov chain, cost functions of location update and paging are derived and it is shown that the number of predictive nodes can be determined optimally. To evaluate the proposed scheme, simulations are designed and the numerical analysis is carried out. The numerical analysis features user's mobility patterns and regularity, call arrival rates, and cost ratio of location update to paging. Results show that the proposed scheme gives lower total location management cost, compared to the other location update schemes.

• 한국전자파학회논문지
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• 제15권10호
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• pp.1011-1017
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• 2004

UWB(Ultra Wideband) 기술은 초고속통신, 고정밀의 위치정보시스템 등을 구현하기 위하여 500 MHz 이상의 광대역 주파수 자원이 요구되고 있다. UWB 신호의 에너지는 DC로부터 수 GHz까지 광대역 특성을 갖기 때문에, 현재 사용되고 있는 통신시스템들과의 간섭에 대한 분석이 필수적이라고 할 수 있지만 아직까지 국내에서 UWB 신호와 Cellular CDMA(Code Division Mutiple Access) 이동통신과 WCDMA(Wideband CDMA)와 간섭에 대한 연구가 이루어지고 있지 않다. 본 논문에서는 임펄스 방식과 DS-CDMA(Direct Sequence-CDMA) 방식의 UWB 신호원과 국내 이동통신 서비스중 Cellular CDMA와 WCDMA의 간섭에 관하여 측정을 하고 분석하였다. 본 논문의 결과로부터, 임펄스 방식에 비해 DS-CDMA방식의 UWB 신호는 이동통신시스템에 간섭효과가 크지 않다는 사실을 얻었다.

• Journal of Microbiology and Biotechnology
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• 제19권9호
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• pp.904-910
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• 2009

The development of effective cellular imaging requires a specific labeling method for targeting, tracking, and monitoring cellular/molecular events in the living organism. For this purpose, we studied the cellular uptake of isocyanide-functionalized silver and gold nanoparticles by surface-enhanced Raman scattering (SERS). Inside a single mammalian cell, we could monitor the intracellular behavior of such nanoparticles by measuring the SERS spectra. The NC stretching band appeared clearly at ${\sim}2,100cm^{-1}$ in the well-isolated spectral region from many organic constituents between 300 and 1,700 or 2,800 and $3,600cm^{-1}$. The SERS marker band at ${\sim}2,100cm^{-1}$ could be used to judge the location of the isocyanide-functionalized nanoparticles inside the cell without much spectral interference from other cellular constituents. Our results demonstrate that isocyanide-modified silver or gold nanoparticle-based SERS may have high potential for monitoring and imaging the biological processes at the single cell level.

• 한국통신학회논문지
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• 제21권9호
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• pp.2402-2414
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• 1996

Registration is the process by which a base station gets the information of location and status about mobile stations. Registration will become an increasingly important issue in mobile cellular communications, especially in microcellular system with the increase of location updating traffic. Four typesof registration schemes, which are specified in US standard IS-95 and Korean standard TTA-KO-0062, power up registration scheme, power down registration scheme, distance based registration scheme and zone based registration scheme, will be mainly used in the future. In this paper, we derive the combined cost of signaling traffic of paging and registration for various parameters of mobile stations behavior(unencumbered call duration, power up and down rate, velocity, etc.) then we present numerical results for the perfroamnce of four registration schemes. The size of location area is provided for optimal operation.

• 한국생산제조학회지
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• 제22권6호
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• pp.963-968
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• 2013

In this study, we carried out a structural analysis for determining the stresses acting on the tempered glass of a freely falling cellular phone using ANSYS 13.0, commercial finite element code. We designed a phone heavier than any contemporary cellular phone and performed finite element analysis using the falling speed at a height of 104 cm, which is equal to of the average leg length of Koreans. By determining the maximum stress acting on the phone's tempered glass and frame, we identified the location of large deformation. Furthermore, we evaluated the maximum/minimum equivalent stress and deformation of the reinforced glass and frame as functions of time.

• 한국지반공학회지:지반
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• 제12권5호
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• pp.55-62
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• 1996

Lateral loading model tests were performed on the rigid box-shaped cellular bulkhead by displacement-controlled method. The materials of ground and fill used in this study are two aluminium rods with different sections. The behalf·iotas of ground and fill were recorded by photo/video techniques and failure mechanism created in ground and fill has been simulated two-야mensionally. Also the theoretical consideration about the test results was done on the basis of Hansen's earth pressure theory. As a result, the shape of sliding face the location of sliding face and the loading height was also investigated.

• 인터넷정보학회논문지
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• 제2권5호
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• pp.49-58
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• 2001

Mobile positioning measurement is the most important technology for Location Based Services in the cellular networks. Generally, we are expecting to use GPS to guarantee high accuracy of the mobile position, A CDMA network-based technique for the Mobile Station position calculation needs to be implemented in the cdma2000 network whether the handsets have GPS or not, The most reliable methods of the network-based location technologies are based on the estimation of time of signal traveling between MS and B18 in a network whose coordinates are identified, Other signal parameters such as the power of the received signal and the signal arrival direction cannot be used as main data for a location system because adoption of only the signal parameters will not meet the FCC requirements, In practice, the estimates of the time of signal propagation between MS and BTS always have errors resulting from low-resolution power of measurements and multi path signal propagation, This paper describes the combined network-based location technology in the cdma2000 1× necessary to meet US FCC requirements. The issues of a calibration table and statistic processing based on the pilot strength as well as combined network-based location technologies(TOA/ TDOA) will help to achieve higher location accuracy than specified in the US FCC Rule.