• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.2
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• pp.425-430
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• 2009

In medical area, lots of information has been digitized and the desire of personnel health became a matter of primary concern. To satisfy this desire it requires the high-speed handhold Healthcare monitering platform for building U-health system. This paper represents that the implementation of s3c6000 platform with s3c6400 CPU using up-to-date ARM11 technology. This parer also represents building of network system with wireless LAN based on 802.11 in order to transmit medical data. Transmitting and monitoring personnel medical data will be possible in any place with wireless LAN network.

• Journal of Information Processing Systems
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• v.8 no.1
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• pp.1-20
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• 2012

The most important criterion for achieving the maximum performance in a wireless mesh network (WMN) is to limit the interference within the network. For this purpose, especially in a multi-radio network, the best option is to use non-overlapping channels among different radios within the same interference range. Previous works that have considered non-overlapping channels in IEEE 802.11a as the basis for performance optimization, have considered the link quality across all channels to be uniform. In this paper, we present a measurement-based study of link quality across all channels in an IEEE 802.11a-based indoor WMN test bed. Our results show that the generalized assumption of uniform performance across all channels does not hold good in practice for an indoor environment and signal quality depends on the geometry around the mesh routers.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.2107-2112
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• 2006

As growing up of elderly population, the interesting on healthcare system in normal life using W is increasing. An integrated u-healthcare service architecture with IEEE 802.11 and IEEE 802.15.4 based sensor network and code divisi(m multiple access(CDMA) public mobile telecommunication networks was designed and developed. Sensor nodes with electrocardiogram(ECG), body core temperature sensors are attached on the patients' body. The healthcare parameters are transferred to web server via CDMA mobile network or through existed LAN network. The existed LAN network is suggested to be used for continuous monitoring of patient's health status in hospital while mobile networks can be used for general purpose at home or outdoor where infra networks unavailable. This system enable healthcare personal to be able to continuously access, review, monitor and transmit the patients information whereever they are, whenever they want. And immediately check their status by using cellular phone and obtain detail information by communication with medical information server through CDMA. By using this developed integrated u-healthcare service architecture, we can monitor patients' health status for 24 hours.

• Information and Communications Magazine
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• v.33 no.10
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• pp.3-9
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• 2016

AP와 단말이 혼재된 무선랜 환경에서 사용자가 실질적으로 성능 향상을 체감할 수 있는 고효율의 무선랜 표준 개발을 목표로 14년 5월 IEEE 802.11 HEW (High Efficiency WLAN) Task Group이 결성되어 본격적인 표준화 논의가 진행되고 있다. 기존의 무선랜 표준들이 최대전송률 향상에만 초점을 맞췄던 것에 비해, 11ax 표준은 고밀도 중첩 무선랜 환경에서 사용자별 실질적 체감 성능 향상을 목표로 하고 있다. 본 고에서는 6세대 무선랜 표준이 될 IEEE 802.11ax HEW 표준의 표준화 동향 및 주요 요소 기술들에 대해 살펴본다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.11
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• pp.77-83
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• 2010

This paper presents the dual resonance PIFA(Planar Inverted F-Antenna) which satisfies the requirements of the 802.11n standard at both 2.4 GHz and 5 GHz frequency bands. Patch for 2.4 GHz and U-Type slot for 5 GHz were used for dual resonance, respectively. In this paper, the characteristics of an antenna were investigated by varying locations of short plate and feed point, the width of the short plate, the thickness and the location of U-Type slot. To investigate the characteristics of the PIFA, HFSS(High Frequency Structure Simulation) for the simulation was used. And the measurement results of a fabricated PIFA were compared with the simulated ones. The measurement and simulation results show that good dual resonance characteristics as the thickness of U-type slot decreases and when the location of U-type slot is far from the feed point.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.87-89
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• 2006

U-물류/유통, U-항만에 핵심적인 기술이 될 Ultra-Wide(UWB)통신을 위한 광대역 안테나를 설계, 개발하였다. 설계된 안테나는 UWB 주파수 대역인 3.1$^{\sim}$11.7GHz 대역에서 안테나 특성을 만족하고, IEEE 802-11a와HIPERLAN/2에 의해 사용이 제한된 5.15${\sim}$5.825GHz 대역에서 주파수 저지 대역을 가지기 위하여 U모양의 얇은 슬롯을 복사 패치 위에 구현 하였다. 제작한 안테나는 5${\sim}$595GHz 대역을 제외하고는 안테나의 특성을 만족한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.931-934
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• 2007

멀티미디어 디스플레이 시장현황과 성장추이를 보면 현재 멀티미디어 디스플레이는 '진화 중'이라는 표현이 적당할 것으로 보인다. 다양한 종류의 시스템을 인식시키기 위한 호환성이 개선됐고 네트워크 기능 까지 추가 되는 등 계속해서 여러 가지 기술이 응집되고 있다. 무선 랜은 랜 케이블이 없어도 되기 때문에 케이블 연결을 최소화해야 하는 멀티미디어 디스플레이에 필요한 요소이다. 본 논문에서는 IEEE 802.11g wireless mini pci를 탑재한 ARM계열 임베디드 장비에서 C/C++를 사용하여 보다 효율적이고 뛰어난 uClinux기반의 멀티미디어 디스플레이 무선 랜 네트워크 사용자 인터페이스의 구현에 대해서 논의 하고자 한다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.9 s.351
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• pp.80-87
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• 2006

In this paper, we analyze the performance of IEEE 802.11b WLAN communication between access point(AP) and mobile equipment(ME) in 2.4 GHz band with noise and interference factors. WLAN communication at in-vehicle environment is assumed as the communication between main vehicle controller and electronic device such as sensor, ECU (Electrical Control Unit) in vehicle on telematics field for implementing wireless vehicle control system. Received interference level from other system's mobile equipment in the same band and automobile noise from each part of vehicle can be the main factors that can cause increasing error rate of control signal. With these (actors, we focus on the Eb/No the BER performance of WLAN for analyzing the characteristic of interference factors by the measured bit error rate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1200-1205
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• 2006

In this paper, it is presented to the designed and implemented care system fur health diagnosis. The designed handhold care system is implemented by embedded Visual C++4.0 and Pocket PC2003 software development kit (SDK) in an 802.11 wireless network, and we were conducted that the research provide sufficiently the usefulness of the U health system for the collection of care management information. The proposed system is consists of care management module for health diagnosis, personal record module, data transport module, image information management module for clinic. Also, fur emergency status, transmission function of clinic information is implemented by wireless LAN protocol and serial communication.

• The Magazine of the IEIE
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• v.35 no.2
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• pp.81-89
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• 2008