• Title/Summary/Keyword: AP

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Implementation of a Stand-Alone Access Point for Wireless LAN in Linux (리눅스로 구현한 무선 LAN 용 통합 Access Point)

  • 박정규;이호빈;송하윤;노삼혁
    • Proceedings of the Korean Information Science Society Conference
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    • 2001.10c
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    • pp.808-810
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    • 2001
  • 현재 무선 네트웍이 발달됨에 따라 Access Point (AP)의 역할이 증대되고 있다. 그러나 현재 사용되고 있는 대부분의 AP는 단순한 HUB의 역할만 하고 있다. 본 연구에서는 기존의 AP에 라우터 기능 및 Mobile IP, Agent 기능을 추가하여 통합 AP를 제시하고 있다. 통합 AP는 AP 내에 필요한 기능이 내장된 것으로서 리눅스 운영체제를 기반으로 하였다. 요구되는 기능을 리눅스 커널에 내장함으로서 AF에 쉽게 포함시킬 수 있다. 또한 무료로 제공되는 리눅스 운영체제를 사용함으로서 기존의 AP에 비해서 저렴하게 통한 AP론 구성할 수 있다.

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Porting linux for IEEE 802.11b WLAN AP (IEEE 802.11b WLAN AP를 위한 리눅스의 이식)

  • 박현문;장영민;정옥조
    • Proceedings of the IEEK Conference
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    • 2003.11c
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    • pp.187-190
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    • 2003
  • 최근 IEEE에서 WLAN을 표준으로 하는 802.11g가 확정되면서 이를 지원하는 AP가 출시되었다. AP에서 사용되는 OS는 POSIX를 기반으로 된 Linux 같은 OS를 통하여 구현되고 있 다. 이 논문에서는 가장 범용으로 사용되고 있는 Rad Hat을 기반으로 한 embeded linux를 만들어본다. 이와 함께 embeded linux를 가지고서 Network 기능을 추가하고, AP 하드웨어 드라이버 및 AP 모듈을 올려서 구연한다. 여기에 추가적으로 DHCP나 Web UI기능 등의 부가 기능을 추가하여 AP를 구현하는데 목적이 있다.

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Physicochemical Properties and Biological Activities of Collagens with Different Molecular Weights from Alaska Pollack (Theragra chalcogramma) Skin (명태 껍질 유래 콜라겐의 분자량에 따른 이화학적 특성 및 생리활성)

  • Yang, Su-Jin;Hong, Joo-Heon
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.43 no.10
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    • pp.1535-1542
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    • 2014
  • This study was conducted to investigate the physicochemical properties and biological activities of collagens with different molecular weights from Alaska pollack (Theragra chalcogramma) skin as well as their efficacies as functional materials. The molecular weights of collagens were between 1~10 kDa (below 1 kDa (AP1), 1~3 kDa (AP2), 3~10 kDa (AP3), and above 10 kDa (AP4). The protein content of AP4 (40.19 g/100 g) was the highest. Collagen contents of AP1, AP2, AP3, and AP4 were 36.43, 32.23, 19.23, and 14.89%, respectively. The free amino acid and essential amino acid contents of AP1 were higher than those of AP2, AP3, and AP4. Fourier transform infrared spectroscopy spectra of collagens with different molecular weights showed wavenumbers representing the regions of amide I, amide II, amide III, and amide A, respectively. The electron-donating ability (29.51%) and SOD-like activity (38.45%) of AP1 were higher than those of AP2, AP3, and AP4. Tyrosinase inhibition activity of AP1 improved with higher treatment concentration. The rate of inhibition of MMP-1 production in HS68 cells exposed to UVB was suppressed by treatment with AP1 (29.78%) and AP2 (26.49%) at 1 mg/mL. Furthermore, there was a strong correlation between DPPH, superoxide dismutase, tyrosinase activity, and MMP-1 inhibition rate of collagens with different molecular weights.

Effects of Fucoidan on Nitric Oxide Production and Activator Protein-1 Activation in Lipopolysaccharide-Stimulated Porcine Peripheral Blood Mononuclear Cells (LPS로 자극한 돼지 말초혈액 단핵구세포의 Nitric Oxide (NO) 생산 및 Activator Protein-1 (AP-1) 활성화에 있어 Fucoidan의 효과)

  • Park, Jongchan;Ahn, Changhwan;Kang, Byeong-Teck;Kang, Ji-Houn;Jeung, Eui-Bae;Yang, Mhan-Pyo
    • Journal of Veterinary Clinics
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    • v.32 no.4
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    • pp.289-294
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    • 2015
  • Fucoidan which is sulfated polysaccharide extracted from brown seaweed has a wide variety of internal biological activities. The objectives of this study were to examine the effect of fucoidan on nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated porcine peripheral blood mononuclear cells (PBMCs) and to investigate whether this effect is involved in the expression of inducible nitric oxide synthase (iNOS) and the activation of activator portein-1 (AP-1). The levels of NO production and AP-1 activity in the culture supernatants from porcine PBMCs were measured by the enzyme-linked immunosorbent assay and the levels of iNOS and AP-1 mRNA were determined by real time polymerase chain reaction. Fucoidan in LPS-naïve PBMCs has no effects on the production of NO and activity of AP-1. Expressions of iNOS and AP-1 mRNA in LPS-naïve PBMCs were also not affected by treatment of fucoidan. However, NO production, AP-1 activity and expressions of iNOS and AP-1 mRNA were dramatically increased in PBMCs stimulated with LPS. Enhancing effects of NO production and AP-1 activity in PBMCs induced by LPS were reduced by addition of fucoidan. Fucoidan also inhibited an increase in expressions of iNOS and AP-1 mRNA in LPS-stimulated PBMCs. These results suggested that fucoidan exerts anti-inflammatory effect by down-regulating production of NO via suppressing expression of iNOS and activity of AP-1 in LPS-stimulated porcine PBMCs.

A Novel Access Point Selection Policy for Load Balancing in IEEE 802.11 WLANs (IEEE 802.11 WLANs 환경에서 핫스팟의 혼잡을 분산하는 AP 선택정책)

  • Lee, Kwang-Gyo;Choi, Chang-Yeol
    • Journal of Industrial Technology
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    • v.28 no.A
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    • pp.105-111
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    • 2008
  • A typical AP (Access Point) selection policy is to select an AP based on the received signal strength indicator (RSSI), ignoring its load. If multiple stations are deployed densely at a particular area, a typical AP selection policy will bring about the overall network throughput degradation. This paper proposes a novel AP selection policy taking into consideration not only signal strength of the APs but also AP loads to avoid Hotspot congestion. An experiment on Alinker implementing proposed AP selection policy, demonstrates that the proposed policy achieves close to optimal load balancing and grants the maximum transmission rate to stations in comparison with SSF (Strongest-Signal-First) and LLF (Least-Loaded-First).

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Research for Adaptive Wireless AP Profile selection via Efficient network connection of Android System-based (안드로이드 시스템 기반의 적응적 무선 AP 프로파일 선택을 통한 효율적 네트워크 연결에 관한 연구)

  • Back, Jong-Kyung;Han, Kyung-Sik;Sonh, Seung-Il
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2012.10a
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    • pp.632-634
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    • 2012
  • In order for the connection to the wireless network from the list of priorities of the wireless AP to AP profile automatic connection by selecting the preferred method to register a profile, which is determined at the time of the change, the user does not respond to the demands of the part. In this study, the frequency of the user's access in accordance with the wireless AP, and by creating a profile, the user needs to meet with regard to network access adaptive research.

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On the Performance Evaluation of the Backoff Selection of AP in an IEEE 802.11 WLAN (IEEE 802.11 WLAN에서 AP의 백오프 값에 따른 TCP성능 변화 연구)

  • Park, Sang-Ha;Woo, Hee-Kyoung;Kim, Chong-Kwon
    • Proceedings of the Korea Information Processing Society Conference
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    • 2005.11a
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    • pp.1371-1374
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    • 2005
  • 지금까지 IEEE 802.11 WLAN 에서 많이 연구되어진 주제는 노드들 간의 공평성(fairness)과 처리량(throughput)을 높이는데 중점이 맞추어진 것들이 대부분이었다. 성능을 높이기 위한 AP의 CW값에 관한 연구는 노드들 간에 관한 연구에 비하여 비교적 적은 편이다. 지금은 노드들과 AP가 충돌하게 되면 BEB(Binary Exponential backoff)방식으로 셋팅되어 사용하게 있기 때문에 1:N의 불공평한(unfairness) 상황이 발생한다. AP에서 노드들로 가는 하향링크(downlink) 전송이 많은 상황에서 AP가 다른 노드들과 똑같은 채널 접근확률을 가지는 것은 바람직하지 않기 때문에 AP에게 우선권(priority)을 주어 전체 성능을 높이는 것이 필요하다. 따라서 본 논문에서는 AP의 CW(Contention Window)값이 변화함에 따라 전체 성능에 끼치는 영향과 노드 수의 변화에 따른 AP의 적절한 백오프 CW값을 분석해 보고자 한다.

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The Effects of Artemisia Princeps var. Orientalis Extracts on Serum Lipids and Connective Tissues Collagen in Ovariectomized Rats (쑥이 갱년기 장애 유도 흰쥐의 혈중 지질 및 결합조직 중 Collagen 함량에 미치는 영향)

  • Kim, Mi-Hyang
    • Korean Journal of Pharmacognosy
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    • v.37 no.4 s.147
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    • pp.324-330
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    • 2006
  • The aim of this study was to evaluate the effects of Artemisia Princeps Var. Orientalis (AP) on serum lipids and the collagen content of the connective tissues in ovariectomized rats. From day 2 until day 37 after the ovariectomy, Sprague-Dawley female rats were randomly assigned to the following groups: sham-operated rats (Sham), ovariectomized control rats (OVX-control), and ovariectomized rats supplemented with the AP 50 mg/kg bw/day (OVX-AP). The AP ethanol extracts were orally administrated 1 mL per day. The OVX rats were significantly heavier than the sham-operated rats at all time points, but supplementation with the AP extracts tended to gain weight less than OVX-control. Although total-cholesterol was increased at OVX-control, supplementation with the AP extracts tended to result in less than OVX-control. Triglyceride was significantly decreased after supplemented with the AP extracts (p<0.05). HDL-cholesterol is appeared higher AP extracts group than OVX-control. According to the results, we could know the fact that AP extracts were effective on serum lipids content throughout decreasing total-cholesterol, triglyceride and increasing HDL-cholesterol in ovariectomized rats. Supplementation with the AP extracts prevented a decrease in the collagen level in bone and cartilage tissues. These results are consistent with the conclusions based on the estrogenic activities of AP. Therefore, it may be used to possibly improve the quality of life in menopausal women.

Intonational Pattern Frequency of Seoul Korean and Its Implication to Word Segmentation

  • Kim, Sa-Hyang
    • Speech Sciences
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    • v.15 no.2
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    • pp.21-30
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    • 2008
  • The current study investigated distributional properties of the Korean Accentual Phrase and their implication to word segmentation. The properties examined were the frequency of various AP tonal patterns, the types of tonal patterns that are imposed upon content words, and the average number and temporal location of content words within the AP. A total of 414 sentences from the Read speech corpus and the Radio corpus were used for the data analysis. The results showed that the 84% of the APs contained one content word, and that almost 90% of the content words are located in AP-initial position. When the AP-initial onset was not an aspirated or tense consonant, the most common AP patterns were LH, LHH, and LHLH (78%), and 88% of the multisyllabic content words start with a rising tone in AP-initial position. When the AP-initial onset was an aspirated or tense consonant, the most common AP patterns were HH, HHLH, and HHL (72%), and 74% of the multisyllabic content words start with a level H tone in AP-initial position. The data further showed that 84.1% of APs end with the final H tone. The findings provide valuable information about the prosodic pattern and structure of Korean APs, and account for the results of a previous study which showed that Korean listeners are sensitive to AP-initial rising and AP-final high tones (Kim, 2007). This is in line with other cross-linguistic research which has revealed the correlation between prosodic probability and speech processing strategy.

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