• Title/Summary/Keyword: Access point

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International Trends and Policy Recommendations Related to Non-Indigenous Species (외래종관리에 관한 국제동향 및 정책방향)

  • Park, Yong-Ha
    • Journal of Environmental Policy
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    • v.1 no.1
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    • pp.25-45
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    • 2002
  • Opening of trade relationships through an increasing number of international free trade agreements and the now defunct General Agreement on Tariffs and Trade has resulted in an increase the number of the species being exchanged in the world. In the last 20 years, international environmental laws have multiplied and a number of treaties address harmful non-indigenous species (NIS) directly with specific provisions, while other treaties deal with related environmental issues and indirectly affect international regulation of NIS; however, such treaties are weak due to lack of enforceability. From the stand point of national law, many countries including the USA, Australia and New Zealand enforce national laws and regulations to protect biological resources. Typical strategies include : 1) strengthening quarantines to prevent unintentional and illegal introduction of harmful NIS, and 2) developing technologies for managing harmful NIS. However, the recent international trend for managing NIS has shifted. In 2002, the Bonn Guidelines on Access to Genetic Resources and Fair and Equitable Sharing of the Benefit Arising out of their Utilization was adopted at the 6th Conference of the Parties to the Convention on Biodiversity. One major issue highlighted in the document is that "there is no more free of charge to get a biological resource from other countries". The Bonn guidelines will affect international and national NIS regulatory systems because the NIS is a potentially disrupts ecosystems as well as native species. A number of impacts are expected including the revamping of national biodiversity policy regimes in many countries in the world. In particular, the ROK, which is not very biologically diverse, has to evolve national laws to protect valuable ecosystems from NIS. In the meanwhile, national rights of using beneficial indigenous and non-indigenous species as biological resources should be considered through the investigation and national registration of NIS around the world for the promotion of the biotech industry.

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A High Efficiency Reconfigurable Doherty Amplifier (고효율의 재구성된 도허티 증폭기)

  • Kim, Ell-Kou;Kim, Young;Yoon, Young-Chul
    • Journal of Advanced Navigation Technology
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    • v.12 no.3
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    • pp.220-226
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    • 2008
  • This paper proposes the Reconfigurable Doherty Amplifier(RDA) with asymmetric structure which has ${\lambda}/4$ impedance transformer for modulating the load impedance in peaking amplifier path. This structure is possible to implement a compact size for N-stage multi Doherty amplifier and to get almost same characteristics that is compared to conventional Doherty amplifier. To realize the high efficiency amplifier, we were implemented 45 Watts power amplifier at transmitter band of Wideband Code Division Multiple Access(WCDMA) base-station. As a result, in case of WCDMA 1 Frequency Allocation(FA) input signals, this amplifier has obtained a 26.3% Power Added Efficiency(PAE) at 8 dB back-off point from P1dB and an Adjacent Channel Leakage Power(ACLR) is -40.4 dBc at center frequency ${\pm}5MHz$ deviation.

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Design of Circular Microstrip Patch 2×2 Array Antenna for S-band Applications (S-밴드용 원형 마이크로스트립 패치 2×2 배열 안테나의 설계)

  • Ahn, Yong-Bok;Choi, Byoung-Ha
    • Journal of Advanced Navigation Technology
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    • v.11 no.1
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    • pp.64-71
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    • 2007
  • In this paper, we have designed and fabricated microstrip antenna of S-band for the wireless LAN and the ISM. It array $2{\times}2$ circular patch antenna elements at plane instead of conventional rectangular patch antenna elements. It optimized to size calculated of single patch antenna. The radiation elements distance is array $0.24{\lambda}$. The fabricated circular patch antenna decreased 8% of size compared to the conventional rectangular patch antenna. In the E-plane, designed circular microstrip patch $2{\times}2$ array antenna gain is 12.7[dBi], half power beam width is $40^{\circ}$ and in the H-plane, antenna gain is 12.1[dBi], half power beam width is $45^{\circ}$. Bandwidth is 250[MHz] (VSWR < 2).

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A Study on the Operating Status and Development Direction of Public Library in Busan Metropolitan City (부산시 공공도서관의 운영현황 및 발전방향에 관한 연구)

  • Park, Jae-Yong
    • Journal of Korean Library and Information Science Society
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    • v.43 no.4
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    • pp.69-88
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    • 2012
  • This research is to find a direction of development through operating status survey of public library in Busan metropolitan city. First, Normally library users visit the library to check out books or to have a private study session. Also users normally obtained information about upcoming events done in the library through using offline search methods. Second, although the usage of the website was low, however the users demanded the increase in computer numbers in the library and online database for home access. Third, the users acknowledged the importance of the public library to their local community. Library policy indicator rated high in importance to the local community(m=3.86). However the reference desk(m=2.87), checkout desk(m=2.41), computer availability(m=2.47), as well as up-to-date artifact availability(m=2.64) did not reach the average point of 3.0. Thus, revealing that the public library's management policies were not sufficient enough to satisfy the needs of the library users.

Design Planning of Group-Home for the elderly in Rural Area (농촌형 고령자 그룹홈의 사례와 제안)

  • Nam, Yun-Cheol
    • Journal of the Korean Institute of Rural Architecture
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    • v.17 no.4
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    • pp.75-82
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    • 2015
  • The elderly rate in South Korea in 2015 is over 13.1%. Especially, the elderly rate in rural area is high. Senior community project in rural that is being promoted by the government. This study's purpose is to provide the reserch group-home for the elderly in Japan rural area. And this paper provided planning of group-home for the elderly in Korea rural area. For this study, respective 5senior housing of Korea and Japan were chosen as respresenting two nations, and every manager was interviewed on housing pattern. This study suggests the planning material as following. First, the effectiveness of the group-home are big. Especially, the elderly was far healthier. Design point is public space(living room, small living room, etc). Maybe, healthy group-home concept is that would be design by Korean traditional housing. Also important public space design is that would be inner courtyard-house, wood floor, Deachong, etc. Two group-homes will construct elderly welfare facilities in between. Otherwise that is need layout of a big public space. In the case of vacant house can used by considering of scale, structure, site condition. Closed school can used through so easy remodeling too. More often than not complex type(hospital, community heath center) was appeared in Japan rural area. In the case of Korea, recommend complex type in community health center and public building. In this case, considering communication, access, contact, group-home keeps on ground floor. In this paper, we hope to take a lesson from group-home planning source for the elderly in Korea rural area.

Optimized implementation of HIGHT algorithm for sensor network (센서네트워크에 적용가능한 HIGHT 알고리즘의 최적화 구현 기법)

  • Seo, Hwa-Jeong;Kim, Ho-Won
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.15 no.7
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    • pp.1510-1516
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    • 2011
  • As emergence of the ubiquitous society, it is possible to access the network for services needed to us in anytime and anywhere. The phenomena has been accelerated by revitalization of the sensor network offering the sensing information and data. Currently, sensor network contributes the convenience for various services such as environment monitoring, health care and home automation. However, sensor network has a weak point compared to traditional network, which is easily exposed to attacker. For this reason, messages communicated over the sensor network, are encrypted with symmetric key and transmitted. A number of symmetric cryptography algorithms have been researched. Among of them HIGHT algorithm in hardware and software implementation are more efficient than tradition AES in terms of speed and chip size. Therefore, it is suitable to resource constrained devices including RFID tag, Sensor node and Smart card. In the paper, we present the optimized software implementation on the ultra-light symmetric cryptography algorithm, HIGHT.

Enhancing IEEE 802.11 Power Saving Mechanism (PSM) with a Time Slotted Scheme (시분할 방법에 의한 IEEE 802.11 전력관리 메커니즘의 성능향상)

  • Lei, Xiaoying;Rhee, Seung Hyong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38B no.8
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    • pp.679-686
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    • 2013
  • Power efficiency becomes more important in wireless LANs as the mobile stations send more data with limited batteries. It has been known that the IEEE 802.11 PSM is not efficient in high load networks: AP cannot deliver buffered packets to a PS station immediately and it can lead the station to stay in active state quite long and result in energy waste. Moreover, it is inefficient that only one data frame is retrieved by a PS-POLL frame. In this paper, we propose a time slotted scheme to enhance the PSM, in which a mobile station can reserve time slots to receive data frames. Our mechanism can reduce collisions by reservation and decrease the channel occupancy by transmitting multiple data frames via one PS-POLL. The analytic model and simulation results show that proposed scheme reduces power consumption significantly and enhances the performance of PSM.

An Efficient AP Selection Strategy in Wi-Fi based Vechicle-to-Infrastructure Communications (Wi-Fi 기반의 차량과 기지국간 통신에서 효과적인 AP 선택에 관한 연구)

  • Hwang, Jae-Ryong;Lee, Hwa-Ryong;Choi, Jae-Hyuk;Yoo, Joon;Kim, Chong-Kwon
    • The KIPS Transactions:PartC
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    • v.17C no.6
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    • pp.491-498
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    • 2010
  • Wi-Fi based vehicle-to-infrastructure (V2I) communication is an emerging solution to improve the safety, traffic efficiency, and comfort of passengers. However, due to the high mobility of vehicles and the limited coverage of Wi-Fi APs, the V2I system may suffer from frequent handoffs although roadside APs can support cost effective Internet connectivity. Such problem of V2I systems can be overcome with Mobile AP (MAP) platform. The MAPs yield longer service duration by moving along with vehicles, yet they provide a lower link capacities than the roadside APs. In this paper, we propose a new association control mechanism that effectively determines whether the vehicle will select a fixed roadside-AP or a nearby MAP in mobile vehicular network environments. We consider both the achievable link bandwidth and available connection duration as a selection criterion and provide their run-time estimation method. Extensive simulation using real traces show significant performance improvements.

A Low Latency Handoff Scheme with Lossless Remote Subscription for Real-time Multimedia Communications in Mobile IP Environments (모바일 IP환경에서의 실시간 멀티미디어 통신을 위한 무손실 원격지 가입 저 지연 핸드오프)

  • Kim Ho-cheal;Kim Young-tak
    • Journal of KIISE:Information Networking
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    • v.31 no.6
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    • pp.620-632
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    • 2004
  • IP is not suitable for mobile nodes by network-based routing because mobile nodes are dynamically change their network attachment point. Mobile-IP is an IETF standard providing continuous access to the Internet for mobile nodes, but it has the triangle routing problem. Also it has a performance degradation problem by massive packet loss during layer 3 handoff of mobile nodes. Especially, two IETF multicast support schemes for Mobile-IP do not guarantee the quality of realtime multimedia services because they have several problems such as long routing path, packet duplication(hi-directional tunneling) and massive packet loss(remote subscription). In this paper, we propose a lossless remote subscription scheme that guarantees the quality of realtime multimedia services over Mobile-IP. From the result of simulation, we verified that the proposed scheme in this paper can reduce the delay time of remote subscription by the effect of the low latency handoff scheme that is extended to apply to the multicast group management and it requires only 0.58% buffer spaces of the previously proposed lossless remote subscription scheme.

A Power Saving Routing Scheme in Wireless Networks (무선망에서 소비 전력을 절약하는 라우팅 기법)

  • 최종무;김재훈;고영배
    • Journal of KIISE:Information Networking
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    • v.30 no.2
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    • pp.179-188
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    • 2003
  • Advances in wireless networking technology has engendered a new paradigm of computing, called mobile computing, in which users carrying portable devices have access to a shared infrastructure independent of their physical locations. Wireless communication has some restraints such as disconnection, low bandwidth, a variation of available bandwidth, network heterogeneity, security risk, small storage, and low power. Power adaptation routing scheme overcome the shortage of power by adjusting the output power, was proposed. Existing power saving routing algorithm has some minor effect such as seceding from shortest path to minimize the power consumption, and number of nodes that Participate in routing than optimal because it select a next node with considering only consuming power. This paper supplements the weak point in the existing power saving routing algorithm as considering the gradual approach to final destination and the number of optimal nodes that participate in routing.