• Title/Summary/Keyword: High-capacity

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Capacity Analysis of M-ary PPM UWB System In Optical Fiber over AWGN (AWGN Optical Fiber에서 M-ary PPM UWB 시스템의 채널용량 분석)

  • Im, Joon-Soon;Shin, Myung-Gon;Kim, Tae-Woong;Park, Seung-Kwon
    • Proceedings of the IEEK Conference
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    • 2005.11a
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    • pp.201-204
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    • 2005
  • In this paper, based on an extended model containing correlator and soft decision decoding, the capacity is evaluated in the single-user case when the inputs are equiprobable. With this method, we adjusted optical communication over AWGN. It is found that only when bit- signal-to-noise ratio (bit-SNR) is high enough, larger M leads to higher capacity; and for a specific M, the optimal values of PPM time offset parameter Td, which maximize the capacity, are independent of bit-SNR. In this paper, the capacity of UWB system in optical fiber over AWGN is proven to improve 1.73 times larger than AWGN channel Capacity.

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Analysis of the Capacity Credit of Wind Farms (풍력발전기의 Capacity Credit추정에 관한 연구)

  • Wu, Liang;Park, Jeong-Je;Choi, Jae-Seok
    • Proceedings of the KIEE Conference
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    • 2008.11a
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    • pp.16-18
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    • 2008
  • Because of being environmentally friendly, renewable energy resources has been growing at a high rate. Wind energy is one of the most successfully utilized of such sources for producing electrical energy. Due to the randomness of wind speed, wind farms can not supply power with a balanceable level as well as conventional power plants. The reliability evaluation of wind power is more and more important. Capacity credit is used to estimate the capacity credit of power systems including wind farms. This paper presents a method of capacity credit calculation for a power system considered wind farms and shows how it gets study on an actual power system (the Jeju Island power system). The paper describes the step of capacity credit calculation and presents test results, which indicate its effectiveness.

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An Approach for Bridge Construction Cost Allocation Considering Traffic Load and Traffic Capacity (교통량과 교통하중을 고려한 교량건설비용의 할당)

  • Lee, Dong-Ju;Hwang, In-Keuk
    • IE interfaces
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    • v.17 no.2
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    • pp.142-148
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    • 2004
  • The objective of bridge construction cost allocation is to distribute in a fair and rational manner the bridge construction costs among those vehicles using the bridge. In most bridge construction cost allocation studies, bridge construction costs are mainly distributed according to traffic load(gross vehicle weight), without any consideration of bridge capacity requirements(the number of lanes). In this paper, a bridge cost allocation method for considering both traffic capacity and traffic loads is developed. The proposed method is based on cooperative game theory, particularly two concepts known as the Aumann-Shapley (A-S) value and Shapley value. This method can help to analyze the impact of traffic capacity costs. By applying the proposed method to an example, traffic capacity cost is found to be high so that traffic capacity should be considered to allocate the bridge construction costs to vehicle classes in a more equitable manner.

Antioxidant capacity of crude extract and fractions from Woodfordia fruticosa flower

  • Bhatt, Lok Ranjan;Baek, Seung-Hwa
    • Advances in Traditional Medicine
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    • v.7 no.2
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    • pp.162-170
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    • 2007
  • Woodfordia fruticosa Kurz. (Lythraceae), commonly known as Dhayero, is used in the treatment of various ailments in Nepal. In this study, the antioxidant capacity of crude extract and different polarity fractions of Woodfordia fruticosa flowers were assayed for their scavenging abilities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and nitric oxide radicals, competitive ${\beta}$-carotene bleaching, reducing power, metal chelating ability and total phenolic content. Crude extract and polar fractions showed stronger antioxidant capacity and contained very high level of total phenolics. They exhibited strong DPPH radical scavenging, nitric oxide scavenging and reducing power, medium ${\beta}$-carotene bleaching and poor metal chelating capacity. Positive correlation obtained between total phenolic content and antioxidant capacity assays, indicated the contribution of phenolics toards antioxidant capacity.

Preliminary in vitro evaluation of some traditional Ayurvedic antacids

  • Nahar, Nusratun;Choudhuri, M Shahabuddin Kabir;Alamgir, Mahiuddin
    • Advances in Traditional Medicine
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    • v.7 no.4
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    • pp.441-443
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    • 2007
  • A preliminary in vitro acid neutralizing capacity test of twelve traditional Ayurvedic antacids were performed in this study. Five traditional preparations of ash of conch shell, ash of oyster, ash of pearl, limestone, and ash of cowrie showed high acid neutralizing capacity similar to standard antacid combination of $Al(OH)_3\;and\;Mg(OH)_2$. Among these the ash of conch shell found the highest acid neutralizing capacity. The ash of tamarind and ash of Achyranthus aspera showed moderate acid neutralizing capacity. The acid neutralizing capacity of red ochre; ash of iron; mixture of niter, alum and ammonium chloride; saltpeter; and ash of mica found below the USP 23 limit.

Erlang Capacity and Call Blocking Probability of CDMA Hierarchical Cellular Systems with Soft Handoff (소프트 핸드오프를 갖는 CDMA 계층구조 셀룰러 시스템의 Erlang 용량과 호 차단확률)

  • Seong, Bong-Hun;O, Hyeon-Seok;Han, Jae-Chung
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.49 no.8
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    • pp.481-490
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    • 2000
  • This paper analyzes interference power, Erlang capacity, the number of handoff occurrences, and call blocking probability with respect to the cell radius, the soft handoff region, and the mobile's velocity in a CDMA hierarchical cellular system. The microcell cellular system has the higher Erlang capacity than the macrocell cellular system. However, the microcell cellular system, which has a high system capacity through frequency reuse has the call blocking probability higher than macrocell cellular system. Also the interference power and the call blocking probability are decreased with the operation of soft handoff. Therefore, this paper presents the optimization of soft handoff region so as to maximize system's Erlang capacity with the low the call blocking probability according to mobile's velocity in the CDMA hierarchial cellular system.

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Effects of Different Heat Treatments on Damping Capacity of Cu-55%Mn Alloy (Cu-55%Mn 합금의 진동감쇠능에 미치는 각종 열처리의 영향)

  • Chung, Tae-Shin;Jun, Joong-Hwan;Lee, Young-Kook;Choi, Chong-Sool
    • Journal of the Korean Society for Heat Treatment
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    • v.11 no.1
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    • pp.27-34
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    • 1998
  • Effects of different heat treatments on microstructure and damping capacity of Cu-55%Mn alloy were investigated to find an optimum heat treatment condition for a maximum damping capacity. The alloy showed the high level of damping capacity in case of the aging at 375 and $400^{\circ}C$. This is ascribed to the FCC${\rightarrow}$FCT martensitic transformation and microstructural changes from mottled to tweed band type. The damping capacity had a maximum value of 0.33 in logarithmic decrement when the alloy was aged at $375^{\circ}C$ for 14 hours followed by 20 times of thermal cycling between room temperature and $250^{\circ}C$. The refinement of tweed structure by thermal cycling is thought to be responsible for the highest damping capacity.

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On the development of Intelligent Railway Logistics Terminal (수송력 향상을 위한 지능형 철도물류터미널 구축방안)

  • Kim, Dong-Hee
    • Journal of the Korea Safety Management & Science
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    • v.12 no.4
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    • pp.175-181
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    • 2010
  • The government have plans to improve the railway transport capacity and transport hub for the sustainable national transport and logistics system. Specially, there are much efforts to improve transportation capacity such as high speed transportation of rail freight, enlargement of BT train, development of double stack train, etc. between railway transport hubs. If the transport capacity between railway logistics hubs is increased as planned, we must increase the handling capacity of railway hub terminals. But there are limits to enlarge the terminal infrastructure because of investment scale, location circumstances and urban development plans. To ensure the capacity, with the minimum required enlargement of infrastructure, it is necessary to extremely increase the efficiency of terminal operations. For improving the efficiency, we have to introduce the efficient terminal operation systems based on u-IT and operation optimize technologies. In this paper, we analyse the issues and problems of railway terminals(including ICD) and suggest the concept of intelligent railway terminal and the construction components of technology.

Achievable Ergodic Capacity of a MIMO System with a MMSE Receiver

  • Kim, Jae Hong;Kim, Nam Shik;Song, Bong Seop
    • Journal of electromagnetic engineering and science
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    • v.14 no.4
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    • pp.349-352
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    • 2014
  • This paper considers the multiple-input multiple-output (MIMO) system with linear minimum mean square error (MMSE) detection under ideal fast fading. For $N_t$ transmit and $N_r({\geq}N_t)$ receive antennas, we derive the achievable ergodic capacity of MMSE detection exactly. When MMSE detection is considered in a receiver, we introduce a different approach that gives the approximation of a MIMO channel capacity at high signal-to-noise ratio (SNR). The difference between the channel capacity and the achievable capacity of MMSE detection converges to some constant that depends only on the number of antennas. We validate the analytical results by comparing them with Monte Carlo simulated results.

Health Capacity to Work at Older Ages in South Korea: Estimates and Implications for Public Pension Policies

  • KIM, DOHYUNG
    • KDI Journal of Economic Policy
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    • v.41 no.2
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    • pp.41-58
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    • 2019
  • Health capacity to work for the elderly is an essential piece of information for designing social policies in an aging society. Here, we assess the health capacity to work of older men in South Korea and provide a cross-country comparison. Following the methodology proposed by Milligan and Wise (2012), which uses the cohort mortality rate as a proxy for overall health status, we quantify the additional employment capacity of current older men in reference to the mortality-employment relationship of a generation ago. Despite the high employment rate of older men in South Korea, we find substantial additional employment capacity among older men (those aged 55 or more) as of 2016 comparable in size to those found in other advanced countries. We also find evidence that older men are not merely capable of working but are also willing to work, and many of them are increasingly combining pension income and work. These findings suggest that labor supply disincentives for older men embedded in public pension systems in South Korea need to be thoroughly reexamined and adjusted accordingly lest they should inhibit the labor supply of older workers.