• Title/Summary/Keyword: Fast Storage

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The Optimal Scheduling and Operational characteristics on Battery Energy Storage System (전지전력저장설비의 최적운용 및 운전특성에 관한 연구)

  • Song, Kil-Yeong;Oh, Kwang-Hae;Kim, Yong-Ha;Rho, Dae-Seok
    • Proceedings of the KIEE Conference
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    • 1993.07a
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    • pp.102-105
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    • 1993
  • The objective of this study is to solve the operation scheduling problem of plural battery energy storage systems (BESS), and to find useful intonation from its result. Unlike conventional energy storage system, BESS has on hardware characteristics such as high efficiency, fast-acting response and operational loss. Considering rate constraints of thermal unit power as well as hardware characteristics of BESS, the operation scheduling has an intricated problem. In order to solve this optimization problem, we use successive approximations dynamic programming. In two types of operation, the proposed algorithm is applied to test system. one is daily optimal operation, the other weekly optimal operation.

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Shape Sensitivity Analysis for the Optimal Design of Air Bearing Sliders of Optical Disk Drives (광디스크 드라이브 공기베어링 슬라이더의 최적설계를 위한 형상민감도 해석)

  • Kim, Hyun-Ki;Jang, Hyuk;Kim, Kwang-Sun;Lim, Kyong-Hwa;Jeong, Tae-Gun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.11a
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    • pp.742-747
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    • 2000
  • The optical storage device has recently experienced significant improvements, especially for the aspects of high capacity and fast transfer rate. However, it is the fact that the optical storage device has the lower access time for the randomly scattered data compared to the hard disk drives. It is, therefore, necessary to develop a new type of optical storage system. In this study, we investigate the air bearing characteristics for the optical disk drives which have the swing arm actuator similarly to the hard disk drives. Considering the requirements of the optical disk drives, we parametrize the shape of the air bearing surface and investigate its sensitivity to the flying characteristics for further optimized design outputs.

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Lessons Learned from Energy Storage System Demonstrations for Primary Frequency Control

  • Yu, Kwang-myung;Choi, In-kyu;Woo, Joo-hee
    • KEPCO Journal on Electric Power and Energy
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    • v.4 no.2
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    • pp.107-114
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    • 2018
  • In recent years, ESS (Energy Storage System) has been widely used in various parts of a power system. Especially, due to its fast response time and high ramp rate, ESS is known to play an important role in regulating grid frequency and providing rotational inertia. As the number of installed and commercially operating ESSs increases, the reliability becomes an important issue. This paper introduces control schemes and presents its test method for grid-connected ESS for primary frequency regulation. The test method allows to verify the control operation in the individual operation mode and state. A validation of the method through actual ESS test in a electrical substation is presented in the case study section.

Recent Progress in Dielectric-Based Ultrafast Charging/Discharging Devices (유전체를 활용한 초고속 에너지 충/방전 소자 기술)

  • Choi, Hyunsu;Ryu, Jungho;Yoon, Woon-Ha;Hwang, Geon-Tae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.35 no.4
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    • pp.322-332
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    • 2022
  • Energy storage capacitors based on dielectric ceramics with superior polarization properties and dielectric constant can provide much higher output power density due to their very fast energy charging/discharging rates, which are particularly suitable for operating pulsed-power devices. For an outstanding energy storage performance of dielectric capacitor, a large recoverable energy density could be derived by introducing a slim polarization-electric field hysteresis loop into dielectric materials by various technical approaches. Many research teams have explored various dielectric capacitor technologies to demonstrate high output power density and ultrafast charging/discharging behavior. This article reviews the recent research progress in high-performance dielectric capacitors for pulsed-power electronic applications.

A Data Centric Storage based on Adaptive Local Trajectory for Sensor Networks (센서네트워크를 위한 적응적 지역 트라젝토리 기반의 데이터 저장소 기법)

  • Lim, Hwa-Jung;Lee, Joa-Hyoung;Yang, Dong-Il;Tscha, Yeong-Hwan;Lee, Heon-Guil
    • The KIPS Transactions:PartC
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    • v.15C no.1
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    • pp.19-30
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    • 2008
  • Sensor nodes are used as a storage space in the data centric storage method for sensor networks. Sensor nodes save the data to the node which is computed by hash table and users also access to the node to get the data by using hash table. One of the problems which the data centric storage method has is that queries from many users who are interested in the popular data could be concentrated to one node. In this case, responses for queries could be delayed and the energy of heavy loaded node could be dissipated fast. This would lead to reduction of network life time. In this paper, ALT, Data Centric Storage based on Adaptive Local Trajectory, is proposed as scalable data centric storage method for sensor network. ALT constructs trajectory around the storage node. The scope of trajectory is increased or decreased based on the query frequency. ALT distributes the query processing loads to several nodes so that delay of response is reduced and energy dissipation is also distributed.

Carbon Storage of Exotic Slash Pine Plantations in Subtropical China

  • Jin, Ling;Liu, Yuanqiu;Ning, Jinkui;Liu, Liangying;Li, Xiaodong
    • Journal of Forest and Environmental Science
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    • v.35 no.3
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    • pp.150-158
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    • 2019
  • Exotic conifer trees have been extensively planted in southern China because of their high apparent growth and yield. These fast-growing plantations are expected to persist as a considerable potential for temporary and long-term carbon sink to offset greenhouse gas emissions. However, information on the carbon storage across different age ranges in exotic pine plantations is often lacking. We first estimated the ecosystem carbon storage across different age ranges of exotic pine plantations in China by quantifying above- and below-ground ecosystem carbon pools. The carbon storage of each tree component of exotic pine (Pinus elliottii) increased significantly with increasing age in Duchang and Yiyang areas. The stem carbon storage except <10 years in Ji'an areas was the largest component among all other components, which accounts for about 50% of the total carbon storage followed by roots (~28%), branches (~18%), and foliage (~9%). The mean total tree carbon storage of slash pine plantations for <10, 10-20 and 20-30 years across three study areas was 3.69, 13.91 and $20.57Mg\;ha^{-1}$, respectively. The carbon stocks in understory and forest floor were age-independent. Total tree and soil were two dominant carbon pools in slash pine plantations at all age sequences. The carbon contribution of aboveground ecosystem increased with increasing age, while that of belowground ecosystem declined. The mean total ecosystem carbon storage of slash pine plantations for <10, 10-20 and 20-30 years across China was 30.26, 98.66 and $98.89Mg\;ha^{-1}$, respectively. Although subtropical climate in China was suitable for slash pine growth, the mean total carbon stocks in slash pine plantations at all age sequences from China were lower than that values reported in American slash pine plantations.

A Flash-based B+-Tree using Sibling-Leaf Blocks for Efficient Node Updates and Range Searches

  • Lim, Seong-Chae
    • International Journal of Internet, Broadcasting and Communication
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    • v.8 no.3
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    • pp.12-24
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    • 2016
  • Recently, as the price per bit is decreasing at a fast rate, flash memory is considered to be used as primary storage of large-scale database systems. Although flash memory shows off its high speeds of page reads, however, it has a problem of noticeable performance degradation in the presence of increasing update workloads. When updates are requested for pages with random page IDs, in particular, the shortcoming of flash tends to impair significantly the overall performance of a flash-based database system. Therefore, it is important to have a way to efficiently update the B+-tree, when it is stored in flash storage. This is because most of updates in the B+-tree arise at leaf nodes, whose page IDs are in random. In this light, we propose a new flash B+-tree that stores up-to-date versions of leaf nodes in sibling-leaf blocks (SLBs), while updating them. The use of SLBs improves the update performance of B-trees and provides the mechanism for fast key range searches. To verify the performance advantages of the proposed flash B+-tree, we developed a mathematical performance evaluation model that is suited for assessing B-tree operations. The performance comparisons from it show that the proposed flash B+-tree provides faster range searches and reduces more than 50% of update costs.

Innovation and craft in a climate of technological change and diffusion

  • Hann, Michael A.
    • The Research Journal of the Costume Culture
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    • v.25 no.5
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    • pp.708-717
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    • 2017
  • Industrial innovation in Britain, during the eighteenth and nineteenth centuries, stimulated the introduction of the factory system and the migration of people from rural agricultural communities to urban industrial societies. The factory system brought elevated levels of economic growth to the purveyors of capitalism, but forced people to migrate into cities where working conditions in factories were, in general, harsh and brutal, and living conditions were cramped, overcrowded and unsanitary. Industrial developments, known collectively as the 'Industrial Revolution', were driven initially by the harnessing of water and steam power, and the widespread construction of rail, shipping and road networks. Parallel with these changes, came the development of purchasing 'middle class', consumers. Various technological ripples (or waves of innovative activity) continued (worldwide) up to the early-twenty-first century. Of recent note are innovations in digital technology, with associated developments, for example, in artificial intelligence, robotics, 3-D printing, materials technology, computing, energy storage, nano-technology, data storage, biotechnology, 'smart textiles' and the introduction of what has become known as 'e-commerce'. This paper identifies the more important early technological innovations, their influence on textile manufacture, distribution and consumption, and the changed role of the designer and craftsperson over the course of these technological ripples. The implications of non-ethical production, globalisation and so-called 'fast fashion' and non-sustainability of manufacture are examined, and the potential benefits and opportunities offered by new and developing forms of social media are considered. The message is that hand-crafted products are ethical, sustainable and durable.

Fast-Transient Repetitive Control Strategy for a Three-phase LCL Filter-based Shunt Active Power Filter

  • Zeng, Zheng;Yang, Jia-Qiang;Chen, Shi-Lan;Huang, Jin
    • Journal of Power Electronics
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    • v.14 no.2
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    • pp.392-401
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    • 2014
  • A fast-transient repetitive control strategy for a three-phase shunt active power filter is presented in this study to improve dynamic performance without sacrificing steady-state accuracy. The proposed approach requires one-sixth of the fundamental period required by conventional repetitive control methods as the repetitive control time delay in the synchronous reference frames. Therefore, the proposed method allows the system to achieve a fast dynamic response, and the program occupies minimal storage space. A proportional-integral regulator is also added to the current control loop to eliminate arbitrary-order harmonics and ensure system stability under severe harmonic distortion conditions. The design process of the corrector in the fast-transient repetitive controller is also presented in detail. The LCL filter resonance problem is avoided by the appropriately designed corrector, which increases the margin of system stability and maintains the original compensation current tracking accuracy. Finally, experimental results are presented to verify the feasibility of the proposed strategy.

A Fast Block Mode Decision Scheme for P- Slices of High profile in H.264/AVC

  • Kim, Jong-Ho;Pahk, Un-Kyung;Kim, Mun-Churl;Choi, Jin-Soo
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2009.01a
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    • pp.142-147
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    • 2009
  • The recent H.264/AVC video coding standard provides a higher coding efficiency than previous standards. H.264/AVC achieves a bit rate saving of more than 50 % with many new technologies, but it is computationally complex. Most of fast mode decision algorithms have focused on Baseline profile of H.264/AVC. In this paper, a fast block mode decision scheme for P- slices in High profile is proposed to reduce the computational complexity for H.264/AVC because the High profile is useful for broadcasting and storage applications. To reduce the block mode decision complexity in P- pictures of High profile, we use the SAD value after $16{\times}16$ block motion estimation. This SAD value is used for the classification feature to divide all block modes into some proper candidate block modes. The proposed algorithm shows average speed-up factors of 47.42 ${\sim}$ 67.04% for IPPP sequences.

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