• Title/Summary/Keyword: I/O latency

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Effects of white ginseng and red ginseng extract on learning performance and acetylcholinesterase activity inhibition (백삼과 홍삼추출물의 학습수행과 Acetylcholinesterase 억제에 미치는 효과)

  • Lee, Mi-Ra;Sun, Bai-Shen;Gu, Li-Juan;Wang, Chun-Yan;Mo, Eun-Kyoung;Yang, Sun-Ah;Ly, Sun-Young;Sung, Chang-Keun
    • Journal of Ginseng Research
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    • v.32 no.4
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    • pp.341-346
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    • 2008
  • In the present study, we assessed the effects of white ginseng and red ginseng extract on the learning and memory impairments induced by scopolamine. The cognition-enhancing effect of ginseng extracts was investigated using the Morris water maze and Y-maze test. Drug-induced amnesia was induced by treating animals with scopolamine (2 mg/kg, i.p.), an antagonist of muscarinic acetylcholine (ACh) receptor. Tacrine was used a positive control. Ginseng extract (200 mg/kg, p.o.), tacrine (10 mg/kg, p.o.) administration significantly reduced the escape latency during training in the Morris water maze (p<0.05). At the probe trial session, scopolamine significantly increased the escape latency on day 5 in comparison with control (p<0.01). The effect of ginseng extracts on spontaneous alternation in Y-maze was similar to that of scopolamine treated group. In addition, numbers of arm entries were similar in all experimental groups. Moreover, red ginseng extract significantly inhibited acetylcholinesterase activity in the cortex and serum (p<0.05). Brain ACh contents of ginseng extract treated groups increased more than that of scopolamine group, which did not show statistically significant. These results suggest that ginseng extract may be useful for the treatment of cognitive impairment.

A Request Scheduling Strategy using Client's Buffer in VOD Systmes (주문형 비디오 시스템에서 클라이언트 버퍼를 활용한 요구 스케쥴링 기법)

  • Han, Kum-Hee;Kim, Jong-Hoon;Won, Yoo-Hun
    • The Transactions of the Korea Information Processing Society
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    • v.7 no.2
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    • pp.337-346
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    • 2000
  • In a Vod(video0on-demand) system, a scheduling strategy is designed to increase the system efficiency and to eatisfy the isochronous requirements of showing a video to multiple viewers with one disk access. In this paper, we have proposed the Stream Relay Scheme (SRS) which utilizes the client's buffer space to reduce the server's disk I/O, buffer consumption, and stream capacity. Under the SRS which we have proposed in this paper, the server does not service all the requests directly but forwards the new request selectively to the client who is being served currently in order to reduce the initial latency and increase the system throughput. The SRS-BAT which integrated the SRS with the Batching technique is introduced. The results of the simulated experiments which compared the SRS with the conventional technique have shown the noticeable performance improvements in terms of initial latency and the server throughput.

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Efficient Incorporation of Tertiary Storage in a Multimedia DBMS (멀티미디어 DBMS에서 3차 저장장치의 효율적 활용 기법)

  • Mun, Chan-Ho;Gang, Hyeon-Cheol
    • The Transactions of the Korea Information Processing Society
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    • v.6 no.7
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    • pp.1724-1737
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    • 1999
  • Multimedia data service applications have to store and manipulate LOBs(unstructured large objects) composing multimedia data. As such, the tertiary storage devices such as an optical disk jukebox and a tape library that consist of a number of platters (the disks in case of an optical disk jukebox and the cartridge tapes in case of a tape library) have been considered essential for the storage system of a DBMS in order to efficiently support storage and management of vary large volume of data. Since the latency with tertiary storage is too long, the schemes for efficient retrieval of LOBs out of tertiary storage need to be investigated. In this paper, we investigated the tertiary I/O Considering the performance characteristics of the LOBs, we proposed various I/O scheduling heuristic algorithms that reduce latency in query processing with LOB retrieval from tertiary storage, and evaluated their performance through a detailed simulation.

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Design and Implementation of Hybrid Hard Disk I/O System based on n-Block Prefetching for Low Power Consumption and High I/O Performance (저전력과 입출력 성능이 향상된 n-블록 선반입 기반의 하이브리드 하드디스크 입출력 시스템 설계 및 구현)

  • Yang, Jun-Sik;Go, Young-Wook;Lee, Chan-Gun;Kim, Deok-Hwan
    • Journal of KIISE:Computer Systems and Theory
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    • v.36 no.6
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    • pp.451-462
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    • 2009
  • Recently, there are many active studies to enhance low I/O performance of hard disk device. The studies on the hardware make good progress whereas those of the system software to enhance I/O performance may not support the hardware performance due to its poor progress. In this paper, we propose a new method of prefetching n-blocks into the flash memory. The proposed method consists of three steps: (1)analyzing the pattern of read requests in block units; (2)determining the number of blocks prefetched to flash memory; (3)replacing blocks according to block replacement policy. The proposed method can reduce the latency time of hard disk and optimize the power consumption of the computer system. Experimental results show that the proposed dynamic n-block method provides better average response time than that of the existing AMP(Adaptive multi stream prefetching) method by 9.05% and reduces the average power consumption than that of the existing AMP method by 11.11%.

Performance Evaluation of SSD-Index Maintenance Schemes in IR Applications

  • Jin, Du-Seok;Jung, Hoe-Kyung
    • Journal of information and communication convergence engineering
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    • v.8 no.4
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    • pp.377-382
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    • 2010
  • With the advent of flash memory based new storage device (SSD), there is considerable interest within the computer industry in using flash memory based storage devices for many different types of application. The dynamic index structure of large text collections has been a primary issue in the Information Retrieval Applications among them. Previous studies have proven the three approaches to be effective: In- Place, merge-based index structure and a combination of both. The above-mentioned strategies have been researched with the traditional storage device (HDD) which has a constraint on how keep the contiguity of dynamic data. However, in case of the new storage device, we don' have any constraint contiguity problems due to its low access latency time. But, although the new storage device has superiority such as low access latency and improved I/O throughput speeds, it is still not well suited for traditional dynamic index structures because of the poor random write throughput in practical systems. Therefore, using the experimental performance evaluation of various index maintenance schemes on the new storage device, we propose an efficient index structure for new storage device that improves significantly the index maintenance speed without degradation of query performance.

RESEARCH OF COMMUNICATION SCHEDULING BETWEEN COMPUTER I/O AND S/W FOR ACQUISITION OF SATELLITE SENSORED DATA

  • Koo, Cheol-Hea;Park, Su-Hyun;Kang, Soo-Yeon;Yang, Koon-Ho;Choi, Sung-Bong
    • Proceedings of the KSRS Conference
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    • v.1
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    • pp.196-199
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    • 2006
  • Various communication mechanisms have been developed to acquire a meaningful data from sensors. The key requirement during the sensor data acquisition is determinism and reduction of time dependency. It is a fundermental level of satellite data management for controlling satellite operation software data acquisition from sensors or subsystem. Satellite operation software has various software modules to be operated in addition to data acquisition. Therefore, unnecessary time delay shall be minimized to perform the data acquisition. As the result, interrupt method might be prefered than polling method because the former can decrease the restriction of design during implementation of data acquisition logic. The possible problems while using interrupt method like as interrupt latency caused by delaying of interrupt processing time are analyzed. In this paper, communication mechanism which can be used to interface with satellite computer and subsidary subsystem by using interrupt is presented. As well, time dependency between software scheduling and data acquisition is analyzed.

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Analysis of I/O Response Time Throughout NVMe Driver Implementation Architectures (NVMe 드라이버 구현 방식에 따른 I/O 응답시간 분석)

  • Kang, Ingu;Joo, Yongsoo;Lim, Sung-Soo
    • IEMEK Journal of Embedded Systems and Applications
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    • v.12 no.3
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    • pp.139-147
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    • 2017
  • In recent years, non-volatile memory express (NVMe), a new host controller interface standard, has been adapted to overcome performance bottlenecks caused by the acceleration of solid state drives (SSD). Recently, performance breakthrough cases over AHCI based SATA SSDs by adapting NVMe based PCI Express (PCIe) SSD to servers and PCs have been reported. Furthermore, replacing legacy eMMC-flash storage with NVMe based storage is also considered for next generation of mobile devices such as smartphones. The Linux kernel includes drivers for NVMe support, and as the kernel version increases, the implementation of the NVMe driver code has changed. However, mobile devices are often equipped with older versions of Android operating systems (OSes), where the newest features of NVMe drivers are not available. Therefore, different features of different NVMe driver implementations are not well evaluated on Android OSes. In this paper, we analyze the response time of the NVMe driver for various Linux kernel version.

Ethanol Extract of Perillae Herba Enhances Pentobarbital-Induced Sleep and Non-Rapid Eye Movement (NREM) Sleep through GABAA-ergic Systems

  • Kwon, Yeong Ok;Ha, Tae-Woo;Oh, Ki-Wan
    • Natural Product Sciences
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    • v.23 no.1
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    • pp.53-60
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    • 2017
  • Perillae Herba has been traditionally used for the sedation in the oriental countries. Therefore, this study was conducted to determine whether Perillae Herba ethanol extract (PHEE) enhances pentobarbital-induced sleeping behaviors in animals. In addition, the possible mechanisms are demonstrated. PHEE (12.5, 25 and 50 mg/kg. p.o.) reduced the locomotor activity in mice. PHEE reduced sleep latency and augmented the total sleep time in pentobarbital (42 mg/kg, i.p.)-induced sleep in mice. Furthermore, the number of sleeping mice treated with sub-hypnotic pentobarbital (28 mg/kg, i.p.) increased. PHEE (50 mg/kg. p.o.) decreased the sleep/wake cycles and wakefulness, and increased total sleeping time and NREM sleep in electroencephalogram (EEG) of rats. In addition, PHEE (0.1, 1.0 and $10{\mu}g/ml$) increased the intracellular $Cl^-$ level through the GABA receptors in the hypothalamus of rats. Moreover, the protein of glutamate decarboxylase (GAD) was overexpressed by PFEE. It was found that PHEE enhanced pentobarbital-induced sleeping behaviors through $GABA_A-ergic$ transmissions.

Performance Improvement of MMO Gameservers Using RIO and HTM (RIO와 HTM을 이용한 MMO 게임서버의 성능 개선)

  • Kang, Subin;Jung, NaiHoon
    • Journal of Korea Game Society
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    • v.20 no.6
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    • pp.13-22
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    • 2020
  • RIO is a new network API for Windows that is designed to have high I/O performance through low overhead and latency. Using RIO, MMO game servers may have much performance benefits. In addition, HTM has better productivity and performance compared to existing synchronization methods, so adopting it may produce better performance, also. In this paper, we improved server performance by implementing a new MMO game server architecture optimized with RIO and HTM. The performance of the server was verified through a benchmark program, and the number of concurrent users increased by 19%.

Forsythiaside, a Constituent of the Fruits of Forsythia suspense, Ameliorates Scopolamine-Induced Memory Impairment in Mice

  • Kim, Sun-Ho;Kim, Dong-Hyun;Choi, Ji-Joung;Lee, Jong-Gu;Lee, Choong-Ho;Park, Se-Jin;Jung, Won-Yong;Park, Dong-Hyun;Ko, Kwang-Ho;Lee, Seung-Ho;Ryu, Jong-Hoon
    • Biomolecules & Therapeutics
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    • v.17 no.3
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    • pp.249-255
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    • 2009
  • Forsythiaside is a polyphenolic constituent of the fruits of Forsythia suspense Vahl which are widely used as anti-inflammatory herbal raw materials in traditional Chinese medicine. In the present study, the authors assessed the effects of forsythiaside on learning and memory impairments induced by scopolamine using a passive avoidance and the Morris water maze tests in mice. Drug-induced amnesia was induced by scopolamine treatment (1 mg/kg, i.p.). Forsythiaside (10 mg/kg, p.o) administration significantly prevented scopolamine-induced step-through latency reduction in the passive avoidance test and scopolamine-induced increased escape latency in the Morris water maze test (p<0.05). Moreover, in an ex-vivo study, forsythiaside treatment (10 mg/kg, p.o) significantly reduced the increase of thiobarbituric acid reactive substance levels induced by scopolamine (p<0.05). Taken together, the present study suggests that forsythiaside could be useful for the treatment of cognitive impairment, and that its beneficial effects are mediated, in part, by its antioxidative properties.