• Journal of Ginseng Research
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• v.34 no.1
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• pp.51-58
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• 2010

This study compared the effects of black, white, and red ginseng extracts (WGE, RGE, BGE, 200 mg/kg, p.o.) on learning and memory deficits associated with scopolamine treatment (SCOP, 2 mg/kg, i.p.). Tacrine (THA, 10 mg/kg, p.o.) was used as a positive control. Ginseng significantly reversed SCOP-induced memory impairment in the passiveavoidance test and also reduced escape latency in training trials of the Morris water maze test. The increased acetylcholinesterase (AChE) activity produced by SCOP was significantly inhibited by WGE and RGE (p<0.001). SCOP administration had no effect on choline acetyltransferase (ChAT) activity, but RGE and BGE significantly increased ChAT activity (p<0.05). SCOP administration increased oxidative damage in the brain. Treatment of amnesic mice with ginseng extracts decreased malondialdehyde (MDA) levels and restored superoxide dismutase (SOD) and catalase (CAT) activity to control levels. These results suggest that black ginseng enhances cognitive activity by regulation of cholinergic enzymes and antioxidant systems.

• Journal of Ginseng Research
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• v.29 no.1
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• pp.37-43
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• 2005

We performed in vitro and in vivo studies to know whether the inhibitory effects of ginsenosides on $5-HT_{3A}$ receptor channel acctivity are coupled to anti-nausea and anti-vomiting action. In vitro study, we investigated the effect of compound K (CK) and M4, which are ginsenoside metabolites, on human $5-HT_{3A}$ receptor channel activity expressed in Xenopus oocytes using two-electrode voltage clamp technique. Treatment of CK or M4 themselves had no effect in both oocytes injected with $H_2O\;and\;5-HT_{3A}$ receptor cRNA. In oocytes injected with $5- HT_{3A}$ receptor cRNA, M4 treatment inhibited more potently 5-HT-induced inward peak current $(I_{5-HT})$ than CK with dose-dependent and reversible manner. The half-inhibitory concentrations $(IC_{50})$ of CK and M4 were $36.9\;\pm\;10.1\;and\;7.3\;\pm\;2.2\;{\mu}M$, respectively. The inhibition of $I_{5-HT}$ by M4 was non-competitive and voltage-independent. These results indicate that M4 might regulate $5-HT_{3A}$ receptors. In vivo experiments, injection of cisplatin (7.5 mg/kg, i.v.) induced both nausea and vomiting with 1 h latency. These episodes reached to peak after 2 h and persisted for 4 h. Pre-treatment of GTS (500 mg/kg, p.o.) significantly reduced cisplatin-induced nausea and vomiting by $51\;\pm\;8.4\;and\;48.8\;\pm\;6.4\%$ during 4 h compared to GIS­untreated group, respectively. These results show the possibility that in vitro inhibition of $5-HT_{3A}$ receptor channel activity by ginsenosides might be coupled to in vivo anti-emetic activity.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.10
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• pp.523-532
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• 2003

Video on Demand(VOD) services cause high resource consumption in a video seuer, because multimedia are characterized by continuous playback, a high bandwidth requirement, and long playback duration. Patching has been proposed to save the network I/O bandwidth of a video server. To achieve true VOD, patching uses multicasting to share video streams, thereby providing immediate VOD services to users without any service latency. A communication channel is used to either multicast the entire video as a regular channel or multicast only the leading portion of a video as a Patching channel. This paper Proposes a buffering patching technique that divides regular channels, as used in patching, into sub-regular channels and regular channels to shorten the holding time of the channels. In the proposed technique, the last portion of video data, corresponding to the size of the buffering window, is not transferred by sub-regular channels, but rather downloaded and buffered in the user buffer from the latest regular channel. When simulations were performed to compare the performance of the proposed technique with that of conventional patching, the results indicated that the proposed technique was superior in terms of the defection rate, average service latency, and fairness, although the amount of video data buffered at each user station was higher than that with patching.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.1
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• pp.33-49
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• 2003

Recently, there have been large storage demands for manipulating multimedia data. To solve the tremendous storage demands, one of the major researches is the SAN(Storage Area Network) that provides the local file requests directly from shared-disk storage and also eliminates the server bottlenecks to performance and availability. SAN also improve the network latency and bandwidth through new channel interface like FC(Fibre Channel). But to manipulate the efficient storage network like SAN, traditional local file system and distributed file system are not adaptable and also are lack of researches in terms of a metadata structure for large-scale inode object such as file and directory. In this paper, we describe the architecture and design issues of our shared-disk file system and provide the efficient bitmap for providing the well-formed block allocation in each host, extent-based semi flat structure for storing large-scale file data, and two-phase directory structure of using Extendible Hashing. Also we describe a detailed algorithm for implementing the file system's device driver in Linux Kernel and compare our file system with the general file system like EXT2 and shard disk file system like GFS in terms of file creation, directory creation and I/O rate.

• The KIPS Transactions:PartB
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• v.9B no.6
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• pp.835-844
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• 2002

The number of channels available to a video server is limited since the number of channels a video server can support is determined by its communication bandwidth. Several approaches such as batching, piggybacking and patching have been proposed to reduce I/O demand on the video server by sharing multicast data. Patching has been shown to be efficient in the matter of the cost for VOD systems. Unlike conventional multicast techniques, patching is a dynamic multicast scheme which enables a new request to join an ongoing multicast. In addition, true VOD can be achieved since a new request can be served immediately without having to wait for the next multicast. In this paper. we propose two types of channel reservation patching algorithm : a fixed channel reservation patching and a variable channel reservation patching. To immediately schedule the requests for popular videos, these algorithms reserve the channels of video server for the fixed number of popular videos or for the variable number of popular videos which is determined dynamically according to the load of video server. The performance of the proposed algorithms is evaluated through simulations, and compared with that of simple patching. Our performance measures are average defection rate, average latency, service fairness and the amount of buffered data according to video server loads. Simulation results show that the proposed channel reservation patching algorithms provide better performance compared to simple patching algorithm.

• Journal of KIISE:Databases
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• v.29 no.1
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• pp.44-57
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• 2002

Multiple spatial queries are defined as two or more spatial range queries to be executed at the same time. The primary processing of internet-based map services is to simultaneously execute multiple spatial queries. To improve the throughput of multiple queries, the time of disk I/O in processing spatial queries significantly should be reduced. The declustering scheme of a spatial dataset of the MIMD architecture cannot decrease the disk I/O time because of random seeks for processing multiple queries. This thesis presents query scheduling strategies to ease the problem of inter-query random seeks. Query scheduling is achieved by dynamically re-ordering the priority of the queued spatial queries. The re-ordering of multiple queries is based on the inter-query spatial relationship and the latency of query processing. The performance test shows that the time of multiple query processing with query scheduling can be significantly reduced by easing inter-query random seeks as a consequence of enhanced hit ratio of disk cache.

• Journal of Korea Multimedia Society
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• v.7 no.3
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• pp.357-367
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• 2004

In VOD systems the number of channels available to a video server is limited since the number of channels, the video server can support, is determined by the communication bandwidth of the video server. Multicast techniques such as batching, patching and batch-patching have been proposed to reduce I/O demand on the video server by sharing multicast data. In this paper, we propose a channel reservation batch-patching technique that first applies the batching technique to hot video requests and then applies the patching technique to the batches of the hot video requests. And the proposed technique reserves a part of the channel capacity of the video server for many hot video requests, so that the hot video requests can be served without defection. The performance of the proposed technique is compared with those of Patching and Batch-Patching techniques in terms of average service latency, defection rate, fairness and frame reduction rate by simulations.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.3 s.357
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• pp.43-51
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• 2007

OneNAND flash combines the advantages of NAND and NOR flash, and has become an alternative to the former. But the advanced features of OneNAND flash are not utilized effectively in demand paging systems designed for NAND flash. We propose delayed dual buffering, a demand paging system which fully exploits the random-access I/O interface and dual page buffers of OneNAND flash demand paging system. It effectively reduces the time of page transfer from the OneNAND page buffer to the main memory. On average, it achieves and 28.5% reduction in execution time and 4.4% reduction in paging system energy consumption.

• Journal of Ginseng Research
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• v.31 no.1
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• pp.44-50
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• 2007

Ginseng powerfully tonifies the original Qi. Ginseng used for insomnia, palpitations with anxiety, restlessness from deficient Qi and blood and mental disorientation. In order to investigate whether Ginseng cerebral ischemia-induced neuronal and cognitive impairments, we examined the effect of Ginseng on ischemia-induced cell death in the hippocampus, and on the impaired learning and memory in the Morris water maze and passive avoidance in rats. Ginseng when administered to rat at a dose of 200 mg/kg i.p. water extracts to 0 minutes and 90 minutes after 4-VO, significantly neuroprotective effects by 86.4% in the hippocampus of treated rats. For behavior test, rats were administered Ginseng (200mg/kg p.o.) daily for two weeks, followed by their training to the tasks. Treatment with Ginseng produced a marked improvement in escape latency to find the platform in the Morris water maze. Ginseng reduced the ischemia-induced learning disability in the passive avoidance. Consistent with behavioral data, treatments with Ginseng reduced jschemia-induced cell death in the hippocampal CA1 area. Oxidative stress is a causal factor in the neuropathogenesis of ischemic-reperfusion injury. Oxidative stress was examined in a rat model of global brain ischemia. The effects of Ginseng on lipid peroxidation (inhibition of the production of malondialdehyde, MDA) in different regions of the rat brain were studied. Ferrous sulfate and ascorbic acid (FeAs) were used to induce lipid peroxidation. The antiperoxidative effect showed 48-72% protection from tissue damage as compared with untreated animals. These results showed that Ginseng have a protective effect against ischemia-induced neuronal loss and learning and memory damage.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.3
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• pp.7-12
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• 2016

DRAM is commonly used as a smartphone memory medium, but extending its capacity is challenging due to DRAM's large battery consumption and density limit. Meanwhile, smartphone applications such as social network services need increasingly large memory, resulting in long latency due to additional storage accesses. To alleviate this situation, we adopt emerging nonvolatile memory (NVRAM) as smartphone's buffer cache and propose an efficient management scheme. The proposed scheme stores all dirty data in NVRAM, thereby reducing the number of storage accesses. Moreover, it separately exploits read and write histories of data accesses, leading to more efficient management of volatile and nonvolatile buffer caches, respectively. Trace-driven simulations show that the proposed scheme improves I/O performances significantly.