• Journal of Internet of Things and Convergence
• /
• v.9 no.1
• /
• pp.19-24
• /
• 2023

Recently, with the recent rapid development of memory technology, various types of memory are developed and are used to improve processing speed in data management systems. In particular, NAND flash memory is used as a main media for storing data in memory-based storage devices because it has a nonvolatile characteristic that it can maintain data even at the power off state. However, since the recently studied memory-based storage device consists of various types of memory such as MRAM and PRAM as well as NAND flash memory, research on memory management technology is needed to improve data processing performance and efficiency of media in a storage system composed of different types of memories. In this paper, we propose a memory mapping scheme thought technique for efficiently managing data in the storage device composed of various memories for data management. The proposed idea is a method of managing different memories using a single mapping table. This method can unify the address scheme of data and reduce the search cost of data stored in different memories for data tiering.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.11 no.11
• /
• pp.5301-5323
• /
• 2017

Small cell deployment offers a low-cost solution for the boosted traffic demand in heterogeneous cellular networks (HCNs). Besides improved spatial spectrum efficiency and energy efficiency, future HCNs are also featured with the trend of network architecture convergence and feasibility for flexible mobile applications. To achieve these goals, dual connectivity (DC) is playing a more and more important role to support control/user-plane splitting, which enables maintaining fixed control channel connections for reliability. In this paper, we develop a tractable framework for the downlink SINR analysis of DC assisted HCN. Based on stochastic geometry model, the data-control joint coverage probabilities under multi-frequency and single-frequency tiering are derived, which involve quick integrals and admit simple closed-forms in special cases. Monte Carlo simulations confirm the accuracy of the expressions. It is observed that the increase in mobility robustness of DC is at the price of control channel SINR degradation. This degradation severely worsens the joint coverage performance under single-frequency tiering, proving multi-frequency tiering a more feasible networking scheme to utilize the advantage of DC effectively. Moreover, the joint coverage probability can be maximized by adjusting the density ratio of small cell and macro cell eNBs under multi-frequency tiering, though changing cell association bias has little impact on the level of the maximal coverage performance.

• YAKHAK HOEJI
• /
• v.59 no.6
• /
• pp.278-283
• /
• 2015

The computerized prospective Drug Utilization Review (DUR) program supported by the Korean government has provided alerts to physicians and pharmacists since December 2010. This study aims to propose and apply the tiering system in "drug combinations to avoid (DCA)" and "age-precaution" alerts based on severity to improve the compliance of users. To propose the severity and clinical importance of 647 DCA alerts and 140 age precautions, a Delphi evaluation survey was conducted. An expert panel comprising 5 clinical pharmacists and 5 physicians were participated in mail surveys. Based on the results of Delphi survey, DCA pairs were classified into 3 groups; group 1 (70.6%), 2 (26.9%), and 3 (2.8%). Drug-age precaution ingredients were also classified into three groups; group 1 (53.6%), group 2 (40.7%), and group 3 (5.7%). When this grouping was applied to claim data from 2011 to 2013, the majority of alerts had occurred in the groups of high severity. Presenting DUR alerts with severity level is expected to improve the compliance of clinicians. The implementation of tiering system in DUR criteria should be considered.

• Journal of Digital Convergence
• /
• v.10 no.8
• /
• pp.159-172
• /
• 2012

In the recent, due to explosion of Digital Universe, the performance of computer and storage system is reducing. Therefore, the upgrade and capacity expansion needs is growing. Countermeasure for this problem is required fundamental and long-term solutions rather than piecemeal expansion. In this paper, we establish a data management policy for an enterprise through the operational status of storage system and the analysis of data value of it, and implement ILM-based tiered storage system on the basis of these. The results of this study shows the overall throughput was improved about 21% compared to the existing system, it is very effective to maintain continuous quality and reduce operating costs in the long term aspect.

• Journal of KIISE
• /
• v.42 no.6
• /
• pp.691-698
• /
• 2015

Application launch time is an important performance metric to user experience in desktop and laptop environment, which mostly depends on the performance of secondary storage. Application launch times can be reduced by utilizing solid-state drive (SSD) instead of hard disk drive (HDD). However, considering a cost-performance trade-off, utilizing SSDs as caches for slow HDDs is a practicable alternative in reducing the application launch times. We propose a new SSD caching scheme which migrates data blocks from HDDs to SSDs. Our scheme operates entirely in the file system level and does not require an extra layer for mapping SSD-cached data that is essential in most other schemes. In particular, our scheme does not incur mapping overheads that cause significant burdens on the main memory, CPU, and SSD space for mapping table. Experimental results conducted with 8 popular applications demonstrate our scheme yields 56% of performance gain in application launch, when data blocks along with metadata are migrated.