• Journal of Internet Computing and Services
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• v.3 no.5
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• pp.95-106
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• 2002

In current storage system environment, we use disk mirroring or Chained-declustering scheme to improve data availability and reliability. If disk error is occurred when these schemes are used. we need efficient recovery schemes for these situations. In this paper, it is proposed that a recovery method of disk mirroring that guarantees I/O performance similar to normal state during disk failure, Also, we execute performance evaluation for our recovery scheme and existing schemes in various environments. We show through the simulation that our algorithm outperforms the classic schemes in terms of I/O response time.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2628-2630
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• 2004

In this study, a system that has a high speed digital data I/O and distributive structure is developed and the hardware and software of the system are described in detail. PCI master card to PC slot has maximum 63 slaves which are connected by Ethernet cables and can handle 16 I/O points. The system has some features : easy expansion by adding slaves as needed, space and wiring advantage with distributed characteristics, and select from a range of slave devices that fits best for the use.

• ETRI Journal
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• v.20 no.4
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• pp.301-326
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• 1998

In this paper, we have modeled and evaluated a new parallel processing system called Scalable Parallel computer Architecture based on Xbar (SPAX) for commercial applications. SMP systems are widely used as servers for commercial applications; however, they have very limited scalability. SPAX cost-effectively overcomes the SMP limitation by providing both scalability and application portability. To investigate whether the new architecture satisfies the requirements of commercial applications, we have built a system model and a workload model. The results of the simulation study show that the I/O subsystem becomes the major bottleneck. We found that SPAX can still meet the I/O requirement of the OLTP workload as it supports flexible I/O subsystem. We also investigated what will be the next most important bottleneck in SPAX and how to remove it. We found that the newly developed system network called Xcent-Net will not be a bottleneck in the I/O data path. We also show the optimal configuration that is to be considered for system tuning.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.4
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• pp.122-128
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• 2007

This paper represents the Input/Output (I/O) serial communication methods between overground and overhead controllers using a programmable logic controller (PLC). In general, the systems composed by overground and overhead controllers use exclusive serial communication units. This, however, has a demerit such as a high cost as well as some restrictions of the system itself. Thus, this paper suggests methods by I/O cards for data communication between overground and overhead controllers. In this system, there is no special card and it therefore has a lower cost and is more flexible than the exclusive serial communication unit.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.648-649
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• 2007

변전소의 설비 관리/진단 및 보호, 감시, 제어 등의 자동화 시스템인 SAS(Substation Automation System)의 운영에 있어서 가장 중요한 요인은 System의 신뢰성 확보라 할 수 있다. 즉, Real-time Data에 대한 정확하고 빠른 취득능력은 SAS의 평가 잣대가 될 수 있다. 따라서 SAS 운영의 신뢰성을 증대시키기 위해 상위 HMI(Human Machine Interface)와 하위 Device간의 통신 중계 역할을 하는 I/O Server의 Virtual Simulation Environment인 Hyosung 통합 I/O Server Toolkit(Virtual Device 포함)을 개발하였다.

• IEMEK Journal of Embedded Systems and Applications
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• v.14 no.2
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• pp.63-69
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• 2019

Recently, ultra-low latency flash storage devices such as Z-SSD and Optane SSD were introduced with the significant technological improvement in the storage devices which provide much faster response time than today's other NVMe SSDs. With such ultra-low latency, $10{\mu}s$, storage devices the cost of context switch could be an overhead during interrupt-driven I/O completion process. As an interrupt-driven I/O completion process could bring an interrupt handling overhead, polling or hybrid-polling for the I/O completion is known to perform better. In this paper, we analyze tail latency problem in a polling process caused by process scheduling in data center environment where multiple applications run simultaneously under one system and we introduce our adaptive polling selection technique which dynamically selects efficient processing method between two techniques according to the system's conditions.

• Economic and Environmental Geology
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• v.41 no.1
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• pp.1-14
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• 2008

The Bongsang gold-silver deposit consists of quartz veins that fill along the fault Bone within Cretaceous andesitic lapilli tuff. Mineralization is occurred within fault-breccia zones and can be divided into two stages. Stage I which can be subdivided into early and late depositional stages is main ore mineralization and stage II is barren. Stage I began with deposition of wall-rock alteration minerals and base-metal sulfides, and was deposited by later native silver, Ag-bearing tetrahedrite, polybasite and base-metal sulfides such like pyrite, sphalerite, chalcopyrite and galena. Fluid inclusion data indicate that homogenization temperatures and salinities of stage I range from 137 to $336^{\circ}C$ and from 0.0 to 10.6 wt.% NaCl, respectively. It suggests that ore forming fluids were cooled and diluted with the mixing of meteoric water. Also, temperature and sulfur fugacity deduced mineral assemblages of late stage I are $<210^{\circ}C\;and\;<10^{-15.4}$ atm, respectively. Sulfur(3.4%o) isotope composition indicates that ore sulfur was mainly derived from a magmatic source as well as the host rocks. The calculated oxygen{2.9%o, 10.3%o(quartz: 7.9%o, 8.9%o, calcite: 2.9%o, 10.3%o)}, hydrogen(-75%o) and carbon(-7.0%o, -5.9%o) isotope compositions indicate that hydrothermal fluids may be meteoric origin with some degree of mixing of another meteoric water for paragenetic time.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.77-80
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• 2007

In this paper, the method which can protect the situation of possible data corruption when collision has happened during I/O data exchange between device and tasks is presented. Also, an example diagram of mechanism according to this introduced method is shown and the effect and merits and demerits of the method is evaluated.

• Journal of Korea Technology Innovation Society
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• v.22 no.2
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• pp.265-281
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• 2019

With the advent of the Internet-based economy, the dramatic changes in consumption patterns have been witnessed during the last decades. The seminal change has led by Data Technology, the integrated platform of mobile, online, offline and artificial intelligence, which remained unchallenged. In this paper, I use data analysis tool (TexTom) in order to articulate the definitfite notion of data technology from Internet sources. The data source is collected for last three years (November 2015 ~ November 2018) from Google and Naver. And I have derived several key keywords related to 'Data Technology'. As a result, it was found that the key keyword technologies of Big Data, O2O (Offline-to-Online), AI, IoT (Internet of things), and cloud computing are related to Data Technology. The results of this study can be used as useful information that can be referred to when the Data Technology age comes.

• Journal of KIISE
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• v.43 no.5
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• pp.524-530
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• 2016

The desire to access data faster and the growth of next-generation memories such as non-volatile memories, contribute to the development of research on memory file systems. It is recommended that memory mapped file I/O, which has less overhead than read-write I/O, is utilized in a high-performance memory file system. Memory mapped file I/O, however, brings a page table overhead, which becomes one of the big overheads that needs to be resolved in the entire file I/O performance. We find that same overheads occur unnecessarily, because a page table of a file is removed whenever a file is opened after being closed. To remove the duplicated overhead, we propose the mapping cache, a technique that does not delete a page table of a file but saves the page table to be reused when the mapping of the file is released. We demonstrate that mapping cache improves the performance of traditional file I/O by 2.8x and web server performance by 12%.