• The Journal of the Korea Contents Association
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• v.8 no.8
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• pp.47-56
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• 2008

MC(Mission Computer) performs important function in avionics system which tactic data processing, image processing and managing navigation system etc. In general, the fault of SPOF(Single Point Of Failure) in unity system can lead to failure of whole system. It can cause a failure of a mission and also can threaten to the life of the pilot. So, in this paper, we design the HA(Hight-availability) system so that dealing with the failure. And we use HA software like Heartbeat, Fake, DRBD and Bonding to manage HA system. Also we analyze the performance of HA system using the FDT(Fault Detection Time) for fast fault detection and MTTR(Mean Time To Repair) for mission continuity.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10a
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• pp.247-250
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• 2001

멀티미디어 서버 시스템은 고용량이어야 하며 지속적으로 늘어나는 사용자수 뿐만 아니라 추가되는 새로운 저장 공간에 대한 우수한 확장성을 제공하여야 하는 것이 필수 불가결이다. 그러나 현재의 범용 서버 시스템은 이러한 요구사항을 충분히 반영하지 못할 뿐만 아니라 늘어나는 사용자 부하와 시스템 요구에 대한 고려, 그리고 미디어 데이터에 대한 반영이 이루어지지 못하여 점차 증가되는 사용자의 고화질 미디어 서비스 요구 사항을 충족시키지 못하고 있다. 본 논문에서는 구현된 시스템의 서비스 방식과 확장성 있는 구조가 고 대역폭 고화질 On-Demand 서버로서 효율적인 대안임을 보이며 또한 QoS 요구 보장과 효율적인 시스템 Management 정책을 제시하여 범용 서버를 멀티미디어 저장 및 Streaming 서버에 적합한 환경의 클러스터로 구성하는 방법을 제시한다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06a
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• pp.430-432
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• 2006

최근 인터넷 서비스 공급 및 사용자의 폭발적인 증가로 클러스터 파일 시스템에 대한 관심이 높아졌다. 이에 많은 클러스터 파일 시스템이 개발되었지만, 데이터의 가용성 측면에서 문제가 있었다. 이 가용성 문제를 해결하기 위한 방안으로 패리티 서버를 사용하는 방법과. 전체 파일 시스템을 복제하는 방법이 소개되었다. 그러나 이러한 방법들도 가용성을 완벽하게 지원하지 못하였으며 추가적인 비용 또한 발생하였다. 본 논문에서는 파일 시스템에 대한 접근 패턴을 고려한 클러스터 파일 시스템, HA-PVFS를 제안한다. HA-PVFS는 파일 시스템에 존재하는 모든 파일이 아닌, 자주 사용되는 파일만을 접근 패턴을 분석하여 부분 복제함으로써 데이터의 가용성을 지원한다. 따라서 HA-PVFS를 통해 기존의 방법보다 낮은 비용으로 높은 가용성을 보장해 줄 수 있다.

• KCID journal
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• v.18 no.1
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• pp.18-24
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• 2011

The suitable area of forage crop field was calculated under the assumption that all of the liquied manure would be used to nutrient of crops at the Saemangeum crop-livestock complex. At first, Korean cattle and dairy cattle were selected and swine was excluded becausr of high pollution availability. When forage crop was calculated from nutrient amounts of manure of livestocks and standard applicable fertilizer quantity to the selected forage crops, 232ha (278ha including infrastructure part) was determined to be appropriate in case of 2500 heads of Korean cattle and 300 heads of dairy cattle were raised. From the result by that calculated ares (232ha) to forage crop feeding could be possible to the Korean cattle and dairy cattle feeding using TDN index, more than 217ha of forage crop fields would be satisfied nutritionally.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.664-666
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• 2004

최근 업무에 컴퓨터를 이용하는 사례가 늘어나고, 각종 컨텐츠 서비스업계가 발전하면서 독립적인 파일 서버 기능만을 처리하도록 만든 네트워크 저장장치인 NAS(Network Attached Storage)의 이용이 점차 증가하는 추세에 있다. NAS는 기존 파일서버의 문제점을 보완하면서 이기종 플랫폼간의 파일 공유, 스토리지 확장성, 관리 용이성 등을 특징으로 한다. 그러나 NAS 시스템에 장애가 발생할 경우에는 막대한 경제적인 손실이 발생하게 된다. 따라서 본 논문에서는 NAS 시스템 장애가 발생하였을 때, 효율적으로 장애를 복구할 수 있는 HA(High Availability) NAS 시스템을 설계 및 구현하고, 다양한 장애 상황에서 NAS를 이용하는 서비스가 중단 없이 제공되는 것을 확인하였다

• Journal of Forest and Environmental Science
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• v.34 no.1
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• pp.12-23
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• 2018

Quantitative information on biomass and available nutrients are essential for developing sustainable forest management strategies to regulate atmospheric carbon. An attempt was made at Chilapatta Reserve Forest in Duars region of West Bengal to quantify its above and below ground carbon along with available "N", "P" and "K" in the soil. Stratified random nested quadrats were marked for soil, biomass and litter sampling. Indirect or non-destructive procedures were employed for biomass estimation. The amount of these available nutrients and organic carbon quantified in soil indicates that the forest soil is high in organic carbon and available "K" and medium in phosphorus and nitrogen. The biomass, soil carbon and total carbon (soil C＋C in plant biomass) in the forest was 1,995.98, 75.83 and $973.65Mg\;ha^{-1}$. More than 90% of the carbon accumulated in the forest was contributed by the trees. The annual litter production of the forest was $5.37Mg\;ha^{-1}$. Carbon accumulation is intricately linked with site quality factors. The estimated biomass of $1,995.98Mg{\cdot}ha^{-1}$ clearly indicates this. The site quality factor i.e. tropical moist deciduous with optimum availability of soil nutrients, heavy precipitation, high mean monthly relative humidity and optimum temperature range supported luxuriant growth which was realized as higher biomass accumulation and hence higher carbon accumulated.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2711-2713
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• 2001

네트워크는 서버를 유지 운영하기 위한 부수적 요소가 아니라 서버의 한 부분으로서 그 중요성을 더해가고 있으며, 네트워크 자체의 안정성이 서버 전체의 고가용성(HA)을 보장하기 위한 중요한 전제가 되었다. 따라서 네트워크의 속도 및 성능을 향상시키고 고가용성을 보장하기 위한 방법으로, 국지적 네트워크 이중화 방법을 제안한다. 현재의 기술 수준에서의 네트워크 이중화 시도는, 같은 네트워크 안에서 이종 OS와 HW를 갖는 서버들로 구성되는 경우 시스템 구현이 용이하지 않으며, 서버의 기종 또는 해당 플랫폼이 변경될 때마다 보완작업을 하거나 완전히 새로 설계해야 하는 어려움이 있다. 이를 해결하기 위해 본 논문에서는 서버, 혹은 OS의 종류에 독립적인 관점으로 LAN 이중화를 구현하여, 기존의 다중 서버와 함께 네트워크에서의 완전한 HA를 보장할 수 있는 저렴하고 안정적인 H/W 및 관련 S/W 솔루션 개발에 대해 제안하고자 한다.

• The KSFM Journal of Fluid Machinery
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• v.11 no.1
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• pp.26-32
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• 2008

The safe operation of high pressure pipe line systems is of significant importance. Leaks due to faulty operation from the pipelines can lead to considerable product losses and to exposure of community to dangerous gases. There are several leak detection methods of pipeline network which have recently been suggested. The negative pressure wave detection technology, which has advantages of short time detection availability, accurate leaking location estimate capability and cost effective, is concentrated in this study. Theoretical analysis of the flow characteristics for leaking through a hole on the pipe wall has been performed by using Fluent 6.3, commercial CFD package. The results of 3-dimensional analysis near leaking hole confirm the occurrence of negative pressure wave, and the results of 2-dimensional analysis verify the characteristics of propagation of the wave which travels with speed equal to the speed of sound in the pipeline contents. Characteristics of leakage and pressure in a pipe with a hole have been analyzed for the various pipe and hole sizes.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.6
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• pp.81-87
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• 2017

The total area of domestic reclaimed lands is 54,379 ha, and among these, 30,394 ha can be agriculturally available. To increase an agricultural availability of reclaimed land, controlled horticultural products that can be highly profitable have come to the fore. However, as being characteristically concerning, when original glasshouse is intactly applied in reclaimed land, it is unsafe on account of ground subsidence and, even if ground were reinforced, it has a problem by high cost. So a new greenhouse model would be necessary taking into account not only cost-efficiency but also safety with relatively light-weight one. Before this, this paper estimated acceptance rate of controlled horticultural complexes in reclaimed land and new greenhouse model for 414 farmers. The annual rental fee is 129,712,500 won/ha, considering the interest rate (2.5 %) of the investment, the depreciation cost of the facilities (straight line depreciation method, 20 years of service life estimated), and government subsidy rate (50 %) which resulted in a sufficient number of intended tenants with the acceptance rate of 0.33. The results of this paper may contribute to the government's policies for reclaimed land.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.5
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• pp.586-596
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• 1998

The relevance and importance of buffalo production under coconut plantations in the North Westen Province of Sri Lanka was studied in three districts (Bingiriya, Pannala, Kuliyapitiya). The objective of the study was to collect baseline information on socioeconomic and cultural aspects of buffalo production, with a view to promote and disseminate new technologies. The survey technique used consisted of a formal survey using a structured questionnaire (71 households) and rapid appraisal (55 households). The results indicate the existence of a wide stratification of dariy farmers which ranged from skilled dairy operators with high levels of production and management of efficiency to marginal subsistence farmers with low levels of productivity. The most frequent family size of households ranged from 4-5 members (58%), and the average family size was 4.7. The actual average land ownership accounts to 2.4 ha of upland and 0.5 ha of lowland, but when their accessibility to common property resources are taken into account, the land availability was assessed at 13 ha and 0.7 ha of upland and lowland, respectively. The highest average monthly income (Rs. 13,590) was received by farmers with off-farm employment (primary) who are also engaged in livestock production (secondary), and livestock contributed 43% of the total income. Livestock farmers who practised integrated crop farming as a secondary source of income received a monthly income of Rs. 10,843, and those involved in crop production as the primary source received the lowest average income (Rs. 7,295). The survey revealed a high investment cost on concentrate feeds (47%) for milk production. However some farmers obtained higher milk yields (11 litres/cow/day) at lower ration costs, and this could be attributed to the entrepreneurship skills and management efficiency. The study area had a well developed market infrastructure for fresh milk, principally due to the existence of the Nestle's company and the Coconut Triangle Milk Union. On an average the producer collected Rs. 10 per litre of milk marketed.