• 한국컴퓨터정보학회논문지
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• 제21권2호
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• pp.1-7
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• 2016

In this paper, we propose in this paper present a novel locality data allocation policy as COLD(Correlated Locality Data) allocation policy. COLD is defined as a set of data that will be updated together later. By distributing a COLD into a NAND block separately, it can preserve th locality. In addition, by handling multiple COLD simultaneously, it can obtain the parallelism among NAND chips. We perform two experiment to demonstrate the effectiveness of the COLD data allocation policy. First, we implement COLD detector, and then, analyze a well-known workload. And we confirm the amount of COLD found depending on the size of data constituting the COLD. Secondly, we compared the traditional page-level mapping policy and COLD for garbage collection overhead in actual development board Cosmos OpenSSD. Experimental results have shown that COLD data allocation policy is significantly reduces the garbage collection overhead. Also, we confirmed that garbage collection overhead vary depending on the COLD size.

• 정보과학회 논문지
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• 제44권8호
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• pp.767-773
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• 2017

클라우드 데이터베이스와 같은 분산 시스템 환경에서는 균일한 서비스 품질을 보장하기 위해 꼬리 응답시간을 짧게 유지하는 것이 중요하다. 본 논문에서는 카산드라 데이터베이스를 대상으로, 긴 꼬리 응답시간에 해당하는 지연이 메모리 공간 부족으로 인해 발생한다는 것을 보이며, 이러한 지연이 메모리 공간 확보를 위해 버퍼에 저장된 데이터를 저장장치에 완전히 내려쓸 때까지 카산드라가 사용자의 요청을 받지 않기 때문임을 밝힌다. 버퍼에 저장된 데이터를 내려쓰는데 걸리는 시간은 저장장치 성능에 따라 결정되므로 SSD의 가바지 컬렉션으로 인한 성능 저하가 꼬리 응답시간을 더 길게 만들고 있음을 관찰하였다. 우리는 자바가상기계에서의 가비지 컬렉션과 SSD에서의 가비지 컬렉션을 함께 수행하여 SSD의 가비지 컬렉션 비용을 숨기는, SyncGC 기법을 제안한다. 실험 결과, SyncGC 기법을 통해 꼬리 응답시간인 $99.9^{th}$와 $99.9^{th}-percentile$을 각각 31%, 36% 줄일 수 있었다.

• 대한토목학회논문집
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• 제44권2호
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• pp.231-235
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• 2024

강물을 통해 유입되는 해양 부유 쓰레기는 환경에 부정적인 영향을 주며, 인간의 건강에도 직접적인 위협이 된다. 부유 쓰레기의 유출을 막기 위한 차단시설물을 설치하고 있지만 이들 시설의 유지보수, 특히 차집 쓰레기 수거 스케줄링 대한 관심은 미비하다. 현재 유지관리는 현장 작업자의 경험에 기반한 순차적 수거 방식을 사용하고 있을 뿐이며, 이를 위한 체계적인 연구는 미비하다. 이에 AI기술인 YOLOv7기반 차집량 분석 모니터링 기술을 이용한 새로운 피드백 기반 수거 비용 추정 프레임워크를 제안한다. 제안하는 수거 방식은 CCTV 등의 원격 센서로부터 측정된 차집 쓰레기 정보량을 토대로 수거를 진행하며, MCS로 예상 금액을 통계적으로 경제적 비교를 하였다. 결과적으로 신규 수거 전략을 이용한 방식은 기존 수거 전략 대비 약 63 %의 비용적 우위를 보였다.

• 한국입자에어로졸학회지
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• 제15권2호
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• pp.57-65
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• 2019

Recently, there has been much research on the effect of fine dust on human body with increasing interest in the fine dust. Thermal power plant, which is considered as one of the main sources of fine dust, is reported to be responsible for 14% of the total amount of domestic fine dust in the Republic of Korea. Therefore, dust collecting devices in the thermal power plant need to be improved. In this study, the electrostatic precipitator (ESP) was considered to substitute for a mist eliminator used in flue gas desulfurization facility. By considering real situation in the flue gas desulfurization facility, the collection efficiency of the ESP was evaluated by using the sprayed limestone slurry particles. The collection efficiency of the ESP was higher than that of the mist eliminator, showing the possibility of replacing the mist eliminator with the ESP in flue gas desulfurization facility.

• 기술사
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• 제19권1호
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• pp.25-32
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• 1986

The number of visiters to Bukhan Mt. national park, generation quantity of solid waste and collection system were researched to consider a counterplan for the pollution control of the national park and study for developing the effective treatment of solid waste was tried through the proximate analysis of each component containing. Results obtained in this study were summerized as follows; The great part of visitors go on an excursion to the Bukhan Mt. national park during July and August and also, the solid waste was generated nearly a half of the total amount at the same period. The major collection facilities in the national park were waste basket and incineration box. But the incineration box was too large in volume and very far in distance, and its collection period was irregular, so it was cause to the congestion of solid waste and bad smell and dirty. Therefore, to complete collection of solid waste, we must set up the waste basket which able to find within 40～50m from the origination place of solid waste and induce the visitors to throw the solid waste. It was obtained as moisture content: 48.5 wt%, volatile solid: 28.4wt％, fixed solid: 23.1 wt％, lower heating value: 1,320kca1/kg from experimental analysis of solid waste. According to this analysis, the incineration operation is possible, but the generation quantity of solid waste was too small to construct incineration plant for heat recovery. It was found that it is suitable for the aerobic composting by mixing with the night soil which generate in the national park after the recovery of resources such as metals, glasses and plastics.

• International Journal of Advanced Culture Technology
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• 제11권4호
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• pp.202-209
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• 2023

In the 21st century, the dualistic worldview of the Cold War era collapsed and we entered an era of new creation and fusion. The fusion of different designs between East and West, the design activities of traditional clothing from the past, the use of new materials that are continuously being developed, and the mixing of unique items are being conducted in various fields. However, research is being conducted by combining fusion characteristics with hair. In addition, the period is short and the amount of research is small. Therefore, this study analyzed hairstyles of fusion images shown in hair collection using data of Juno Hair collection from 2013 to 2022 as analysis data and examined types of fusion images shown in the work of folk images, mixed images, and future images. Oriented images were divided into three categories and analyzed. In this study, we added Results of such research can be used not only as data for predicting future fashion trends, but also as basic data for exploring new design developments. In future research, it is expected that convergent research will be conducted, such as analyzing fusion images from an integrated perspective.

• Asian Journal of Atmospheric Environment
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• 제8권2호
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• pp.89-95
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• 2014

There have been a lot of efforts to keep permissible emission standards and to reduce the amount of emitted air pollutants. There are several air pollution control equipments, however, wet scrubber is used to remove particulate matters and gaseous pollutants simultaneously, even if it has low collection efficiency in the particle size less than $5.0{\mu}m$. To overcome this problem, we introduced a spray tower scrubber with an electrospray system which a high voltage was indirectly applied. We found that collection efficiency of fine particles in the electrospray system was improved by increasing electrical field strength and the ratio of liquid-gas flow rate (from 41% to 84% for $0.3{\mu}m$ particles). In addition, a number of small droplets generated from an electrospray system led high collection efficiency, resulting from electrostatic attraction between droplets and particles and higher collision frequency. Therefore, we can conclude that the introduction of an electrospray system is quite effective to increase the particle removal efficiency of a spray tower scrubber.

• 한국기계가공학회지
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• 제20권3호
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• pp.47-52
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• 2021

Fine dust generated from vehicle brakes accounts for a significant amount of fine dust from non-exhaust system. Since such brake fine dust contains a large number of heavy metal components that are fatal to the human body, a device capable of collecting them needs to be developed. A mini cyclone, one of the devices that can effectively collect fine dust, has the advantage of relatively simple shape and high collection efficiency. Therefore, in this study, the collection efficiency of the mini-cyclone was numerically analyzed using CFD in order to find out whether such a mini-cyclone is suitable for collecting brake fine dust. As a result, the cut-off diameter was predicted to be about 1.5㎛, which means that the particle trapping load of the filter can be drastically reduced. Therefore, there is a possibility that the mini-cyclone can be used to collect fine dust from disc brakes.

• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3788-3794
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• 2022

The possibility of denuclearization of the Korean Peninsula has been continuously debated, and the initiative participation of the Republic of Korea has necessitated preemptive measures against neighboring countries. In this study, we present a proposal for formulating a site survey plan when the amount of site information provided is insufficient and the accuracy of the information is not guaranteed. Considering a case wherein "a soil sample analysis is used to determine the presence or absence of nuclear activity" in a radiochemical laboratory, which is a typical key facility for denuclearization, the optimal soil sample collection plan is designed based on international guidelines and public information. In the event of denuclearization, a scenario that is not based on the expertise of the sample collector is set, and the data quality objective (DQO) process is applied to ensure reality. Consequently, the primary sample collection points can be derived in consideration of accessibility, and the sample collection scale can be adjusted according to the cost. By applying the DQO process to ensure sample representativeness and reality, reliable and resource-efficient soil sample collection can be achieved in radiochemical laboratories and other denuclearization facilities.

• 한국입자에어로졸학회지
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• 제12권1호
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• pp.11-20
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• 2016

A large amount of wear dust generated during train operation is a major dust source in urban railway tunnels. To check possibility of a louver dust collector for the removal of dust in the railway tunnel, five louver dust collector models were designed and their performance was tested in a wind tunnel. JIS Z 8901 Class 8 dust was used as a test dust. Pressure drop and particle collection efficiency were evaluated with the face velocity ranging from 1 m/s to 4 m/s. At this low velocity range, particle collection efficiency of the louver dust collector was found to be insensitive to air velocity and design parameters. Pressure drop was under 40 Pa, and $PM_{10}$ and $PM_{2.5}$ collection efficiencies were approximately 50% and 30%, respectively.