• The Journal of the Korea Contents Association
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• v.20 no.8
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• pp.368-374
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• 2020

Journaling file systems (JFS) manage changes of file systems not yet committed in a data structure known as a journal to restore the file system in the event of an unexpected failure. Extra write operations required for journaling negatively affect the performance of JFS. The high-performance and byte-addressable non-volatile memory (NVM) was expected to easily mitigate these performance problems by providing NVM space as journal storage. However, even with such non-volatile memory technologies, performance problems still arise due to scalability problems inherent in processing transactions of JFS. To solve this problem, we proposes a technique for processing file system transactions for scalable performance. To this end, lock-free data structures are used and multiple I/O requests are allowed to simultaneously be processed on high-performance storage devices with multiple I/O channels. We evaluate the file system with the proposed technique by comparing the original ext4 file system and the recent proposed NVM-based journaling file system on a multi-core server, and experimental results show that our file system has better performance (up-to 2.9/2.3 times) than the original ext4 file system and the recent NVM-based journaling file system, respectively.

• Food Science of Animal Resources
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• v.23 no.3
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• pp.262-268
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• 2003

Kefir is a traditional fermented milk in Caucasusian area and is made mainly of milk fermented with lactic acid bacteria and yeasts. Six typical kefir grains were selected from ten kefir grains collected from different locals in Korea. Kefir grains were gelatinous in texture and had various shapes of villi, grapes, leaves, hulled millets, and towels. To investigate predominant microflora of kefir grains, SPC, MRS, M17, Rogosa, and APT agar media were used for viable cell count MRS, SPC, and Rogosa media were most acceptable for bacterial cell counts of the selected kefir grains. From one or two of the SPC agar plates which contained around 25∼50 colonies, all grown colonies were isolated and identified. Most predominant bacteria was identified as Lactobacillus fermentum by API 50 CHL kit. The proportions of Lb. fermentum and Lb. brevis among the total identified bacteria were around 41~88% and M4%, respectively. To select the best preservation method for kefir grains, refrigeration, freezing, and freeze drying were compared. Freeze drying was found most suitable for the preservation of kefir grains, based upon their acid-producing activities and production of off-flavors.

• Journal of Korean Society of Disaster and Security
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• v.12 no.1
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• pp.11-21
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• 2019

This study assessed the risk of disaster by using QRE(Quick Risk Estimation - UNISDR Roll Model City of Basic Evaluation Tool) tools for three natural disasters and sixteen social disasters managed by the Seoul Metropolitan Government. The criteria for selecting 19 disaster types in Seoul are limited to disasters that occur frequently in the past and cause a lot of damage to people and property if they occur. We also considered disasters that are likely to occur in the future. According to the results of the QRE tools for disaster type in Seoul, the most dangerous type of disaster among the Seoul city disasters was "suicide accident" and "deterioration of air quality". Suicide risk is high and it is not easy to take measures against the economic and psychological problems of suicide. This corresponds to the Risk ratings(Likelihood ranking score & Severity rating) "M6". In contrast, disaster types with low risk during the disaster managed by the city of Seoul were analyzed as flooding, water leakage, and water pollution accidents. In the case of floods, there is a high likelihood of disaster such as localized heavy rains and typhoons. However, the city of Seoul has established a comprehensive plan to reduce floods and water every five years. This aspect is considered to be appropriate for disaster prevention preparedness and relatively low disaster risk was analyzed. This corresponds to the disaster Risk ratings(Likelihood ranking score & Severity rating) "VL1". Finally, the QRE tool provides the city's leaders and disaster managers with a quick reference to the risk of a disaster so that decisions can be made faster. In addition, the risk assessment using the QRE tool has helped many aspects such as systematic evaluation of resilience against the city's safety risks, basic data on future investment plans, and disaster response.

• Journal of the Korean GEO-environmental Society
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• v.16 no.7
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• pp.5-13
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• 2015

The pressure penetrating steel pipe pile method which can be constructed in a narrow space using the hydraulic jack is used on the foundation reinforcement, extension of the structure and basement, restoration of the differential settlement etc.. This method is possible to construct in narrow areas and low story height, the non-noise and non-vibration works, and it is possible for the construction site to be clean without slime. And it is possible to confirm the bearing capacity of pile due to penetrating the pile with the compression load of hydraulic jack. In this study, the static load test with the load-transfer test was carried out to investigate the bearing behavior characteristics of the pressure penetrating steel pipe pile. Four series of static load test were executed to investigate the variation of bearing behavior of the pressure penetrating steel pipe pile. As a result of these tests, the allowable load of the pressure penetrating steel pipe was evaluated more than 637 kN, and the shaft resistance corresponding to 81~86% of each applied load was mobilized with only a small portion of the base resistance acting. And it was also evaluated that the unit skin friction was mobilized to maximum value after two months.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.12
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• pp.1839-1845
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• 2010

This study was conducted to evaluate the effects of salt soluble protein extracts from anchovy (ASSPE) on sausage during storage at $10^{\circ}C$. Sausages were produced containing 5 and 10% ASSPE. Sausages containing ASSPE showed no significant differences in emulsion stability, color, pH, moisture, viable cell count, and VBN compared to the control. The hardness significantly increased with the addition of ASSPE, and sausages containing 5% ASSPE were the highest in gumminess. In the sensory evaluation, sausages containing 5% ASSPE had the highest score in appearance and springiness. In conclusion, the addition of ASSPE in sausage had no effects on storage characteristics, but had a good effect on improvement of quality and sensory characteristics. Especially, 5% ASSPE sausage had good texture and high sensory characteristics due to increased binding capacity. These results suggest that 5% ASSPE may improve the quality and sensory characteristics of sausage.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.2A
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• pp.65-73
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• 2012

In this study, we tested structural performance of Half-Decked PSC girder which was developed for applying to long span bridge. We operated 4 point bending test with 60 m span full scale girder designed as simple bridge with hinge-roller boundary condition. Actuators were set on the both sides of girder, 5.5 m away from the center, and 4 stages of cyclic loading was applied at rate of 1 kN/sec. Through stages 1 to 4, loading and unloading 1,000 kN, 1,200 kN, 1,500 kN, and 2,000 kN were repeated and displacement, strain of concrete and steel, crack of girder were checked. From these results, the strength of girder was assessed and resilience and ductility were observed after removing the load. Since initial flexural crack occurred in the vicinity of 1,400 kN, non-linearity of load-displacement curve appeared and definite residual strain was measured at that point. The test result showed that initial cracking load was over twice the DB-24 load which means the developed girder had sufficient strength. To verify the experimental results, we numerically analyze the test and confirmed that the data were similar with results from the test above. Half-Decked PSC type of 60 m-girder developed in this study showed its adequate structural capacity through static loading test, which proved that possibility of applying the girder to actual bridges practically.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.5 s.39
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• pp.25-33
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• 2004

To evaluate the seismic capacity of a multistorey building structures in performance based seismic design, it is needed to convert MDOF model into equivalent SDOF model. This paper presents predictions for interstory drift of multistorey structures using method of converting a MDOF system into an equivalent SDOF model. The principal objective of this investigation is to evaluate appropriateness of converting method through performing nonlinear time history analysis of a multistory building structures and an equivalent SDOF model. Comparing the interstory drift of multistorey structures calculated by time history analysis and those evaluated by an equivalent SDOF model, the adequacy and the validity of converting method is verified. The conclusion of this study is following; A method of converting a MDOF system into an equivalent SDOF model through the nonlinear time history response analysis is valid. Inelastic first mode shapes are expected to be more accurate than elastic first mode shapes in obtaining interstory drift of multistorey structures from equivalent SDOF model.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.669-673
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• 2012

제방안전성 모니터링은 제방파괴로부터 국민의 생명과 재산을 보호하는데 필요한 정보를 얻을 수 있는 하나의 방법이 될 수 있다. 근래에 미국은 2005년 허리케인 카타리나에 의해 2,000여명의 인명손실을 경험하였고 2011년 3월 일본은 도후쿠지역의 초강력 지진에 의한 쓰나미로 인해 수만명의 인명과 후쿠시마 원자력 발전소의 침수로 지금까지 방사능 누출 차단작업을 벌이고 있다. 국내에서는 4대강 복원사업으로 주요 국가 하천 구간에서 홍수 및 체제 불안정에 의한 제방붕괴사고위험이 현격하게 줄어들었으나 제방의 안전성은 더욱 강조되고 있다. 즉 신설된 보 주변, 배수통문 신설구간 그리고 제방누수 예상지점 등에서는 아직 안전한 상태라고 확신할 수 없으며 지속적인 모니터링이 요구된다. 따라서 본 연구에서는 광섬유를 이용하여 개발한 간극수압 및 온도 센서 등을 위험예상지점에 설치하고 정보시스템을 통하여 어떻게 관리 할 것인가에 대한 사전 검토를 계획하였다. 이를 위하여 제방에 센서를 설치하기 전에 주요 검토사항에 대하여 연구분석하였다. 주요 검토사항에는 설치하고자 하는 지점의 제방거동 메커니즘 예측, 왜 계측시스템을 설치하는지에 대한 목적에 대한 평가, 설치 지점의 제방의 토질공학적 문제점 파악, 모니터링 대상 매개변수 혹은 항목 선정, 조사대상 항목의 변화정도를 예측하여 거동 범위 확정, 적정 계측기기 설치 지점을 선청, 계측기기 선정, 자동화 혹은 실시간 정보시스템에 필요한 사항 결정, 관측에 영향을 미치는 인자들의 기록 계획, 정보의 타당성 확보를 위한 필요사항 정립, 비용의 결정, 장기 예측 계획, 정기 검 보정 및 관리 계획, 자료수집 및 관리계획, 자원의 공조 및 생애주기 비용 등을 포함하였다.

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.1
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• pp.76-87
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• 2019

The purpose of this study was to evaluate the performance of and to derive future maintenance-management measures of the constructed alternative habitat for the Kaloula borealis at the University of Seoul, examining the period between 2015-2017. The research was constructed in 2014 and in a $191m^2$ area. The performance evaluation was divided into maintaining the habitat of the target species, maintaining the population and reproduction rates of the target species, maintaining the habitat of the wild species, the resilience of natural ecosystems, and the harmony with the surrounding environment. In terms of maintaining the habitat of the target species, soil collected from the existing habitat of the Kaloula borealis and was the depth was increased to 30cm in the alternative habitat. An artificial water supply was required every year during the supporting the spawning and hatching of other amphibians along with the Kaloula borealis. The sources of water of the alternative habitat were both rain and tap water, as it cannot be maintained naturally. Additionally, the Kaloula borealis thrived because it inhabited the research site and the average temperature was $26.2^{\circ}C$ from April-June, which is when the Kaloula borealis spawns. In terms of maintaining the population and reproduction rates of the Kaloula borealis, they were evaluated to have stable rates of reproduction. In terms of maintaining the habitat of the wild species, studies on vegetation and the structure of the characteristics of prey or predators will be needed. Also, alien species, such as Humulus japonicus and Bidens frondosa needed to be removed to maintain the wetland ecosystem of the wild species. In the assessment of the resilience of the natural ecosystems, the mud was monitored, noting the changes in the depth of water, with steps taken to reduce the leakage of water. The mud collected from the Haneul Pond wetland, which is located around the research site was piled up. Also, partial mowing management and the inducement of a natural vegetation colony was required for vegetation management. It was also necessary to create porous spaces, such as old trees and tree branches to create a habitat with hiding places and feeding and spawning places for small organisms. In terms of the harmony with the surrounding environment, the following threat factors needed to be managed: amphibian roadkill by vehicles and pedestrians and artificial draining due to nearby user access. Based on the monitoring results, alternative habitat management measures presented the promoting various waterside structures, in which amphibians can spawn and hide in, managing the water environment consistently, managing the vegetation, focused on the habitat of the wild species, and managing the surrounding environment for the habitat. The creation of an alternative habitat should be managed through monitoring, reflecting the characteristics of the changes in the site. Also continuing efforts are also needed to improve the habitat of the target species.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1819-1823
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• 2007

유역에서 상류 유역 또는 수변을 따라 자연 자원을 이용하여 조성되어야 할 완충지대는 비점오염의 영향을 줄이기 위한 중요한 최적 관리공법이다. 교란된 토지 피복과 수변 완충지대를 관리 및 복원할 때 같은 지형조건이라도 식생 종류, 발달정도, 토양조건에 따라 오염물 제거효과가 다를 수 있으며, 최소 완충지대 길이도 제거 오염물질 대상별로 적합하게 설계되고 해석되어야 한다. 본 연구의 목적은 용담댐 유역에서 SWAT 모델을 이용하여 식생 완충지대의 비점오염원 저감 모의 재현성을 평가하는 것이였다. 소유역의 관측값과 모델 예측값에 대한 모델의 검 보정이 선행되었으며 그 중에서 가장 높은 모델 효율을 가지는 소유역에서 three zone concept의 90m 수변완충지대를 지방하천을 경계로 하여 토지 피복도를 변화시켜 SWAT 모델에 적용하였다. 이 때 교목으로는 포플러 (Populus, 30m)을 적용하였고, 포플러의 높이 및 Leaf area index를 조정하여 관목 지대(30m)에 입력하였다. 잔디 지대(30m)는 자연초지를 선택하였다. 또한 지형변수(average slope)와 Manning's coefficient을 수변완충지대의 조건에 고려하여 변화를 주었고 이에 따른 유출량 및 유사량, T-N, T-P의 변화율을 조사하였다. 또한 5, 10, 30m의 식생 여과대를 밭 지역에만 적용하여 오염물의 저감 효율을 평가하였다. SWAT 모델은 각 소유역에서 발생된 전반적인 유출량과 수질변수의 추세를 잘 예측하였으며 정자천 소유역이 선택되었다. 모의된 완충지대에서는 연평균 940 m3/ha의 유출량이 감소되는 것으로 유사농도는 28.7 %의 저감효과를 보였다. 그러나 T-N, T-P의 농도는 오히려 증가되었는데 본 연구에서 고려된 보다 수변완충지대를 조성할 때 지하수 수위, 식생 성장변화 등과 같은 보다 정확한 설계 인자 산출 및 모델 DB 개발이 유역모델에 포함되어야 할 것으로 판단되었다.한 해결책을 얻어내는 상호보완적인 결과를 추구한다. 그가 디자인하는 작품은 전형적인 이미지를 내포하지 않는다. 즉 그의 작품은 기존의 가치와 이념적인 것은 배제하고, 창의적인 개념을 도출하였다.형모서리는 건물 특화 성격이 강하므로 불가피할 경우 소형 액센트 광고 위치를 미리 벽면으로 할애하는 것이 경관 및 입면계획에 유리한 것으로 분석되었다. 불확실도 해석모형 등의 새로운 기능을 추가하여 제시하였다. 모든 입출력자료는 프로젝트 단위별로 운영되어 data의 관리가 손쉽도록 하였으며 결과를 DB에 저장하여 다른 모형에서도 적용할 수 있도록 하였다. 그리고 HyGIS-HMS 및 HyGIS-RAS 모형에서 강우-유출-하도 수리해석-범람해석 등이 일괄되게 하나의 시스템 내에서 구현될 수 있도록 하였다. 따라서 HyGIS와 통합된 수리, 수문모형은 국내 하천 및 유역에 적합한 시스템으로서 향후 HydroInformatics 구현을 염두에 둔 특화된 국내 수자원 분야 소프트웨어의 개발에 기본 토대를 제공할 것으로 판단된다.았다. 또한 저자들의 임상병리학적 연구결과가 다른 문헌에서 보고된 소아 신증후군의 연구결과와 큰 차이를 보이지 않음을 알 수 있었다. 자극에 차이가 있지 않나 추측되며 이에 관한 추후 연구가 요망된다. 총대장통과시간의 단축은 결장 분절 모두에서 줄어들어 나타났으나 좌측결장 통과시간의 감소 및 이로 인한 이 부위의 통과시간 비율의 저하가 가장 주요하였다. 이러한 결과는 차가운 생수 섭취가 주로 결장 근위부를 자극하는 효과를 발휘하는 것이 아닌가 해석된다. 이와 같은 연구결과를 통해 생다시마를 주원료로 개발된 생다시마차와 생다시마 음료가 만성 기능성 변비 증세를 개선하는 효능이 잠재적으로 있음을 확인하였다. 그러나 생약제재의 변비약 수준으로 변비 개선 효능을 증대하기 위해서는 재료 배합비의 개선이나 대장 운동기능을 향상시키는 유효성분의 보강 등이 필요하다는 점도 알 수 있었다.더불어 산화물질 해독에 관