• Journal of Wetlands Research
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• v.21 no.2
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• pp.181-190
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• 2019

Recently, Low impact development techniques, a form of nature-based solutions (NBS), were seen cost-efficient alternatives that can be utilized as alternatives for conventional stormwater management practices. This study evaluated the effectiveness of an infiltration trench (IT) and a small constructed wetland (SCW) in treating urban stormwater runoff. Long-term monitoring data were observed to assess the seasonal performance and cite the advantages and disadvantages of utilizing the facilities. Analyses revealed that the IT has reduced performance during the summer season due to higher runoff volumes that exceeded the facility's storage volume capacity and caused the facility to overflow. On the other hand, the pollutant removal efficiency of the SCW was impacted by the winter season as a result of dormant biological activities. Sediment data also indicated that fine and medium sand particles mostly constituted the trapped sediments in the pretreatment and media zones. Sediments in SCW exhibited a lower COD and TN load due to the phytoremediation and microbiological degradation capabilities of the system. This study presented brief comparison LID facilities equipped with pre-treatment zones. The identified factors that can potentially affect the performance of the systems were also beneficial in establishing metrics on the utilization of similar types of nature-based stormwater management practices.

• The Journal of Engineering Geology
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• v.34 no.2
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• pp.163-171
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• 2024

Changes in the soil layer on Dokdo are important both academically and with regard to sustainable conservation and utilization of the islands. Continuous investigation and observation are necessary, as the soil layer is essential to the growth of plants and, therefore, the islands' ecosystem. Such work was carried out for about 8 years using soil erosion measuring bars, which are durable and facilitate simple monitoring of changes in the soil layer. Each bar comprised a rod measuring 30~50 cm long and 1.5 cm in diameter, and the use of stainless steel afforded resistance to corrosion caused by sea breezes. Six measuring bars were installed in the soil layers of each of two islands, Dongdo and Seodo, and measurements were taken one to three times a year from 2014 to 2021. The field measurements indicate that soil was deposited on Dongdo but eroded on Seodo during the observation period. As the measuring bars on Dongdo were located in the central and lower parts of the island, the observed changes in the soil layer resulted mainly from sedimentation of material eroded by weathering or soil runoff from the upper part of the island. In contrast, the measurement locations on Seodo were located in the upper and central parts of the island, where soil erosion and runoff diminished the soil layer at the observation points.

• Journal of the Korean GEO-environmental Society
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• v.16 no.1
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• pp.29-36
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• 2015

Current domestic research is to demonstrate the effectiveness and efficiencies of flood prevention measures through one-dimensional numerical analysis and this study's object is to help water managers to make the efficient decisions by applying the two-dimensional urban run off model XP-SWMM model in the flooded area and comparing with the flood prevention measures. Statistics were analyzed, based on the data collected from Cheongju Weather Service from 1967 to 2011 for 45 years. 50 years Flood frequency simulations of water flow capacity analysis of the target area for flooded areas $539,548m^2$, inundation depth 1.0 m, was analyzed by inundation time of 48 minutes. When comparing with the constructions of bypass road and underground storage facilities to increase the water flow capacity of A1 small drainage areas as flood protection, if you install a batching target underground detention basin with a capacity of $13,500m^3$, it is expected that the flood by rainfall with frequency of 50 years will be resolved completely. In preparation for extreme weather in the future flood mitigation measures, underground storage tank installation is considered a better efficient way.

• Journal of KIISE:Databases
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• v.27 no.1
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• pp.42-52
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• 2000

In many real time applications that the system maintains sensitive information to be shared by multiple users with different security levels, security is another important requirement. A secure real time database system must satisfy not only logical data consistency but also timing constrains and security requirements associated with transactions. Even though an optimistic concurrency control method outperforms locking based method in firm real time database systems, where late transactions are immediately discarded, most existing secure real time concurrency control methods are based on locking. In this paper, we propose a new optimistic concurrency control protocol for secure real time database systems, and compare the performance characteristics of our protocol with locking based method while varying workloads. The result shoes that our proposed O.C.C protocol has good performance in case of many data conflict.

• Spatial Information Research
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• v.20 no.3
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• pp.67-81
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• 2012

Due to the recent advancement of cloud computing, the research on database outsourcing has been actively done. Moreover, the number of users who utilize Location-based Services(LBS) has been increasing with the development in w ireless communication technology and mobile devices. Therefore, LBS providers attempt to outsource their spatial database to service provider, in order to reduce costs for data storage and management. However, because unauthorized access to sensitive data is possible in spatial database outsourcing, it is necessary to study on the preservation of a user's privacy. Thus, we, in this paper, propose a spatial data encryption scheme to produce outsourced database from an original database. We also propose a k-Nearest Neighbor(k-NN) query processing algorithm that efficiently performs k-NN by using the outsourced database. Finally, we show from performance analysis that our algorithm outperforms the existing one.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.253-257
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• 2010

최근 들어 이상 강우 현상으로 인한 기록적인 집중 강우와 더불어 토지 이용 변화로 인해 탁수의 발생 빈도가 증가하고 있다. 강우 유출로 유입한 탁수는 저수지 내 장기간 체류하면서 하류 하천의 수질 및 수생태계 뿐만 아니라 저수지 내부의 영양단계에도 많은 영향을 준다. 특히, 성층화된 저수지의 경우 높은 영양염류 농도를 포함한 탁수는 밀도류 거동 특성을 보이면서 수평 및 수직 혼합 과정을 거치면서 국부적인 부영양화 현상과 조류의 수화 현상의 원인이 되고 있다. 따라서 대형 저수지의 수질관리에 있어 하천 유입 탁수의 밀도류 해석, 저수지의 수온 성층 구조 변화, 부유입자의 동력학적 해석이 중요한 요소로 부각되어 왔다. 본 연구에서는 소양호를 연구 대상 지역으로 선정하여 2005년과 2007년 수문 사상을 바탕으로 2차원 횡방향 수치 모형을 구축하였다. 수치모형을 통해 수온 성층 구조의 재현성을 확인하였으며, 다양한 탁수 거동 모형을 구축하여 적용성을 평가하였다. 유입수의 SS(Suspended Solid)를 단일 입경으로 가정한 TM-1 모형, SS의 입경분포에 따라 3개의 그룹(SSi)으로 구분한 TM-2 모형, 3개 그룹을 포함하면서 저수지내 탁수 장기화로 인한 탁수 저감 효과를 1차 반응상수로 매개 변수화(유기물 함량($a_0$) ${\times}$ 분해속도(${\lambda}_a$))하여 수정된 지배방정식을 적용한 TM-3 모형을 사용하였다. 각각의 탁수 거동 모형은 2005년과 2007년 수문 조건에서 수온 성층 구조를 잘 재현하였다. TM-1 모형과 TM-2 모형을 비교해보면, 탁수 중심축의 최고 탁도에 대한 예측 성능은 TM-2 모형이 우수한 결과를 나타냈었다. 하지만, 장기 탁수 모의 시 저수지 수중 잔류 SS가 지속적으로 높게 나타나 중층 탁도를 과대평가하는 경향을 보였다. TM-3 모형이 TM-2 모형에 비해 수심별 탁도 분포에 대한 중심축 탁도가 저평가되는 경향을 보였지만 저수지 내 잔류 탁도에 대한 영향 부분에서는 개선된 결과를 나타내었다. 본 연구 결과는 저수지 탁수 밀도류 해석 및 운영 시스템에 활용 될 수 있으며, 선택 취수 설비 등의 수리 구조물의 영향 평가에 활용할 수 있다.

• Journal of the Korea Institute of Building Construction
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• v.22 no.6
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• pp.607-618
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• 2022

This study involves the development of a Hwangto permeable block for rainwater storage tanks. The permeable products that form continuous voids between Hwangto binders and aggregates are fine milled slag powder, which is an industrial by-product generated during the production of Hwangto and iron, and ferro nickel slag. The properties of Hwangto permeable blocks were studied using recycled resource aggregates. The target quality is based on KSF 2394. The Hwangto permeable block for a rainwater storage tank is made of water-permeable material, and the permeability of the Hwangto permeable block itself is 0.1mm/sec or higher, with a physical performance of over 5.0MPa in flexural strength and over 20.0MPa in compressive strength. The physical properties of Hwangto permeable block for rainwater storage tanks were researched and developed. In order to prevent flooding due to heavy rain in summer and the urban heat island phenomenon due to depletion of ground water, continuous pores are formed in the block to secure a permeability function to prevent rainwater from accumulating in the pavement of the floor, and to prevent slippage for comfortable and safe storage.

• Proceedings of the Technology Innovation Conference
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• 2002.02a
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• pp.205-221
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• 2002

본 연구의 목적은 정부출연연구소에서 연구개발된 기술이 민간부문에서 충분히 활용되지 못하고 있다는 문제의식으로부터 출발하여, 원천, 핵심기술의 확보가 국가경쟁력을 좌우하는 첨단기술경제시대에 막대한 국가자금으로 연구개발된 우수한 기술의 사장을 방지하고 궁극적으로 국가경제발전을 위한 전략적 기술이전 촉진 방안을 모색하는 것이다. 현재 국무총리산하 기초, 산업, 공공기술 연구회로 분류 조직되어 있는 3개 연구회 총 1개 정부출연연구소의 지난 10년간(1992-2001)의 연구예산규모, 보유특허수, 기술이전건수, 기술징수액, 기술실시계약서를 방문 조사하고 각 연구소의 기술이전전담조직의 실무자를 대상으로 설문 조사하여 설문 및 통계분석 결과를 토대로 기술이전관련 문제점 파악 및 기술이전 촉진을 위한 전략적 개선방안을 모색해 보았다. 먼저 기술이전 현황을 살펴보면 기술이전건수는 보유특허수의 3%미만, 기술료 징수액은 연구예산규모의 2%미만으로 기술이전 및 기술상업화율이 상당히 저조하다. 설문 및 통계분석 결과로부터 TLO 조직의 비효율적인 운영, 비전문성, 열악한 운영인력, 적극적인 기술이전을 위한 동기부족, 정부의 제도적인 지원부족, 기술실시계약서 조항들의 경직성 등을 기술이전 관련 문제점으로 도출해 낼 수 있었다. 이러한 문제점을 극복하고 기술이전 촉진을 위한 개선방안으로는 첫째, TLO 조직을 전략으로 개편해야 한다. 즉 기술이전 전담인력을 변리사, 전문 협상가, 연구원 둥 전문가들로 구성하여 지적재산권 관리, 기술평가, 시장조사, 기술마케팅, 사후관리 등을 효율적으로 수행해야 한다. 둘째, 정부의 정책적인 지원이 필요하다. 기술이전 전담조직에 대한 인센티브 시스템 기술이전을 위한 특별예산 편성 등을 정책적, 제도적으로 도입하는 등의 적극적인 지원이 요구된다. 셋째, 기술실시계약서 조항들을 기술실시자의 실질적인 기술 상업화에 도움이 되고 기술 유출 및 기술사장화를 방지하는 방향으로 개선하여야 한다. 특히, 전용실시권과 실시대가, 기술실시 및 지적재산권 관리와 관련된 제반 비용의 부담비율 등을 보다 유연하게 개선하여야 한다. 본 연구는 정부출연연구소에서 민간부문으로의 기술이전만을 고려하여 기술이전의 중요한 요소인 민간부문에 대한 고려가 전혀 없다. 따라서 보다 실질적이고 체계적인 결과를 도출하기 위해 민간부문을 고려한 연구가 진행되어야 한다고 생각한다.

• Journal of Wetlands Research
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• v.6 no.4
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• pp.59-69
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• 2004

Constructed wetlands are regarded as an important water treatment system for agricultural water quality improvement and management. The purpose of this study is to evaluate the application of subsurface flow wetland(SFW), using the Pharagmites australis as macrophytes, and to clarify the basic and essential factors to be considered in the construction and management of constructed wetlands. This study was carried out relatively short hydraulic residence time(HRT), 6hr ~ 72hr (3days), using eutrophic reservoir water with relatively low concentrations of influent and large quantity to be treated. The effluent satisfied the criteria of agricultural water quality. Removal efficiencies of Biochemical oxygen demand(BOD), Chemical oxygen demand(COD), Suspended solids(SS) and Chlorophyll a(Chl-a) were high in HRT 24hr, not any more significant increasement of removal efficiencies in HRT 48hr and 72hr. However, removal efficiencies of nitrogen and phosphorus increased as HRT increased, showing the highest efficiency at the 72hr of HRT in nitrogen, and 48hr in phosphorous. The SFW was very effective system for reservoir water quality improvement, and had the advantages of the reduction of purchasing cost to land required, lack of odors, and harmful insects, especially mosquito, the improvement of the scenic beauty and minimal risk of public exposure. Therefore, it was evaluated that the SFW was very available water treatment system for the water quality improvement of agricultural reservoir. However, it was need to consider with application of the SFW in high cost of construction and troublesome of management.

• Journal of the Korean Society of Radiology
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• v.85 no.4
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• pp.746-753
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• 2024

Purpose This study aims to evaluate the incidence and management of venous ruptures after percutaneous transluminal angioplasty (PTA) for dysfunctional arteriovenous (AV) access. Materials and Methods From January 1998 to December 2015, 13506 PTA, mechanical thrombectomy, and thrombolysis procedures were performed in 6732 patients. The venous rupture rate following PTA was obtained, and access circuit primary patency (ACPP) was compared according to the etiology (PTA, thrombotic occlusion, and treatment type) of the venous rupture present. Results Venous rupture developed in 604 of the 13506 procedures. Venous ruptures were more frequent in female, AV graft cases, and in cases accompanied by thrombosis. Balloon tamponade was performed in 604 rupture cases, and stents were deployed in 119 cases where contrast extravasation and flow stasis persisted. ACPP was significantly better in the non-ruptured AV access circuits than in the ruptured group. However, AV access type and thrombosis was not associated with primary patency. In ruptured cases, ACPP is 8.4 months for prolonged balloon tamponade and 11.2 months for bare-metal stent insertion, showing statistically significant difference. Conclusion Balloon tamponade and bare-metal stent placement are effective treatment for PTA-induced venous ruptures. In particular, stent placement showed a similar ACPP to that of non-ruptured AV access circuits.