• 한국항해항만학회지
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• 제36권10호
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• pp.795-801
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• 2012

본 논문에서는 요트 계류장과 같은 소형 해상 부유체의 위기수준을 모니터링하기 위한 확률 기반 위기평가기법(Probability based risk Evaluation Techniques, PET)의 이론적인 접근 방법을 기술하였다. PET는 5단계 척도의 위기 기준을 이용한 위기 판단 절차가 핵심 개념이다. 이러한 5단계 척도들은 폐형 공식을 이용한 해상 부유체 운동의 응답함수에 대한 누적확률분포에서 계산했다. 그리고 위기기준을 갖는 PET의 위기판단 절차를 제안하였다. PET의 유용성 검증을 위하여 시뮬레이션 실험을 하였는데, 실험에는 해상 부유체의 운동 측정에 사용할 ADIS16405 센서의 전기특성을 갖는 모의 신호를 이용하였다. 실험결과, PET의 위기평가 오차는 최대 5.0 수준에서 0.38 수준으로 나타났다. 이 결과로부터 제안한 PET가 모니터링 기법으로 사용 가능함을 확인하였다.

• Smart Structures and Systems
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• 제15권6호
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• pp.1583-1600
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• 2015

When natural disasters occur, including earthquakes, tsunamis, and debris flows, they are often accompanied by various types of damages such as the collapse of buildings, broken bridges and roads, and the destruction of natural scenery. Natural disaster detection and warning is an important issue which could help to reduce the incidence of serious damage to life and property as well as provide information for search and rescue afterwards. In this study, we propose a novel computer vision technique for debris flow detection which is feature-based that can be used to construct a debris flow event warning system. The landscape is composed of various elements, including trees, rocks, and buildings which are characterized by their features, shapes, positions, and colors. Unlike the traditional methods, our analysis relies on changes in the natural scenery which influence changes to the features. The "background module" and "monitoring module" procedures are designed and used to detect debris flows and construct an event warning system. The multi-criteria decision-making method used to construct an event warring system includes gradient information and the percentage of variation of the features. To prove the feasibility of the proposed method for detecting debris flows, some real cases of debris flows are analyzed. The natural environment is simulated and an event warning system is constructed to warn of debris flows. Debris flows are successfully detected using these two procedures, by analyzing the variation in the detected features and the matched feature. The feasibility of the event warning system is proven using the simulation method. Therefore, the feature based method is found to be useful for detecting debris flows and the event warning system is triggered when debris flows occur.

• 한국물환경학회지
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• 제31권3호
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• pp.286-294
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• 2015

Temporal and spatial characteristics of cyanobacterial communities at the monitoring stations for Harmful Algal Bloom Alert System (HABAS) in Nakdong River and Lake Dukdong were investigated for two years (2013 to 2014). A total of 30 cyanobacterial species from 14 genera were found at the survey stations. Microcystis sp. showed maximum cell density in the total cyanobacterial community in August, 2014 at ND-2 and in September, 2013 at ND-3 station. Lynbya limnetica and Geitlerinema sp., non-target species for alert criteria showed maximum cell density at ND-1 (August, 2013) and Dam station of Lake Dukdong (September, 2014), respectively. Total cyanobacterial cell density and the relative abundance of four target genera (Microcystis, Anabaena, Aphanizomenon and Oscillatoria spp.) for alert criteria was relatively lower in the mesotrophic Lake Dukdong than at the eutrophic riverine stations of Nakdong River, indicating cyanobacterial density and the RA of target genera is affected by the trophic state of the monitoring stations. Simulating the alert system using phycocyanin concentration as an alert criterion resulted in the longer period of alert issued compared to the period of alert issued using the current criterion of harmful cyanobacterial cell density due to the influence of phycocyanin concentration from non-target cyanobacterial species.

• 한국환경농학회지
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• 제31권1호
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• pp.75-95
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• 2012

BACKGROUND: Increase of heavy metals in agricultural ecosystem has become a social issue nationwide as it is related to public health. This review was performed to find out more systematic and integrated future researches on heavy metals using up to date articles published in the Korean journals related to agricultural environment. METHODS AND RESULTS: Researches on heavy metals in agricultural soils and plant uptake were categorized by the establishment of criteria, analytical methods, monitoring, management of source, characteristics and behavior in soil, plant uptake, bioavailability affecting physico -chemical properties in soil, risk assessment and soil remediation. In the early 1990s, the monitoring for heavy metals in soil has been widely performed. Accumulation of heavy metals in contaminated soil and availability to plants has also attracted interests to study the soil remediation using various physico-chemical methods. The phytoavailability and phytotoxicity of heavy metals have been mainly studied to assess the safety of agro-products using risk assessment techniques in the 2000s. CONCLUSION: Future direction of research on heavy metal in agricultural environment must be carried out by ensuring food safety and sustainability. A steady survey and proper management for polluted regions should be continued. Law and regulation must be modified systematically. Furthermore, studies should expand on mitigation of heavy metal uptake by crops and remediation of polluted fields.

• 한국물환경학회지
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• 제31권5호
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• pp.563-568
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• 2015

Natural Organic Matter (NOM) is a precursor of disinfection by products. Recently, with the increase in NOM concentration caused by a large amount of algae, the creation of disinfection by-products is becoming a big issue. Therefore, in this study, PAC+Membrane+F/A hybrid process was organized to control disinfection by-products in small-scale water treatment plants. The optimal dosage of PAC was set at 20 mg/L through Lab. scale test. Also, it is judged that NOM concentration must be less than 1.0 mg/L to meet the recommended criteria of drinking water quality monitoring items of disinfection by-products during chlorination. The existing conventional water treatment process was compared to the independent F/A process and the PAC+Membrane+F/A hybrid process through pilot plant operation, and the result showed that there is a need to apply an advanced water treatment process to remove not only NOMs but also Geosmin caused by algae. Accordingly, it is considered that applying the PAC+Membrane+F/A process will help in controling a clogged filter caused by a large amount of algae and disinfection by-products created by chlorination and can be used as an advanced water treatment process to meet the recommended criteria of drinking water quality monitoring items.

• Geomechanics and Engineering
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• 제8권2호
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• pp.153-171
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• 2015

The observational method in tunnel engineering allows the evaluation in real time of the actual conditions of the ground and to take measures if its behavior deviates considerably from predictions. However, it lacks a consistent and structured methodology to use the monitoring data to adapt the support system in real time. The definition of limit criteria above which adaptation is required are not defined and complex inverse analysis procedures (Rechea et al. 2008, Levasseur et al. 2010, Zentar et al. 2001, Lecampion et al. 2002, Finno and Calvello 2005, Goh 1999, Cui and Pan 2012, Deng et al. 2010, Mathew and Lehane 2013, Sharifzadeh et al. 2012, 2013) may be needed to consistently analyze the problem. In this paper a methodology for the real time adaptation of the support systems during tunneling is presented. In a first step limit criteria for displacements and stresses are proposed. The methodology uses graphics that are constructed during the project stage based on parametric calculations to assist in the process and when these graphics are not available, since it is not possible to predict every possible scenario, inverse analysis calculations are carried out. The methodology is applied to the "Bois de Peu" tunnel which is composed by two tubes with over 500 m long. High uncertainty levels existed concerning the heterogeneity of the soil and consequently in the geomechanical design parameters. The methodology was applied in four sections and the results focus on two of them. It is shown that the methodology has potential to be applied in real cases contributing for a consistent approach of a real time adaptation of the support system and highlight the importance of the existence of good quality and specific monitoring data to improve the inverse analysis procedure.

• 농촌지도와개발
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• 제21권4호
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• pp.1191-1226
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• 2014

FAO의 세계중요농업유산(GIAHS) 및 국가중요농업유산(Agricultural and Rural Heritage)은 탁월한 보편적 가치뿐만 아니라 농촌의 지역경제 활성화와 농촌발전의 대안으로 그 중요성이 인식되고 있다. 본 연구는 이와 같은 농업 농촌유산을 지속가능하게 유지하고 보전할 수 있는 평가지표를 개발하고자 이루어졌다. 이를 위해 문헌분석을 통해 평가요소를 도출하고, 도출된 평가요소들을 체계화하여 평가항목과 평가지표를 구안하였다. 구안된 평가항목과 평자지표의 타당화를 위해 농업 농촌유산 관련 전문가 41명을 대상으로 총 3차의 델파이조사를 실시하였으며, 그 결과 5항목 31지표의 평가지표를 개발하였다. 평가항목의 경우 관리계획, 관리지원체계, 유산의 주변환경, 지역네트워크, 유산활용 중에서 관리지원체계가 가장 중요한 것으로 나타났으며, 평가지표의 경우 보전정비, 수행계획, 주민공동체 구성, 모니터링, 법령조례의 구비, 생태계관리, 경관적 조화성, 복원 및 전승계획, 주민역량강화 등의 순으로 그 중요성이 나타났다. 이는 국가중요농업유산 및 세계농업유산 지정 등 지역의 잠재적 문화가치를 창출하는데 기여할 수 있으며, 또한 다원적 자원을 활용한 지역개발사업 및 마을 소득화사업 추진시 탄력적으로 실무 적용할 수 있을 것으로 사료된다.

• 한국대기환경학회지
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• 제17권5호
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• pp.395-405
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• 2001

To make an assessment of the compatibility between DOAS and conventional point monitoring system (MCSAM-2: MS2), we investigated the concentrations of three criteria pollutants which include S $O_2$, N $O_2$, and $O_3$from a national monitoring station in Seoul during the periods of June 1999~August 2000. The average concentration values for the whole study period derived from hourly concentration data sets of those three species indicated that the mean differences between the two methods can be approximated as 18%. When the bias structure of two systems was evaluated through the computation of percent difference(PD) between the two such as ( $C_{DOAS}$- $C_{conventional}$ $C_{DOAS}$*100, differences between the two systems appeared to be quite systematic among different compounds. While the mode of bias peaked at 0~20% or 20~40% in terms of PD values, the cause of such positive bias mainly arised from generally enhanced concentration values of DOAS system. The structure of bias among different species was further assessed through linear regression analysis. Results of the analysis indicated that the dominant portions of differences observed from two monitoring systems can be accounted for by the systematic differences in their spanning and zeroing systems. S $O_2$(MS2)=0.6385 S $O_2$(DOAS)+2.0985($r^2$=0.7894) N $O_2$(MS2)=0.6548 N $O_2$(DOAS)+7.437($r^2$=0.7687) $O_3$(MS2)=1.0359 $O_3$(DOAS)-7.7885($r^2$=0.7944) The findings of slope values at around 0.64~0.65 from two species suggest that DOAS should respond more sensitively in upper bound concentration range. The offset values apart from zero indicate that more deliberate comparison needs to be made between these monitoring systems. However, based on the existence of strong correlations from at least 8,000 data points for each species of comparison, we were able to conclude that the compatibility of two monitoring systems is highly significant. With the improvement of calibration techniques for the DOAS system. its applicability for routine monitoring of airborne pollutant species is expected to be quite extendable.

• Earthquakes and Structures
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• 제19권1호
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• pp.29-44
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• 2020

The effectiveness and the sensitivity of a Wireless impedance/Admittance Monitoring System (WiAMS) for the prompt damage diagnosis of two single-storey single-span Reinforced Concrete (RC) frames under cyclic loading is experimentally investigated. The geometrical and the reinforcement characteristics of the RC structural members of the frames represent typical old RC frame structure without consideration of seismic design criteria. The columns of the frames are vulnerable to shear failure under lateral load due to their low height-to-depth ratio and insufficient transverse reinforcement. The proposed Structural Health Monitoring (SHM) system comprises of specially manufactured autonomous portable devices that acquire the in-situ voltage frequency responses of a network of twenty piezoelectric transducers mounted to the RC frames. Measurements of external and internal small-sized piezoelectric patches are utilized for damage localization and assessment at various and increased damage levels as the magnitude of the imposed lateral cycle deformations increases. A bare RC frame and a strengthened one using a pair of steel crossed tension-ties (X-bracing) have been tested in order to check the sensitivity of the developed WiAMS in different structural conditions since crack propagation, damage locations and failure mode of the examined frames vary. Indeed, the imposed loading caused brittle shear failure to the column of the bare frame and the formation of plastic hinges at the beam ends of the X-braced frame. Test results highlighted the ability of the proposed SHM to identify incipient damages due to concrete cracking and steel yielding since promising early indication of the forthcoming critical failures before any visible sign has been obtained.

• 한국임상약학회지
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• 제20권2호
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• pp.151-158
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• 2010

Therapeutic drug monitoring of Mycophenolate mofetil(MMF) has been suggested in some clinical trials, but has not been widely adopted in Korea. The purpose of this study was to analyze the withdrawal rates of MMF and determine the characteristics of the patients who experienced adverse reactions with MMF therapy and to suggest the criteria for selecting patients who need monitoring of MMF levels. We retrospectively collected data of patients who started MMF between July 2007 and June 2008. A total of 154 adult patients were included in our study. Among them, ninety seven patients discontinued MMF with 59 cases being due to adverse drug reactions. Thirty one patients required dosage reduction of MMF with twenty three cases being due to adverse reactions. Twenty six patients continued the MMF without or with mild adverse reactions. Of the 82 adverse reaction cases, hematologic adverse reactions accounted for 38 cases (46%) and gastrointestinal (GI) adverse reactions accounted for 28 cases (34%). Older age and lower serum albumin levels were significantly different characteristics between the patients who withdraw MMF due to hematological adverse reactions and those who were able to continue therapy. The group who experienced GI adverse reactions had higher MMF dosages based on body weight and lower serum albumin levels. In conclusion, the factors affecting the adverse reactions of MMF were age, serum albumin level and higher dosage, therefore therapeutic drug monitoring of MMF should be considered in these patients.