Deep learning based harmful algal blooms modeling in inland water using multimodal monitoring

권도혁 울산과학기술원 Ulsan National Institute of Science and Te 2026 국내박사

Photo-stimulated atomic engineering in two-dimensional materials for multifunctional sensors

Min Hyeok Lim 고려대학교 대학원 2026 국내석사

This thesis presents a facile sensing platform for real-time, distributed, and field-deployable water quality monitoring, addressing limited real-time responsiveness, insufficient spatial resolution, and poor suitability for continuous observation that constrain conventional approaches based on on-site sampling followed by laboratory analysis. In this study, we adopted a facile and mask-free methodology to fabricate spiral-structured laser-induced graphene (LIG) directly on polyimide substrates via site-specific CO2 laser irradiation under ambient conditions, enabling ultrafast fabrication with high process flexibility. The resulting LIG exhibits a three-dimensional porous nanostructure, tunable wettability governed by surface energy, and high sensitivity, thereby enabling effective detection of chloride ions, copper ions, and pH variations. To validate practical applicability, the LIG was further integrated into an origami-inspired floating platform that operates without full immersion, enabling stable sensing at the air–water interface. This floating architecture minimizes water flow-induced disturbances and offers high compatibility with drone-assisted deployment for multipoint measurements over large areas. Sensing experiments distinctly verified fast response characteristics, excellent linearity, and high sensitivity within environmentally relevant concentration ranges, achieving detection limits of 0.05 ppm for chloride ions, 0.1 ppm for copper ions, and an equivalent limit of approximately 100 ppm for pH-related sensing. Notably, consistent sensing performance was well retained under diverse operating modes, entailing dropping, dipping, floating, and drone-assisted measurements, ascertaining robust operation in practical environments. Furthermore, field demonstrations employing drone-based deployment unequivocally validated spatially resolved mapping of water-quality distributions, highlighting the capability of the proposed platform as a viable tool for autonomous and real-time environmental monitoring. Overall, this work proposes an expandable and multifunctional environmental sensing paradigm that integrates LIG with floating sensor architectures and aerial deployment strategies for next-generation water quality monitoring systems. 본 학위논문은 현장 시료 채취 후 실험실 분석에 의존하는 기존 수질 오염 모니터링 방법의 실시간 응답성 부족, 공간 해상도 한계, 연속 관측의 부적합성과 관련된 제약을 해결하기 위해, 실시간, 분산, 현장 배치형 수질 오염 모니터링을 위한 유용한 센싱 소재 및 이를 기반으로 한 플랫폼 개발을 제시함. 본 연구에서는 상온, 대기 조건에서 영역 선택적 CO2 레이저 조사를 통해 폴리이미드 기판위에 나선형 구조의 레이저 유도 그래핀을 직접 제작하는 마스크-프리 공정을 적용하였으며, 이를 통해 초고속 제작과 높은 공정 유연성을 확보하였음. 제작된 LIG는 3차원 다공성 나노구조, 표면 에너지에 의해 결정되는 조절 가능한 젖음성 및 높은 감도를 나타내어 염화이온, 구리이온 및 pH 변화의 효과적인 검출을 가능하게 함. 실환경 적용성을 검증하기 위해, LIG는 완전 침수 없이 동작하는 종이접기 기반 부유형 플랫폼에 통합되었고, 이를 통해 공기-물 계면에서 안정적인 센싱이 가능하도록 설계되었음. 해당 부유형 구조는 물 흐름에 의한 교란을 최소화하며, 드론 기반 플랫폼과의 높은 호환성을 확보함으로써 넓은 영역에서의 다지점 측정을 가능하게 함. 센싱 실험 결과, 제안된 플랫폼은 환경적으로 의미 있는 농도 범위에서 빠른 응답 특성, 우수한 선형성, 높은 감도를 명확히 확인하였으며, 검출한계는 염화이온 0.05 ppm, 구리이온 0.1 ppm, pH 관련 센싱에 대해 약 100 ppm 수준의 검출한계를 달성하였음. 또한 낙하, 담금, 부유, 드론 기반 통신 모듈 집적화 측정 등 다양한 운용 모드에서도 일관된 센싱 성능이 유지되어 실환경에서의 견고한 동작성능을 확인하였음. 또한 드론 기반 현장 실증을 통해 수질 분포의 공간 분해 맵핑이 가능함을 확인하였으며, 제안된 플랫폼이 실시간 환경 모니터링을 위한 유효한 방법임을 확인하였음. 종합적으로 본 연구는 LIG와 부유형 센서 아키텍처, 드론 기반의 통신 시스템을 연계한 확장 가능하며, 다기능의 환경 센싱 패러다임을 제시하며, 차세대 수질 오염 모니터링 시스템을 위한 실용적 접근을 제공함.

화포천 화포습지의 수질정화능 평가

한성백 인제대학교 대학원 2007 국내석사

본 연구에서는 화포천의 수질 모니터링을 하며 습지가 수질에 미치는 영향에 대해 조사를 하였다. 화포천 본류 구간에서 설창교는 습지 유입부에 위치하고 화포교는 습지의 유출부에 위치한다. 수질 조사 지점 중 하천형 습지(riparin wetland)가 발달해 있는 2개 조사 지점에서 수질 측정 결과를 놓고 보았을때 화포천 습지의 영향을 평가해 볼 수 있다. 2005년 3월부터 2006년 3월까지 총 39회 측정한 결과에서 설창교와 화포교의 BOD, COD, TN, TP, NH4, NO2, NO3, PO4 등의 평균농도를 보면 화포교는 설창교 보다 농도가 다소 감소함을 알 수 있었다. 일반적으로 오염원이 산재해 있는 소하천이나 소규모 유역에서는 상류에서 하류로 갈수록 수질오염도는 일반적으로 증가하는 것이 보통이나, 화포습지의 영향으로 인해 화포교의 수질이 설창교보다 나음을 알 수 있다. 평균적으로 BOD는 18%, COD는 2.6%, TN 12%, TP 32% 감소한 수치를 보였으며, 무기물질의 경우 NH4는 22%, NO2는 24%, NO3는 19%, PO4는 52%로 유기물질보다 무기물질의 농도가 더 큰 폭으로 감소됨을 알 수 있었다. 습지의 정화능이 좋은 2005년 5~7월과 2006년 1~3월은 chl-a 농도가 높아지는 시기와 일치함을 알 수 있으며 평균적으로 화포천의 chl-a의 농도가 설창교보다 2배정도 높아 화포습지의 정화능에 있어 조류(algae)가 상당 부분 기여하는 것을 간접적으로 알 수 있다. 결과적으로 습지에서 감소한 오염물질은 입자 침강등의 작용으로 오염물질이 감소한 부분과 주변 식생의 성장과 조류의 증식으로 인해 흡수 저감된 부분으로 구별할 수 있을 것이다. This study was research about effect water quality was Influenced by wetland doing water quality monitoring. In the main stream section of Hwapo stream, Seolchang bridge was situated wetland inflow part and Hwapo bridge was situated wetland outflow part. In the two monitoring point was developed riparin wetland among water quality monitoring point, water quality measurement result looked effect of Hwapo wetland. From march, 2005 to march, 2006, All 39th measurement result is showed that concentration of Hwapo bridge is more decreased than that of Seolchang bridge - average concentration of BOD, COD, TN, TP, NH4, NO2, NO3, PO4 in the Seolchang bridge and Hwapo bridge. Usually cause of pollution scattered in the small river or small watershed, pollution degree of water quality in the downstream more increased than that of the upstream. But water quality of Hwapo bridge had better than that of Seolchang bridge because there was Hwapo wetland. Averagely BOD was decreased 18%, COD : 3%, TN : 11%, TP : 32%. In the concentration of Inorganic matter- NH4 was decreased 22%, NO2 : 24%, NO3 : 19%, PO4 : 51%-is far more decreased than that of organic matter. May ∼ July, 2005 and January ∼ march, 2006 was good the purification capability of wetland, concentration of chl-a rised in this period. Usually chl-a concentration of Hwapo stream was nearly twice as high as that of Seolchang bridge, the purification capability of Hwapo wetland was affected by algae indirectly. As a result, decrease of pollution matter in wetland was devided into particle sedimentation and the growth of vegetation and algae around Hwapo wetland.

수질환경 모니터링을 위한 자율주행 로봇의 위치경로 탐색과 자세제어에 관한 연구

김국세 조선대학교 대학원 2010 국내박사

이동 로봇이 주행하고 주변 환경을 인식하며 자기 위치를 추정하는 것은 매우 기본적이면서 중요한 기술들이다. 또한 단일 센서만 사용할 경우 주행에 필요한 정보나 주변 환경정보에 대해서 부정확한 계산결과를 낳을 수 있어서 여러 가지 다른 종류의 센서를 같이 사용하게 되는데 이때는 센서 융합기술도 필요하게 된다. 산업현장 뿐만 아니라 가정에서도 사람을 대신하여 작업을 해주는 청소로봇, 경비로봇 등 많은 서비스 로봇이 개발되고 있고, 연구소와 기업 등에서 연구 개발이 활발히 이루어지고 있다. 오늘날 기상이변이나 환경오염에 대한 심각성이 커져가고 있는 가운데 강이나 댐과 같은 저수조의 오염은 인간의 삶을 파멸로 가져올 수 있다. 강이나 하천 저수조 같은 곳에서 자율적으로 움직이면서 기상 데이터 및 수질 오염의 척도를 실시간으로 조사해서 모니터링 하여 전송할 수 있는 로봇 연구가 필요하게 되었다. 최근에는 작업의 요구 수심이 깊어지고 원격제어 및 통신 기술이 눈부시게 발전함에 따라 수상 작업 기술이 다양하게 이루어지고 있다. 수상 자율주행, 자세제어 로봇은 강이나, 하천, 저수조 그리고 해상의 다양한 환경에 적응하면서 사용자가 원하는 데이터를 수집하여 정보를 전송 제공해 준다. 이러한 역할을 하기 위한 로봇을 만들기 위해 필요한 기술들은 목표지점으로 이동하는 이동기술, 환경적응기술, 통신기술, 정보체취기술, 에너지절감기술 등 모든 것을 현 상황에 맞게 적용하고 판단하는 기술들이 필요하다. 이러한 기술을 다시 세부적으로 나눠보면 자율주행, 내비게이션, 위치인식, 장애물회피, 자세제어, 통신, 저전력 배터리 사용, 센서데이터 수집 및 모니터링 그리고 환경에 대한 적응적 지능이 필요하다. 여러 기술들이 복합적으로 작용하여 기술복합체로서 수상용 환경 모니터링 제어 로봇이 만들어진다. 본 연구논문에서는 이러한 요구사항, 기능 및 인공지능적 로봇을 연구하기 위하여 수상에서 바람, 파도 및 물살의 환경 적응을 위하여 쿼드로터를 활용한 자세제어 알고리즘을 제안한다. 그리고 로봇의 자율주행 및 충돌 회피를 위하여 VFF(Virtual Force Field) 알고리즘을 더욱더 확장한 EVFF(Expansion Virtual Force Field)를 사용하여 로봇과 장애물 사이에는 같은 극성의 전하를 가진다고 가정하고 로봇과 목표점 사이에 흡인력이 작용하며 로봇과 장애물 사이에는 반발력이 작용하여 원하는 목표점에 도달한다. 또한 기본적인 항로 유지뿐만 아니라 수상 로봇이 자율 항해를 하는 동안 직면하게 되는 고정, 이동 장애물에 대한 다양한 충돌 회피 상황들을 표현하기 위해서 파라메타들을 퍼지로 구성하였다. A key point of mobile robot is the technology to build a map of the environment and to localize itself using a map. Moreover sensor fusion technique is essential to reduce error rate for environment mapping information. Using these technologies, there many robots (housing robot, security robot, industrial robot) were developed by companies and research centers. Nowadays people are worried about disaster by environmental pollution. Therefore robot that has autonomous driving and monitoring environment to check pollution in real time has being important issue. Recently, according to improving remote control and communication techniques, mobile robots are efficiently used to work on the water. One of these robots, autonomous driving on the water with posture control system robot gathers information and transmits data to destination point as it moves across the river, water-storage and sea. This robot has mobility, environment acceptance, communication tool, information gathering process, saving energy technologies. As view more detail these technologies, robot used autonomous navigation, perception, self-localization, obstacle avoiding, posture control, efficient battery, and artificial intelligent process. All of these technologies are used in making monitoring robot which works on water environment. In this study, I suggest quad-rotor algorithm for robot on the water environment perception. And using extended virtual force field algorithm for autonomous navigation, obstacle avoiding. If we assume there are same polar with obstacle and robot, repulsive force() are engaged between robot and obstacle then absorption force() are engaged between robot and target point. Robot safely reaches the target point with two forces. Also I made parameters with fuzzy to represent crush avoiding saturations for fixed or non-fixed obstacles while mobile robot has autonomous driving on the water.

Affordable Water Quality Analysis: A Proposed Framework for The Development and Regulation of Low-Cost Water Quality Monitoring Devices

Kelley, Christopher Daniel ProQuest Dissertations & Theses The Johns Hopkins 2018 해외박사(DDOD)

Access to adequate supplies of potable water is a key driver of human health. Physical and chemical treatment processes are frequently necessary to make water safe to drink. Monitoring of water before, during, and after treatment is an essential component of the provision of potable water, and most aspects of water quality monitoring require electronic devices to augment human senses. Every nation sets rules governing the treatment and monitoring of drinking water, in an attempt to continuously ensure potability of drinking water supplies. Presently, however, the regulations governing the design of common electronic devices for water quality monitoring are developed and published by just two organizations – the US Environmental Protection Agency (EPA) and the International Organization for Standardization (ISO). The implications of this regulatory situation on drinking water quality monitoring, particularly in low-resource settings, are largely (perhaps completely) unaddressed in existing literature.Turbidity, which may be summarized as cloudiness in a body of liquid due to the scattering of light by particles suspended in that body, is internationally recognized as a simple and useful monitoring parameter for drinking water treatment. Using turbidity as an exemplar, this dissertation examines the structure of regulations governing the design of water quality monitoring devices, and the potential impact that regulatory structure has on the design, fabrication, and marketing of water quality monitoring devices, including both closed-source and open-source technology. National turbidity monitoring requirements for several nations, and the turbidity guidelines promulgated by the World Health Organization, are compared. The EPA and ISO turbidimeter regulations are also examined in relation to these national and international turbidity monitoring requirements. Design variables and requirements are identified which are generally necessary to ensure a properly functioning turbidimeter, but which are not explicitly stated in EPA and ISO turbidimeter regulations. Aspects of the commercial turbidimeter market, and EPA and ISO turbidimeter regulations, which are likely burdensome for water quality monitoring efforts in low-resource settings (such as rural communities in developing countries), are explored – perhaps chief among these being cost. While production of open-source turbidimeter designs provides a potential solution for turbidity monitoring in low-resource settings, open-source turbidimeter design efforts are currently far from able to meet global needs.To provide supplementary regulatory requirements for EPA and ISO turbidimeter standards, and to spur the development of market-ready open-source turbidimeter designs, a framework titled the Affordable Water Quality Analysis (AWQUA) device development is proposed. It consists of a turbidity-specific regulatory section, and a general water quality monitoring device development guidance section. Proper use of this guidance section is intended to strengthen open-source water quality monitoring device development efforts and encourage the production of device documentation suitable to demonstrate compliance with the regulatory section.An important contribution of this dissertation effort is the development and detailed description of four different examples of novel, low-cost, open-source water quality monitoring devices that motivated the proposed supplementary framework, informed its design, and serve to illustrate its application. First, a low-cost, open-source handheld turbidimeter based on a simple digital light detection sensor is detailed and discussed. The design, fabrication, and testing of this device served as a motivator for the development of the proposed supplementary turbidimeter development guidelines proposed. The turbidimeter nearly meets international regulatory guidelines, was fully described in a peer-reviewed publication, and is believed to be the most detailed open-source design of a digital turbidimeter publicly available (at the time of this writing) and yet contains several subtle but critical design flaws that are unaddressed in current national and international turbidimeter regulations. This prototype thus motivated and informed the design of the proposed new regulatory framework. Subsequently, three other promising open-source water quality monitoring designs were developed, fabricated, and evaluated under the AWQUA Framework: (1) a second low-cost open-source handheld turbidimeter, based on a highly precise light-to-voltage analog sensing setup; (2) a highly compact low-cost open-source inline turbidimeter, designed for continuous immersive monitoring of turbidity in surface waters; and (3) a low-cost open-source jar tester – a device used to evaluate certain physical and chemical treatments employed in drinking water treatment to reduce turbidity. These designs and the associated framework that grew from them are contributions toward the provision of “Affordable Water Quality Analysis” (AWQUA) capabilities for communities in low-resource settings.

Development of Electromagnetic-Triboelectric Hybrid Self-Charging Power Sources and Self-Powered Sensing Platforms for Multifunctional Smart IoT Applications

트릴로찬 광운대학교 일반대학원 2023 국내박사

IoT has played a significant role in the advancement of multiple domains where millions of sensors and devices are interconnected. Among these domains, autonomous systems (such as robotics, drones, underwater vehicles, humanoids, autonomous vehicles), smart homes or buildings, sports/gaming, healthcare monitoring, industrial automation, and outdoor environment monitoring platforms (such as air quality, water quality) are directly linked with the life of living creatures. At the same time, wireless monitoring technologies are prevailing over traditional wired interconnections. In the era of Artificial Intelligence, human-machine interfaces, and environmental monitoring concerns, a huge number of sensors and components are being deployed. The seamless operation of multiple sensors and components requires self-sustainable power supplies which may not be feasible to provide through conventional grid lines and rechargeable batteries due to installation, charging, and replacement complexities. Moreover, the integrated passive sensors increase the overall power consumption of the system thereby threatening the integrity of the monitoring systems. Over the years, alternative energy transduction strategies are being researched and deployed such as photovoltaic cells, wind turbines, battery backups, and nuclear power plants. However, the interconnection compatibility of these resources to the distributed sensors is challenging and a complex thing. Moreover, these efforts are less effective in terms of portability, miniaturization, cost-effectiveness, and undisrupted energy outputs. The vibration motion-based energy harvesting strategies based on electromagnetic, triboelectric, piezoelectric, and electrostatic, along with the hybridization with photovoltaic and wind energies could pave the sustainable path for modern and future smart IoT platforms. Parallelly these energy transduction methods are equally suitable to utilize as a self-powered sensor that can convert physical and or mechanical parameters into electrical signals directly thereby reducing the overall power consumption during signal processing for practical implementations. Therefore, mechanical vibration energy harvesters and self-powered sensors are the recently emerged alternatives to conventional power sources and passive sensing components. However, the random low-frequency nature of vibration, resonant behavior of harvesting components, a limited degree of freedom, and limited electron affinity of the triboelectric materials have constrained their practical implementation as an efficient power source and as a highly sensitive self-powered sensor on a large scale. To overcome these issues numerous novel strategies and designs have been investigated and implemented to develop efficacious electromagnetic, triboelectric, and hybrid energy harvesters and highly sensitive self-powered sensors for self-sustainable multifunctional smart IoT applications including multiple domains such as human body motion, human-machine interactions, automotive vibration, smart lighting control, user authentications systems, robotic, water wave monitoring systems and water quality monitoring systems, respectively. In the beginning, extensive research was carried out to generate the concept of battery-autonomous self-powered sensors and sensing systems. To realize this concept magnetic repulsion mechanisms and their usability in low-frequency random direction kinetic energy harvesting and self-powered motion sensing were investigated. Therefore, a magnetic repulsion-based battery-less arbitrary motion sensing system was designed and developed based on electromagnetic and triboelectric principles and demonstrated as a self-sustained motion sensing system with energy harvesting and self-powered sensing functionality together for wireless autonomous control applications. In this design, the magnetic repulsion strategy was utilized to detect in-plane random motion parameters such as motion direction, frequency, acceleration, tilting angle, and rotational speed. The generated energy (EMG: 27 mW, TENG: 56 µW) was utilized to charge the capacitor to operate signal processing and wireless transmission components for making the entire motion monitoring system self-powered. A custom-designed mobile application was utilized for real-time monitoring and display of the motion parameters wirelessly. To further boost the motion sensitivity, and output power, and to reduce design complexity within miniaturized volume, an interdigitated electrode pattern was optimized for TENG in the second work. Where, nanowire and nano-grass structures were developed through surface modification over polytetrafluorethylene (PTFE) and Aluminum surface to maximize the contact area and triboelectric performance, whereas a double-layered ferromagnetic composite of PDMS-FeSiCr/PDMS was introduced as a self-actuating layer of TENG to reduce the operational complexity. The optimized design includes magnets assisted dual mode (contact and sliding) triboelectric sensors and an integrated high-performance electromagnetic generator as a self-sustained system for the robotic balancing platform with enhanced motion sensitivity. The motion parameters such as direction, frequency, acceleration, angle, and rotation degrees were detected from the single platform. Furthermore, the practical demonstration was realized by utilizing a developed self-powered motion sensing system to wirelessly control the custom-developed robotic ball balancing table. In the third work, a novel 2D MXene/PVDF nanofiber and nanofibrous mats were introduced as a highly electronegative triboelectric composite material with optimized concentration and thickness that significantly improved the TENG performance as a power source as well as a self-powered sensor owing to significant improvement in the dielectric property, charge density, and the current density. The developed TENG using MXene/PVDF composite nanofiber paired with nylon nanofiber was able to operate wearable sports watches and thermohydrometer sensors easily and was effective for self-powered step light control applications based on the human motion over the stairs. In the fourth work, a novel composite of 2D Siloxene/PVDF was introduced as a highly negative layer of TENG in the form of an electrospun nanofibrous mat. The facile fabricated nanofiber paired with nylon nanofiber significantly improved the triboelectric performance and was able to operate commercial low-power electronics. Furthermore, the excellent compressibility of the developed nanofiber showed great potential to use as a self-powered pressure sensor. Considering this aspect, a hybrid capacitive-triboelectric self-powered static and dynamic pressure sensor was developed that showed promising applications for measuring static and dynamic pressure simultaneously without requiring external power. In this case, the hybrid pressure sensor array was designed and demonstrated as a self-powered user authentication system powered by Artificial Intelligence that can accurately identify the user during pressing a keypad considering the pressure parameters and user behaviors into account with excellent accuracy. In the fifth work, the developed MXene/PVDF nanofiber was utilized as a self-powered water wave motion sensor by integrating it with a novel ellipsoidal-shaped arbitrary direction water wave energy harvester in which the six pairs of electromagnetic nanogenerators and four pairs of triboelectric motion sensors were integrated for simultaneous energy generation and water wave motion parameter sensing without requiring external electricity and the wave parameters (wave height, wave period, wave length and wave frequency) were wirelessly monitored on custom-designed mobile application through the free-floating hybrid ellipsoidal device. The triboelectric generators were actuated with the help of magnetic ferromagnetic film, the attraction between the FeSiCr film, and the working magnet for EMG. In the sixth work, the water wave monitoring system was further optimized, and a novel Brachistochrone bowl-shaped geometry was introduced that offered the fastest descent for the magnet motion inside the curve thus maximizing the energy output along a random path. In addition to the integrated triboelectric motion sensors as in previous work, a multifunctional physio-electrochemical (wave motion, temperature, pH, Chloride ion, and water conductivity) sensing unit was designed, developed, and integrated with the brachistochrone bowl to realize a freely floating self-powered wireless autonomous smart pool monitoring system powered by the inbuilt electromagnetic energy harvester. A custom-developed smart pool monitoring mobile application was developed to wirelessly monitor the various contents of the pool water for maintaining a safe and hygienic swimming environment.

Development of implementation methods of water quality trading policy : using hydrological simulation program-fortran (HSPF)

신이숙 UMI Dissertation Services 2011 국내박사

한강수계의 주요지점 수질현황 및 환경오염물질에 관한 연구

이재준 연세대학교 보건환경대학원 2005 국내석사

The Han River is taking an important role as a water supply source to the residents of Seoul Metropolitan area as well as a water source for the agricultural and industrial use. However, recent industrialization and urbanization of the basin of the Han River made the industry and the surrounding area crowded, which have caused complicated and diversified environmental pollution sources. The purpose of this study is to understand the present situation of the water quality and the variation patterns through the water quality analysis of the Han River watersheds'' pollutants in order to suggest the future direction of water quality management hereafter. 14 years'' of data set from the Ministry of Environment from January, 1989 to 2003 were analyzed to study the characteristics of water quality changes at the major Han River watersheds, Uiam-dam, Chungju-dam, Paldang-dam, Noryangjin, and Gayang. Analysis was focused to find the correlation between the environmental pollution materials. There was a significant difference in the concentration of pollutants between the upper and down stream. The concentrations at the down stream points was decreasing mainly due to the precipitation. The result from the correlation analysis showed that BOD and COD had a strong positive correlation with a correlation coefficient of 0.945 while the water temperature and DO had a negative correlation with a correlation coefficient of -0.564. The other pollution materials also had significant correlations particularly on COD, T-N and T-P categories. This suggested that COD, T-N and T-P categories should be included in addition to BOD in establishing indices. The data set used for conducting water quality and the correlation analysis were collected by once-a-month measurement, thus, the number of data was not enough to presume the causes of the changes. There should be a more discussion about a system that can reconfirm the measured water quality data to construct the scientific water quality monitoring operation system and reliable data system both for flood and dry seasons in establishing the water quality conservation policy. 한강은 현재 수도권 시민의 상수원인 동시에 농업용 및 공업용의 수자원으로서 중요한 역할을 하고 있다. 그러나 최근 한강 유역의 공업화와 도시화로 산업 및 주변 환경이 복잡하고 이로 인한 환경오염 요인 또한 복잡․다변화되고 있는 실정이다. 이에 한강수계 오염물질의 수질분석을 통하여 현재 수질상태를 정확히 이해하고 변화요인을 추정하여 향후 수질관리 방향을 제시하고자 하였다. 본 연구에서는 1989년 1월부터 2003년 까지 14년간의 환경부 자료를 이용하여 한강수계의 주요지점인 의암댐, 충주댐, 팔당댐, 노량진, 가양의 수질변화 특성을 조사하고 환경 오염물질 간에 상관성을 분석하여 다음과 같은 결과를 얻었다. 한강 수계 내 오염물질은 상, 하류 간 농도차이가 뚜렷하고 강수의 영향으로 하류지점의 농도가 감소되는 현상이 나타났다. 또한 상관성 분석 결과 BOD와 COD 상관관계는 0.945의 높은 정상관, 수온과 DO는 -0.564로 역상관을 나타냈으며 다른 오염물질간 상관관계도 COD, T-N, T-P 항목을 중심으로 유의한 상관성을 나타냈다. 이상을 살펴볼 때, 수질의 지표설정에 있어 BOD외에 COD, T-N, T-P 항목을 병행하여 판단되어야 할 것으로 사료된다. 수질분석과 상관성분석을 수행함에 있어 측정 자료는 환경부 수질측정망상의 관측지점에서 월 1회 관측되어 수집된 자료로, 변화요인을 추정하기에는 극히 제한된 점이 있음을 알 수 있었다. 수질보전정책 수립에 있어 홍수기와 갈수기의 적절한 과학적인 수질측정망 운영 설계 및 신뢰성 있는 자료 구축을 위해 측정된 수질자료를 재확인하는 시스템이 논의 되어져야 할 것이다.

Designing an optimal monitoring network for water quality in the estuary

김남훈 서울대학교 대학원 2019 국내박사

연안의 물리 및 환경 특성은 조석, 파랑, 담수 배출 등과 같이 다양한 요인에 의해 변화한다. 특히, 금강 하구는 강우에 의한 하구둑 내부 수위의 변화로 인위적인 담수 방류가 이루어지기 때문에 해수와 담수가 서로 혼합되어 담수 영향역의 변화가 매우 큰 해역이다. 이러한 담수 영향역의 변화는 연안의 물리 및 환경 변화에 영향을 미칠 수 있어, 이를 효과적으로 관리하기 위한 모니터링이 수행되어야 한다. 모니터링에는 크게 두 가지 방법이 있는데, 첫째는 현장에서 직접 주기적으로 데이터를 수집하는 정기 현장 관측이다. 다른 하나는, 고정된 지점에 관측소를 설치하여 실시간으로 연속된 자료를 수집하는 실시간 모니터링이다. 일반적으로 정기 현장 관측의 정점은 연구자의 경험에 의존하여 결정되어 왔으며, 실시간 관측소는 접근성을 우선으로 고려하여 육지에 근접한 곳에 설치 및 운영되어 왔다. 문제는 해역의 특성을 효과적으로 반영하고 관리하기 위한 모니터링 정점의 개수와 위치 등을 결정할 수 있는 방법론이 아직 제안된 바가 없다는 점이다. 본 연구에서는 금강하구역을 대상으로 모의된 수치 모델(Delft-3D) 자료를 이용하여 해역의 시·공간적 특성을 효과적으로 반영할 수 있는 현장 관측 및 실시간 모니터링 설계 전략을 제시하였다. EOF 분석은 해역의 시공간적 특성을 나타낼 수 있는 설계 변수를 결정하기 위해 수행하였다. 설계 변수의 시·공간적 특성 변화를 재구성하기 위해서 공간 분포를 연속적으로 구성할 수 있는 객관 분석의 보간 함수를 목적 함수로 구축하고, 이를 특정 설계 영역 안으로 구속시켜 도식적으로 국소 혹은 전역 최소 및 최대치를 도출 해 내었다. 이렇게 재구성된 최적점의 배열을 이용하여 공간 분포를 재구성하고, 이를 참값과 비교하여 적정성 여부를 평가하였다. 또한, 본 연구에서 제안하는 방법론적 접근법으로 취득한 최적점을 종래의 방법으로 결정된 지점과 비교 분석을 수행하였다. 도식적으로 선정 된 정점들로 재구성한 공간 분포는 기존 연구의 방법론을 적용하여 취득한 정점들의 배열보다 공간 분포의 재구성에 더 우수한 성능을 가지고 있음을 확인하였다. 또한, 실시간 관측소는 전역적인 시계열 변동성(계절 변동성) 및 지역적인 시계열 변동성(담수 방류)의 자료 획득이 가능한 특정 영역을 제언하였다. 이러한 방법론적 설계 기법의 개발 및 적용은 보다 공학적이고 합리적인 위치에서의 관측망 구성이 가능함을 시사하였다. The physical and environmental characteristics of an estuarine area can be affected by various factors such as tide, wave, and freshwater discharge, etc. In particular, Geumgang Estuary (GE) is artificially discharging the freshwater according to the change of water level in the reservoir due to the increase of rainfall, so that the seawater and freshwater are mixed with each other and the change of the freshwater influence area is substantial. Therefore, the physical and environmental changes of an estuarine area may occur, and appropriate monitoring should be carried out to manage them effectively. There are two kinds of the monitoring method. One is periodic on-site field observation which acquired data on the field, and the other is real-time monitoring which obtained the continuous data from the fixed station. In general, the locations of the on-site field observation were set up to cover the whole target area depending on the researchers’ common experience. In addition, real-time monitoring stations were installed close to the land just only considering its accessibility. The problem is that there is no standard framework to determine the number and location of the monitoring points for the purpose of effectively representing and managing the characteristics of an estuarine area. In this study, we propose an optimal design strategy of the on-site field observation and real-time monitoring that can represent the spatial and temporal variability of the freshwater using the numerical model (Delft-3D) data in the GE. The EOF analysis is performed to determine the design variables which can represent the spatial and temporal characteristics. In order to reconstruct the temporal and spatial characteristics of the design variables, an interpolation function of the objective analysis that can construct the continuous spatial distribution is used as an objective function. The constrained optimization method constraining the objective function into the feasible region is graphically applied to find the local or global minimum and maximum solutions. The spatial distribution is reconstructed by using the selected solutions and compared it with the true distribution to evaluate its reconstruction capacity. In addition, the validation of the selected points determined by the present framework is performed by comparing with the points determined by the conventional method. The spatial distribution of the graphically selected points has better performance than the points selected by the conventional optimization methods with the same number of monitoring points. Moreover, the real-time monitoring station can be installed to the specific regions to acquire the global signals (i.e., seasonal variation) and local signals (i.e., freshwater discharge). As a result, the monitoring network of water quality in the estuary can be optimally designed by using the well-organized framework proposed in this study.

Optimization of paths and locations of water quality monitoring systems in surface water environments

Nam, Kijin UMI Dissertation Services 2008 국내박사