• 제목/요약/키워드: Dam process

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A Study on the Acceptance of Wearable Computers based on the Extended Technology Acceptance Model (확장된 혁신기술수용모델을 이용한 웨어러블 컴퓨터의 수용에 관한 연구)

  • Lee, Hyun-Mee
    • The Research Journal of the Costume Culture
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    • v.17 no.6
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    • pp.1155-1172
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    • 2009
  • Wearable computers can be defined as next generation clothing integrated with various digital functions and devices. Unlike existing computers, they are viewed as human-centric computers customized for information utilization and other specific human needs. This study is intended to discover how consumers are accepting wearable computers, which are different from existing computers, based on Technology Acceptance Model(TAM) and to extend the model by adding variable regarding acceptance of wearable computers. A total of 683 copies of questionnaires, distributed to those aged 19 and older, both male and female, were collected online. The data was statistically analyzed for this study using the extended TAM. In order to test hypotheses, the structural equation model using the Lisrel 8.30 version was performed. For analyzing constructs(or traits) of research model, exploratory factor was conducted and the measurement model was assessed from the result. Reliability was assessed through confirmatory factor analysis and the calculation of Cronbach's alpha coefficients. Overall, model fit was assessed by statistical indexes: Chi-square value, GFI, AGFI, and RMR. This study analyzed the process of acceptance of wearable computers with the extended TAM that includes a variable, perceived value, on the basis of previous studies. The results of the analysis revealed that attitude toward wearable computer was directly influenced by perceived usefulness and perceived value but indirectly influenced by perceived ease of use. Acceptance intention of the wearable computer was directly influenced by perceived value and attitude toward wearable computer. To be more specific, perceived usefulness was significantly correlated with both attitude toward wearable computer and acceptance intention of the wearable computer. Perceived value was also significantly correlated with both attitude toward wearable computer and acceptance intention of the wearable computer. The results of this study also suggested that perceived ease of use was actually a causal antecedent to perceived usefulness and perceived value. This research revealed that extended TAM to investigate the acceptance of wearable computer was appropriate. This study is intended to provide a theoretical framework for adoption of wearable computer and suggest empirical analysis that can serve as a guide for wearable computer.

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Development of ArcGIS-based Model to Estimate Monthly Potential Soil Loss (월단위 토양유실가능성 추정을 위한 ArcGIS 기반의 모형 개발)

  • Yu, Na Young;Lee, Dong June;Han, Jeong Ho;Lim, Kyoung Jae;Kim, Jonggun;Kim, Ki Hyoung;Kim, Soyeon;Kim, Eun Seok;Park, Youn Shik
    • Journal of The Korean Society of Agricultural Engineers
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    • v.59 no.1
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    • pp.21-30
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    • 2017
  • Soil erosion has been issued in many countries since it causes negative impacts on ecosystem at the receiving water bodies. Therefore best management practices to resolve the problem in a watershed have been developed and implemented. As a prior process, there is a need to define soil erosion level and to identify the area of concern regarding soil erosion so that the practices are effective as they are designed. Universal Soil Loss Equation (USLE) were developed to estimate potential soil erosion and many Geographic Information System (GIS) models employ USLE to estimate soil erosion. Sediment Assessment Tool for Effective Erosion Control (SATEEC) is one of the models, the model provided several opportunities to consider various watershed peculiarities such as breaking of slope length, monthly variation of rainfall, crop growth at agricultural fields, etc. SATEEC is useful to estimate soil erosion, however the model can be implemented with ArcView software that is no longer used or hard to use currently. Therefore SATEEC based on ArcView was rebuild for the ArcGIS software with all modules provided at the previous version. The rebuilt SATEEC, ArcSATEEC, was programmed in ArcPy and works as ArcGIS Toolset and allows considering monthly variations of rainfall and crop growth at any watershed in South-Korea. ArcSATEEC was applied in Daecheong-dam watershed in this study, monthly soil erosion was estimated with monthly rainfall and crop growth variation. Annual soil erosion was computed by summing monthly soil erosion and was compared to the conventional approach to estimate annual soil erosion. The annual soil erosion estimated by the conventional approach and by summing monthly approach did not display much differences, however, ArcSATEEC was capable to provide monthly variation of soil erosion.

Effects of Curing Temperature on the Optical and Charge Trap Properties of InP Quantum Dot Thin Films

  • Mohapatra, Priyaranjan;Dung, Mai Xuan;Choi, Jin-Kyu;Jeong, So-Hee;Jeong, Hyun-Dam
    • Bulletin of the Korean Chemical Society
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    • v.32 no.1
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    • pp.263-272
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    • 2011
  • Highly luminescent and monodisperse InP quantum dots (QDs) were prepared by a non-organometallic approach in a non-coordinating solvent. Fatty acids with well-defined chain lengths as the ligand, a non coordinating solvent, and a thorough degassing process are all important factors for the formation of high quality InP QDs. By varying the molar concentration of indium to ligand, QDs of different size were prepared and their absorption and emission behaviors studied. By spin-coating a colloidal solution of InP QD onto a silicon wafer, InP QD thin films were obtained. The thickness of the thin films cured at 60 and $200^{\circ}C$ were nearly identical (approximately 860 nm), whereas at $300^{\circ}C$, the thickness of the thin film was found to be 760 nm. Different contrast regions (A, B, C) were observed in the TEM images, which were found to be unreacted precursors, InP QDs, and indium-rich phases, respectively, through EDX analysis. The optical properties of the thin films were measured at three different curing temperatures (60, 200, $300^{\circ}C$), which showed a blue shift with an increase in temperature. It was proposed that this blue shift may be due to a decrease in the core diameter of the InP QD by oxidation, as confirmed by the XPS studies. Oxidation also passivates the QD surface by reducing the amount of P dangling bonds, thereby increasing luminescence intensity. The dielectric properties of the thin films were also investigated by capacitance-voltage (C-V) measurements in a metal-insulator-semiconductor (MIS) device. At 60 and $300^{\circ}C$, negative flat band shifts (${\Delta}V_{fb}$) were observed, which were explained by the presence of P dangling bonds on the InP QD surface. At $300^{\circ}C$, clockwise hysteresis was observed due to trapping and detrapping of positive charges on the thin film, which was explained by proposing the existence of deep energy levels due to the indium-rich phases.

Evaluation of Land Subsidence Risk Depending on Grain Size and Verification using Numerical Analysis (지반입도조건에 따른 지반함몰 가능성 평가 및 수치해석적 검증)

  • Lee, Jong-Hyun;Jin, Hyun-Sik;Baek, Yong;Yoon, Hyeong-Suk
    • The Journal of Engineering Geology
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    • v.27 no.2
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    • pp.133-141
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    • 2017
  • In this study, filter conditions by difference in grading between core material and filter material used for dam construction was applied as evaluation condition for surrounding ground conditions near excavation site in a bid to identify the risk of land subsidence resulting from the erosion of soil particles. To that end, filter conditions proposed for the test was evaluated and the risk of land subsidence depending on grain size conditions was also evaluated using the filter conditions developed by COE. Consequently, evaluation diagram that can be used to determine the risk of land subsidence using grain size conditions obtained from ground investigation data was developed, which is expected to help evaluate the possibility of land subsidence depending on changes to the stratum. To simulate the particle flow process, PFC3D program was used. It's not only intended to determine the land subsidence pattern caused by falling ground water level but also predict and evaluate the land subsidence caused by soil erosion using grain size condition which can be verified by numerical analysis approach.

Conceptual eco-hydrological model reflecting the interaction of climate-soil-vegetation-groundwater table in humid regions (습윤 지역의 기후-토양-식생-지하수위 상호작용을 반영한 개념적인 생태 수문 모형)

  • Choi, Jeonghyeon;Kim, Sangdan
    • Journal of Korea Water Resources Association
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    • v.54 no.9
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    • pp.681-692
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    • 2021
  • Vegetation processes have a significant impact on rainfall runoff processes through evapotranspiration control, but are rarely considered in the conceptual lumped hydrological model. This study evaluated the model performance of the Hapcheon Dam watershed by integrating the ecological module expressing the leaf area index data sensed remotely from the satellite into the hydrological partition module. The proposed eco-hydrological model has three main features to better represent the eco-hydrological process in humid regions. 1) The growth rate of vegetation is constrained by water shortage stress in the watershed. 2) The maximum growth of vegetation is limited by the energy of the watershed climate. 3) The interaction of vegetation and aquifers is reflected. The proposed model simultaneously simulates hydrologic components and vegetation dynamics of watershed scale. The following findings were found from the validation results using the model parameters estimated by the SCEM algorithm. 1) Estimating the parameters of the eco-hydrological model using the leaf area index and streamflow data can predict the streamflow with similar accuracy and robustness to the hydrological model without the ecological module. 2) Using the remotely sensed leaf area index without filtering as input data is not helpful in estimating streamflow. 3) The integrated eco-hydrological model can provide an excellent estimate of the seasonal variability of the leaf area index.

A Study on the Woodam Jeong Si-Han(愚潭 丁時翰)'s "Siqibianzheng (「四七辨證」)" (우담 정시한의 「사칠변증(四七辨證)」에 관한 연구)

  • Seo, Geun-Sik
    • The Journal of Korean Philosophical History
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    • no.59
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    • pp.343-370
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    • 2018
  • Jeong Si-Han(丁時翰) completed "Siqibianzheng"("四七辨證") at the age of 72, and later had the argument over Runwuxingtongyilunzheng(人物性同異論爭) with his disciple, Lee Sik(李?). Jeong Si-Han(丁時翰) had the position of Runwuxingyilun(人物性異論) and Lee Sik(李?) Runwuxingtonglun(人物性同論). Yet, the argument over Runwuxingtongyilunzheng(人物性同異論爭) had been forgotten and "Siqibianzheng"("四七辨證") could be acknowledged because Toegye school(退溪學派) and Yulgok school(栗谷學派) were conflicting and criticizing each other's stance at that time. It seems like Lee Hyeon-Il(李玄逸)'s "Liqulishilunsiduanqiqingshubian"("栗谷李氏論四端七情書辨") had a great influence on the completion of "Siqibianzheng" ("四七辨證"). Lee Yi(李珥)'s thought of Siduan(四端) and Qiqing(七情) was 'the position of Hunlun(渾淪)' that 'Qiqing(七情) includes Siduan(四端)', and Lee Hwang(李滉) had the 'position of Fenkai(分開)' that Siduan(四端) and Qiqing(七情) should be interpreted differently. Jeong Si-Han(丁時翰) criticized the stance of Hunlun(渾淪) from the position of Fenkai(分開). What did Jeong Si-Han(丁時翰) try to pursue through "Siqibianzheng"("四七辨證")? This fact tends to make us forget the controversy over Runwuxingtongyilunzheng(人物性同異論爭) between Jeong Si-Han(丁時翰) and disciple Lee Sik(李?). Now we know the fact that Jeong Si-Han(丁時翰) criticized Lee Yi(李珥) in "Siqibianzheng"("四七辨證"), but don't care much about the fact that Jeong Si-Han(丁時翰) caused the controversy over Runwuxingtongyilun(人物性同異論). Why "Siqibianzheng"("四七辨證") has remained in our memory even though it was an important one? It might be because "Siqibianzheng"("四七辨證") had an impact on Lee Sik(李?), Shin Hu-Dam(愼後聃), and even Jeong Yak-Yong(丁若鏞) in the process of summarizing the arguments over Siduanqiqinglunzheng(四端七情論爭) since Jeong Si-Han(丁時翰) regardless of whether Jeong Si-Han(丁時翰) had hoped it or not.

Application of land cover and soil information for improvement of HSPF modeling accuracy (HSPF 예측 정확도 제고를 위한 토지피복 및 토양 특성 자료의 활용)

  • Kang, Yooeun;Kim, Jaeyoung;Seo, Dongil
    • Journal of Korea Water Resources Association
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    • v.55 no.10
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    • pp.823-833
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    • 2022
  • This study aims to improve the runoff modeling accuracy of a basin using Hydrological Simulation Program-FORTRAN (HSPF) model by considering nonhomogeneous characteristics of a basin. By entering classified values according to the various types of land cover and soil to the parameters in HSPF-roughness coefficient (NSUR), infiltration (INFILT), and evapotranspiration (LZETP)- the heterogeneity of the Yongdam Dam basin was reflected in the model. The results were analyzed and compared with the one where the parameters were set as a single value throughout the basin. The flow rate and water quality simulation results showed improved results when classified parameters were used by land cover and soil type than when single values were used. The parameterization changed not only the flow rate, but also the composition ratio of each hydrologic components such as surface runoff, baseflow, and evapotranspiration, which shows the impact of the value set to a parameter on the entire hydrological process. This implies the importance of considering the heterogeneous characteristics of the land cover and soil of the basin when setting the parameters in a model.

Research on ANN based on Simulated Annealing in Parameter Optimization of Micro-scaled Flow Channels Electrochemical Machining (미세 유동채널의 전기화학적 가공 파라미터 최적화를 위한 어닐링 시뮬레이션에 근거한 인공 뉴럴 네트워크에 관한 연구)

  • Byung-Won Min
    • Journal of Internet of Things and Convergence
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    • v.9 no.3
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    • pp.93-98
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    • 2023
  • In this paper, an artificial neural network based on simulated annealing was constructed. The mapping relationship between the parameters of micro-scaled flow channels electrochemical machining and the channel shape was established by training the samples. The depth and width of micro-scaled flow channels electrochemical machining on stainless steel surface were predicted, and the flow channels experiment was carried out with pulse power supply in NaNO3 solution to verify the established network model. The results show that the depth and width of the channel predicted by the simulated annealing artificial neural network with "4-7-2" structure are very close to the experimental values, and the error is less than 5.3%. The predicted and experimental data show that the etching degree in the process of channels electrochemical machining is closely related to voltage and current density. When the voltage is less than 5V, a "small island" is formed in the channel; When the voltage is greater than 40V, the lateral etching of the channel is relatively large, and the "dam" between the channels disappears. When the voltage is 25V, the machining morphology of the channel is the best.

Effect of Different Curing Methods on the Unconfined Compressive Strength of Cemented Sand (양생방법에 따른 고결모래의 일축압축강도 특성)

  • Park, Sung-Sik;Kim, Ki-Young;Choi, Hyun-Seok;Kim, Chang-Woo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.5C
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    • pp.207-215
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    • 2009
  • Cemented soils or concrete are usually cured under moisture conditions and their strength increases with curing time. An insufficient supply of water to cemented soils can contribute to hydration process during curing, which results in the variation of bonding strength of cemented soils. In this study, by the consideration of in situ water supply conditions, cemented sand with cement ratio less than 20% is prepared by air dry, wrapped, moisture, and underwater conditions. A series of unconfined compression tests are carried out to evaluate the effect of curing conditions on the strength of cemented soils. The strength of air dry curing specimen is higher than those of moisture and wrapped cured specimens when cement ratio is less than 10%, whereas it is lower when cement ratio is greater than 10%. Regardless of cement ratio, air dry cured specimens are stronger than underwater cured specimens. A strength increase ratio with cement ratio is calculated based on the strength of 4% cemented specimen. The strength increase ratio of air dry cured specimen is lowest and that of wrapped, moisture, and underwater cured ones increased by square. Strength of air dry cured specimen drops to maximum 30% after wetting when cement ratio is low. However, regardless of cement ratio, strength of moisture and wrapped specimens drops to an average 10% after wetting. The results of this study can predict the strength variation of cemented sand depending on water supply conditions and wetting in the field, which can guarantee the safety of geotechnical structures such as dam.

Integrating Urban Planning and Environmental Impact Assessment for Enhancing Citizen Participation : Focusing on Official Development Assistance Project in Kenya (도시계획과 환경영향평가 제도의 통합적 접근을 통한 시민 참여 확대 방안: 케냐 ODA 사업 사례를 바탕으로)

  • Yeom, Jaeweon;Ha, Dongoh;Jung, Juchul
    • Journal of Environmental Impact Assessment
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    • v.29 no.5
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    • pp.338-349
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    • 2020
  • The importance of citizen participation, especially in urban planning, is increasing. Citizen participation is the sharing of control or influence on decisions and choices that affect stakeholders, and providing citizens with the opportunity to participate in the decision-making process. The paradigm of urban planning has also shifted from the rational planning model, which relied solely on the rationality of planners, to expand citizen participation. In fact, citizen participation in the process of establishing a vision for comprehensive plan is expanding, especially in metropolitan governments such as Seoul, Busan, and Daegu. However, there are criticisms that citizen cannot practically participate in urban planning due to limited participation methods and lack of participation in the pre-planning process. Accordingly, the necessity of institutionalization of citizen participation in the urban planning has been raised. According to literature reviews, foreign countries have integrated environmental impact assessment (EIA) into the urban planning to institutionalize citizen participation and pursue sustainability of the plan. In particular, the EIA actively includes citizen participation from the scoping stage to identify the issues. However, it was pointed out that there is a limitation to guaranteeing sustainability of the plan since EIA is carried out only at the urban project level. In other words, in order to expand citizen participation and ensure sustainability through the integrated approach, analysis of EIA in urban planning level is needed. Therefore, this study carried out a case study of EIA in the official development assistance of the Kenya multi-purpose dam construction to analyze the impact assessment in a wider scope than the urban project-level.