• Title/Summary/Keyword: Key Performance Parameter

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Seismic Behavior of Inverted T-type Wall under Earthquake Part II : Effect of Input Earthquake Motion (역T형 옹벽의 지진시 거동특성 Part II : 입력 지진파의 영향)

  • Lee, Jin-sun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.20 no.1
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    • pp.9-19
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    • 2016
  • Permanent deformation plays a key role in performance based earthquake resistant design. In order to estimate permanent deformation after earthquake, it is essential to secure reliable response history analysis(RHA) as well as earthquake scenario. This study focuses on permanent deformation of an inverted T-type wall under earthquake. The study is composed of two separate parts. The first one is on the verification of RHA and the second one is on an effect of input earthquake motion. The former is discussed in companion paper and the latter in this paper. In order to investigate the effect of an input earthquake motion on the permanent deformation, three bins of spectral matched real earthquake records with different magnitude, regions, epicentral distance are constructed. Parametric study was performed using the verified RHA through the companion paper for each earthquake records in the bins. The most influential parameter affecting permanent displacement is magnitude. The other parameters describing earthquake motion are not significant enough to increase permanent displacement of the inverted T-type wall except for energy related parameters(AI, CI, SEI).

Meta learning-based open-set identification system for specific emitter identification in non-cooperative scenarios

  • Xie, Cunxiang;Zhang, Limin;Zhong, Zhaogen
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.16 no.5
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    • pp.1755-1777
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    • 2022
  • The development of wireless communication technology has led to the underutilization of radio spectra. To address this limitation, an intelligent cognitive radio network was developed. Specific emitter identification (SEI) is a key technology in this network. However, in realistic non-cooperative scenarios, the system may detect signal classes beyond those in the training database, and only a few labeled signal samples are available for network training, both of which deteriorate identification performance. To overcome these challenges, a meta-learning-based open-set identification system is proposed for SEI. First, the received signals were pre-processed using bi-spectral analysis and a Radon transform to obtain signal representation vectors, which were then fed into an open-set SEI network. This network consisted of a deep feature extractor and an intrinsic feature memorizer that can detect signals of unknown classes and classify signals of different known classes. The training loss functions and the procedures of the open-set SEI network were then designed for parameter optimization. Considering the few-shot problems of open-set SEI, meta-training loss functions and meta-training procedures that require only a few labeled signal samples were further developed for open-set SEI network training. The experimental results demonstrate that this approach outperforms other state-of-the-art SEI methods in open-set scenarios. In addition, excellent open-set SEI performance was achieved using at least 50 training signal samples, and effective operation in low signal-to-noise ratio (SNR) environments was demonstrated.

Effect of Interconnect Structure on the Cell Performance in Anode-supported Tubular SOFC Using Three-dimensional Simulation (3차원 수치모사를 통한 연료극 지지식 관형 고체산화물 연료전지의 전지 성능에 대한 연결재 구조 효과)

  • Hwang, Ji-Won;Lee, Jeong-Yong;Jo, Dong-Hyun;Jung, Hyun-Wook;Kim, Sung-Hyun
    • Clean Technology
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    • v.16 no.4
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    • pp.297-303
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    • 2010
  • Effect of interconnect structure on the cell performance in anode-supported tubular solid oxide fuel cell (SOFC) has been investigated in this study, employing the Fluent CFD solver. For the robust and reliable theoretical analysis corroborating experimental results, it is of great importance to elucidate the role of interconnect which is electrically connected with electrodes on the cell characteristics. From the fact that the thin interconnect provides the enhanced cell performance, it is revealed that the interconnect thickness is a key parameter that is able to effectively control the ohmic resistance. Under the constant thickness condition, the cell performance does not considerably change with the variation of interconnect width. This is because the current passage along with circumferential direction is not effectively altered by the change of interconnect width in tubular SOFC system.

Development of the Korean Practice Parameter for Adult Attention-Deficit/Hyperactivity Disorder

  • Bahn, Geon Ho;Lee, Young Sik;Yoo, Hanik K.;Kim, Eui-Jung;Park, Subin;Han, Doug Hyun;Hong, Minha;Kim, Bongseog;Lee, Soyoung Irene;Bhang, Soo Young;Lee, Seung Yup;Hong, Jin Pyo;Joung, Yoo-Sook
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.31 no.1
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    • pp.5-25
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    • 2020
  • Objectives: Adult attention-deficit/hyperactivity disorder (ADHD) is an important mental health problem that needs resolution, especially considering the high rates of ADHD continuation from childhood to adolescence/adulthood and the high prevalence of ADHD in adults. Adults with ADHD have lifelong negative impacts and require close monitoring with long-term follow-up. Hence, the establishment of a Korean practice parameter for adult ADHD is necessary to minimize discontinuation of treatment and enable information sharing among Korean mental health professionals. Methods: The Korean practice parameter was developed using an evidence-based approach consisting of expert consensus survey coupled with literature review. Results: According to the expert consensus survey, the most commonly used diagnostic methods were clinical psychiatric interview (20.66%) and self-report scales (19.25%) followed by attention (14.71%) and psychological tests (14.24%). Key evaluation instruments currently available in Korea are the World Health Organization Adult ADHD Self-Report Rating Scale, Korean Adult ADHD Rating Scale, Diagnostic Interview for ADHD in Adults, Barkley Deficits in Executive Functioning Scale for adults, Comprehensive Attention Test, Conners' Continuous Performance Test, and the subtests of Wechsler Adult Intelligence Scale, Digit Span and Letter-Number Sequencing. Although pharmacotherapy is recommended as the first-line of treatment for adult ADHD, we recommend that it be followed by a multimodal and multidisciplinary approach including psychoeducation, pharmacotherapy, cognitive behavior therapy and coaching. Conclusion: The Korean practice parameter introduces not only general information for the diagnosis and treatment of adult ADHD on a global scale, but also the process of diagnosis and treatment options tailored to the Korean population.

Study on Power Distribution Algorithm in terms of Fuel Equivalent (등가 연료 관점에서의 동력 분배 알고리즘에 대한 연구)

  • Kim, Gyoungeun;Kim, Byeongwoo
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • v.5 no.6
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    • pp.583-591
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    • 2015
  • In order to evaluate the performance of TAS applied to the hybrid vehicle of the soft belt driven, acceleration performance and fuel consumption performance is to be superior to the existing vehicle. The key components of belt driven TAS(Torque Assist System), such as the engine, the motor and the battery, The key components of the driven belt TAS, such as the engine, the motor, and the battery, have a significant impact on fuel consumption performance of the vehicle. Therefore, in order to improve the efficiency at the point of view based on the overall system, the study of the power distribution algorithm for controlling the main source powers is necessary. In this paper, we propose the power distribution algorithm, applied the homogeneous analysis method in terms of fuel equivalent, for minimizing the fuel consumption. We have confirmed that the proposed algorithm is contribute to improving the fuel consumption performance satisfied the constraints considering the vehicle status information and the required power through the control parameters to minimize the fuel consumption of the engine. The optimization process of the proposed driving strategy can reduce the trial and error in the research and development process and monitor the characteristics of the control parameter quickly and accurately. Therefore, it can be utilized as a way to derive the operational strategy to minimize the fuel consumption.

Analysis of the effect of blade positions on the aerodynamic performances of wind turbine tower-blade system in halt states

  • Ke, Shitang;Yu, Wei;Wang, Tongguang;Ge, Yaojun;Tamura, Yukio
    • Wind and Structures
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    • v.24 no.3
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    • pp.205-221
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    • 2017
  • The unsteady flow field disturbance between the blades and tower is one of the primary factors affecting the aerodynamic performance of wind turbine. Based on the research object of a 3MW horizontal axis wind turbine which was developed independently by Nanjing University of Aeronautics and Astronautics, numerical simulation on the aerodynamic performance of wind turbine system in halt state with blades in different position was conducted using large eddy simulation (LES) method. Based on the 3D unsteady numerical simulation results in a total of eight conditions (determined by the relative position with the tower during the complete rotation process of the blade), the characteristics of wind pressure distributions of the wind turbine system and action mechanism of surrounding flow field were analysed. The effect of different position of blades on the aerodynamic performance of wind turbine in halt state as well as the disturbance effect was evaluated. Results of the study showed that the halt position of blades had significant effect on the wind pressure distribution of the wind turbine system as well as the characteristics of flow around. Relevant conclusions from this study provided reference for the wind-resistant design of large scale wind turbine system in different halt states.

Effects of Hydro-Climate Conditions on Calibrating Conceptual Hydrologic Partitioning Model (개념적 수문분할모형의 보정에 미치는 수문기후학적 조건의 영향)

  • Choi, Jeonghyeon;Seo, Jiyu;Won, Jeongeun;Lee, Okjeong;Kim, Sangdan
    • Journal of Korean Society on Water Environment
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    • v.36 no.6
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    • pp.568-580
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    • 2020
  • Calibrating a conceptual hydrologic model necessitates selection of a calibration period that produces the most reliable prediction. This often must be chosen randomly, however, since there is no objective guidance. Observation plays the most important role in the calibration or uncertainty evaluation of hydrologic models, in which the key factors are the length of the data and the hydro-climate conditions in which they were collected. In this study, we investigated the effect of the calibration period selected on the predictive performance and uncertainty of a model. After classifying the inflows of the Hapcheon Dam from 1991 to 2019 into four hydro-climate conditions (dry, wet, normal, and mixed), a conceptual hydrologic partitioning model was calibrated using data from the same hydro-climate condition. Then, predictive performance and post-parameter statistics were analyzed during the verification period under various hydro-climate conditions. The results of the study were as follows: 1) Hydro-climate conditions during the calibration period have a significant effect on model performance and uncertainty, 2) calibration of a hydrologic model using data in dry hydro-climate conditions is most advantageous in securing model performance for arbitrary hydro-climate conditions, and 3) the dry calibration can lead to more reliable model results.

The Effectiveness of Sensory Integrative Intervention: A Systematic Review (감각통합중재 효과에 관한 체계적 고찰)

  • Kim, Kyeong-Mi
    • The Journal of Korean Academy of Sensory Integration
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    • v.7 no.2
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    • pp.77-90
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    • 2009
  • Objective : The purpose of this study was to provide evidence for the effectiveness of Sensory Integrative Intervention (SII) through a systematic review. Method : The systematic review was executed using MEDLINE/PubMed, PsycINFO, CINAHL, Cochrane Library, OTSeeker. The key words for search was "effects of sensory integration", "sensory integration therapy", and "sensory integration intervention". 11 studies were used for data analysis, and the level of evidence were level I, leve lII and level IV. The substances of review were subject (population), method (intervention type), effect of the intervention, outcome parameter, and outcome measurement. Results : 1. The subjects of SII were autism spectrum disorders (30.7%), pervasive developmental disorder (15.4%) and preterm infants (15.4%). 2. Most frequently used method was the traditional intervention of J. Ayres (36.5%). The outcome parameters of SII were behavioral outcome (40.63%), motor performance outcome (28.13%), sensory-based outcome (25.0%), and academic outcome (6.35%). 3. The effects of SII were improvement of motor performance (66.7%), sensory-based (62.5%), and behavior problems (61.5%). In most studies, however, academic skill such as writing skill was not a positive outcome parameter in terms of effectiveness of SII. Conclusions : The results implied that the sensory integrative intervention is effective on motor performance, sensory-based and behavioral change, but not on the academic skill. It is suggested that the future research need to be done to examine whether and how the effect of sensory integration intervention can be long-lasting and contribute any academic skill and activities of daily living performance.

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Analytical Study of Shear Capacity of Trapezoidal Corrugated Web Girders (건축물 적용을 위한 제형 절곡 웨브 보의 전단성능에 관한 해석적 연구)

  • Lee, Seo Haeng;Park, Geun Woo;Yoo, Jung Han
    • Journal of Korean Society of Steel Construction
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    • v.30 no.1
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    • pp.49-58
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    • 2018
  • This study conducted nonlinear finite element analysis to figure out the influence of shear performance on the ${\beta}$ of girders with trapezoidal corrugated web. Through the experiment specimen, analysis model which is highly accurate was verified. Based on this, a parameter analysis was conducted on key variables affecting ${\beta}$. Proposed formulas of previous studies were analyzed using parameter analysis result. Eurocode was designed to be safer than other proposals. Only models that are included in the inelastic area, depending on the Moon's proposal, were satisfied the proposed formulas by Kim to enhance economic design.

Identification of Fuzzy Inference Systems Using a Multi-objective Space Search Algorithm and Information Granulation

  • Huang, Wei;Oh, Sung-Kwun;Ding, Lixin;Kim, Hyun-Ki;Joo, Su-Chong
    • Journal of Electrical Engineering and Technology
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    • v.6 no.6
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    • pp.853-866
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    • 2011
  • We propose a multi-objective space search algorithm (MSSA) and introduce the identification of fuzzy inference systems based on the MSSA and information granulation (IG). The MSSA is a multi-objective optimization algorithm whose search method is associated with the analysis of the solution space. The multi-objective mechanism of MSSA is realized using a non-dominated sorting-based multi-objective strategy. In the identification of the fuzzy inference system, the MSSA is exploited to carry out parametric optimization of the fuzzy model and to achieve its structural optimization. The granulation of information is attained using the C-Means clustering algorithm. The overall optimization of fuzzy inference systems comes in the form of two identification mechanisms: structure identification (such as the number of input variables to be used, a specific subset of input variables, the number of membership functions, and the polynomial type) and parameter identification (viz. the apexes of membership function). The structure identification is developed by the MSSA and C-Means, whereas the parameter identification is realized via the MSSA and least squares method. The evaluation of the performance of the proposed model was conducted using three representative numerical examples such as gas furnace, NOx emission process data, and Mackey-Glass time series. The proposed model was also compared with the quality of some "conventional" fuzzy models encountered in the literature.