• Title/Summary/Keyword: two stage hybrid system

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Design Optimization of Single-Stage Launch Vehicle Using Hybrid Rocket Engine

  • Kanazaki, Masahiro;Ariyairt, Atthaphon;Yoda, Hideyuki;Ito, Kazuma;Chiba, Kazuhisa;Kitagawa, Koki;Shimada, Toru
    • International Journal of Aerospace System Engineering
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    • v.2 no.2
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    • pp.29-33
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    • 2015
  • The multidisciplinary design optimization (MDO) of a launch vehicle (LV) with a hybrid rocket engine (HRE) was carried out to investigate the ability of an HRE for a single-stage LV. The non-dominated sorting genetic algorithm-II (NSGA-II) was employed to solve two design problems. The design problems were formulated as two-objective cases involving maximization of the downrange distance over the target flight altitude and minimization of the gross weight, for two target altitudes: 50.0 km and 100.0 km. Each objective function was empirically estimated. Several non-dominated solutions were obtained using the NSGA-II for each design problem, and in each case, a trade-off was observed between the two objective functions. The results for the two design problem indicate that economical performance of the LV is limited with the HRE in terms of the maximum downrange distances achievable. The LV geometries determined from the non-dominated solutions were examined.

A Study on ESS Optimal Operation Strategy Using Two Stage Hybrid Optimization (Two Stage Hybrid Optimization을 사용한 ESS 최적 운전 전략에 대한 연구)

  • Gong, Eun-Kyoung;Sohn, Jin-Man
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.7
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    • pp.833-839
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    • 2018
  • This paper presents an analysis and the methodology of optimal operation strategy of the ESS(Energy Storage System) for reduce electricity charges. Electricity charges consist of a basic charge based on the contract capacity and energy charge according to the power usage. In order to use electrical energy at minimal charge, these two factors are required to be reduced at the same time. QP(Quadratic Programming) is appropriate for minimization of the basic charge and LP(Linear Programmin) is adequate to minimize the energy charge. However, the integer variable have to be introduced for modelling of different charge and discharge efficiency of ESS PCS(Power Conversion System), where MILP(Mixed Integer Linear Programming) can be used. In this case, the extent to which the peak load savings is accomplished should be assumed before the energy charge is minimized. So, to minimize the electricity charge exactly, optimization is sequentially performed in this paper, so-called the Two Stage Hybird optimization, where the extent to which the peak load savings is firstly accomplished through optimization of basic charge and then the optimization of energy charge is performed with different charge and discharge efficiency of ESS PCS. Finally, the proposed method is analyzed quantitatively with other optimization methods.

Time-Dependent Behavior of Waste-Air Treatment Using Integrated Hybrid System (통합 하이브리드시스템을 활용한 폐가스 처리 거동)

  • Lee, Eun Ju;Lim, Kwang-Hee
    • Korean Chemical Engineering Research
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    • v.60 no.1
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    • pp.100-115
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    • 2022
  • In this study, integrated hybrid system (IHS) composed of two alternatively-operating UV/photocatalytic reactor (AOPR) process and biofilter processes of a biofilter system having two units (i.e., Rup and Rdn) with an improved design (R reactor) and a conventional biofilter (L reactor) was constructed, and its transient behavior was observed to perform the successful treatment of waste air containing ethanol and hydrogen sulfide (H2S). At the IHS-operating stages of HA1, HA2 and HA3T of reversed feed direction, the AOPR process showed not only ethanol-removal efficiencies of 55, 50 and 45%, respectively, but also H2S-removal efficiencies of 70, 60 and 37%, respectively. In particular, a drastic decrease of H2S-removal efficiency at the stage of HA3T was observed due to a doubling of H2S-inlet concentration fed to AOPR from 10 ppmv to 20 ppmv at the stage of HA3T. The order of ethanol-breakthroughs and the order of the magnitude of ethanol-removal efficiencies at the sampling ports of each unit of R reactor at the stages of HA1, HB1, HA2, HB2, and the first half of HA3T, were reversed, respectively, at the stages of the second half of HA3T and HB3T. In case of H2S, R reactor did not show H2S-breakthrough as prominent as the ethanol-breakthrough, but showed the trend similar to the ethanol-breakthrough.

THERMALLY INDUCED PHASE SEPARATION IN TERNARY POLYMER SOLUTION

  • Jung, Bum-Suk;Kang, Yong-Soo;Jones, Richard-A.L.
    • Proceedings of the Membrane Society of Korea Conference
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    • 1999.07a
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    • pp.79-82
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    • 1999
  • Using Small Angle Light Scattering (SALS), the effect of quench depth on the kinetics of phase separation for ternary solution blends was investigated. The system was composed of two polymers (polystyrene and polybutadiene) and a solvent (toluene). The analyses of the early stage of phase separation were based of the Cahn-Hilliard theory [1,5]. Apparent diffusion coefficients and the fastest mode of fluctuations were evaluated, when quench depth of the system were varied near the critical composition of polymer. In the late stage of phase separation, the domain growth showed a power law with the 1/3 exponent, i.e. $q_m(t)~t^{-1/3}$. For comparison between real images and scattering profiles with time, the image of phase domains with time were obtained by using Laser Confocal Scanning Microscopy (LSCM).

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A Hybrid Optimized Deep Learning Techniques for Analyzing Mammograms

  • Bandaru, Satish Babu;Deivarajan, Natarajasivan;Gatram, Rama Mohan Babu
    • International Journal of Computer Science & Network Security
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    • v.22 no.10
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    • pp.73-82
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    • 2022
  • Early detection continues to be the mainstay of breast cancer control as well as the improvement of its treatment. Even so, the absence of cancer symptoms at the onset has early detection quite challenging. Therefore, various researchers continue to focus on cancer as a topic of health to try and make improvements from the perspectives of diagnosis, prevention, and treatment. This research's chief goal is development of a system with deep learning for classification of the breast cancer as non-malignant and malignant using mammogram images. The following two distinct approaches: the first one with the utilization of patches of the Region of Interest (ROI), and the second one with the utilization of the overall images is used. The proposed system is composed of the following two distinct stages: the pre-processing stage and the Convolution Neural Network (CNN) building stage. Of late, the use of meta-heuristic optimization algorithms has accomplished a lot of progress in resolving these problems. Teaching-Learning Based Optimization algorithm (TIBO) meta-heuristic was originally employed for resolving problems of continuous optimization. This work has offered the proposals of novel methods for training the Residual Network (ResNet) as well as the CNN based on the TLBO and the Genetic Algorithm (GA). The classification of breast cancer can be enhanced with direct application of the hybrid TLBO- GA. For this hybrid algorithm, the TLBO, i.e., a core component, will combine the following three distinct operators of the GA: coding, crossover, and mutation. In the TLBO, there is a representation of the optimization solutions as students. On the other hand, the hybrid TLBO-GA will have further division of the students as follows: the top students, the ordinary students, and the poor students. The experiments demonstrated that the proposed hybrid TLBO-GA is more effective than TLBO and GA.

θz Stage Design and Control Evaluation for Wafer Hybrid Bonding Precision Alignment (Wafer Hybrid Bonding 정밀 정렬을 위한 θz 스테이지 설계 및 제어평가)

  • Mun, Jea Wook;Kim, Tae Ho;Jeong, Yeong Jin;Lee, Hak Jun
    • Journal of the Semiconductor & Display Technology
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    • v.20 no.4
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    • pp.119-124
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    • 2021
  • In a situation where Moore's law, which states that the performance of semiconductor integrated circuits doubles every two years, is showing a limit from a certain point, and it is difficult to increase the performance due to the limitations of exposure technology.In this study, a wafer hybrid method that can increase the degree of integration Various research on bonding technology is currently in progress. In this study, in order to achieve rotational precision between wafers in wafer hybrid bonding technology, modeling of θz alignment stage and VCM actuator modeling used for rotational alignment, magnetic field analysis and desgin, control, and evaluation are performed. The system of this study was controlled by VCM actuator, capactive sensor, and dspace, and the working range was ±7200 arcsec, and the in-position and resoultion were ±0.01 arcsec. The results of this study confirmed that safety and precise control are possible, and it is expected to be applied to the process to increase the integration.

Development of a Hybrid fNIRS-EEG System for a Portable Sleep Pattern Monitoring Device (휴대용 수면 패턴 모니터링을 위한 복합 fNIRS-EEG 시스템 개발)

  • Gyoung-Hahn Kim;Seong-Woo Woo;Sung Hun Ha;Jinlong Piao;MD Sahin Sarker;Baejeong Park;Chang-Sei Kim
    • Journal of Biomedical Engineering Research
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    • v.44 no.6
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    • pp.392-403
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    • 2023
  • This study presents a new hybrid fNIRS-EEG system to meet the demand for a lightweight and low-cost sleep pattern monitoring device. For multiple-channel configuration, a six-channel electroencephalogram (EEG) and a functional near-infrared spectroscopy (fNIRS) system with eight photodiodes (PD) and four dual-wavelength LEDs are designed. To enhance the convenience of signal measurement, the device is miniaturized into a patch-like form, enabling simultaneous measurement on the forehead. Due to its fully integrated functionality, the developed system is advantageous for performing sleep stage classification with high-temporal and spatial resolution data. This can be realized by utilizing a two-dimensional (2D) brain activation map based on the concentration changes in oxyhemoglobin and deoxyhemoglobin during sleep stage transitions. For the system verification, the phantom model with known optical properties was tested at first, and then the sleep experiment for a human subject was conducted. The experimental results show that the developed system qualifies as a portable hybrid fNIRS-EEG sleep pattern monitoring device.

A Two-stage Stochastic Programming Model for Optimal Reactive Power Dispatch with High Penetration Level of Wind Generation

  • Cui, Wei;Yan, Wei;Lee, Wei-Jen;Zhao, Xia;Ren, Zhouyang;Wang, Cong
    • Journal of Electrical Engineering and Technology
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    • v.12 no.1
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    • pp.53-63
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    • 2017
  • The increasing of wind power penetration level presents challenges in classical optimal reactive power dispatch (ORPD) which is usually formulated as a deterministic optimization problem. This paper proposes a two-stage stochastic programming model for ORPD by considering the uncertainties of wind speed and load in a specified time interval. To avoid the excessive operation, the schedule of compensators will be determined in the first-stage while accounting for the costs of adjusting the compensators (CACs). Under uncertainty effects, on-load tap changer (OLTC) and generator in the second-stage will compensate the mismatch caused by the first-stage decision. The objective of the proposed model is to minimize the sum of CACs and the expected energy loss. The stochastic behavior is formulated by three-point estimate method (TPEM) to convert the stochastic programming into equivalent deterministic problem. A hybrid Genetic Algorithm-Interior Point Method is utilized to solve this large-scale mixed-integer nonlinear stochastic problem. Two case studies on IEEE 14-bus and IEEE 118-bus system are provided to illustrate the effectiveness of the proposed method.

A Study of Hybrid Rocket for Underwater Operation (수중 운용을 위한 하이브리드 로켓 연구)

  • Woo, KyoungJin;Min, Moonki;Lee, Junghyun;Chu, Bokyoung;Lee, Seunghwan;Kim, Gyeongmin;Kim, Heuijoo;Kim, Jiman;Hwang, Heuiseong;Yoo, Youngjoon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2017.05a
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    • pp.144-147
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    • 2017
  • A hybrid rocket engine capable of thrust throttling and underwater-working was developed for the underwater high-speed vehicle propulsion system. The hybrid rocket engine was designed and made by two types of ground test motor and underwater working motors. An engine performance was verified by the ground tests with the ground test motor and in the case of underwater motors the ground tests and underwater tests were performed. For the underwater operation a two-stage ignition system was adopted and a rupture disc was installed at the end of nozzle for a water-tight just before an ignition. Successful ignition and propulsion were confirmed in the underwater test with the final selected double rupture disc.

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Vehicle Interior Noise Analysis Using Frequency Response Function Based Substructural Method (주파수응답함수의 부분구조합성 법을 이용한 차 실내소음 예측)

  • 허덕재;박태원
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.11 no.4
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    • pp.5-12
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    • 2001
  • This paper presents the simulation methodology of the interior noise of vehicle using the frequency response function based hybrid modeling of the system which consists of multi-subsystem models obtained by the test or analysis. The complex systems such as a trimmed body of high modal density and a powertrain were modeled by using experimental data, and a sub-frame of a vehicle of low modal density was modeled by finite element data. Modeling of the whole system was executed and validated in the two stages. The first stave is combining the trimmed body and the sub-frame, and the second stage is attaching the powertrain, which is a exciting source, to the combined model of the first stage. The input force to the system was modeled as an equivalent force in the virtual space, which was obtained from impedance method using the FRFs of the powertrain and the responses. The interior noise predicted by the proposed method was very close to the direct measurement, which showed feasibility of the proposed modeling procedure. Since the methodology is easily applied to both the transfer path analysis of structure-borne noise and the analysis of noise contribution of a sub-system, it is expected to be a strong tool for design change of a vehicle in the earlier stare.

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