• KEPCO Journal on Electric Power and Energy
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• 제2권4호
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• pp.609-613
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• 2016

전기자동차 배터리 셀들 간의 불균형 충전 문제를 해결하기 위해, 직병렬 하이브리드 충전 구조를 개발하였다. 이 방법은 직렬 부분에 의해 주 충전이 수행되며 병렬 부분에 의해 밸런싱이 수행되는데, 이 때, 직렬 부분은 부피가 크고 무겁지만 병렬 부분은 직렬 부분보다 작고 가볍다. 개별 배터리 셀 전압을 측정하기 위한 센서 어레이, 듀티비 제어를 포함한 IGBT, 그리고 배터리 관리 시스템은 제안된 시스템의 핵심 요소이다.

• Membrane and Water Treatment
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• 제5권1호
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• pp.1-14
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• 2014

A pilot-scale hybrid membrane bioreactor (HMBR) for real municipal wastewater treatment was developed by adding biofilm carriers into a conventional membrane bioreactor, distribution and dynamic changes of the extracellular polymeric substances (EPS) and their roles in membrane fouling were investigated. The results showed that the concentrations of loosely bond EPS (LB-EPS) and tightly bond EPS (TB-EPS) in activated sludge, carrier biofilm and sludge cake layer have been increased significantly with the running time of HMBR, during operation of the HMBR, EPS demonstrated positive correlations with membrane fouling. Compared to TB-EPS, LB-EPS showed more significant correlations with sludge physical properties and specific resistance to filtration (SRF) in HMBR, and thus demonstrated that LP-EPS have a stronger potential of fouling than TB-EPS. It was also found that a lower organic loading in HMBR could result a significant increase in EPS concentration, which would in turn influence membrane fouling in HMBR. This critical investigation would contribute towards a better understanding of the behavior, composition and fouling potential of EPS in HMBR operation.

• Steel and Composite Structures
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• 제34권5호
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• pp.715-732
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• 2020

High-strength steel composite Y-eccentrically braced frame (Y-HSS-EBF) is a novel structural system. In this study, the spatial substructure hybrid simulation test (SHST) method is used to further study the seismic performance of Y-HSS-EBF. Firstly, based on the cyclic loading tests of two single-story single-span Y-HSS-EBF planar specimens, a finite element model in OpenSees was verified to provide a reference for the numerical substructure analysis model for the later SHST. Then, the SHST was carried out on the OpenFresco test platform. A three-story spatial Y-HSS-EBF model was taken as the prototype, the top story was taken as the experimental substructure, and the remaining two stories were taken as the numerical substructure to be simulated in OpenSees. According to the test results, the validity of the SHST was verified, and the main seismic performance indexes of the SHST model were analyzed. The results show that, the SHST based on the OpenFresco platform has good stability and accuracy, and the results of the SHST agree well with the global numerical model of the structure. Under strong seismic action, the plastic deformation of Y-HSS-EBF mainly occurs in the shear link, and the beam, beam-columns and braces can basically remain in the elastic state, which is conducive to post-earthquake repair.

• 한국컴퓨터정보학회논문지
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• 제23권9호
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• pp.35-42
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• 2018

In this paper, we propose an optimal streaming service method based on Hybrid CDN/P2P architecture. Recently, video streaming utilizes a CDN (Content Delivery Network) operation technique based on a Proxy Server, which is an end node located close to a user. However, since CDN has a fixed network traffic bandwidth and data information exchange among CDNs in the network is not smooth, it is difficult to guarantee traffic congestion and quality of image service. In the hybrid CDN/P2P network, a data selection technique is used to select only the data that is expected to be continuously requested among all the data in order to guarantee the QoS of the user who utilizes the limited bandwidth efficiently. In order to search user requested data, this technique effectively retrieves the storage information of the constituent nodes of CDN and P2P, and stores the new image information and calculates the deletion priority based on the request possibility as needed. Therefore, the streaming service scheme proposed in this paper can effectively improve the quality of the video streaming service on the network.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권3호
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• pp.1213-1237
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• 2019

Vehicular Ad-hoc Network (VANET) facilities envision future Intelligent Transporting Systems (ITSs) by providing inter-vehicle communication for metrics such as road surveillance, traffic information, and road condition. In recent years, vehicle manufacturers, researchers and academicians have devoted significant attention to vehicular communication technology because of its highly dynamic connectivity and self-organized, decentralized networking characteristics. However, due to VANET's high mobility, dynamic network topology and low communication coverage, dissemination of large data packets (e.g. multimedia content) is challenging. Clustering enhances network performance by maintaining communication link stability, sharing network resources and efficiently using bandwidth among nodes. This paper proposes a mobility-based, multi-hop clustering algorithm, (MBCA) for multimedia content broadcasting over an IEEE 802.11p-LTE-enabled hybrid VANET architecture. The OMNeT++ network simulator and a SUMO traffic generator are used to simulate a network scenario. The simulation results indicate that the proposed clustering algorithm over a hybrid VANET architecture improves the overall network stability and performance, resulting in an overall 20% increased cluster head duration, 20% increased cluster member duration, lower cluster overhead, 15% improved data packet delivery ratio and lower network delay from the referenced schemes [46], [47] and [50] during multimedia content dissemination over VANET.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.163-177
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• 2021

Numerical simulations of the Vortex-Induced Vibration (VIV) about a large-scale flexible pipe subject to shear flow were carried out in this paper. Efficiency verification was performed firstly, validating that the proposed fluid-structure interaction solution strategy is competent in predicting the VIV response. Then, the VIV characteristics related to multi-mode and spanwise hybrid waveform about the flexible pipe attributed to shear flow were investigated. When inflow velocity rises, higher vibration modes are apt to be excited, and the spanwise waveform easily convertes from a standing-wave-dominated status to a hybrid standing-traveling wave status. The multi-mode or even multiple-dominant-mode is prone to occur, that is, the dominant mode is often followed by several apparent subordinate modes with considerable vibration energy. Hence, the shedding frequencies no longer obey Strouhal law, and vibration trajectories become intricate. According to the motion analysis concerning the coupled cross-flow and in-line vibrations, as well as the corresponding wake patterns, a tight coupling interaction exists between the structural deformation and the wake flow behind the flexible pipe. In addition, the evolution of the vortex tube along the pipe span and a strong 3D effect are observed due to the slenderness of the flexible pipe and the variability of the vortex shedding attributed to the shear flow.

• 제어로봇시스템학회논문지
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• 제13권11호
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• pp.1082-1091
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• 2007

In this paper, we developed a new hybrid mobile robot which can climb stairs and go over thresholds by crawl gait with embedded real-time control software. This robot is also categorized into hybrid robot that has advantages of wheeled mobile robot and legged mobile robot, but adopts gait feature of crocodile named belly crawl. We imitated the belly crawl using four legs of 2 DOF, four omni-directional wheels, and embedded control software which controls legs and wheels. This software is developed using RTAI/Linux, real-time drivers. As a result, the new hybrid mobile robot has crawl gait. Using this feature, the new hybrid mobile robot can climb stairs and go over thresholds just by path planning of each leg with size of stairs and thresholds, and computing the movement distance of robot body center without considering stability. The performance of our new hybrid mobile robot is verified via experiments.

• Smart Structures and Systems
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• 제19권4호
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• pp.341-350
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• 2017

Based on the super elastic properties of the shape memory alloy (SMA) and the inverse piezoelectric effect of piezoelectric (PZT) ceramics, a kind of hybrid semi-active control device was designed and made, its mechanical properties test was done under different frequency and different voltage. The local search ability of genetic algorithm is poor, which would fall into the defect of prematurity easily. A kind of adaptive immune memory cloning algorithm(AIMCA) was proposed based on the simulation of clone selection and immune memory process. It can adjust the mutation probability and clone scale adaptively through the way of introducing memory cell and antibody incentive degrees. And performance indicator based on the modal controllable degree was taken as antigen-antibody affinity function, the optimization analysis of damper layout in a space truss structure was done. The structural seismic response was analyzed by applying the neural network prediction model and T-S fuzzy logic. Results show that SMA and PZT friction composite damper has a good energy dissipation capacity and stable performance, the bigger voltage, the better energy dissipation ability. Compared with genetic algorithm, the adaptive immune memory clone algorithm overcomes the problem of prematurity effectively. Besides, it has stronger global searching ability, better population diversity and faster convergence speed, makes the damper has a better arrangement position in structural dampers optimization leading to the better damping effect.

• International Journal of Naval Architecture and Ocean Engineering
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• 제8권4호
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• pp.398-408
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• 2016

Based on non-completely hybrid flow line scheduling of panel block in shipbuilding, several uncertain factors influencing the problem were analyzed in a real environment, and a nonlinear integer programming model was built for each sub-scheduling problem. To narrow the difference between theory and application, rolling horizon and rescheduling methods are proposed. Moreover, with respect to the uncertainty of processing time, arriving time and due time, we take the minimizing of the early and delayed delivery costs as the objective, and establish an evaluation with a global penalty function. Finally, numerical experiments and a simulation analysis were undertaken to demonstrate the effectiveness of the model and algorithm.

• 대한전자공학회논문지SD
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• 제44권11호
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• pp.56-64
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• 2007

본 논문은 CMOS-나노 혼성 소자들 중 실현 가능성이 높은 CMOL 회로 설계 자동화 전용 시스템을 최초로 제안한다. CMOL 아키텍처는 NOR 게이트를 이용하여 조합회로의 구현한다. 이 CMOS-나노 혼성 구조는 논리 함수 및 연결 구조가 동일 나노 소자 하드웨어 자원을 공유하는 특징을 가진 새로운 설계 자동화 문제를 제기한다. CMOL의 물리 설계 자동화를 위해 먼저 CMOL 하드웨어 아키텍처 모델을 개발하고 이 CMOL 구조를 위한 배치 배선 문제에서 CMOL만의 특수한 제약조건을 도출하였으며 배치 알고리즘과 게이트 지정 알고리즘을 루프 형태로 조합하여 해를 구하는 접근 방법을 제안하였다. 제안된 접근 방법을 사용하여 CMOL 나노 전자 아키텍처를 위한 전용 설계 자동화 시스템을 개발하였으며 이 시스템을 이용하여 마이크로프로세서 설계에 실제 사용되는 모듈들을 구현함으로써 그 효용성을 증명하였다.