• 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.

• Journal of Advanced Marine Engineering and Technology
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• 제37권8호
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• pp.977-983
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• 2013

Based on the consideration of the hourly patterns of the electricity power consumption, this study predicted the effectiveness of hybrid power generation system, which is composed with wind power generator and photovoltaic generator. And this case study is performed at Konrido, which is a affiliated island of Kyeongsangnam-do. As the results, it is obvious that it is not efficient to cover the whole electricity power consumption only with any single power generating system, because the hourly patterns of electricity power consumption, wind power generation and photovoltaic generation are quite different. And because the wind is being through almost 24 hours, it is also found out that wind power generating system with storage battery is the most efficient combination for this case study.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제37권9호
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• pp.1099-1107
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• 2013

This study proposes a weight reduction design for urban transit, specifically, a Korean EMU carbody made of aluminum extrusion profiles, according to size optimization and useful material changes. First, the thickness of the under-frame, side-panels, and end-panels were optimized by the size optimization process, and then, the weight of the Korean EMU carbody could be reduced to approximately 14.8%. Second, the under-frame of the optimized carbody was substituted with a frame-type structure made of SMA 570, and then, the weight of the hybrid-type carbody was 3.8% lighter than that of the initial K-EMU. Finally, the under-frame and the roof-panel were substituted with a composite material sandwich to obtain an ultralight hybrid-type carbody. The weight of the ultralight hybrid-type carbody was 30% lighter than that of the initial K-EMU. All the resulting carbody models satisfied the design regulations of the domestic Performance Test Standard for Electrical Multiple Unit.

• Journal of KIISE
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• 제42권11호
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• pp.1314-1321
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• 2015

Mobile devices employ buffer cache mechanisms, just as in computer systems such as desktops or servers, to mitigate the performance gap between main memory and secondary storage. However, DRAM has a problem in that it accelerates battery consumption by performing refresh operations periodically to maintain the stored data. In this paper, we propose a novel buffer cache scheme to increase the battery lifecycle in mobile devices based on a hybrid main memory architecture consisting of DRAM and non-volatile PCM. We also suggest a new buffer cache policy that allocates buffers based on process states to optimize the performance and endurance of PCM. In particular, our algorithm allocates each page to the appropriate position corresponding to the state of the application that owns the page, and tries to ensure a rapid response of foreground applications even with a small amount of DRAM memory. The experimental results indicate that the proposed scheme reduces the elapsed time of foreground applications by 58% on average and power consumption by 23% on average without negatively impacting the performance of background applications.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제37C권11호
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• pp.1011-1019
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• 2012

This paper presents a novel hybrid authentication scheme in the next-generation Tactical Mobile Communication Systems(TMCS) with wireless MSAP mesh networks. The existing centralized and distributed authentication methods for security between MSAPs may have their pros and cons. The centralized authentication method induces overhead from frequent MSAP association which leads to long authentication delay. On the other hand, the distributed authentication method requires initial sharing of the authentication information. Therefore, a more efficient authentication scheme is needed to protect the network from malicious MSAPs and also maximize efficiency of the network security. The proposed scheme provides a hybrid method of efficiently managing the authentication keys in the wireless MSAP mesh network to reduce the induced authentication message exchange overhead. Also, as the authentication method between MSAP and TMFT is different, a method of utilizing the ACR for handling the EAP packets is proposed. In overall, the proposed scheme provides efficient mutual authentication between MSAPs especially for tactical environments and is analyzed through performance evaluation to prove its superiority.

• Journal of the Korea institute for structural maintenance and inspection
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• 제19권3호
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• pp.48-54
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• 2015

In this study, we propose an innovative lateral force distribution building system between tall buildings by utilizing the difference of moment of inertia, resulting the reduction of lateral displacement and the lateral forces in terms of an alternative for the dense human and increased cost of lands in highly integrated city area. A successive collapse prevention means by providing additional bearing plate between connections is proposed. In addition to that, a more economical vibration reduction is expected due to the suggested tuned mass damper on the surface of spacial structure. In the considered verification examples, reduced drifts at the top location of the building systems are validated against static wind pressure loads and static earthquake loads. The suggested hybrid building system will improve the safety and reliability of the new or existing building system in terms of more than 30% reduced drift and vibration through the development of convergence of tall buildings and spatial structures.

• Journal of the Korea institute for structural maintenance and inspection
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• 제22권1호
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• pp.123-128
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• 2018

Girder bridges and slab bridges are equipped with a system consisting of a flexible joint unit, support, inverted T shaped abutment, and a separate connecting slab structure. These systems have problems such as an increase in cost due to frequent breakage of the expansion joints and a decrease in durability due to a structure with low moment redistribution. To improve these problems, propose Inegral and Semi-Integral Hybrid Slab Bridge and examine the safety through structural analysis. As a result of the review, Inegral and Semi-Integral Hybrid Slab Bridge was the section stiffness is small. but it is confirmed that the structural safety, ductility and flexibility are higher than existing bridges because the moment redistribution and the force transmission are surely performed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권12호
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• pp.5904-5927
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• 2019

Many artificial intelligence (AI) techniques have been embedded into various engineering technologies to assist them in achieving different goals. The integration of modern technologies with energy consumption management system and occupant's comfort inside buildings results in the introduction of intelligent building concept. The major aim of this integration is to manage the energy consumption effectively and keeping the occupant satisfied with the internal environment of the building. The last few couple of years have seen many applications of AI techniques for optimizing the energy consumption with maximizing the user comfort in smart buildings but still there is much room for improvement in this area. In this paper, a hybrid of two AI algorithms called firefly algorithm (FA) and genetic algorithm (GA) has been used for user comfort maximization with minimum energy consumption inside smart building. A complete user friendly system with data from various sensors, user, processes, power control system and different actuators is developed in this work for reducing power consumption and increase the user comfort. The inputs of optimization algorithms are illumination, temperature and air quality sensors' data and the user set parameters whereas the outputs of the optimization algorithms are optimized parameters. These optimized parameters are the inputs of different fuzzy controllers which change the status of different actuators according to user satisfaction.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권5호
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• pp.2286-2309
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• 2016

Overlay networks have been widely deployed upon the Internet by Service Providers (SPs) to provide improved network services. However, the interaction between each overlay and traffic engineering (TE) as well as the interaction among co-existing overlays may occur. In this paper, we adopt both non-cooperative and cooperative game theory to analyze these interactions, which are collectively called hybrid interaction. Firstly, we model a situation of the hybrid interaction as an n+1-player non-cooperative game, in which overlays and TE are of equal status, and prove the existence of Nash equilibrium (NE) for this game. Secondly, we model another situation of the hybrid interaction as a 1-leader-n-follower Stackelberg-Nash game, in which TE is the leader and co-existing overlays are followers, and prove that the cost at Stackelberg-Nash equilibrium (SNE) is at least as good as that at NE for TE. Thirdly, we propose a cooperative coalition mechanism based on Shapley value to overcome the inherent inefficiency of NE and SNE, in which players can improve their performance and form stable coalitions. Finally, we apply distinct genetic algorithms (GA) to calculate the values for NE, SNE and the assigned cost for each player in each coalition, respectively. Analytical results are confirmed by the simulation on complex network topologies.

• Journal of Broadcast Engineering
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• 제22권1호
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• pp.15-27
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• 2017

CRA(Conditional Replenishment Algorithm) was proposed to improve the visual quality of SC-MMH(Service Compatible 3DTV using Main and Mobile Hybrid delivery) which is a kind of hybrid 3DTV system and has been standardized by ATSC. In SC-MMH system, reference view and additional view may have different resolutions and/or encoding methods. To reconstruct 3D view, additional view needs to be enlarged as same as reference view. Although the performance of CRA is quite satisfactory, there may exist some blocky artifacts in the enlarged view since it adopts block-shaped processing unit with quad-tree structure. In this paper, we analyze the main causes of blocky artifacts in CRA and show these artifacts can be successfully suppressed by applying the deblocking filter at receiver side.