• Advances in aircraft and spacecraft science
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• v.6 no.6
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• pp.463-478
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• 2019

The present work investigates the effect on the flow-induced vibrations of the lay-up sequence of composite laminated axisymmetric structures, using an hybrid approach based on a wave finite element and a transfer matrix method. The structural vibrations, under deterministic distributed pressure loads, diffuse acoustic field and turbulent boundary layer excitations, are analysed and compared. A multi-scale approach is used for the dynamic analysis of finite structures, using an elementary periodic subsystem. Different flow regimes and shell curvatures are analysed and the computational efficiency is also discussed.

• Journal of Computing Science and Engineering
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• v.5 no.1
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• pp.19-31
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• 2011

In this paper, we propose two new routing schemes for double-layered peer-to-peer systems; a shorter-lower mobility routing scheme and a reverse path routing scheme. The shorter-lower mobility routing scheme first chooses shortest routing paths among possible routing paths and selects the path associated with the relay peer who has lower mobility to improve the reliability of the system. The reverse path routing scheme carries out unicasting (instead of multicasting) based on the reverse path information that can be obtained during the initial file search to further reduce network traffic. The experimental results showed that a double-layered peer-topeer system with the proposed hybrid scheme improved the reliability of the system about 1.5% over the hop count scheme and reduced network traffic by about 0.5% compared to the hop count scheme.

• Journal of Power Electronics
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• v.13 no.4
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• pp.528-535
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• 2013

Most eco-friendly cars can adopt the concept of an integrated battery charger (IBC), which uses currently available motor drive systems. The IBC has a lot of strong points such as low cost and minimum space for the high voltage battery charger. On the other hand, it also has some defects caused by its structure. In this paper, the shortcomings of the conventional IBC for PHEVs with interior permanent magnet motors are discussed, and two advanced IBCs with improved performance are presented. Compared with the conventional IBC, the two advanced IBCs have plenty of strengths such as low common noise, high efficiency, simple sensing methods, etc. Then, the digital control algorithm is modified and a power loss calculation is carried out with simulation software. Finally, experimental results are provided to show the performance of the IBC systems.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2008.04a
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• pp.29-32
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• 2008

Based on the interval-valued intuitionistic fuzzy hybrid geometric (IIFHG) operator and the interval-valued intuitionistic fuzzy weighted geometric (IIFWG) operator, we investigate the group decision making problems in which all the information provided by the decision-makers is presented as interval-valued intuitionistic fuzzy decision matrices where each of the elements is characterized by interval-valued intuitionistic fuzzy numbers, and the information about attribute weights is partially known. A numerical example is used to illustrate the applicability of the proposed approach.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2000.11a
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• pp.711-727
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• 2000

In this paper, the design of the successive detection logarithmic amplifier(SDLA) is reviewed for radar and EW system, and implemented in hybrid MIC. The SDLA operates over the 5 to 7㎓ frequency range. the unit has a dynamic range of -80㏈m to 0㏈m, a logging accuracy of ±1.4㏈, a legging slope 19.2㎷/㏈, and a gain flatness of ± 1.2㏈. Input VSWR of less than 2, noise figure of 2㏈, video impedance of 900Ω and output voltage range of 0 to 1.53V DC have been obtained over 80㏈ of dynamic range.

• Journal of Korea Society of Industrial Information Systems
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• v.3 no.1
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• pp.239-255
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• 1998

멀티미디어 초고속정보통신망 구축을 위한 가장 적합한 통신방식은 ATM(Asynchronous Transfer Model)으로 음성,영상, 데이터를 실시간, 비실시간 데이터로 구분하여 복합적으로 전송할 수있다. ATM 망은 유선 ATM망과 무선 ATM망으로 나누어지는데 무선 ATM 망의 가장 큰 차이점은 이동성과 전송 환경의 특성으로 발생하는 오류 확률이다. 따라서 무선 ATM 망에서 증가된 오류율을 유선 ATM망 수준으로 감소시키는 것이 매우 필요하다. 본 논문에서는 무선전송환경의 버스트오류에 효과적인 인터리빙 기법을 무선 전송단의 한정된 대역폭에 할당되는 ATM 셀의 가상 회선/경로의 수만감소시켜 일반 ATM 셀과의 연동성을 보장하는 인터리빙 수정 셀 방법을 제안하고 이의 성능을 분석한다. 분석결과 본 논문에서 제안한 방법을 사용하는 경우, 기존 셀에 추가되는 오버헤더 없이 전송성능이 향상되었으며, HARQ(Hybrid Automatic Request)를 적용했을 때 불가능한 실시간 데이터서비스도 가능한 것으로 나타났다.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.140.2-140.2
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• 2011

Renewable energy(RE) systems have difficulties in operating and management due to the intermittency of the energy generation. Stochastic supply profiles of RE creates problems for mechanical and electrical design in relation to the selection of technology types and capacities of RE to be installed. This paper presents an methodology of the feasibility assessment of RE-integrated energy systems on the basis of hourly demand/supply analysis tools. Also, this paper shows the feasibility and the usefulness of GS REMA(Renewable Energy Matching Analysis) and HOMER by comparing actual energy data.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.22-23
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• 2011

As device dimensions shrink, it is increasingly important to develop fabrication methods that can create sub-15 nm features of regular or arbitrary geometry in a rapid, parallel, and efficient process. This talk will discuss approaches based on self-assembling hybrid polymers containing Si. The thin films of those materials systems can generate well-ordered periodic arrays of dots or lines. For achieving, long-range ordering, it is helpful to use lithographically-defined templates, which are in general much larger than the length-scale of self-assembled nanostructures. For example, the self-assembly of polymer nanostructures can easily be templated using an array of nanoscale topographical elements that act as guiding templates or surrogates for one of two microdomains. The solvent-vapor-induced tunability of pattern dimension and morphology will be discussed as well. Those material systems can excellently serve for high-precision self-assembly that can provide good resolution, reliability, and controllability and be considered as an option for a future nanomanufacturing technology.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.4
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• pp.1178-1191
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• 2014

The fault-tolerance routing problem is one of the most important issues in the application of the Internet of Things, and has been attracting growing research interests. In order to maintain the communication paths from source sensors to the macronodes, we present a hybrid routing scheme and model, in which alternate paths are created once the previous routing is broken. Then, we propose an improved efficient and intelligent fault-tolerance algorithm (IEIFTA) to provide the fast routing recovery and reconstruct the network topology for path failure in the Internet of Things. In the IEIFTA, mutation direction of the particle is determined by multi-swarm evolution equation, and its diversity is improved by the immune mechanism, which can improve the ability of global search and improve the converging rate of the algorithm. The simulation results indicate that the IEIFTA-based fault-tolerance algorithm outperforms the EARQ algorithm and the SPSOA algorithm due to its ability of fast routing recovery mechanism and prolonging the lifetime of the Internet of Things.

• Korean System Dynamics Review
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• v.1 no.1
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• pp.103-131
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• 2000

If a system such as a port has a large boundary and complexity, and the system's substance is considered as a black box, forecast accuracy will be very low. Futhermore various components in a port exert significant influence on each other. To copy with these problem the form of structure models were introduced by using SD method. The Competitive Ports Model had several sub-systems consisting of each Unit Port models, and each Unit Port model was made by quantitative, qualitative factors and their feedback loops. The fact that all components of one port have influence on the components of the other ports should be taken into account to construct Competitive Port Models. However, with the current approach that is impossible, and in this paper therefore, models were simplified by HFP adapted to integrate level variables of unit port models. Although many studies on modelling of port competitive situation have been conducted, both theoretical frame and methodology are still very weak. In this study, a new algorithm called ESD(Extensional System Dynamics) for the evaluation of port competition was presented, and applied to simulate port systems in northeast asia.