• 전력전자학회논문지
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• 제10권1호
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• pp.61-69
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• 2005

NPC 인버터는 많은 수의 전력용 반도체 소자로 구성되어 있으므로 다른 고장의 유형보다 전력용 반도체 스위치의 고장 발생 가능성이 더욱 크다. 고장발생시에 시스템의 연속적인 운전을 위한 대책의 개발은 매우 필요하며, 이러한 고장은 제안된 방법을 이용함으로써 시스템의 고장 허용 능력을 향상할 수 있다. 제안된 방법은 하나의 전력용 반도체 고장발생시 고장난 전력용 반도체가 포함된 고장상을 직렬 연결된 커패시터의 접속점에 연결한 후 나머지 두상을 이용하여 제어함으로써 직류-링크 전압을 유지하고, 일정한 크기를 가지는 출력 부하상전류를 연속적으로 시스템에 공급할 수 있다. 제안된 방법은 몇가지 특별한 분야에서 값비싼 다른 대안책들보다 더 경제적인 대안이다.

• 전기학회논문지P
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• 제65권3호
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• pp.171-177
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• 2016

Noise problem that occurs in living environment is a big trouble in the economic, social and environmental aspects. In this paper, the filtered-X LMS algorithms, the adjoint LMS algorithms, and the robust adjoint LMS algorithms will be introduced for applications in active noise control(ANC). The filtered-X LMS algorithms is currently the most popular method for adapting a filter when the filter exits a transfer function in the error path. The adjoint LMS algorithms, that prefilter the error signals instead of divided reference signals in frequency band, is also used for adaptive filter algorithms to reduce the computational burden of multi-channel ANC systems such as the 3D space. To improve performance of the adjoint LMS ANC system, an off-line measured transfer function is connected parallel to the LMS filter. This parallel-fixed filter acts as a noise controller only when the LMS filter is abnormal condition. The superior performance of the proposed system was compared through simulation with the adjoint LMS ANC system when the adaptive filter is in normal and abnormal condition.

• Journal of Power Electronics
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• 제18권6호
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• pp.1855-1865
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• 2018

This paper presents a control strategy for voltage-controlled multi-function distributed generation (DG) combined with an active power filter (APF) and a reactive power compensator. The control strategy is based on droop control. As a result of local nonlinear loads, the voltages of the point of common coupling (PCC) and the currents injecting into the grid by the DG are distorted. The power quality of the PCC voltage can be enhanced by using PCC harmonic compensation. In addition, with the PCC harmonic compensation, the DG offers a low-impedance path for harmonic currents. Therefore, the DG absorbs most of the harmonic currents generated by local loads, and the total harmonic distortion (THD) of the grid connected current is dramatically reduced. Furthermore, by regulating the reactive power of the DG, the magnitude of the PCC voltage can be maintained at its nominal value. The performance of the DG with the proposed control strategy is analyzed by bode diagrams. Finally, simulation and experimental results verify the proposed control strategy.

• 통합자연과학논문집
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• 제2권4호
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• pp.243-251
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• 2009

This paper surveys some researches to accomplish on bioinformatics. These researches wish to propose a database architecture combining a general view of bioinformatics data as a graph of data objects and data relationships, with the efficiency and robustness of data management and query provided by indexing and generic programming techniques. Here, these invert the role of the index, and make it a first-class citizen in the query language. It is possible to do this in a structured way, allowing users to mention indexes explicitly without yielding to a procedural query model, by converting functional relations into explicit functions. In the limit, the database becomes a graph, in which the edges are these indexes. Function composition can be specified either explicitly or implicitly as path queries. The net effect of the inversion is to convert the database into a hyperdatabase: a database of databases, connected by indexes or functions. The inversion approach was motivated by their work in biological databases, for which hyperdatabases are a good model. The need for a good model has slowed progress in bioinformatics.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 춘계학술발표회논문집(2)
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• pp.177-182
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• 1997

금속연료가 연소할 때 발생하는 Fission Gas는 주로 직경방향으로의 Swelling을 일으켜 낮은 연소도의 원인이 되어 왔다. 따라서 본 연구에서는 높은 연소도를 갖는 금속연료의 개발을 목적으로 Fission Gas가 Plenum으로 쉽게 방출하는 조직인 Laminar Structure를 갖는 합금의 설계를 연구하였다. 또한 조사 후의 조직안정성을 예측하기 위해 열처리 후의 미세조직의 변화를 관찰하여 조직안정성을 시험하였다. U-10wt.%Zr 합금 중 Zr 원소 대신에 2wt.% 및 3wt.%의 W 또는 Mo을 첨가한 합금을 제조하여 합금원소 첨가의 영향에 따른 미세조직의 변화를 조사하였다. 그 결과 모든 조성의 합금은 Matrix에 있어서 Laminar Structure를 나타내었다. 또한 U-10wt.%Zr에 비해 2wt.% 및 3wt.%W의 W 또는 Mo를 첨가한 합금의 lamina Thickness가 철면 미세해짐을 확인하였다. 특히 U-7wt.%Zr-3wt.%W의 경우는 U-10wt.Zr에 비해 Laminar Thickness가 1/2배까지 감소되었다. 합금원소(W, Mo) 첨가에 의한 Laminar Thickness의 감소는 Fission Gas의 Inter-connected Path가 보다 잘 형성되게 하여 Gas의 방출속도를 증가시켜 Swelling을 감소시킬 것으로 생각된다. 열처리한 금속연료의 미세조직을 비교한 결과를 보면 합금원소(W, Mo)를 첨가한 합금을 50$0^{\circ}C$에서 1000시간동안 열처리한 것을 U-Zr 2원계 합금을 열처리한 것과 비교했을 때 약 1/3배 정도의 Laminar Thickness를 유지하는 것으로 보아 합금원소를 첨가하면 조사 후의 조직안정성에도 크게 기여할 것으로 기대된다.

• 대한수학회보
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• 제58권5호
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• pp.1279-1300
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• 2021

Let P be a finite point set in ℝ² with the set of distance n-chains defined as ∆_n(P) = {(|p₁ - p₂|, |p₂ - p₃|, …, |p_n - p_n+1|) : p_i ∈ P}. We show that for 2 ⩽ n = O_|P|(1) we have ${\mid}{\Delta}_n(P){\mid}{\gtrsim}{\frac{{\mid}P{\mid}^n}{{\log}^{\frac{13}{2}(n-1)}{\mid}P{\mid}}}$. Our argument uses the energy construction of Elekes and a general version of Rudnev's rich-line bound implicit in [28], which allows one to iterate efficiently on intersecting nested subsets of Guth-Katz lines. Let G is a simple connected graph on m = O(1) vertices with m ⩾ 2. Define the graph-distance set ∆_G(P) as ∆_G(P) = {(|p_i - p_j|)_{i,j}∈E(G) : p_i, p_j ∈ P}. Combining with results of Guth and Katz [17] and Rudnev [28] with the above, if G has a Hamiltonian path we have ${\mid}{\Delta}_G(P){\mid}{\gtrsim}{\frac{{\mid}P{\mid}^{m-1}}{\text{polylog}{\mid}P{\mid}}}$.

• International Journal of Advanced Culture Technology
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• 제9권1호
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• pp.7-15
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• 2021

The open space of the healing facility should contribute to the psychological and social healing of the users, provide a social environment for rest, and provide a design factor to support the walking path to move to the destination-connected space. In this paper, I examined the relationship between the environmental elements, spatial devices, and the characteristics of the design factors in the open space for healing facilities. As a research method, based on the analysis of previous studies, a healing facility in modern society was defined, and the relationship between the social support and physical environment factors of the healing facility where open space was considered. Through the consideration of cases, the characteristics of the physical space environment, and the design factors of the open space in the healing facility were categorized. As a result of research, open space in the healing facility is a space to promote a social exchange of users, as a physical form for accommodating psychological and social healing functions, it is necessary to construct the connection of the external space with the internal space.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권11호
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• pp.4122-4144
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• 2021

In this fast-paced technological world, the Internet of Things is a ground breaking technology which finds an immense role in the present electronic world which includes different embedded sensors, devices and most other things which are connected to the Internet. The IoT devices are designed in a way that it helps to collect various forms of data from varied sources and transmit them in digitalized form. In modern era of IoT technology data security is a trending issue which greatly affects the confidentiality of important information. Keeping the issue in mind a novel light encryption strategy known as LCB is designed for IoT devices for optimal security. LCB exploits the benefits of Feistel structure and the architectural benefits of substitution permutation network both to give more security. Moreover, this newly designed technique is tested on (Virtex-7) XC7VX330T FPGA board and it takes much little area of 224 GE (Gate Equivalent) and is extremely fast with very less combinational path delay of 0.877 ns. An in-depth screening confirms the proposed work to promise more security to counter cryptographic attacks. Lastly the Avalanche Effect (AE) of LCB showed as 63.125% and 63.875% when key and plaintext (PT) are taken into consideration respectively.

• Journal of Smart Tourism
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• 제2권2호
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• pp.21-32
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• 2022

This paper shows light on the concept of smart tourism destination as a future of tourism development, especially in the context of problems associated with developing countries. This study substantiates the case of smart tourism development in mountain destinations as an affordable and needed future of the contemporary era. This conceptual study is based on secondary literature on Smart Cities, Smart Tourism Destinations, and Tourism in Himachal Pradesh. The Indian state of Himachal Pradesh has been considered as a study area to acknowledge major tourism-related challenges, especially in mountain locations. Consequently, the dots are connected between existing challenges and solutions that smart tourism holds. It turns out that for the development of mountain tourism destinations such as Himachal Pradesh in the Indian Himalayas, investments in smart infrastructure are required. By developing smart infrastructure, a new USP can be made, a supportive environment for new local businesses, new employment opportunities, enhanced tourist experience and an overall raised standard of living for locals. Considering all factors, it leads to a highly competitive tourism destination. All tourism destinations located in the Himalayan mountains show somewhat the same tourism challenges as Himachal Pradesh, India. Therefore, this paper brightens the path of destination planners towards the development agenda of smart tourism destinations and shows how smart tourism infrastructure can be deployed for better management of tourism destinations.

• 신재생에너지
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• 제17권3호
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• pp.1-7
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• 2021

The Korean government announced various energy policies, such as the to reduce 37% of the business-as-usual (BAU) greenhouse gas emissions by 2030. The policies aim to increase the renewable electricity generation ratio to 20% by 2030. PVT is a hybrid technology, which combines photovoltaic (PV) and solar collectors. It is capable of generating electricity and thermal energy simultaneously. It has a great potential to be used as a renewable and clean solar energy. However, there exists a shortage of space for the installation of PVT systems in Korea. To overcome this, in this paper proposes four types of soundproof wall PVT air channels, which were designed and optimized, based on the CFD (Computation Fluid Dynamic) analysis results. The thermal energy generation for multiple PVT units connected in series and pressure drop sensitivity were analyzed, depending on inlet velocity.