• Journal of Electrical Engineering and Technology
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• 제9권2호
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• pp.461-470
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• 2014

This paper presents a probabilistic power flow (PPF) analysis method for distribution network incorporating the randomness and correlation of photovoltaic (PV) generation. Based on the multivariate kernel density estimation theory, the probabilistic model of PV generation is proposed without any assumption of theoretical parametric distribution, which can accurately capture not only the randomness but also the correlation of PV resources at adjacent locations. The PPF method is developed by combining the proposed PV model and Monte Carlo technique to evaluate the influence of the randomness and correlation of PV generation on the performance of distribution networks. The historical power output data of three neighboring PV generators in Oregon, USA, and 34-bus/69-bus radial distribution networks are used to demonstrate the correctness, effectiveness, and application of the proposed PV model and PPF method.

• 정보보호학회논문지
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• 제32권5호
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• pp.915-932
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• 2022

개인정보 보호법과 가명정보 처리 가이드라인에 따르면, 서로 다른 결합신청자들이 결합을 희망할 때 Salt값을 포함한 결합키 생성항목의 해시값으로 매핑을 진행한다. 결합키 생성항목의 예시로는 성명, 전화번호, 생년월일, 주소 등의 개인정보가 될 수 있으며, 해시 함수의 특성상 서로 다른 결합신청자들이 이들의 항목을 정확히 동일한 형태로 저장하고 있을 때 문제없이 결합을 진행할 수 있다. 하지만 이러한 기법은 서로 다른 결합신청자들의 데이터베이스 갱신 시점이 달라서 발생하는 주소 변경, 개명 등의 시나리오에서의 결합은 취약하다. 따라서 본 연구에서 우리는 주소 변경, 개명 등의 결합키 생성항목이 갱신된 시나리오에서도 개인정보보호를 만족하는 강건한 결합키 생성기법을 확률적 자료 연계를 통한 임계값을 바탕으로 제안하며, 본 연구 결과를 활용한 국내 빅데이터 및 인공지능 사업의 발전에 기여하고자 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권1호
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• pp.149-165
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• 2013

Current group key agreement protocols, which are often tree-based, have unnecessary delays that are caused when members with low-performance computer systems join a group key computation process. These delays are caused by the computations necessary to balance a key tree after membership changes. An alternate approach to group key generation that reduces delays is the dynamic prioritizing mechanism of queue-based group key generation. We propose an efficient group key agreement protocol and present the results of performance evaluation tests of this protocol. The queue-based approach that we propose is scalable and requires less computational overhead than conventional tree-based protocols.

• 한국멀티미디어학회논문지
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• 제18권4호
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• pp.499-505
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• 2015

Security supports are a significant factor in the design of mobile ad hoc networks. In the dynamic topology where the node changes frequently, private key generation and revocation for newly joining and leaving nodes must be considered. In addition, the identities of individual nodes must be protected as well in mobile networks to avoid personal privacy concerns. This paper proposes ID-based private key revocation scheme and non-interactive key agreement scheme in anonymous MANETs. The proposed scheme provides the user privacy using pseudonyms and private key generation and revocation schemes with consideration of dynamic user changes. Therefore, our schemes can be applied in dynamic and privacy-preserving MANETs which are helpful to share multimedia data.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권7호
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• pp.1737-1753
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• 2013

Current group key agreement protocols, which are often tree-based, have unnecessary delays that are caused when members with low-performance computer systems join a group key computation process. These delays are caused by the computations necessary to balance a key tree after membership changes. An alternate approach to group key generation that reduces delays is the dynamic prioritizing mechanism of queue-based group key generation. We propose an efficient group key agreement protocol and present the results of performance evaluation tests of this protocol. The queue-based approach that we propose is scalable and requires less computational overhead than conventional tree-based protocols.

• 한국항행학회논문지
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• 제12권1호
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• pp.34-45
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• 2008

브로드캐스트 암호화 기법은 공개된 네트워크상에서 멀티미디어, 소프트웨어, 유료 TV 등의 디지털 정보들을 전송하는데 적용되고 있다. 사용자가 디지털 정보를 획득하기 위해서는 브로드캐스터가 키를 생성하고 분배하는 과정이 필요하며, 사용자가 탈퇴나 새로운 가입 시에 효율적인 키 갱신이 필요하게 된다. 임시적인 컨퍼런스 환경은 각 이동 디바이스들 사이에 대하여 전송이 가능하고, 잦은 위치 변화에 따라 키 정보가 유동적으 로 변하는 특성으로 인해 키 관리의 어려움이 있다. 이에 본 논문에서는 임베디드 컴퓨팅 환경에 적용하여 특정한 공간에서 이동 디바이스가 이용될 때 효율적인 키 생성과 키 갱신을 하도록 제안한다.

• Journal of Power Electronics
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• 제15권6호
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• pp.1446-1455
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• 2015

This paper illustrates resonant tank design considerations and the implementation of a LLC resonant converter with a wide battery voltage range based on the fundamental harmonic approximation (FHA) analysis. Unlike the conventional design at zero load, the parameter K (the ratio of the transformer magnetizing inductor L_m to the resonant inductor L_r) of the LLC converter in this paper is designed with two charging points, (V_{o_min}, I_{o_max1}) and (V_{o_max}, I_{o_max2}), according to the battery charging strategy. A 2.9kW prototype with an output voltage range of 36V to 72V dc is built to verify the design. It achieves a peak efficiency of 96%.

• Journal of Power Electronics
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• 제13권5호
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• pp.798-805
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• 2013

This paper presents the control and implementation of the dual-stator-winding induction generator for variable frequency AC (VFAC) generating system. This generator has two sets of stator windings embedded into the stator slots. The power winding produces the VFAC power to feed the loads, and the control winding is connected to the static excitation controller to control the generator for output voltage regulation with speed and load variations. On the basis of the idea of power balance, an instantaneous slip frequency control (ISFC) strategy using the information of both the output voltage and the output power is used in this system. A series of experiments is carried out on a 15 kW prototype for verification. Results show that the system has good static and dynamic performance in a wide speed range, which demonstrates that the ISFC strategy is suitable for this system.

• 한국입자에어로졸학회지
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• 제5권4호
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• pp.171-178
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• 2009

$PM_{2.5}$ is one of critical air pollutants due to its high absorbability of heavy metallic fumes, PAH and bacillary micro organisms. Such a fine particulate matter is often formed through various nucleation processes including condensation. This study attempts to find the nucleation behaviors of $PM_{2.5}$ arisen from coal power stations using a classical heterogeneous Fletcher's theory. The numerical simulation by C-language could approximate the nucleation process of $PM_{2.5}$ from water vapor, of which approach revealed the required energy for embryo formation and embryo size and nucleation rate. As a result of the calculation, it was found that wetting agents could affect the particle nucleation in vapor condensation. In particular, critical contact angle relates closely with the vapor saturation. Particle condensation could be reduced by lowering the angles. The wetting agents aid to decrease the contact angle and surface tensions, thereby may contribute to save the formation energy.

• 대한임베디드공학회논문지
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• 제18권5호
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• pp.217-223
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• 2023

In this paper, we propose a new model for the conditional generation of music, considering key and rhythm, fundamental elements of music. MIDI sheet music is converted into a WAV format, which is then transformed into a Mel Spectrogram using the Short-Time Fourier Transform (STFT). Using this information, key and rhythm details are classified by passing through two Convolutional Neural Networks (CNNs), and this information is again fed into the Music Transformer. The key and rhythm details are combined by differentially multiplying the weights and the embedding vectors of the MIDI events. Several experiments are conducted, including a process for determining the optimal weights. This research represents a new effort to integrate essential elements into music generation and explains the detailed structure and operating principles of the model, verifying its effects and potentials through experiments. In this study, the accuracy for rhythm classification reached 94.7%, the accuracy for key classification reached 92.1%, and the Negative Likelihood based on the weights of the embedding vector resulted in 3.01.