• 한국군사과학기술학회지
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• 제3권2호
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• pp.166-178
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• 2000

As the 21st century signifies an information-oriented society, the computer integration takes place in all walks of human presence. Needs for computer and network-integrated automation present new challenges in military as well as commercial facility systems engineering. Since the first intelligent building appeared in USA in 1984, it gradually became an essential capability for the building industry requirement these days. Intelligent Building System(IBS) is evolving to be very complex because there are many subsystems such as telecommunication(TC), office automation(OA), building automation(BA), security, construction environments, etc. During the planing phase of IBS development, therefore, a disciplined systems engineering must be performed to analyze stake- holder's requirements to build an optimized system while minimizing trial-and-error expenses and risks. This paper presents a conceptual design of BAS applying systems engineering methods. The contribution of this study includes the development of IBS subsystem specification for building automation subsystem, which is a part of IBS, using the methodology of requirement analysis, functional analysis, synthesis, and verification. A computer-aided systems engineering s/w, RDD-100, was used to improve the system design efficiency and to promote the product design knowledge management for reuse in later design programs.

• Journal of Power Electronics
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• 제16권1호
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• pp.319-328
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• 2016

In this study, we first briefly introduce the effect of circulating current control on the modulation signal of a modular multilevel converter (MMC). The maximum modulation index is also theoretically derived. According to the optimal modulation index analysis and the model in the continuous domain, different DC-side output impedance equivalent models of MMC with/without compensating component are derived. The DC-side impedance of MMC inverter station can be regarded as a series xR + yL + zC branch in both cases. The compensating component of the maximum modulation index is also related to the DC equivalent impedance with circulating current control. The frequency characteristic of impedance for MMC, which is observed from its DC side, is analyzed. Finally, this study investigates the prediction of the DC voltage ripple transfer between two-terminal MMC high-voltage direct current systems under unbalanced conditions. The rationality and accuracy of the impedance model are verified through MATLAB/Simulink simulations and experimental results.

• Journal of Power Electronics
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• 제17권2호
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• pp.453-463
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• 2017

This paper discusses the measurement of frequency response functions for various dc-dc converters. The frequency domain identification procedure is applied to the measured frequency responses. The identified transfer functions are primarily used in developing behavioral models for dc-dc converters. Distributed power systems are based upon such converters in cascade, parallel and several other configurations. The system level analysis of a complete system becomes complex when the identified transfer functions are of high order. Therefore, a certain technique needs to be applied for order reduction of the identified transfer functions. During the process of order reduction, it has to be ensured that the system retains the dynamics of the full order system. The technique used here is based on the Hankel singular values of a system. A systematic procedure is given to retain the maximum energy states for the reduced order model. A dynamic analysis is performed for behavioral models based on full and reduced order frequency responses. The close agreement of results validates the effectiveness of the model order reduction. Stability is the key design objective for any system designer. Therefore, the measured frequency responses at the interface of the source and load are also used to predict stability of the system.

• Journal of Information Processing Systems
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• 제18권5호
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• pp.614-627
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• 2022

Aspect-based sentiment analysis is to discover the sentiment polarity towards an aspect from user-generated natural language. So far, most of the methods only use the implicit position information of the aspect in the context, instead of directly utilizing the position relationship between the aspect and the sentiment terms. In fact, neighboring words of the aspect terms should be given more attention than other words in the context. This paper studies the influence of different position embedding methods on the sentimental polarities of given aspects, and proposes a position embedding interactive attention network based on a long short-term memory network. Firstly, it uses the position information of the context simultaneously in the input layer and the attention layer. Secondly, it mines the importance of different context words for the aspect with the interactive attention mechanism. Finally, it generates a valid representation of the aspect and the context for sentiment classification. The model which has been posed was evaluated on the datasets of the Semantic Evaluation 2014. Compared with other baseline models, the accuracy of our model increases by about 2% on the restaurant dataset and 1% on the laptop dataset.

• 소성∙가공
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• 제33권5호
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• pp.341-347
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• 2024

Many studies have focused on the optimal design of multi-stage forging molds. For optimal design progress, geometry parameters must be automatically modified, and the updated analysis file delivered. However, existing automation processes set and change parameters at the analysis input file stage, limiting them to simpler tasks like 2D shapes and basic process conditions (e.g., friction, elasticity), making it challenging to handle 3D asymmetric shapes. To address these limitations, an automated program was developed that modifies geometry directly in the CAD model, enabling the automation of complex 3D and asymmetrical shapes. In this process, a 3D mold is generated immediately after the drawing is input, automating the design of both the product and the mold without manual intervention. The program's effectiveness was demonstrated in the design and forging analysis of a multi-stage mold for M10 hex head bolts. This fully automated program reduced preprocessing time by approximately 6.7 times and successfully performed sensitivity analysis without manual input.

• 경영과학
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• 제10권2호
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• pp.93-110
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• 1993

Since the manufacturing machines containing information processing capacity by development of ME technology are developed and distributed from the advanced nations, manufacturing automation with manufacturing method which keeps flexibility and productivity is supplied broadly. An introduction of manufacturing automation technology is necessary to solve difficult domestic industry environment due to international competitiveness weakness of products. The aim of this is to search for the successful factors of the manufacturing business which uses too much technology of manufacturing automation and to observe the difference of the successful factors which influence to introduction performance according to the introduction type of automation technology and the strategic type through the empirical analysis.

• Journal of Information Processing Systems
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• 제20권3호
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• pp.296-306
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• 2024

Traditional ecological driving (Eco-Driving) evaluations often rely on mathematical models that predominantly offer subjective insights, which limits their application in real-world scenarios. This study develops a robust, data-driven Eco-Driving evaluation model by integrating dynamic and distributed multi-source data, including vehicle performance, road conditions, and the driving environment. The model employs a combination weighting method alongside K-means clustering to facilitate a nuanced comparative analysis of Eco-Driving behaviors across vehicles with identical energy consumption profiles. Extensive data validation confirms that the proposed model is capable of assessing Eco-Driving practices across diverse vehicles, roads, and environmental conditions, thereby ensuring more objective, comprehensive, and equitable results.

• Structural Engineering and Mechanics
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• 제82권3호
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• pp.271-282
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• 2022

The active learning surrogate model based on adaptive sampling strategy is increasingly popular in reliability analysis. However, most of the existing sampling strategies adopt the trial and error method to determine the size of the Monte Carlo (MC) candidate sample pool which satisfies the requirement of variation coefficient of failure probability. It will lead to a reduction in the calculation efficiency of reliability analysis. To avoid this defect, a new method for determining the optimal size of the MC candidate sample pool is proposed, and a new structural reliability analysis method combining polynomial chaos-based Kriging model (PC-Kriging) with adaptive sampling region is also proposed (PCK-ASR). Firstly, based on the lower limit of the confidence interval, a new method for estimating the optimal size of the MC candidate sample pool is proposed. Secondly, based on the upper limit of the confidence interval, an adaptive sampling region strategy similar to the radial centralized sampling method is developed. Then, the k-means++ clustering technique and the learning function LIF are used to complete the adaptive design of experiments (DoE). Finally, the effectiveness and accuracy of the PCK-ASR method are verified by three numerical examples and one practical engineering example.

• 한국항공운항학회지
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• 제13권2호
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• pp.1-13
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• 2005

The objective of the study is to analyze the pilot's behavior such as preference and management technique to the automation of aircraft through Flight Management Attitude Questionnaire(FMAQ) survey. Participants in the survey are grouped in rank and nationality, and attitudes of those groups toward the automation are analyzed. Previous empirical studies have demonstrated large cross-nation differences in attitudes regarding task performance across several work domains including aviation. Analysis of the survey shows that the pilots in Asia region like the automation and its usage more than the pilots in western and Oceania regions. The trust in the automation is higher among glass cockpit pilots than among the conventional aircraft pilots. More foreign pilots than Korean pilots believe that the automation may deteriorate their flight skills. While more Korean pilots than foreign pilots agree that their flight skills can be kept by manual controls. The pilots also feel that the automated cockpits would require more verbal communications between crew members. For improving the automation management skills and the effective automation usage, the Situation Awareness training and Crew Resource Management(CRM) training are strongly suggested.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2017년도 추계학술발표회
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• pp.211-211
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• 2017