• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.10
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• pp.161-167
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• 2015

This paper presented an occupancy-based energy saving system for appliance energy saving in smart house. The developed system is composed of a sensing system and a home gateway system. The sensing system is set of wireless sensor nodes which have pyroelectric infrared (PIR) sensor to detect a motion of human and set of smart plugs which measure the current using CT (current transformer) sensor and send the current to home gateway wirelessly. We measured current consumption of appliances in real time using smart plugs, and checked the occupation of residents using occupancy sensors installed on the door and room. The proposed system saves electric energy to switch off the supply power of unnecessary usages in the unoccupied spaces. Experiments conducted have shown that electric energy usage of appliances can be saved about 34% checked by using occupation.

• Journal of Power Electronics
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• v.18 no.2
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• pp.588-603
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• 2018

This paper presents the idea of a smart load that can adjust the input power flow based on the intermittent power available from RESs (Renewable Energy Resources) to regulate the line voltage, and draw a constant power from the grid. To this effect, an innovative power flow controller is presented based on a Resistive ES (Electric Spring) in combination with a PEAT (Power Electronics based Adjustable Transformer), which can effectively shape the load power flow at the subnetwork level. With a PEAT incorporated in the step down transformer at the grid side, the proposed controller can supply non-critical loads through local RESs, and the critical loads can draw a relatively constant power from the grid. If there is an abundance of power produced by the RESs, the controller can supply both non-critical loads and critical loads through the RES, which significantly reduces the power demand from the grid. The principle, practicality, stability analysis, and controller design are presented. In addition, simulation results show that the power flow controller performs well in shaping the load power flow at the subnetwork level, which decreases the power demand on the grid. Experimental results are also provided to show that the controller can be realized.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.2
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• pp.95-101
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• 2017

A simple and practical voltage balance method for a solid-state transformer (SST) is proposed to reduce the voltage difference of cascaded H-bridge converters. The tolerance device components in SST cause the imbalance problem of DC-link voltage in the H-bridge converter. The Max/Min algorithms of voltage balance controller are merged in the controller of an AC/DC rectifier to reduce the voltage difference. The DC-link voltage through each H-bridge converter can be balanced with the proposed control methods. The design and performance of the proposed SST are verified by experimental results using a 30 kW prototype.

• Journal of Magnetics
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• v.16 no.2
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• pp.129-133
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• 2011

This paper shows the entire future market volume of the HTS power industry, one of main smart grid equipment, in the case of the final market penetration ratio reaching 100% in the domestic market (South Korea). In this paper, the market penetration ratio is determined using the judgment method, with the market penetration S-curve induced using the Delphi method and the Product Life Cycle from 2011 (supposed launching year, not realistic physical year), to 2050 (expected final target year). This paper analyzes the HTS market penetration ratio of each stage, apparent innovation, early adapters, and the early/late majority and laggard stage, using the S-curve, thus calculating the total future market volume of HTS equipment in the positive sense. Finally, this paper estimates the quantitative analysis results for the HTS4-items (cable, FCL, transformer, rotation machine) of each year within the domestic market.

• Annual Conference on Human and Language Technology
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• 2019.10a
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• pp.149-152
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• 2019

감성분석이란 입력된 텍스트의 감성을 분류하는 자연어처리의 한 분야로, 최근 CNN, RNN, Transformer등의 딥러닝 기법을 적용한 다양한 연구가 있다. 한국어 감성분석을 진행하기 위해서는 형태소, 음절 등의 추가 자질을 활용하는 것이 효과적이며 성능 향상을 기대할 수 있는 방법이다. 모델 생성에 있어서 아키텍쳐 구성도 중요하지만 문맥에 따른 언어를 컴퓨터가 표현할 수 있는 지식 표현 체계 구성도 상당히 중요하다. 이러한 맥락에서 BERT모델은 문맥을 완전한 양방향으로 이해할 수있는 Language Representation 기반 모델이다. 본 논문에서는 최근 CNN, RNN이 융합된 모델과 Transformer 기반의 한국어 KoBERT 모델에 대해 감성분석 task에서 다양한 성능비교를 진행했다. 성능분석 결과 어절단위 한국어 KoBERT모델에서 90.50%의 성능을 보여주었다.

• Journal of Electrical Engineering and Technology
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• v.9 no.4
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• pp.1240-1247
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• 2014

The applications of Distributed Generation (DG) in a smart distribution grid environment are widely employed especially for power balancing and supporting demand responses. Using these applications can have both positive and negative impacts on the distribution system. The sizing and location of their installations are the issues that should be taken into consideration to gain the maximum benefit from them when considering the economic aspects. This paper presents an application of the Bat Algorithm (BA) for the optimal sizing and siting of DG in a smart distribution power system in order to maximize the Benefit to Cost Ratio (BCR), subjected to system constraints including real and reactive power generation, line and transformer loading, voltage profile, energy losses, fault level as well as DG operating limits. To demonstrate the effectiveness of the proposed methodology and the impact of considering economic issues on DG placement, a simplify 9-bus radial distribution system of the Provincial Electricity Authority of Thailand (PEA) is selected for the computer simulation to explore the benefit of the optimal DG placement and the performance of the proposed approach.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.5
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• pp.233-252
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• 2022

Recently, various studies have been conducted to improve automated vehicle (AV) safety for AVs commercialization. In particular, the scenario method is directly related to essential safety assessments. However, the existing scenario do not have objectivity and explanability due to lack of data and experts' interventions. Therefore, this paper presents the AVs safety assessment extended scenario using real traffic accident data and vision transformer (ViT), which is explainable artificial intelligence (XAI). The optimal ViT showed 94% accuracy, and the scenario was presented with Attention Map. This work provides a new framework for an AVs safety assessment method to alleviate the lack of existing scenarios.

• Smart Media Journal
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• v.12 no.11
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• pp.48-56
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• 2023

The technology of Three-dimensional human posture estimation is used in sports, motion recognition, and special effects of video media. Among various methods for this, multi-view 3D human pose estimation is essential for precise estimation even in complex real-world environments. But Existing models for multi-view 3D human posture estimation have the disadvantage of high order of time complexity as they use 3D feature maps. This paper proposes a method to extend an existing monocular viewpoint multi-frame model based on Transformer with lower time complexity to 3D human posture estimation for multi-viewpoints. To expand to multi-viewpoints our proposed method first generates an 8-dimensional joint coordinate that connects 2-dimensional joint coordinates for 17 joints at 4-vieiwpoints acquired using the 2-dimensional human posture detector, CPN(Cascaded Pyramid Network). This paper then converts them into 17×32 data with patch embedding, and enters the data into a transformer model, finally. Consequently, the MLP(Multi-Layer Perceptron) block that outputs the 3D-human posture simultaneously updates the 3D human posture estimation for 4-viewpoints at every iteration. Compared to Zheng[5]'s method the number of model parameters of the proposed method was 48.9%, MPJPE(Mean Per Joint Position Error) was reduced by 20.6 mm (43.8%) and the average learning time per epoch was more than 20 times faster.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.1
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• pp.9-14
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• 2022

In this study, a smart jack-up system was developed to prevent safety accidents by performing risk analysis when a structure is lifted for maintenance. A quantitative risk analysis program that can analyze the risk using the pairwise comparison matrix analysis method was developed. The risk was analyzed in real-time for the lifting structure by connecting the program with an automatic jack-up system. Displacements were measured by the IR sensor among the components of the automatic jack-up system, and the displacements were provided to the quantitative risk analysis program. To confirm the performance of the smart automatic jack-up system, experiments were conducted on bridge and risk analysis was performed when a superstructure was lifted. A linear variable differential transformer (LVDT) was also installed on the bridge to verify the performance of the smart automatic jack-up system. The maximum displacements were measured using the devices, and the declinations were compared. The performance of the simultaneous operation of the jack-up device was verified by the analysis of variance (ANOVA).

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.252-253
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• 2012

본 연구에서는 단상 1.9 kV/220 V, 2 kVA 용량의 양방향 지능형 반도체 변압기의 새로운 회로구성을 제안하고 그 동작과 성능을 분석한 내용에 대해 기술하고 있다. 제안하는 반도체 변압기는 고압 고주파 AC-DC 정류기와 저압 양방향 DC-AC 컨버터로 구성되어 있으며, 회로적인 특성을 다양하게 분석하기 위하여 먼저 PSIM 소프트웨어를 이용한 시뮬레이션을 실시하였고 이를 기반으로 반도체변압기를 제작하여 실험을 통해 그 동작과 성능을 검증하였다. 제안하는 반도체변압기는 최근 많은 관심이 고조되고 있는 Smart-Grid에 효율적으로 적용 가능할 것으로 보인다.