• 한국분말재료학회지
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• 제27권2호
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• pp.139-145
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• 2020

The powder manufacturing process using the gas atomizer process is easy for mass production, has a fine powder particle size, and has excellent mechanical properties compared to the existing casting process, so it can be applied to various industries such as automobiles, electronic devices, aviation, and 3D printers. In this study, a modified A4032-xSn (x = 0, 1, 3, 5, and 10 wt.%) alloy with low melting point properties is investigated. After maintaining an argon (Ar) gas atmosphere, the main crucible is tilted; containing molten metal at 1,000℃ by melting the master alloy at a high frequency, and Ar gas is sprayed at 10 bar gas pressure after the molten metal inflow to the tundish crucible, which is maintained at 800℃. The manufactured powder is measured using a particle size analyzer, and FESEM is used to observe the shape and surface of the alloy powder. DSC is performed to investigate the change in shape, according to the melting point and temperature change. The microstructure of added tin (Sn) was observed by heat treatment at 575℃ for 10 min. As the content of Sn increased, the volume fraction increased to 1.1, 3.1, 6.4, and 10.9%.

• 전기전자학회논문지
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• 제12권2호
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• pp.75-80
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• 2008

There are many researches to reduce power consumption of battery-operated Transceiver for 2.4 GHz smartRF applications. However, components such as processor, memory and LCD based power managements reach the limit of reducing power consumption. To overcome the limit, this research proposes novel low-power Transceiver and transceiver Hardware Design. Experimental results in the real smartRF Transceiver show that the proposed methods can reduce power consumption additionally than component based power managements.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.844-847
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• 2007

전 세계적으로 환경에 대한 관심이 고조되는 가운데 각 산업에서의 환경보호를 위한 노력이 꾸준히 진행되고 있다. 건설분야에서도 환경보존 을 노력이 지속되고 있는 실정이다. 이에 본 논문에서는 친환경성, 고내구성, 가변성, 갱신성능 그리고 쾌적성 등의 종합적인 성능을 갖춤으로써 미래형 건축물의 기본요소가 될 수 있는 친환경 지능형 건축 Component system 제안을 위한 요소기술 분석에 초점을 맞추었다. 친환경 지능형 건축 Component system 개발을 위해 요구되는 성능을 파악한 후 그 성능을 구현시키기 위한 요소기술을 분석한 결과, SI주택과 Home Automation 기술이 주요 요소기술로 도출되었다. 그리고 이론 및 문헌 고찰을 통해 도출된 요소기술의 개념 및 개발동향에 대하여 대해 살펴본 후 최종적으로 이러한 기술요소의 융합을 통한 친환경 지능형 건축 Component system 을 제안하였다.

• 정보보호학회논문지
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• 제32권6호
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• pp.1103-1112
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• 2022

블록체인 기술은 일상생활을 비롯한 여러 산업 분야에서 활용도가 증가하고 있으며, 이는 분산원장 기술을 통하여 네트워크 참여자들 간의 거래 내역에 대한 정보의 무결성과 투명성을 보장한다. 무결성과 투명성을 보장하는데 가장 중요한 요소인 분산원장은 스마트 컨트랙트를 통하여 수정, 관리된다. 그러나, 스마트 컨트랙트 또한 블록체인 네트워크의 구성요소인 만큼 참여자들에게 투명하게 공개되고 있었으며 이로 인해 취약점이 쉽게 노출될 수 있었다. 이러한 단점을 보완하기 위하여 신뢰실행환경을 활용하여 기밀성을 보장하는 연구가 다양하게 진행되었으나, 실행된 스마트 컨트랙트의 무결성을 보장하기에는 어려움이 따른다. 해당 논문에서는 이러한 문제를 해결하기 위하여 신뢰 실행환경내에서 실행되는 스마트 컨트랙트의 제어 흐름 무결성을 검증 함으로써 스마트 컨트랙트의 기밀성과 무결성을 동시에 제공하는 것을 목표로 한다.

• International Journal of Computer Science & Network Security
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• 제21권9호
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• pp.103-108
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• 2021

The emergence of new technologies and their implementation by different manufacturers of electronic devices are experiencing an ascending trend. Most of the time, these protocols are expected to reach a certain degree of maturity, and electronic equipment manufacturers use simplified communication standards and interfaces that have already reached maturity in terms of their development such as ModBUS, KNX or CAN. This paper proposes an IoT solution of the Smart Home type based on an Analysis and Prediction System. A data acquisition component was implemented and there was defined an algorithm for the analysis and prediction of actions based on the values collected from the data update component and the data logger records.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집 특별세미나,특별/일반세션
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• pp.547-556
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• 2009

In this paper, we tried to find the engineering feasibility of the component functions of the seven selected application technologies which are going to be installed on the next generation high speed train as the IT and smart sensor application technologies. The component functions of the seven applications, including the "Emergency or reminder notification", were identified and analyzed. In order to justify the feasibility of applications development, effect analysis and sufficiency analysis were performed. In effect analysis, how each function has an effect on safety, convenience, and efficiency of the passengers and attendants was evaluated. In sufficiency analysis, the importance and implementability of each function as a component was evaluated. The feasibility analysis was focused on the technical aspects of the functions. The following work will be the settlement of the final applications that are going to be designed and implemented. This will be done by studying the strategic feasibility in relation to the service or business of the high speed train.

• 전자통신동향분석
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• 제34권5호
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• pp.36-47
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• 2019

Smart window technology has become a major component of smart buildings, leading to energy savings and enhanced functionality. Smart windows work like curtains or blind screens, blocking external light sources. Smart window components employ electrochromic or photochromic materials that can selectively block sunlight when electricity is applied. The installation of low-E glass and building-integrated photovoltaics (BIPV) is being encouraged in accordance with the policy on saving building energy. To incorporate BIPV into smart windows, the transparency and colors of transparent photovoltaics must be optimized. The power sources required to operate these smart windows take advantage of the transparent color of the solar cells, which also facilitates aesthetics. Self-powered smart windows that combine electrochromic or photochromic screens with transparent solar cells suggest a promising convergent technology.

• Smart Structures and Systems
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• 제31권4호
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• pp.335-349
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• 2023

Bridges constantly undergo deterioration and damage, the most common ones being concrete damage and exposed rebar. Periodic inspection of bridges to identify damages can aid in their quick remediation. Likewise, identifying components can provide context for damage assessment and help gauge a bridge's state of interaction with its surroundings. Current inspection techniques rely on manual site visits, which can be time-consuming and costly. More recently, robotic inspection assisted by autonomous data analytics based on Computer Vision (CV) and Artificial Intelligence (AI) has been viewed as a suitable alternative to manual inspection because of its efficiency and accuracy. To aid research in this avenue, this study performs a comparative assessment of different architectures, loss functions, and ensembling strategies for the autonomous segmentation of bridge components and damages. The experiments lead to several interesting discoveries. Nested Reg-UNet architecture is found to outperform five other state-of-the-art architectures in both damage and component segmentation tasks. The architecture is built by combining a Nested UNet style dense configuration with a pretrained RegNet encoder. In terms of the mean Intersection over Union (mIoU) metric, the Nested Reg-UNet architecture provides an improvement of 2.86% on the damage segmentation task and 1.66% on the component segmentation task compared to the state-of-the-art UNet architecture. Furthermore, it is demonstrated that incorporating the Lovasz-Softmax loss function to counter class imbalance can boost performance by 3.44% in the component segmentation task over the most employed alternative, weighted Cross Entropy (wCE). Finally, weighted softmax ensembling is found to be quite effective when used synchronously with the Nested Reg-UNet architecture by providing mIoU improvement of 0.74% in the component segmentation task and 1.14% in the damage segmentation task over a single-architecture baseline. Overall, the best mIoU of 92.50% for the component segmentation task and 84.19% for the damage segmentation task validate the feasibility of these techniques for autonomous bridge component and damage segmentation using RGB images.

• Smart Structures and Systems
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• 제15권4호
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• pp.1139-1158
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• 2015

This paper proposes an efficient system identification method for modeling nonlinear behavior of civil structures. This method is developed by integrating three different methodologies: principal component analysis (PCA), artificial neural networks, and fuzzy logic theory, hence named PANFIS (PCA-based adaptive neuro-fuzzy inference system). To evaluate this model, a 3-story building equipped with a magnetorheological (MR) damper subjected to a variety of earthquakes is investigated. To train the input-output function of the PANFIS model, an artificial earthquake is generated that contains a variety of characteristics of recorded earthquakes. The trained model is also validated using the1940 El-Centro, Kobe, Northridge, and Hachinohe earthquakes. The adaptive neuro-fuzzy inference system (ANFIS) is used as a baseline. It is demonstrated from the training and validation processes that the proposed PANFIS model is effective in modeling complex behavior of the smart building. It is also shown that the proposed PANFIS produces similar performance with the benchmark ANFIS model with significant reduction of computational loads.

• Journal of Communications and Networks
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• 제14권6호
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• pp.606-613
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• 2012

In a smart grid environment, data for the usage and control of power are transmitted over an Internet protocol (IP)-based network. This data contains very sensitive information about the user or energy service provider (ESP); hence, measures must be taken to prevent data manipulation. Mutual authentication between devices, which can prevent impersonation attacks by verifying the counterpart's identity, is a necessary process for secure communication. However, it is difficult to apply existing signature-based authentication in a smart grid system because smart meters, a component of such systems, are resource-constrained devices. In this paper, we consider a smart meter and propose an efficient mutual authentication protocol. The proposed protocol uses a matrix-based homomorphic hash that can decrease the amount of computations in a smart meter. To prove this, we analyze the protocol's security and performance.