• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.853-855
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• 2013

In this paper, we proposed the store monitoring system using smart hanger. This system consists of smart hanger, server, and wireless communication module. The smart hanger consists of LCD, MCU, RF module. In order to verify the effectiveness of the proposed smart hanger, we performed the experiment. This smart hanger can be used for shopping mall to increase sales.

• 전자공학회논문지
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• 제51권8호
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• pp.185-194
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• 2014

본 논문에서는 스마트 옷걸이를 이용한 의류 관리 시스템을 제안하였다. 제안하는 시스템은 스마트 옷걸이, 베이스 모듈, 서버 등으로 구성되며, 스마트 옷걸이는 MCU, LED, RFID 리더기, RF칩, 링센서, 밧데리 등으로 구성된다. 제안하는 시스템은 스마트 옷걸이가 의류에 부착된 RFID 태그를 읽어 무선으로 서버에 전송하면 서버와 연결된 베이스 모듈은 스마트 옷걸이와 통신을 하고 서버에 정보를 전송한다. 서버에서는 DB를 통해 의류를 관리하고 웹페이지 및 스마트폰을 통해 각종 정보를 표시할 수 있다. 제안한 시스템의 유용성을 확인하기 위하여 옷걸이를 많이 사용하는 의류 매장과 세탁소 관리시스템에 대하여 실험을 하였다. 스마트 옷걸이의 성능 실험으로 제안한 저전력 알고리즘을 적용하여 전류 소모량의 감소를 확인하고 배터리 수명을 예측할 수 있었다. 의류 매장 관리시스템은 소비자의 편리성과 판매량 증가를 증대 시킬 수 있다. 세탁소 관리 시스템은 대량의 세탁물 분류의 효율성과 소비자의 편리성을 증대 시킬 수 있다.

• Smart Structures and Systems
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• 제23권6호
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• pp.683-693
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• 2019

In August 2012, during the passage of the typhoon Haikui (1211), large amplitude vibrations were observed on long hangers of the Xihoumen suspension Bridge, which destroyed a few viscoelastic dampers originally installed to connect a pair of hanger ropes transversely. The purpose of this study is to identify the cause of vibration and to develop countermeasures against vibration. Field measurements have been conducted in order to correlate the wind and vibration characteristics of hangers. Furthermore, a replica aeroelastic model of prototype hangers consisting of four parallel ropes was used to study the aeroelastic behavior of hanger ropes and to examine the effect of the rigid spacers on vibration mitigation. It is shown that the downstream hanger rope experiences the most violent elliptical vibration for certain wind direction, and the vibration is mainly attributed to wake interference of parallel hanger ropes. Based on wind tunnel tests and field validation, it is confirmed that four rigid spacers placed vertically at equal intervals are sufficient to suppress the wake-induced vibrations. Since the deployment of spacers on hangers, server hanger vibrations and clash of hanger ropes are never observed.

• Smart Structures and Systems
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• 제17권6호
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• pp.1107-1127
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• 2016

Studies on dynamic characteristics of the hanger vibration using field monitoring data are important for the design and evaluation of high-speed railway truss arch bridges. This paper presents an analysis of the hanger's dynamic displacement responses based on field monitoring of Dashengguan Yangtze River Bridge, which is a high-speed railway truss arch bridge with the longest span throughout the world. The three vibration parameters, i.e., dynamic displacement amplitude, dynamic load factor and vibration amplitude, are selected to investigate the hanger's vibration characteristics in each railway load case including the probability statistical characteristics and coupled vibration characteristics. The influences of carriageway and carriage number on the hanger's vibration characteristics are further investigated. The results indicate that: (1) All the eight railway load cases can be successfully identified according to the relationship of responses from strain sensors and accelerometers in the structural health monitoring system. (2) The hanger's three vibration parameters in each load case in the longitudinal and transverse directions have obvious probabilistic characteristics. However, they fall into different distribution functions. (3) There is good correlation between the hanger's longitudinal/transverse dynamic displacement and the main girder's transverse dynamic displacement in each load case, and their relationships are shown in the hysteresis curves. (4) Influences of the carriageway and carriage number on the hanger's three parameters are different in both longitudinal and transverse directions; while the influence on any of the three parameters presents an obvious statistical trend. The present paper lays a good foundation for the further analysis of train-induced hanger vibration and control.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 춘계학술대회
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• pp.274-277
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• 2012

In this paper, we proposes the design of laundry system for low power and smart management. The low power system configures the network with the RF communication module that turn on/off periodically, power consumption less than operating the module all the time without it toggles. The smart management is RFID Laundry Management System (LMS), in order to provide high services, low operation costs and better monitoring. The proposed system consists of RFID tag, wireless RFID hanger and MFC software. To compare with other existing RFID system, our system was developed as a web application. Therefore, customer can check their cloth status through web page or smartphone devices. RFID reader was designed on hanger to make our system enables reliable running effectively. Some results on the performance of an implementation are presented.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 추계학술대회
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• pp.811-814
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• 2011

본 논문에서는 무선 Radio Frequency Identification (RFID) 리더기 단말을 이용한 대량의 세탁물 및 의류의 효율적인 관리를 위한 스마트 세탁물 관리 시스템을 제안한다. 제안하는 시스템은 크게 무선 RFID 옷걸이, 베이스 모듈, 서버 시스템으로 구성되어지며, RFID 리더기가 부착된 무선 RFID 옷걸이는 세탁물에 부착된 RFID 태그를 읽어 무선으로 서버에 전송한다. 서버와 연결된 베이스 모듈은 무선 RFID 옷걸이와 통신을 하고 서버에 정보를 전송한다. 서버 시스템에서는 DB를 통해 의류를 관리하고 웹페이지 및 스마트폰을 통해 정보를 게시할 수 있다. 제안한 시스템의 무선 센서 노드는 배터리로 동작되기 때문에 전류 소모량을 측정하여 수명을 예측할 수 있다. 본 시스템은 세탁소 이외에도 대량의 의류관리에도 사용되어 질수 있으며, 또한 세탁 과정에서의 효율성을 증대 시킬 수 있는 서비스가 될 것이다.

• Smart Structures and Systems
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• 제31권1호
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• pp.57-68
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• 2023

Bridge hangers, such as those in suspension and cable-stayed bridges, suffer from cumulative fatigue damage caused by dynamic loads (e.g., cyclic traffic and wind loads) in their service condition. Thus, the identification of damage to hangers is important in preserving the service life of the bridge structure. This study develops a new method for condition assessment of bridge hangers. The tension force of the bridge and the damages in the element level can be identified using the Bayesian optimization method. To improve the number of observed data, the additional mass method is combined the Bayesian optimization method. Numerical studies are presented to verify the accuracy and efficiency of the proposed method. The influence of different acquisition functions, which include expected improvement (EI), probability-of-improvement (PI), lower confidence bound (LCB), and expected improvement per second (EIPC), on the identification of damage to the bridge hanger is studied. Results show that the errors identified by the EI acquisition function are smaller than those identified by the other acquisition functions. The identification of the damage to the bridge hanger with various types of boundary conditions and different levels of measurement noise are also studied. Results show that both the severity of the damage and the tension force can be identified via the proposed method, thereby verifying the robustness of the proposed method. Compared to the genetic algorithm (GA), particle swarm optimization (PSO), and nonlinear least-square method (NLS), the Bayesian optimization (BO) performs best in identifying the structural damage and tension force.

• Smart Structures and Systems
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• 제2권2호
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• pp.155-169
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• 2006

In this paper, the application of magnetoelasticity in static tension monitoring for large steel cables is discussed. Magnetoelastic (EM) stress sensors make contact-free tension monitoring possible for hanger cables and post-tensioned cables on suspension and cable-stayed bridges. By quantifying the correlation of magnetic relative permeability with tension and temperature, the EM sensors inspect the load levels in the steel cables. Cable tension monitoring on Qiangjiang (QJ) 4th Bridge demonstrates the reliability of the EM sensors.

• Smart Structures and Systems
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• 제23권5호
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• pp.507-520
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• 2019

In the structural health monitoring field, damage detection has been commonly carried out based on the structural model and the engineering features related to the model. However, the extracted features are often subjected to various errors, which makes the pattern recognition for damage detection still challenging. In this study, an automated damage identification method is presented for hanger cables in a tied-arch bridge using a convolutional neural network (CNN). Raw measurement data for Fourier amplitude spectra (FAS) of acceleration responses are used without a complex data pre-processing for modal identification. A CNN is a kind of deep neural network that typically consists of convolution, pooling, and fully-connected layers. A numerical simulation study was performed for multiple damage detection in the hangers using ambient wind vibration data on the bridge deck. The results show that the current CNN using FAS data performs better under various damage states than the CNN using time-history data and the traditional neural network using FAS. Robustness of the present CNN has been proven under various observational noise levels and wind speeds.

• Smart Structures and Systems
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• 제22권6호
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• pp.727-741
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• 2018

To mitigate vibrations, tuned mass dampers(TMD) are widely used for long span bridges or high-rise buildings. Due to some durability concerns, such as fluid degradation, oil leakage, etc., the alternative solutions, such as the non-contacted eddy current damping (ECD), are proposed for mechanical devices in small scales. In the present study, a new eddy current damping TMD (ECD-TMD) is proposed and developed for large scale civil infrastructure applications. Starting from parametric study on finite element analysis of the ECD-TMD, the new design is enhanced via using the permanent magnets to eliminate the power need and a combination of a copper plate and a steel plate to improve the energy dissipation efficiency. Additional special design includes installation of two permanent magnets at the same side above the copper plate to easily adjust the gap as well as the damping. In a case study, the proposed ECD-TMD is demonstrated in the application of a steel arch bridge to mitigate the wind-induced vibrations of the flexible hangers. After a brief introduction of the configuration and the installation process for the damper, the mitigation effects are measured for the ambient vibration and forced vibration scenarios. The results show that the damping ratios increase to 3% for the weak axis after the installation of the ECD-TMDs and the maximum vibration amplitudes can be reduced by 60%.