• Smart Structures and Systems
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• v.12 no.3_4
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• pp.251-269
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• 2013

Measurement of deflections of certain bridges is usually hampered by corruption of the GPS signal by multipath associated with passing vehicles, resulting to unrealistically large apparent displacements. Field data from the Gorgopotamos train bridge in Greece and systematic experiments revealed that such bias is due to superimposition of two major effects, (i) changes in the geometry of satellites because of partial masking of certain satellites by the passing vehicles (this effect can be faced with solutions excluding satellites that get temporarily blocked by passing vehicles) and (ii) dynamic multipath caused from reflection of satellite signals on the passing trains, a high frequency multipath effect, different from the static multipath. Dynamic multipath seems to have rather irregular amplitude, depending on the geometry of measured satellites, but a typical pattern, mainly consisting of a baseline offset, wide base peaks correlating with the sequence of main reflective surfaces of the vehicles passing next to the antenna. In cases of limited corruption of GPS signal by dynamic multipath, corresponding to scale distortion of the short-period component of the GPS waveforms, we propose an algorithm which permits to reconstruct the waveform of bridge deflections using a weak fusion of GPS and RTS data, based on the complementary characteristics of the two instruments. By application of the proposed algorithm we managed to extract semi-static and dynamic displacements and oscillation frequencies of a historical railway bridge under train loading by using noisy GPS and RTS recordings. The combination of GPS and RTS is possible because these two sensors can be fully collocated and have complementary characteristics, with RTS and GPS focusing on the long- and short-period characteristics of the displacement, respectively.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.7
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• pp.1039-1046
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• 2017

Campus microgrid is designed and built by considering not only power generation but also power consumption management as connected microgrid type because the main goal of the campus microgrid is to save power consumption costs. There are many functions to achieve the goal and they are mainly to use generation-based functions such as islanding operation for peak management and for emergency events. In power distribution operation, Conservation Voltage Reduction (CVR) is applied in order to reduce power consumption. The CVR is defined as a function for load consumption reduction by voltage reduction in order to reduce peak demands and energy consumption. However, application of CVR to microgrid is difficult because the microgrid cannot control a tap of transformer in a substation and the microgrid normally is not designed with phase modifying equipment like a step-voltage-regulator which can control voltage in power distribution system operation. In addition, an impact of the CVR is depended on load characteristics such as a normal load, a rated power, and synchronous motors. Therefore, this paper proposes an application of CVR using linear voltage control based AVR in campus microgrid with power consumption reduction considering characteristics of load and component in the microgrid. The proposed system can be applied to each buildings by a configuration of power distribution cables; and the application results and CVR factor are presented in this paper.

• Textile Coloration and Finishing
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• v.31 no.3
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• pp.135-146
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• 2019

A series of azo based disperse dyes were synthesized and applied to polyester(PET) fiber in supercritical carbon dioxide($ScCO_2$). Various aniline derivatives were used as diazo component and coupled with glycine ethylester or carbonic acid ethylester derivatives to give azo based disperse dyes. Depending on the various diazo substituents, absorption maxima varied from 415 to 529nm in acetone. Dyeing in $ScCO_2$ was carried out at $120^{\circ}C$ and 250bar pressure for 2hrs with 0.5% o.w.f. of dye concentration. Dyed PET fiber had excellent brightness and good light, washing and perspiration(acid/alkali) fastness properties.

• International journal of advanced smart convergence
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• v.10 no.3
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• pp.257-278
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• 2021

As the definition of the vendor-oriented implementation method, which was utilized in adopting an ERP system, has been centered around the project construction business, it was difficult for the EPR adopting organization to systematically prepare ERP projects and have enough deliberative opportunities to change-related policies. Furthermore, this method does not have a fully standardized construction process. Accordingly, by defining an organization that wants to adopt an ERP system as a customer, this paper develops the customer-based ERP construction process framework that assists both customers and developers who construct the system. For this purpose, this paper reviews the previous research and collects the construction processes of the commercial ERP SW vendor and ERP construction cases while proposing the three-layer process framework to construct ERP through the KJ method. The ERP process framework consists of 7 processes, 32 activities, 141 tasks while providing definitions for concepts of each component. Furthermore, the proposed processes and phases were set in order of the recommended execution, while the activities were suggested as an open-ended type so that the application and usability can be increased and polished by reflecting experts' opinions. The contribution of this study is to standardize the ERP project process by transforming the previous supplier-based ERP construction method into the customer-based one while providing important procedure and activity frameworks that apply to diverse ERP solutions per vendor. At the same time, this study provides an theoretical foundation to develop the construction process for the customer -based Cloud ERP. In practice, At the beginning of the ERP system construction project, it provides communication or process tailoring tools for the stakeholder.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.6
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• pp.123-128
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• 2021

As the spread of DC power distribution systems increases, the occurrence of failures and fire accidents are also increasing. In particular, the ESS fire accident, which is a component of the smart grid, and the fire accident of the solar power system, which is a direct current system, are caused by problems in the electrical connection between system components as the supply of new and renewable energy rapidly increases and old facilities increase. An arc that can cause a direct fire by releasing the induced light and heat has been pointed out as one of the causes of fire. Therefore, the problem of such an arc defect is that it is impossible to block an arc accident in advance with the existing overcurrent circuit breaker and earth leakage circuit breaker. In this paper, we intend to develop a test equipment that satisfies international standardization and to develop a DC arc generator to protect against failure and fire caused by arcing.

• Smart Structures and Systems
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• v.23 no.6
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• pp.641-651
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• 2019

The stochastic stability control of the parameter-excited vibration of an inclined stay cable with multiple modes coupling under random and periodic combined support disturbances is studied by using the direct eigenvalue analysis approach based on the response moment stability, Floquet theorem, Fourier series and matrix eigenvalue analysis. The differential equation with time-varying parameters for the transverse vibration of the inclined cable with control under random and deterministic support disturbances is derived and converted into the randomly and deterministically parameter-excited multi-degree-of-freedom vibration equations. As the stochastic stability of the parameter-excited vibration is mainly determined by the characteristics of perturbation moment, the differential equation with only deterministic parameters for the perturbation second moment is derived based on the $It{\hat{o}}$ stochastic differential rule. The stochastically and deterministically parameter-excited vibration stability is then determined by the deterministic parameter-varying response moment stability. Based on the Floquet theorem, expanding the periodic parameters of the perturbation moment equation and the periodic component of the characteristic perturbation moment expression into the Fourier series yields the eigenvalue equation which determines the perturbation moment behavior. Thus the stochastic stability of the parameter-excited cable vibration under the random and periodic combined support disturbances is determined directly by the matrix eigenvalues. The direct eigenvalue analysis approach is applicable to the stochastic stability of the control cable with multiple modes coupling under various periodic and/or random support disturbances. Numerical results illustrate that the multiple cable modes need to be considered for the stochastic stability of the parameter-excited cable vibration under the random and periodic support disturbances, and the increase of the control damping rather than control stiffness can greatly enhance the stochastic stability of the parameter-excited cable vibration including the frequency width increase of the periodic disturbance and the critical value increase of the random disturbance amplitude.

• Smart Structures and Systems
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• v.23 no.6
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• pp.589-613
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• 2019

Cables are prone to vibration due to their low inherent damping characteristics. Recently, negative stiffness dampers have gained attentions, because of their promising energy dissipation ability. The viscous inertial mass damper (termed as VIMD hereinafter) can be viewed as one realization of the inerter. It is formed by paralleling an inertial mass part with a common energy dissipation element (e.g., viscous element) and able to provide pseudo-negative stiffness properties to flexible systems such as cables. A previous study examined the potential of IMD to enhance the damping of stay cables. Because there are already models for common energy dissipation elements, the key to establish a general model for IMD is to propose an analytical model of the rotary mass component. In this paper, the characteristics of the rotary mass and the proposed analytical model have been evaluated by the numerical and experimental tests. First, a series of harmonic tests are conducted to show the performance and properties of the IMD only having the rotary mass. Then, the mechanism of nonlinearities is analyzed, and an analytical model is introduced and validated by comparing with the experimental data. Finally, a real-time hybrid simulation test is conducted with a physical IMD specimen and cable numerical substructure under distributed sinusoidal excitation. The results show that the chosen model of the rotary mass part can provide better estimation on the damper's performance, and it is better to use it to form a general analytical model of IMD. On the other hand, the simplified damper model is accurate for the preliminary simulation of the cable responses.

• Journal of the Institute of Convergence Signal Processing
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• v.19 no.4
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• pp.174-179
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• 2018

Currently, various security technologies such as fingerprint recognition and face recognition are being developed. However, although many technologies have been developed, the field of incorporating technologies is quite limited. In particular, it is easy to adapt modern security technologies into existing digital systems, but it is difficult to introduce new digital technologies in systems using analog systems. However, if the system can be widely used, it is worth replacing the analog system with the digital system. Therefore, the selected topic is the electronic attendance system. In this paper, a camera is installed to a door to perform a Haar-like feature training for face detecting and real-time face recognition with a Eigenface in principal component analysis(PCA) based face recognition using raspberry pi. The collected data was transmitted to the smartphone using wireless communication, and the application for the viewer who can receive and manage the information on the smartphone was completed.

• Membrane Journal
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• v.31 no.5
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• pp.333-342
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• 2021

A flexible electrochromic device (ECD) is a promising technology that is expected to be applied in various fields such as smart windows. Polymer electrolyte is an important component that determines the bleaching-coloration performance and physical stability of flexible ECDs. In this study, a pore-filled polymer electrolyte membrane (PFPEM) with excellent dimensional stability was developed to effectively fabricate flexible ECDs and improve durability. Polyvinyl acetate, which has excellent adhesion, and polyethylene glycol, which can improve ionic conductivity, were filled in the pores of a porous substrate made of polyethylene, which is inexpensive and has excellent physical and chemical stability. The optimal lithium salt (LiTFSI) content of the prepared PFPEM was determined at about 27 wt%, and it was confirmed to possess excellent dimensional stability, adhesive strength, and ion conductivity close to that of conventional polymer electrolytes. Although the visible light transmittance was lowered by the use of the porous substrate, it was expected to act as an advantage in the colored state.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.10
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• pp.1310-1316
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• 2021

Recently, with the development of artificial intelligence and IoT technology, the importance of video processing such as object tracking, medical imaging, and object recognition is increasing. In particular, the noise reduction technology used in the preprocessing process demands the ability to effectively remove noise and maintain detailed features as the importance of system images increases. In this paper, we provide a modified weight filter based on pixel matching in an AWGN environment. The proposed algorithm uses a pixel matching method to maintain high-frequency components in which the pixel value of the image changes significantly, detects areas with highly relevant patterns in the peripheral area, and matches pixels required for output calculation. Classify the values. The final output is obtained by calculating the weight according to the similarity and spatial distance between the matching pixels with the center pixel in order to consider the edge component in the filtering process.