• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1359-1367
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• 2015

Digital Signage is a service which displays a variety of information or advertizement on digital display connected with communication network in commercial or public places. In this paper, We present a digital signage software solution named Xibo4u providing personalized advertisement. Xibo4u is composed of a server managing category and contents of advertisement, digital displays showing advertisement based on the categories specific to customers, and a smartphone application which enables customers to designate their favorite categories of advertisement. Xibo4u is developed by extending the Xibo open source software.

• Journal of Power Electronics
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• v.18 no.2
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• pp.533-546
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• 2018

This study proposes a comprehensive mathematical model that includes coil-system circuit and loss models for power converters in wireless power transfer (WPT) systems. The proposed model helps in understanding the performance of WPT systems in terms of coil-to-coil efficiency, overall efficiency, and output power capacity and facilitates system performance optimization. Three methods to achieve constant output power for variable-load systems are presented based on system performance analysis. An optimal method can be selected for a specific WPT system by comparing the efficiencies of the three methods calculated with the proposed model. A two-coil 1 kW WPT system is built to verify the proposed mathematical model and constant output power control methods. Experimental results show that when the load resistance varies between 5 and $25{\Omega}$, the system output power can be maintained at 1 kW with a maximum error of 6.75% and an average error of 4%. Coil-to-coil and overall efficiencies can be maintained at above 90% and 85%, respectively, with the selected optimal control method.

• Journal of Power Electronics
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• v.17 no.3
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• pp.716-724
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• 2017

The output voltage of an off-grid inverter is influenced by load current, and the voltage harmonics especially the 5th and 7th are increased with nonlinear loads. In this paper, to attenuate the output voltage harmonics of off-grid inverters with nonlinear loads nearby, a load current feedforward is proposed. It is introduced to a voltage control loop based on the Positive and Negative Sequence Harmonic Regulator (PNSHR) compensation to modify the output impedance at selective frequencies. The parameters of the PNSHR are revised with the output impedance of the off-grid inverter, which minimizes the output impedance of the off-grid inverter. Experimental results verify the proposed method, showing that the output voltage harmonics caused by nonlinear loads can be effectively suppressed.

• Journal of Korea Multimedia Society
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• v.20 no.5
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• pp.808-826
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• 2017

Most of conventional DSS's(Digital Signage Systems) have been built based on LAMP framework. Recent researches have shown that MEAN or MERN stack framework is simpler, more flexible, faster and more suitable for web-based application than LAMP stack framework. In this paper, we propose a design and implementation of MEARN (ME(A+R)N) stack-based real-time digital signage system, MR-DSS, which supports handing real-time tasks like urgent/instant messaging, system status monitoring and so on, efficiently in addition to conventional digital signage CMS service tasks. MR-DSCMS, CMS of MR-DSS, is designed to provide most of its normal services by REST APIs and real-time services like urgent/instant messaging by Socket.IO base under MEARN stack environment. In addition to architecture description of components composing MR-DSS, design and implementation issues are clarified in more detail. Through experimental testing, it is shown that 1) MR-DSS works functionally well, 2) the networking load performance of MR-DSCMS's REST APIs is better compared to a well-known open source Xibo CMS, and 3) real-time messaging via Socket.IO works much faster than REST APIs.

• Structural Engineering and Mechanics
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• v.86 no.5
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• pp.673-686
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• 2023

Determining the properties of pile from cone penetration test (CPT) is costly, and need several in-situ tests. At the present study, two novel hybrid learning models, namely PSO-RF and HHO-RF, which are an amalgamation of random forest (RF) with particle swarm optimization (PSO) and Harris hawks optimization (HHO) were developed and applied to predict the pile set-up parameter "A" from CPT for the design aim of the projects. To forecast the "A," CPT data along were collected from different sites in Louisiana, where the selected variables as input were plasticity index (PI), undrained shear strength (S_u), and over consolidation ratio (OCR). Results show that both PSO-RF and HHO-RF models have acceptable performance in predicting the set-up parameter "A," with R² larger than 0.9094, representing the admissible correlation between observed and predicted values. HHO-RF has better proficiency than the PSO-RF model, with R² and RMSE equal to 0.9328 and 0.0292 for the training phase and 0.9729 and 0.024 for testing data, respectively. Moreover, PI and OBJ indices are considered, in which the HHO-RF model has lower results which leads to outperforming this hybrid algorithm with respect to PSO-RF for predicting the pile set-up parameter "A," consequently being specified as the proposed model. Therefore, the results demonstrate the ability of the HHO algorithm in determining the optimal value of RF hyperparameters than PSO.

• Animal Bioscience
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• v.34 no.8
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• pp.1290-1302
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• 2021

Objective: Follicle selection is an important process in chicken egg laying. Among several small yellow (SY) follicles, the one exhibiting the highest expression of follicle stimulation hormone receptor (FSHR) will be selected to become a hierarchal follicle. The role of lncRNA, miRNA and other non-coding RNA in chicken follicle selection is unclear. Methods: In this study, the whole transcriptome sequencing of SY follicles with different expression levels of FSHR in Jining Bairi hens was performed, and the expression of 30 randomly selected mRNAs, lncRNAs and miRNAs was validated by quantitative real-time polymerase chain reaction. Preliminary studies and bioinformatics analysis were performed on the selected mRNA, lncRNA, miRNA and their target genes. The effect of identified gene was examined in the granulosa cells of chicken follicles. Results: Integrated transcriptomic analysis on chicken SY follicles differing in FSHR expression revealed 467 differentially expressed mRNA genes, 134 differentially expressed lncRNA genes and 34 differentially expressed miRNA genes, and sosondowah ankyrin repeat domain family member A (SOWAHA) was the common target gene of three miRNAs and one lncRNA. SOWAHA was mainly expressed in small white (SW) and SY follicles and was affected by follicle stimulation hormone (FSH) treatment in the granulosa cells. Knockdown of SOWAHA inhibited the expression of Wnt family member 4 (Wnt4) and steroidogenic acute regulatory protein (StAR) in the granulosa cells of prehierarchal follicles, while stimulated Wnt4 in hierarchal follicles. Overexpression of SOWAHA increased the expression of Wnt4 in the granulosa cells of prehierarchal follicles, decreased that of StAR and cytochrome P450 family 11 subfamily A member 1 in the granulosa cells of hierarchal follicles and inhibited the proliferation of granulosa cells. Conclusion: Integrated analysis of chicken SY follicle transcriptomes identified SOWAHA as a network gene that is affected by FSH in granulosa cells of ovarian follicles. SOWAHA affected the expression of genes involved in chicken follicle selection and inhibited the proliferation of granulosa cells, suggesting an inhibitory role in chicken follicle selection.