• Journal of Computing Science and Engineering
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• 제8권2호
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• pp.65-77
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• 2014

To address the problem of multi-target retrieval (MTR) of remote sensing images, this study proposes a new object-level feature representation model. The model provides an enhanced application image representation that improves the efficiency of MTR. Generating the model in our scheme includes processes, such as object-oriented image segmentation, feature parameter calculation, and symbolic image database construction. The proposed model uses the spatial representation method of the extended nine-direction lower-triangular (9DLT) matrix to combine spatial relationships among objects, and organizes the image features according to MPEG-7 standards. A similarity metric method is proposed that improves the precision of similarity retrieval. Our method provides a trade-off strategy that supports flexible matching on the target features, or the spatial relationship between the query target and the image database. We implement this retrieval framework on a dataset of remote sensing images. Experimental results show that the proposed model achieves competitive and high-retrieval precision.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권11호
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• pp.5671-5693
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• 2017

With the rapid development of cloud computing, more and more data owners are motivated to outsource their data to cloud for various benefits. Due to serious privacy concerns, sensitive data should be encrypted before being outsourced to the cloud. However, this results that effective data utilization becomes a very challenging task, such as keyword search over ciphertexts. Although many searchable encryption methods have been proposed, they only support exact keyword search. Thus, misspelled keywords in the query will result in wrong or no matching. Very recently, a few methods extends the search capability to fuzzy keyword search. Some of them may result in inaccurate search results. The other methods need very large indexes which inevitably lead to low search efficiency. Additionally, the above fuzzy keyword search methods do not support access control. In our paper, we propose a searchable encryption method which achieves fuzzy search and access control through algorithm design and Ciphertext-Policy Attribute-based Encryption (CP-ABE). In our method, the index is small and the search results are accurate. We present word pattern which can be used to balance the search efficiency and privacy. Finally, we conduct extensive experiments and analyze the security of the proposed method.

• 유통과학연구
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• 제18권8호
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• pp.89-102
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• 2020

Purpose: Our purpose in this study is to compare the SERVQUAL, SERVPERF, and non-difference score measures and to find out which one is better for measuring the service quality of the multiplex cinema service. We also aim to analyze the structural relationships between service quality, customer satisfaction and customer loyalty. Methodology: For the study, we collected data from respondents who have used the multiplex cinema services and conducted an empirical test. SPSS 18.0 was used for descriptive frequency analysis, reliability analysis, and multiple regression analysis, AMOS 18.0 was used for structural equation modeling analysis of causal relationships among variables introduced in research hypotheses. Results: The main results of this study are as follows. First, we found that the non-difference score measure provided a much better model than did other service-measuring models (SERVQUAL, SERVPERF) in Korean and Chinese multiplex cinema. Second, two service-quality factors (Korea-tangibles and assurance vs. China-tangibles and empathy) between the multiplex cinema service quality factors significantly influenced customer satisfaction, which had a significant effect on customer loyalty in Korean and Chinese multiplex cinema. Conclusions: Based on the results, the authors discuss the implications and limitations of this study and future research directions at the end of the paper.

• Journal of Power Electronics
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• 제18권6호
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• pp.1879-1888
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• 2018

With power level of grid-connected converters rising, the switching frequency of the switching devices is commonly greatly reduced to improve its power capacity. However, this results in serious couplings of the dq current components, which leads to degradation of the static and dynamic performances of grid-connected converters and fluctuations of the reactive power in dynamic processes. In this paper, complex vector models under low switching frequency are established for an L/LCL grid-connected converter, and the relationship between the switching frequency and the coupling degree is analyzed. In addition, a series decoupling current control strategy is put forward. It is shown that the proposed control strategy can eliminate the couplings, improve the performances and have good robustness to parameter variations through static and dynamic characteristics analyses and a sensitivity analysis. Experimental and simulation results also verify the correctness of the theoretical analyses and the superiority of the proposed control strategy.

• Journal of Power Electronics
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• 제19권4호
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• pp.1034-1044
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• 2019

In medium-voltage and high-voltage high-power converters, the switching devices need to operate at a low switching frequency to reduce power loss and increase the power capacity. This increases the delay of the signal sampling and PWM. It also makes the cross-couplings of the d-q current components more severe. In addition, the LCL filter has three cross-coupling loops and is prone to resonance. In order to solve these problems, this paper establishes a complex vector model of an LCL type grid-connected converter. Based on this model, two multiple decoupling current control strategies with passive damping / notch damping are proposed for the LCL type grid-connected converter. The proposed strategies can effectively eliminate the cross-couplings of the converter, achieve independent control of the d-q current components, expand the stable region and suppress the resonance of the LCL filter. Simulation and experimental results verify the correctness of the theoretical analysis and the feasibility of the proposed strategies.

• Journal of Ginseng Research
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• 제46권2호
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• pp.315-319
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• 2022

• Journal of Korean Neurosurgical Society
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• 제58권1호
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• pp.65-71
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• 2015

Objective : Lumbar spinal stenosis is conventionally treated with surgical decompression. However, bilateral decompression and laminectomy is more invasive and may not be necessary for lumbar stenosis patients with unilateral radiculopathy. We aimed to report the outcomes of unilateral laminectomy and bilateral pedicle screw fixation with fusion for patients with lumbar spinal stenosis and unilateral radiculopathy. Methods : Patients with lumbar spinal stenosis with unilateral lower extremity radiculopathy who received limited unilateral decompression and bilateral pedicle screw fixation were included and evaluated using visual analog scale (VAS) pain and the Oswestry Disability Index (ODI) scores preoperatively and at follow-up visits. Ligamentum flavum thickness of the involved segments was measured on axial magnetic resonance images. Results : Twenty-five patients were included. The mean preoperative VAS score was $6.6{\pm}1.6$ and $4.6{\pm}3.1$ for leg and back pain, respectively. Ligamentum flavum thickness was comparable between the symptomatic and asymptomatic side (p=0.554). The mean follow-up duration was 29.2 months. The pain in the symptomatic side lower extremity (VAS score, $1.32{\pm}1.2$) and the back (VAS score, $1.75{\pm}1.73$) significantly improved (p=0.000 vs. baseline for both). The ODI improved significantly postoperatively ($6.60{\pm}6.5$; p=0.000 vs. baseline). Significant improvement in VAS pain and ODI scores were observed in patients receiving single or multi-segment decompression fusion with fixation (p<0.01). Conclusion : Limited laminectomy and unilateral spinal decompression followed by bilateral pedicle screw fixation with fusion achieves satisfactory outcomes in patients with spinal stenosis and unilateral radiculopathy. This procedure is less damaging to structures that are important for maintaining posterior stability of the spine.

• Journal of Ginseng Research
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• 제46권1호
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• pp.156-166
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• 2022

Background: Panax ginseng Meyer (P. ginseng), a herb distributed in Korea, China and Japan, exerts benefits on diverse inflammatory conditions. However, the underlying mechanism and active ingredients remains largely unclear. Herein, we aimed to explore the active ingredients of P. ginseng against inflammation and elucidate underlying mechanisms. Methods: Inflammation model was constructed by lipopolysaccharide (LPS) in C57BL/6 mice and RAW264.7 macrophages. Molecular docking, molecular dynamics, surface plasmon resonance imaging (SPRi) and immunofluorescence were utilized to predict active component. Results: P. ginseng significantly inhibited LPS-induced lung injury and the expression of proinflammatory factors, including TNF-α, IL-6 and IL-1β. Additionally, P. ginseng blocked fluorescencelabeled LPS (LPS488) binding to the membranes of RAW264.7 macrophages, the phosphorylation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPKs). Furthermore, molecular docking demonstrated that ginsenoside Ro (GRo) docked into the LPS binding site of toll like receptor 4 (TLR4)/myeloid differentiation factor 2 (MD2) complex. Molecular dynamic simulations showed that the MD2-GRo binding conformation was stable. SPRi demonstrated an excellent interaction between TLR4/ MD2 complex and GRo (K_D value of 1.16 × 10^-9 M). GRo significantly inhibited LPS488 binding to cell membranes. Further studies showed that GRo markedly suppressed LPS-triggered lung injury, the transcription and secretion levels of TNF-α, IL-6 and IL-1β. Moreover, the phosphorylation of NF-κB and MAPKs as well as the p65 subunit nuclear translocation were inhibited by GRo dose-dependently. Conclusion: Our results suggest that GRo exerts anti-inflammation actions by direct inhibition of TLR4 signaling pathway.

• 한국전통조경학회지
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• 제41권4호
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• pp.21-29
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• 2023

문화예술의 전성기였던 북송시기는 중국 원림사에서 큰 변화를 가져 온 시기이다. 이전 당대(唐代)에 발전하였던 은둔과 사념(思念)들이 문학과 회화 그리고 예술과 결합되며 원림은 예술작품으로 인식되는 경향을 보이고 있다. 특히 북송시기 문학과 예술을 관통한 소식의 등장은 개인적 정원조성을 뛰어넘어 공공원림의 발전과 원림의 다변화에 영향을 주고 그의 오랜 폄적기간들은 지역문화와 특색을 이해하고 원림에 반영하는 계기가 되었다. 이에 본 연구는 다양한 원림을 경영하였던 소식의 사상에 주목하여 그의 폄적생활과 사상의 관계성을 통해 문인으로서의 그의 원림 경영을 살펴보았다. 이를 위해 소식이 경영한 현존하는 혜주의 백학거 원림을 중심으로 소식이 경영한 문인원림의 양태를 살펴본 결과 다음과 같은 특징과 가치를 표출하였다. 첫째, 유불도 삼가(三家)에 능통했던 소식은 백학거의 입지와 원림 구성요소에 사상과 독특한 조망 기법을 결합하여 경관을 즐기고 있다. 고택은 소박한 형태이나 내경과 외경의 결합을 통해 확장성을 지니고 있고 내경은 단일공간으로 인식되도록 구성하되 공간의 중첩적 경험과 다경관의 동시적 감상이 가능하도록 계획되어 있다. 반면 공간에는 반드시 위계를 설정하여 질서를 두고 있다. 둘째, 원림은 지역의 특징을 반영하여 아열대성 식물이 다수 나타나고 있고 건조물과의 색채적 대비를 고려하여 활색생향(活色生香)적 식재 형태가 나타나고 있다. 또한 시의적 정신세계를 원림에 투영하여 심신수양과 이상세계의 탐구적 장소로 원림을 차용하였고 거욕과 수심적 마음수행을 위한 장소로서 식재는 간결하되 특징을 잘 내보일 수 있는 수종을 선별 식재하여 원림 공간에 율동감과 입체감을 주고 있다. 셋째, 백학거는 시대별 변화를 보이고 있으나 근본적으로 후손들에 의해 소식이 조영한 원림의 양태와 원림 요소들이 현존하여 유산적 가치를 확인할 수 있다.