Current Ripple Reduction Technique of DC/DC Converter

Ye-Then Chang,Chia-An Yeh,Masahiro Hamaogi,Fumikazu Takahashi,Yen-Shin Lai 전력전자학회 2007 ICPE(ISPE)논문집 Vol.- No.-

This paper presents a novel method to reduce the current ripple caused by the variation of inductor for a DC/DC converter. The presented method is to increase the switching frequency to keep constant current ripple when the inductance changes. Therefore, no extra component is required. The problem will be described first and the related method is presented. An experimental DC/DC converter is implemented which is with input voltage of 12 V, output voltage of 1.5 V, output current of 10 A, and switching frequency of 200-250 ㎑. Finally, experimental results derived from the designed digital-controlled DC/DC converter are included for confirmation.

Blocking of Cell Proliferation, Cytokines Production and Genes Expression Following Administration of Cordyceps Sinensis in the Bronchoalveolar Lavage Fluids Cells

Kuo, Yuh-Chi,Wu, Chia-Lin,Tasi, Wei-Jern,Wang, Jir-Yenn,Chang, Shi-Chung,Lin, Ching-Yuang,Shiao, Ming-Shi 경희대학교 동서의학연구소 1999 INTERNATIONAL SYMPOSIUM ON EAST-WEST MEDICINE Vol.1999 No.1

Yuh-Chi Kuo¹,Chia-Lin Wn¹,Wei-jern Tasi¹,Jir-Yenn Wang²,Shi-Chung Chang₃,Ching-Yung Lin⁴,and Ming-Shi Shiao⁴¹National Research Institute of Chinese Medicine, ²Department of Biology,Fu Jen University, ³Department of Chest, ⁴Department of Pediatrics, □De[art,amt of Medical Research and Education. Taipei Veterans General Hospital, Taipei, Taiwan Yuh-Chi Kuo¹,Chia-Lin Wn¹,Wei-jern Tasi¹,Jir-Yenn Wang²,Shi-Chung Chang²,Ching-Yung Lin³,and Ming-Shi Shiao⁴.¹National Research Institute of Chinese Medicine, ²Department of Biology,Fu Jen University, ³Department of Chest, ⁴Department of Pediatrics, □De[art,amt of Medical Research and Education. Taipei Veterans General Hospital, Taipei, Taiwan. Blocking of Cell Proliferation, Cytokines Production and Genes Expression Following Administration of Cordyceps sinensis in the Bronchoalveolar Lavage Fluids Cells. Proceedings of international Symposium on East-West Medicine, Seoul. 44-64, 1999.-Cordyceps sinensis is a major parasitic fungus on larva of Lepidoptera. It is one of the well know fungi used in traditional Chinese medicine for treatment asthma, lung and kideney diseases. Many fungi belonging to the genus Cordyceps have been demonstrated to produce natural products with various biological activities. Reported biological activities of genus cordyceps include:(a)inhibition of DNA and RNA synthesis;(b)enhancement of cell differentiation;(c)restruction of cytoskeleton;(d)inhibition of protein kinase activity;(e)antitumor activity on bladder, colon, lung carcinoma as well as fibroblastoma;(f)inhibition of the infection and revers transciptase activity of human immunodeficiency virus type 1; and(g) inhibition of methylation of nucleic acid. Thus, it is suggested that the extracts of Cordyceps sp. Contain antitumor, antiviral, and many other biological activities. In our previous studies, we proved that C. sinensis contains the antitumor and immunomodulatory agents. In the present studies, effects of C. sinensis on bronchoalveolar lavage fluids(BAL)cells were demonstrated. The crude methanolic extracts of C. sinensis were fractionated into 15 fractions by silica gel column chromatography. Effects of various fraction on BAL cells proliferation and lipopolysaccharide(LPS) stimulated interleukin-1β(IL-8),platelet activating factor(PAF), interleukin-6(IL-6), tumor necrosis factor-α(TNF-α),and interleukin-8(IL-8) production on BAL cells were determined. The result indicated that the CS-19-22 fraction suppressed BAL cells proliferation activated by LPS. The median inhibitory concentration(IC50) was 6㎍/ml. The CS-19-22 fraction also decreased IL-1β,PAF,IL-6, TNF-αand IL-8 production.The results of revers transcription-polymerase chain reaction(RT-PCR) demonstrated that the CS-19-22 fraction did not affect IL-1β,PAF,IL-6, TNF-α,and IL-8 mRNAs expression in BAL cells activated by LPS. By contrast, it inhibited the IL-10 mRNA expression but enhanced IFN-γand IL-12 mRNAs expression in activated BAL cells. Moreover, the CS-19-22 fraction blocked PAF-induced platelet aggregation. It is unlikely that cytotoxicity was involved. Because no cell deths were observable. We hypothesize that inhibitory mechanisms of CS-19-22 on BAL cells proliferation may be related to the impairments of gene expression and production of cytokines in BAL cells. The explanation of C. sinensis antiasthma function may involved the following(1)C.sinenesis contained immunomodulatory agents that stimulated IFN-γand IL-12 expression in TH1cells.(2)Enhanced secretion of IFN-γand IL-12 will inhibit the Tγcells immune responses Ex. Decreasing of IL-6 and IL-10 production.(3) The impairments of cytokines production in TH2 cells suppressed th BAL cells proliferation then more cytokines production Ex.IL-1β,PAF,IL-6,TNF-αand IL-8 in activated BAL cells were decreased. (4)The suppression of TH2cells immune responses will inhibit the growth and differentiation of B cells then IgE production will be decreased. (5)Reduced production of IgE will decreased asthma attack occurring in individuals. However, the results of the present study suggested that C. sinensis may also have acted to treat asthma in part by inhibiting BAL cells proliferation and cytokine gene expression and production. Future, experiments with treatment of animals with asthma with C. sinensis will be necessary to defined whether C. sinensis can reduce asthma injury. Plans are underway for the isolation of pure principal growth inhibitors and their mechanisms of action are subjected for further study.

Modal tracking of seismically-excited buildings using stochastic system identification

Chia-Ming Chang,Jau-Yu Chou 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.26 No.4

Investigation of structural integrity has been a critical issue in the field of civil engineering for years. Visual inspection is one of the most available methods to explore deteriorative components in structures. Still, this method is not applicable to invisible damage of structures. Alternatively, system identification methods are capable of tracking modal properties of structures over time. The deviation of these dynamic properties can serve as indicators to access structural integrity. In this study, a modal tracking technique using frequency-domain system identification from seismic responses of structures is proposed. The method first segments the measured signals into overlapped sequential portions and then establishes multiple Hankel matrices. Each Hankel matrix is then converted to the frequency domain, and a temporal-average frequency-domain Hankel matrix can be calculated. This study also proposes the frequency band selection that can divide the frequency-domain Hankel matrix into several portions in accordance with referenced natural frequencies. Once these referenced natural frequencies are unavailable, the first few right singular vectors by the singular value decomposition can offer these references. Finally, the frequency-domain stochastic subspace identification tracks the natural frequencies and mode shapes of structures through quick stabilization diagrams. To evaluate performance of the proposed method, a numerical study is carried out. Moreover, the long-term monitoring strong motion records at a specific site are exploited to assess the tracking performance. As seen in results, the proposed method is capable of tracking modal properties through seismic responses of structures.

INVESTIGATING THE DEVELOPMENT OF BRAND LOYALTY IN BRAND COMMUNITIES FROM A POSITIVE PSYCHOLOGY PERSPECTIVE

Chia-Wu Lin,Kai-Yu Wang,Shu-Hao Chang,Jin-An Lin 글로벌지식마케팅경영학회 2016 Global Marketing Conference Vol.2016 No.7

Brand communities have been increasingly used by marketers to build brands. A brand community can be defined as a “…group of consumers with a shared enthusiasm for the brand and a well-developed social identity, whose members engage jointly in group actions to accomplish collective goals and/or express mutual sentiments and commitments” (Bagozzi and Dholakia, 2006, p. 45). Recent research on brand communities has begun to identify the importance of consumers’ psychological processes in regard to developing successful brand communities. Based on the flow theory from positive psychology, we propose that flow could be generated by brand community characteristics and plays an important role in influencing brand community members’ attitudes toward the brand. Specifically, we propose a model that identifies brand community characteristics (i.e., community cohesiveness and information quality) that produce flow experience and how the flow experience impacts brand identification and brand loyalty. Members from 31 automobile brand communities participated in this survey study, and 580 validated questionnaires were returned. Structural Equation Model was used to test the research hypotheses. The results show that community cohesiveness and information quality positively directly influence brand identification and also indirectly influence brand identification via flow. Flow also positively influences members’ brand identification and, subsequently, impacts brand loyalty. The results from our research contribute to the branding, brand community, and flow theory literature.

Joint Space-Time Kalman Filtering Technique for Global Positioning System Receivers

Chia-Chang Hu,Shin-Chieh Kuo 대한전자공학회 2006 ITC-CSCC :International Technical Conference on Ci Vol.2006 No.2

An Adaptive Robust LMS Employing Fuzzy Step Size and Partial Update in Dynamic-Fading Multipath Channels

Chia-Chang Hu,Hsuan-Yu Lin,Yu-Fan Chen,Jyh-Hong Wen 대한전자공학회 2005 ITC-CSCC :International Technical Conference on Ci Vol.2005 No.3

Feasibility of using a rotating packed bed in preparing coupled ZnO/SnO2 photocatalysts

Chia-Chang Lin,Yu-Ju Chiang 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.4

In this work, coupled ZnO/SnO2 photocatalysts were prepared in a rotating packed bed (RPB) via coprecipitation. The precursors of coupled ZnO/SnO2 photocatalysts were formed from solutions of zinc sulfate, tin tetrachloride and sodium hydroxide. The calcinations of these precursors yielded coupled ZnO/SnO2 photocatalysts. The effect of calcination temperature on the characteristics and photocatalytic activity of coupled ZnO/SnO2 photocatalysts was studied. The photocatalytic activity of coupled ZnO/SnO2 photocatalysts was evaluated using the photocatalytic decolorization of methylene blue. The experimental results reveal that coupled ZnO/SnO2 photocatalysts that were obtained by calcination at 600 8C for 10 h were the most efficient in decolorizing methylene blue.

Dynamic Pilot Arrangement Scheme in Wireless OFDM Systems

Chia-Chang Hu,Hong-Da Shih 대한전자공학회 2008 ITC-CSCC :International Technical Conference on Ci Vol.2008 No.7

An adaptive pilot-symbol assignment scheme is proposed for interpolation-based channel estimation in wireless orthogonal frequency division multiplexing (OFDM) communication systems. The channel transfer functions of data tones are interpolated by the piecewiselinear and the second-order polynomial interpolation methods due to their inherent simplicity. Simulations are conducted to demonstrate system performance and bandwidth (BW) superiority. A comparative evaluation of the proposed dynamic pilot scheme with conventional fixed pilot-symbol channel estimation schemes is performed as well.

Impacts of label quality on performance of steel fatigue crack recognition using deep learning-based image segmentation

Chia-Ming Chang,Shun-Hsiang Hsu,Ting-Wei Chang 국제구조공학회 2022 Smart Structures and Systems, An International Jou Vol.29 No.1

Structural health monitoring (SHM) plays a vital role in the maintenance and operation of constructions. In recent years, autonomous inspection has received considerable attention because conventional monitoring methods are inefficient and expensive to some extent. To develop autonomous inspection, a potential approach of crack identification is needed to locate defects. Therefore, this study exploits two deep learning-based segmentation models, DeepLabv3+ and Mask R-CNN, for crack segmentation because these two segmentation models can outperform other similar models on public datasets. Additionally, impacts of label quality on model performance are explored to obtain an empirical guideline on the preparation of image datasets. The influence of image cropping and label refining are also investigated, and different strategies are applied to the dataset, resulting in six alternated datasets. By conducting experiments with these datasets, the highest mean Intersection-over-Union (mIoU), 75%, is achieved by Mask R-CNN. The rise in the percentage of annotations by image cropping improves model performance while the label refining has opposite effects on the two models. As the label refining results in fewer error annotations of cracks, this modification enhances the performance of DeepLabv3+. Instead, the performance of Mask R-CNN decreases because fragmented annotations may mistake an instance as multiple instances. To sum up, both DeepLabv3+ and Mask R-CNN are capable of crack identification, and an empirical guideline on the data preparation is presented to strengthen identification successfulness via image cropping and label refining.

Semi-active damped outriggers for seismic protection of high-rise buildings

Chia-Ming Chang,Billie F. Spencer, Jr.,Zhihao Wang,Zhengqing Chen 국제구조공학회 2013 Smart Structures and Systems, An International Jou Vol.11 No.5

High-rise buildings are a common feature of urban cities around the world. These flexible structures frequently exhibit large vibration due to strong winds and earthquakes. Structural control has been employed as an effective means to mitigate excessive responses; however, structural control mechanisms that can be used in tall buildings are limited primarily to mass and liquid dampers. An attractive alternative can be found in outrigger damping systems, where the bending deformation of the building is transformed into shear deformation across dampers placed between the outrigger and the perimeter columns. The outrigger system provides additional damping that can reduce structural responses, such as the floor displacements and accelerations. This paper investigates the potential of using smart dampers, specifically magnetorheological (MR) fluid dampers, in the outrigger system. First, a high-rise building is modeled to portray the St. Francis Shangri-La Place in Philippines. The optimal performance of the outrigger damping system for mitigation of seismic responses in terms of damper size and location also is subsequently evaluated. The efficacy of the semi-active damped outrigger system is finally verified through numerical simulation.