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Experimental Investigation of Scalar Dissipation Rates in Lean Hydrocarbon/Air Premixed Flames
Chen, Yung-Cheng,Bilger, Robert W. The Korean Society of Combustion 2001 한국연소학회지 Vol.6 No.2
Instantaneous, three-dimensional scalar dissipation rates of the reaction progress variable are measured in turbulent premixed Bunsen flames of lean hydrocarbon/air mixtures with the two-sheet, two-dimensional Rayleigh scattering technique. The flames investigated are located in the turbulent flame-front regime on a newly proposed combustion diagram for premixed flames. The conditionally-averaged mean scalar dissipation rates, $N_{\zeta}$ are found to be lower than the calculated laminar values, indicating a locally broadened flame front. In agreement with previous measurements, the maximum of $N_{\zeta}$, decreases strongly with increasing Karlovitz numbers. The conditional probability density functions are close to a log-normal distribution for scalar dissipation rates conditioned at the progress variable value where the scalar dissipation is maximum in unstretched laminar flame calculations. The time scale for the Favre-averaged mean scalar dissipation rate decreases in general across the turbulent flame brush from the unburnt to burnt side.
Effects of UV Assistance on the Properties of Al-Doped ZnO Thin Films Deposited by Sol-Gel Method
Yung-Kuan Tseng,Feng-Ming Pai,Yan-Cheng Chen,Chao-Hsien Wu 대한금속·재료학회 2013 ELECTRONIC MATERIALS LETTERS Vol.9 No.6
We report here the preparation of aluminum doped zinc oxide transparent conductive thin films by a UV-assisted sol-gel method. It was found that UV irradiation creates ozone, which promotes the conductivity and transparency of the films. Boro-silicate glasses are used as substrates; an PGME is used as a solvent; after spin-coating,the films are dried and radiated with UV and then heated to 400°C for decarburization and 500°C for annealing under air. The surface morphologies of the prepared films are observed by FE-SEM and AFM. It was found that the films irradiated with UV-C are smoother and denser. An XRD analysis shows that the films have a typical wurtzite crystalline structure with a c-axis orientation normal to the surface. The electric resistance values measured with a four-point probe show that the films irradiated with UV have better conductivity (at approximately 3.4 × 10−3Ω-cm) than the films that did not undergo UV irradiation. An analysis by visible light spectrometry indicates that the AZO films irradiated with UV are more transparent than the films without UV-irradiation.
Value of CT in the Discrimination of Fatal from Non-Fatal Stercoral Colitis
Cheng-Hsien Wu,Chen-Chih Huang,Li-Jen Wang,Yon-Cheong Wong,Chao-Jan Wang,Wan-Chak Lo,Being-Chuan Lin,Yung-Liang Wan,Chuen Hsueh 대한영상의학회 2012 Korean Journal of Radiology Vol.13 No.3
Objective: Clinical presentation and physical signs may be unreliable in the diagnosis of stercoral colitis (SC). This study evaluates the value of computed tomography (CT) in distinguishing fatal from non-fatal SC. Materials and Methods: Ten patients diagnosed as SC were obtained from inter-specialist conferences. Additional 13 patients with suspected SC were identified via the Radiology Information System (RIS). These patients were divided into two groups; fatal and non-fatal SCs. Their CT images are reviewed by two board-certified radiologists blinded to the clinical data and radiographic reports. Results: SC occurred in older patients and displayed no gender predisposition. There was significant correlation between fatal SC and CT findings of dense mucosa (p = 0.017), perfusion defects (p = 0.026), ascites (p = 0.023), or abnormal gas (p = 0.033). The sensitivity, specificity, and accuracy of dense mucosa were 71%, 86%, and 81%, respectively. These figures were 75%, 79%, and 77% for perfusion defects; 75%, 80%, and 78% for ascites; and 50%, 93%, and 78% for abnormal gas, respectively. Each CT sign of mucosal sloughing and pericolonic abscess displayed high specificity of 100% and 93% for diagnosing fatal SC, respectively. However, this did not reach statistical significance in diagnosing fatal SC. Conclusion: CT appears to be valuable in discriminating fatal from non-fatal SC. Objective: Clinical presentation and physical signs may be unreliable in the diagnosis of stercoral colitis (SC). This study evaluates the value of computed tomography (CT) in distinguishing fatal from non-fatal SC. Materials and Methods: Ten patients diagnosed as SC were obtained from inter-specialist conferences. Additional 13 patients with suspected SC were identified via the Radiology Information System (RIS). These patients were divided into two groups; fatal and non-fatal SCs. Their CT images are reviewed by two board-certified radiologists blinded to the clinical data and radiographic reports. Results: SC occurred in older patients and displayed no gender predisposition. There was significant correlation between fatal SC and CT findings of dense mucosa (p = 0.017), perfusion defects (p = 0.026), ascites (p = 0.023), or abnormal gas (p = 0.033). The sensitivity, specificity, and accuracy of dense mucosa were 71%, 86%, and 81%, respectively. These figures were 75%, 79%, and 77% for perfusion defects; 75%, 80%, and 78% for ascites; and 50%, 93%, and 78% for abnormal gas, respectively. Each CT sign of mucosal sloughing and pericolonic abscess displayed high specificity of 100% and 93% for diagnosing fatal SC, respectively. However, this did not reach statistical significance in diagnosing fatal SC. Conclusion: CT appears to be valuable in discriminating fatal from non-fatal SC.
Efficient Scheme for Secret Hiding in QR Code by Improving Exploiting Modification Direction
( Peng-cheng Huang ),( Yung-hui Li ),( Chin-chen Chang ),( Yanjun Liu ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.5
QR codes as public patent are widely used to acquire the information in various fields. However, it faces security problem when delivering the privacy message by QR code. To overcome this weakness, we propose a secret hiding scheme by improving exploiting modification direction to protect the private message in QR code. The secret messages will be converted into octal digit stream and concealed to the cover QR code by overwriting the cover QR code public message bits. And the private messages can be faithfully decoded using the extraction function. In our secret hiding scheme, the QR code public message still can be fully decoded publicly from the marked QR codes via any standard QR Code reader, which helps to reduce attackers’ curiosity. Experiments show that the proposed scheme is feasible, with high secret payload, high security protection level, and resistant to common image post-processing attacks.
Dynamic System Identification Using a Recurrent Compensatory Fuzzy Neural Network
Chi-Yung Lee,Cheng-Jian Lin,Cheng-Hung Chen,Chun-Lung Chang 대한전기학회 2008 International Journal of Control, Automation, and Vol.6 No.5
This study presents a recurrent compensatory fuzzy neural network (RCFNN) for dynamic system identification. The proposed RCFNN uses a compensatory fuzzy reasoning method, and has feedback connections added to the rule layer of the RCFNN. The compensatory fuzzy reasoning method can make the fuzzy logic system more effective, and the additional feedback connections can solve temporal problems as well. Moreover, an online learning algorithm is demonstrated to automatically construct the RCFNN. The RCFNN initially contains no rules. The rules are created and adapted as online learning proceeds via simultaneous structure and parameter learning. Structure learning is based on the measure of degree and parameter learning is based on the gradient descent algorithm. The simulation results from identifying dynamic systems demonstrate that the convergence speed of the proposed method exceeds that of conventional methods. Moreover, the number of adjustable parameters of the proposed method is less than the other recurrent methods.
Efficient secret sharing scheme with cheater identification based on QR code
( Peng-cheng Huang ),( Chin-chen Chang ),( Yung-hui Li ),( Yanjun Liu ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.10
Secret sharing is an effective way of protecting secret messages. However, the traditional secret sharing schemes are considered meaningless due to malicious people attention which might raise risks. To overcome the weakness, this paper presents an effective secret sharing scheme with the functionality of cheater identification, based on meaningful QR code. The secret message will be split and concealed in the padding region of cover QR codes with the assistance of Latin square and it can be completely restored when all the involved participants cooperate. The concealing strategy exploits the characteristic of Reed-Solomon (RS) code to ensure the strong robustness of generated QR code pseudo-shares. The meaningful QR code pseudo-shares help to reduce the curious of unrelated persons. Some experiments were done to evaluate the performance of proposed scheme. The results showed that the proposed scheme is feasible, efficient and secure compared to the other existing schemes. It also achieves a higher secret payload and maintains stronger robustness.