Constructions and Properties of General (k, n) Block-Based Progressive Visual Cryptography

Chih Cheng Wu,Yi-Chin Lin,김천식 한국전자통신연구원 2015 ETRI Journal Vol.37 No.5

Recently, Hou and others introduced a (2, n) block-based progressive visual cryptographic scheme (BPVCS) in which image blocks can be gradually recovered step by step. In Hou and others’ (2, n)-BPVCS, a secret image is subdivided into n non-overlapping image blocks. When t (2 ≤ t ≤ n) participants stack their shadow images, all the image blocks associated with these t participants will be recovered. However, Hou and others’ scheme is only a simple 2-out-of-n) case. In this paper, we discuss a general (k, n)-BPVCS for any k and n. Our main contribution is to give two constructions (Construction 1 and Construction 2) of this general (k, n)-BPVCS. Also, we theoretically prove that both constructions satisfy a threshold property and progressive recovery of the proposed (k, n)-BPVCS. For k = 2, Construction 1 is reduced to Hou and others’ (2, n)-BPVCS.

Speech Enhancement in the Subband Domain

Wu, Wen Rong,Chen, Po Cheng,Wang, Chih Song 대한전자공학회 1994 ISPACS:Intelligent Signal Processing and Communica Vol.1 No.1

The main goal of speech enhancement is to filter speech contaminated by additive white or colored noise. Conventional approach is to model speech as a high order time varying AR process and apply the Kalman filter However, the conventional approach has two problems. First, the high order Kalman filter, which involves intensive matrix computation, is difficult to be implemented. Second, the estimate of AR parameters from noisy speech is not trivial In this paper, we propose new approaches to solve these problems We model subband signals of speech as AR processes and then apply Kalman filter to filter noise. Since the lower order AR models can be used for the subband signals, we can apply a lower order Kalman filter to avoid the intensive computation To solve the second problem, we propose new adaptive algorithms for white or colored noise respectively The new algorithm is also compared with normalized LMS algorithm. Sunulation results show that the speech enhancement w subband domain has ranch better performance than that in fullband domain

Measurement of Deformity at the Craniovertebral Junction: Correlation of Triangular Area and Myelopathy

Chih-Chang Chang,Jau-Ching Wu,Chin-Chu Ko,Hsuan-Kan Chang,Yi-Hsuan Kuo,Chao-Hung Kuo,Tsung-Hsi Tu,Wen-Cheng Huang 대한척추신경외과학회 2022 Neurospine Vol.19 No.4

Objective: Diseases of the craniovertebral junction (CVJ) are commonly associated with deformity, malalignment, and subsequent myelopathy. The misaligned CVJ might cause compression of neuronal tissues and subsequently clinical symptoms. The triangular area (TA), measured by magnetic resonance imaging/images (MRI/s), is a novel measurement for quantification of the severity of compression to the brain stem. This study aimed to assess the normal and pathological values of TA by a comparison of patients with CVJ disease to age- and sex-matched controls. Moreover, postoperative TAs were correlated with outcomes. Methods: Consecutive patients who underwent surgery for CVJ disease were included for comparison to an age- and sex-matched cohort of normal CVJ persons as controls. The demographics, perioperative information, and pre- and postoperative 2-year cervical MRIs were collected for analysis. Cervical TAs were measured and compared. Results: A total of 201 patients, all of whom had pre- or postoperative MRI, were analyzed. The TA of the CVJ deformity group was larger than the healthy control group (1.62 ± 0.57 cm2 vs. 1.01 ± 0.18 cm2 , p < 0.001). Moreover, patients who had combined anterior odontoidectomy and posterior laminectomy with fixation had the greatest reduction in the TA (1.18 ± 0.58 cm2 ). Conclusion: In CVJ deformity, the measurement of the cervical TA could indicate the severity of brain stem compression. After surgery, the TA had a varying degree of improvement, which could represent the efficacy of surgery.

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.

Comparison of Cortical Bone Trajectory to Pedicle-Based Dynamic Stabilization: An Analysis of 291 Patients

Chih-Chang Chang,Hsuan-Kan Chang,Chin-Chu Ko,Ching-Lan Wu,Yi-Hsuan Kuo,Tsung-Hsi Tu,Wen-Cheng Huang,Jau-Ching Wu 대한척추신경외과학회 2023 Neurospine Vol.20 No.1

Objective: Pedicle-based dynamic stabilization (DS) has gained popularity outside of America. Although pedicle screw (PS) loosening has always been a concern, it is reportedly innocuous. Cortical bone trajectory (CBT) screw is an emerging option with less invasiveness and similar effectiveness to PS in short-segment lumbar fusion. This study aimed to verify the use of CBT for DS by comparing the outcomes between pedicle- and CBT-based DS. Methods: Consecutive patients with lumbar spondylosis or low-grade spondylolisthesis who underwent 1- or 2-level DS between L3–5 with a minimum follow-up of 24 months were reviewed. Screw loosening was determined by computed tomography and the incidences were compared. Results: A total of 291 patients who underwent Dynesys DS (235 pedicle- and 56 CBT-based, respectively) were compared. The demographics and preoperative conditions were similar. All the clinical outcomes improved at 24-month postoperation, while the CBT-based group had less operation time and blood loss than the pedicle-based group. The rates of screw loosening were lower in the CBT-based (5.4% per screw and 12.5% per patient) than the pedicle-based group (9% per screw and 26.4% per patient). Furthermore, there were no differences in the clinical outcomes and complication profiles. Conclusion: The CBT-based DS for 1- or 2-level lumbar degeneration demonstrated equivalent clinical improvement as the pedicle-based DS. The adaption of CBT-based screws for DS could be a less invasive approach (shorter operation time and less blood loss), with lower chances of screw loosening than the conventional PS-based DS.

Cross-match as an immuno-oncological risk factor for hepatocellular carcinoma recurrence and inferior survival after living donor liver transplantation: A call for further investigation

Cheng-Maw HO,Rey-Heng HU,Yao-Ming WU,Ming-Chih HO,Po-Huang LEE 한국간담췌외과학회 2021 Annals of hepato-biliary-pancreatic surgery Vol.25 No.-

Smart monitoring system with multi-criteria decision using a feature based computer vision technique

Chih-Wei Lin,Wen-Ko Hsu,Dung-Jiang Chiou,Cheng-Wu Chen,Wei-Ling Chiang 국제구조공학회 2015 Smart Structures and Systems, An International Jou Vol.15 No.6

When natural disasters occur, including earthquakes, tsunamis, and debris flows, they are often accompanied by various types of damages such as the collapse of buildings, broken bridges and roads, and the destruction of natural scenery. Natural disaster detection and warning is an important issue which could help to reduce the incidence of serious damage to life and property as well as provide information for search and rescue afterwards. In this study, we propose a novel computer vision technique for debris flow detection which is feature-based that can be used to construct a debris flow event warning system. The landscape is composed of various elements, including trees, rocks, and buildings which are characterized by their features, shapes, positions, and colors. Unlike the traditional methods, our analysis relies on changes in the natural scenery which influence changes to the features. The “background module” and “monitoring module” procedures are designed and used to detect debris flows and construct an event warning system. The multi-criteria decision-making method used to construct an event warring system includes gradient information and the percentage of variation of the features. To prove the feasibility of the proposed method for detecting debris flows, some real cases of debris flows are analyzed. The natural environment is simulated and an event warning system is constructed to warn of debris flows. Debris flows are successfully detected using these two procedures, by analyzing the variation in the detected features and the matched feature. The feasibility of the event warning system is proven using the simulation method. Therefore, the feature based method is found to be useful for detecting debris flows and the event warning system is triggered when debris flows occur.

A state space meshless method for the 3D analysis of FGM axisymmetric circular plates

Chih-Ping Wu,Yan-Cheng Liu 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.22 No.1

A state space differential reproducing kernel (DRK) method is developed for the three-dimensional (3D) analysis of functionally graded material (FGM) axisymmetric circular plates with simply-supported and clamped edges. The strong formulation of this 3D elasticity axisymmetric problem is derived on the basis of the Reissner mixed variational theorem (RMVT), which consists of the Euler-Lagrange equations of this problem and its associated boundary conditions. The primary field variables are naturally independent of the circumferential coordinate, then interpolated in the radial coordinate using the early proposed DRK interpolation functions, and finally the state space equations of this problem are obtained, which represent a system of ordinary differential equations in the thickness coordinate. The state space DRK solutions can then be obtained by means of the transfer matrix method. The accuracy and convergence of this method are examined by comparing their solutions with the accurate ones available in the literature.

Slide Session : OS-CAD-06 ; Cardiology : Erythrocytosis Increased One-Year Mortality in Patients with St-Segment Elevation Myocardial Infarction Un-dergoing Primary Percutaneous Coronary Intervention

( Cheng Wei Liu ),( Yi Ching Lin ),( Chung Ming Tu ),( Pen Chih Liao ),( Kuan Change Chen ),( Yen Wen Wu ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

Background: Anemia is associated with poor prognosis in patients with ST-segment elevation myocardial infarction(STEMI). However, it is unclear that erythrocytosis has protective effect in these populations. Hence, we conducted a retrospective cohort study to examine the relationship between erythrocytosis and mortality in patients with STEMI undergoing primary percutaneous coronary intervention (PCI ). Materials and Methods: We screened 1,156 consecutive patients with STEMI undergoing primary PCI in a single center during Feb 2007 and January 2012. There were 201 missing data for door-to-balloon time and 4 missing data for hemoglobin. Of 951 analyzable patients, they were divided into anemia (Hemoglobin<13.0mg/dl in men or <12.0mg/dl in women), normal hemoglobin, and erythrocytosis (hemoglobin =16.0mg/dl in men or =15.0mg/dl in women) groups. The study end point was one-year mortality. Results: There were 148, 535, and 268 patients in anemia, normal hemoglobin, and erythrocytosis groups, respectively. Patients in the anemia group were older and had lower body mass index than other two groups. There was more female, smokers, hypertension, and diabetes in the anemia group. One-year mortality rates were 16.2%, 6.5%, 2.6% (P<0.001) respectively. In univariate proportional hazards regression analysis, age, hemoglobin, total cholesterol, statin use, glycoprotein llb/llla inhibitor use, and TIMI risk score were associated with 1-year mortality in three groups. After adjustment for potential confounders, hemoglobin levels remained an independent predictor of one-year mortality in both anemia (hazard ratio 0.697, 95% CI 0.528-0.960) and erythrocytosis group (hazard ratio 3.129, 95% CI 1.1.474-6.642). Conclusions: Patients with STEMI and anemia had the worst outcomes than normal hemoglobin and erythrocytosis groups. Expectedly, hemoglobin had the protective effect on prognosis in anemia group. However, a hemoglobin level was an independent risk factor of one-year mortality in those with erythrocytosis.

Cross-Match as an Immuno-Oncological Risk Factor for Hepatocellular Carcinoma Recurrence and Inferior Survival after Living Donor Liver Transplantation: A Call for Further Investigation

( Cheng-maw Ho ),( Rey-heng Hu ),( Yao-ming Wu ),( Ming-chih Ho ),( Po-Huang Lee ) 대한간학회 2021 춘·추계 학술대회 (KASL) Vol.2021 No.1