Browsing by Author "Chang, C. -C."

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A high-payload, reversible data hiding scheme based on histogram modification in JPEG bitstream
(2016)
Liu, X. -L.
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Chang, C. -C.
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Lin, C. -C.
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Yuan, S. -M.
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資訊工程學系
In this paper, we have presented a high-payload, reversible data hiding scheme that is focused on embedding secret data into joint photographic experts group (JPEG) bitstream by using histogram modification. In JPEG, for AC coefficients, 162 different variable length codes (VLCs) are defined and assigned by Huffman coding for all 162 run/size possibilities. After parsing VLC usage in the bitstream, we generated a histogram of run/size. According to a peak point and the nearest zero point of the histogram, the secret data were embedded by modifying the corresponding VLC values slightly. The experimental results and comparing the performance of our scheme with those of other existing schemes demonstrated that the proposed scheme preserved the quality of the image with no distortion and achieved the goal of high embedding capacity.
Estrogen receptor alpha-351 XbaI*G and -397 PvuII*C-related genotypes and alleles are associated with higher susceptibilities of endometriosis and leiomyoma
(2007-02-01)
Hsieh, Y. -Y.
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Wang, Y. -K.
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Chang, C. -C.
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Lin, C. -S.
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生物科技學系
Endometriosis and leiomyoma are both common estrogen-related gynaecological diseases. We aimed to elucidate the association of estrogen receptor alpha (ER alpha)-351 A > G (XbaI) and -397 T > C (PvuII) gene polymorphisms with endometriosis and leiomyoma. Women were divided into three groups: (i) severe endometriosis (n = 112), (ii) leiomyoma (n = 106) and (iii) normal controls (n = 110). Genomic DNA was obtained from peripheral leukocytes. ER alpha-351 A/G XbaI and -397 T/C PvuII polymorphisms were assayed by the method of PCR and restriction fragment length polymorphism (RFLP). Genotypes and allelic frequencies in each group were compared. The genotype/allele frequencies of ER alpha-351 and -397 polymorphisms in endometriosis or leiomyoma groups were different from those of normal controls. ER alpha mutant-related genotypes/alleles (-351G and -397C) presented higher percentages in the endometriosis/leiomyoma population compared with normal controls. Proportions of ER alpha-351 AA/AG/GG genotypes and A/G alleles in each group were (i) 26.8/57.1/16.1 and 55.4/44.6%; (ii) 19.8/52.8/27.4 and 46.2/53.8% and (iii) 33.6/64.6/1.8 and 65.9/34.1%. Proportions of ER alpha-397 TT/TC/CC genotypes and T/C alleles in each group were (i) 24.1/60.7/15.2 and 54.5/45.5%; (ii) 23.6/70.8/5.6 and 59/41% and (iii) 54.5/40/5.5 and 74.5/25.5%. We concluded that ER alpha-351 XbaI*G- and -397 PvuII*C-related genotypes/alleles were correlated with higher susceptibilities of endometriosis or leiomyoma, which might be associated with related pathogeneses.
GaN-based vertical-cavity surface emitting lasers with sub-milliamp threshold and small divergence angle
(2016-12-12)
Yeh, P. S.
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Chang, C. -C.
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Chen, Y. -T.
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Lin, D. -W.
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Liou, J. -S.
A GaN-based vertical-cavity surface emitting laser (VCSEL) structure featuring a silicon-diffusion-defined current blocking layer for lateral confinement is described. Sub-milliamp threshold currents were achieved for both 3- and 5-mu m-aperture VCSELs under continuous-wave operation at room temperature. The vertical cavity was defined by a top dielectric distributed Bragg reflector (DBR) and a bottom epitaxial DBR. The emission spectrum exhibited a single peak at 411.2 nm with a line-width of 0.4nm and a side mode suppression ratio of more than 10 dB before device packaging. The full-width-at-half-maximum divergence angle of the 3-mu m-aperture VCSEL was as small as approximately 5 degrees which is the lowest number reported. These results implied the 3-mu m-aperture VCSEL was in near single-mode operation. Published by AIP Publishing.
Prospective randomized controlled trial comparing treatment efficacy and tolerance of picosecond alexandrite laser with a diffractive lens array and triple combination cream in female asian patients with melasma
(1970-01-01)
Wang, Y. -J.
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Lin, E. -T.
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Chen, Y. -T.
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Chiu, P. -C.
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Lin, B. -S.
Background Recent evidence suggests melasma to be a photoaging disorder. Triple combination creams (TCC: fluocinolone acetonide 0.01%, hydroquinone 4% and tretinoin 0.05%) remain the gold standard treatment. Picosecond alexandrite laser treatment using a diffractive lens array (DLA) has been identified to be effective for improving photoaging conditions. Objective We aimed to compare the efficacy and tolerance of the picosecond alexandrite laser with those of DLA and TCC in female Asian patients with melasma. Methods Twenty-nine patients were randomly assigned to group A1 (3 laser sessions at 4-week intervals), A2 (5 laser sessions at 4-week intervals) or B (TCC daily for at least 8 weeks and then tapered until the final evaluation). The Melasma Area, Severity Index (MASI) score and VISIA were assessed at baseline, week 12 and week 20. By week 20, the follow-up periods for groups A1 and A2 were 3 months and 1 month, respectively. Results Nine, 11 and 6 participants in groups A1, A2 and B completed the study, respectively. MASI scores were significantly improved in all 3 groups at weeks 12 and 20. In groups A1, A2 and B, the improvement rates at week 20 were 53%, 38% and 50%, respectively. VISIA analysis additionally revealed a significant improvement in spots, porphyria, pores and brown spots after 3 laser sessions (P < 0.05). Group A2 showed greater improvements than group A1 in terms of spots, wrinkles and pores; however, only red areas were significantly different (P < 0.001). All side-effects in the 3 groups were transient and gradually subsided after 1-3 months. Conclusion Picosecond alexandrite laser treatment using DLA showed comparable efficacy with TCC for the treatment of melasma. Improvements in texture, spots, wrinkles and pores were observed in the laser groups. Patients with melasma lesions that exhibit telangiectasia may benefit from additional laser treatment sessions.
Prospective randomized controlled trial comparing treatment efficacy and tolerance of picosecond alexandrite laser with a diffractive lens array and triple combination cream in female asian patients with melasma
(2020-03-01)
Wang, Y. -J.
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Lin, E. -T.
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Chen, Y. -T.
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Chiu, P. -C.
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Lin, B. -S.
BackgroundRecent evidence suggests melasma to be a photoaging disorder. Triple combination creams (TCC: fluocinolone acetonide 0.01%, hydroquinone 4% and tretinoin 0.05%) remain the gold standard treatment. Picosecond alexandrite laser treatment using a diffractive lens array (DLA) has been identified to be effective for improving photoaging conditions. ObjectiveWe aimed to compare the efficacy and tolerance of the picosecond alexandrite laser with those of DLA and TCC in female Asian patients with melasma. MethodsTwenty-nine patients were randomly assigned to group A1 (3 laser sessions at 4-week intervals), A2 (5 laser sessions at 4-week intervals) or B (TCC daily for at least 8 weeks and then tapered until the final evaluation). The Melasma Area, Severity Index (MASI) score and VISIA were assessed at baseline, week 12 and week 20. By week 20, the follow-up periods for groups A1 and A2 were 3 months and 1 month, respectively. ResultsNine, 11 and 6 participants in groups A1, A2 and B completed the study, respectively. MASI scores were significantly improved in all 3 groups at weeks 12 and 20. In groups A1, A2 and B, the improvement rates at week 20 were 53%, 38% and 50%, respectively. VISIA((R)) analysis additionally revealed a significant improvement in spots, porphyria, pores and brown spots after 3 laser sessions (P < 0.05). Group A2 showed greater improvements than group A1 in terms of spots, wrinkles and pores; however, only red areas were significantly different (P < 0.001). All side-effects in the 3 groups were transient and gradually subsided after 1-3 months. ConclusionPicosecond alexandrite laser treatment using DLA showed comparable efficacy with TCC for the treatment of melasma. Improvements in texture, spots, wrinkles and pores were observed in the laser groups. Patients with melasma lesions that exhibit telangiectasia may benefit from additional laser treatment sessions.
Vector-field-based deformations for three-dimensional texture synthesis
(2012-06-01)
Su, Y. -L.
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Chang, C. -C.
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Shih, Z. -C.
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Tai, W. -K.
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多媒體工程研究所
A major drawback of conventional approaches to three-dimensional (3D) texture synthesis is the lack of fine-scale deformations in the synthesised results. This study presents a novel vector-field-based deformation approach to synthesising 3D textures with fine-scale deformations. The pre-process of this approach constructs feature vectors and similarity sets of voxels from an input 3D exemplar to accelerate neighbourhood matching. The synthesis process first introduces 3D vector fields for deforming synthesised results. A 3D pyramid synthesis technique integrated with 3D vector fields is then used to synthesise 3D textures. The proposed approach uses only eight neighbourhoods of each voxel for neighbourhood matching. Experimental results show that the proposed approach efficiently synthesises 3D textures with fine-scale deformations.