Browsing by Author "Chen, Yen-Chung"

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Advanced automated optical inspection system for fishtail collapse of microrouter
(2008)
Perng, Der-Baau
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Chen, Yen-Chung
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工業工程與管理學系
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Department of Industrial Engineering and Management
In this paper, an innovative automated optical inspection (AOI) system is proposed to detect fishtail collapse of various fishtail images. Up to the present, there is no report on the inspection of fishtail collapse by using an AOI system. The proposed AOI system is the first system that can inspect the fishtail collapse of microrouter. The fishtail image of the microrouter was extracted first by a newly developed lighting device. We use the end gash to identify one of the blades as the reference blade, in order to provide an orientation-invariant method to solve the fishtail image rotation problem. Three invariant features of the blade are used as indicators of quality control. The blade with collapse, whose area is as small as 0.02mm x 0.02mm, could be identified based on the constructed quality control charts. Twenty-five fishtail images are used to validate the proposed AOI system. The successful detection rate of the implemented AOI system is up to 99.2%, and it demonstrates that this system detects the collapse accurately and robustly.
An Advanced Auto-Inspection System for Fishtail Collapse of Micro-router
(2008)
Perng, Der-Baau
;
Chen, Yen-Chung
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
In this paper, an auto-optical inspection system for fishtail collapse of router was proposed. The proposed AOI system first extracts the fishtail image of router by developed mechanism. A method for identifying the center of fishtail was proposed. The I D profile formed by the boundary and center of fishtail is used to segment the fishtail into several blades. We used the end gash to identify one of the blades as the reference blade, so as to provide an orientation-invariant method to solve fishtail image rotation problem. Three invariant features of blade were used as indicators of quality control. The blade with collapse, which area is as small as 0.02 mm x 0.02 mm, could be identified based on the constructed quality control charts. Twenty-five fishtails were used to validate the proposed AOI system. The successful detection rate of the implemented AOI system is up to 99.2% that demonstrated this system achieves the collapse detection accurately and robustly.
An advanced auto-inspection system for micro-router collapse
(2010-10-01)
Perng, Der-Baau
;
Chen, Yen-Chung
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
In this paper, we propose an auto-optical inspection (AOI) system that can inspect micro-router (router) collapse automatically. The router is a tool used to cut a printed circuit board (PCB). A few types of defects could occur in the routers and cause unexpected damage to the PCBs. Among these defects, collapse is the most critical defect that must be detected. Currently, router manufacturing companies rely on human inspectors to control the router quality. We first extract the silhouette edges and associated features (peaks and valleys) of a router's silhouette image by computer vision technique. Then, these silhouette edges and associated features are used to reconstruct a set of 2D isograms that correspond to the router surface. Finally, a pattern recognition method is devised to identify and classify some features of the pattern in the 2D isograms. In this study, two types of routers with different diameters are used for inspection experiments. There are 15 routers of each type. The experimental results reveal that the proposed AOI system can robustly and successfully detect the collapse of diamond-patterned routers with different sizes. The successful detection rate is above 96%. The proposed AOI system can assist in determining the quality of the routers.
An SDN-based Defensive Solution against DHCP Attacks in the Virtualization Environment
(2017-01-01)
Wang, Jhen-Li
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Chen, Yen-Chung
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資訊工程學系
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Department of Computer Science
Network virtualization brings remarkable evolution for networking, and it breaks through the resource boundaries originated from the physical network devices. Software-defined network (SDN), on the other hand, makes operational management more flexible for virtual network. DHCP is one of the most common protocols in the network. However, it becomes unsafe if misused by hackers. In this paper, we develop an SDN-based defensive solution against three kinds of severe DHCP attacks or misconfiguration. Besides, we also launch attacks in our environment to ensure the solution can be practically used.
Dlk1-Dio3 locus-derived lncRNAs perpetuate postmitotic motor neuron cell fate and subtype identity
(2018-10-12)
Yen, Ya-Ping
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Hsieh, Wen-Fu
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Tsai, Ya-Yin
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Lu, Ya-Lin
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Liau, Ee Shan
The mammalian imprinted Dlk1-Dio3 locus produces multiple long non-coding RNAs (lncRNAs) from the maternally inherited allele, including Meg3 (i.e., Gtl2) in the mammalian genome. Although this locus has well-characterized functions in stem cell and tumor contexts, its role during neural development is unknown. By profiling cell types at each stage of embryonic stem cell-derived motor neurons (ESC similar to MNs) that recapitulate spinal cord development, we uncovered that lncRNAs expressed from the Dlk1-Dio3 locus are predominantly and gradually enriched in rostral motor neurons (MNs). Mechanistically, Meg3 and other Dlk1-Dio3 locus-derived lncRNAs facilitate Ezh2/Jarid2 interactions. Loss of these lncRNAs compromises the H3K27me3 landscape, leading to aberrant expression of progenitor and caudal Hox genes in postmitotic MNs. Our data thus illustrate that these lncRNAs in the Dlk1-Dio3 locus, particularly Meg3, play a critical role in maintaining postmitotic MN cell fate by repressing progenitor genes and they shape MN subtype identity by regulating Hox genes.
Phrase Search for Encrypted Cloud Storage
(2018-03-01)
Chen, Yen-Chung
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Wu, Yu-Sung
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Tzeng, Wen-Guey
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資訊工程學系
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Department of Computer Science
With the growth in the popularity of cloud storage service (CSS), the accumulation of private data on the cloud requires the use of data encryption to prevent leakage of sensitive information to untrusted third parties. However, as the amount of data kept on the cloud storage is increasing, the use of data encryption makes it difficult or even impossible to locate the data of interest efficiently and securely. In this paper, we present a framework for CSS to support queries in encrypted form so that the data on cloud storage can be located efficiently and securely. At the core of the framework is a novel indexing structure, called the bloom filter encrypted search tree (BFEST). The BFEST supports queries in the form of phrase keywords. Client-side encryption, using secret keys that are unknown to the cloud service provider, protects the queries and the retrieved data. We implemented a prototype by extending the hicloud S3 [13] CSS with the proposed framework. The experimental results indicate that the framework can ensure query privacy for encrypted data with an acceptable performance overhead in a practical setting.