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Yu-Liang Chen

Bio: Yu-Liang Chen is an academic researcher from National Taiwan University. The author has contributed to research in topics: Die (integrated circuit) & Quenching (fluorescence). The author has an hindex of 5, co-authored 9 publications receiving 94 citations.

Papers
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Journal ArticleDOI
Szu-Chi Chen1, C.Z. Tsai, Enboa Wu1, I.G. Shih1, Yu-Liang Chen1 
TL;DR: In this paper, the authors identified the weak regions, in terms of mechanical strength, in chips in a semiconductor wafer using the three-point bending test, which was observed in two sectors approximately 45/spl deg/m wide, axisymmetric to the wafer center.
Abstract: Die cracking is an annoying problem in the packaging industry. In this paper, we identified the weak regions, in terms of mechanical strength, in chips in a semiconductor wafer using the three-point bending test. The weak regions were observed in two sectors approximately 45/spl deg/ wide, axisymmetric to the wafer center. The strength of the chips within these weak regions was about 30%-35% lower than the average chip strength of the whole wafer. The existence of these weak regions was related to spiral grinding marks, which, in turn, were formed by backside mechanical grinding. The probability distributions of the chip strength and the chip fragmentary pattern confirmed this relationship. When wafers were mechanically ground until they were 50-/spl mu/m thick, chip warpage was found to be oriented to the direction of the grinding marks. Meanwhile, by slowing the mechanical grinding speed by 50%, we were able to increase the average chip strength by 56%. Either plasma etching or polishing after mechanical grinding eliminated the weak regions, and the optimal amount of mechanical grinding and the polishing depths were observed, beyond which the chip strength would not increase. On the other hand, a preprocess for blunting a new saw blade for chip dicing was found to be essential as the chip strength increased five-fold, whereas increasing the dicing speed or using dual saw instead of a single saw had only small effects on the chip strength degradation.

31 citations

Journal ArticleDOI
TL;DR: In this paper, a dynamic fluorescence image index system capable of non-destructive assessment of water stress in cabbage seedlings was developed, where the quenching curves of chlorophyll fluorescence characteristic to the plant's water stress status under reduced excitation energy were acquired via a multispectral imaging system.

29 citations

Proceedings ArticleDOI
01 Jan 2008
TL;DR: In this paper, a multi-functional remote sensing system (MFRSS) integrating RFID technology with remote spectral imaging and environmental sensing was developed to enhance seedling production and management in greenhouse.
Abstract: A multi-functional remote sensing system (MFRSS) integrating Radio Frequency Identification (RFID) technology with remote spectral imaging and environmental sensing was developed to enhance seedling production and management in greenhouse. Consisted of a management traceability system (also known as management resume) and an environment traceability system (also known as environment resume), a traceable production management system is highly desirable for automated operations in greenhouse. This study is the first application of RFID to an automatic greenhouse seedling production system. The advantages of the MFRSS system are twofold: First, the production management information can be made traceable by establishing passive RFID on the multi-functional remote sensing system during variable boom cruising in the greenhouse. The spectral images were acquired using a color camera and a monochrome camera with a 780 nm optical filter, with the exposure time and signal gain controlled through an IEEE-1394 interface. Secondly, an automatic exposure algorithm eliminating interferences caused by sunlight variation was developed using Matlab 6.5 and LabVIEW 7.1. The tray position data were transferred to the look up table and delivered to the water management module through a DataSocket server and wireless network. The environment-sensing sub-system, including temperature, relative humidity, and photo-quantum measurements, was developed with a PCI-6023 interface to analyze their spatial distribution in the greenhouse. Not only does the mechanism established in the present study provide a basis for developing an automatic seedling production system, the environmental factors and facility status captured by the RFID-integrated MFRSS also enable a traceable seedling production management database, which is a crucial constituent for practical applications.

15 citations

Journal ArticleDOI
TL;DR: This study demonstrated low ethanol-gasoline blended fuels could be used in motorcycle carburetor engines without any modification to keep engine power while reducing exhaust pollutants.
Abstract: In view of energy shortage and air pollution, ethanol-gasoline blended fuel used for motorcycle engine was studied in this work. The emissions of carbon monoxide (CO), nitrogen oxides (NOX) and engine performance of a 125 cc four-stroke motorcycle engine with original carburetor using ethanol-gasoline fuels were investigated. The model of three-variable Box Behnken design (BBD) was used for experimental design, the ethanol blend ratios were prepared at 0, 10, 20 vol%; the speeds of motorcycle were selected as 30, 45, 60 km/h; and the throttle positions were set at 30, 60, 90 %. Both engine performance and air pollutant emissions were then analyzed by response surface method (RSM) to yield optimum operation parameters for tolerable pollutant emissions and maximum engine performance. The RSM optimization analysis indicated that the most suitable ethanol-gasoline blended ratio was found at the range of 3.92–4.12 vol% to yield a comparable fuel conversion efficiency, while considerable reductions of exhaust p...

14 citations

Journal ArticleDOI
TL;DR: In this paper, an automation system based on multi-spectral imaging and mobile environmental factor sensing has been developed and operated to obtain necessary spectral image information of seedling growth status on greenhouse benches, a series of image processing procedures was developed.
Abstract: More and more crops are grown in greenhouses, and crop growth status monitoring is equally important as field-grown crops. An automation system based-on multi-spectral imaging and mobile environmental factor sensing has been developed and operated. To obtain necessary spectral image information of seedling growth status on greenhouse benches, a series of image processing procedures was developed. The study also explored the applications of the radio frequency identification (RFID) system to construct a traceability system for seedling production in greenhouse. Days of seedlings growth can be calculated estimating the PLAI of the plant-oriented multi-spectral images with R2 = 0.989. Appropriate irrigation level could be estimated using different indices with environmental factors. Greenhouse cultivation is a site-specific management illustrated by precision integration.

11 citations


Cited by
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Journal ArticleDOI
16 Jun 2009-Sensors
TL;DR: The paper focuses on WSN (Wireless Sensor Networks) and RFID (Radio Frequency Identification), presenting the different systems available, recent developments and examples of applications, including ZigBee based WSN and passive, semi-passive and active RFID.
Abstract: The aim of the present paper is to review the technical and scientific state of the art of wireless sensor technologies and standards for wireless communications in the Agri-Food sector. These technologies are very promising in several fields such as environmental monitoring, precision agriculture, cold chain control or traceability. The paper focuses on WSN (Wireless Sensor Networks) and RFID (Radio Frequency Identification), presenting the different systems available, recent developments and examples of applications, including ZigBee based WSN and passive, semi-passive and active RFID. Future trends of wireless communications in agriculture and food industry are also discussed.

662 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present a comprehensive view of current applications and new possibilities of RFID, but also explain the limitations and challenges of this technology, including the operation in harsh environments, with dirt, extreme temperatures; the huge volume of data that are difficult to manage; the need of longer reading ranges, due to the reduction of signal strength due to propagation in crop canopy; the behavior of different frequencies, understanding what is the right one for each application; the diversity of the standards and the level of granularity are some of them.

296 citations

Journal ArticleDOI
TL;DR: In this paper, a review of non-invasive techniques for quality analysis and inspection of specialty crops, mainly fresh fruits and vegetables, over the past decade up to the year 2010 is presented.

214 citations

Journal ArticleDOI
08 Dec 2010-Sensors
TL;DR: It could be expected that the use of such a system could contribute to increasing crop yields and improving quality in the agricultural field by supporting the decision making of crop producers through analysis of the collected information.
Abstract: This paper proposes an agricultural environment monitoring server system for monitoring information concerning an outdoors agricultural production environment utilizing Wireless Sensor Network (WSN) technology. The proposed agricultural environment monitoring server system collects environmental and soil information on the outdoors through WSN-based environmental and soil sensors, collects image information through CCTVs, and collects location information using GPS modules. This collected information is converted into a database through the agricultural environment monitoring server consisting of a sensor manager, which manages information collected from the WSN sensors, an image information manager, which manages image information collected from CCTVs, and a GPS manager, which processes location information of the agricultural environment monitoring server system, and provides it to producers. In addition, a solar cell-based power supply is implemented for the server system so that it could be used in agricultural environments with insufficient power infrastructure. This agricultural environment monitoring server system could even monitor the environmental information on the outdoors remotely, and it could be expected that the use of such a system could contribute to increasing crop yields and improving quality in the agricultural field by supporting the decision making of crop producers through analysis of the collected information.

162 citations

Journal ArticleDOI
TL;DR: It was demonstrated from the review that most of the research yield favourable results of engine modelling prediction for both of the methods, and a high degree of determination coefficient indicating that the model could predict the model efficiency with reasonable accuracy.
Abstract: Alternative fuel is one of the widely used fuel substitutions for both petrol and diesel in the field of internal combustion engine. The increase in the demand for alternative fuel is currently driven by the requirement of decreasing engine fuel consumption and fulfilling the stringent engine exhaust emissions pollutant regulations. In order to effectively tackle the aforementioned concerns, it appears that through engine experimental analysis alone for both engine performance and exhaust emissions is insufficient. Recently, the need for engine modelling based on statistical and machine learning methodologies through response surface and artificial neural network technique, respectively, are non-trivial to provide a better decision support analysis. Therefore, the present study reviews the extent to which the application of these methods in various alternative fuel in both spark and compression ignition engine to investigate their viability. The paper also describes herein the ways to determine the accuracy and the significance of model fitting for both methodologies. It was demonstrated from the review that most of the research yield favourable results of engine modelling prediction for both of the methods. It can be concluded the comparison between predicted and experimental results provided a high degree of determination coefficient indicating that the model could predict the model efficiency with reasonable accuracy.

128 citations