Browsing by Author "Lin, Yu-Hsiang"

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A 2.37-Gb/s 284.8 mW Rate-Compatible (491,3,6) LDPC-CC Decoder
(2012-04-01)
Chen, Chih-Lung
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Lin, Yu-Hsiang
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Chang, Hsie-Chia
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Lee, Chen-Yi
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電子工程學系及電子研究所
This paper presents a (491,3,6) time-varying low-density parity check convolutional code (LDPC-CC) decoder chip. This work combines the algorithm level, node level, and bit level optimizations to achieve over 2 Gb/s throughput with acceptable hardware cost and power. The algorithm level optimization is the on-demand variable node activation scheduling with concealing channel values, which can not only achieve twice faster decoding convergence speed than log-belief propagation (log-BP) algorithm, but also reduce the 17% message storage capacity. The node level optimization duplicates the check node units and variable node units and unfolds the message storage first-in-first-outs (FIFOs) so that the throughput becomes twelve multiplying with clock frequency. In the meantime, the bit level optimization is employed to retime the critical path such that the higher clock frequency can be achieved and message storage size is slightly reduced. Furthermore, a novel hybrid-partitioned FIFO is proposed to provide sufficient memory bandwidth to processing units and alleviate power consumption. With these schemes, a test chip of proposed LDPC-CC decoder has been fabricated in 90 nm CMOS technology with core area of 2.37 x 1.14 mm(2). Maximum throughput 2.37 Gb/s is measured under 1.2 V supply with energy efficiency of 0.024 nJ/bit/proc. Depending on the operation mode, power can be scaled down to 90.2 mW while maintaining 1.58 Gb/s at 0.8 V supply.
Adopting the Extension of UTAUT Model to Investigate the Determinants of e-book Adoption
(2014-01-01)
Hsu, Chia-Lin
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Chen, Mu-Chen
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Lin, Yu-Hsiang
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Chang, Kuo-Chien
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Hsieh, Ai-Yun
This study aims to examine the key factors affecting users' adoption of e-book by an extension of unified theory of acceptance and use of technology (UTAUT) with environment concern, perceived benefit, and benevolence trust. 343 samples of data were analyzed using a structural equation modeling (SEM). Results showed that user's adoption of e-book is significantly determined by all of the factors.
Asynchronous Power Management Protocols With Minimum Duty Cycle and Maximum Adaptiveness for Multihop Ad Hoc Networks
(2013-09-01)
Chou, Zi-Tsan
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Lin, Yu-Hsiang
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Sheu, Tsang-Ling
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資訊工程學系
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Department of Computer Science
IEEE 802.11 is currently the de facto medium access control (MAC) standard for mobile ad hoc networks (MANETs). However, in a multihop MANET, 802.11 power management may completely fail if stations are out of synchronization. To fix this problem, several papers have proposed various cyclic quorum-based power management (CQPM) protocols, which, however, may also fail if stations have different schedule repetition intervals (SRIs). Hence, adaptive CQPM protocols, namely, adaptive quorum-based energy conserving (AQEC) and hyper quorum system (HQS), were proposed to overcome this drawback. However, the duty cycles of AQEC and HQS are far from optimal. In this paper, we propose the optimal fully adaptive and asynchronous (OFAA) power management protocol for a multihop MANET, which has the following attractive features: 1) By means of factor-hereditary quorum space, the OFAA protocol guarantees that two neighboring stations can discover each other in bounded time, regardless of their clock difference and individual SRIs; 2) given the length of SRI, the duty cycle of a station reaches the theoretical minimum; 3) the number of tunable SRIs of every station reaches the theoretical maximum; 4) the time complexity of OFAA neighbor maintenance is O(1); 5) a cross-layer SRI adjustment scheme is proposed such that a station can adaptively tune the values of SRI to maximize energy conservation according to flow timeliness requirements. Both theoretical analysis and simulation results demonstrate that the OFAA protocol is much more energy efficient than AQEC and HQS protocols.
Information technology adoption for sustainable development: green e-books as an example
(2017-01-01)
Hsu, Chia-Lin
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Chen, Mu-Chen
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Lin, Yu-Hsiang
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
In recent years, due to increasing awareness of the need for environmental protection, there have been significant efforts to improve consumers' acceptance of green information technology(IT) products for sustainable development. This study first investigated how knowledge about a green IT product (e-books) influences consumers' planning processes by using the technology acceptance model and the theory of planned behavior. Data from 320 respondents were analyzed using structural equation modeling to examine the hypothesized relationships in the research model. Results show that perceived usefulness, attitudes, subjective norms, and perceived behavioral control have a significant and positive impact on the intention to purchase e-books. Results also show the moderating effect of consumers' knowledge about the environmental friendliness of e-books on their intention to buy e-books. Finally, important implications of the findings are discussed, and directions for future research are also provided in this paper.
Investigating the determinants of e-book adoption
(2017-01-01)
Hsu, Chia-Lin
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Lin, Yu-Hsiang
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Chen, Mu-Chen
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Chang, Kuo-Chien
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Hsieh, Ai-Yun
Purpose - The purpose of this paper is to examine the key factors that affect users' adoption of e-books using an extension of the unified theory of acceptance and use of technology (UTAUT) that includes the following factors: environmental concerns, perceived benefits, and benevolence trust. Design/methodology/approach - The authors analyzed survey responses from 343 participants using structural equation modeling to examine the hypothesized relationships in this research model. Findings - The results show that users' adoption of e-books is determined by performance expectancy, effort expectancy, social influence, facilitating conditions, environmental concern, perceived benefit, and benevolence trust. Research limitations/implications - The authors restricted this study to consumers' adoption of e-books. Further studies could examine consumer's adoption of other mediums, such as cutting-edge information technologies. Practical implications-The results suggest that marketers should consider altering their methods of promoting e-books to attract consumers and further affect their usage intention. Originality/value - This study proposes and tests an extended UTAUT model that includes the additional factors of environmental concern, perceived benefit, and benevolence trust in order to examine the influence of these factors on e-book adoption. The findings are particularly useful for assisting managers to increase e-book adoption.
Large Structural Shear Deformation and Failure Monitoring Using Bend Losses in Polymer Optical Fibre
(2020-01-01)
Yuen, Terry Y. P.
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Tsai, Cheng-An
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Deb, Trissa
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Lin, Yu-Hsiang
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Nyienyi, June
Rapid identification of structural damage positions is essential to the post-disaster rehabilitation of structures and infrastructures. Large shear deformation, e.g., shear failure of bridge piers, shear-slip of slopes, and shear cracking of structural walls, is often the cause of structural instability. Distributed optical fibre sensing (DOFS) techniques have an advantage over point-based sensors in terms of spatial continuous structural condition monitoring. This paper presents the development of new measurement theory and algorithm to evaluate the structural shear deflection based on the large beam deflection and optical bend loss theories. The proposed technique adopted a photon-counting Optical Time Domain Reflectometer (nu-OTDR) with polymer optical fibres (POFs) which has a large deformation measurement range and high spatial resolution. In the experiment, shear deformation events can be successfully detected and evaluated from the proposed technique. When the normalised shear deformation is larger than 0.2, both the event locations and the magnitudes can be accurately determined. When normalised shear deformation is lesser than 0.2, the error in the magnitude evaluation increased, but the event location can be found with an absolute error <0.5 m. Multiple shear events can be treated as independent events when they are separated by more than 5 m. Various configurations of POFs attached to concrete beam specimens for rupture failure monitoring were also studied. The configuration that could maximise the POF curvature at the beam failure produced the largest nu-OTDR signals. In other configurations in which the POFs were only stretched at failure, the signals were less strong and were influenced by the POF-structure bonding strength.
Optimal and Maximized Configurable Power Saving Protocols for Corona-Based Wireless Sensor Networks
(2015-12-01)
Lin, Yu-Hsiang
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Chou, Zi-Tsan
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Yu, Chun-Wei
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Jan, Rong-Hong
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資訊工程學系
Wireless sensor networks (WSNs) are one of the most important ingredients in the Internet of Things. Thus it is vital to design a good power saving protocol, which operates at the medium access control (MAC) layer, for a WSN since sensors are generally battery-powered. On the other hand, organizing a WSN into coronas centered at the sink is a simple effective technique to achieve low-overhead routing where every sensor needs neither to broadcast beacons nor to maintain routing/neighbor tables. Hence in this paper, we propose an optimal and maximized configurable power saving protocol, named Green-MAC, for a corona-based WSN, which has the following attractive features. (i) By using the generalized Chinese remainder theorem, Green-MAC guarantees that any two sensors in the neighboring coronas can simultaneously wake up in bounded time regardless of their schedule offset as well as their respective cycle lengths. (ii) Given the cycle length, the ATF-ratio (i.e. the fraction of awake time frames in a cycle) of each sensor reaches the theoretical minimum. (iii) Under the minimum ATF-ratio constraints, the number of configurable ATF-ratios of each sensor reaches the theoretical maximum. (iv) An ATF-ratio configuration scheme is proposed for Green-MAC such that the power consumption of a WSN can be minimized while the worst event-to-sink delay requirement can be fulfilled with high probability. Both theoretical analysis and simulation results demonstrate that Green-MAC greatly outperforms existing power saving protocols for corona-based WSNs, including Q-MAC and Queen-MAC, in terms of ATF-ratio, configurability, network lifetime, delay violation ratio, and event-to-sink throughput.
Optimal Asymmetric and Maximized Adaptive Power Management Protocols for Clustered Ad Hoc Wireless Networks
(2011-12-01)
Chou, Zi-Tsan
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Lin, Yu-Hsiang
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Jan, Rong-Hong
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資訊工程學系
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Department of Computer Science
IEEE 802.11 is currently the most popular medium access control (MAC) standard for mobile ad hoc networks (MANETs). On the other hand, clustering in MANETs is a promising technique to ensure the scalability of various communication protocols. Thus, we propose an optimal asymmetric and maximized adaptive power management protocol, called OAMA, for 802.11-based clustered MANETs, which has the following attractive features. 1) Given the length of schedule repetition interval (SRI), the duty cycles of both clusterheads and members reach the theoretical minimum. 2) Under the minimum duty cycle constraints, the numbers of tunable SRIs for clusterheads and members reach the theoretical maximum. 3) By means of factor-correlative coterie-plane product, OAMA guarantees bounded-time neighbor discovery between the clusterhead and its member, and between all clusterheads, regardless of stations' individual SRIs and the schedule offset between neighboring stations. 4) The time complexity of OAMA neighbor maintenance is O(1). 5) OAMA adopts a cross-layer SRI adjustment scheme such that stations can adaptively tune the values of SRI to maximize energy conservation according to flow timeliness requirements. Both theoretical analyses and simulation results show that OAMA substantially outperforms existing power management protocols for clustered MANETs, including AQEC [2] and ACQ [14], in terms of duty cycle, adaptiveness, data delay dropped ratio, network lifetime, and end-to-end energy throughput.
Optimal Fully Adaptive Power Management Protocols for Asynchronous Multi-Hop Ad Hoc Wireless Networks
(2008)
Chou, Zi-Tsan
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Lin, Yu-Hsiang
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Jan, Rong-Hong
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資訊工程學系
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Department of Computer Science
In wireless ad hoc networks, IEEE 802.11 power management may completely fail if power-saving (PS for short) stations are out of synchronization. To fix this problem, [5]-[8] proposed various cyclic quorum-based power management (CQPM) protocols, which, however, may also completely fail if some PS stations have different schedule repetition intervals (SRIs). To conquer all these problems, we propose the OAPM protocol, which has the following attractive features. (i) By means of novel factor-hereditary quorum space techniques, OAPM ensures that two PS neighbors can discover each other in finite time regardless of their clock difference and their individual SRIs. (ii) Given the maximum value of SRI, S-max, the number of tunable SRIs for every PS station is S-max. (iii) The idle duty cycles for all SRIs are minimal. (iv) The time complexity of OAPM neighbor maintenance is constant. (v) A cross-layer SRI adjustment scheme is proposed such that a PS station can adaptively tune its SRI according to traffic QoS requirements. Primary simulation results show that OAPM achieves better energy efficiency than existing CQPM protocols.
Visible light positioning (VLP) system using low-cost organic photovoltaic cell (OPVC) for low illumination environments
(2020-08-31)
Hong, Chong-You
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Wu, Yu-Chun
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Lin, Yu-Hsiang
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Liu, Yang
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Chow, Chi-Wai
We propose and demonstrate a received-signal-strength (RSS) based visible light positioning (VLP) system using a low-cost organic photovoltaic cell (OPVC) receiver (Rx). The OPVC is a passive device without the need of external power supply. It could detect VLC signal and harvest energy. Our developed OPVC has a high power conversion efficiency (PCE) of 9.8%. The VLP system can be operated at a low illumination of 130 lux. The regression machine learning (MIL) algorithm is used to enhance the positioning accuracy. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement