Browsing by Issue Date, starting with "2018-02-01"

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A Novel Method of Electrical Measurement for Stacking Error in 3D/2.5D Integration
(2018-02-01)
Lee, Shih-Wei
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Kuo, Shu-Chiao
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Chen, Kuan-Neng
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
A novel method for the inspection of the stacking misalignment in three-dimensional integration circuit (3DIC) by using electrical measurement is proposed. The metal line pattern designed in this paper combined with bump-less TSV fabrication process can successfully detect the direction and quantity of stacking fault. In addition, circuit combined with testing structure can be developed and simulated by using the current mirror concept and offered measurements with better efficiency.
Deep Unfolding for Topic Models
(2018-02-01)
Chien, Jen-Tzung
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Lee, Chao-Hsi
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電機工程學系
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Department of Electrical and Computer Engineering
Deep unfolding provides an approach to integrate the probabilistic generative models and the deterministic neural networks. Such an approach is benefited by deep representation, easy interpretation, flexible learning and stochastic modeling. This study develops the unsupervised and supervised learning of deep unfolded topic models for document representation and classification. Conventionally, the unsupervised and supervised topic models are inferred via the variational inference algorithm where the model parameters are estimated by maximizing the lower bound of logarithm of marginal likelihood using input documents without and with class labels, respectively. The representation capability or classification accuracy is constrained by the variational lower bound and the tied model parameters across inference procedure. This paper aims to relax these constraints by directly maximizing the end performance criterion and continuously untying the parameters in learning process via deep unfolding inference (DUI). The inference procedure is treated as the layer-wise learning in a deep neural network. The end performance is iteratively improved by using the estimated topic parameters according to the exponentiated updates. Deep learning of topic models is therefore implemented through a back-propagation procedure. Experimental results show the merits of DUI with increasing number of layers compared with variational inference in unsupervised as well as supervised topic models.
FDoF: Enhancing Channel Utilization for 802.11ac
(2018-02-01)
Lin, Chi-Han
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Chen, Yi-Ting
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Lin, Kate Ching-Ju
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Chen, Wen-Tsuen
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資訊工程學系
Multi-user multiple input multiple output (MU-MIMO) enables a multi-antenna access point to serve multiple users simultaneously, and has been adopted as the IEEE 802.11ac standard. While several PHY-MAC designs have recently been proposed to improve the throughput performance of a MU-MIMO WLAN, they, however, usually assume that all the concurrent streams are of roughly equal length. In reality, users usually have frames with heterogeneous lengths even after aggregation, leading to different lengths of a transmission time. Hence, the concurrent transmission opportunities might not always be fully utilized when some streams finish earlier than the others in a transmission opportunity. To resolve this inefficiency, this paper presents full degree-of-freedom (FDoF), a PHY-MAC design that exploits a novel power allocation scheme to reduce the idle channel time and further leverages frame padding to better utilize the spatial multiplexing gain. Unlike traditional MIMO power allocation, which aims at maximizing the theoretical sum-rate, FDoF's power allocation explicitly considers heterogeneous frame lengths and minimizes the channel time required to finish concurrent frames, as a result improving the effective throughput. FDoF's padding protocol then identifies proper users to reuse the remaining idle channel time, while preventing this padding from harming all the ongoing streams. Our evaluation via large-scale trace-driven simulations demonstrates that FDoF's improves the throughput by up to 2.83x, or by 1.36x on average, as compared to the conventional 802.11ac. By combining FDoF's power allocation with frame padding, the average throughput gain can be further increased to 1.75x.
Reconfigurable Hybrid Beamforming for Dual-Polarized mmWave MIMO Channels: Stochastic Channel Modeling and Architectural Adaptation Methods
(2018-02-01)
Wu, Sau-Hsuan
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Chiu, Lin-Kai
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Wang, Jing-Wen
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電機工程學系
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Department of Electrical and Computer Engineering
A reconfigurable hybrid beamforming (HBF) system is presented to dynamically exploit the channel diversities and antenna array directivity in millimeter wave (mmWave) channels. To develop an effective method for HBF architecture adaptation in wideband mmWave channels, the performance of an architecture is evaluated based on its average frequency-domain channel capacity. According to our analysis and simulations, the spatial covariance of the frequency-domain channels of using HBF can still be approximately modeled in a Kronecker form. Furthermore, beamforming directivity and channel spatial diversity have different advantages on capacity improvement in different transceiving conditions. Based on the results of channel modeling, system analysis, and simulations, a reconfigurable HBF architecture is thus proposed to enable flexible adjustments of the active subarrays, the antennas and polarizations of each subarray, and the active analog front-end and radio frequency chains linked to the active subarrays. A training procedure is meanwhile developed for the HBF system to learn proper architectures according to the system constraints, the channel statistics, the baseband precoder structure, and the channel capacity between the transmitter and the receiver. Compared with a fixed HBF system, such a reconfigurable system provides 3-15-dB power gains in channel capacity under various simulated channel conditions.
State-of-the-Art Review on Modal Identification and Damage Detection of Bridges by Moving Test Vehicles
(2018-02-01)
Yang, Y. B.
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Yang, Judy P.
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土木工程學系
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Department of Civil Engineering
In 2004, Yang and co-workers proposed the extraction of bridge frequencies from the dynamic response of a moving test vehicle [Y. B. Yang, C. W. Lin and J. D. Yau, Extracting bridge frequencies from the dynamic response of a passing vehicle, J. Sound Vib. 272 (2004) 471-493] and verified the technique by a field test [C. W. Lin and Y. B. Yang, Use of a passing vehicle to scan the bridge frequencies - An experimental verification, Eng. Struct. 27(13) (2005) 1865-1878]. This technique was extended to construction of mode shapes [Y. B. Yang, Y. C. Li and K. C. Chang, Constructing the mode shapes of a bridge from a passing vehicles: A theoretical study, Smart Struct. Syst. 13(5) (2014) 797-819] and damage identification of bridges. It was referred to as the indirect method for bridge measurement because no vibration sensors are needed for installation on the bridge, but it only requires one or few vibration sensors on the test vehicle. When compared with the conventional direct method that relies fully on the response of the bridge fitted with vibration sensors, the advantage of the indirect method is clear: mobility, economy, and efficiency. Over the past years, many research studies were conducted along the lines of the indirect method for bridge measurement. Significant advances have been made on various aspects of application. This paper represents a state-of-the-art review of the related research works conducted worldwide. Comments and recommendations will be made at proper places, while concluding remarks including future research directions will be presented at the end of the paper.
CWDM DFBLD Transmitter Module for 10-km Interdata Center With Single-Channel 50-Gbit/s PAM-4 and 62-Gbit/s QAM-OFDM
(2018-02-01)
Kao, Hsuan-Yun
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Su, Zhe-Xian
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Shih, Hsiang-Shun
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Chi, Yu-Chieh
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Tsai, Cheng-Ting
Single-channel 50-Gbit/s 4-level pulse amplitude modulation (PAM-4) and 62-Gbit/s orthogonal frequency division multiplexed quadrature amplitude modulation (QAM-OFDM) direct encoding of an uncooled coarse wavelength division multiplexer (CWDM) 100-Gbit/s distributed feedback laser diodes (DF-BLD) transmitter module at 1310-nm transmitter interdata center transmission over 10-km single-mode fiber (SMF) are demonstrated. To enable preleveled 16-QAM OFDM and PAM-4 data transmissions at 62 and 50 Gbit/s, the 1310-nm channel of the DFBLD CWDM transmitter provides modulation bandwidth of 15 GHz, side-mode suppression ratio of 48 dB, and relative intensity noise of -126 dBc/Hz. For encoding the PAM-4 data, the 1310nm channel of the CWDM DFBLD 100-Gbit/s transmitter achieves transmission capacities of 58 and 50 Gbit/s after BtB and 10-km SMF transmissions, respectively. Instead of supporting the back-to-back 16-QAM OFDM with the transmission at 62 Gbit/s with forward error correction (FEC) certified BER of 3.3x10(-3), such a CWDM 100-Gbit/s DFBLD transmitter module can still maintain its highest data rate capacity to indicate a receiving power penalty of 0.35 dB even after 10-km SMF propagation. This is mainly attributed to the selected channel wavelength of the narrow-linewidth DFBLD, which suffers from extremely low chromatic dispersion and RF fading effect.
Effects of statistical sampling errors on flood-damage-reduction project evaluation
(2018-02-01)
Su, H-T
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Tung, Y-K
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防災與水環境研究中心
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Disaster Prevention and Water Environment Research Center
Risk-based decision making of flood-damage-reduction (FDR) projects evaluates different design alternatives that have uncertain inundation-reduction benefits and costs. Uncertainties in FDR projects arise from, but are not limited to, the natural randomness of hydrological events, knowledge deficiency in hydrologic models, and the parameters, among others. This study investigates how the flood damage estimation is affected by the epistemic uncertainty resulting from using finite flood data in defining the flood-frequency relationship and its effects on risk-based decision making. A Monte Carlo simulation is applied in the study to simulate the epistemic uncertainty associated with the sampling error of the flood magnitude. The model parameter uncertainty is explicitly considered in the estimation of statistical features of flood damage. A recently developed decision rule on the basis of expected opportunity loss (EOL) is applied to the risk-based evaluation of the relative merits of several competing flood mitigation projects. EOL-based decision rule has the advantages of considering a decision maker's risk-aversion attitude and incorporating more complete statistical features of project outcomes, including their correlations. The influence of the model parameter uncertainty on the project evaluation results is examined through an example FDR project with five design alternatives in which flood magnitude follows a Gumbel distribution.
Design and Implementation of LTE RRM With Switched LWA Policies
(2018-02-01)
Lin, Yi-Bing
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Shih, Ying-Ju
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Chao, Pei-Wen
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資訊工程學系
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Department of Computer Science
LTE-WLAN aggregation (LWA) combines the radio resources of LTE and WLAN, which takes the advantage of WiFi's high availability and indoor coverage to provide better usage of both WLAN and LTE. In this mechanism, it is essential that the network should intelligently switch a data radio bearer (DRB) to utilize either LTE or Wi-Fi. This paper implements the radio resource management layer (RRM) for LWA and proposes two types of the switched LWA policies: the guaranteed bandwidth and the equal sharing policies. We measure the delay times of the LWA procedures, which indicate that the switched LWA policies can be implemented at the RRM with negligible overhead. We conduct emulation, simulation, and analytic analysis to evaluate the performance of the switched LWA policies. The beauty of the LWA policies is that the performance is not affected by the DRB holding time distribution. Our study indicates that switched LWA can effectively reduce the blocking probability of the LWA's DRBs.
A parametric study on thermal performance of microchannel heat sinks with internally vertical bifurcations in laminar liquid flow
(2018-02-01)
Shen, Han
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Wang, Chi-Chuan
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Xie, Gongnan
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機械工程學系
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Department of Mechanical Engineering
The optimal position of internal vertical bifurcation integrated with a microchannel heat sink (MHS) is investigated numerically in the present research. The corresponding rectangular smooth microchannel is compared with those with internal vertical bifurcation. The optimal position along the streamwise direction for interval distances is studied in detail. The corresponding temperature fields, flow fields, pressure drop and thermal characteristics are presented through verified computational model. The numerical simulation indicates that a clear inflection point of pressure gradient may prevail with the presence of internal vertical bifurcation. It is also found that the microchannel heat sink with a small distance between the tail end of internal vertical bifurcation and the outlet of microchannel shows the best thermal performance instead of those with setting the tail end of internal bifurcation at the outlet of microchannel. The proposed optimal design of internal vertical bifurcation shows improved thermal performance without any pressure drop penalty. (C) 2017 Elsevier Ltd. All rights reserved.
Uneven-Topography-Chip Packing Approach Using Double-Self-Assembly Technology for 3-D Heterogeneous Integration
(2018-02-01)
Shen, Wen-Wei
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Chang, Hsiao-Chun
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Yang, Yu-Tao
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Hu, Yu-Chen
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Chen, Kuan-Neng
Although chip-level heterogeneous integration has high yield for production, low-throughput issue of chip-to-wafer bonding is necessary to be improved. Due to the uneven topography and small chip size, handling issue and alignment accuracy are important factors that impact the difficulty in heterogeneous integration. Self-assembly technology has a high potential to be applied in 3-D heterogeneous integration. By using hydrophobic film to define the stacking area, hydrophilic chips can be assembled to realize alignment process on these areas through wafer surface tension in a very short time. With this concept, double-self-assembly technology is accomplished to resolve both handling and alignment issues for uneven-topography-chip integration. In this paper, different chip sizes of mu-pillar are simulated to investigate the optimal water volume for double-self-assembly process. High alignment accuracy of misalignment measurement can be accomplished with the optimal water volume. Furthermore, microstructure of Cu/In bonded structures and corresponding electrical analyses are evaluated, while various reliability tests are investigated for bonding quality. Excellent results verify that the double-self-assembly technology could be applied to 3-D heterogeneous integration for uneven-topography-chip integration.
Compositional and functional variations of oral microbiota associated with the mutational changes in oral cancer
(2018-02-01)
Yang, Shun-Fa
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Huang, Hsien-Da
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Fan, Wen-Lang
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Jong, Yuh-Jyh
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Chen, Mu-Kuan
Objectives: Both genetic and environmental factors are conceivably required to assess the prognosis of oral squamous cell carcinoma (OSCC), yet little is known regarding the relationship between oral microbiome and the mutational spectrum of OSCC. Materials and methods: Here, we used 16S rRNA amplicon sequencing to study the composition of oral microorganisms in OSCC patients, whose cancer mutational profiles were previously defined by whole-exome sequencing, to evaluate the relationship between oral microbiome and the mutational changes in OSCC. Results: Analyzing the contributions of the five mutational signatures extracted from the primary tumors revealed three groups of OSCC (mutational signature cluster, MSC1-3) that were significantly associated with demographic and clinical features. Taxonomic analysis of the predominant phyla in salivary samples showed variation in the relative abundance of Firmicutes and Bacteroidetes in the three MSC groups. In addition, significant differences in bacterial species richness (alpha diversity) and slight sample-to-sample dissimilarities in bacterial community structures (beta diversity) were noted among different MSC groups. Further, predicting the functional capabilities of microbial communities by reconstruction of unobserved states showed that many pathways related to cell motility were differentially enriched among the three MSC groups. Conclusion: Collectively, these results indicate a potential association of oral microbiome with the mutational changes in OSCC.
Pack Graphs with Subgraphs of Size Three
(2018-02-01)
Chen, Zhen-Chun
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Fu, Hung-Lin
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Huang, Kuo-Ching
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應用數學系
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Department of Applied Mathematics
An H -packing F of a graph G is a set of edge -disjoint subgraphs of G in which each subgraph is isomorphic to H. The leave L or the remainder graph L of a packing F is the subgraph induced by the set of edges of G that does not occur in any subgraph of the packing F. If a leave L contains no edges, or simply L = Phi, then G is said to be H -decomposable, denoted by H broken vertical bar G. In this paper, we prove a conjecture made by Chartrand, Saba and Mynhardt [13]: If G is a graph of size q(G) 0 (mod 3) and delta(G) >= 2, then G is H -decomposable for some graph H of size 3.
Effect of Two-Step Metal Organic Chemical Vapor Deposition Growth on Quality, Diameter and Density of InAs Nanowires on Si (111) Substrate
(2018-02-01)
Yu, Hung Wei
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Anandan, Deepak
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Hsu, Ching Yi
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Hung, Yu Chih
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Su, Chun Jung
High-density (similar to 80/um(2)) vertical InAs nanowires (NWs) with small diameters (similar to 28 nm) were grown on bare Si (111) substrates by means of two-step metal organic chemical vapor deposition. There are two critical factors in the growth process: (1) a critical nucleation temperature for a specific In molar fraction (approximately 1.69 x 10(-5) atm) is the key factor to reduce the size of the nuclei and hence the diameter of the InAs NWs, and (2) a critical V/III ratio during the 2nd step growth will greatly increase the density of the InAs NWs (from 45 mu m(-2) to 80 mu m(-2)) and at the same time keep the diameter small. The high-resolution transmission electron microscopy and selected area diffraction patterns of InAs NWs grown on Si exhibit a Wurtzite structure and no stacking faults. The observed longitudinal optic peaks in the Raman spectra were explained in terms of the small surface charge region width due to the small NW diameter and the increase of the free electron concentration, which was consistent with the TCAD program simulation of small diameter (< 40 nm) InAs NWs.
Projecting adjectives in Chinese
(2018-02-01)
Liu, Chen-Sheng Luther
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外國語文學系
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Department of Foreign Languages and Literatures
Chinese has the comparative morpheme and the positive morpheme, both of which project in syntax. The covert comparative morpheme is the covert allomorph of the comparative morpheme bCjiA o 'more'. The covert bCjiA o 'more' can only occur in a comparative construction where an overt standard of comparison is syntactically available, but the overt one occurs in a comparative construction where an overt standard of comparison is syntactically unavailable. The positive morpheme also has two allomorphs. One is the unstressed hn 'HEN' and the other is its covert counterpart. The covert one can only occur in a focus sensitive domain where the bare gradable adjective is focus-anchored, but the overt one occurs elsewhere. The covert allomorph, regardless of whether it is the comparative or the positive morpheme, is used to avoid violating the Constraint on Multiple Foci. Accordingly, the proposal of the comparative morpheme and the proposal of the positive morpheme can reinforce each other by establishing a theoretical relationship through the Nonhead Stress rule and the Constraint on Multiple Foci.
"Freezing" of NaClO3 Metastable Crystalline State by Optical Trapping in Unsaturated Microdroplet
(2018-02-01)
Niinomi, Hiromasa
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Sugiyama, Teruki
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Miyamoto, Katsuhiko
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Omatsu, Takashige
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應用化學系
We reversibly controlled phase conversion between a microdroplet of a NaClO3 unsaturated aqueous solution and a metastable single crystal, which is usually a short-lived phase in spontaneous crystallization, simply by irradiating a tightly focused visible continuous-wave (CW) laser to the microdroplet. The laser irradiation allowed the metastable crystal to generate and stably grow without a polymorphic transformation. This successful metastable phase control is attributed to the combination of the advantage of optical trapping-induced nucleation that nucleation takes place from unsaturated mother solution and the advantage of microdroplet method, which suppresses additional nucleation leading to the transformation. In situ observation shows the crystal dissolves when the laser irradiation is stopped, whereas the laser irradiation stabilizes the crystal even if the size of the crystal becomes larger than that of focal spot. These observations indicate that a change in the relative magnitudes of chemical potentials between solution/crystalline phases. This change is possibly promoted via crystal growth by trapping of crystalline clusters in optical potential well formed on a crystal surfaces originating from "light propagation" through the crystal. Our results shed a light not only on polymorph control but also on a method to prepare a longer-lived achiral precursor for analysis on achiral chiral transition by "freezing" a kinetic pathway of chiral crystallization.
Novel physical chemistry approaches in biophysical researches with advanced application of lasers: Detection and manipulation
(2018-02-01)
Iwata, Koichi
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Terazima, Masahide
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Masuhara, Hiroshi
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應用化學系
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Department of Applied Chemistry
Novel methodologies utilizing pulsed or intense CW irradiation obtained from lasers have a major impact on biological sciences. In this article, recent development in biophysical researches fully utilizing the laser irradiation is described for three topics, time-resolved fluorescence spectroscopy, time-resolved thermodynamics, and manipulation of the biological assemblies by intense laser irradiation. First, experimental techniques for time-resolved fluorescence spectroscopy are concisely explained in Section 2. As an example of the recent application of time-resolved fluorescence spectroscopy to biological systems, evaluation of the viscosity of lipid bilayer membranes is described. The results of the spectroscopic experiments strongly suggest the presence of heterogeneous membrane structure with two different viscosity values in liposomes formed by a single phospholipid. Section 3 covers the time-resolved thermodynamics. Thermodynamical properties are important to characterize biomolecules. However, measurement of these quantities for short-lived intermediate species has been impossible by traditional thermodynamical techniques. Recently, development of a spectroscopic method based on the transient grating method enables us to measure these quantities and also to elucidate reaction kinetics which cannot be detected by other spectroscopic methods. The principle of the measurements and applications to some protein reactions are reviewed. Manipulation and fabrication of supramolecues, amino acids, proteins, and living cells by intense laser irradiation are described in Section 4. Unconventional assembly, crystallization and growth, amyloid fibril formation, and living cell manipulation are achieved by CW laser trapping and femtosecond laser-induced cavitation bubbling. Their spatio-temporal controllability is opening a new avenue in the relevant molecular and bioscience research fields. This article is part of a Special Issue entitled "Biophysical Exploration of Dynamical Ordering of Biomolecular Systems" edited by Dr. Koichi Kato.
Boosting and Localizing Near-Field in Plasmonic Mirror-Image Nanoepsilon
(2018-02-01)
Lin, Jia-Yu
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Lee, Po-Tsung
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光電工程學系
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Department of Photonics
A novel plasmonic mirror-image nanoepsilon (MINE) structure is studied to achieve significantly enhanced and localized near-field. It is well-known that the nanorod dimer is able to gain a high local field at the center of the structure by adjusting its rod width, rod length, and gap distance. When adopting an auxiliary nanoring structure electron reservoirs surrounding the nanorod-dimer to form the MINE structure, the local field can be further enhanced owing to a large amount of charges into sharp dimer structure which can confine the accumulation of charges to apexes. Thus, better synergistic interaction of gap effect and lightning-rod effect can be achieved for high field enhancement around nanoscale gap. The symmetric mode in the MINE structure enables strong near-field with a concentrated distribution around the gap. The influences of rod-tip angle and gap distance on the optical properties of plasmonic MINE structures are numerically investigated. With reducing the rod-tip angle and gap distance, considerable enhancements on the field intensities at the rod tips and the gap center can be attributed to the improved lightning-rod and gap effects. The near-field intensities at the rod tip and gap center are dramatically enlarged similar to 1.94 x 10(4) and similar to 1.41 x 10(4) times with the rod-tip angle of 41 degrees and gap distance of 10 nm, and the near-field is localized within an extremely small range. These features are very beneficial for various plasmonic applications.
Accurate Classification of Diminutive Colorectal Polyps Using Computer-Aided Analysis
(2018-02-01)
Chen, Peng-Jen
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Lin, Meng-Chiung
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Lai, Mei-Ju
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Lin, Jung-Chun
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Lu, Henry Horng-Shing
BACKGROUND & AIMS: Narrow-band imaging is an image-enhanced form of endoscopy used to observed microstructures and capillaries of the mucosal epithelium which allows for real-time prediction of histologic features of colorectal polyps. However, narrow-band imaging expertise is required to differentiate hyperplastic from neoplastic polyps with high levels of accuracy. We developed and tested a system of computer-aided diagnosis with a deep neural network (DNN-CAD) to analyze narrow-band images of diminutive colorectal polyps. METHODS: We collected 1476 images of neoplastic polyps and 681 images of hyperplastic polyps, obtained from the picture archiving and communications system database in a tertiary hospital in Taiwan. Histologic findings from the polyps were also collected and used as the reference standard. The images and data were used to train the DNN. A test set of images (96 hyperplastic and 188 neoplastic polyps, smaller than 5 mm), obtained from patients who underwent colonoscopies from March 2017 through August 2017, was then used to test the diagnostic ability of the DNN-CAD vs endoscopists (2 expert and 4 novice), who were asked to classify the images of the test set as neoplastic or hyperplastic. Their classifications were compared with findings from histologic analysis. The primary outcome measures were diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic time. The accuracy, sensitivity, specificity, PPV, NPV, and diagnostic time were compared among DNN-CAD, the novice endoscopists, and the expert endoscopists. The study was designed to detect a difference of 10% in accuracy by a 2-sided McNemar test. RESULTS: In the test set, the DNN-CAD identified neoplastic or hyperplastic polyps with 96.3% sensitivity, 78.1% specificity, a PPV of 89.6%, and a NPV of 91.5%. Fewer than half of the novice endoscopists classified polyps with a NPV of 90% (their NPVs ranged from 73.9% to 84.0%). DNN-CAD classified polyps as neoplastic or hyperplastic in 0.45 +/- 0.07 seconds-shorter than the time required by experts (1.54 +/- 1.30 seconds) and nonexperts (1.77 +/- 1.37 seconds) (both P < .001). DNN-CAD classified polyps with perfect intra-observer agreement (kappa score of 1). There was a low level of intra-observer and inter-observer agreement in classification among endoscopists. CONCLUSIONS: We developed a system called DNN-CAD to identify neoplastic or hyperplastic colorectal polyps less than 5 mm. The system classified polyps with a PPV of 89.6%, and a NPV of 91.5%, and in a shorter time than endoscopists. This deep-learning model has potential for not only endoscopic image recognition but for other forms of medical image analysis, including sonography, computed tomography, and magnetic resonance images.
Crosstalk Between Single-Photon Avalanche Diodes in a 0.18-mu m High-Voltage CMOS Process
(2018-02-01)
Wu, Dai-Rong
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Tsai, Chia-Ming
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Huang, Yi-Hsiang
;
Lin, Sheng-Di
;
電子工程學系及電子研究所
Crosstalk between single-photon avalanche diodes (SPADs) fabricated by the standard CMOS process is extensively investigated. The dependence of device structure, device-to-device distance, and bias voltage on crosstalk has been experimentally studied. Our work reveals that direct-path optical crosstalk dominates in these CMOS SPADs, which is also confirmed with the first time-correlated crosstalk measurement. This work is valuable for SPAD array design and optimization in CMOS technology.
Fracture of cobalt chrome, fully-coat beaded femoral revision long stem, a clinical outcomes study
(2018-02-01)
Chang, Chih-Hsiang
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Lin, Po-Chun
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Shih, Cheng-Min
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Chen, Chun-Chieh
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Hsieh, Pang-Hsin
Background: Femoral bone loss during revision total hip arthroplasty poses a challenging problem. Bypass fixation over the diaphysis has achieved clinical success in cases of proximal femoral bone loss. Fracture of cementless, fully bead-coated femoral stem is an uncommon complication. The purpose of this study is to analyze the patients with and without fracture stem and find out the possible risk factors. Methods: From 2006 to 2012, a total of 251 revision long stems (Zimmer, Warsaw, IN) were implanted. In the same period, 17 broken stems that underwent treatment were included for analysis. Patients' demographic data, pattern of femoral bone loss, stem size, medial calcar support in the proximal region of the stem, and the timing of stem breakage were collected and analyzed. Results: The stem size in patients with a broken stem was smaller (p < 0.001), and medial calcar defect was 12.4% and 100% (p < 0.001), respectively. The bone defect was greater in broken group (p = 0.024). The mean duration between revision surgery and stem breakage was 58.07 +/- 36.98 months. Smaller stem size, greater bone defect, and inadequate medial calcar bone support were major risk factors for stem breakage. Conclusions: Bypass fixation in the distal diaphysis with a long stem prosthesis without adequate bone support over medial calcar area may cause stress concentration in the long stem and a fatigue fracture. Use of a smaller prosthesis is the major risk of stem broken. It is essential to repair the proximal femoral bone deficiency and implant selection for better metaphyseal engagement to prevent further stem complications.