Copper Metal for Semiconductor Interconnects

Resistance-capacitance (RC) delay produced by the interconnects limits the speed of the integrated circuits from 0.25 mm technology node. Copper (Cu) had been used to replace aluminum (Al) as an interconnecting conductor in order to reduce the resistance. In this chapter, the deposition method of Cu films and the interconnect fabrication with Cu metallization are introduced. The resulting integration and reliability challenges are addressed as well

ICT Integrated in Higher Education: The Activities, Context and Effects

Accompanying with the development and advancement of ICT integrated in higher education, it enabled the progressive changes in centered pedagogies and practices. This study attempts to explore the context in ICT integrated education with student perspective and to propose a research model combining with readiness and activity theory to exam the effects of ICT integrated in higher education and the learning performance. 603 questionnaires were collected from the universities in Taiwan and analyzed with AMOS. The results indicate that informational-based readiness has positive effect on user’s readiness, user’s readiness and schools’ ICT support both have positive effects on ICT actual use, and ICT actual use also has positive effect on their perceived satisfaction (performance). The findings could enrich the research of ICT integrated education with different perspectives, and would be helpful to extend to the long-term development in academics and practical ICT application

Using a microfluidic device for 1 μl DNA microarray hybridization in 500 s

This work describes a novel and simple modification of the current microarray format. It reduces the sample/reagent volume to 1 μl and the hybridization time to 500 s. Both 20mer and 80mer oligonucleotide probes and singly labeled 20mer and 80mer targets, representative of the T-cell acute lymphocytic leukemia 1 (TAL1) gene, have been used to elucidate the performance of this hybridization approach. In this format, called shuttle hybridization, a conventional flat glass DNA microarray is integrated with a PMMA microfluidic chip to reduce the sample and reagent consumption to 1/100 of that associated with the conventional format. A serpentine microtrench is designed and fabricated on a PMMA chip using a widely available CO(2) laser scriber. The trench spacing is compatible with the inter-spot distance in standard microarrays. The microtrench chip and microarray chip are easily aligned and assembled manually so that the microarray is integrated with a microfluidic channel. Discrete sample plugs are employed in the microchannel for hybridization. Flowing through the microchannel with alternating depths and widths scrambles continuous sample plug into discrete short plugs. These plugs are shuttled back and forth along the channel, sweeping over microarray probes while re-circulation mixing occurs inside the plugs. Integrating the microarrays into the microfluidic channel reduces the DNA–DNA hybridization time from 18 h to 500 s. Additionally, the enhancement of DNA hybridization reaction by the microfluidic device is investigated by determining the coefficient of variation (CV), the growth rate of the hybridization signal and the ability to discriminate single-base mismatch. Detection limit of 19 amol was obtained for shuttle hybridization. A 1 μl target was used to hybridize with an array that can hold 5000 probes

ATACgraph: Profiling genome-wide chromatin accessibility from ATAC-seq

Assay for transposase-accessible chromatin using sequencing data (ATAC-seq) is an efficient and precise method for revealing chromatin accessibility across the genome. Most of the current ATAC-seq tools follow chromatin immunoprecipitation sequencing (ChIP-seq) strategies that do not consider ATAC-seq-specific properties. To incorporate specific ATAC-seq quality control and the underlying biology of chromatin accessibility, we developed a bioinformatics software named ATACgraph for analyzing and visualizing ATAC-seq data. ATACgraph profiles accessible chromatin regions and provides ATAC-seq-specific information including definitions of nucleosome-free regions (NFRs) and nucleosome-occupied regions. ATACgraph also allows identification of differentially accessible regions between two ATAC-seq datasets. ATACgraph incorporates the docker image with the Galaxy platform to provide an intuitive user experience via the graphical interface. Without tedious installation processes on a local machine or cloud, users can analyze data through activated websites using pre-designed workflows or customized pipelines composed of ATACgraph modules. Overall, ATACgraph is an effective tool designed for ATAC-seq for biologists with minimal bioinformatics knowledge to analyze chromatin accessibility. ATACgraph can be run on any ATAC-seq data with no limit to specific genomes. As validation, we demonstrated ATACgraph on human genome to showcase its functions for ATAC-seq interpretation. This software is publicly accessible and can be downloaded at https://github.com/RitataLU/ATACgraph

Joint QoS-Aware Scheduling and Precoding for Massive MIMO Systems via Deep Reinforcement Learning

The rapid development of mobile networks proliferates the demands of high data rate, low latency, and high-reliability applications for the fifth-generation (5G) and beyond (B5G) mobile networks. Concurrently, the massive multiple-input-multiple-output (MIMO) technology is essential to realize the vision and requires coordination with resource management functions for high user experiences. Though conventional cross-layer adaptation algorithms have been developed to schedule and allocate network resources, the complexity of resulting rules is high with diverse quality of service (QoS) requirements and B5G features. In this work, we consider a joint user scheduling, antenna allocation, and precoding problem in a massive MIMO system. Instead of directly assigning resources, such as the number of antennas, the allocation process is transformed into a deep reinforcement learning (DRL) based dynamic algorithm selection problem for efficient Markov decision process (MDP) modeling and policy training. Specifically, the proposed utility function integrates QoS requirements and constraints toward a long-term system-wide objective that matches the MDP return. The componentized action structure with action embedding further incorporates the resource management process into the model. Simulations show 7.2% and 12.5% more satisfied users against static algorithm selection and related works under demanding scenarios

Using optical code-division multiple-access techniques in Michelson interferometer vibration sensor networks

This study proposes a spectral-amplitude-coding optical code-division multiple-access (SAC-OCDMA) framework for accessing the vibration frequency of a test object by using a Michelson interferometer vibration sensor (MIVS). Each sensor node possesses an individual signature codeword, and liquid crystal spatial light modulator (LC-SLM) encoders/decoders (codecs) are adopted to provide excellent orthogonal properties in the frequency domain. The proposed LC-SLM-based OCDMA system mitigates multiple access interference among all sensor nodes. When optical beams strike and are reflected by the object, the sensing interferometer becomes sensitive to external physical parameters such as temperature, strain, and vibration. The MIVS includes a Michelson interferometer placed at a specific distance from the test object on a designed vibration platform. A balanced photodetector (BPD) was used to convert the light output of the LC-SLM decoders into electrical signals, and a digitizing oscilloscope was used to Fourier transform the BPD electrical signal output, thereby yielding the vibration frequency of the test object. The results showed that the proposed sensor network with an interferometer can be used as a distributed highly sensitive sensor to obtain mechanical values. This study provides a new optical sensor network for current vibration frequency measurements

Bridge scour evaluation based on ambient vibration

The vulnerability of bridges to hazards such as earthquakes, wind and floods necessitates special structural characteristics. To guarantee the stability of bridge structures, the precise evaluation of the scour depth of bridge foundation has recently become an important issue, as most of the unexpected damage to or collapse of bridges has been attributed to hydraulic issues. In this paper, a vibration-based bridge health monitoring system that utilizes only the response of superstructure to rapidly evaluate the embedded depth of a bridge column is proposed. To clarify the complex fluid-solid coupling phenomenon, the effects of embedded depth and water level were first verified through a series of static experiments. A confined finite element model simulated by soil spring effects was then established to illustrate the relationship between the fundamental frequency and the embedded depth. Using the proposed algorithm, the health of the bridge is able to be inferred by processing the ambient vibration response of the superstructure. To implement the proposed algorithm, a SHM prototype system monitoring environmental factors such as temperature, water level, and inclination was developed to support on-line processing. The performance of the proposed system was verified by a series of dynamic bridge scour experiments conducted in a laboratory flume and compared with readings from a water-proof camera. The results showed that using the proposed vibration-based bridge health monitoring system, the embedded depth of bridge column during complex scour processes is able to be reliably calculated

Accuracy of hysteroscopic biopsy, compared to dilation and curettage, as a predictor of final pathology in patients with endometrial cancer

AbstractObjectiveTo compare the methods of transcervical resectoscopy versus dilation and curettage (D&C) for endometrial biopsy and to compare these methods for the percentage of histological upgrades at the final posthysterectomy pathology findings in endometrial cancer.Materials and methodsWe retrospectively reviewed 253 cases of uterine cancer diagnosed from May 1995 to January 2014. Included in the study were patients who received transcervical resectoscopy (TCR) or D&C biopsy as the diagnostic method and underwent laparoscopic staging at our institution. The International Federation of Gynecologists and Obstetricians (FIGO) grade in the pathological report of the biopsy and final hysterectomy were recorded. The extrauterine risk was stratified using the initial FIGO grade and depth of myometrium invasion. It was compared to the actual risk using final pathological findings.ResultsWe identified 203 cases of endometrial cancer; 18 (8.9%) patients had a higher histological grade at the final hysterectomy. Among the 203 patients, 76 patients underwent TCR biopsy and 127 underwent D&C biopsy. The histological grade was upgraded in two (2.6%) patients in the TCR group. Three (3.9%) patients had positive peritoneal washings. In the D&C group, 16 (12.6%) patients with three (2.4%) positive peritoneal washings were upgraded.ConclusionTranscervical resectoscopy could provide more precise grading information, compared to D&C (2.6% vs. 12.6%). Doctors could therefore make a more accurate staging plan, based on the preoperative risk evaluation