Pair Of Modules Research Articles

Optical isolation using microring modulators

Optical isolators, while commonplace in bulk and fiber optical systems, remain a key missing component in integrated photonics. Isolation using magneto-optic materials has been difficult to integrate into complementary metal–oxide–semiconductor (CMOS) fabrication platforms, motivating the use of other paths to effective non-reciprocity such as temporal modulation. We demonstrate a non-reciprocal element comprising a pair of microring modulators and a microring phase shifter in an active silicon photonic process, which, in combination with standard bandpass filters, yields an isolator on-chip. Isolation up to 13 dB is measured with a 3 dB bandwidth of 2 GHz and insertion loss of 18 dB. We also show transmission of a 4 Gbps optical data signal through the isolator while retaining a wide-open eye diagram. This compact design, in combination with increased modulation efficiency, could enable modulator-based isolators to become a standard ‘black-box’ component in integrated photonics CMOS foundry platform component libraries.

Dynamic Free-Spectral-Range Measurement for Fiber Resonator Based on Digital-Heterodyne Optical Phase-Locked Loop

We propose a novel scheme, based on digital-heterodyne optical phase-locked loop with whole-fiber circuit, to dynamically measure the free-spectral-range of a fiber resonator. The optical phase-locked loop is established with a differential frequency-modulation module consists of a pair of acousto-optic modulators. The resonance-tracking loop is derived with the Pound-Drever-Hall technique for locking the heterodyne frequency of the OPLL on the frequency difference between adjacent resonance modes. A stable locking accuracy of about 7 × 10?9 and a dynamic locking accuracy of about 5 × 10?8 are achieved with the FSR of 8.155 MHz, indicating a bias stability of the resonator fiber optic gyro of about 0.1?/h with 10 Hz bandwidth. In addition, the thermal drift coefficient of the FSR is measured as 0.1 Hz/?C. This shows remarkable potential for realizing advanced optical measurement systems, such as the resonant fiber optic gyro, and so on.

Modulation Classification Based on Fourth-Order Cumulants of Superposed Signal in NOMA Systems

In this paper, we study the automatic modulation classification in a non-orthogonal multiple access system. To mitigate the effect of interference, a likelihood-based algorithm and a fourth-order cumulant-based algorithm are proposed. Different from the maximum likelihood classifier for a single signal without interference, a likelihood function of the far and near users' signals is derived. Then, a marginal probability for the far user is obtained by using the Bayesian formula. Hence, the modulation type can be determined by maximizing the marginal probability. The high computational complexity of the likelihood-based algorithm renders it impractical; accordingly, it serves as a theoretical performance bound. On the other hand, we construct a feature vector through the estimated fourth-order cumulants of the received signal including the superposed signal and noise. For each modulation pair, using the mean and covariance matrix of the estimated feature vector, its probability density function can be obtained. Then, the key is to calculate the mean and covariance matrix of the estimated feature vector. To solve this problem, the moments of the superposed signal are derived. Therefore, modulation classification can be performed by maximizing the probability density function. Extensive simulations verify that the two proposed algorithms perform well under a wide range of signal-to-noise ratios and observation lengths.

Блочный принцип построения и оценки снижения ЭПР непоглощающих широкополосных 2-битных анизотропных цифровых метапокрытий.

The block principle of constructing of coding matrices for non-absorbing flat digital anisotropic meta-coatings (MC) used to reduce monostatic RCS of objects is considered. The essence of this principle consists in 2-bit coding of the tilt angles of the anisotropy axes of the MC modules so that four arbitrary adjacent modules of the MC form two pairs of antiphase modules. The use of the block principle in the development of a MC provides a reduction of monostatic RCSs on cross polarization due to cancellation of interference waves. The reduction of the monostatic RCS of a MC at matched polarization (co-RCS) is due to the twist-effect. Simultaneously with cancellation and twist-effect, diffuse wave scattering is implemented in the developed digital MCs. The proposed 2-bit anisotropic MCs make it possible to achieve a more effective reduction of monostatic co-RCS (in relation to the traditionally accepted level of minus 10 dB) in a wide frequency band, for different polarization planes of the incident wave. The impedance and full-wave models of the two main blocks of digital anisotropic MCs are developed. An asymptotic representation of the polarization scattering matrix is obtained for the impedance model of the MC block using the method of physical optics. The algorithm for calculating the frequency characteristics (FC) of monostatic co-RCS of impedance models of MC blocks is implemented in the Octave program. Full-wave models of MC blocks are built using the HFSS program. Layouts of two main MC blocks were made. Monostatic co-RCSs of the blocks are measured in the 7÷17.5 GHz frequency band for different polarizations of the incident wave. It is shown that the calculated and measured frequency characteristics of monostatic RCS of the models and layouts of blocks of 2-bit anisotropic MCs are in good agreement. The calculated and measured levels of monostatic RCS reduction of the main blocks are at least 12.5 - 13.5 dB at different co-polarizations in the band from 10.2 to 17.5 GHz and higher (based on the results of calculations).

Integral Ext2 Between Hook Weyl Modules

This paper concerns representations of the integral general linear group. The extension groups $Ext^2$ between any pair of hook Weyl modules are determined via a detailed study of cyclic generators and relations associated to certain extensions. As a corollary, the modular extension groups $Ext^1$ between such modules are determined.

Codimension two cycles in Iwasawa theory and tensor product of Hida families

The purpose of this paper is to build on results in higher codimension Iwasawa theory. The setting of our results involves Galois representations arising as cyclotomic twist deformations associated to (1) the tensor product of two cuspidal Hida families F and G, and (2) the tensor product of three cuspidal Hida families F, G and H. On the analytic side, we consider (1) a pair of 3-variable Rankin–Selberg p-adic L-functions constructed by Hida and (2) a balanced 4-variable p-adic L-function (due to Hsieh and Yamana) and an unbalanced 4-variable p-adic L-function (whose existence is currently conjectural). In each of these setups, when the two p-adic L-functions generate a height two ideal in the corresponding deformation ring, we use codimension two cycles of that ring to relate them to a pair of pseudo-null modules.

Discovery and mechanism of a pH-dependent dual-binding-site switch in the interaction of a pair of protein modules

Many important proteins undergo pH-dependent conformational changes resulting in "on-off" switches for protein function, which are essential for regulation of life processes and have wide application potential. Here, we report a pair of cellulosomal assembly modules, comprising a cohesin and a dockerin from Clostridium acetobutylicum, which interact together following a unique pH-dependent switch between two functional sites rather than on-off states. The two cohesin-binding sites on the dockerin are switched from one to the other at pH 4.8 and 7.5 with a 180° rotation of the bound dockerin. Combined analysis by nuclear magnetic resonance spectroscopy, crystal structure determination, mutagenesis, and isothermal titration calorimetry elucidates the chemical and structural mechanism of the pH-dependent switching of the binding sites. The pH-dependent dual-binding-site switch not only represents an elegant example of biological regulation but also provides a new approach for developing pH-dependent protein devices and biomaterials beyond an on-off switch for biotechnological applications.

Polarization-independent single-photon switch based on a fiber-optical Sagnac interferometer for quantum communication networks.

An essential component of future quantum networks is an optical switch capable of dynamically routing single photons. Here we implement such a switch, based on a fiber-optical Sagnac interferometer design. The routing is implemented with a pair of fast electro-optical telecom phase modulators placed inside the Sagnac loop, such that each modulator acts on an orthogonal polarization component of the single photons, in order to yield polarization-independent capability that is crucial for several applications. We obtain an average extinction ratio of more than 19 dB between both outputs of the switch. Our experiment is built exclusively with commercial off-the-shelf components, thus allowing direct compatibility with current optical communication systems.

Network modules linking expression and methylation in prefrontal cortex of schizophrenia

ABSTRACT Tremendous work has demonstrated the critical roles of genetics, epigenetics as well as their interplay in brain transcriptional regulations in the pathology of schizophrenia (SZ). There is great success currently in the dissection of the genetic components underlying risk-conferring transcriptomic networks. However, the study of regulating effect of epigenetics in the etiopathogenesis of SZ still faces many challenges. In this work, we investigated DNA methylation and gene expression from the dorsolateral prefrontal cortex (DLPFC) region of schizophrenia patients and healthy controls using weighted correlation network approach. We identified and replicated two expression and two methylation modules significantly associated with SZ. Among them, one pair of expression and methylation modules were significantly overlapped in the module genes which were significantly enriched in astrocyte-associated functional pathways, and specifically expressed in astrocytes. Another two linked expression-methylation module pairs were involved ageing process with module genes mostly related to oligodendrocyte development and myelination, and specifically expressed in oligodendrocytes. Further examination of underlying quantitative trait loci (QTLs) showed significant enrichment in genetic risk of most psychiatric disorders for expression QTLs but not for methylation QTLs. These results support the coherence between methylation and gene expression at the network level, and suggest a combinatorial effect of genetics and epigenetics in regulating gene expression networks specific to glia cells in relation to SZ and ageing process.

Experimental study on the effect of dust deposition on photovoltaic performance at various tilts in semi-arid environment

This article presents an experimental study of dust effect on the photovoltaic system's performance for various tilt angles in semi-arid environment. For analysis, eight PV modules were installed on the roof of a building at tilt angles of 0°, 15°, 30°, and 45° with an azimuth angle of 0°. Each pair of PV modules were installed at the same tilt angle. In each pair of modules, one was cleaned every two weeks and the other one was left under outdoor environmental condition. In order to analyze PV performances, the output power of the modules, as well as the climate parameters, were measured every one minute. The results showed that the reduction rate of PV performance due to dust accumulation is strongly dependent on the tilt angle. A dust storm has occurred in the mid-test period, which has reduced the daily average energy generated of PV modules at tilt angles of 0°, 15°, 30°, and 45° by 58.2%, 27.8%, 21.7%, and 20.7%, respectively. However, for a few weeks before the dust storm, the average reduction ratio of the daily energy generated of PV modules due to dust accumulation was 8.6% for the horizontal module and 0.8% for the other tilted modules.

The reduction of 176Lu background in Lu-based PET scanners using optimized classification

Positron emission tomography (PET) using scanners incorporating lutetium-based (Lu-based) scintillators are widely used in nuclear medicine. However their application in imaging very low (<100 kBq) activity distributions is quite limited due to the intrinsic 176Lu radiation emitted from the scintillators. To visualize very low activities, 176Lu background needs to be reduced or removed. This study proposes a classification method to select background coincidences from true coincidences arising from the source by supervised learning using the optimal classifier as determined by investigating 5 different classifiers: logistic regression, support vector machine, random forest, extreme gradient boosting (XGBoost) and deep neural network. Five energy and time-of-flight (TOF) related features from each coincidence event are extracted to form the training and test set in the classification. The proposed method was verified on a pair of TOF-PET detector modules. Since the measured source coincidences cannot be differentiated from the background events experimentally, simulated source coincidences are used to train the classification model. The simulated feature spectra are therefore compared with those obtained from measurement to verify the feasibility of classifying measured coincidences using a model learned by simulation. XGBoost classifier performed most effectively in classifying the coincidences and provided impressively high classification accuracy (>99%). It was subsequently tested by imaging point-like source, planar Derenzo and bar phantoms with the pair of TOF-PET detectors. An 89.4% image contrast enhancement for the Derenzo phantom at an activity concentration of 100 Bq mm−2, and a 52.4% peak-to-valley ratio improvement across the area of bar phantom at a concentration of 25 Bq mm−2, were observed on the reconstructed images with XGBoost classification applied. The proposed method could extend the usage of Lu-based PET scanners to very low activity detection and imaging and has the potential to be used in a variety of molecular imaging tasks to detect low-level signals.

A Photonic Approach for Doppler Frequency Shift Measurement With Dispersion Medium

We propose and experimentally demonstrate a novel and simple approach to identifying both the direction and value of Doppler frequency shift (DFS) in this paper. A pair of phase modulators, as well as a dispersion medium in between them, are employed in the approach. The different dispersion-induced phase shifts of the upper and lower sidebands after passing the dispersion medium can be used to determine the direction of DFS. The value of DFS is characterized by measuring the frequency of the output signal from a low-speed photodetector. Experimental results verify the feasibility of the approach. The major advantages of the approach lie in that it can measure both the DFS direction and value while avoids the use of complicated modulators and additional reference signal, which greatly simplifies the system's architecture.

Development of Multiscale Transcriptional Regulatory Network in Esophageal Cancer Based on Integrated Analysis.

Objective To explore multiscale integrated analysis methods in identifying key regulators of esophageal cancer (ESCA). Methods We downloaded the ESCA dataset from The Cancer Genome Atlas (TCGA) database, which contained RNA-seq data, miRNA-seq data, methylation data, and clinical phenotype information. Then, we combined ESCA-related genes from the NCBI-GENE and OMIM databases and RNA-seq dataset from TCGA to analyze differentially expressed genes (DEGs). Meanwhile, differentially expressed miRNAs (DEmiRNAs) and genes with differential methylation levels were identified. The pivot–module pairs were established using the RAID v2.0 database and TRRUST v2 database. Next, the multifactor-regulated functional network was constructed based on the above information. Additionally, gene corresponding targeted drug information was obtained from the DrugBank database. Moreover, we further screened regulators by assessing their diagnostic value and prognostic value, especially the value of distinguishing patients at TNM I stage from normal patients. In addition, the external database from the Gene Expression Omnibus (GEO) database was used for validation. Lastly, gene set enrichment analysis (GSEA) was performed to explore the potential biological functions of key regulators. Results Our study indicated that CXCL8, CYP2C8, and E2F1 had excellent diagnostic and prognostic values, which may be potential regulators of ESCA. At the same time, the good early diagnosis ability of the three regulators also provided new insights for the diagnosis and early treatment of ESCA patients. Conclusion We develop a multiscale integrated analysis and suggest that CXCL8, CYP2C8, and E2F1 are promising regulators with good diagnostic and prognostic values in ESCA.

Wearable Coaching System

Wearable Coaching System is a multi-sensor device for real-time training coaching. The system comprises of six modules which are shoulder, waist, a pair of wrist and a pair of ankle modules. It is compact, light, comfortable to wear and is suitable for any size of user. It system has five main embedded sensors: heart rate, three-axis acceleration, gyro, temperature and blood oxygen saturation (SpO2) sensor. It operates in streaming mode for real-time data processing using two telecommunication tools: ZigBee and Bluetooth and low energy interface for recording mode is using an internal flash memory. In this paper, a wearable coaching system is designed to help athlete or trainer to perform proper and efficient exercise suitable to one's body needs. It measures the parameter of the body, analyze and provide feedback in a form of an advice. In order to improve the system, arm gesture mode performed by the wrist modules of the system is applied. This mode is to enable user to manage their exercising level to a more appropriate pace, suitable with their individual body by reproducing the feedback. In a supervised coaching training, percentage of heart rate threshold target is increasing, hence, producing a greater performance of training. It is proven in this paper, that wearable coaching system performs an accurate measurement in enhancing sports and coaching training, adding value to novel lifestyle exercising and health monitoring.

All-fiber self-mixing laser Doppler velocimetry with much less than 0.1 pW optical feedback based on adjustable gain.

The all-fiber self-mixing laser Doppler velocimetry with adjustable gain is experimentally investigated based on a distributed Bragg reflector fiber laser. In the measurement system, the modulation gain of the injected light in the laser cavity is adjusted by a pair of fiber-coupled acousto-optic modulators (AOMs) in the external cavity, which can change the intensity and frequency of the self-mixing modulation effect. Simultaneously, the minimum feedback intensity from the target to the laser for successful measurements is 0.063 pW. Thus, the all-fiber laser velocimetry can adapt to the detection of ultraweak optical feedback and wide-range velocity measurements in various complex scenes.

Characterization of four readout circuits for an MR compatible, preclinical PET detector

We are building a high sensitivity preclinical PET/MRI insert using a highly multiplexed light sharing PET module. Each module incorporates four 19 × 19 arrays of 1 × 1 × 20 mm3 LYSO crystals with dual-ended DOI encoding readout, requiring 32 readout channels for positioning and eight channels for timing. These constraints necessitate compact, robust electronics for digitization. We have characterized four linearized time-over-threshold circuits based on these detector requirements. The four circuits allow for high channel density and can digitize signals from highly multiplexed light sharing detectors. Each circuit digitizes one channel of a multiplexed SiPM array, yielding a binary output that interfaces directly with an FPGA. Using the optimal circuit, we have characterized the performance of a pair of PET modules. The four circuits were characterized based on linearity of the 22Na photopeak positions and energy resolution at 511 keV, as well as separation of elements in a 10 × 10 array of 1.2 mm LYSO crystals coupled with a specular reflector. Practical measures of performance were comparable to those obtained with a DRS evaluation board, which served as a reference acquisition system. The ratio of the 22Na photopeak positions was 2.0 for each circuit and the reference system, implying 20% saturation due to the SiPM. PET energy resolution of the optimal circuit was 11.8% FWHM for a single crystal versus 12.6% for the reference system, and crystals were equally well separated in all cases. PCBs implementing the optimal readout circuit were fabricated and used to construct two complete detector modules. Crystals in each of the four blocks in the module were well resolved, with a mean energy resolution of 24.4 ± 4.7%. Two modules operating in coincidence showed a single detector timing resolution of 3.0 ns, which is appropriate for preclinical applications.

Support and rank varieties of totally acyclic complexes

Support and rank varieties of modules over a group algebra of an elementary abelian p -group have been well studied. In particular, Avrunin and Scott showed that in this setting, the rank and support varieties are equivalent. Avramov and Buchweitz proved an analogous result for pairs of modules over arbitrary commutative local complete intersection rings. In this paper we study support and rank varieties in the triangulated category of totally acyclic chain complexes over a complete intersection ring and show that these varieties are also equivalent.

Recovery of o-toluidine and p-toluidine from wastewater by silicon rubber membrane extraction

Abstract Wastewater treatment has become a major global issue due of undegradable pollutants. As toxic water pollutants, namely o-toluidine and p-toluidine are difficult to treat, this study uses the silicon rubber technology to treat them. A pair of modules having single tabular nonporous silicon rubber tube and HCl stripping solution were set up to extract o-toluidine and p-toluidine from high-saline wastewater. Reaction quotient ( Q C ) was calculated after every 12 h intervals to evaluate the equilibrium reaction. The effect of concentration, pH, temperature, ionic strength, and flow rate on the permeability (P) and removal efficiency ( η ) were investigated to illustrate the process parameters and mechanisms of recovery of both elements from wastewater. The results showed that the recovery efficiency was more than 96% with concentration of 2–10g/L. When pH of the extraction solution was 2 or less, the pollutant permeability efficiency was nearly 95%. Moreover, when the salting strength was over 10%, the recovery efficiency increased quickly to some extent. Permeability, which mainly influenced by membrane resistance and desorption rate, initially increased and then decreased when the water flow increased from 2 and 20 mL/min. Aging of silicon rubber tube was also studied with respect to salinity, temperature, and acidity. Acidity and temperature was found to have a significant effect on the tube, permeability increased with an increase in aging, and aging had a minor effect on the elastic properties of the silicon rubber tube. Absorption and diffusion of water in silicon rubber tubes decreased when salinity increased more than 10%, which increased separation of p-toluidine and water. Due to this, there is no need of desalination before membrane extraction in treatment of p-toluidine wastewater with high saline. Thus, this study demonstrates that membrane extraction is a highly energy-efficient process for the effective recovery of o-toluidine and p-toluidine from wastewater with high salinity.

Monoidal categorification and quantum affine algebras

We introduce and investigate new invariants of pairs of modules$M$and$N$over quantum affine algebras$U_{q}^{\prime }(\mathfrak{g})$by analyzing their associated$R$-matrices. Using these new invariants, we provide a criterion for a monoidal category of finite-dimensional integrable$U_{q}^{\prime }(\mathfrak{g})$-modules to become a monoidal categorification of a cluster algebra.

STUDYING 'LIVE' CROSS-PLATFORM CIRCULATION OF IMAGES WITH A COMPUTER VISION API: AN EXPERIMENT BASED ON A SPORTS MEDIA EVENTd'Andréa, Carlos Frederico de Brito (Federal University of Minas Gerais, Brazil) &lt;carlosfbd@gmail.com&gt;

Considering the importance of cross-platform circulation of web contents for digital methods-oriented research, in this study we aim to expand the types of digital objects used as ‘traffic tags’ by focusing on static images as traces of online associations. We pursue this goal through a methodological experiment with Google Cloud Vision API, a computing framework for visual content analysis. Its Web Detection module pairs typical computer vision operations with Google’s search mechanism, partly performing as a more specialized batch reverse image search engine. This feature thus allows to potentially retrieve images’ spread across the web. We discuss the implications of this non-verbal methodological approach by tracking the 'live' cross-platform circulation of images shared on Twitter in the context of 2018 FIFA World Cup Final Draw ceremony, held on December 2017. Following a novel methodological protocol, we ran several iterations of Vision API processing, thus generating a time series of URLs pointing to pages in which images matching the ones being processed were found. The study analyses in depth the circulation of four popular images about the broadcasted media event, observing their ‘live’ spreading dynamics as well as the computer vision API performance. Among the findings, we point out the adoption of images as 'traffic tags' for cross-platform analysis as a promising approach to study web circulation beyond language barriers and mainstream platforms. Also, we find relevant data to discuss the specificities of the API’s algorithms and its opacity as inherent issues of the digital methods approach.