Concept Of Modulation Research Articles

Different characterization of soft substructures in quantale modules dependent on soft relations and their approximations

<abstract> <p>The quantale module introduced by Abramsky and Vickers, engaged a large number of researchers. This research article focuses the combined behavior of rough set, soft set and an algebraic structure quantale module with the left action. In fact, the paper reflects the generalization of rough soft sets. This combined effect is totally dependent on soft binary relation including aftersets and foresets. Different soft substructures in quantale modules are defined. The characterizations of soft substructures in quantale modules based on soft binary relation are presented. Further, in quantale modules, we define soft compatible and soft complete relations in terms of aftersets and foresets. Furthermore, we use soft compatible and soft complete relations to approximate soft substructures of quantale modules and these approximations are interpreted by aftersets and foresets. This concept generalizes the concept of rough soft quantale modules. Additionally, we describe the algebraic relationships between the upper (lower) approximations of soft substructures of quantale modules and the upper (lower) approximations of their homomorphic images using the concept of soft quantale module homomorphism.</p> </abstract>

Third-Harmonic-Type Modulation Minimizing the DC-Link Energy Storage Requirement of Isolated Phase-Modular Three-Phase PFC Rectifier Systems

A three-phase ac/dc converter with high-frequency isolation can be realized as a monolithic three-phase or as a phase-modular system by combining three single-phase Power Factor Correction (PFC) rectifier modules with individual isolated dc-dc converters. Advantageously, for a phase-modular system the module configuration can be changed depending on the instantaneous input-output voltage ratio (i.e., a star-(Y)- or a delta-(Δ)-arrangement such that wide voltage ranges can be covered without a massive over-dimensioning of the main power components. However, the main disadvantage of a phase-modular converter realization is the fact that the input power of each PFC rectifier module pulsates at twice the mains frequency (which is inherent to single-phase power conversion) such that large dc-link capacitors are required. Recent literature predicts a substantial power pulsation reduction enabled by means of third-(3 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rd</sup> )-harmonic injection modulation which is applicable for the Y-connection (where a common-mode (CM) / zero-sequence (ZS) voltage is injected), and for the Δ-connection of the three single-phase PFC rectifier modules (where a CM / ZS current is injected). This changes the distribution of the power flow in the three-phase system and the power pulsation is shifted to higher frequencies. This paper experimentally verifies and extends the dc-link energy storage requirement reduction of the 3 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rd</sup> -harmonic injection modulation concept: In a first step, the derivation of the harmonic injection concept is recapitulated and suitable control methods are discussed for both CM voltage (Y-arrangement) and CM current (Δ-arrangement) injection. Further, an alternative CM voltage injection strategy with simplified reference generation based only on the instantaneous grid voltage measurements is presented and compared to the pure 3 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rd</sup> -harmonic injection modulation. Measurement results obtained from a 6 kW prototype reveal a dc-link voltage variation and/or energy buffering reduction by up to 38.6 % enabled by the harmonic injection modulation compared to conventional operation without 3 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rd</sup> -harmonic injection modulation.

A Consequent Pole Single Rotor Single Stator Vernier Design to Effectively Improve Torque Density of an Industrial PM Drive

The Vernier machine can utilize magnetic-gear effect, which conspicuously improves the torque production over other type of synchronous machines. However, a dual-rotor/dual-stator structure enabled high torque density Vernier design is often unfavorable for industrial applications, due to manufacturing complexity and thermal management challenges. This article successfully addresses this problem, by building magnetic-gear effect into a consequent pole enabled alternating flux barrier structure with single-rotor single-stator (SRSS). In this way, the proposed machine can achieve a superior torque density as a Vernier machine does, while maintaining an equivalent manufacturing complexity as a conventional SRSS synchronous machine. This article begins with elaborating generic analytical equations, which can transform into a Vernier machine or an SRSS synchronous machine. More specifically, the magnetic-gear effect is manifested in the equations, via stator teeth originating flux modulation concept and resulting multiharmonic field coupling effects. An SRSS Vernier topology with consequent pole and V-shape magnet is then proposed. A considerable 52.6% improvement on the torque production with comparable efficiency is validated by experiments, where the comparison is made over that of a benchmark rare earth PM machine. Power factor would fall behind with increasing current load. Overall, this new design achieves an outstanding torque density, showing solid potential and feasibility for industry adoption.

A Note On E-Injective Modules

Let 𝑅 be a commutative ring with identity, 𝑀 an 𝑅-module and 𝐸 a torsion-free 𝑅-module. A &#x0D; submodule 𝑁 of 𝑀 is said to be essential (large) in 𝑀 if the intersection of 𝑁 with each nonzero &#x0D; submodule of 𝑀 is nonzero, that is, 𝑁 ∩ 𝑅𝑚 ≠ 0 for any nonzero element 𝑚 ∈ 𝑀 and we write &#x0D; 𝑁 ≤𝑒 𝑀. It is clear that the class of 𝑒 − 𝑒𝑥𝑎𝑐𝑡 sequences is larger than the class of 𝑒𝑥𝑎𝑐𝑡&#x0D; sequences. In this study we present the concept of e-injective modules as a generalization of &#x0D; injective modules. The main goal is to give a characterization of e-injective modules in terms of &#x0D; contravariant functor 𝐻𝑜𝑚(−,𝐸)

Determining patterns of vertical load on the prototype of a removable module for long-size cargoes

The object of this study is the processes of occurrence, exposure to, and redistribution of loads in the supporting structure of a removable module for the transportation of long cargoes. To adapt platform cars to the transportation of long loads, it is proposed to introduce a removable module with elastic-friction connections in the structure. In order to select the optimal profiles for the removable module, in terms of minimal material consumption, the calculation was carried out in the Lira software package. Based on the calculation results, a spatial model of the concept of the removable module was built. To determine the dynamic loads that act on the platform car loaded with a removable module, a mathematical simulation was carried out. It was established that the use of elastic-friction links in the structure of the removable module helps reduce its dynamic load, as well as the platform car, by 4.6 %. The resulting acceleration was taken into account when calculating the strength of the removable module. The calculation results showed that the strength of the removable module under operational loads is ensured. A feature of the reported results is that the proposed design of a removable module makes it possible not only to adapt the platform car to the transportation of long loads but also to reduce its load in operation. The scope of practical application of the results includes the engineering industry, in particular, railroad transport. Worth noting is that the conditions for the practical use of the results imply the introduction of elastic-friction links in the structure of the removable module. The reported research will contribute to compiling recommendations for the design of modern vehicle structures, in particular removable type, as well as for improving the efficiency of rail transportation.

Autofocusing and imaging algorithm for moving target by vortex electromagnetic wave radar

Electromagnetic (EM) vortex imaging, which combines with spiral wavefront phase modulation and computational imaging concept introduced by orbital angular momentum (OAM), has demonstrated superior performance in target information extraction and two-dimensional (2-D) or even three-dimensional (3-D) imaging capability in forward-looking observation geometry. However, due to the unknowns and complexity of target motion, the translational component will lead to the disturbance of echo phase, which hinders the motion compensation between target echo pulses and causes imaging defocus. In this paper, a high-resolution imaging algorithm based on Fourier ptychography (FP) is proposed for moving target autofocusing imaging by vortex electromagnetic forward-looking radar (VEMFLR). Firstly, based on the spatial geometric model and echo model of VEMFLR, high-order phase terms caused by target motion are derived, which provides a theoretical basis for applying FP phase retrieval to autofocusing imaging; Then, the spectrum information in FP sub-aperture is obtained; Thirdly, the imaging method, based on FP phase retrieval, is exploited to compensate phase error and obtain a well-focused image. Simulation results show that this method can achieve fine imaging performance without estimating target motion parameters.

Virtual Research Group Modules: Scalable Simulations of STEM Research

Laboratory research experiences can be an important part of the training process for STEM professionals, but barriers exist that can prevent broad access to these opportunities. Virtual Research Group (VRG) modules, which use data curated from the scientific literature to simulate aspects of the research process, provide a scalable alternative to traditional in-lab research experiences. Here we describe the general concept of VRG modules and the implementation of a VRG module focused on block copolymers in both a high school outreach program and an undergraduate materials science course. Through qualitative and quantitative data analysis of student postsurvey responses, we demonstrate that VRG modules effectively simulate many of the attributes of traditional research experiences. We also compare student experiences when VRG modules are offered in three different formats: (i) competitive in-person, (ii) competitive virtual, and (iii) collaborative virtual. Finally, we demonstrate that VRGs can be applied to topics other than block copolymers through implementation of a VRG module on bulk metallic glass.

Inverse Design of Nonvolatile Reconfigurable Mode Generator and Optical Circulator Based on a Novel Concept of a Fully-Digitized Module

Based on the novel concept of a fully-digitized module, we employ a forward-designed-assisted inverse design method to design a nonvolatile reconfigurable mode generator and an optical circulator, assisted with a phase change material. The mode generator can selectively output different modes. The fundamental transverse electric (TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ) or TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> modes can be selectively generated when the TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> mode is launched in the input port. The mode generator with an effective footprint of 2.4 μm × 16 μm exhibits the simulated insertion losses of less than 1.0 dB and the simulated crosstalks of lower than –19.0 dB for both the TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> and TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> modes from 1540 nm to 1560 nm. The optical circulator enables the light unidirectional propagation. Photons can be precisely routed from each input port to one adjacent output port in clockwise or counterclockwise directions. The simulated results indicate that the circulator with an effective footprint of 24 μm × 24 μm, can provide both the simulated insertion losses of less than 0.8 dB and the simulated crosstalks of lower than –16.3 dB from 1540 nm to 1560 nm in both clockwise and counterclockwise directions. The fabrication tolerances caused by the expansion or contraction of the etched pattern contour are also investigated. In principle, the proposed frameworks can be extended to an arbitrary number of ports for designing mode generators and optical circulators.

Comparison review between monofacial and bifacial solar modules

The objects of the study are solar modules. The world has witnessed a change in all aspects of life, especially in the last period, when the world witnessed an increase in the demand for energy and all regions. Here the imperfection appeared in meeting the energy needs, just as the traditional sources (oil, coal, and natural gas), for example, are no longer hope as they are non-renewable sources. In addition to these sources, to exploit the energy in them, we must burn, which pollutes the environment, in addition to the cost of transportation. Not long ago, solar energy began to produce electricity through photovoltaic modules, and competition began to make photovoltaic modules with higher efficiency. The main aim of this study is to clarify the concept of bifacial photovoltaic modules and show some differences between them and monofacial photovoltaic modules. The current report consists of the definition of bifacial photovoltaic modules and their most important specifications, comparing them with monofacial photovoltaic modules, which are the best, the factors affecting their energy production, and the type of radiation used in each type. In fact, the utilization of albedo radiation for monofacial photovoltaic modules does not exceed 2 %, while this percentage is exceeded in bifacial photovoltaic modules. So, it can be recommended here that the trend to use bifacial photovoltaic modules can be economical and space-saving space because it produces more amount of electricity for the same unit area, which in turn this spaces it available for other applications, and also, increase the amount of electricity due to the increase in the effective side size (two sides: one upwards and the other is downward) of the solar modules.

Microbial active functional modules derived from network analysis and metabolic interactions decipher the complex microbiome assembly in mangrove sediments

BackgroundThe metabolic interactions of microbes significantly affect the assembly of microbial communities that play important roles in biogeochemical processes. However, most interspecies interactions between microorganisms in natural communities remain unknown, leading to a poor understanding of community assembly mechanisms.ResultsHere, we used a genome-scale metabolic modeling-based approach to explore the potential interactions among bacteria and archaea in mangrove sediments. More than half of the assembled microbial species (backsim 340) combined about 3000 pairwise metabolic interaction relationship with high potential. The examples of predicted interactions are consistent with the implications of studies based on microbial enrichment/culture, indicating the feasibility of our strategy for extracting diverse potential interactions from complex interspecies networks. Moreover, a substantial number of previously unknown microbial metabolic interactions were also predicted. We proposed a concept of microbial active functional module (mAFM), defined as a consortium constituted by a group of microbes possessing relatively high metabolic interactions via which they can actively realize certain dominant functions in element transformations. Based on the metabolic interactions and the transcript distribution of microorganisms, five mAFMs distributed in different layers of the sediments were identified. The whole group of mAFMs covered most of the principal pathways in the cycle of carbon, nitrogen, and sulfur, while each module possessed divergently dominant functions. According to this distinction, we inferred that the mAFMs participated in the element cycles via their intra-cycle and the inter-exchange among them and the sediments.ConclusionsThe results of this study greatly expanded interaction potential of microbes in mangrove sediments, which could provide supports for prospective mutualistic system construction and microbial enrichment culture. Furthermore, the mAFMs can help to extract valuable microbial metabolic interactions from the whole community and to profile the functioning of the microbial community that promote biogeochemical cycling in mangrove sediments.F-NFn2HGRi3jBYiToka5XdVideo

A new ice breaker module concept

During the winters, the waters of the rivers freeze because of the low temperatures. In such situations, it is necessary to ensure the traffic of cargo and passenger ships that the formed ice patches be broken and cleared. Ice breakers are used for this purpose. These ships are of special construction that require significant investments. In this paper, a con-cept of an icebreaker module that can be attached to an existing tugboat in service is pro-posed. The paper presents a concept adapted to the Danube river and to an existing tug in service on the same river.

Reconfigurable Intelligent Surface Assisted Space-Time Line Code for SIMO Transmission

In this contribution, we investigate reconfigurable intelligent surface assisted space-time line code (RIS-STLC) transmission for enhancing the signal quality when the direct link between the transmitter and receiver is blocked. In the context of intelligent transmission by RIS, the concept of index modulation (IM) is integrated into the pursuit of higher spectral efficiency, while a two-step detection is developed to improve the performance. Correspondingly, for blind transmission where the channel information at RIS is not available, the phase at RIS not associated with the channel is considered. Subsequently, the bit-error-rate (BER) performances of the proposed RIS-STLC system conditioned on both the intelligent and blind transmission are quantified. Theoretical analysis and simulation results demonstrate the effectiveness of the development of RIS-STLC.

Lower Extremity Malformations.

Lower Extremity Malformations.

Photoacoustic methane detection inside a MEMS microphone

An innovative laser based photoacoustic (PA) gas sensing concept with intrinsic miniaturization potential was developed and investigated for methane trace gas detection. An interband cascade laser (ICL) with an optical power of 8.5 mW targets a methane (CH4) absorption line feature around 3057.7 cm−1 (or 3270 nm). The ICL was focused into the sound port of a MEMS microphone, where the PA signal was generated and detected using a wavelength modulation concept (2f-WMS-PAS). The MEMS microphone was successfully implemented as an intrinsically miniaturized PA cell being gas sensing volume, acoustic resonator and sound transducer at once. Frequencies between 2 kHz and 100 kHz were investigated and used for methane detection. A sensitive and resonant methane detection at 41.8 kHz was investigated by concentration variations between 0 and 10 ppm CH4 in N2. A limit of detection (3σ-LOD) of 329 ppb was estimated. The long term stability of this sensor was investigated by the measurement of methane in ambient air. A noise equivalent concentration (NEC) of 14 ppb (parts per billion) at an average time of 10 s was estimated. This value corresponds to a normalized noise equivalent absorption (NNEA) of 2⋅10−8 W cm−1 Hz−1/2. Using the MEMS microphone directly as PA cell offers the possibility for an extremely miniaturized, highly sensitive and very cost-efficient photoacoustic trace gas sensor.

Modeling and Analysis of Microwave Emission from Multiscale Soil Surfaces Using AIEM Model

Natural rough surfaces have inherent multiscale roughness. This article presents the modeling and analysis of microwave emission from a multiscale soil surface. Unlike the linear superposition of different correlation functions with various correlation lengths, we applied the frequency modulation concept to characterize the multiscale roughness, in which the modulation does not destroy the surface’s curvature but only modifies it. The multiscale effect on emission under different observation geometries and surface parameters was examined using an AIEM model. The paper provides new insights into the dependence of polarized emissivity on multiscale roughness: V-polarized emissivity is much less sensitive to multiscale roughness across the moisture content from dry to wet (5–30%). The H-polarized is sensitive to multiscale roughness, especially at higher moisture content. The predicted emissivity will have considerable uncertainty, even for the same baseline correlation length, without accounting for the multiscale roughness effect. V-polarized emissivity is less sensitive to the multiscale effect than H-polarized and the higher modulation ratio indicates larger emissivity. The higher modulation ratio indicates larger emissivity. Multiscale roughness weakens the polarization difference, particularly in higher moisture conditions. In addition, ignoring the multiscale effect leads to underestimated emissivity to a certain extent, particularly at the larger RMS height region. Finally, when accounting for multiscale roughness, model predictions of emission from a soil surface are in good agreement with two independently measured data sets.

Media Modulation Based Molecular Communication

In conventional molecular communication (MC) systems, the signaling molecules used for information transmission are stored, released, and then replenished by a transmitter (TX). However, the replenishment of signaling molecules at the TX is challenging in practice. Furthermore, in most envisioned MC applications, e.g., in the medical field, it is not desirable to insert the TX into the MC system, as this might impair natural biological processes. In this paper, we propose the concept of media modulation based MC where the TX is placed outside the channel and utilizes signaling molecules already present inside the system. The signaling molecules can assume different states which can be switched by external stimuli. Hence, in media modulation based MC, the TX modulates information into the state of the signaling molecules. In particular, we exploit the group of photochromic molecules, which undergo light-induced reversible state transitions, for media modulation. We study the usage of these molecules for information transmission in a three-dimensional duct system, which contains an eraser, a TX, and a receiver for erasing, writing, and reading of information via external light, respectively. We develop a statistical model for the received signal which accounts for the distribution of the signaling molecules in the system, the initial states of the signaling molecules, the reliability of the state control mechanism, the randomness of irrepressible, spontaneous state switching, and the randomness of molecule propagation. We adopt a maximum likelihood detector and show that it can be reduced to a threshold based detector. Furthermore, we derive analytical expressions for the optimal threshold value and the resulting bit error rate (BER), respectively. Both the statistical model and BER results are verified by computer simulations. Our results reveal that media modulation enables reliable information transmission, validating it as a promising alternative to MC based on molecule emitting TXs.

Modular Model-Predictive Control With Regulated Third-Harmonic Injection for Zero-Sequence Stabilized Inverter

A modular model-predictive control (MPC) method for a nonisolated three-phase <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$LCL$</tex-math></inline-formula> grid-connected converter is proposed with zero-sequence voltage control and regulated third-harmonic injection capabilities. The control method is proposed with the combination of a modified three-phase <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$LCL$</tex-math></inline-formula> converter topology to stabilize the common-mode voltage. The control mechanism consists of two layers: 1) the central-level control of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$dq$</tex-math></inline-formula> -sequence output current control cascaded with 2) the local-level control of zero-sequence voltage three-phase inductor current/capacitor voltage MPC. No grid-side inductance value is needed for the two-layer cascaded control structure, which both improves the dynamic performance from the inner MPC loop and avoids the MPC parametric error caused by the uncertainty of grid-side inductance. With the zero-sequence MPC, the common-mode voltage and leakage current can be attenuated without a bulky isolation transformer. A regulated third-harmonic injection (RTHI) method is designed based on the zero-sequence voltage control and the proposed modified converter topology to improve the dc bus utilization and avoid the overmodulation issue. Compared with the conventional third-harmonic injection methods, no extra harmonics are injected to the grid, and there is no need for a specialized grid total harmonic distortion optimization algorithm with the proposed zero-sequence-controlled RTHI. The stability and robustness of the proposed RTHI method are also improved with the zero-sequence MPC regulation. In addition, the modular concept of the local MPC module enables the extensibility for the power converter control with a flexible number of phases. The dynamic performance, leakage current attenuation, dc bus utilization, and grid-connection power quality of the proposed MPC method with RTHI have been validated experimentally.

On normal modules

Recall that a commutative ring is said to be a normal ring if it is reduced and every two distinct minimal prime ideals are comaximal. A finitely generated reduced R-module is said to be a normal module if every two distinct minimal prime submodules are comaximal. The concepts of normal modules and locally torsion free modules are different, whereas they are equal in theory of commutative rings. We give many properties and examples of normal modules, we use them to characterize locally torsion free modules and Baer modules. Also, we give the topological characterizations of normal modules.

Limited-damage 3D-printed interlocking connection for timber volumetric structures: Experimental validation and computational modelling

Cross laminated timber volumetric construction (CLTVC) is an innovative construction technology that combines the sustainability of timber and the efficiency of modular construction, as opposed to conventional construction. However, the connection installing methods of CLTVC, such as fastening, are laborious with limited accessibility for connection installations, thus hindering the application of CLTVC in mid- and high-rise structures. Therefore, a new way of connecting CLT modules by sliding and stacking is explored herein with a newly proposed damage-control interlocking connection system, aiming to provide a more efficient assembly solution to CLTVC that does not require onsite screwing. Quasi-static monotonic and cyclic test, and numerical analyses were conducted to assess the mechanical performance of the proposed connections, which possessed adequate translational stiffness and strength of the proposed connections. The connections' ability to control deformation, while damage is moved away from timber and the embedded fasteners, was also well demonstrated in the test, as both screws and timber remained mostly intact after testing. This novel connection design showcases a new concept of modules’ assembly in volumetric construction with higher efficiency and flexibility; meanwhile demonstrates the potential in reducing the permanent damage to structural materials during service life and enabling reuse.

Sampling Parallel SOA-MZIs Configuration for All-Optical Simultaneous Frequency Down-Conversion

In this paper, we expound a modulation concept to contrive simultaneous frequency down-conversion based on a three parallel Semiconductor Optical Amplifier Mach-Zehnder Interferometers (SOA-MZIs) link by using a band pass sampling method in a Virtual Photonics Inc. simulator. Each SOA-MZI is deployed to achieve a down-converted signal, which has ten replicas related to the first ten harmonic ranks of the sampling signal, at the SOA-MZI outer port. Then, the admixture of the three down-converted signals yields a sampled signal, which is called a simultaneous down-converted signal that contains thirty different replicas. The positive down-conversion gains with top values are reached with the sampling parallel SOA-MZIs link. Moreover, we evaluated the quality of the parallel SOA-MZIs transmission system over orthogonal frequency division multiplexing (OFDM) complex modulated signals using the error vector magnitude values as a performance index. The utmost bit rate attained is 2 Gbit/s for OFDM modulations.