Proper Topology Research Articles

Nonlocal conservation laws with time delay

This study considers nonlocal conservation laws in which the velocity depends nonlocally on the solution not in real time but in a time-delayed manner. Nonlocal refers to the fact that the velocity of the conservation law depends on the solution integrated over a specific area in space. In every model modelling human’s behavior a time delay as reaction/response time is crucial. We distinguish a so called nonlocal classical delay model where only the velocity of the conservation law is delayed from a more realistic nonlocal delay model where also a shift backwards in space is considered. For both models we show existence and uniqueness of the solutions and study their analytical properties. We also present a direct application in traffic flow modelling. We also show that for delay approaching zero, the solutions of the considered delayed models converge to the solutions of the non-delayed models in the proper topology. Finally, a comprehensive numerical study illustrating exemplary the impacts of delay and nonlocality are presented and compared with nonlocal models without delay, as well as the corresponding local models.

Miniaturized Triple-Band Highly Transparent Antenna

In this article, a novel on-glass antenna which is transparent, miniaturized, and multiband is presented. First, the antenna achieves more than 80% transparency. This is realized by removing as much as possible the metal pattern, without compromising the operational electric current flow. Second, the antenna is electrically small, $0.13\lambda \times 0.19\lambda $ at 0.95 GHz. This is realized by choosing a proper topology for the remaining metal pattern. Third, the antenna is triple band, covering the ranges 0.88–1.03 GHz, 1.47–2.74 GHz, and 3.32–5.97 GHz. The radiation is omnidirectional in all bands, which is suitable for GSM900/1800, 3G, 4G, 5G (2.55–2.65 GHz), WLAN (2.4/5.2/5.8 GHz), and WiMAX (2.5/5.5 GHz). The maximum gain in the three bands is equal to −0.18, 3.66, and 4.35 dBi with corresponding radiation efficiencies of 66%, 87%, and 88%. A prototype is made by first printing a metallic circuit on a thin FR-4 substrate and then gluing it on a glass substrate. The measurement results are in good agreement with simulations.

Topology optimization of thermal structure for isotropic and anisotropic materials using the element-free Galerkin method

ABSTRACTA numerical model of topology optimization for isotropic and anisotropic thermal structures was established by combining the element-free Galerkin (EFG) method and the rational approximation of material properties model. The relative density of EFG nodes was defined as the design variable, and the moving least-squares shape function was used to construct the relative density of calculation points. The EFG topology optimization model of anisotropic thermal structure was verified by benchmark examples based on the finite element method (FEM). The effects of the orthotropic factor and off-angle on EFG topology optimization results were studied. The results show that EFG optimal structures have better heat dissipation performance, and the boundary profiles are clearer than with FEM even without filtering techniques, enabling manufacture using 3D printing technology. The proper topology thermal structure can be obtained by adjusting the orthotropic factor and off-angle, thus improving the heat dissipation performance of the thermal structure.

Harmonizing Experimental Data with Modeling to Predict Membrane Protein Insertion in Yeast

Membrane proteins must adopt their proper topologies within biological membranes, but achieving the correct topology is compromised by the presence of marginally hydrophobic transmembrane helices (TMHs). In this study, we report on a new model membrane protein in yeast that harbors two TMHs fused to an unstable nucleotide-binding domain. Because the second helix (TMH2) in this reporter has an unfavorable predicted free energy of insertion, we employed established methods to generate variants that alter TMH2 insertion free energy. We first found that altering TMH2 did not significantly affect the extent of protein degradation by the cellular quality control machinery. Next, we correlated predicted insertion free energies from a knowledge-based energy scale with the measured apparent free energies of TMH2 insertion. Although the predicted and apparent insertion energies showed a similar trend, the predicted free-energy changes spanned an unanticipated narrow range. By instead using a physics-based model, we obtained a broader range of free energies that agreed considerably better with the magnitude of the experimentally derived values. Nevertheless, some variants still inserted better in yeast than predicted from energy-based scales. Therefore, molecular dynamics simulations were performed and indicated that the corresponding mutations induced conformational changes within TMH2, which altered the number of stabilizing hydrogen bonds. Together, our results offer insight into the ability of the cellular quality control machinery to recognize conformationally distinct misfolded topomers, provide a model to assess TMH insertion in vivo, and indicate that TMH insertion energy scales may be limited depending on the specific protein and the mutation present.

On a Class of Stochastic Differential Equations with Random and Hölder Continuous Coefficients Arising in Biological Modeling

Inspired by the paper Greenhalgh et al. (Appl Math Comput 276:218–238, 2016), we investigate a class of two-dimensional stochastic differential equations related to susceptible–infected–susceptible epidemic models with demographic stochasticity. While preserving the key features of the model considered in Greenhalgh et al. (2016), where an ad hoc approach has been utilized to prove existence, uniqueness and non-explosivity of the solution, we consider an encompassing family of models described by a stochastic differential equation with random and Hölder continuous coefficients. We prove the existence of a unique strong solution by means of a Cauchy–Euler–Peano approximation scheme which is shown to converge in the proper topologies to the unique solution.

Emphasis on switch selection and its switching loss comparison for on‐board electric vehicle charger

A DC/DC converter plays a vital role in on-board electric vehicle (EV) charger. Among the many converter topologies, the phase-shifted full-bridge DC/DC converter (PSFBDC) is widely used. For improved efficiency, PSFBDC is embedded with passive auxiliary networks resulting in several unique configurations for achieving soft-switching in entire load range. The architecture of the chosen DC/DC converter configuration should comply with the society of automotive engineers (SAE) standards. Although, the conduction loss of the converter can be minimised by choosing a proper topology configuration and proper switching of the configuration, the selection of appropriate for PSFBDC plays an important role in enhancing the overall efficiency. An optimistic method for the selection of switch configuration satisfying the reduced power loss and cost-effective aspects is presented. For demonstrating the proposed method, a 1 kW 100 kHz system with commercially available switches IRFP460, IXFN64N60P, and IPP65R045C7 is chosen and the obtained results are presented.

Identification of residues critical for topology inversion of the transmembrane protein TM4SF20 through regulated alternative translocation

Adopting a proper topology is crucial for transmembrane proteins to perform their functions. We previously reported that ceramide regulates a transmembrane protein called TM4SF20 (transmembrane 4 L six family member 20) through topological inversion by altering the direction through which the protein is translocated across membranes during translation. This regulatory mechanism, denoted regulated alternative translocation (RAT), depends on a GXXXN motif present in the first transmembrane helix of TM4SF20. Here, using site-directed mutagenesis, we show that Asn-26 in the motif is crucial for RAT of TM4SF20, as it cannot be replaced even by Gln. In contrast, Gly-22 in the motif could be substituted by other small residues such as Ala and Ser without affecting RAT of TM4SF20. We further demonstrate that the GXXXN motif alone is insufficient to induce RAT of a transmembrane protein because TM4SF4, a relative of TM4SF20 that also contains the motif in the first transmembrane helix, did not undergo RAT. Using TM4SF40-TM4SF20 chimeras, we identified Pro-29 of TM4SF20 as another important element required for RAT of the protein. Substituting Pro-29 alone did not affect RAT of TM4SF20, whereas replacing Pro-29 together with either Leu-25 or Val-17 of TM4SF20 with the corresponding residues of TM4SF4 abolished RAT of TM4SF20. Because Val-17, Gly-22, Leu-25, Asn-26, and Pro-29 are predicted to reside along the same surface of the transmembrane helix, our results suggest that interactions with other proteins mediated by this surface during translocation may be critical for RAT of TM4SF20.

Robust cascade control of a deployable cable-driven robot

Abstract In this paper, we derive the dynamic formulation of a deployable cable-driven robot that considers models of the actuator and power transmission systems, and we investigate the challenges of structural uncertainty. To accommodate the inherent uncertainty of the system, we propose a proper control topology based on a cascade structure. The inner loop of the structure controls the cable forces, and the outer loop tracks the precise position of the robot’s end-effector. For the design of the outer loop controller, we propose a robust sliding mode controller with a stability analysis that is based on the Lyapunov direct method. The main contribution of this paper is to analyze the stability of the system as a whole considering both the inner and outer loop controllers. Finally, in order to illustrate the performance of the proposed controller, we present the results of an experiment on a deployable suspended cable-driven robot, which shows the effectiveness of the proposed controller in the presence of the inherent uncertainties of the system.

철학은 하나의 학문인가?

What is the philosophy? The philosophy ask consistently this question after its birth, but an adequate answer to this question is not given yet. Heidegger asserted, in Einleitung in die Philosophie, that the philosophy is not a science of sciences. This assertion makes us very confused, who research and lecture the philosophy in the university. Although we consider the philosophy as a different thing from any other sciences, we don’t understand, that the philosophy is not a science of sciences. We make a hasty deduction according to the so-called tradition of philosophy, that the philosophy is the queen of sciences. But another sciences respect the philosophy as the queen by no means! The philosophy claim itself to be a queen of sciences. Another sciences would like to assert, “the philosophy is never a science of sciences!”BR According to Heidegger, the philosophy is not a science of sciences, because it is not a member of sciences. The philosophy is the queen of sciences, not for its brilliantness, but for being the origin of another sciences. This Heidegger’s assertion is from his own standpoint of philosophy, that Being(Sein) is different from beings(Seiendes), and then the philosophy is an ontology, which inquire into Being. Another sciences make researches in beings. For research of beings, Being is firstly inquired into, because beings become for the first time itself owing to Being. The philosophy inquire into Being, and Heidegger’s philosophy is the ontology. But his own standpoint and assertion is a controversial problem in the section of philosophy.BR Nevertheless Heidegger’s standpoint and assertion of philosophy is relevant for us, since we research and lecture now the philosophy in the university. His own standpoint and assertion of philosophy would give us a clue for answering to question, what is the philosophy. And it would be a guide for us, which suggest us, what and how we may do in our research and lecture of philosophy in the university. Although the philosophy may be not a science of sciences, it makes a great contribution to the public with another sciences in the university, if the philosophy will find his proper topology among the sciences in the university. For there are some misunderstanding and disappointment of the philosophy in the university, in the public, even in the philosophy itself.BR The contribution of the university to the public meet requests from the public through the activities of research and lecture. According to this circumstances, the philosophy must meet to requests from the public, while it may be a member of community in the university, even though it must be a science of sciences. Formation of theories in philosophy and cultivation of professional members in the philosophy is the contribution of the philosophy to the public. For this contribution, the philosophy in the university must discipline itself the introduction to the philosophy and the activity of the philosophy. The introduction to the philosophy is not only an introduction to the philosophical theories but also to the philosophical activities.BR In this paper, we will look at with attention popularly figured point of view to the university in the public, the science in the university, the philosophy in the university. And, while understanding and interpreting Heidegger’s standpoint and assertion of philosophy, we will investigate, which position the philosophy has in the university and how the philosophy meets to requests from the public.

A New Design Approach for Balanced Bandpass Filters on Right-Angled Isosceles Triangular Patch Resonator

A new approach to design a balanced bandpass filter (BPF) is presented in this letter. By virtue of resonant properties of a right-angled isosceles triangular patch resonator (RAITPR), a modified RAITPR with one electric wall and two magnetic walls is constructed. This resonator, namely, half-mode RAITPR, can support half-TM10-mode of the RAITPR. By adopting proper coupling topology between three adjacent RAITPRs and two half-mode RAITPRs, a third-order balanced BPF is proposed to achieve good differential-mode filtering selectivity and high common-mode suppression. To verify this design concept, a balanced BPF operating at 2.0 GHz with a 3-dB fractional bandwidth of 12.9% is in final designed and fabricated. Good agreement is achieved between the simulated and measured results over a wide bandwidth from 0 to 4.0 GHz.

Efficient Topology Reconstruction via Machine Learning Based Traffic Patterns Recognition in Optically Interconnected Computing System

The traffic flows in parallel computing systems show clustered, correlative nature and the flows are always latency-sensitive. These flows have been abstracted as “Coflow” to pursue overall optimization. Concurrent Coflows on the network show very novel traffic patterns. On the other hand, multiple optical interconnection network architectures have been proposed to enable the traffic adaption topology reconstructions. Nevertheless, topology reconstruction strategies are application-agnostic, and their optimization objective of network performance cannot meet the Coflow demand. In order to exert the flexibility of optical topology to promote the performance of parallel computing application by Coflow acceleration, the traffic patterns are preferred to be well recognized and then an adaptive topology is generated accordingly. To avoid further complex, such recognition is expected to finish without prior knowledge from the application layer. Then, the topology should be reconstructed to minimize the Coflow completion time. To implement these procedures, we proposed a traffic pattern-aware topology reconstruction strategy. Our strategy first combines CNN and spectral clustering to realize the traffic patterns awareness. And then, the genetic searching algorithm is used to mind the proper topology. Based on real traffic trace from Facebook computing application, large-scale simulations have verified the efficiency of such a strategy by lowering the completion time of computing jobs. In addition, the experimental demonstration has confirmed the conclusions.

Mechanisms controlling the multistage post-translational processing of endogenous Nrf1α/TCF11 proteins to yield distinct isoforms within the coupled positive and negative feedback circuits

To gain a better understanding of the multistep processing of Nrf1 to yield various isoforms with confused molecular masses, we herein establish a generally acceptable criterion required for identification of its endogenous full-length proteins and derivative isoforms expressed differentially in distinct experimental cell lines. Further work has been focused on the molecular mechanisms that dictate the successive post-translational modifications (i.e. glycosylation by OST, deglycosylation by NGLY, and ubiquitination by Hrd1) of this CNC-bZIP protein and its proteolytic processing to give rise to multiple proteoforms. Several lines of experimental evidence have demonstrated that the nascent Nrf1α/TCF11 polypeptide (non-glycosylated) is transiently translocated into the endoplasmic reticulum (ER), in which it becomes an inactive glycoprotein-A, and is folded in a proper topology within and around membranes. Thereafter, dynamic repositioning of the ER-resident domains in Nrf1 glycoprotein is driven by p97-fueled retrotranslocation into extra-ER compartments. Therein, Nrf1 glycoprotein is allowed for deglycosylation digestion by glycosidases into a deglycoprotein-B and its progressive proteolytic processing by cytosolic DDI-1/2 and proteasomes so as to generate N-terminally-truncated protein-C/D. This processing is accompanied by removal of a major N-terminal ~12.5-kDa polypeptide from Nrf1α. Interestingly, our present study has further unraveled that there exist coupled positive and negative feedback circuits between Nrf1 and cognate target genes, including those encoding its regulators p97, Hrd1, DDI-1 and proteasomes. These key players are differentially or even oppositely involved in diverse cellular signaling responses to distinct extents of ER-derived proteotoxic and oxidative stresses induced by different concentrations of proteasomal inhibitors.

Specialized chaperones required

Protein Folding Although some proteins can reach a properly folded state without assistance, many require help to adopt the correct topology and avoid kinetic trapping in nonnative states. Chaperones encapsulate guest proteins and use adenosine triphosphate (ATP)–driven conformational changes to help them fold, but not all chaperones work for all substrates. Balchin et al. compared the folding pathway of the cytoskeleton protein actin with its proper chaperone, TRiC, to the incorrect folding that occurs with the bacterial chaperone GroEL. TRiC functions by stabilizing an extended form of actin with the proper secondary structure and topology. ATP binding and hydrolysis drives release of this partially folded intermediate into the chaperone where it can successfully fold. GroEL fails to bind the intermediate properly and thus is not able to successfully fold actin, even after ATP binding and hydrolysis. Cell 174 , 1507 (2018).

Comparative Analysis of Grid Connected Transformerless Photovoltaic Inverters for Leakage Current Minimization

Objectives: To make a comparative analysis of four transformerless topologies namely H5, H6, oH5 and H-Bridge Zero Voltage State Rectifier (HBZVR) in terms of leakage current and THD. Methods/Statistical Analysis: H5, H6, oH5 and HBZVR topologies have been simulated. Then these topologies are compared in terms of leakage current and THD. Based on the comparative analysis, the topology with less leakage current and THD has been chosen for photovoltaic interface. The interfacing circuit is simulated and realized as prototype to validate the results practically. Findings: It is found from the review that HBZVR topology has less leakage current and THD. This topology employs both galvanic isolation and Common Mode Voltage (CMV) clamping. It is found that the common mode voltage in HBZVR is almost eliminated. The conclusion derived from this paper may be helpful in selecting proper topology for PV interface. Application/ Improvements: Generally, in grid connected PV inverters, transformers provide galvanic isolation between the two electrical circuits, thus preventing the flow of leakage current between the stray capacitance of PV and ground. But, ransformers reduce the overall efficiency of the system, which lead to the development of transformerless PV system. Galvanic connection exists between the PV and grid in transformerless inverter, which leads to the presence of leakage current. So, to reduce leakage current, many topologies are introduced which employs either dc-decoupling or ac-decoupling to provide galvanic isolation. The HBZVR topology provides proper isolation for PV interface where the capacitance of the panel with respect to ground is large. Keywords: Comparison, Leakage Current, Isolation, Transformerless PV Inverters, THD

Screening, large-scale production and structure-based classification of cystine-dense peptides.

Peptides folded through interwoven disulfides display extreme biochemical properties and unique medicinal potential. Their exploitation was hampered by the limited amounts isolatable from natural sources and the expense of chemical synthesis. We developed reliable biological methods for high-throughput expression screening and large-scale production of these peptides. 46 were successfully produced in multimilligram quantities, and over 600 more were deemed expressible by stringent screening criteria. Many showed extreme resistance to temperature, proteolysis, and/or reduction, and all displayed inhibitory activity against at least one of 20 ion channels tested, confirming biological functionality. Crystal structures of 12 were determined, confirming proper cystine topology, and the utility of crystallography for studying these molecules, but highlighted the need for rational classification. Previous attempts at categorization have focused on limited subsets siloed around distinct motifs. Stepping back, we present a global definition, classification, and analysis of over 700 structures of cystine-dense peptides, unifying these molecules.

The Effects of Using Some Different Types of Learning Automata on Presentation of Adaptive Neighbor-Based and Energy Efficient Topology Control Protocols in Wireless Sensor Networks

The high number of nodes and dynamic and periodic topological changes, as well as constraints in the physical size of nodes, energy resources, and power of processing are some characteristics of sensor networks that make them different from other networks. One method to overcome these constraints is topology control with the aim of reducing energy consumption and increasing the network’s capacity, which has the most influence on the network’s efficiency, especially in terms of energy consumption and lifetime. In consideration of learning Automata’s abilities, such as low computational load and adaptability to changes via low environmental feedbacks, in this paper, neighbor-based topology control protocols based on learning Automata have been proposed somehow that all nodes are equipped with Automata. The nodes try to adapt their selected actions with required conditions for creating a connected and energy efficient network by selecting the best radio range for themselves. This approach finally forms a proper topology, and in this way it lowers the network’s energy consumption in its lifetime. The exclusive characteristic of these methods is the high number of transmission ranges that each node can select as transmission radius. In the first proposed protocol, a P-model environment is used for learning phase, but in the second proposed protocol, a Q-model environment is applied. Simulation results show favorite functionality of proposed protocols in comparison with some other similar protocols from topology control point of view, as well as high improvement of achieved results for the Q-model environment.

Topology-Based Controllability Problem in Network Systems

In network systems with a huge number of nodes, it is not possible to apply input signals to all network nodes to control them. In this paper, we show that this issue can be addressed by designing a network topology so that the nodes in the network system are controllable by a few nodes in the system. A theoretical framework that provides the basic link between structural controllability of network systems and the topology design problem is developed. The results also shed light on how new nodes can be added to the network system without having to introduce new control nodes. Hence, the results are useful in dealing with topology design to obtain a controllable network. Moreover, the results also show under what circumstances a network system with multiple identical nodes is uncontrollable. In many applications, groups of identical nodes are connected to each other which is called network of groups. Here, we address the structural controllability problem for multiple groups of network systems which provides information on proper topology design at both network level (i.e., interconnection of groups) and node level (i.e., interconnection of nodes within a group).

Quasi-static analysis of mechanical properties of Ti6Al4V lattice structures manufactured using selective laser melting

Selective laser melting (SLM) is a transformative manufacturing process due to its ability to manufacture complex metal parts directly from various bulk powders. With the capability of reducing powder consumption and decreasing fabrication times, lattice structures, which are used as infilling materials within hollow parts, offer an effective solution for decreasing the high costs that currently impede the wider application of SLM in various industries. The assessment of mechanical properties of SLM-built lattice structures, however, remain challenging due to their complicated geometries, while pursuing experimental studies proves to be time-consuming due to the requirement of numerous part fabrication and physical testing. To address these research challenges, this study proposes an analytical modelling approach conducting quasi-static analysis on Ti6Al4V (Ti64) lattice structures. In order to investigate the structures’ mechanical properties, dynamic balance equation of the structures under compression loads were first established, and the stress distribution of the structures was calculated explicitly using central difference method. The modelling approach was validated by conducting uniaxial compression tests on samples fabricated using SLM. The experiments showed that the equivalent elastic modulus (E*) and the ultimate stress (UTS) values of the Ti64 structures predicted by the analytical method were in good agreement with the experimental results. The paper also discusses the design principles of SLM-built lattice structures (mainly the selection of proper topologies and relative densities) and examines the necessity and flexibility of the proposed analytical approach compared with conventional theoretical methods and their experimental studies in the context of SLM process.

Efficient protein targeting to the inner nuclear membrane requires Atlastin-dependent maintenance of ER topology.

Newly synthesized membrane proteins are targeted to the inner nuclear membrane (INM) by diffusion within the membrane system of the endoplasmic reticulum (ER), translocation through nuclear pore complexes (NPCs) and retention on nuclear partners. Using a visual in vitro assay we previously showed that efficient protein targeting to the INM depends on nucleotide hydrolysis. We now reveal that INM targeting is GTP-dependent. Exploiting in vitro reconstitution and in vivo analysis of INM targeting, we establish that Atlastins, membrane-bound GTPases of the ER, sustain the efficient targeting of proteins to the INM by their continued activity in preserving ER topology. When ER topology is altered, the long-range diffusional exchange of proteins in the ER network and targeting efficiency to the INM are diminished. Highlighting the general importance of proper ER topology, we show that Atlastins also influence NPC biogenesis and timely exit of secretory cargo from the ER.

FasTFit: A fast T-spline fitting algorithm

T-spline has been recently developed to represent objects of arbitrary shapes using a smaller number of control points than the conventional NURBS or B-spline representations in computer aided design, computer graphics, and reverse engineering. However, existing methods for fitting a T-spline over a point cloud are slow. By shifting away from the conventional iterative fit-and-refine paradigm, we present a novel split-connect-fit algorithm to more efficiently perform the T-spline fitting. Through adaptively dividing a point cloud into a set of B-spline patches, we first discover a proper topology of T-spline control points, i.e., the T-mesh. We then connect these B-spline patches into a single T-spline surface with different continuity options between neighboring patches according to the data. The T-spline control points are initialized from their correspondences in the B-spline patches, which are refined by using a conjugate gradient method. In experiments using several types of large-sized point clouds, we demonstrate that our algorithm is at least an order of magnitude faster than state-of-the-art algorithms while provides comparable or better results in terms of quality and conciseness.