Block Codes Research Articles

Analysis of Capacity of the Improved Space-Time Block Code Based on MIMO System

Analysis of Capacity of the Improved Space-Time Block Code Based on MIMO System

Morphological Transitions of Block Copolymer Micelles: Implications for Mesoporous Materials Ordering

AbstractThe design of block‐copolymer‐based functional materials, including mesoporous membranes and nanoparticles, requires a comprehensive understanding of the hierarchical assembly of block copolymers in selective solvents into micelles and subsequent ordered phases. It is hypothesized that micellar ordering and characteristic assembly can be described using a set of phase parameters that account for entropic and enthalpic interactions. Dissipative particle dynamics (DPD) simulations are used to systematically investigate the self‐assembly of semidiluted block copolymers, resembling isoporous membrane preparation conditions. The effect of Flory–Huggins interaction parameters, block lengths, and concentration on the morphology and polydispersity of the micelles is evaluated. The interaction parameters are mapped into Flory–Huggins theory by considering the block's conformation. These results reveal the effect of polymer concentration and solvent affinity on the morphological transition of the aggregates, in agreement with existing experimental evidence. It is identified that monodisperse‐spherical micelles in solution are fundamental to stabilize ordered states. Weak solvent segregation of the largest block, curvature of the core‐corona interface, and stretching of the corona‐forming one are found to be key to stabilize monodisperse assemblies. These conditions can be predicted using spherical‐micelles packing considerations and a global phase parameter from the Flory–Huggins theory. This study provides valuable insights into the self‐assembly of diblock copolymers and offers a potential way to optimize the preparation of mesoporous ordered structures and micelle ordering in semidiluted systems.

Decoding of MDP Convolutional Codes over the Erasure Channel under Linear Systems Point of View

This paper attempts to highlight the decoding capabilities of MDP convolutional codes over the erasure channel by defining them as discrete linear dynamical systems, with which the controllability property and the observability characteristics of linear system theory can be applied, in particular those of output observability, easily described using matrix language. Those are viewed against the decoding capabilities of MDS block codes over the same channel. Not only is the time complexity better but the decoding capabilities are also increased with this approach because convolutional codes are more flexible in handling variable-length data streams than block codes, where they are fixed-length and less adaptable to varying data lengths without padding or other adjustments.

Non-unitary Trotter circuits for imaginary time evolution

We propose an imaginary time equivalent of the well-established Pauli gadget primitive for Trotter-decomposed real time evolution, using mid-circuit measurements on a single ancilla qubit. Imaginary time evolution (ITE) is widely used for obtaining the ground state (GS) of a system on classical hardware, computing thermal averages, and as a component of quantum algorithms that perform non-unitary evolution. Near-term implementations on quantum hardware rely on heuristics, compromising their accuracy. As a result, there is growing interest in the development of more natively quantum algorithms. Since it is not possible to implement a non-unitary gate deterministically, we resort to the implementation of probabilistic ITE (PITE) algorithms, which rely on a unitary quantum circuit to simulate a block encoding of the ITE operator—that is, they rely on successful ancillary measurements to evolve the system non-unitarily. Compared with previous PITE proposals, the suggested block encoding in this paper results in shorter circuits and is simpler to implement, requiring only a slight modification of the Pauli gadget primitive. This scheme was tested on the transverse Ising model and the fermionic Hubbard model and is demonstrated to converge to the GS of the system.

Tailoring Silk Sericin Grafting: Comparing One‐Step and Two‐Step Approaches for PNIPAM/PAMPS Block Nanoparticles

AbstractStructurally defined, protein‐grafted nanoparticles are widely used in various biomedical applications, particularly as intelligent nanocarriers for drug delivery. The integration of synthetic polymers with natural proteins such as silk sericin enhances the functionality and stability of these nanocarriers, making them suitable for targeted and controlled drug release. In this context, an optimized grafting procedure for silk sericin is presented, employing a protein macroinitiator and atom transfer radical polymerization (ATRP). This study aims to elucidate the significance of the grafting process in tailoring the structure of sericin through the chemistry of synthetic grafts. The grafting procedure uses block copolymers of N‐isopropylacrylamide (NIPAM) and 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS), such as Poly‐(AMPS‐block‐NIPAM)/Poly‐(NIPAM‐block‐AMPS). The procedure employs both one‐step and two‐step synthesis methods to produce a well‐defined, biofunctionalized sericin. Subsequently, sericin‐based nanoparticles are prepared, demonstrating the significance of the optimized procedure. The synthesized products undergo structural analysis using H‐NMR, FTIR‐ATR, XPS, DLS, and zeta potential measurements. In addition, their thermal behavior is assessed using differential scanning calorimetry. To further investigate the prepared nanoparticles, SEM and DLS analyses are conducted. Through synthesis optimization, position and length of each synthetic block is precisely determined, significantly influencing properties of the grafted products and characteristics of the resulting nanoparticles.

PDMS-based copolymers with polyurea blocks and 1,2,3-triazole blocks obtained by CuAAC polymerization for 3D printing

Polydimethylsiloxanes with improved mechanical properties that can be processed by 3D printing are in high demand for scientific and practical applications. In our article, we proposed the synthesis of new PDMS copolymers with urethane and triazole fragments using the CuAAC reaction mechanism, as well as 3D printing with the obtained copolymers. Two types of copolymers, with molecular weights of 3000 and 6000 Da of PDMS block length, were prepared and characterized by GPC, IR spectroscopy, TGA, DSC, TMA, SAXS, and rheological measurements to determine their physicochemical properties. The synthesized copolymers were found to be suitable for processing by extrusion 3D printing. This demonstrated the ability to 3D print macroscale models of varying shapes and complexity. The resulting materials retained their printed shape over time.

Method for determining the types of encryption of linear block codes

Problem statement. All known methods for determining the parameters of the encrypted code are based on known types of channel encoding and encryption, but the scrambling code data received by the uncoordinated communication parties is unknown, therefore it is necessary to analyze whether the outgoing signal is encoded, and which encryption method is adopted, contributing to further parameter determination. Goal. Development of a methodology for determining the types of encryption of linear block codes by combining correlation features and convolutional neural networks. Results. The simulation results show that compared with the traditional feature detection method, this method, based on a convolutional neural network and long short-term memory, has a better recognition speed at BER and can recognize the type of encryption of linear block code in BER and noise conditions. Practical significance. The identification of the encryption code parameters is used to subsequently determine the parameters of the encoder and has significant practical engineering value. The work was carried out with the financial support of the Ministry of Science and Higher Education of the Russian Federation within the framework of the state assignment "youth laboratory" No. FZGM-2024-0003.

Microstructure and mechanical properties of a statistical aromatic-aliphatic copolyester synthesized by catalytic transesterification

Copolymerising polyethylene terephthalate (PET) and polycaprolactone (PCL) could provide a cost-effective method to recycle PET waste into a compostable plastic. In this work we investigated the relationship between formulation, microstructure, and mechanical properties during catalytic transesterification. It was found that the wt.% PCL was most effective in reducing the average PET block length and determining the copolymer's microstructure at equilibrium. Catalytic transesterification is a random process and can only give a narrow distribution when the average homopolymer block length is less than three, as determined by 1H NMR spectroscopy. A statistical copolymer marks reaction equilibrium where the average PCL block length is greater than one, contradicting the theoretical limit of a single PCL block length. It was proposed that the number of PCL ester groups available for reaction diminishes as transesterification progresses, leading to a favouring of the more abundant PET ester groups to undergo neutral or reverse reactions, resulting in equilibrium. As a result of the imbalance in the availability of PET and PCL ester groups at equilibrium, secondary factors, such as increasing the catalyst amount, were ineffective in further propagating transesterification. Copolymers formed in this study were either amorphous or semi-crystalline. The mechanical properties had minimal correlation with crystallinity and instead was mainly influenced by the ratio between the “hard” (PET) and “soft” (PCL and copolymer) segments in the microstructure and the molecular mass. In this study it was demonstrated that the microstructure of aromatic-aliphatic copolymers, synthesized through catalytic transesterification, can be manipulated to tailor physical properties to meet application requirements.

Freshness-in-air: An AoI-inspired UAV-assisted wireless sensor networks

The Age-of-Information (AoI) metric has emerged as a performance measurement metric for evaluating time-sensitive wireless communications systems. Maintaining the freshness and reliability of data is critical in time-critical wireless networks, where outdated information can have significant consequences. Moreover, short packet transmissions are used in wireless sensor networks (WSNs) to maintain energy efficiency and low latency. This paper proposes a theoretical model that utilizes the AoI metric and finite block length information theory to estimate information freshness in an unmanned aerial vehicle (UAV)-assisted WSN. This network includes multiple sensing nodes and relies on short-packet communication for transmission. In this paper, closed-form expressions for average AoI (AAoI) and the block error rate are derived. Furthermore, the optimal altitude and block length that ensures the freshness of received information at the destination is determined. The results of the analysis provide valuable insights into the performance characteristics of UAV-assisted WSNs and have important implications for the design and optimization of such systems.

Impact of Block Coding on Age of Information in Centralized IoT: Insights From BEC and BSC

Impact of Block Coding on Age of Information in Centralized IoT: Insights From BEC and BSC

STATISTICAL PROPERTIES OF THE PSEUDORANDOM SEQUENCE GENERATION ALGORITHM

One of the most important issues in the design of cryptographic algorithms is studying their cryptographic strength. Among the factors determining the reliability of cryptographic algorithms, a good pseudorandom sequence generator, which is used for key generation, holds particular significance. The main goal of this work is to verify the normal distribution of pseudorandom sequences obtained using the generation algorithm and demonstrate that there is no mutual statistical correlation between the values of the resulting sequence. If these requirements are met, we will consider such a generator reliable. This article describes the pseudorandom sequence generation algorithm and outlines the steps for each operation involved in this algorithm. To verify the properties of the pseudorandom sequence generated by the proposed algorithm, it was programmatically implemented in the Microsoft Visual C++ integrated development environment. To assess the statistical security of the pseudorandom sequence generation algorithm, 1000 files with a block length of 10000 bits and an initial data length of 256 bits were selected. Statistical analysis was conducted using tests by D. Knuth and NIST. As shown in the works of researchers, the pseudorandom sequence generation algorithm, verified by these tests, can be considered among the reliable algorithms. The results of each graphical test by D. Knuth are presented separately. The graphical tests were evaluated using values obtained from each test, while the chi-squared criterion with degrees of freedom was used to analyze the evaluation tests. The success or failure of the test was determined using a program developed by the Information Security Laboratory. Analysis of the data from the D. Knuth tests showed good results. In the NIST tests, the P-value for the selected sequence was calculated, and corresponding evaluations were made. The output data obtained from the NIST tests also showed very good results. The proposed pseudorandom sequence generation algorithm allows generating and selecting a high-quality pseudorandom sequence of a specified length for use in the field of information security.

3D‐Printed Carbon Nanoneedle Electrodes for Dopamine Detection in Drosophila

AbstractIn vivo electrochemistry in small brain regions or synapses requires nanoelectrodes with long straight tips for submicron scale measurements. Nanoelectrodes can be fabricated using a Nanoscribe two‐photon printer, but annealed tips curl if they are long and thin. We propose a new pulling‐force strategy to fabricate a straight carbon nanoneedle structure. A micron‐width bridge is printed between two blocks. The annealed structure shrinks during pyrolysis, and the blocks create a pulling force to form a long, thin, and straight carbon bridge. Parameterization study and COMSOL modeling indicate changes in the block size, bridge size and length affect the pulling force and bridge shrinkage. Electrodes were printed on niobium wires, insulated with aluminum oxide, and the bridge cut with focused ion beam (FIB) to expose the nanoneedle tip. Annealed needle diameters ranged from 400 nm to 5.25 μm and length varied from 50.5 μm to 146 μm. The electrochemical properties are similar to glassy carbon, with good performance for dopamine detection with fast‐scan cyclic voltammetry. Nanoelectrodes enable biological applications, such as dopamine detection in a specific Drosophila brain region. Long and thin nanoneedles are generally useful for other applications such as cellular sensing, drug delivery, or gas sensing.

3D-Printed Carbon Nanoneedle Electrodes for Dopamine Detection in Drosophila.

In vivo electrochemistry in small brain regions or synapses requires nanoelectrodes with long straight tips for submicron scale measurements. Nanoelectrodes can be fabricated using a Nanoscribe two-photon printer, but annealed tips curl if they are long and thin. We propose a new pulling-force strategy to fabricate a straight carbon nanoneedle structure. A micron-width bridge is printed between two blocks. The annealed structure shrinks during pyrolysis, and the blocks create a pulling force to form a long, thin, and straight carbon bridge. Parameterization study and COMSOL modeling indicate changes in the block size, bridge size and length affect the pulling force and bridge shrinkage. Electrodes were printed on niobium wires, insulated with aluminum oxide, and the bridge cut with focused ion beam (FIB) to expose the nanoneedle tip. Annealed needle diameters ranged from 400 nm to 5.25 μm and length varied from 50.5 μm to 146 μm. The electrochemical properties are similar to glassy carbon, with good performance for dopamine detection with fast-scan cyclic voltammetry. Nanoelectrodes enable biological applications, such as dopamine detection in a specific Drosophila brain region. Long and thin nanoneedles are generally useful for other applications such as cellular sensing, drug delivery, or gas sensing.

Аналіз технологій реконфігурації систем інтернету речей на рівні програмних модулів та завантажувачів

The subject of study and research in this article are the technology of programming and interaction of nodes, as well as individual small-sized components of embedded Internet of Things (IoT) systems. The goal is to increase the flexibility of IoT system components by simplifying the reconfiguration process of individual nodes and components. The task is: to analyze existing approaches to building configurable systems, analyze and describe existing solutions that implement joint approaches; to analyze the tools for implementing the selected approaches; to describe the method of building a living system based on the analysis approach; and to provide a technical example of the proposed programming method. According to the tasks, the following results were obtained. Possible ways of reconfiguration of IoT components are analyzed. Methods of reconfiguration at the network level and partial node reconfiguration are considered. Methods to ensure the flexibility of IoT components are analyzed and classified. A comparative analysis of the summary parameters of the loaders was carried out. The possibility of using software components as immutable blocks of code to modify the microcontroller program as a method of reconfiguration was analyzed. The idea of using variable software modules to represent the microcontroller program at a higher level of abstraction with a modified bootloader is thus proposed. Elements of a method for reprogramming variable software modules of microcontrollers as middleware are proposed. Conclusions. According to a review of the existing types of systems, they were classified according to the level of organization of their reconfigured parts. According to the obtained preliminary classifications, some architectural solutions were considered from the point of view of improving operational characteristics. The main advantages for each type of organization of the reconfigurable parts of the systems are highlighted. An analysis of practical solutions regarding the modification of the built-in components of microcontrollers for managing and updating their firmware was conducted. The practical significance of this study is the proposal of a method of programming with variable software modules for microcontrollers and the obtained results of a competitive analysis of methods of modifying components and loader characteristics.

Design and Test of a Crawler-Type On-Film Precision Cotton Seeding Device on DEM-CFD

To solve the limitation of speed in the operation of air-suction cotton precision seeding devices, a new crawler-type precision on-film seeding device was designed using an extended duckbill hole-forming device to produce hole-forming belts and lateral seed collection. Coupling simulation of seeding, and analysis of drag force and movement speed of cotton seeds were conducted on EDEM-CFD. A mechanical model of the operation was established, and the effects of the suction hole diameter, pressure relief block length, and wind pressure on seeding performance were analyzed. Regression models between influencing factors and seeding performance indices were established using response surface methodology. The test data were analyzed using Design Expert 10.0.3. The influence rules for each factor on seeding performance were established. The factors affecting the seeding qualified index exhibited the following order: air pressure > pressure relief block length > suction hole diameter. The optimization goals included defining the maximum value of a qualified single-seed index and the minimum value of the missing index, and the best parameter combination was obtained based on a suction hole diameter of 3.624 mm, pressure relief block length of 63.369 mm, and wind pressure of 3.797 kPa. According to the actual test conditions, the parameters were revised to include a suction hole diameter of 3.6 mm, a relief block length of 63.4 mm, and wind (air) pressure of 3.8 kPa for verification tests. The actual qualified single-seed index is 94.87% ± 0.98 %, the missing index is 1.45% ± 0.32%, and the multiple index is 3.68% ± 0.62%. The difference from the predicted value is within 5%, indicating that this study can provide a reference for the structural design and optimization of crawler-type on-film precision cotton seeding devices.

Gender-related differences in kinematic parameters of the start and performance in a 50m breaststroke swimming

Introduction: In swimming, the competitions are divided by age categories, with each swimming event beginning at the start. For optimal improvements in swimming performance in the sprint events, the performance at the start and during swimming in each age category should be analyzed. Aim: The aim of our study is to show the differences in kinematic parameters of the start and performance in the sprint event of 50 m breaststroke from the perspective of gender in different age groups at international competitions organized in Slovakia. Materials and Methods: The females were categorized by age into K3 (2010-2011; n=36; 282 WA points), K2 (2008-2009; n=26; 409 WA points) and K1 (2007 and older; n=34; 503 WA points) groups. Males were categorized into K3 (2009-2010; n=27; 265 WA points), K2 (2007-2008; n=33; 372 WA points) and K1 (2006 and older; n=39; 207 WA points) groups. We used SwimPro cameras and Dartgish software to monitor kinematic parameters in the above-water, underwater, and swim phases. The parameters monitored were block time (BT), time (FT), and length (FD) of flight, time (UWT) and length (UWD) underwater, swim time (ST) and distance (SD) to 15 m, time to 15 m (T15), 25 m (T25), and 50 m (T50) distance. Data were tested by Shapiro-Wilk, Kruskal-Wallis ANOVA, and Mann-Whitney U test in Statistica software (version 13.5). Results: Statistically significant differences (p<0.01) in females were found in the above-water phase in BT, FT, and FD between K3 and K1. The underwater phase in UWT showed differences between K3 to K1, K2 to K1 whereas for UWD - between K3 and K2 and between K2 and K1. For T15 and T25, there were differences (p<0.01) between all categories, but in the final time (T50), the differences occurred between K3 and K2 and between K3 and K1. In males, there was a significant difference in the above-water phase between K3 and K1 and between K2 and K1. In UWD, ST, SD, T15, T25, and T50, there were significant differences between all categories. Differences (p>0.01) between males and females by category in the above-water phase were measured in FT (K1) and FD (K2, K1). In the underwater phase, the differences were found in UWT (K2) and UWD (K1). For T15, T25, and T50, significant differences were shown in all categories. Conclusions: The kinematic analysis revealed differences not only in the start phases and the 50 m breaststroke swimming in the male and female categories but also between genders. Differences in swimming performance may be due to performance at the start and therefore more attention should be paid to the start phases in the different categories of swimmers.

Rational design of diblock copolymer enables efficient cytosolic protein delivery

Polymer-mediated cytosolic protein delivery demonstrates a promising strategy for the development of protein therapeutics. Here, we propose a new designed diblock copolymer which realizes efficient cytosolic protein delivery both in vitro and in vivo. The polymer contains one protein-binding block composed of phenylboronic acid (PBA) and N-(3-dimethylaminopropyl) (DMAP) pendant units for protein binding and endosomal escape, respectively, followed by the response to ATP enriched in the cytosol which triggers the protein release. The other block is PEG designed to improve particle size control and circulation in vivo. By optimizing the block composition, sequence and length of the copolymer, the optimal one (BP20) was identified with the binding block containing 20 units of both PBA and DMAP, randomly distributed along the chain. When mixed with proteins, the BP20 forms stable nanoparticles and mediates efficient cytosolic delivery of a wide range of proteins including enzymes, toxic proteins and CRISPR/Cas9 ribonucleoproteins (RNP), to various cell lines. The PEG block, especially when further modified with folic acid (FA), enables tumor-targeted delivery of Saporin in vivo, which significantly suppresses the tumor growth. Our results shall inspire the design of novel polymeric vehicles with robust capability for cytosolic protein delivery, which holds great potential for both biological research and therapeutic applications.

Role of Unimers to Polymersomes Transition in Pluronic Blends for Controlled and Designated Drug Conveyance.

This study investigates the nanoscale self-assembly from mixtures of two symmetrical poly(ethylene oxide)-poly(propylene oxide)-pol(ethylene oxide) (PEO-PPO-PEO) block copolymers (BCPs) with different lengths of PEO blocks and similar PPO blocks. The blended BCPs (commercially known as Pluronic F88 and L81, with 80 and 10% PEO, respectively) exhibited rich phase behavior in an aqueous solution. The relative viscosity (ηrel) indicated significant variations in the flow behavior, ranging from fluidic to viscous, thereby suggesting a possible micellar growth or morphological transition. The tensiometric experiments provided insight into the intermolecular hydrophobic interactions at the liquid-air interface favoring the surface activity of mixed-system micellization. Dynamic light scattering (DLS) and small-angle neutron scattering (SANS) revealed the varied structural morphologies of these core-shell mixed micelles and polymersomes formed under different conditions. At a concentration of ≤5% w/v, Pluronic F88 exists as molecularly dissolved unimers or Gaussian chains. However, the addition of the very hydrophobic Pluronic L81, even at a much lower (<0.2%) concentration, induced micellization and promoted micellar growth/transition. These results were further substantiated through molecular dynamics (MD) simulations, employing a readily transferable coarse-grained (CG) molecular model grounded in the MARTINI force field with density and solvent-accessible surface area (SASA) profiles. These findings proved that F88 underwent micellar growth/transition in the presence of L81. Furthermore, the potential use of these Pluronic mixed micelles as nanocarriers for the anticancer drug quercetin (QCT) was explored. The spectral analysis provided insight into the enhanced solubility of QCT through the assessment of the standard free energy of solubilization (ΔG°), drug-loading efficiency (DL%), encapsulation efficiency (EE%), and partition coefficient (P). A detailed optimization of the drug release kinetics was presented by employing various kinetic models. The [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] MTT assay, a frequently used technique for assessing cytotoxicity in anticancer research, was used to gauge the effectiveness of these QCT-loaded mixed nanoaggregates.

Synthesis and Electron Transporting Properties of Diblock Copolymers Consisting of Polyfluorene and Polystyrene.

Poly(9,9-di-n-octylfluorene) (PFO) is a promising material for polymer light-emitting diodes (PLEDs) due to its advantageous properties. To enhance its electron transporting capabilities, diblock polymers were synthesized by attaching polystyrene (PSt) chains of varying lengths to one end of the PFO molecule. In a comparative study with PFO homopolymer, the diblock polymers maintained similar thermal properties, absorption spectra, and photoluminescent stability, while exhibiting slightly deeper lowest unoccupied molecular orbital (LUMO) levels and higher crystallinity. Notably, diblock polymers with shorter polystyrene blocks demonstrated higher electron mobility than the PFO homopolymer and diblock polymers with excessively long polystyrene blocks. These findings suggest that the optimal chain length of the polystyrene block is crucial for maximizing electron mobility, thus offering valuable insights for designing high-performance PLED materials.

A new efficient decoder of linear block codes based on ensemble learning models: case of boosting

&lt;p&gt;Error-correcting codes are used to partially or completely correct errors as much as possible, while ensuring high transmission speeds. Several Machine Learning (ML) models such as Logistic Regression and Decision tree have been applied to correct transmission errors. Among the most powerful ML techniques are aggregation methods which have yielded to excellent results in many areas of research. It is this excellence that has prompted us to consider their application for the hard decoding problem. In this sense, we have successfully designed, tested and validated our proposed EL-BoostDec decoder (hard decision decoder based on Ensemble Learning - Boosting technique) which is based on computing of the syndrome of the received word and on using Ensemble Learning techniques to find the corresponding corrigible error. The obtained results with EL-BoostDec are very encouraging in terms of the binary error rate (BER) that it offers. Practically EL-BoostDec has succeed to correct 100% of errors that have weights less than or equal to the correction capacity of studied codes. The comparison of EL-BoostDec with many competitors proves its power. A study of parameters which impact on EL-BoostDec performances has been established to obtain a good BER with minimum run time complexity.&lt;/p&gt;