Consecutive Blocks Research Articles

Waring’s Theorem for Binary Powers

A natural number is a binary k’ th power if its binary representation consists of k consecutive identical blocks. We prove, using tools from combinatorics, linear algebra, and number theory, an analogue of Waring’s theorem for sums of binary k’th powers. More precisely, we show that for each integer k> 2, there exists an effectively computable natural number n such that every sufficiently large multiple of Ek:=gcd(2k - 1,k) is the sum of at most n binary k’th powers. (The hypothesis of being a multiple of Ek cannot be omitted, since we show that the gcd of the binary k’th powers is Ek.) Furthermore, we show that n = 2O(k3). Analogous results hold for arbitrary integer bases b>2.

CFO/Channel estimation algorithms for space‐time block coded orthogonal frequency division multiplexing wireless relay networks without using cyclic prefix of OFDM

This study presents a simple technique, which is used to estimate both channel state and carrier frequency offset (CFO) in decode-and-forward relay systems, where coded orthogonal frequency division multiplexing is employed without cyclic prefix. On the basis of the least-square criterion, we derive the estimate of CFO and channel with the aids of consecutive blocks of pilot symbols. The initially proposed estimation technique achieves a distinguished performance by using a two-dimensional complete search approach; however, the computation becomes more and more intensive when the search granularity becomes finer and finer. For this reason, we further present an iterative approach as an alternative solution, which provides a performance comparable with that of the complete search method, while greatly reducing the implementation complexity. Besides, we also derive a closed-form expression of the CFO estimate for the considered system, which allows us to avoid the exhaustive search during the estimation processing. Computer simulations have been conducted to verify the efficiency of the proposed schemes.

Analysis of the Time-Frequency Localization Property of the Filter Banks for Optical OFDM/OQAM Systems

Orthogonal frequency-division multiplexing offset-quadrature amplitude modulation (OFDM/OQAM) relaxes the orthogonal condition from the complex domain to the real field. Therefore, the cyclic prefix (CP) inserted between consecutive optical OFDM blocks, for combating the inter-symbol interference (ISI) induced by chromatic dispersion (CD) and polarization-mode-dispersion (PMD), could be removed for optical OFDM/OQAM to promote the system spectral efficiency. The ISI and the inter-carrier-interference (ICI) could be combated by using the filter banks with good time-frequency localization (TFL) property. Thus, the accuracy of channel estimation and system transmission performance largely depend on the TFL property of the filter banks for optical OFDM/OQAM. Recently, numerical experimental demonstrations and theoretical discussions of optical OFDM/OQAM have been reported. However, to our best knowledge, discussions on the TFL property of the filter banks have not been studied for optical OFDM/OQAM to date. In this paper, we systematically analyze the TFL property of the filter banks for optical OFDM/OQAM for the first time. We evaluate the TFL property of the filter banks with energy concentration, orthogonal basis, and isotropic property. Three typical filters as the Gaussian filter, the extended Gaussian function (EGF) filter and the isotropic orthogonal transfer algorithm (IOTA) filter have been employed for comparison. According to our theoretical analysis, with the use of the IOTA filter, optical impairments and channel estimation complexities could be decreased evidently thanks to the promising isotropic property. As shown in the numerous Montel Carlo simulations of the coherent optical OFDM/OQAM, system robustness against IMI, phase noise induced interference (PNII) and nonlinear effect could be improved evidently with the use of the IOTA filter.

Parallel implementation of empirical mode decomposition for nearly bandlimited signals via polyphase representation

Nearly bandlimited signals play an important role in the biomedical signal processing community. The common method to analyze these signals is via the empirical mode decomposition approach which decomposes the non-stationary signals into the sums of the intrinsic mode functions. However, this method is computational demanding. A natural idea to reduce the computational cost is via the block processing. However, the severe boundary effect would happen due to the discontinuities between two consecutive blocks. In order to solve this problem, this paper proposes to realize the parallel implementation via polyphase representation. That is, the empirical mode decomposition is implemented on each polyphase component of the original signal. Then each sub-signals are combined after upsampling. The simulation results show that our proposed method achieves the approximate intrinsic mode functions both qualitatively and quantitatively very close to the true intrinsic mode functions. Besides, compared with the conventional block processing method which significantly suffered from the boundary effect problem, our proposed method does not have this issue.

Analysis and design of a DC to 18 GHz 6-bit attenuator with simultaneous phase and gain error correction

In this paper the design of a digital step attenuator with simultaneous low phase and gain error characteristics is investigated. First, the loading effect of the consecutive blocks of an N-bit attenuator on the precision of the attenuation levels is analyzed. Then a modified structure to decrease the loading effect as well as the phase error of the attenuator blocks is presented. A comprehensive analysis of the circuit is performed and some design guidelines have described. Finally, a 6-bit attenuator with attenuation range of 0.5–31.5 dB and resolution of 0.5 dB is implemented in 0.18 µm complementary metal–oxide-semiconductor (CMOS) technology. The root mean square (RMS) gain error and RMS phase error of the designed circuit for different process corners and DC to 18 GHz are below 0.59 dB and 4.2°, respectively.

Usefulness of Trends in Continuous Electrocardiographic Telemetry Monitoring to Predict In-Hospital Cardiac Arrest

Survival from in-hospital cardiac arrest (IHCA) due to pulseless electrical activity/asystole remains poor. We aimed to evaluate whether electrocardiographic changes provide predictive information for risk of IHCA from pulseless electrical activity/asystole. We conducted a retrospective case-control study, utilizing continuous electrocardiographic data from case and control patients. We selected 3 consecutive 3-hour blocks (block 3, 2, and 1 in that order); block 1 immediately preceded cardiac arrest in cases, whereas block 1 was chosen at random in controls. In each block, we measured dominant positive and negative trends in electrocardiographic parameters, evaluated for arrhythmias, and compared these between consecutive blocks. We created random forest and logistic regression models, and tested them on differentiating case versus control patients (case block 1 vs control block 1), and temporal relation to cardiac arrest (case block 2 vs case block 1). Ninety-one cases (age 63.0 ± 17.6, 58% male) and 1,783 control patients (age 63.5 ± 14.8, 67% male) were evaluated. We found significant differences in electrocardiographic trends between case and control block 1, particularly in QRS duration, QTc, RR, and ST. New episodes of atrial fibrillation and bradyarrhythmias were more common before IHCA. The optimal model was the random forest, achieving an area under the curve of 0.829, 63.2% sensitivity, 94.6% specificity at differentiating case versus control block 1 on a validation set, and area under the curve 0.954, 91.2% sensitivity, 83.5% specificity at differentiating case block 1 versus case block 2. In conclusion, trends in electrocardiographic parameters during the 3-hour window immediately preceding IHCA differ significantly from other time periods, and provide robust predictive information.

Clinical Debrief: learning and well-being together.

SummaryBackgroundClinical environments can be so stressful to medical students as to be detrimental to their learning and well‐being. Our intervention, Clinical Debrief, integrates learning through clinical experience with the development of positive coping strategies. Students shared cases and experiences during weekly small group classroom discussions, facilitated by general practitioners (from outside their current hospital placement), throughout two consecutive 12‐week blocks of their first clinical year. Alongside enquiry‐based and clinical reasoning learning, we gave students a safe space to reflect on their affect. Our aim was to critically examine students’ views in Clinical Debrief.MethodAnonymised quantitative and qualitative evaluation data were collected over 3 years using online questionnaires on completion of each 12‐week block. The data relating to psychological supervision were analysed independently and in parallel, using thematic analysis for qualitative data.We aim to help students develop positive coping mechanisms, promoting empathy,self‐awarenessand wellbeingResultsA total of 1857 evaluations were extracted (response rate 67%). The median (interquartile range) overall rating for Clinical Debrief sessions was 9 (8–10), where 10 indicates ‘excellent’ and 1 indicates ‘significant improvement needed’. The rating for the supervisory aspects of the sessions and free‐text comments were positive. Students appreciated safe environments, the session structure, facilitator role modelling, transitional support and processing of emotional experiences.DiscussionMandatory integrated longitudinal supervision, using trained clinician facilitators, was positively received by students in transition to clinical placements. Normalising the emotional impact of medical work destigmatises distress. Linking clinical reasoning with affective state awareness to contextualise case management, following Mezirow's transformative learning theory, brings added benefit to learning and well‐being. Student demand for the expansion of Clinical Debrief is evidence of success.

Sympathetic blocks for complex regional pain syndrome: a survey of pain physicians

BackgroundSympathetic blocks (SB) are commonly used to treat pain from complex regional pain syndrome (CRPS). However, there are currently no guidelines to assist pain physicians in determining the best practices...

DNA Encoding and Channel Shuffling for Secured Encryption of Audio Data

Multimedia file like audio demands special encryption technique due to its large data capacity without compromising correlation between it’s original and encrypted version (closer to zero). Most of the popular block cipher techniques work on multiple rounds whereas the proposed scheme guarantees the necessary low correlation between the original and the encrypted file without multiple rounds. The unique feature is that the consecutive blocks use different keys derived from the original one using the proposed key chaining algorithm and experimental results show that the correlation between the consecutive keys is also close to zero. The used encryption technique is based on DNA encoding with logistic chaotic map using the generated chain of keys. Furthermore, the concept of channel shuffling is introduced to make the encrypted data more secure. The experimental results confirm that the correlation between the original and ciphered block is close to zero and number of samples change rate value is close to 100. Again correlation between the two consecutive ciphered blocks is also close to zero, which conforms the acceptability of proposed scheme.

IWT-MDE based reversible thermal image watermarking enhanced with secret sharing mechanism

Telemedicine systems are used to transfer medical images between hospitals and doctors for consultation in many countries recently. It is crucial to ensure integrity of medical images transferred on unencrypted channels. Many medical image watermarking techniques have been proposed in the literature to deal with this problem. Thermal imaging to detect dense vascular regions is a new medical imaging modality gaining popularity to enhance diagnosis of breast cancer. Thermal images with large smooth areas and Region of Interest (ROI) have different characteristics compared to traditional medical images and require new image watermarking methods. A new thermal image watermarking algorithm utilizing Integer Wavelet Transform (IWT), Modified Difference Expansion (MDE) and Shamir’s Secret Sharing Scheme (SSSS) has been proposed for e-healthcare applications in this paper. IWT coefficients of thermal image are expanded by the MDE to make more consecutive blocks expandable. Location Map (LM) becomes more compressible if there are many consecutive blocks. Thus, larger ROI can be watermarked by the proposed method. The method also uses SSSS to share LM into meaningless shares embedded into border regions. Sharing LM by the SSSS makes it possible to reconstruct it even if some of the thermal image borders are removed inadvertently or modified on purpose to break the watermark. Experimental results indicate that the proposed method has better embedding capacity and good imperceptibility compared to similar methods reported in the literature. Besides, it has expanded ROI size and also is the first method which considers border region attacks in medical image watermarking.

Optimal control strategies for hollow core ventilated slab systems

This paper evaluated potential operational cost savings associated with optimal control strategies for hollow core ventilated slab systems used to maintain indoor thermal comfort for office buildings. First, a simplified calculation method was developed to convert two-dimensional (2D) modeling of ventilated slab thermal performance to one-dimensional (1D) analysis in order to reduce computational efforts required for optimization search while maintaining acceptable accuracy level. The total energy costs were considered to identify optimal control strategies to operate ventilated slab systems to cool and heat office spaces. Penalty functions restricted the optimization search to ensure that indoor thermal comfort was maintained during occupancy periods. Then, the consecutive time block optimization (CTBO) technique was used with a genetic algorithm (GA) based search method to identify strategies that minimize the operational costs of the ventilated slab systems. A comparative analysis was carried out to evaluate the impact of ventilated slab systems’ design properties on the optimal operational cost savings. The results of the optimization analysis showed that the proposed optimal controller can achieve up to 11% cost savings to operate ventilated slab systems.

Learning autonomy, digital learners and Google Education: a rhizomatic English syllabus framework

<p>Exploiting the free technology empowering services with which Google supplies the educational field, the present paper contributes a Google Education mediated syllabus framework to the field of teaching English as a second/ foreign language. Through a systems approach methodology, the framework addressed the concepts of ‘learner autonomy’ and ‘digital learners’ within the scope of its consecutive blocks: conceptualisation, planning and development. The relevance of this effort is to be seen in terms of bridging the ever-growing gap between the classroom and the digital world of web 2.0 learners; as well as enabling the teachers to contextualise the proposed tool with regard to their syllabi development, renewal and adaptation. </p>

Interfacial dynamics of immiscible binary fluids through ordered porous media: The interplay of thermal and electric fields

We report the interplay of electrical and thermal fields on the interfacial dynamics of two immiscible fluids inside a periodic porous domain. The alternating current electrothermal mechanism is employed to generate the two phase flow. The surfaces of the porous blocks are wetted with wettability conditions which are manifested by a predefined static contact angle. Depending on the surface affinity and the electrical parameters, two distinctive spatio-temporal regimes can be identified, namely, trapping of the displaced fluid between the two consecutive porous blocks (formation of liquid bridge) and merging of contact lines after traveling the obstacle (complete interface recovery). Results show that liquid bridge formation and complete interface recovery are strongly influenced by the viscosity and thermal conductivity contrasts, in addition to the relevant electro-thermal parameters.

Changes of median nerve conduction, cross-sectional area and mobility by radioulnar wrist compression intervention in patients with carpal tunnel syndrome

BackgroundOwing to the compressive nature of the neuropathy, patients with carpal tunnel syndrome (CTS) have prolonged distal motor latency (DML), sensory nerve latency (SNL), median nerve swelling and restricted median nerve mobility. The purpose of this study was to noninvasively augment carpal tunnel space using radioulnar wrist compression (RWC) and evaluate its effects on median nerve pathological properties in patients with CTS. It was hypothesized that the RWC intervention would reduce the median nerve DML, SNL and cross-sectional area (CSA) and enhance longitudinal median nerve mobility in patients. with CTS. MethodsEleven patients diagnosed with CTS participated in this study. A portable RWC intervention splint was developed to apply 10 N of compressive force across the wrist. Three daily sessions of RWC were performed over 4 weeks of intervention (15 min per session, 45 min per day, 7 days per week). Each 15-min session consisted of three 5-min blocks of RWC, with a 1-min rest in between consecutive blocks. Patients were evaluated at Week 0 (baseline), Week 2 (mid-intervention) and Week 4 (end of intervention). DML and SNL of the median nerve were evaluated using established nerve conduction study techniques. Median nerve CSA at the distal wrist crease was obtained by ultrasound imaging. Median nerve motion associated with finger flexion/extension was captured by dynamic ultrasound imaging and quantified using a speckle cross-correlation algorithm. Finger flexion/extension was recorded using an electrogoniometer. The slope of the regressed linear equation of median nerve displacement as a function of finger flexion angle was used to quantify nerve mobility. ResultsPatients with CTS showed significantly decreased DML (p = 0.048) and median nerve CSA (p < 0.001) and increased nerve mobility (p < 0.001) at mid-intervention compared to baseline. However, DML, CSA and mobility of the median nerve did not differ significantly between Weeks 2 and 4 (p = 0.574, 1.00 and 0.139, respectively). Median nerve SNL was not significantly affected throughout the 4-week intervention (p = 0.330 for Week 0 vs. 2; p = 1.00 for Week 2 vs. 4). ConclusionThis study revealed that RWC intervention with 10-N force applied to the wrist in the radioulnar direction could restore impaired neurophysiological and biomechanical functions of the median nerve. The beneficial effects of RWC intervention for the median nerve were in evidence after a relatively short period of two weeks. These functional improvements could be explained by intermittent decompression of the median nerve via RWC-induced augmentation of the carpal arch. The translational potential of this articleBiomechanically manipulating the carpal tunnel by RWC decompresses the median nerve and has the potential to become an alternative treatment for CTS.

Charting a successful course: The academic and clinical success committee's impact on student success.

The road from prematriculation to graduation looks different for each student at each institution. To successfully complete the curriculum, students must often overcome difficulties, both academic and nonacademic. Up to 15% of 3rd-year medical students in the United States are still struggling on the major components of their clerkships and 11% in their 4th year. While there is an established need for medical school remediation, there is little evidence supporting what specifically works across the board. These deficiencies often do not go away on their own and with the need to educate all students, the guidance provided by multiple stakeholders (i.e., administration, staff, faculty, and clinicians) would be necessary to chart a course of success for these students. The Academic and Clinical Success Committee (ACSC) at the Texas A and M University College of Medicine provides a venue to review individual students and provide input, resources, and support on a timely basis. This is a necessary ingredient in guiding the students facing academic and clinical challenges toward successful completion of graduation requirements. Since its incorporation, the work of the ACSC has contributed to a decrease in failures on consecutive block examinations, a decreased failure rate on Step 2 clinical skills (CS), and increased capacity to help students at risk of failing Step 1 to not do so. In this brief report, we illustrate how we developed the ACSC, the impact and levels of success it has had on students, and challenges we have faced.

Chronos+: An Accurate Blockchain-based Time-stamping Scheme for Cloud Storage

We propose Chronos $^{{\mathbf +}}$ + , an accurate blockchain-based time-stamping scheme for outsourced data, where both the storage and time-stamping services are provided by cloud service providers. Specifically, Chronos $^{{\mathbf +}}$ + integrates a file into a transaction on a blockchain once the file is created, which guarantees the file's latest creation time to be the time when the block containing the transaction is appended to the blockchain. A sufficient number of consecutive blocks that are latest confirmed on the blockchain is embedded into the file at the creation time. These blocks serve as a time-dependent random seed to prove the earliest creation time, due to blockchains’ chain quality property. Chronos $^{{\mathbf +}}$ + makes the file's timestamp corresponding to a time interval formed by the earliest and latest creation times which are derived from the heights of the corresponding blocks. Due to blockchains’ chain growth property, such a height-derived timestamp can ensure that the time intervals’ range is within a few minutes so as to guarantee the accuracy. We also point out potential threats towards outsourced time-sensitive files and present security analyses to prove that Chronos $^{{\mathbf +}}$ + is secure against these threats. Comprehensive performance evaluations demonstrate the efficiency and practicality of Chronos $^{{\mathbf +}}$ + .

Coalescences in continuous-state branching processes

Consider a continuous-state branching population constructed as a flow of nested subordinators. Inverting the subordinators and reversing time give rise to a flow of coalescing Markov processes with negative jumps, which correspond to the ancestral lineages of individuals in the current generation. The process of the ancestral lineage of a fixed individual is the Siegmund dual process of the continuous-state branching process. We study its semi-group, its long-term behaviour and its generator. In order to follow the coalescences in the ancestral lineages and to describe the backward genealogy of the population, we define non-exchangeable Markovian coalescent processes obtained by sampling individuals according to an independent Poisson point process over the flow. These coalescent processes are called consecutive coalescents, as only consecutive blocks can merge. They are characterized in law by finite measures on $\mathbb{N} $ which can be thought as the offspring distributions of some inhomogeneous immortal Galton-Watson processes forward in time.

Comprehensive study of instable regions in Pseudomonas aeruginosa and Mycobacterium tuberculosis

BackgroundPseudomonas aeruginosa is a common bacterium which is recognized for its association with hospital-acquired infections and its advanced antibiotic resistance mechanisms. Tuberculosis, one of the major causes of mortality, is initiated by the deposition of Mycobacterium tuberculosis. Accessory sequences shared by a subset of strains of a species play an important role in a species’ evolution, antibiotic resistance and infectious potential.ResultsHere, with a multiple sequence aligner, we segmented 25 P. aeruginosa genomes and 28 M. tuberculosis genomes into core blocks (include sequences shared by all the input genomes) and dispensable blocks (include sequences shared by a subset of the input genomes), respectively. For each input genome, we then constructed a scaffold consisting of its core and dispensable blocks sorted by blocks’ locations on the chromosomes. Consecutive dispensable blocks on these scaffold formed instable regions. After a comprehensive study of these instable regions, three characteristics of instable regions are summarized: instable regions were short, site specific and varied in different strains. Three DNA elements (directed repeats (DRs), transposons and integrons) were then studied to see whether these DNA elements are associated with the variation of instable regions. A pipeline was developed to search for DR pairs on the flank of every instable sequence. 27 DR pairs in P. aeruginosa strains and 6 pairs in M. tuberculosis strains were found to exist in the instable regions. On the average, 14% and 12% of instable regions in P. aeruginosa strains covered transposase genes and integrase genes, respectively. In M. tuberculosis strains, an average of 43% and 8% of instable regions contain transposase genes and integrase genes, respectively.ConclusionsInstable regions were short, site specific and varied in different strains for both P. aeruginosa and M. tuberculosis. Our experimental results showed that DRs, transposons and integrons may be associated with variation of instable regions.

SUSTAINABLE INNOVATIVE DEVELOPMENT AND ITS INVESTMENT SUPPORT AS FACTORS OF RAISING THE AGROINDUSTRIAL COMPLEX EFFICIENCY

Raising of economic efficiency and sustainability of the national agroindustrial production in conditions of fast development of science, machinery and technology, high market competition, and integration processes expansion is largely conditioned by development activation, implementation and investment support of innovations. Enough attention is paid to the issues of sustainability, innovative development and investment activity in modern economic literature. At the same time, the problem of investment support for sustainable innovative development of agroindustrial complex is still studied poorly, which makes scientific research in this field relevant. Based on brief retrospective analysis, an improved understanding of the sustainable development of the agroindustrial complex, as well as in the context of its components, is proposed in the paper. It is shown that the basis for sustainable agroindustrial complex development in modern conditions is the increase of innovative activity at all the management levels. As a result of the study, a list of the main regulatory and legal acts regulating the issues of innovation activity and the privileges and incentives established by them for business entities, including agrarian ones, were systematized. The main problems preventing activation of innovative development of agroindustrial production are listed. In order to solve these problems the authors within the research framework developed a concept of investment support for sustainable innovative development of the agrarian sector, which includes eight interrelated consecutive blocks. Implementation of the proposed concept will contribute to more complete involvement of potential financing sources and their effective use in the investment activities, thereby ensuring competitiveness of the national agroindustrial complex and its sustainable development, considering interests of the current and future generations.

Influence of the Sequence in Conjugated Triblock Copolymers on Their Aggregation Behavior

Conjugated diblock copolymers can exhibit very promising properties, often based on microphase separation. However, both blocks can influence each other’s aggregation behavior, which might lead to a suboptimal aggregation behavior of the consecutive blocks. Herein, we investigate whether the introduction of a third, nonaggregating block can render triblock copolymers where the two blocks do not influence the aggregation behavior of one another. Different triblock copolymers consisting of solely thiophene units as well as triblock copolymers containing selenophene and (a)chiral thiophene units were designed to investigate the influence of the sequence of the blocks, the initiating unit, and the nonaggregating block on the aggregation behavior of the resulting triblock copolymers. The conjugated triblock copolymers were synthesized via a controlled Kumada catalyst transfer condensative polymerization (KCTCP), and their aggregation behavior was investigated via UV–vis and circular dichroism (CD) spectroscopy. For all synthesized polymers it was observed that when two aggregating blocks are separated from each other by a nonaggregating block, they do not influence each other’s aggregation behavior and aggregate separately. However, when the two aggregating blocks are situated next to each other, they influence each other’s aggregation behavior strongly and aggregate as one block.