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Purpose: Positron Emission Tomography (PET) has been a commonly used imaging modality in broad clinical applications. One of the most important tradeoffs in PET imaging is between image quality and radiation dose: high image quality comes with high radiation exposure. Improving image quality is desirable for all clinical applications while minimizing radiation exposure is needed to reduce risk to patients. Methods: We introduce PET Consistency Model (PET‐CM), an efficient diffusion‐based method for generating high‐quality full‐dose PET images from low‐dose PET images. It employs a two‐step process, adding Gaussian noise to full‐dose PET images in the forward diffusion, and then denoising them using a PET Shifted‐window Vision Transformer (PET‐VIT) network in the reverse diffusion. The PET‐VIT network learns a consistency function that enables direct denoising of Gaussian noise into clean full‐dose PET images. PET‐CM achieves state‐of‐the‐art image quality while requiring significantly less computation time than other methods. Evaluation with normalized mean absolute error (NMAE), peak signal‐to‐noise ratio (PSNR), multi‐scale structure similarity index (SSIM), normalized cross‐correlation (NCC), and clinical evaluation including Human Ranking Score (HRS) and Standardized Uptake Value (SUV) Error analysis shows its superiority in synthesizing full‐dose PET images from low‐dose inputs. Results: In experiments comparing eighth‐dose to full‐dose images, PET‐CM demonstrated impressive performance with NMAE of 1.278 ± 0.122%, PSNR of 33.783 ± 0.824 dB, SSIM of 0.964 ± 0.009, NCC of 0.968 ± 0.011, HRS of 4.543, and SUV Error of 0.255 ± 0.318%, with an average generation time of 62 s per patient. This is a significant improvement compared to the state‐of‐the‐art diffusion‐based model with PET‐CM reaching this result 12× faster. Similarly, in the quarter‐dose to full‐dose image experiments, PET‐CM delivered competitive outcomes, achieving an NMAE of 0.973 ± 0.066%, PSNR of 36.172 ± 0.801 dB, SSIM of 0.984 ± 0.004, NCC of 0.990 ± 0.005, HRS of 4.428, and SUV Error of 0.151 ± 0.192% using the same generation process, which underlining its high quantitative and clinical precision in both denoising scenario. Conclusions: We propose PET‐CM, the first efficient diffusion‐model‐based method, for estimating full‐dose PET images from low‐dose images. PET‐CM provides comparable quality to the state‐of‐the‐art diffusion model with higher efficiency. By utilizing this approach, it becomes possible to maintain high‐quality PET images suitable for clinical use while mitigating the risks associated with radiation. The code is availble at https://github.com/shaoyanpan/Full‐dose‐Whole‐body‐PET‐Synthesis‐from‐Low‐dose‐PET‐Using‐Consistency‐Model. [ABSTRACT FROM AUTHOR]

Mental disorders represent one of the leading social problems in the world, revolving around several theoretical models to support integrative interventions. Grawe's Consistency Model states that four basic psychological needs must be satisfied to maintain mental health. These needs refer to attachment, self-esteem, control or self-efficacy, and decreased pain and increased pleasure. Although some studies have analyzed the relationship between these constructs, few studies focused on evaluating Grawe's model. Objective. The present study aimed to evaluate the relationship between the four basic psychological needs in the Mexican population. Sixty-one participants: 29 men and 31 women, were administered a series of scales measuring the abovementioned four constructs. Results. Results showed significant correlations in the different scales and subscales. Discussion. The present study allowed a greater understanding of the basic psychological needs raised in Grawe's model in the Mexican population; however, the study had some limitations and cautionary aspects for future studies. [ABSTRACT FROM AUTHOR]

In this paper, we design and implement a distributed network virtualization hypervisor (NVH) system, namely, DPVisor, which can provide superior network programmability based on protocol-oblivious forwarding to realize highly-available, scalable, and protocol-independent virtual software-defined network slicing. The experimental comparisons indicate that DPVisor achieves comparable performance as ONVisor (i.e., an OpenFlow-based ONOS benchmark), in terms of the message processing latency, message processing throughput, and failure recovery time. Moreover, to optimize the performance of the distributed NVH systems, we carefully adjust the consistency model used in the state synchronization of NVH instances and propose a local cache-based scheme to balance the tradeoff between the consistency and availability of network status. Our experimental results confirm that the message processing throughput of the distributed NVH systems can be greatly improved (i.e., for both DPVisor and ONVisor), while the data consistency among NVH instances is still maintained well.

The CAP theorem states that only two of these properties can be simultaneously guaranteed in a distributed service: (i) consistency, (ii) availability and (iii) network partition tolerance. This theorem was stated and proved assuming that 'consistency' refers to atomic consistency. However, multiple consistency models exist and atomic consistency is located at the strongest edge of that spectrum. Many distributed services deployed in cloud platforms should be highly available and scalable. Network partitions may arise in those deployments and should be tolerated. One way of dealing with CAP constraints consists in relaxing consistency. Therefore, it is interesting to explore the set of consistency models not supported in an available and partition-tolerant service (CAP-constrained models). Other weaker consistency models could be maintained when scalable services are deployed in partitionable systems (CAP-free models). Three contributions arise: (i) multiple other CAP-constrained models are identified, (ii) a borderline between CAP-constrained and CAP-free models is set and (iii) a hierarchy of consistency models depending on their strength and convergence is built. [ABSTRACT FROM AUTHOR]

This study investigates the effect of geometric design consistency on road safety in the West Bank. Studies have shown that operating speed, vehicle stability, alignment indices, and driver's workload are the common consistency measures that might affect safety. A total of 118-km two-lane rural highways in the West Bank, Palestine, were studied based on limitations of available data. Comprehensive geometric and operating data for the selected highways obtained from field survey, maps, and official sources were used to investigate the effect of design consistency measures on road safety. Crashes for years 2008–2012, totaling 263, were used for model development using the generalized linear regression approach. Tested models were statistically significant at 95%, and adopted models showed acceptable levels of goodness of fit. The recommended model performed well across additional highway sections, additional years of data, validation of algorithm, and "%error" with a high linear correlation. The study adds to the evidence that several geometric design consistency measures contribute to roadway safety. The significant measures for the two-lane rural highways in the West Bank were segment length, traffic volume, difference between operating and design speeds, absolute difference in the 85th percentile speeds between successive design elements, and the ratio of individual curve radius to the average radius. The practical implication of this study, in addition to being able to predict crashes based on the recommended measures, highway designers should pay careful attention to inconsistent designs of two-lane rural highways to reduce their crash frequency. [ABSTRACT FROM AUTHOR]

Recent demands for storing and querying big data have revealed various shortcomings of traditional relational database systems. This, in turn, has led to the emergence of a new kind of complementary nonrelational data store, named as NoSQL. This survey mainly aims at elucidating the design decisions of NoSQL stores with regard to the four nonorthogonal design principles of distributed database systems: data model, consistency model, data partitioning, and the CAP theorem. For each principle, its available strategies and corresponding features, strengths, and drawbacks are explained. Furthermore, various implementations of each strategy are exemplified and crystallized through a collection of representative academic and industrial NoSQL technologies. Finally, we disclose some existing challenges in developing effective NoSQL stores, which need attention of the research community, application designers, and architects. [ABSTRACT FROM AUTHOR]

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Corporate governance involves not only working out the relationship between a company and its shareholders, but also a search for consistency on a daily basis. When consistency is achieved, the shareholders’ satisfaction is higher and relations improve. Consistency is a prerequisite for a company’s effectiveness and efficiency, and it is the board’s task to make a corporation consistent. The first part of the paper introduces M. Flieger’s concept of corporate consistency, where platforms of consistency are introduced and the consistency model is proposed. This is the first time that such an introduction has been made, and this may lead to further discussion and research. The author points out that managers are rarely aware of the consistency problem, and there are no tools which enable a consistent system to be worked out. This makes the concept of corporate consistency worth investigating. In the second part of the paper, R. Kaminski focuses on the development of the European Union and Polish regulations, which were introduced as a consequence of the changing conditions in company activity. This section determines the content and sequence of the main issues discussed in the article. These include: the characteristics of the concept of a corporate governance system, the presentation of changes in regulations regarding a corporate governance system in the EU and the presentation of Polish regulations on corporate governance. The primary sources used in the work were literature and the rules and standards (mandatory and optional) on corporate governance. Both authors used descriptive analysis and the comparative method.

This article investigates the handling processes versions of a record in NoSQL databases. The goal of this work is to develop a model, which enables users both to handle record versions and work with a record simultaneously. This model allows us to estimate both a time distribution for users to handle record versions and a distribution of the count of record versions. With eventual consistency (W=R=1) there is a possibility for several users to update any record simultaneously. In this case, several versions of records with the same key will be stored in database. When reading, the user obtains all versions, handles them, and saves a new version, while older versions are deleted. According to the model, the user’s time for handling the record versions consists of two parts: random handling time of each version and random deliberation time for handling a result. Record saving time and records deleting time are much less than handling time, so, they are ignored in the model. The paper offers two model variants. According to the first variant, client's handling time of one record version is calculated as the sum of random handling times of one version based on the count of record versions. This variant ignores explicitly the fact that handling time of record versions may depend on the update count, performed by the other users between the sequential updates of the record by the current client. So there is the second variant, which takes this feature into consideration. The developed models were implemented in the GPSS environment. The model experiments with different counts of clients and different ratio between one record handling time and results deliberation time were conducted. The analysis showed that despite the resemblance of model variants, a difference in change nature between average values of record versions count and handling time is significant. In the second variant dependences of the average count of record versions in database and its right bound of the confidence interval on the average deliberation time have a pronounced maximum. In the same variant an average handling time of record versions practically does not depend on the average deliberation time, but the right bound of the confidence interval of this time has a pronounced minimum.

Eventual consistency is demanded nowadays in geo-replicated services that need to be highly scalable and available. According to the CAP constraints, when network partitions may arise, a distributed service should choose between be- ing strongly consistent or being highly available. Since scalable services should be available, a relaxed consistency (while the network is partitioned) is the preferred choice. Eventual consistency is not a common data-centric consistency model, but only a state convergence condition to be added to a relaxed consistency model. There are still several aspects of eventual consistency that have not been analysed in depth in previous works: 1. which are the oldest replication proposals providing eventual consistency, 2. which replica consistency models provide the best basis for building eventually consistent services, 3. which mechanisms should be considered for implementing an eventually consistent service, and 4. which are the best com- binations of those mechanisms for achieving different concrete goals. This paper provides some notes on these important topics. [ABSTRACT FROM AUTHOR]

In this article, a rate-dependent elastoplastic-damage constitutive model considering the effect of strain rate has been developed. The derivation of this model has been established based on the irreversible thermodynamics with internal variables within the fundamentals of Continuum damage mechanics (CDM). For investigating the rate effect, an additional power function dependent on the effective strain rate has been involved in the plastic dissipation function (dynamic plastic yield surface). The damage has been assumed as a tensor-type variable and based on the energy equivalence hypothesis, the damage evolution has been developed. The proposed constitutive model has been implemented into user-defined subroutines UMAT and VUMAT in the finite-element program ABAQUS/(Standard and Explicit). For this purpose, the implicit and explicit stress integration algorithms of the model have been explained. The model has been validated by comparing the predicted results with experimental data conducted on Al2024-T3. These experiments are including the tensile and double-notched tests. Furthermore, the numerical results have been compared with some data available in the literature. The numerical examples show the excellent correlation between experiments and simulations for stress (or force) and damage results. [ABSTRACT FROM AUTHOR]

Traditional cache coherence protocols manage all memory accesses equally and ensure the strongest memory model, namely, sequential consistency. Recent cache coherence protocols based on self-invalidation advocate for the model sequential consistency for data-race-free, which enables powerful optimizations for race-free code. However, for racy code these cache coherence protocols provide sub-optimal performance compared to traditional protocols. This paper proposes SPEL++, a dual-consistency cache coherence protocol that supports two execution modes: a traditional sequential-consistent protocol and a protocol that provides weak consistency (or sequential consistency for data-race-free). SPEL++ exploits a static-dynamic hybrid classification of memory accesses based on (i) a compile-time identification of extended data-race-free code regions for OpenMP applications and (ii) a runtime classification of accesses based on the operating system's memory page management. By executing racy code under the sequential-consistent protocol and race-free code under the cache coherence protocol that provides sequential consistency for data-race-free, the end result is an efficient execution of the applications while still providing sequential consistency. Compared to a traditional protocol, we show improvements in performance from 19 to 38 percent and reductions in energy consumption from 47 to 53 percent, on average for different benchmark suites, on a 64-core chip multiprocessor. [ABSTRACT FROM AUTHOR]