Design and Implementation of Priority Queuing Mechanism on FPGA using Concurrent Periodic EFSMs and Parametric Model Checking

In this paper, we propose a design and implementation method for priority queuing mechanisms on FPGAs. First, we describe behavior of WFQ (weighted fair queuing) with several parameters in a model called concurrent periodic EFSMs. Then, we derive a parameter condition for the concurrent EFSMs to execute their transitions without deadlocks in the specified time period repeatedly under the specified temporal constraints, using parametric model checking technique. From the derived parameter condition, we can decide adequate parameter values satisfying the condition, considering total costs of components. Based on the proposed method, high-reliable and high-performance WFQ circuits for gigabit networks can be synthesized on FPGAs

Design and Implementation of FPGA Circuits for High Speed Network Monitors

Due to the recent progress of the Internet, we need high-speed network monitors which can observe millions of packets per second. Since several types of network attacks occur, we need to modify monitoring facilities and their capacities depending on monitoring items and network speed. In this paper, we propose (1) a methodology for designing and implementing such network monitors flexibly and (2) a high-level synthesis technique which automatically synthesizes FPGA circuits from specifications of network monitors in a model called concurrent synchronous EFSMs. The proposed technique makes it possible to synthesize an FPGA circuit suitable for given monitoring items and parameters where the designer need not consider about how pipe-line processing and parallel processing should be adopted. We have developed a tool to automatically derive FPGA circuits and evaluated the speed and size of derived circuits

No significant difference found in PET/MRI CBF values reconstructed with CT-atlas-based and ZTE MR attenuation correction

Abstract Background Accurate attenuation correction (AC) is one of the most important issues to be addressed in quantitative brain PET/MRI imaging. Atlas-based MRI AC (AB-MRAC), one of the representative MRAC methods, has been used to estimate the skull attenuation in brain scans. The zero echo time (ZTE) pulse sequence is also expected to provide a better MRAC estimation in brain PET scans. The difference in quantitative measurements of cerebral blood flow (CBF) using H2 15O-PET/MRI was compared between the two MRAC methods, AB and ZTE. Method Twelve patients with cerebrovascular disease (4 males, 43.2 ± 11.7 years) underwent H2 15O-PET/MRI studies with a 3-min PET scan and MRI scans including the ZTE sequence. Eleven of them were also studied under the conditions of baseline and 10 min after acetazolamide administration, and 2 of them were followed up after several months interval. A total of 25 PET images were reconstructed as dynamic data using 2 sets of reconstruction parameters to obtain the image-derived input function (IDIF), the time-activity curves of the major cerebral artery extracted from images, and CBF images. The CBF images from AB- and ZTE-MRAC were then compared for global and regional differences. Results The mean differences of IDIF curves at each point obtained from AB- and ZTE-MRAC dynamic data were less than 5%, and the differences in time-activity curves were very small. The means of CBF from AB- and ZTE-MRAC reconstructions calculated using each IDIF showed differences of less than 5% for all cortical regions. CBF images from AB-MRAC tended to show greater values in the parietal region and smaller values in the skull base region. Conclusion The CBF images from AB- and ZTE-MRAC reconstruction showed no significant differences in regional values, although the parietal region tended to show greater values in AB-MRAC reconstruction. Quantitative values in the skull base region were very close, and almost the same IDIFs were obtained

A Flexible and High-Reliable HW/SW Co-Design Method for Real-Time Embedded Systems

In this paper, we propose a flexible and high-reliable HW/SW co-design method for real-time systems consisting of multiple functional modules using general purpose components such as DSP, CPU and memory. In our method, we specify a system as a parallel composition of concurrent periodic EFSMs with timing constraints. As communication primitives among EFSMs, multi-way synchronization mechanism can be specified. Here, we propose a technique for efficient development of real-time embedded systems considering both reliability and cost-performance. For the purpose, using a parametric model checking technique, we derive a parameter condition which must hold for the system to proceed without deadlocks and satisfy given timing constraints. Based on the derived parameter condition and cost-performance characteristic of available components, an appropriate combination of components is automatically selected so that the total cost is minimized. We have developed a design support tool based on the proposed technique. By applying our method to development of a basic functionality of a cellular phone, we could decide which functional modules should be implemented as dedicated HW units or on-chip-CPUs' software, and select suitable DSPs and memories with low costs

Assessment of Arterial Transit Time and Cerebrovascular Reactivity in Moyamoya Disease by Simultaneous PET/MRI

We investigated the relationship between MRI-arterial spin labeling (ASL) parameters and PET-cerebral blood flow (CBF)/cerebrovascular reactivity (CVR) simultaneously obtained by PET/MRI in Moyamoya disease. Twelve patients underwent 15O-water PET/MRI with the acetazolamide (ACZ) challenge test. PET-CBF and PET-CVR were measured using 15O-water PET. Pseudo-continuous ASL obtained the robust arterial transit time (ATT) and ASL-CBF estimation. ASL parameters were compared with PET-CBF and PET-CVR. Before ACZ loading, absolute and relative ASL-CBF were significantly correlated with absolute and relative PET-CBF (r = 0.44, p p p p p p p 30% (898 ± 197 ms). ASL-ATT ratio of MCA territories with CVR 30% (81.4 ± 11.3%). ATT correction using multiple postlabeling delays increased the accuracy of ASL-CBF quantitation. Baseline ASL-ATT is a hemodynamic parameter and may represent an efficient alternative to PET-CVR

Effect of newly developed scissors-attached micro-forceps on the recipient clamp time and occurrence of anastomotic site infarction after bypass surgery for moyamoya disease

IntroductionThis study aimed to examine the effect of newly developed scissors-attached micro-forceps in superficial temporal artery-to-middle cerebral artery (STA-MCA) anastomosis for moyamoya disease (MMD).Materials and methodsOf 179 consecutive STA-MCA anastomoses on 95 hemispheres of 71 MMD patients at the University of Fukui Hospital between 2009 and 2023, 49 anastomoses on 26 hemispheres of 21 patients were enrolled in this retrospective cohort clinical trial intraoperative indocyanine green video-angiography did not demonstrate bypass patency in three anastomoses in two patients who were excluded. Twenty-one anastomosis in 19 hemispheres of 16 patients were performed using the conventional micro-forceps (conventional group, CG), and 25 anastomoses in 22 hemispheres of 19 patients were performed using scissors-attached micro-forceps (scissors group, SG). A small infarction near the anastomotic site detected using postoperative diffusion-weighted imaging was defined as anastomotic site infarction (ASI). Factors affecting the occurrence of ASI were examined by univariate, logistic regression, and receiver operating curve (ROC) analysis.ResultsThere were no significant differences in clinical parameters such as age, sex, number of sacrificed branches, number of sacrificed large branches, and number of sutures between the CG and SG. However, the clamp time and occurrence of ASI were significantly lower in the SG than in the CG. Logistic regression analysis revealed that the clamp time was the only significant factor predicting the occurrence of ASI. A receiver operating curve analysis also revealed that the clamp time significantly predicted the occurrence of ASI (area under the curve, 0.875; cutoff value, 33.2 min).ConclusionThe newly developed scissors-attached micro-forceps could significantly reduce the clamp time and occurrence of ASI in STA-MCA anastomosis for MMD