Dynamic Joint Scheduling of Anycast Transmission and Modulation in Hybrid Unicast-Multicast SWIPT-Based IoT Sensor Networks

The separate receiver architecture with a time- or power-splitting mode, widely used for simultaneous wireless information and power transfer (SWIPT), has a major drawback: Energy-intensive local oscillators and mixers need to be installed in the information decoding (ID) component to downconvert radio frequency (RF) signals to baseband signals, resulting in high energy consumption. As a solution to this challenge, an integrated receiver (IR) architecture has been proposed, and, in turn, various SWIPT modulation schemes compatible with the IR architecture have been developed. However, to the best of our knowledge, no research has been conducted on modulation scheduling in SWIPT-based IoT sensor networks while taking into account the IR architecture. Accordingly, in this paper, we address this research gap by studying the problem of joint scheduling for unicast/multicast, IoT sensor, and modulation (UMSM) in a time-slotted SWIPT-based IoT sensor network system. To this end, we leverage mathematical modeling and optimization techniques, such as the Lagrangian duality and stochastic optimization theory, to develop an UMSM scheduling algorithm that maximizes the weighted sum of average unicast service throughput and harvested energy of IoT sensors, while ensuring the minimum average throughput of both multicast and unicast, as well as the minimum average harvested energy of IoT sensors. Finally, we demonstrate through extensive simulations that our UMSM scheduling algorithm achieves superior energy harvesting (EH) and throughput performance while ensuring the satisfaction of specified constraints well.Comment: 29 pages, 13 figures (eps

Behavior of Connections Between SHS Columns & W-section Beams

Connections between SHS (Square Hollow Section) columns and W-section beams are generally fabricated by welding with or without endplates in the factory. These welded connections possess some finite degree of rotational stiffness which falls between fully rigid and ideally pinned joints. The influence of partially restrained connections on structural response not only changes the moment distribution but also increases frame drift. In this paper, a series of connection tests joining SHS column and W-section beam were executed and the test results compared with theoretical values. A method to utilize nonlinear moment-rotation relations of beam-to-column connections in steel framed structures is proposed. For the problem of contact in endplate-type connections, a simple and efficient method is also introduced

The effect of low temperature aging on the mechanical property & phase stability of Y-TZP ceramics

STATEMENT OF PROBLEM. Recently Yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP) has been introduced due to superior flexural strength and fracture toughness compared to other dental ceramic systems. Although zirconia has outstanding mechanical properties, the phenomenon of decrease in the life-time of zirconia resulted from degradation in flexural strength after low temperature aging has been reported. PURPOSE. The objective of this study was to investigate degradation of flexural strength of Y-TZP ceramics after various low temperature aging treatments and to evaluate the phase stability and micro-structural change after aging by using X-ray diffraction analysis and a scanning electron microscope (SEM). MATERIAL AND METHODS. Y-TZP blocks of Vita In-Ceram YZ (Vita Zahnfabrik, Bad Sa ¨ckingen, Germany) were prepared in 40 mm (length) x 4 mm (width) x 3 mm (height) samples. Specimens were artificially aged in distilled water by heattreatment at a temperature of 75, 100, 125, 150, 175, 200, and 225℃ for 10 hours, in order to induce the phase transformation at the surface. To measure the mechanical property, the specimens were subjected to a four-point bending test using a universal testing machine (Instron model 3365; Instron, Canton, Mass, USA). In addition, X-ray diffraction analysis (DMAX 2500; Rigaku, Tokyo, Japan) and SEM (Hitachi s4700; Jeol Ltd, Tokyo, Japan) were performed to estimate the phase transformation. The statistical analysis was done using SAS 9.1.3 (SAS institute, USA). The flexural strength data of the experimental groups were analyzed by one-way analysis of variance and to detect statistically significant differences (α= .05). RESULTS. The mean flexural strength of sintered Vita In-Ceram YZ without autoclaving was 798 MPa. When applied aging temperature at below 125℃ for 10 hours, the flexural strength of Vita In-Ceram YZ increased up to 1,161 MPa. However, at above 150℃, the flexural strength started to decrease. Although low temperature aging caused the tetragonal-to-monoclinic phase transformation related to temperature, the minimum flexural strength was above 700 MPa. CONCLUSION. The monoclinic phase started to appear after aging treatment above 100℃. With the higher aging temperature, the fraction of monoclinic phase increased. The ratio of monoclinic/tetragonal + monoclinic phase reached a plateau value, circa 75% above 175℃. The point of monoclinic concentration at which the flexural strength begins to decrease was between 12% and 54%.This work was supported by the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government(MOST) (No. R01-2007-000-10977-0)

Light-chain amyloidosis presenting with rapidly progressive submucosal hemorrhage of the stomach

SummaryThe gastrointestinal tract is frequently in involved light-chain (AL) amyloidosis, but significant hemorrhagic complications are rare. A 71-year-old man presented to our hospital with dyspepsia and heartburn for 1 month. Gastroscopy revealed a large submucosal hematoma at the gastric fundus. Two days later, a follow-up gastroscopy indicated extensive expansion of the hematoma throughout the upper half of the stomach. The hematoma displayed ongoing expansion during the endoscopic examination, suggesting that rupture was imminent. Emergency total gastrectomy was performed, and amyloidosis was confirmed after examining the surgical specimen. Bone marrow examination revealed multiple myeloma, and serum immunoglobulin assay confirmed the diagnosis of myeloma-associated AL amyloidosis. At manuscript submission, the patient was doing well and was undergoing chemotherapy