Finite-region stability of 2-D singular Roesser systems with directional delays

In this paper, the problem of finite-region stability is studied for a class of two-dimensional (2-D) singular systems described by using the Roesser model with directional delays. Based on the regularity, we first decompose the underlying singular 2-D systems into fast and slow subsystems corresponding to dynamic and algebraic parts. Then, with the Lyapunov-like 2-D functional method, we construct a weighted 2-D functional candidate and utilize zero-type free matrix equations to derive delay-dependent stability conditions in terms of linear matrix inequalities (LMIs). More specifically, the derived conditions ensure that all state trajectories of the system do not exceed a prescribed threshold over a pre-specified finite region of time for any initial state sequences when energy-norms of dynamic parts do not exceed given bounds

Research on microstructure and mechanical properties of Al-Zn-Mg-Cu alloy when modified by La, Ce and thermo-mechanical treatment

Influence of rare-earth (La, Ce) and thermo-mechanical treatment on microstructure and mechanical properties of Al-Zn-Mg-Cu alloy are presented in this article. After casting, the alloy which was modified by La, Ce, the grain size of samples obtained around 40–50 µm compared to that of without about 65 µm; and after homogeneous, the grain sizes is about 30 µm. After the cold deformation process, the distance between plates is 10 µm. By EDS after casting, the samples have tended to more La, Ce elements at the grain boundary, after homogeneous, the uniformation distribution of rare-earths was presented by mapping of EDS’s results. In addition, after rolling and heat treatment, the elements were found on the grain boundary and matrix. After recrystallization annealing, the grain size is around 10 µm with the modification sample. The grain size was reduced by two processes of modification as well as thermal-mechanical treatment is a condition for increasing the ductility of the studied alloy. Further, as a result of ability deformation from the tensile test, these results demonstrate that the tensile test obtained 140 % when adding La, Ce contents into the alloy combine with thermal-mechanical treatment. The combined used of La, Ce and thermal-mechanical treatment have increased the ductility of Al-Zn-Mg-Cu allo

A Status Data Transmitting System for Vessel Monitoring

This paper presents a status data transmitting system suitable for vessel monitoring. The system consists of four main parts, which are a status data module, a frequency synthesizer, a power amplifier and a horn antenna. The status data module packs information of the identification, longitude, latitude and state of the vessel into data frames. FSK/MSK/GMSK schemes were used to modulate the data. The frequency synthesizer was designed with very high stability over temperature and very low frequency tolerance. The power amplifier provides 130 W output power at S band. The impedance bandwidth of the horn antenna can be controlled using the beveling technique

Efficient Detectors based on Group Detection for Massive MIMO systems

In Multiple Input Multiple Output (MIMO) systems, the complexities of detectors depend on the size of the channel matrix. In Massive MIMO systems, detection complexity becomes remarkably higher because the dimensions of the channel matrix get much larger. In order to recover the signals in the up-link of a Massive MIMO system at reduced complexities, we first divide the system into two sub-systems. After that, we apply the Minimum Mean Square Error (MMSE) and Bell Laboratory Layer Space Time (BLAST) detectors to each subsystem, resulting in the so-called MMSE-GD and BLAST-GD detectors, respectively. To further enhance the BER performance of Massive MIMO systems under the high-load conditions, we propose two additional detectors, called MMSE-IGD and BLAST-IGD by respectively applying the conventional MMSE and BLAST on the sub-systems in an iterative manner. It is shown via computer simulation and analytical results that the proposed detectors enable the system to achieve not only higher BER performance but also low detection complexities as compared to the conventional linear detectors. Moreover, the MMSE-IGD and BLAST-IGD can significantly improve BER performance of Massive MIMO systems

Anatomical Characteristics and Variants of Prostatic Artery in Patients of Benign Hyperplasia Prostate by Digital Subtraction Angiography

AIM: This work is aimed to describe anatomical features and variants of the prostatic artery (PA) using digital subtraction angiography (DSA). METHODS: This is a descriptive statistic study. We reviewed the DSA of 348 patients, who had a PA embolisation to reduce the benign prostatic hyperplasia (BPH) symptoms at Radiology Department of Bach Mai Hospital from Oct – 2014 to Oct – 2018. RESULTS: PA was found at 660 pelvic halves, of which 30 pelvic halves (4.5%) had two PAs, 630 pelvic halves had one PA. In terms of the origin of PA, in total 690 PAs, the percentage of type 1, 2, 3, 4 and 5 was successively 33.9%, 13.9%, 18.3%, 23.9% and 10.4%, respectively. Atherosclerosis of PA observed in 20.9%. The ‘corkscrew’ pattern was found in 30.4%. The average diameter of PA was 1.5 ± 0.34mm. The anastomosis of PA with surrounding arteries was common. PA may supply rectum (6.1%), seminal vesical (9.6%), bladder (5.2%), contralateral prostatic parenchyma (13.0%), surrounding soft-tissues (3.5%). CONCLUSION: The common trunk with SVA superior vesical artery was the most common origin of PA. Anastomoses of PA with surrounding tissues were complex

Geographic isolation created distinct pelage characters in Finlayson’s squirrel on isolated island offshore of the Indochina Peninsula in Central Vietnam

We found distinct pelage characters in Finlayson’s squirrel (Callosciurus finlaysonii) population, which is endemic to Lao Island of the Cham Islands, located off the coast of central Vietnam. Among squirrels of the ‘C. erythraeus-finlaysonii complex’, which consists of all forms of C. erythraeus and C. finlaysonii, mitochondrial cytochrome-b sequences show that the Lao Island squirrel forms a cluster with C. finlaysonii with external characters of C. erythraeus flavimanus, defined previously as ‘C. finlaysonii morpha flavimanus’. Both squirrel forms, however, differed in pelage colour. This different colouration may have arisen from the effect of geographic isolation

A Comparative Study of Optical Bistability in Three-Level EIT Configurations

We present a comparative study of optical bistability (OB) in three-level atomic configurations, including $\Lambda$-, cascade-, and V- types under the conditions of electromagnetically induced transparency (EIT). In the steady regime, the input-output intensity relations for the OB in each configuration have been derived in analytical form. The model allows one to construct a clear picture on how the threshold intensity, and other characteristics of the OB are continuously modified with respects to controllable parameters of the laser fields, cooperation parameter, and other physical parameters of atomic system. The results showed that the threshold intensity of OB in $\Lambda$-type system is much less than the other ones and the threshold intensity of OB in V-type system is the largest one. The analytical result is convenient to choose excitation configuration for experimental observations and related applications in photonic devices