FIFTY YEARS OF MICROPROCESSOR EVOLUTION: FROM SINGLE CPU TO MULTICORE AND MANYCORE SYSTEMS

Nowadays microprocessors are among the most complex electronic systems that man has ever designed. One small silicon chip can contain the complete processor, large memory and logic needed to connect it to the input-output devices. The performance of today's processors implemented on a single chip surpasses the performance of a room-sized supercomputer from just 50 years ago, which cost over $ 10 million [1]. Even the embedded processors found in everyday devices such as mobile phones are far more powerful than computer developers once imagined. The main components of a modern microprocessor are a number of general-purpose cores, a graphics processing unit, a shared cache, memory and input-output interface and a network on a chip to interconnect all these components [2]. The speed of the microprocessor is determined by its clock frequency and cannot exceed a certain limit. Namely, as the frequency increases, the power dissipation increases too, and consequently the amount of heating becomes critical. So, silicon manufacturers decided to design new processor architecture, called multicore processors [3]. With aim to increase performance and efficiency these multiple cores execute multiple instructions simultaneously. In this way, the amount of parallel computing or parallelism is increased [4]. In spite of mentioned advantages, numerous challenges must be addressed carefully when more cores and parallelism are used.This paper presents a review of microprocessor microarchitectures, discussing their generations over the past 50 years. Then, it describes the currently used implementations of the microarchitecture of modern microprocessors, pointing out the specifics of parallel computing in heterogeneous microprocessor systems. To use efficiently the possibility of multi-core technology, software applications must be multithreaded. The program execution must be distributed among the multi-core processors so they can operate simultaneously. To use multi-threading, it is imperative for programmer to understand the basic principles of parallel computing and parallel hardware. Finally, the paper provides details how to implement hardware parallelism in multicore systems

A novel framework for fluid/structure interaction in rapid subjectspecific simulations of blood flow in coronary artery bifurcations

Background/Aim. Practical difficulties, particularly long model development time, have limited the types and applicability of computational fluid dynamics simulations in numerical modeling of blood flow in serial manner. In these simulations, the most revealing flow parameters are the endothelial shear stress distribution and oscillatory shear index. The aim of this study was analyze their role in the diagnosis of the occurrence and prognosis of plaque development in coronary artery bifurcations. Methods. We developed a novel modeling technique for rapid cardiovascular hemodynamic simulations taking into account interactions between fluid domain (blood) and solid domain (artery wall). Two numerical models that represent the observed subdomains of an arbitrary patient-specific coronary artery bifurcation were created using multi-slice computed tomography (MSCT) coronagraphy and ultrasound measurements of blood velocity. Coronary flow using an in-house finite element solver PAK-FS was solved. Results. Overall behavior of coronary artery bifurcation during one cardiac cycle is described by: velocity, pressure, endothelial shear stress, oscillatory shear index, stress in arterial wall and nodal displacements. The places where (a) endothelial shear stress is less than 1.5, and (b) oscillatory shear index is very small (close or equal to 0) are prone to plaque genesis. Conclusion. Finite element simulation of fluid-structure interaction was used to investigate patient-specific flow dynamics and wall mechanics at coronary artery bifurcations. Simulation model revealed that lateral walls of the main branch and lateral walls distal to the carina are exposed to low endothelial shear stress which is a predilection site for development of atherosclerosis. This conclusion is confirmed by the low values of oscillatory shear index in those places

WIRELESS SENSOR NODE WITH LOW-POWER SENSING

Wireless sensor network consists of a large number of simply sensor nodes that collect information from the external environment by sensors, process the information, and communicate with other neighboring nodes in the network. Usually sensor nodes operate with exhaustible batteries unattended. Since manual replacement or recharging the batteries is not an easy, desirable and always possible task, the power consumption becomes a very important issue in the development of these networks. The total power consumption of a node is a result of all steps of operation: sensing, data processing and radio transmission. In this work we focus on the impact of sensing hardware on the total power consumption of a sensor node. Firstly, we describe the structure of sensor node architecture, identify its key energy consumption sources, and introduce an energy model for the sensing subsystem as building block of a node. Secondly, with aim to reduce energy consumption of a node we propose implementation of two power-saving techniques: duty-cycling and power-gating. Duty-cycling is effective at system level. It is used for switching a node between active and sleep mode (with duty-cycle factor of 1% reduction of in dynamic energy consumption is achieved). Power-gating is implemented at circuit level with goal to decrease a power loss due to leakage current (in our design, a reduction of dynamic and static energy consumption of off-chip sensor elements as constituents of sensing hardware within a node of is achieved). Our MATLAB simulation results suggest that in total for a sensing hardware thanks to involving of duty-cycling and power-gating secures a three order of magnitude reduction ( ) in energy consumption can be achieved compared to a node architecture in which the implementation of  both energy saving techniques are omitted

DESIGN OF COMPLEMENTARY RECURSIVE DIGITAL FILTERS BASED ON GROUP DELAY APPROXIMATION

This paper describes a new procedure for design of complementary IIR digital filters based on group delay approximation. The filters are realized as parallel sum of two all-pass filters, a structure for which low complexity implementations exist. Problem with phase warping which is inevitable if filter design is made through phase approximation will be removed using proposed method. Adequate initial solution is also proposed. Realized amplitude characteristics of complementary filters will be approximately equriripple. The design examples illustrate that the proposed algorithm is very efficient in term of computation time and number of iterations

Hemoptysis as an Early Symptom of Abdominal Actinomycosis with Thoracic Extension Ten Years after Cholecystectomy with Retained Gallstone

Abstract Background: Thoracoabdominal actinomycosis is rare, especially in the context of readily available medical facilities. Methods: Case report and review of the literature. Case Report: A 54-year-old male patient was admitted because of hemoptysis and a pulmonary infiltrate in the left lower lobe. His history was unremarkable except for chronic gastritis and an elective laparoscopic cholecystectomy performed 10 years earlier. Following persistent hemoptysis, elevated inflammatory markers, and a non-revealing bronchoscopy, a computed tomography scan of the thorax and upper abdomen revealed a tumor in the upper part of the left kidney spreading directly to the adjacent diaphragm and left lower lobe. Laparotomy revealed a granulomatous mass containing a gallstone, as well as orange granular content. The treatment involved surgical removal of the mass, splenectomy, excision of the infiltrated part of the left hemidiaphragm, and decortication of the left lower lobe. Because of a prolonged post-operative low-grade fever and radiologically confirmed encapsulation in the lingula, the patient was given ceftriaxone. Repeat bronchoscopy revealed Actinomyces meyeri. The initial antibiotic therapy was replaced with amoxicillin-clavulanic acid, after which the patient's health improved. Conclusion: Actinomycosis is still a highly intriguing disease, as initial symptoms often mislead clinicians. It is important to consider the disease whenever we are challenged diagnostically or when risk factors are present

Intracerebral hemorrhage as a first sign of pheochromocytoma: case report and review of the literature

Pheochromocytomas and sympathetic paragangliomas are rare catecholamine-secreting tumours that represent very rare causes of intracerebral haemorrhage in the young, with only a few cases reported. A 32-year-old man presented to our emergency department because of sudden onset of severe headache. He had a six-month history of paroxysmal headache, palpitations, and sweating. During examination he became somnolent and developed left-sided hemiplegia. A computed tomographic (CT) scan of the brain showed a right temporoparietal haematoma. He was admitted to the Clinic for Neurosurgery and the haematoma was evacuated. The patient was comatose, on assisted respiration, with frequent hypertensive crises. An examination for possible secondary causes of hypertension was undertaken. Plasma metanephrine value was elevated (414 pg/mL, reference values < 90 pg/mL). Abdominal CT scans revealed a large mass (6 cm) in the right adrenal gland. After adequate control of the hypertension was achieved with nonselective alpha- and beta-adrenergic blockers the tumour was excised. The histopathologic findings confirmed the diagnosis of pheochromocytoma. The genetic analysis demonstrated a duplication in exon 1 of the VHL gene. We reported a rare, potentially fatal complication of pheochromocytoma — an intracerebral haemorrhage. This case and review of similar rare cases in the literature illustrate the importance of early recognition of the characteristic symptoms of catecholamine excess in young patients with hypertension

Spectroscopic characteristics of highly selective manganese catalysis in acqueous polyurethane systems

The latest investigations on producing more efficient catalytic aqueous polyurethane systems are in the domain of metal complexes with mixed ligands. In our previous research works, the high selectivity for the isocyanate-hydroxyl reaction in aqueous polyurethane systems has been shown by the manganese(III) mixed-ligand complexes. The two new complexes have been prepared with two acetylacetonate (acac) ligands and one maleate ligand and its hydroxylamine derivative of the general formula [Mn(C5H7O2)(2)L]. Their structures have been established by using the fundamental analyses, the FTIR and UV/VIS spectroscopic methods, as well as the magnetic measurements. In order to explain the different selectivity of the manganese(III) mixed-ligand complexes, the UV and ESR spectroscopy have been employed to determine the kinetics of the complexes' decomposition. The thermal stability of the complexes has been determined by way of the dynamic TG method at the heating rate of 5 degrees C.min(-1) and at the temperature ranged 20-550 degrees C. It suggests the decomposition of the complexes by loss of acid ligand. The main factor in the selective catalysis control in the aqueous polyurethane systems is the nature of the acid ligands and their impact on the manganese(II)/manganese(III) equilibrium