Error Exponents for Variable-length Block Codes with Feedback and Cost Constraints

Variable-length block-coding schemes are investigated for discrete memoryless channels with ideal feedback under cost constraints. Upper and lower bounds are found for the minimum achievable probability of decoding error $P_{e,\min}$ as a function of constraints R, \AV, and $\bar \tau$ on the transmission rate, average cost, and average block length respectively. For given $R$ and \AV, the lower and upper bounds to the exponent $-(\ln P_{e,\min})/\bar \tau$ are asymptotically equal as $\bar \tau \to \infty$. The resulting reliability function, $\lim_{\bar \tau\to \infty} (-\ln P_{e,\min})/\bar \tau$, as a function of $R$ and \AV, is concave in the pair (R, \AV) and generalizes the linear reliability function of Burnashev to include cost constraints. The results are generalized to a class of discrete-time memoryless channels with arbitrary alphabets, including additive Gaussian noise channels with amplitude and power constraints

Aeroacoustics of the swinging corrugated tube: Voice of the Dragon

When one swings a short corrugated pipe segment around one’s head, it produces a musically interesting whistling sound. As a musical toy it is called a “Hummer” and as a musical instrument, the “Voice of the Dragon.” The fluid dynamics aspects of the instrument are addressed, corresponding to the sound generation mechanism. Velocity profile measurements reveal that the turbulent velocity profile developed in a corrugated pipe differs notably from the one of a smooth pipe. This velocity profile appears to have a crucial effect both on the non-dimensional whistling frequency (Strouhal number) and on the amplitude of the pressure fluctuations. Using a numerical model based on incompressible flow simulations and vortex sound theory, excellent predictions of the whistling Strouhal numbers are achieved. The model does not provide an accurate prediction of the amplitude. In the second part of the paper the sound radiation from a Hummer is discussed. The acoustic measurements obtained in a semi-anechoic chamber are compared with a theoretical radiation model. Globally the instrument behaves as a rotating (Leslie) horn. The effects of Doppler shift, wall reflections, bending of the tube, non-constant rotational speed on the observed frequency, and amplitude are discusse

Whistling of corrugated pipes

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Sea level: measuring the bounding surfaces of the ocean

The practical need to understand sea level along the coasts, such as for safe navigation given the spatially variable tides, has resulted in tide gauge observations having the distinction of being some of the longest instrumental ocean records. Archives of these records, along with geological constraints, have allowed us to identify the century-scale rise in global sea level. Additional data sources, particularly satellite altimetry missions, have helped us to better identify the rates and causes of sea level rise and the mechanisms leading to spatial variability in the observed rates. Analysis of all of the data reveals the need for long-term and stable observation systems to assess accurately the regional changes as well as to improve our ability to estimate future changes in sea level. While information from many scientific disciplines is needed to understand sea level change, this paper focuses on contributions from geodesy and the role of the ocean’s bounding surfaces: the sea surface and the Earth’s crust

Aeroacoustics of corrugated pipes

In thin walled pipes corrugations provide local stiffness while allowing global flexibility. This unique characteristic makes corrugated pipes convenient for applications ranging from domestic appliances to natural gas transportation. At critical conditions, however, the flow through these pipes drives self-sustained flow oscillations that lead to high-amplitude sound generation, called whistling. While the literature provides crucial information on the whistling of corrugated pipes, there has been no attempt until now to develop a quantitative prediction method for the whistling of corrugated tubes. The main objective of the thesis is to develop a physical understanding of aeroacoustic sound generation due to self sustained flow oscillations in ducted cavities and to provide a quantitative prediction method for the whistling in corrugated pipes. The presented work combines experimental, numerical and analytical approaches to achieve this goal. Experiments have been performed not only for corrugated pipes but also for multiple side branch systems and axisymmetric cavities in a pipe. These different setups are designed to address different aspects of the whistling in corrugated pipes. During experiments the emphasis has been on an accurate determination of the acoustic and hydrodynamic boundary conditions, which is essential for the numerical method. The extensive set of experimental data provides information on the effect of a number of geometrical parameters on the whistling namely, the length of the pipe, the cavity depth, the cavity width, the cavity edge radius and the separation distance between the cavities. Experiments also provide an understanding of the nature of the acoustic sources and the effect of velocity profile on the whistling. In corrugated pipes the cavities are small compared to the wave length of the acoustic waves, which allows the use of a simplified approach. A numerical method that combines 2D-axisymmetric incompressible flow simulations with Vortex-Sound Theory is proposed to determine the time averaged acoustic source power produced by single or multiple axisymmetric cavities. The proposed numerical method is a computationally efficient approach. Thus, it was possible to use it extensively to address most of the aspects that have been investigated experimentally. Once equipped with realistic acoustic and hydrodynamic boundary conditions, the numerical method appears to be very successful in predicting many aspects of the whistling including: Strouhal number ranges of acoustic energy production and absorption, the Strouhal number of maximum acoustic energy production (peakwhistling Strouhal number), the nonlinear saturation mechanism responsible for the stabilization of the limit cycle oscillation, the effect of the velocity profile on the whistling, the hydrodynamic interference observed between successive cavities. Using an energy balance whistling amplitude can be predicted within a factor two for moderate-high pulsation amplitude range. The sound radiation from a short corrugated pipe segment (Hummer), used as a musical instrument, has been investigated. An analytical radiation model is proposed for the prediction of the observed frequency and the sound pressure level at the listener position. The radiation model also qualitatively explains the amplitude modulation, which provides the chorus like sound quality of this instrument

Aeroacoustics of corrugated pipes

In thin walled pipes corrugations provide local stiffness while allowing global flexibility. This unique characteristic makes corrugated pipes convenient for applications ranging from domestic appliances to natural gas transportation. At critical conditions, however, the flow through these pipes drives self-sustained flow oscillations that lead to high-amplitude sound generation, called whistling. While the literature provides crucial information on the whistling of corrugated pipes, there has been no attempt until now to develop a quantitative prediction method for the whistling of corrugated tubes. The main objective of the thesis is to develop a physical understanding of aeroacoustic sound generation due to self sustained flow oscillations in ducted cavities and to provide a quantitative prediction method for the whistling in corrugated pipes. The presented work combines experimental, numerical and analytical approaches to achieve this goal. Experiments have been performed not only for corrugated pipes but also for multiple side branch systems and axisymmetric cavities in a pipe. These different setups are designed to address different aspects of the whistling in corrugated pipes. During experiments the emphasis has been on an accurate determination of the acoustic and hydrodynamic boundary conditions, which is essential for the numerical method. The extensive set of experimental data provides information on the effect of a number of geometrical parameters on the whistling namely, the length of the pipe, the cavity depth, the cavity width, the cavity edge radius and the separation distance between the cavities. Experiments also provide an understanding of the nature of the acoustic sources and the effect of velocity profile on the whistling. In corrugated pipes the cavities are small compared to the wave length of the acoustic waves, which allows the use of a simplified approach. A numerical method that combines 2D-axisymmetric incompressible flow simulations with Vortex-Sound Theory is proposed to determine the time averaged acoustic source power produced by single or multiple axisymmetric cavities. The proposed numerical method is a computationally efficient approach. Thus, it was possible to use it extensively to address most of the aspects that have been investigated experimentally. Once equipped with realistic acoustic and hydrodynamic boundary conditions, the numerical method appears to be very successful in predicting many aspects of the whistling including: Strouhal number ranges of acoustic energy production and absorption, the Strouhal number of maximum acoustic energy production (peakwhistling Strouhal number), the nonlinear saturation mechanism responsible for the stabilization of the limit cycle oscillation, the effect of the velocity profile on the whistling, the hydrodynamic interference observed between successive cavities. Using an energy balance whistling amplitude can be predicted within a factor two for moderate-high pulsation amplitude range. The sound radiation from a short corrugated pipe segment (Hummer), used as a musical instrument, has been investigated. An analytical radiation model is proposed for the prediction of the observed frequency and the sound pressure level at the listener position. The radiation model also qualitatively explains the amplitude modulation, which provides the chorus like sound quality of this instrument

Vehicle Routing Problem in Pharmaceuticals Distribution and Genetic Algorithm Application

2018 International Conference on Artificial Intelligence and Data Processing, IDAP 2018 --28 September 2018 through 30 September 2018 -- --Since vehicle routing problem was first expressed in mathematical terms in late 1950s, it has found ways of application for many daily problems in different disciplines (waste collection, product transportation from warehouses to supermarkets, school buses etc.) as well as being one of the most academically researched subjects. Apart from small scale problems, vehicle routing problem becomes np-hard combinatorial optimization problem especially when trying to solve real daily life problems. Therefore, although heuristic algorithms do not guarantee optimum results, they are used quite often in vehicle routing problems.In this study, the routing problem of a main pharmaceuticals warehouse for delivering orders to 200 pharmacies operating in three different cities and their districts is solved using genetic algorithm, one of the most effective and most used heuristic algorithms. The model devised in the study determines distribution route from the main warehouse to pharmacies with minimum cost by minimizing total travel distance and number of vehicles and using vehicle capacities in the most effective way possible. In the end, two optimum solutions with regards to various aspects such as total distance and number of vehicles are presented with their cost values. © 2018 IEEE

Aeroacoustics of the swinging corrugated tube : voice of the dragon

When one swings a short corrugated pipe segment around one’s head, it produces a musically interesting whistling sound. As a musical toy it is called a "Hummer" and as a musical instrument, the "Voice of the Dragon." The fluid dynamics aspects of the instrument are addressed, corresponding to the sound generation mechanism. Velocity profile measurements reveal that the turbulent velocity profile developed in a corrugated pipe differs notably from the one of a smooth pipe. This velocity profile appears to have a crucial effect both on the non-dimensional whistling frequency (Strouhal number) and on the amplitude of the pressure fluctuations. Using a numerical model based on incompressible flow simulations and vortex sound theory, excellent predictions of the whistling Strouhal numbers are achieved. The model does not provide an accurate prediction of the amplitude. In the second part of the paper the sound radiation from a Hummer is discussed. The acoustic measurements obtained in a semi-anechoic chamber are compared with a theoretical radiation model. Globally the instrument behaves as a rotating (Leslie) horn. The effects of Doppler shift, wall reflections, bending of the tube, non-constant rotational speed on the observed frequency, and amplitude are discussed

A novel silver recovery method from waste photographic films with NaOH stripping

WOS: 000181586900017A novel, simple, fast, cheap and pollution-free method was developed for recovering the silver from waste X-ray photographic films with NaOH stripping. The method has a number of advantages because it obviates the need for burning, oxidizing, electrolysis or purifying steps. Moreover, all experiments were carried out in the same flask, unlike other techniques. Silver recovery conditions were optimized and silver a purity level of 99% was recovered. The metal impurities (Al, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb and Sn) in the recovered silver were determined using the ICP-MS method. The results were compared with results in the literature for high-purity silver using the same method