Metodo de medicion de combustible en una embarcacion fluvial.

Se expone una forma de mejorar el método de medición de combustible en una embarcación fluvial, específicamente en un remolcador. El marco de referencia sobre el que se basa este artículo, es la estrategia utilizada para establecer la cantidad de combustible presente en los tanques de la embarcación. El método que hasta el momento se viene utilizando, produce un error influenciado por factores de perturbación, como la inclinación y la forma de tanqueo del remolcador. Se buscó desarrollar un método alternativo que redujera el error entre el combustible entregado y el medido en la embarcación. Este nuevo método logró ser independiente de la inclinación sin necesidad de utilizar un inclinómetro o instrumento de medida de ángulos.
Palabras claves: medición de niveles, centroide, punto de sondeo, sensores de presión.
Abstract
This paper exposes a way to improve the method of fuel measurement in a river vessel, specifically a tugboat. The framework of this article is the need of a strategy to establish the amount of fuel volume that is contained in the tanks of the tugboat. The method, that have been used so far, produces errors influenced by disturbance factors such as the inclination and the shape of the tanks of the tugboat. It is needed to develop an alternative method that reduces the error between the fuel which is provided by the suppliers and the measured one in the tugboat. This new method tries to be independent of the inclination of the boat with no need of using a clinometer or instrument of angle measurement.
Key words: level measurement, centroid, test point, pressure sensors.
1 Introducción
El marco de trabajo en el cual surge este método de medida de combustible es el desarrollo de un proyecto en la modalidad universidad--empresa. El proyecto denominado "Sistema de Telemetría para Remolcadores", involucra una empresa del sector carbonero de la región caribe colombiana y la Universidad del Norte como centro de desarrollo tecnológico, y comprende: la construcción de un sistema de adquisición de señales, el desarrollo de un sistema de posicionamiento de la embarcación y la creación de un sistema de gestión de operaciones del remolcador.
La necesidad más importante que la empresa desea suplir con el desarrollo del proyecto, es el monitoreo continuo de la cantidad de galones de combustible en los tanques de los remolcadores, que permita tomar decisiones desde el punto de vista logístico, que apunten a la reducción del rubro correspondiente a gastos operacionales del estado de pérdidas y ganancias. Este proyecto, concebido para el desarrollo de un prototipo, involucra un remolcador con seis tanques de combustible repartidos uniformemente, es decir, tres a cada lado de la embarcación. Si bien los tanques son iguales con respecto a su contraparte del otro lado, los tanques de un flanco del remolcador son diferentes entre sí y no son prismas rectangulares rectos. Adicionalmente, debido a que el medio en el cual el remolcador se encuentra trabajando permite modificaciones en el plano horizontal del marco de referencia de la embarcación, el método de medición del nivel de combustible que se seguía hasta el inicio del proyecto, incluía errores que afectaban la operación logística de la empresa. De esta forma, se desarrolla un método experimental de medición, lo más independiente posible, de inclinaciones proa-popa y estribor-babor.
En la sección (2) se presentan la configuración de los tanques del remolcador que funcionó como prototipo, sus formas, método de medida empleado hasta entonces y los problemas que involucraba.
Posteriormente, en la sección (3), se presentan los conceptos matemáticos que permitieron la búsqueda y desarrollo de un método alternativo, así como la elección de una estrategia de sensado conveniente para el caso particular.
En la sección (4) se presenta un resumen del desarrollo de la estrategia con base en lo expuesto en la sección (3). Finalmente, en la sección (5) se muestran los resultados y conclusiones.
(2) Antecedentes: tanques y sus propiedades, método de medida anterior
El remolcador utilizado para el desarrollo del sistema prototipo, cuenta con dos motores de propulsión, dos generadores eléctricos y seis tanques de almacenamiento de combustible, denominados bodegas. Las bodegas se encuentran repartidas de forma tal que las tres de un flanco sirven al motor y/o generador del lado correspondiente. Las bodegas se denominan, de proa a popa: bodega 1, bodega 2 y bodega 3, adjuntando a la clasificación la palabra estribor o babor, dependiendo de la ubicación del tanque, tal y como se muestra en la figura (1).

Blind deconvolution of the aortic pressure waveform using the Malliavin calculus

1. Introduction

In this paper, we present a new approach to monitor central arterial pressure using the Multichannel Blind Deconvolution (MBD)[1, 2]. A multichannel blind deconvolution problem can be considered as natural extension or generalization of instantaneous Blind Source Separation (BSS) problem [3, 4]. The problem of BSS has received wide attention in various fields such as signal analysis and processing of speech, image [5, 6], and biomedical signals, especially, signal extraction, enhancement, denoising, model reduction, and classification problems [7-9].

The MBD is the technique that allows the estimation of both an unknown input and unknown channel dynamics from only channel outputs. Although one cannot place a sensor [10] to directly measure the input, yet, it may be recovered from the outputs that are simultaneously measured at the multiple branches of the system. The MBD technique distinguishes itself from other techniques that apply a predetermined transfer function [11, 12] to interpret sensor data. The other techniques cannot account for individual differences nor can they account for dynamic changes in the subject's physiologic state.

The physiologic state of the cardiovascular (CV) system can be most accurately assessed by using the aortic blood pressure or CAP [7, 13, 14] and flow. However, standard measurement of these signals, such as catheter, entails costly and risky surgical procedures. Therefore, most of the practically applicable methods aim to monitor the CV system based on peripheral circulatory signals, for example, arterial blood pressure at a distant site. Various methods have been developed to relate the peripheral signals to the CV state. These include blind deconvolution [15-17] methods for recovering the CAP signal from the upper-limb arterial blood pressure, and the estimation of CV parameters such as left ventricular elasticity, end diastolic volume, total peripheral resistance (TPR), and mean aortic flow from arterial BP measurement [18, 19]. A chronic challenge of these previous methods is that the dynamics of the CV system, which relates the aortic and peripheral signals, is unknown and time-varying as well. So this problem turns out to be an ill-posed system identification problem because we are asked to identify both the unknown system dynamics and input signal using the output signal measurement alone.

Because of the practical difficulty in measuring the arterial pressure waveform near the heart [13, 15, 20], several mathematical transformation methods have been developed based on a generalized transfer function approach [21, 22]. Over the years many methods have been suggested for blind deconvolution for estimating central aortic pressure and flow [3, 9, 19, 23, 24]. One of the most popular and effective techniques is to assume an FIR model [1] and IIR model [18, 19, 25] for the modulating channels/paths and to estimate the coefficients [26] of this model. Through the inversion of the FIR filter, we get the original source signals. The principal assumption underlying these methods is that the arterial tree properties are constant over time and between individuals. A few methods have therefore been more recently developed towards "individualizing" the transfer function [1, 12, 21 ] relating peripheral artery pressure to central aortic pressure. These methods essentially involve (1) modeling the transfer function [11, 23] with physiologic parameters, (2) estimating a subset of the model parameters [7,15] from the peripheral arterial pressure waveforms and/or other measurements from an individual while assuming values for the remaining parameters, (3) constructing a transfer function based on the estimated and assumed parameter values [26], and(4) applying the transfer function to the measured peripheral arterial pressure waveforms to predict the corresponding central aortic pressure waveform. While these methods attempt to determine a transfer function that is specific to an individual over a particular time period, only a partial individualization is actually obtained. Perhaps, as a result, these methods have found only limited success with results not much, if at all, better than the generalized transfer function approach.

In this paper, we suggest characterizing the channels of the single-input, multi-output system model of the arterial tree by linear and time-variant FIR filters. If we make only one of the FIR filter parameters changing over time, then the problem is handled by the Ito calculus [27,28], while, if we make more than one of the FIR filter parameters changing over time, then the problem could be handled by the Malliavin calculus [29] as we propose in this paper.

This way, the ambiguity in the order of the impulse response is compensated by the time variations of the filter parameters [29-31].

In this paper, we introduce a method that could estimate time-varying parameters/coefficients. It is based on the stochastic calculus of variations (Malliavin calculus) 28, 32-35]. We derive a closed-form expression for the unknown time varying FIR filter parameters by using the Clark-Ocone formula [30]. This will enable us to find a stochastic differential equation (SDE) for each unknown time-varying parameter of the FIR filter. Each SDE is function of PAP and some other unknown deterministic parameters. The unknown deterministic parameters are estimated through Monte Carlo simulation methods.

The proposed method is then applied to noninvasive monitoring of the cardiovascular system of the swine. The arterial network is modeled as a multichannel system where the CAP is the input and pressure profiles measured at different branches of the artery, for example, radial and femoral arteries, are the outputs. The proposed method would allow us to estimate both the waveform of the input pressure and the arterial channel dynamics from outputs obtained with noninvasive sensors placed at different branches of the arterial network. Numerical examples verify the major theoretical results and the feasibility of the method. In Section 2, we describe the blind deconvolution problem, conventional solution methods. In Section 3 we introduce the proposed method based on the Malliavin calculus. In Section 4, we present the results for the reconstruction of single-input CAP from two distant measures outputs PAP. Finally in Section 5, we provide summary and conclusions. The Appendix contains the technical derivations of the proposed method.

2. Problem Formulation

2.1. Multichannel Dynamic Systems

The cardiovascular system is topologically analogous to a multichannel dynamic system. Pressure wave emanating from a common source, the heart, is broadcast and transmitted through the many vascular pathways. Therefore, noninvasive circulatory measurements taken at different locations (as shown in Figure 3) can be treated as multichannel data and processed with an MBD algorithm. Figure 1 illustrates, in a block diagram form, the relation between the central aortic pressure waveform u(t) and the peripheral arterial pressure waveforms [y.sub.i] (t). The arterial channels [h.sub.i](t) relating the common input to each output represent the vascular dynamic properties of different arterial tree paths as characterized by finite impulse responses (FIRs). The main idea is therefore to determine the absolute central aortic pressure waveform within an arbitrary scale factor by mathematically analyzing two or more PAP waveforms or related signals so as to extract their common features. An ancillary idea is to then determine the parameters of the determined central aortic pressure waveform.

We estimate the FIR filter coefficients by the conventional methods in Section 2.2. We introduce our proposed method that is based on Malliavin calculus in Section 3. We will be working in the probability space ([OMEGA], F, P). To simplify the exposure, we shall assume that we have only two measurements outputs of a modulated version of the source signal that are given as

[y.sub.1](t) = [h.sub.1] (t) * tu() + [[epsilon].sub.1](t), (2.1)

[y.sub.2](t) = [h.sub.2] (t) * tu() + [[epsilon].sub.2](t), (2.2)

[FIGURE 1 OMITTED]

where u(t) is the unknown source signal (central AP), [h.sub.1](t) and [h.sub.2](t) are unknown filters (hemodynamic response at time t) or arterial paths, "*" is the convolution operation, [y.sub.1](t) (femoral AP) and [y.sub.2](t)(radial AP) are the observed measurements, and [[epsilon].sub.1](t) and [[epsilon].sub.2](t) are the measurements noise. The objective is to deconvolve [y.sub.1](t) and

Make Mobile Phone Batteries Last Longer

There is certainly nothing more irksome than having the cell phone die out when you are midway in an important conversation. Almost all users of mobile phones have had this experience. The tiny battery indicator appears to be on full charge but then suddenly drops off the display without any forewarning. We do find that some cell phone batteries last much longer than others. The only possible reason for this must be how you care for and maintain your battery. We have to learn from those whose battery live longer their secret technique.
It is quite likely that all batteries are as different as the phones they come with. But there should not be seriously different when it comes to the power they supply. It is reported that an average life expectancy a well-maintained cell phone battery can be range between 350-400 full charge cycles. In other words, if you find it necessary to re-charge your mobile daily, then you should expect to get anything from 12 to 14 months of effective use. After this time you should reasonably expect to see the battery deteriorate and lose its power faster over time. Much depends how frequently you use your mobile. If you use your mobile less often and therefore only need to recharge it every 2 or 3 days, then you could see the life or your battery last even beyond two years.
The assured way to get the most out of your cell phone battery is to adhere strictly to the manufacturers charging instructions. If you disregard the instructions, then you can only have a shorter life expectancy of your battery. Besides, the battery will also lose charge much quicker. So remember to scrupulously follow the initial charging instructions as they are contained in the user manual. Usually the manufacturers recommend you to allow the battery to completely lose all of its charge before the first recharge.
Sharp changes in temperature can also reduce the life-span of your cell phone battery. Little realizing this fact, most people leave phone in the car during extreme weather conditions - both hot as well as cold weather. Yet another mistake most cell phone users commit is to leave their phone plugged into the car's charger at all times. What these people need to know is that every time the engine is restarted, the phone starts a charge cycle unnecessarily thus wasting a charge cycle. Please bear in mind that cell phone batteries only have a fixed number of charge cycles before they begin to wither away. But it should also be said that your battery could deteriorate if you do not charge it often enough.
If you are an occasional user, you may let it keep losing all of its charge as often as possible. If you are planning not to use your phone or you are going to an area where there is no signal, then the right thing is to turn off the phone. This is the most effective and simplest way of prolonging battery life. You should – even more so - switch off when you are in a roaming area as constant search for a signal depletes the battery faster. Also make sure to turn off the vibrate mode and use only the ring mode. The vibrate mode consumes a lot of power and rapidly drains the battery. Even the ring volume must be kept as low as possible.

Turn off your phone’s rear light. The back light may make the phone easier to read but this light also uses battery power. If you switch off the light, your battery will surely last longer. Minimize the use of all fancy features. Avoid using the camera, internet and games. Accessing these features will result in a large drain on the battery. Bluetooth should also be turned off when not in use as it also drains your battery fast.

Advancing your Career

To survive and prosper in current competitive setting, it is not only what you know. Also, you have to be qualified. You must excel the crowd - be impressive, memorable,  credible, liked and trusted. Maya Sullivan once said that success is not a destination, but this is a journey. Follow the provided tips to better your career. 1. Surpass expectations; deliver your results on head of time. 2. You should manage your time efficaciously. 3. You need to make a career plan with training requirements and goals. 4. Also, you need to move away from daily operations. 5. It is recommended to develop strong relations with your colleagues, senior executives/managers. 6. Find a mentor and accept guidance in the career. 7. In addition, you should know the organization's goals vision, business strategies, values. 8. Create options to further business/own goals. 9. Solicit feedback plus evaluate the decision for targets of continuous improvement. 10. Effectively communicate to people at various levels of the organization. 11. Create and maintain rapport with people who might influence the work. 12. Plan, prioritize and arrange your work. 13. You should manage your own reactions and emotions. 14. Balance the requirements of your professional and personal life. 15. You need to give yourself quarterly observations, identify the accomplishments. 16. Become your sales team and market your capabilities. 17. Devote yourself to womb-to-tomb learning. 18. Be action oriented and decisive. 19. You should commit to professionalism and excellence. 20. And at last you ought to be self-disciplined

Free Laptop- How To Get Your Hands On One!

If you are a bit skeptical about the veracity of some advertisements on the internet about free laptops, you have all the reason to be and nobody is blaming you for thinking that way. But what if some people would attest that there are indeed companies who can give away free laptops, what would you do? Well it wouldn’t surprise anyone if you would log on to the internet and find a company who would prove that certain promos really exist and yes, some companies do give out free laptops in exchange for something else, of course.

Laptops are some of the few gadgets that anybody would surely love to have. Almost all people these days need laptops. Students, employees, managers, office workers and people from different walks of life would love to have one in order to make their work easier and to keep abreast with the events in the world. Nobody would be surprised to hear that more and more companies would use laptops for their promos in order to entice their customers or clients to patronize their products or their services.

In the internet you can find a lot of free laptop programs that you can find if you want a free laptop to be given to you. But there’s a catch however. You surely can’t have that laptop just like that, don’t you think so? Well, there’s no need to worry. Nobody will force you to reveal your account numbers and your pertinent information. You don’t have to deposit a certain amount of money in order to have it because if that’s the case, why waste your time and money for a silly promo? Why not buy a laptop right there on laptop stores, right? So what do you need to do? You simply have to subscribe to these free laptop programs and there you’ll have your dream laptop.

To make sure that you are not dealing with a scam, here are few tips you will have to bear in mind.

•Read the whole program. Examine all the details including the terms and the conditions.

•Ask about the hidden information. Verify everything that is written before you finally agree to the terms and conditions.

•Ask about shipping charges and subscription fee.

•Ask if you have to pay for hidden sign-up fee.

•Check on the company’s profile.

•Find out about the different sites that are tested to really give free laptops.

Finally, when you are able to do all of these things, you can have the free laptop that you are wishing for. Not everybody is lucky enough to have the chance, so grab the opportunity by browsing the internet for free laptops programs now!

One last thing to remember that there is no obligation or payment required to sign up with these free laptops offerings. All you need is your email address where you will be getting your verification email. You can use a free hosted email like Hotmail, Gmail, or Yahoo mail which makes it extremely easy to sign up with these programs

Introduction to LCD technology

If you are currently looking for a new monitor or high definition TV, you might have noticed that many are using the LCD technology. This is all fine but what exactly is LCD and how does it affect the image quality?

LCD is an acronym for Liquid Crystal Display a technology used largely on televisions, laptops and computer monitors. It is worth mentioning that LCD is not the same as Plasma although they do produce the same results in terms of image quality.

LCD uses the properties of polarized light to display images. Liquid crystal solution that is divided into individual pixels is inserted between two transparent polarized panels and sandwiched together to form a LCD screen. In the early days the LCD technology was mainly used on small digital products like watches, calculators and portable video game devices. Over the years the technology has been improved considerably and consequently imported to other devices like laptops. It took some time before LCD monitors and TVs became widely available because the earlier models had many drawbacks namely the lack of image quality. This tendency was inverted with the introduction of affordable LCD TVs and monitors.

The new generation of LCD monitors have been improved especially in terms of energy consumption and the much needed image quality. Nowadays the main advantages presented by LCD technology are centered in the fact that it allows the screen to be much thinner than the traditional cathode ray tube (CRT) and consumes less power because they work by blocking light rather than emitting it. The life expectancy of a LCD screen, although it can vary considerably among the different brands, lasts on average for up to 60,000 viewing hours. In the end the LCD technology provides a significantly superior image than the old CRT monitors and TVs.

Research Commentary: Desperately Seeking the "IT" in IT Research—A Call to Theorizing the IT Artifact

The field of information systems is premised on the centrality of information technology in everyday socio-economic life. Yet, drawing on a review of the full set of articles published in Information Systems Research (ISR) over the past ten years, we argue that the field has not deeply engaged its core subject matter—the information technology (IT) artifact. Instead, we find that IS researchers tend to give central theoretical significance to the context (within which some usually unspecified technology is seen to operate), the discrete processing capabilities of the artifact (as separable from its context or use), or the dependent variable (that which is posited to be affected or changed as technology is developed, implemented, and used). The IT artifact itself tends to disappear from view, be taken for granted, or is presumed to be unproblematic once it is built and installed. After discussing the implications of our findings, we propose a research direction for the IS field that begins to take technology as seriously as its effects, context, and capabilities. In particular, we propose that IS researchers begin to theorize specifically about IT artifacts, and then incorporate these theories explicitly into their studies. We believe that such a research direction is critical if IS research is to make a significant contribution to the understanding of a world increasingly suffused with ubiquitous, interdependent, and emergent information technologies