A Guide to Buying an Mp3 Multimedia Player

Portable music and video today and the future. What the trends are.

With digital music coming, the mp3 player has taken the high ground in digital music and video entertainment. So, what exactly are we talking about? MP3 is a term that relates to a standard of digital audio processing that allows digital audio files to be compressed in size and therefore made more portable. The mp3 player today however, is much more than simply a device that plays only mp3 standard audio files. It is now a universal term that includes players of all forms of portable audio formats and is used to identify a wide range of hardware from an equally wide range of player manufacturers, and a plethora of websites offering downloadable media. Clearly it is not so much whether you will listen to digital music and watch digital video, but the type of player that will best suit your purposes.

What is your passion? How you want to consume your media?

There are a number of important issues to consider when choosing the type of player that will suit your requirements best. At the heart of this is the question of how you want to consume your music and video product. With the digital music revolution come three basic options. You can choose a player that has a hard disc for program storage, one that uses flash memory (memory sticks, flash cards and the like) or one that uses standard CD format with music stored in mp3 or other compressed formats. There is no one universal method that will suit everybody. Rather there are pros and cons for each, with different manufacturers offering different features, design, battery life, useability and prices.

The other really important development that may affect how you choose the right player is the fact that the online music and video programming is now widely available from all manner of sources, from artist direct through to iTunes. As the protection of artist’s and producer’s digital rights becomes more widespread, you can expect media players to be more able to share the different media formats and protection. reducing risk both for you and the artists involved.

The Hard-Drive Option.

The crucial decision is how much memory. Hard-Drive players, such as Apple’s iPod, are available with up to 100GB of storage (but this could change in any nano-second). While they are physically small, Hard-Drive players are not the lightest. But 60 GB allows about a thousand hours of mp3 music. At around 4 minutes per song, that’s about 15,000 songs. If being able to store a lot of songs is important to you, then you should consider the Hard-Drive option. Of course video program is more memory consumptive, and if you need to store large video programs then a Hard-Drive option makes good sense. A Hard-Drive player has a small computer hard-drive installed inside, so it has moving parts and can be damaged by shock, severe magnetic fields and too much sun. Some can also be quite bulky which means that a hard-drive player may not ideally suit a jogger, but if you fly Sydney to London on a regular basis, then it could be the solution. Hard-Drive players also tend to have a shorter battery discharge life than flash memory devices.

The Flash Memory Option.

Flash memory offers some outstanding benefits. At the time of writing, flash memory goes up to 4GB, which allows about one thousand mp3 songs. When you consider the average radio station’s active play list is less than two hundred songs at any given time, and shrinking, a 1,000-song capacity is quite substantial. In current recording terms, that could be as many as 60 to 100 albums. Moreover, flash memory has no moving parts and so can withstand slightly rougher treatment. And players can be considerably smaller and therefore more portable. Additional benefits come in the form of small, yet quite powerful storage media and astounding battery life.

The CD Media Option.

Following on from the Sony Walkman phenomenon, portable CD players have been around for some years. Now however, portable CD players can play mp3 and other compressed audio formats as well as standard CDs. Using this technology, you can download your music to your computer and burn it onto a CD in mp3 format, and play it in your portable player. You don’t need to concern yourself with storage capacity. A single CD will hold 700 MB of music, or around 175 songs. These players are limited in their other functions, but are often cheap to buy. However because they use CD technology (and therefore have moving parts), they are susceptible to shock and it can be quite inconvenient to carry a whole bunch of CDs around if you need a large library of music on your jogging circuit.

Controlling what you hear.

Okay, so we’ve sorted out how you want to consume your music and now you have some leaning as to which type of player is going to suit you based on its media system and storage capacity. But there is still more for you to consider. There are two aspects to being able to control your audio through your mp3 player. One is its connectivity. In the first instance, you need to be able to download the music you want to hear in the format that’s going to suit your player, and vice versa. So first you need to make sure you choose a player that is compatible with the source. (Frankly, you can’t go far wrong with iTunes and most players, but there are many other options, including Virgin, Napster, Sony, all of which offer different media options.) Second, you need to have a simple connection between the computer you download your program onto and your portable mp3 player. Most players these days use USB serial interfaces. But there are also fire wire and wireless options. You also may want to consider whether you want to receive FM radio on your mp3 player, and whether you want to use your mp3 player to record program (much like a cassette player).

These features are available on some players, but not on all. Furthermore, the recording options may be limited. A player that can record only wave files will limit your recording capacity. (One minute of stereo wave file is about 10 megabytes, compare with one megabyte in mp3 format.) There has long been the promise of music kiosks where you can simply charge a flash memory stick with new songs. Perhaps we will see this in the coming year.

The second aspect to controlling what you hear is the audio environment itself. You connect your mp3 player to your physical self through earphones, or you can plug it into your computer, your hi-fi system, and even use a wireless connection in your car. Not surprisingly however, one of the weakest links in the personal portable mp3 player is the earphone set. Most players come with a set of earphones, usually in the ‘bud’ style. Not everyone is comfortable with this style of earphone, and you may want to consider the earphones you use. A good quality set of earphones, (such as Shure’s E4c) will enhance your listening experience for a variety of reasons. For prolonged listening, earphones need to be comfortable, both in a physical sense and in an auditory sense. Poor quality earphones are often uncomfortable to wear and deliver poor quality sound that can cause ear fatigue and subsequent long-term damage. Cheap earphones are flimsily constructed and any strong tug on the cords will cause the signal cables to break down. You also need to check out what controls the player provides you over the sound quality, and how easily they are accessed and understood. At minimum, you need volume and possibly some tonal controls, as well as track management and good visible indicators of the status of your player.

Size does matter.

The importance of weight, physical dimensions and battery life cannot be understated. Most manufacturers promote a battery life. But like mobile phones, the product usually does not prove the claim. Why is this? It often depends on how the battery life is measured. In a laboratory for example, the test may be carried out with minimal human interference. But on the jogging path, every time you touch a control, you are using some power from the battery, whether it’s just to illuminate the screen, or make adjustments to the sound quality. Battery life can be compared between manufacturers to give you some idea of how different players compare, but don’t rely on the manufacturer’s claims to be accurate under the conditions you will be using your player. You may use your player for a few hours each day, and then recharge every night. In such a case, extremely long battery discharge life may not be too important. But if you are trekking across the Nullarbor Plain and won’t see a power point for several days, battery life is going to be critical.

Weight is also another factor. Remember, devices with Hard-Drive storage weigh more and are bulkier than devices with flash memory. CD devices need to be at least as big as a CD, and many are not much bigger. Consider how you are going to wear the player on your person, and be sure it will be comfortable.

And there are accessories

There are a lot of technical things associated with audio devices. Unless you’re an audiophile, you may have a limited interest in such things as the signal to noise ratio (the amount of noise that is generated outside of the signal by the players amplifiers). The fact is, most players on the market have acceptable sound fidelity and the biggest weakness can often be found in the headsets and loudspeaker systems that they are connected to. You may also want to consider the accessories that are available, either included with the purchase or available separately. This may include power adaptors, carrying cases, additional memory, car adaptors and other software options to give you access to a wider range of entertainment and information.

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Documenting Visual Quality Controls on the Evaluation of Petroleum Reservoir-Rocks Through Ontology

1 Introduction:

The most important intrinsic properties of petroleum reservoir rocks are their porosity – the percentage of their total volume occupied by fluids, i.e., oil, natural gas or water – and their permeability – the amount of such fluids that can flow through a rock section in a time unit. The values and distribution of porosity and permeability within reservoir rocks are conditioned by depositional and post-depositional (diagenetic) aspects, such as the depositional structures, grain size and selection, the types, textures and location of diagenetic processes and constituents. These parameters are described during the systematic petrographic analysis of reservoir rocks, in order to provide the essential information for the creation of models for the characterization of the quality and heterogeneity of reservoirs under production, or for the prediction of quality of new reservoirs during exploration. Therefore, the acquisition and documentation of the key textural and compositional petrographic features has an enormous importance for the evaluation of effective or potential reservoir rocks. However, capturing information from images is a natural uncertain process. Image recognition involves previous knowledge and hypothesis about what is being seen, the progressive adjustment of the viewer in order to fit the understanding to the seen features during image scanning and, also, judgments about the significance of this features related to geological interpretation.

This paper describes an approach to overcome the difficulty in applying visual knowledge in reservoir evaluation. We formalize a workflow for the systematic description and storage of the key visual petrographic features, as seen in petrographic microscopes, and provide computer support by a system composed by a piece of software and hardware. The treatment of uncertainty provided by the system was conceived to deal with the incomplete collection of information and the partial confidence of the expert interpretation rules. The system tries to offer the best support to overcome the information loose in image recognition. It provides a petrographic ontology to orient the feature recognition and, when it is done, saves the spatial locations of the key features and associates them both to ontological terms as well as to hyperlinks for other objects supporting the description, such as pictures, audio and video files, websites, etc. As a result, it produces a complete documentation of the features, in the form of a virtual map of the thin section, that preserves the evidences for the reservoir evaluation. The reasoning method searches over this description for the required features to prove one or other interpretation hypotheses.

The approach was implemented in the PetroGrapher system, an intelligent database application designed to support the detailed petrographic description and interpretation of oil reservoir rocks, and the management of relevant data using resources from both relational databases and knowledge-based expert systems. Systematic description through the system is facilitated by the use of flexible menus with standardized nomenclature and parameters, what radically reduces description time and errors. An integrated electromechanical microscope stage, the StageLedge, allows an optimized quantification, as well as the referencing of every point identified and/or photographed in the thin sections. The collection of qualitative features is driven by a domain ontology [1] that formalize the knowledge related to petrographic description and diagenetic interpretation. The main approaches of PetroGrapher system are described in [2-4]. In this paper, we present the basis for the automation of the process of quantitative petrographic analysis with the support of an electromechanical appliance [5] attached to the microscope and interfaced to the software system. This approach reduces the uncertainty associated to visual interpretation by improving the semantic capturing and allowing a better register for recovering the evidences that support inference. This information is used by the problem-so living method implemented in the system to propose the probable diagenetic environment where the rock where formed. The petrographic analysis is accomplished through two stages. First, the petrographer analyzes the fabric, texture and structure of the rock, and identifies the main rock-forming constituents, pores and diagenetic relations. After that, he/she performs a quantitative analysis, through the systematic scanning of the rock, following a virtual grid of evenly-spaced points over the thin section. During this scanning, the petrographer identifies and annotates the constituents and the diagnostic features that may suggest interpretations of reservoir quality. In addition, important features may be captured through photographs, which can be annotated later on.

Although the qualitative and quantitative description is a systematic process, it is strongly affected by different styles of descriptions and subjective factors. Petrographers with distinct levels of expertise can produce quite different descriptions, mainly because the spatial relationships among the constituents, or paragenetic relations, as well as uncommon minerals are not properly recorded. Even the same petrographer when recalling a previous description may find it difficult to check some of its specific aspects, because the original position and described points over the thin section cannot be found again with precision. Our approach helps in minimizing the information loose typical of the visual-based interpretation process by providing a standard description based on a complete formal vocabulary and petrographic support tables. It also supports the capture of all features along with the original spatial position in the rock, and allows the re-utilization of information, even in the absence of the original object.

2 Preliminary Concepts

The structuring and the representation of the knowledge for problem solving in domains that require image pattern matching and then high level of abstract inference is a challenge for knowledge engineering although is essential for many critical tasks, such as automatic surveillance in intensive care units [6], recognition of biological organisms [7], and biochemistry [8]. The uncertainty in the task are related mainly to the follow factors: (1) the collection of information is not complete because the observer does not posses the knowledge to recognize what is being seen providing incomplete or wrong descriptions; (2) even with the adequate capture of the diagnostic features, the level of significance of these features in indicating a particular interpretation may not provide a fully trustful solution. Our system helps in making available the knowledge by supporting the feature recognition through a domain ontology and providing a problem-solving method to deal with significance and confidence factors of the interpretation task.

2.1 Ontology and Image Annotation

Ontologies that formalize the visual concepts of the domain are shown as the alternative to reduce the gap between the knowledge representation and image features, as presented in [9] and also in this paper. The most common definition of ontology asserts that an ontology is a formal, explicit specification of a shared conceptualization [10]. Formal refers to the fact that the ontology should be machinereadable, and shared reflects the notion that an ontology captures consensual knowledge, accepted by a group. Ontologies express the descriptive knowledge and also the way in which the evidences support the conclusions. Usually, they are combined with problem-solving methods [11] to provide reasoning features to expert systems, like we done in our system. There are many approaches to ontology-based content annotation of images, based on a standardized vocabulary defined by a domain ontology that allows further processing [11] [6] [12]. Images must be annotated with keywords and content-based combined queries and refinements [13]. During annotation, a lot of information can be expressed, helping to improve the understanding and to reduce ambiguity. The images can also be annotated with links over the image to any kind of multimedia content like it was done in [14]. It is possible to associate data under analysis to different resources, in order to provide a complete documentation.

2.2 Spatial Referencing

A spatial reference system provides an association of the object with its location related to a specific coordinate system. A coordinate system can reference a particular point in an n-dimensional space defined by an origin, directions of the axis and a distance scale. The quantitative analysis of a thin section in an optical microscope is usually done referring each identified feature to an imaginary net of points along a sequence of evenly-distanced steps, corresponding to successive positions marked by the cross lines of the microscope eyepiece. In some cases, this net is scanned with the help of some equipment, such as performed in [5] and in [15]. However, the complete association of the net of points to a spatial coordinate system with an anchor linked to a real reference of a physical object, as developed in this work, is a new proposition.

3 Petrographic Analysis Using Software Control and the StageLedge Device

In order to support the systematic quantitative analysis in the PetroGrapher system, we have developed an electromechanical device, called StageLedge [5], to be attached to the optical microscope and connected to a software control. The quantification of the constituent elements requires a uniform scanning of the thin section, so we have defined an automatic method. This approach not only guarantees that the thin section can be completely explored, but most important, that the entire process can be repeated, preserving the spatial coordinates of each point of the virtual map.

3.1 Virtual Thin Section

Our approach is based on the creation of a digital version of the thin section, on top of which virtual feature maps can be created. Although it does not completely eliminate the need for the real thin section, it has some significant advantages over the traditional approach that uses the original section both for description and for later verifications. This virtual thin section allows the recording of reference features through an existent ontology. For instance, our electronic version of the section can be sent over the Internet to an arbitrary number of petrographers, who can independently go over the reasoning process previously applied in the original documentation. Besides reducing the risks associated with a possible loss of the physical section, it also eliminates the costs associated to shipping the real thin section. Moreover, the virtual thin section has the potential for unlimited documentation via hyperlinks to images, video, audio, and text provided by expert petrographers, as well as to other resources available on the Internet and related to the contents of the section. This sets the stage for a new level of rich documentation, turning the virtual thin sections into ideal training tools. This situation would show an image corresponding to a portion of a thin section containing links to different media formats: audio, video, other images, websites, and other observations.
These resources intent to complement the information that is captured by the user, minimizing the lack of comprehension about what is seen in the description time. The images should have less than two megabytes to not slow down the system execution.

3.2 Complete Description Process

The analysis of a thin section starts with its positioning in the petrographic microscope, which has a rotating stage that allows the examination of the optical properties of minerals when examined with polarized light. The direction of the transect lines across which the points are quantified during analysis is defined transversally to the structures and fabric of the rock, and the modal size of grains indicates the adequate size of the step to be used with the StageLedge.

In the process of creating a digital map of the rock, we digitize a physical thin section using a regular flatbed scanner and use the resulting image as a base map on top of which the additional documental information will be placed. This stage requires the careful correction of the scale, tilt and coordinates of origin of the scanned image, in order to provide a correct association with the origin and scale provided by StageLedge. Once the image has been captured and associated to the actual position in the equipment, the documentation can be referenced to the real spatial coordinates. Since flatbed scanners can capture images at different resolutions, it is necessary to specify the selected resolution in points per inch (ppi), thus relating pixels to real distances in the thin section. According to our experience, the use of 600 ppi provides satisfactory results. In order to support the petrographic description, the PetroGrapher system controls the steps of the StageLedge and allows the user to select constituents and features described in the domain ontology and associates them to the current position under analysis in the thin section.

The quantitative petrographic analysis identifies and saves the location of every constituent positioned in each of the coordinates in the virtual net, controlled by StageLedge. The PetroGrapher interface depicts different minerals using colors. Thus, with just a quick glance, the geologist can have a good idea of the spatial distribution of the constituents and pores identified in the thin section.

The possible constituents and pores that can be found in a thin section are fully described in a domain ontology, as well as the attributes and domain of values of them. The ontology also describes in which way the instances of qualified constituents can indicates the rock-formation environment. This is expressed by knowledge graphs, a one-level tree where the root node represents the interpretation hypothesis and the leaf nodes represent visual chunks identified by the experts in the image of rock as pieces of evidence necessary to support the interpretation. The uncertainty of interpretation is represented in the knowledge-graph by a threshold value that represents the minimum amount of evidence needed to indicate it. Also, the chunks have an influence factor and are combined to increase the influence and the certainty of the interpretation stated. By their side, the chunks represents in an AND-OR tree the several ways in which way an evidence can be recognized in the rock, such as, possible minerals, possible habits, locations, etc. The knowledge model and problem-solving method of the system is extensively described in [3]. For each significant feature identified in the thin section, the user can capture a photograph and associate it to the coordinates of the described point or annotate the captured image itself, describing the special characteristics that must be considered. Thus, the quantitative analytical process generates a map containing the documentation of the most important diagnostic features for reservoir evaluation. According to the user interest, the system can selectively show the location of the special features, as exemplified in the left window, where the segments indicate the trajectory of the analysis and the white dots shows the position of the selected constituent. As the user moves the mouse over a point for which a picture has been taken, it is automatically shown in right side window. This documentation will provide further validation to the reasoning process or may show possible errors in feature identification.

The digital map of the rock uses the digital thin section image as a base map on top of which the additional documental information will be placed. This stage requires the careful correction of the scale, tilt and coordinates of origin of the scanned image, in order to provide a correct association with the origin and scale provided by StageLedge. Once the image has been captured and associated to the actual position in the equipment, the documentation can be referenced to the real spatial coordinates. At the end of the process, an extensive documentation of the thin section is provided. For example, it is possible to locate where the 10th detrital quartz is located and then visualizing it. Moreover, the system guarantees that all descriptions would be performed based on a formal and complete petrographic vocabulary, defined in the domain ontology. This feature will provide extra capabilities by allowing the automatic geological interpretation and correlation with the captured information.

3.3 The interpretation process

The features described are stored in a database, along with the spatial coordinates of their position in the virtual map. The reasoning method loads each knowledge graph and match the chunk representation from the knowledge base against the user descriptions on the database. When the set of features that describes a chunk is found, the reasoning accumulates the related influence factor. When the sum reach the threshold of the graph, the conclusion is stored in the database in the description record and presented to the user. More than a conclusion can be associated to one rock, since more than one environment can act in rock consolidation.

4 Conclusions

The tool described in this paper has been tested by a group of six geologists from the Geosciences Institute at the Federal University of Rio Grande do Sul (Brazil), who works usually with petrographic analysis. The group has long time experience with the manual method and has migrated recently to PetroGrapher system. The goal was measuring the time expending in the task description and the amount of information that was collected in each method in normal work condition. Each participant received six different rock samples to be described. Each sample was described by four geologists, two using the PetroGrapher system, two using an electronic spreadsheet and a mechanical stage. According to these experiments, the use of the PetroGrapher system with the StageLedge has led to a reduction of 25% in the time required for a full petrographic description. Otherwise, the descriptions are longer and contain more information than those made by manual method. The spontaneous comments from PetroGrapher´s users include: (1) the system guarantees a standard documentation without losing semantic of feature description; (2) the possibility of recovering the original position of some specific feature provides a better framework for reservoir understanding; and (3) the information can be easily queried and reused. As a result, one can draw further correlations between petrographic data and well logs, seismic profiles and core descriptions. These capabilities are essential for a powerful tool used for advanced reservoir characterization.

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