A written analysis of the nature of Practitionr research Essay

A written analysis of the nature of Practitionr research - Essay Example Practitioner research has been employed as a means of bridging the gap between practice and theory. Teachers have been urged to use practitioner research, specifically action research in order to improve education and reconstruct knowledge (Berker, 1992). Other areas of practice, including health, agriculture, and the social sciences have also not been left behind in their use of practitioner research, as they are seeking to improve their knowledge base, and eventually bridging the gap between theory and practice (Fox, et.al., 2007). Various discussions on practitioner research have been forwarded, including its nature, values, and underlying activities. This paper seeks to explore the nature of practitioner research. It shall explore various issues pertaining to ethics, especially in relation to practitioner research. Firstly, it shall discuss the youth mentoring and how practitioner research applies to this field. Secondly, the importance of ethical applications in practitioner res earch will also be established. Lastly, an analysis of practitioner and action research will be carried out. Youth mentoring is a process that entails a linking of mentors with the youth, especially those that require the care of responsible adults (Rhodes and Liang, 2009). More often than not, the responsible adults (mentors) are not relatives of the mentored youths. At most, these mentors serve as volunteers under a community-based program catering to the needs of the youth population. Most definitions of the mentoring processes have revolved around the idea that an older and more experienced person would assist a much younger and less experienced individual to go through developmental stages and transition towards bigger responsibilities (Rhodes and Liang, 2009). The motive for the establishment of mentoring programs is primarily on assisting youths in their transition into adulthood. In other cases, mentoring programs have also been established in order to curb and control delin quent behaviours. In the past decades, various mentoring programs have emerged in different parts of the world (Spencer, 2007). Moreover, the number of youths under the mentoring programs has also increased drastically (Spencer, 2007). Mentors have often entered into the mentoring programs with much enthusiasm. However, concerns on the efficacy of the mentoring programs have emerged in recent years. In particular, questions have been seen on whether or not the current state of the mentoring programs is effective and ethical (Rhodes and Liang, 2009). These questions relate to the fact that the mentor has a far greater power over the student. The power differential, in other words can be abused by the mentor. On the other, as the mentor and the student develop a closer relationship, the lines between mentor and student may be blurred (Goudreau, 2010). The National Youth Mentoring Program framework is a booklet that stipulates all that should done to ensure that all the mentoring progr ams attain the desirable goals. In relation to practitioner research, this discussion on the youth mentoring program shall now consider the foundations of the program, as well as the benefits it can bring in improving youth mentoring and in improving the healthy development of the youth. Background of youth mentoring p

Psychology Essay Example | Topics and Well Written Essays - 500 words - 13

Psychology - Essay Example The first level is self centered reasoning where a child may make a moral decision based on personal likes or dislikes, potential benefit or loss and future expectations. Preschool children or elementary school children may exhibit this level. The second level is based on the needs of the individual where the needs of the individual become important without requiring empathic feelings. Some preschool children and quite a lot of school age children exhibit this level (Eisenberg, 1989). The third level of moral reasoning is based on stereotyped or approval based reasoning in which the child exhibits moral reasoning based on what s/he understands to be the social norm of good and bad. This moral reasoning may also be used to win approval from authority figures and is used by some school age children as well as adolescents. Older school age children and many adolescents jump to the level of empathic reasoning (fourth level) in which the individual can used empathy, the idea of role playing and understanding the position of others to make moral decisions. At this level, they may be aware of the emotional response of doing good things i.e. a positive feeling and not helping others i.e. feeling guilty (Eisenberg, 1989). The fifth and sixth levels are partly internalised principles and strongly internalised principles. Under partly internalised principles the justification for the actions taken by a child are based on internalised values such as privacy, the rights of others, equality etc. and these ideas may not be clearly formed in the mind of the child. This operation level can be observed for a few adults and in some adolescents. With strongly internalised principles, the moral decisions made are always based on feelings that have been strongly internalised such as a need to improve the social conditions, or even the idea of fairness and even handedness. However, such a level is rarely found in young individuals. Overall, I feel that the model

Write about your reactions to the final part of Hamlet Essay Example for Free

Write about your reactions to the final part of Hamlet Essay At the start of the play we see Hamlet returning to Denmark from university, as he has heard the news of his farther, Old-Hamlets death. He arrives home perhaps thinking that he shall now take the place as the king of Denmark, only to discover that while he was away Claudius, his uncle and Gertrude, his mother have been wed. Therefore Claudius, not Hamlet, takes the place as King of Denmark. When Hamlet discovers this he becomes almost deranged, especially when Old-Hamlet appears to him in a form of a ghost, revealing that Claudius killed Old-Hamlet. This knowledge forces him to feel betrayed by all around him, such as the politicians that once supported his father and now show that same respect to Claudius. He feels that he can not trust his mother or Ophelia, his girlfriend. When travelling actors arrive Hamlet decides to put on a play to draw Claudius out, by seeing if he would react to a play about a brother killing a king to steal the crown. Claudius rushes out when the play is acted, showing that he is responsible for the killing of old-Hamlet. Hamlet follows quickly behind him and is about to strike Claudius down when he hears him committing his acts to god. Hamlet decides not to kill him, as when old-Hamlet was killed he did not have to commit his sins to god, so he was stuck in purgatory, a place where what you have done is weighted up, in good and bad to decide what will happen to them. Instead of killing Claudius he then proceeds to his mother to tell her of what he has found, hearing a sound he turns and thrusts a sword into a curtain, thinking that it was Claudius, only to discover that it was Polonius, Ophelias father, whom then dies. Claudius decides to send Hamlet to England to be killed, only to have Hamlet foil his plan. Hamlet returns to find while he has gone Ophelia has gone mad and has drowned her self, grief stricken he leaps into her grave. Laertes, Ophelias brother and Poloniuss son then challenges Hamlet to a duel which he Hamlet accepts. Laertes is then approached by Claudius who offers to fix the fight by poisoning his foils tip, Laertes grief stricken accepts this offer to revenge the two deaths in his family. The Ending of Hamlet sees the deaths of Laertes, Claudius, Gertrude and most importantly Hamlet. We also witness a change in the character of Hamlet, as he is now thinking less and acting more. He even mocks Laertes: Ill be your foil Laertes, in my ignorance your skill shall like astar i th darkest night stick fiery off indeed. In this scene we as an audience feel the dramatic tension, as we know all the traps lay in front of Hamlet, the poisoned foil of Laertes, and the cold goblet of wine poured by Claudius. Yet you find your self thinking that perhaps Hamlet knows that something is going on when he asks: These foils have all a length This is to command the attention of the audience to the poison tip of Laertes foil, which within the duel is held of to prolong the dramatic tension. This is the same way Hamlets action is held of with his obsession with procrastinating about the action which is to be taken to revenge his fathers death. This scene is made more dramatic by the frequent use of trumpets and kettle drums. The use of musical instruments in this way makes the environment appear more exciting. Hamlet tries to explain his actions of his recent self by asking give me your pardon sir, for I have done you wrong, but goes on to say it was not Hamlet, was his madness and also admits that his madness is poor Hamlets enemy. This excuse is not accepted by Laertes for in his terms of honour I stand aloof the only reason he is going along with the duel is to keep his name ungored, and also to revenge his fathers and sisters deaths. The use of language is of a high-class because the word ungored reminds us of the poisoned tip of the foil and what Laertes planes to do with it. Before the duel can start, Claudius plans to drink to Hamlets better breath, this is ironic as Claudius has already planed to poison Hamlets goblet of wine with a pearl. Claudius refers to this as a union, which could refer to the way in which old-Hamlet and Hamlet are to be killed, as old-Hamlet was also killed with poison that Claudius gave him. Claudius also performs this task to show the people around him that he is supporting Hamlet, so he is not thought to be guilty of Hamlets death. After the king drinks to Hamlet there is another out burst of sound as the trumpets are blown, this is also to add to the already excited atmosphere to start the duel. This leaves the audience knowing more than the victim. The next part of the text is split a series of short sentences, this is to create the speed of the duel and how the points are awarded by touches. The style of writing is used to build the dramatic tension between the two competitors. As you see Hamlet gaining the hits over Laertes, and with one hit left you start to think that Hamlet has foiled Claudiuss plan, and even avoids the poisoned goblet on two accounts. Mean while Claudius shows in this scene that he is now completely taking the place of his brother, as he speaks aside to Gertrude our son shall win. This small sentence shows what a twisted man he really is, as the words our son show as Hamlet is his brothers son and Claudius is only his uncle. Furthermore this shows that he is comfortable that his plan to poison Hamlet will be successful. Claudius is therefore shocked when Gertrude takes up Hamlets goblet to drink to him, Claudius then shouts to Gertrude, Gertrude do not drink. This line is probably by best line as it creates an atmosphere within the hall, as Claudius is pulled between saving his wife and not letting the hall of people know that he has poisoned Hamlets goblet of Hamlets wine, but in the end he is out for himself, as he does not take the goblet away from Gertrude. At this same point I think Gertrude believes all the things that Hamlet has told her earlier in the play and feels so bad that she drinks the poison, in a way this makes up for the betrayal that she committed towards her family and also the memory of Old-Hamlet. Again Hamlet dare not drink from his goblet as he wants to finish the duel first. This saves him from the poisoned goblet, therefore he only has one problem before him and thats Laertes revenge. Before the third round is started Laertes strikes out violently and wounds Hamlet, therefore poisoning him, yet to do so is almost against his conscience. In the incense of the fight, as it is no longer an honourable duel, the foils are swapped and Laertes tastes his own venom, he is justly killed by his own treachery. The Queen mean while is laid out on the floor with Claudius attending to her; she then calls out the truth about the drink! I am poisoned. At this point Hamlet knows that some treachery is around and he calls for all the doors to be locked and to seek it out. This again changes the mood of the hall and creates a room full of panic, as people are screaming and talking in worried voices. Laertes is the first to commit that he has wronged, Hamlet, thou art slain and that the treacherous instrument is in thy hand. Laertes also names who the blame should rest upon the King, the Kings to blame. At this point in the Branna film Hamlet troughs the foil at Claudius and wounds him. This causes another wave of panic to throng through the witnesses. Claudiuss last thought is for himself O yet defend me friends. This makes Hamlet angry and starts to make Claudius drink the poisoned goblet while saying all the sins Claudius has committed, incestuous, murderous, damned Dane. Again union is used to link Claudiuss death to Gertrudes, as he is united with her in death. This could also refer to the way both the brothers were killed with poison. The anger of Hamlet changes the atmosphere into a mute. Laertes then exchanges forgiveness with Hamlet, as Laertes dies. Hamlet is also feeling the poison within him as he admits to Horatio I am dead. He next turns to the rest of the witnesses in the hall; this is a much more kingly way to die thinking of his country and giving blessing to Fortinbras as the next king. When Fortinbras arrives there is once again a burst of sound, but this is not to stir excitement, it is more to command respect. When he enters he is met with the dead bodies of the royal family. When Hamlet is taken away he is carried like a soldier to the stage, as Fortinbras believes that Hamlet would have been a mighty king. I think this ending to Hamlet is a fitting ending to the play as it contains a lot of dramatic tension and a lot of action. This ending also contains a lot of honour with every thing that was wrong being righted.

Delta Modulation And Demodulation Computer Science Essay

Delta Modulation And Demodulation Computer Science Essay A modem to improve communication system performance that uses multiple modulation scheme comprising modulation technique and encoder combinations. As communication system performance and objective change, different modulation schemes may be selected. Modulation schemes may also be selected upon the communication channel scattering function estimate and the modem estimates the channel scattering function from measurements of the channels frequency (Doppler) and time (multipath) spreading characteristics. An Adaptive sigma delta modulation and demodulation technique, wherein a quantizer step size is adapted based on estimates of an input signal to the quantizer, rather than on estimates of an input signal to the modulator. A technique for digital conferencing of voice signals in systems using adaptive delta modulation (ADM) with an idle pattern of alternating 1s and 0s has been described. Based on majority logic, it permits distortion-free reception of voice of a single active subscriber by all the other subscribers in the conference. Distortion exists when more than one subscriber is active and the extent of this distortion depends upon the type of ADM algorithm that has been used. An LSI oriented system based on time sharing of a common circuit by a number of channels has been implemented and tested. This technique, with only minor changes in circuitry, handles ADM channels that have idle patterns different from alternating single 1s and 0s. This method used for noise reduction. The modulator factor does not require a large amount of data to be represented. Representation is based upon a frequency domain function having particular characteristics. A preferred embodiment of the invention incorporates transform or sub band filtered signals which are transmitted as a modulated analog representation of a local region of a video signal. The modulation factor reflects the particular characteristic. Side information specifies the modulation factor 1.2. Aim: Digital techniques to wirelessly communicate voice information. Wireless environments are inherently noisy, so the voice coding scheme chosen for such an application must be robust in the presence of bit errors. Pulse Coded Modulation (PCM) and its derivatives are commonly used in wireless consumer products for their compromise between voice quality and implementation cost. Adaptive Delta Modulation (ADM) is another voice coding scheme, a mature technique that should be considered for these applications because of its bit error robustness and its low implementation cost. Bandpass modulation techniques encode information as the amplitude, fre ­quency, phase, or phase and amplitude of a sinusoidal carrier. These band ­pass modulation schemes are known by their acronyms ASK (amplitude shift keying), FSK (frequency shift keying), PSK (phase shift keying), and QAM (qua ­ternary amplitude modulation), where keying or modulation is used to indicate that a carrier signal is modified in some manner. The carrier is a sinusoidal signal that is initially devoid of any information. The purpose of the carrier is to translate essentially a baseband information signal to a frequency and wavelength that can be sent with a guided or propagating electro ­magnetic (EM) wave. Bandpass ASK is similar to baseband pulse amplitude modulation (PAM) in Chapter 2, Baseband Modulation and Demodulation, but FSK, PSK, and DM are new non-linear modulation techniques. ASK, FSK, and PSK can be readily extended to multiple level (M-ary) signaling and demodulated coherently or non-coherently. The optimum receiver for bandpass symmetrical or asymmetrical sig ­nals is the correlation receiver, which is developed for baseband signals in Chapter 2. Coherent demodulation uses a reference signal with the same frequency and phase as the received signal. No coherent demodulation of bandpass signaling may use differential encoding of the information to derive the reference signal in the correlation receiver. The observed bit error rate (BER) for a single, in a MATLAB simulation for several bandpass digital communication systems with coherent and non coherent correlation receivers is compared to the theoretical probability of bit error (Pb). Digital communication systems are subject to performance degrada ­tions with additive white Gaussian noise (AWGN). MATLAB simulations of bandpass communication systems are used to investigate the effect upon BER of the performance of the correlation receiver, the reduction in BER with Gray-coding of M-ary data, and binary and quaternary differential signaling. MATLAB simulations of such bandpass digital communication systems and investigations of their characteristics and performance are provided here. These simulations confirm the theoretical expectation for Pb and are the starting point for the what-ifs of bandpass digital communication system design. Finally, the constellation plot depicts the demodulated in-phase and quadra ­ture signals of complex modulation schemes in the presence of AWGN. The opti ­mum decision regions are shown, and the observed BER performance of the bandpass digital communication system can be qualitatively assessed. Delta Modulation: Delta modulation is also abbreviated as DM or Ά-modulation. It is a technique of conversion from an analog-to-digital and digital-to-analog signal. If we want to transmit the voice we use this technique. In this technique we do not give that much of importance to the quality of the voice. DM is nothing but the simplest form of differential pulse-code modulation (DPCM). But there is some difference between these two techniques. In DPCM technique the successive samples are encoded into streams of n-bit data. But in delta modulation, the transmitted data is reduced to a 1-bit data stream. Main features: * The analog signal is similar as a series of segments. * To find the increase or decrease in relative amplitude, we should compare each and every segment of the approximated signal with the original analog wave. * By this comparison of original and approximated analog waves we can determine the successive bits for establishing. * only the change of information is sent, that is, only an increase or decrease of the signal amplitude from the previous sample is sent whereas a no-change condition causes the modulated signal to remain at the same 0 or 1 state of the previous sample. By using oversampling techniques in delta modulation we can get large high signal-to-noise ratio. That means the analog signal is sampled at multiple higher than the Nyquist rate. Principle In delta modulation, it quantizes the difference between the current and the previous step rather than the absolute value quantization of the input analog waveform, which is shown in fig 1. Fig. 1 Block diagram of a Ά-modulator/demodulator The quantizer of the delta modulator converts the difference between the input signal and the average of the previous steps. The quantizer is measured by a comparator with reference to 0 (in 2- level quantizer), and its output is either 1 or 0. 1 means input signal is positive and 0 means negative. It is also called as a bit-quantizer because it quantizes only one bit at a time. The output of the demodulator rises or falls because it is nothing but an Integrator circuit. If 1 received means the output raises and if 0 received means output falls. The integrator internally has a low-pass filter it self. Transfer Characteristics A signum function is followed by the delta modulator for the transfer characteristics. It quantizes only levels of two number and also for at a time only one-bit. Output signal power In delta modulation amplitude it is does not matter that there is no objection on the amplitude of the signal waveform, due to there is any fixed number of levels. In addition to, there is no limitation on the slope of the signal waveform in delta modulation. We can observe whether a slope is overload if so it can be avoided. However, in transmitted signal there is no limit to change. The signal waveform changes gradually. Bit-rate The interference is due to possibility of in either DM or PCM is due to limited bandwidth in communication channel. Because of the above reason DM and PCM operates at same bit-rate. Noise in Communication Systems Noise is probably the only topic in electronics and telecommunications with which every-one must be familiar, no matter what his or her specialization. Electrical disturbances interfere with signals, producing noise. It is ever present and limits the performance of most systems. Measuring it is very contentious almost everybody has a different method of quantifying noise and its effects. Noise may be defined, in electrical terms, as any unwanted introduction of energy tending to interfere with the proper reception and reproduction of transmitted signals. Many disturbances of an electrical nature produce noise in receivers, modifying the signal in an unwanted manner. In radio receivers, noise may produce hiss in the loudspeaker output. In television receivers snow, or confetti (colored snow) becomes superimposed on the picture. In pulse communications systems, noise may produce unwanted pulses or perhaps cancel out the wanted ones. It may cause serious mathematical errors. Noise can l imit the range of systems, for a given transmitted power. It affects the sensitivity of receivers, by placing a limit on the weakest signals that can be amplified. It may sometimes even force a reduction in the bandwidth of a system. Noise is unwanted electrical or electromagnetic energy that degrades the quality of signals and data. Noise occurs in digital and analog systems, and can affect files and communications of all types, including text, programs, images, audio, and telemetry. In a hard-wired circuit such as a telephone-line-based Internet hookup, external noise is picked up from appliances in the vicinity, from electrical transformers, from the atmosphere, and even from outer space. Normally this noise is of little or no consequence. However, during severe thunderstorms, or in locations were many electrical appliances are in use, external noise can affect communications. In an Internet hookup it slows down the data transfer rate, because the system must adjust its speed to match conditions on the line. In a voice telephone conversation, noise rarely sounds like anything other than a faint hissing or rushing. Noise is a more significant problem in wireless systems than in hard-wired systems. In general, noise originating from outside the system is inversely proportional to the frequency, and directly proportional to the wavelength. At a low frequency such as 300 kHz, atmospheric and electrical noise are much more severe than at a high frequency like 300 MHz. Noise generated inside wireless receivers, known as internal noise, is less dependent on frequency. Engineers are more concerned about internal noise at high frequencies than at low frequencies, because the less external noise there is, the more significant the internal noise becomes. Communications engineers are constantly striving to develop better ways to deal with noise. The traditional method has been to minimize the signal bandwidth to the greatest possible extent. The less spectrum space a signal occupies, the less noise is passed through the receiving circuitry. However, reducing the bandwidth limits the maximum speed of the data that can be delivered. Another, more recently developed scheme for minimizing the effects of noise is called digital signal processing (DSP). Using fiber optics, a technology far less susceptible to noise, is another approach. Sources of Noise As with all geophysical methods, a variety of noises can contaminate our seismic observations. Because we control the source of the seismic energy, we can control some types of noise. For example, if the noise is random in occurrence, such as some of the types of noise described below, we may be able to minimize its affect on our seismic observations by recording repeated sources all at the same location and averaging the result. Weve already seen the power of averaging in reducing noise in the other geophysical techniques we have looked at. Beware, however, that averaging only works if the noise is random. If it is systematic in some fashion, no amount of averaging will remove it. The noises that plague seismic observations can be lumped into three categories depending on their source.  · Uncontrolled Ground Motion This is the most obvious type of noise. Anything that causes the ground to move, other than your source, will generate noise. As you would expect, there could be a wid e variety of sources for this type of noise. These would include traffic traveling down a road, running engines and equipment, and people walking. Other sources that you might not consider include wind, aircraft, and thunder. Wind produces noise in a couple of ways but of concern here is its affect on vegetation. If you are surveying near trees, wind causes the branches of the trees to move, and this movement is transmitted through the trees and into the ground via the trees roots. Aircraft and thunder produce noise by the coupling of ground motion to the sound that we hear produced by each. Adaptive Delta Modulation (ADM) Another type of DM is Adaptive Delta Modulation (ADM). In which the step-size isnt fixed. The step-size becomes progressively larger when slope overload occurs. When quantization error is increasing with expensive the slope error is also reduced by ADM. By using a low pass filter this should be reduced. The basic delta modulator was studied in the experiment entitled Delta modulation. It is implemented by the arrangement shown in block diagram form in Figure Figure: Basic Delta Modulation A large step size was required when sampling those parts of the input waveform of steep slope. But a large step size worsened the granularity of the sampled signal when the waveform being sampled was changing slowly. A small step size is preferred in regions where the message has a small slope. This suggests the need for a controllable step size the control being sensitive to the slope of the sampled signal. This can be implemented by an arrangement such as is illustrated in Figure Fig: An Adaptive Delta Modulator The gain of the amplifier is adjusted in response to a control voltage from the SAMPLER, which signals the onset of slope overload. The step size is proportional to the amplifier gain. This was observed in an earlier experiment. Slope overload is indicated by a succession of output pulses of the same sign. The TIMS SAMPLER monitors the delta modulated signal, and signals when there is no change of polarity over 3 or more successive samples. The actual ADAPTIVE CONTROL signal is +2 volt under normal conditions, and rises to +4 volt when slope overload is detected. The gain of the amplifier, and hence the step size, is made proportional to this Control voltage. Provided the slope overload was only moderate the approximation will catch up with the wave being sampled. The gain will then return to normal until the sampler again falls behind. Comparison of PCM and DM When coming to comparison of Signal-to-noise ratio DM has larger value than signal-to-noise ratio of PCM. Also for an ADM signal-to-noise ratio when compared to Signal-to-noise ratio of companded PCM. Complex coders and decoders are required for powerful PCM. If to increase the resolution we require a large number of bits per sample. There are no memories in Standard PCM systems each sample value is separately encoded into a series of binary digits. An alternative, which overcomes some limitations of PCM, is to use past information in the encoding process. Delta modulation is the one way of doing to perform source coding. The signal is first quantized into discrete levels. For quantization process the step size between adjacent samples should be kept constant. From one level to an adjacent one the signal makes a transition of transmission. After the quantization operation is done, sending a zero for a negative transition and a one for a positive transition the signal transmission is achieved. We can observe from this point that the quantized signal must change at each sampling point. The transmitted bit train would be 111100010111110 for the above case. The demodulator for a delta-modulated signal is nothing but a staircase generator. To increments the staircase in positively a one should be received. For negative increments a zero should be receive. This is done by a low pass filter in general. The main thing for the delta modulation is to make the right choice of step size and sampling period. A term overloading is occurred when a signal changes randomly fast for the steps to follow. The step size and the sampling period are the important parameters. In modern consumer electronics short-range digital voice transmission is used. There are many products which uses digital techniques. Such as cordless telephones, wireless headsets (for mobile and landline telephones), baby monitors are few of the items. This digital techniques used Wirelessly communicate voice information. Due to inherent noise in wireless environments the Voice coding scheme chosen. For such an application the presence of robust bit errors must be. In the presence of bit errors Pulse Coded Modulation (PCM) and its derivatives are commonly used in wireless consumer products. This is due to their compromise between voice quality and implementation cost, but these are not robust schemes. Another important voice coding scheme is Adaptive Delta Modulation (ADM). It is a mature technique for consideration for these types of applications due to its robustness in bit error and its low implementation cost. To quantize the difference between the current sample and the predicted value of the next Sample ADM is used. It uses a variable called step height which is used to adjustment of the prediction value of the next sample. For the reproduction of both slowly and rapidly changing input signals faithfully. In ADM, the representation of each sample is one bit (i.e. 1 or 0). It does not require any data framing for one-bit-per-sample stream to minimizing the workload on the host microcontroller. In any digital wireless application there should be Bit errors. In ideal environment most of the voice coding techniques are provided which are good in quality of audio signals. The main thing is to provide good audio signals in everyday environment, there may be a presence of bit errors. For different voice coding methods and input signals the traditional performance metrics (e.g. SNR) does not measure accurately in audio quality. . Mean Opinion Score (MOS) testing is the main important parameter which overcomes the limitations of other metrics by successfully in audio quality. For audio quality the MOS testing is used. It is a scale of 1 to 5 which tells the audio quality status. In there 1 represents very less (bad) speech quality and 5 represents excellent speech quality. A toll quality speech has a MOS score of 4 or higher than it. The audio quality of a traditional telephone call has same MOS value as above. The below graphs shows the relationship between MOS scores and bit errors for three of the most common voice coding schemes. Those are CVSD, ÃŽÂ ¼-law PCM, and ADPCM. A continuously Variable Slope Delta (CVSD) coding is a member of the ADM family in voice coding schemes. The below graph shows the resulted audio quality (i.e. MOS score). All three schemes explain the number of bit errors. As the no of bit errors increases the graph indicates that ADM (CVSD) sounds better than the other schemes which are also increase. In an ADM design error detection and correction typically are not used because ADM provides poor performance in the presence of bit errors. This leads to reduction in host processor workload (allowing a low-cost processor to be used). The superior noise immunity significantly reduced for wireless applications in voice coding method. The ADM is supported strongly by workload for the host processor. The following example shows the benefits of ADM for wireless applications and is demonstrated. For a complete wireless voice product this low-power design is used which includes all of the building blocks, small form-factor, including the necessary items. ADM voice codec Microcontroller RF transceiver Power supply including rechargeable battery Microphone, speaker, amplifiers, etc. Schematics, board layout files, and microcontroller code written in C. Delta modulation (DM) may be viewed as a simplified form of DPCM in which a two level (1-bit) quantizer is used in conjunction with a fixed first-order predictor. The block diagram of a DM encoder-decoder is shown below.   The dm_demo shows the use of Delta Modulation to approximate input sine wave signal and a speech signal that were sampled at 2 KHz and 44 KHz, respectively. The source code file of the MATLAB code and the out put can be viewed using MATLAB. Notice that the approximated value follows the input value much closer when the sampling rate is higher. You may test this by changing sampling frequency, fs, value for sine wave in dm_demo file. Since DM (Delta Modulator) approximate a waveform Sa(t) by a linear staircase function, the waveform Sa(t) must change slowly relative to the sampling rate. This requirement implies that waveform Sa(t) must be oversampled, i.e., at least five times the Nyquist rate. Oversampling means that the signal is sampled faster than is necessary. In the case of Delta Modulation this means that the sampling rate will be much higher than the minimum rate of twice the bandwidth. Delta Modulation requires oversampling in order to obtain an accurate prediction of the next input. Since each encoded sample contains a relatively small amount of information Delta Modulation systems require higher sampling rates than PCM systems. At any given sampling rate, two types of distortion, as shown below limit the performance of the DM encoder.   Slope overload distortion: This type of distortion is due to the use of a step size delta that is too small to follow portions of the waveform that have a steep slope. It can be reduced by increasing the step size. Granular noise: This results from using a step size that is too large too large in parts of the waveform having a small slope. Granular noise can be reduced by decreasing the step size. Even for an optimized step size, the performance of the DM encoder may still be less satisfactory. An alternative solution is to employ a variable step size that adapts itself to the short-term characteristics of the source signal. That is the step size is increased when the waveform has a step slope and decreased when the waveform has a relatively small slope. This strategy is called adaptive DM (ADM). Block Diagram Adaptive Delta Modulation for Audio Signals: While transmitting speech for e.g. telephony the transfer rate should be kept as small as possible to save bandwidth because of economic reason. For this purpose Delta Modulation, adaptive Delta modulation, Differential Pulse-Code modulation is used to compress the data. In this different kind of Delta modulations and Differential Pulse Code modulations (DPCM) were realized to compress audio data. At first the principal of compressing audio data are explained, which the modulations based on. Mathematical equations (e.g. Auto Correlation) and algorithm (LD recursion) are used to develop solutions. Based on the mathematics and principals Simulink models were implemented for the Delta modulation, Adaptive Delta modulation as well as for the adaptive Differential Pulse Code modulation. The theories were verified by applying measured signals on these models. Signal-to-noise ratio Signal-to-noise ratio (often abbreviated SNR or S/N) is an electrical engineering measurement, also used in other fields (such as scientific measurement or biological cell signaling), defined as the ratio of a signal power to the noise power corrupting the signal. A ratio higher than 1:1 indicates more signal than noise. In less technical terms, signal-to-noise ratio compares the level of a desired signal (such as music) to the level of background noise. The higher the ratio, the less obtrusive the background noise is. In engineering, signal-to-noise ratio is a term for the power ratio between a signal (meaningful information) and the background noise: where P is average power. Both signal and noise power must be measured at the same and equivalent points in a system, and within the same system bandwidth. If the signal and the noise are measured across the same impedance, then the SNR can be obtained by calculating the square of the amplitude ratio: where A is root mean square (RMS) amplitude (for example, typically, RMS voltage). Because many signals have a very wide dynamic range, SNRs are usually expressed in terms of the logarithmic decibel scale. In decibels, the SNR is, by definition, 10 times the logarithm of the power ratio: Cutoff rate For any given system of coding and decoding, there exists what is known as a cutoff rate R0, typically corresponding to an Eb/N0 about 2 dB above the Shannon capacity limit. The cutoff rate used to be thought of as the limit on practical error correction codes without an unbounded increase in processing complexity, but has been rendered largely obsolete by the more recent discovery of turbo codes. Bit error rate In digital transmission, the bit error rate or bit error ratio (BER) is the number of received binary bits that have been altered due to noise and interference, divided by the total number of transferred bits during a studied time interval. BER is a unit less performance measure, often expressed as a percentage number. As an example, assume this transmitted bit sequence: 0 1 1 0 0 0 1 0 1 1, And the following received bit sequence: 0 0 1 0 1 0 1 0 0 1, The BER is in these case 3 incorrect bits (underlined) divided by 10 transferred bits, resulting in a BER of 0.3 or 30%. The bit error probability pe is the expectation value of the BER. The BER can be considered as an approximate estimate of the bit error probability. The approximation is accurate for a long studied time interval and a high number of bit errors. Factors affecting the BER In a communication system, the receiver side BER may be affected by transmission channel noise, interference, distortion, bit synchronization problems, attenuation, wireless multipath fading, etc. The BER may be improved by choosing a strong signal strength (unless this causes cross-talk and more bit errors), by choosing a slow and robust modulation scheme or line coding scheme, and by applying channel coding schemes such as redundant forward error correction codes. The transmission BER is the number of detected bits that are incorrect before error correction, divided by the total number of transferred bits (including redundant error codes). The information BER, approximately equal to the decoding error probability, is the number of decoded bits that remain incorrect after the error correction, divided by the total number of decoded bits (the useful information). Normally the transmission BER is larger than the information BER. The information BER is affected by the strength of the forward error correction code. CHAPTER II Pulse-code modulation: Pulse-code modulation (PCM) is a method used to digitally represent sampled analog signals, which was invented by Alec Reeves in 1937. It is the standard form for digital audio in computers and various Compact Disc and DVD formats, as well as other uses such as digital telephone systems. A PCM stream is a digital representation of an analog signal, in which the magnitude of the analogue signal is sampled regularly at uniform intervals, with each sample being quantized to the nearest value within a range of digital steps. PCM streams have two basic properties that determine their fidelity to the original analog signal: the sampling rate, which is the number of times per second that samples are taken; and the bit-depth, which determines the number of possible digital values that each sample can take. Digitization as part of the PCM process In conventional PCM, the analog signal may be processed (e.g. by amplitude compression) before being digitized. Once the signal is digitized, the PCM signal is usually subjected to further processing (e.g. digital data compression). PCM with linear quantization is known as Linear PCM (LPCM). Some forms of PCM combine signal processing with coding. Older versions of these systems applied the processing in the analog domain as part of the A/D process; newer implementations do so in the digital domain. These simple techniques have been largely rendered obsolete by modern transform-based audio compression techniques. * DPCM encodes the PCM values as differences between the current and the predicted value. An algorithm predicts the next sample based on the previous samples, and the encoder stores only the difference between this prediction and the actual value. If the prediction is reasonable, fewer bits can be used to represent the same information. For audio, this type of encoding reduces the number of bits required per sample by about 25% compared to PCM. * Adaptive DPCM (ADPCM) is a variant of DPCM that varies the size of the quantization step, to allow further reduction of the required bandwidth for a given signal-to-noise ratio. * Delta modulation is a form of DPCM which uses one bit per sample. In telephony, a standard audio signal for a single phone call is encoded as 8000 analog samples per second, of 8 bits each, giving a 64 kbit/s digital signal known as DS0. The default signal compression encoding on a DS0 is either ÃŽÂ ¼-law (mu-law) PCM (North America and Japan) or A-law PCM (Europe and most of the rest of the world). These are logarithmic compression systems where a 12 or 13-bit linear PCM sample number is mapped into an 8-bit value. This system is described by international standard G.711. An alternative proposal for a floating point representation, with 5-bit mantissa and 3-bit radix, was abandoned. Where circuit costs are high and loss of voice quality is acceptable, it sometimes makes sense to compress the voice signal even further. An ADPCM algorithm is used to map a series of 8-bit  µ-law or A-law PCM samples into a series of 4-bit ADPCM samples. In this way, the capacity of the line is doubled. The technique is detailed in the G.726 standard. Later it was found that even further compression was possible and additional standards were published. Pulse code modulation (PCM) data are transmitted as a serial bit stream of binary-coded time-division multiplexed words. When PCM is transmitted, pre modulation filtering shall be used to confine the radiated RF spectrum. These standards define pulse train structure and system design characteristics for the implementation of PCM telemetry formats. Class Distinctions and Bit-Oriented Characteristics The PCM formats are divided into two classes for reference. Serial bit stream characteristics are described below prior to frame and word orient

personal narrative Essay -- essays research papers

The Gift After what seemed like an eternity of rigorous tests and dealing with the painful longing of wanting to hold a precious baby of my own in my arms, it happened; my dreams at long last came true. I was pregnant! But something happened; I felt my world come crashing down. The thought of bringing another life into this world terrified me. After marriage, my husband and I immediately wanted to start a family. A year or so went by and still nothing, no baby. I decided to check myself out to see if anything was wrong. I went through all the normal tests to see if there were any problems. The doctors couldn’t find any concrete explanation why I wasn’t able to conceive. As a last resource, before getting into more invasive measures, my doctor wanted me to try a fertility pill called Clomid. Figuring I didn’t have anything to loose, I started taking the pills. A few months after taking Clomid, I realized I was feeling a bit strange. I was more tired then I normally felt. I decided to take a pregnancy test. Assuming I was going to get the same negative result, I take the test, walk away and gather my thoughts. Hoping and praying for a different outcome that I had become accustomed to. I walked back to read the results. Expecting to see a negative test, I stare at the test in disbelief. Two pink lines! I blink my eyes to make sure I am not seeing things, it was true. A positive pregnancy test, some...

Toxic Waste Sites in Texas Essay -- essays research papers

Major Toxic Waste Sites in Texas When thinking about the most polluted states in our country, California and New York instantly pop into our mind. What most people don’t know, however, is that Texas now ranks number one in most categories of pollution. Whether it be increased emissions from refineries in Beaumont, large pits filled with contamination at Kelley Air Force Base, or polluted water at Lake Sam Rayburn, Texas has more than its fair share of toxic waste. Exxon/Mobil, one of the nation’s leading oil producers, has its main refinery located in Beaumont, Texas. Each year, the residents of Beaumont/Port Arthur have to contend with the 39,000 pounds of pollution spewed each year by the Exxon refinery. Exxon’s emissions are 385% above the state refinery average. In 1999, the Texas Natural Resources Conservation Committee (TNRCC) allowed the plant to increase their emissions, without allowing the public to have a say in the matter. Interestingly, 95% of the people living near the plant are of African American descent and are in the poverty range. Some believe that this, along with the lack of education in the area, allows Exxon to get away with such high emissions. Residents in nearby neighborhoods have been complaining of headaches, nausea, eye, and throat irritation for years. Since 1997, Mobil has repeatedly violated health standards in its emissions of two key air pollutants: sulfur dioxide and hydrogen sulfide, These â€Å"rotten egg† smells are so strong, one can smell it through a car driving past the refinery. After numerous complaints and one record of a refinery worker becoming unconscious because of the fumes, the EPA awarded Exxon with a $100,000 environmental justice grant in October of 1998. Hopefully, Exxon has put the money to good use and cleaned up their emissions. Kelly Air Force Base (KAFB) in San Antonio has been one of the Air Force's major aircraft maintenance facilities since the 1950s. Located on 4000 acres and surrounded by residential neighborhoods, KAFB warehouses and maintains aircraft, jet engines, and nuclear materials for worldwide distribution. Activities at the base can generate as much as 282,000 tons of hazardous waste per year, all in close range to the neighboring communities. One day, a woman living near the base noticed a man dumping waste into an open pit in... ...d. As of July 2001, nothing has been done to change the water standards for the Donahue paper mill. This is a sad thing, not only for the residents that live on the lake, but also for the thousands of fish and wildlife that are killed each year. All three of these examples prove that pollution is happening in Texas and that it is important for residents to get involved if they want a change to happen. Sometimes, even governmental agencies cannot stop pollution. We must take care of our natural resources, especially land and water, because they are non-renewable. We want our state to be clean for our grandchildren, great grandchildren, and great-great grandchildren. This will not happen unless residents of these toxic waste sites take action and let their voices be heard. Besides, whatever happened to the slogan, â€Å"Don’t Mess With Texas?† References: 1). Texas Toxic Tour, http://www.txpeer.org 2). Texas Parks and Wildlife Department, "1999 Report of Sam Rayburn Task Force," March 2000, http://www.anglersresort.com/lake.htm 3). Southwest Public Workers' Union, "North Kelly Gardens Community Health Survey near Kelly AFB, Texas," Revised Edition, 10/23/97, p. 3.

Apple’s iphone – Not “made in America”

1) What is meant by globalization of human capital? Is this inevitable as firms increase their global operations? Globalization of human capital implies that people are moved out of their native country for employment in various fields. Since there are many companies around the globe and have branches in other countries, qualified people get an opportunity to move out and work. It is inevitable since globalization is established and the companies use the skills, labor, talent and knowledge as a part of globalization of human capital.2) How does this case illustrate the threats and opportunities facing global companies in developing their strategies? The main threat is when president Obama asked Steve job about reduction of job opportunities in United states and giving job in other countries, which made a feel of threat in their own country. And also many suicides at Foxconn lead a negative impression on Apple. The opportunities faced by them are high profit of $ 321 per i phone. It s hows the profit of a global company.3) Comment on Apple executives assertion that the company's only obligation is making the best product possible. â€Å"we do not have have any obligation o solve America's problems† I think it is really harsh to say these words. Everyone should have some obligation towards their country. But this is business and as an executive he is right he should always think about the growth and quality of the product. And should make maximum profit from low cost. So I think he is right.4) Who are the stakeholders in this situation and what, if any, obligations do they have? The main stakeholders are Apple company, Foxconn, and the government. All of these have obligations. Since Apple is a brand company and all expect best from them it is their obligation to be faithful and best quality provider to the consumers and also to the workers who work 24 hours for them. It is same for Foxconn too. They should be concern about the workers they should get the a dequate pay and rest. Also, government  should safe guard the people of each country from any type of pressure.5) How much extra are you prepared to pay for an iphone if assembled in the United states? I think I will not pay even a single penny extra to buy an iphone since they have a profit of $321 now itself. That is too much profit. I recommend they should decrease the rate of the phone. Some other product made in USA is not that expensive so the iphone should also be a little lower than now. After all, it is a phone although it has many application also it is not expensive enough to make it.6) How much extra are you prepared to pay for an iphone if assembled in China but under better conditions and pay? What kind of trade -off would you make? I have the same opinion as I said for United states. Better conditions and pay rights of workers and it does not mean the price should be increased since the already have a good profit. And it is the right thing to provide better conditio ns and better pay. We can also think about globalization of human capital to United states.7) To what extend do you think the negative media coverage has affected Apple's recent decision to ask the FLA to do an assessment and the subsequent decision by Foxconn to raise some salaries? What do you think will happen now?Since everyone knows about the case I think they will be more careful and take a favorable decision so as to protect the workers. It is sure that the negative media coverage has affected Apple's image very badly and so they asked for a FLA assessment. Foxconn on other hand was squeezing the workers to do more work with little pay and the suicide which occurred made made them into trouble and they increased the wages to save their face and I think they have to be very careful in future by providing good environment to work with a descent pay.