The Lost Symbol Review Essay Example

The Lost Symbol Review Paper Essay on The Lost Symbol Belief in anything by itself is not more religion. Faith, as they say, no dead case. Therefore, religion begins only where faith and, even more precisely, belief system reinforced by a cult behaviors and necessarily systematic. Otherwise the parishioners are zahozhanami or prohozhanami and scientific statistics the one that looks and evaluates, not wishful thinking, considering such Zakhozhaev not as true believers, as well as natural atheists . Unexpectedly, is not it? This spontaneous atheism knew example Belinsky (see. The letter to Gogol). And all this is because the faith, for example, in the heel of his own, well, or there some code does not fundamentally inferior to any other arbitrarily systematic fantasy, pagan, Christian Mixing religion with science sorry its like retrogradanaya amnesia. Although there are rational in this important moment interest: any social illusions of this sort of Russians are very in price from puppeteers for obvious reasons: it is easier to cop e with the electorate. While it is true noticed that both religion and science forms of social consciousness, but completely different, they are oriented in different ways: the first in the truth, and the second in the interests of different social groups: That old song, renunciation songs, tales about the joys of heaven, She lull silly people, that they did not ask for bread, I know the melody, I know the text and the authors know very well: They drank wine of the house, preaching in public water. Heinrich Heine (1797-1856). (Song of the beggar girl harpist. Translated by Levik) The Lost Symbol Review Essay Example The Lost Symbol Review Paper Essay on The Lost Symbol We must assume that the commercials in 2025. Roberg Langdon finally gets up to Russia. He was still in appearance can be given early forties (medicine marches forward by leaps and bounds, and the first at each step kicks course it Langdon, he might even have and rejuvenate years to thirty, but his occupation is too undignified views) at the beginning we will tell about the list of cities where already gone before the great adventurer Paris, Rome, Washington, Berlin, Istanbul, Beijing, Mexico city, Kyoto, etc. everywhere What to look for Robert ubiquitous in Russia? Well, lets say the notorious nuclear suitcase somewhere in the library of Ivan the Terrible To help him be the girl of average years, a major special on this most libraries a parallel course goes to the library during the fourth hour of the night a terrible maniac, embodies at once all the horrors of American housewives at a time (even then I just do not have enough imagination to imagine defer selection to the author ). First encounter maniac and Langdon occurs through Ghastlier slaughter (and do not think even that he deliberately waited for Roberts arrival in Moscow, not at all, just a coincidence) in the style of most of Ivan the Terrible (and let the fans of the fourth Vasilyevich continue to make noise, he was a kind-hearted people from America this just do not see) someone such. For maniac and Langdon, but always one step behind (the affair should be the place to be) should be the FSB in the face of Porfiry Petrovich. At the end there all along, apparently in the mausoleum, which is But no, we will not disclose all the secrets in advance But in the end what. Dan Browns new feature: the end is something along the length exceeding the epilogue of War and Peace, where we detail to tell the truth about the meaning of life and the general guide to the right path abruptly than any Coelho. It is a pity that while you can read only about Washington. But never mind, we hope that we have all come and Dan !!!

Ofdm-Based Cooperative Communications in a Single Path Relay Network and a Multiple Path Relay Network Essays

Ofdm-Based Cooperative Communications in a Single Path Relay Network and a Multiple Path Relay Network Essays Ofdm-Based Cooperative Communications in a Single Path Relay Network and a Multiple Path Relay Network Essay Ofdm-Based Cooperative Communications in a Single Path Relay Network and a Multiple Path Relay Network Essay In this thesis, we investigate cooperation by applying OFDM signals to cooperative relay networks. We consider the single path relay network and the multiple path relay network. Using the amplify-and-forward relay algorithm, we derive the input-output relations and mutual informations of both networks. Using a power constraint at each relay, we consider two relay power allocation schemes.The ? rst is constant gain allocation, where the amplifying gain used in the amplify-and-forward algorithm is constant for all subcarriers. The second is equal power allocation, where each subcarrier transmits the same power. The former scheme does not require CSI (channel state information), while the latter one does. We simulate the mutual informations using the two relay power allocation schemes. Results indicate that equal power allocation gives a slightly higher mutual information for the single path relay network. For the multiple path network, the mutual information is practically the same for both schemes.Using the decode-and-forward relay algorithm, we derive the inputoutput relations for both networks. The transmitter and each relay are assumed to have uniform power distributions in this case. We simulate the BER (bit error rate) and WER (word error rate) performance for the two networks using both the amplify-and-forward and decode-and-forward relay algorithms. For the single path relay network, amplify-andforward gives very poor performance, because as we increase the distance between the transmitter and receiver (and thus, add more relays), more noise and channel distortion enter the system. Decode-and-forward gives signi? antly better performance because noise and channel distortion are eliminated at each relay. For the multiple path relay network, decode-and-forward again gives better performance than amplify-and-forward. However, the performance gains are small compared to the single path relay network case.Therefore, amplify-and-forward may be a more attractive choice due to its lower complexity. ix CHAPTER I INTRODUCTION Wireless communication systems inherently su? er from multipath propagation and channel fading. Time diversity, space diversity, frequency diversity [8], and combinations of the three are traditionally used to combat these e? cts. More recently, relays situated between the transmitter and receiver are also being exploited to improve information transfer. The relays are a network of transceiver nodes between the transmitter and receiver that facilitate the transfer of information. Thus, the relay network as a whole is an equivalent channel between the transmitter and receiver. This type of scheme is known as cooperation or cooperative communications in the literature because the relay network is cooperating with the transmitter and receiver to improve performance.In this thesis, we consider cooperation in the context of orthogonal frequency division multiplexing (OFDM) systems. 1. 1 Motivation The motivation for cooperati ve communications is obvious. Cellular phones, laptops and personal digital assistants (PDAs) are just three examples of wireless devices that are very prevalent today. These transceiver devices usually communicate independently from each other. As the authors in [6] note, this is wasting the broadcast nature of the wireless medium.For example, if a base station is communicating with a user’s cellular phone, his/her nearby laptop has the capability to receive the base station’s signals and relay them to the phone, improving the end-to-end performance of the base station-phone link. Unfortunately, laptops and cellular phones today are not designed this way. This illustration is an example of an ad-hoc network, where nodes spontaneously recognize each other and cooperate. In this thesis, we investigate structured networks, where each node knows the existence of all the other nodes a priori.Whether the nodes discover each other through an ad-hoc algorithm or they are pre- programmed to have this knowledge is beyond the scope 1 of this thesis. 1. 2 Related Literature The authors in [10], [11] have considered cooperation between intra-cell users in a code division multiple access (CDMA) cellular network. In this case, cooperation results in higher data rates and leads to lower power requirements for users. As well, the system is less sensitive to channel variations. Relaying of signals, as viewed from the physical layer, is not a trivial issue. The authors in [5], [6], [7] have provided several physical layer relay algorithms.These include amplifyand-forward, decode-and-forward and selection relaying. In amplify-and-forward, a node ampli? es its receive symbol, subject to a power constraint, before re-transmitting to the next node. This algorithm is obviously with low complexity. In decode-and-forward, a node fully decodes a symbol, re-encodes it and then re-transmits it. In other words, this scheme attempts to eliminate channel distortion and noise at each node. In selection relaying, a node only re-transmits a symbol if the measured receiving channel gain is above a certain threshold.If the threshold is not reached, the relay requests a re-transmission from the sender. In networking terminology, this is a type of automatic repeat request (ARQ) scheme. The authors in [6], [7] have investigated cooperation for the classical relay channel introduced in [1], [7]. Outage probability is used to characterize performance. Outage probability is the probability that the mutual information between the transmitter and receiver does not reach a certain throughput threshold. Without cooperation, the outage probability decays proportionally with 1/SNR, where SNR is the signal-to-noise ratio of the channel.Using cooperation and the amplify-and-forward scheme, the outage probability decays proportionally with 1/SNR2 , achieving full diversity. This results in large power savings for the transmitter. The authors in [3], [4] have investigated coo peration for a single path of relays connected in series. The motivation for this network structure is that broader wireless coverage can be achieved, while still maintaining a low power constraint at the transmitter. The authors consider analog relaying and digital relaying as two possible relay algorithms. These are 2 equivalent to the amplify-and-forward and decode-and-forward algorithms, respectively.A power budget is considered where each packet travelling through the network is only allowed to consume a total ? xed amount of power. As well, each node has a certain transmit power limit. The outage probability is then minimized by allocating power among the relay network under these power constraints. This power allocation accounts for the channel conditions in the network in order to achieve the optimal outage probability. Simulations indicate that 2 dB of total power can be saved for 5 relays by using optimal power allocation instead of uniform power allocation. This is for th e decode-and-forward case.However, at high SNR values, the decode-and-forward case approximates the amplify-and-forward case. The authors in [13] have investigated cooperation for multiple paths of relays connected in parallel. In the conventional scheme, all relays participate using amplify-and-forward. This is called all-participate amplify-and-forward (AP-AF). The authors also consider an algorithm where only one relay is selected in the transmission to maximize the mutual information. This is called selection amplify-and-forward (S-AF). S-AF selects the relay which results in the maximum mutual information between transmitter and receiver.Simulations of outage probability indicate that 5 dB of SNR can be saved for 3 relays by using S-AF instead of AP-AF. The authors in [9] derive symbol error probabilities for multiple paths of relays. 1. 3 OFDM in Cooperative Communications In this thesis, we continue to investigate cooperation by applying OFDM signals to cooperative relay netw orks. We consider a single path relay network and a multiple path relay network. Using the amplify-and-forward relay algorithm, we derive the input-output relations and the mutual informations of both networks. Using a power constraint at each relay, we consider two relay power allocation schemes.The ? rst is constant gain allocation, where the amplifying gain used in the amplify-and-forward algorithm is constant for all subcarriers. The second is equal power allocation, where each subcarrier transmits the same power. We simulate the mutual informations using these two relay power allocations. Using the decode-and-forward relay algorithm, we derive input-output relations for both 3 networks. We simulate bit error rates (BERs) and word error rates (WERs) for the two networks using both the amplify-and-forward and decode-and-forward relay algorithms. 1. 4Organization of Thesis The thesis is organized as follows. In Chapter 2, we consider the single path relay network in [3], [4]. In C hapter 3, we consider a modi? ed version of the multiple path relay network in [13] where the transmitter-receiver direct link is removed. Notice that these latter two relay con? gurations are series and parallel analogs of each other. As well, they do not involve a direct link between the transmitter and receiver. Finally, Chapter 4 concludes the thesis and provides future research directions. 4 CHAPTER II SINGLE PATH RELAY NETWORK 2. 1 2. . 1 Amplify-and-Forward System Model Figure 1 shows the single path relay network. In the ? gure, r0 is the transmitter, rm+1 is the receiver, and r1 , . . . , rm are m relay nodes connected in series forming a single path link between the transmitter and receiver. The relays perform amplify-and-forward (AF) relaying. We assume that OFDM with N subcarriers is used in the system. hk , . . . , hk (0) (m) (0) are the complex subchannel gains at the kth subcarrier in the link, for (m) k = 1 to N . nk , . . . , nk are the corresponding noises, which a re assumed to be mutually ndependent, zero-mean, circular symmetric complex Gaussians all with variance N0 B/N , where N0 is the power spectral density of the underlying continuous time noise process and B is the OFDM bandwidth of the system. Let pk = Ptot /N be the transmitter power on (l) the kth subcarrier, where Ptot is the net transmitter power. Let pk be the amplifying gain used in the amplify-and-forward algorithm at the lth relay, for l = 1 to m. The kth (0) receive symbol at rl is ampli? ed by pk before it is forwarded to the next node. (l) Let xk be the kth transmit symbol with zero mean and unit variance.Let yk be the kth receive symbol at the receiver. Using Figure 1, the input-output relation is (0) nk r1 nk hk (1) (m? 1) nk (m) rm+1 r0 hk (0) hk (m? 1) rm hk (m) Receiver Transmitter Figure 1: Single Path Relay Network 5 m yk = i=0 (i) hk (i) pk m xk + j=0 ? ? m (i) hk i=j+1 where we assume r i=q a(i) = 1 for q gt; r and any a(i) . We use this assumption throughout (i) (j) pk ? n k , ? (1) the rest of this paper. If we de? ne m hk = i=0 hk (i) pk , ? k = i=j+1 (i) (j) m hk (i) pk , (i) (2) ?k = and ?k (0)  ·  ·  · ? k (m) , nk = nk (0)  ·  ·  · nk (m) T , (3) wk = ? k nk , then (1) can be written as yk = hk xk + wk .Now, consider the variance of wk . Using (2), (3), and (4), we have Rw k w k ? = E [wk wk ] (4) (5) (6) (7) (8) (i) (i) bk p k ? , = E ? k nk nH ? H k k = ? k E nk nH ? H k k = N0 B N m j=0 ? m where E [ ·] is the expectation operator, ( ·)? is the complex conjugate operator for a scalar, ( ·)H is the Hermitian (complex transpose) operator for a vector or matrix, and bk = hk (i) (i) 2 ? i=j+1 ? (9) , for i = 0 to m. Rwk wk is positive for a nonzero N0 . We de? ne a transformed version of the system in (5) ? yk = hk xk + wk , ? ? (10) 6 ? where yk = yk / Rwk wk , hk = hk / Rwk wk , and wk = wk / Rwk wk .The variances of wk ? ? ? and yk are ? E [wk wk ] = E ? = wk Rwk wk ? wk Rw k w k (11) (12) (13) Rw k w k Rw k w k = 1 and E [? k yk ] = E y ? hk xk + wk ? ? hk xk + wk ? ? (14) (15) ? ? = hk h? + 1 k = 1 Rw k w k m i=0 bk p k (i) (i) + 1, (16) ? ? respectively. The cross terms do not appear in (16) because hk , wk , and xk are mutually independent. Note that the transformed system has unit variance noise. 2. 1. 2 Mutual Information To derive the mutual information, note that the di? erential entropy of a circular symmetric complex Gaussian vector, v, with covariance matrix, K, is h (v) = log2 det (? eK) [2].When the circular symmetric complex Gaussian is a scalar, v, the di? erential entropy is 2 2 h (v) = log2 ? e? v , where ? v is the variance of v. Let Ik be the mutual information between the transmitter and receiver on the kth subcarrier Ik = h (? k ) ? h (wk ) y ? = log2 ? e = log2 1 Rwk wk 1 Rw k w k m i=0 m i=0 (17) bk p k bk p k (i) (i) (i) (i) +1 ? log2 (? e) (18) (19) +1 , where the ? rst equality comes from basic mutual information calculations [1]. The total mutual information betwe en the transmitter and receiver, I, is the sum of all Ik divided by N . That is, after substituting (9) into (19), we have I = 1 N NIk k=1 (20) 7 = 1 N N k=1 log2 ? 1 + SNR ? T ? ? bk (0) (i) (i) m i=1 bk pk (i) (i) m i=j+1 bk pk m j=0 , (21) where SNR = Ptot /N0 B. If we denote b(i) = for i = 0 to m and T b1 (i)  ·  ·  · bN (i) and p(i) = p1 (i)  ·  ·  · pN (i) T , (22) eN = 1  ·Ã‚ ·Ã‚ · 1 N ones , (23) then (21) can be written in matrix form. First, let m zsingle = b(0) ? ? i=1 b(i) ? p(i) where the ? and ? operators both represent element-wise matrix multiplication and the ? /? ? m j=0 ? m i=j+1 b(i) ? p(i) , (24) ?/ operator represents element-wise matrix division. Then, (21) in matrix form is I= 1 T e log2 eN + SNR zsingle , N N (25) here log2 ( ·) of a vector is the vector of the logarithms of the vector’s entries. 2. 1. 3 Relay Power Allocation We assume that the net transmit power at the transmitter and at each each relay is Ptot . At the transmit ter, we assume a uniform power distribution, that is, pk (0) = Ptot /N . To (l) derive the power constraint at each relay and thus, possible power allocations, consider vk , the kth transmit symbol of rl vk = (l) (l) pk ? ? l? 1 i=0 N hk (i) pk (l) 2 (i) l? 1 xk + j=0 ? ? l? 1 i=j+1 hk (i) (i) (j) pk ? n k ? . ? ? (26) The constraint is Ptot = k=1 N E ? vk . Thus, l? 1 j=0 (l) (0) P Ptot = pk ? k tot N k=1 l? 1 i=1 bk p k (i) (i) N0 B + N ? ? l? 1 i=j+1 (i) (i) bk pk (27) 8 or pk ? (0) bk N k=1 N (l) ? l? 1 i=1 (i) (i) bk p k Note that (28) is de? ned recursively. The power constraint for pk depends on pk , . . . , pk pk is the base case in the recursion, which follows from (28), when l = 1. (1) 1 l? 1 ? l? 1 (i) (i) b p = 1. + SNR j=0 i=j+1 k k (l) ? (28) (1) (l? 1) . (l) One power allocation at the lth relay is to set pk constant for all subcarriers. This results in moving pk in (28) out of the summation because it is no longer a function of k pk,ct = pct = (l) (l) (l) N SNRN k=1 ? We call this constant gain allocation (CT). Note that this power allocation does not require each relay to have any CSI (channel state information). The lth relay only has to multiply its entire OFDM receive symbol by a constant, pct , such that the total transmit power is (l) ?SNRb(0) k l? 1 i=1 (i) (i) bk pct l? 1 + j=0 ? ? l? 1 i=j+1 (i) (i) bk pct . (29) Ptot . We call constant gain capacity, Cct , as the mutual information in (25) resulting from this power allocation. A second power allocation is to choose pk such that every subcarrier transmits the same power at the lth relay.The transmit power on the kth subcarrier is the kth summand on the right hand side of (27). Since they are all equal to Ptot /N , we have Ptot (l) (0) P = pk,eq ? bk tot N N pk,eq = SNRbk (0) (l) (l) ? l? 1 i=1 (i) (i) bk pk,eq N0 B + N l? 1 j=0 ? ? l? 1 i=j+1 or (i) (i) bk pk,eq (30) SNR l? 1 i=1 bk pk,eq (i) (i) l? 1 + j=0 ? ? l? 1 i=j+1 We call this equal power allocation (EQ). Note that this power allocation does require each relay to have the CSI of its upstream channels. We call equal power capacity, Ceq , as the mutual information in (25) resulting from this power allocation. 2. 1. 4 Capacity Simulations k pk,eq ? (i) (i) ?. (31) We simulate Cct and Ceq assuming that all distances between any two adjacent transceiver nodes are the same. Therefore, all path loss e? ects are normalized to 0 dB. Shadowing 9 between nodes is assumed to be log-normally distributed. That is, the received power gain due to shadowing in dB is a zero-mean Gaussian with variance of 8 dB, which is typical for cellular land mobile applications [12]. We model frequency selective fading e? ects as Typical Urban (TU) channels and Hilly Terrain (HT) channels [12]. We use an OFDM bandwidth of 800 kHz divided into N = 128 equal blocks.Maintaining OFDM orthogonality, this translates into an OFDM symbol period of Ts = 160  µs. Results are shown in Figures 2 and 3. The plots exhibit the familiar monot onically increasing shape for mutual information in the case of direct transmission between a transmitter and receiver. This is expected if we look at the mutual information in (25). We can think of this con? guration as still being direct transmission where the channel is the single path relay network, characterized by zsingle . Note that zsingle also determines the power allocations in the relays.In other words, (25) is a system level representation of the mutual information. As we increase the distance between the transmitter and receiver (and thus, add more relays), more noise and channel distortion enter the system. Consequently, the mutual information decreases. Equal power allocation results in a slightly higher mutual information than that of constant gain allocation. TU channels and HT channels give very similar results. 2. 2 2. 2. 1 Decode-and-Forward System Model In decode-and-forward (DF), each relay fully recovers the information bits (with possible errors) after receiv ing an OFDM symbol.It then converts the information bits back into an OFDM symbol and then transmits it. The transmitter and all the relays transmit with the same uniform power distribution. That is, pk = pk = for k = 1 to N and for l = 1 to m. (l) (0) Let xk be the kth transmit symbol from the transmitter and xk be the kth transmit (m+1) be the symbol from the lth relay, all with with zero mean and unit variance. Let yk (0) (l) Ptot , N (32) 10 8 7 8 Cct Ceq 7 Cct Ceq Capacity (bits/s/Hz) 6 5 4 3 2 1 0 Capacity (bits/s/Hz) 0 3 6 9 12 15 18 21 24 6 5 4 3 2 1 0 0 3 6 9 12 15 18 21 24 SNR (dB) (a) m=1 8 7 8 SNR (dB) (b) m=2 Cct CeqCct Ceq 7 Capacity (bits/s/Hz) 6 5 4 3 2 1 0 Capacity (bits/s/Hz) 0 3 6 9 12 15 18 21 24 6 5 4 3 2 1 0 0 3 6 9 12 15 18 21 24 SNR (dB) (c) m=3 SNR (dB) (d) m=4 Figure 2: Capacity in a single path relay network with TU channels using AF. N = 128, m = 1, 2, 3, and 4. 11 8 7 8 Cct Ceq 7 Cct Ceq Capacity (bits/s/Hz) 6 5 4 3 2 1 0 Capacity (bits/s/Hz) 0 3 6 9 12 15 18 21 24 6 5 4 3 2 1 0 0 3 6 9 12 15 18 21 24 SNR (dB) (a) m=1 8 7 8 SNR (dB) (b) m=2 Cct Ceq Cct Ceq 7 Capacity (bits/s/Hz) 6 5 4 3 2 1 0 Capacity (bits/s/Hz) 0 3 6 9 12 15 18 21 24 6 5 4 3 2 1 0 0 3 6 9 12 15 18 21 24 SNR (dB) (c) m=3 SNR (dB) (d) m=4Figure 3: Capacity in a single path relay network with HT channels using AF. N = 128, m = 1, 2, 3, and 4. 12 output 1 input output 2 output 3 Figure 4: Convolutional encoder. kth receive symbol at the receiver and yk be the kth receive symbol at the lth relay. Using (l) Figure 1, the input-ouput relation at the lth relay is yk = hk (l) (l? 1) Ptot (l? 1) (l? 1) + nk . x N k (33) The input-output relation at the receiver is yk (m+1) = hk (m) Ptot (m) (m) + nk . x N k (34) 2. 3 BER and WER Simulations We simulate bit error rates (BERs) and word error rates (WERs) for both the amplify-andforward and decode-and-forward cases.At the transmitter (and at the transmitter structure of a relay using decode-and-forward), each information word contains 83 bits. Using the convolutional encoder shown in Figure 4, the information word is encoded into a 255 bit codeword. A zero bit is padded at the end to make 256 bits. The bits are then interleaved and modulated onto N = 128 QPSK (quadrature phase shift keying) subcarriers to form one OFDM symbol. At the receiver (and at the receiver structure of a relay using decodeand-forward), the codeword is recovered (with possible errors) using a matched ? lter and 13 deinterleaving.A Viterbi decoder is used to decode the codeword. Both hard decisions and soft decisions are used. We assume that all distances between any two adjacent transceiver nodes are the same. Therefore, all path loss e? ects are normalized to 0 dB. Shadowing is assumed to be lognormally distributed. That is, the received power gain due to shadowing in dB is a zero-mean Gaussian with variance of 8 dB, which is typical for cellular land mobile applications [12]. We model frequency selective fading as Typical Urban (TU) channels and Hilly Terrain (HT) channels [12]. We use an OFDM bandwidth of 800 kHz divided into N = 128 equal blocks.Maintaining OFDM orthogonality, this translates into an OFDM symbol period of Ts = 160  µs. 2. 3. 1 Amplify-and-Forward The BER versus SNR and WER versus SNR plots for a single path relay network with TU channels using amplify-and-forward are shown in Figures 5 and 6, respectively. The corresponding plots for HT channels are shown in Figures 7 and 8, respectively. As expected, soft decisions in Viterbi decoding give better performance than hard decisions. In particular, there is up to 4 dB of SNR gain for the constant gain allocation and m = 1 case, as shown in Figures 5(a), 6(a), 7(a), and 8(a).In general, using hard decisions with constant gain allocation results in the worst performance. Soft decisions with equal power allocation gives the best performance, except for the m = 1 case, where soft decisions with constant gain allocation is slightly better. As w e increase the distance between the transmitter and receiver (and thus, add more relays), more noise and channel distortion enter the system. Consequently, the error rate (BER and WER) performance becomes worse and as a result, all four curves are very close together at low to medium SNR values. TU channels and HT channels give very similar results. . 3. 2 Decode-and-Forward The BER versus SNR and WER versus SNR plots for a single path relay network with TU channels using decode-and-forward are shown in Figures 9 and 10, respectively. The 14 10 0 10 0 10 ?1 10 ?1 BER 10 ?2 BER hard, constant gain allocation hard, equal power allocation soft, constant gain allocation soft, equal power allocation 0 3 6 9 12 15 18 21 24 10 ?2 10 ?3 10 ?3 10 ?4 10 ?4 hard, constant gain allocation hard, equal power allocation soft, constant gain allocation soft, equal power allocation 0 3 6 9 12 15 18 21 24 SNR (dB) (a) m=1 10 0 SNR (dB) (b) m=2 10 0 10 ?1 10 ?1 BER 10 ?2 BER ard, constant gain allocati on hard, equal power allocation soft, constant gain allocation soft, equal power allocation 0 3 6 9 12 15 18 21 24 10 ?2 10 ?3 10 ?3 10 ?4 10 ?4 hard, constant gain allocation hard, equal power allocation soft, constant gain allocation soft, equal power allocation 0 3 6 9 12 15 18 21 24 SNR (dB) (c) m=3 SNR (dB) (d) m=4 Figure 5: BER in a single path relay network with TU channels using AF. N = 128, m = 1, 2, 3, and 4. 15 10 0 10 0 WER 10 ?1 WER hard, constant gain allocation hard, equal power allocation soft, constant gain allocation soft, equal power allocation 0 3 6 9 12 15 18 21 24 10 1 10 ?2 10 ?2 hard, constant gain allocation hard, equal power allocation soft, constant gain allocation soft, equal power allocation 0 3 6 9 12 15 18 21 24 SNR (dB) (a) m=1 10 0 SNR (dB) (b) m=2 10 0 WER 10 ?1 WER hard, constant gain allocation hard, equal power allocation soft, constant gain allocation soft, equal power allocation 0 3 6 9 12 15 18 21 24 10 ?1 10 ?2 10 ?2 hard, constant gain alloc ation hard, equal power allocation soft, constant gain allocation soft, equal power allocation 0 3 6 9 12 15 18 21 24 SNR (dB) (c) m=3 SNR (dB) (d) m=4 Figure 6: WER in a single path relay network with TU channels using AF.N = 128, m = 1, 2, 3, and 4. 16 10 0 10 0 10 ?1 10 ?1 BER 10 ?2 BER hard, constant gain allocation hard, equal power allocation soft, constant gain allocation soft, equal power allocation 0 3 6 9 12 15 18 21 24 10 ?2 10 ?3 10 ?3 10 ?4 10 ?4 hard, constant gain allocation hard, equal power allocation soft, constant gain allocation soft, equal power allocation 0 3 6 9 12 15 18 21 24 SNR (dB) (a) m=1 10 0 SNR (dB) (b) m=2 10 0 10 ?1 10 ?1 BER 10 ?2 BER hard, constant gain allocation hard, equal power allocation soft, constant gain allocation soft, equal power allocation 0 3 6 9 12 15 18 21 24 10 ?2 10 ?3 10 ?3 10 4 10 ?4 hard, constant gain allocation hard, equal power allocation soft, constant gain allocation soft, equal power allocation 0 3 6 9 12 15 18 21 24 SNR ( dB) (c) m=3 SNR (dB) (d) m=4 Figure 7: BER in a single path relay network with HT channels using AF. N = 128, m = 1, 2, 3, and 4. 17 10 0 10 0 WER 10 ?1 WER hard, constant gain allocation hard, equal power allocation soft, constant gain allocation soft, equal power allocation 0 3 6 9 12 15 18 21 24 10 ?1 10 ?2 10 ?2 hard, constant gain allocation hard, equal power allocation soft, constant gain allocation soft, equal power allocation 0 3 6 9 12 15 18 21 24SNR (dB) (a) m=1 10 0 SNR (dB) (b) m=2 10 0 WER 10 ?1 WER hard, constant gain allocation hard, equal power allocation soft, constant gain allocation soft, equal power allocation 0 3 6 9 12 15 18 21 24 10 ?1 10 ?2 10 ?2 hard, constant gain allocation hard, equal power allocation soft, constant gain allocation soft, equal power allocation 0 3 6 9 12 15 18 21 24 SNR (dB) (c) m=3 SNR (dB) (d) m=4 Figure 8: WER in a single path relay network with HT channels using AF. N = 128, m = 1, 2, 3, and 4. 18 10 0 10 0 hard soft ?1 ? 1 hard soft 10 10 BER 10 ?2 BER 0 3 6 9 12 15 18 21 24 10 ?2 10 ?3 0 ?3 10 ?4 10 ?4 0 3 6 9 12 15 18 21 24 SNR (dB) (a) m=1 10 0 SNR (dB) (b) m=2 10 0 hard soft ?1 ? 1 hard soft 10 10 BER 10 ?2 BER 0 3 6 9 12 15 18 21 24 10 ?2 10 ?3 10 ?3 10 ?4 10 ?4 0 3 6 9 12 15 18 21 24 SNR (dB) (c) m=3 SNR (dB) (d) m=4 Figure 9: BER in a single path relay network with TU channels using DF. N = 128, m = 1, 2, 3, and 4. corresponding plots for HT channels are shown in Figures 11 and 12, respectively. As expected, soft decisions in Viterbi decoding give better performance than hard decisions. In particular, there is up to 5 dB of SNR gain, as shown in the plots.As we increase the distance between the transmitter and receiver (and thus, add more relays), more noise and channel distortion enter the system. However, the error rate (BER and WER) performance su? ers only slightly as m increases. TU channels and HT channels give very similar results. 2. 3. 3 Comparison The BER versus SNR and WER versus SNR plots for a single path relay network with TU channels using amplify-and-forward and decode-and-forward are shown in Figures 13 and 19 10 0 10 0 hard soft hard soft WER 10 ?1 WER 0 3 6 9 12 15 18 21 24 10 ?1 10 ?2 10 ?2

Describing Arizona SB1070(2010) Base on Political Conservatives View Essay

Describing Arizona SB1070(2010) Base on Political Conservatives View - Essay Example Liberal Beliefs. n.d.). Based on many debatable facts, the conservatives hugely support SB 1070 and describe it as positive step towards the betterment of the sate. The Fountain Hills State Representative, John Kavanagh is a strong advocate of Arizona SB 1070 and explains that the illegal immigrants are a significant problem. With considerable numbers of illegal immigrants within a population of 6 million in Arizona, we also look at the children eligible for availing government services (e.g. education). Since they were born here and are more deserving for these services, it becomes increasingly assuring that illegal immigrants should be driven out (Murphy 2012). Conservative Southern part of Tucson and Cochise County Representative, Ted Vogt has also described Arizona SB 1070 as being positive step since he believes reduced spending from the Government towards illegal immigrants is really important for the economy and the SB 1070 advocates this. Citing an official Government website, he had stated that the illegal immigration has costed to be around 900 million to 2 billion. The issue of illegal immigrants sweeping majority of the workforce also sparked some reservations which led to Arizona SB 1070 being supported. Russell Pearce’s support for SB 1070 is reflected when he stated that he believed that the illegal immigrants were reducing job opportunities for legal immigrants (Murphy 2012). The conservatives are also speaking in the favour of Arizona SB 1070 because; they believe that the crime is more rampant amongst the illegal immigrants. Representative Kavanagh made substantial claims using ‘Center for Immigration Studies report’ that, 8.9% of the population constitutes of illegal immigrants and are held responsible for 21.8% of the crime taking place in Maricopa city. Based on his experience doing an internship at US attorney

Co-Integration, Causality and Export-Led Growth in Portugal Article

Co-Integration, Causality and Export-Led Growth in Portugal - Article Example In the current study firstly, the Augmented Dicky Fuller (ADF) test is used for finding the order of integration between the two data series. Secondly, the Johansen maximum likelihood estimates are used for testing co-integration. Thirdly, the standard Granger-type test is adapted by using lag residual of the co-integrating regression model. Lag length for Granger causality test is determined by minimizing the Akaike’s Final Prediction Error (FPE). The data used in this study comprise annual secondary data of GDP and Exports values in Portugal between 1835 to1985 time period. The base year has been selected since 1914 for calculating the real prices. Statistical estimates of ADF test showed that log GDP and log Exports are 1(1) while the first difference of the level variables is 1(0). The trace statistics of the Johansen maximum likelihood is used to conclude that real GDP and real Exports values of Portugal are co-integrated and causally related. Four lags of the dependent variable are used in this model. Based on FPE criteria Granger causality test structure is determined as m=3, n=2, q=3, and r=4. Accordingly, the Wald test statistics of the Granger causality test rejected the null hypothesis in favor of reverse causality. Thus economic growth has caused export growth in Portugal during 1835 to1985 time period. The first section of the paper describes the concept of autocorrelation in relation to conventional research studies of applied economics. Autocorrelation or serial correlation is a common condition found in time series data. In OLS estimation residual is assumed to be independently distributed and does not contain any long run correlations. Thus in the presence of autocorrelation OLS estimates are not associated with minimum variance. Nevertheless, autocorrelation is not considered as a fatal statistical issue in econometrics analyses.  

Research paper Example | Topics and Well Written Essays - 1000 words - 28

Research Paper Example Many societies around the world suffer from poverty as a result of poor methods of sustainable development in the past(DeNavas-Walt and Proctor, 11). Poverty in various societies around the world is rooted from cultural and historical events. For instance, Poverty in America is portrayed by economic inflation created in the transition from the period after the American Revolution which was inspired by rebuilding strategies as the nation had undergone through a massive loss of lives and property worth billions of dollars. This document looks at the difference and similarities depicted in the transition with a comparison to Orwell’s concept of poverty as written in â€Å"Down and Out in Paris and London.† Orwell’s â€Å"Down and Out in Paris and London,† is a reflection of the current poverty state in some parts of the United States as it consists of similar events which link the 20th and 21st century. Down and Out in Paris and London,† is George Orwell’s story about the poverty state of immigrants living in Paris and London. In the story, the narrator tells the challenges that befall foreigners when in search for employment in a foreign land. He acquired his first job as a dishwasher in one of the hotels in Paris where employees who were mostly foreigners worked for twelve hours each day of the week with little pay. This made him live in a small and inveterately dirty room as there were no maids to clean the room since they were extremely cheap. The narrator’s place of residence depicted poverty in the immigrant society as most of his neighbours were foreigners from different countries in Europe with few coming from other continents around the world. The narrator describes the condition of the room in which he lived while in Paris saying, â€Å"The walls were as thin as matchwood, and to hide the cracks they had been covered with layer after layer of pink pap er, which had come loose and housed

Strategic Human Resources Planning in Healthcare

Strategic Human Resources Planning in Healthcare Strategic Human Resources Planning Executive summary A family group of companies dealing in pharmaceuticals has been in operation for decades distributing medical supplies such as syringes and bandages to different hospitals in their region. The company has established a reputation for itself, owing to the quality products and reliable services it offers the local hospitals. The companys success over the years can be attributed to its dedicated team of employees that has established a family like environment for its staff ensuring prolonged retention of its employees. The company also attributes its success to a dedicated customer satisfaction policy, which went to great lengths to ensure the needs of their customers are satisfied. The companys experience has grown over the years and with it, there has been a development in growth of their business network, whereby, the company supplies its products to hundreds of hospitals across Canada that has seen it open branches in different locations across the country. Background of Management/ Problem Statement Over the years, the business has been under the stewardship of the founders, who are mainly members of the same family. Being a small company only serving local hospitals, the company has experienced nothing but success among its workforce. However, with the expansion of company and the ever-changing technologies in medical field continues creating need for change not only in the products the company supplies but also in staff and management approaches. These changes have led the company to promote some of their existing staff or hire new ones to meet the demands in the changing market. Nonetheless, the companys human resources department is clouded with issues as the role of the department has grown to more than an amateur department for a small company. The troubled HR department is now experiencing staff departures and falling earnings. As such, the company needs to establish a human resource strategy to help create a balance between the employee and employer needs ensuring sustai nability of the business in the end. Project Stakeholders Roles and Responsibilities Managing Director Bill seats at the top of the company management chain, he owns the company and thus, all decisions that are made for the organization will need his blessing before they can be put into play. Project Directors These different directors within the company plan direct and oversee different projects ensuring the deliverables are reached as defined in the project goals. The directors also maintain accountability for the management of the company resources assigned to the project. Quality Managers They manage products and the process quality activities of the different project and offer an insight of the project health by offering a review of the process, product activities, and the required standards. Therefore, quality managers are vital to the human resources department especially towards activities of training needs analysis, training, hiring of skilled staff. Employees Employees are an important part of implementing change within an organization, since the changes to be implemented will mainly affect them directly. Therefore, as part of creating a strategic human resource plan, it will be important to seek what changes the employees would like to see, be it technological, managerial, work schedules, and other workplace related issues influencing productivity. Operations Lead These are the individuals mandated with the overseeing of different operations of a new system, as well as monitoring and managing operations and resolutions of operations support issues. The operations leads are an important part of change within the organization, as they will play a key role towards implementing new management software that is needed for the human resource department. Approaches to Solving the Human Resources Issues Labor Relations According to Noe et al (2006), worker labor relations are dedicated to endorsing operative fairness, and specialized associations between a corporation and its personnel. Through effective labor relations, the company will be able to solve various problems it is faced with including among others establishing awell-organizedfabrication of goods. At the same time, the labor relations will allow a determination of satisfactory terms and circumstances of service considering both the good of the proprietor, personnel, and as well as the society via agreements reached through negations. Thus, strategic plan to use labor relations will establish stable and harmonious relations between the Family Company and its employees, and between them and their society. Labor relations also go a long way towards establishing mechanisms of communication within the organization. In addition, the practice establishes channels of consultation and collaboration to determine workplace matters at the industrial level through agreed harmony. The family company is faced with numerous disputes between its management and the employees, labor relations can be used to mitigate these disputes to aid in the settlement and future avoidance through negotiations and dispute settlement mechanisms. The process would go a long way towards the provision of social protection where it might be needed especially in areas of social security, child labor, safety, and health (Noe et al, 2006). Talent Management and Staff Development The organization has been in constant need of a human resource assistant to deal with growing workforce and ensure the needs and work schedules of the employees are in order. This objective could be attained through talent management in the company. According to McCauley and Wakefield (2006), capacity supervision is assignment critical procedure that sees to it that an organization has the quality and amount of individuals in place to meet their existing and impending business urgencies. In line with this staff development process, the company will cover all the key aspects of the employees life covering the selection process, the growth, succession, and the management of performances. The Family Medical Group Company can thus have talent management as part of their human resource strategic plan ensuring the human resource department always has a clear understanding of the organizations prevailing and future operational strategies. The organization will also from time to time be able to identify any gaps arising between the current talent and that required to attain business success. In addition, running a talent management plan will ensure the firm is accurate in hiring and promotions decisions it undertakes. Finally, the human resources team will easily  connect individual goals to corporate goals providing organizational expectations and offer feedback to aid manage performance (McCauley and Wakefield, 2006). Work Design/ Classification Organizations can employ the high relationship prevailing between employee satisfaction with the work environment, which includes the rules, technology in use, and the office design to attain organizational success. Where new employees join the company, design can be employed to ease transition to the new work environment for the new employee and enhance productivity. Under the work design, the firm should get rid of disruptions and offer its employees a comfortable environment that support their needs in the process transforming attitudes about work and increase output and efficiency (Enz and Siguaw, 2000). The companys revenues have been decreasing, for the human resources department to save this situation, it has to maximize the intellectual capital and to do this, it has to establish effective work processes, and through an environment, that supports it. According to do Enz and Siguaw(2000), where an efficient work environment has been created and the staffs are proud of it, then consequently job performances improve. In addition, work environments that are known to adopt work designs that are supportive of the way people need to work, it strengthens morale and promotes a positive attitude about their duties and enhances productivity. Performance Management This is a procedure of fashioning workplace setting where individuals can accomplish tasks to the best of their capacities. Thus, performance management commences when the job is defined as needed. The process is a collaboration between the employer and employees making major interaction opportunity with the employees a learning occasion. Developing a performance management plan is vital to the human resources department of the firm since it contributes establishing an employee recruitment plan, allowing the firm to recruit potential employees in the process. Implementing a performance management plan will bring various advantages including creating job specification and it aligns the firms strategic organization and culture, offers an accurate picture of the different employees performances. The process will also make for collaborative process geared towards setting goals and review performances following a two-way communication channel between the firm and its staff. The plan will monitor and measure results and behaviors, including issuing feedback on the different tasks carried out with the firm. Where there are, training needs, the plan creates training and development opportunities, and most importantly, it identifies areas of poor performance and establishes plans to improve these areas (Den Hartog et al, 2004). Organization Development According to Cummings and Worley (2014), where organizational development is part of a strategic human resources the organization will benefit by further strengthening its leadership capabilities of the firms supervisory personnel. Organization Development will increase the organizations capacity to a well manage assortment and identify natural differences that exist at the workstation, the process will go a long way towards employees skills, create accountability, and offer resources that will enable the organization create long-term sustainable change. The process of organizational development will help reduce the staff turnover rate, work on the low staff morale reported by the managers, fight the prevailing inability to effectively communicate throughout the organization, and work on the disconnection between the supervision and the staff. In addition, organization development will play a part to train employees for career development, providing flexible learning options by encouraging employees to engage self-learning and engage in development activities,  and build trust between the staff and the leadership in the organization. The plan will also help the human resources department in matching the various available learning options to different learning styles (Cummings and Worley, 2014). Training Needs Analysis According to Brown (2002), operative training needs analysis is predominantly important in the modern day changing work environment as new machineries and elastic working performance are prevalent, that correspond to changes in the skills and abilities. Training needs analysis will enable the firm to station funds into the zones where they will underwrite to the expansion and enhancing drive among the employees. As well, the employees will need to be trained to bridge the existing skill gap and training needs analysis is important for an effective training program. Through training needs analysis, the organization will be able to channel its available resources to areas where they will be able to contribute to employee development in the process enhancing productivity at the workplace. Ensuring training needs analysis is part of the strategic human resource plan will ensure the organization priorities are put into consideration and economies of scale are attained. Additionally, the firm will have an opportunity to consider its future needs, and develop monitoring techniques to use within the organization. The investigation will help the organization to investigate unexpected problems and indicate where gaps exist within the organization. This part of the plan will aid in establishing the level of need, and come up with a plan to mitigate the need by considering the kind of training that will be most appropriate (Brown, 2002). Staff Acquisition The top management in the firm will negotiate with functional and department managers to identify and assign resources in line with the firms project organization structure. In addition, the plan will identify external sources and mechanisms to hire new project sources, and allow an approval of the project works. The upgrade of the management system will include alliancing with the vendor, in corroboration with the human resource management team. Nonetheless, the vendor will need to transfer his expertise to the staff to ensure the transition of the project transpires (Brown, 2002). Conclusion The strategic human resource plan will go a long way in helping the Family Medical Group of Companies archive its goals. The process will act as the link between the management of the organization and the overall strategic plan of the plan. The strategic plan will aid the organization in meeting their mission, help the organization assess the current human resource capacities, foresee the requirement of the organization, analyze gaps, and come up with strategies that support organization strategies. References Brown, J. (2002). Training needs assessment: A must for developing an effective training program. Public personnel management, 31(4), 569-578. Cummings, T. G., Worley, C. G. (2014). Organization development and change. Cengage learning. Den Hartog, D. N., Boselie, P., Paauwe, J. (2004). Performance management: A model and research agenda. Applied psychology, 53(4), 556-569. Enz, C. A., Siguaw, J. A. (2000). Best practices in human resources. The Cornell Hotel and Restaurant Administration Quarterly, 41(1), 48-61. McCauley, C., Wakefield, M. (2006).Talent management in the 21st century: Help your company find, develop, and keep its strongest workers. The Journal for Quality and Participation, 29(4), 4. Noe, R. A., Hollenbeck, J. R., Gerhart, B., Wright, P. M. (2006).Human resource management: Gaining a competitive advantage.

Philosophy Of Literacy Instruction Essay -- Teaching Education School

Literacy Defined Literacy embraces reading, writing, listening, and speaking. Integrating all of these into a literacy program is key. Teachers must provide endless and ongoing opportunities for their student to read, write, listen, and speak. There are many components that make up literacy. In order to effectively teach students these components the teacher must model the concept for the students. As teachers, we can't expect or assume that the student already knows what we expect of them. Modeling gives students a basis of what to go by. Modeling is the first and most important step in order for the students to gain mastery of a concept. A teacher must also undergo guided practice with the students. A teacher should always provide as much guided practice that is needed. Students should never move on to independent practice until it is evident that they are ready. For example, I was teaching a guided reading lesson in my EDU 218 classroom, in which my peers were posing as students. The lesson involved the students to complete a story map on a book that they read. Although I knew that the students would be slightly familiar with a story map I still modeled the use of it for them. I modeled the use of the story map based on a book that I knew the students were familiar with. So when the students set out to complete the story map on their own they could recall and look back to the story map that I had modeled for them. It is also important to note that not all students grasp the material at the same time. One student could be ready for independent practice, as another may still need a vast amount of guided practice. There is no need to caution if students are not at the same level, unless of course if there is a real developmental delay. Literature is a key component when speaking of literacy. Teachers need to provide students with endless amounts of practice experiences in reading to build their fluency rate. This should be done with different genres of texts and different levels. Reading a wide variety of literature help children develop rich vocabularies. Phonemic Awareness is very important part of literacy. Phonemic awareness includes sounds of a word, the breakdown of words into sounds. It includes rhyming and alliteration, isolation, counting words in sentences, syllables and phonemes, blending words, segmenting, and manipulating. Pho... ...on my students work so that they know how they are progressing. I will always be sure to hit my instructional focus on the children?s strengths before working on an area of development with the children. I will teach to the objectives and I will teach to the standards. I will make sure that my lessons are hitting on as many standards as possible. Working With Children with Special Needs In my classroom I will make sure that the children with special needs are benefiting from instruction. I will pair this student up with someone who is capable of helping. The student will be getting my instruction as well as help from one of their peers. I will be aware that this student is a learner with special needs and I will teach this student at a level in which he/she is comfortable. I will make sure I am aware of everything that I can about this student?s special needs. I will be in a tight contact with the student and his/her parent/guardian so I can be aware that they are working with him/her at home. If this isn?t the case then I will pair this student up with another student after school, with myself, or with someone else that would be willing to give this student extra time.