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A Link Level Simulator of the cdma2000 Reverse Link Physical Layer

A Link Level Simulator of the cdma2000 Reverse Link Physical Layer

Our main objective in this section is to evaluate the effect of the receiver design and diversity on the performance of cdma2000 reverse-link physical layer. A detailed description of the rake receiver design, including an ideal rake receiver, has been given in Sec. 5. The IMT-2000 Vehicular Model-A, shown in Fig. 5, was used as the propagation channel model together with AWGN to simulate thermal noise plus inter-cell and intra-cell interference. In the SPW simulation model, each chip is over-sampled by a factor of 8. As a low-pass filter at the transmitter and receiver, the square-root raised-cosine (SRRC) filter with roll-off factor of 0.22 was employed. In our model, it is assumed that each finger in the rake receiv- er has perfect synchronization with the corresponding path. The carrier frequency was set at 1.9 GHz. For each measurement, the mean output power on each channel was calculated from the reverse link model in accordance with the link budget (see Sec. 6). All meas- urements carried out in this paper are based on a single user transmission using Radio Configurations 5 and 6. In addition, the initial values and relative gain adjust- ments in the link budget were set to zero (see Sec. 6). As discussed earlier, the mean pilot channel power was first calculated by the SPW model's link budget by specifying the Received Power Spectral Density (PSD) at the mobile station's antenna connector.

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A Combined Antenna Arrays and Reverse Link Synchronous DS CDMA System over Frequency Selective Fading Channels with Power Control Error

A Combined Antenna Arrays and Reverse Link Synchronous DS CDMA System over Frequency Selective Fading Channels with Power Control Error

For a terrestrial mobile system, reverse-link synchronous transmission technique (RLSTT) has been proposed to re- duce interchannel interference over a reverse link [7]. In the RLSTT, the synchronous transmission in the reverse link can be achieved by adaptively controlling the transmission time in each mobile station (MS). In a similar way to the closed- loop power control technique, the BS computes the time dif- ference between the reference time generated in the BS and the arrival time of the dominant signal transmitted from each MS, and then transmits timing control bits, which order MSs to “advance” or “delay” their transmission times. The consid- ered DS-CDMA system uses orthogonal reverse-link spread- ing sequences and the timing control algorithm that allows the main paths to be synchronized.

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Reverse Link Outage Probabilities of Multicarrier CDMA Systems with Beamforming in the Presence of Carrier Frequency Offset

Reverse Link Outage Probabilities of Multicarrier CDMA Systems with Beamforming in the Presence of Carrier Frequency Offset

The outage probability of reverse link MC-CDMA systems with beamforming in the presence of CFO over Nakagami fading channels is evaluated in this paper. A simplified beam- forming model is utilized to reduce the complexity of the analysis. A closed-form expression of the outage probabil- ity is obtained to examine the effect of CFO and beamform- ing. First, the outage probability is evaluated when perfect beamforming is assumed. It can be concluded that the outage probability improves significantly as the number of antenna elements increases; second, the outage probability is investi- gated when different types of beamforming impairments are present in the system. It is seen that small DOA estimation er- rors and angle spreads have only a slight impact on the outage probability of the system; however, as those impairments be- come large, the outage probability deteriorates significantly. Also it is observed that the outage probability changes very slightly when there is mutual coupling in the antenna array. ACKNOWLEDGMENT

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Performance of Power Control Algorithm for DSCDMA on Reverse Link

Performance of Power Control Algorithm for DSCDMA on Reverse Link

Considering the 2D urban model for computing reverse link (path between a mobile set and base station) is shown in Fig 1. This shows that diffraction and reflection of power signal from mobile user and base station. This cause the loss in power of the signal due diffraction and reflections provide obstacle such as building, trees mountains etc. whereas these signal remains in the environment until its power of the signal fall below the threshold level. Block diagram of reverse link is shown in Fig. 2(a). The USPS simulation software is used, in which it is considered to as physical environment of mobile user such that signal data radiated from mobile system reaches to base station as well as diffuse in all the directions. This software also stores all environment information angles of the path (reverse link or forward link) and transmitting and receiving power. Block diagram of reverse link and forward link are shown in Fig 2.

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Performance of Reverse Link Synchronous DS CDMA System on a Frequency Selective Multipath Fading Channel with Imperfect Power Control

Performance of Reverse Link Synchronous DS CDMA System on a Frequency Selective Multipath Fading Channel with Imperfect Power Control

Direct-sequence code-division multiple-access (DS-CDMA) has been considered as the most promising multiple-access scheme for the next generation mobile communications, be- cause of its high flexibility in o ff ering various services with variety of rates and its possibility of achieving greater capac- ity [1, 2]. The capacity of DS-CDMA system is mainly limited by multiple-access interference (MAI), and thus techniques to reduce the MAI, such as multiuser detection or interfer- ence cancellation, are currently of great interest [3, 4, 5]. In particular, techniques for reverse links have attracted much attention, as the capacity of a reverse voice cellular network link is smaller than that of the forward link. One reason for this is that the code orthogonality is not maintained, because in the reverse link the arrival times of signals from mobile stations (MSs) at a cell site (CS) are di ff erent, given the ran- dom geographical distribution of MSs within the cell sector.

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Analysis of a Combined Antenna Arrays and Reverse Link Synchronous DS CDMA System over Multipath Rician Fading Channels

Analysis of a Combined Antenna Arrays and Reverse Link Synchronous DS CDMA System over Multipath Rician Fading Channels

However, previous studies [8, 13] have assumed the pres- ence of Rayleigh fading and have neglected the performance benefit of having a specular component in Rician fading channel, which is often characterized in microcellular envi- ronments [14, 15]. Even if [16] presents the analysis of the scenario of a direct line-of-sight (LOS) path, it has not con- sidered the use of spatial processing at cell site (CS). There- fore this paper presents the BER analysis of AA receiver in reverse-link asynchronous multipath Rician channels, and analyzes the performance of an improved AA, in which RL- STT is incorporated to effectively make better an estima- tion of covariance matrices at a beamformer-RAKE receiver through the analysis of the scenario of a direct LOS path, which results in Rician multipath fading. While RLSTT is ef- fective in the first finger at the RAKE receiver in order to re- ject MAI, the beamformer estimates the desired user’s com- plex weights, enhancing its signal and reducing CCI from the other directions. In this work, we attempted to provide a comprehensive analysis of user capacity which reflects several important factors such as the ratios of the specular compo- nent power to the Rayleigh fading power, the shape of multi- path intensity profile (MIP), and the number of antennas.

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Traffic Modelling for Capacity Analysis of CDMA Networks using Gausian Approximation Method

Traffic Modelling for Capacity Analysis of CDMA Networks using Gausian Approximation Method

Cooper in his work [3]carried out analysis of cell interference in spread spectrum. An extension of this which includes the effects of shadowing and voice activity monitoring, is found in the work of Gilhousen. In the paper[4] by Fapojuwo in 1993, a computationally intensive procedure is presented for the evaluation of the teletraffic capacity of both forward and reverse links in a CDMA cellular system. Kim in 1993[5], did a very similar analysis with the exception that the fixing of the PLE at 4 leads to analytic expressions for the interference from the circular cells. This is extended to an analytic result for variance [6]. A standard hexagonal cellular layout is assumed with the propagation model in the paper[7] by Kohno et al in 1995, which includes lognormal shadowing taken to be independent on distinct paths .An extension of the reverse link analysis of the work by Gilhousen et al is

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Representative Delay Measurements (RDM): Facing the Challenge of Modern Networks

Representative Delay Measurements (RDM): Facing the Challenge of Modern Networks

Fig. 4 illustrates the impact of time-slotted randomness can- cellation and on-demand capacity allocation onto the repre- sentativity of reverse link measurement results. The pre- sented use case is equivalent to the one of round-trip mea- surements with a traditional ping utility and randomized start times, i.e., it matches the measurement methodology recommended by pre-RFC7312 IETF documents. The mea- surement setup is depicted in Figure 1, measuring HSPA uplink as forward link and HSPA downlink as reverse link. The 10 ms transmit time interval (TTI) used by the mea- sured public HSPA network for uplink and for downlink is identified for uplink by the time clustering in Figure 2. The HSPA downlink delay scatter diagram in Figure 4(a) and histogram in Figure 4(e) illustrate the negative effect of randomness cancellation on measurement sample represen- tativity. The artificial “layering”, corresponding to a multi- modal sample distribution document that decomposition of round-trip delay samples into OWD samples is not accept- able for representative delay measurements in time-slotted networks. After enabling the RDM artificial random server delay functionality, the downlink delay diagrams in Figure 4(b) and Figure 4(f) depict the ”true” downlink delay range. These diagrams are identical to the ones obtained when re- versing client and server position in the measurement setup in Figure 1 such that HSPA downlink is measured first as forward link.

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Linkage mechanics and power amplification of the mantis shrimp's strike

Linkage mechanics and power amplification of the mantis shrimp's strike

Fig.·9. The four-bar model predictions vary depending on relative link lengths and starting angles. The linkage mechanism is operational in two regions between input rotations of 0 and 360° (region from 0 to 180° shown; the range from 180–360° is the mirror image of 0 to 180° and is never used by mantis shrimp). The horizontal lines at output rotations of 0° and 180° indicate that a change in input rotation does not yield any output rotation (i.e. the linkage mechanism is non- operational). (A) An input rotation between 40° and 120° yields an output rotation depending on relative link lengths. Green traces show the predicted behavior based on the link lengths of a relaxed raptorial appendage (i.e. Link 4 extensor muscle is not contracted). Blue traces show the predicted behavior of the relaxed appendages if Link 4 is constrained to the average shortened length observed in video images. Red traces illustrate the range of behaviors given the range of link lengths measured in loaded appendages from video images. The thick black line provides the linkage model behavior given the average link lengths measured from the loaded images (red lines; also shown in Fig.·10). (B) The predicted model behavior of four individuals (each color represents a different individual) given measured inputs and link lengths from high-speed video sequences.

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GROUP OF RECURRENT NEURAL NETWORKS

GROUP OF RECURRENT NEURAL NETWORKS

ii SEAD (Secure Efficient Adhoc Distance Vector Routing Protocol): It is[39] based on DSDV routing protocol. This protocol is used to guard against Denial of Service by using one way hash functions. It provides limited CPU processing capability. Long lived routing loops can be reduced by using destination sequence numbers. These destination sequence numbers provide replay protection of routing update messages in SEAD. iii SAODV: It is an enhancement over AODV [1][40] routing protocol that utilizes security feature like integrity and authentication. It uses digital signature to authenticate non mutable field of messages and hash chains to secure hop count information. IPSec provides secure network transmission in MANET for data messages. And digital signature is used when a RREQ is sent between source node to destination node. Primarily, sender node signs the message and intermediate node verifies the signature before generating of reverse route to the host. And destination node signs the RREP to its private key.

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Reverse logistic for industrial building system construction project

Reverse logistic for industrial building system construction project

The RLRFE (reverse logistic recycling flow equilibrium) problem as a flow equilibrium problem from a system wide policy-making perspective, focusing particularly on equilibrium in situations in which market price and recycling channel flows are coupled interactions and input-output recycled material flows at each agent are not balanced. They propose a three-loop nested diagonalization method in which asymmetric link interactions are gradually relaxed to achieve the equilibrium solution (Kara et al., 2007)

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On the Link Floer Homology of L space Link

On the Link Floer Homology of L space Link

Proof: First we compute the signature of b(q 0 k + 1, k). Since q 0 k+1 k = q 0 + 1 k , we can use Figure 5.2 to give a diagram D for b(qk − 1, k). Now we will use the Gordon-Litherland formula for knot signature(see [4]) on D. Since the surface given by a checkerboard coloring of D is orientable, the signature of the link is simply the signature of the Goeritz matrix for D (see the end of the first page in [4]). We denote by A n (p) the n × n matrix with A 11 = p, A ii = 2 when 2 ≤ i ≤ n, A ij = −1

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CISSP   Certified Information Systems Security Professional Study Guide, 4th Ed  pdf

CISSP Certified Information Systems Security Professional Study Guide, 4th Ed pdf

One very important security issue to recognize with WAP or with any security service pro- vided by a telco is that you are unlikely to obtain true end-to-end protection from a commu- nications service provider. The U.S. law known as the Communications Assistance for Law Enforcement Act (CALEA) mandates that all telcos regardless of the technologies involved must make it possible to wiretap voice and data communications when a search warrant is pre- sented. Thus, a telco cannot provide customers with end-to-end encryption. At some point along the communication path, the data must be returned to clear form before being resecured for the remainder of the journey to its destination. WAP complies with the CALEA restriction as follows: a secure link is established between the mobile device and the telco’s main server using WAP/WTLS. The data is converted into its clear form before being reencapsulated in SSL, TLS, IPSec, and so on, for its continued transmission to its intended destination. Knowing this, use telco services appropriately, and whenever possible, feed preencrypted data into the telco link rather than clear form data.

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Control of Multi-Link Robots with Link Flexibility

Control of Multi-Link Robots with Link Flexibility

The flexible robots are favoured in industries and in space applications due to their quick response, low energy consumption, lower overall mass and operation at high speeds compared to conventional industrial rigid link robots. These flexible linkrobots are inherently flexible and this effects the end-point positioning accuracy of the robot. It is important to model the link kinematics with precision which in turn simplifies the modeling of dynamics and control of flexible link robots. The main objective of this paper is to design two types of controllers (PD and PI) to reduce the error at the tip position of two link Revolute-Revolute type Manipulator and ensure that the end effector will follow the specified vertical path when the two links are flexible and the payload is equal to the links mass.

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ANALYSIS OF SPATIAL MECHANISM IN DYNAMIC EQUILIBRIUM CONDITION USING MATLAB

ANALYSIS OF SPATIAL MECHANISM IN DYNAMIC EQUILIBRIUM CONDITION USING MATLAB

The links are represented with bars or triangles. The one degree of freedom joints are represented with a cross circle. General analytical model and inertial properties of each moving link is represent in fig 3.The link 1 is connected to ground 0 at A and to link 2 at B, Fig. 1. The link 2 is connected to link 1 at B and to link 3 at B. Next, link 3 is connected to link 2 at B, link 0 at C, and link 4 at D. Link 3 is a ternary link because it is connected to three links. At B there is a joint between link 1 and link 2 and a joint between link 2 and link 3. Link 4 is connected to link 3 at D and to link 5 at D. The last link, 5, is connected to link 4 at D and to 0 at A. In this way the table in Fig. 1.12a is obtained. At A there is a multiple joint, two rotational joints, one joint between link 1 and link 0, and one joint between link 5 and link 0. The number of DOF for the mechanism is M = 3(5) −2(7)= 1. If M = 1, there is just one driver link. One can choose link 1 as the driver link of the mechanism. Once the driver link is taken away from the mechanism the remaining kinematic chain (links 2, 3, 4, 5) has the mobility equal to zero. The dyad is the simplest system group and has two links and three joints.

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The reverse DTML-conversion model with its mathematical formulas

The reverse DTML-conversion model with its mathematical formulas

The Reverse DTML-Conversion Model is a model that has been designed by the researcher to make the teaching of conversion in measurement very easy to tutors and meaningful to students. This employs the use of a straight line divided into equal sections/parts depending on the physical quantity of concern. The three fundamental/basic physical quantities which are used in this model are distance, time and mass. Conversion within quantities of same units and between quantities of different units is a thorny subject to students (Butterfield, Sutherland & Molyneux-Hodgson, 2000) and its treatment by tutors sometimes becomes very difficult such that tutors resort to handling the subject theoretically/abstractly. When this happens most students seemed not to comprehend the subject.

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Link Services or Link Agents?

Link Services or Link Agents?

When the link server incorporated links directly into the contents of each document, the links themselves took on an importance that was immediate as that of the document itself. This was one reason why it was necessary to use different colors and link styles to allow the user to distinguish links originally placed in the document by the author from links added by the link service. If the links are now being presented independently of the document and at some time after the document is delivered, link processing now takes the status of an advisory service which can add value to the user’s browsing process, but which is not confused with the original document contents. This is an advantage from the point of view of publishers’ copyright and licensing (no derivative works are created) but also with respect to the author’s moral rights to have a document displayed “without any amendment that impugns his or her integrity or reputation” [20]. The problem with link compilation is that the author’s moral right encompasses even the case of having their material linked to a document of which they disprove.

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A Survey on Multiword Smart Crawler for Effective Web Searching

A Survey on Multiword Smart Crawler for Effective Web Searching

It is difficult to search the deep web databases, because they are not registered with any search engines, are usually sparsely distributed, and keep constantly changing. To address this problem, we use generic crawlers and focused crawlers. Generic crawlers fetch all searchable forms and cannot focus on a specific topic. The link classifiers in these crawlers play a pivotal role in achieving higher crawling efficiency than the best-first crawler However, these link classifiers are used to predict the distance to the page containing searchable forms, which is difficult to estimate, especially for the delayed benefit links (links eventually lead to pages with forms). As a result, the crawler can be inefficiently led to pages without targeted forms.

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Eliminating  Leakage  in  Reverse  Fuzzy  Extractors

Eliminating Leakage in Reverse Fuzzy Extractors

Abstract—In recent years Physically Unclonable Functions (PUFs) have been proposed as a promising building block for key storage and device authentication. PUFs are physical systems and as such their responses are inherently noisy, precluding a straightforward derivation of cryptographic key material from raw PUF measurements. To overcome this drawback, Fuzzy Extractors are used to eliminate the noise and guarantee robust outputs. A special type are Reverse Fuzzy Extractors, shifting the computational load of error correction towards a computationally powerful verifier. However, the Reverse Fuzzy Extractor reveals error patterns to any eavesdropper, which may cause privacy issues (due to a systematic drift of the PUF responses, the error pattern is linkable to the identity) and even security problems (if the noise is data-dependent). In this work we investigate both these issues and propose modified protocols that eliminate the problems.

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Acute Reverse Remodelling After Transcatheter Aortic Valve Implantation: A Link Between Myocardial Fibrosis and Left Ventricular Mass Regression

Acute Reverse Remodelling After Transcatheter Aortic Valve Implantation: A Link Between Myocardial Fibrosis and Left Ventricular Mass Regression

Left ventricular (LV) hypertrophy is almost ubiquitous in severe aortic stenosis (AS), reflecting myocardial adaptation to chronic elevation of afterload, in an attempt to normalise wall stress[1, 2]. Surgical aortic valve replacement (SAVR) and trans-catheter aortic valve implantation (TAVI) result in significant LV mass regression at medium and long term follow up[3, 4], with TAVI having a superior mass reduction compared with SAVR at 6 months[3]. TAVI results in an immediate, greater improvement in aortic pressure gradient[5]. This early improvement may be responsible for the greater degree of mass regression seen at mid and long term, which remains important as LV mass regression is a positive prognostic indicator[6] and is associated with reduced hospitalisation[7]. The acute effects of the reduction of afterload on the LV afforded by TAVI have not been described using Cardiovascular Magnetic Resonance (CMR) imaging. Studies to date investigating early mass regression following TAVI have used echocardiographic evaluation[8] and hence are underpowered[9]. The relationship between baseline myocardial fibrosis and early LV reverse remodelling remains poorly understood[10]. CMR imaging allows accurate assessment of LV mass regression and myocardial fibrosis. This may allow us to predict which patients are most likely to derive an immediate benefit from TAVI.

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