Transfer Bandwidth Research Articles

PERANCANGAN DAN ANALISA JARINGAN KOMPUTER DENGAN MENGGUNAKAN TEKNOLOGI NIRKABEL BERBASIS WIFI PADA STMIK AMIKOM PURWOKERTO

The purpose of this research is to design a computer network-based wireless technolgy with Wi-Fi, especially to overcome problems that occur due to design of computer network are still based on cable technology that is still widely used and inefficient use of bandwidth for file transfer. The methods used include two main parts namely the design methods amd analytical methods. Design method is used to create a wireless network topology as well as making new applications for file transfer and analytical methods used to analyze system that are running. So that the results achieved is the design of a network that has high mobility and bandwidth savings. Conclusions obtained that by conversion system from Ethernet networks into wireless network to increase the number of clients that can access into the network and could increase employee mobility notebook users. In addition, the addition of a new file transfer application could reduce traffic to the Internet bandwidth usage. Keywords : wirelless LAN, access point, Wi-Fi topology, File Transfer.

An adjustable power management for optimal power saving in LTE terminal baseband modem

Long term evolution (LTE) of 3GPP provides high bandwidth for data transfer. In the viewpoint of the LTE terminal baseband modem chip, these high data rates require more complex logics and memories than previous baseband modem chips in preceding technologies such as Wideband Code Division Multiple Access (W-CDMA), High Speed Downlink Packet Access (HSDPA), and High Speed Packet Access (HSPA). It may exhaust user equipment (UE)'s battery power quickly. Thus, LTE provides an enhanced discontinuous reception (DRX) to extend the UE's battery lifetime. In this work, we propose an adjustable power management using a hierarchical cascaded power gating (HCPG) and a hierarchical multi-level clock gating (HMLCG) with special regard for DRX framework. The test results from the designed ASIC show that optimal power saving was achieved by using the proposed adjustable power management.

Dynamic Reconfiguration of Differential Pixel Output for CMOS Imager Dedicated to WDM-SDM Indoor Optical Wireless LAN

A dedicated complementary metal-oxide-semiconductor (CMOS) imager with parallel photoreceivers has been deployed for new indoor wireless local area network systems where images and communications are mixed to offer location awareness and an extended data transfer bandwidth with wavelength- and space-division multiplexing for the downlink and uplink, respectively. To realize data acquisition while capturing images, dynamic reconfiguration of differential pixel output with a small area overhead is proposed for suppressing signal contamination at the sensitive photoreceiver circuitry by common mode noise from the image readout digital circuitry. A prototype CMOS imager with 64 times 64 pixels and four parallel photoreceiver channels was fabricated in a standard 0.35-mum CMOS process, and concurrent scene image capturing and multipoint data acquisition at 10-Mb/s/channel were demonstrated. The measured signal-to-crosstalk ratio was around 18 dB.

Dynamic Control of Random Constant Spreading Worm using Depth Distribution Characteristics

Ever since the network-based malicious code commonly known as a `worm` surfaced in the early part of the 1980`s, its prevalence has grown more and more. The RCS (Random Constant Spreading) worm has become a dominant, malicious virus in recent computer networking circles. The worm retards the availability of an overall network by exhausting resources such as CPU capacity, network peripherals and transfer bandwidth, causing damage to an uninfected system as well as an infected system. The generation and spreading cycle of these worms progress rapidly. The existing studies to counter malicious code have studied the Microscopic Model for detecting worm generation based on some specific pattern or sign of attack, thus preventing its spread by countering the worm directly on detection. However, due to zero-day threat actualization, rapid spreading of the RCS worm and reduction of survival time, securing a security model to ensure the survivability of the network became an urgent problem that the existing solution-oriented security measures did not address. This paper analyzes the recently studied efficient dynamic network. Essentially, this paper suggests a model that dynamically controls the RCS worm using the characteristics of Power-Law and depth distribution of the delivery node, which is commonly seen in preferential growth networks. Moreover, we suggest a model that dynamically controls the spread of the worm using information about the depth distribution of delivery. We also verified via simulation that the load for each node was minimized at an optimal depth to effectively restrain the spread of the worm.

Mean Relative Intensity Noise Transfer in Fiber Raman Amplifiers Using Multiple-Wavelength Pumps

We present a numerical analysis of mean relative intensity noise (RIN) transfer in a fiber Raman amplifier (FRA) using multiple-wavelength pumps. For the first time, the RIN transfer is investigated to include pump-to-pump and signal-to-signal RIN transfers, together with the ldquotraditionalrdquo pump, to signal transfer in a multiple-wavelength pumped FRA. We show that for a multiple-wavelength pumped FRA, pump-to-pump and signal-to-signal RIN transfers induce an increase of RIN transfer magnitude. For a multiple-wavelength counter pumped FRA, in additional to the major pump to signal RIN transfer, pump-to-pump RIN transfer is considerable, and signal-to-signal RIN transfer is very small. For a multiple-wavelength co-pumped FRA, both pump-to-pump and signal-to-signal RIN transfers increase RIN transfer magnitude significantly. In addition, for both a co- and counter pumped FRAs, particularly for the co-pumped FRA, the longer wavelength signals experience more RIN transfer than the shorter wavelength signals. Furthermore, the bandwidth of RIN transfer is significantly increased in a multiple-wavelength co-pumped FRA with multiple input signals compared to a single-wavelength co-pumped FRA with an input signal.

Efficient SIMDization and Data Management of the Lattice QCD Computation on the Cell Broadband Engine

Lattice Quantum Chromodynamic (QCD) models subatomic interactions based on a four-dimensional discretized space–time continuum. The Lattice QCD computation is one of the grand challenges in physics especially when modeling a lattice with small spacing. In this work, we study the implementation of the main kernel routine of Lattice QCD that dominates the execution time on the Cell Broadband Engine. We tackle the problem of efficient SIMD execution and the problem of limited bandwidth for data transfers with the off-chip memory. For efficient SIMD execution, we present runtime data fusion technique that groups data processed similarly at runtime. We also introduce analysis needed to reduce the pressure on the scarce memory bandwidth that limits the performance of this computation. We studied two implementations for the main kernel routine that exhibit different patterns of accessing the memory and thus allowing different sets of optimizations. We show the attributes that make one implementation more favorable in terms of performance. For lattice size that is significantly larger than the local store, our implementation achieves 31.2 GFlops for single precision computations and 16.6 GFlops for double precision computations on the PowerXCell 8i, an order of magnitude better than the performance achieved on most general-purpose processors.

Femtosecond Charge Transfer in Assemblies of Discotic Liquid Crystals

The electronic coupling strength within columns of discotic liquid crystals is investigated using core-level resonant photoemission spectroscopy. Coexisting well-ordered and disordered regions are identified in thin films of tetra-alkoxy-substituted phthalocyanines with the aid of near edge X-ray absorption fine structure and photoelectron spectroscopies. These different regions are used to derive a lower limit for the intermolecular charge transfer bandwidth within the framework of the core-hole clock principle. We find average charge transfer times on the order of a few femtoseconds, that is, significantly faster than the C(1s) core-hole lifetime, which indicates a surprisingly strong electronic coupling between the phthalocyanine units as compared to what is expected from the charge transport characteristics of this material.

Replica selection strategies in data grid

Replication in Data Grids reduces access latency and bandwidth consumption. When different sites hold replicas of datasets, there is a significant benefit realized by selecting the best replica. By selecting the best replica, the access latency can be minimized. In this research, we propose two different replica selection techniques. To select the best replica from information gathered locally, a simple technique called the k -Nearest Neighbor (KNN) rule is exploited. The KNN rule selects the best replica for a file by considering previous file transfer logs indicating the history of the file and those nearby. We also propose a predictive technique to estimate the transfer time between sites. The predicted transfer time can be used as an estimate of transfer bandwidth of different sites that hold replica currently, and help in selecting the best replica among different sites. Simulation results demonstrate that the k -nearest algorithm shows a significant performance improvement over the traditional replica catalog based model. Besides, the neural network predictive technique estimates the transfer time among sites more accurately than the multi-regression model.

A hierarchical pipelining architecture and FPGA implementation for lifting-based 2-D DWT

Numerous VLSI architectures for 2-D discrete wavelet transform (DWT) have been brought forward. While most of the designs displayed good performance through parallel processing, few of them addressed thoroughly how to sustain such high throughput computing which is crucial in real-time applications. Although the affordable data transfer bandwidth has been increased tremendously during the past decade, the pressure on data communication has not yet been relieved from stream-intensive applications. The design of 2-D DWT belongs to such cases. In this paper, we expose the performance gap between the computing core and the entire system, distinguishing them by quantitative approach with metrics of peak performance and mean-time performance. In order to narrow down the discrepancy without degrading either of the two criteria, on the one hand, we introduce a software-pipelining lifting-based computing kernel to remove data dependence for peak performance, on the other hand, we apply loop fusing technique and a hierarchical pipelining method to enhance data locality and boost the mean-time performance. The architecture has been implemented in Xilinx Virtex-II FPGA, taking advantage of Virtex-II’s embedded multipliers and block RAMs. We use Daubechies (9, 7) and LeGall (5, 3) filters (the default lossy and lossless filters in JPEG2000) for illustration whereas it is a general method for other DWT filters. The post-place and routing operation frequency for Daubechies (9, 7) is 138 MHz. Notably, the mean-time performance parameterized by image size and decomposition level achieves closely to peak performance.

J-ONLY-TOCSY: Efficient suppression of RDC-induced transfer in homonuclear TOCSY experiments using JESTER-1-derived multiple pulse sequences

The main purpose of homonuclear Hartmann–Hahn or TOCSY experiments is the assignment of spin systems based on efficient coherence transfer via scalar couplings. In partially aligned samples, however, magnetization is also transferred via residual dipolar couplings (RDCs) and therefore through space correlations can be observed in COSY and TOCSY experiments that make the unambiguous assignment of covalently bound spins impossible. In this article, we show that the JESTER-1 multiple pulse sequence, originally designed for broadband heteronuclear isotropic Hartmann–Hahn transfer, efficiently suppresses the homonuclear dipolar coupling Hamiltonian. This suppression can be enhanced even further by variation of the supercycling scheme. The application of the resulting element in homonuclear TOCSY periods results in coherence transfer via J-couplings only. As a consequence, the assignment of scalar coupled spin systems is also possible in partially aligned samples. The bandwidth of coherence transfer for the JESTER-1-derived sequences is comparable to existing TOCSY multiple pulse sequences. Results are demonstrated in theory and experiment.

Grid-based Data Access to Nucleotide Sequence Database

The International Nucleotide Sequence Database Collaboration (INSDC) exchanges sequence data on a daily basis across its three member organizations in the USA, UK and Japan. This paper studies how this sequence database in MySQL can best take advantage of the increased transfer bandwidth of a Grid-optimized data communication protocol. Within the context of the UK Government Project Grid-oriented Storage (GOS) and the EC Project EuroAsiaGrid, GOS File System (GOS-FS) has been developed in our lab, which melds distributed file system technology with high performance data transfer techniques to meet the needs of WAN/Grid-based virtual organizations. A real-world test shows that the INSDC sequence database backing up operation, mysqldump, over the GOS-FS protocol beats those over the classic NFS protocol by 6 times over the link between Cambridge and Tokyo. Best of all, the multi-streamed GOS-FS protocol remains fully compatible with existing IP infrastructures.

Grid-Based Storage Architecture for Accelerating Bioinformatics Computing

This paper examines and investigates the relationship between bioinformatics data processing and its underlying computing architecture within the context of the International Nucleotide Sequence Database Collaboration (INSDC). INSDC exchanges sequence data on a daily basis across its three member organizations in USA, UK and Japan. We studied how this sequence database in MySQL can best take advantage of the increased transfer bandwidth of a grid-based storage architecture. Within the context of the UK Government Project "Grid-oriented Storage (GOS)" and the EC Project "EuroAsiaGrid," GOS has been developed in our lab, which melds parallel streaming technique to meet the needs of WAN/Grid-based virtual organizations. A real-world test shows that the INSDC sequence database backuping operation, mysqldump, over the pipelined GOS architecture beats those over the classic infrastructures by six times over the link between Cambridge and Tokyo. When performing genomic sequence search against one million records via the underlying GOS architecture, the performance improvement of 67.3% has been achieved.

Mean Relative Intensity Noise Transfer in Fiber Raman Amplifiers Using Multiple-Wavelength Pumps

We present a numerical analysis of mean relative intensity noise (RIN) transfer in a fiber Raman amplifier (FRA) using multiple-wavelength pumps. For the first time, the RIN transfer is investigated to include pump-to-pump and signal-to-signal RIN transfers, together with the ldquotraditionalrdquo pump, to signal transfer in a multiple-wavelength pumped FRA. We show that for a multiple-wavelength pumped FRA, pump-to-pump and signal-to-signal RIN transfers induce an increase of RIN transfer magnitude. For a multiple-wavelength counter pumped FRA, in additional to the major pump to signal RIN transfer, pump-to-pump RIN transfer is considerable, and signal-to-signal RIN transfer is very small. For a multiple-wavelength co-pumped FRA, both pump-to-pump and signal-to-signal RIN transfers increase RIN transfer magnitude significantly. In addition, for both a co- and counter pumped FRAs, particularly for the co-pumped FRA, the longer wavelength signals experience more RIN transfer than the shorter wavelength signals. Furthermore, the bandwidth of RIN transfer is significantly increased in a multiple-wavelength co-pumped FRA with multiple input signals compared to a single-wavelength co-pumped FRA with an input signal.

A Proposition of Mobile Fractal Image Decompression

A Proposition of Mobile Fractal Image DecompressionMultimedia are becoming one of the most important elements of the user interface with regard to the acceptance of modern mobile devices. The multimodal content that is delivered and available for a wide range of mobile telephony terminals is indispensable to bind users to a system and its services. Currently available mobile devices are equipped with multimedia capabilities and decent processing power and storage area. The most crucial factors are then the bandwidth and costs of media transfer. This is particularly visible in mobile gaming, where textures represent the bulk of binary data to be acquired from the content provider. Image textures have traditionally added visual realism to computer graphics. The realism increases with the resolution of textures. This represents a challenge to the limited bandwidth of mobile-oriented systems. The challenge is even more obvious in mobile gaming, where single image depicts a collection of shots or animation cycles for sprites and a backdrop scenery. In order to increase the efficiency of image and image texture transfer, a fractal based compression scheme is proposed. The main idea is to use an asymmetric server-client architecture. The resource demanding compression process is performed on the server side while the client part decompresses highly packed image data. The method offers a very high compression ratio for pictures representing image textures for natural scenes. It aims to minimize the transmission bandwidth that should speed up the downloading process and minimize the cost and time of data transfer. The paper focuses on the implementation of fractal decompression schemes suitable for most mobile devices, and opens a discussion on fractal image models for limited resource applications.

High-performance message striping over reliable transport protocols

This paper introduces a high-performance middleware-level message striping approach to increase communication bandwidth for data transfer in heterogeneous clusters equipped with multiple networks. In this scheme, concurrency is used for the striping process. The proposed striping approach is designed to work at the middleware-level, between the distributed applications and the reliable transport protocols such as TCP. The middleware-level striping approach provides flexible, scalable, and hardware-, network-, and operating systems-independent communication bandwidth solution. In addition, techniques to enhance the performance of this approach over multiple networks are introduced. The proposed techniques, which minimize synchronization contention and eliminate the striping sequence header, rely on the features of a reliable transport protocol such as TCP to reduce some of the concurrent striping overhead. The techniques have been implemented and evaluated on a real cluster with multiple networks and the results show significant performance gains for data transfer over existing approaches.

A 9.95–11.3-Gb/s XFP Transceiver in 0.13-$\mu{\hbox {m}}$ CMOS

A 9.95-11.3-Gb/s transceiver in 0.13-mum CMOS for XFP modules is presented. The CDR uses a dual-loop DLL/PLL with a binary phase detector to exceed XFP jitter specifications. The dual loop solves the problem of having a controlled jitter transfer bandwidth with a binary phase detector. A half rate binary phase detector with a 2:1 serializer implements full-rate I/O. Dispersion jitter from 12'' of FR4 is equalized resulting in system JGEN under 4 mUI <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RMS</sub> and 35 mUI <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">PP</sub> . Power consumption is 800 mW

A Low-Power Wideband Reconfigurable Integrated Active-RC Filter With 73 dB SFDR

In this paper, a low-power, highly linear, integrated, active-RC filter exhibiting a reconfigurable transfer function (Chebyshev, Elliptic) and bandwidth (5 MHz, 10 MHz), is presented. The filter exploits digitally-controlled polysilicon resistor banks and a digital automatic tuning scheme to account for process and temperature variations. The operational amplifiers used are based on a new compensation technique that allows optimized high-frequency filter performance and minimized current consumption. A filter prototype has been fabricated in a 0.12-mum CMOS process, occupies 0.25 mm2 (tuning circuit included), and achieves an IIP3 of approximately +20 dBm, whereas its spurious free dynamic range (SFDR) reaches 73 dB. The dissipation of the filter core and the tuning circuit is 4.6 mW and 1.5 mW, respectively

A 12.5-mb/s to 2.7-Gb/s continuous-rate CDR with automatic frequency acquisition and data-rate readback

A continuous-rate clock and data recovery (CDR) circuit that operates from 12.5 Mb/s to 2.7 Gb/s is described. The circuit automatically detects a change in input data rate, acquires the new frequency, and reports the data rate to the user without the need for an external reference clock or any programming. At 2.5Gb/s, it achieves an acquisition time of 1 ms. In tracking mode, it uses a dual DLL/PLL to provide superior jitter performance compared to a standard second-order loop. At the OC48 data rate, it achieves a jitter transfer bandwidth of 500 kHz and a jitter tolerance bandwidth of 3 MHz. It is on a 0.35-/spl mu/m double-poly, triple-metal (DPTM) BiCMOS process, dissipates 235 mA from a 3.3-V supply, and occupies 9 mm/sup 2/. It is in a compact 5/spl times/5 mm/sup 2/ LFCSP package.

Validation of intermolecular transfer integral and bandwidth calculations for organic molecular materials

We present an interpretation of the intermolecular transfer integral that is independent from the origin of the energy scale allowing convergence studies of this important parameter of organic molecular materials. We present extensive numerical studies by using an ethylene pi dimer to investigate the dependence of transfer integrals on the level of theory and intermolecular packing. Transfer integrals obtained from semiempirical calculations differ substantially from one another and from ab initio results. The ab initio results are consistent across all the levels used including Hartree-Fock, outer valence Green's function, and various forms of density functional theory (DFT). Validation of transfer integrals and bandwidths is performed by comparing the calculated values with the experimental values of tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ), bis[1,2,5]thiadiazolo-p-quinobis(1,3-dithiole), (BTQBT) K-TCNQ, and hexagonal graphite. DFT in one of its presently popular forms, such as Perdew-Wang functionals (PW91), in combination with sufficient basis sets provides reliable transfer integrals, and therefore can serve as a basis for energy band calculations for soft organic materials with van der Waals gaps.

Managing the optical networking solution: is increased bandwidth enough to reduce delays?

Many corporate network managers and service providers believe that more capacity can address bandwidth demands as well as delays in message transfer. As the sidebar "Optical Technology and Wavelength-Division Multiplexing" briefly describes, the solution of choice is optical technology that uses wavelength-division multiplexing (WDM). The implication of WDM is that network managers can improve their Internet application and network response time by leasing more capacity from service providers - response time being the sum of message (request and response) and application-processing delays. But although WDM transmission is promising, it presents a trade-off between bandwidth and message-transfer latency - a trade-off that is particularly significant for long-haul networks where latency begins to dominate and offset any additional bandwidth advantage for single-message transfers. To help IT network managers get the most from WDM-based technology, the authors have derived a model that establishes a boundary bandwidth for single message transfers. The boundary represents the point at which latency begins to offset any advantage from additional bandwidth. The model clearly shows that bandwidth management is as critical to the success of this technology as having access to a large supply of raw bandwidth.