Data Transfer Scheme Research Articles

A Novel Method of Wireless Data Transfer Through a Variable Focus Lens-Induced Irradiance Modulation of a Gaussian Beam

Mindful of several recent developments in the area of wireless optical data transfer over long and short distances, we present a novel technique to transmit data using an optical carrier. With this technique, the irradiance distribution of a Gaussian optical beam is controlled by passing it through an electronically controlled tunable lens (ECTL). The focal length of the ECTL is controlled by varying the root mean squared voltage of its input electrical drive signal, which alters the irradiance distribution of the Gaussian beam at any fixed plane located after the ECTL. These changes in the irradiance distribution can be interpreted as irradiance modulation with an applied input electrical signal. Variations in the input voltage signal to the ECTL result in variations in the photo-current produced inside a photo-detector of a finite active area. This paper aims to use this unique and simple method for free-space data transfer, and understand the limitations imposed by the currently available commercial ECTL technologies. With rapidly improving ECTL switching speeds and their already widespread use in mobile devices, this method promises an excellent alternative to existing point-to-point wireless data transfer schemes with minimum alterations to the existing hardware architecture of portable mobile devices.

Erasure Codes Based Adaptive Multi-hop Reliable Data Transfer for Underwater Acoustic Sensor Networks

Development of efficient techniques for improving data transmission reliability is a major concern in the design of underwater acoustic sensor networks (UWASNs). In this paper, we propose an erasure code based multi-hop reliable data transfer scheme (ECRDT) for UWASNs. ECRDT is essentially a packet level forward error correction scheme based on either end-to-end erasure coding or hop-by-hop erasure coding. In the end-to-end approach, encoding and decoding are performed by the source node and sink node, respectively, while intermediate nodes just forward the data packets without any processing. The hop-by-hop erasure coding achieves per hop reliable data transfer along the multi-hop path. In this case, apart from the source node, all intermediate nodes perform encoding process and each node is required to adaptively compute the number of redundant packets for the next hop based on the quality of the corresponding hop. We present an analytical model to find the communication overhead, energy consumption and average delay of the multi-hop UWASN under the above erasure coding approaches. Simulation and analytical results show that the proposed ECRDT scheme based on hop-by-hop erasure coding can significantly reduce communication overhead, energy consumption and average delay.

Performance Analysis of Location Privacy Preserving Scheme for MANETs

We consider the problem of preserving node's location privacy which is essential for minimizing the attacks during multi-hop routing in MANETs. As by intercepting and analyzing the transmitted packets, intermediate nodes (conventionally, assumed to be trustworthy) can track sender and receiver nodes, and can also trace the route between them. Earlier approaches attempts to preserve the location privacy by changing node-IDs or masking the location information, but results in high cost and degradation of service quality. To overcome these drawbacks, this paper presents: 1) a novel rough set based Location Privacy Preserving (LPP) scheme during route establishment; and 2) an efficient Data Transfer scheme for Location Privacy Preserving based Routes (DTLPPR) during data transfer. Analysis of trustworthiness of neighbor nodes using Discrete Time Markov Chain, and proposed scheme in terms of location privacy and route untraced ability is presented. Analytical work is validated using simulations.

Multi-GPU implementation of a VMAT treatment plan optimization algorithm

Volumetric modulated arc therapy (VMAT) optimization is a computationally challenging problem due to its large data size, high degrees of freedom, and many hardware constraints. High-performance graphics processing units (GPUs) have been used to speed up the computations. However, GPU's relatively small memory size cannot handle cases with a large dose-deposition coefficient (DDC) matrix in cases of, e.g., those with a large target size, multiple targets, multiple arcs, and/or small beamlet size. The main purpose of this paper is to report an implementation of a column-generation-based VMAT algorithm, previously developed in the authors' group, on a multi-GPU platform to solve the memory limitation problem. While the column-generation-based VMAT algorithm has been previously developed, the GPU implementation details have not been reported. Hence, another purpose is to present detailed techniques employed for GPU implementation. The authors also would like to utilize this particular problem as an example problem to study the feasibility of using a multi-GPU platform to solve large-scale problems in medical physics. The column-generation approach generates VMAT apertures sequentially by solving a pricing problem (PP) and a master problem (MP) iteratively. In the authors' method, the sparse DDC matrix is first stored on a CPU in coordinate list format (COO). On the GPU side, this matrix is split into four submatrices according to beam angles, which are stored on four GPUs in compressed sparse row format. Computation of beamlet price, the first step in PP, is accomplished using multi-GPUs. A fast inter-GPU data transfer scheme is accomplished using peer-to-peer access. The remaining steps of PP and MP problems are implemented on CPU or a single GPU due to their modest problem scale and computational loads. Barzilai and Borwein algorithm with a subspace step scheme is adopted here to solve the MP problem. A head and neck (H&N) cancer case is then used to validate the authors' method. The authors also compare their multi-GPU implementation with three different single GPU implementation strategies, i.e., truncating DDC matrix (S1), repeatedly transferring DDC matrix between CPU and GPU (S2), and porting computations involving DDC matrix to CPU (S3), in terms of both plan quality and computational efficiency. Two more H&N patient cases and three prostate cases are used to demonstrate the advantages of the authors' method. The authors' multi-GPU implementation can finish the optimization process within ∼ 1 min for the H&N patient case. S1 leads to an inferior plan quality although its total time was 10 s shorter than the multi-GPU implementation due to the reduced matrix size. S2 and S3 yield the same plan quality as the multi-GPU implementation but take ∼4 and ∼6 min, respectively. High computational efficiency was consistently achieved for the other five patient cases tested, with VMAT plans of clinically acceptable quality obtained within 23-46 s. Conversely, to obtain clinically comparable or acceptable plans for all six of these VMAT cases that the authors have tested in this paper, the optimization time needed in a commercial TPS system on CPU was found to be in an order of several minutes. The results demonstrate that the multi-GPU implementation of the authors' column-generation-based VMAT optimization can handle the large-scale VMAT optimization problem efficiently without sacrificing plan quality. The authors' study may serve as an example to shed some light on other large-scale medical physics problems that require multi-GPU techniques.

A 3.7 M-Pixel 1300-fps CMOS Image Sensor With 5.0 G-Pixel/s High-Speed Readout Circuit

A 5.0 G-pixel/s readout circuit for 15.3 mm $\times$ 8.6 mm optical size, 3.7 M-pixel, 1300 fps, and digital output image sensor for industrial applications is presented. With the column parallel ADC, the speed bottleneck is the vertical analog readout. To achieve a 5.0 G-pixel/s readout rate, a high speed column readout circuit is introduced. The novel pixel readout with the slew-enhancement and the time-interleaved correlated double sampling circuit is introduced to increase the readout rate. Besides, the A/D converter with the delay-and-gray code counter and the distributed digital data transfer schemes are innovated in order to reduce the noise interference to the foreground analog signal settling. The 1 horizontal (1H) readout time is 1.0 $\mu$ s.

Acceleration of discrete stochastic biochemical simulation using GPGPU.

For systems made up of a small number of molecules, such as a biochemical network in a single cell, a simulation requires a stochastic approach, instead of a deterministic approach. The stochastic simulation algorithm (SSA) simulates the stochastic behavior of a spatially homogeneous system. Since stochastic approaches produce different results each time they are used, multiple runs are required in order to obtain statistical results; this results in a large computational cost. We have implemented a parallel method for using SSA to simulate a stochastic model; the method uses a graphics processing unit (GPU), which enables multiple realizations at the same time, and thus reduces the computational time and cost. During the simulation, for the purpose of analysis, each time course is recorded at each time step. A straightforward implementation of this method on a GPU is about 16 times faster than a sequential simulation on a CPU with hybrid parallelization; each of the multiple simulations is run simultaneously, and the computational tasks within each simulation are parallelized. We also implemented an improvement to the memory access and reduced the memory footprint, in order to optimize the computations on the GPU. We also implemented an asynchronous data transfer scheme to accelerate the time course recording function. To analyze the acceleration of our implementation on various sizes of model, we performed SSA simulations on different model sizes and compared these computation times to those for sequential simulations with a CPU. When used with the improved time course recording function, our method was shown to accelerate the SSA simulation by a factor of up to 130.

BSIRT: a block-iterative SIRT parallel algorithm using curvilinear projection model.

Large-field high-resolution electron tomography enables visualizing detailed mechanisms under global structure. As field enlarges, the distortions of reconstruction and processing time become more critical. Using the curvilinear projection model can improve the quality of large-field ET reconstruction, but its computational complexity further exacerbates the processing time. Moreover, there is no parallel strategy on GPU for iterative reconstruction method with curvilinear projection. Here we propose a new Block-iterative SIRT parallel algorithm with the curvilinear projection model (BSIRT) for large-field ET reconstruction, to improve the quality of reconstruction and accelerate the reconstruction process. We also develop some key techniques, including block-iterative method with the curvilinear projection, a scope-based data decomposition method and a page-based data transfer scheme to implement the parallelization of BSIRT on GPU platform. Experimental results show that BSIRT can improve the reconstruction quality as well as the speed of the reconstruction process.

Efficient hardware implementation of AES algorithm using bio metric key

The innovations in technology add to the need for an enhanced security scheme for network transmission and data transfer through different channels. Biometrics is used in many novel ways to satisfy real time implications. Confidentiality and authentication of image data transfer over a network can be assured by combining biometrics and cryptography effectively. This paper proposes iris-based secured crypto system in which the application of AES algorithm along with the iris biometrics, used as the key in the algorithm. Images can be sent by the user by combining with the iris template features which are converted to 128 bit each suitable for the algorithm. Low power and faster computation techniques are enabled to increase the integrity of this scheme. Statistical analysis and attacks are performed on the key and images to prove their randomness, uniqueness and higher security levels.

A novel resource selection framework to improve QoS in computational grid

The computational grid is organised as a collection of heterogeneous resources to solve complex computational problems in scientific domains. The fundamental issue to be addressed here is the selection of appropriate compute and network resources for every submitted job. We present a novel resource selection framework, which selects trusted resources across multiple resource sites based on the computation and network capacity of the resource. We developed a new scheme for efficient data transfer in high latency wide area networks. To efficiently utilise the bandwidth of the connected resources, an improvement over the existing TCP is proposed. TCP striping aims at minimising the communication time and maximising the network utilisation. We have solved the problem of finding the optimal number of stripes considering the available bandwidth and data file size. Simulation results have shown that the proposed work completes the submitted jobs with a minimum communication time and execution time. Also, there is a significant improvement of bandwidth utilisation in high bandwidth high latency networks.

Receiving Buffer Adaptation for High-Speed Data Transfer

New applications based on cloud computing, such as data synchronization for large chain departmental stores and bank transaction records, require very high-speed data transport. Although a number of high-bandwidth networks have been built, existing transport protocols or their variants over such networks cannot fully exploit the network bandwidth. Our experiments show that the fixed-size application level buffer employed in the receiver side is a major cause of this deficiency. A buffer that is either too small or too large impairs the transfer performance. Due to the varied natures of network conditions and of real-time packet processing (i.e., consuming) speed at the receiver, it is important to ensure that the buffer size is dynamically adjusted according to the perceived execution situation during runtime. In this paper, we propose Rada, a dynamic receiving buffer adaptation scheme for high-speed data transfer. Rada employs an exponential moving average aided scheme to quantify the data arrival rate and consumption rate in the buffer. Based on these two rates, we develop a linear aggressive increase conservative decrease scheme to adjust the buffer size dynamically. Moreover, a weighted mean function is employed to make the adjustment adaptive to the available memory in the receiver. Theoretical analysis is provided to demonstrate the rationale and parameter bounds of Rada. The performance of Rada is also theoretically compared with potential alternatives. We implement Rada in a Linux platform and extensively evaluate its performance in a variety of scenarios. Experimental results conform to the theoretical results, and show that Rada outperforms the static buffer scheme in terms of throughput, memory footprint, and fairness.

Spectrally Efficient Packet Recovery in Delay Constrained Rateless Coded Multihop Networks

Rateless codes have been found to be particularly attractive for decode and forward based relaying strategy in delay tolerant multihop networks. The latency performance of such networks is dependent on the worst links that results in the starvation of subsequent nodes with good channel conditions. The total delay suffered by such networks can be constrained by limiting the number of rateless coded transmissions, especially for applications with critical latency requirements. However, the performance of rateless codes deteriorates in such circumstances due to the lack of sufficient mutual information for successfully recovering the entire source packets. The fraction of source packets that can be recovered will depend on the encoded packets received across the transmission channel. This paper investigates the degradation in the performance of such rateless coded networks by deriving the average packet recovery rate. In order to improve the reliability in such delay constrained networks, a novel spectrally efficient transmission scheme for reliable multihop data transfer is proposed. The proposed scheme exploits the broadcast nature of wireless transmissions, which provides an inherent implicit feedback channel, to ensure the reliable delivery of information packets to the nodes in the network. Rather than allocating dedicated channels to feedback the packet recovery information, the implicit feedback channel determines such information which enhances the spectral efficiency. Further, the optimum number of packets recoverable within the specified delay constraint to reduce the reprocessing of lost packets across hops is analytically analysed in this paper.

Attribute-Based Data Transfer with Filtering Scheme in Cloud Computing

Data transfer is a transmission of data over a point-to-point or point-to-multipoint communication channel. To protect the confidentiality of the transferred data, public-key cryptography has been introduced in data transfer schemes (DTSs). Data transfer is a transmission of data over a point-to-point or point-to-multipoint communication channel. To protect the confidentiality of the transferred data, public-key cryptography has been introduced in data transfer schemes (DTSs). Unfortunately, there exist some drawbacks in the current DTSs. First, the sender must know who the real receivers are. This is undesirable in a system where the number of the users is very large, such as cloud computing. In practice, the sender only knows some descriptive attributes of the receivers. Secondly, the receiver cannot be guaranteed to only receive messages from the legal senders. Therefore, it remains an elusive and challenging research problem on how to design a DTS scheme where the sender can send messages to the unknown receivers and the receiver can filter out false messages according to the described attributes. In this paper, we propose an attribute-based data transfer with filtering (ABDTF) scheme to address these problems. In our proposed scheme, the receiver can publish an access structure so that only the users whose attributes satisfy this access structure can send messages to him. Furthermore, the sender can encrypt a message under a set of attributes such that only the users who hold these attributes can obtain the message. In particular, we provide an efficient filtering algorithm for the receiver to resist the denial-of-service attacks. Notably, we propose the formal definition and security models for ABDTF schemes. To the best of our knowledge, it is the first time that a provable ABDTF scheme is proposed. Hence, this work provides a new research approach to ABDTF schemes. must know who are the real receivers. This is undesirable in a system where the number of the users is very large, such as cloud computing. In practice, the sender only knows some descriptive attributes of the receivers. Second, the receiver cannot be guaranteed to only receive messages from the legal senders. Therefore, it remains an elusive and challenging research problem on how to design a DTS scheme where the sender can send messages to the unknown receivers and the receiver can filter out false messages according to the described attributes. In this paper, we propose an attribute-based data transfer with filtering (ABDTF) scheme to address these problems. In our proposed scheme, the receiver can publish an access structure so that only the users whose attributes satisfy this access structure can send messages to him. Furthermore, the sender can encrypt a message under a set of attributes such that only the users who hold these attributes can obtain the message. In particular, we provide an efficient filtering algorithm for the receiver to resist the denial-of-service (DoS) attacks. Notably, we propose the formal definition and security models for ABDTF schemes. To the best of our knowledge, it is the first time that a provable ABDTF scheme is proposed. Hence, this work provides a new research approach to ABDTF schemes.

Energy efficient multipath data transfer scheme to mitigate false data injection attack in wireless sensor networks

Wireless sensor networks are networked systems that are deployed in an application specific region to sense the events of interest. The sensed event information has to be reported to the base station. When the event report is transmitted, adversaries can inject false event messages through compromised nodes on the path of data transfer. Falsified event messages when forwarded through en-route nodes lead to wastage of their limited energy. This study proposes a energy efficient multipath data transfer scheme to address the troubles caused by false data injection attack. This can be done by early detection and filtering of injected false data. Moreover, the multipath data transfer technique prevents the direct access of event information by a compromised en-route node. Simulations show that the proposed scheme could significantly improve the performance of false data filtering process without losing resiliency against node compromisation and data compromisation.

Extending P2PMesh: topology‐aware schemes for efficient peer‐to‐peer data sharing in wireless mesh networks

ABSTRACTWireless mesh networks (WMNs) have emerged as a promising technology that provides low‐cost broadband access to the Internet for fixed and mobile wireless end users. An orthogonal evolution in computer networking has been the rise of peer‐to‐peer (P2P) applications such as P2P data sharing. It is of interest to enable effective P2P data sharing in this type of networks. Conventional P2P data sharing systems are not cognizant of the underlying network topology and therefore suffer from inefficiency. We argue for dual‐layer mesh network architecture with support from wireless mesh routers for P2P applications. The main contribution of this paper is P2PMesh: a topology‐aware system that provides combined architecture and efficient schemes for enabling efficient P2P data sharing in WMNs. The P2PMesh architecture utilizes three schemes: (i) an efficient content lookup that mitigates traffic load imbalance at mesh routers; (ii) an efficient establishment of download paths; and (iii) a data transfer protocol for multi‐hop wireless networks with limited capacity. We note here that the path establishment and data transfer schemes are specific to P2P traffic and that other traffic would use routes determined by the default routing protocol in the WMN. Simulation results suggest that P2PMesh has the potential to improve the performance of P2P applications in a wireless multi‐hop setting; specifically, we focused on data sharing, but other P2P applications can also be supported by this approach. Copyright © 2011 John Wiley & Sons, Ltd.

A Bit-Serial Reconfigurable VLSI Based on a Multiple-Valued X-Net Data Transfer Scheme

A multiple-valued data transfer scheme using X-net is proposed to realize a compact bit-serial reconfigurable VLSI (BS-RVLSI). In the multiple-valued data transfer scheme using X-net, two binary data can be transferred from two adjacent cells to one common adjacent cell simultaneously at each “X” intersection. One cell composed of a logic block and a switch block is connected to four adjacent cross points by four onebit switches so that the complexity of the switch block is reduced to 50% in comparison with the cell of a BS-RVLSI using an eight nearest-neighbor mesh network (8-NNM). In the logic block, threshold logic circuits are used to perform threshold operations, and then their binary dual-rail voltage outputs enter a binary logic module which can be programmed to realize an arbitrary two-variable binary function or a bit-serial adder. As a result, the configuration memory count and transistor count of the proposed multiplevalued cell are reduced to 34% and 58%, respectively, in comparison with those of an equivalent CMOS cell. Moreover, its power consumption for an arbitrary 2-variable binary function becomes 67% at 800MHz under the condition of the same delay time. key words: multiple-valued data transfer scheme, X-net, multiple-valued current-mode logic, MOS current-mode logic, fine-grain reconfigurable VLSI

A Reliability Calculations Model for Large-Scale MANETs

ABSTRACT The Mobile Adhoc Network Extensibility is an issue of concern and research. The wireless network extensibility seems to be an inherent capability of MANETs taking into consideration the Multi-hop data transfer scheme. The limits of extensibility and the tradeoff between MANET stretching and the reliability concerns need to be exercised with a deterministic model. The reliability calculation methods proposed in past have an exponential growth factor for time complexity as number of nodes increase, thus making it computationally unfeasible to calculate reliability of large scale mobile networks .This work proposes a reliability calculation scheme which is realistic for calculating reliability of large scale MANETs. The proposed approach calculates the reliability of Mobile Adhoc networks by identifying critical links within a network . General Terms Reliability, Wireless Networks. Keywords Manet, Reliability, Critical Node, Two-terminal-reliability, Scalable Networks

Web Acceleration by Prefetching in Extremely Large Latency Network

A scheme for high-speed data transfer via the Internet for Web service in an extremely large delay environment is proposed. With the wide-spread use of Internet services in recent years, WLAN Internet service in high-speed trains has commenced. The system for this is composed of a satellite communication system between the train and the ground station, which is characterized by extremely large latency of several hundred milliseconds due to long propagation latency. High-speed web access is not available to users in a train in such an extremely large latency network system. Thus, a prefetch scheme for performance acceleration of Web services in this environment is proposed. A test-bed system that implements the proposed scheme is implemented and is its performance in this test-bed is evaluated. The proposed scheme is verified to enable high-speed Web access in the extremely large delay environment compared to conventional schemes.

A Data Transfer Scheme Based on Autonomous Clustering with Positions and Moving Direction of Vehicles for VANETs

A Data Transfer Scheme Based on Autonomous Clustering with Positions and Moving Direction of Vehicles for VANETs

Content Based Data Transfer Mechanism for Efficient Bulk Data Transfer in Grid Computing Environment

A new class of Data Grid infrastructure is needed to support management, transport, distributed access, and analysis of terabyte and peta byte of data collections by thousands of users. Even though some of the existing data management systems (DMS) of Grid computing infrastructures provides methodologies to handle bulk data transfer. These technologies are not usable in addressing some kind of simultaneous data access requirements. Often, in most of the scientific computing environments, a common data will be needed to access from different locations. Further, most of such computing entities will wait for a common scientific data (such as a data belonging to an astronomical phenomenon) which will be published only when it is available. These kinds of data access needs were not yet addressed in the design of data component Grid Access to Secondary Storage (GASS) or GridFTP. In this paper, we address an application layer content based data transfer scheme for grid computing environments. By using the proposed scheme in a grid computing environment, we can simultaneously move bulk data in an efficient way using simple subscribe and publish mechanism.

A multi-processor NoC-based architecture for real-time image/video enhancement

The paper presents a multi-processor architecture for real-time and low-power image and video enhancement applications. Differently from other state-of-the-art parallel architectures the proposed solution is composed of heterogeneous tiles. The tiles have computational and memory capabilities, support different algorithmic classes and are connected by a novel Network-on-Chip (NoC) infrastructure. The proposed packet-switched data transfer scheme avoids communication bottlenecks when more tiles are working concurrently. The functional performances of the NoC-based multi-processor architecture are assessed by presenting the achieved results when the platform is programmed to support different enhancement algorithms for still images or videos. The implementation complexity of the NoC-based multi-tile platform, integrated in 65 nm CMOS technology, is reported and discussed.