Low Overhead Cost Research Articles

Inter cluster communication and rekeying technique for multicast security in mobile ad hoc networks

Owing to dynamic topology changes in mobile ad hoc networks (MANETs), nodes have the freedom of movement. This characteristic necessitates the process of rekeying to secure multicast transmission. Furthermore, a secure inter cluster communication technique is also mandatory to improve the performance of multicast transmission. In this paper, we propose an inter cluster communication and rekeying technique for multicast security in MANET. The technique facilitates inter cluster communication by distributing private key shares to the nodes, which is performed by the centralised key manager. By tamper proofing the data using private key share, inter cluster communication is accomplished. Furthermore, the rekeying mechanism is invoked when a node joins the cluster. Our rekeying technique incurs low overhead and computation cost. Our technique is simulated in network simulator tool. The simulation results show the proficiency of our technique.

SOS: A Distributed Mobile Q&A SystemBased on Social Networks

Recently, emerging research efforts have been focused on question and answer (Q&A) systems based on social networks. The social-based Q&A systems can answer non-factual questions, which cannot be easily resolved by web search engines. These systems either rely on a centralized server for identifying friends based on social information or broadcast a user's questions to all of its friends. Mobile Q&A systems, where mobile nodes access the Q&A systems through Internet, are very promising considering the rapid increase of mobile users and the convenience of practical use. However, such systems cannot directly use the previous centralized methods or broadcasting methods, which generate high cost of mobile Internet access, node overload, and high server bandwidth cost with the tremendous number of mobile users. We propose a distributed Social-based mObile Q&A System (SOS) with low overhead and system cost as well as quick response to question askers. SOS enables mobile users to forward questions to potential answerers in their friend lists in a decentralized manner for a number of hops before resorting to the server. It leverages lightweight knowledge engineering techniques to accurately identify friends who are able to and willing to answer questions, thus reducing the search and computation costs of mobile nodes. The trace-driven simulation results show that SOS can achieve a high query precision and recall rate, a short response latency and low overhead. We have also deployed a pilot version of SOS for use in a small group in Clemson University. The feedback from the users shows that SOS can provide high-quality answers.

Multinational Banks and the Performance of Their Subsidiaries Abroad

This paper investigates whether foreign subsidiaries outperform their parent banks in terms of profitability and what determines this outcome. Using a sample of multinational banks and their subsidiaries in a large number of countries, this study shows that, on average, foreign subsidiaries are less profitable than their parent banks. However, the results show that foreign subsidiaries tend to perform better than their parent banks if they are well capitalized, have low overhead costs and loss low provision. I find also show that foreign subsidiaries tend to perform better than their parent banks if the latter are underperforming in the home market. While, the legal distance between host country and host country is an important determinant of the profitability of the subsidiary in relation to its parent bank, to a lesser extent, are the host market’s characteristics. Finally, foreign banks are more likely to outperform parent banks in developing markets than in developed countries. However, different bank and host country determinants influence the profitability of the subsidiaries in these countries.

Transport Information System using Query Centric Cyber Physical Systems (QCPS)

To incorporate the computation and communication with the physical world, next generation architecture i.e. CPS is viewed as a new technology. To improve the better interaction with the physical world or to perk up the electricity delivery usage, various CPS based approaches have been introduced. Recently several GPS equipped smart phones and sensor based frameworks have been proposed which provide various services i.e. environment estimation, road safety improvement but encounter certain limitations like elevated energy consumption and high computation cost. To meet the high reliability and safety requirements, this paper introduces a novel approach based on QCPS model which provides several users services (discussed in this paper). Further, this paper proposed a Transport Information System (TIS), which provide the communication with lower cost overhead by arranging the similar sensors in the form of grids. Each grid has a coordinator which interacts with cloud to process the user query. In order to evaluate the performance of proposed approach we have implemented a test bed of 16 wireless sensor nodes and have shown the performance in terms of computation and communication cost.

Efficient Hierarchical Identity-Based Encryption for Mobile Ad Hoc Networks

A Mobile Ad-hoc Network (MANET) is a collection of wireless nodes that can dynamically form a network to exchange information without using any pre-existing fixed network infrastructure. Such networks are more vulnerable to security attacks than conventional wired networks, and hence cryptographic schemes are usually used to ensure security for them. It is worth noting that the nodes in MANETs are with low computational power and communicate over relatively bandwidth constrained wireless links, and thus the deployed cryptographic schemes should usually be highly efficient in term of both computational cost and communication overhead. To ensure the data confidentiality for MANETs, in this paper, we present a new hierarchical identity-based encryption (HIBE) scheme, which enjoys the advantages of low computational cost and light communication overhead. We further propose a new hierarchical identity-based key encapsulation mechanism (HIBKEM) based on our HIBE scheme. The proposed HIBKEM scheme is fully secure against adaptive chosen-ciphertext attack, and has a tight security reduction in the standard model.

Trading Optimality for Scalability in Large-Scale Opportunistic Routing

Opportunistic routing utilizes the broadcast nature of wireless networks, significantly promoting the unicast throughput. Many variations of opportunistic routing designs have been proposed, although all of the current designs consistently rely on all of the topology information to construct forwarder lists and process data forwarding, which indeed restricts the application in large-scale wireless networks, where collecting global optimal information is very costly. In this paper, we propose the localized opportunistic routing (LOR) protocol, which utilizes the distributed minimum transmission selection (MTS-B) algorithm to partition the topology into several nested close-node-sets (CNSs) using local information. LOR can locally realize the optimal opportunistic routing for a large-scale wireless network with low control overhead cost. Since it does not use global topology information, LOR highlights an interesting tradeoff between the global optimality of the used forwarder lists and scalability inferred from the incurred overhead. Extensive simulation results show that LOR dramatically improves performances over extremely opportunistic routing (ExOR) and MAC-independent opportunistic routing protocol (MORE), which are two well-known designs from the literature, in terms of control overhead, end-to-end delay, and throughputs. It also exhibits promising performance in vehicular ad hoc networks (VANETs).

Optimizing Storage Performance for VM-Based Mobile Computing

This article investigates the transient use of free local storage for improving performance in VM-based mobile computing systems implemented as thick clients on host PCs. We use the term TransientPC systems to refer to these types of systems. The solution we propose, called TransPart , uses the higher-performing local storage of host hardware to speed up performance-critical operations. Our solution constructs a virtual storage device on demand (which we call transient storage ) by borrowing free disk blocks from the host’s storage. In this article, we present the design, implementation, and evaluation of a TransPart prototype, which requires no modifications to the software or hardware of a host computer. Experimental results confirm that TransPart offers low overhead and startup cost, while improving user experience.

Message passing interface and multithreading hybrid for parallel molecular docking of large databases on petascale high performance computing machines

A mixed parallel scheme that combines message passing interface (MPI) and multithreading was implemented in the AutoDock Vina molecular docking program. The resulting program, named VinaLC, was tested on the petascale high performance computing (HPC) machines at Lawrence Livermore National Laboratory. To exploit the typical cluster-type supercomputers, thousands of docking calculations were dispatched by the master process to run simultaneously on thousands of slave processes, where each docking calculation takes one slave process on one node, and within the node each docking calculation runs via multithreading on multiple CPU cores and shared memory. Input and output of the program and the data handling within the program were carefully designed to deal with large databases and ultimately achieve HPC on a large number of CPU cores. Parallel performance analysis of the VinaLC program shows that the code scales up to more than 15K CPUs with a very low overhead cost of 3.94%. One million flexible compound docking calculations took only 1.4 h to finish on about 15K CPUs. The docking accuracy of VinaLC has been validated against the DUD data set by the re-docking of X-ray ligands and an enrichment study, 64.4% of the top scoring poses have RMSD values under 2.0 Å. The program has been demonstrated to have good enrichment performance on 70% of the targets in the DUD data set. An analysis of the enrichment factors calculated at various percentages of the screening database indicates VinaLC has very good early recovery of actives.

Effects of scale, intensity and farm structure on the income efficiency of Irish beef farms

Data envelopment analysis (DEA) was employed to develop a model of income and scale efficiency for Irish beef farms. The objective was to identify and quantify management, farm structural and intensity indicators of efficiency for over 400 representative farms over two production systems and two years. Bootstrapping techniques were employed to measure and correct efficiency scores for sampling bias. Less than 10% of the sample exhibited constant or increasing returns to scale. The remaining farms exhibited decreasing returns to scale meaning that they were larger than optimal scale. Greater income efficiency was associated with lower levels of concentrate feeding and lower overhead costs per livestock unit (LU). Fragmentation, paid labour and capital investment were significantly negatively associated with income efficiency. There was a positive relationship between market gross output per LU and income efficiency. Negative market net margins tended to be subsidised by greater off-farm income on smaller (more scale efficient) farms and by greater direct payments on larger (more scale inefficient) farms. Consequently, prospects for increasing beef output via scale expansion are negative in an external environment of declining subsidies and reduced off-farm employment in rural areas. Increased output from Irish beef farms must therefore come primarily from farm system structural changes rather than scale changes, otherwise farm income efficiency will decline.

Biorremediación en suelos contaminados con hidrocarburos en Colombia

Se revisan los procesos de Biorremediación de suelos contaminados con hidrocarburos en Colombia, como una alternativa sostenible frente al deterioro progresivo de la calidad del medio ambiente por el derrame de hidrocarburos. En la legislación ambiental en Colombia y en el mundo, todo residuo contaminado con hidrocarburos es considerado un residuo peligroso; por lo tanto, no puede ser dispuesto en suelo, aguas o incinerado a cielo abierto, lo que ha motivado a empresas del país en el mundo a implementar procesos de tratamiento de lodos contaminados. En Colombia las empresas petroleras, han venido implementando la biorremediación de lodos contaminados con hidrocarburos como alternativas, para el manejo de residuos resultantes de los derrames que se presentan en las actividades de explotación, refinación, transporte y distribución del producto. Estas prácticas deben ser consideradas sustentables por su fácil implementación, por los bajos costos que generan la operación y aplicación del proceso y por el beneficio para el medio ambiente. Entre los impactos positivos que estas prácticas han generado, se puede considerar las siguientes: solución a la problemática de generación de lodos contaminados con hidrocarburos, alternativas<br />de disposición final de los mismos sin afectar los recursos suelo, agua y aire, el bajo costo en la operación y experiencia técnica de desarrollo sostenible que puede continuar implementándose en empresas similares donde se presenten este tipo de residuos peligrosos.

Algorithm for Linear Number Partitioning into Maximum Number of Subsets

The number partitioning problem is to decide whether a given multiset of integers can be partitioned into two halves of given cardinalities such that the discrepancy, the absolute value of the difference of their sums is minimized. While Partitioning problem is known to be NP-complete, only few studies have investigated on its variations. Number partitioning problem has a wide range of practical application, like: multiprocessor scheduling, minimization of VLSI circuit size and delay, also used in public key cryptography, message verification, computer password, voting manipulation and bin packing. While lots of investigation have been made for two-way partitioning, only a few for multi-way partitioning, while most of them are not feasible for real time environment. We introduce an improved multi-way partitioning algorithm which is feasible for real time environment. It returns maximum number of subset that can be made based on the order of the numbers as they appear. Maximum number of subset helps us to preempt any process & serve higher priority process with extremely low overhead cost in multiprocessor process scheduling.

WHO's relationship with the Stop TB Partnership

WHO's relationship with the Stop TB Partnership

The Design and Implementation of ECC High-Speed Encryption Engine Based on FPGA

Network security technology ensures secure data transmission in network. Meanwhile, it brings extra overhead of security system in terms of cost and performance, which seriously affects the rapid development of existing high-speed encryption systems. The existing encryption technology cannot meet the demand of high security, low cost and high real-time. For solving above problems, an ECC encryption engine architecture based on scalable public key cipher and a high-speed configurable multiplication algorithm are designed. The algorithm was tested on FPGA platform and the experiment results show that the system has better computation speed and lower cost overhead. By comparing with other systems, our system has benefits in terms of hardware overhead and encryption time ratio

Combining dynamical decoupling with fault-tolerant quantum computation

We study how dynamical decoupling (DD) pulse sequences can improve the reliability of quantum computers. We prove upper bounds on the accuracy of DD-protected quantum gates and derive sufficient conditions for DD-protected gates to outperform unprotected gates. Under suitable conditions, fault-tolerant quantum circuits constructed from DD-protected gates can tolerate stronger noise, and have a lower overhead cost, than fault-tolerant circuits constructed from unprotected gates. Our accuracy estimates depend on the dynamics of the bath that couples to the quantum computer, and can be expressed either in terms of the operator norm of the bath's Hamiltonian or in terms of the power spectrum of bath correlations; we explain in particular how the performance of recursively generated concatenated pulse sequences can be analyzed from either viewpoint. Our results apply to Hamiltonian noise models with limited spatial correlations.

Design and Implementation of a Nonblocking 2-Dilated Flattened Butterfly Switching Network

High-performance computing is highly dependent on the communication network connecting the nodes. In this paper, we present a design and implementation of the 2-dilated flattened butterfly (2DFB) network topology, which provides nonblocking performance for relatively low cost overhead. The flattened butterfly is known to be a cost efficient topology for high-radix networks. Because of its inherent path diversity, it is able to provide comparable cost/performance with the folded-Clos network in adversarial traffic conditions. However, the flattened butterfly is a blocking network and this blocking behavior can degrade the performance of the network when all compute nodes are transmitting and receiving data at full bandwidth. 2DFB network exhibits nonblocking behavior which is a critical factor in deciding the quality of any high performance computing system network. We have implemented the network using the NetFPGA as the switching element and verified the nonblocking behavior of 2DFB. We also compare the performance of a 2DFB with other switching networks. We also show that the 2DFB topology can be used to build high speed switching systems with reduced cost.

2-Dilated flattened butterfly: A nonblocking switching topology for high-radix networks

High-performance computing is highly dependent on the communication network connecting the nodes. In this paper, we propose a 2-Dilated flattened butterfly (2DFB) network which provides non-blocking performance for relatively low cost overhead. We study the topological properties of the proposed 2DFB network and compare it with different nonblocking switching topologies. We observe that a dilation factor of two is sufficient to obtain nonblocking property for a flattened butterfly structure irrespective of its size or dimension. Dilating each link in a flattened butterfly causes an increase in cost. Therefore, we modeled the implementation cost of a 2DFB network and compared it with other popular nonblocking networks. We observe that the cost of a 2DFB is less than other nonblocking networks, while at the same time providing reduced latency because of its reduced diameter and hop count. We also propose a procedure to develop a conflict-free static routing schedule as well as an adaptive load balanced routing scheme (ALDFB) for 2DFB networks. Finally, we also describe the hardware implementation of a 2DFB network using the NetFPGA as the switching element and verify the nonblocking behavior of a 2DFB. We also show that the 2DFB topology can be used to build high speed switching systems with reduced cost.

SAAMAN: Scalable Address Autoconfiguration in Mobile Ad Hoc Networks

Address autoconfiguration is one of the fundamental issues in mobile ad hoc networks (MANET). A node must need some form of identity before participating in any sort of communication. So each host in a MANET needs to be uniquely addressed so that the packets can be relayed hop-by-hop and delivered ultimately to the desired destination. Moreover, nodes in the MANET are free to move and organize themselves in an arbitrary fashion. Therefore any fixed infrastructure based solution for assigning identity (i.e. IP address) is not directly applicable to MANET. Under this infrastructureless and sporadic nature of the mobile nodes, several protocols of address autoconfiguration in the mobile ad hoc networks (MANET) have been proposed. Although some of these protocols perform decently in sparse and small networks, but exhibit poor performance (e.g., single point of failure, storage limitation, large protocol overhead and so on) when the network is either dense or very large. In this paper, we propose an efficient and scalable address autoconfiguration protocol that automatically configures a network by assigning unique IP addresses to all nodes with a very low overhead and minimal cost. Evenly distributed Duplicate-IP address Detection Servers are used to ensure the uniqueness of an IP address during IP address assignment session. In contrast to some other solutions, the proposed protocol does not exhibit any problems pertaining to leader election or centralized server-based solutions. Furthermore, grid based hierarchy is used for efficient geographic forwarding as well as for selecting Duplicate-IP address Detection Servers. Through simulation results we demonstrate scalability, robustness, low latency, fault tolerance and some other important aspects of our protocol.

Multinational Banks and the Performance of Their Subsidiaries Abroad

This paper investigates whether foreign subsidiaries outperform their parent banks in terms of profitability and what determines this outcome. Using a sample of multinational banks and their subsidiaries in a large number of countries, this study shows that, on average, foreign subsidiaries are less profitable than their parent banks. However, the results show that foreign subsidiaries tend to perform better than their parent banks if they are well capitalized, have low overhead costs and loss low provision. I find also show that foreign subsidiaries tend to perform better than their parent banks if the latter are underperforming in the home market. While, the legal distance between host country and host country is an important determinant of the profitability of the subsidiary in relation to its parent bank, to a lesser extent, are the host market’s characteristics. Finally, foreign banks are more likely to outperform parent banks in developing markets than in developed countries. However, different bank and host country determinants influence the profitability of the subsidiaries in these countries.

Subway Productivity, Profitability, and Performance

Detailed comparative analyses of New York City subways and four Southeast Asian transit systems revealed that Hong Kong's subways are profitable because of high asset productivity resulting from a strategic “prudent commercial” design for high utilization and traffic density. Hong Kong subways also have a land-grant financing framework, a relatively high degree of commercial freedom, and relatively low overhead costs and asset replacement needs. Conversely, Singapore and Taipei, Taiwan, subways are operated by concessioned carriers (akin to New York's historic Interborough Rapid Transit and Brooklyn–Manhattan Transit) and are not profitable when government-provided initial capital construction funds are accounted for at typical government bond interest rates. Infrastructure ownership was separated to attract investors and allow government-controlled carriers to function as quasi-private entities. Network design choices with consequences for density and use explain the higher productivity in Asia. New York's system was not designed for maximum capital and operating cost efficiency or productivity but to provide high coverage and service levels at lower traffic densities in a socially conscious and inclusive approach, whereas the Taiwan and Singapore governments made design decisions and chose governance structures that enabled higher productivity. Asian systems operate more reliably than New York's 100-year-old subway because of modern design parameters, advanced technology, and different legal frameworks and management processes. State-of-good-repair issues that plagued 1970s New York have yet to surface in Asia. Direct comparisons in performance, profitability, and productivity should be avoided unless care is taken to analyze effects of governance, social contexts, design criteria, and reasons for their differences. Nonetheless, comparisons and benchmarking can yield valuable insights for operations improvement under prevailing local constraints.

A Configurable Heterogeneous Multicore Architecture With Cellular Neural Network for Real-Time Object Recognition

As object recognition requires huge computation power to deal with complex image processing tasks, it is very challenging to meet real-time processing demands under low-power constraints for embedded systems. In this paper, a configurable heterogeneous multicore architecture with a dual-mode linear processor array and a cellular neural network on the network-on-chip platform is presented for real-time object recognition. The bio-inspired attention-based object recognition algorithm is devised to reduce computational complexity of the object recognition. The cellular neural network is utilized to accelerate the visual attention algorithm for selecting salient image regions rapidly. The dual-mode parallel processor is configured into single instruction, multiple data (SIMD) or multiple-instruction-multiple-data modes to perform data-intensive image processing operations while exploiting pixel-level and feature-level parallelisms required for the attention-based object recognition. The algorithm's hybrid parallelization strategy on the proposed architecture is adopted to obtain maximum performance improvement. The performance analysis results, using a cycle-accurate architecture simulator, show that the proposed architecture achieves a speedup of 2.8 times for the target algorithm over conventional massively parallel SIMD architecture at low hardware cost overhead. A prototype chip of the proposed architecture, fabricated in 0.13 mum complementary metal-oxide-semiconductor technology, achieves 22 frames/s real-time object recognition with less than 600 mW power consumption.