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This paper applies data envelopment analysis (DEA) to provide efficiency measurement for Shenzhen port in different years. DEA with cross evaluation has been applied to efficiency comparisons between five ports. The DEA technique is useful in resolving the measurement of port efficiency because the calculations are non-parametric, can handle more than one output and do not require an explicit a priori...
We present the design of hollow near-field scanning microscope (NSOM) probe with nanogratings-on-tip to transport and concentrate localized surface plasmonic polariton (SPP) wave. By adding nano-grooves started from the intensity-maximum locations of lowest transmission mode and with pitch period supporting the metal-air interface SPP mode, the power throughput is increased at over 530 times comparing...
This paper investigates the maximal achievable multi-rate throughput problem of a multicast session at the presence of network coding. Deviating from previous works which focus on single-rate network coding, our work takes the heterogeneity of sinks into account and provides multiple data layers to address the problem. Firstly formulated is the maximal achievable throughput problem with the assumption...
This paper presents the issue of capacity variable routing in Satellite-HAP system networks with multicasting capabilities, for different traffic types, with the objective of minimizing the short term traffic load oscillations and reacting to the long term changes of the traffic loads. This is realized by learning from the past and using it to influence the current decision. Some of the major QOS...
System capacity is an important factor that affects the performance of WiMAX system where the amount of data that can be delivered to the end user is determined based on the system capacity and users QoS requirements. This scenario is even more complex when multi-hop relays are introduced into the network whereas the user access capacity decreases with the increase of hop number. In order to maintain...
IEEE 802.15.4 defines the physical layer and medium access control sub-layer specifications for low-data-rate wireless connectivity devices with very limited battery consumption requirements typically operating in the personal operating space. Unlike traditional wireless networks, its unique characteristics, such as low-data-rate and guaranteed time slots (GTS), have brought unprecedented challenges...
In Vehicular Ad Hoc Network (VANET), the route between a source node and a destination node is intermittently broken. It is difficult to provide the reliable data transfer based on TCP because TCP is not adaptable to such networks such as VANET. Therefore, this paper proposes an end-to-end transfer rate adjustment mechanism in the application layer for VANET. The proposed mechanism consists of three...
Multi-channel assignment schemes have recently been proposed to improve the network throughput of multi-hop wireless mesh networks (WMNs). In these schemes, channel coordination is done either through time synchronization across all the nodes, or through the use of a dedicated channel for the transmission of necessary control messages. Either way, excessive system overhead or waste of bandwidth resource...
Advanced Encryption Standard (AES) and state of art technology FPGAs (Field Programmable Gate Arrays) can be used together to mitigate the potential threats of interception of Satellite data and unauthorized access to the Satellite System. This paper discusses the implementation and verification of AES algorithm on Virtex 4 FPGA and its usage in the protection of Remote Sensing Satellite Data. The...
A real time distributed computing system has heterogeneously connected computers to solve a single problem. If the transactions run across different sites, it may commit at one site and may get fail at other site, leading to an inconsistent transaction. The transaction in a real time database system has deadlines to process the workloads and it need to process transactions before these deadlines expired...
The capacity problem is one of the main issues in researching the multi-channel IEEE 802.11 wireless networks. In this paper, we analyze the path capacity of the multi-channel wireless networks by estimating the RTS, CTS and the packet loss rate of the wireless links and calculating the average service time of the packet sending. We also analyze the channel assignment and channel switching problems...
In this paper we develop a discrete and distributed optimization framework that maximizes the overall spectral efficiency of heterogeneous networks while ensuring a minimum fairness among users. We split the problem into two subproblems: the first one is handled by the users and consists in a transmission by each user of a minimum rate requirement to the base stations and the second is the resource...
Base station cooperation is a promising solution to the interference limitation of today's cellular networks. The capacity and fairness gains shown by information theoretical analysis of base station cooperation in cellular networks are huge. However, a major downside is the information exchange among base stations, which is the motivation for recent work on backhaul efficient cooperation schemes...
In this paper present performance comparison of AODV and OLSR for mobile ad hoc network. Though mobile ad hoc network (MANET) routing protocols have been extensively studied through simulation. We perform extensive simulations using NS-2 simulator. In particular, We look at average throughput as performance parameters while varying various network parameters such as number of nodes and pause time...
This paper presents a new steganographic method called WiPad (Wireless Padding). It is based on the insertion of hidden data into the padding of frames at the physical layer of WLANs (Wireless Local Area Networks). A performance analysis based on a Markov model, previously introduced and validated by the authors in, is provided for the method in relation to the IEEE 802.11 a/g standards . Its results...
This paper presents experimental results of the implementation of network steganography method called RSTEG (Retransmission Steganography). The main idea of RSTEG is to not acknowledge a successfully received packet to intentionally invoke retransmission. The retransmitted packet carries a steganogram instead of user data in the payload field. RSTEG can be applied to many network protocols that utilize...
Wireless networks with the shared media require Medium Access Control (MAC) protocol that provides contention resolution mechanism. The design of MAC protocol in underwater sensor networks is a challenging issue because of limited energy source and high propagation delay. The most important goal of the MAC design for underwater sensor networks is to resolve data packet collision efficiently with respect...
The number of multi-homed hosts with multiple network interfaces has been increasing due to cheaper network interface devices and network diversification. Concurrent Multipath Transfer (CMT) using SCTP multihoming is a mechanism that simultaneously transmits data via multiple end-to-end paths compatible with today's network environment. Present studies on CMT have assumed that each path uses a homogeneous...
The network throughput will decrease dramatically and collision rate increases severely when active nodes increase in WLAN. Breaking through the limitation of the Binary Exponential Backoff algorithms, we provide a new backoff algorithm which utilizes the linear contention window based on the node numbers. To attain better performance, we derive that the contention window is selected as an approximate...
A new genre of P2P systems, P2P Video-on-Demand (P2P-VoD), has not only received substantial recent research attention, but also been implemented and deployed with success in large-scale real-world streaming systems, such as PPLive. The essential characterization of P2P-VoD systems is to take full advantage of peer upload bandwidth contribution with a cache on each peer. Meanwhile, the asynchronous...
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