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The handoff rate is identified in a hybrid channel allocation algorithm of a wireless and mobile network. In this network model, both new calls and handoff calls to a cell have possibilities to borrow channels from the control center if all allocated channels to the cell are used up. In addition, there is a buffer with finite size reserved exclusively for handoff calls in a cell when they arrived but are not be able to borrow channels from the control center. In this paper, we derived a novel and theoretical expression of the handoff rate in the network first. This analytical expression for handoff rate is a general form which covers several special cases discussed in the literature. Then, an efficient iterative algorithm to calculate this handoff rate is proposed also. By using this algorithm, the handoff rate and the blocking probability of both new calls and handoff calls will be successfully derived at the same time. Furthermore, our numerical analysis validates the algorithm and the corresponding theoretic expression. [ABSTRACT FROM AUTHOR]

Internet of Things (IoT) applications are connecting several Mobile Stations (MSs) to form the Mobile Communication Network (MCN). MSs are moving through macrocell and picocell recurrently due to the discontinuous deployment of the picocell over the macrocell. Each time they cross the cell boundary, they need to register with the Mobility Management Entity (MME). It incurs a high registration cost and elevates the signaling overhead ratio. To reduce the signaling overhead ratio, earlier techniques were attempted either by forming closed subscriber groups or by delaying the registration process, but that may create inconsistency in user location information. With this motivation, in this paper, MSs with similar mobility pattern which are moving from the picocell to macrocell, are grouped in clusters. A representative MS, called Cluster Representative (CR), performs the location management task on behalf of the whole cluster. The stochastic process has been employed to analyze the model. This study proposes Cluster-Based Location Management (CBLM) scheme and compares it with two state-of-the-art algorithms, named Group Mobility Management (GMM) and Closed Subscriber Group (CSG). On average, the CBLM scheme exhibits approximately 70% better performance than the CSG scheme whereas, 30% better than the GMM algorithm to mitigate the signaling overhead. [ABSTRACT FROM AUTHOR]

A lot of schemes have been proposed for the establishment of u-city. Especially, most of the schemes are based on ubiquitous networks. In this paper, it is assumed that the ubiquitous networks include some mobile agents. Therefore, an intelligent positioning scheme is proposed for the efficient positioning of the mobile agents in the ubiquitous networks. The approach consists of location detection and location tracking. Furthermore, an optimal diversity technique is presented in this paper to improve the positioning performance. Simulation results indicate that using the suggested algorithms, the excellent detection and tracking performance can be achieved in ubiquitous networks for u-city. [ABSTRACT FROM AUTHOR]

Self-stabilization is a theoretical framework of non-masking fault-tolerant distributed algorithms. A self-stabilizing system tolerates any kind and any finite number of transient faults, such as message loss, memory corruption, and topology change. Because such transient faults occur so frequently in mobile ad hoc networks, distributed algorithms on them should tolerate such events. In this paper, we propose a self-stabilizing distributed approximation algorithm for the minimum connected dominating set, which can be used, for example, as a virtual backbone or routing in mobile ad hoc networks. The size of the solution by our algorithm is at most 7.6|Dopt|+1.4, where Dopt is the minimum connected dominating set. The time complexity is O(k) rounds, where k is the depth of input BFS tree. [ABSTRACT FROM AUTHOR]

This paper presents a multimodal approach for a biometrics verification system. It is based on face and hand images captured by a cell phone. The algorithm includes all parts that are required for face and hand verification, such as feature extraction, classification and authentication. To find local facial features, such as eyes, mouth and nose, we apply a point distribution model and active shape models. We use the same system to find distinctive points in hand geometry. The face feature vector is constructed by applying a Gabor filter to the image and extracting the key points found by an active shape model. The palm feature vector contains characteristics of the hand geometry features. A support vector machine (SVM) is applied to verify the identity of the user. One SVM machine is built for each person in the database to distinguish that person from others. To test the algorithm we built our own database containing face and hand images taken by a cell phone camera. The database contains 480 frontal face images and 120 hand images of 30 persons (16 face images and 4 hand images per person). [ABSTRACT FROM AUTHOR]

In this paper, two learning automata based adaptive limited fractional guard channel algorithms for cellular mobile networks are proposed. These algorithms try to minimize the blocking probability of new calls subject to the constraint on the dropping probability of the handoff calls. To evaluate the proposed algorithms, computer simulations are conducted. The simulation results show that the performance of the proposed algorithms are close to the performance of the limited fractional guard channel algorithm for which prior knowledge about traffic parameters are needed. The simulation results also show that the proposed algorithms outperforms the recently introduced dynamic guard channel algorithms. [ABSTRACT FROM AUTHOR]

This paper proposes a hybrid estimation of distribution algorithm (HyEDA) to address the design problem of code division multiple access cellular system configuration. Given a service area, the problem is to find a set of optimal locations of base stations, associated with their corresponding powers and antenna heights in the area, in order to maximize call quality and service coverage, at the same time, to minimize the total cost of the system configuration. HyEDA is a two-stage hybrid approach which integrates an estimation of distribution algorithm, a K-means clustering method, and a simple local search algorithm. We have compared HyEDA with a simulated annealing method on a number of instances. Our simulation results have demonstrated that HyEDA outperforms the simulated annealing method in terms of the solution quality and computational cost. [ABSTRACT FROM AUTHOR]

Mobile communication has a great potential to the users due to fulfilling the dreams of real-time multimedia communication like voice, image, and text. The huge amount of data redundancy in still image should be compressed using exact image compression algorithm (ICA) before transmitting via wireless channel. Thus, an ICA should be adaptive, simple, and cost-effective and suitable for feasible implementation. Hardware implementation of the different algorithms has improved using modern, fast, and cost-effective technologies. The main aim of this paper is to review and demonstrate various ICAs developed based on image transmission via wireless channel as well as their hardware implementation. Finally, this review makes bridge for researchers to the future relative studies between different algorithms and architectures, and stands as a reference point for developing more controlling and flexible structures. [ABSTRACT FROM AUTHOR]

This paper describes AntHocNet, an algorithm for routing in mobile ad-hoc networks based on ideas from the ant colony optimisation framework. In AntHocNet a source node reactively sets up a path to a destination node at the start of each communication session. During the course of the session, the source node uses ant agents to proactively search for alternatives and improvements of the original path. This allows to adapt to changes in the network, and to construct a mesh of alternative paths between source and destination. The proactive behaviour is supported by a lightweight information bootstrapping process. Paths are represented in the form of distance-vector routing tables called pheromone tables. An entry of a pheromone table contains the estimated goodness of going over a certain neighbour to reach a certain destination. Data are routed stochastically over the different paths of the mesh according to these goodness estimates. In an extensive set of simulation tests, we compare AntHocNet to AODV, a reactive algorithm which is an important reference in this research area. We show that AntHocNet can outperform AODV for different evaluation criteria in a wide range of different scenarios. AntHocNet is also shown to scale well with respect to the number of nodes. [ABSTRACT FROM AUTHOR]

In this paper, we present a self-stabilizing algorithm for finding cut-nodes and bridges in arbitrary rooted networks with a low memory requirement (O(log(n)) bits per processor where n is the number of processors). Our algorithm is silent and must be composed with a silent self-stabilizing algorithm computing a Depth-First Search (DFS) Spanning Tree of the network. So, in the paper, we will prove that the composition of our algorithm with any silent self-stabilizing DFS algorithm is self-stabilizing. Finally, we will show that our algorithm needs O(n2) moves to reach a terminal configuration once the DFS spanning tree is computed. Note that this time complexity is equivalent to the best proposed solutions. [ABSTRACT FROM AUTHOR]

This paper describes a single DSP implementation of a realtime 3D sound synthesis algorithm dedicatedly for mobile applications. This approach is distinctive in that the audible frequency band is divided into three subbands in such a way that, given a head-related transfer function (HRTF), the portion of the functional behavior in each subband can be realized efficiently by a distinct digital filtering structure. The whole digital filters are implemented on a commercially available 16-bit fixed-point DSP, taking account of three major design factors of memory size, calculation accuracy, and computational complexity. As a result, the realtime 3D sound synthesis is achieved by employing a single DSP with the low computational labor of 51.3 MIPS and the small memory space of 4.6 k words. [ABSTRACT FROM AUTHOR]

In this paper we consider a network where an intruder is moving "contaminating" the nodes it passes by, and we focus on the problem of decontaminating such a network by a team of mobile agents. The contamination/decontamination process has the following asynchronous dynamics: when the team is deployed all nodes are assumed to be contaminated, when an agent transits on a node, it will clean the node, when the node is left with no agent, the node will be recontaminated as soon as at least one of its neighbours is contaminated. We study the problem in asynchronous chordal ring networks and in tori. We consider two variations of the model: one where agents have only local knowledge, the other in which they have "visibility", i.e., they can "see" the state of their neighbouring nodes. We first derive lower bounds on the minimum number of agents necessary for the decontamination. In the case of chordal rings we show that the number of agents necessary to perform the cleaning does not depend on the size of the network; in fact it is linear in the length of the longest chord (provided that it is not too long). In the case of a torus, the minimum number of agents is equal to 2 · h, where h is the smallest dimension. We then propose optimal strategies for decontamination and we analyse the number of moves and the time complexity of the decontamination algorithms, showing that the visibility assumption allows us to decrease substantially both complexity measures. Another advantage of the "visibility model" is that agents move independently and autonomously without requiring any coordination. [ABSTRACT FROM AUTHOR]

Recent studies have revealed that deadlocks are generally infrequent in the network. Thus the hardware resources, e.g. virtual channels, dedicated for deadlock avoidance are not utilised most of the time. This consideration has motivated the development of novel adaptive routing algorithms with deadlock recovery. This paper describes a new analytical model to predict message latency in hypercubes with a true fully adaptive routing algorithm with progressive deadlock recovery. One of the main features of the proposed model is the use of results from queueing systems with impatient customers to capture the effects of the timeout mechanism used in this routing algorithm for deadlock detection. The validity of the model is demonstrated by comparing analytical results with those obtained through simulation experiments. [ABSTRACT FROM AUTHOR]

This paper describes a threshold-based wake-up mechanism to reduce the battery power consumption of a mobile data handset. The threshold approach switches the system into the sleep mode when the memory queue for arriving packets is empty, and switches on the system when the number of packets in the memory queue is above a threshold value. We propose several adaptive schemes capable of dynamically selecting the threshold value for the threshold approach. An adaptive algorithm adjusts the threshold value based on a pre-defined packet-dropping probability, for which the switch-on rate is kept reasonably small to maintain the actual packet-dropping probability as close as the pre-defined value. Two strategies are used in the adaptive algorithm to adjust the threshold value: binarydivision and fixed-amount. Two calculation strategies are considered to measure the packet-dropping probability: window-averaging and leaky-bucket integration (LBI). Our study indicates that the binary-division strategy outperforms the fixed-amount strategy in adjusting the threshold value. Furthermore, with proper setting, the LBI strategy outperforms the window-averaging strategy. [ABSTRACT FROM AUTHOR]