THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

"A Survey of Mobility Models for Ad Hoc Network Research," Wireless Comm. & Mobile Computing (WCMC) : Special issue on Mobile Ad Hoc Networking : Research

In the performance evaluation of a protocol for an ad hoc network, the protocol should be tested under realistic conditions including, but not limited to, a sensible transmission range, limited buffer space for the storage of messages, representative data traffic models, and realistic movements of the mobile users (i.e., a mobility model). This paper is a survey of mobility models that are used in the simulations of ad hoc networks. We describe several mobility models that represent mobile nodes whose movements are independent of each other (i.e., entity mobility models) and several mobility models that represent mobile nodes whose movements are dependent on each other (i.e., group mobility models). The goal of this paper is to present a number of mobility models in order to offer researchers more informed choices when they are deciding upon a mobility model to use in their performance evaluations. Lastly, we present simulation results that illustrate the importance of choosing a mobility model in the simulation of an ad hoc network protocol. Specifically, we illustrate how the performance results of an ad hoc network protocol drastically change as a result of changing the mobility model simulated.

/pdf/a-survey-of-mobility-models-for-ad-hoc-network-research-ygkxat400x.pdf

A survey of mobility models for ad hoc network research

Mobile ad hoc routing protocols allow nodes with wireless adaptors to communicate with one another without any pre-existing network infrastructure. Existing ad hoc routing protocols, while robust to rapidly changing network topology, assume the presence of a connected path from source to destination. Given power limitations, the advent of short-range wireless networks, and the wide physical conditions over which ad hoc networks must be deployed, in some scenarios it is likely that this assumption is invalid. In this work, we develop techniques to deliver messages in the case where there is never a connected path from source to destination or when a network partition exists at the time a message is originated. To this end, we introduce Epidemic Routing, where random pair-wise exchanges of messages among mobile hosts ensure eventual message delivery. The goals of Epidemic Routing are to: i) maximize message delivery rate, ii) minimize message latency, and iii) minimize the total resources consumed in message delivery. Through an implementation in the Monarch simulator, we show that Epidemic Routing achieves eventual delivery of 100% of messages with reasonable aggregate resource consumption in a number of interesting scenarios.

/pdf/epidemic-routing-for-partially-connected-ad-hoc-networks-s5rslcaiip.pdf

Epidemic routing for partially-connected ad hoc networks

Broadcasting is a common operation in a network to resolve many issues. In a mobile ad hoc network (MANET) in particular, due to host mobility, such operations are expected to be executed more frequently (such as finding a route to a particular host, paging a particular host, and sending an alarm signal). Because radio signals are likely to overlap with others in a geographical area, a straightforward broadcasting by flooding is usually very costly and will result in serious redundancy, contention, and collision, to which we call the broadcast storm problem. In this paper, we identify this problem by showing how serious it is through analyses and simulations. We propose several schemes to reduce redundant rebroadcasts and differentiate timing of rebroadcasts to alleviate this problem. Simulation results are presented, which show different levels of improvement over the basic flooding approach.

/pdf/the-broadcast-storm-problem-in-a-mobile-ad-hoc-network-2ovgqt6pyc.pdf

The broadcast storm problem in a mobile ad hoc network

1 Introduction h this paper we introduce a new routing protocol for ad hoc networks built around two novel observations. One, called the distance eflect, usw the fmt that the greater the distance separating two nodes, the slower they appear to be moving with respect to each other. Accor@gly, the location information in routing tables can be updated as a function of the distance separating nodes without compromising the routing accuracy. The second idea is that of triggering the sending of location updates by the moving nodes autonomously, based ody on a node's mobility rate. htuitively, it is clear that in a direction routing dgorithrn, routing information about the slower moving nodes needs to be updated less frequently than that about hig~y mobtie nodw. h this way e~ node can optimize the frequency at which it sends updates to the networks and correspondingly r~ duce the bandwidth and energy used, leading to a fully distributed and self-optimizing system. B~ed on thwe routing tablw, the proposed direction algorithm sends messages in the " recorded dwectionn of the destination node, guaranteeing detivery by following the direction with a given probability. We show by detailed simda-tion that our protocol always delivers more than 80% of the data messages by following the direction computed, without using any recovery procedure. In addition, it mintilzes the overhead used for maintaining routes using the two new principlw of update message frequency and distance. Lastly, the dgorithrn is fully distributed, provides loop-free paths, and is robust, since it suppfies multiple routes. Pemlissiontomakedigitalorhsrdcopiesof allorpartof this\vorkfor personal or classroom use is granted without fee provided that copies are not mzde or dis~.buted for prolit or commercial ad~arrtageand that copies bcwrthis notice and the full citation on the first page. To copy othm}tise, to republish, to post on senrers or to redistribute to lists, requires prior specific permission an&'ora fee. 76 Rom a routing perspective, an ad hoc network is a packet radio network in which the mobile nodes perform the routing functions. Generdy, routing is multi-hop since nodes may not be within the wireless transmission range of one another and thus depend on each other to forward packets to a given destination. Since the topology of an ad hoc network changes frequently, a routing protocol should be a distributed algorithm that computes multiple, cycle free routes while keeping the communication overhead to a minimum (see, e.g., [4]). One way to …

A distance routing effect algorithm for mobility (DREAM)

Delay sensitive applications are driving the need for the support of quality-of-service (QoS) in mobile ad hoc networks. In this paper, we use statistical design of experiments to study the impact of factors and their interaction on the service delivered. We consider the factors of QoS architecture, routing protocol, medium access control protocol, offered load, and mobility, at mixed levels. Real-time throughput, total throughput, and average delay are used as the measures of service delivery. A statistical analysis of the data collected by simulation using analysis of variance techniques is performed. This allows us to identify both main effects and interactions of factors that best explain the response variables. For average delay several factors of the experiment interact. For both forms of throughput, the impact of the routing protocol is not apparent except as it interacts with other factors, and the factor interactions are not as extensive as for delay. Thus, for all response variables the factors cannot be studied in isolation. As well, the analysis provides a means for a system architect to determine the level to set the factors to optimize a specific service delivery metric, or combination of metrics.

Factor interaction on service delivery in mobile ad hoc networks

Location aware, dependable multicast for mobile ad hoc networks

This paper proposes a new routing protocol for ad hoc networks built around the source routing technique combined with the location (e.g., GPS coordinates) of nodes obtained by an energy and distance smart dissemination mechanism. The key new observation used is that the location information provides each node with a snapshot of the topology of the complete network from which a source route may be computed locally rather than through route discovery. The resulting protocol has reduced delay, and is more bandwidth and energy efficient, than both traditional (proactive and reactive) ad hoc routing protocols, as well as location based routing protocols.

Dynamic source routing for ad hoc networks using the global positioning system

This paper presents a network layer mechanism for the efficient dissemination of Global Positioning System (GPS) based node position in ad hoc networks, and shows its application to problems involving geographic awareness. In particular, we describe how, based on a "position database" maintained through the dissemination mechanism, a node of the network can direct messages to all the nodes currently present in a precise geographic area. The effectiveness and accuracy of the dissemination mechanism is demonstrated through the use of simulations. We show that for ad hoc networks with up to 60 nodes, the position database correctly determines which nodes are actually in the expected geographic area the 97% of the time.

Violet R. Syrotiuk

Papers

A distance routing effect algorithm for mobility (DREAM)

Factor interaction on service delivery in mobile ad hoc networks

Location aware, dependable multicast for mobile ad hoc networks

Dynamic source routing for ad hoc networks using the global positioning system

Geographic messaging in wireless ad hoc networks