| Against the back-cloth of the explosive expansion of the Internet and the continued dramatic increase in demand for high-speed multimedia wireless services, there is an urging demand for exible, broadband transceivers. A versatile broadband multiple access scheme, combining frequency-hopping (FH) with multicarrier DSCDMA (FH/MC DS-CDMA) is proposed and investigated. The FH/MC DS-CDMA scheme i...

Most of existing rendezvous algorithms generate channel-hopping sequences based on the whole channel set. They are inefficient when the set of available channels is a small subset of the whole channel set. We propose a new algorithm called ZOS which uses three types of elementary sequences (namely, Zero-type, One-type, and S-type) to generate channel-hopping sequences based on the set of availa...

The one dimensional Hubbard model with nearest and (negative) next-nearest neighbour hopping has been studied with the densitymatrix renormalization group (DMRG) method. A large region of ferromagnetism has been found for finite density and finite on-site interaction. PACS : 74.25.Ha, 75.10.Lp

We show that regional differences in returns to information technology (IT) investments by US firms are attributable in part to IT spillovers generated by the flow of IT workers among firms. We use a newly developed source of employee micro-data with employer identifiers and location information to model IT workers’ mobility patterns. Access to an external IT pool that is one standard deviation...

As frequencies and feature size scale faster than operating voltages, power density is increasing in every processor generation. Along with that, leakage (highly dependent on temperature) has become an important source of power. Due to the non uniformity of on-chip power density, localized hot spots may create transient high temperature in a restricted area of the chip. These temperatures are s...

Cognitive Radios are promising solutions to the problem of overcrowed spectrum. Using channel selection techniques the access can be opportunistic by using frequency hopping, frequency tracking and frequency coding. Spectrum sharing cognitive radio networks allows cognitive radio users to share the spectrum bands of the licensed users. This paper explores various cognitive radio spectrum sharin...

Spread Spectrum (SS) has been a well-studied technique in signal processing. As a tool for watermarking in an adversarial context, however, this methodology needs caution and new variations. We suggest SS variants where the detection rule is randomized in the sense of having the watermark detector use secret coin flips to choose subsets of the watermarked data and perform correlation tests. We ...

0 0 0 Abstract-The information theoretic capacity of frequency-hop spread-spectrum multiple-access communication is considered. In order to account for independent encoding and decoding and private (to the sender and receiver) hopping patterns an interference channel model is adopted with K sender-receiver pairs with the ith receiver only interested in the message transmitted by the ith sender....

We study N = 1 supersymmetric SU(Nc) Yang-Mills theory on the lattice at strong coupling and largeNc. Our method is based on the hopping parameter expansion in terms of random walks, resummed for any value of the Wilson parameter r in the small hopping parameter region. Results are given for the mesonic (2-gluino) and fermionic (3-gluino) propagators and spectrum. PACS numbers: 11.15.Ha, 10.60....

We experimentally investigate the performance of IEEE 802.15.4 radio links and their failure modes in an office building, and, based on this study, propose an adaptation mechanism to conciliate application-level reliability requirements with the underlying network-level properties. The mechanism has two aspects: the spatially-adaptive aspect, implemented through adaptively selecting one or more...