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CoLoRaDe: A Novel Algorithm for Controlling Long-Range Dependent Network Traffic
Get PDFLong-range dependence characteristics have been observed in many natural or physical phenomena. In particular, a significant impact on data network performance has been shown in several papers. Congested Internet situations, where TCP/IP buffers start to fill, show long-range dependent (LRD) self-similar chaotic behaviour. The exponential growth of the number of servers, as well as the number of users, causes the performance of the Internet to be problematic since the LRD traffic has a significant impact on the buffer requirements. The Internet is a large-scale, wide-area network for which the importance of measurement and analysis of traffic is vital. The intensity of the long-range dependence (LRD) of communications network traffic can be measured using the Hurst parameter. A variety of techniques (such as R/S analysis, aggregated variance-time analysis, periodogram analysis, Whittle estimator, Higuchi's method, wavelet-based estimator, absolute moment method, etc.) exist for estimating Hurst exponent but the accuracy of the estimation is still a complicated and controversial issue. Earlier research (Rezaul et al., 2006) introduced a novel estimator called the Hurst exponent from the autocorrelation function (HEAF) and it was shown why lag 2 in HEAF (i.e. HEAF (2)) is considered when estimating LRD of network traffic. HEAF estimates H by a process which is simple, quick and reliable. In this research we extend these concepts by introducing a novel algorithm for controlling the long-range dependence of network traffic, named CoLoRaDe which is shown to reduce the LRD of packet sequences at the router buffer
Assistive Human-Machine Interfaces for Smart Homes
Get PDFComputer systems have shown in the past (Zajicek, 2000) that they can be powerful allies in home-based health care and offer great potential to improve quality of life - but only if they are designed to take into consideration the specific needs of their beneficiaries. Satisfying usability as well as the functional requirements in such a home setting are equally critical. This paper discusses the development of user interfaces, following the “Designfor- all” philosophy, oriented towards a multi-agent system interacting with an intelligent engine. Originally, the system will focus on the control of white goods (large kitchen appliances) but will have scalability properties making it appropriate and extensible for the inclusion of other devices that may be deployed thereafter. The interfaces must be flexible enough to adapt to the targeted public, fit any user’s preferences and/or needs and make the interaction as simple and intuitive as possible. This work is part of the EU FP6 IST e-inclusion ‘EASY LINE+’ project
Understanding and engaging with problematic substance use
No full textThis chapter will introduce the reader to the complex issue of substance use. The term substance use rather than drug use includes all legal substances such as alcohol, tobacco, prescribed substances such as benzodiazepines and anti-depressants, solvents such as aerosols and glue, and the more commonly known illicit substances such as crack cocaine, heroin and cannabis. The knowledge and value base underpinning policy and practice in this area is not without with confusion, conflict and contradiction. These tensions will be highlighted throughout the chapter. In keeping with the focus of the book on addressing offending the primary focus of the chapter will be to examine substance use which is more commonly associated with legal consequences to the individual and or others. The chapter will explore the changing patterns of substance use over recent decades, types of substance use, the legal context, the nature of ‘addiction’, the links with crime, before finally exploring what can be done to help problem substance users
From folk culture to modern British
Get PDFA Folk Art revival is quietly inspiring artists and illustrators, but as De s McCannon discovers, Folk Art means more than drawing owls or men with beards. It has nothing to do with extreme right wing politics. The illustrators currently inspired by Folk Art are not only reshaping their idea of illustration, they are rethinking ideas of natio
NMR of Organomagnesium Compounds
No full textSince their discovery, the exact solution composition of Grignard compounds has been
the subject of considerable debate, and given the power of NMR in elucidating chemical
structure it is unsurprising that it was applied to the study of Grignard and other organomagnesium compounds from its earliest days. However, the complex nature of the solution behaviour of such compounds and the low magnetic field strengths then available often frustrated proper analysis of the data, and the first reported NMR studies were generally inconclusive. Worse, the interpretation of early NMR spectra was often based on preconceived (and as it is now realized incorrect) notions as to the nature of the compounds in solution, so caution must be exercised when considering much of the pre-1970’s data.
Although the advent of higher field NMR instruments and our increasing understanding
of the solution behaviour of organomagnesium reagents have greatly improved the veracity
of NMR studies, detailed NMR reports on such compounds remain relatively sparse. The bulk of the literature that has been published was done so prior to the 1980’s. The reasons
for the paucity of reported NMR studies are probably three-fold: (i) organomagnesium
reagents are generally highly sensitive, making the isolation of sufficiently pure samples
problematic; (ii) different preparations can apparently give quite different NMR spectra;
(iii) the exact solution behaviour depends on a number of factors, making it difficult to
draw any general conclusions.
This paper reviews the current state of the literature on the NMR of Grignard and other organomagnesium compounds
2,6-Bis(diphenylphosphinosulfide)pyridine (L) as a facial terdentate ligand: synthesis and characterisation of the tricarbonylrhenium(I) complexes fac-[Re(CO)₃L]⁺ [Re₂(CO)₆(µ-X)₃]⁻ (X = Cl, Br or I) and fac-[Re(CO)₃L]⁺[SbF₆]⁻.
Get PDFThe halogenopentacarbonylrhenium(I) compounds react with 2,6-bis(diphenylphosphinosulfide) pyridine (L) under mild conditions to yield ionic complexes of general formulae, fac-[Re₂(CO)₃L]⁺ [Re2(CO) ₆(μ-X) )₃]⁻ (X=Cl, Br or I), in which the ligand adopts a facial terdentate bonding mode. A synthesis of [Re(CO)₃L]⁺ [SbF₆]⁻ was carried out to establish the presence of the cation, fac-[Re(CO)₃L]⁺, in the complexes. The character of the anions was confirmed by negative ion MALDI-TOF mass spectrometry. The cation is fluxional; the P–phenyl rings oriented towards the metal moiety exhibit restricted rotation at low temperature. The free energy of activation, ΔG †, for hindered rotation is ca. 47 kJ mol⁻¹ for all complexes. Solid-state₃ ¹P NMR data are reported for the free ligand and for the complexes, [Re(CO)₃L][SbF₆] and [Re(CO)₃L][Re₂(CO)₆(μ-X)₃] (X=Cl, Br or I)
Formation of dimethylamine complexes of trimethylplatinum(IV) from reactions with N,N,N’,N’-tetramethyldiaminomethane
No full textAttempts to prepare complexes of trimethylplatinum(IV) with N,N,N′N′-tetramethyldiaminomethane (TMDM) as either a chelating or bridging ligand gave only the complexes of dimethylamine [PtMe₃X(HNMe₂))]₂(X = Cl, Br and I ; 1–3 and [PtMe₃((2,2′-bipyridyil) (HNMe₂))]⁺[[BF₄]]⁺ (4)). ¹HH NMR evidence showed that only one of the two possible isomers was formed for 1–3
A Naturalistic Approach to Training Accurate and Coherent Decision Making in Rugby Union Referees
Get PDFThe purpose of this investigation was to pilot the use of a video-based training program designed to develop referees’ shared mental models. A group of English Rugby Football Union (RFU) national referees, divided into a control group (n = 15) and experimental group (n = 41) made their immediate decisions on pre and posttests of 10 video recordings taken from real game scenarios. Over a six-week period the experimental group studied training tapes consisting of 5 sets of 5 tackles, in each case with an expert providing his interpretation of the correct decision. Each clip was filmed from the referee’s perspective and taken from real game situations in order to maintain high ecological validity in accordance with naturalistic decision-making theory. The lowest ranked referees on the national panel significantly improved their percentage of correct decisions, becoming 17.43% more accurate in their decisions at the posttest. These results suggest that such shared mental model training is an appropriate method for improving referee decision making. \bb\164 words
Traffic Modelling and Simulation Techniques for Evaluating ACL Implementation
Get PDFThis paper presents a modelling and simulation framework for analysing Access Control List (ACL) implementation on Internet devices. It uses the established modelling/simulation techniques of abstraction and simplification to isolate the essential components of the system from peripheral issues. As a case study, the viability of a simple real-time optimisation technique is demonstrated
A Microgenetic Study of the Tutoring Process: Learning Centre Research
Get PDFThere is no abstract for this wor