Lot Of Content Research Articles

Wireless Adaptive Framed Pseudo-Bayesian Aloha (AFPBA) Algorithm with Priorities

In this paper, we propose a new priority algorithm to control the access to the wireless ATM MAC uplink frame, for multimedia traffic like wireless ATM, similar to the Pseudo-Bayesian algorithm presented in [1]. The adaptive framed Pseudo-Bayesian Aloha (AFPBA) algorithm ensures minimum access delay for high priority traffic classes with small delay degradation to low priority traffic classes. Control packets are transmitted in each slot according to transmission probabilities based on the history of the channel and in contention with other packets of the same priority class. The number of contention slots assigned for each priority class, on a given frame, changes adaptively according to its priority index and the estimated arrival rate on each frame using an adaptive slot assignment mechanism. Finally, the throughput analysis of the algorithm is presented and the delay performance is evaluated by simulation on a wireless channel in the presence of shadowing, Rayleigh fading and capture. Results show that the wireless channel offers significant delay improvements to all priority packets, especially in the presence of fast fading.

Free access stack algorithms for microcellular radio systems

We evaluate the data traffic performance of a centralized packet access protocol for microcellular radio systems supporting both speech and data users. A time-slotted radio channel is assumed. Speech contention is decoupled from data contention to give speech priority over data. A free access stack algorithm is used for handling data contention. An out-slot access scheme is used in which the slots are divided into user-information transmission slots and contention slots for sending transmission requests. The contention slots are subdivided in minislots to improve the access capacity. The out-slot algorithm performances are compared with the performances of a previously proposed in-slot one in which all slots can be used for sending user information. A memoryless channel, with capture and errors, is considered. The effects of speech traffic on data performance are evaluated. Moreover, the paper presents a method for evaluating the packet error probability of a packet cellular system. This method is used for evaluating the proposed algorithm in a microcellular system. An access technique with coordinated operation among cochannel cells is studied. The effects of sectorization on data performances and protocol unfairness are investigated. Different frequency reuse factors are taken into consideration.

Ms START: A random access algorithm for the IEEE 802.14 HFC network

In this paper we introduce the n-ary Multi-slot Stack Random Access Algorithm (msSTART) for use in an IEEE 802.14 hybrid fiber/coaxial (HFC) network. The msSTART random access algorithm (RAA) is an evolution of the stack-based START algorithm. It is an easy to implement, high-efficiency, free-access, robust, stable RAA optimized to operate in an environment where contention slots could dynamically change. Through a series of simulation studies, we demonstrate the performance advantages of msSTART by comparing its throughput/delay characteristics to those of other popular RAAs, including ALOHA and tree-search RAAs. For the latter RAAs, we also provide a unified stack representation of their operation.

Episodes of Anti-Quintilianism in the Italian Renaissance: Quarrels on the Orator as a Vir Bonus and Rhetoric as the Scientia Bene Dicendi

talian Ranaissanca humanists were a contentions lot. They quarralad among themselves. They assailed politicians, philosophers, and clerics. They even turned on the ancients. Valla attacked Aristotle; George of Trebizond, Plato. Antonio da Rho did not spare a Church Father in his Dialogus in Lactantium. But one current of criticism has not received sufficient attention. I mean the strain of anti-Quintili anism which one can document from the early Quattrocento to tha close of the Renais­ sance in Italy. The history of Quintilian in the Renaissance waits to be written. It will bave to cover a large array of topics, ranging from broad issues in padagogy to arcane rhetorical precepts such as the status doctrine; and it will bave to take into account cul­ tural developments in ail of Europe and avan the Americas. My goal in this paper is much mora humble. I wish to call attention to reactions in Renaissance Italy to two specifie points of Quin­ tilian's teachings, namely, his definitions of rhatoric and of the orator.