Improvement of borrowing channel assignment for patterned traffic load by online cellular probabilistic self-organizing map

This paper describes an improvement of borrowing channel assignment (BCA) for patterned traffic load by using the short-term traffic prediction ability of cellular probabilistic self-organizing map (CPSOM). The fast growing cellular mobile systems demand more efficient and faster channel allocation techniques today. In case of patterned traffic load, the traditional BCA methods are not efficient to further enhance the performance because heavy-traffic cells cannot borrow channels from their neighboring cells with light or medium traffic that may have unused nominal channels. The performance can be increased if the short-term traffic load can be predicted. The predicted results can then be used for channel re-assignment. Therefore, the unused nominal channels of the light-or-medium-traffic cells can be transferred to the heavy-traffic cells that need more nominal channels. In this paper, CPSOM is used online for traffic prediction. In this sense, the proposed CPSOM-based BCA method is able to enhance the performance for patterned traffic load compared with the traditional BCA methods. Simulation results corroborate that the proposed method enables the system to work with better performance for patterned traffic load than the traditional BCA methods.     

Multimedia-MAC protocol: its performance analysis and applications for WDM networks

The design of the medium-access control (MAC) protocol is the most crucial aspect for high-speed and high-performance local and metropolitan area networks, since the decisions made at this level determine the major functional characteristics of these networks. Most of the MAC protocols proposed in the literature are not suitable for multimedia applications, since they have been designed with one generic traffic type in mind. As a result, they perform quite well for the traffic types they have been designed for, but poorly for other traffic streams with different characteristics. In this paper, we propose an integrated MAC protocol called the Multimedia-MAC (M-MAC), which integrates different MAC protocols into a hybrid protocol in a shared-medium network to efficiently accommodate various types of multimedia traffic streams with different characteristics and quality-of-service demands, namely, a constant-bit-rate traffic, bursty traffic (say, variable-bit-rate traffic), and emergency messages (say, control messages). We have developed a mathematical framework for the analysis and performance evaluation of our M-MAC protocol, which involves a queueing system with vacation. We have applied our M-MAC design approach to a wavelength-division multiplexing network, and evaluated its performance under various traffic conditions.     

Successful innominate thromboembolectomy of a paradoxic embolus

A 54 year-old man had symptoms of acute right hemispheric cerebral ischemia. He was initially considered for participation in a trial of early thrombolysis in stroke, but an innominate artery embolus was found with no apparent arterial source. The embolus was removed by means of a combined brachial and carotid bifurcation approach to protect the cerebral vasculature from embolic fragmentation during extraction. Further investigation revealed deep venous thrombosis, evidence of pulmonary emboli, and a patent foramen ovale, supporting a diagnosis of paradoxic embolus. Additional treatment included anticoagulation and placement of an inferior vena caval filter. The unusual condition of paradoxic embolus is reviewed, and the management of this patient is discussed.     

The Effects of Transmitter/Receiver Clock Time-Base Instability on Coherent Communication System Performance

The purpose of this paper is to present a model and associated analysis of the deleterious effects which both transmitter and receiver data clock time-base instability have on bit-error probability. The types of time-base instability modeled and analyzed include what is commonly referred to as bit jitter (epoch jitter), bit-jitter rate (time interval jitter), and data asymmetry. The biterror probability is determined as a function of the statistical characteristics of the time-base instability, the data-transition density, the signal-to-noise ratio in the bit-rate bandwidth and the mechanizations of both the data-bit detector and bit synchronizer. The latter is manifested through the bit synchronizer's natural frequency and loop-damping parameters. Numerical results which indicate the sensitivity of the system bit-error rate to various parameters of the model are provided.     

Ethnic origin, belief, and personality information in interpersonal attraction.

To test the effects on interpersonal attraction of 3 categories of information, 78 English-speaking undergraduates made liking and social distance ratings about a derived target. The person rated was either English or French Canadian, pro- or anti-capital-punishment and the harsh treatment of criminals, and high or low on the Cognitive Structure and Order scales of the Personality Research Form. Results show that the judges were all anti-capital-punishment and low on the personality traits. Belief and belief-congruence were the primary determinants of attraction. The 3 categories of information interacted on 2 measures. French Canadians were rated more favorably than English-Canadians when similar to the judge in belief or personality but less favorably when similar in neither belief nor personality. (French summary) (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The characterization and functional reliability of 45 Mbit/s optical transmitters containing MBE-grown lasers

We have characterized the performance and studied the functional reliability of 45 Mbit/s lightwave transmitters containing proton-bombarded stripe lasers grown in a research environment by molecular beam epitaxy (MBE). We observe that these transmitters have superior performance compared to transmitters containing lasers of similar geometry grown in production facilities by liquid phase epitaxy (LPE), and subsequently processed using the same technology. The reliability data of over 10 000 h indicate that the functional lifetime of the MBE lasers will be limited ultimately by extinction ratio degradation in our circuit strategy. The origin of the degradation is the increase of the spontaneous light at the bias current.     

Guided Genetic Algorithm and its Application to Radio Link Frequency Assignment Problems

The Guided Genetic Algorithm (GCA) is a hybrid of Genetic Algorithm and Guided Local Search, a meta–heuristic search algorithm. As the search progresses, GGA modifies both the fitness function and fitness template of candidate solutions based on feedback from constraints. The fitness template is then used to bias crossover and mutation. The Radio Link Frequency Assignment Problem (RLFAP) is a class of problem that has practical relevance to both military and civil applications. In this paper, we show how GGA can be applied to the RLFAP. We focus on an abstraction of a real life military application that involves the assigning of frequencies to radio links. GGA was tested on a set of eleven benchmark problems provided by the French military. This set of problems has been studied intensively by a number of prominent groups in Europe. It covers a variety of needs in military applications, including the satisfaction of constraints, finding optimal solutions that satisfy all the constraints and optimization of some objective functions whenever no solution exist (partial constraint satisfaction). Not only do these benchmark problems vary in problem nature, they are reasonably large for military applications (up to 916 variables, and up to 5548 constraints). This makes them a serious challenge to the generality, reliability as well as efficiency of algorithms. We show in this paper that GGA is capable of producing excellent results reliably in the whole set of benchmark problems.     

Ellipsoidal support vector clustering for functional MRI analysis

As an exploratory approach, the clustering of fMRI time series has proved its effectiveness in analyzing the functional MRI, especially in the detection of activated regions. Due to the arbitrary distribution of fMRI time series in the temporal domain, imposing simple assumption on the data structure usually could be misleading and limit the detector's performance. Therefore, a true data-driven clustering algorithm that adapts to the data structure is preferred, and only high-level control over the clustering procedure is desired. Support vector clustering (SVC) is a suitable one in some extent because of its advantages, such as no cluster shape restriction, no need to explicitly specify the number of clusters, and the mechanism in outlier elimination. In this work, we propose an extension of the SVC to step further toward a data-sensitive detector. This approach is named as ellipsoidal support vector clustering (ESVC). To be robust to noise, the clustering is performed on features extracted from the fMRI time series via Fourier transform. Experimental results on simulated and real data sets demonstrate the effectiveness of incorporating data structure in clustering fMRI time series.