Using machine-learning methods for musical style modeling

The ability to construct a musical theory from examples presents a great intellectual challenge that, if successfully met, could foster a range of new creative applications. Inspired by this challenge, we sought to apply machine-learning methods to the problem of musical style modeling. Our work so far has produced examples of musical generation and applications to a computer-aided composition system. Machine learning consists of deriving a mathematical model, such as a set of stochastic rules, from a set of musical examples. The act of musical composition involves a highly structured mental process. Although it is complex and difficult to formalize, it is clearly far from being a random activity. Our research seeks to capture some of the regularity apparent in the composition process by using statistical and information theoretic tools to analyze musical pieces. The resulting models can be used for inference and prediction and, to a certain extent, to generate new works that imitate the style of the great masters.     

Normalizing Behavior of Unsaturated Granular Pavement Materials

One of the important components of a flexible pavement structure is granular material layers. Unsaturated granular pavement materials (UGPMs) in these layers influence stresses and strains throughout the pavement structure, and have a large effect on asphalt concrete fatigue and pavement rutting (two of the primary failure mechanisms for flexible pavements). The behavior of UGPMs is dependent on water content, but this effect has been traditionally difficult to quantify using either empirical or mechanistic methods. This paper presents a practical mechanistic framework for determining the behavior of UGPMs within the range of water contents, densities, and stress states likely to be encountered under field conditions. Both soil suction and generated pore pressures are determined and compared to confinement under typical field loading conditions. The framework utilizes a simple soil suction model that has three density-independent parameters, and can be determined using conventional triaxial equipment that is available in many pavement engineering laboratories.     

A novel frequency planning algorithm for mitigating unfairness in wireless LANs

A typical objective of frequency planning in wireless networks is maximizing the overall network throughput by reducing inter-cell interference. We argue that network throughput alone, as obtained by simulations or direct measurement, is not an adequate measure for evaluating a frequency plan, so that any direct optimization of network throughput would indeed not be advisable as it is especially inadequate for fairness. Contrary to intuition, we demonstrate via simple experiments that in IEEE 802.11 wireless LANs (WLANs) a bad frequency planning, which causes higher interference, may increase the overall network throughput. Such cases occur when far users with low bit-rates get starved under bad frequency planning, while near users that use high bit-rates monopolize the transmission opportunities. Such a counter-intuitive phenomenon indicates that both network throughput and fairness must be considered for frequency planning in WLANs. In this paper we first devise a novel framework to model the load of WLAN cells considering inter-cell interference. Then, we present an efficient frequency planning algorithm which is designed on the basis of this load model. Extensive simulations show that the proposed model allows adequate evaluation of the performance of a frequency plan from both throughput and fairness perspectives. It is also shown that our algorithm provides fairer service to its users compare to existing frequency planning algorithms, while preserving high network utilization.     

Efficient handoff rerouting algorithms: a competitive on-line algorithmic approach

This paper considers the design of handoff rerouting algorithms for reducing the overall session cost in personal communication systems (PCS). Most modern communication systems that are used as an infrastructure for PCS networks are based on connection-based technologies. In these systems, the session cost is composed of two components. The setup cost represents the cost associated with the handoff operations, and the hold cost determines the expense related to the use of network resources held by the connection. This work introduces for the first time, rerouting algorithms for general graphs which are cost effective in terms of their worst-case analysis. The algorithms are analyzed using a competitive analysis approach, and it is proved that the competitive ratio of the proposed algorithms is a small constant of which the precise value depends on the ratio between the setup costs and the hold costs of the links. We also prove a lower bound of 2 on the competitive ratio of any online algorithm, which means that the proposed algorithms are close in terms of worst case behavior to the best possible rerouting algorithm. In addition, experimental results also show that the proposed algorithms indeed balance between the session setup cost and the hold cost, yielding overall lower cost when compared to other algorithms described in the literature.     

Algorithms for computing QoS paths with restoration

There is a growing interest among service providers to offer new services with Quality of Service (QoS) guarantees that are also resilient to failures. Supporting QoS connections requires the existence of a routing mechanism, that computes the QoS paths, i.e., paths that satisfy QoS constraints (e.g., delay or bandwidth). Resilience to failures, on the other hand, is achieved by providing, for each primary QoS path, a set of alternative QoS paths used upon a failure of either a link or a node. The above objectives, coupled with the need to minimize the global use of network resources, imply that the cost of both the primary path and the restoration topology should be a major consideration of the routing process. We undertake a comprehensive study of problems related to finding suitable restoration topologies for QoS paths. We consider both bottleneck QoS constraints, such as bandwidth, and additive QoS constraints, such as delay and jitter. This is the first study to provide a rigorous solution, with proven guarantees, to the combined problem of computing QoS paths with restoration. It turns out that the widely used approach of disjoint primary and restoration paths is not an optimal strategy. Hence, the proposed algorithms construct a restoration topology , i.e., a set of bridges, each bridge protecting a portion of the primary QoS path. This approach guarantees to find a restoration topology with low cost when one exists.     

Efficient location area planning for personal communication systems

A central problem in personal communication systems is to optimize bandwidth usage, while providing Quality of Service (QoS) guarantees to mobile users. Network mobility management, and in particular, location management, consumes a significant portion of bandwidth, which is a necessary overhead for supporting mobile users. We focus our efforts on minimizing this overhead. Unlike previous works, we concentrate on optimizing existing schemes, and so the algorithms we present are easily incorporated into current networks. We present the first polynomial time approximation algorithms for minimum bandwidth location management. In planar graphs, our algorithm provably generates a solution that uses no more than a constant factor more bandwidth than the optimal solution. In general graphs, our algorithm provably generates a solution that uses just a factor O (log n) more bandwidth than optimal where n is the number of base stations in the network. We show that, in practice, our algorithm produces near-optimal results and outperforms other schemes that are described in the literature. For the important case of the line graph, we present a polynomial-time optimal algorithm. Finally, we illustrate that our algorithm can also be used for optimizing the handoff mechanism.     

The use of adsorbed bromine as a brominating agent in organic reaction—the production of mono and dibromophenols

The electrochemical bromination of phenol was conducted in acid solutions on platinum and platinized titanium. The extent of substitution could be controlled by the amount of charge passed. Either mono- or di-bromophenol could be produced in high yied. Evidence is given which indicates that bromine atoms absorbed at the surface probably serve as the brominating agent. Studies in cyclic voltammetry have shown that at the initial inhibition potential, where the coverage suddenly rises, the rate of change of coverage also increases abruptly by several orders of magnitude.     

An Anchor Chain Scheme for IP Mobility Management

This work presents a simple mobility scheme for IP-based networks, termed the anchor chain scheme. The scheme combines pointer forwarding and caching methods. Every mobile host (MH) is associated with a chain of anchors that connects it to its home agent. Each anchor defines the location of the MH at a certain degree of accuracy. The accuracy is increased along the chain until the attachment point of the MH is reached. We develop distributed procedures for updating the anchor chain (binding operation) with MH movements and for delivering messages to a MH (delivery operation). In terms of worst case performance, the total cost of the binding operations is O(Move logMove), where Move is the total geographic distance that the MH has traveled since its activation. The total length of the MH's pointer path is linear with the distance between the MH and its home network, and the delivery cost is near optimal. In addition, the anchor chain of a MH is determined dynamically with no need for preliminary definitions of static anchors or regions. Our simulation results show that the anchor chain scheme also yields lower average overheads for both the binding and the delivery operations than other methods that are described in the literature, including the current home approach. We believe that the proposed scheme is scalable, fairly easy to implement and there fore attractive for supporting MHs.     

Challenges of viticulture adaptation to global change: tackling the issue from the roots

Viticulture is facing emerging challenges not only because of the effect of climate change on yield and composition of grapes, but also of a social demand for environmental‐friendly agricultural management. Adaptation to these challenges is essential to guarantee the sustainability of viticulture. The aim of this review is to present adaptation possibilities from the soil‐hidden, and often disregarded, part of the grapevine, the roots. The complexity of soil–root interactions makes necessary a comprehensive approach taking into account physiology, pathology and genetics, in order to outline strategies to improve viticulture adaptation to current and future threats. Rootstocks are the link between soil and scion in grafted crops, and they have played an essential role in viticulture since the introduction of phylloxera into Europe at the end of the 19th century. This review outlines current and future challenges that are threatening the sustainability of the wine sector and the relevant role that rootstocks can play to face these threats. We describe how rootstocks along with soil management can be exploited as an essential tool to deal with the effects of climate change and of emerging soil‐borne pests and pathogens. Moreover, we discuss the possibilities and limitations of diverse genetic strategies for rootstock breeding.     

A protocol for the calibration of gamma cameras to estimate internal contamination in emergency situations

The concern about accidents involving radioactive materials has led to the search of alternative methods to quickly identify and quantify radionuclides in workers and in the population. One of the options to face up an eventual demand for mass monitoring of internal contamination is the use of a nuclear medicine diagnostic equipment known as gamma camera, a device used to scan patients who have been administered specific amounts of radioactive materials for medical purposes. Although the gamma camera is used for image diagnosis, it can be calibrated with anthropomorphic phantoms or point sources for the quantification of radionuclide activities in the human body. This work presents a protocol for the calibration of gamma cameras for such application. In order to evaluate the suitability of this type of equipment, a gamma camera available in a public hospital located in Rio de Janeiro was calibrated for the in vivo measurement of 131I. The calibration includes the determination of detection efficiencies and minimum detectable activities for each radionuclide. The results show that the gamma camera presents enough sensitivity to detect activity levels corresponding to effective doses below 1 mSv. The protocol is the basis to establish a network of Nuclear Medicine Centres, located in public hospitals in eight countries of Latin America (Argentina, Brazil, Colombia, Cuba, Chile, Mexico, Peru and Uruguay) and in Spain that could be requested to collaborate in remediation actions in the event of an accident involving incorporation of radioactive materials. This protocol is one of the most significant outputs of the IAEA-ARCAL Project (RLA/9/049-LXXVIII) aimed to the Harmonization of Internal Dosimetry Procedures.