The minimum maximal k-partial-matching problem

In this paper, we introduce a new problem related to bipartite graphs called minimum maximal k-partial-matching (MMKPM) which has been modelled by using a relaxation of the concept of matching in a graph. The MMKPM problem can be viewed as a generalization of the classical Hitting Set and Set Cover problems. This property has been used to prove that the MMKPM problem is NPComplete. An integer linear programming formulation and a greedy algorithm have been proposed. The problem can be applied to the design process of finite state machines with input multiplexing for simplifying the complexity of multiplexers

Minimum maximum reconfiguration cost problem

This paper discusses the problem of minimizing the reconfiguration cost of some types of reconfigurable systems. A formal definition of the problem and a proof of its NP-completeness are provided. In addition, an Integer Linear Programming formulation is proposed. The proposed problem has been used for optimizing a design stage of Finite Virtual State Machines

High-Performance Architecture for Binary-Tree-Based Finite State Machines

A binary-tree-based finite state machine (BT-FSM) is a state machine with a 1-bit input signal whose state transition graph is a binary tree. BT-FSMs are useful in those application areas where searching in a binary tree is required, such as computer networks, compression, automatic control, or cryptography. This paper presents a new architecture for implementing BT-FSMs which is based on the model finite virtual state machine (FVSM). The proposed architecture has been compared with the general FVSM and conventional approaches by using both synthetic test benches and very large BT-FSMs obtained from a real application. In synthetic test benches, the average speed improvement of the proposed architecture respect to the best results of the other approaches achieves 41% (there are some cases in which the speed is more than double). In the case of the real application, the average speed improvement achieves 155%

Finite State Machines With Input Multiplexing: A Performance Study

Finite state machines with input multiplexing (FSMIMs) have been proposed in previous works as a technique for efficient mapping FSMs into ROM memory. In this paper, we propose a new architecture for implementing FSMIMs, called FSMIM with state-based input selection, whose goal is to achieve a further reduction in memory usage. This paper also describes in detail the algorithms for generating FSMIMs used by the tool FSMIM-Gen, which has been developed and made available on the Internet for free public use. A comparative study in terms of speed and area between FSMIM approaches and other field programmable gate array-based techniques is presented. The results show that the FSMIM approaches obtain huge reductions in the look-up table (LUT) usage by using a small number of embedded memory blocks. In addition, speed improvements over conventional LUT-based implementations have been obtained in many cases

The Legacy Effect of Squatter Settlements on Urban Redevelopment

The paper presents a theoretical model that seeks to answer the question of why former squatter settlements tend to upgrade/redevelop at a slower pace than otherwise similar settlements originating in the formal sector. We argue that squatter settlers’ initial strategy to access urban land creates a ‘legacy effect’ that curtails settlement upgrading possibilities even after the settlements are granted property titles. We test our model using the case of Cochabamba, Bolivia and obtain results consistent with our theoretical model prediction. Our results suggest that the commonly used ‘benign neglect while keeping the threat of eviction’ policy has profound impacts on how land is developed in the informal sector and this poses costly consequences for local governments after legalization.squatters, informal settlements, urban development, neighbourhood upgrading, urban redevelopment

Radial variations in the stellar initial mass function of early-type galaxies

The hypothesis of a universal initial mass function (IMF) -- motivated by observations in nearby stellar systems -- has been recently challenged by the discovery of a systematic variation of the IMF with the central velocity dispersion, {\sigma}, of early-type galaxies (ETGs), towards an excess of low-mass stars in high-{\sigma} galaxies. This trend has been derived so far from integrated spectra, and remains unexplained at present. To test whether such trend depends on the local properties within a galaxy, we have obtained new, extremely deep, spectroscopic data, for three nearby ETGs, two galaxies with high {\sigma} (~300 km/s), and one lower mass system, with {\sigma} ~ 100 km/s. From the analysis of IMF-sensitive spectral features, we find that the IMF depends significantly on galactocentric distance in the massive ETGs, with the enhanced fraction of low-mass stars f mostly confined to their central regions. In contrast, the low-{\sigma} galaxy does not show any significant radial gradient in the IMF, well described by a shallower distribution, relative to the innermost regions of massive galaxies, at all radii. Such a result indicates that the IMF should be regarded as a local (rather than global) property, and suggests a significant difference between the formation process of the core and the outer regions of massive ETGs.Comment: 17 pages, 13 figures. Accepted for publication in MNRA

Design strategies in facades for the reduction of housing energy consumption

This article analyzes the energy-saving potential of various facade design strategies from a life cycle perspective, including the energy needed in the use stage and the embodied energy of materials. The results provide reference data on the behaviour of these systems in Spain and make it possible to identify the best strategies for reducing energy consumption in a wide variety of potential situations that may arise in both new construction and in the rehabilitation of existing facades. The impact categories studied are fossil fuel depletion and climate change, and design strategies are linked to climate data, orientation, air change rate, facade materials and wall composition. Exchanges between the interior and exterior environments take place through the building envelope, some of whose key design parameters include lighting, ventilation and heat flux. Improving this envelope can greatly reduce environmental impact, ensuring indoor environmental quality. This analysis confirms the need to consider the interactions among the parameters studied, as it shows that there are several design solutions with similar impacts, which can be adapted to project requirements. In both new construction and rehabilitation, some of these parameters may be determined by other design decisions not necessarily aimed at reducing environmental impact, so it can be very useful to be aware of a variety of design alternatives that can be implemented in specific projects