390 research outputs found

    Design of doubly-complementary IIR digital filters using a single complex allpass filter, with multirate applications

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    It is shown that a large class of real-coefficient doubly-complementary IIR transfer function pairs can be implemented by means of a single complex allpass filter. For a real input sequence, the real part of the output sequence corresponds to the output of one of the transfer functions G(z) (for example, lowpass), whereas the imaginary part of the output sequence corresponds to its "complementary" filter H(z)(for example, highpass). The resulting implementation is structurally lossless, and hence the implementations of G(z) and H(z) have very low passband sensitivity. Numerical design examples are included, and a typical numerical example shows that the new implementation with 4 bits per multiplier is considerably better than a direct form implementation with 9 bits per multiplier. Multirate filter bank applications (quadrature mirror filtering) are outlined

    Does Supply Matter? Initial Supply Conditions and the Effectiveness of Conditional Cash Transfers for Grade Progression in Nicaragua

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    We combine administrative and survey data to examine the effect of a conditional cash transfer program on grade progression in Nicaragua from 1999–2003, putting the spotlight on initial supply side conditions and the extent to which they conditioned program effectiveness. Our principal findings are that the program had a substantial effect on grade progression and that these increased over time, even after the original intervention group stopped receiving demand-side transfers. Half of the estimated program effect on progression is accounted for by a reduction in the dropout and repetition rates of beneficiary children who were already in school when the program began. Supply side conditions were important and several of them led to heterogeneous program impacts. The program was more effective in areas with autonomous schools, suggesting flexibility at the school level better enabled schools to respond to changing demand conditions. At the same time, it was also more effective in intervention areas with poor initial supply conditions as measured by indicators of grade availability and distance to school. These were the areas with lower enrollments and grade progression before the program, and thus more room for improvement. With the analysis of child schooling in hand, we then turn to assess the “effect” of the program on school supply conditions. It is precisely in the intervention areas with poor initial school supply conditions, that the program was relatively more effective in improving school supply as measured by grade availability, number of sessions per day and number of teachers. The results suggest that initial school supply conditions do not represent insurmountable obstacles for the implementation of a conditional cash transfer program, as long as these constraints are identified at the planning stage and mechanisms put in place to deal with them during the execution stage. Our results also underscore the importance of carefully considering the integrated (demand and supply) nature of conditional-cash-transfer programs, something often overlooked in the design of these interventions and, particularly, in the impact evaluation literature.impact evaluation, conditional cash transfer, schooling, supply side

    Tree-structured complementary filter banks using all-pass sections

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    Tree-structured complementary filter banks are developed with transfer functions that are simultaneously all-pass complementary and power complementary. Using a formulation based on unitary transforms and all-pass functions, we obtain analysis and synthesis filter banks which are related through a transposition operation, such that the cascade of analysis and synthesis filter banks achieves an all-pass function. The simplest structure is obtained using a Hadamard transform, which is shown to correspond to a binary tree structure. Tree structures can be generated for a variety of other unitary transforms as well. In addition, given a tree-structured filter bank where the number of bands is a power of two, simple methods are developed to generate complementary filter banks with an arbitrary number of channels, which retain the transpose relationship between analysis and synthesis banks, and allow for any combination of bandwidths. The structural properties of the filter banks are illustrated with design examples, and multirate applications are outlined

    Data-Driven Estimation of Heavy-Truck Residual Value at the Buy-Back

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    In a context of deep transformation of the entire automotive industry, starting from pervasive and native connectivity, commercial vehicles (heavy, light, and buses) are generating and transmitting much more data than passenger cars, with a much higher expected value, motivated by the higher costs of the vehicles and their added-value related businesses, such as logistics, freight, and transportation management. This paper presents a data-driven and unsupervised methodology to provide a descriptive model assessing the residual value estimates of heavy trucks subject to buy-back. A huge amount of telematics data characterizing the actual usage of commercial vehicles is jointly analyzed with different external conditions (e.g., altimetry), affecting the truck's performance to estimate the devaluation of the vehicle at the buy-back. The proposed approach has been evaluated on a large set of real-world heavy trucks to demonstrate its effectiveness in correctly assessing the real status of wear and residual value at the end of leasing contracts, to provide a few and quantitative insights through an informative, interactive and user-friendly dashboard to make a proper decision on the next business strategies to be adopted. The proposed solution has already been deployed by a private company within its data analytics services since (1) an interpretable descriptive model of the main factors/parameters and corresponding weights affecting the residual value is provided and (2) the experimental results confirmed the promising outcomes of the proposed data-driven methodology

    Nutritional vitamin D in renal transplant patients : speculations and reality

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    Reduced levels of nutritional vitamin D are commonly observed in most chronic kidney disease (CKD) patients and particularly in patients who have received a kidney transplant (KTx). In the complex clinical scenario characterizing the recipients of a renal graft, nutritional vitamin D deficiency has been put in relation not only to the changes of mineral and bone metabolism (MBM) after KTx, but also to most of the medical complications which burden KTx patients. In fact, referring to its alleged pleiotropic (non-MBM related) activities, vitamin D has been claimed to play some role in the occurrence of cardiovascular, metabolic, immunologic, neoplastic and infectious complications commonly observed in KTx recipients. Furthermore, low nutritional vitamin D levels have also been connected with graft dysfunction occurrence and progression. In this review, we will discuss the purported and the demonstrated effects of native vitamin D deficiency/insufficiency in most of the above mentioned fields, dealing separately with the MBM-related and the pleiotropic effects

    Optimality and duality of the turbo decoder

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    Proceedings of the IEEE, 95(6): pp. 1362-1377.The near-optimal performance of the turbo decoder has been a source of intrigue among communications engineers and information theorists, given its ad hoc origins that were seemingly disconnected from optimization theory. Naturally one would inquire whether the favorable performance might be explained by characterizing the turbo decoder via some optimization criterion or performance index. Recently, two such characterizations have surfaced. One draws from statistical mechanics and aims to minimize the Bethe approximation to a free energy measure. The other characterization involves constrained likelihood estimation, a setting perhaps more familiar to communications engineers. The intent of this paper is to assemble a tutorial overview of these recent developments, and more importantly to identify the formal mathematical duality between the two viewpoints. The paper includes tutorial background material on the information geometry tools used in analyzing the turbo decoder, and the analysis accommodates both the parallel concatenation and serial concatenation schemes in a common framework

    Italian politics in an era of recession : the end of bipolarism?

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    Italian politics have undergone momentous change in the 2007–2017 decade under the impact of the eurozone crisis, whose peak in 2011–2013 could be equated to the earlier watershed years of 1992–1994. The lasting impact of the upheaval in Italian politics in the early 1990s could still be felt in the decade of economic recession, but there were also new challenges prompted by a crisis that had its roots in international financial contagion and which unravelled under the shadow of both recession and austerity. The changes were of an economic, social, cultural, institutional, policy-oriented and political nature. If one central quintessentially political theme stands out by the end of this decade it is the apparent exhaustion of the quest for bipolarisation that was initiated in the early 1990s

    Turnout and voting behaviour in constitutional referendums: a regional analysis of the Italian case

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    This paper investigates regional disparities of both turnout and voting behaviour in constitutional referendums. The analysis is undertaken at the NUTS-3 level and it considers the three constitutional referendums held in Italy in the period 2001–2016. It finds that turnout was lower in provinces with higher unemployment rates and where citizens had a stronger affiliation to opposition parties. These factors, along with level of government popularity, were important drivers of referendum results, especially in 2006 and 2016 when the referendums were rejected. In addition, while the three referendums implied different effects for rich and poor regions, mainly due to decentralization of powers, the local voting patterns did not reflect this. Overall, these findings suggest that the merit of the constitutional reforms played little part in explaining the outcome of the referendums

    Labouring women who used a birthing pool in obstetric units in Italy: prospective observational study

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    Background For women at low risk of childbirth complications, water immersion during labour is a care option in many high income countries. Our aims were (a) to describe maternal characteristics, intrapartum events, interventions, maternal and neonatal outcomes for all women who used a birthing pool during labour who either had a waterbirth or left the pool and had a landbirth, and for the subgroup of women who had a waterbirth in 19 obstetric units, and (b) to compare maternal characteristics, intrapartum events, interventions, and maternal and neonatal outcomes for women who used a birthing pool with a control group of women who did not use a birthing pool for whom we prospectively collected data in a single centre. Methods Prospective observational study in 19 Italian obstetric units 2002-2005. Participants were: (a) 2,505 women in labour using a birthing pool in 19 obstetric units; and (b) 114 women in labour using a birthing pool and 459 women who did not use a birthing pool in one obstetric unit. Descriptive statistics were calculated for the sample as a whole and, separately, for those women who gave birth in water. Categorical data were compared using Chi square statistics and continuous data by T-tests. Results Overall, 95.6% of women using a birthing pool had a spontaneous vertex delivery, 63.9% of which occurred in water. Half of nulliparas and three quarters of multiparas delivered in water. Adverse maternal and neonatal outcomes were rare. There were two cases of umbilical cord snap with waterbirth. Compared with controls, significantly more women who used a birthing pool adopted an upright birth position, had hands off delivery technique, and a physiological third stage. Significantly fewer nulliparas had an episiotomy, and more had a second degree perineal tear, with no evidence of a difference for extensive perineal tears. Conclusions Birthing pool use was associated with spontaneous vaginal birth. The increase in second degree tears was balanced by fewer episiotomies. Undue umbilical cord traction should be avoided during waterbirth
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