Today's high level synthesis tools: a comparison

High-level synthesis (HLS) tools greatly reduce the effort required in Register Transfer Level (RTL) design by automatically converting behavioral algorithms into synthesizable hardware descriptions. These tools are being actively developed, and even though they have been around for more than 10 years, they have only recently been adopted by industry. As a result of the reduced designer effort, advantages of high level synthesis include an improved time to market and the possibility to do extensive design space exploration. In this work, we present a comparison of some of today's tools based on our own experience of implementing an image processing algorithm. Different features are highlighted, such as design entry, capabilities, synthesis results, verification options and the learning curve for the designer. We have found that the high-level synthesis tools greatly differ in their features and also in the types of applications they can handle. Because of design space exploration capabilities, the quality of HLS generated hardware is comparable to manual RTL design, in terms of area, latency and also power consumption. Among the tools that we have evaluated so far, the most impressive results were obtained using Catapult C from Mentor Graphics

Data reuse buffer synthesis using the polyhedral model

Current high-level synthesis (HLS) tools for the automatic design of computing hardware perform excellently for the synthesis of computation kernels, but they often do not optimize memory bandwidth. As accessing memory is a bottleneck in many algorithms, the performance of the generated circuit could benefit substantially from memory access optimization. In this paper, we present a method and a tool to automate the optimization of memory accesses to array data in HLS by introducing local memory tailored perfectly to store only the data that are used repeatedly. Our method detects data reuse in the source code of the algorithm to be implemented in hardware, selects and parameterizes data reuse buffers, and generates a register transfer level design of the data buffers and a matching loop controller that coordinates reuse buffers and datapath operations. Throughout this paper, the polyhedral representation is used extensively as it proves to be well suited for calculations on loop nests and data accesses. As a consequence, this paper is limited to affine programs which can be represented in this model. Experiments show that our method outperforms state-of-the-art academic and commercial HLS tools

An exploration of synchronization solutions for parallel short-range optical interconnect in mesochronous systems

As a result of the increasing complexity of electronic chips, the bandwidths required for inter- and intra-chip communication are rapidly increasing. As optoelectronics provides high=bandwidth and high-density interconnection it is considered as a candidate for short-range interconnection. For such interconnections, situated at a low level in the systems hierarchy, the interconnect latency is extremely critical for the systems performance. This paper describes some methods for mesochronous synchronization, needed for such interconnections. It will be shown that it can be beneficial to use an additional optical link to transfer a synchronization signal. Such a reference signal can be used efficiently for phase detection, provided that the data skew is sufficiently small, and result in a decrease of the cost-per-link

Towards a tighter integration of generated and custom-made hardware

Most of today's high-level synthesis tools offer a fixed set of interfaces to communicate with the outer world. A direct integration of custom IF in the datapath would often be more beneficial than an integration using such communication interfaces. If a certain interface protocol is not offered by the tool, either translation blocks (wrappers) are needed or the code should be written at a lower level. The former solution may hurt the performance, while the latter one is often impossible using an untimed high-level description. In this paper interface protocols or sets of JP core accesses are first described at a low level as sets of operations with scheduling information (macros). During the synthesis process, corresponding function calls are mapped to these macros. This facilitates the integration of custom-made hardware and hardware generated by high-level synthesis tools

Rules of intra-individual development in adolescence: A framework

Four longitudinal models are used to present a short review of research into adolescent psychosocial development. This review reveals adolescent development to proceed in a regular manner. This process of regular development suggests that it might be possible to uncover rules of intra-individual development. The aim of this paper is to propose a framework of such rules. The framework starts from three propositions of life-span psychology: (1) development has a direction; (2) development is multidirectional; (3) there is plasticity: within-person variability in development. The first proposition leads to the distinction between normative endpoints and transient states. The second proposition unfolds in the distinction between equifinality and multifinality and the notions of developmental neighbourhood effects, developmental continua and frequency of change. The third proposition shows changes in the prevalence of normative endpoints. Application of the framework to research into adolescent psychosocial development shows it to be useful to describe intra-individual development in a systematic manner

CLooGVHDL and JCCI

CLooGVHDL and JCCI offer an extendible C-to-VHDL framework to develop high-level synthesis techniques for data-intensive applications on heterogeneous memory systems. 1

IFC-based calculation of the Flemish Energy Performance Standard

This paper illustrates our findings concerning space based design methodologies and interoperability issues for today's Building Information Modeling (BIM) environments. A method is elaborated which enables building designers to perform an automated energy use analysis, based oil an Industry Foundation Classes (IFC) model derived from a commercial BIM environment, in this case Autodesk Revit 9.1. A prototype application was built, which evaluates the building model as well as vendor-neutral exchange mechanisms, in accordance with the Flemish Energy Performance Regulation (EPR) standard. Several issues regarding the need for space-based building models are identified and algorithms are developed to overcome possible shortcomings

Disruptive behavior disorders and psychopathic traits in adolescents:Empathy-related responses to witnessing animal distress

Cruelty to animals is a symptom of conduct disorder and associated with psychopathic traits in childhood. One of the factors thought to contribute to animal cruelty is reduced empathy and concern for the well-being of animals. A first aim of this study was to examine empathy towards animals in distress in male adolescents with disruptive behavior disorders (DBD) and high or low psychopathic traits, and normal controls (NC). Psychopathic traits were assessed by the Antisocial Process Screening Device (APSD). Respondents were exposed to a short film clip depicting a baby bear in distress. Heart rate (HR) responses were monitored during film exposure. Afterwards, respondents were asked to report the emotions they had observed and experienced. Contrary to expectations based on research on human empathy, no group differences were found in empathy-related responses to witnessing animal distress. Both DBD groups and normal controls observed equal levels of distress in the baby bear, experienced as much empathy and sympathy, and showed similar levels of HR reduction during the most dramatic scene. Results suggest that empathy for humans does not generalize to animals, and vice versa. A second aim was to examine the associations between empathy-related responses and the broad concept of psychopathy as well as its dimensions. The relationships were different and for the most part reversed in the NC and DBD groups. Group proved to be an important moderating factor, indicating that results obtained within a sample of healthy adolescents do not generalize to adolescents with DBD, and vice versa

Neighbourhood immigrant concentration effects on migrant and native youth’s educational commitments, an enquiry into personality differences

Part of the research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007–2013) / ERC Grant Agreement n. 615159 (ERC Consolidator Grant DEPRIVEDHOODS, Socio-spatial inequality, deprived neighbourhoods, and neighbourhood effects) and from the Marie Curie programme under the European Union’s Seventh Framework Programme (FP/2007–2013) / Career Integration Grant n. PCIG10-GA-2011-303728 (CIG Grant NBHCHOICE, Neighbourhood choice, neighbourhood sorting, and neighbourhood effects).In the literature examining neighbourhood effects on educational outcomes, the socialisation mechanism is usually investigated by looking at the association between neighbourhood characteristics and educational attainment. The step in between, that adolescents actually internalise educational norms held by residents, is often assumed. We attempt to fill this gap by looking at how the internalisation of educational norms (commitments) is influenced by neighbourhoods’ immigrant concentration. We investigate this process for both migrant and native youth, as both groups might be influenced differently by immigrant concentrations. To test our hypothesis we used longitudinal panel data with five waves (N = 4255), combined with between-within models which control for a large portion of potential selection bias. These models have an advantage over naïve OLS models in that they predict the effect of change in neighbourhood characteristics on change in educational commitment, and therefore offer a more dynamic approach to modelling neighbourhood effects. Our results show that living in neighbourhoods with higher proportions of immigrants increases the educational commitments of migrant youth compared to living in neighbourhoods with lower proportions. Besides, we find that adolescents with a resilient personality experience less influence of the neighbourhood context on educational commitments than do adolescents with non-resilient personalities.Publisher PDFPeer reviewe