A Survey on Performance Optimization of High-Level Synthesis Tools

Field-programmable gate arrays(FPGAs)have recently evolved as a valuable component of the heterogeneous computing.The register transfer level(RTL)design flows demand the designers to be experienced in hardware,resulting in a possible failure of time-to-market.High-level synthesis(HLS)permits designers to work at a higher level of abstraction through synthesizing high-level language programs to RTL descriptions.This provides a promising approach to solve these problems.However,the performance of HLS tools still has limitations.For example,designers remain exposed to various aspects of hardware design,development cycles are still time consuming,and the quality of results(QoR)of HLS tools is far behind that of RTL flows.In this paper,we survey the literature published since 2014 focusing on the performance optimization of HLS tools.Compared with previous work,we extend the scope of the performance of HLS tools,and present a set of three-level evaluation criteria,covering from ease of use of the HLS tools to promotion on specific metrics of QoR.We also propose performance evaluation equations for describing the relation between the performance optimization and the QoR.We find that it needs more efforts on the ease of use for efficient HLS tools.We suggest that it is better to draw an analogy between the HLS development process and the embedded system design process,and to provide more elastic HLS methodology which integrates FPGAs virtual machines.

ON THE OPTIMIZATION OF VLSI ALLOCATION IN HIGH-LEVEL SYNTHESIS

Allocation is one of main tasks in the high-level synthesis. It includes module , functional unit allocation, storage allocation and interconnection allocation. This paper models the allocation problem as cluster analysis and applies a new algorithm, neighbor state transition (NST) algorithm, for cluster optimization. It is proved that the algorithm produces an asymptotically global optimal solution with the upper bound on the cost function (1 + O(1/n)2-ε)F*, When F" is the cost of the optimum solution, n is the problem size and e is a positive parameter arbitrarily close to zero. The numerical examples show that the NST algorithm produces better results compared to the other known methods.

Synthesis of SrTiO_3 for immobilization of simulated HLW by SHS

Strontium titanate synroc samples were synthesized by self-propagating high-temperature synthesis （SHS）. Sr directly took part in the synthesis process. As a result, the loading content issue is basically resolved. The products were characterized by density, microhardness X-ray diffraction, and scanning electron microscopy （SEM/EDS）. The leaching rate was measured by the method of PCT （product consistency test）. The results indicate that the Sr^2＋-SrTiO3 compound is of high density, low leach rate and high stability and the synthesis process is feasible in technology and economy. It can be concluded that the strontium titanate synroc is a perfect material to immobilize HLW.

Synthesis of New Mannich Products Bearing Quinoline Nucleous Using Reusable Ionic Liquid and Antitubercular Evaluation

A series of Mannich products bearing quinoline nucleus was synthesized, characterized, and evaluated for their in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv. The results showed that compounds 4b, and 4d found most active with percentage inhibition of 95, and 96, respectively, at minimum inhibitory concentration (MIC) of >6.25 μg/mL, among the synthesized compounds. Whereas, compounds 4a, 4c, 4e, and 4f exhibited considerable antitubercular activity with percentage inhibition of 71, 79, 55, and 68, respectively, at MIC of >6.25 μg/mL. The structures of synthesized compounds were elucidated by various spectroscopic tools like IR, 1H NMR, 13C NMR, mass and elemental analysis.

DYNAMICS ANALYSIS OF SPECIAL STRUCTURE OF MILLING-HEAD MACHINE TOOL

The milling-head machine tool is a sophisticated and high-quality machine tool of which the spindle system is made up of special multi-element structure. Two special mechanical configurations make the cutting performance of the machine tool decline. One is the milling head spindle supported on two sets of complex bearings. The mechanical dynamic rigidity of milling head structure is researched on designed digital prototype with finite element analysis（FEA） and modal synthesis analysis （ MSA ） for identifying the weak structures. The other is the ram structure hanging on milling head. The structure is researched to get dynamic performance on cutting at different ram extending positions. The analysis results on spindle and ram are used to improve the mechanical configurations and structure in design. The machine tool is built up with modified structure and gets better dynamic rigidity than it was before.

In-situ Fabricated TiB_2 Particle-whisker Synergistically Toughened Ti(C,N)-based Ceramic Cutting Tool Material

The mechanical properties of ceramic cutting tool materials can be modified by introducing proper content of nanoparticles or whiskers.However,the process of adding whiskers or nanoparticles has the disadvantages of high cost and health hazard as well as the agglomeration;although a new in-situ two-step sintering process can solve the above problems to some extent,yet the problems of low conversion ratio of the raw materials and the abnormal grain growth exist in this process.In this paper,an in-situ one-step synthesis technology is proposed,which means the growth of whiskers or nanoparticles and the sintering of the compact can be accomplished by one time in furnace.A kind of Ti（C,N）-based ceramic cutting tool material synergistically toughened by TiB_2 particles and whiskers is fabricated with this new process.The phase compositions,relationships between microstructure and mechanical properties as well as the toughening mechanisms are analyzed by means of X-ray diffraction（XRD）and scanning electron microscopy（SEM）.The composite which is sintered under a pressure of 32 MPa at a temperature of 1700℃in vacuum holding for 60 min can get the optimal mechanical properties.Its flexural strength,fracture toughness and Vickers hardness are 540 MPa,7.81 MPa·m（1/2）and 20.42 GPa,respectively.The composite has relatively high density,and the in-situ synthesized TiB_2 whiskers have good surface integrity,which is beneficial for the improvement of the fracture toughness.It is concluded that the main toughening mechanisms of the present composite are whiskers pulling-out and crack deflection induced by whiskers,crack bridging by whiskers/particles and multi-scale particles synergistically toughening.This study proposes an in-situ one-step synthesis technology which can be well used for fabricating particles and whiskers synergistically toughened ceramic tool materials.

Robust tracking control for micro machine tools with load uncertainties

The quality of the micro-mechanical machining outcome depends significantly on the tracking performance of the miniaturized linear motor drive precision stage.The tracking behavior of a direct drive design is prone to uncertainties such as model parameter variations and disturbances.Robust optimal tracking controller design for this kind of precision stages with mass and damping ratio uncertainties was researched.The mass and damping ratio uncertainties were modeled as the structured parametric uncertainty model.An identification method for obtaining the parametric uncertainties was developed by using unbiased least square technique.The instantaneous frequency bandwidth of the external disturbance signals was analyzed by using short time Fourier transform technique.A two loop tracking control strategy that combines the μ-synthesis and the disturbance observer(DOB) techniques was proposed.The μ-synthesis technique was used to design robust optimal controllers based on structured uncertainty models.By complementing the μ controller,the DOB was applied to further improving the disturbance rejection performance.To evaluate the positioning performance of the proposed control strategy,the comparative experiments were conducted on a prototype micro milling machine among four control schemes:the proposed two-loop tracking control,the single loop μ control,the PID control and the PID with DOB control.The disturbance rejection performances,the root mean square(RMS) tracking errors and the performance robustness of different control schemes were studied.The results reveal that the proposed control scheme has the best positioning performance.It reduces the maximal errors caused by disturbance forces such as friction force by 60% and the RMS errors by 63.4% compared with the PID control.Compared to PID with DOB control,it reduces the RMS errors by 29.6%.

METHOD OF HIGH-LEVEL TECHNOLOGY MAPPING BASED ON KNOWLEDGE(RULE)

This paper studies the linkage problem between the result of high-level synthesis and back-end technology, presents a method of high-level technology mapping based on knowl edge, and studies deeply all of its important links such as knowledge representation, knowledge utility and knowledge acquisition. It includes: (1) present a kind of expanded production about knowledge of circuit structure; (2) present a VHDL-based method to acquire knowledge of tech nology mapping; (3) provide solution control strategy and algorithm of knowledge utility; (4)present a half-automatic maintenance method, which can find redundance and contradiction of knowledge base; (5) present a practical method to embed the algorithm into knowledge system to decrease complexity of knowledge base. A system has been developed and linked with three kinds of technologies, so verified the work of this paper.

基于ZYNQ的通用型卷积神经网络设计与实现

针对基于FPGA平台的神经网络开发周期过长、调节网络模型麻烦等问题,设计了一种基于ZYNQ的通用型卷积神经网络模型。首先通过Tensorflow平台搭建神经网络并训练得到模型各层权重;其次利用高层次综合工具进行卷积层和池化层的IP核设计;然后在ZYNQ平台上部署模型;最后分别运行了Le Net-5和Alex Net-8神经网络进行验证。实验结果表明模型在只损失极少准确度的情况下,卷积与池化运算速度相比于ARM平台分别提高了3.65倍和2.31倍,并具备通用性。

从41种知识综合方法中推荐系统评价类型:一项基于网络的决策支持工具——“Right Review”的介绍

知识综合方法的激增为研究者正确选择系统评价方法带来了挑战。为应对这一挑战,加拿大多伦多大学、女王大学,英国谢菲尔德大学等多家研究机构组建的研究团队研发了一项基于网络的决策支持工具“Right Review”。该工具能为用户从41种知识综合方法中推荐系统评价方法,其中定量研究系统评价26种、定性研究系统评价15种。“Right Review”工具免费开放,简单易用,能有效辅助科研工作者选择合适的系统评价方法和获取相关信息和资源。本文对该工具的核心功能进行介绍,以期为国内研究者开展系统评价提供工作辅助的提示和参考。

自蔓延高温合成法制备金刚石工具材料研究现状

金刚石工具多采用热压烧结法制备,但此方法存在能耗高、结合剂对金刚石的把持力弱、石墨模具污染环境等缺点。自蔓延高温合成法(SHS)不仅具有高效、节能的优点,而且反应过程中产生的瞬时高温有助于金刚石表面形成碳化物,能使结合剂与金刚石形成化学冶金结合。因此,SHS制备金刚石工具受到广泛关注。本文首先基于相关体系的热力学参数(绝热温度),分析了SHS制备金刚石工具的可行性;综述了原料配比、稀释剂、金刚石浓度及排布方式、引燃方式及碳化物的形成等因素对Ni-Al、Ti-Al及Fe-Al体系SHS制备金刚石工具材料的影响;然后,对比了所制得的金刚石工具材料的性能。最后,展望了SHS制备金刚石工具材料潜在的研究方向,提出了抑制SHS反应过程中金刚石石墨化的方法。

基于改进的Alexnet的服装识别及FPGA加速实现

为了快速识别服装款式类型,针对现有的服装识别网络模型有所累赘以及速度响应仍然有待提升的问题,设计了一种改进的Alexnet。采用小卷积核替换大卷积核的方式减少计算量并提升识别准确度,相比于原神经网络提升了2个百分点;然后通过对网络进行权重提取,最后在FPGA进行网络搭建,通过FPGA的高运算功能进行加速,在稍微减少改进的Alexnet准确度的情况下大幅度地提升了识别速度,相比于ARM平台提升了3倍。

癌症患者使用移动医疗工具体验的Meta整合

目的系统评价和整合癌症患者使用移动医疗工具体验的质性研究,为改善移动医疗工具技术提供依据。方法在Web of Science、PubMed、the Cochrane Library、Embase、Scopus、中国知网、中国生物医学数据库文献服务系统、万方数据库、维普数据库检索关于癌症患者使用移动医疗工具体验的质性研究,检索时限为建库至2022年2月。结果共纳入13篇研究,提炼出33个明确的研究结果,将相似的研究结果归纳形成10个新类别,最终综合得出4个整合结果:癌症患者使用移动医疗工具的益处;癌症患者使用移动医疗工具的挑战;癌症患者使用移动医疗工具的影响因素;癌症患者使用移动医疗工具的期望和偏好。结论医疗保健专业人员应该关注和了解癌症患者使用移动工具的体验,根据其意愿及反馈提升技术,丰富功能,进一步指导和规范其对移动医疗工具的使用。

金刚石粒度和含量对自蔓延高温合成NiAl结合金刚石复合材料性能的影响

以Ni粉、Al粉、金刚石为原料,采用自蔓延高温合成法制备了NiAl结合金刚石复合材料,研究了金刚石的粒度和含量对Ni-Al体系燃烧温度和燃烧波蔓延速度的影响以及对复合材料性能的影响。结果表明:金刚石降低了Ni-Al体系的燃烧温度和燃烧波蔓延速度,并提高NiAl基体的抗压强度和维氏硬度。但随着金刚石含量的增加,复合材料的力学性能有所下降,NiAl峰升高,Ni_(3)Al峰下降。随着金刚石的粒度降低,Ni-Al体系的燃烧温度先降低后升高,燃烧波蔓延速度则是先增大后减小,复合材料的抗压强度先升高后降低,维氏硬度降低,Ni_(3)Al峰先升高后降低,NiAl和Ni峰则是先降低后升高。当金刚石含量为10 mass%、粒度为150~180μm时,复合材料的综合性能最佳,体积密度为3.28 g/cm^(3),抗压强度为92.0 MPa,维氏硬度为122.06 HV,Ni3Al峰达到最高。

Dimensional Synthesis Design of Novel Parallel Machine Tool

This paper presents dimensional synthesis design theory for a novel planar 3-DOF (degrees of freedom) parallel machine tool. Closed-form solutions are developed for both the inverse and direct kinematics. The formulation of the dexterity and the definitions of the theoretical workspace and the valid workspace are used to analyze the effects of the design parameters on the dexterity and workspace. The analysis results are used to propose an approach to satisfy the platform motion requirement while realizing orientation capability, dexterity and valid workspace. A design example is given to illustrate the effectiveness of this approach.

Register Allocation Algorithm for High-Level Circuit Synthesis for Improved Testability

Register allocation in high-level circuit synthesis is important not only for reducing area, delay, and power overheads, but also for improving the testability of the synthesized circuits. This paper presents an improved register allocation algorithm that improves the testability called weighted graph-based balanced register allocation for high-level circuit synthesis. The controllability and observability of the registers and the self-loop elimination are analyzed to form a weighted conflict graph, where the weight of the edge between two nodes denotes the tendency of the two variables to share the same register. Then the modified desaturation algorithm is used to dynamically modify the weights to obtain a final balanced register allocation which improves the testability of the synthesized circuits a higher fault coverage than other algorithms with Tests on some benchmarks show that the algorithm gives less area overhead and even less time delay.

自蔓延高温合成NiAl基金刚石工具材料的热力学研究

计算了Ni-Al体系及Ni-Al-金刚石体系自蔓延高温合成NiAl金属间化合物的绝热温度,运用物质自由能函数理论,对主要反应进行了热力学计算,结合相图预测了自蔓延高温合成产物,并用自蔓延高温合成实验结果与预测结果进行对比,分析了自蔓延高温合成NiAl金属间化合物的物相生成过程。结果表明:4Ni-2Al反应的驱动力比Ni-Al体系的大,4Ni-2Al体系绝热温度为1816 K,可实现燃烧波自维持,根据相图预测产物是NiAl和Ni_(3)Al,确定最佳的Ni-Al体系配比为4Ni-2Al。4Ni-2Ali-10%(质量分数)金刚石体系与4Ni-2Al-15%(质量分数)金刚石体系的绝热温度分别为1709 K和1655 K,均可实现燃烧波自维持,自蔓延高温合成产物均为NiAl、Ni_(3)Al及部分Ni。热力学分析结果与XRD、FESEM及EDS能谱分析结果是吻合的。

政策工具视角下我国深度合成治理政策研究——基于30份政策文本的扎根分析

深度合成已成为当今人工智能领域的重要分支和技术趋势。采用NVivo12软件对我国30份深度合成治理政策文本进行词频编码分析,研究发现:在深度合成治理政策体系中,引导型、赋能型、治理型和强制型政策工具相互协作、补充,共同构建一个综合高效的框架。然而,当前我国深度合成治理仍面临一系列挑战,包括安全标准不够健全、技术支撑力度不足、制度供给有限等问题。为了应对这些挑战,未来应采取以下关键举措:首先,制定更加完备的安全标准,填补赋能型政策工具的标准体系。包括统一深度合成技术安全属性的度量标准,强化深度合成关键环节的标准制定,并积极推动安全标准的试点实践和前瞻性研究。其次,积极推进技术建设,增强治理型政策工具的技术支持。通过深度整合多种技术,建立可信的标识体系,优化技术研发环境来实现。最后,扩充制度供给,丰富强制型政策工具的监管方式。试行监管沙盒机制和探索建立算法可信制度是其中的关键步骤。通过综合实施以上举措,有效解决深度合成治理中的核心问题,确保该技术领域的可持续发展和安全性,进而维护社会的稳定和用户的权益。

The RTL Binding and Mapping Approach of VHDL High-Level Synthesis System HLS/BIT

This paper describes a VHDL high-level synthesis system HLS/BIT with emphasis on its register-transfer level (RTL) binding and technology mapping subsystem. In more detail, the component instantiation mechanism and the knowledge-driven approach to RTL technology mapping are also presented.