Efficient hardware implementation of Ray Tracing based on an embedded software for intersection computation

Parallel implementations of Ray Tracing have been enabling real time performance, as the algorithm is embarrassingly parallel. However, in order to achieve both interactivity and real time performance, the algorithm should run at a high frame rates, i.e. at least 60 frames per second. Thus, a custom parallel design in hardware is likely to achieve high rendering performance. In this paper, we improve the GridRT architecture presented in previous work. GridRT is capable of dealing with the main desirable features of Ray Tracing, such as shadows and reflection effects, imposing low area cost and a promising rendering performance. As to this work, an application-specific instruction has been added and the underlaying computation embedded into the processor’s microprogram in order to calculate the ray–triangle intersection computations. These computations are performed in pipeline, whenever possible, yielding to a considerable reduction in terms of cycles per intersection test. The presented architecture is based on the uniform grid acceleration structure. It allows for a massive twofold parallelism: parallel ray–triangle intersection tests as well as parallel processing of many rays. A hardware implementation of the improved architecture is presented, together with the corresponding performance results and resources requirements. The rendering time is reduced by 80% using a grid configuration of eight processing elements and each intersection computation time is reduced by 50% with respect to the original GridRT implementation.     

Component behavior-based adaptation in embedded software

Several models of computation have been used in software development approaches. The specialization of the existing models makes them suitable to specific application domains. Nevertheless, when there is no solution for applications at hand, heterogeneous models have been used. Within this context, this paper discusses a heterogeneous model called extended dataflow with a focus on component-based design. The emphasis lies on the dynamics of the components, including the way they interact with each other, their behavioral modeling, and flow of control. The main objective is to provide mechanisms for supporting both the ability of the run-time environment to safely dispatch tasks and the ability of components to adapt their interfaces. This paper focuses on embedded software. The purpose of the mechanisms we have been working on is to improve robustness while promoting component-based design. An adaptive application involving digital filters is used to illustrate our approach.     

嵌入式附网刻录系统的设计与实现

设计并实现了一个基于虚拟本机刻录的嵌入式附网DVD刻录系统。详细介绍了这个系统的整体设计方案，着重介绍了基于“生产者和消费者”模型的三级缓冲结构和缓冲区管理策略，并进行了相应的实验测试和性能分析。     

Successfully outsourcing embedded software development

A large US company, UIC successfully outsources embedded software development after applying people- and project-focused practices developed from a prior failed attempt. In this article the author describes 10 practices that have helped UIC create an offshore development strategy that produces embedded software at a lower cost while maintaining quality. These lessons show how both the people involved in offshore projects and the projects themselves must be treated differently from internally developed projects. Even with the high complexities and intellectual property concerns surrounding embedded software development, UIC has used these practices to establish processes that ensure successful delivery and protection of UIC's intellectual property.     

Practical verification of embedded software

Using a new verification algorithm called the compositional backward technique, the authors demonstrate that they can exhaustively verify even the largest industrial applications-comprising more than 1,000 components-in a few minutes on a standard PC     

Exceptions and interrupts in CSP

Preemptive commands to handle asynchronous exceptions and interrupts are proposed for CSP. The semantics are defined within Hoare's process model for CSP [4]. The model is then extended for process execution resulting in operational semantics that accommodate the necessary expression of process priority.     

嵌入式软件测试工程化研究与实践

随着嵌入式系统在各行各业应用的迅速发展,其核心控制软件也变得日益庞大和复杂,实行有效的嵌入式软件测试显得越来越重要.首先分析了嵌入式软件的特点及嵌入式软件测试的重要性,接着阐述了一种有效的嵌入式软件测试工程化方法,并结合一个实际测试项目验证了该方法的有效性.     

嵌入式软件形式化建模方法

随着嵌入式系统在各行各业的普及,嵌入式系统也越来越复杂,为保证嵌入式系统正确性,研究从需求分析、系统设计到系统验证、代码自动生成统一建模方法尤为重要。针对以上问题,提出采用状态变迁矩阵（STM）对嵌入式软件进行建模,通过确认STM中的每个单元格保证软件的正确性,且在需求分析阶段更容易发现需求遗漏。针对单元格处理经常出现大量的逻辑判断问题,提出采用决策表（DT）模型对复杂多条件判断分支问题进行建模。在模型建立后进行验证,最后自动生成代码。通过对紧急制动控制建模实验,说明方法的正确性。     

Architecture for embedded open software ecosystems

Software is prevalent in embedded products and may be critical for the success of the products, but manufacturers may view software as a necessary evil rather than as a key strategic opportunity and business differentiator. One of the reasons for this can be extensive supplier and subcontractor relationships and the cost, effort or unpredictability of the deliverables from the subcontractors are experienced as a major problem.The paper proposes open software ecosystem as an alternative approach to develop software for embedded systems, and elaborates on the necessary quality attributes of an embedded platform underlying such an ecosystem. The paper then defines a reference architecture consisting of 17 key decisions together with four architectural patterns, and provides the rationale why they are essential for an open software ecosystem platform for embedded systems in general and automotive systems in particular.The reference architecture is validated through a prototypical platform implementation in an industrial setting, providing a deeper understanding of how the architecture could be realised in the automotive domain.Four potential existing platforms, all targeted at the embedded domain (Android, OKL4, AUTOSAR and Robocop), are evaluated against the identified quality attributes to see how they could serve as a basis for an open software ecosystem platform with the conclusion that while none of them is a perfect fit they all have fundamental mechanisms necessary for an open software ecosystem approach.     

Composing domain-specific physical models with general-purpose software modules in embedded control software

A considerable portion of software systems today are adopted in the embedded control domain. Embedded control software deals with controlling a physical system, and as such models of physical characteristics become part of the embedded control software. In current practices, usually general-purpose languages (GPL), such as C/C++ are used for embedded systems development. Although a GPL is suitable for expressing general-purpose computation, it falls short in expressing the models of physical characteristics as desired. This reduces not only the readability of the code but also hampers reuse due to the lack of dedicated abstractions and composition operators. Moreover, domain-specific static and dynamic checks may not be applied effectively. There exist domain-specific modeling languages (DSML) and tools to specify models of physical characteristics. Although they are commonly used for simulation and documentation of physical systems, they are often not used to implement embedded control software. This is due to the fact that these DSMLs are not suitable to express the general-purpose computation and they cannot be easily composed with other software modules that are implemented in GPL. This paper presents a novel approach to combine a DSML to model physical characteristics and a GPL to implement general-purpose computation. The composition filters model is used to compose models specified in the DSML with modules specified in the GPL at the abstraction level of both languages. As such, this approach combines the benefits of using a DSML to model physical characteristics with the freedom of a GPL to implement general-purpose computation. The approach is illustrated using two industrial case studies from the printing systems domain.     

Modality and interrupts

We suggest that modal operators, in addition to their well-understood semantic role in declarative systems, also mark points at which these systems can be interrupted. We use this idea to describe an interruptible declarative system that gradually refines its responses to queries. Although initial responses may be in error, a correct answer will be provided if arbitrarily large computational resources are available. The ideas presented generalize existing work on stratification of logic programs and the treatment of floundered subgoals.     

What's ahead for embedded software?

Once deemed too small and retro for research, embedded software has grown complex and pervasive enough to attract the attention of computer scientists. There are many research questions, but most center around one issue: how to reconcile a set of domain-specific requirements with the demands of interaction in the physical world. How do you adapt software abstractions designed merely to transform data to meet requirements like real-time constraints, concurrency, and stringent safety considerations? The answer to this question has given rise to some promising research angles, including novel ways to deal with concurrency and real time and methods for augmenting component interfaces to promote safety and adaptability     

一种基于场景的嵌入式软件设计方法

UML顺序图是一种常用的在软件开发早期阶段用来描述系统基于场景的需求规约的一种可视化建模语言。通过在UML顺序图中加入带时间区间标志的时间约束,得到时间顺序图模板TSDT（Timed Sequence Diagram Template）,用来建立嵌入式软件基于场景的需求规约模型。对消息传递自动机进行实时扩展,得到时间消息传递自动机TMPA（Timed Message Passing Automata）,TMPA以自动机的形式刻画了所建立的需求规约模型,为在需求阶段验证所建立的模型是否满足用户需求奠定了基础。     

基于ARM的嵌入式数据录取设备研制

某型装备文件记录设备的信息化改造过程中,采用FPGA+ARM的框架体系和软硬件一体化设计思想,开发嵌入式处理平台,实现了多装备输出数据的实时可靠录取、传输和存储,有效解决了原设备存在的接口信号时序逻辑复杂、畸变失真严重、数据易丢失及联机功能检查等问题。 实装测试和使用情况表明,研制的嵌入式系统达到了设计要求。     

面向众测的GUI软件操作序列记录方法

由于众测人员测试水平层次不齐,导致测试步骤不统一、冗余操作过多,因此无法直接利用众测人员的操作序列生成测试用例.通过对现有测试过程研究进行分析,提出一种适用于众测场景的GUI软件的操作序列记录方法.通过基于图像与坐标信息的方法获取众测人员的操作信息,采用图像聚类划分操作信息和时间划分方法优化聚类结果,以时间先后将操作信...     

嵌入式Web服务器软件的设计和实现

针对当前嵌入式Internet技术已成为嵌入式系统发展的新技术热点的情况，讨论了嵌入式设备接入Internet的方法，论述了实现嵌入式Web服务器的关键技术——HTTP协议和通用网关接口CGI，阐述了嵌入式Web服务器的特点及其设计思想，最后提出并在VxWorks实时操作系统环境下实现了的一种嵌入式Web服务器的方案，并给出了该嵌入式Web服务器的数据处理流程以及其主要模块和功能说明。     

一种嵌入式视频记录系统的设计与实现

文章介绍了基于嵌入式控制模块DIMM-PC/520IU和专用视频处理芯片SZ1510硬件平台的MPEG-1视频记录系统的设计和实现,讨论了总体原理和架构,阐述了核心硬件模块的设计和视频记录系统的软件设计.     

激光雷达SCADA跨平台嵌入式软件设计

为满足激光雷达系统控制与数据采集( SCADA)对跨平台的需求,利用基于组件的框架技术,在ColdFire+ μC/OSII初始平台上采用标准C语言实现了SCADA嵌入式软件.在领域分析基础上明确了SCADA软件架构,对软件架构进行可通用部分和平台依赖部分划分及组件化处理,形成SCADA软件框架,并在框架基础上完成软件设计.实验结果表明,基于框架的SCADA嵌入式软件不仅提高了软件的可靠性和可扩展性,而且实现了软件向其它平台扩展的能力,达到了设计重用和代码重用目的.