Debugging mixed‐environment programs with Blink

Programmers build large‐scale systems with multiple languages to leverage legacy code and languages best suited to their problems. For instance, the same program may use Java for ease of programming and C to interface with the operating system. These programs pose significant debugging challenges, because programmers need to understand and control code across languages, which often execute in different environments. Unfortunately, traditional multilingual debuggers require a single execution environment. This paper presents a novel composition approach to building portable mixed‐environment debuggers, in which an intermediate agent interposes on language transitions, controlling and reusing single‐environment debuggers. We implement debugger composition in Blink, a debugger for Java, C, and the Jeannie programming language. We show that Blink is (i) simple: it requires modest amounts of new code; (ii) portable: it supports multiple Java virtual machines, C compilers, operating systems, and component debuggers; and (iii) powerful: composition eases debugging, while supporting new mixed‐language expression evaluation and Java native interface bug diagnostics. To demonstrate the generality of interposition, we build prototypes and demonstrate debugger language transitions with C for five of six other languages (Caml, Common Lisp, C#, Perl 5, Python, and Ruby) without modifications to their debuggers. Using real‐world case studies, we show that diagnosing language interface errors require prior single‐environment debuggers to restart execution multiple times, whereas Blink directly diagnoses them with one execution. Copyright © 2014 John Wiley & Sons, Ltd.     

Research Partners,Teaching Partners: A Collaboration between FYC Faculty and Librarians to Study Students’ Research and Writing Habits

In Spring 2012, instruction librarians collaborated with first year composition (FYC) faculty to study students’ research habits as they related to writing. We collected process narratives from students in the introductory FYC course at the beginning and end of the fall semester, and a group of librarians and FYC faculty coded them together. Although we did not achieve one of our initial research goals, we still gained valuable insight into how our students perceive sources and the research process. We applied what we learned to create new instructional materials and developed a valuable relationship with FYC faculty.     

灾害中生活类物资的供应分析——以汶川地震重灾区物资供应为例

救灾生活类物资在供应中面临着优化运输路线、降低运输成本、缩短运输时间3个难题。文章采用相关机会多目标规划模型,以汶川地震为例,总结并完善了自然灾害救助中的多物资的协作供应模式,为突发性重大灾害中多物资的协作供应的组织、实施、管理提供参考支持。     

Delay composition in preemptive and non-preemptive real-time pipelines

Uniprocessor schedulability theory made great strides, in part, due to the simplicity of composing the delay of a job from the execution times of higher-priority jobs that preempt it. In this paper, we bound the end-to-end delay of a job in a multistage pipeline as a function of job execution times on different stages under preemptive as well as non-preemptive scheduling. We show that the end-to-end delay is bounded by that of a single virtual “bottleneck” stage plus a small additive component. This contribution effectively transforms the pipeline into a single stage system. The wealth of schedulability analysis techniques derived for uniprocessors can then be applied to decide the schedulability of the pipeline. The transformation does not require imposing artificial per-stage deadlines, but rather models the pipeline as a whole and uses the end-to-end deadlines directly in the single-stage analysis. It also does not make assumptions on job arrival patterns or periodicity and thus can be applied to periodic and aperiodic tasks alike. We show through simulations that this approach outperforms previous pipeline schedulability tests except for very short pipelines or when deadlines are sufficiently large. The reason lies in the way we account for execution overlap among stages. We discuss how previous approaches account for overlap and point out interesting differences that lead to different performance advantages in different cases. Further, we also show that in certain cases non-preemptive scheduling can result in higher system utilization than preemptive scheduling in pipelined systems. We hope that the pipeline delay composition rule, derived in this paper, may be a step towards a general schedulability analysis foundation for large distributed systems.

Automatic composition of broadcast sports video

This study examines an automatic broadcast soccer video composition system. The research is important as the ability to automatically compose broadcast sports video will not only improve broadcast video generation efficiency, but also provides the possibility to customize sports video broadcasting. We present a novel approach to the two major issues required in the system’s implementation, specifically the camera view selection/switching module and the automatic replay generation module. In our implementation, we use multi-modal framework to perform video content analysis, event and event boundary detection from the raw unedited main/sub-camera captures. This framework explores the possible cues using mid-level representations to bridge the gap between low-level features and high-level semantics. The video content analysis results are utilized for camera view selection/switching in the generated video composition, and the event detection results and mid-level representations are used to generate replays which are automatically inserted into the broadcast soccer video. Our experimental results are promising and found to be comparable to those generated by broadcast professionals.     

基于全文检索的Segmenter分词算法改进

流行的Segmenter分词算法是开放的java源代码,它是一个很好的分词工具。但是,在全文检索系统中对分词有特殊的要求,例如歧义包客、专业词典等。所以在这里将Segmenter词典和算法都进行了改选,建立了树状词典,在匹配算法中使用了歧义包容法则、分支处理、动态规划和词库预载入。以适应电子商务案例全文检索系统。     

中职信息技术课程学生学习能力培养的实践研究

在职业教育教学实践过程中,教师面临着"如何培养学生的信息技术学习能力?"问题。通过调查分析,发现研究适合职教学生的课堂教学的方式方法,激发学生的学习积极性是非常必要的。只有这样才能培养学生的创造力、自主学习能力,互相协作及自我约束自我管理的能力。     

基于渐进约束违背删除策略的服务合成执行路径优化

在面向服务计算领域,服务合成正成为分布异构资源整合、业务集成的一个新型计算模式。在开放互联的因特网环境下,由于存在多个功能相似但服务质量不同的服务提供商,从而导致一个抽象的服务合成方案存在多条可执行路径。然而,在满足用户综合QoS约束需求的情况下,如何有效协同单个服务的QoS从多条候选路径选出一条优化的执行路径,便成为服务合成QoS研究中的一个关键问题。遗憾的是,该问题还没有得到很好的解决。为此,我们提出一个采取渐进约束违背删除策略建立优化执行路径的方法。我们的方法能够避免探测多条执行路径,而是在靠本地最优化策略建立的执行路径上,通过全局QoS计算和QoS约束检查模型找出QoS约束违背,并进而采取渐进约束违背删除策略逐渐删除这些约束违规,并建立起一条近优的执行路径。实验表明,我们的方法很好地降低了建立优化执行路径的时间复杂性。     

源程序的非编译成份的度量

非编译成份包括注释、程序书写风格和命名规则等几个部分,其中程序书写风格可分为空白行、行缩进和换行等。合理地使用非编译成份,可以提高程序的可读性、可理解性、可修改性、可维护性等质量特性。然而,只有高质量的非编译成份才能起到期望的效果。本文旨在提出一种非编译成份的评价方法,促进这些成份质量的提高。在介绍每一种非编译成份后,分别提出了针对这些成份的度量方法。最后,采用加权合成的方式,得到非编译成份的整体度量。