Ddelta: A deduplication-inspired fast delta compression approach

Delta compression is an efficient data reduction approach to removing redundancy among similar data chunks and files in storage systems. One of the main challenges facing delta compression is its low encoding speed, a worsening problem in face of the steadily increasing storage and network bandwidth and speed. In this paper, we present Ddelta, a deduplication-inspired fast delta compression scheme that effectively leverages the simplicity and efficiency of data deduplication techniques to improve delta encoding/decoding performance. The basic idea behind Ddelta is to (1) accelerate the delta encoding and decoding processes by a novel approach of combining Gear-based chunking and Spooky-based fingerprinting for fast identification of duplicate strings for delta calculation, and (2) exploit content locality of redundant data to detect more duplicates by greedily scanning the areas immediately adjacent to already detected duplicate chunks/strings. Our experimental evaluation of a Ddelta prototype based on real-world datasets shows that Ddelta achieves an encoding speedup of 2.5×–8× and a decoding speedup of 2×–20× over the classic delta-compression approaches Xdelta and Zdelta while achieving a comparable level of compression ratio.     

基于ANSYS的车架横梁结构改进设计

由于某车型整体式铸造横梁在使用过程中经常出现断裂现象，特对其结构进行改进设计。采用有限元分析的方法对改进前后两种结构的等效应力进行分析比较，并通过分析结果来验证改进设计的合理性。     

西部地区建筑设计实践的不同途径

西部地区的建筑行业因近年来市场的竞争而面临新的处境,即在经济发展相对落后、资金投入有限的条件下如何维持自身的设计水平;在相对不均等的境遇中,如何发掘自身潜力创造新的机遇.以地方建筑文化为依托进行设计,发掘工业化时代成果与建筑设计结合,利用地域优势创作,这些都是当代西部建筑设计得以发展的途径.建筑师们通过不同方式的创作实践,取得了良好的成果,并以他们的实例说明了这些途径的可行性.     

Promoting and scaffolding argumentation through reflective asynchronous discussions

The purpose of this quasi-experimental study was to explore the impact of asynchronous discussion on the quality and complexity of college students’ arguments. Three different cohorts of students registered in a physical science course in 2009 Fall, 2010 Spring, and 2010 Fall semesters were briefly supported with scaffolding in class and then involved in argumentation about socio-scientific issues as take-home assignments. Each cohort was divided into an asynchronous online communication group and a paper–pencil group. The findings showed that very few students’ arguments from either group were rated low in quality levels of 1 or 2 on a five-scale level. Additional comparisons revealed that the asynchronous online communication group students slightly outperformed their counterparts in terms of mean quality level of arguments (effect sizes ranged from 0.25 to 0.35) and the frequency of rebuttals. The major finding is that after only one hour of scaffolding followed by the opportunity to practice argumentation at home, students’ argumentation skills were slightly better developed through reflective asynchronous online discussions about socio-scientific issues than through paper-pencil practice.     

Courseware development model (CDM): The effects of CDM on primary school pre-service teachers' achievements and attitudes

The main purpose of this study is to design a “Courseware Development Model” (CDM) and investigate its effects on pre-service teachers' academic achievements in the field of geography and attitudes toward computer-based education (ATCBE). The CDM consisted of three components: content (C), learning theory, namely, meaningful learning (ML), and multimedia (M). The CDM is designed to show the synthesis of the C and M components under ML. In this study, an experimental design including pre-test and post-test groups is used to define the efficiency of the CDM. There are 31 pre-service teachers in the control group, 28 pre-service teachers in the meaningful learning theory group-ML, and 30 pre-service teachers in GTC group that uses geography teaching courseware-GTC based on the CDM. The results of the analysis indicate that the courseware is quite effective, improving pre-service teachers' academic achievements as well as their ATCBE scores. The results also suggest that the new model has an appropriate structure for courseware design.     

An analysis of educational informatization level of students,teachers, and parents: In Korea

Korea is recognized as one of the most advanced countries in terms of informatization. The development of informatization has impacted education, and education informatization has contributed to the improvement of teaching in the classroom. Accordingly, education informatiozation is one of the paramount pedagogical issues in South Korea. This study evaluated the effect of Korea’s education informatization policy qualitatively. The access to education information, competency, utilization and the satisfaction levels of students, teachers and parents, who are the groups most directly affected by education policies, were analyzed. In addition, the level of education informatization, the growth of which had been expected by experts, was measured. The rate of achievement as compared to the level expected by experts was analyzed. According to the results of the analysis, the rate of achievement of all three groups was low, and the education informatization level of parents was the lowest. On the basis of the results of this study, we have suggestions about the kind of effort that is needed to raise the level of education informatization.     

Framework for the evolution of acquiring knowledge modules to integrate the acquisition of high-level cognitive skills and professional competencies: Principles and case studies

The changing profile of students, the expectations of business and the capabilities offered by Information and Communication Technologies (ICT) makes it necessary to change teaching practices, particularly in higher education. This paper proposes a methodological framework destined to force disciplinary course modules to evolve in order to integrate high-level cognitive skills and professional competencies. In this paper, we examine this framework in terms of the primary currents in educational psychology: behaviorism, cognitivism, constructivism and social constructivism. We present and analyze three case studies showing the evolution of three disciplinary course modules. We show that the lessons taught in these three modules are more motivating and more efficient, producing results that are closer to what employers are asking of their employees.     

The implementation and evaluation of a mobile self- and peer-assessment system

Recently, more and more researchers have been exploring uses of mobile technology that support new instructional strategies. Based on research findings related to peer and self assessment, this study developed a Mobile Assessment Participation System (MAPS) using Personal Digital Assistants (PDAs) as the platform. In addition, the study proposes an implementation model of the MAPS that should facilitate the effectiveness of self- and peer-assessment in classrooms. The researcher argues that teachers and students can benefit from MAPS in various regards including more flexible assessment arrangement, more efficient use of time, and more opportunities for student reflection on learning and assessment. Thirty-seven students taking teacher-education courses with the researcher participated in this study, and these students employed the MAPS to conduct two-round assessment activities that would help these students assess both their own and one another’s final projects. Both the students’ valid responses in a survey herein and scores obtained from the assessment activities confirmed the benefits of the MAPS and its implementation model. Yet, the students voiced such concerns as the objectivity of peer-assessment and the difficulty of providing constructive feedback, and the correlation analysis indicated a lack of consistency between teacher-grading and student-grading.     

田口试验设计的改进及其应用研究

表面贴装技术的生产制程涉及机器、材料和工作环境等多重变因，其繁琐复杂更胜于传统制造流程，因此如何管控生产变因以提高产品品质成为业界的重大课题。通过对田口试验设计方法中存在调整因子的望目型品质特性考量，引入检验因子，对正交表修改，建立基于因子分类的两阶段优化模型，构建改进型田口试验设计。并结合某SMT企业的钢板印刷制程，构建了田口试验设计平台，进行制程参数的优化设计，取得了满意的效果。