简论关系数据库的查询优化

数据库的应用日益广泛,随着数据量的增大,查询效率越来越爱人们关注。为了提高查询的效率．在考虑处理器的速度、1／O速度、存储器的容量、操作系统、采取何种的数据库服务系统等方面的同时,对于特定服务器来说查询的效率主要取决于DBA（数据库管理员）所给定的查询语句的优化。     

一种体检预约查询App的跨平台设计与实现

为了便于客户进行体检预约和体检报告查询,开发了一款体检预约查询手机端App.将数据展示、数据服务和数据存储进行分离,设计了三层架构,服务器采用DataSnap技术实现数据控制逻辑,客户端采用跨平台开发的方式,一次编码,生成Android和IOS两个版本的手机端应用程序.并针对体检报告查询延迟的问题,将数据库进行了数据归...     

高性能短消息发送平台的设计与实现

为了解决当前短信网关发送平台资源利用率低,数据维护成本高的问题,研发设计了一种新型短消息发送平台,采用集群计算提供服务,能承载大量客户的并发操作,同时达到实时数据发送、数据存储与数据查询的要求。系统实际上线运行结果表明可以满足高性能的短信网关数据处理业务。     

基于ASP.NETMVC框架的高校在线财务查询系统设计与实现

为了更好地进行高校财务信息管理,设计和实现了基于APS.NETMVC开发模式的高校在线财务查询系统。系统前端程序语言采用C#,后端数据库采用Oraclellg,以软件工程思想为指导,实现了教职工财务信息查询、学生财务信息查询、部门财务信息查询和财务通知等功能,提高了财务管理水平,为领导决策提供了数据支撑。     

基于时空索引的校园地理信息系统构建

时空索引技术是近年来地理信息系统领域的研究热点,如何有机结合空间和时间信息,提高查询效率是重中之重。本文构建了飘浮模型的时空索引机制,以三层数据查询结构保证时空的有效结合。同时,创新的采用影像与矢量数据配准的方式共同作为数据源,降低系统成本,增加直观效果。实践表明该索引机制可以有效提高查询效率,基于该模型的校园地理信息平台运行效果良好。     

一种在移动GIS环境下基于R树的并行窗口查询系统模型

窗口查询（Window Query）是移动地理信息系统（Mobile Geographic Information System）各类具体应用中的核心功能。为了提高移动GIS系统的查询效率（I／O开销、响应时间、丢失率），本文对实时环境下窗口查询分解、调度和并行处理等问题做了阐述，讨论了基于内存R树（Memory R—tree）实现并行窗口查询的方法。     

分布式环境下遥感影像数据存储方法

为了对遥感影像数据进行高效地存储与管理,解决传统的存储与查询效率不高的问题。设计一种基于猫群算法的遥感影像并行存储算法,采用线性四叉树对地理空间进行划分和编码,利用MapReduce并行计算框架和猫群优化算法来构建金字塔,把地物标识码、四叉树索引ID两种信息作为行键,采用HBase分布式数据库对影像数据进行存储。实验表明,该方法在金字塔构建的过程中有效的提高了遥感影像的存储效率且保证了数据的完整性。在查询方面,改进的行键不仅达到了筛选数据的目的而且提高了读取效率。研究成果可满足对海量影像高效存储、管理的需求,具有很好的可行性和可扩展性。     

基于RFID标签隐私查询策略

为了能有效保证射频识别(RFID)系统中用户的隐私和数据安全,运用分布式RFID询问应答认证协议,Elgamal密码系统、认证机制和可验证门限秘密共享等协议对标签数据认证查询.该策略不仅查询可靠,还具有保护被查询对象和查询结果隐私安全等特点.通过其安全性能分析和效率分析,说明了本协议具有高效的性能和良好的安全性、可靠性.     

基于TPC—H的数据生成优化方法

通过对海量数据生成方法的初步研究,把数据库的测试与查询建立在TPC—H标准上。根据TPC—H标准建立了TPC—H的测试模型,通过此模型可以反映出系统在处理查询时各个方面的能力。采用树形结构提出了数据生成优化方法,能更好地提高生成数据效率。     

外贸业务客户关系管理电子商务系统设计与研究

介绍在外贸业务信息系统基础上设计研究的客户型客户关系管理(CRM)系统.外贸过程中.为了适应客户业务信息需求,应在客户管理关系(CMR)基础上设计研究客户型CRM系统.CRM应用系统主要有客户适时查询经营产品、商品询价的快速响应、外销合同订立过程简捷、外销合同执行过程及时通告相关信息、付款支付查询、赔款支付查询和业务过程警示等方面功能.在外贸市场竞争中,保证信息安全是信息系统非常重要的方面.     

基于微信小程序的学生成绩信息查询系统研究与设计

微信小程序以其体量轻小,无需安装、卸载,触手可及、用完即走的技术创新,越来越多地被应用于不同场景中。借助微信小程序,结合PHP语言、MySQL数据库、Json数据等技术设计与开发一套学生成绩信息查询系统,能够实现高校学生成绩信息的便捷、实时查询。     

Which Type of Inquiry Project Do High School Biology Students Prefer: Open or Guided?

In teaching inquiry to high school students, educators differ on which method of teaching inquiry is more effective: Guided or open inquiry? This paper examines the influence of these two different inquiry learning approaches on the attitudes of Israeli high school biology students toward their inquiry project. The results showed significant differences between the two groups: Open inquiry students were more satisfied and felt they gained benefits from implementing the project to a greater extent than guided inquiry students. On the other hand, regarding documentation throughout the project, guided inquiry students believed that they conducted more documentation, as compared to their open inquiry peers. No significant differences were found regarding ??the investment of time??, but significant differences were found in the time invested and difficulties which arose concerning the different stages of the inquiry process: Open inquiry students believed they spent more time in the first stages of the project, while guided inquiry students believed they spent more time in writing the final paper. In addition, other differences were found: Open inquiry students felt more involved in their project, and felt a greater sense of cooperation with others, in comparison to guided inquiry students. These findings may help teachers who hesitate to teach open inquiry to implement this method of inquiry; or at least provide their students with the opportunity to be more involved in inquiry projects, and ultimately provide their students with more autonomy, high-order thinking, and a deeper understanding in performing science.     

Understanding teacher design practices for digital inquiry–based science learning: the case of Go-Lab

Designing and implementing online or digital learning material is a demanding task for teachers. This is even more the case when this material is used for more engaged forms of learning, such as inquiry learning. In this article, we give an informed account of Go-Lab, an ecosystem that supports teachers in creating Inquiry Learning Spaces (ILSs). These ILSs are built around STEM–related online laboratories. Within the Go-Lab ecosystem, teachers can combine these online laboratories with multimedia material and learning apps, which are small applications that support learners in their inquiry learning process. The Go-Lab ecosystem offers teachers ready–made structures, such as a standard inquiry cycle, alternative scenarios or complete ILSs that can be used as they are, but it also allows teachers to configure these structures to create personalized ILSs. For this article, we analyzed data on the design process and structure of 2414 ILSs that were (co)created by teachers and that our usage data suggest have been used in classrooms. Our data show that teachers prefer to start their design from empty templates instead of more domain–related elements, that the makeup of the design team (a single teacher, a group of collaborating teachers, or a mix of teachers and project members) influences key design process characteristics such as time spent designing the ILS and number of actions involved, that the characteristics of the resulting ILSs also depend on the type of design team and that ILSs that are openly shared (i.e., published in a public repository) have different characteristics than those that are kept private.

     

Patterns of scaffolding in computer‐mediated collaborative inquiry

There is wide agreement on the importance of scaffolding for student learning. Yet, models of individual and face‐to‐face scaffolding are not necessarily applicable to educational settings in which a group of learners is pursuing a process of inquiry mediated by technology. The scaffolding needed for such a process may be examined from three perspectives: the organization of activities, the affordances of tools, and process‐level guidance. The purpose of the present study was to assess three tutors’ contributions to university students’ computer‐mediated discourse organized as a question‐driven inquiry process. In all, 17 students participated in the discourse as part of their studies in a cognitive psychology course. Quantitative and qualitative analyses were conducted to investigate critical patterns and possible effects of the tutors’ process‐level scaffolding. During the process, the more experienced tutors acted as meta‐level commentators, whereas the less experienced tutor participated in the inquiry as a co‐inquirer who also produced inquiry questions. More elaborate scaffolding to foster students’ metacognitive awareness of the inquiry strategies was generally lacking in all three tutors’ data. Implications for pedagogical improvement in collaborative, computer‐supported educational settings are discussed.     

Reconceptualising inquiry in science education

Decades of discussion and debate about how science is most effectively taught and learned have resulted in a number of similar but competing inquiry models. These aim to develop students learning of science through approaches which reflect the authenticity of science as practiced by professional scientists while being practical and manageable within the school context. This paper offers a collection of our current reflections and suggestions concerning inquiry and its place in science education. We suggest that many of the current models of inquiry are too limited in their vision concerning themselves, almost exclusively, with producing a scaffold which reduces the complex process of inquiry into an algorithmic approach based around a sequence of relatively simple steps. We argue that this restricts students’ experience of authentic inquiry to make classroom management and assessment procedures easier. We then speculate that a more integrated approach is required through an alternative inquiry model that depends on three dimensions (conceptual, procedural and personal) and we propose that it will be more likely to promote effective learning and a willingness to engage in inquiry across all facets of a students’ school career and beyond.     

探究式教学在高职化学教学中的运用初探

在高职化学教学中,教学方法多种多样,探究式教学是其中一种。其应用包括创设情境,设疑诱思,确定探究方案,检验假设,讨论结果,激励评价等环节。成功地运用探究式教学,能够提高学生的科学素养,促进学生实践能力的发展,能培养出更多、更好的实用型人才。     

Co-Organizing the Collective Journey of Inquiry With Idea Thread Mapper

This research integrates theory building, technology design, and design-based research to address a central challenge pertaining to collective inquiry and knowledge building: How can student-driven, ever-deepening inquiry processes become socially organized and pedagogically supported in a community? Different from supporting inquiry using predesigned structures, we propose reflective structuration as a social and temporal mechanism by which members of a community coconstruct/reconstruct shared inquiry structures to shape and guide their ongoing knowledge building processes. Idea Thread Mapper (ITM) was designed to help students and their teacher monitor emergent directions and co-organize the unfolding inquiry processes over time. A study was conducted in two upper primary school classrooms that investigated electricity with the support of ITM. Qualitative analyses of classroom videos and observational data documented the formation and elaboration of shared inquiry structures. Content analysis of the online discourse and student reflective summaries showed that in the classroom with reflective structuration, students made more active and connected contributions to their online discourse, leading to deeper and more coherent scientific understandings.     

Evaluation of simulated decision making: A response to Ysseldyke,Algozzine, Regan,and Potter

A recent study challenged the ability of evaluation teams to select technically adequate data sources. Aspects of methodology and focus of inquiry restrict the interpretation of results. A more productive line of inquiry is suggested.     

Teacher epistemology and scientific inquiry in computerized classroom environments

A 20-week classroom-based study was conducted to investigate the extent to which a computerized learning environment could facilitate students' development of higher-level thinking skills associated with scientific inquiry. In two classes students' interactions with a scientific data base—Birds of Antarctica—were closely monitored, and the mediating roles of the teachers' epistemologies were examined. Interpretive data were generated and analyzed in relation to a constructivist perspective on learning. In the class where the teacher implemented a constructivist-oriented pedagogy, students took advantage of enhanced opportunities to generate creative questions and conduct complex scientific investigations. These higher-level thinking skills were much less evident in the class in which a more transmissionist-oriented pedagogy prevailed. The results of the study suggest that it is not the computer itself that facilitates inquiry learning; the teacher's epistemology is a key mediating influence on students' use of the computer as a tool of scientific inquiry.