PHP万年历的设计与实现

PHP是目前流行的Web应用程序开发技术,而万年历又是Web应用程序常用的功能组件之一。首先对PHP做出简要介绍,然后对制作万年历相关的PHP时间日期处理加以说明,最后详细论述了PHP日历的制作原理、步骤、要点及设计的具体方法,进而最终实现万年历功能。     

基于日历的时序关联规则挖掘算法

以日历格作为框架来研究时序关联规则,提出了一个有效的挖掘算法。在用户指定的日历模式下,首先通过一次扫描产生所有的频繁2项集及相应的1*日历模式,在此基础上产生k*日历模式,并利用聚集性质产生候选K项集及相应的日历模式,最后扫描事务数据库产生所有的频繁项集及其日历模式。实验证明,该算法具有较好的性能。     

模糊时序关联规则挖掘

借助模糊概念和模糊运算，对时间区间的描述很容易实现。对于指定的日历模式，不同的时间区间可根据它们的隶属度具有不同的权重。在模糊日历代数基础上，结合增量挖掘和累进计数的思想，提出了一种基于模糊日历的模糊时序关联规则挖掘方法。理论分析和实验结果均表明，该算法是高效可行的。     

基于模糊日历约束的时序关联规则挖掘

基于日历约束的时序关联规则挖掘由于其实用性,越来越受到研究者的关注。由于现实中用户很难对时间模式进行精确描述,因此基于模糊日历的时序关联规则挖掘更有现实意义。借助模糊概念和模糊运算,对时间区间的描述很容易实现。对于用户指定的日历模式,不同的时间区间可根据它们的隶属度具有不同的权重。在模糊日历代数的基础上,结合增量挖掘和累进计数的思想,本文提出了一种基于模糊日历约束的关联规则挖掘方法,理论分析和实验结果均表明,该算法是高效可行的。     

基于工作日历的工作流时间管理的研究与实现

随着企业提出“精细化管理”的需求,企业对工作流平台的时效性、作业管理和时间监控提出了更高的要求.为了提高工作流系统对时间维度的处理能力,借鉴ERP系统的工厂日历思想,提出了基于工作日历的工作流时间模型,基于XML规范定义了5种时间表示方法,实现了基于工作日历的工作流时间管理模块.最后实例结果证明该时间模型易于理解和便于软件实现.     

An Algebraic Representation of Calendars

This paper uses an algebraic approach to define temporal granularities and calendars. All the granularities in a calendar are expressed as algebraic expressions based on a single bottom granularity. The operations used in the algebra directly reflect the ways with which people construct new granularities from existing ones, and hence yield more natural and compact granularities definitions. Calendar is formalized on the basis of the algebraic operations, and properties of calendars are studied. As a step towards practical applications, the paper also presents algorithms for granule conversions between granularities in a calendar.     

效用优化的本地差分隐私集合数据频率估计机制

本地差分隐私具有不需要可信第三方、交互少、运行效率高等优点,近年来受到了广泛关注.然而,现有本地差分隐私集合数据频率估计机制未能考虑数据的隐私敏感度差异,将所有数据同等对待,这会对非敏感数据保护过强,导致估计结果准确度低.针对这一问题,定义了集合数据效用优化本地差分隐私(set-valued data utility-optimized local differential privacy, SULDP)模型,考虑了原始数据域同时包含敏感值和非敏感值的情况,在不减弱对敏感值保护的前提下,允许降低对非敏感值的保护.进一步,提出了符合SULDP模型的5种频率估计机制suGRR,suGRR-Sample,suRAP,suRAP-Sample和suWheel,理论分析证实,相对于现有的本地差分隐私机制,所提方案能够对敏感数据实现完全相同的保护效果,并通过降低非敏感数据的保护效果,实现了频率估计结果的准确度提升.最后,在真实和模拟数据集上评估了新的方案,实验结果证明了所提的5种机制能够有效降低估计误差,提升数据效用,其中suWheel机制表现最优.     

产品设计历史的捕获与管理

设计历史管理是记录、回溯和分析产品设计活动的一个重要手段,设计历史管理应该能够自动捕捉产品设计过程的重要信息,该文将产品设计历史分成过程历史和设计意图,过程历史是产品设计活动的具体实施情况,从而为产品设计监控者和设计人员提供一个了解产品设计整个流程的途径;设计意图涉及的是产品设计活动背后的原理,此外,该文开发了产品设计历史捕获与管理的环境。     

基于交互历史在线跟踪机制的可视分析系统

当前可视分析系统对分析推理的迭代过程支持不足,从而给用户带来较大的操作负担和记忆负担.针对这个问题,研究和设计了基于交互历史在线跟踪机制的可视分析系统.首先分析了可视分析过程中的交互任务模型,然后研究了可视分析系统中的交互历史在线跟踪机制,研究了基于交互历史的动作预测方法,接着提出了可视组件自适应布局机制,最后给出了系统的应用实例和评估.系统实例和评估表明,该系统能对用户的分析推理过程提供自然、高效的支持.     

Visualization for Knowledge Graph Based on Education Data

Knowledge graph, also known as scienti c knowledge graph, can reveal the dynamic development rules in complex knowledge elds. How to clearly present the internal structure of knowledge graph is particularly important, however, the current visualization research based on knowledge graph is rare. In this paper, varieties of data related to education are mined from massive web data, and are fused together. Then knowledge graph which is centered on educational events is constructed utilizing extracted named entities and entity relations. We construct a visual analysis platform for education knowledge graph, EduVis, which can support users to do associated analysis of education, and enable users to obtain the public opinions. In EduVis, we design and implement a) a word cloud treemap to provide an overview of education knowledge graph, b) a layout of events relation network graph based on topological structure and timeline to explore in details, c) a click tracking path to record the history of users'' clicks and help users to backtrack. The case studies show that the aforementioned visual analysis methods for our knowledge graph can meet users'' demands for data analysis tasks.     

股指期货套利管理系统

针对我国股指期货市场存在的问题——理论与实际应用脱节,造成股指期货市场的发展需求和实际发展条件不平衡,提出构建股指期货套利管理系统的策略. 依据实地调研资料进行系统设计,使用C#实现股指期货套利管理系统（SIFAM-System）. 系统实现了基于基差的跨期套利和基于无套利区间的跨期套利,以及与套利相关的信息管理功能. SIFAM-System利用计算机实现模型计算、行情监控、套利机会的判断及开平仓,达到了辅助投资者决策的目的,也为股指期货市场的发展问题提供了从理论到实现的解决策略.     

基于细粒度数据的智能手机续航时间预测模型

如今,智能手机已成为人们日常生活中重要的组成部分.然而,在智能手机软硬件能力高速发展的同时,智能手机的电池能力却未能取得突破性的进展.这导致电池的续航能力经常会成为用户使用智能手机时的体验瓶颈.为了提高用户使用体验的优良感受,一种可行的方法是为用户提供电池续航时间预测.准确的电池续航时间预测能够帮助用户更加高效地规划其...     

Investigating respondent multitasking in web surveys using paradata

Computers play an important role in everyday multitasking. Within this context, we focus on respondent multitasking (RM) in web surveys. RM occurs when users engage in other activities while responding to a web survey questionnaire. The conceptual framework is built on existing literature on multitasking, integrating knowledge from both cognitive psychology and survey methodology. Our main contribution is a new approach for measuring RM in web surveys, which involves an innovative use of the different types of paradata defined as non-reactive electronic tracks concerning respondents' process of answering the web questionnaire. In addition to using questionnaire page completion time as a measure of RM, we introduce ‘focus-out’ events that indicate when respondents have left the window containing the web questionnaire (e.g., to chat, email, browse) and then returned. The approach was tested in an empirical study using a web survey on a student sample (n = 267). The results indicate that 60% of respondents have multitasked at least once. In addition, they reveal that item nonresponse as an indicator of response quality is associated with RM, while non-differentiation is not. Although this study confirms that a paradata-based approach is a feasible means of measuring RM, future research on this topic is warranted.     

一种基于DSP在线更新配置程序的实现方法

针对系统设计通用化的需求,设计了一种使用FLASH存储器作为数据存储器件,配合微处理器程序,利用复杂可编程逻辑器件（CPLD）更新和配置可编程器件,实现对现场可编程门阵列（FPGA）程序和数字信号处理器（DSP）程序在线更新的方法。本文给出了系统构成和实现途径,并对ALTERA可编程逻辑器件和TMS320C6000系列DSP的加载和系统设计实现进行了较详细的说明。     

Short Web-based versions of the perceived stress (PSS) and Center for Epidemiological Studies-Depression (CESD) Scales: a comparison to pencil and paper responses among Internet users

This study reports results from a format comparison between Web-based and pencil and paper questionnaires measuring two well-validated measures of psychological distress among 530 frequent Internet users studying at an on-line University (Open University of Catalonia, UOC). A four-item version of the Perceived Stress Scale (PSS) and a seven-item version of the Center for Epidemiological Studies-Depression Scale (CESD) were randomly administered in Web-based and pencil and paper format. Internal consistency analyses showed that these two brief versions were reliable for on-line assessment. Also, no differences in Cronbach αs were found between formats. Exploratory as well as multigroup factor analysis techniques showed that factor structures were invariant across formats. Overall, results revealed that respondents did not bias their responses in the Web-based condition. As these findings suggest, when familiarity with technology is high among respondents and sample procedures are followed to maximize control for potential participants, Web-based and paper and pencil formats are virtually equivalent, as in the two brief measures of psychological distress used in this study.     

利率、汉字、日历时钟电子显示屏的设计

根据银行系统的需要 ,设计并制作了能显示利率、日历时间和汉字的电子显示屏。分析了系统的工作原理 ,论述了其软件设计方法 ,该系统线路简单、造价低、实用性强。     

PVaniM: a tool for visualization in network computing environments

Network computing has evolved into a popular and effective mode of high performance computing. Network computing environments have fundamental differences from hardware multiprocessors, involving a different approach to measuring and characterizing performance, monitoring an application's progress and understanding program behavior. In this paper, we present the design and implementation of PVaniM, an experimental visualization environment we have developed for the PVM network computing system. PVaniM supports a two-phase approach whereby on-line visualization focuses on large-grained events that are influenced by and relate to the dynamic network computing environment, and postmortem visualization provides for detailed program analysis and tuning. PVaniM's capabilities are illustrated via its use on several applications and a comparison with single-phase visualization environments developed for network computing. Our experiences indicate that, for several classes of applications, the two-phase visualization scheme can provide valuable insight into the behavior, efficiency and operation of distributed and parallel programs in network computing environments. © 1998 John Wiley & Sons, Ltd.     

On-line synchronous scientific argumentation learning: Nurturing students' argumentation ability and conceptual change in science context

The purpose of this study is to examine the difference in effectiveness between two on-line scientific learning programs – one with an argumentation component and one without an argumentation component – on students' scientific argumentation ability and conceptual change. A quasi-experimental design was used in this study. Two classes of 8th grade students (the experimental group) received the on-line scientific argumentation learning program about chemical reaction, and the other two classes of 8th grade students (the control group) received the same on-line scientific learning program about chemical reaction, but without argumentation, for two weeks. All 140 students were administered the scientific conception test, conceptual change test, and argumentation test before, one week after, and eight weeks after learning. In addition, the experimental group students' on-line argumentation process was collected. Results showed that the students of the experimental group significantly outperformed the control group, regardless of scientific conceptions, conceptual change, and argumentation. Regression results indicated that hold of scientific conceptions is the best predicator for students' conceptual change, followed by argumentation ability. The quantity and quality of scientific arguments that students generated in a series of argumentation questions improved across the four topics. In addition, students also successfully changed their conceptions from pre- to post-driving questions across four topics. This clearly demonstrates that students' argumentation ability and conceptual change were both facilitated through receiving the on-line Synchronous Argumentation science learning program.     

Measuring emotional valence to understand the user's experience of software

This paper reports on the results of two studies that used facial electromyography (EMG) measures combined with verbal and performance measures to provide feedback in the software design process on the user's emotional state. The first study assessed 16 participant's emotional responses while they passively viewed mock ups of proposed new operating system features. The second study measured the emotional responses of 15 participants while they actively used one of two versions of a media player. This multimodal assessment method was able to provide a sensitive measure of the desirability of the proposed software features, and a measure of emotional tension and mental effort expended in the interactive tasks.     

Delivering unprecedented access to learning through podcasting as OER,but who's listening? A profile of the external iTunes U user

Little is known about the learners who download iTunes U resources but do not belong to the Higher Education institutions that provide them. This paper presents the first full profile of the external iTunes U learner and their practices and opinions of the materials they download. The data was gathered through a large survey (over 2000 responses) carried out over two years using the iTunes U site from The Open University. It shows that external iTunes U learners are very different from the internal users and practices described in the literature so far: there are more men than women, mostly middle-aged, and they use the resources mostly for personal reasons. Despite the fact that respondents used the iTunes U site from a distance university, the paper argues that the respondents are comparable to external learners who use resources from other iTunes U sites. This profile of the iTunes U user provides a clearer picture of the target listener and can help inform and improve the materials design and delivery strategies for iTunes U as an independent learning tool and Open Educational Resources (OER) in general. The article also proposes areas for further research and argues for more studies into external learners' use of podcasting resources.