Privacy in instant messaging: an impression management model

Instant messaging (IM) has evolved into an important tool for collaborative work. It supports informal near-synchronous communication and fosters awareness of the online presence of one's communication partners. Like all awareness systems, IM runs into concerns regarding privacy. Drawing upon prior literature and exploratory interviews, we postulate a model that posits impression management as an underlying cause for privacy desires of IM users. We verify our hypotheses using linear structural modelling on data from a large online survey of IM users across the US. The model establishes that the desire for privacy in IM arises due to the desire for impression management (both directly, as well as indirectly through the desire for visibility of one's impression to oneself). Based on this model, we suggest that IM systems could support privacy needs of users better by providing them with more knowledge and control over aspects that affect their IM-conveyed impression on others (i.e. by making impression management functionality available). Specifically, to help convey and sustain appropriate impressions on IM contacts, IM systems should allow for increased visibility of one's actions to oneself, facilitate easy comparison of one's practices with those of others, and allow one to view oneself from the perspective of others and to make finer-grained adjustments to IM settings than is possible today.     

液压试验机控制部分的改进

国内许多老式液压材料试验机大都改为计算机控制，但直接用于控制的单片机多数AT89C51／52，并足需要A／D、D／A芯片及存储芯片。存在速度慢、精度低、布置麻烦等缺点。本文探讨把SOC芯片引入其中，目前这样的应用在国内还很少见。     

Using the MC68901 multifunction peripheral

First-generation microprocessor peripheral chips were each dedicated to specific functions (e.g. serial interface, parallel interface, timer). Some of today's peripherals are designed to carry out a wide range of functions. The 68901 multifunction peripheral (MFP), for example, combines the functions of a serial interface, a parallel interface, a timer and an interrupt generator. It is not possible to go into detail about the MFP here — its data manual is the size of a small book. Instead, this note illustrates the design of a complete single-board microcomputer built around the 68901 and the 68008 microprocessor.     

Android平台手机防盗系统的安全解决方案

在Android移动应用开发中,手机防盗是一项重要的安全技术。基于Android手机平台,提出并设计了一种手机防盗的安全解决方案,利用一种手机云平台的相关技术,实现了防盗追踪、远程控制和即时通信三个功能模块。首先介绍了整个系统的框架结构,然后详细分析了各个模块的具体实现,最后在手机上进行了测试。实现了通过Web网页的形式对被盗手机进行远程控制,为用户找回手机提供重要的线索。     

基于细观仿真建模的CFRP细观破坏

碳纤维增强树脂基复合材料(CFRP)在细观上呈现纤维、树脂及界面组成的混合态,其切削加工过程的实质为刀具作用下材料细观层面的破坏至切屑宏观形成的演化过程。为了揭示CFRP切削加工过程中材料的细观破坏,建立了CFRP切削的细观有限元模型。该模型在几何上包含了纤维、基体及界面等组成相,而不是使用传统的等效均质建模方法。各组成相不仅考虑了各自不同的材料本构,而且为了能够模拟材料破坏,还将各组成相材料的失效及演化准则考虑其中。该模型可从细观层面更真实地模拟不同纤维角度CFRP单向板切削过程中纤维/基体断裂、界面开裂及演化的过程。仿真结果表明:不同纤维角度下CFRP细观破坏不同,切削0℃FRP时以界面开裂和纤维弯断为主;切削45°/90℃FRP时主要是刀具侵入工件,纤维基体被压断;切削135℃FRP时则以纤维弯曲断裂为主,断裂面往往在加工面以下。通过实验显微在线观测手段验证了模拟结果的正确性。      

基于XMPP的即时通信网关应用研究

XMPP最终要实现不同即时通信系统间的互通。主要介绍对XMPP与其他IM互连互通的网关原理及其应用进行的研究讨论,并以jabber系统与MSN Messenger进行互发信息作为实例进行详细阐述。     

针对密码芯片的电磁模板分析攻击

给出一种简单的电磁信号的获取办法,说明密码芯片的电磁信号能够用一个手工绕制的金属线圈获取,并且其信号幅度和操作数的汉明重量相关.在描述模板攻击原理和步骤的基础上,介绍了针对密码芯片的电磁模板分析攻击,并且针对一个单片机(AT89C52)上实现的DES密码系统进行了电磁模板分析攻击实验,实验成功恢复了DES第16轮使用的48位子密钥.     

RFID transponder integration in metal surgical instruments produced by additive manufacturing

Abstract

Radio frequency identification (RFID) applications are becoming more and more important in logistics, especially for the purpose of tracking and managing items. Real time tracking of medical instruments during a surgical operation belongs to the state-of-the-art applications of this technology. The metallic environment in the operating room represents a big challenge, hampering the readability of the RFID tag. Currently, transponders are joined to metal instruments by bonding or clamping them inside a polymer shell, containing as little metal as possible. Assembling the tags is a time consuming process, which changes the usual shape of the instrument. It also represents a point of failure because of the possibility of losing the tag during the instrument’s life cycle. Selective laser melting (SLM) offers a way to integrate the entire RFID tag in a metallic instrument while keeping the original shape. Instrument manufacturing by SLM allows small wall thicknesses and a reduced temperature impact on the RFID tag during the building process. The production of trial components from IN718 nickel alloy is reported.     

退火热处理对等径角挤压回收Ti-6Al-4V合金微观结构和显微硬度的影响

采用等径角挤压法回收Ti-6Al-4V合金切屑,并研究了回收样品和退火处理样品的微观结构和显微硬度。结果表明:在回收样品中,切屑之间的边界依然存在,而由于剧烈塑性变形,超细晶结构和较强的纤维织构得以形成。退火处理后,切屑边界部分消失,超细晶组织部分再结晶;而与此同时,退火处理样品展现出更宽泛的织构,再结晶晶粒并不存在择优取向。值得注意的是,退火处理样品的显微硬度较回收样品略有升高。     

基于声门闭合瞬间检测的时延算法研究

阐述了基于声门闭合瞬间检测的时延估计方法基本原理,研究了基于希尔伯特变换的线性预测残留误差时延估计法提取时延的方法,并与最大似然广义互相关方法进行了性能分析和比较,结果表明线性预测残留误差的均方偏差最小,抗混响能力强,运算量适中,便于实时实现。