An asynchronous P300 BCI with SSVEP-based control state detection

In this paper, an asynchronous brain-computer interface (BCI) system combining the P300 and steady-state visually evoked potentials (SSVEPs) paradigms is proposed. The information transfer is accomplished using P300 event-related potential paradigm and the control state (CS) detection is achieved using SSVEP, overlaid on the P300 base system. Offline and online experiments have been performed with ten subjects to validate the proposed system. It is shown to achieve fast and accurate CS detection without significantly compromising the performance. In online experiments, the system is found to be capable of achieving an average data transfer rate of 19.05 bits/min, with CS detection accuracy of about 88%.     

An empirical study of the factors affecting Internet security for the financial industry in Taiwan

Security is a pre-requisite for internet banking. The purpose of this study is to explore the factors that are important to the implementation of Internet security of different types of financial institutes. A questionnaire survey was conducted on all types of financial institutions in Taiwan. A total of 573 questionnaires were mailed out to CIOs in domestic financial institutions with a response rate of 11.69%. The results of the study showed that different types of financial institutions have significantly different levels of concern in terms of factors such as the concern of software systems, hardware security, executives support, internal Internet system users, organizational characteristics, and organizational security policy. The implications of this study are discussed and suggestions for future research are presented.     

单模光纤耦合器耦合系数影响因素的研究

从理论上推导了2×2单模光纤耦合器耦合系数的计算公式。然后结合实际制作条件进行了合理的近似,从而分析了在实际制作中两条拉锥光纤之间的水平间距d0及拉锥基座垂直偏差y对于耦合器耦合系数的影响。     

单管对称侧泵的直角反射镜腔耦合效率分析

一种已获美国专利的LD侧面抽运固体激光器新结构 ,能将一个半导体激光器的输出光分成四份 ,从四个方向对称泵浦激光棒。本文对这种直角反射镜聚光腔泵浦结构耦合效率影响因素进行了理论分析与计算 ,并采用这种聚光腔进行实验 ,得到了初步的结果 ,并对结果进行了分析。     

An exploratory study of intrafirm process innovations transfer in Asia

This paper examines how seven process innovations have been shared and adopted (or not adopted) between four factories of a multinational company located in Asia. In contrast to most previous studies in this area, these process innovation diffusions happened in a bottom-up manner in which the decision to share and to adopt is made by the individuals at the sites involved rather than by top management either at a local or corporate level. We observe that the factors enabling or discouraging the adoption of process innovation are highly dynamic. When work priorities shift over time, motivating factors once perceived as primary may become secondary, leading to nonadoption of the innovations. As the engineers face an increasing load of other tasks which also demand time and effort, the decision to adopt the innovation or not seems to depend more on the effort required to adapt the innovation for local use than other factors. Innovations which are highly embedded in the original settings face slimmer chance of adoption by other sites as they are likely to require more effort in adapting them for local use. In contrast, innovations which are less embedded in original settings are more likely to be adopted due to the low adaptation effort needed.     

An exploratory study for investigating the critical success factors for cloud migration in the Saudi Arabian higher education context

Saudi universities have at their disposal a huge number of low cost IT resources to aid in teaching, research and learning. By migrating to cloud services, Saudi universities will be moving data and programs from local servers to the internet, thereby providing users with the ability to access and share information at any time from multiple devices. The migration to cloud-based IT resources is not yet widespread in Saudi universities due to several challenges including security, legal policies and implementation. At present, there is lack of research and guidance for Saudi universities on how to overcome these challenges and how contextual factors can influence the successful migration to the educational clouds.This research presents a framework for the successful migration to cloud technology in the Saudi Arabian universities. In this research, a set of key critical success factors (CSFs) were identified by synthesizing components from studies concerned with the migration of cloud for higher education and factors identified from the successful implementation of WBL (Web Based Learning) and ERP (Enterprise Resource Planning) on higher education in Saudi Arabia. Based on this knowledge, the proposed framework was evaluated via expert review and a survey by IT specialists from the Saudi universities. The initial CSFs were updated based on the expert reviews and the results were analysed. Based on the findings at this stage, additional CSFs were added to the framework as suggested by the experts. Subsequently, in order to confirm the reviewed CSFs, additional investigation via a structured online questionnaire was conducted and the outcome was analysed via one-sample t-test with the data integrity analysed via Cronbach’s alpha. The outcome indicated the majority of CSFs to be statistically significant except the Physical Location CSF. Potential future study and contributions are discussed.     

The persistence of print among university students: An exploratory study

As use of digital devices has grown, university students (along with faculty and administrators) are considering whether academic reading should be done in print or on digital screens. Some studies have indicated that comprehension in the two media is equivalent, while other research has questioned this conclusion. Furthermore, we have little systematic knowledge about students’ own attitudes and practices regarding reading in hardcopy versus onscreen.The present investigation gathered quantitative and qualitative survey data from 429 university students in the US, Japan, Germany, Slovakia, and India. The quantitative findings revealed high levels of affirmation about advantages of reading in print. Nearly 92% said they concentrated best when reading in print, and more than four-fifths reported that if cost were the same, they would prefer print for both schoolwork and pleasure reading. Students reported they were more likely to re-read printed material than digital; they were also more likely to multitask when reading onscreen. Qualitative questions asked what students liked most and liked least about reading in hardcopy and reading digitally. Using a fine-grained coding scheme, these responses were quantified. Advantages reported for print included ease of annotation and paper’s tactile properties, while among the disadvantages were lack of convenience and expenditure of environmental or monetary resources. The biggest advantage of screen reading was convenience, while the primary disadvantages were eyestrain and distraction.     

基于蚁群算法的P2P网络资源发现算法

Gossip协议是P2P网络的一种流行的资源发现算法,但它没有考虑寻找最低成本的资源。论文提出了基于蚁群算法的新的资源发现算法,在查找资源的同时,综合考虑路径载荷、延时等因素,找到综合费用最低的路径。仿真实验表明,该算法比Dijkstra算法解集的平均综合费用低10%左右,从而能更有效地利用网络资源。     

基于P2P流量检测的签名特征匹配研究

P2P网络应用快速发展,带来网络安全防护漏洞和隐患。如何有效地监控P2P流,进行相关的流识别、流筛选、流控制是流管理中的重要问题。通过分析P2P协议及签名特征,提出一种基于签名特征的P2P流分析方法,通过实验分析相关P2P应用软件,得到相关软件的签名特征,并判断网络数据流是否为P2P流。可有效地提高P2P流识别的效率,解决检测信息过多、过滤信息性能瓶颈等问题。     

Estimating factors affecting project task size in product development-an empirical study

This paper addresses the methodology used to determine the amount of human resources needed to develop products. It is based on an empirical study of five firms in different industries. The methods rely on technical experts operating within budget constraints. The specific methods vary from relatively ad-hoc approaches to database-driven, centralized, and validated approaches. This variation is largely correlated with project and overall product development organization scale in a logical fashion in that larger projects and organizations move away from individual decision-makers toward centralized, objective, and validated methods. The project characteristics used by the experts and implicitly utilized in the database models to assess project complexity are also detailed in this paper. These characteristics are categorized based on a project complexity framework. We found that the scale of a project and the amount of "stretch" are the two most widely used characteristics for estimating project complexity. We found no utilization of the level of either component or task interactions in estimating project complexity by the firms studied. We also found no empirical evidence for interactions being a determinant of project difficulty despite a fair amount of theoretical concern with their importance in project complexity. In addition, we analyzed the accuracy of methods and conclude that since the accuracy at a higher level masks resource allocation problems at a lower level, the accuracy should be followed at multiple levels.     

A mathematical study of some biomechanical factors affecting theoscillometric blood pressure measurement

A mathematical lumped parameter model of the oscillometric technique for indirect blood pressure measurement is presented. The model includes cuff compliance, pressure transmission from the cuff to the brachial artery through the soft tissue of the arm, and the biomechanics of the brachial artery both at positive and negative transmural pressure values. The main aspects of oscillometry are simulated i.e., the increase in cuff pressure pulsatility during cuff deflation manoeuvres, the existence of a point of maximum pulsations (about 1.5 mmHg) at a cuff pressure close to mean arterial pressure, and the characteristic ratios for cuff pressure pulsatility at systole and diastole (0.52 and 0.70, respectively, with this model, using basal parameters and an individual set of data for the arterial pressure waveform). Subsequently, the model is used to examine how alterations in some biomechanical factors may prejudice the accuracy of pressure measurement. Numerical simulations indicate that alterations in wall viscoelastic properties and in arterial pressure pulse amplitude may significantly affect the accuracy of pressure estimates, leading to errors as great as 15-20% in the computation of diastolic and systolic arterial pressure. By contrast, changes in arterial pressure mean value and cuff compliance do not seem to have significant influence on the measurement. Evaluation of mean arterial pressure through a characteristic ratio is not robust and may lead to misleading results. Mean arterial pressure may be better evaluated as the lowest pressure at which cuff pulse amplitude reaches a plateau. The obtained results may help to explain the nature of errors which usually limit the reliability of arterial pressure measurement (for instance in the elderly)     

Beliefs about computer-mediated information services among college students: An exploratory study

Few prototypical media have been as widely researched as the computer during its early stages of development. But, in gaining a better understanding of this adoption dynamic, it is useful to assess why online services have generated so little interest to date. The purpose of this study is to assess psychological dimensions of interest and apprehension concerning the use of computer-mediated communication services. Perspectives on Diffusion Theory, technology needs, and apprehension are applied to examine attitudes toward the impact of computer information services on society. The large degree of variance attributable to computer utility measures implies a new set of attitudinal variables to supplement demographics and technology adoption measures. Implications of study findings are discussed.     

An integrated system for real-time detection of stiff masses with a single compression

An integrated system is proposed for real-time imaging of tissue deformation in response to externally applied mechanical compression. The purpose of the system is to noninvasively detect tissue lesions based on their stiffness. The method includes applying external compression to the examined subject and acquiring magnetic resonance strain-encoded images using a real-time pulse sequence. In the proposed system, only a single compression is necessary to obtain a two-dimensional map of tissue deformation in a slice, eliminating the need for a complicated compressing device. The system was built and validated using phantom experiments.     

Application of the small-zone concept to police communications in population centers: An exploratory study

This paper examines the possible application to police communications of a dispersed array of low-power stations operating under an area-wide channel plan. A technique is given for generating the complex channel plans that are used. It is shown that police effectiveness is not reduced and that the concept permits unlimited growth of cities at the highest population density with a fixed and reasonable number of new channels.     

影响ADSL线路质量的因素

ADSL（非对称数字用户线）是在现有的用户双绞铜线上传送高速非对称数字信号的一种新技术,其中非对称性表现在局端到用户端,下行速率可达1.5～8Mb/s;用户端到局端的上行信道包括通向网络的控制开销信号,速率一般在64k～1Mb/s之间。ADSL信号和基本音频电话信号（4KHz以下）通过普通电话业务分离器无源耦合到普通电话线上,即使ADSL系统出现故障,也不会影响普通电话业务。ADSL能够传送如此高的速率,主要是采用了先进的调制技术,DMT调制是ADSL现行的国际标准。其主要原理是将传输信道分为256个正交子信道（即使用多载频同时…     

BCI Competition 2003--Data set IIb: enhancing P300 wave detection using ICA-based subspace projections for BCI applications

An algorithm based on independent component analysis (ICA) is introduced for P300 detection. After ICA decomposition, P300-related independent components are selected according to the a priori knowledge of P300 spatio-temporal pattern, and clear P300 peak is reconstructed by back projection of ICA. Applied to the dataset IIb of BCI Competition 2003, the algorithm achieved an accuracy of 100% in P300 detection within five repetitions.     

通信用光纤可靠性影响因素分析

光纤的可靠性是保证光网络寿命的关键,可靠性由光纤的强度分布和疲劳行为共同决定.应用光纤的强度分布数据和蒙特卡洛方法,分析了筛选强度、应力腐蚀敏感性参数和载荷水平等因素对光纤可靠性的影响.分析结果表明,筛选强度的提高可改善筛选后光纤的强度分布,但同时会导致部分筛选后光纤的强度明显降低;按照基于幂定律理论的光纤疲劳行为模型...     

影响挠性印制板插入损耗的几种因素

文章采用三层板叠构对高频通信用挠性印制板(FPCB)的插损进行测试对比,从制造FPCB的材料种类、材料厚度、胶层厚度、仿真设计、信号线过孔类型、盲孔质量,以及信号线阻抗值大小等多个因素总结出对最高频率到20GHz信号插损的影响.     

A study of factors affecting the performance of continuously pumped doubly resonant optical parametric oscillator

The performance characteristics of a continuously pumped doubly resonant optical parametric oscillator have been studied in detail. Using barium sodium niobate as the nonlinear material threshold for oscillation, as low as 3 mW has been observed. At higher pump power levels an efficiency exceeding 50 percent and a tunable output power of nearly 80 mW (signal plus idler), have been achieved. The effect of frequency stability of the pump on oscillator performance has been studied with single-mode operation and ±20-percent amplitude stability attained. The effects of cavity-length perturbations on oscillator performance have also been studied. It is found that cavity-length changes offrac{1}{4}wavelength (250 nm in this case) can produce tunability of the output frequency by as much as 100 cm^-1. These results as well as their interpretation and implications on the design of doubly resonant optical parametric oscillators are discussed.     

A study on the key factors affecting the electronic properties of monocrystalline silicon solar cells

The model of monocrystalline silicon solar cells is established,and the effects of wafer parameters,such as the p-Si（100） substrate thickness,the defect density,and the doping concentration,on the electronic properties of monocrystalline silicon solar cells are analyzed.The results indicate that the solar cells with an Al back-surface-field will have good electronic properties when the wafers meet the following three conditions：（i） the defect density is less than 1.0×1011 cm^-3;（ii） the doping concentration is from 5×10^15 cm^-3 to 1×10^17 cm^-3,i.e.the bulk resistivity is from 0.5 Ω·cm to 10 Ω·cm;（iii） the cells substrate thickness is in the range of 100 μm to 200 μm.