Internal and External Dimensions of Computer Self-Efficacy: An Empirical Examination

Researchers have found computer self-efficacy (CSE) to be important to technology adoption. Past research has treated CSE as a unitary concept. This paper proposes that CSE has two dimensions—internal and external. The idea that CSE has internal and external dimensions is based on attribution theory, which identifies the human tendency to attribute events to causes that are either internal or external to the self. The internal CSE dimension focuses on how individuals perceive their capacity to use computers independently (i.e., without help). The external CSE dimension focuses on how individuals perceive their ability to use computers with human assistance and other forms of external support. Using items drawn from the Compeau and Higgins’ CSE instrument, this paper examines each dimension's relationship to computer anxiety and perceived ease-of-use of information technology. The paper also reports on six studies that examine this proposal, and contributes to the literature by identifying two distinct CSE dimensions, developing theory-driven explanations for their relationships to constructs within the CSE's nomological network, and empirically establishing that they have distinct effects. Implications for research and practice are presented.      

Nanometric ultracapacitors fabricated using multilayer of conducting polymers on self-assembled octanethiol monolayers

Symmetric ultracapacitors have been fabricated considering nanometric 3-layered films made of alternated layers of poly(3,4-ethylenedioxythiophene) (external and internal layers) and polypyrrole (intermediate layer) deposited on steel uncoated and coated with octanethiol self-assembled monolayer. The highest electrochemical and capacitance parameters (i.e. electroactivity, doping level, stored charge, specific capacitance, Coulomb efficiency, energy density and power density) correspond to the ultracapacitor derived from the assembly of 3-layered films deposited on pre-treated steel. Thus, the interface separating the octanethiol monolayer and the most internal layer of the 3-layered film produces a very favorable interaction, which promotes important electrochemical benefits similar to those found for the interfaces in conventional multilayered films. Moreover, the pre-treatment of the steel electrode enhances the roughness and porosity of the film deposited on it, transmitting this effect layer-by-layer. Structural and morphological characteristics, which have been characterized using scanning electron microscopy and atomic force microscopy, have been related with the electrochemical and capacitance properties of the ultracapacitors.     

黄果酸浆花萼发育的形态解剖学观察

黄果酸浆（ Physalis alkekengi L． var． francheti Mast．）为茄科（ Solanaceae）酸浆属（ Physalis）多年生草本植物,因宿存膨大的花萼这种新颖结构,引起了人们对其的广泛关注。对酸浆不同发育时期的花萼进行形态学、表面微形态学和解剖学观察,结果表明：（1）在蕾期花萼生长较为明显,开花期间不再生长,而在果实发育期迅速膨大;（2）花蕾期花萼具表皮毛,但盛花期时完全退化;（3）发育过程中内外表皮细胞大小、形状均发生明显变化,但内外表皮特点有所不同;（4）萼片由表皮、叶肉、叶脉三部分组成,叶肉更倾向于海绵组织的特点,主脉发达,具双韧维管束。本文观察其花萼发育的动态过程,为花器官发育的分子机制研究提供形态解剖学依据。     

硬序重寄生(Phacellaria rigidula Benth.)花形态的扫描电境观察

扫描电境下 ,对硬序重寄生花的外部形态进行了观察。结果表明 ,硬序重寄生一鳞片叶腋内的簇生花发生时 ,首先同时出现大小几乎相同的 2个单花幼花 ;花被片外表面有许多较均匀分布的小乳突 ;每朵花的小苞片常为 3片 ,小苞片呈宽窄不等的三角形 ,其边缘因有较长绒毛而呈流苏状 ;成熟花药各有 2条室裂 ;花粉粒很小 ,具 3孔沟 ,表面无其它明显饰纹     

7种云杉属树种花粉形态特征及其系统学的意义

通过扫描电镜观测了云杉属7个种的花粉形态,运用数据统计和图片分析的方法对花粉形态进行对比研究.结果显示:云杉属7个种的花粉大小变动范围为84.59～103.18 μm,均属于两气囊松科花粉;花粉体近极面与气囊过渡明显,形成帽沿;气囊表面纹理较平滑,在种间变异不显著.萌发沟位于花粉体远极面两气囊之间,呈现沟痕的形式.根据...     

Water Vapor Profiling From CoSSIR Radiometric Measurements

Previous water vapor profiling by millimeterwave radiometry using the 183-GHz absorption line is generally limited to an altitude range of 0-11 km. The additional measurements at the frequencies of 380.2 0.8, 380.2 1.8, 380.2 3.3, and 380.2 6.2 GHz by the new airborne compact scanning submillimeterwave imaging radiometer (CoSSIR) reported in this paper can extend this profiling capability up to an altitude of about 15 km. This is demonstrated by recent CoSSIR measurements onboard the NASA WB-57 aircraft in a flight from Texas to Costa Rica on January 14, 2006. Retrievals of water vapor mixing ratio were performed at eight altitudes of 1, 3, 5, 7, 9, 11, 13, and 15 km from the CoSSIR data set acquired at observational angles of 0 and 53.4. The results were compared with other available measurements from near-concurrent satellites. A very good agreement was found between the collocated values of total precipitable water (TPW) derived from the CoSSIR-retrieved water vapor profiles and those estimated from Tropical Rainfall Measuring Mission Microwave Imager; the average TPW differences range between 0.30 and 0.64 cm, depending on CoSSIR's observational angles. The accuracy of the retrievals was inferred from an analysis of inflight CoSSIR radiometric signal fluctuations.     

Cognitive fit between conceptual schemas and internal problem representations: the case of geospatio-temporal conceptual schema comprehension

Geospatio-temporal conceptual models provide a mechanism to explicitly represent geospatial and temporal aspects of applications. Such models, which focus on both "what" and "when/where," need to be more expressive than conventional conceptual models (e.g., the ER model), which primarily focus on "what" is important for a given application. In this study, we view conceptual schema comprehension of geospatio-temporal data semantics in terms of matching the external problem representation (that is, the conceptual schema) to the problem-solving task (that is, syntactic and semantic comprehension tasks), an argument based on the theory of cognitive fit. Our theory suggests that an external problem representation that matches the problem solver's internal task representation will enhance performance, for example, in comprehending such schemas. To assess performance on geospatio-temporal schema comprehension tasks, we conducted a laboratory experiment using two semantically identical conceptual schemas, one of which mapped closely to the internal task representation while the other did not. As expected, we found that the geospatio-temporal conceptual schema that corresponded to the internal representation of the task enhanced the accuracy of schema comprehension; comprehension time was equivalent for both. Cognitive fit between the internal representation of the task and conceptual schemas with geospatio-temporal annotations was, therefore, manifested in accuracy of schema comprehension and not in time for problem solution. Our findings suggest that the annotated schemas facilitate understanding of data semantics represented on the schema.     

On the analysis of slotted waveguide arrays

A strategy for the full-wave analysis of slotted waveguide planar arrays is presented and demonstrated. The core of the method is a suitable segmentation of the antenna into two fundamental regions: an "internal" one, formed by the waveguide circuit, and the "external" one, consisting of the half space above the plate where the radiating slots are located. The internal region is further segmented into several blocks, connected to each other via their generalized admittance matrices (GAMs). The latter are calculated by means of either a commercial or a home made tool. The front plate is considered as a whole and analyzed by the moment method, in terms of modes of the slots. The latter are considered as short sections of waveguide whose length is just the conductor thickness, connecting the internal and external regions. The approach has been applied with success to a number of large planar arrays, both in rectangular and ridge waveguide.     

A simulation of the SA node by a phase response curve-based model of a two-dimensional pacemaker cells array

This paper presents a simulation of the sino-atrial (SA) node by a two-dimensional pacemaker cells array model, based on phase response curve (PRC) interaction. This simple model of the cardiac pacemaker cells, involves only the most basic functional properties, which play a direct role in the determination of the SA node rhythm. The two most relevant functional properties of the pacemaker cells are: The intrinsic cycle length, an "internal" feature of each pacemaker cell, and the PRC, an "overall collective" function. The PRC contains the "information" about the type of interactions of each pacemaker cell with the outside world (i.e., interaction with neighboring cells, external stimulus, etc.), and "strength" of the interaction (strong, weak, etc.). We studied the spatial interaction among a large number of pacemaker cells (15 x 15), as a function of the regional variation of cells properties, the "electrical" coupling between cells (the PRC), and the appearance of regions with abnormal cycle lengths. We investigated the influence of those parameters on the mutual interaction between the pacemaker cells, on the activation pattern and conduction time of the array, and on a pseudo-electrocardioigram (ECG) signal. This study demonstrates that by representing the pacemaker cells in the SA node by only two fundamental features, and by applying a simple physical-mathematical model, we can create a global picture of the SA node system. This enables us to explore physiological phenomena related to the genesis and maintenance of the SA node activity, and to gain insight into the conditions which predispose the SA node instability, and conduction disturbances.     

光学定位系统中摄像机标定的研究

在被动式光学定位系统中,CCD摄像机的标定是一个极其重要的过程。CCD摄像机的标定过程实际上是求解摄像机内、外参数的过程。基于基本矩阵的摄像机标定方法是根据极线约束、本质矩阵以及基本矩阵之间的关系,利用传统的8点算法得到基本矩阵的初始值,再通过其他匹配点迭代计算摄像机的径向阶畸变和切向畸变系数,最后由得到的畸变系数值计算校正后的基本矩阵,从而实现对畸变图像进行校正。     

On the exponential formula for reliability

It is usually assumed that the exponential formula commonly used in reliability & survival analysis holds for the case of conditioning on "smooth" external covariates, and is not valid for the case of internal covariates. Using an example of external shocks affecting an item, it is shown that, though formally the influence is not smooth in this case, the corresponding exponential formula still holds. On the other hand, internal covariates do not necessarily lead to the not-absolutely-continuous conditional Cdf. If the internal covariate process specifies the full information on the item's failure process, then the corresponding conditional Cdf is not absolutely continuous. If the observed internal covariate does not provide complete information on the item's state, then the corresponding conditional Cdf can be still absolutely continuous, and the exponential formula holds.     

Switchable Faraday shielding with application to reducing the pain of internal cardiac defibrillation while permitting external defibrillation

Switchable Faraday shielding is desirable in situations where electric field shielding is required at certain times and undesirable at other times. In this study, electrostatic finite element modeling was used to assess the effect of different shield geometries on the leakage of an internally applied field and penetration of an externally applied field. "Switching OFF" the shield by electrically disconnecting shield faces from each other was shown to significantly increase external field penetration. Applying this model to defibrillation, we looked at the effect of spacing and size of shield panels to maximize the ability to deliver an external defibrillation shock to the heart when shield panels are disconnected while providing acceptably low leakage of internal defibrillation shocks to avoid painful skeletal muscle capture when shield panels are connected. This analysis may be useful for designing internal defibrillator electrodes that preserve the efficacy of internal and external defibrillation while avoiding the significant morbidity associated with painful defibrillator shocks. Similar analysis could also guide optimizing the switchable Faraday shielding concept for other applications.     

A biped walking robot capable of moving on a vertical wall

The use of a wall-climbing robot for purposes such as rescue, wall inspection and fire-fighting on high-rise buildings has been anticipated for a long time. Three different types of wall-climbing robots have been developed in Japan. The first one has a large area sucker, which has the reverse mechanism of a hovercraft. This type can be used only on flat and wide surfaces. The second one has crawlers to move on a vertical wall with many small suckers on them. The third one has a walking mechanism with small suckers on each foot. A biped walking model was built and tested on a vertical wall and a ceiling. The aerodynamic matching between blower performance and required forces of a sucker, as well as the control systems of the robot, are studied in detail.     

关系型数据库的数据依赖及应用程序设计

数据依赖是关系型数据库数据之间的内在联系，在数据库规范化设计中数据依赖起着重要的作用。数据依赖的主要类型是函数依赖，函数依赖分为完全函数依赖、部分函数依赖和传递函数依赖。在实际应用中数据依赖又包括简单函数依赖和复杂函数依赖、内部依赖关系和外部依赖关系。为阐明这些数据依赖关系的概念和应用，引入一个“物业收费管理系统”的实例，介绍关系型数据库中数据依赖在实际应用中的设计方法，以及内部依赖关系和外部依赖关系在该应用实例中的程序设计过程。     

Profit evaluation of a two-unit system with internal and external repairs, inspection and post repair

In practice, systems do not always fail with a major breakdown, needing a heavy repair from some external source. Quite often, systems have a minor fault for which an immediate internal repair is more appropriate, in terms of availability of the system and economy, than calling a repairman from some external repair facility, waiting idly for his arrival or making a call with a higher cost. The present work discusses two non-identical unit systems with two types of repair, the internal and the external one. The external repair is called only when the internal staff fail to do the job. In the case of external repair, there is a provision of inspection, wherein if the repair is found unsatisfactory, it is sent for post repair. Using the regenerative point technique, various reliability characteristics of system effectiveness have been obtained.     

一种三端可调电压基准设计

文章提出了一种基于传统带隙基准电压源,具有良好热稳定性的三端可调分流电压片外基准源,利用内部2.5V的基准电压,使用分压电阻对输出形成深度负反馈,使输出电压可以稳定在2.5V～30V宽范围内调节。用4μm 45V Bipolar工艺,利用Cadence Spectre工具来仿真,在宽范围负载电流条件下,输出电压连续可调,并且具有很好的温度特性。     

A technique for regional analysis of femorotibial cartilage thickness based on quantitative magnetic resonance imaging

The objective of this work was to develop a methodology for measuring cartilage thickness in anatomically based subregions in the tibial and in the central weight-bearing femoral cartilage from magnetic resonance (MR) images. The tibial plateau was divided into a central area of the total subchondral bone area (tAB), and anterior, posterior, internal, and external subregions surrounding it. In the weight-bearing femoral condyles, central, internal, and external subregions were determined. The Euclidean distance between the tAB and cartilage surface was used for determining cartilage thickness. The reproducibility of the method was evaluated on test-retest data sets of 12 participants (six healthy, six with osteoarthritis). The subregion size was varied systematically to study the influence on the reproducibility. The size of the subregions was highly consistent under conditions of repositioning (standard deviation 0.0%-0.3%). The precision errors for regional mean cartilage thickness measurements ranged from 19 mum (1.5%) to 84 mum (4.7%). The computation of regional cartilage thickness values from segmented MR images is shown to be highly reproducible and robust under conditions of joint repositioning. In longitudinal studies, this technique may substantially enhance the ability of quantitative MRI to monitor structural changes in osteoarthritis at narrow time intervals.     

Sidewinder: Defense in depth using type enforcement

Sites use firewalls to defend against external attacks while providing necessary Internet services. Firewalls make a site safer: They present a smaller risk since they provide fewer services. However, most firewalls use standard computer operating systems. This can allow an attacker to overrun the firewall if a known security flaw is present. The Sidewinder(TM) firewall system overcomes this problem using type enforcement. Network server applications operate in independently controlled compartments called domains, each granted specific permission to access particular types of files or communicate with other domains. If a server succumbs to an attack, type enforcement restricts the amount of damage an attacker can do. In particular, Sidewinder prevents an attack on an Internet server from accessing domains serving internal, protected networks. An attacker cannot overrun a Sidewinder because the type enforcement restrictions cannot be disabled while the system is handling network traffic.     

构建时间、空间、网络层次端到端安全网络

针对目前IP网对安全的新要求,华为提出了“i^3安全”解决方案．即时间、空间、网络层次三个纬度端到端集成安全体系架构。此方案所具有的特色包括：在时间上,同时关注网络的事前防范和事后跟踪能力;在空间上,针时外网与内网的不同特点制定有效的安全策略;在网络层次上,分别根据网络层、用户接入层和业务层的特点进行有针对性的防范。     

Discrete Repairable Systems With External and Internal Failures Under Phase-Type Distributions

We study a multi-component system subject to internal, and external failures. The external failures may be repairable, or not. The unit enters the repair channel when a repairable failure occurs and there is a repairman available. The random times involved in the study of the system are phase-type distributed. From this system, new ones are developed. General systems with internal, and external repairable, or non-repairable failures are built, generalizing the initial system. The availability, and the conditional probability of failure for the different types of failures and systems are calculated for finite, and infinite numbers of units. The results are implemented computationally with Matlab, and illustrated using examples.