共查询到20条相似文献，搜索用时 15 毫秒
1.
Jae‐Hyun Jung Keehoon Hong Gilbae Park Indeok Chung Byoungho Lee 《Journal of the Society for Information Display》2010,18(7):527-534
Abstract— A 360°‐viewable cylindrical three‐dimensional (3‐D) display system based on integral imaging has been implemented. The proposed system is composed of a cylindrically arranged electroluminescent (EL) pinhole film, an EL film backlight, a barrier structure, and a transmission‐type flexible display panel. The cylindrically arranged point‐light‐source array, which is generated by the EL pinhole film reconstructs 360°‐viewable virtual 3‐D images at the center of the cylinder. In addition, the proposed system provides 3‐D/2‐D convertibility using the switching of EL pinhole film from a point light source to a surface light source. In this paper, the principle of operation, analysis of the viewing parameters, and the experimental results are presented. 相似文献
2.
IS researchers have normally assumed that satisfaction is the key factor influencing IS customers’ reuse of services; however, a focus on customer satisfaction does not always guarantee customer retention. We synthesized customer satisfaction and dissatisfaction models from prior service quality research to provide a comprehensive model predicting the behavioral intentions of customers to reuse IS services. Five research hypotheses were empirically tested by using a field study of 263 users of an IS service department. Our findings placed IS service quality in a causal network leading to IS service reuse and highlighted the relative importance that service quality value played in predicting behavioral intention to reuse the service. 相似文献
3.
Exploitation of the NP hard, mixed µ problem structure provides a polynomial time algorithm that approximates µ with usually reasonable answers. When the problem is extended to the skew µ problem an extension of the existing method to the skew µ formulation is required. The focus of this paper is to extend the µ lower bound derivation to the skew µ lower bound and show its direct computation by way of a power algorithm. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
4.
Given increasing investment in an IT (information technology) artifact (i.e., online service website), it is becoming important to retain existing customers. In order to help link website design and investment decisions to the strategy for retaining customers, we propose a model by extending the user satisfaction perspective into research on online service continuance. We empirically tested the model within the context of a social network service. The analysis results found that website information satisfaction and system satisfaction play key roles in forming continuance intention through perceived usefulness and perceived enjoyment. It is also noted that computer anxiety serves as an important moderator toward continuance intention. Theoretical and practical implications are offered for better understanding of the role of the IT artifact in online service post-adoption phenomena. 相似文献
5.
研究了在上海医疗保险信息系统这样重要信息系统建立信息安全体系的方法,探索了适合我国国情和行业特点的信息安全管理方法和标准,对信息安全标准本地化进行了探索和实践,为建立我国的信息安全管理标准提供了参考。 相似文献
6.
In this paper, a 180° hybrid consisting of a broadband balun and a T‐junction in‐phase power divider is proposed. The 180° hybrid is intended for operation in the C‐band. The balun resembles a center tapped magnetic transformer where the coils are replaced by broadside‐coupled lines. This new technique allows magnetic couplers to be realized by planar structures at microwave frequencies. The planar balun is broadband, and the size reduction is considerable. The broadside‐coupled lines are on a suspended substrate. The proposed structure can be used in the beam forming networks of the multiple‐beam antennas. It also prevents cross connections in the conventional beam forming networks. The planar balun is analyzed by the signal flow graph method. The scattering parameters of the 180° hybrid are calculated by the multiport connection method. Some design formulas for the construction of the balun are presented. The 3‐dimensional model of the planar 180° hybrid is simulated by a full‐wave simulator. Measurement results of the fabricated hybrid approve the simulation results. The 180° hybrid exhibits a relative bandwidth of 45% centered at 4.5 GHz. In the operating band, the amplitude and phase imbalance of the output ports are <0.6 dB and <10°, respectively. 相似文献
7.
Organisations have invested in self‐service information systems (IS) to provide a direct interface for service delivery. Enriching the usage of these systems can provide organisations with immense benefits. However, limited research has been directed towards understanding post‐adoption IS usage behaviour in general and specifically in the context of self‐service IS. This study proposes post‐adoption IS usage behaviour as a broader concept constituting feature level usage of IS, integration of IS in the work system and exploration of new uses of IS. We evaluate how the new conceptualisation can be used to classify users at different stages of self‐service IS usage. Further, we examine user perceptions that differentiate among the users situated at different self‐service IS usage stages. Data were collected in the context of a self‐service Web‐based IS to validate the post‐adoption IS usage constructs and to examine the proposed thesis. The newly developed conceptual structure and measures for post‐adoption IS usage behaviour exhibit strong psychometric properties. The analysis shows three distinct post‐adoption IS usage stages and highlights that usefulness, user‐initiated learning, ease of use, satisfaction and voluntariness of use differentiate users at the different stages of post‐adoption IS usage. The results show that these variables aggregate into value confirmation and learning orientation as two higher‐level concepts. Further, we evaluate the predictive efficacy of the research model in classifying users into different post‐adoption self‐service IS usage stages. Implications are drawn for future research. 相似文献
8.
We present a non‐trivial case study designed to highlight some of the practical issues that arise when using mixed‐µ or complex‐µ robust synthesis methodologies. By considering a multi‐input multi‐output three‐cart mass–spring–dashpot (MSD) with uncertain parameters and dynamics, it is demonstrated that optimized performance (disturbance‐rejection) is reduced as the level of uncertainty in one or two real parameters is increased. Comparisons are made (a) in the frequency domain, (b) by RMS values of key signals and (c) in time‐domain simulations. The mixed‐µ controllers designed are shown to yield superior performance as compared with the classical complex‐µ design. The singular value decomposition analysis shows the directionality changes resulting from different uncertainty levels and from the use of different frequency weights. The nominal and marginal stability regions of the closed‐loop system are studied and discussed, illustrating how stability margins can be extended at the cost of reducing performance. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
9.
Pierre Apkarian 《国际强度与非线性控制杂志
》2011,21(13):1493-1508
》2011,21(13):1493-1508
We revisit robust complex‐ and mixed‐ µ‐synthesis problems based on upper bounds and show that they can be recast as specially structured controller design programs. The proposed reformulations suggest a streamlined handling of µ‐synthesis problems using recently developed (local) nonsmooth optimization methods, where both scalings or multipliers and a controller of given structure are obtained simultaneously. A first cut of the nonsmooth programming software for structured H∞ synthesis is made available through the MATLAB R2010b Prerelease, Robust Control Toolbox Version 3.5 developed by The MathWorks, Inc. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
10.
This paper considers the application of the skewed structured singular value to the robust stability of systems subject to strictly real parametric uncertainty. Three state‐space formulations that counteract the discontinuous nature of this problem are detailed. It is shown that the calculation of the supremum of the structured singular value over a frequency range using these formulations transforms into a single skewed structured singular value calculation. Similar to the structured singular value, the exact calculation of the skewed structured singular value is an NP‐hard problem. In this work, two efficient algorithms that determine upper and lower bounds on the skewed structured singular value are presented. These algorithms are critically assessed using a series of robustness analysis tests on a safety‐critical experimental drive‐by‐wire vehicle. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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12.
《Information & Management》2016,53(4):447-466
Information technology (IT) organizations use strategic IT benchmarking (SITBM) to revise IT strategies or perform internal marketing. Despite benchmarking's long tradition, many SITBM initiatives do not reveal the desired outcomes. The vast body of knowledge on benchmarking and IT management does not help overcome the challenges of successful SITBM. We therefore synthesize the existing research on IT management and benchmarking into a concept relationship map and derive future research avenues. We find that there is much literature on how to obtain SITBM results. However, research does not explain how these results are transformed into outcomes – essentially the problem many practitioners struggle with. 相似文献
13.
A resonator technique is used to investigate the validity of microstrip t-junction and 45° bend discontinuity models over the frequency range 18–60 GHz. Models are checked against both experimental results and electromagnetic simulations using a previously described dual-resonator method to eliminate confounding variables. The method has been improved to provide results in terms of model phase error rather than a dimensionless validation parameter. Model phase errors in excess of 15° have been found. © 1998 John Wiley & Sons, Inc. Int J RF and Microwave CAE 8: 42–48, 1998. 相似文献
14.
Web服务可信证据收集与评估机制研究 总被引：1，自引：0，他引：1
现有Web服务的可信评估机制大多忽视Web服务使用者及应用场景的差异性,其评估结果的准确性无法得到保证。提出了一种基于可信证据的Web服务可信评估机制,实现了可信证据的Web服务调用主动探测、服务容器自动反馈和用户反馈收集,同时提出了一种基于用户反馈的上下文敏感可信评估方法,全面考虑了Web服务质量属性的上下文相关性,进一步提高了Web服务可信评估的准确性。 相似文献
15.
《Displays》2020
This study examines the essential effects of visual feedback on users’ perceptions of time and on their evaluations of waiting time for a mobile application user interface. The two variables adopted in this experiment are wait indicator visual feedback and waiting time. Three types of visual feedback were used: bar indicator, pie indicator, and cartoon indicator. Three waiting times were used: 2 s, 5 s, and 10 s. This study was conducted based on the attentional-gate model of Zakay and Block to help investigate user time perceptions. The experiment of this study was a 3 × 3 mixed factorial design to measure the impact of the research variables on the users’ perceptions of waiting time, wait evaluations, and preferences. Results showed that the users’ time perceptions and wait evaluations were affected by the feedback types and waiting times, and the results are consistent with Vierordt's law and the attentional-gate model. Furthermore, there was a positive impact on the participants' preferences when they perceived a shorter waiting time. The cartoon type feedback can help reduce the perception of waiting time, but it does not necessarily improve user experience regarding short waiting time. 相似文献
16.
Abstract. Information systems evaluation has strong social and organizational dimensions while existing research focuses primarily on the formal and positivistic characteristics. We investigate the organizational roles of the key stakeholders within the particular evaluation context (orientation). We focus on four evaluation orientations: control, sense-making, learning and exploratory. Experience from a case study is used to analyse these concepts and relations. The case organization attempted to move from a state of an ad-hoc evaluation practice to a more business-driven one. New tools, processes, roles and responsibilities were developed during the attempt. We examine the behavioural and organizational integration aspects of evaluation during that journey. 相似文献
17.
Web服务技术使开放环境中的大规模应用得到不断发展,服务提供商提供了不计其数的具有相同或类似功能的Web服务,如何选择适合的尤其是可信的Web服务是个难题。目前大多数服务选择机制都设计固定的因素集作为选择标准,但是在处理一些未知的Web服务时,难以满足用户的多样性需求。基于此,从社会网络的视角综合考虑了服务提供商网络和用户网络两个方面,提出了可信服务选择框架,对服务提供商采用模糊综合评价法来确定其综合评价值,基于用户声望评价来确定单个Web服务的可信度。用户依据服务质量(Quality of Service,QoS)需求、得到的QoS数据、服务提供商的综合评价和Web服务的可信度进行Web服务的选择。 相似文献
18.
孙素云 《计算机工程与设计》2008,29(9):2259-2262
对Web服务的信誉度、信誉关系属性和信任类型进行了形式化的定义,并据此来评估Web服务的信誉行为,考虑到Web服务信誉度的不确定性,在引入信誉量化概念的基础上,对现有的UDDI规范进行扩展,提出了Web服务信誉度评估模型,并深入研究了Web服务的信誉度评估方法及模型的实现方案,与其它的Web服务信誉度模型相比,该模型通过使用客户反馈、主动监视的机制以及采用第三方权威机构评价Web服务的信誉度,从而保证了信誉度的公平性和有效性. 相似文献
19.
The goal of this study is to investigate the impact of simple, system-generated visual feedback on motivations to contribute knowledge to community-based crowdsourcing. Various kinds of visual feedback (status, rank contrast, average assimilation, and top assimilation) were created based on social comparison theory and cognitive evaluation theory. In addition, motivation to contribute knowledge over time was investigated. A total of 280 individuals participated in the experiment. The study found that 1) the rank contrast group completed less tasks than the control group, 2) the rank contrast and status group exhibited lower willingness to contribute than the control group, 3) participants who completed all tasks showed increased willingness to contribute over time, and 4) among participants who completed all tasks, social comparisons focused on achievable target goals resulted in greater willingness to further contribute knowledge over time. These findings provide theory-based, empirical support for the potential of external interventions such as visual feedback to influence willingness to contribute and sustain knowledge sharing. 相似文献
20.
Radio frequency energy harvesting (RFEH) circuits can convert the power of communication signals from radio frequencies (RF) in the environment into direct current and voltage (DC power). In this study, the Greinacher full‐wave rectifier circuit topology was combined with a 180° hybrid ring (rat‐race) coupler which was a passive RF/microwave circuit. Thus, higher RF‐DC conversion efficiency was obtained. First, using the Greinacher rectifier topology, RFEH circuit operating at the center frequency of 1850 MHz was designed. Then, at this frequency, designing of the rat‐race coupler having 1000 MHz bandwidth was made. The S‐parameter measurements and simulation data of the designed coupler circuit were compared. Finally, the high efficiency rectifier circuit where these two circuits were used together was designed. The proposed rectifier circuit was constructed on 70 × 70 × 1.6 mm3 FR4 substrate material with a permittivity of 4.3 (εr = 4.3). The power conversion efficiency (PCE) of the rectifier circuit, which had 125 MHz bandwidth at the center frequency of 1850 MHz and was developed with rat‐race coupler, was calculated as 71% at 4.7 dBm input power. In addition, with this study, at ?15 dBm input power, which was a relatively low power level, 40% PCE value was obtained. 相似文献