Complete parasitic‐capacitance‐shell extraction of high‐frequency switch‐HEMT equivalent‐circuit model

This paper presents a new solution to a particular problem of high electron‐mobility transistor (HEMT) equivalent‐circuit modeling, that is, complete parasitic‐capacitance‐shell extraction of high‐frequency single‐gate and dual‐gate switch‐based HEMTs, which is very important to the accuracy of high‐frequency HEMT switch models, but not important in the conventional common‐source HEMT modeling for amplifier‐applications. A full‐wave electromagnetic (EM) analysis based method is proposed to analytically extract the complete parasitic‐capacitance‐shell of single‐gate and dual‐gate switch‐based HEMTs. All the 6 parasitic capacitances of the single‐gate switch‐based HEMT and all the 10 parasitic capacitances of the dual‐gate switch‐based HEMT are extracted by linear equations. No resistance parameter is needed to calculate the capacitance‐to‐ground and the interelectrode‐capacitance, and for the first time, all the 10 parasitic capacitances of the dual‐gate switch‐based HEMT are completely considered and analytically extracted. Then, a consistent and systematic modeling procedure of single‐gate and dual‐gate switch‐based HEMT is verified. With the complete parasitic‐capacitance‐shells extracted, the accurate intrinsic model of the single‐gate HEMT can be directly embedded into the parasitic‐shell of the dual‐gate HEMT. The predicted scattering parameters of the single‐gate and dual‐gate series switches fit well with the measurements up to 40 GHz, and accurate linear scalability are also found.     

Direct extraction method of HEMT switch small‐signal model with multiparasitic capacitive current path

It has been found that the analytical extraction methods cannot be applied to the usual test structure of the switch high electron‐mobility transistor (HEMT) with a large‐value gate grounded resistor. The significant effect of the precise multicapacitive current path on switch model precision has also been found. The multicapacitive current path here is different from the seemingly similar hypothesis proposed for the distributed parasitic effects at high frequencies (eg, D‐band). In fact, for switch based HEMT, it is important to distinguish between the capacitive current paths accurately even at relatively low frequencies. Due to the existing of the large gate resistance, the usual capacitance mix decreases the accuracy of the switch model significantly. Thus an analytical method has been developed to calculate parasitic capacitances (the capacitance to ground and the interelectrode capacitance) through full‐wave electromagnetic analysis. For practical applications and further verification, the whole HEMT switch small‐signal models and the direct extraction methods are presented. The simulated results fit well with the measurements up to 40 GHz.     

Influence of channel‐deposition conditions and gate insulators on performance and stability of top‐gate IGZO transparent thin‐film transistors

Abstract— Amorphous‐oxide‐semiconductor thin‐film transistors (TFTs) have gained wide attention in recent years due to their many merits. In this paper, a series of top‐gate transparent thin‐film transistors (TFTs) based on amorphous‐indium—gallium—zinc—oxide (a‐IGZO) semiconductors have been fabricated and investigated. Specifically, low‐temperature SiNx and SiOx were used as the gate insulator and different Ar/O² gas‐flow ratios were used for a‐IGZO channel deposition to study the influences of gate insulators and channel‐deposition conditions. In addition to the investigation of device performance, the stability of these TFTs was also examined by applying constant‐current stressing. It was found that a high mobility of 30‐45 cm²/V‐sec and small threshold‐voltage shift in constant‐current stressing can be achieved using SiNx with suitable hydrogen‐content stoichiometry as the gate insulator and the carefully adjusted Ar/O² flow ratio for channel deposition. These results may be associated with hydrogen incorporation into the channel, the lower defect trap density, and the better water/oxygen barrier properties (impermeability) of the low‐temperature SiNx.     

A HEMT large‐signal model for use in the design of microwave switching circuits

The nonlinear sources of switch‐HEMTs have been well analyzed by using the measured data. The small signal intrinsic capacitances (under both positive and negative V _ds operation) have been extracted by an extended small signal model. one‐dimension capacitance model has been effectively applied to model the small signal incremental capacitances directly extracted from the key operation region, which has also automatically taken into account the surface trapping effects. A new capacitance model has been effectively proposed to well fit the key nonlinear source (the deep subthreshold capacitance) of switch‐HEMTs. Simple switching function and additional voltage dependence have been applied to model the wide linear‐region (from high‐ V _gs region to deep subthreshold region) of channel current. On/off state small signal insertion loss, small signal isolation, weak harmonics, and power carrying capabilities are accurately predicted by the large signal model. The model shows very good convergence of circuit simulation. Meanwhile, the simple equations and distinguishing among the capacitances accurately make the scaling rules simple and accurate.     

A note on stability, robustness and performance of output feedback nonlinear model predictive control

In recent years, nonlinear model predictive control (NMPC) schemes have been derived that guarantee stability of the closed loop under the assumption of full state information. However, only limited advances have been made with respect to output feedback in the framework of nonlinear predictive control. This paper combines stabilizing instantaneous state feedback NMPC schemes with high-gain observers to achieve output feedback stabilization. For a uniformly observable MIMO system class it is shown that the resulting closed loop is asymptotically stable. Furthermore, the output feedback NMPC scheme recovers the performance of the state feedback in the sense that the region of attraction and the trajectories of the state feedback scheme can be recovered to any degree of accuracy for large enough observer gains, thus leading to semi-regional results. Additionally, it is shown that the output feedback controller is robust with respect to static sector bounded nonlinear input uncertainties.     

The concept of ‘Exponential input to state stability’ for stochastic systems and applications to feedback stabilization

This paper presents a version of the well-known Sontag’s ‘input-to-state-stability’ property for stochastic systems. This concept is used to derive sufficient conditions for global stabilization for certain class of stochastic nonlinear systems by means of static and dynamic output feedback.     

The influence of temperament style on a student’s choice of and performance in a computer programming course

This study is an attempt to determine whether it is necessary to include temperament style when compiling an instrument to predict a student’s chances of success in a computer programming course. Temperament style is seen as the combination of qualities which constitute the natural disposition of an individual and which affect actions, thinking and emotions. The DISC model, as adapted by Boyd [Boyd, C. F. (1994). Different children, different needs: the art of adjustable parenting. Oregon: Questar Publishers Inc.], views people as behaving along two orthogonal dimensions: the speed at which a person moves through life, and his/her general focus when doing things, i.e. on people or on tasks. This study proved that both of these dimensions have an influence on the performance of students in a computer programming course while one of them also has an influence on a student’s choice to pursue a programming course.     

基于SPICE模型参数的二极管选取及应用仿真

在电路的设计及仿真的过程中,常需在元件库装入新元件以便使用.针对其中二极管元件的选取及更新问题.提出直接将SPICE模型参数作为选取依据与其他方法相比更具合理性和实用性.为此,对二极管SPICE模型参数的物理意义予以明确.此外,还介绍了通过修改参数在multisim9.0仿真元件库中编辑新元件的方法.以一款超突变结GaAs变容二极管MV34010为例,将其运用于调谐放大电路中,并采用电路仿真的手段对其工作效果加以检验,理想的仿真效果充分证明了选管方法的可行性.     

The effects of short‐term and long‐term exposure to extreme cold environment on the body’s physiological responses: An experimental study

There is little epidemiological data to make reliable conclusions about the effects of exposure to cold on the body’s physiological responses. The current study aimed to address this lacuna in the available research. The study sample consisted of 50 outdoor mechanic workers as a case group and 15 staff members as a control group used in the outdoor automechanic workshops. Air environmental factors, including dry‐bulb temperature and air velocity, were measured by the portable hot wire thermo anemometer in the workstation of each subject. The body’s physiological responses were also measured during daily activities in accordance with ISO 9886. Using Semmes–Weinstein monofilament, touch sensory tests were conducted for determining hands’ sensorineural functions. The baseline measurements showed the mechanic workers had lower finger sensation levels and finger skin temperatures than the control group (p < 0.05). This may be attributed to long‐term exposure to acute cold air during cold seasons. However, after short‐term exposure to extreme cold environment, the mechanic workers showed lower losses in finger skin temperatures and finger sensation levels than the control group ( p < 0.05). The findings confirmed that prolonged localized cold exposure among mechanic workers can result in localized habituation of vasoconstrictor responses.     

The influence of electric fields on nanostructures—Simulation and control

Macroscopic electric fields may be used to influence or even control the shape evolution of single layer islands on a crystalline surface. We validate a phase-field approach to simulate such shape evolutions by comparison with simulations based on a sharp interface approach. The phase-field model is then used to formulate and discretize the control problem of finding an electric field which drives an island to a predefined shape. Some first results of this approach are presented.     

The influence of people’s culture and prior experiences with Aibo on their attitude towards robots

This paper presents a cross-cultural study on peoples’ negative attitude toward robots. 467 participants from seven different countries filled in the negative attitude towards robots scale survey which consists of 14 questions in three clusters: attitude towards the interaction with robots, attitude towards social influence of robots and attitude towards emotions in interaction with robots. Around one half of them were recruited at local universities and the other half was approached through Aibo online communities. The participants’ cultural background had a significant influence on their attitude and the Japanese were not as positive as stereotypically assumed. The US participants had the most positive attitude, while participants from Mexico had the most negative attitude. The participants from the online community were more positive towards robots than those not involved. Previous experience in interacting with Aibo also had a positive effect, but owning an Aibo did not improve their attitude.     

The effect of role conflict on self‐disclosure in social network sites: An integrated perspective of boundary regulation and dual process model

As people increasingly integrate social network sites (SNSs) into their daily lives, their social connections on SNSs become more diverse, including their friends, co‐workers, and relatives. In such a context, users may receive different role expectations from their various social circles and experience role conflict in their usage of SNSs. Furthermore, previous literature suggests that people may not always make privacy‐related decisions through effortful and deliberate information processing. Drawing on the perspective of boundary regulation and dual process theories, this study clarifies the consequences of role conflict on SNSs. A theoretical model is developed to examine the effect of role conflict regarding privacy risk and perceived control, which, in turn, impact self‐disclosure behaviour, as well as how this process is moderated by high‐ versus low‐effort processing. The results of 4 experiments provide strong support for our model. The implications for theory and practice are discussed.     

改进RWP移动模型结合线性规划的无线网络能量均衡算法

针对无线网络中大多数现有方法不能很好地兼顾能量效率和能量均衡的问题,提出了基于改进随机路点移动模型(random waypoint mobility models,RWP)结合线性规划(linear programming, LP)的无线网络能量平衡模型。首先,使用方形网络拓扑和RWP生成移动性场景;然后,在最优路由条件下建模网络行为并构建了一种LP架构;最后,利用优化问题的全局知识获得了该架构的高效解。数值分析结果表明,移动性对无线节点的能量耗散趋势具有显著影响,移动性可提高能量平衡达到某一级别,但极端的移动性可能会导致无线网络能量平衡的劣化。     

The influence of color grouping on users’ visual search behavior and preferences

The article investigates how the various colors and color pairs used as grouping factors affect the visual search process and direct manipulation activities in the context of toolbar-like graphical panels. Red, green, and blue colors having the same perceptual distance in the CIELab space are used. The results demonstrate significant influence of the examined color-related factors on the speed and accuracy. The color preattentive property depends strongly on the grouping pattern: layouts with smaller colored areas were operated worse than panels divided into larger parts. Meaningful differences were also observed between panels with single and two colored backgrounds.     

The influence of user interaction and participation in social media on the consumption intention of niche products

Social media may be particularly adept at promoting niche products because of the tendency of consumers to participate in generating reviews and discussing such products, thereby raising interest in them. In this study, we investigate how patterns of user interaction in discussing a niche cultural product may influence participation levels, which in turn enhance consumption intentions. We show that higher levels of participation can indeed enhance consumption intention. Furthermore, interaction patterns with high inclusiveness and betweenness centralization may enhance participation levels, whereas out-degree centralization and core-periphery have a detrimental influence. Implications for research and practice are discussed.     

The effect of nonhuman’s external regulation on young children’s creative thinking and thinking aloud verbalization during learning mathematical tasks

The present study was conducted to explore the effect of nonhuman’s external regulation on children’s natural development process of creative thinking, the degree of the manifested creative thinking, the influence of children’s verbalization on their creative thinking, and the extent the stimulus material was usable for children during learning math tasks. The Aginian’s methodology (, , ,  and ) that relied on an isolated, computer-based learning system that acts as a standalone learning environment, with special child-simple-calculator was used by 100 healthy preschool children. The results showed that children were fluctuated between negative and positive creative thinkers, children’s verbalization has no effect on their creative thinking, and the relation between the children’s verbalization of thinking aloud and their creative thinking is a reverse relationship. The usability analysis concluded that, fun is not a key element of the usability as it can only be a feature that could facilitate usability. The mathematical analysis showed that the computer, as a nonhuman external regulator, can integrate the net signed of children’s creative thinking through embedding mathematics integration.     

The effect of communication and synchronization on Amdahl’s law in multicore systems

This work analyses the effects of sequential-to-parallel synchronization and inter-core communication on multicore performance, speedup and scaling from Amdahl’s law perspective. Analytical modeling supported by simulation leads to a modification of Amdahl’s law, reflecting lower than originally predicted speedup, due to these effects. In applications with high degree of data sharing, leading to intense inter-core connectivity requirements, the workload should be executed on a smaller number of larger cores. Applications requiring intense sequential-to-parallel synchronization, even highly parallelizable ones, may better be executed by the sequential core. To improve the scalability and performance speedup of a multicore, it is as important to address the synchronization and connectivity intensities of parallel algorithms as their parallelization factor.     

Applying the Practical Inquiry Model to investigate the quality of students’ online discourse in an information ethics course based on Bloom’s teaching goal and Bird’s 3C model

The goal of this study is to better understand how the study participants’ cognitive discourse is displayed in their learning transaction in an asynchronous, text-based conferencing environment based on Garrison’s Practical Inquiry Model (2001). The authors designed an online information ethics course based on Bloom’s taxonomy of educational objectives and Bird’s 3C model (Content–Construction–Consolidation). The content analyzed included the participants’ message posts, the quality of the dialogue and the scaffolding strategies for mentoring used by group leaders and teachers.     

The influence of online store beliefs on consumer online impulse buying: A model and empirical application

Our study provides insight into the relationships between online store beliefs and consumer online impulse buying behavior. Drawing upon cognitive emotion theory, we developed a model and showed how beliefs about functional convenience (online store merchandise attractiveness and ease of use) and about representational delight (enjoyment and website communication style) related to online impulse buying. The model was tested using survey data from 532 customers of a Dutch online store. Our results showed significant effects of merchandise attractiveness, enjoyment, and online store communication style, mediated by consumers’ emotions. The study should enhance our understanding of online impulse buying and, by assessing the impact of the online store, of beliefs in non-rational decision-making settings.