视觉交互系统中的目标检测与运动分析

论文以视觉交互系统的一个原型———VIP-3D(VisualInteractionPlatformof3D)系统为例,阐述了该系统设计中所解决的若干关键问题:目标的检测、匹配和投影运动分析,尤其对目标检测过程中需要注意的问题和具体算法、二维到三维坐标的映射、实体运动分析算法的推导等作了详尽的介绍,并从人机交互方面给出了实验性能分析。     

具有多出入口区域的节点移动和分布研究

在Ad Hoc网络的仿真研究中,节点移动模型的选择会严重影响到网络的拓扑结构和通信协议的性能.然而,现有移动模型大多是为理想环境设计的,不能适用于真实环境.在理想移动模型RWP(Random Waypoint)的基础上,提出了具有多出入口区域的RWP节点移动模型(RWP with entrances,RWPWE).在该模型中,区域出入口是节点进出区域的必经之地,节点在区域内的移动符合RWP节点移动模型,通过引入域内停留概率来完成节点在区域内外移动的转移,并从节点移动速度、移动时间、移动路程和空间分布概率等几个方面研究了区域出入口的影响.理论分析和实验仿真的结果表明,由于出入口的存在,与RWP模型相比节点的移动更加复杂,节点的空间分布也显著不同,这些差别将会影响到网络的拓扑性能和对网络协议的评价.     

Investigating Smartphone Touch Area with One-Handed Interaction: Effects of Target Distance and Direction on Touch Behaviors

ABSTRACT

The objective of this study was to investigate the touch area that can be comfortably reached by the thumb during one-handed smartphone interaction. To achieve the research objective, we introduced the concept of natural thumb position when designing a tapping task and conducted an user experiment. The independent variables were the target distance and direction from the natural thumb position, and the three dependent variables were the task performance, information throughput, and touch accuracy. The results showed that participants performed the task comfortably in the diagonal direction between the upper right and the lower left side of the screen. The task performance deteriorated as the target distance increased, especially at 45 mm or more. The touch accuracy was measured using X- and Y-coordinates data. Participants touched the left side of the target center, except near the proximal area of the hand. They also touched the points above the center of the target in the upper screen area and points below the center of the target in the lower screen area. The findings of this study provided insights for designing a smartphone touch interface considering the comfortable touch areas of one-handed interaction.     

Computing Equilibrium Wealth Distributions in Models with Heterogeneous-Agents, Incomplete Markets and Idiosyncratic Risk

This paper describes an accurate, fast and robust fixed point method for computing the stationary wealth distributions in macroeconomic models with a continuum of infinitely-lived households who face idiosyncratic shocks with aggregate certainty. The household wealth evolution is modeled as a mixture Markov process and the stationary wealth distributions are obtained using eigen structures of transition matrices by enforcing the conditions for the Perron–Frobenius theorem by adding a perturbation constant to the Markov transition matrix. This step is utilized repeatedly within a binary search algorithm to find the equilibrium state of the system. The algorithm suggests an efficient and reliable framework for studying dynamic stochastic general equilibrium models with heterogeneous agents.     

三本院校软件工程实践教学的研究与实践

结合国家对软件人才的需求,针对软件工程专业实践教学现状,分析了三本院校软件工程实践教学的问题,针对应用型人才培养的目标,该文从课程教学计划的制订、实例教学、实验教学、社会实践教学几个环节进行了研究,提出了相关的实践教学理论及改革措施。     

Nash-Cournot Equilibria in Power Markets on a Linearized DC Network with Arbitrage: Formulations and Properties

Extending a prior arbitrage-free model of Hobbs (2001), this article presents two models of an electric power market with arbitrage on a linearized DC network with a affine price functions. The two models represent a decentralized system involving bilateral contracts between producers and consumers in which the system operator's role is limited to providing transmission services. The two models differ in how arbitrage is handled. In the first model, the producers anticipate the effect of arbitrage upon prices at different locations (Stackelberg assumption), and therefore treat the arbitrage amounts as decision variables in their profit maximization problems. In the second model, the firms take the arbitrage quantities as inputs in their problems (Cournot assumption), and the arbitrager solves a separate profit maximization problem that takes the electricity prices and the transmission costs as inputs. In each model, we adopt a Nash-Cournot equilibrium as the solution concept for the game among producers. We show that the resulting equilibrium problems can be formulated as monotone mixed linear complementarity problems. Based on such a formulation, we obtain existence,uniqueness,and various quantitative properties of the equilibrium solutions to the models. It is also demonstrated that these two models of a bilateral market yield the same prices, producer outputs, and profits as a model of Cournot competition in a Poolco system,in which a system operator runs a centralized auction and buys all production, and then resells it to consumers. This result implies that Cournot competition among producers yields the same outcomes for two distinct market designs. Finally, we present a numerical example to illustrate the theoretical results.     

Interacting Socially with the Internet of Things (IoT): Effects of Source Attribution and Specialization in Human–IoT Interaction

This study investigates the theoretical mechanisms by which the variations in source attribution (multiple sources vs. single source) and specialization (multifunctionality vs. single functionality) of Internet of Things (IoT) devices influence the quality of human–IoT interaction. Results from a between‐subjects experiment (N = 100) indicate that IoT devices that elicit the sense of multiple agencies and are specialized in a single function induce greater social presence and perceived expertise, which, in turn, lead individuals to show a more positive attitude toward the devices and to ascribe greater quality to the information transmitted by them. The results also reveal that the effect of multiple source attribution is more pronounced for individuals for whom the content of the information has low personal relevance.     

数学专业课程教学现状及多媒体CAI策略构想

分析了目前数学专业课程的教学现状 ,阐明了数学专业课程CAI教学的特点 ,并提出了实现多媒体CAI策略的一些构想     

符合GMP要求的中药制剂智能生产线管控系统设计

本论文介绍了符合GMP认证的中药制剂智能生产线管控系统,综合应用自动控制、数据库、智能优化等先进技术与方法,对生产过程涉及的主要工艺参数如压力、流量、浓度、温度、电导率、重量等进行在线测控与优化,保证生产过程稳定和精准控制.建立完整可靠的生产过程实时数据库和关系数据库,解决中药制药生产信息化和集成化等生产问题,同时满足企业GMP认证要求.     

Effects of positioning optimization in an alternative computer workstation for people with and without low back pain

The aim of this study was to measure the impact of positioning optimization on typing performance and user comfort for people with and without low back pain (LBP) in alternative working postures. Participants completed a series of typing tests in each of five randomly ordered alternative working postures ranging from upright to fully supine. Typing accuracy and typing speed were recorded as were subjective measures of overall comfort and body part discomfort. The impact of positioning optimization of the monitor, keyboard, and arm supports was determined by comparing results from an “Optimized” test study protocol (n = 27) with those from a “Non-Optimized” test study protocol (n = 26). The results indicate a significant improvement in user comfort with the optimized positioning, but no significant differences in typing performance between the two test protocols. However, in both tests the slowest typing speeds occurred in the fully reclined and zero gravity working postures. Results of the user comfort scores indicated that for the Non-Optimized test, all alternative working postures were less comfortable than the upright posture. Whereas, in the Optimized test the tilted and reclined postures were comparable to the upright working posture and only the zero gravity posture was viewed as less comfortable.

Relevance to industry

Understanding the importance of position optimization for VDT operators in alternative working postures will provide valuable information toward the development of more comfortable and more accommodating computer workstations.     

Effects of delay on the type and velocity of travelling pulses in neuronal networks with spatially decaying connectivity

We study a one-dimensional model of integrate-and-fire neurons that are allowed to fire only one spike, and are coupled by excitatory synapses with delay. At small delay values, this model describes a disinhibited cortical slice. At large delay values, the model is a reduction of a model of thalamic networks composed of excitatory and inhibitory neurons, in which the excitatory neurons show the post-inhibitory rebound mechanism. The velocity and stability of propagating continuous pulses are calculated analytically. Two pulses with different velocities exist if the synaptic coupling is larger than a minimal value; the pulse with the lower velocity is always unstable. Above a certain critical value of the constant delay, continuous pulses lose stability via a Hopf bifurcation, and lurching pulses emerge. The parameter regime for which lurching occurs is strongly affected by the synaptic footprint (connectivity) shape. A bistable regime, in which both continuous and lurching pulses can propagate. may occur with square or Gaussian footprint shapes but not with an exponential footprint shape. A perturbation calculation is used in order to calculate the spatial lurching period and the velocity of lurching pulses at large delay values. For strong synaptic coupling, the velocity of the lurching pulse is governed by the tail of the synaptic footprint shape. Moreover, the velocities of continuous and lurching pulses have the same functional dependencies on the strength of the synaptic coupling strength gsyn: they increase logarithmically with gsyn for an exponential footprint shape, they scale like (In gsyn)1/2 for a Gaussian footprint shape, and they are bounded for a square footprint shape or any shape with a finite support. We find analytically how the axonal propagation velocity reduces the velocity of continuous pulses; it does not affect the critical delay. We conclude that the differences in velocity and shape between the front of thalamic spindle waves in vitro and cortical paroxysmal discharges stem from their different effective delays.     

Interaction of Ia and IIa group cations with the guanine site in cytosine-guanine nucleic acid base pair: an ab initio Hartree Fock study in the absence of basis set superposition error

Structures and energetics of complexes between guanine...cytosine Watson Crick (GCWC) DNA base pair and various metal cations were investigated by an ab initio Hartree Fock (HF) study in the absence of basis set superposition error. Cations were allowed to interact with N7 and O6 sites of guanine. The BSSE free gradient geometry optimisation were performed in the framework of the SCF-MI (self consistent field for molecular interactions) theory. In particular, the structure of the complex with the mono and bivalent cations, like H+, Na+, K+, Mg++, Ca++ were analysed showing that the coordination to the N7 and O6 sites of the GCWC pair can generate non-WC hydrogen bonding patterns. The results demonstrate that the a priori elimination of the BSSE allows to study molecular clusters of biological interest by employing small basis sets.     

Effects of the resting time associated with the number of trials on the total and individual finger forces in a maximum grasping task

The repetitive and excessive workload accompanying grip strength- or hand-intensive tasks are often considered to be common causes of work-related upper limb musculoskeletal disorders. For this reason, numerous experimental studies have been performed on maximum grip strength. However, due to an absence of standard guidelines, researchers have adopted different resting times and number of trials suited for their particular research purposes. The effects of resting time and the number of trials on the maximum total grip strength and individual finger forces of 24 participants over 20 trials were investigated. Results showed that the total grip strength and individual finger strengths differed significantly according to the resting time and the number of trials (p < 0.05). Overall, grip strength tended to increase with a reduction in resting time (% reduction: 7.8%, 9.1%, 11.1%, and 13.0% for 3 min, 2 min, 1 min, and 30 s resting time, respectively) as well as with an increase in the number of trials (% reduction: 8%, 10%, 13%, and 16% for 5th, 10th, 15th, and 20th trials). The effects of resting time and the number of trials also showed statistically significant effects on individual finger forces. Regression equations of total grip strength and finger forces with resting time and number of trials were established. These equations were then applied to formulate guidelines for appropriate resting times in experiments based on the number of trials and acceptable reductions in grip strength. Data from this and future studies regarding decreasing grip strength and the contribution of each finger are expected to form the groundwork for ergonomic hand tool design and development.     

Income, Time Effects and Direct Preferences in a Multimodal Choice Context: Application of Mixed RP/SP Models with Non-Linear Utilities

Transport problems typically involve at least two types of constraints, on income and on time. Therefore, the indirect utility function depends either on the income available after having subtracted the cost of the discrete alternative and on the free time left after having worked and travelled by each competing option. In the typical linear-in-the-attributes and in-the-parameters specification, that represents the first grade approximation of the indirect utility function, the effect of income and time constraints cancel out and only the cost and time of the alternatives matter in the comparison between them. From a microeconomic point of view this is equivalent to assume that income and time effects could be disregarded; which is not always the case. To account for these effects the utility function should include second order attributes; however, in non-linear utility functions it may not be easy to distinguish among several effects that could be relevant: direct preferences for good and leisure, and simple interactions between attributes other than income and time effects. This paper analyses these effects from a theoretical point of view focusing on the possible confounding problem in detecting income and time effects. We use a dataset collected for a modal choice context and containing both revealed and stated preference data, and estimate several NL models examining the effect of the different second-order terms on detecting income and time effects. We compared specifications including square cost and time attributes, interactions between time and cost, cost divided by the income available to be spent on free time, and time multiplied by free time. Our results confirm the strong effect of direct preferences for goods and leisure time on choice, and the potential confounding effect between quadratic attributes and other non-linear omitted terms. Finally, we also found that care should be taken in highlighting income and time effects using mixed data sources, since confounding effects can occur when non-linearities are accounted for in both data sets.