A model of the interaction between mood and memory

This paper investigates a neural network model of the interaction between mood and memory. The model has two attractor networks that represent the inferior temporal cortex (IT), which stores representations of visual stimuli, and the amygdala, the activity of which reflects the mood state. The two attractor networks are coupled by forward and backward projections. The model is however generic, and is relevant to understanding the interaction between different pairs of modules in the brain, particularly, as is the case with moods and memories, when there are fewer states represented in one module than in the other. During learning, a large number of patterns are presented to the IT, each paired with one of two mood states represented in the amygdala. The recurrent connections within each module, the forward connections from the memory module to the amygdala, and the backward connections from the amygdala to the memory module, are associatively modified. It is shown how the mood state in the amygdala can influence which memory patterns are recalled in the memory module. Further, it is shown that if there is an existing mood state in the amygdala, it can be difficult to change it even when a retrieval cue is presented to the memory module that is associated with a different mood state. It is also shown that the backprojections from the amygdala to the memory module must be relatively weak if memory retrieval in the memory module is not to be disrupted. The results are relevant to understanding the interaction between structures important in mood and emotion (such as the amygdala and orbitofrontal cortex) and other brain areas involved in storing objects and faces (such as the inferior temporal visual cortex) and memories (such as the hippocampus).     

规则网络中的SIRS病毒局域控制建模与仿真*

提出一个带有局域控制的二维规则网络SIRS模型,理论分析和计算机仿真都表明局域控制能很好地抑制此模型中的病毒传播。研究发现系统状态随时间的演化最终会达到一个稳定状态;病毒的稳态感染比例与传播效率、被控制个体比例和免役个体失去免役能力的概率有关。只有当传播效率大于一个临界值时,病毒才能在网络中持续传播。     

Analysis of the effects of quantization in multilayer neuralnetworks using a statistical model

A statistical quantization model is used to analyze the effects of quantization when digital techniques are used to implement a real-valued feedforward multilayer neural network. In this process, a parameter called the effective nonlinearity coefficient, which is important in the studying of quantization effects, is introduced. General statistical formulations of the performance degradation of the neural network caused by quantization are developed as functions of the quantization parameters. The formulations predict that the network's performance degradation gets worse when the number of bits is decreased; that a change of the number of hidden units in a layer has no effect on the degradation; that for a constant effective nonlinearity coefficient and number of bits, an increase in the number of layers leads to worse performance degradation; and the number of bits in successive layers can be reduced if the neurons of the lower layer are nonlinear     

A computational model of the interaction between environmental dynamics and economic behavior

Environmental issues have been considered to be very important for a long time. We believe that they should be examined from an interdisciplinary view point in order to reach a solution, because they have arises as the consequence of complex interactions among various factors. This article proposes a new model termedColorChanger. By using this model, we aim to explore the nature of ecological issues beyond separate discussions on specific subjects, and make the acquired knowledge available to encourage the solution of environmental issues. This article also reports on the results of the preliminary experiments. This work was presented in part at the Sixth International Symposium on Artificial Life and Robotics, Tokyo, January 15–17, 2001     

Fluid-structure interaction: A general method used in the ceasemt computer programs

This paper presents a general method to calculate the dynamic behaviour of coupled fluid-structure systems. It is shown how this method can be easily implemented in finite element computer codes. Some applications in the case of axisymetric and three dimensional structures are compared either with analytical or with experimental results. A reference is given for fluid-structure interaction in piping systems.     

User documentation and control language I: Evaluation and comparison of statistical computer packages

Procedures for comparing and evaluating aspects of the user interface of statistical computer packages are described. These procedures are implemented in a study of three packages. SPSS. BMDP and Minitab, by a class of 21 students with some statistical background. It was found that most participants exhibited consistent personal preferences among the packages. In selecting packages to solve specific problems, however, their choice was determined more by issues of good statistical practice than by personal preference for overall package features.     

Theoretical study of chlordecone and surface groups interaction in an activated carbon model under acidic and neutral conditions

Activated carbons (ACs) are widely used in the purification of drinking water without almost any knowledge about the adsorption mechanisms of the persistent organic pollutants. Chlordecone (CLD, Kepone) is an organochlorinated synthetic compound that has been used mainly as agricultural insecticide. CLD has been identified and listed as a persistent organic pollutant by the Stockholm Convention. The selection of the best suited AC for this type of contaminants is mainly an empirical and costly process. A theoretical study of the influence of AC surface groups (SGs) on CLD adsorption is done in order to help understanding the process. This may provide a first selection criteria for the preparation of AC with suitable surface properties. A model of AC consisting of a seven membered ring graphene sheet (coronene) with a functional group on the edge was used to evaluate the influence of the SGs over the adsorption. Multiple Minima Hypersurface methodology (MMH) coupled with PM7 semiempirical Hamiltonian was employed in order to study the interactions of the chlordecone with SGs (hydroxyl and carboxyl) at acidic and neutral pH and different hydration conditions. Selected structures were re-optimized using CAM-B3LYP to achieve a well-defined electron density to characterize the interactions by the Quantum Theory of Atoms in Molecules approach. The deprotonated form of surface carboxyl and hydroxyl groups of AC models show the strongest interactions, suggesting a chemical adsorption. An increase in carboxylic SGs content is proposed to enhance CLD adsorption onto AC at neutral pH conditions.     

A team-teaching model for practicing project-based learning in high school: Collaboration between computer and subject teachers

Project-based learning (PBL) is a highly effective means of motivating students to learn independently. However, training or encouraging teachers to practice PBL in their classrooms is challenging, especially if the educational system does not accommodate creative teaching practices. In particular, in a test-driven educational system, time constraints and an excess of teaching content makes it difficult to practice PBL at the high school level. This work presents a novel team-teaching model that is based on collaboration between subject teachers and the computer teacher to facilitate PBL in the classroom. A two-year experiment was conducted to study the feasibility of the proposed model, in which the school computer teacher conducts PBL with the 10th grade students in the first year, and subject teachers conduct PBL with the 11th grade students in the second year. Experimental results indicate that the proposed model is feasible in the given educational setting. No class time was lost, and the subject teacher successfully conducted PBL activities. Furthermore, a follow-up survey indicated that the students enjoyed the PBL activities in both classes.     

Non-extensive statistical analysis of seismicity in the area of Javakheti, Georgia

The distribution of earthquake magnitudes in the Javakheti highlands was analyzed using a non-extensive statistical approach. The earthquakes occurring from 1960 to 2008 in this seismically active area of Southern Caucasus were investigated. The seismic catalog was studied using different threshold magnitude values. Analyses of the whole time period of observations as well as of sub-catalogs of consecutive 10-year span time windows were performed. In every case non-extensive parameter q and value a, the physical quantity characterizing energy density, were calculated from the modified frequency–magnitude relationship. According to our analysis the magnitude sequence in the Javakheti area for the whole period of observation is characterized by a non-extensivity parameter q=1.81, in the upper limit of values reported elsewhere. While calculated non-extensivity parameters for consecutive 10-year windows fall within the range 1.6–1.7 reported worldwide. A significant increase of parameter q was identified in those 10-year sub-catalogs that included the strongest earthquakes within the period of observation. We suppose that this increase may be related to a more correlated behavior within the system of ‘fault fragments’ when a strong earthquake strikes or immediately after; during aftershock activity. Concurrently, smaller values of non-extensivity parameters q_i, found during seismically relatively quiet times, could be associated to the decreased correlations within the system during the earthquake generation stage, under an essentially decreased tectonic stress. The behavior of the energy density characteristic a almost mirrors the variation of parameter q: increases for seismically quiet periods in the Javakheti area and decreases in periods when strong earthquakes occur. We suggest that decreases of energy density characteristic a may point to a prevalent contribution of large size fragments to fragment–asperity interaction under the influence of a rapidly released stress, as opposed to relatively quiet periods when accumulated stress energy is supposedly released through the relative movement of smaller fragments.     

Interfacing human and computer with wireless body area sensor networks: the WiMoCA solution

Wireless Body Area Sensor Networks (WBASN) are an emerging technology enabling the design of natural human–computer interfaces (HCI). Automatic recognition of human motion, gestures, and activities is studied in several contexts. For example, mobile computing technology is being considered as a replacement of traditional input systems. Moreover, body posture and activity monitoring can be used for entertainment and health-care applications. However, until now, little work has been done to develop flexible and efficient WBASN solutions suitable for a wide range of applications. Their requirements pose new challenges for sensor network designs, such as optimizing traditional solutions for use as environmental monitoring-like applications and developing on-the-field stress tests. In this paper, we demonstrate the flexibility of a custom-designed WBASN called WiMoCA with respect to a wide range of posture and activity recognition applications by means of practical implementation and on-the-field testing. Nodes of the network mounted on different parts of the human body exploit tri-axial accelerometers to detect its movements. The advanced digital Micro-electro-mechanical system (MEMS) based inertial sensor has been chosen for WiMoCA because it demonstrated high flexibility of use in many different situations, providing the chance to exploit both static and dynamic acceleration components for different purposes. Furthermore, the sensibility and accuracy of the sensing element is perfectly adequate for monitoring human movement, while keeping cost low and size compact, thus meeting our requirements. We implemented three types of applications, stressing the WBASN in many aspects. In fact, they are characterized by different requirements in terms of accuracy, timeliness, and computation distributed on sensing nodes. For each application, we describe its implementation, and we discuss results about performance and power consumption.

Qualitative differences in computer experience, computer anxiety, and students' use of computers: A path model

Biographical information (age and gender) was obtained on 180 first year psychology students along with self-report measures relating to computer use. The measures were: age of initial introduction to computers; qualitative aspects of early computer experience (how relaxed and unpressured the experience was and the extent to which the individual had felt ‘in control’ and competent during the experience); level of computer anxiety; current and anticipated future frequency of use of computers. A path model linking the above variables was proposed and tested. Apart from gender, all of the predictor variables exerted direct and/or indirect influences on use made (and expected to be made) of computers. In particular, an early introduction to computers was generally associated with a more favourable quality of initial experience, leading to lower anxiety and greater readiness of students to use computers.     

Three-dimensional computer model of the heart: fibrillation induced by extrastimulation

We present a three-dimensional (3D) computer model that simulates electrical activity in the heart during fibrillation. A real dog heart is discretized to form 1473 interconnected cubic elements. The model exhibits normal activation and recovery from pacing. Five or more extrastimuli induce a self-sustaining tachyarrhythmia that soon degenerates into a fibrillatory rhythm. The extrastimuli increase the excitability of the myocardial cell population. The result is a rapid re-excitation of cells that allows for only a partial recovery of cell action potential. This suggests that a dispersion of refractory states of the cell population is the cause of fibrillation in this computer model.     

Mathematical and statistical details on the simulation of MARKOFF-Type stochastic processes on an electronic computer

Summary This paper deals with the generation of stationaryp ^th order linear autoregressive series (calledM _p -series) on an electronic computer. The interrelations between the coefficients of autocorrelation are discussed and a device and a flow diagram are given for the generation ofM _p -series which possess the autocorrelation coefficients ₁, ₂,... _p . The conclusion is that there is anM _p -series for a given set of values only if there is anM _q -series for any subset ₁,... _q withq=1,2,...q–1 and that, conversely, if there is anM _p -series for given ₁,₂,... _p , there is also anM _q -series with ₁,... _q for 1q<p.The series withp=1, 2, 3 are treated fully and numerical examples forp=1 andp=2 are given in Fig. 4.

---

Zusammenfassung In diesem Aufsatz wird besprochen wie mit Hilfe einer elektronischen Rechenmaschine stationäre lineare autoregressive Reihen der Ordnungp (M _p -Reihen genannt) konstruiert werden können. Nachdem die Beziehungen zwischen den Autokorrelationskoeffizienten abgeleitet worden sind, wird ein Schema und ein Flußdiagramm zur Erzeugung vonM _p -Reihen gegeben, die vorgegebene Autokorrelationskoeffizienten ₁,... _p besitzen. Das Ergebnis lautet: EineM _p -Reihe für eine Gruppe von gegebenen Werten ₁,... _p ist nur möglich, wenn eineM _q -Reihe für jede Untergruppe ₁,... _q mitq=1, 2, ...p–1 möglich ist. Wenn einmal eineM _p -Reihe mit gegebenen ₁,... _p existiert, dann existiert ebenfalls jedeM _q -Reihe mit ₁,... _q , wobei 1q<p ist.Die Fällep=1, 2, 3 werden ausführlich behandelt, während die Abb. 4 numerische Beispiele fürp=1 undp=2 zeigt.

---

---

With 4 Figures     

Analytical model of interaction between contention-based and deterministic channel access mechanisms in Wi-Fi Mesh networks

A new analytical model was developed to estimate the degree of mutual influence of the links between the stations of Wi-Fi Mesh networks which use different channel access methods specified by the IEEE 802.11s standard, namely, contention-based channel access mechanism and the deterministic channel access mechanism based on the preliminary reservation of channel resources. The model was used to compare the efficiency of different backoff counting methods proposed in the paper for providing the interaction between two channel access methods. Additionally, the model was also used to analyze the effect of different techniques for arranging the time intervals reserved by means of the deterministic channel access mechanism on the performance of stations using contention-based channel access mechanism.     

The kernel density estimate/point distribution model (KDE-PDM) for statistical shape modeling of automotive stampings and assemblies

The ability to effectively model dimensional variation of stampings and assemblies is an important tool for manufacturers to investigate, assess and control quality levels of their products. Statistical Process Control (SPC) and Six-Sigma approaches use the assumptions of statistical independence and normally distributed data to create quality process control guidelines which are predominantly used in industry. Multivariate statistical techniques such as Principal Components Analysis (PCA) have been more recently applied to automotive body assembly analysis in order to capture the surface co-linearity present in the dimensional variation of stampings and assemblies. This paper combines the Point Distribution Model, which is based on PCA, and Kernel Density Estimation to provide a statistical shape model (the KDE–PDM) that can deal with high dimensional data sets, represent correlated variation modes, and provide accurate estimates of the underlying shape distribution. Examples from FE simulation and production case studies are presented to highlight the advantages of the KDE–PDM over two other statistical shape models: the univariate shape model, and the original PDM. The KDE–PDM's capabilities make it particularly suited to variation monitoring and diagnosis of high dimensional measurement data sets made available by optical measurement devices, and some suggestions for its implementation are also presented.     

Understanding pre-service teachers' computer attitudes: applying and extending the technology acceptance model

Abstract   Computers are increasingly widespread, influencing many aspects of our social and work lives, As we move into a technology-based society, it is important that classroom experiences with computers are made available for all students. The purpose of this study is to examine pre-service teachers' attitudes towards computers. This study extends the technology acceptance model (TAM) framework, with subjective norm and facilitating conditions acting as external variables. Results shows that perceived usefulness, perceived ease of use and subjective norm were significant determinants of pre-service computer attitudes. Facilitating conditions did not influence computer attitude directly but through perceived ease of use. These findings demonstrate that social norm and facilitating conditions are potential variables that may be used to extend the TAM for research on computer attitudes.     

改进的SIR计算机病毒传播模型

通过分析已有网络病毒模型的不足,结合现实情况,根据生物学中的传染病模型提出了一种改进的具有预先免疫措施的SIR计算机病毒传播模型,该模型充分考虑了网络中节点数量变化对病毒传播的影响。此外,利用微分方程理论分析了模型的动力学行为。数值模拟结果表明,提高预先免疫率和控制节点流动可以有效控制病毒在网络中的传播。     

可可西里湖泊水面面积与雪冰覆盖率相关分析

气候变化对青藏高原湖泊水面面积会产生很大的影响,雪冰覆盖作为气候变化的一个重要因素,也对青藏高原湖泊水面面积有一定的影响。利用遥感影像提取2009—2017年可可西里地区库塞湖及周边四湖(简称为四湖)的年水面面积,同时,利用2005—2016年的MODIS积雪产品,提取四湖集水区雪冰覆盖率,结合同期五道梁气象站点的逐月平均气温数据和降水量,对四湖水面面积变化与集水区雪冰覆盖变化规律及其与五道梁站气温与降水量之间的关系进行探讨。分析表明:1)卓乃湖2011年9月溃决后,4个湖泊的水面面积都发生较大的改变;2)2005—2014年期间,四湖集水区雪冰覆盖率总体呈小幅度增加趋势;3)卓乃湖溃决后,库塞湖及卓乃湖的水面面积与五道梁站年均气温的相关性显著提高,而库塞湖及卓乃湖的水面面积与四湖集水区雪冰覆盖率的相关性显著降低。