How Presence Affects College Students’Online Learning Outcomes:Unveiling Its Underlying Mechanism

Over the past few years,China’s higher education institutions have experienced remarkable growth in online teaching.However,it remains uncertain whether and how the sense of presence perceived by students affects their online learning outcomes when teachers use online teaching media for communication.This sense specifically pertains to the extent to which students perceive themselves as“real persons”and establish connections with others.Therefore,this study constructs a conceptual model elucidating the impact of presence on students’online learning outcomes and empirically examines the mechanism through which three types of presence influence students’online learning.The test results of the structural equation modeling(SEM)indicate that:(a)teaching presence,social presence,and cognitive presence all exhibit significantly positive outcomes on students’online learning outcomes;(b)these three types of presence can also indirectly and positively influence students’online learning outcomes through the mediating effect of flow experience and learning satisfaction;and(c)flow experience and learning satisfaction play a sequential mediating role in the process by which presence impacts students’online learning outcomes.We hope that the relevant research findings may contribute to unveiling the“black box”of the impact of presence on students’online learning outcomes and offer valuable insights for college educators to overcome online teaching constraints and enhance online teaching quality.

Spatial Multi-Presence System to Increase Security Awareness for Remote Collaboration in an Extended Reality Environment

Enhancing the sense of presence of participants is an important issue in terms of security awareness for remote collaboration in extended reality.However,conventional methods are insufficient to be aware of remote situations and to search for and control remote workspaces.This study pro-poses a spatial multi-presence system that simultaneously provides multiple spaces while rapidly exploring these spaces as users perform collaborative work in an extended reality environment.The proposed system provides methods for arranging and manipulating remote and personal spaces by creating an annular screen that is invisible to the user.The user can freely arrange remote participants and their workspaces on the annular screen.Because users can simultaneously view various spaces arranged on the annular screen,they can perform collaborative work while simultaneously feeling the presence of multiple spaces and can be fully immersed in a specific space.In addition,the personal spaces where users work can also be arranged through the annular screen.According to the results of the performance evaluations,users participating in remote collaborative works can visualize the spaces of multiple users simultaneously and feel their presence,thereby increasing their understanding of the spaces.Moreover,the proposed system reduces the time to perform tasks and gain awareness of the emergency in remote workspaces.

Beyond Video Quality:Evaluation of Spatial Presence in 360-Degree Videos

With the rapid development of immersive multimedia technologies,360-degree video services have quickly gained popularity and how to ensure sufficient spatial presence of end users when viewing 360-degree videos becomes a new challenge.In this regard,accurately acquiring users’sense of spatial presence is of fundamental importance for video service providers to improve their service quality.Unfortunately,there is no efficient evaluation model so far for measuring the sense of spatial presence for 360-degree videos.In this paper,we first design an assessment framework to clarify the influencing factors of spatial presence.Related parameters of 360-degree videos and headmounted display devices are both considered in this framework.Well-designed subjective experiments are then conducted to investigate the impact of various influencing factors on the sense of presence.Based on the subjective ratings,we propose a spatial presence assessment model that can be easily deployed in 360-degree video applications.To the best of our knowledge,this is the first attempt in literature to establish a quantitative spatial presence assessment model by using technical parameters that are easily extracted.Experimental results demonstrate that the proposed model can reliably predict the sense of spatial presence.

The Contribution Margin due to a Limiting Factor in the Presence of Several Sales Options: Actuality Is Not Always As It Appears at the Beginning of the Analysis

The analysis of company data useful for economic decisions,if not interpreted in an overall view of the company situation,can lead to wrong conclusions.This is the case when a company has to choose between several sales options for one or more products in the presence of a limiting factor.The continuation of the investigation often denies the initial analysis.Not everything is as it appears,therefore,at the beginning of the deepening of the data useful for economic decisions.As it is well known,the choices of profitability concerning the planning of the sale of company products take place,at least in the majority of cases,through the determination of the contribution margin,i.e.the profitability margin connected to the individual goods/services sold by the companies(selling price net of variable costs).The contribution margin can be determined with four objectives:(1)Determination of the yield of the single product,net of variable costs only.In this case,the margin defines unitary,from net product yield to unitary contribution margin.(2)Determination of the return on total sales of an individual product,net of variable costs.In this hypothesis,reference is made to the first level(or gross)contribution margin.(3)Determination of the ability of the individual product to contribute to the coverage of fixed costs common to the company.This margin is determined net of special product variable and fixed costs.This aggregate is defined as a Level II(or semi-gross)margin.(4)Determination of the useful value in the planning choices in case of presence of scarce productive factors.In this case,it must identify the so-called unitary margin for low factor.Here we will only deal with the problem of the use of the contribution margin in the presence of rare factors.To complete the analysis,below are some very brief considerations regarding,respectively,the unitary,level I,and level II contribution margin in order to better understand where the problem of the most convenient choice of income is located in the event of the presence of rare production factors,especially in an environment characterized by a plurality of sales options.

3G网络中的Presence业务

在介绍Presence业务总体特征的基础上,通过业务场景说明业务的具体应用,简单阐述了Presence业务的网络结构,最后介绍了目前国内外研究情况以及展望Presence业务发展前景。

一种新的Presence建模方法

在分析Presence信息特征的基础上，提出了Presence模型的建模需求和功能目标，并指出：信息共享、隐私保护以及信息融合要求对信息提供一致的管理方式，可通过建立Presence信息模型来解决这一问题，信息模型的建立应该直观和易用。根据建模需求对适用的建模方法进行了比较，建立了一种新的面向普通应用开发者的混合建模方法，结合图形化建模和本体建模的优点，在建模过程引入了模型驱动结构（MDA）方法和工程化思想，标准化的表达方式和规范的建模步骤保证了建模的质量。

基于SIP协议的Presence服务的研究

Presence服务是多媒体会议、即时消息等网络应用中的一项重要服务。SIP协议可以很好的作为一种Presence协议来实现presence服务,本文通过SIP协议的SUBSCRIBE、NOTIFY和扩展的PUBLISH方法,使用SIP协议的事件通知机制设计了一个基于SIP协议的Presence服务系统。

Presence服务中授权机制的研究

随着IP通信业务的发展,Presence业务在通信系统中起着越来越重要的作用。用户发布的Presence信息包含越来越多的私人信息和敏感信息,Presence服务器需要经过发布者授权后才能把Presence信息发布给观察者。针对授权规则问题IETF提出了两种解决方法:Watcher Info机制和XCAP机制。本文主要介绍基于SIMPLE的Presence服务系统中两种机制的实现方法,对比分析两种机制的优缺点,在此基础上分析两者的发展前景。

基于P2P-SIP的Presence业务

即时通信作为一种通信形式受大众喜爱。本文简单说明了当前即时消息软件的不足,通过分析标准SIP协议的技术优势和P2P网络的良好特性。提出了较为稳定、安全、易于扩充的Presence业务模型。

Load Static Models for Conservation Voltage Reduction in the Presence of Harmonics

The Conservation Voltage Reduction (CVR) is a technique that aims to achieve the decrease of power consumption as a result of voltage reduction. The customer is supplied with the lowest possible voltage level compatible with the stipulated level by the regulatory agency. International Standards ANSI C84.1-2006 and IEEE std 1250-1995 specify the range of supply voltage to electronics equipment from 0.9 to 1.05 pu of nominal voltage. To analyse the CVR effect in distribution systems with different load characteristics (residential, commercial, industrial or a combination of these), mathematical load models are used. Typically, these equipment/load models are used to analyse load aggregation without any consideration of its nonlinearity characteristics. Aiming to analyse the nonlinear characteristics and its consequences, this paper presents a discussion of the neglected variables as well as the results of a set of measurements of nonlinear loads. Different mathematical models are applied to obtain them for each load. Using these models the load aggregation is evaluated. It is presented that although the models show adequate results for individual loads, the same does not occur for aggregated models if the harmonic contribution is not considered. Consequently, to apply the load model in CVR it is necessary to consider the harmonics presence and the model has to be done using only the fundamental frequency data. The discussion about the causes is done and the models are compared with the measurements.

Robotic Electrotactile Feedback Glove for Tele Presence System

Progress is described regarding the development of a new electrotactile feedback glove designed for application to dexterous robot. The sensitivity of operator's finger against electrical stimulus pulse is considered. It is found that frequency, duty ratio, and voltage amplitude of electrical stimulus pulse determine the sensitivity of finger. The effects of materials, sizes, arrangements and shapes of electrodes on sensitivity of finger are analyzed. Finally, the tactile tele presence system is designed to experimentally confirm that the robot with electrotactile feedback glove can manipulate dexterous robotic multi fingered hand and identify and classify three sorts of objects.

IMS中基于Presence生活导航系统的设计与实现

生活导航系统LPS(Life Presence System)是将Presence的机制扩展到呈现日常生活相关的事物状态变化的应用中,并提供交互式的操作完成用户行为的导航。文章描述了生活导航系统的主要应用场景以及应用的前景,介绍了IMS(IP Multimedia Subsystem)中基于Presence业务能力的生活导航系统的网络结构以及功能,提出了LPS系统的详细实现方案,并对系统实现的关键技术进行了分析。

Small-Scale Self-Focusing of Intense Laser Beams In the Presence of Vector Effect

We extend Bespalov-Talanov (B-T) theory on small-scale self-focusing (SSSF) to include vector effect of a very narrow intense laser beam with application of the vector self-focusing model. The gain spectrum for perturbations is obtained by using the standard linear instability analysis. It is shown that the influence on SSSF of vector effect is closely related to the beam width. For a very narrow beam, the role played by vector effect becomes significant, it reduces the fastest growing frequency and the maximum growth rate, and shortens the frequency range for perturbation growing, and thus deviates the gain spectrum from that of B-T theory.

Presence of Antibodies to Heat Stress Proteins and its Possible Significance in Workers Exposed to High Temperature and Carbon Monoxide

Antibodies to the ubiquitous group of stress proteins known as heat shock proteins (Hsps) have been found to be associated with a number of diseases in humans. Hsps are known to be induced by certain xenobiotics, some of which are common in the working environment. The biological significance of the presence of such autoantibodies is presently unclear. In the present study, we used immunoblotting to investigate the presence of antibodies against the different stress proteins, Hsp27, Hsp60, Hsp71, Hse (heat shock cognate ) 73 and Hsp89a and D in groups of workers exposed to high temperature or carbon monoxide. These data were related to a detailed clinical evaluation and to various laboratory measurements including electrocardiogram (ECG), B echogram, white blood cell counts and typing, the activity of alanine aminotransferase (ALT), acid phosphatase (ACP) and alkaline phosphatase (ALP) and lymphocyte DNA damage. Antibodies to Hsp27 and Hsp71 were found more frequently in the high temperature and carbon monoxide-exposed groups than in controls (P (0.05 ). The carbon monoxide-exposed group showed the highest incidence of anti-Hsp antibodies. Anti-Hsp60 antibodies were only detected in workers exposed to high temperature or carbon monoxide. The percentage of workers with abnormal ECG, B echogram changes and displaying hepatitis B antigen (HBsAg ) was higher in the carbon monoxide group than in the control group (P＜0.05 ).There was a significant inerease in the activity of ALT in the high temperature and carbon monoxide groups and in the activities of ACP and ALP in the carbon monoxide group (P＜0.05 ). The extent of DNA damage measured in lymphoeytes was higher in workers from the high temperature and carbon monoxide-cxposed groups. We suggest that the increased frequeney of antibodies to Hsps is the result of these damages, of the release of denatured Hsps and of a decrease in the phagocytic ability of macrophages in these workers. The data gathered in the present study show a statistical relation between the occurrence of antibodies against Hsps and the frequency of health problems in workers and suggest a potential role for the antibodies as useful biomarkers to assess whether workers are experieneing environmental stress

THE PROCESS OF THE EMULSIFIER-FREE POLYMERIZATION IN THE PRESENCE OF BARIUM SULFATE POWDER

The process of emulsifier-free copolymerization of the Styrene-Butyl Acrylate-K_sS_sO_s-water in the presence of Barium Sulfate(BS)powder was investigated under varied conditions within the range of BS powder quantity,initiator concentration and reaction temperature.Experimental results showed that the rate of polymerization is proportional to 0.3-power of the BS quantity and 1.3-power of the initiator concentration.There is a linear relationship of 2/3-power for the conversion and time.A process for the polymerization is propose to explain the experimental results.

Investigating Social Presence in Audio and Text Online Interaction for Language Learning

This study aimed at comparing the level of social presence generated in a voice-based chat room and a text-based forum when learners tried to build personal relationships and form an online community for learning on an online language course in China. A mixed-method approach was taken for the study, drawing on data from questionnaires to find out about student perception of social presence, and postings of text messages and audio messages in the communication of the student learning process to search for students’ projected social presence in terms of affective, interactive and cohesive features. Interviews were also conducted to supplement additional information with the hope of forming a complete picture of social presence in the reality of an online learning environment. The text-based forum and the voice-based chat room were found to have a different impact on student social presence. In terms of student perception, most of them were more likely to get to know peers in the text-based forum and thus developed a sense of community in their learning process of the online course. Yet they believed that the voice-based chat room had the advantage of helping them with course learning. In the actual interaction, the voice-based chat room was more interactive although the text-based forum was more affective and cohesive. But in terms of the affective category, the problem with the existing framework in literature was that there were no prosodic features included. Therefore, in future more research is needed to probe for the relationship between prosodic sound features and social presence, and the present theoretic framework must be extended. In interviews, students explained that in the voice-based chat room prosodic features led to higher peer awareness, which further reinforced this need.

PHOTO-CIDNP STUDIES OF PHTHALIMIDE DERIVATIVES IN THE PRESENCE OF TRIETHYLAMINE

The photoreactivity of some phthalimides was tested by CIDNP studies on the reactions with triethylamine.

富美实在巴西首次推出生物杀线虫剂Presence

富美实公司在巴西市场首次上市生物杀线虫剂Presence,该杀线虫剂为枯草芽孢杆菌（Bacillus subtilis）和地衣芽孢杆菌（Bacillus licheniformis）复配剂,主要用于棉花和大豆等作物。公司称,Presence为种子处理可分散粉剂,是巴西市场首个用于种子处理的生物杀线虫剂。在施用早期,2种有效成分之间的协同作用就能够有效促进根系健康生长,且具有良好的稳定性。富美实公司补充说,在2种有效成分复配的市售产品中,Presence有效成分浓度最高,

Self-Organization of Charged Particulates in the Presence of External Force

Evolution of spatial distribution of charged particulates under the action of an external force is investigated. It is found that starting from a homogeneous Maxwellian distribution of particulates, clusters can form and aggregate. The evolution process, as well as the asymptotic number and configuration of the clusters formed, depends strongly on the strength of the external force. The particulates in most of the final clusters are in the crystal state, as can also be deduced from the corresponding velocity and auto-correlation functions.

Healthcare staff as promoters of parental presence at anesthetic induction:Net Promoter Score survey

BACKGROUND Surgical intervention is usually a traumatic event that causes stress and anxiety in the pediatric patient and the family environment.To reduce the harmful effects of presurgical anxiety,parental presence during induction of anesthesia(PPIA)is one of the more notable interventions used in medical centers.However,data on this measure are difficult to evaluate and often face resistance from healthcare staff.AIM To analyze the perception of the healthcare workers after the implementation of a PPIA program.METHODS A survey was developed and sent by email to all the healthcare staff working in the children’s area of a tertiary hospital.It consisted of 14 items divided into positive aspects of PPIA and negative aspects of PPIA evaluated with the use of a Likert scale(1 to 5).The demographics of the respondents were included in the data collected.The answers to the questions were interpreted through the Net Promoter Score(NPS).The statistical analysis compared the differences in the responses to each question of the survey made by the different groups of health personnel included.RESULTS A total of 141 surveys were sent out,with a response rate of 69%.Of the total number of responses,68%were from women and 32%from men.The average age of the participants was 42.3±10.6 years.As for the positive questions about the PPIA,83%had an NPS>50,and only one had a score between 0 and 50,which means that the quality of the service was rated as excellent or good by 100%of the respondents.On the other hand,100%of the negative questions about the PPIA had a negative NPS.Responses to the question“PPIA increases patient safety”were significantly different(P=0.037),with a lower percentage of pediatric surgeons(70%)thinking that PPIA increased patient safety,compared with anesthesiologists(90%),nursing(92%),and other medical personnel(96%).CONCLUSION The personnel who participated in the PPIA program at our center were in favor of implementation.There were no validated arguments to support worker resistance to the development of the PPIA.