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.

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.

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.

一种基于P2P-SIP的无中心Presence业务方法

本文在介绍Presence业务模型的基础上,分析了当前Presence业务提供方法在健壮性和扩展性方面存在的问题,并结合P2P-SIP的网络结构体系,提出了一种无中心的Presence业务提供方法。该方法基于DHT的storage模型,实现了Presence信息的分布式发布与查询,有效地解决了传统Presence业务提供中的单点失效和热点效应问题。本文详细描述了这种业务提供方法的系统结构、业务流程和信令流程等,也给出了该方法的相关特点分析和总结。

Anisotropic Transport on Monolayer and Multilayer Phosphorene in the Presence of an Electric Field

We demonstrate theoretically the anisotropic quantum transport of electrons through an electric field on monolayer and multilayer phosphorene. Using the long-wavelength Hamiltonian with continuum approximation, we find that the transmission probability for transport through an electric field is an oscillating function of incident angle, electric field intensity, as well as the incident energy of electrons. By tuning the electric field intensity and incident angle, the channels can be transited from opaque to transparent. The conductance through the quantum waveguides depends sensitively on the transport direction because of the anisotropic effective mass, and the anisotropy of the conductance can be tuned by the electric field intensity and the number of layers. These behaviors provide us an efficient way to control the transport of phosphorene-based microstructures.

Differentiation of Algal Blooms and Aquatic Vegetation in Chinese Lakes Using Modified Vegetation Presence Frequency Index Method

Algal blooms in lakes have become a common global environmental problem. Nowadays, remote sensing is widely used to monitor algal blooms in lakes due to the macroscopic, fast, real-time characteristics. However, it is often difficult to distinguish between algal blooms and aquatic vegetation due to their similar spectral characteristics. In this paper, we used modified vegetation presence frequency index(VPF) based on Moderate-resolution Imaging Spectroradiometer(MODIS) imagery to distinguish algal blooms from aquatic vegetation, and analyzed the spatial and temporal variations of algal blooms and aquatic vegetation from a phenological perspective for five large natural lakes with frequent algal bloom outbreaks in China from 2019 to 2020. We simplified the VPF method to make it with a higher spatial transferability so that it could be applied to other lakes in different climatic zones. Through accuracy validation, we found that the modified VPF method can effectively distinguish between algal blooms and aquatic vegetation, and the results vary from lake to lake. The highest accuracy of 97% was achieved in Hulun Lake, where the frequency of algal outbreaks is low and the extent of aquatic vegetation is stable, while the lowest accuracy of 76% was achieved in Dianchi Lake, which is rainy in summer and the lake is small. Analyses suggests that the time period when algal blooms occur most frequently might not coincide with that when they have the largest area. However, in most cases these two are close in terms of time period. The modified VPF method has a broad scope of application, is easy to implement, and has a high practical value. Furthermore, the method could be established using only a small amount of measured data, which is useful for water quality monitoring on large spatial scales.

The Probe Transmission Spectra of^(87)Rb in an Operating Magneto-Optical Trap in the Presence of an Ionizing Laser

The influence of an ionizing laser on the pump-probe spectra of^(87)Rb over the transition 5^(2)S_(1/2),F=2→5^(2)P_(3/2),F'=3 is experimentally studied in an operating magneto-optical trap.These spectral features,including gain peak,a dispersion-like structure and absorption peak,become weak as the intensity of the ionizing laser increases.Moreover,the profiles of the absorption peak and gain peak vary as the ionizing laser intensity changes.Such results indicate that there is more than one component in the two features and that each component has different dependences on the number of^(87)Rb atoms.

High-Order Harmonic Generation in the Presence of Static Electric Field

We study the effects of the static electric field on the high-order harmonic generation(HOHG).It is found that the presence of the static electric field breaks the inversion and reflection symmetry,as a result,the HOHG spectrum exhibits a double plateau structure.Furthermore,the cutoff of the HOHG is no longer corresponding to the maximum kinetic energy the ionized electron can obtain from the laser field.Instead,it corresponds to the maximum kinetic energy of the electron with one return.