Smartphone use patterns and the impact on accommodation and convergence system of the eyes among Malaysian teenagers

AIM:To determine the smartphone use patterns and effects of smartphone use on accommodation and convergence system of the eyes among Malaysian teenagers.METHODS:A total of 62 participants aged between 13 and 17y were involved.A self-administered questionnaires containing 12 items was used to evaluate the smartphone usage patterns.This was followed by an eye examination,involving a battery of accommodation and convergence assessments before and after the smartphone use.The data analysis comprised descriptive statistics,paired t-test,and correlation coefficients.RESULTS:The use of smartphones is at a high level and at an optimal distance daily,with more than 6h a day watching video films,games,and completing school projects.Majority of the participants not reported eye strain factors and eye prescription changes with the use of digital devices.The use of a smartphone continuously for 30min was found to significantly decrease amplitude of accommodation,accommodative facility,and positive relative accommodation(P<0.001).Meanwhile,the lag of accommodation parameters and negative relative accommodation increased with the use of smartphones significantly(P<0.001).The near point of convergence(NPC)and distance and near negative fusional vergence decreased significantly(P<0.001).The NPC parameter was found to have a weak negative association with the frequency of smartphone use(R=-0.276,P<0.05).CONCLUSION:Frequent and continuous use of smartphones have increased visual stress and resulted in weakness of accommodation and vergence functions.Therefore,frequent break is mandatory when using a smartphone and appropriate visual hygiene,the 20-20-20 rule(every 20min,view something 20 feet away for 20s)are required during smartphone use to maintain visual function.

Formation mechanism of fault accommodation zones under combined stress in graben basin:Implications from geomechanical modeling

A fault accommodation zone is a type of structure that is defined as regulating displacement and strain between faults structure.Increasing numbers of fault accommodation zones are being identified in graben basins,indicating the potential exploration target and petroleum accumulation areas.This study aims to analyze the formation mechanism and development of fault accommodation zones under combined stress by a numerical simulation method considering geomechanical modeling.Using three-dimensional(3-D)seismic interpretation and fractal dimension method,exampled with the Dongxin fault zone,the fault activity and fault combination pattern were conducted to quantitatively characterize the activity difference in fault accommodation zones.Combined with mechanical experiment test,a geomehcanical model was established for fault accommodation zones in a graben basin.Integrating the paleostress numerical simulations and structural physical simulation experiment,the developmental characteristics and genetic mechanism of fault accommodation zones were summarized.Influenced by multi movements and combined stresses,three significant tectonic evolution stages of the Dongxing Fault Zone(DXFZ)were distinguished:During the E_(s)^(3)sedimentary period,the large difference in the stress,strain,and rupture distribution in various faults were significant,and this stage was the key generation period for the prototype of the DXFZ,including the FAZ between large-scale faults.During the E_(s)^(2)sedimentary period,the EW-trending symmetric with opposite dipping normal faults and the NE-SW trending faults with large scale were furtherly developed.The junction area of two secondary normal faults were prone to be ruptured,performing significant period for inheriting and developing characteristics of fault accommodation zones.During the Es1 sedimentary period,the high-order faults in the DXFZ exhibited the obvious fault depressions and strike-slip activity,and the fault accommodation zones were furtherly inherited and developed.This stage was the molded and formative period of the FAZ,the low-order faults,and the depression in the DXFZ.

Principle for the Installation of Accommodation for Sick guards in Public Health Establishments in Brazzaville in the Republic of Congo

The results of scientific studies of human social facts in the field of health show that the management of a patient should involve the patient’s entourage,whatever the status or size of the health establishment.In healthcare establishments in the Congo,the following are recognised as being responsible for medical care:specialist doctors,doctors,midwives,nurses and care assistants.The patient’s family and close friends are responsible for looking after the patient and financing care.The hospital infrastructure does not provide any space for the patient warden who accompany the patient during reception and hospitalisation.This makes Congolese hospitals inefficient for patient care.How can we integrate the function of the Sick guard and the assistance of the family,in order to reduce the mortality rate and repair the harm caused to patients requiring the presence of relatives during their stay in hospital,which is considered to be a dangerous place?This article examines the functional principles for configuring the space that patient warden would occupy in the patient care system.On the basis of a documentary analysis of sociological and architectural studies of existing facilities,this article proposes a typical accommodation model with the spaces needed to ensure the well-being and effectiveness of the patient warden with the patient.These are rooms with minimum space for 2 to 4 individual beds,equipped with toilets and showers.The accommodation has a dining area,kitchen and laundry facilities.In the future,this accommodation will become part of the hospital estate and may be occupied by orderlies and patient warden recruited by the hospital administration.

SAGeLogE: A Decision Support System for Students’ Accommodation Management

SAGeLogE is the acronym of “Système d’Aide à la Gestion de Logements étudiants” which means student accommodation management support system. It’s a multi-criteria decision support system designed to manage accommodation allocation for university students. Within SAGeLogE we developed the “Minimum of Ranks” (MIRA) aggregation method. MIRA method involves the application of multi-criteria decision-making methods (MCDM) to initially obtain different ranking. Thus, we chose the Weighted Sum Method (WSM), Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) and Combined Compromise Solution (CoCoSo) methods to be implemented in SAGeLogE. To prioritize the weights of criteria, the Anality Hierarchy Process (AHP) method was used. The interest of using the MIRA method was to obtain a compromised ranking coming from these three multi-criteria decision-making methods (WSM, TOPSIS, CoCoSo). So, we know that the accommodation to be allocated to students is always lower than the number of accommodation requests received by the organization. Thus, SAGeLogE proposed a technique that makes it easier to select students ranked by the multi-criteria decision-making and MIRA methods according to a method of calculation of quota of available accommodations within university residences. Finally, university accommodation managers had a wide choice of student ranking according to the methods implemented in SAGeLogE. The SAGeLogE experiment was carried out on the site of Toamasina University in Madagascar for an academic year with 2026 student accommodation applications received. The experimentation showed the ability of SAGeLogE to achieve the result.

Coordinated planning for flexible interconnection and energy storage system in low-voltage distribution networks to improve the accommodation capacity of photovoltaic

The increasing proportion of distributed photovoltaics(DPVs)and electric vehicle charging stations in low-voltage distribution networks(LVDNs)has resulted in challenges such as distribution transformer overloads and voltage violations.To address these problems,we propose a coordinated planning method for flexible interconnections and energy storage systems(ESSs)to improve the accommodation capacity of DPVs.First,the power-transfer characteristics of flexible interconnection and ESSs are analyzed.The equipment costs of the voltage source converters(VSCs)and ESSs are also analyzed comprehensively,considering the differences in installation and maintenance costs for different installation locations.Second,a bilevel programming model is established to minimize the annual comprehensive cost and yearly total PV curtailment capacity.Within this framework,the upper-level model optimizes the installation locations and capacities of the VSCs and ESSs,whereas the lower-level model optimizes the operating power of the VSCs and ESSs.The proposed model is solved using a non-dominated sorting genetic algorithm with an elite strategy(NSGA-II).The effectiveness of the proposed planning method is validated through an actual LVDN scenario,which demonstrates its advantages in enhancing PV accommodation capacity.In addition,the economic benefits of various planning schemes with different flexible interconnection topologies and different PV grid-connected forms are quantitatively analyzed,demonstrating the adaptability of the proposed coordinated planning method.

Scheimpflug Imaging of the Anterior Eye Segment during Standardized Accommodation Stimulation in Patients with Emmetropia, Myopia and Hypermetropia

Understanding of the biomechanics of the accommodative apparatus in the eyes with different refraction is important for solving the problems of theoretical and practical ophthalmology. Purpose: To determine the changes of anterior eye segment dimensions during accommodation response in normal eyes and in patients with myopia, hypermetropia. Methods and Material: 116 eyes (56 patients aged from 18 to 30 years, refraction from -2.0 to + 2.0 D) were examined. All the patients underwent a full ophthalmological examination. The ocular anterior segment was imaged using a rotational Scheimpflug camera Pentacam HR (Oculus, Wetzlar, Germany) under non- and 3.0 D of accommodative demands. The statistical data were represented as the mean value ± standard deviation (M ± SD). The Shapiro-Wilk test was used to assess the normality distribution. Wilcoxon test was used for comparison. Results: Results showed an increase in the optical density of the crystalline lens, a pupil diameter decrease and changing of the iris profile during accommodation in all patients. An increase in the total corneal aberrations and decrease in the corneal spherical aberration were revealed only in emmetropic eyes. Conclusions: The accommodative response is a multicomponent process. Scheimpflug visualization revealed the differences in the accommodative response in normal and ametropic eyes.

Peer-to-Peer Energy Trading Method of Multi-Virtual Power Plants Based on Non-Cooperative Game

The current electricity market fails to consider the energy consumption characteristics of transaction subjects such as virtual power plants.Besides,the game relationship between transaction subjects needs to be further explored.This paper proposes a Peer-to-Peer energy trading method for multi-virtual power plants based on a non-cooperative game.Firstly,a coordinated control model of public buildings is incorporated into the scheduling framework of the virtual power plant,considering the energy consumption characteristics of users.Secondly,the utility functions of multiple virtual power plants are analyzed,and a non-cooperative game model is established to explore the game relationship between electricity sellers in the Peer-to-Peer transaction process.Finally,the influence of user energy consumption characteristics on the virtual power plant operation and the Peer-to-Peer transaction process is analyzed by case studies.Furthermore,the effect of different parameters on the Nash equilibrium point is explored,and the influence factors of Peer-to-Peer transactions between virtual power plants are summarized.According to the obtained results,compared with the central air conditioning set as constant temperature control strategy,the flexible control strategy proposed in this paper improves the market power of each VPP and the overall revenue of the VPPs.In addition,the upper limit of the service quotation of the market operator have a great impact on the transaction mode of VPPs.When the service quotation decreases gradually,the P2P transaction between VPPs is more likely to occur.

Evaluation of corneal parameter changes under different accommodative stimuli with Scheimpflug imaging-based tomography

AIM:To evaluate the reliability of measurements of corneal changes with accommodation in healthy eyes using a Scheimpflug imaging-based system and how these measurements distribute in the normal population.METHODS:Prospective,non-randomized,comparative study including 27 healthy subjects(54 eyes),including emmetropia(13 eyes),myopia(17 eyes),hyperopia(4 eyes)and astigmatism(20 eyes)groups.In all cases,a complete eye examination was performed,including the analysis of corneal changes with different accommodative stimuli(+2.00,0.00 and-3.00 D)using the Pentacam AXL system.The investigation was structured in 2 phases:repeatability analysis and characterization of accommodation-related corneal changes in healthy populations.RESULTS:In the repeatability analysis,the index of height asymmetry(IHA)showed the greatest variability with the three accommodative stimuli,being the results for the rest of parameters acceptable.The group of emmetropes showed significant differences with accommodative changes in the position of maximum keratometry(Kmax;P<0.05),whereas in the astigmatism group,significant changes were not only observed in the position of Kmax,but also in minimum corneal thickness(MCT),corneal spherical aberration,and total and low order aberration root mean square(all P<0.05).Likewise,a significant difference was found in the displacement of the X position of Kmax with+2.00 D and-3.00 D in the myopia group(P=0.033)as well as in changes with+2.00 D and-3.00 D in the magnitude of the position vector of Kmax in the emmetropia group(P<0.05).No significant changes were found between accommodative stimuli in the displacement of coordinates of MCT(P≥0.109).CONCLUSION:The position of Kmax and MCT in healthy corneas can change significantly when presenting different accommodative stimuli using the accommodation mode of the Pentacam system,with different trends in these accommodation-related corneal changes between refractive errors.Likewise,the consistency of the measurements obtained with Scheimpflug has been confirmed.

PeerIS:基于Peer-to-Peer的信息检索系统

介绍了对等计算(peer-to-peer,简称 P2P)的特征、潜在优势和应用范围,指出了当前 P2P 数据共享系统(甚至缺乏语义)和粗粒度(文件水平)共享等局限性.针对这种现状,提出了基于 P2P 的信息检索,既可充分发掘 P2P 技术的潜在优势,克服传统信息检索系统的可伸缩瓶颈等问题,又可实现 P2P 数据共享系统语义丰富和细粒度的信息检索与共享;并开发出 PeerIS:基于 P2P 的信息检索系统.描述了 PeerIS 的整体构架与节点的内部结构;重点阐述了 PeerIS 的通信机制、自配置机制、查询机制以及自适应路由机制等实现关键技术;并用实验证明了 PeerIS 的优异性.

应用于移动互联网的Peer-to-Peer关键技术

对现有的应用于移动互联网的P2P技术方面的研究进行了分析.首先介绍了P2P技术和移动互联网的概念,并提出将P2P技术应用在移动互联网所面临的挑战和应用模式.其次,分别针对集中式架构、超级节点体系架构和ad hoc架构对应用于互联网的P2P网络体系架构进行了阐述.再其次,针对移动终端的两种接入模式,分别在资源定位算法和跨层优化两个方面进行了介绍.对各关键技术的特点进行了详细的分析,指出其存在的不足.最后,对未来的工作进行了展望.

基于贝叶斯网络的Peer-to-Peer识别方法

网络业务分类与识别是网络管理、网络规划和安全的必要途径,而Peer-to-Peer(P2P)流量由于采用伪装端口、动态端口以及应用层加密,已成为业务分类与识别的主要难点.该文提出了P2P业务的精确识别方法,通过对流统计特性的分析,提取相关特征属性,应用遗传算法选取最优特征属性子集,并采用贝叶斯网络机器学习方法识别P2P流量.实验表明K2,TAN和BAN能有效快速地识别P2P业务,分类精度高达95%以上,很大程度上优于朴素贝叶斯分类和BP神经网络方法.同时该系统具有可扩展性,能够识别未知的P2P流量,并适用于实时分类识别环境.

分布式Peer-to-Peer网络Gnutella模型研究

计算机对等联网(peer-to-peernetwork,P2P)技术是目前新一代网络技术研究的活跃领域,而P2P网络模型研究是P2P网络技术研究的重要环节。该文着重介绍了Gnutella网络模型的体系结构及工作原理,分析了其优缺点。并对其未来发展改进前景进行了展望。

Internet中Peer-to-Peer应用流量测量与分析

Peer to Peer网络(简称p2p)作为一种新型的覆盖网络引起了越来越多研究者的兴趣。本文介绍了在我国进行的骨干互联网上p2p网络流量测量。与现有国外研究不同,本文的数据来源于核心路由器,因此克服了它们的缺陷。其研究集中在汇聚流中的3个周期性尖峰群、不同主机发送或接收流量的重尾分布、p2p流量的长相关特性以及提出了ADTE的估计方法来区分信令和数据流量。本文的研究也显示出Napster在p2p流中占大部分,这暗示着超级节点和阶层式拓扑较纯p2p结构潜在的优势。同时,观察到在我国p2p的流量仅占Internet总流量的1%弱,这个值跟国外的数据有很大区别。我们分析了其中的原因并希望该结论为我国p2p软件的发展提供参考。

主动peer-to-peer网络架构

针对当前peer-to-peer(P2P)网络只能通过固定的协议和服务有限地利用节点资源的弱点提出了主动P2P网络(APN)架构.结合P2P网络技术和主动网络技术,核心思想是把P2P网络的服务和协议代码封装在数据包中,随着数据包一起传送,并由需要的节点加载和执行,由此完成服务和协议的动态扩充和部署.通过在APN上部署自动代码理解和查询系统,验证了APN比现有P2P网络更能充分利用节点资源,更灵活,易于管理,同时,APN在安全性和性能方面的相对降低是可接受的.

基于Peer-to-Peer的单点登录服务研究和实现

使用Peer-to-Peer模型设计了一种新的单点登录服务模型,并在国家科技基础条件平台门户应用系统的身份认证系统中实际应用。该方案(NPSSO)把身份认证分配到多个身份认证服务器上,每个身份认证服务器均由一个单独的管理系统来管理,能够大大提高容错和抗攻击能力,并且能保证系统在用户和服务的数量上具有良好的可扩展性。最后,对该套单点登录方案进行了性能分析和相关工作的比较。

基于遗传算法的Peer-to-Peer路由算法R-GA

路由算法是制约Peer-to-Peer系统整体性能的关键因素之一。目前大多数路由算法无法保证全局收敛,而链路延迟、费用、网络带宽等现实制约因素往往在选路时被忽略。针对上述问题,提出了基于遗传算法的R-GA路由算法。通过适度函数和遗传因子,R-GA可以快速地实现全局收敛。同时将链路的延迟、费用、带宽等参数插入到适度函数中,避免了盲目路由。仿真试验的结果表明,R-GA路由算法在大规模Peer-to-Peer系统中是高效和可扩展的。

一种基于Peer-to-Peer的分布式文件共享框架

主要探讨了在基于非集中式Peer to Peer网络中实现分布式文件共享和传输管理需要考虑的主要因素，给出了基于Gnutella框架的改进之处以及实现细节，并提出了以通信自相似性和拓扑幂律分布相结合的特性模型。

基于分布式聚类的Peer-to-Peer路由算法

提出了分布式聚类算法,该算法自动对地理邻近的对等结点聚类,消除了集中式聚类算法的单点瓶颈问题,及分布式Binning算法的landmark放置问题;提出了一种基于该聚类的邻居路由算法,该算法消除了na?ve算法路由效率低、IP-snoop算法实现困难及处理开销大、directed算法需要处理超级节点失效时容错问题。实验结果表明,基于分布式聚类的Peer-to-Peer(P2P)路由算法比现有的结构化路由算法减少了近一倍的路由跳转和路由时延。

Peer-to-Peer网络中文件查询的研究

随着P2P网络应用研究的热化,文件查询即给出文件名后如何确定文件的存放位置,已经成为大规模分布式网络中最常遇到的问题之一。文件查询的效率直接影响到整个P2P网络的性能。本文从P2P网络的基本现状出发,给出了目前文件查询在非结构化,结构化和松散结构化P2P网络中的解决方案并进行了深入分析和比较。文章最后指出了目前P2P网络中文件查询算法的缺点和今后的研究方向。

基于Region的多层结构Peer-to-Peer网络模型与搜索算法研究

以小世界模型为理论基础,以 Region 为基本逻辑管理单位,按用户需求和共享目的组织 Region。提出了基于 Region 的多层结构 Peer-to-Peer 网络模型和构造规则,给出了 Region 的划分策略和数学模型,证明了模型的正确和合理性;对模型中的层和域、中心节点、普通节点和汇聚点进行了明确的定义,给出了节点加入、离开、中心节点选取策略和算法描述;使定位某种服务的工作量和查询范围从网络中的所有结点数降低到 Region 的节点数,有效地防止了恶意请求引发的洪,网络系统开销为常数。模拟分析表明,该模型可有效解决可扩展性、性能与效率不高问题,且网络规模越大,其综合性能的优越性越明显,因此,模型是合理有效的。