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941.
Miguel Freitas 《International Journal of Parallel, Emergent and Distributed Systems》2016,31(1):20-33
This paper proposes a new microblogging architecture based on peer-to-peer networks overlays. The proposed platform comprises three mostly independent overlay networks. The first provides distributed user registration and authentication and is based on the Bitcoin protocol. The second one is a Distributed Hash Table (DHT) overlay network providing key/value storage for user resources and tracker location for the third network. The last network is a collection of possibly disjoint ‘swarms’ of followers, based on the BitTorrent protocol, which can be used for efficient near-instant notification delivery to many users. By leveraging existing and proven technologies, twister provides a new microblogging platform offering security, scalability and privacy features. A built-in mechanism provides incentive for entities that contribute processing time to run the user registration network, rewarding such entities with the privilege of sending a single unsolicited (‘promoted’) message to the entire network. The number of unsolicited messages per day is defined in order to not upset users. Security and scalability assumptions have been confirmed in a real-world deployment. 相似文献
942.
The wide availability of affordable RGB-D sensors changes the landscape of indoor scene analysis. Years of research on simultaneous localization and mapping (SLAM) have made it possible to merge multiple RGB-D images into a single point cloud and provide a 3D model for a complete indoor scene. However, these reconstructed models only have geometry information, not including semantic knowledge. The advancements in robot autonomy and capabilities for carrying out more complex tasks in unstructured environments can be greatly enhanced by endowing environment models with semantic knowledge. Towards this goal, we propose a novel approach to generate 3D semantic maps for an indoor scene. Our approach creates a 3D reconstructed map from a RGB-D image sequence firstly, then we jointly infer the semantic object category and structural class for each point of the global map. 12 object categories (e.g. walls, tables, chairs) and 4 structural classes (ground, structure, furniture and props) are labeled in the global map. In this way, we can totally understand both the object and structure information. In order to get semantic information, we compute semantic segmentation for each RGB-D image and merge the labeling results by a Dense Conditional Random Field. Different from previous techniques, we use temporal information and higher-order cliques to enforce the label consistency for each image labeling result. Our experiments demonstrate that temporal information and higher-order cliques are significant for the semantic mapping procedure and can improve the precision of the semantic mapping results. 相似文献
943.
Wail Mardini Yaser Khamayseh Abdalrhman Abdalkareem Almodawar Ehab Elmallah 《Peer-to-Peer Networking and Applications》2016,9(6):991-1004
Range of applications for Wireless Sensor Networks (WSNs) is increasing rapidly. One class of such applications is Energy-Aware Wireless Positioning Systems for situation awareness. Localization deals with determining a target node’s position in WSN by analyzing signals exchanged between nodes. Received Signal Strength Indicator (RSSI) represents the ratio between received signal power and a reference power, and is typically used to estimate distances between nodes. RSSI distance estimations are affected by many factors. This paper aims to enhance the accuracy of RSSI-based localization techniques in ZigBee Networks through studying the communication channel status between two nodes. As the network nodes are exposed to high noise levels, position estimation accuracy deteriorates. A novel adaptive localization scheme is proposed; Two-State Markov model with moving average is employed to detect unpredictable RSSI readings that may reflect badly on the estimation. The proposed scheme achieves better estimation accuracy, for example, the estimation error was reduced from 11.7 m to just 3 m using the proposed scheme. 相似文献
944.
Peng Qin Bin Dai Guan Xu Kui Wu Benxiong Huang 《Peer-to-Peer Networking and Applications》2016,9(6):1047-1059
A Peer-to-Peer (P2P) network can boost its performance if peers are provided with underlying network-layer routing topology. The task of inferring the network-layer routing topology and link performance from an end host to a set of other hosts is termed as network tomography, and it normally requires host computers to send probing messages. We design a passive network tomography method that does not require any probing messages and takes a free ride over data flows in P2P networks. It infers routing topology based on end-to-end delay correlation estimation (DCE) without requiring any synchronization or cooperation from the intermediate routers. We implement and test our method in the real world Internet environment and achieved the accuracy of 92 % in topology recovery. We also perform extensive simulation in OMNeT++ to evaluate its performance over large scale networks, showing that its topology recovery accuracy is about 95 % for large networks. 相似文献
945.
Xiao Liu Kaoru Ota Anfeng Liu Zhigang Chen 《Peer-to-Peer Networking and Applications》2016,9(4):692-711
Crowd sensing networks can be used for large scale sensing of the physical world or other information service by leveraging the available sensors on the phones. The collector hopes to collect as much as sensed data at relatively low cost. However, the sensing participants want to earn much money at low cost. This paper examines the evolutionary process among participants sensing networks and proposes an evolutionary game model to depict collaborative game phenomenon in the crowd sensing networks based on the principles of game theory in economics. A effectively incentive mechanism is established through corrected the penalty function of the game model accordance with the cooperation rates of the participant, and corrected the game times in accordance with it’s payoff. The collector controls the process of game by adjusting the price function. We find that the proposed incentive game based evolutionary model can help decision makers simulate evolutionary process under various scenarios. The crowd sensing networks structure significantly influence cooperation ratio and the total number of participant involved in the game, and the distribution of population with different game strategy. Through evolutionary game model, the manager can select an optimal price to facilitate the system reach equilibrium state quickly, and get the number of participants involved in the game. The incentive game based evolutionary model in crowd sensing networks provides valuable decision-making support to managers. 相似文献
946.
This article presents an in-depth qualitative study using a phenomenological approach to understand loneliness among elderly individuals in Malaysia. The objective of the study was to understand how the Malaysian elderly perceive and understand social isolation as well as loneliness, with the aim of identifying the factors that cause emotional loneliness among the elderly in nursing homes. In addition, this study also explored their coping strategies when dealing with loneliness. Semi-structured interviews were conducted with ten elderly participants from two different nursing homes in Kuala Lumpur and Selangor with representatives from the three major ethnic groups of Malaysia. Based on the results, there are several factors that cause the elderly to feel lonely – health factors, lack of family ties, and the lack of communication and cognitive factors, such as memory and perception. It was also found that internal (expectations and optimism) and external (work and activities) coping strategies play major roles in overcoming loneliness. In conclusion, some recommendations are made to respective party families and the government to consider when developing plans to help the elderly overcome loneliness, which could strengthen the family and social support system in Malaysia. 相似文献
947.
This research focused on determining the sociocultural factors that build the social perception of the social roles of senior citizens in Chile in the 2002–2012 period. For this purpose, public opinion was studied in newspapers El Mercurio and La Cuarta. Specialized opinion included the Senior Citizen Program of Pontificia Universidad Católica de Chile, the National Service for Senior Citizens, the Social Observatory for Aging and Old Age of Universidad de Chile, and the Society of Geriatrics and Gerontology of Chile. A comprehensive methodology was used, along with a bibliographical four-stage design. The following ten sociocultural factors were identified: Health and Quality of Life, Studies and Data, Social Images of Aging, Gerontological Concepts and Sociopolitical Participation, Gerontological Policies, Plans and Principles, Aging, Production and Gender, Institutionalization, Demographic Growth, Gerontological Training, and Exclusion and Old Age. This work suggests modifying the conceptual premise that emphasizes the inexistence of a social role for elderly people with a vision centered on the heterogeneity of social roles under permanent sociocultural construction. 相似文献
948.
Yanrong Lu Lixiang Li Haipeng Peng Yixian Yang 《Peer-to-Peer Networking and Applications》2016,9(2):449-459
The Session Initiation Protocol (SIP) as the core signaling protocol for multimedia services is receiving much attention. Authentication is becoming increasingly crucial issue when a user asks to use SIP services. Many authentication schemes for the SIP have been proposed. Very recently, Zhang et al. has presented an authentication scheme for SIP and claimed their scheme could overcome various attacks while maintaining efficiency. In this research, we illustrate that their scheme is susceptible to the insider attack and does not provide proper mutual authentication. We then propose a modified secure mutual authentication scheme to conquer the security flaws in Zhang et al.’s scheme. Through the informal and formal security analyses, we demonstrate that our scheme is resilient possible known attacks including the attacks found in Zhang et al.’s scheme. In addition, the performance analysis shows that our scheme has better efficiency in comparison with other related ECC-based authentication schemes for SIP. 相似文献
949.
In this paper, we use the concept of prospective age to illuminate patterns of aging by gender, and education in Europe. We find that, within countries, the patterns of aging of men and women with high education are comparatively similar to one another, but that the patterns of aging are quite dissimilar for men and women in the low education group. Across countries the patterns of aging become more similar as education levels increase. Thus, when we look across educational strata, we find increasing convergence in the pattern of aging both across countries and by gender within countries. The distinctive patterns of aging in the Eastern European countries are largely associated with the comparatively rapid aging of men in the low education category. If aging patterns by education persist, improvements in the education composition of Eastern European countries would result in the patterns of aging there becoming more similar to those in Western European countries. 相似文献
950.
You-bo Liu Jun-yong Liu Gareth Taylor Ting-jian Liu Jing Gou Xi Zhang 《浙江大学学报:C卷英文版》2016,17(11):1107-1121
The operational environment of today’s smart grids is becoming more complicated than ever before. A number of factors, including renewable penetration, marketization, cyber security, and hazards of nature, bring challenges and even threats to control centers. New techniques are anticipated to help dispatchers become aware of the accurate situations as they manipulate and navigate the situations as quickly as possible. To address the issues, we first introduce the background for this topic as well as the emerging technical demands of situational awareness in the dispatcher’s environment. The general concepts and technical requirements of situational awareness are then summarized, aimed at offering an overview for readers to understand the state-of-the-art progress in this area. In addition, we discuss the importance of integrating the architecture of support tools in accordance with the dispatcher’s thought process, which in fact guides correct and swift reactions in real-time operations. Finally, the prospects for situational awareness architecture are investigated with the goal of presenting situational awareness modules in an advanced and visualized manner. 相似文献