With the rapid rise in the demand for location related service, communication devices such as PDAs or cellar phones must be able to search and manage information related to the geographical location. To leverage location-related information is useful to get an in-depth perspective on environmental circumstances, such as traffic conditions or weather information. To handle the large number of information and queries communication devices generate in the current ubiquitous environment, some scalable mechanism must be required. DHTs and some overlay networks supporting range search are proposed. However, these overlay networks can not process queries of geographical region search. In this paper, we propose a overlay network called "Mill" which can efficiently manage information related to the geographical location. In DHT based overlay networks, each node has responsibility to manage a part of the whole hash table. DHTs provide scalable systems and support fast search. However, DHTs are not good at solving geographical search (range search), because hash function only supports exact match. In the Mill network, each node manages a part of ID-space calculated by "Z-ordering," which represents squire surface of the earth. This structure of ID-space enables to process region queries easily and fast. And Mill supports any scale of region search. We evaluate proposed system by using traffic infomation generator called "HAKONIWA." Simulation results show that the performance of Mill is good as well as other DHT systems. In addtion, Mill provedes more efficient region search than other overlay networks supporting range search.
We examine the delay performance of packets from constant-bit-rate (CBR) traffic whose delay is affected by nonreal-time traffic. The delay performance is analyzed by solving the 1 queue with vacations. We obtain an exact and closed form solution, hence obviating the need of any approximations or numerical Laplace inversions. We then provide various numerical results for low-bit-rate transmission links, in which packets can experience large delay. From our quantitative evaluation, we conclude that there exists an optimum packet size for a given delay bound. In extremely slow links, such as modem links, transmission control protocol (TCP) packets should be segmented to reduce the CBR delay. We therefore investigate the delay impact of TCP packet sizes as well.
Abstract-Internet-native audio-visual services are witnessing rapid development. Among these services, object-based audiovisual services are gaining importance. In 2014, we established the Software Defined Media (SDM) consortium to target new research areas and markets involving object-based digital media and Internet-by-design audio-visual environments. In this paper, we introduce the SDM architecture that virtualizes networked audio-visual services along with the development of smart buildings and smart cities using Internet of Things (IoT) devices and smart building facilities. Moreover, we design the SDM architecture as a layered architecture to promote the development of innovative applications on the basis of rapid advancements in software-defined networking (SDN). Then, we implement a prototype system based on the architecture, present the system at an exhibition, and provide it as an SDM API to application developers at hackathons. Various types of applications are developed using the API at these events. An evaluation of SDM API access shows that the prototype SDM platform effectively provides 3D audio reproducibility and interactiveness for SDM applications.
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