摘要 :
Ucam, the digital video surveillance system of Chungwha Telecom, is composed of several servers, such as NC server, relay server, event server and web server, etc. Based on the framework, it can receive the video streaming from di...
展开
Ucam, the digital video surveillance system of Chungwha Telecom, is composed of several servers, such as NC server, relay server, event server and web server, etc. Based on the framework, it can receive the video streaming from different resources such as network cameras, video encoders and video phones, and can broadcast easily to various user clients such as personal computers, IPTVs, 3G Mobile phones, video phones and smart mobile devices. This system is constructed on the internet, UMTS and NGN, and supports many kinds of protocols. It's an integrated system which is stable, operational and easy-to-use.
收起
摘要 :
We explore settings where it is necessary (due to physical or operational constraints) or desirable (due to synergies or ease of implementation) to assign resources to tasks in a synchronous manner. We model the system as a queuei...
展开
We explore settings where it is necessary (due to physical or operational constraints) or desirable (due to synergies or ease of implementation) to assign resources to tasks in a synchronous manner. We model the system as a queueing network with flexible servers and introduce the notion of a configuration to address the synchronous assignment of servers. This allows for a unified approach to determine the effects of resource synchronization, covering a wide range of problems in the literature. The maximal capacity of the system is given by the solution of a linear programming problem that also provides the optimal fractions of time the servers should spend in different configurations. This is used as a basis for constructing policies that have capacity arbitrarily close to the maximal capacity. We contrast synchronous server assignment with an asynchronous approach (focusing on independently scheduling individual servers rather than configurations) and show that synchronous server assignment is attractive with respect to applicability (it can capture constraints on server assignment and synergies among servers), implementation (it may have significantly fewer combinations of server allocations), and capacity (when both are applicable, asynchronous and synchronous server assignment will yield the same maximal capacity). Finally, we illustrate our modeling framework using several examples.
收起
摘要 :
Ucam Surveillance System of Chunghwa Telecom is an application in the field of Digital Video Surveillance System. After installing this service, customers can use PCs or 3G phones to visit the website of Ucam Surveillance System a...
展开
Ucam Surveillance System of Chunghwa Telecom is an application in the field of Digital Video Surveillance System. After installing this service, customers can use PCs or 3G phones to visit the website of Ucam Surveillance System and view the real-time image of IP Cameras that are installed in specific location. No matter whether the service is applied to the field of security guard or home care, customers are able to view the realtime streaming video of IP Cameras instantly through Ucam Surveillance System. In addition, the streaming video will be saved as record files if there are any events triggered by surrounding sensors of IP Cameras. Ucam Surveillance System provides those event record files for customers to view anytime on demand.
收起
摘要 :
In network system, there are several Open source servers such as DNS, Mail, FTP, Web and SIP. To maintain a secure network environment every server administrator follows an effective method for controlling and operating the differ...
展开
In network system, there are several Open source servers such as DNS, Mail, FTP, Web and SIP. To maintain a secure network environment every server administrator follows an effective method for controlling and operating the different servers and protect them from several attacks because Security is the main issue for networking system In this research, we established a secure environment for open source based servers using packet filtering firewall tools known as iptables. To protect the open source servers from external attack we have applied some rules at Linux iptables on the basis of respective port numbers, allowing and disallowing particular IP address or IP addresses with subnet for the important protocols like TCP, UDP, RTP and ICMP. After applying rules on protocols, we have used a popular simulation software or network protocol analyzer known as Wireshark for checking how the iptables rules are work and shows the changes before and after applying rules. We have also deployed the security rules for SIP server which are also be applicable for other servers like DNS, SMTP, POP3, FTP, web and proxy server according to their service port. After applying all the rules in different servers we have got better result regarding security performance and servers are more secured then previous.
收起
摘要 :
Many services on the Internet are provided by multiple identical servers in order to improve performance and robustness. The number, the location and the distribution of servers affect the performance and reliability of a service....
展开
Many services on the Internet are provided by multiple identical servers in order to improve performance and robustness. The number, the location and the distribution of servers affect the performance and reliability of a service. The server placement is, however, often determined based on the empirical knowledge of the administrators. This paper investigates issues of the server placement in terms of the service performance and the server load. We identify that a server selection mechanism plays an important role in server placement, and thus, evaluate different server selection algorithms. The result shows that it is essential to the robustness of a service to employ a mechanism which distributes service requests to the servers according to the measured response time of each server. As a case study, we evaluate the server selection mechanisms employed by different DNS (Domain Name System) implementations. Then, we show the effects of the different server selection algorithms using root-server measurements taken at different locations around the world.
收起
摘要 :
Motivated by an industry example, we study a two-station serial system in which we allocate flexible servers in order to maximize throughput. We investigate two cases which are different in the way that servers work together when ...
展开
Motivated by an industry example, we study a two-station serial system in which we allocate flexible servers in order to maximize throughput. We investigate two cases which are different in the way that servers work together when at the same station; namely collab-oratively or non-collaboratively. For the collaborative case we prove the optimal policy to be such that the servers work together at a single station at any point in time. In addition to the policy being state-dependent, it also follows a switching-curve structure. In the non-collaborative case, on the other hand, it may be optimal to allocate servers to different stations. Some numerical examples and results regarding policy assignments, switching curves, and system throughput are presented.
收起
摘要 :
In a large Scale streaming webcast, we must distribute streaming servers on the Internet. Then, a new problem arises regarding how to navigate requests to one of apropriate servers, In this paper, we present a new server selection...
展开
In a large Scale streaming webcast, we must distribute streaming servers on the Internet. Then, a new problem arises regarding how to navigate requests to one of apropriate servers, In this paper, we present a new server selection mechanism. This system refers routing information, and is based on DNS servers. It is independent of servers and clients. We evaluate the system in a lunar eclipse live streaming at 10 January, 2001.
收起
摘要 :
Consider a firm that operates a make-to-order serial production system and employs a cross-trained workforce. We model such a firm as a tandem queuing system in which flexible servers can be allocated across stations, and assume t...
展开
Consider a firm that operates a make-to-order serial production system and employs a cross-trained workforce. We model such a firm as a tandem queuing system in which flexible servers can be allocated across stations, and assume that a switching cost is charged when servers move between stations. We show that even in the two-station two-server case the optimal policy follows a complex state-dependent structure that may be difficult to implement in practice. We propose three alternate heuristic policies and assess their performance. We show that a simpler policy which only moves one server can achieve close to optimal results.
收起
摘要 :
Database-based web page which uses IIS4.0 + ASP + ADO + SQL7.0 is briefly introduced. It has been successfully used in E-commerce, bulletin board system and chat room, and so on in the web site of Computer Center Hudong Campus, To...
展开
Database-based web page which uses IIS4.0 + ASP + ADO + SQL7.0 is briefly introduced. It has been successfully used in E-commerce, bulletin board system and chat room, and so on in the web site of Computer Center Hudong Campus, Tongji University. With the strong development trend of internet, the requirements on web page's functions are higher and higher. In the E-commerce application, database-based web pages are glamorous. Various database-based web page solutions come out. Among them, we think better solution is: IIS4.0 + ASP + ADO + SQL7.0. The reasons are as following: First of all, this solution needs internet information server to provide web server function like IIS4.0 Secondly, it needs web control language that can run on the internet server and can be used to respond users' request and can access back-end database through a database interface like ASP. In addition, it needs a control-ware interface that makes program be able to access database like ADO. Finally, it needs a back-end database like SQL7.0.
收起
摘要 :
Daily work in molecular biology presently depends on a large number of computational tools. An in-depth, large-scale study of that 'ecosystem' of Web tools, its characteristics, interconnectivity, patterns of usage/citation, tempo...
展开
Daily work in molecular biology presently depends on a large number of computational tools. An in-depth, large-scale study of that 'ecosystem' of Web tools, its characteristics, interconnectivity, patterns of usage/citation, temporal evolution and rate of decay is crucial for understanding the forces that shape it and for informing initiatives aimed at its funding, longterm maintenance and improvement. In particular, the long-term maintenance of these tools is compromised because of their specific development model. Hundreds of published studies become irreproducible de facto, as the software tools used to conduct them become unavailable. In this study, we present a large-scale survey of >5400 publications describing Web servers within the two main bibliographic resources for disseminating new software developments in molecular biology. For all these servers, we studied their citation patterns, the subjects they address, their citation networks and the temporal evolution of these factors. We also analysed how these factors affect the availability of these servers (whether they are alive). Our results show that this ecosystem of tools is highly interconnected and adapts to the 'trendy' subjects in every moment. The servers present characteristic temporal patterns of citation/usage, and there is a worrying rate of server 'death', which is influenced by factors such as the server popularity and the institutions that hosts it. These results can inform initiatives aimed at the long-term maintenance of these resources.
收起
原文获取