The allocation problem is known to be NP-Hard in the most general case where both the number of modules and the number of processors is arbitrary, and it is also Np-Complete in some of the restricted cases. Also, the general scheduling problem, where no restrictions are imposed on the interconnection structure between modules, on the modules processing time and on the number of parallel processors, is NP-Hard in the strong sense. Even under some restrictions, the scheduling problem is NP-Hard. In some other restricted cases, it is known to be NP-Complete. In this thesis, we first review fifty ...

A well known problem with wormhole-routed packet networks is the potentially large amount of blocking that packets can experience due to link contention. Because of the very limited amount of buffering in such networks, blocked packets remain in the network and keep using network resources. Thus, blocked packets may in turn cause other packets to be blocked. This may affect a large number of packets over a large portion of the network. Proper connection management strategies and appropriate protocols must be devised to ensure that blocking of packets due to link contention is bounded. In [3], ...

Geographic Information Systems (GIS) have gone a great way since it has started as a science. GIS is making headlines in a number of disciplines and, through its advancement, has improved our ability to model our real world. In the past years the need to support the storage and retrieval of dynamic changes, which occur to our data, has increased which consequently led to the interest in spatio-temporal behavior in GIS. These years have also seen the birth of several spatio-temporal data Models, whose aim is to support this spatio-temporal behavior. The main aim behind Spatio-Temporal support is ...

This thesis deals with the modeling of comlex three-dimensional objects, and emphasizes on the Boolean operations between objects. It discusses a modification of the ray-casting method, which offers an improved performance over the regular ray-casting method. A small simulation will be performed, on a personal computer, about how to draw three-dimentional primitives and shading them using the wire-frame technique, plus performing Boolean operations between two objects using the modified version of the ray-casting method. Data structures and the main drawing algorithms that were created for this ...

In this thesis, we investigate the use of neural networks for solving the Traveling Salesman Problem (TSP). First, we review the main elements of the theory of NP-completeness. Then, we explain what makes some problems computationally intractable. We review some heuristic approaches used to provide near-optimal solutions to NP-complete problems. Then, we introduce the topic of neural networks and describe some of the most popular neural network models. We pay a special attention to a recent model, named the Hybrid Neural Network model (HNN), used for solving optimization problems and the Hybrid ...

This thesis deals with the communication network performance of the Automatic Vehicle Location (AVL) distributed database system. The Automatic Vehicle Location system is used to real-time track the movement of vehicles, traveling along a large geographical area. The full control of the movement of these vehicles requires the use of many communication systems such as Global Positioning system, Packet switching network and distributed database systems including vehicle position databases. The main goal of this thesis is to minimize the update response time in a real-time fully replicated distributed ...

The global Internet has experienced many years of sustained exponential growth doubling in size every nine months or faster [8]. Millions of users at tens of thousands of sites around the world depend on the global Internet as part of their daily work environment. This massive use of the Internet as well as the continuous interconnection of new groups arises many problems such as: packet loss, network congestion, insufficient bandwidth, increase in delay... In this thesis, we focus mainly on the problem of communication delay and bandwidth allocation. Our main goal is to find a way to minimize ...

This thesis uses the link structure of the World Wide Web as a basis to create better search engines. It focuses on the HITS algorithm, which was the first algorithm to up the link topology. HITS is implemented with slight modifications and tested with variations of its input parameters. It is also used in order to discover emerging communities in cyberspace. Other related algorithms, which use the link structure of the web as an undirected graph are described and compared with HITS. Finally, an attempt to combine link-based with text-based analysis in order to create more accurate search methods ...

Internet Multicast service extends the Internet point-to-point unicast delivery to a multi-point delivery. Multicasting means that a datagram is sent to multiple sites at more or less the same time. To support real-time multimedia, the minimization of delay without loosing the reliability of the network is required. To achieve this goal, we have proposed to change the architecture of a multicast one-stage network to a multicast hierarchical two-stage network. We have proved that by giving additional functionalities (such as back-up and error correction) to the intermediate sites (i.e. mrouters) ...