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With the development of agile optical switches, dynamic optical circuit switching has become possible and connections are set up and torn down on demand basis. The explosive growth of different traffic types such as data, voice and video requires the support of differentiated services in terms of survivability measures and timing requirements. In order to guarantee a specific level of survivability, availability-guaranteed bandwidth provisioning is considered. On the other hand, connections are set up and released for specific time durations, with sliding or fixed setup times. Connection requests arrive to the network provider with specified holding times, delay tolerances and availability requirements which need to be satisfied. Delay tolerance is defined as the maximum time which a request can tolerate before the connection is set up. Future network carriers need to meet strict SLA (Service Level Agreement) guidelines, thus guaranteeing a level of service, as well as achieving efficient resource utilization. Connection availability is an important metric to measure the quality of service (QoS) in a survivable network. It is defined as the probability that a connection will be found in the operating state at a random time in the future (Clouqueur et al., 2002). It is affected by many factors such as network component failure probabilities, failure repair times, etc. Usually, the availability target for a connection is specified in a Service Level Agreement (SLA), which is a contract between a service provider (e.g., a network operator) and one of its customers (e.g., a large institutional user of bandwidth). An SLA violation may result in a penalty to be paid by the network operator to the customer according to the contract (Grover, 1999). In order to provide the appropriate level of availability stated in the SLAs, different recovery mechanisms can be used to provision different connection requests. In this study, we consider unprotected, shared-path protected and dedicated-path protected provisioning mechanisms at the same time to satisfy different QoS requirements in a dynamic manner. Previous studies, while maximizing sharability by routing backup paths in a dynamic traffic environment, do not make any estimation on future sharability of resources. They take the current link states into consideration to choose sharable links. Reference (Tornatore et al., 2005a,b) shows that resource overbuild (RO) in shared-path protection can be decreased by exploiting the holding-time information of connections which have already been provisioned in the network. Since holding times of incoming traffic demands may be known in advance for a variety of applications, this information about the future states of the links makes the route decision more intelligent by allowing the choice of more sharable paths. In this paper, unprotected, shared-path, and dedicated-path protection techniques are used to meet the differentiated availability requirements. Recently, among the other Service Level Specifications (SLSs), many new applications are identified by known in advance holding time and delay tolerance. So, in this paper, for dynamic provisioning of availability guaranteed connections in an optical mesh network, we propose two new algorithms which exploit 1 the knowledge of connection holding times to accomplish minimum backup capacity allocation as compared to the previous holding time unaware approach and 2 the knowledge of delay tolerances to degrease the blocking probability in the conditions that the system resources are not available to satisfy the SLS demands of connection requests. Here we also propose a new routing mechanism for backup paths optimizing backup resources considering the future departure time of existing connections. In order to show the performance gain; the first proposal, AGSDP_HT (Holding time aware Availability Guaranteed Service Differentiated Provisioning) is compared by a base line algorithm AGSDP. The second proposal ADT (Availability guaranteed, service differentiated provisioning with Delay Tolerance) is compared by a base line approach which does not consider delay tolerance. For the second proposal, both algorithms dedicated protection is not used as a choice, since blocking is decreased by delay tolerance. [ABSTRACT FROM AUTHOR]

Digital Finite Impulse Response (FIR) filters are frequently used in Digital Signal Processing (DSP) by virtue of stability and easy implementation. The problem of designing the multiplier block of a digital FIR filter has received a significant amount of attention during the last decade, as the filters require a large number of multiplications, leading to excessive area, delay, and power consumption even if implemented in a full custom integrated circuit. Previous works have focused on the design of filters with minimum area by replacing the multiplication operations with constant coefficients by addition, subtraction, and shifting operations. Since shifts can be implemented with only wires in hardware, the design problem can be defined as the minimization of the number of addition/subtraction operations to implement the coefficient multiplications. This problem is generally known as the MCM problem. In the last decade, many efficient algorithms have been proposed for the MCM problem. These algorithms can be categorized in two classes: Common Subexpression Elimination (CSE) and graph-based algorithms. While the CSE algorithms basically find the common non-zero digit patterns on the representations of the constants, the graph-based algorithms are not restricted to a particular number representation and synthesize the constants iteratively by building a graph. However, in the algorithms proposed for the MCM problem, an addition/subtraction operation is assumed to be a two-input operation that is generally implemented using a Ripple Carry Adder (RCA) block yielding great latency in the implementation of MCM. In high-speed applications, particularly in DSP systems, Carry-Save Adder (CSA) blocks are preferred to RCA blocks taking into account the increase in area. Despite the large number of algorithms designed for the minimization of addition/subtraction operations based on RCAs, there are only a few algorithms proposed for the optimization of the number of CSA blocks. Although these algorithms give good results, they are based on heuristics, i.e., provide no indication on how far from the minimum their solutions are. To the best of our knowledge, there is no exact algorithm proposed for the optimization of the number of CSA blocks in MCM. In this paper, an exact CSE algorithm designed for the minimization of the number of CSA blocks is introduced. In the exact CSE algorithm, initially, all possible implementations of filter coefficients and partial terms using CSAs are found when filter coefficients are defined under a number representation, and a combinational network that represents the implementations of constants is constructed. Then, the minimization of the number of CSA blocks problem is defined as a 0-1 Integer Linear Programming (ILP) problem with a cost function to be minimized and constraints to be satisfied.… [ABSTRACT FROM AUTHOR]