An algorithm for achieving proportional delay differentiation

We consider the implementation of the proportional delay differentiation model with adaptive waiting time priority scheduler and we address the problem of finding the appropriate scheduler differentiation parameters that achieve this model. In this paper, we propose an algorithm that can compute an analytical solution of this problem.     

The M/G/1/K blocking formula and its generalizations to state-dependent vacation systems and priority systems

The formula for the blocking probability for the finite capacity M/G/1/K in terms of the steady state occupancy probability distribution of M/G/1 and the system utilization is known [Keilson, J. Royal Statistical Soc. Serie B, 28 (1966) 190–201]. The validity of this relationship is demonstrated for a broad class of state dependent M/G/1 vacation systems and priority systems. New methods are employed which may also be of interest in their own right.This research was conducted while J. Keilson was a Senior Staff Scientist at GTE Laboratories Incorporated.     

Analysis of Wavelength-Routed Optical Burst-Switched Network Performance

This paper studies a novel scalable network architecture combining optical burst switching (OBS) with dynamic wavelength allocation to guarantee quality of service (QoS), forming a wavelength-routed optical burst-switched network. All processing and buffering functions are concentrated at the network edge and bursts are assigned to fast tuneable lasers and routed over a bufferless optical transport core using dynamic wavelength assignment. Different burst aggregation mechanisms are evaluated for a range of traffic statistics in terms of delay and packet loss rate. New network performance parameters in an analytical model quantify the advantages of dynamic wavelength allocation. The results define the operational gain achievable with dynamic wavelength assignment compared to quasi-static wavelength routed optical networks.     

A Hybrid Genetic Algorithm for Assembly Line Balancing

This paper presents a hybrid genetic algorithm for the simple assembly line problem, SALBP-1. The chromosome representation of the problem is based on random keys. The assignment of the operations to the workstations is based on a heuristic priority rule in which the priorities of the operations are defined by the chromosomes. A local search is used to improve the solution. The approach is tested on a set of problems taken from the literature and compared with other approaches. The computation results validate the effectiveness of the algorithm.     

Results of a European inter-laboratory comparison study on the determination of EU priority polycyclic aromatic hydrocarbons (PAHs) in edible vegetable oils

A collaborative study on the analysis for 15 + 1 EU priority PAHs in edible oils was organised to investigate the state-of-the-art of respective analytical methods. Three spiked vegetable oils, one contaminated native sunflower oil, and one standard solution were investigated in this study. The results of 52 laboratories using either high-performance liquid chromatography with fluorescence detection or gas chromatography with mass-selective detectors were evaluated by application of robust statistics. About 95% of the laboratories were able to quantify benzo[a]pyrene together with five other PAHs included in the commonly known list of 16 US-EPA PAHs. About 80% of the participants also quantified seven additional PAHs in most samples, two of which were benzo[b]fluoranthene and benzo[k]fluoranthene, which were also known from the EPA list. Only about 50% of the participants quantified cyclopenta[cd]pyrene, benzo[j]fluoranthene, and benzo[c]fluorene. The robust relative standard deviations of the submitted results without discrimination between the methods applied ranged between 100% for 5-methylchrysene in spiked olive oil and 11% for the same analyte in spiked sunflower oil. The results clearly showed that for these analytes the methods of analysis are not yet well established in European laboratories, and more collaborative trials are needed to promote further development and to improve the performances of the respective methods.     

Counting preimages of TCP reordering patterns

Packet reordering is an important property of network traffic that should be captured by analytical models of the Transmission Control Protocol (TCP). We study a combinatorial problem motivated by Restored [G. Istrate, A. Hansson, S. Thulasidasan, M. Marathe, C. Barrett, Semantic compression of TCP traces, in: F. Boavida (Ed.), Proceedings of the Fifth IFIP NETWORKING Conference, in: Lecture Notes in Computer Science, vol. 3976, Springer-Verlag, 2006, pp. 123-135], a TCP modeling methodology that incorporates information about packet dynamics. A significant component of this model is a many-to-one mapping B that transforms sequences of packet IDs into buffer sequences in a manner that is compatible with TCP semantics. We obtain the following results:

•

We give an easy necessary and sufficient condition for an input sequence W to be valid (i.e. A∈B⁻¹(W) for some permutation A of {1,2,…,n}), and a linear time algorithm that, given a valid buffer sequence W of length n, constructs a permutation A in the preimage of W.

•

We show that the problem of counting the number of permutations in B⁻¹(W) has a polynomial time algorithm.

•

We also show how to extend these results to sequences of IDs that contain repeated packets.

     

H∞ control of a class of networked control systems with time delay and packet dropout

This paper studies the H-infinity control issue for a class of networked control systems (NCSs) with time delay and packet dropout. The state feedback closed-loop NCS is modeled as a discrete-time switched system. Through using a Lyapunov function, a sufficient condition is obtained, under which the system is exponential stability with a desired H-infinity disturbance attenuation level. The designed H-infinity controller is obtained by solving a set of linear matrix inequalities. An illustrative example is presented to demonstrate the effectiveness of the proposed method.     

An efficient packet parser architecture for software-defined 5G networks

Software-defined networks (SDN) has emerged with the capability to program in order to enhance flexibility, management, and testing of new ideas in the next generation of networks by removing current network limitations. Network virtualization and functionalization are critical elements supporting the delivery of future network services, especially in 5G networks. With the integration of virtualization and functionalization, network resources can be provisioned on-demand, and network service functions can be composed and chained dynamically to cater to various requirements. 5G networks are expected to rely heavily on SDN, which has been widely applied in core network design. To have a software-defined 5G network, not only is new spectrum and interface needed from SDN, but also a programmable and efficient hardware infrastructure is required. Admittedly, hardware components and infrastructure play an important role in supporting 5G networks. In other words, the software-defined 5G network data plane must have the required flexibility and programmability to support upcoming needs and technologies. Technological solutions need to respond to actual requests in infrastructure. Packet parsers in the data plane of software-defined 5G networks are one of the most important components because of the variation in the type of network headers and protocols. Each SDN switch needs to identify headers for processing input packets in the data plane, where the packet parser operates. Multiple implementations of packet parsers have been done on different substrates that occupy large hardware resources and areas on chip. However, they are not suitable for software-defined 5G networks. Certain architectures have been presented for packet parsing, aimed at accelerating the process of header parsing, however no attention has been paid toward reducing the area and the volume of the needed hardware resources and programmability in the data plane. This paper presents a new and efficient architecture for packet parsers on Field Programmable Gate Arrays (FPGA), called Efficient FPGA Packet Parser (EFPP) in a designed software-defined 5G network. This architecture emphasizes the removal of Ternary Content Addressable Memory (TCAM) to decrease hardware resources and efficiency in the data plane. Moreover, this architecture uses the chip’s processing speed and reconfiguration capabilities to support new protocols and network headers while maintaining flexibilities on software-defined 5G networks. EFPP is applied to chips on FPGA Xilinx ZedBoard Zynq, and the resources consumed around 7.5% LookUp Table, 1.9% Flip-Flops, and 5.8% of the memory. EFPP was also more area efficient. According to our results, EFPP would reduce the area and volume of hardware compared to other peer works.     

Analysis of a finite buffer model with two servers and two nonpreemptive priority classes

In this paper, we analyze a finite buffer queueing model with two servers and two nonpreemptive priority service classes. The arrival streams are independent Poisson processes, and the service times of the two classes are exponentially distributed with different means. One of the two servers is reserved exclusively for one class with high priority and the other server serves the two classes according to a nonpreemptive priority service schedule. For the model, we describe its dynamic behavior by a four-dimensional continuous-time Markov process. Applying recursive approaches we present the explicit representation for the steady-state distribution of this Markov process. Then, we calculate the Laplace–Stieltjes Transform and the steady-state distribution of the actual waiting times of two classes of customers. We also give some numerical comparison results with other queueing models.