Workflow scheduling method under unbalanced conditions based on dynamic allocation algorithm

Potential game and no-regret learning game based on game theory model of cognitive radio have been analyzed. According to these algorithms, the mathematic model of advanced dynamic spectrum allocation algorithm based on potential game has been brought forward. Finally, the simulations of these algorithms have been proved that advanced dynamic spectrum allocation algorithm based on potential game has the best capacity performance. However, how to reduce the allocation cost when allocating spectrum is also a considerable problem.

In this paper, a novel multiple access scheme named DSAMA protocol is proposed for wireless ATM networks. DSAMA is the combination of reservation multiple access protocol and dynamic slot allocation algorithm. The orthogonal code is used for reservation in the DSAMA system. Hence, the packet collisions are prevented while several packets apply for reservation slot simultaneously. In addition, due to bandwidth limitation, the dynamic slot allocation algorithm with bound variable for bursty traffic is also proposed in this paper, so that the QoS of multimedia traffic is guaranteed in wireless ATM networks. A computer simulation is utilized to validate the DSAMA protocol. From the analysis and simulation results, we know that the slot utilization in the DSAMA system is higher than that of the other well-known integrated services multiple access (e.g., PRMA, PRMA++). Furthermore, the performance of bursty traffic in the DSAMA system outperforms the case without dynamic slot allocation. We are sure that DSAMA protocol is a competitive candidate to be adopted in the wireless ATM networks.

Dynamic virtual network allocation algorithms have emerged as a powerful way to control traffic and virtual link capacity for the popular multi-tenant data center. Unfortunately, the existing dynamic virtual network allocation algorithms are either suboptimal or inapplicable to cloud resident data center, which is a promising OpenFlow based multi-tenant data center offering virtual data centers to customers from the provider's substrate cloud. This paper proposes a new algorithm, which is both optimal and applicable to cloud resident data center. An existing dynamic virtual network allocation algorithm which is relevant to cloud resident data center has been analyzed and the assumption which makes the algorithm suboptimal has been relaxed. The optimization problem with the assumption relaxed has been solved to get the new dynamic virtual network allocation algorithm. Numerical experiments with a mix of delay-sensitive and throughput-sensitive traffic show that our algorithm out performs the existing one in terms of total utility meanwhile having the convergence rate nearly unchanged.

An enhanced multiple access scheme is presented for wireless ATM networks. The DSAMA (dynamic slot allocation multiple access), which was proposed by Wu et al. (see ICC97, p.1560-65, 1997), is a combination of reservation multiple access protocol and dynamic slot allocation algorithm. The slot utilization in DSAMA is higher than other existing integrated services multiple access, e.g. PRMA, etc. However, in DSAMA, it uses an orthogonal code for reservation, and the application of this orthogonal code strongly depends on the speed of a special chip, which is used to generate the orthogonal code. It requires the speed of this chip to be equal to the channel rate. Unfortunately, this will limit the application range of this MAC scheme. We present a new reservation method from a more general point of view, which makes the MAC protocol free from the hardware. By using an orthogonal address code and a new RR slot, the collision rate of the W-cell is reduced to a very low level. In addition, due to the limitation of the bandwidth available in the wireless network, we propose a more effective dynamic slot allocation algorithm. With a more exact boundary variable and a new allocation mechanism, we obtain a higher statistical multiplexing gain.

Relay Based Cellular Networks (RBCNs) are a key development in cellular networking technology. However, because of ever increasing demand and base station failure, RBCNs still suffer from user congestion and low resilience problems. This paper proposes two competing solutions: dynamic frequency allocation and antenna tilting to those problems. Firstly a new dynamic fractional frequency allocation algorithm and a heuristic antenna tilting algorithm are designed. The comparative benefits of each algorithm are investigated. Secondly, the additional benefits of applying the two algorithms sequentially or iteratively are evaluated. The benefits of iteratively integrating the two algorithms are more interesting. Such integration solution allows the two algorithms to be applied cooperatively. The evaluations are based on high demand scenarios and base station failure scenarios. The results show that for the high demand scenarios the new dynamic fractional frequency allocation algorithm is very powerful, and the advantage of antenna tilting is not large though present. However, for the BS failure case there is a marked additional benefit in antenna tilting. The integrated solution achieves significantly more benefit than simple sequential application of the two algorithms.

In this paper we present a yaw stabilization scheme for an automotive vehicle, that has been implemented in a realistic nonlinear multi body vehicle simulation environment. The stabilization strategy is based on two modules independent in design, a high level module that deals with the motion control objective and a low level module that deals with the actuator control allocation. The high level module consists of yaw-rate reference generator and high level controller that provides the low level control allocation module with a desired torque about the yaw axis. The task of the low level module is to command the individual brakes, the longitudinal clamping force, such that the actual torque about the yaw axis tends to the desired torque. These commands are generated by a dynamic control allocation algorithm that also takes actuator constraints and uncertainty in the tyre-road friction model into consideration. Simulation cases where the tyre-road friction parameter was considered both known and unknown, show that the control scheme stabilizes the vehicle in extreme manoeuvres where the nonlinear vehicle yaw dynamics otherwise becomes unstable in the sense of over or under-steering.

In this paper, a dynamic resource allocation algorithm to satisfy the packet delay requirements for real-time services, while maximizing the system capacity in multiuser orthogonal frequency division multiplexing (OFDM) systems is discussed. Our proposed cross-layer algorithm, called Joint Dynamic Subcarrier Allocation and Flow Control (DSA-FC) algorithm, consists of two interactive components. In the medium access control (MAC) layer, the users' expected transmission rates in terms of the number of subcarriers per symbol and their corresponding transmission priorities are evaluated. With the subcarrier gain information of each user, the physical (PHY) layer subcarrier allocation is optimally designed to satisfy the users' requirements under the system signal-to-noise ratio (SNR) and power constraints. In a system where the number of active users changes dynamically, the MAC-layer congestion control and removal schemes can guarantee the quality of service (QoS) of the existing users in the system and fully utilize the bandwidth resource. The proposed algorithm combines these two components, and the numerical results show that it significantly improves the system performance in terms of the bandwidth efficiency and delay performance for real-time services.

This paper makes two contributions. First, we introduce a model for evaluating the performance of data allocation and replication algorithms in distributed databases. The model is comprehensive in the sense that it accounts for I/O cost, for communication cost, and, because of reliability considerations, for limits on the minimum number of copies of the object. The model captures existing replica-management algorithms, such as read-one-write-all, quorum-consensus, etc. These algorithms are static in the sense that, in the absence of failures, the copies of each object are allocated to a fixed set of processors. In modern distributed databases, particularly in mobile computing environments, processors will dynamically store objects in their local database and will relinquish them. Therefore, as a second contribution of this paper, we introduce an algorithm for automatic dynamic allocation of replicas to processors. Then, using the new model, we compare the performance of the traditional read-one-write-all static allocation algorithm to the performance of the dynamic allocation algorithm. As a result, we obtain the relationship between the communication cost and I/O cost for which static allocation is superior to dynamic allocation, and the relationships for which dynamic allocation is superior.

This paper examines a cipher system for security in tactical network, plus an interleaving scheme is applied to the ciphered information to enhance the transmission performance over a fading channel. Experimental results showed that the BER performance of the proposed efficient interleaving scheme is higher than that of the fixed interleaving depth scheme. Of particular note is that the dynamic allocation algorithm (DAA, non-fixed interleaving depth) reduces degraded error bits by up to 53%, compared with static allocation algorithm (SAA, fixed interleaved depth) of depth 120 in 420MHz.

An efficient interleaving algorithm is applied to reduce the loss of ciphered information when a cipher system transmits over a wireless fading channel environment. As such, a new scheme for deciding the interleaving depth over a wireless environment is described. Simulations confirm that the proposed effective algorithm with a variable interleaving depth produces a better performance over a fading channel than a static depth algorithm with a fixed interleaving depth. Experimental results showed that the BER performance of the proposed efficient interleaving scheme was higher than that of the fixed interleaving depth scheme. Of particular note is that the dynamic allocation algorithm (DAA) reduces degraded error bits by up to 51.5%, compared with static allocation algorithm (SAA) of depth 48 in 224MHz.

An interleaving algorithm is applied to reduce the loss of ciphered information when a cipher system transmits over a wireless security environment. As such, a new scheme for deciding the interleaving depth over a wireless mobile environment is described. Simulations confirm that the proposed dynamic allocation algorithm (DAA) with a non-fixed interleaving depth produced a better performance over a fading channel than a static allocation algorithm (SAA) with a fixed interleaving depth.KeywordsFading ChannelStream CipherTransmission PerformanceSymbol Error RateBurst ErrorThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

This paper presents a fully decentralized just-in-time workflow scheduling method in a P2P Grid system. The proposed solution allows each peer node to autonomously dispatch inter-dependent tasks of workflows to run on geographically distributed computers. To reduce the workflow completion time and enhance the overall execution efficiency, not only does each node perform as a scheduler to distribute its tasks to execution nodes (or resource nodes), but the resource nodes will also set the execution priorities for the received tasks. By taking into account the unpredictability of tasks' finish time, we devise an efficient task scheduling heuristic, namely dynamic shortest makespan first (DSMF), which could be applied at both scheduling phases for determining the priority of the workflow tasks. We compare the performance of the proposed algorithm against seven other heuristics by simulation. Our algorithm achieves 20%~60% reduction on the average completion time and 37.5%~90% improvement on the average workflow execution efficiency over other decentralized algorithms.

Subject of Research. The paper presents the study of vulnerability exploitation techniques in the implementation of dynamic memory allocation algorithms (glibc library allocator): Poisoned Null-byte, Overlapped Chunks, Fastbin Attack,Unsafe Unlink, House of Einherjar, House of Force, House of Spirit, House of Lore, Unsorted Bin Attack. Examples of vulnerability exploitation code and classification of the presented techniques are given in accordance with the Common Weakness Enumeration list. The modern methods and means of vulnerabilities detection are studied; their advantages and disadvantages are shown using the Heap Hopper framework as an example. Modern methods of appropriate software verification are considered. Method. The proposed software verification method combines the approaches of static analysis and symbolic execution using an accurate model of algorithms for dynamic memory allocation. In the compilation process of program being tested, the Kripke structure is created. Dynamic memory vulnerabilities are described by temporal logic formulas. The resulting structure and formulas are passed at the input of the model checking algorithm. Concrete-symbolic execution of the assembled binary file is performed. Vulnerability conditions expressed in the form of propositional logic formulas are checked for symbolic execution paths. Main Results. The practical use of the proposed approach to detection of dynamic memory vulnerabilities in software applications is shown. Symbolic execution is implemented in the form of a low-level debugger, which reduces the operating time of algorithms due to the execution of the application being tested on a real processor. Practical Relevance. The paper presents an integrated approach for solving the problem of automatic vulnerabilities detecting at different stages of the software development life cycle. This approach is applicable for verification of the similar implementations of dynamic memory allocators, such as ptmalloc, dlmalloc, tcmalloc, jemalloc and musl.

Recently, an increasing number of public cloud vendors added Containers as a Service (CaaS) to their service portfolio. This is an adequate answer to the growing popularity of Docker, a software technology allowing Linux containers to run independently on a host in an isolated environment. As any software can be deployed in a container, the nature of containers differs and thus assorted allocation and orchestration approaches are needed for their effective execution. In this paper, we focus on containers whose execution value for end users varies over time. A baseline and two dynamic allocation algorithms are proposed and compared with the default Docker scheduling algorithm. Experiments show that the proposed approach can increase the total value obtained from a workload up to three times depending on the workload heaviness. It is also demonstrated that the algorithms scale well with the growing number of nodes in a cloud.

To solve the problem of drone demand for “last mile” distribution, many factors such as drone performance, airspace environment and transportation tasks are considered. The objective function is to minimize transportation cost with a UAV demand model. Dynamic allocation algorithm can calculate the optimal demand on the drone. The actual delivery data and low-altitude flight conditions in a certain area are analyzed as examples. The results show that the optimal load of drones is 20kg under the initial parameters, and the optimal loads of drones are 20kg and 25kg when use different drones to delivery together. The method proposed in this paper can not only calculate the demand on unmanned aerial vehicles in this area within milliseconds, but also provide flexible demand schemes when styles of drones, the airspace open-door policies and the transportation demand vary.