An Improved Grid Security Infrastructure by Trusted Computing

Current delegation mechanism of grid security infrastructure （GSI） can＇t satisfy the requirement of dynamic, distributed and practical security in grid virtual organization. To improve this situation, a TC-enabled GSI is discussed in this paper. With TC-enabled GSI, a practical delegation solution is proposed in this paper through enforcing fine granularity policy over distributed platforms with the emerging trusted computing technologies. Here trusted platform module is treated as a tamper-resistance module to improve grid security infrastructure. With the implement of Project Daonity, it is demonstrated that the solution could gain dynamic and distributed security in grid environment.     

Power cost minimization in data centers Via Lyapunov optimization①

With the advent of big data , the demand for computing has been increasing in a very large scale for the past decade , so geographically distributed data centers are erected in the direction of cloud computing development .A Lyapunov optimization approach is considered for the problem of minimi-zing energy cost for distributed Internet data centers (IDCs).By capturing the power cost of servers and cooling systems , the Lyapunov optimization technique is formulated to design a decisive strategy that offers provable power cost minimization and QoS guarantees .The algorithm performance and ef-fectiveness are validated via simulations driven by real world traces .     

Performance Improvement of Distributed Systems by Autotuning of the Configuration Parameters

The performance of distributed computing systems is partially dependent on configuration parameters recorded in configuration files. Evolutionary strategies, with their ability to have a global view of the structural information, have been shown to effectively improve performance. However, most of these methods consume too much measurement time. This paper introduces an ordinal optimization based strategy combined with a back propagation neural network for autotuning of the configuration parameters. The strategy was first proposed in the automation community for complex manufacturing system optimization and is customized here for improving distributed system performance. The method is compared with the covariance matrix algorithm. Tests using a real distributed system with three-tier servers show that the strategy reduces the testing time by 40% on average at a reasonable performance cost.     

An architecture for mobile database management system

In order to design a new kind of mobile database management system (DBMS)more suitable for mobile computing than the existent DBMS, the essence of database systems in mobile computing is analyzed. An opinion is introduced that the mobile database is a kind of dynamic distributed database, and the concept of virtual servers to translate the clients' mobility to the servers' mobility is proposed. Based on these opinions, a kind of architecture of mobile DBMS, which is of versatility, is presented. The architecture is composed of a virtual server and a local DBMS,the virtual server is the kernel of the architecture and its functions are described. Eventually,the server kernel of a mobile DBMS prototype is illustrated.     

Dynamic overlapped spectrum allocation based on potential game in cognitive radio networks

In order to make full use of wireless spectrum resources,the behavior of cognitive radio （CR）for dynamic spectrum allocation is analyzed based on the game theoretic framework.The traditional spectrum allocation schemes consider the spectrum allocation among independent frequency bands only,without taking into account mutually overlapped frequency bands.For this reason,an optimal allocation etiquette is defined to promote the cross characteristic of the frequency bands in a dynamic spectrum allocation model.New interference operator and interference temperature constraints are introduced in order to realize calculation of the interference,and the corresponding spectrum allocation scenario can be further formulated as a potential game.Based on the characteristic of dynamic selection using the game theory and the interference avoidance rule of interference temperature,the robustness of CR networks is increased and the scenario is more suitable for the dynamic changing of actual wireless communication and energy saving communication systems.Simulation results show that the signal to interference and noise ratio （SINR） level can be significantly improved through the optimal allocation of any available spectrum.The utilization rate of spectrum and throughput of overall CR networks are increased by fully utilizing the spectrum resources in the dynamic spectrum allocation model.     

Resources Allocation Schemas for Web Information Monitoring

The web is an extremely dynamic world where information is updated even every second. A web information monitoring system fetches information from the web continuously and finds changes by comparing two versions of the same page. The updating of a specific web page is modeled as a Poisson process with parameter to indicate the change frequency. As the amount of computing resources is limited, it is necessary to find some policies for reducing the overall change-detection time. Different allocation schemas are evaluated experimentally to find out which one is the most suitable for the web information monitoring problem. The experimental data shows the runtime characteristics of the overall system performance and the relationship to the total amount of resources.     

A Loosely Coupled Control Architecture Based on Agent and CORBA for Multiple Robots

With the rapid development of information technology, adopting advanced distributed computing technology to construct robot control system is becoming an effective approach gradually.This paper proposes a distributed loosely coupled software architecture based on Agent and CORBA to control multiple robots. This model provides the robot user with agent control units at the semantic level and CORBA provides function interfaces to agent at the syntax level, which shows a good adaptability, flexibility and transparence.     

Parallel scheduling strategy of web-based spatial computing tasks in multi-core environment

In order to improve the concurrent access performance of the web-based spatial computing system in cluster,a parallel scheduling strategy based on the multi-core environment is proposed,which includes two levels of parallel processing mechanisms.One is that it can evenly allocate tasks to each server node in the cluster and the other is that it can implement the load balancing inside a server node.Based on the strategy,a new web-based spatial computing model is designed in this paper,in which,a task response ratio calculation method,a request queue buffer mechanism and a thread scheduling strategy are focused on.Experimental results show that the new model can fully use the multi-core computing advantage of each server node in the concurrent access environment and improve the average hits per second,average I/O Hits,CPU utilization and throughput.Using speed-up ratio to analyze the traditional model and the new one,the result shows that the new model has the best performance.The performance of the multi-core server nodes in the cluster is optimized; the resource utilization and the parallel processing capabilities are enhanced.The more CPU cores you have,the higher parallel processing capabilities will be obtained.     

UniNet Description of Dining Philosopher Problem

The UniNet specification of Dining Philosopher Problem we presents not only is graphic and intuitionistic but also explicitly indicates the In the specification, static semantics and the the static properties are dynamic semantics. the recorder of the dynamic properties, and the dynamic properties are the track of the static properties change. Accordingly, Dining Philosopher Problem is formally verified by UniNet. Furthermore, the procedure of properties＇ verification is implemented through the graphic-related computing style.     

Data Integration Strategy for Database Grids Based on P2P Framework

The differences between the data integration of a dynamic database grid （DBG） and that of a distributed database system are analyzed, and three kinds of data integration strategies are given on the background of DBG based on Peer to Peer （P2P） framework, including the centralized data integration （CDI） strategy, the distributed data integration （DDI） strategy and the filter-based data integration （FDDI） strategy. CDI calls all the database grid services （DGSs） at a single node, DDI disperses the DGSs to multiple nodes, while FDDI schedules the data integration nodes based on filtering the keywords returned from DGSs. The performance of these three integration strategies are compared with and analyzed by simulation experiments. FDDI is more evident for filtering the keywords with data redundancy increasing. Through the reduction of large amount of data transportation, it effectively shortens the executing time for the task and improves its efficiency.     

Hybrid Dynamic Modeling and Control of Molten Carbonate Fuel Cell Stack Shutdown

A hybrid automaton modeling approach that incorporates state space partitioning, phase dynamic modeling and control law synthesis by control strategy is utilized to develop a hybrid automaton model of molten carbonate fuel cell （MCFC） stack shutdown. The shutdown operation is divided into several phases and their boundaries are decided according to a control strategy, which is a set of specifications about the dynamics of MCFC stack during shutdown. According to the control strategy, the specification of increasing stack temperature is satisfied in a phase that can be modeled accurately. The model for phase that has complex dynamic is approximated. The duration of this kind of phase is decreased to minimize the error caused by model approximation.     

The Dynamic Evaluation of Enterprise''''s Strategy Based on Rough Set Theory

This paper presents dynamic evaluation of enterprise's strategy which is suitable for dealing with the complex and dynamic problems of strategic evaluation. Rough Set Theory is a powerful mathematical tool to handle vagueness and uncertainty of dynamic evaluation. By the application of Rough Set Theory, this paper computes the significance and weights of each evaluation criterion and helps to lay evaluation emphasis on the main and effective criteria. From the reduced decision table, evaluators can get decision rules which direct them to give judgment or suggestion of strategy. The whole evaluation process is decided by data, so the results are certain and reasonable.     

Trust Based Pervasive Computing

Pervasive computing environment is a distributed and mobile space. Trust relationship must be established and ensured between devices and the systems in the pervasive computing environment. The trusted computing （TC） technology introduced by trusted computing group is a distributed-system-wide approach to the provisions of integrity protection of resources. The TC＇s notion of trust and security can be described as conformed system behaviors of a platform environment such that the conformation can be attested to a remote challenger. In this paper the trust requirements in a pervasive/ubiquitous environment are analyzed. Then security schemes for the pervasive computing are proposed using primitives offered by TC technology.     

Maintaining consistency based on timely updating records list in workflow data

In order to settle the problem of workflow data consis-tency under the distributed environment, an invalidation strategy based-on timely updating record list is put forward. The strategy adopting the method of updating the records list and the recovery mechanism of updating message proves the classical invalidation strategy. When the request cycle of duplication is too long, the strategy uses the method of updating the records list to pause for sending updating message; when the long cycle duplication is requested again, it uses the recovery mechanism to resume the updating message. This strategy not only ensures the consistency of the workflow data, but also reduces the unnecessary network traffic. From theoretical comparison with those common strategies, the unnecessary network traffic of this strategy is fewer and more stable. The simulation results validate this conclusion.     

An optimal resource provision policy in cloud computing based on customer profiles

Conventional resource provision algorithms focus on how to maximize resource utilization and meet a fixed constraint of response time which be written in service level agreement(SLA).Unfortunately,the expected response time is highly variable and it is usually longer than the value of SLA.So,it leads to a poor resource utilization and unnecessary servers migration.We develop a framework for customer-driven dynamic resource allocation in cloud computing.Termed CDSMS(customer-driven service manage system),and the framework’s contributions are twofold.First,it can reduce the total migration times by adjusting the value of parameters of response time dynamically according to customers’profiles.Second,it can choose a best resource provision algorithm automatically in different scenarios to improve resource utilization.Finally,we perform a serious experiment in a real cloud computing platform.Experimental results show that CDSMS provides a satisfactory solution for the prediction of expected response time and the interval period between two tasks and reduce the total resource usage cost.     

Unitary Noise and the Mermin-GHZ Game

Communication complexity is an area of classical computer science which studies how much communication is necessary to solve various distributed computational problems.Quantum information processing can be used to reduce the amount of communication required to carry out some distributed problems.We speak of pseudo-telepathy when it is able to completely eliminate the need for communication.Since it is generally very hard to perfectly implement a quantum winning strategy for a pseudo-telepathy game,quantum players are almost certain to make errors even though they use a winning strategy.After introducing a model for pseudotelepathy games,we investigate the impact of erroneously performed unitary transformations on the quantum winning strategy for the Mermin-GHZ game.The question of how strong the unitary noise can be so that quantum players would still be better than classical ones is also dealt with.     

Dynamic capabilities-based strategy innovation： a theoretical framework and empirical studies in Chinese firms

Based on investigations of 112 Chinese firms and studies on foreign leading eorporafiorm, a theo-retical framework of dynamic capabilities-based strategy innovation (SI) is put forward. Several large firms in China winning through SI were studied empirically. This paper complements previous publications on the theories of innovation and strategy. This work‘ s findings will be useful for managers interested in our approach,which highlights the importance of SI and focuses on and points out the major pitfalls in the innovation processes. Implementing the dynamic capabilities-based strategy innovation can effectively cultivate and develop core eompetences of eorporations. It is eoncluded that implementing SI is the only path for Chinese enterprise growth in the intensified competition in the knowledge economy.     

Guardband Analysis for Distributed OFDMA with User Heterogeneity

This paper presents an in-depth analysis of the interference strength and required guardband width between coexistent users for distributed orthogonal frequency division multiple access (OFDMA).In dynamic spectrum access networks,the cross-band interference between spectrally adjacent users is considered harmful with frequency guardbands inserted between spectrum blocks to eliminate the interference.However,the strength of the cross-band interference depends heavily on the user heterogeneity in different OFDM configurations.The cross-band interference due to the three user heterogeneity artifacts of power heterogeneity,sampling rate heterogeneity,and symbol length heterogeneity is investigated to determine the required guardband width.Analytical and simulation results show that the greater user heterogeneity requires larger guardbands with the sampling rate heterogeneity having the greatest effect.These results can be used to assist the design of spectrum allocation strategies.     

Improved verifiability scheme for data storage in cloud computing

In Cloud computing,data and service requests are responded by remote processes calls on huge data server clusters that are not totally trusted.The new computing pattern may cause many potential security threats.This paper explores how to ensure the integrity and correctness of data storage in cloud computing with user’s key pair.In this paper,we aim mainly at constructing of a quick data chunk verifying scheme to maintain data in data center by implementing a balance strategy of cloud computing costs,removing the heavy computing load of clients,and applying an automatic data integrity maintenance method.In our scheme,third party auditor (TPA) is kept in the scheme,for the sake of the client,to periodically check the integrity of data blocks stored in data center.Our scheme supports quick public data integrity verification and chunk redundancy strategy.Compared with the existing scheme,it takes the advantage of ocean data support and high performance.     

ANALYSIS OF DYNAMIC CHARACTERISTICS FOR RCG LINES USING THEORY OF LADDER NETWORKS

The theory of RC uniform ladder networks based upon the recurrence of voltage and cur-rent functions is extended as a vehicle to analyse the dynamic characteristics of reg lines. Meth-ods for computing the time constants and simplifying the transfer functions for reg lines are alsopresented.