Adaptable concurrency control for atomic data types

With the development of the communication technology, the number of the mobile equipment grows rapidly. But how to maintain the consistency of the data in multiple devices has become an increasing prominent issue. In this passage, the SyncML RTK is introduced firstly. Based on this, a design and implementation of the synchronization server will be furtherly discussed. Moreover, an experiment about the server efficiency will be done. The experiment result shows that the design of the server is feasible.

Supporting atomic transactions and concurrency control in peer-to-peer networks is difficult because nodes may leave, crash or join at any time. We propose a transaction processing scheme for peer-to-peer networks that ensures consistency and durability by constructing the overlay from replicated state machines. Our scheme supports a mixture of pessimistic, hybrid optimistic and multiversioning concurrency control techniques to minimize the impact of replication on latency and to maximize the speed of read operations.

This research paper presents the design and implementation of a Web Server designed in C++ which is a Custom Web server that is it can be used for specific tasks which makes it faster than other open- source web servers it can also be used to meet the specific needs of a particular organization. The paper discusses the challenges faced during the development process and the solutions that were implemented to overcome them. Performance tests were conducted to evaluate the server's efficiency and effectiveness using different web applications that interact with Data Bases and external Third Party APIs, and the results demonstrate that it performs at a high level even under heavy loads. Overall, this paper provides valuable insights into the development of custom web servers and highlights the benefits of creating a tailored solution for specific organizational needs. Keywords: - Customized Web Server, Web Services, HTTP Protocols, Web Applications

Concurrency control is the activity of synchronizing operations issued by concurrent executing transactions on a shared database. The aim of this control is to provide an execution that has the same effect as a serial (non-interleaved) one. The optimistic concurrency control technique allows the transactions to execute without synchronization, relying on commit-time validation to ensure serializability. Effectiveness of the optimistic techniques depends on the conflict rate of transactions. Since different systems have various patterns of conflict and the patterns may also change over time, so applying the optimistic scheme to the entire system results in degradation of performance. In this paper, a novel algorithm is proposed that dynamically selects the optimistic or pessimistic approach based on the value of conflict rate. The proposed algorithm uses an adaptive resonance theory–based neural network in making decision for granting a lock or detection of the winner transaction. In addition, the parameters of this neural network are optimized by a modified gravitational search algorithm. On the other hand, in the real operational environments we know the writeset (WS) and readset (RS) only for a fraction of transactions set before execution. So, the proposed algorithm is designed based on optional knowledge about WS and RS of transactions. Experimental results show that the proposed hybrid concurrency control algorithm results in more than 35 % reduction in the number of aborts in high-transaction rates as compared to strict two-phase locking algorithm that is used in many commercial database systems. This improvement is 13 % as compared to pure-pessimistic approach and is more than 31 % as compared to pure-optimistic approach.

Modern JVM implementations interleave execution with compilation of “hot” methods to achieve reasonable performance. Since compilation overhead impacts the execution time of the application and induces run-time pauses, we explore offloading compilation onto a compilation server. In this article, we present the design, implementation, and evaluation of a compilation server that compiles and optimizes Java bytecodes on behalf of its clients. We show that the compilation server provides the following benefits for our benchmark programs: (i) lower execution time by reducing the compilation overhead and by enabling more aggressive optimizations; (ii) lower memory allocation by eliminating allocations due to optimizing compilation and the footprint of the optimizing compiler; (iii) lower execution time of the application due to sharing of profile information across different runs of the same application and runs of different applications. We implemented the compilation server in Jikes RVM, and our results indicate that it can reduce running time by an average of 20.5%, interruptions due to compilation by an average of 81.0%, and dynamic memory allocation by 8.6% for our benchmark programs. Simulation results indicate that our current implementation of the compilation server can handle more than 50 concurrent clients while still allowing them to outperform the best performing adaptive configuration.

We describe the design, implementation and performance of a stand-alone media server. This server is intended to be used in voice over IP systems for audio interaction with users, NAT traversal, call monitoring and media recording. Its advantage is that it is application independent, which means that it can be used by any service and for any signaling protocol. In this paper we describe the design of the server, of its control protocol and of its functionalities such as file playing, DTMF detection, RTP proxying and audio recording. For file playing, we propose an approach to schedule RTP packet transmission that overcomes the irregularity of event scheduling of the operating system and for conversation recording, we propose an original approach to synchronize media streams that allows to avoid voice overlap while recording a conversation. We have conducted many experiments on the media server. We evaluated the accuracy of the file playing timing under different load conditions, the effect of the RTP proxying on the media quality and the subjective quality of recorded conversations. The results of these experiments show the great impact of the load of the media server on the performance of its functionalities, the improvement that the packet scheduling algorithm brings to the precision of inter-departure timing, and the good subjective quality of the recorded conversation using our synchronizing approach.

This paper presents the design and implementation of the Terminal Device Driver Server (TDDS), which runs on top of Chorus microkernel at the communication connection node of the SPAX multi-computer. The correctness of our design and implementation have been proved through a variety of tests. We believe that our experiences would be very helpful to the serverization of other STREAMS-based device drivers such as networking device drivers.KeywordsProcessing NodeDevice DriverDistribute Operating SystemBlock DeviceCrossbar SwitchThese 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.

In order to realize the high precision indoor positioning system, an embedded gateway is designed for data transmission and forwarding, and the server is developed on Windows platform for storing data, obtaining and showing location information. The indoor positioning system architecture is given, focusing on the design and implementation of gateway and server. ARM11 processor is used to design a gateway. Gateway architecture and software development are introduced. A server solution is described. The results show that the designed gateway and server meet the requirements of data transmission and good positioning accuracy.

This paper describes the design and implementation of a file server for variable bit rate continuous media. Most continuous media file servers have been designed for constant bit rate streams. We address the problem of building a server where each stream may have a different bit rate and, more importantly, where the bit rate within a single stream may vary considerably. Such servers will be come increasingly more important because of Variable Bit Rate (VBR) compression standards such as MPEG-2.

This paper describes the design and implementation of a file server for variable bit rate continuous media. Most continuous media file servers have been designed for constant bit rate streams. We address the problem of building a server where each stream may have a different bit rate and, more importantly, where the bit rate within a single stream may vary considerably. Such servers will become increasingly more important because of Variable Bit Rate compression standards such as is possible with MPEG-2.

Remote control networks have become a key area of research within wireless communication technology. Zigbee technology fills the gap in the market for low-cost, low-power wireless solutions. This paper presents the design and application of a wireless sensor network web server based on the S3C2410 microcontroller and the Zigbee protocol. The server enables real-time monitoring and control of remote objects. Using a B/S architecture and modular design approach, both hardware and software components are detailed, with an emphasis on key implementation techniques. The system has been demonstrated to operate stably with excellent scalability, making it suitable for applications in smart homes, monitoring systems, industrial control, and other domains.

MODIS data are currently widely applied in the scientific research covering the global or regional in the real-time Earth observation and disaster and environmental monitoring. However, some issues such as large data volume and complex storage format impede MODIS data's direct circulation and use, and the introduction of the WCS can foster MODIS data's dissemination and application. Facing the application requirement of the Wuhan University MODIS satellite data ground receiving station, this paper firstly analyze the characteristics of MODIS data and WCS, according to OGC WCS specification, fulfill the design and implement of a MODIS data WCS Server. This paper expatiated the design thoughts, the key technologies and implementation results.

:Multimedia INfOrmation Systems (minos) manage largely unformatted data such as text, image, voice, attributes, and programs. This paper presents the motivation, the hardware tools, the important issues, and the problems involved in the design and implementation of a multimedia object server testbed. The testbed will allow us to study the impact of various design decisions and algorithms on system performance, the most successful of which will be integrated in the final implementation of distributed minos. The distributed architecture proposed is based on the client server model, where an optical disk-based subsystem serves as the archival component and where the presentation manager of the client subsystem includes handling of the internal structure, external logical organization, and browsing through multimedia objects.

Does probability weighting matter in probability elicitation?

In this paper, we explore data replication protocols that provide both fault tolerance and good performance without compromising consistency. We do this by combining transactional concurrency control with group communication primitives. In our approach, transactions are executed at only one site so that not all nodes incur in the overhead of producing results. To further reduce latency, we use an optimistic multicast technique that overlaps transaction execution with total order message delivery. The protocols we present in the paper provide correct executions while minimizing overhead and providing higher scalability.