Ssdev-Ecat: A Configurable Motion Control Server for Mars 2020 Hardware Testbeds

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.

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.

With the development of embedded technology and Internet, it would become the future trend to implement the management of UPS on network. A monitor and control model of UPS was presented in this paper according to the standard of Megatec communication protocol based on the design and implementation of Web Server, embedded file system and the architecture software and hardware of this system. So the administrator could monitor and control the UPS anywhere with the limit to the distance and the time.

IP Multimedia Subsystem (IMS) offers a plethora of functionalities in 4G/LTE networks. One such functionality is the video conference where three or more User Equipments (UEs) communicate with each other using VoLTE. This research paper presents optimizations in the design and implementation of an IMS video conference server for reducing the video display delay and improving the performance thereof. Both application as well as network level parameters are found to impact the video display delay at the UE, hence performance improvement of both are considered in this paper. Optimization techniques adopted in this implementation resulted in enhanced performance of video conference calls over the LTE network.

In many distributed systems concurrent access is required to a shared object, where abstract object servers may incorporate type-specific properties to define consistency requirements. Each operation and its outcome is treated as an event, and conflicts may occur between different event types. Hence concurrency control and synchronization are required at the granularity of conflicting event types. With such a fine granularity of locking, the occurrence of conflicts is likely to be lower than with whole-object locking, so optimistic techniques become more attractive. This work describes the design, implementation, and performance of servers for a shared atomic object, a semiqueue, where each server employs either pessimistic or optimistic locking techniques on each conflicting event type. We compare the performance of a purely optimistic server, a purely pessimistic server, and a hybrid server which treats certain event types optimistically and others pessimistically, to demonstrate the most appropriate environment for using pessimistic, optimistic, or hybrid control. We show that the advantages of low overhead on optimistic locking at low conflict levels is offset at higher conflict levels by the wasted work done by aborted transactions. To achieve optimum performance over the whole range of conflict levels, an adaptable server is required, whereby the treatment of conflicting event types can be changed dynamically between optimistic and pessimistic, according to various criteria depending on the expected frequency of conflict. We describe our implementations of adaptable servers which may allocate concurrency control strategy on the basis of state information, the history of conflicts encountered, or by using preset transaction priorities. We show that the adaptable servers perform almost as well as the best of the purely optimistic, pessimistic, or hybrid servers under the whole range of conflict levels, showing the versatility and efficiency of the dynamic servers. Finally we outline a general design methodology for implementing adaptable concurrency control in servers for atomic objects, illustrated using an atomic shared B-tree.

We describe the design and implementation of the Exedra continuous media server, and experimentally evaluate alternative resource management policies using a prototype system that we built. Exedra has been designed to provide scalable and efficient support for variable bit-rate media streams whose compression efficiency leads to reduced storage space and bandwidth requirements in comparison to constant bit-rate streams of equivalent quality. We examine alternative disk striping policies, and quantify the benefits of innovative techniques for storage space allocation, buffer management, and resource reservation, which we developed to achieve both predictability and high-performance in handling disk and network data transfers of variable size. Additionally, we investigate the differences between diverse data replication schemes over disk arrays, and compare methods for disk access time reservation that enable tolerance of disk failures at minimal cost. Overall, we demonstrate the feasibility of building network media servers that exploit the latest advances in media compression technology towards reducing the cost of wide-scale streaming services for stored data.

This paper presents the design and implementation of Asterisk server, which serves as the local exchange for placing voice and video calls within a private Wi-Fi cloud and legacy networks, that is, with the Public Switch Telephony Network (PSTN). The model is accessible within the area of a university campus and allows only those mobile phones and PCs' to connect to the Asterisk server which are registered with the wireless network. The work proposed in this paper has an added feature for placing the voice and video calls on mobile phones hence increasing the mobility of a user. The model is successful in carrying out voice and video calls on Android supported hand helds connected with the wireless network and PCs connected with both wired LAN and wireless LAN. Further, every user is provided with his own extension number that can be used to connect to the outside world.

Networked Musical Performance (NMP) occurs when a group of musicians, which are located in places that are physically separated, interacting via a network to play music together as if the musicians are located in the same room. NMP system is susceptible to latency. The limit of total latency acceptable in a music performance is 30 milliseconds. The research is conducted to find out how BeatME Server application can receive input from BeatME Client applications over the network and synthesize sound based on the input, with acceptable total latency in a musical performance. BeatME Server application is developed using MIDI command as input, and OSC as the method of client and server communication. Audio synthesis is performed using SoundFont standard. This application is tested on LAN. The work shows that the average latency obtained when the communication conducted via LAN is 3 milliseconds. The biggest factor of the latency is the difference between the time when the audio data was sent by BeatME Server and the time when the sound is generated by the soundcard. Therefore, it is important to select the right audio driver and audio buffer size.