A queueing network model for a distributed database testbed system

A queuing network model for analyzing the performance of a distributed database testbed system with a transaction workload is developed. The model includes the effects of the concurrency control protocol (two-phase locking with distributed deadlock detection), the transaction recovery protocol (write-ahead logging of before-images), and the commit protocol (centralized two-phase commit) used in the testbed system. The queuing model differs from previous analytical models in three major aspects. First, it is a model for a distributed transaction processing system. Second, it is more general and integrated than previous analytical models. Finally, it reflects a functioning distributed database testbed system and is validated against performance measurements     

A flexible physical layer and fronthaul research testbed for C-RAN

Mobile networks are subject to an explosive increase in data traffic, in a context of continuous mobility and more stringent levels of QoS, which imposes demanding requirements to telecommunication networks. To cope with this trend, a novel paradigm of radio access networks, known as C-RAN, is being developed, where the physical layer processing is also shifted from the edges of the network to a centralized location. C-RAN provides important benefits and will be one of the cornerstones of 5G communication systems. However, some architectural and implementation tradeoffs need to be further evaluated. Moreover, the modularity and extensibility of research platforms supporting C-RAN is still very restrictive. This paper presents a laboratorial platform aimed for the development and trial of C-RAN compliant features. The proposed testbed is very modular and flexible and it is intended to provide a cost-effective emulation and physical layer implementation platform for the main C-RAN modules, namely the BBU, the fronthaul and the RRHs. Based on open FPGA platforms, it features a high level of flexibility in terms of configurations, waveforms and interfaces, and includes all the components required to build an open and complete C-RAN compliant base station. It is mainly used for the experimentation and evaluation of next generation wireless communication systems, including new fronthaul protocols and interfaces as well as 5G waveforms. It integrates a 25  km optical fronthaul, a software defined multi-mode and multi-band RF front-end and a digital radio compression algorithm associated with the optical fronthaul. The inclusion of low-latency (de)compression algorithms was of paramount importance in order to achieve a 50% reduction in terms of fronthaul bandwidth.     

A full-screen facility for defining relational andentity-relationship database schemas

An easy-to-use, interactive facility for defining schemas for a mainframe database system has been developed that is more convenient than a linear language. The facility called Dbdefs, has several features that make it easy to use. It provides similar interfaces for defining schemas for two data models, relational and entity-relationship. An overview of Dbdefs is followed by discussion of the relational and entity-relationship interfaces     

A large-scale image database for benchmarking mobile camera quality and NR-IQA algorithms

Camera-oriented quality assessment (CQA) differs from traditional image quality assessment (IQA) in that “distorted” images are straight out of real devices instead of various types and levels of artificial operations. However, despite its value for both customers and manufacturers, academic and industrial fields, there are few CQA databases created years ago. To reflect recent mobile imaging advancements, we present a new massive Phone Camera Benchmarking database (PCB2021) in this paper. In PCB2021, 40 modern phone units featuring photography are simultaneously compared in 182 scenes for a total of 7280 images, which can be classified into six categories (sub-datasets) based on different focal lengths and user cases: main camera (107), ultra-wide (20), 2$\times$, 3$\times$, 5$\times$ zoom lenses (26, 8, 10) and night-mode (11). The shooting process begins from 7:00 am to 11:00 pm and lasts more than a month. In the subjective study, to overcome the high-resolution-induced overall quality evaluation difficulty, five image attributes: exposure/contrast, color, sharpness, graininess, artifacts are assessed separately on each dataset. To reduce ranking complexity for large-scale cameras, a dynamic anchor ruler method is proposed to obtain quality orders efficiently. With the constructed PCB2021, we further evaluate 15 mainstream no-reference (NR) IQA algorithms. The finding is that for zoomed images, sharpness metrics can achieve Spearman correlation coefficients above 0.8, while for the subtle main camera and night-mode images, performances of all fifteen algorithms drop down quickly, i.e. 0.1-0.2 for the former and $\sim$0.5 for the latter. The entire database, expert rankings and algorithm performance reports will be freely available on request.     

Video-graphic query facility for database retrieval

The goal of this project was to develop a prototype to demonstrate the use of video and graphic techniques applied to the human-machine interface for data retrieval from a typical computerized database. Data is presented to a user via video and graphic means; queries are formulated in one of several graphic formats; control operations are handled through joystick, touch panel, or single-keystroke maneuvers. To accomplish this, we made use of videodisc, interactive computer graphics, and relational database technologies. Still pictures, video segments, and pictures of text are used as visual cues to a user who indicates interest in a data item in a pointing gesture by touching the panel through which the item may be seen. The user may find the actual data item s/he desires, then pose a query for additional information in one of four graphic query formats. A specially designed database was developed to handle the video and graphic data needed for this user facility.     

A benchmarking service for the manufacturing control research community

This paper presents the development—by the IMS Network of Excellence (cf. http://www. ims-noe.org)—of a web-based benchmarking service for manufacturing control systems. The paper first discusses the rationale behind this development. Next, the architecture and usage of the benchmarking service is presented and illustrated. Finally, the paper addresses the current status of the benchmarking service.     

The RAMI On-line Model Checker (ROMC): A web-based benchmarking facility for canopy reflectance models

The exploitation of global Earth Observation data hinges increasingly on physically-based radiative transfer (RT) models. These models simulate the interactions of solar radiation within a given medium (e.g., clouds, plant canopies) and are used to generate look-up-tables that are embedded into quantitative retrieval algorithms, such as those delivering the operational surface products for MODIS, MISR and MERIS. An assessment of the quality of canopy RT models thus appears essential if accurate and reliable information is to be derived from them. Until recently such an undertaking was a time consuming and labour intensive process that was made even more challenging by the general lack of absolute reference standards. Several years of benchmarking activities in the frame of the RAdiation transfer Model Intercomparison (RAMI) exercise have now led to the development of the RAMI On-line Model Checker (ROMC). The ROMC is a web-based tool allowing model developers and users to autonomously assess the performance of canopy RT models (http://romc.jrc.ec.europa.eu/). Access to the ROMC is free and enables users to obtain both statistical and graphical indications as to the performance of their canopy RT model. In addition to providing an overall indication of the skill of a given model to correctly match the reference data, the ROMC allows also for interactive comparison/evaluations of different model versions/submissions of a given user. All ROMC graphs can be downloaded in PostScript format and come with a reference number for easy usage in presentations and publications. It is hoped that the ROMC will prove useful for the RT modeling community as a whole, not only by providing a convenient means to evaluate models outside the triennial phases of RAMI but also to attract participation in future RAMI activities.     

Semantic BMS: Allowing usage of building automation data in facility benchmarking

Facility benchmarking and evaluation of facility performance are the crucial tasks in reaching efficient, economical and sustainable facility operation. Modern buildings are equipped with building automation systems (BAS) that contain vast numbers of various sensors that can be utilised in performance assessment. However, such systems lack convenient tools for data inspection, which limits their use in building performance and efficiency analysis and benchmarking especially on large sites. The paper presents a middleware layer designed to enrich BAS data with additional semantic information. As a semantic model, an adaptation of the Semantic Sensor Network (SSN) ontology for the field of building operation analysis is used. The middleware provides convenient interfaces for querying the model. The proposed system provides the facility managers with a convenient way to use the BAS data for benchmarking and decision support.     

Spatio-temporal composition of video objects: representation andquerying in video database systems

A key characteristic of video data is the associated spatial and temporal semantics. It is important that a video model models the characteristics of objects and their relationships in time and space. J.F. Allen's (1983) 13 temporal relationships are often used in formulating queries that contain the temporal relationships among video frames. For the spatial relationships, most of the approaches are based on projecting objects on a two or three-dimensional coordinate system. However, very few attempts have been made formally to represent the spatio-temporal relationships of objects contained in the video data and to formulate queries with spatio-temporal constraints. The purpose of the work is to design a model representation for the specification of the spatio-temporal relationships among objects in video sequences. The model describes the spatial relationships among objects for each frame in a given video scene and the temporal relationships (for this frame) of the temporal intervals measuring the duration of these spatial relationships. It also models the temporal composition of an object, which reflects the evolution of object's spatial relationships over the subsequent frames in the video scene and in the entire video sequence. Our model representation also provides an effective and expressive way for the complete and precise specification of distances among objects in digital video. This model is a basis for the annotation of raw video     

DipGame: A challenging negotiation testbed

There is a chronic lack of shared application domains to test advanced research models and agent negotiation architectures in Multiagent Systems. In this paper we introduce a friendly testbed for that purpose. The testbed is based on The Diplomacy Game where negotiation and the relationships between players play an essential role. The testbed profits from the existence of a large community of human players that know the game and can easily provide data for experiments. We explain the infrastructure in the paper and make it freely available to the AI community.     

Com-WSN：一种组件化的无线传感器网络测试平台

随着对无线传感器网络研究的不断深入,人们越来越重视利用真实传感器节点进行网络测试。而在真实测试床上实现和测试新的协议需要大量的编码工作。为了能够降低测试编码的复杂度,提出了基于组件的无线传感器网络测试平台Com-WSN。Com-WSN充分考虑了系统资源的合理分配和协议功能的组件化,保证了平台的易用性和扩展性。通过在MICAz平台上的测试,表明Com-WSN能够有效减少编码工作量,提高测试效率,具有很好的易维护性和可扩展性。     

Design and implementation of the OFELIA FP7 facility: The European OpenFlow testbed

The growth of the Internet in terms of number of devices, the number of networks associated to each device and the mobility of devices and users makes the operation and management of the Internet network infrastructure a very complex challenge. In order to address this challenge, innovative solutions and ideas must be tested and evaluated in real network environments and not only based on simulations or laboratory setups.OFELIA is an European FP7 project and its main objective is to address the aforementioned challenge by building and operating a multi-layer, multi-technology and geographically distributed Future Internet testbed facility, where the network itself is precisely controlled and programmed by the experimenter using the emerging OpenFlow technology. This paper reports on the work done during the first half of the project, the lessons learned as well as the key advantages of the OFELIA facility for developing and testing new networking ideas.An overview on the challenges that have been faced on the design and implementation of the testbed facility is described, including the OFELIA Control Framework testbed management software. In addition, early operational experience of the facility since it was opened to the general public, providing five different testbeds or islands, is described.     

A database for handwritten text recognition research

An image database for handwritten text recognition research is described. Digital images of approximately 5000 city names, 5000 state names, 10000 ZIP Codes, and 50000 alphanumeric characters are included. Each image was scanned from mail in a working post office at 300 pixels/in in 8-bit gray scale on a high-quality flat bed digitizer. The data were unconstrained for the writer, style, and method of preparation. These characteristics help overcome the limitations of earlier databases that contained only isolated characters or were prepared in a laboratory setting under prescribed circumstances. Also, the database is divided into explicit training and testing sets to facilitate the sharing of results among researchers as well as performance comparisons     

A video database of moving faces and people

We describe a database of static images and video clips of human faces and people that is useful for testing algorithms for face and person recognition, head/eye tracking, and computer graphics modeling of natural human motions. For each person there are nine static "facial mug shots" and a series of video streams. The videos include a "moving facial mug shot," a facial speech clip, one or more dynamic facial expression clips, two gait videos, and a conversation video taken at a moderate distance from the camera. Complete data sets are available for 284 subjects and duplicate data sets, taken subsequent to the original set, are available for 229 subjects.     

An open virtual testbed for industrial control system security research

Industrial control system security has been a topic of scrutiny and research for several years, and many security issues are well known. However, research efforts are impeded by a lack of an open virtual industrial control system testbed for security research. This paper describes a virtual testbed framework using Python to create discrete testbed components including virtual devices and process simulators. The virtual testbed is designed such that the testbeds are inter-operable with real industrial control system devices and such that the virtual testbeds can provide comparable industrial control system network behavior to a laboratory testbed. Two virtual testbeds modeled upon actual laboratory testbeds have been developed and have been shown to be inter-operable with real industrial control system equipment and vulnerable to attacks in the same manner as a real system. Additionally, these testbeds have been quantitatively shown to produce traffic close to laboratory systems.     

Push: An experimental facility for implementing distributed database services in operating systems

Distributed database systems need speciaal operating system support. Support routines can be implemented inside the kernel or at the user level. Kernel-level functions, while efficient, are hard to implement. User-level implementations are easier but suffer from poor performance and lack of security. This article proposes a new approach to supplement or modify kernel facilities for database transaction processing. Our experimental facility, called Push, is based on an extension language interpreted within the kernel. Our implementation provides the efficiency of kernel-resident code as well as the simplicity and safety of user-level programming. This facility enables experimentation that would be difficult and time-consuming in current environments. The overhead of the Push implementation can be factored out to give a good estimate of the performance of a native kernel implementation. We have used Push to implement several kernel-resident services. In the case of multi-RPC and commit protocols, Push implementations significantly improve performance and scalability over user-level implementations. The experiments show the benefits of Push both as an operational tool for improving transaction processing performance and as an experimental tool for investigating the benefits of operating systems extension without costly implementation.This research is supported by NASA and AIRMICS under grant number NAG-1-676, NSF grant IRI-8821398, and AT&T.     

硬盘录像中的多媒体数据库

介绍了硬盘录像的系统结构、多媒体数据库的主要功能,着重讨论了系统规范、数据入库、OLE机制、查询、数据库安全等几个关键问题。     

Finite element design of manipulator-coupled spacecraft for a research testbed

This paper describes the design and analysis of a research testbed developed to study the control of manipulator-coupled spacecraft with independent attitude control systems. This scenario could present itself in the assembly of Space Station Freedom (SSF). SSF assembly calls for a rendezvous of the Space Shuttle (SS) with SSF. Part of the assembly process requires that both spacecraft be coupled via the Space Shuttle Remote Manipulator System. An additional criterion that poses increased complexity is that the Space Shuttle controls and Space Station controls can not communicate. The technical issue involved is unwanted vibrations of the coupled-configuration that occur retraction and the complications due to non-interacting control systems. To understand these vibrations and possible complications, a research testbed has been built at the Marshall Space Flight Center in Huntsville, AL.To build the testbed, the manipulator links joints, and vehicles that represent the Space Shuttle and Space Station had to be designed. Pre-design simulation studies using ANSYS [1] (a Finite Element Computer Code) is used to size and design the manipulator links for the experimental facility. The ANSYS results were verified by the development of the Lagrangian Equations of motion. The Harmonic drives used as joints for the two link, three joint manipulator have been dissected into free body diagrams to ensure proper load paths in the ANSYS models. Accurate simulation of manipulator-coupled spacecraft is an important technology for NASA to understand. This paper outlines the methodology behind the preliminary design of a research testbed developed to help NASA gain knowledge in this area.