User Operation Research Articles

Vacuum system design, construction, and operation for the Cornell High Energy Synchrotron Source upgrade

During the summer and fall 2018, the Cornell High Energy Synchrotron Source (CHESS), underwent an upgrade that recast the facility as primarily a low emittance X-ray source. The upgrade replaced one sixth of the Cornell Electron Storage Ring (CESR) with six double-bend achromats, featuring four novel CHESS Compact Undulator (CCU) insertion devices, and switched CESR to single particle beam operation. At the time of this writing, the upgraded storage ring has achieved the CHESS-U design goal of operating with 200 mA of positron current at 6.0 GeV beam energy. Seven out of eleven CHESS-U beamlines are currently in X-ray user operation. The construction and the commissioning of the new section of the CESR accelerator required novel solutions to design, fabrication, and vacuum system operations. Significant design considerations and efforts were made to minimize X-ray ‘dark-time’, returning to operation less than 1 year. This paper describes the important milestones of the process, the solutions implemented, and the present status of CHESS-U.

Statistical models of network traffic

The article considers the issues of statistical modeling of traffic in telecommunication networks with packet switching. The simulation results are used in the development of network technical condition management systems, in particular, diagnostics, troubleshooting and network configuration management. The peculiarities of congestion control of separate network segments are emphasized. With improper analysis the overload condition can be mistaken for equipment failure. Therefore, control and elimination of congestion is a statistical task. The concept of end-to-end network diagnostics is considered. This concept provides for effective assessment of the quality of functioning of all network components taking into account their interrelationships. The main issues are the interaction of equipment, inefficient configuration, improper network organization and user operation. Methods of traffic statistical control characteristics based on perforated and marker bucket algorithms are analyzed. A feature of these algorithms is the formation of a strict output stream at a rate that does not depend on the non-uniformity of the input stream. The possibility of improving the token bucket algorithm by adapting to changes in the statistical characteristics of traffic is shown. To solve this problem, statistical mathematical models of network traffic are built. Data traffic circulating in telecommunication networks by packet switching has self-similar (fractal) properties. The self-similar process retains its properties when considered at different time scales (invariance to scale changes). The degree of statistical stability of the process with multiple scaling is determined by the Hirst parameter (the self-similarity parameter). Graphs of statistical characteristics of low-speed and high-speed data traffic are obtained. Their comparative analysis is carried out.

SSN_SEM: Design and application of a fusion ontology in the field of medical equipment

Abstract The importance of standardized operation of medical equipment is self-evident. An effective method is to construct the medical equipment domain ontology as the background knowledge base, and make judgments on the legality of the user’s operation sequence based on the ontology, and guide the user to legally operate the equipment. After analysis, medical device data mainly comes from internal sensors. If we want to build an ontology background knowledge base, we can combine data with user operations, map the ontology to events, and build a directed graph model through events to form the final ontology. In this paper, we take the atomized particle preparation device in the field of medical equipment as an example, and selects and constructs the ontology by analyzing the internal structure and use process of the device.The application-level ontology selects the SSN ontology in the sensor field, and the upper ontology selects the general event ontology SEM. Combining the above two ontology and the characteristics of the medical device field, the ontology SSN_SEM is constructed, and the actual data of the device is semantically annotated through the SSN_SEM ontology, which verifies the validity of the ontology.

Energy detectors performance evaluation for interweave cognitive radio network scenario in 5G

With the recent advances in resource allocation methods for 5G heterogeneous networks and dynamic spectrum access, the convergence between them becomes a more prevalent topic in scientific research. By implementing cognitive functionalities in the 5G network’s nodes, its efficiency can be improved and, in addition, the integration with existing wireless standards will be smoother. To enable this, the intelligent sensors are required to achieve rigid detection accuracy. Thus, the purpose of this paper is to examine the ability of popular energy detection spectrum sensing techniques to identify the primary user’s signal in an interweave (autonomous operation of the secondary users) 5G deployment scenario. This evaluation is performed through comprehensive simulations for differing number of primary and secondary users, and for different data stream types transmitted by the primary base station.

New open computational resource for plasma processes modelling

The paper describes a new open access computing resource nfusion.cs.msu.ru. The resource includes modules for calculating equilibrium, vertical stability, plasma evolution, simulation systems for magnetic diagnostics, as well as a new algorithm for constructing three-dimensional tetrahedral meshes in areas of complex structure. The modules are integrated into a unified software environment designed for numerical support of experiments on tokamak installations. The possibility of accessing the calculation modules on the server via the Internet, data exchange and the issuance of calculation results in the form of files, figures, and tables has been implemented. The resource supports the simultaneous operation of several users and has an information support system in Russian and English.

A group decision-making model for important power user risks based on cloud model and set pair analysis: a case study in China

The safe and stable operation of important power users plays an important role in the harmonious development of society and economy. Different from previous studies which mostly based on reliability model, a group decision-making model based on cloud model and connection number is proposed in this paper. First, an assessment index system is established including operation safety risk, cooperation credit risk, power regulation risk and operating capacity risk. Then, with the advantage in dealing with qualitative language, cloud model is employed to convert the qualitative concepts into quantitative values, which reduce the fuzziness and randomness. Next, in order to integrate the information among different index, the geometric operator of binary connection number is defined. Finally, the comparison method of connection numbers is put forward to rank the results. The example and sensibility analysis verify the effectiveness and applicability of the model in this paper.

Retracted] Research on Recognition Method of Basketball Goals Based on Image Analysis of Computer Vision

Moving target detection is involved in many engineering applications, but basketball has some difficulties because of the time‐varying speed and uncertain path. The purpose of this paper is to use computer vision image analysis to identify the path and speed of a basketball goal, so as to meet the needs of recognition and achieve trajectory prediction. This research mainly discusses the basketball goal recognition method based on computer vision. In the research process, Kalman filter is used to improve the KCF tracking algorithm to track the basketball path. The algorithm of this research is based on MATLAB, so it can avoid the mixed programming of MATLAB and other languages and reduce the difficulty of interface design software. In the aspect of data acquisition, the extended EPROM is used to store user programs, and parallel interface chips (such as 8255A) can be configured in the system to output switch control signals and display and print operations. The automatic basketball bowling counter based on 8031 microprocessor is used as the host computer. After the level conversion by MAX232, it is connected with the RS232C serial port of PC, and the collected data is sent to the workstation recording the results. In order to consider the convenience of user operation, the GUI design of MATLAB is used to facilitate the exchange of information between users and computers so that users can see the competition results intuitively. The processing frame rate of the tested video image can reach 60 frames/second, more than 25 frames/second, which meet the real‐time requirements of the system. The results show that the basketball goal recognition method used in this study has strong anti‐interference ability and stable performance.

Overview of SwissFEL dual-photocathode laser capabilities and perspectives for exotic FEL modes

Abstract SwissFEL is a compact, high-brilliance, soft and hard X-ray free electron laser (FEL) facility that started user operation in 2019. The facility is composed of two parallel beam lines seeded by a common linear accelerator (LINAC), and a two-bunch photo-injector. For the injector, an innovative dual-photocathode laser scheme has been developed based on state-of-the-art ytterbium femtosecond laser systems. In this paper, we describe the performance of the SwissFEL photocathode drive lasers (PCDLs), the pulse-shaping capabilities as well as the versatility of the systems, which allow many different modes of operation of SwissFEL. The full control over the SwissFEL electron bunch properties via the unique architecture of the PCDLs will enable in the future the advent of more-advanced FEL modes; these modes include, but are not restricted to, the generation of single or trains of sub-femtosecond FEL pulses, multi-color FEL and finally, the generation of fully coherent X-ray pulses via laser-based seeding.

Demand Responsive Market Decision-Makings and Electricity Pricing Scheme Design in Low-Carbon Energy System Environment

The two-way interaction between smart grid and customers will continuously play an important role in enhancing the overall efficiency of the green and low-carbon electric power industry and properly accommodating intermittent renewable energy resources. Thus far, the existing electricity pricing mechanisms hardly match the technical properties of smart grid; neither can they facilitate increasing end users participating in the electricity market. In this paper, several relevant models and novel methods are proposed for pricing scheme design as well as to achieve optimal decision-makings for market participants, in which the mechanisms behind are compatible with demand response operation of end users in the smart grid. The electric vehicles and prosumers are jointly considered by complying with the technical constraints and intrinsic economic interests. Based on the demand response of controllable loads, the real-time pricing, rewarding pricing and insurance pricing methods are proposed for the retailers and their bidding decisions for the wholesale market are also presented to increase the penetration level of renewable energy. The proposed demand response oriented electricity pricing scheme can provide some useful operational references on the cooperative operation of controllable loads and renewable energy through the feasible retail and wholesale market pricing methods, and thereby enhancing the development of the low-carbon energy system.

A 3D spatiotemporal morphological database for urban green infrastructure and its applications

The morphology of urban green infrastructure (UGI) will affect the quality of urban environment and the way people perceive. The three-dimensional morphological features of UGI have been proven to be the key factors to effect urban ecological environment, which have rarely been incorporated into the UGI morphology in the previous researches. In this paper, a systematic approach to develop a 3D spatiotemporal morphological database for UGI is proposed. The database is built on a complete set of information describing the form of UGI in the plane, the vertical direction and the temporal changes. In addition, three categories of morphological parameters of UGI are calculated and integrated in the database. User operation and visualization and morphological parameter operation is achievable in the database. The database can be further integrated with simulation programs and analytical models so that it can be used in the design and research of various urban sustainable subjects. In a case study, we further create a complete 3D spatiotemporal morphological database of UGI for an urban district of 4km² in Nanjing, China.

Hands-Free User Interface for VR Headsets Based on In Situ Facial Gesture Sensing.

The typical configuration of virtual reality (VR) devices consists of a head-mounted display (HMD) and handheld controllers. As such, these units have limited utility in tasks that require hand-free operation, such as in surgical operations or assembly works in cyberspace. We propose a user interface for a VR headset based on a wearer’s facial gestures for hands-free interaction, similar to a touch interface. By sensing and recognizing the expressions associated with the in situ intentional movements of a user’s facial muscles, we define a set of commands that combine predefined facial gestures with head movements. This is achieved by utilizing six pairs of infrared (IR) photocouplers positioned at the foam interface of an HMD. We demonstrate the usability and report on the user experience as well as the performance of the proposed command set using an experimental VR game without any additional controllers. We obtained more than 99% of recognition accuracy for each facial gesture throughout the three steps of experimental tests. The proposed input interface is a cost-effective and efficient solution that facilitates hands-free user operation of a VR headset using built-in infrared photocouplers positioned in the foam interface. The proposed system recognizes facial gestures and incorporates a hands-free user interface to HMD, which is similar to the touch-screen experience of a smartphone.

Heavy ion beam physics at Facility for Rare Isotope Beams

The Facility for Rare Isotope Beams (FRIB) will be the world's premier rare-isotope beam facility. Experiments with the majority (∼80%) of the isotope predicted to exist will become available. The FRIB facility is based on a superconducting (SC) heavy ion linac with output energy above 200 MeV/u for any ions at beam power of 400 kW. FRIB includes a target facility for in-flight production of rare isotopes. A three-stage fragment separator will be used to prepare fast rare isotope beams with high-purity for nuclear physics experiments. The installation work of the accelerator and experimental systems is approaching completion and multi-stage beam commissioning activities started in summer 2017 with expected project completion in early 2022. The commencement of operation for users' experiments is planned immediately following the project completion.

Wireless‐powered CR‐IoT with ambient backscattering: a new transmission mode

In this study, a new hybrid secondary transmitter (ST) mode is proposed for cognitive radio Internet of Things (CR-IoT) networks with energy harvesting (EH) and ambient backscatter (AmBack) communication capabilities. The authors firstly describe the proposed hybrid mode with wireless-powered ST. The ST, consisting of EH, Amback, and conventional active transmission modules, adapts itself under different primary user operation states, i.e. active or idle. The overall throughput of the secondary system is formulated and the system settings for achieving optimal performance are derived and validated through numerical simulations.

An Efficient Identity Based Encryption in Cloud Computing with Outsourced Revocation

Identity-Based Encryption (IBE) which simplifies the public key and certificate management at Public Key Infrastructure (PKI) is an important alternative to public key encryption. However, one of the main efficiency drawbacks of IBE is the overhead computation at Private Key Generator (PKG) during user revocation. Efficient revocation has been well studied in traditional PKI setting, but the cumbersome management of certificates is precisely the burden that IBE strives to alleviate [2]. It aiming at tackling the critical issue of identity revocation, we introduce outsourcing computation into IBE for the first time and propose a revocable IBE scheme in the server-aided setting. Our scheme offloads most of the key generation related operations during key-issuing and key-update processes to a Key Update Cloud Service Provider, leaving only a constant number of simple operations for PKG and users to perform locally [3]. This goal is achieved by utilizing a novel collusion-resistant technique: we employ a hybrid private key for each user, in which an AND gate is involved to connect and bound the identity component and the time component [4]. Furthermore, we propose another construction which is provable secure under the recently formulized Refereed Delegation of Computation model. Finally, we provide extensive experimental results to demonstrate the efficiency of our proposed construction. In public key encryption every user must have a pair of keys, public key and private key, for encrypting and decrypting messages. An Identity-based encryption (IBE) eliminates the need for a Public Key Infrastructure (PKI). IBE uses the human intelligible identities (e.g., unique name, email address, IP address, etc) as public keys [5]. The sender using IBE encrypts message with the receivers’ identity rather than looking for receivers’ public key and corresponding certificate. Accordingly, receiver decrypts ciphertext using private key associated with the corresponding identity [6]. The private keys of users are obtained from a trusted third party called as Private Key Generator (PKG). The motivation of this paper is to study and review an efficient and secure Identity based encryption scheme with outsourced revocation for cloud computing [7].

Quantum Sealed-Bid Auction Protocol Based on Semi-honest Model

In view of the possible disclosure of personal information in the quantum auction protocol, by using the correlation between entangled particles and quantum teleportation, we propose a secure quantum sealed-bid auction (QSBA) protocol based on semi-honest model. In this protocol, by introducing a trusted third party Trent, we separate the registration operation of users from the business function of auction center. Bidders and the auction center can realize quantum identity authentication without information disclosure, so as to reduce the risk of the auction center disclosing the personal information of bidders. With the help of Trent, using the quantum sequences to be the information carrier of bidding, the auction center and bidders can conduct quantum teleportation to obtain each bidding price. When the auction center publishes the bid price and serial number, the registration center also publishes the corresponding winning bidder. Through security analysis, our protocol can guarantee the anonymity of bidders and the integrity of bidding information.

Design and Development of GPS Navigation and Positioning System based on AutoCAD Platform

According to the design of the software system, the positioning chip configured in the positioning terminal can be GPS, or a hybrid positioning system, plus optional position differential function, which ensures the positioning accuracy and maintains data security at the same time. Software system using cloud computing technology and C/S, B/S hybrid architecture for development, the system can be deployed on an ordinary PC to achieve greater capacity and higher performance, companies or individuals only need to be equipped with positioning terminals can directly use the system, but also according to their own needs to further modify the system realized in this paper customized. This greatly reduces the development and maintenance costs of the system and is beneficial to the promotion and use of the system. The satellite positioning information is received from the positioning terminal, decoded according to the present decoding algorithm, and sent to the database server for storage; remote control commands are received from the terminal administrator, processed, and sent to the positioning terminal. Web server, which provides access service to the user's operation platform. Service server, which provides service support for business logic to the user operation platform. The user operation platform is divided into the ordinary user operation platform and the terminal administrator operation platform.

User-centered system design for assisted navigation of visually impaired individuals in outdoor cultural environments

The marginalization of people with disabilities, such as visually impaired individuals (VIIs), has driven scientists to take advantage of the fast growth of smart technologies and develop smart assistive systems (SASs) to bring VIIs back to social life, education and even to culture. Our research focuses on developing a human–computer interactive system that will guide VIIs in outdoor cultural environments by offering universal access to cultural information, social networking and safe navigation among other services. The VI users interact with computer-based SAS to control the system during its operation, while having access to remote connection with non-VIIs for external guidance and company. The development of such a system needs a user-centered design (UCD) that incorporates the elicitation of the necessary requirements for a satisfying operation for the VI users. In this paper, we present a novel SAS system for VIIs and its design considerations, which follow a UCD approach to determine a set of operational, functional, ergonomic, environmental and optional requirements of the system. Both VIIs and non-VIIs took part in a series of interviews and questionnaires, from which data were analyzed to form the requirements of the system for both the on-site and remote use. The final requirements are tested by trials and their evaluation and results are presented. The experimental investigations gave significant feedback for the development of the system, throughout the design process. The most important contribution of this study is the derivation of requirements applicable not only to the specific system under investigation, but also to other relevant SASs for VIIs.

Task-based obstacle avoidance for uncertain targets based on semantic object matrix

Service robots meet numerous tasks-level commands with uncertain relationship between targets and obstacles, which introduces plenty of programming work involved with obstacle avoidance in robots’ operations for non-expert users. Hence an obstacle avoidance algorithm based on task semantic object matrix(SOM) was introduced to tell targets from obstacles in this paper. With this strategy, petri net was applied to decompose the robots’ complex operation tasks into sequential subtasks, which can be practical for finite state machine. And the SOM related to sequential subtasks was generated synchronously. Based on the SOM, the point cloud segmentation, collision geometry modeling and the transformation between targets and obstacles can be conducted for robots’ operations. Experimental results indicate that the SOM can be updated within 0.25s. And the experiments demonstrated that this algorithm is feasible to help non-expert users conduct robots’ task-based operations.

Test Case Generation Method Based on User Operation

After the software is published, its users are mainly operators. Although they can find problems with the software, they cannot identify and reproduce software failures. When the software fails, there must be a lot of information related to the failure in the running data of the software to be tested. Therefore, on the basis of obtaining the running data of the software under test, a test case generation method based on user operation is proposed. Based on the generation of software failure, the operation related to the failure is filtered out from the user operation. By taking these operations as the values of the system parameters to be tested, test cases that will inevitably cause software failure are obtained. Finally, the validity of the method is verified by an example, and the test cases obtained are specific to the faults of the software.

Dynamic test method for full body harnesses exploited in cold climates

In this paper, a method of testing the dynamic strength of full body harnesses is proposed. The possibility of conducting the method in laboratory conditions is determined by testing the method while maintaining the specified conditions of low temperatures. The main attention is paid to the effect of the set temperature on the full body harnesses, when dynamic shock loads occur in user operation mode. The advantage of the developed method of dynamic testing of full body harnesses is the simplicity in bringing the test sample to the climatic parameters of operation by pre-conditioning. This makes it possible to implement dynamic testing under specified climatic conditions within mass laboratories in the chain of conformity confirmation. Pre-conditioning allows you to conduct research on the influence of climate factors on various characteristics of safety harnesses. The interaction of the binding elements with each other, previously reduced to the specified temperature parameters, is also studied. It is necessary to pay special attention to the resulting impact loads during dynamic tests, and their relationship when conditioning products at different temperature.