Performance Improvement For Users Research Articles

Effect of Vibrotactile Feedback on the Control of the Interaction Force of a Supernumerary Robotic Arm

Supernumerary robotic limbs are mainly designed to augment the physical capabilities of able-bodied individuals, in a wide range of contexts from body support to surgery. When they are worn as wearable devices, they naturally provide inherent feedback due to the mechanical coupling with the human body. The user can, thus, perceive the interaction with the environment by relying on a combination of visual and inherent feedback. However, these can be inefficient in accomplishing complex tasks, particularly in the case of visual occlusion or variation in the environment stiffness. Here, we investigated whether, in a force-regulation task using a wearable supernumerary robotic arm (SRA), additional vibrotactile feedback can increase the control performance of participants compared to the inherent feedback. Additionally, to make the scenario more realistic, we introduced variations in the SRA’s kinematic posture and in the environment stiffness. Notably, our findings revealed a statistically significant improvement in user performance over all the evaluated metrics while receiving additional vibrotactile feedback. Compared to inherent feedback alone, the additional vibrotactile feedback allowed participants to exert the required force faster (p < 0.01), to maintain it for longer (p < 0.001), and with lower errors (p < 0.001). No discernible effects related to the SRA’s posture or environment stiffness were observed. These results proved the benefits of providing the user with additional vibrotactile feedback to convey the SRA’s force during interaction tasks.

Performance of the NOMA user in FFR Millimeter Wave Networks

ABSTRACT Non-Orthogonal Multiple Access (NOMA) and Fractional Frequency Reuse (FFR) were touted as two key techniques of the millimetre wave cellular system to derive spectrum efficiency and user performance improvement. By combining the NOMA and FFR techniques, this paper proposes a system to improve the performance of the NOMA user that utilises the NOMA-power domain technique to reuse an occupied Resource Block (RB). Besides following the power allocation policy of the NOMA technique, the resource allocation algorithm for the NOMA user is based on the FFR technique. Particularly, if the downlink Signal-to-Interference-plus-Noise ratio (SINR) of the NOMA user is greater than the threshold, it is allocated the Cell-Edge RB with a high interference level. Otherwise, it is served on the Cell-Center RB with a low interference level. The analytical and simulation results state that the proposed system can increase the coverage probability of the NOMA user up to 250%.

Coexisting Passive RIS and Active Relay-Assisted NOMA Systems

A novel coexisting passive reconfigurable intelligent surface (RIS) and active decode-and-forward (DF) relay assisted non-orthogonal multiple access (NOMA) transmission framework is proposed. In particular, two communication protocols are conceived, namely Hybrid NOMA (H-NOMA) and Full NOMA (F-NOMA). Based on the proposed two protocols, both the sum rate maximization and max-min rate fairness problems are formulated for jointly optimizing the power allocation at the access point and relay as well as the passive beamforming design at the RIS. To tackle the non-convex problems, an alternating optimization (AO) based algorithm is first developed, where the transmit power and the RIS phase-shift are alternatingly optimized by leveraging the two-dimensional search and rank-relaxed difference-of-convex (DC) programming, respectively. Then, a two-layer penalty based joint optimization (JO) algorithm is developed to jointly optimize the resource allocation coefficients within each iteration. Finally, numerical results demonstrate that: i) the proposed coexisting RIS and relay assisted transmission framework is capable of achieving a significant user performance improvement than conventional schemes without RIS or relay; ii) compared with the AO algorithm, the JO algorithm requires less execution time at the cost of a slight performance loss; and iii) the H-NOMA and F-NOMA protocols are generally preferable for ensuring user rate fairness and enhancing user sum rate, respectively.

Internet Traffic based Channel Selection in Multi-Radio Multi-Channel Wireless Mesh Networks

Wireless Mesh Networks(WMNs) are the outstanding technology to facilitate wireless broadband Internet access to users. Routers in WMN have multiple radio interfaces to which multiple orthogonal/partially overlapping channels are assigned to improve the capacity of WMN. This paper is focused on channel selection problem in WMN since proper channel selection to radio interfaces of mesh router increases the performance of WMN. To access the Internet through WMN, the users have to associate with one of the mesh routers. Since most of the Internet Servers are still in wired networks, the major dominant traffic of Internet users is in downlink direction i.e. from the gateway of WMN to user. This paper proposes a new method of channel selection to improve the user performance in downlink direction of Internet traffic. The method is scalable and completely distributed solution to the problem of channel selection in WMN. The simulation results indicate the significant improvement in user performance.

Performance of Multi-Cell mmWave NOMA Networks With Base Station Cooperation

Coordinated multipoint transmission is applied to multi-cell millimeter wave (mmWave) non-orthogonal multiple access (NOMA) networks in downlink transmission in this letter. Multiple cooperative base stations (BSs) jointly transmit same signal to a cell-edge user as a far user. And each BS individually serves a near user at the same beamwidth with NOMA. Subsequently, the outage probability, outage sum rate and energy efficiency are derived. Further, simulation results are provided to verify the correctness of analytical derivation and demonstrate the cell-edge user's performance improvement as well as the superiority of BS cooperation in multi-cell mmWave NOMA networks.

When Machine Learning Meets Wireless Cellular Networks: Deployment, Challenges, and Applications

AI powered wireless networks promise to revolutionize the conventional operation and structure of current networks from network design to infrastructure management, cost reduction, and user performance improvement. Empowering future networks with AI functionalities will enable a shift from reactive/incident-driven operations to proactive/ data-driven operations. This article provides an overview on the integration of AI functionalities in 5G and beyond networks. Key factors for successful AI integration such as data, security, and explainable AI are highlighted. We also summarize the various types of network intelligence as well as machine-learning-based air interface in future networks. Use case examples for the application of AI to the wireless domain are then summarized. We highlight applications to the physical layer, mobility management, wireless security, and localization.

Internet Traffic based Channel Selection in Multi-Radio Multi-Channel Wireless Mesh Networks

Wireless Mesh Networks(WMNs) are the outstanding technology to facilitate wireless broadband Internet access to users. Routers in WMN have multiple radio interfaces to which multiple orthogonal/partially overlapping channels are assigned to improve the capacity of WMN. This paper is focused on channel selection problem in WMN since proper channel selection to radio interfaces of mesh router increases the performance of WMN. To access the Internet through WMN, the users have to associate with one of the mesh routers. Since most of the Internet Servers are still in wired networks, the major dominant traffic of Internet users is in downlink direction i.e. from the gateway of WMN to user. This paper proposes a new method of channel selection to improve the user performance in downlink direction of Internet traffic. The method is scalable and completely distributed solution to the problem of channel selection in WMN. The simulation results indicate the significant improvement in user performance.

Improvement of User Performance in Virtual Reality by Boosting Sense of Agency

Virtual reality is a relatively new field of human activity that is seeing a greater influx of users in the recent years thanks to consumer versions of virtual reality head mounted display sets providing the necessary image fidelity for the early adopters. That being said, there are still several obstacles that virtual reality applications have to overcome in order for the user to finally accept it. While physiological complications like simulator sickness are a subject for medical students, the other issue, namely the uncanny valley or the acceptance problem is something purely technical. This paper reviews ways for improving user performance and engagement in virtual reality applications by addressing psychological aspects of the user to virtual environment interaction. The primary aspect is the sense of agency, which has been reviewed in detail and defined as a notion with complex structure. Its connections to sense of embodiment and sense of ownership have been reviewed and ways for their improvement were established. Sense of body ownership was reviewed and was proven as such that has no impact on user productivity. Thus, user avatar can be simplified without hindering the sense of agency. Each aspect or aspect group has been determined to have its ways for degradation and improvement. Additionally, several experiments have shown that user productivity and precision was positively influenced when they were presented with a higher fidelity simulation, resulting in a stronger sense of agency. While designing a better experience is a very application-specific task, creating a set of rules and a framework that enables these applications to follow a set of guidelines without developer effort is a universal notion. Framerate, image fidelity and avatar detail have been the primary target for methods of improvement: maximizing image fidelity while ignoring avatar detail and boosting framerate are all positively influencing the sense of agency and thus productivity. Lack of interruptions in input tracking also greatly improves the sense of agency, and hardware improvements are one of the methods of productivity boosting. To reach the set goals within reasonable hardware constraints however a foveated rendering method was suggested as a tool to optimally enhance the image fidelity based on recent findings about user’s peripheral vision in virtual reality.Ref. 19.

Long-Term Multi-Resource Fairness for Pay-as-you Use Computing Systems

Many current computing systems such as clouds and supercomputers charge users for their resource usages. A user’s demand is often changing over time, indicating that it is difficult to keep the high resource utilization all the time for cost efficiency. Resource sharing is a classical and effective approach for high resource utilization. In view of the heterogeneous resource demands of users’ workloads, multi-resource allocation fairness is a must for resource sharing in such pay-as-you-use computing systems . However, we find that, existing multi-resource fair policies such as Dominant Resource Fairness (DRF), implemented in currently popular resource management systems such as Apache YARN [4] and Mesos [23] , are not suitable for the pay-as-you-use computing systems. We show that this is because of their memoryless characteristic that can cause the following problems in the pay-as-you-use computing systems: 1). users can get resource benefits by cheating; 2). users might not be able to get the total amount of resources that they are entitled to in terms of their resource contributions. In this paper, we propose a new policy called H-MRF, which generalizes DRF and Asset Fairness with the long-term notion. We show that it can address these problems and is suitable for pay-as-you-use computing systems. We have implemented it into YARN by developing a prototype called MRYARN . Finally, we evaluate H-MRF using both testbed and simulated experiments. The experimental results show that there are about $1.1\sim 1.5$ sharing benefit degrees and $1.2\times \sim 1.8\times$ performance improvement for users with H-MRF, better than existing fair schedulers.

Quantitative modeling of user performance in multitasking environments

Multitasking is one of the most important skills required for human operators to perform highly-complex and safety-critical jobs. This study proposed and validated a quantitative model for the study of user performance improvement in a multitasking environment. The Multi-Attribute Task Battery-II (MATB-II) was used in the experiments as a multitasking platform. The proposed model included quantification of stimuli from each MATB-II subtask as baud rate (bits per second), selection of task difficulty and task weight, as well as the rearrangement of task weights. This research followed a two-phase experimental approach. The first phase applied the proposed model and identified a performance baseline for each individual in a multitasking environment, MATB-II. The second phase validated the proposed model using a rearranged set of multitasks for each individual. Individual differences in working memory capacity (WMC) have been estimated as predictors of varying cognitive abilities. This study also investigated the relationship between WMC, task difficulty, and multitasking performance. Significant improvement of user performance was found after the rearrangement of tasks based on the proposed approach. This research provides a framework to quantitatively evaluate multitasking systems and improve human performance in order to understand the interaction between systems and human operators.

A natural interface based on intention prediction for semi-autonomous micromanipulation

Manipulation at micro and nano scales is a particular case for remote handling. Although novel robotic approaches emerge, these tools are not yet commonly adopted due to their inherent complexity and their lack of user-friendly interfaces. In order to fill this gap, this work first introduces a novel paradigm dubbed semi-autonomous. Its aim is to combine full-automation and user-driven manipulation by sequencing simple automated elementary tasks following user instructions. To acquire these instructions in a more natural and intuitive way, we propose a “metaphor-free” user interface implemented in a virtual reality environment. A predictive intention extraction technique is introduced through a computational model inspired from cognitive sciences and implemented using a Kinect depth sensor. The model is compared in terms of naturalness and intuitiveness to a gesture recognition technique to detect user actions, in a semi-autonomous pick-and-place operation. It shows an improvement in user performance in duration and success of the task, and a qualitative preference for the proposed approach as evaluated by a user survey. The projected technique may be a worthy alternative to manual operation on a basic keyboard/joystick setup or even an interesting complement to the use of a haptic feedback arm.

Functional dependability of the display unit software of the BLOK system

Aim. The article is dedicated to the challenges of evaluating the functional dependability of the display unit software (SW) that is part of the BLOK vital integrated onboard system as attributed to program errors within a 24-hour target time. One of the key tasks is the calculation of the values of such SW functional dependability characteristics as accuracy, correctness, security, controllability, reliability, fault tolerance and availability, which are the primary indicators for evaluating the health of safety devices. With all this taken into account, it is to be evaluated whether the checking of the software of the display unit before each trip with a departure test is required. Method. The reference conditions do not contain statistical data of program executions over the course of its maintenance. There is also no information on the structural characteristics of the program (number of operators, operands, cycles, etc.) which prevents the use of statistical models of dependability, such as the Halstead metrics, IBM model or similar ones. That is why the Schumann model was chosen as the initial data definition apparatus. The method of evaluation of the display unit’s functional dependability is based on the findings of [1]. Results. At the first stage, the following initial data values were defined: initial number of defects in the program, program failure rate and probability of correct run. At the subsequent stage, the identified values were used to define such dependability parameters as probability of no-error as the result of program run within a given time, probability of no-failure of display unit as the result of program run within a given time and mean time to program failure. After the probability РSW (t) of no-error as the result of program run within a given time was calculated, such SW dependability attributes as accuracy, correctness, security and controllability were evaluated. After the probability of no-failure of the display unit РR (t) as the result of program run within a given time was calculated, an evaluation was given to such attributes as SW reliability and fault tolerance, while after the mean time to program failure TavSW was calculated, knowing the mean downtime due to elimination of the program error τpdt, the display unit availability for faultless execution of an information process at an arbitrary point in time Cfa was defined. The calculated partial functional availability coefficients for the display unit have shown that pre-trip checking of the unit and immediate elimination of errors, should such be identified, will enable a significant improvement of user performance of the onboard display unit (BIL) in terms of timely notification of the driver on the current operational situation to enable timely train control decision-making.

Position stabilisation and lag reduction with Gaussian processes in sensor fusion system for user performance improvement

In this paper we present a novel Gaussian Process (GP) prior model-based sensor fusion approach to dealing with position uncertainty and lag in a system composed of an external position sensing device (Kinect) and inertial sensors embedded in a mobile device for user performance improvement. To test the approach, we conducted two experiments: (1) GPs sensor fusion simulation. Experimental results show that the novel GP sensor fusion helps improve the accuracy of position estimation, and reduce the lag (0.11 s). (2) User study on a trajectory-based target acquisition task in a spatially aware display application. We implemented the real-time sensor fusion system by augmenting the Kinect with a Nokia N9. In the trajectory-based interaction experiment, each user performed target selection tasks following a trajectory in (a) the Kinect system and (b) the sensor fusion system. In comparison with the Kinect time-delay system, our system enables the user to perform the task easier and faster. The MSE of target selection was reduced by 38.3 % and the average task completion time was reduced by 26.7 %.

Joint and distributed scheduling with dynamic power control in multicell orthogonal frequency division multiple access networks

This study addresses the issue of intercell interference coordination in a multicell orthogonal frequency division multiple access network with universal frequency reuse, which aims at improving the network spectral efficiency, especially for the cell edge areas. According to different degrees of information sharing within the engaged network, both a joint and a distributed solution are proposed respectively trying to determine the most appropriate power control strategy along with the user scheduling policy. The joint power control and user scheduling scheme with full access to the network information is capable of gaining considerable enhancement on the network capacity and also a performance improvement for users suffering from strong intercell interferences. The distributed scheme with the same purpose manages to adapt the power control and user scheduling strategy on the basis of dynamic programming with respect to both current and future utility of the network with only local information available. Numerical results have shown the advantages of the proposed schemes in achieving better spectral efficiency under both joint and distributed circumstances.

Discussion on Strategies for Adaptive Dynamical Clustering in Cooperative Multi-point Downlink Transmission Systems

As one of the most promising techniques for next generation wireless communication, coordinating transmission by multiple points (i.e. radio access points or base stations) have recently attracted a lot of attention because of its potential for intercell co-channel interference mitigation and significant spectral efficiency improvement. This paper firstly presents the system structure and mathematical signal model for multipoint coordinating downlink transmission, and then gives a detailed discussion on dynamical cell-clustering strategies, scheduling utility-metric and resources allocation scheme in adaptively forming cooperation cluster of cells based on detected system parameters, where the user is serviced by a cluster selected from a set of clusters that has been adapted to its particular network circumstance and location. Some numerical analysis shows that with dynamical cell-clustering, a clustered supercell with 7-cell is relatively reasonable for spectral efficiency improvement. Also, some simulation results are given to show that adaptive dynamical cell-clustering methods are more beneficial to user performance improvement.

Adaptive dynamical cell-clustering in coordinated multipoint network-MIMO transmission systems

As one of the most promising techniques for next generation wireless communication, coordinating transmission by multiple points (i.e., radio access points or base stations) have recently attracted a lot of attention because of its potential for intercell co-channel interference mitigation and significant spectral efficiency improvement. This paper firstly presents the system structure and mathematical signal model for multipoint coordinating downlink transmission, and then gives a detailed discussion on dynamical cell-clustering strategies, scheduling utility-metric and resources allocation scheme in adaptively forming cooperation cluster of cells based on detected system parameters, where the user is serviced by a cluster selected from a set of clusters that has been adapted to its particular network circumstance and location. Some numerical analysis shows that with dynamical cell-clustering, a clustered supercell size of 7 is a reasonable choice for improving spectral efficiency. Also, some simulation results are also given to show that the proposed adaptive dynamical cell-clustering methods are beneficial to user performance improvement.

Development of a Conceptual Query Language: Adopting the User-Centered Methodology

The pervasiveness of end-user computing tools in the home and in workplaces, as well as the linkage of PCs into networks, have led to a convergence of end-user computing and corporate computing. As a result of this phenomenon, and because the productivity of end-users with these tools depends on how well suited the tools are to users, the issue of the suitability of computing tools for end-users is a valid concern for organizations. In the area of databases (DBs), the concern is that of ensuring the suitability of ad hoc querying and reporting tools for end-users. The significance of this concern lies in the realization that organizations and DB users are depending on more and more complex DBs, for example those being placed on the Web. DB researchers therefore argue for the adoption of the user-centered approach in developing these tools, to ensure suitability. The adoption of this approach in the development of the Conceptual Query Language (CQL) is reported in this paper. Also discussed is the series of experimental tests conducted to ascertain the impact of the approach on the usability of CQL. The test results suggest an improvement in user performance with and perception of CQL as a result of user participation in its development process.

Web Graduate Courses on Benign Urban Water Systems: Optimal Complexity and User Performance Improvement

Nineteen graduate students from various countries participated during Jan-Apr 2000 in a dual graduate course delivered on one web home page. Five professors fr…

A system for query comprehension

A major difficulty of query writing is that users do not fully understand queries. A system providing feedback is proposed so as to enable users to better understand their queries. It is a multi-functional rule-based system. In addition to providing an English translation for the query, it pin-points syntax errors, and suggests possible solutions. It also finds likely semantic errors, and provides possible solutions. The system was implemented for a query language based on the entity relationship model. It is expected to lead to better user performance. Empirical testing showed significant improvement in user performance with the feedback system. The system can be used for computer-aided training and in actual operations.