Alleviation of Delay in Tele-Surgical Operations using Markov Approach based Smith Predictor

The acceptance of tele-robotics and teleoperations through networked control system (NCS) is increasing day-by-day. NCS involves the feedback control loop system wherein the control components such as actuators and sensors are controlled and allowed to share their feedback over real time network with distributed users spread geographically. The performance and surgical complications majorly depend upon time delay, packet dropout and jitter induced in the system. The delay of data packet to the receiving side not only causes instability but also affect the performance of the system. In this article, author designed and simulate the functionality of a model-based Smith predictive controller. The model and randomized error estimations are employed through Markov approach and Kalman techniques. The simulation results show a delay of 49.926ms from master controller to slave controller and 79.497ms of delay from sensor to controller results to a total delay of 129.423ms. This reduced delay improve the surgical accuracy and eliminate the risk factors to criticality of patients’ health.

Lane Change Control Combined with Ramp Metering: A Strategy to Manage Delays at On-Ramp Merging Sections

Control measures at merging locations aimed at either the mainline traffic or on-ramp traffic do not lead to a fairness in the distribution of total delay across the two streams. This paper presents a control strategy of combining a lane change control with a ramp metering system at motorway merges. The control strategy presents the opportunity to control the delays incurred at the two traffic streams of the merge. An optimization problem is formulated for a multilane motorway with an on-ramp with the aim to minimize the total travel time of the system. The proposed strategy is tested using an incentive-based lane-specific traffic flow model. Results revealed a 17% reduction in the total travel time due to the proposed strategy. Moreover, it was shown that the distribution of delays over the mainline and on-ramp could be controlled via the proposed strategy. The performance of the combined control was also compared to the individual control measures. It was observed that the individual control measures (lane change only and ramp metering only) lead to high delays on either the mainline or on-ramp compared to the combined control, where the balance between the delay for the drivers on the mainline and on-ramp could be regulated. The combined lane change and ramp metering control presents opportunities for the road authorities to manage the total delay distribution across the two traffic streams.

A Novel Clock Skew Estimator and Its Performance for the IEEE 1588v2 (PTP) Case in Fractional Gaussian Noise/Generalized Fractional Gaussian Noise Environment

Papers in the literature dealing with the Ethernet network characterize packet delay variation (PDV) as a long-range dependence (LRD) process. Fractional Gaussian noise (fGn) or generalized fraction Gaussian noise (gfGn) belong to the LRD process. This paper proposes a novel clock skew estimator for the IEEE1588v2 applicable for the white-Gaussian, fGn, or gfGn environment. The clock skew estimator does not depend on the unknown asymmetry between the fixed delays in the forward and reverse paths nor on the clock offset between the Master and Slave. In addition, we supply a closed-form-approximated expression for the mean square error (MSE) related to our new proposed clock skew estimator. This expression is a function of the Hurst exponent H, as a function of the parameter a for the gfGn case, as a function of the total sent Sync messages, as a function of the Sync period, and as a function of the PDV variances of the forward and reverse paths. Simulation results confirm that our closed-form-approximated expression for the MSE indeed supplies the performance of our new proposed clock skew estimator efficiently for various values of the Hurst exponent, for the parameter a in gfGn case, for different Sync periods, for various values for the number of Sync periods and for various values for the PDV variances of the forward and reverse paths. Simulation results also show the advantage in the performance of our new proposed clock skew estimator compared to the literature known ML-like estimator (MLLE) that maximizes the likelihood function obtained based on a reduced subset of observations (the first and last timing stamps). This paper also presents designing graphs for the system designer that show the number of the Sync periods needed to get the required clock skew performance (MSE = 10–12). Thus, the system designer can approximately know in advance the total delay or the time the system has to wait until getting the required system’s performance from the MSE point of view.

Blockchain-Enabled Task Offloading and Resource Allocation in Fog Computing Networks

To address the data security and user privacy issues in the task offloading process and resource allocation of the fog computing network, a blockchain-enabled fog computing network task offloading model is proposed in this paper. Furthermore, to reduce the network utility which is defined as the total energy consumption of the fog computing network and the total delay of the blockchain network, a blockchain-enabled fog computing network task offloading and resource allocation algorithm (TR-BFCN) is proposed to jointly optimize the task offloading decision and resource allocation. Finally, the original nonconvex optimization problem is converted into two suboptimization problems, namely, task offloading decisions and computational resource allocations. Moreover, a two-stage Stackelberg game model is designed to obtain the optimal amount of purchased resource and the optimal resource pricing. Simulation results show that the proposed TR-BFCN algorithm can effectively reduce the network utility compared with other algorithms.

Stakeholders’ Insight on the Delay of Constructions Projects in the Makkah Region- KSA

Aims: This study aims to identify the major causes of delays in construction projects in the Makkah region of Saudi Arabia. It investigates the opinions of different stakeholders separately to ensure partiality and objectivity. Background: Saudi Arabia's construction industry is experiencing rapid expansion, with no shortage of contracts in any sector, either from housing or utilities to transport infrastructure. Public spending is driving the contracting industry forward [Oxford]. The construction industry contributed between 30% to 40% of the non-oil productive sectors at the end of each National Development Plan from 1980 to 2000. Makkah receives around two million pilgrims during the annual Hajj and more than 20 million visitors for performing Umrah (Al-Emad). Substantial public funds have been spent on construction projects to develop Makkah during recent years. Real estate, infrastructure, hospitals, and retail sectors are among those most likely to benefit. Most of these projects suffered delays and their consequences. The Saudi Ministry of Municipal and Rural Affairs (MOMRA) and the Ministry of Transportation acknowledged public construction project delays. They reported that approximately 75% of them exceeded their scheduled time. This is one of the main reasons to conduct this study. Methods: In this study, a comprehensive questionnaire has been developed, consisting of seventy-three causes of delay. The questionnaire was organized in the form of an importance scale. Respondents were asked to indicate their responses by ticking a column of the impact and frequency of each of the causes and construction delay in terms of 5 = very important, 4 = important, 3 = somewhat important, 2 = less important, and 1 = not important. A hundred fifty questionnaires were distributed by hand to the contractor, the consultant, and the owner in the Makkah region of Saudi Arabia. Ninety-seven forms were filled, received, and processed. The survey data were grouped into eight significant categories: owner, consultant designer, supervisor, contractor, material, labor, site, and external factors. A ninth group is left for the participants to add whatever they think of furtherer causes of delay. Results: The evaluation of the three separate surveys conducted on the responses of the owner, the contractors, and the consultant supervisor, show that the contractor is mainly responsible for the delay. Around 47% of the top ten delay factors fall in the contractor delay factors followed by laborers and owners. Three categories have not been mentioned in the top ten as delay category, including supervisors, materials, and external factors. Only one delay factor was found to be shared among the three-survey group, which is related to the labor category, that is, low productivity of labor. Conclusion: Three separate surveys have been conducted to investigate the delay in the construction industry in the Makkah region of Saudi Arabia. The surveys contain a questionnaire of seventy-three possible delay factors investigating the opinions of the three main stakeholders in the construction industry: the owners, the contractors, and the consultants. The evaluation of the survey impacts shows that the contractor is mainly responsible for the delay, followed by laborers and then the owners. One common delay factor was found among the three surveyed groups related to the labor category; that is, low productivity of labor. In frequency, the contractor category also occupied the highest percentage of the total delay contributors. Another common delay factor was found among the three surveyed groups, also related to the contractor category, that being the lack of risk evaluation by the contractor.

Compensation for Delays and Losses of Packages in Dynamic Online Games

A couple of decades ago, data rates on the network were measured in kilobytes per second, and even then, online game developers had some problems with the packet loss and transmission delays. Now the transfer rate is hundreds of times higher, and the problem of delay compensation is even more relevant.For many dynamic online games, a transmission delay of as little as 20 ms can be quite noticeable, negatively affecting the gameplay and emotions of the game, which can repel players.The problem is exacerbated by the fact that along with the need to compensate for the time of delivery of packets, on the client side there are other non-network factors that are beyond the control of developers, which make the total delay 5-10 ms longer. Because of this, the desire to get rid of network delays as much and as well as possible becomes a necessity, and developers are forced to look for optimal ways to solve this problem.The problem statement is as follows: to review the causes of delays in online games and possible solu- tions, as well as the advantages and disadvantages of certain approaches. The problem is considered at the 4 levels of the TCP / IP network model, as well as at the application level. The approaches are given for the most commonly used protocols for each layer, but basic ideas can be easily transferred to other implementations.The main causes of delays under consideration: propagation delay, router queue delay, transmission delay, and processing delays.This article shows the impact of network delays on the online games and the ways to compensate for them, along with the theory of data transmission protocols in the network and the ways to solve the problems that arise in the development of algorithms.Recommendations for solving the compensation problem can be taken into account when designing and launching online shooters, strategies, etc. Thanks to the given receptions it is possible to minimize the general delay on the transfer of packets in a network, thanks to which the game on the client looks as if the player plays in the Single Player mode.

Impact Assessment of Driver Distraction by Cellphone on Start-up Lost-time and Average Saturation Headway at Signalized Intersections Based on Vehicle Position in the Queue

Cellphone usage has a significant impact on signalized intersections' capacity and level of service. This study investigated the impact of cellphone usage on signalized intersection capacity and level of service in Dammam Metropolitan Area, Saudi Arabia. The data included 183 useful cycles and 2407 start-up lost time and average saturation headway values at cycles with cellphone usage and cycles without cellphone usage at 24 signalized intersections. The main hypothesis of the study is that cellphone usage increases the start-up lost time at signalized intersection capacity. The secondary hypothesis is that cellphone usage increases the average saturation headway at signalized intersections. Normal distribution and z-test were conducted to assess whether there is a significant increase in average saturation headway and start-up lost time. The study found a significant increase in start-up lost time of about 0.7 seconds but found no significant increase in average saturation headway due to cellphone usage. Also, start-up lost time increases as vehicles of cellphone users get closer to the stop line of the signalized intersections. Thus, cellphone usage decreases the progression of 13 vehicles per hour due to a reduction in effective green time, increases total delay, and deteriorates the level of service. The study can assist transportation and traffic officials to optimize signal operation to mitigate the impact of cellphone usage and improve urban transportation.

The Impact of Uncertainty on Pedestrians’ Decision to Start Roadway Crossing during the Clearance Phase

Clearance phase at signalized crosswalks is an important parameter of pedestrians’ safety because it helps them to complete the crossing before the green signal for vehicles. However, there is the issue of pedestrian decision as to whether to cross if they arrive at the crosswalk during the clearance phase, which represents a violation in many countries. Due to the proof that pedestrian violations multiply the risk of traffic accidents, in this study, the tendency of pedestrians to commit violations during the clearance time has been researched. With the aim of proposing the design of the pedestrian traffic lights, which could decrease the frequency of pedestrian violations, the comparison of pedestrians behaviour at crosswalks with and without a countdown timer during the clearance time was made, based on the data collected in the video recording. Chi square independency test showed that there is a statistically significant difference in the behaviour of pedestrians during the clearance time, depending on the existence of the timer, as well as the fact that pedestrians behave in a safer manner if there is no clearance time shown on the timer. The total delay rate on the roadway during the red signal, which was the consequence of starting the crossing during the clearance time or subsequent violations, was 1.3 times higher at the crosswalks with the countdown timer. This research was unique because for the first time, two-phase pedestrian crossings on the roadway with the median refuge island in the sense of clearance time were analysed, in spite of the previous proof that pedestrians are more likely to commit violations during the red signal in that kind of roadway. Another novelty in the research was pedestrians following till the end of crossing, due to the possibility of subsequent violations. With the means of binary logistic regression, different factors which affect pedestrians’ behaviour during the clearance time have been determined and they differ depending on the existence of the timer. At the pedestrian crosswalks with the timer, contributing factors have been determined, such as gender, the number of waiting pedestrians, distractions, arrival time, and age. If there is no timer, the contributing factors are the following: the number of crossing pedestrians, distractions, group, position of pedestrians in relation to the vehicle, the number of traffic lanes, and age. Based on the obtained results, a new design of the pedestrian traffic lights was proposed.

Precipitation Water Vapour Variation in the East Java Region from Data CORS Using GIPSY

The Global Navigation Satellite System is being developed as an atmospheric remote sensing system through the calculation of Zenith Total Delay. The development of the Continous Operating Reference Station encourages research investigations into Zenith Tropospheric Delay with continuous data and good spatial resolution. This research studies the characteristics of spatial and temporal variations of the Zenith Wet Delay in East Jawa. The case study in East Jawa Province uses 16 Continous Operating Reference Stations. As a comparison, meteorological data from the Badan Meteorologi, Klimatologi, and Geofisika stations are used.The Zenith Total Delay and Zenith Wet Delay values from the Continous Operating Reference Station data are calculated using GIPSY 6.4 Software. The Zenith Wet Delay values are gridded using the kriging method with the size of the grids being 0,25 x 0,25. The ZWD value comparison from the Continous Operating Reference Station and meteorology data has a strong correlation with a coefficient value of 0,712. The mean of Zenith Wet Delay’s trend is increasing by about 0,712 mm/yr. The characteristics of the spatial and temporal variations of the ZWD value are influenced by the monsoon of Asia-Australian, which causes dry and rainy seasons, global phenomena such as El Nino and La Nina, rainfall, local meteorological conditions such as temperature and humidity, weather, and the topography of the stations.

Effect of broadcast and precise satellite orbits in the estimation of Zenith tropospheric delay and integrated precipitable water vapour from GPS

Global Positioning System (GPS) estimates the total delay in zenith direction by the propagation delay of the neutral atmosphere in presence of water vapour present in the troposphere. This total delay has been treated as a nuisance parameter for many years by the geodesists. The above delay have two parts dry delay and wet delay and known as Zenith Hydrostatic Delay (ZHD) and Zenith Wet Delay (ZWD) respectively. The Integrated Precipitable Water Vapour (IPWV) is estimated through ZWD overlying the receiver at ground-based station. The accuracy of the above said estimates depends on the quality of the predicted satellite orbits, which are not the same for each individual satellite. India Meteorological Department (IMD) is operationally estimating the IPWV on near real time basis at five places and matches fairly well (error ~6.7 mm) with Radisonde (RS) data. This paper examine the effect of International GPS Service (IGS) predicted precise orbits and near real time predicted rapid or broadcast orbits supplied by the Scripps Orbit and Permanent Array Center (SOPAC) on Zenith Total Delay (ZTD) and IPWV estimates by calculating the mean Bias and Root Mean Square Error (RMSE) for ZTD and IPWV in mm for all the five stations. The observed bias for ZTD is almost of the order of less than 1 mm in most cases and RMSE is less than 6 mm. Similarly the bias observed in the case of derived IPWV is almost negligible and RMSE is less than 1 mm.