Directional Path Research Articles

Millimeter Wave and Sub-Terahertz Spatial Statistical Channel Model for an Indoor Office Building

Millimeter-wave (mmWave) and sub-Terahertz (THz) frequencies are expected to play a vital role in 6G wireless systems and beyond due to the vast available bandwidth of many tens of GHz. This paper presents an indoor 3-D spatial statistical channel model for mmWave and sub-THz frequencies based on extensive radio propagation measurements at 28 and 140 GHz conducted in an indoor office environment from 2014 to 2020. Omnidirectional and directional path loss models and channel statistics such as the number of time clusters, cluster delays, and cluster powers were derived from over 15,000 measured power delay profiles. The resulting channel statistics show that the number of time clusters follows a Poisson distribution and the number of subpaths within each cluster follows a composite exponential distribution for both LOS and NLOS environments at 28 and 140 GHz. This paper proposes a unified indoor statistical channel model for mmWave and sub-Terahertz frequencies following the mathematical framework of the previous outdoor NYUSIM channel models. A corresponding indoor channel simulator is developed, which can recreate 3-D omnidirectional, directional, and multiple input multiple output (MIMO) channels for arbitrary mmWave and sub-THz carrier frequency up to 150 GHz, signal bandwidth, and antenna beamwidth. The presented statistical channel model and simulator will guide future air-interface, beamforming, and transceiver designs for 6G and beyond.

Quantum dot heterostructure with directional charge transfer channels for high sodium storage

Transition metal carbides (TMCs) are viewed as promising anode materials for sodium ion batteries due to high conductivity and chemical stability. However, the sluggish kinetics of Na+ and large volume expansion has significantly hindered their practical applications. Herein, we report a universal strategy of loading high work-function metal quantum dots (QDs) to provide a directional charge transfer path by constructing the interfacial Mott-Schottky heterojunction, which broadens space-charge regions and increases regional charge densities. As a proof of concept, 1D hollow tubular nanostructure embedded with Cu QDs and Mo2C/MoO2 nanoparticles was ingeniously synthesized through an in-situ polymerization method with dual chelating agents. Benefiting from both QDs with maximized metal utilization and Mott-Schottky heterostructure with charge transfer acceleration, the electrode displays an unprecedented capacity and rate performance for Mo2C-based materials along with ultra-long cycling stability. This work provides an untraditional strategy to enhance sodium storage capability of TMCs, which is significant for development of advanced energy storage devices.

A novel approach to optimising well trajectory in heterogeneous reservoirs based on the fast-marching method

To achieve efficient recovery of subsurface energy resources, a suitable trajectory needs to be identified for the production well. In this study, a new approach is presented for automated identification of optimum well trajectories in heterogeneous oil/gas reservoirs. The optimisation procedures are as follows. First, a productivity potential map is generated based on the site characterisation data of a reservoir (when available). Second, based on the fast-marching method, well paths are generated from a number of entrance positions to a number of exit points at opposite sides of the reservoir. The well trajectory is also locally constrained by a prescribed maximum curvature to ensure that the well trajectory is drillable. Finally, the optimum well trajectory is selected from all the candidate paths based on the calculation of a benefit-to-cost ratio. If required, a straight directional well path, may also be derived through a linear approximation to the optimised non-linear trajectory by least squares analysis. Model performance has been demonstrated in both 2D and 3D. In the 2D example, the benefit-to-cost ratio of the optimised well is much higher than that of a straight well; in the 3D example, laterals of various curvatures are generated. The applicability of the method is tested by exploring different reservoir heterogeneities and curvature constraints. This approach can be applied to determine the entrance/exit positions and the well path for subsurface energy system development, which is useful for field applications.

Millimeter-Wave Propagation Measurement and Modeling in Indoor Corridor and Stairwell at 26 and 38 GHz

Accurate propagation characteristics are essential for future indoor millimeter-wave (mmWave) small cell network planning. This paper presents propagation measurements at 26 GHz and 38 GHz which are important candidate bands for fifth generation mmWave communication. Measurements are conducted in an indoor corridor, as well as a stairwell whose mmWave channel is seldom investigated before. In these measurements, an omnidirectional biconical antenna is used as transmitter and a steerable directional horn antenna is used as receiver. The directional and omnidirectional path loss exponents, shadow factors, cross-polarization discrimination ratios and root-mean-square delay spreads are analyzed for both line-of-sight and non-line-of-sight scenarios in both co-polarization and cross-polarization, and these characteristics are compared for different frequencies and environments. It is found obvious depolarization phenomenon in non-line-of-sight scenario for higher frequency. Compared to the corridor, the stairwell has larger path loss exponents and root-mean-square delay spreads, and the depolarization is also more evident in stairwell. The results in this paper are beneficial to building efficient and robust indoor mmWave communication systems.

Impact of Artificial Intelligence-enabled Software-defined Networks in Infrastructure and Operations: Trends and Challenges

The emerging technologies trending up in information and communication technology are tuning the enterprises for betterment. The existing infrastructure and operations (I&O) are supporting enterprises with their services and functionalities, considering the diverse requirements of the end-users. However, they are not free of the challenges and issues to address as the technology has advanced. This paper explains the impact of artificial intelligence (AI) in the enterprises using software-defined networking (SDN) in I&O. The fusion of artificial intelligence with software-defined networking in infrastructure and operations enables to automate the process based on experience and provides opportunities to the management to make quick decisions. But this fusion has many challenges to be addressed. This research aimed to discuss the trends and challenges impacting infrastructure and operations, and the role of AI-enabled SDN in I&O and discusses the benefits it provides that influence the directional path. Furthermore, the challenges to be addressed in implementing the AI-enabled SDN in I&O shows future directions to explore.

The Association Between Health, Social Engagement, and Psychological Well-Being Among Older Adults in China

Psychological health and health-related quality of life of older adults have been long minimized by caregivers, service providers and the society in developing countries, such as China. According to the Stress Process Model, the stress of physical disadvantages influences mental health outcomes directly and indirectly. However, being socially engaged has the potential to reduce disease burden and improve psychological wellbeing of older adults. The purpose of this study is to examine the role played by social engagement in the pathway through which physical health predicts mental health. Using the WHO Study on Global AGEing and Adult Health China wave 2010, 6,276 individuals ages 60 years and older were included for analyses. Structural equation modeling was used to construct a directional path leading from the functioning and chronic disease, impacting the social engagement, in turn impacting the psychological wellbeing. All variables in this model are latent constructs. Functioning and chronic diseases in later life were associated with social engagement and psychological wellbeing, and the link between social engagement and psychological wellbeing was also significant. The effect of function was greater than that of chronic diseases. Though the significant indirect effect of physical health on psychological wellbeing was not supported in this study, this study suggests the multiple roles of social engagement as coping resources in the stress process of physical impairment and illness of older adults. This present study also adds to the existing literature by exploring how SEM methods can be applied to studies of social engagement.

Industrial and agricultural production in the Perm Territory: economics and organization aspects

The article considers a methodology for analyzing the organization of industrial and agro-industrial production in the region using the method of correlation pleiades. This allowed the authors to draw conclusions regarding the interconnectedness of spatial and temporal data in the region’s space, as well as to identify quantifiable groups of indicators that are crucial in the region’s economy, in the sustainable development of individual territories, and general trends that form the directional path of the region’s development.

Slide-Drilling Guidance System Optimizes Directional Drilling Path

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 194096, “Slide-Drilling Guidance System for Directional-Drilling Path Optimization,” by Can Pehlivanturk and John D’Angelo, The University of Texas at Austin, and Dingzhou Cao, Anadarko, et al., prepared for the 2019 SPE/IADC International Drilling Conference and Exhibition, The Hague, 5–7 March. The paper has not been peer approved. The amount of uncertainty related to directional drilling makes accurate drilling challenging, leaving much to human know-how and interpretation. Additionally, few path-planning methods in the literature consider the directional steering tool being used. The formulation of the problem of optimization varies greatly between rotary steerable systems (RSS) and mud-motor configurations. Additional cost functions and constraints exist for mud-motor use, which significantly increases the complexity of the problem. A slide-drilling-guidance system is proposed to combat this issue and to help automate directional drilling. Introduction Despite the numerous technological advancements that made directional drilling a reality, directional drilling is still viewed more as an art than as a science. The drillstring and penetrated rock formations are complex systems whose interaction makes prediction and planning highly uncertain. Analytical, geometric approaches have sought to formulate the curvature of the well path in a way that eases the planning process and ensures smooth trajectories. The literature on directional drilling is rich in well-path-optimization methodologies based on operating constraints and well-path geometry. However, few of these methods seem to consider the tool used to generate the well path, and those that do typically use RSS because these yield better results from a technical perspective. Mud motors, however, are still used extensively because of cost effectiveness. The complete paper proposes a directional-drilling guidance system targeted at downhole motors and slide drilling to generate optimal well paths and associated slide-drilling instructions. Instead of a simplistic shortest-path approach, various cost functions aimed at maximizing the value of the well are considered. For wellbore-propagation prediction, a computationally efficient and accurate model is used. The proposed methodology is built into a software package and is being developed and implemented currently for use in the real-time drilling (RTD) system of an operator. The three main modules of the software are discussed in detail in the complete paper. The wellbore-propagation model predicts the evolution of the borehole and returns the predicted 3D path given the initial condition and a slide sheet. The fitness-evaluation module calculates the fitness of the 3D path using a cost function and returns a scalar value representing the overall value of the path. The genetic-algorithm solver generates candidate slide sheets and approaches an optimal slide sheet by iterating over generations. Software Implementation Graphical User Interface (GUI). The GUI serves as a tool to visualize the well under consideration and to study the optimization results and the effectiveness of the approach. The GUI is written in MATLAB and uses the Runtime environment. Here, the data for the planned path and the actual survey data are loaded. The planned path and the surveyed path (up to the time for which such data are available) are displayed.

Enhancing Passenger Comfort in Autonomous Vehicles Through Vehicle Handling Analysis and Optimization

Autonomous Vehicles (AVs) offer significant advantages in terms of traffic and fuel efficiency accident prevention, and reduced travel time. `Sense-plan-act' cycle of the AV has been designed and implemented to achieve a high level of active safety that considerably reduces the risk to passengers and pedestrians. However, within existing path planning and tracking algorithms, the subject of passenger comfort has received less attention compared to other AV topics. This paper is aimed at characterizing vehicle handling criteria and path profiles configuration in order to identify self-driving requirements for passenger comfort. The emphasis is given to the efficacy and usability of the classical handling analysis methods from a self-driving perspective. To these aims, we initially establish a framework which is defined by comfortable path profiles and a versatile handling model of an AV. Then, we introduce a directional path tracking unit which optimally implements AV's trajectories using a controller and a speed regulator. The path tracking unit includes a multi-objective optimizer enabling improvement the handling behavior of the AV. The integration of the proposed methodology into the state-of-the-art AVs' control system can lead to an enhanced comfort level.

Definition of failure criterion for frozen soil under directional shear-stress path

Definition of failure criterion for frozen soil under directional shear-stress path

Fem stress analysis of a barrel reamer

Abstract Horizontal Directional Drilling (HDD) is a method of installing underground pipelines, cables and service conduit through trenchless methods. The tools and techniques used in the HDD process are an outgrowth of the oil well drilling industry, too. Installation of a pipeline by HDD is a three stages process. The first stage consists of directionally drilling a small diameter pilot hole along a designed directional path. Drilling fluid is pumped through the drill pipe to the drill bit where high pressure jets and the bit will grind the soils ahead of the drill stem. The second stage involves enlarging this pilot hole to a diameter suitable for installation of the pipeline. A reamer is pulled back and rotated while pumping drilling fluid to cut and remove solids to enlarge the hole. A kind of reamer is the subject of this paper. The final stage consists of pulling the pipeline back into the pre-reamed hole. The most important part of the mechanical analysis is to define the boundary conditions for operating situations when the tool is under maximum load. In this paper we present a helpful description for giving boundary conditions to perform the numerical simulation of a barrel reamer.

Comprehensive preference learning and feature validity for designing energy-efficient residential buildings using machine learning paradigms

Having a reliable approximation of heating load (HL) and cooling load (CL) is a substantial task for evaluating the energy performance of buildings (EPB). Also, the appearance of soft computing techniques has made many traditional methods antiquated. Thus, the main effort of this study was to evaluate the capability of several learning methods for appraising the HL and CL of a residential building. To this end, a proper dataset consisting of eight influential factors was provided. To simplify the problem, we executed feature validity by using a correlation-based feature subset selection (CfsSubsetEval) technique. The results of this process showed that wall area, overall height, orientation and glazing area have the most significant impact on the HL and CL simulation. After preparing the suitable dataset, sixteen learning methods namely, elastic net (EN), Gaussian process regression (GPR), least median of squares regression (LMSR), multiple linear regression (MLR), multi-layer perceptron regression (MPR), multi-layer perceptron (MLP), radial basis function regression (RBFR), sequential minimal optimization regression (SMOR), functions XNV, lazy K-star, lazy LWL, rules decision table (RDT), M5Rules, alternating model tree (AMT), directional path consistency (DPC), and Random Forest (RF) were developed in Weka environment to forecast the HL and CL variables. Referring to the results, it was concluded that RF, lazy K-star, RDT and AMT outperform other predictive models. Also, comparing the results with the results of the previous studies showed that the applied feature reduction not only did not disturb the learning process but also has enhanced the performance of models. Also, due to the excellent accuracy of the MLP, a formula was derived from the optimized structure of it to predict the HL and CL variables.

Blockchain platform and future bank competition

PurposeGiven that Blockchain technology poses a growing challenge to the banking industry, this paper aims to analyse the innovation of Blockchain banking with regard to its systemic dimension, as well as dynamics of competition. The empirical research demonstrates how the systemic characteristics of Blockchain banking relate to the pursuit of strategies and to what extent these strategies influence the directional path and level of technology diffusion.Design/methodology/approachThe research study uses a case study methodology to explore the strategic competition of Blockchain banking. The study proposes the systemic innovation model for analysing and tracking the path of innovations. The model can be applied to any industry to understand the process of innovation development and the strategies to win market share in the banking industry. This research makes a contribution towards the theory of technology diffusion to understand the directional path of innovations.FindingsThe analyses of findings reveal the situation whereby most banks still compete to create their own Blockchain banking systems. The analyses, based on the systemic innovation model, also shows the low systemic feature of Blockchain banking at present. From the technology diffusion perspective, the future of Blockchain banking may need cross-chain interoperability to support a full spectrum of payments and value exchanges on the internet of things.Originality/valueThe main contribution of this paper is the systemic analysis of the latest innovation of Blockchain banking. Given that the research also includes the major banking innovation cases of ATM/cash cards, credit cards and electronic fund transfer at the point of sale/debit cards, the comparative analyses offer strategic insights to predict the progress, as well as pattern of technology development and diffusion for the case of Blockchain banking.

Millimeter-Wave Base Station Diversity for 5G Coordinated Multipoint (CoMP) Applications

Millimeter-wave (mmWave) will be used for fifth-generation (5G) wireless systems. While many recent empirical studies have presented propagation characteristics at mmWave bands, macrodiversity and Coordinated Multipoint (CoMP) have not been carefully studied. This paper describes a large-scale mmWave base station diversity measurement campaign at 73 GHz in an urban microcell (UMi) in downtown, Brooklyn, NY, USA, and provides the first detailed analysis of CoMP and macrodiversity performance based on extensive measurements. The research employed nine different base station locations in a 200 m by 200 m area and considered 36 individual transmitter-receiver combinations for extensive co- and cross-polarized varying directional beam channel impulse response measurements. From the measured data, hypothesis testing with cross-validation shows that large-scale shadow fading of directional path loss at an RX from multiple base stations can be modeled as being independent. To consider life-like human blockage in CoMP and macrodiversity analysis, simulated human blockage traces are superimposed on the directional measurements to quantitatively show that a user that is served by multiple base stations undergoes dramatically less outage in the presence of rapid fading events, compared to a single serving base station. Moreover, the base station diversity measurements are used to determine the effectiveness of downlink precoding techniques for mmWave CoMP. While results show that the coordination can improve network performance by suppressing interference when it exists, nearly half of the 680 000 directional CoMP measurements (~43%) result in no interference for either user, meaning that macrodiversity alone may offer sufficient link and capacity improvement and that CoMP may not be necessary for interference coordination at mmWave when narrow directional beams are used.

A virtual reality head stability test for patients with vestibular dysfunction.

The contribution of visual information to standing balance in patients with vestibular dysfunction varies between patients. Sensitive tools to detect kinematic response to visual perturbation are needed to individualize treatment. Using the Oculus Rift headset and sensors, we developed a novel virtual reality (VR) test of head stability (HST) in response to visual perturbation. During the test, head movements were tracked in six degrees-of-freedom. The purpose of this pilot study was to test the sensitivity of the VR_HST to differences between patients with vestibular dysfunction and controls. Seventeen patients and 16 controls performed static balance tasks with eyes closed (feet together or tandem on floor and foam) and observing 'moving stars' (amplitude 32 mm, frequency 0.2 Hz) via the Oculus (tandem). Directional Path and Root Mean Square Velocity were calculated for postural and head oscillations. Postural sway differed significantly between groups when standing on foam with feet together and on floor while observing the 'moving stars' task. Head oscillations were larger among patients, primarily in pitch, yaw, and roll rotation. The VR_HST was found to be sensitive to differences between small and diverse groups. Its clinical utility should be studied in larger samples of patients with vestibular dysfunction.

Head mounted displays for capturing head kinematics in postural tasks

Tracking head motion in a simple, portable and accurate manner during performance of postural tasks in a virtual reality environment could have important implications for investigating normal and pathological head kinematics. We investigated concurrent validity of head tracking of two Head Mounted Displays (HMDs), Oculus Rift and HTC Vive, vs. a gold-standard motion capture system (Qualisys). Head kinematics of N = 20 healthy young adults was quantified during static and dynamic postural tasks. While wearing the Oculus Rift or HTC Vive, participants observed moving stars (static tasks) or a flying ball (dynamic task). Head kinematics were recorded simultaneously by the Rift or Vive and Qualisys camera system. We calculated head directional path, acceleration in 6 directions and volume of translation movement. Intra-Class Correlations (ICC) and 95% Limits of agreement were calculated. Most ICC values were around 0.9 with several at 0.99 indicating excellent agreement between the HMDs and Qualisys. Weaker agreement was observed for vertical displacement during a static task and moderate agreement was observed pitch and yaw displacement during a dynamic task. A negative bias of a small magnitude (indicating more movement in VR) was observed for most variables in static tasks, while a positive bias was observed for most variables in the dynamic task (indicating less movement in VR). Our results generally support the concurrent validity of Oculus Rift and HTC Vive head tracking during static and dynamic standing tasks in healthy young adults. Specific task- and direction-dependent differences should be considered when planning measurement studies using these novel tools.

A colloidal heterostructured quantum dot sensitized carbon nanotube-TiO2 hybrid photoanode for high efficiency hydrogen generation.

Solar-driven photoelectrochemical (PEC) hydrogen (H2) generation is a promising approach to harvest solar energy for the production of a clean chemical fuel. However, the low photon-to-fuel conversion efficiency and long-term stability of PEC devices are major challenges to be addressed to enable large-scale commercialization. Here we report a simple, fast and cost-effective approach to fabricate high efficiency and stable PEC devices for H2 generation, by fabricating a hybrid photoanode obtained by incorporating small amounts of multiwall carbon nanotubes (MWCNTs) into a TiO2 mesoporous film and sensitizing with colloidal heterostructured CdSe/(CdSexS1-x)5/(CdS)2 quantum dots (QDs). The latter were specially designed to accelerate the exciton separation through a band engineering approach. The PEC devices based on the TiO2/QD-MWCNT (T/Q-M) hybrid photoanode with an optimized amount of MWCNTs (0.015 wt%) yield a saturated photocurrent density of 15.90 mA cm-2 (at 1.0 VRHE) under one sun illumination (AM 1.5G, 100 mW cm-2), which is 40% higher than that of the reference device based on TiO2/QD (T/Q) photoanodes. This is attributed to a synergistic effect of the promising optoelectronic properties of the colloidal heterostructured QDs and improved electron transport (reduced charge transfer resistance) within the TiO2-MWCNT hybrid anodes enabled by the directional path of MWCNTs for the photo-injected electrons towards FTO. Furthermore, the PEC device based on the T/Q-M hybrid photoanode is more stable (∼19% loss of its initial photocurrent density) when compared with the T/Q photoanode (∼35% loss) after two hours of continuous one sun illumination. Our results provide fundamental insights and a different approach to improve the efficiency and long-term stability of PEC devices and represent an essential step towards the commercialization of this emerging solar-to-fuel conversion technology.

A programmable microscopic stage: Design and development.

Microscopes have become a significant part of pathological study. Currently, motorized microscopes are enabled with horizontal and vertical movements, with the facility of fast response in acquiring images or videos from the slide. During microbial screening, viewing the specimen needs following a directional path viz., zig-zag, inward spiral, meander, and so forth. Even though the motorized movements are built-in, human intervention is required while screening. This leads to time delay in the scanning process and may leave some portions of the specimen unattended. In this proposed system, a programmable framework to define the scanning direction for the specimen and a firmware to control the microscopic stage is implemented, to enable customization of the scanning pattern without any human intervention during complete course of screening. The user can define the customized scanning pattern using two-dimensional (2D) graphics drawing primitives. The final drawing is converted into preparatory codes through a micro-computer numeric controlled software, which extracts the address information relating to the movement and direction of the stage. These X, Y directional information are fed into the machine control unit for activating the linear driving system, which has servo drives and motors to power the spindle for precise microscopic stage movement. The proposed system is cost effective and reduces the reliance on technicians in examining the whole slide. The system is also portable and can be attached to any conventional or fluorescence microscope. Some pre-defined scanning patterns have been tested for the stage movements and validated in this work.

Fully automated extraction of coronary main branches based on directional minimal path

Fully automated extraction of coronary main branches based on directional minimal path

Channel Characterization and Path Loss Modeling in Indoor Environment at 4.5, 28, and 38 GHz for 5G Cellular Networks

The current propagation models used for frequency bands less than 6 GHz are not appropriate and cannot be applied for path loss modeling and channel characteristics for frequency bands above 6 GHz millimeter wave (mmWave) bands, due to the difference of signal propagation characteristics between existing frequency bands and mmWave frequency bands. Thus, extensive studies on channel characterization and path loss modeling are required to develop a general and appropriate channel model that can be suitable for a wide range of mmWave frequency bands in its modeling parameter. This paper presents a study of well-known channel models for an indoor environment on the 4.5, 28, and 38 GHz frequency bands. A new path loss model is proposed for the 28 GHz and 38 GHz frequency bands. Measurements for the indoor line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios were taken every meter over a separation distance of 23 m between the TX and RX antenna locations to compare the well-known and the new large-scale generic path loss models. This measurement was conducted in a new wireless communication center WCC block P15a at Universiti Teknologi Malaysia UTM Johor, Malaysia, and the results were analyzed based on the well-known and proposed path loss models for single-frequency and multifrequency models and for directional and omnidirectional path loss models. Results show that the large-scale path loss over distance could be modeled better with good accuracy by using the simple proposed model with one parameter path loss exponent PLE (n) that is physically based to the transmitter power, rather than using the well-known models that have no physical base to the transmitted power, more complications (require more parameters), and lack of anticipation when explaining model parameters. The PLE values for the LOS scenario were 0.92, 0.90, and 1.07 for the V-V, V-H, and V-Omni antenna polarizations, respectively, at the 28 GHz frequency and were 2.30, 2.24, and 2.40 for the V-V, V-H, and V-Omni antenna polarizations, respectively, at the 38 GHz frequency.