Point Placement Research Articles

Optimized Pilot Point Emplacement Based Groundwater Flow Calibration Method for Heterogeneous Small-Scale Area

Groundwater flow modeling in a small-scale area requires practical techniques to obtain high accuracy results. The effectiveness of the model calibration is the most challenging for simulating the hydraulic head. In pursuit of this, we proposed an optimized groundwater flow calibration method based on the pilot point emplacement technique for a 3D small-scale area in this work. Subsequently, two emplacement structures were tested during the experimentation, the regular pilot point placement, and the middle head measurement down gradient (MHMDG) placement with two different densities. The parameter estimation (PEST) numerical code applying the kriging interpolation was used to estimate the hydraulic conductivity field by MODFLOW. Moreover, geological SGrid models were chosen for the conceptual model. Thirty-seven observation wells were used for experimental simulations to test the proposed method in a heterogeneous confined aquifer. The result shows that the small-scale modeling was complicated, and the studying area presented a significant heterogeneity in horizontal hydraulic conductivity. The middle head measurement down gradient (MHMDG) pilot point case with the larger density gave the best R-squared 0.901 and minimum residual error of 0.0053 m compared to 0.880 and 0.078 m, respectively, for the regular placement. The calibration accuracy depended on the frequency and the emplacement of the pilot point. Therefore, the initial value should be technically selected to minimize the computation burden. The proposed techniques help to improve the groundwater flow model calibration based on the pilot point methodology for groundwater resources management.

Study on the Relationship Between VR Sickness and Trajectory of Fixation Point Using HMD

It has been reported that VR sickness can be suppressed by the placement of a fixation point in a field of view. However, the relationship between trajectory of the fixation point and VR sickness reduction effect is not made clear. Therefore, it is attempted that relationship is investigated using HMD in this study.

The Dance Company Film

The Dance Company Film

Efficacy of botulinum toxin in masseter muscle hypertrophy for lower face contouring.

Masseter muscle hypertrophy (MMH) usually presents with cosmetic concerns as it may lead to widening of the lower face. Apart from the traditional surgical approaches, botulinum toxin type A (BTA) injection is a non-invasive treatment option available. There are no standard guidelines for this procedure. To study the efficacy of botulinumtoxin A in MMH for lower face contouring. The Cochrane Library, PubMed/MEDLINE, Google-scholar, Science-Direct database, and ResearchGate from inception until September 2021 were searched using the keywords "botulinumtoxin type A," "masseter muscle hypertrophy," "lower face contouring," and "masseter botox." All available retrospective and prospective studies, case-series, case-reports, and expert reviews were included with an emphasis on efficacy of BTA in MMH and units injected into the muscle, points of placement, adverse events, and the duration of its effect. Reference lists of the resultant articles, as well as relevant reviews, were also searched. 40 articles were shortlisted for the review, of which 14studies with sample-size ≥10 in accordance with the study requirements were summarized in a tabular form for analysis and easy comparison and reference. BTA injection is a non-invasive, safe, and effective treatment for MMH. The optimum number of BTA units could not be ascertained due to wide variability in the studies as well as ethnicity of patients and extent or some measurement of MMH. The points of placement of injection should be well within the boundaries of the masseter muscle. The maximum effect of BTA after a single injection session is usually seen in ~3months, and the duration may last for 6-12months. Multiple injection sessions may be required to maintain a long-term effect. Injection technique and total number of injection units of neuromodulator must be individualized for each patient.

Parallel domain discretization algorithm for RBF-FD and other meshless numerical methods for solving PDEs

In this paper, we present a novel parallel dimension-independent node positioning algorithm that is capable of generating nodes with variable density, suitable for meshless numerical analysis. A very efficient sequential algorithm based on Poisson disc sampling is parallelized for use on shared-memory computers, such as the modern workstations with multi-core processors. The parallel algorithm uses a global spatial indexing method with its data divided into two levels, which allows for an efficient multi-threaded implementation. The addition of bootstrapping enables the algorithm to use any number of parallel threads while remaining as general as its sequential variant. We demonstrate the algorithm performance on six complex 2- and 3-dimensional domains, which are either of non rectangular shape or have varying nodal spacing or both. We perform a run-time analysis of the algorithm, to demonstrate its ability to reach high speedups regardless of the domain and to show how well it scales on the experimental hardware with 16 processor cores. We also analyse the algorithm in terms of the effects of domain shape, quality of point placement, and various parallelization overheads.

Initial state estimation from limited observations of the heat equation in metric graphs

This paper deals with initial state estimation problems of the heat equation in equilateral metric graphs being admitted to have cycles. Particularly, we are concerned with suitable placements of observation points in order to uniquely determine the initial state from observation data. We give a necessary and sufficient condition for suitable placements of observation points, and such suitable placements are determined from transition matrices of metric graphs. From numerical simulations, we confirm effectiveness of a necessary and sufficient condition.

The Mechanisms Underlying Vertical Artifacts in Lung Ultrasound and Their Proper Utilization for the Evaluation of Cardiogenic Pulmonary Edema.

The recent advances in lung ultrasound for the diagnosis of cardiogenic pulmonary edema are outstanding; however, the mechanism of vertical artifacts known as B-lines used for the diagnosis has not yet been fully elucidated. The theory of “acoustic trap” is useful when considering the generation of vertical artifacts. Basic research in several studies supports the theory. Published studies with pilot experiments indicate that clarification of the relationship between the length and intensity of vertical artifacts and physical or acoustic composition of sources may be useful for differentiating cardiogenic pulmonary edema from lung diseases. There is no international consensus with regard to the optimal settings of ultrasound machines even though their contribution to the configuration of vertical artifacts is evident. In the clinical setting, the configuration is detrimentally affected by the use of spatial compound imaging, the placement of the focal point at a deep level, and the use of multiple focus. Simple educational materials using a glass microscope slide also show the non-negligible impact of the ultrasound machine settings on the morphology of vertical artifacts.

SPARSE CELLULAR RADIO NETWORK

The wireless telecommunications environment is characterized by high variation in signal strength, and architectural constraints are imposed on the placement of radio access points. As an extreme case, it can be assumed that the location of the radio access points in such systems is arbitrary. Such radio systems are proposed to be called sparse cellular radio networks. This term is proposed by analogy with the well-known definition of a sparse array from the field of programming.

Optimal Test Point Placement Based on Fault Diagnosability Quantitative Evaluation

The optimal test point placement problem in existing research results is mainly limited to the qualitative study of whether faults can be diagnosed without considering the difficulty of diagnosing faults. We proposed an optimal test point placement approach based on fault diagnosability quantitative evaluation to solve the above problem. First, the fault diagnosability is quantitatively evaluated based on the maximum mean discrepancy (MMD). Then, the problem of optimal test point placement is considered a multi objective optimization problem. The optimal test point set is solved using the multi objective sparrow search algorithm (MOSSA) based on the fault diagnosability quantitative evaluation results, considering limitations on the test point number, reliability, and cost. Finally, the proposed approach is used to optimize the placement of test points in the switching power supply system. The simulation results show that only three test points need to be placed to make the system meet the fault diagnosability requirements. Two test point placement schemes are obtained, which can be selected according to different practical requirements. The experimental results illustrate that the proposed approach can optimize the system test point placement while ensuring good fault diagnosability.

Impact of Wi-Fi network coverage planning on the logistics objects’ location accuracy

The use of Wi-Fi networks to construct a system for determining the object’s location inside warehouses is the simplest and most cost-effective way of solving the logistical problems. The positioning in such a system is based on measuring the received signal strength level with the application of the lateration (trilateration) method to calculate the target’s coordinates. This method requires taking into account the electromagnetic environment in the room and the fulfillment of certain requirements for the construction of a network serving as a positioning tool. Incorrect access points placement in the premises leads to a significant positioning error, unacceptable in most cases of the system’s application. The article isdevoted to the improvement of the positioning accuracy by the network structure correction in accordance with the coverage and frequency planning. To implement the lateration algorithm for the determination of the distances between a mobile object and an access point, three radio wave propagation models were used, selected from a variety of similar models after the preliminary analytical and experimental studies. The power loss coefficients used in the models for the signal’s passing through partitions and floors were adapted to the configuration and features of the rooms in which the experiments were conducted.

Investigation of the relationship between the levels of public trust and corruption: A topological model and statistical methods

The article analyzes the concepts of "trust" and "corruption of society" and explores the interdependence between them using the international indexes Edelman Trust Barometer (ETB) and Corruption Perceptions Index (CPI). The research methods are: 1) the topological model proposed by the authors, based on the averaged values of these indices; 2) correlation and regression analysis; 3) interval method (studying the dependence on the selected intervals of the averaged values of ETB and CPI). The topological model uses data on the values of these indices for 28 countries and was developed in two versions for the time periods (2011–2021) and (2013–2019). In both cases, the model gives a similar picture of the points placement on the coordinate plane, which indicates the stability of the results. A comparison of empirical data over the time periods revealed countries with a relatively stable ratio of ETB and CPI indices (Germany, Indonesia, Canada, Colombia, France) and countries where this ratio is noticeably changing (Australia, Argentina, Brazil, Hong Kong, Italy, the Netherlands). The analysis of the topological model was carried out and zones of low, medium and high levels of corruption were identified. Zones are characterized by a specific type of relationship between ETB and CPI indices. The general type of dependence of the level of trust on corruption in the form of a horizontal S-shaped curve is approximately determined. Regression analysis using time series data for 28 countries was performed. Statistically significant linear regression equations (reflecting the relationship between the considered economic categories) were obtained for some countries (the Netherland, Sweden and Japan). The conclusion about the significant nonlinearity of the studied relationship is made. This is evidenced by both the visual analysis of the topological model and the results of regression analysis conducted for the selected intervals of change values of the ETB and CPI indexes.

Data Aggregation Point Placement for Smart Meters in the Smart Grid

Smart meters (SMs) measure and transmit fine-grained electricity consumption data to the data center at a certain high frequency (such as every 15 minutes). A data aggregation point (DAP) is a relay device between a cluster of SMs and data centers. The placement of DAPs significantly impacts the cost-effectiveness and quality of service (QoS) of the communication system. Nowadays, many newly installed SMs not only can send data to the DAPs but also receive/send data from/to other SMs. This paper proposes a novel approach for the optimal DAP placement in a multi-hop routing scenario, where SMs can serve as small relay devices so that communications among SMs can be leveraged to reduce the overall communication cost. To do so, we formulate a mixed-integer optimization problem that minimizes three types of cost: installation, transmission, and delay cost. Since the optimization problem involves too many binary variables to be efficiently solved to optimality, a heuristic approach is developed to obtain a desirable solution with a low computational burden. The heuristic iteratively implements clustering approximation, pole assignment, and optimal routing until convergence of the total cost value. Both an illustrative example and case studies verify the effectiveness of the proposed method.

Access Point Placement Model for Indoor Environment using Hybrid Empirical Propagation and Simulated Annealing Algorithm

Access Point Placement Model for Indoor Environment using Hybrid Empirical Propagation and Simulated Annealing Algorithm

Point placement of late vegetative stage nitrogen splits increase the productivity, N-use efficiency and profitability of tropical maize under decade long conservation agriculture

The rising economic and environmental costs of mineral fertilizers associated with lower nutrient use efficiency, and the need to respond the limitations of N fertilization under residue retained condition of conservation agriculture (CA) motivate the research for alternative N placement methods. The third principle of CA, i.e., residue retention on the soil surface hinders the right placement of split applied nitrogen (N). To address this issue, we assessed the impact of three N placement methods, i.e., NPM1: both the N splits were surface band placed, NPM2: the first split of N was sub-surface point placed and second N split (late vegetative stage) was surface band applied, and NPM3: both the N splits were sub-surface point placed, under 4-long-term tillage and residue management (+R) options, i.e., permanent raised bed (PB+R), zero-till flat (ZT+R) conventional till flat (CT+R) and first time zero till flat sowing of the crop on last 10-year fallow land (FZT+R), in an on-going long-term study (since 2008) in maize for three consecutive years (2018–2020). Results showed that sub-surface point placement of both the N splits (NPM3) increased maize grain yield by 4.7, 7.0 and 6.0% (3-years mean basis) compared to NPM2, under CA-based PB, ZT, and FZT plots, respectively. The peak growth rate in the CA-based PB+R plot was advanced by 4-days with a 9.2% higher growth rate compared to CT+R. Similarly, the peak growth rate in NPM3 was 20% higher than NPM1 plots. The changes in soil properties under CA altered the crop growth behavior, while sub-surface point placement of split applied nitrogen (N) increased the grain N content and altered the peak growth rate of maize. The variability in maize grain yield was best described by cob length and number of cobs in long-term tillage and by cob length in N management plots. The cob length and grains per cob were increased by 4.8–8.7 and 8.6–12.8% under CA-based plots compared to CT+R, respectively. The amount of vegetative stage accumulated N remobilized to maize grain was 21.2% higher under PB+R compared to CT+R plots, while the N remobilization in NPM3 was 22.9% higher compared to NPM1 plots. Similarly, the contribution of reproductive stage N uptake to grain was 9–12% higher in CA-NPM3 compared to CT-NPM1 plots. Further, the early and vigorous growth of maize resulted in a higher accumulation of N and its remobilization to the grains in CA-based and N point placed plots. The sub-surface point placement of N (NPM3) resulted in a 12.8, 14.5 and 9.2% higher benefit-cost ratio compared to NPM1 plots in 11th (2018), 12th (2019) and 13th (2020) years of experimentation, respectively. Therefore, the present study visualizes the impact of a decade-long CA and efficient N management on crop growth behavior, N uptake and remobilization and crop productivity and water use efficiency. This study provides evidence to popularize this technology in the CA-systems of Indo-Gangetic Plains and other similar agro-ecologies.

Point placement method in the plane taking into account points mutual reachability

The paper presents an approach for determining the positions of a set of points that provide a given ratio of mutual reachability for a given point set on the plane. The presented method consists in drawing circles with centers at given points of the set on a regular grid and determining the intersection points of the maximum number of circles. The proposed method is implemented in the form of a software tool that allows you to find the minimum required set of points on a regular grid, which covers a given set, and also allows you to visualize the results. Figs.: 3. Refs.: 13 titles.

Improved stratified sampling strategy for estimating mean soil moisture based on auxiliary variable spatial autocorrelation

Soil moisture is crucial in governing land surface processes that have an important influence on the yield and quality of crops. Therefore, it is essential to establish criteria for appropriate mean soil moisture monitoring strategy in order to obtain a representative mean soil moisture value of a farmer’s field. In this study, the plant available water capacity was introduced as an auxiliary variable and a stratified soil moisture sampling method based on the spatial autocorrelation of auxiliary variables (SSAV) was proposed by integrating classical statistics and geostatistics. The results of the proposed methods were compared with those of the international common simple random sampling (SRS) and stratified random sampling (STRS) methods at the field and regional scale. The results showed that the range of mean relative error and the standard deviation of the soil moisture obtained with the SSAV method were significantly lower than those of the soil moisture obtained with the SRS and STRS methods at both the field and regional scales. The root mean squared error between the observed and estimated soil moisture at the field and regional scales were found to be 0.0104 and 0.0125 cm3/cm3, respectively, with the SSAV method, which are significantly lower than those obtained with the SRS method (0.0124 and 0.0139 cm3/cm3, respectively) and STRS method (0.0116 and 0.0130 cm3/cm3, respectively). The standard deviation of the relative difference, mean absolute bias error, and root-mean-squared difference of the SSAV method, which were used as stability indices of the monitoring points, were all lower than those of the SRS and STRS methods. These results demonstrated that the SSAV could promote the monitoring accuracy and precision, and the soil moisture estimated based on the SSAV could represent the mean soil moisture for several years. The use of the SSAV is recommended as an effective method for the placement of soil moisture sampling points to estimate the mean soil moisture.

Deep Directional Electromagnetic Technique Improves Well-Drilling Efficiency

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 202265, “Leap of Faith From Conventional to EM Look-Ahead: A Game-Changing Technology To Improve Well Efficiency,” by Muhamad Yanuar Mahardi, Hendarsyah Hendarsyah, and Kharisma Endarmoyo, PT Pertamina, et al., prepared for the 2020 SPE Asia Pacific Oil and Gas Conference and Exhibition, originally scheduled to be held in Perth, Australia, 20–22 October. The paper has not been peer reviewed. The structure in the Matindok block in Central Sulawesi operated by Pertamina has proven producible gas reserves in the Minahaki formation. One of the main challenges in this area is the low resolution of seismic data, leading to a high depth uncertainty. The complete paper describes a technology developed to meet these challenges with the capability to map and detect lithology changes ahead of the bit in real time. Geological Background A first exploration well, PEP-001, was drilled in 2018. The structure has a Miocene carbonate buildup play, and the target reservoir is the M pinnacle carbonate reef. The PEP-001 well was planned to set the 9⅝-in. casing point above the top of the M formation. Offset wells did not show any clear markers in the thick shale above the M formation that could have been used for log correlation. In previously drilled offset wells, correlation was performed convention-ally by examination of cutting samples and on drilling breaks. However, when Well PEP-001 was drilled, no apparent drilling break was observed. By the time cuttings reached the surface, the bit had drilled into 20 m of the M formation. Because the casing covered most of the upper carbonate formation, openhole logging and well-testing data were not acquired to delineate the target formation optimally. The second exploration well, PEP-002, was planned with an objective of setting 9⅝-in. casing approximately 5 m above the top of M to acquire full-interval coverage of coring, openhole wireline logging, and well testing. This information was critical for optimal reservoir delineation to allow for accurate reserves calculation and future development. Conventional correlation methods have proven insufficient for casing point placement. The presence of limestone stringers in offset wells within proximity of the top of M presented an additional challenge. The stringers could have been misinterpreted as the main carbonate body, if interpretation were based solely on cutting samples. Real-Time Electromagnetic (EM) Look-Ahead Technology

WI-FI Access Point (WAP) OPTIMAL Placement in an Indoor Location

Abstract: The popularity of location based applications is undiminished today. They require accurate location information which is a challenging issue in indoor environments. Wireless technologies can help derive indoor positioning data. Especially, the WiFi technology is a promising candidate due to the existing and almost ubiquitous Wi-Fi infrastructure. The already deployed WiFi devices can also serve as reference points for localization eliminating the cost of setting up a dedicated system. However, the primary purpose of these Wi-Fi systems is data communication and not providing location services. This accuracy can be increased by carefully placing the Wi-Fi access points to cover the given territory properly. This method is based on simulated annealing which finds the optimal number and placement of Wi-Fi access points with regard to indoor positioning and investigate its performance in a real environment scenario via simulations. Keywords: Wi-fi access point (WAP), simulated annealing, router, wireless, placement, locationing.

Referencing for intraoperative navigation: Evaluation of human bias

Navigation-assisted surgery is the gold standard for complex reconstructive procedures of the midface and facial skeleton, and artificial and anatomical landmarks are often used for reference. The correct identification of these landmarks before surgery is crucial for the accuracy of the navigation system. This study aimed to investigate the human errors in reference point placement. This retrospective study investigated 228 reference-point positions in 51 cases where navigation was utilized. The discrepancies between the actual reference point-position and manually planned preoperative reference points were quantified using Brainlab iPlanCMF 3.0.6. The referencing methods used in these cases included dental registration splints, osteosynthesis materials, anatomical landmarks, and combinations of these methods. The average discrepancy in the actual and manually planned reference points was 0.29 ± 0.41 mm. The use of anatomical landmarks demonstrated a significantly lower deviation (p < 0.05), although the differences between the errors in reference-point placement using dental registration splints, osteosynthesis materials, or combinations of these methods were not statistically significant. The frequency of misplacement of reference points was significantly higher than expected. These errors might have been caused by human bias during manual placement of the points or intraoperative difficulties caused by extensive metal artifacts. Thus, we postulate that the surgical personnel involved in planning navigation-assisted surgery should undergo intensive training. The development of new referencing methods that are less susceptible to these causes of error might help overcome human bias.

Optimal spatial sampling design for monitoring potentially toxic elements pollution on urban green space soil: A spatial simulated annealing and k-means integrated approach

Sampling design in soil science is critical because the lack of reliable methods and collecting samples requires tremendous work and resources. The aims were to obtain an optimal sampling design for assessing potentially toxic elements pollution using pilot Pb soil samples from the urban green space area of Shanghai, China. Two general steps have been used. The first step is to determine the optimum sample size against improving the prediction accuracy and monitoring costs using the spatial simulated annealing (SSA) algorithm. Secondly, we evaluated their likely placement of new extra sampling points by integrated SSA with k-means (SSA+ k-means) and expert-based (SSA+ expert-based) sampling methods. The improvement of sampling design by the integrated sampling approaches was evaluated using mean kriging variance (MKV), root mean square error (RMSE), and mean absolute percentage error (MAPE). The findings indicated that adding and placing 350 new monitoring points upon the existing sampling design by SSA increased the prediction accuracy by 64.35%. The MKV for the optimized SSA+ k-means sample was lower than by 4.12 mg/kg, 9.46 mg/kg compared with locations optimized by SSA and SSA+ expert-based method, respectively. Optimizing new sampling locations by SSA+ k-means sampling method was reduced MAPE by 9.26% and RMSE by 7.13 mg/kg compared to optimizing by SSA alone. However, there was no improvement in placing the new sampling points in SSA+ expert-based sampling method; instead, it increased the error by 8.11%. This paper shows integrating optimization approaches to evaluate the existing sampling design and optimize a new optimal sampling design.