Resolution Capacity Research Articles

Detection of Cavity Using Electrical Resistivity Tomography (ERT) at Patherdih, Jharia Coal Field, Dhanbad, India

Geophysical survey for cavity detection is one of the most common near surface application. The usage of resistivity methods are also very straightforward for the air filled underground voids, which should have theoretically very high resistivity in the ERT image, whereas the water filled cavities have low resistivity in Electrical Resistivity Tomography (ERT) image. Three different geoelectric arrays Wenner, Schlumberger and Dipole-dipole are applied for detecting cavities. The survey results suggest that ERT is a viable geophysical tool for the detection and monitoring of mining voids and other subsurface cavities. The resolution capacity of joint Wenner-Schlumberger, Dipole-dipole array for the detection of cavity is greater than that of the individual one. Using the ERT survey in Patherdih Thana Basti village (Jharia coal field), a number of air filled cavity or water filled mining voids are detected at around 25-30m of below the ground level at different profile distance of 630m profile length along the road that extending S-E to N-W direction.

Development of signal converter of thermal sensors based on combination of thermal and capacity research methods

The problem of functional integration of thermal and capacity research methods, which provides the possibility of realizing a new generation of analog front­end of the Internet of Things in the areas of materials science, biophysics and medicine, is solved. Functional integration means the possibility of the use of the same structure for its controlled heating and temperature measurement. For this purpose, instead of discrete resistive heaters and temperature sensors, transistor structures are proposed. This helps to minimize the sizes of measurement transducers, and so the spatial resolution of the transducers­based sensors of thermal analysis. The concept of constructing the functionally integrated thermal sensors based on the transistor structures and capacitive signal transducers is developed. The novelty of the proposed sensors of thermal analysis, in addition to measurement of temperature and amount of thermo­energy emitted and absorbed in the object of research, is the possibility of measuring the electrical capacity. This possibility could be particularly assured by the measurement of temperature deformation of a research object or a console that is bent under the effect of the object. The new solution of the control scheme of the transistor transformers that support the pulse managed heating and forming the informative signal of the temperature of transistor is proposed. The high precision Analog Devices AD7747 24­bit converter is taken as the basis of the capacitive signal transducer.The developed transducer provides the managed heating of research objects and is characterized by the high values of temperature resolution (not worse than 0.01 oC) and electrical capacity (not worse than 10–16 aF) measurement.

Estrategias heurísticas para incrementar la capacidad de resolución de problemas en estudiantes de educación secundaria

Estrategias heurísticas para incrementar la capacidad de resolución de problemas en estudiantes de educación secundaria

Characterization of secondary metabolites from green cocoa beans using focusing-modulated comprehensive two-dimensional liquid chromatography coupled to tandem mass spectrometry

Proanthocyanidins as well as other secondary metabolites present in green cocoa beans were studied thanks to a new method involving the use of on-line comprehensive two-dimensional liquid chromatography coupled to tandem mass spectrometry (LC × LC-MS/MS). In order to enhance the performance of previously developed methodologies, the use of different modulation strategies were explored. Focusing modulation clearly allowed the attainment of higher resolving power and peak capacity compared to non-focusing modulation set-ups. Moreover, the use of active modulation by the addition of a make-up flow efficiently helped to compensate for the solvent strength mismatch produced between dimensions. The optimized method was useful to successfully describe the secondary metabolite composition of green cocoa that was characterized by the presence of 30 main compounds, including 3 xanthines, 2 flavan-3-ols and 24 oligomeric procyanidins with a degree of polymerization up to 12. The obtained results showed that the proanthocyanidins found in the cocoa beans were exclusively B-type procyanidins. The existence of (epi)catechin subunits linked to sugar or galloyl moieties was not observed. The developed method produced a good separation of secondary metabolites allowing an improvement with respect to the available methodologies for the analysis of a complex food sample such as cocoa metabolites in terms of speed of analysis, resolution and peak capacity.

Satisfaction with family relations and support according to elderly persons caring for elderly relatives

Abstract Objective: The aim of the presentstudy was to investigate the associations between the satisfaction of family caregivers and family relations; sociodemographic variables; the type and direction, sufficiency and burden of family support, and the number of social partners involved. Method: A total of 148 caregivers of elderly relatives who were physically and cognitively dependent were recruited from medical clinics and home care services in cities in the state of São Paulo and invited to respond to a questionnaire about family support, and to a scale of satisfaction with family relationships with reference to adaptation, partnership, growth, affection and resolutive capacity. The chi-squared and Fisher's exact tests were used to compare frequencies for the scores of the two satisfaction levels (low and intermediate, and high). To analyze the relationship between high levels of satisfaction and other variables, univariate and hierarchical logistic regression analysis was used. Results: High levels of satisfaction were related to the reciprocity and suffiency of received emotional support, and absence of burden associated to giving support. The adequacy of emotional support was most strongly associated with high levels of satisfaction with family relationships. Conclusion: For the satisfaction of caregivers of elderly persons with family functioning, quality of support is better than quantity, reciprocity is more important than unidirectionality and emotional is the most important type of support.

Legal Engineering on the Blockchain: ‘Smart Contracts’ as Legal Conduct

A new legal field is emerging around blockchain platforms and automated transactions. Understanding the relationships between law, legal enforcement, and these technological systems has become critical for scaling blockchain applications. Because ‘smart contracts’ do not themselves constitute agreements, the first necessary ‘legal’ development for transacting with these technologies involves linking computational transactions to natural language contracts. Various groups have accordingly begun building libraries of machine readable transaction modules that correspond to natural language contracting elements. In doing so, they are creating the building blocks for ever more complex transactions that will ultimately define the entire envelope of computational legal conduct in these environments, and likely standardise the field. However, also critical to emerging blockchain ‘legalities’, is the capacity for dispute resolution and legal enforcement. Beyond the performance of parties, or the quality of goods and services transacted, new mechanisms are also needed to address the performance of the computational transaction systems themselves. Such mechanisms are necessary to address the reality that smart contracts cannot be forced to perform actions beyond the parameters of their coding, even by a judicial order. Legal tools, both technological and institutional, are thus being developed to ‘soften’ the effects of self-executing transactions. In this article we treat these developments as law-making practices that are constitutive of an emerging legal field. Legal engineering exercises of this kind are not novel, and by drawing on historic examples from the common law and international arbitration, we gain insights into the competitive dynamics likely to be shaping legal engagements on the blockchain.

What We Know About the Brain Structure-Function Relationship.

How the human brain works is still a question, as is its implication with brain architecture: the non-trivial structure–function relationship. The main hypothesis is that the anatomic architecture conditions, but does not determine, the neural network dynamic. The functional connectivity cannot be explained only considering the anatomical substrate. This involves complex and controversial aspects of the neuroscience field and that the methods and methodologies to obtain structural and functional connectivity are not always rigorously applied. The goal of the present article is to discuss about the progress made to elucidate the structure–function relationship of the Central Nervous System, particularly at the brain level, based on results from human and animal studies. The current novel systems and neuroimaging techniques with high resolutive physio-structural capacity have brought about the development of an integral framework of different structural and morphometric tools such as image processing, computational modeling and graph theory. Different laboratories have contributed with in vivo, in vitro and computational/mathematical models to study the intrinsic neural activity patterns based on anatomical connections. We conclude that multi-modal techniques of neuroimaging are required such as an improvement on methodologies for obtaining structural and functional connectivity. Even though simulations of the intrinsic neural activity based on anatomical connectivity can reproduce much of the observed patterns of empirical functional connectivity, future models should be multifactorial to elucidate multi-scale relationships and to infer disorder mechanisms.

Natural deep eutectic solvents as the major mobile phase components in high-performance liquid chromatography-searching for alternatives to organic solvents.

Over the past six decades, acetonitrile (ACN) has been the most employed organic modifier in reversed-phase high-performance liquid chromatography (RP-HPLC), followed by methanol (MeOH). However, from the growing environmental awareness that leads to the emergence of "green analytical chemistry," new research has emerged that includes finding replacements to problematic ACN because of its low sustainability. Deep eutectic solvents (DES) can be produced from an almost infinite possible combinations of compounds, while being a "greener" alternative to organic solvents in HPLC, especially those prepared from natural compounds called natural DES (NADES). In this work, the use of three NADES as the main organic component in RP-HPLC, rather than simply an additive, was explored and compared to the common organic solvents ACN and MeOH but additionally to the greener ethanol for separating two different mixtures of compounds, one demonstrating the elution of compounds with increasing hydrophobicity and the other comparing molecules of different functionality and molar mass. To utilize NADES as an organic modifier and overcome their high viscosity monolithic columns, temperatures at 50°C and 5% ethanol in the mobile phase were used. NADES are shown to give chromatographic performances in between those observed for ACN and MeOH when eluotropic strength, resolution, and peak capacity were taken into consideration, while being less environmentally impactful as shown by the HPLC-Environmental Assessment Tool (HPLC-EAT) metric. With the development of proper technologies, DES could open a new class of mobile phases increasing the possibilities of new separation selectivities while reducing the environmental impact of HPLC analyses. Graphical abstract Natural deep eutectic solvents versus traditional solvents in HPLC.

Sequential Hybrid Three-Dimensional Gas Chromatography with Accurate Mass Spectrometry: A Novel Tool for High-Resolution Characterization of Multicomponent Samples

A novel sequential three-dimensional gas chromatography-high-resolution time-of-flight mass spectrometry (3D GC-accTOFMS) approach for profiling secondary metabolites in complex plant extracts is described. This integrated system incorporates a nonpolar first-dimension (1Dnp) separation step, prior to a microfluidic heart-cut (H/C) of a targeted region(s) to a cryogenic trapping device, directly followed by the rapid reinjection of a trapped solute into a polar second-dimension (2DPEG) column for multidimensional separation (GCnp-GCPEG). For additional separation, the effluent from 2DPEG can then be modulated according to a comprehensive 2D GC process (GC×GC), using an ionic liquid phase as a third-dimension (3DIL) column, to produce a sequential GCnp-GCPEG×GCIL separation. Thus, the unresolved or poorly resolved components, or regions that require further separation, can be precisely selected and rapidly transferred for additional separation on 2D or 3D columns, based on the greater separation realized by these steps. The described integrated system can be used in a number of modes, but one useful approach is to target specific classes of compounds for improved resolution. This is demonstrated through the separation and detection of the oxygenated sesquiterpenes in hop ( Humulus lupulus L.) essential oil and agarwood ( Aquilaria malaccensis) oleoresin. Improved resolution and peak capacity were illustrated through the progressive comparison of the tentatively identified components for GCnp-GCPEG and GCnp-GCPEG×GCIL methods. Relative standard deviations of intraday retentions (1 tR, 2 tR,, and 3 tR) and peak areas of ≤0.01, 0.07, 0.71, and 7.5% were achieved. This analytical approach comprising three GC column selectivities, hyphenated with high-resolution TOFMS detection, should be a valuable adjunct for the improved characterization of complex plant samples, particularly in the area of plant metabolomics.

The potential for RGB images obtained using unmanned aerial vehicle to assess and predict yield in sugarcane fields

ABSTRACTEstimating yield is a major challenge for the majority of agricultural crops. With the advancement of field technologies however, especially those related to the use of Unmanned Aerial Vehicles (UAV) or Drones, the quality of available information has increased, making it possible to overcome technological bottlenecks. However, drone technologies have advanced much faster than studies dealing with the treatment and analysis of information, which can represent an obstacle to the complete adoption of such technologies in sugarcane fields. The objective of the present study was to evaluate the potential for UAV images to assess the degree of canopy closure from different planting approaches and row-spacing treatments applied to sugarcane crop, in order to assess the potential of these tools to predict crop yield. The vegetative growth of the crop was evaluated and the images were obtained at the point of maximum tillering and the inflection point of the biomass accumulation curve. The evaluations included the index; LAI (Leaf Area Index) and GRVI (Green-Red Vegetation Index) obtained by field sensor and UAV, respectively. Because the images from UAV cover the total area, the results revealed that GRVI appears to be much better able to reflect the whole condition of the crop yield (R2 = 0.69) in the field when compared to LAI (R2 = 0.34); demonstrated convincingly by the high spatial resolution capacity of the technology. When integrated, these two indices were able to improve yield estimates by 10% (R2 = 0.79). Images obtained using UAV can represent a low-cost tool for obtaining high-precision remote data that can be used to estimate the agricultural yield of sugarcane fields; and in this way are an effective tool to aid decision making by growers.

Vision‐Based Fatigue Crack Detection of Steel Structures Using Video Feature Tracking

AbstractFatigue cracks developed under repetitive loads are one of the major threats to structural integrity of steel bridges. Human inspection is the most commonly applied approach for fatigue crack detection, but is time consuming, labor intensive, and lacks reliability. In this study, we propose a computer vision‐based fatigue crack detection approach using a short video stream taken by a consumer‐grade digital camera. A feature tracking technology is applied to the video for tracking the surface motion of the monitored structure under repetitive load. Then, a crack detection and localization algorithm is established to effectively search differential features at different video frames caused by the crack opening and closing. The effectiveness of the proposed approach is validated through testing two experimental specimens with in‐plane and out‐of‐plane fatigue cracks, respectively. Results indicate that the proposed approach can robustly identify the fatigue crack, even when the crack is under ambient lighting conditions, surrounded by other crack‐like edges, covered by complex surface textures, or invisible to human eyes due to crack closure. Furthermore, our proposed approach enables accurate quantification of the crack opening under fatigue loading with submillimeter accuracy. However, due to the capacity of the camera resolution in this study, accurate detection of crack tip remains challenging.

Sensitivity Analysis of Conflict-Free Resolutions for the Airborne Cluster–Ecosystem

To support the future automation of air traffic management, this study examines a decrement in the number of feasible, conflict-free avoidance maneuvers within a tactical air traffic system, relying on the concept of an airborne ecosystem. An ecosystem represents a set of aircraft with the trajectory-amendment, decision-making capability, whose trajectories are identified inside a computed airspace volume and causally involved in a safety event that is predicted for a certain look-ahead time from their current positions. The concept is based on the predicted conflict between two aircraft, whose trajectory segments are used for detection of the surrounding aircraft by identification of the spatiotemporal interdependencies. The potential resolution capacity is characterized by a decreasing rate of the feasible solutions over time, while the aircraft are flying toward the closest point of approach. Causal analysis was performed via the initialization of different cluster–ecosystem transitions with the goal of measuring the scenarios complexity in terms of the time-based conflict-free solutions, in front of the elapsed time to the aircraft collision. Simulation of eight ecosystems generated from two pairwise conflicts with different avoidance capacities illustrates a potential of negotiation as the aircraft tendency to reach a resolution agreement via early or late decisions.

Chronic nasal dysfunction

Chronic nasal dysfunction is a clinical concept in the diagnostic and therapeutic management of sinonasal diseases, based on the evo-devo theory of formation of the nose according to which the nose is not a single organ but rather an association of three organs: olfactory nose, respiratory nose and paranasal sinuses. In chronic nasal dysfunction theory, etiological diagnosis takes account of the possible pathophysiological independence of nasal symptoms, in accordance with the different origins and physiology of the three organs constituting the nose. The diagnostic approach of the chronic nasal dysfunction concept breaks down the pathology so as to propose treatment(s) adapted to the diseased organ(s) and to the capacity for physiological resolution of dysfunction induced in one organ by pathology in a neighboring nasal organ. The ethmoid is not a sinus according to evo-devo, and therefore functional endoscopic endonasal surgery (FEES) cannot be restricted to functional endoscopic sinus surgery (FESS). Evo-devo theory and the chronic nasal dysfunction concept offer an alternative to the concept of chronic rhinosinusitis with or without polyps for the management of sinonasal diseases.

Resolution capacity of geophysical monitoring regarding permafrost degradation induced by hydrological processes

Abstract. Geophysical methods are often used to characterize and monitor the subsurface composition of permafrost. The resolution capacity of standard methods, i.e. electrical resistivity tomography and refraction seismic tomography, depends not only on static parameters such as measurement geometry, but also on the temporal variability in the contrast of the geophysical target variables (electrical resistivity and P-wave velocity). Our study analyses the resolution capacity of electrical resistivity tomography and refraction seismic tomography for typical processes in the context of permafrost degradation using synthetic and field data sets of mountain permafrost terrain. In addition, we tested the resolution capacity of a petrophysically based quantitative combination of both methods, the so-called 4-phase model, and through this analysed the expected changes in water and ice content upon permafrost thaw. The results from the synthetic data experiments suggest a higher sensitivity regarding an increase in water content compared to a decrease in ice content. A potentially larger uncertainty originates from the individual geophysical methods than from the combined evaluation with the 4-phase model. In the latter, a loss of ground ice can be detected quite reliably, whereas artefacts occur in the case of increased horizontal or vertical water flow. Analysis of field data from a well-investigated rock glacier in the Swiss Alps successfully visualized the seasonal ice loss in summer and the complex spatially variable ice, water and air content changes in an interannual comparison.

Application of Three Electrical Resistivity Arrays to Evaluate Resolution Capacity of Fractured Zones at Apatara Farms, Iwo, Osun State, Nigeria

The study applied three different electrical resistivity arrays (Wenner, dipole-dipole, and Pole-dipole) based on their resolution capacity to delineate fractured zones at Apatara Farm in Iwo, Osun State, Nigeria. Theoretical apparent resistivity data were computed for each model and contaminated with 5% Gaussian noise as a further concession to real field conditions. The simulated results revealed that the Wenner array gave the least error in trying to reconstruct the true model when the fractured zone is placed near the subsurface. However, when the fractured zone is placed at a depth beyond 5 m, the Dipole-Dipole array gave a better resolution than Pole-Dipole and Wenner array in decreasing order of resolution. The study further revealed that the Wenner array is less susceptible to edge effect at shallow depth while Dipole-dipole is more susceptible to edge effect at deeper depth followed by the Pole-dipole array. 2D electrical resistivity field measurements were carried out to confirm the results of the numerical simulation in the same field using the same parameters. The inverted resistivity images showed that the fractured zones are well delineated by the Dipole-dipole and Pole-dipole arrays but poorly resolved by the Wenner array. The study has demonstrated the usefulness of numerical modelling for imaging of fractured zone necessary for hydrogeological purpose and through modelling, the user has unlimited power to image or simulate a real-world scenario seamlessly before carrying out the actual field survey.Keywords: Electrical resistivity array; fractured zones; finite element method; 2-D models; resolution, mean absolute error

Distributed sensing technology of high-spatial resolution based on dense ultra-short FBG array with large multiplexing capacity

We developed a large multiplexing capacity dense ultra-short (DUS)-FBG array for high spatial resolution distributed sensing applications. With identical central wavelength and low peak reflectivity (−40 dB), all the ultra-short FBGs share the short length (1 mm) and extremely small spacing (500 μm). The large multiplexing capacity and lower crosstalk of the DUS-FBG is investigated through both simulation and experiment. Use of DUS-FBG array interrogated by optical frequency domain reflectometry (OFDR) for distributed temperature and non-uniform strain sensing was conducted. We demonstrated high spatial resolution over 6680 FBGs along a 10 m-long fiber, and temperature and strain precision of 1.00 °Cand 20.02 μe. Distributed temperature and non-uniform strain sensing experiment results are consistent with the theoretical analysis, and verify the high spatial resolution and large multiplexing capacity.

Estudio de mortalidad materna por sepsis en Antioquia, Colombia, entre los años 2004-2014: una mirada al desafío de la identificación y el tratamiento oportunos

Objetivo: describir las características de las mujeres e identificar los factores de la atención que contribuyeron a las muertes maternas por sepsis en el departamento de Antioquia, Colombia.Materiales y métodos: serie de casos de las muertes maternas causadas por infección entre los años 2004 y 2014. Se analizaron las muertes maternas con base en las recomendaciones de la “Campaña para sobrevivir a la sepsis”, y en guías de práctica clínica de infecciones específicas. Los juicios se realizaron por consenso. Se evaluaron la oportunidad del diagnóstico de sepsis, el tratamiento antibiótico, el choque séptico, la toma de cultivos, la terminación del embarazo, la realización de la cirugía para control del foco infeccioso, el ingreso a unidad de cuidados intensivos, la remisión a un nivel de complejidad mayor y la calidad global del manejo. Análisis descriptivo.Resultados: de 476 muertes maternas, 47 (9,87 %) mujeres fallecieron por sepsis de origen no obstétrico y 11 (5,2 %) por infecciones propias del embarazo o puerperio. La neumonía fue la principal causa de muerte. Los principales factores que influyeron en el desenlace fueron las demoras en identificar el síndrome, en iniciar los antibióticos, asumir el manejo en niveles con baja capacidad resolutiva, tratamiento inadecuado del choque séptico y la falta de modificación de las conductas terapéuticas ante el deterioro de las pacientes.Conclusión: las muertes maternas por sepsis estuvieron principalmente asociadas a causas no obstétricas; hay factores críticos tales como el retraso en la identificación del síndrome, y el inicio oportuno y adecuado de los antibióticos que son susceptibles de intervención.

Simulation of the influence of constant uniform magnetic field on a miniature LIT mass spectrometer.

In this paper, the effects of constant uniform magnetic fields on a miniature linear ion trap mass spectrometer with hyperbolic electrodes are simulated using SIMION 8.0 3D software. Magnetic fields in different directions have different effects on the trajectories of the trapped ions and the shape of the ion cloud. When the magnetic field is applied in the z-direction, namely the ion injection direction, the magnetic field will cause the ions focusing to the z-axis, and exert a compression effect on the ion cloud. When the magnetic field is applied in the x-y plane, the original ion cloud will be expanded due to the action of the applied magnetic field, and the ion cloud plane after expansion is always perpendicular to the direction of the magnetic field. The discovery of influence field of magnetic will bring some useful inspiration for the improvement of ion trapping efficiency, mass resolution, sensitivity and trapping capacity, which is conductive to the performance enhancement utilization of magnetic field, even in the industrial application development and other aspects.

Data-driven interdisciplinary mathematical modelling quantitatively unveils competition dynamics of co-circulating influenza strains

BackgroundCo-circulation of influenza strains is common to seasonal epidemics and pandemic emergence. Competition was considered involved in the vicissitudes of co-circulating influenza strains but never quantitatively studied at the human population level. The main purpose of the study was to explore the competition dynamics of co-circulating influenza strains in a quantitative way.MethodsWe constructed a heterogeneous dynamic transmission model and ran the model to fit the weekly A/H1N1 influenza virus isolation rate through an influenza season. The construction process started on the 2007–2008 single-clade influenza season and, with the contribution from the clade-based A/H1N1 epidemiological curves, advanced to the 2008–2009 two-clade influenza season. Pearson method was used to estimate the correlation coefficient between the simulated epidemic curve and the observed weekly A/H1N1 influenza virus isolation rate curve.ResultsThe model found the potentially best-fit simulation with correlation coefficient up to 96% and all the successful simulations converging to the best-fit. The annual effective reproductive number of each co-circulating influenza strain was estimated. We found that, during the 2008–2009 influenza season, the annual effective reproductive number of the succeeding A/H1N1 clade 2B-2, carrying H275Y mutation in the neuraminidase, was estimated around 1.65. As to the preceding A/H1N1 clade 2C-2, the annual effective reproductive number would originally be equivalent to 1.65 but finally took on around 0.75 after the emergence of clade 2B-2. The model reported that clade 2B-2 outcompeted for the 2008–2009 influenza season mainly because clade 2C-2 suffered from a reduction of transmission fitness of around 71% on encountering the former.ConclusionsWe conclude that interdisciplinary data-driven mathematical modelling could bring to light the transmission dynamics of the A/H1N1 H275Y strains during the 2007–2009 influenza seasons worldwide and may inspire us to tackle the continually emerging drug-resistant A/H1N1pdm09 strains. Furthermore, we provide a prospective approach through mathematical modelling to solving a seemingly unintelligible problem at the human population level and look forward to its application at molecular level through bridging the resolution capacities of related disciplines.

Diagonal rejection-based minimum variance distortionless response for fiber underwater acoustic array

The high mounting precision of the fiber underwater acoustic array leads to an array manifold without perturbation. Besides, the targets are either static or slowly moving in azimuth in underwater acoustic array signal processing. Therefore, the covariance matrix can be estimated accurately by prolonging the observation time. However, this processing is limited to poor bearing resolution due to small aperture, low SNR and strong interferences. In this paper, diagonal rejection (DR) technology for Minimum Variance Distortionless Response (MVDR) was developed to enhance the resolution performance. The core idea of DR is rejecting the main diagonal elements of the covariance matrix to improve the output signal to interference and noise ratio (SINR). The definition of SINR here implicitly assumes independence between the spatial filter and the received observations at which the SINR is measured. The power of noise converges on the diagonal line in the covariance matrix and then it is integrated into the output beams. With the diagonal noise rejected by a factor smaller than 1, the array weights of MVDR will concentrate on interference suppression, leading to a better resolution capability. The algorithm was theoretically proved with optimal rejecting coefficient derived under both infinite and finite snapshots scenarios. Numerical simulations were conducted with an example of a linear array with eight elements half-wavelength spaced. Both resolution and Direction-of-Arrival (DOA) performances of MVDR and DR-based MVDR (DR–MVDR) were compared under different SNR and snapshot numbers. A conclusion can be drawn that with the covariance matrix accurately estimated, DR–MVDR can provide a lower sidelobe output level and a better bearing resolution capacity than MVDR without harming the DOA performance.