Close Distance Research Articles

Experimental evaluation of wearable LED strip and side-emitting fiber for optical camera communications systems.

This paper presents an experimental evaluation of two types of light-emitting diode (LED)-based distributed transmitters, namely an LED strip and an LED-coupled side-emitting optical fiber, in both laboratory and wearable optical camera communication (OCC) systems. We study the system performance in terms of success of reception (SoR) with regard to the transmission distance. The best value of SoR is achieved when the camera is facing directly to the transmitter (Tx) from a close distance of 1 m. Additionally, we compare the power consumption, the signal-to-noise ratio performance (SNR) and all the obtained values under optimal conditions are better than the forward error correction (FEC) limit in OCC systems.

DECODING THE SEMANTIC VOLUME OF NOUNS WITH THE VERBAL MODALITY MÜSSEN: THE SYNERGISTIC DIMENSION OF LEAST EFFORT

The presented work is one of the stages of noun research within a certain verbal modality. The focus of the article lies in the study of the generating noun content in relation to the verbal modality müssen in German from the perspective of linguosynergetic scientific paradigm, which considers language as a complex dynamic system capable of self-organization and self-regulation. In this study methodologically important is the position that the synergetic law of making the least effort and conservation of speech energy is the driving factor of language development. In a synergetic sense, the author of the article draws parallels between the dictionary as a representative of the linguistic generalization of the structured amount of knowledge of the learned extraverbal reality and the mental lexicon, which is not an arbitrary accumulation of contributions, but constitutes a structured hierarchical system of such contributions. If lexical units in the synergetic sense and their meanings at the language level contain coded structured information, then in the same aspect the paper considers the implementation of the word in one of its meanings at the speech level as information decoding. The linguosynergetic format of the research proposed in this article assumes that language as a self-regulating system under the influence of external energy and information has developed a mechanism of different representations of nouns in syntactic constructions with different verbal modality in German-language fiction and press. The results obtained on the basis of the synergetic-quantitative approach are extrapolated to linguosynergetic models of self-organization of noun names according to the principle of minimization of efforts, which directs the human mental lexicon to optimal decoding of semantic volume of polysemic or monosemic nouns in relation to the verbal modality müssen in German-language fiction and press. It was proved that since the closest distances in the lexical structure of a word at the linguistic level are the closest in comparison with the structures of knowledge of the human mental lexicon, the construction of noun content in modern German on the synergetic principle of conservation of speech energy and minimization of efforts is the most optimal way of directing the mental lexicon of a person to decoding the semantic scope of the closets (main) meanings of the polysemic and unambiguous monosemic word models.

Effect of Computer Tasks in Straight Gaze on Corneal Topographic Indices.

To investigate the effect of the near visual task of movie-watching in the straight gaze position on corneal topographic parameters. Thirty myopic young adults with an average age of 25.10 4.13 years were recruited for the study. The designed near visual task consisted of watching a movie in the straight gaze position at a distance of 40 cm for 30 minutes. Corneal topography was performed using Oculus Keratograph 4 (OCULUS, Wetzlar, Germany) before and immediately after watching the movie, as well as at 10, 20, and 30 minutes intervals after completing this near visual task. Zernike coefficients, asphericity indices, refractive parameters, and diagnostic indices of keratoconus were recorded for statistical analysis. Movie-watching at a close distance solely using the straight gaze position had no effect on Zernike coefficients (P 0.130). Also, watching the movie had no effect on other corneal topography parameters including irregularities (P = 0.208), spherical eccentricity (P = 0.270), maximum decentration (P = 0.553), axis of maximum decentration (P = 0.186), peripheral astigmatism (P = 0.179), and average asphericity of the quadrants at 10 to 30º (P 0.163). The results of the present study showed that watching movies in the straight gaze position had no effect on corneal topographic parameters and did not cause errors in corneal topographic measurements.

Experimental study of sound wave propagation patterns

The present study compares the behavior of different sound types and their sources concerning distance. Experimental findings demonstrate a consistent reduction in noise levels with increasing distance from the sound origin, aligning with anticipated sound propagation patterns. Median noise level reductions are quantified, showing decreases from 72.7 dB at the source to 54.8 dB at a distance of 3 m. Pulsed sounds exhibit pronounced fluctuations and peaks at close distances, while steady and blended sounds maintain more uniform levels. An exponential model accurately characterizes the noise reduction phenomenon (R² = 0.8664), underscoring its applicability for construction noise control. These results offer valuable insights into sound propagation dynamics and provide a basis for developing effective noise control strategies.

Monocular Vision Guidance for Unmanned Surface Vehicle Recovery

The positioning error of the GPS method at close distances is relatively large, rendering it incapable of accurately guiding unmanned surface vehicles (USVs) back to the mother ship. Therefore, this study proposes a near-distance recovery method for USVs based on monocular vision. By deploying a monocular camera on the USV to identify artificial markers on the mother ship and subsequently leveraging the geometric relationships among these markers, precise distance and angle information can be extracted. This enables effective guidance for the USVs to return to the mother ship. The experimental results validate the effectiveness of this approach, with positioning distance errors of less than 40 mm within a 10 m range and positioning angle errors of less than 5 degrees within a range of ±60 degrees.

Genomic analysis of PIN-FORMED genes reveals the roles of SmPIN3 in root architecture development in Salvia miltiorrhiza

Salvia miltiorrhiza is a widely utilized medicinal herb in China. Its roots serve as crucial raw materials for multiple drugs. The root morphology is essential for the quality of this herb, but little is known about the molecular mechanism underlying the root development in S. miltiorrhiza. Previous study reveals that the polar auxin transport is critical for lateral root development in S. miltiorrhiza. Whether the auxin efflux carriers PIN-FORMEDs (PINs) are involved in this process is worthy investigation. In this study, we identified nine SmPIN genes in S. miltiorrhiza, and their chromosome localization, physico-chemical properties, and phylogenetic relationship were analyzed. SmPINs were unevenly distributed across four chromosomes, and a variety of hormone responsive elements were detected in their promoter regions. The SmPIN proteins were divided into three branches according to the phylogenetic relationship. SmPINs with close evolutionary distance showed similar conserved motif features. The nine SmPINs showed distinct tissue-specific expression patterns and most of them were auxin-inducible genes. We generated SmPIN3 overexpression S. miltiorrhiza seedlings to investigate the function of SmPIN3 in the root development in this species. The results demonstrated that SmPIN3 regulated the root morphogenesis of S. miltiorrhiza by simultaneously affecting the lateral root development and the root anatomical structure. The root morphology, patterns of root xylem and phloem as well as the expressions of genes in the auxin signaling pathway all altered in the SmPIN3 overexpression lines. Our findings provide new insights for elucidating the regulatory roles of SmPINs in the auxin-mediated root development in S. miltiorrhiza.

Sentiment Analysis of Google Play Store User Reviews on Digital Population Identity App Using K-Nearest Neighbors

The Digital Population Identity Application provides convenience for users to access and manage their population data digitally. Based on the increasing usage of the Digital Population Identity Application on the Google Play Store, various user reviews of the application have emerged. Therefore, sentiment analysis is needed to provide a deeper understanding of user perceptions and to classify user reviews of the Digital Population Identity Application. Sentiment analysis is a computational study of opinions, feelings, and emotions expressed in text, using the K-Nearest Neighbors method, which is a classification method based on the closest distance or similarity to objects in the training data. Using 5000 relevant review data from September 2022 to December 2023, after labeling them into positive, negative, and neutral sentiment classes, the results show 3581 negative sentiments, 1031 positive sentiments, and 388 neutral sentiments. Testing was conducted by applying the K-Nearest Neighbors method in the classification stage, testing this method by varying K values from 1 to 10. The best results were obtained with a training data ratio of 90% to testing data ratio of 10%. The best results were achieved at K values of 8, 9, and 10, with an accuracy of 81%, precision of 82%, recall of 95%, and an F1-Score of 88%. With a training data ratio of 70% to testing data ratio of 30%, the best results were obtained at K values of 6, 7, 8, 9, and 10, with an accuracy of 80%, precision of 81%, recall of 95%, and an F1-Score of 88%. Based on the results of this research, the K-Nearest Neighbors method can be used for sentiment classification of user reviews with good results.

Kinase Inhibition via Small Molecule-Induced Intramolecular Protein Cross-Linking.

Remarkable progress has been made in the development of cysteine-targeted covalent inhibitors. In kinase drug discovery, covalent inhibitors capable of targeting other nucleophilic residues (i.e. lysine, or K) have emerged in recent years. Besides a highly conserved catalytic lysine, almost all human protein kinases possess an equally conserved glutamate/aspartate (e.g. E/D) that forms a K-E/D salt bridge within the enzyme's active site. Electrophilic ynamides were previously used as effective peptide coupling reagents and to develop E/D-targeting covalent protein inhibitors/probes. In the present study, we report the first ynamide-based small-molecule inhibitors capable of inducing intramolecular cross-linking of various protein kinases, leading to subsequent irreversible inhibition of kinase activity. Our strategy took advantage of the close distance between the highly conserved catalytic K and E/D residues in a targeted kinase, thus providing a conceptually general approach to achieve irreversible kinase inhibition with high specificity and desirable cellular potency. Finally, this ynamide-facilitated, ligand-induced mechanism leading to intramolecular kinase cross-linking and inhibition was unequivocally established by using recombinant ABL kinase as a representative.

Kinase Inhibition via Small Molecule‐Induced Intramolecular Protein Cross‐Linking

AbstractRemarkable progress has been made in the development of cysteine‐targeted covalent inhibitors. In kinase drug discovery, covalent inhibitors capable of targeting other nucleophilic residues (i.e. lysine, or K) have emerged in recent years. Besides a highly conserved catalytic lysine, almost all human protein kinases possess an equally conserved glutamate/aspartate (e.g. E/D) that forms a K–E/D salt bridge within the enzyme's active site. Electrophilic ynamides were previously used as effective peptide coupling reagents and to develop E/D‐targeting covalent protein inhibitors/probes. In the present study, we report the first ynamide‐based small‐molecule inhibitors capable of inducing intramolecular cross‐linking of various protein kinases, leading to subsequent irreversible inhibition of kinase activity. Our strategy took advantage of the close distance between the highly conserved catalytic K and E/D residues in a targeted kinase, thus providing a conceptually general approach to achieve irreversible kinase inhibition with high specificity and desirable cellular potency. Finally, this ynamide‐facilitated, ligand‐induced mechanism leading to intramolecular kinase cross‐linking and inhibition was unequivocally established by using recombinant ABL kinase as a representative.

Digital-SMLM for precisely localizing emitters within the diffraction limit

Abstract Precisely pinpointing the positions of emitters within the diffraction limit is crucial for quantitative analysis or molecular mechanism investigation in biomedical research but has remained challenging unless exploiting single molecule localization microscopy (SMLM). Via integrating experimental spot dataset with deep learning, we develop a new approach, Digital-SMLM, to accurately predict emitter numbers and positions for sub-diffraction-limit spots with an accuracy of up to 98 % and a root mean square error as low as 14 nm. Digital-SMLM can accurately resolve two emitters at a close distance, e.g. 30 nm. Digital-SMLM outperforms Deep-STORM in predicting emitter numbers and positions for sub-diffraction-limited spots and recovering the ground truth distribution of molecules of interest. We have validated the generalization capability of Digital-SMLM using independent experimental data. Furthermore, Digital-SMLM complements SMLM by providing more accurate event number and precise emitter positions, enabling SMLM to closely approximate the natural state of high-density cellular structures.

IoT based Smart Surveillance with Landmine Detection and Alerts

The research uses a Node MCU microcontroller and Internet of Things (IoT) technology to create a robot for handheld applications. The robot has a night vision camera that connects to the internet, allowing it to take photos and videos from a distance, even at night. It also has a metal detector to find landmines and an infrared (IR) sensor to detect obstacles and prevent accidents. These sensors immediately notify and alert users through LCD screens, messages, and buzzers. The research aims to develop a robot with increased accessibility and user friendliness by offering simple manual and operator controls for robotic inspection. The high-definition camera provides clear photos and videos for detailed analysis of any suspects, helping to make informed decisions quickly and improve situational awareness. On detecting a landmine, the robot alerts the user through the email and displays the information on the LCD screen, enhancing the safety at checkpoints. The IR sensor helps the robot avoid obstacles by alerting the user and sounding a buzzer when something is detected at a close distance. This feature allows the robot to navigate complex environments safely. Overall the robot is designed to provide a smart surveillance by offering an immediate threat response to handle the security concerns in various situations.

How to make recommendations on mobile social e-commerce more effective: The role of social features and temporal cues

This study explores the role of design affordance of social display features in mobile social e-commerce with recommendations. Building upon the intersection of signaling theory and construal level theory, we address two paradoxes regarding social and temporal cues in recommending (close social distance vs. limited feedback and recency vs. magnitude). The results from four experiments indicate that friend-based feedback induces larger purchases than crowd-based feedback. Temporal distance moderates this relationship. Specifically, when temporal cues indicate proximal distance, recommendations from friends (by showing their feedback) are more persuasive than those from crowds. Conversely, the opposite occurs at further temporal distance.

Effect of early versus late onset of partial visual loss on judgments of auditory distance.

It is important to know whether early-onset vision loss and late-onset vision loss are associated with differences in the estimation of distances of sound sources within the environment. People with vision loss rely heavily on auditory cues for path planning, safe navigation, avoiding collisions, and activities of daily living. Loss of vision can lead to substantial changes in auditory abilities. It is unclear whether differences in sound distance estimation exist in people with early-onset partial vision loss, late-onset partial vision loss, and normal vision. We investigated distance estimates for a range of sound sources and auditory environments in groups of participants with early- or late-onset partial visual loss and sighted controls. Fifty-two participants heard static sounds with virtual distances ranging from 1.2 to 13.8 m within a simulated room. The room simulated either anechoic (no echoes) or reverberant environments. Stimuli were speech, music, or noise. Single sounds were presented, and participants reported the estimated distance of the sound source. Each participant took part in 480 trials. Analysis of variance showed significant main effects of visual status (p<0.05) environment (reverberant vs. anechoic, p<0.05) and also of the stimulus (p<0.05). Significant differences (p<0.05) were shown in the estimation of distances of sound sources between early-onset visually impaired participants and sighted controls for closer distances for all conditions except the anechoic speech condition and at middle distances for all conditions except the reverberant speech and music conditions. Late-onset visually impaired participants and sighted controls showed similar performance (p>0.05). The findings suggest that early-onset partial vision loss results in significant changes in judged auditory distance in different environments, especially for close and middle distances. Late-onset partial visual loss has less of an impact on the ability to estimate the distance of sound sources. The findings are consistent with a theoretical framework, the perceptual restructuring hypothesis, which was recently proposed to account for the effects of vision loss on audition.

A research on destress mechanism of underlying roadway for gas outburst prevention in deep, low‐permeability coal seam

AbstractGas outbursts pose a significant threat in the mining of deep low‐permeability coal seams. As mining depth increases, there is a rise in coal and gas dynamic disasters, rendering the gas outburst prevention technology from shallow mining areas unsuitable for deep coal seam exploitation. Addressing the challenges posed by deep, highly gassy coal seams, this study introduces a gas outburst prevention technology integrating destressing in the close distance underlying roadway with gas drainage. The article investigates the relevant technical parameters and assesses the feasibility of this approach. First, it establishes destressing model for the underlying roadway to derive an analytical solution for stress distribution in the coal seam. Second, appropriate technical parameters are designed considering the seepage characteristics of gas in the coal seam. Finally, the gas drainage technical scheme is implemented at Qujiang coal mine to verify its on‐site effectiveness. Field test results indicate an increase in gas permeability within the coal seam following destressing in the underlying roadway, accompanied by significant improvements in the efficiency of gas drainage and the advancement speed of the coal roadway. Specifically, the driving speed of the coal roadway has escalated from 40 m/month to 150 m/month. These outcomes demonstrate the potential of this technology as a promising approach for preventing gas outbursts in the challenging context of deep, low‐permeability coal seams, facilitating swift coal roadway excavation.

Greater distance from the glenosphere center to the acromion reduces risk of acromial impingement in semi-inlay reverse shoulder arthroplasty

BackgroundRecently, the issue of subacromial notching, caused by acromial impingement has been reported. The purpose of this study was to assess the impact of differences in the distance between the glenosphere center and the greater tuberosity (DGT) and the distance between the glenosphere center and the acromion (DA) on the closest distance between the greater tuberosity and the acromion during active abduction in shoulders with reverse total shoulder arthroplasty (RSA). MethodsEleven shoulders with semi-inlay RSA were analyzed. Subjects underwent fluoroscopy during active scapular plane abduction. Computed tomography of their shoulders was performed to create 3-dimensional implant models at a mean of 16 months after surgery. Using model-image registration techniques, poses of 3-dimensional implant models were iteratively adjusted to match their silhouettes with the silhouettes in the fluoroscopic images (shape matching), and 3-dimensional kinematics of implants were computed. The closest distance between the acromion and greater tuberosity was computed at maximum abduction. DA and DGT were measured from 3-dimensional surface models. Shoulders were divided into two groups based on DA and DGT measurements and their closest distance data were compared between the groups. ResultsThere were 7 shoulders with DA ≥ DGT, and 4 shoulders with DA < DGT. Shoulders with DA ≥ DGT showed a significantly wider distance between the greater tuberosity and acromion at maximum abduction compared to those with DA < DGT (5.9 ± 2.4 mm vs. 0.6 ± 0.7 mm, respectively, P = 0.0021). There were no significant differences in maximum glenohumeral abduction angle and humeral abduction angle between the two groups. Although DA was significantly greater in shoulders with DA ≥ DGT than in those with DA < DGT (43.7 ± 4.4 mm vs. 35.1 ± 6.7 mm, respectively, P = 0.0275), there was no significant difference in DGT between the two groups. ConclusionsWhen DGT is less than DA in shoulders with RSA, the closest distance between the greater tuberosity and the acromion at maximum abduction is significantly wider compared to cases where DGT is greater than DA by 3-dimensional measurement. Therefore, acromial impingement is less likely to occur in shoulders with RSA when DA is greater than DGT. To avoid acromial impingement, it might be important to make DA greater than DGT.

Stability control of goaf‐driven roadway surrounding rock under interchange remaining coal pillar in close distance coal seams

AbstractThe roadway surrounding rock stability under the influence of interchange remaining coal pillar in close distance coal seams is one of the key factors affecting the coal mines safe and efficient mining. To reduce the roadway deformation, theoretical analysis, numerical simulation, and on‐site verification were used to study the influence of geological, mining, and support factors on the stability of the floor roadway surrounding rock. A design method for strengthening the roadway surrounding rock support was proposed. The results showed that the coal seam depth, the distribution characteristics of the remaining coal pillar load, the starting point position of stress recovery in the upper coal seam goaf and the lower coal seam goaf lateral load had a significant influence on the lower coal seam stress. The peak stress in the lower coal seam increased linearly with the increase of the coal seam depth, the remaining coal pillar, and the lower coal seam goaf lateral peak stress. The remaining coal pillar influence area width increased linearly and exponentially with the increase of the remaining coal pillar width and the distance between the starting point of stress recovery in goaf and the coal pillar edge, respectively. The peak stress and shear strength of the narrow coal pillar decreased exponentially with the increase of the spacing between bolts or cables. The roadway surrounding rock deformation decreased exponentially with the increase of the distance between the strengthening support area and the remaining coal pillar edge. For the Baigou coalmine, a design scheme for bolt strengthening support parameters has been proposed. The roadway surrounding rock deformation tended to stabilize after 21 days, with deformation values of 264 and 488 mm for the roof and floor, and two sides, respectively.

Operational Radiation Safety Considerations During Equine Superficial Radiation Treatment Using Portable X-Ray Devices

Abstract Veterinary personnel exposure due to scattered x rays, when present during superficial radiation treatment (SRT), was evaluated. Veterinary personnel presence is needed during SRT to minimize the degree of required aesthesia to horses. Animal treatment was simulated, and exposure rates determined for 50, 70, and 100 kV x rays using eight different SRT applicators. Exposure rates at the surface of a solid water phantom (SWP) phantom ranged from 3.9 mR h−1 to 396 mR h−1 for 50 kV, from 41 mR h−1 to 2,880 mR h−1 for 70 kV, and from 235 mR h−1 to 7,500 mR h−1, for 100 kV, respectively. A horse phantom was used to mimic SRT equine ocular treatment creating a spatial exposure field where the directional scatter was measured at 1 m. The minimum distance away from the source to reach &lt; 2 mR h−1 varied with angular position and energy and was lowest for all energies directly behind the x-ray tube. The closest distance before exceeding 2 mR h−1 at 50 kVp was determined to 1.96 m. A worker could stand 1 m behind the x-ray tube at 50 kVp with 0.25 mm lead for 15,106 hours. Typical SRT treatment times for horse eyelid squamous cell carcinoma are less than 5 minutes, and radiation doses to practitioners are expected to be well below local administrative ALARA limits.

Influence of tissue-electrode distance on unipolar and bipolar voltage for large-tip, ring-, and mini-electrodes

Abstract Background The characteristics of intracardiac unipolar and bipolar voltage electrograms (EGM) acquired by electrophysiological catheters depend on the electrical source and on the electrode design and configuration. Purpose The aim of the study was to assess the impact of the electrode configuration and their distance from the myocardial tissue (electric source) on the unipolar and bipolar intracardiac electrograms recorded with a multi-electrode focal ablation catheter. Methods We retrospectively analyzed left atrial 3D electroanantomical maps (EAMs) of 25 patients performed in sinus rhythm using the IntellaNav Mifi OI catheter (Boston Scientific, USA) with a 4.5 mm tip-electrode, three mini-electrodes and three 2 mm ring electrodes. The unipolar and bipolar EGMs were characterized based on the peak-to-peak amplitude (amp), the signal duration (width), the maximal slope, and the relative high power spectrum (HF_rel) as ratio of the power spectrum of frequencies above and below 50Hz. Distances of the electrode from the tissue were calculated from the electroanatomic reconstruction. Except for the HF_rel with absolute values are reported, all characteristics are normalized using the tip-electrode for unipolar or tip-to-ring electrode values for bipolar measures. EGMs with bipolar voltage amplitude of &amp;gt;0.5 mV were included to focus on healthy tissue. Results We analyzed the EGMs of 5183 catheter positions with horizontal to perpendicular orientation. From horizontal catheter orientation with a similar distance from the tissue for all electrodes, the unipolar EGM of the ring electrodes showed an increased amplitude (140%), slope (150%) and HF_rel (16% vs 11%) compared to the tip- and mini-electrodes. For bipolar EGM, however, the tip- ring pair showed the largest amplitude, width, and slope. The HF_rel was larger for the ring electrode pairs compared to the tip-ring electrode (58% to 39%). The median amplitude (amp), slope, and HF_rel for the ring electrodes showed a strong power-law decay function with distance, whereas the width increases linearly with distance from the surface (Figure, blue dotted lines). The intersection (red circle) of the steep linear decline at close distance to the tissue (reflecting a strong influence on the EGM) with the flat line at larger distances (dash-dotted lines) was considered as nearfield boundary. A HF_rel cutoff of &amp;gt;10% for unipolar (Figure, red arrow) and &amp;gt;30% for bipolar EGMs might be used to identify this boundary. Conclusion We confirmed a higher amplitude for small ring-electrodes compared to larger tip electrodes in unipolar amplitude but not for bipolar electrograms. Furthermore, a strong decay of the amplitude, slope and HF_rel with distance could be observed. The decay functions are suggestive for a nearfield boundary distance below 4mm from the tissue. Further studies are warranted to confirm this observation.Summary of characteristics over distance

Effects of phase angle and sensor properties on on-orbit debris detection using commercial star trackers

The recent proliferation of resident space objects (RSOs) in low Earth orbit (LEO) threatens the sustainability of space as a resource and requires persistent monitoring to avoid collisions involving valuable space assets. State-of-the-art ground-based space surveillance techniques, due to their susceptibility to atmosphere, weather, and lighting conditions, tend to focus on RSOs with characteristic length greater than 10 cm or 1 dm. Consequently, millions of smaller LEO RSOs remain untracked by ground-based methods, which reduces overall space situational awareness. Onboard satellite sensors offer a space-based method for tracking RSOs. Prior research has investigated the feasibility of using commercial star trackers (CSTs) — optical sensors prevalent on most active spacecraft — to observe, detect, and estimate the position and velocity of RSOs larger than 10 cm. In a recent effort, we expanded on these feasibility studies by assessing the capabilities of CSTs to detect debris particles smaller than 10 cm in characteristic length. We modeled the particles as Lambertian spheres with zero phase angle and ten percent reflectivity and found that typical CSTs can detect properly illuminated debris of characteristic length between 1 cm and 10 cm even at distances of tens of kilometers. More sensitive CSTs can characterize decimeter-scale RSOs hundreds of kilometers away; alternatively, they can track centimeter-scale and smaller RSOs at closer distances. In this paper, we summarize these key results and extend our previous study by relaxing its zero-phase-angle assumption and characterizing the effect of Sun-RSO-CST phase angle on debris detection range. We identify a number of representative CSTs with publicly available optical characteristics and consider the effects of properties such as pixel pitch, focal length, aperture diameter, and field of view (FOV) on the capability of each CST to detect debris at a given distance and relative velocity (in the form of streak speed). We find that, for debris particles modeled as diffuse Lambertian spheres, Sun-RSO-CST phase angles as high as 57° result in no more than 20% reduction to the useful RSO-CST detection range. In addition, we find that pixel pitch and focal length, rather than aperture diameter, tend to determine the capability of a given CST to resolve two distinct RSOs. Furthermore, streak speed may serve as a stronger limiting factor for detection of smaller debris particles than for larger ones. Despite these limitations, the overall results indicate that CSTs have the potential to substantially enhance space-based debris detection capability.

Correction: Study on Roof Deformation and Failure Law of Close Distance Coal Seams Mining Based on Digital Image Correlation

Correction: Study on Roof Deformation and Failure Law of Close Distance Coal Seams Mining Based on Digital Image Correlation