Limited Visibility Research Articles

APPLICATION OF WIRELESS COMMUNICATION AND TECHNICAL VISION TECHNOLOGIES TO IMPROVE AVIATION SEARCH AND RESCUE OPERATIONS

The subject of research in the article is approaches to improving the onboard equipment of a search and rescue aircraft (AC). The purpose of the study is to develop proposals for improving the technical means of searching for aircraft that have suffered an accident, namely video surveillance systems and information transmission to the control centers (CC) of the search and rescue operation, based on the analysis of the Rules for Search and Rescue Support of Flights of the State Aviation of Ukraine and foreign experience in search and rescue operations. It is proposed to use a light multipurpose helicopter of the Mi-2 type as a search and rescue aircraft (SRAC). The work solves the following problems: studying modern approaches to ensuring aviation search and rescue operations; analyzing technical means of ensuring the search for crashed aircraft; developing proposals for a method of transmitting information from the airborne control center to the ground control center; selecting a suitable carrier for special equipment and individual samples of video surveillance and data transmission systems. The method of comparative analysis is used to solve partial problems. The following results have been obtained: the requirements for the search characteristics of SRAC are determined, in particular, it is proposed to use a light multipurpose helicopter as SRAC; a scheme for organizing communication with the search operation control center using wireless communication technologies is presented; specific requirements for individual components of SRAC onboard special equipment are formulated. Conclusions. The introduction of wireless communication technologies together with thermal imaging equipment will increase the speed and efficiency of searching for crashed aircraft, especially at night and in conditions of limited visibility (fog, smoke). In addition, the range of tasks of light helicopters such as the Mi-2 is expanding, and the number of both onboard and ground operators directly using thermal imaging equipment (infrared camera) to determine the location of the crash is increasing. In this case, the total number of personnel involved in search and rescue operations is not affected.

Pelatihan Menggambar Dengan Teknik Menggambar Perspektif Pada SMK Negeri 9 Medan

Perspective or point of view is a technique or method for drawing objects in the form of objects, rooms (interiors), and environments (exteriors) that are larger in size than humans. This technique was created due to the limited visibility of our eyes in seeing objects. The farther the eye can see, the smaller it appears and will even disappear from view at a certain distance. Conversely, the closer our eyes look, the object will appear bigger. Two things must be used as a benchmark in perspective drawing techniques. Perspective in general means images that are used to communicate objects in the form of objects, spaces, environments that are visible to the human eye on a flat plane. Perspective drawing is an image that technically uses a vanishing point. Perspective drawing itself is a form of 3-dimensional images.

Virtual Mirrors: Non-Line-of-Sight Imaging Beyond the Third Bounce

Non-line-of-sight (NLOS) imaging methods are capable of reconstructing complex scenes that are not visible to an observer using indirect illumination. However, they assume only third-bounce illumination, so they are currently limited to single-corner configurations, and present limited visibility when imaging surfaces at certain orientations. To reason about and tackle these limitations, we make the key observation that planar diffuse surfaces behave specularly at wavelengths used in the computational wave-based NLOS imaging domain. We call such surfaces virtual mirrors. We leverage this observation to expand the capabilities of NLOS imaging using illumination beyond the third bounce, addressing two problems: imaging single-corner objects at limited visibility angles, and imaging objects hidden behind two corners. To image objects at limited visibility angles, we first analyze the reflections of the known illuminated point on surfaces of the scene as an estimator of the position and orientation of objects with limited visibility. We then image those limited visibility objects by computationally building secondary apertures at other surfaces that observe the target object from a direct visibility perspective. Beyond single-corner NLOS imaging, we exploit the specular behavior of virtual mirrors to image objects hidden behind a second corner by imaging the space behind such virtual mirrors, where the mirror image of objects hidden around two corners is formed. No specular surfaces were involved in the making of this paper.

Effect of water salinity on properties of multipass underwater wet manual metal arc welded joints

The weldability of steel under the water is limited due to the influence of the environment. Water causes limited visibility, presence of the residual stresses, increasing the cooling rate, and increasing the diffusible hydrogen content in deposited metal, leading to the formation of brittle microstructures in heat-affected zone (HAZ). The paper presents the results of mechanical properties testing of S420G2+M steel welded joints made with covered electrodes in the water with salinity values: 0‰, 7.5‰, and 35‰. The non-destructive tests: ultrasonic (UT) and radiographic (RT), and destructive tests: Vickers HV10 measurements, Charpy impact, and bending and metallographic macro- and microscopic tests were performed. Moreover, the diffusible hydrogen content in deposited metal by the mercury method was measured. It was observed that water salinity has an influence on the stability of the welding arc and the properties of joints. In particular, it was found that increasing the water salinity provides to: decreasing the hardness of HAZ (from 211 HV10 to 193 HV10), increasing the impact strength (from 82.5 to 101.3 J/cm2). Additionally, a slight increase in the diffusible hydrogen content in deposited metal (up to 65 ml/100g) was observed. The number of microcracks in the joints decreased with increasing the water salinity.

RESEARCH OF THE CIRCUMSTANCES OF COLLISIONS AT REGULATED INTERSECTIONS WITH LIMITED VISIBILITY OF ESCORTED COLUMNS OF VEHICLES WITH OTHER VEHICLES

The article analyzes the requirements of the current Traffic Rules of Ukraine regarding the conditions for the movement of motorcades and aspects of the occurrence of traffic accidents at controlled intersections with limited visibility with the participation of a column of cars accompanied by another vehicle. The options for expert studies to establish the causes of traffic accidents in non-standard situations were studied and recommendations were proposed for including additions to the Traffic Rules of Ukraine regarding the installation of special light and sound signals and devices on the cars accompanied by the convoy, as well as to unify the terminological concepts of «immediate proximity» and «safe distance» when the column is moving. The authors consider it appropriate: – to consider the possibility of introducing additions by the relevant authorities to Article 25 of the Traffic Rules of Ukraine regarding the installation of special light and sound signals and devices on the cars of the accompanied column of vehicles, as an additional factor in attracting the attention of other road users and avoiding dangerous moments at regulated intersections when passing the accompanied columns cars; – during the briefing, provide for the obligations of the drivers of the convoy of cars in case of division of cars into groups while driving, to comply with the requirements of the Traffic Rules of Ukraine, based on the current conditions for the passage of cars at regulated intersections; – to coordinate in the articles of the Rules the terminological concepts «immediate proximity» and «safe distance», which are used in the current requirements of the Traffic Rules of Ukraine.

Visual environment of rearing sites affects larval response to perceived risk in poison frogs.

Turbidity challenges the visual performance of aquatic animals. Here, we use the natural diversity of ephemeral rearing sites occupied by tadpoles of two poison frog species to explore the relationship between environments with limited visibility and individual response to perceived risk. To compare how species with diverse natural histories respond to risk after developing in a range of photic environments, we sampled wild tadpoles of (1) Dendrobates tinctorius, a rearing-site generalist with facultatively cannibalistic tadpoles and (2) Oophaga pumilio, a small-pool specialist dependent on maternal food-provisioning. Using experimental arenas, we measured tadpole activity and space use first on a black and white background, and then on either black or white backgrounds where tadpoles were exposed to potentially predatory visual stimuli. The effects of rearing environment on D. tinctorius tadpoles were clear: tadpoles from darker pools were less active than tadpoles from brighter pools and did not respond to the visual stimuli, whereas tadpoles from brighter pools swam more when paired with conspecifics versus predatory insect larvae, suggesting that tadpoles can visually discriminate between predators. For O. pumilio, tadpoles were more active on experimental backgrounds that more closely matched the luminosity of their rearing sites, but their responses to the two visual stimuli did not differ. Larval specialisation associated with species-specific microhabitats may underlie the observed responses to visual stimuli. Our findings demonstrate that light availability in wild larval rearing conditions influences risk perception in novel contexts, and provides insight into how visually guided animals may respond to sudden environmental disturbances.

An Effective Multi-Agent Ant Colony Optimization Algorithm for QoS-Aware Cloud Service Composition

In order to improve the efficiency of wireless network virtualization resource processing, this paper combines the dynamic resource allocation algorithm to construct a wireless network virtualization resource sharing model. This paper proposes a task-oriented resource management model and uses the task-oriented TRS model to describe resources and service processes, reducing the complexity of formulating resource allocation strategies. Moreover, this paper comprehensively considers factors such as centralized coordination control cost and limited domain topology visibility to improve the dynamic resource allocation algorithm. Through the abstraction and unified representation of network resources, resource sharing, and efficient reuse, the coexistence and integration of heterogeneous wireless networks can be realized. Wireless network virtualization can decouple complex and diverse network management and control functions from hardware and extract them to the upper layer for unified coordination and management, thereby reducing network management costs and improving network management and control efficiency

Walking performance of pedestrians in corridors under different visibility conditions

Visibility is an important factor affecting pedestrian movement and safe evacuation. To investigate the walking characteristics of pedestrians under limited visibilities, a novel measurement method by changing the light transmittance in a suitable lighting environment is proposed to achieve different visibility levels. A series of individual movement experiments were performed under the quantitative control of visibility condition. Stoop-walking behavior was observed at low visibility levels. Besides, pedestrians would stretch out their arms or feet to explore the surrounding environment under invisible conditions. Based on the high-precise trajectories, it is found that the acceleration and relaxation time of individuals increase with the improvement of visual condition. The walking speed of males is significantly larger than that of females at the same visibility level. Moreover, individual speed increases with the improvement of visibility level, but no significant difference is found when the visual distance is larger than 6 m. In addition, individuals prefer to change movement direction rather than reduce the speed to avoid the frontal obstacle or pedestrians under limited visibilities. Furthermore, comparison between previous studies and our work is made, and their differences are also elaborated. The study can help to quantitatively predict pedestrian’s speed and develop movement models for limited visibility situations.

Arthroscopic Posterior HAGL Repair Using a Direct Transaxillary Portal

Humeral avulsion of the glenohumeral ligament (HAGL lesion) is a challenging problem in surgery for shoulder instability. Open and arthroscopic approaches and techniques have been described to address this issue. Especially posterior HAGL lesions increase the surgical complexity, as open anterior approaches provide limited visibility and access for successful repair. This article describes an alternative technique using an arthroscopic transaxillary approach to deploy the suture anchor with a perpendicular angle to the humeral bone, thus, improving the ability to perfectly position the anchor at the anatomic insertion of the inferior humeral ligament.

A Fast Sand Dust Image Enhancement Algorithm and Number Plate Detection

Abstract: The color variation and limited visibility of images taken in sand-dust conditions have a significant negative impact on computer vision systems. We suggest a quick and efficient approach to improve photographs taken in sand-dust weather in order to address the aforementioned issues. First, we make amends for the blue channel's loss value. The color of the image that has been damaged by sand dust is then corrected using white balance technology. In order to improve the image contrast and edge accuracy, guided image filtering is utilized, and an adaptive approach is used to determine the detail layer's magnification factor in order to improve the image detail information. We also added an additional feature of number plate detection of the sandy images.The aim of this task is to develop an automated system that can accurately and efficiently detect and recognize number plates from sandy images captured by a camera. This technology has various applications, such as traffic control, toll collection, parking management, and law enforcement. The experimental results demonstrate that the approach can successfully restore the fading characteristics of a large number of sand-dust-damaged photos. The proposed method may considerably improve the photos acquired during sand-dust weather conditions, and the results are better than those of existing methods, according to experimental results via qualitative and quantitative assessments

Wind Gust Parameters in the Lower Troposphere Based on Doppler Lidar Data

AbstractWind gusts are common small‐scale weather phenomena characterized by a rapid increase in wind speed over a short period of time. Wind gusts affect a wide range of interests, including aviation safety, wind energy and professional skiing, while strong gusts can also cause severe weather events and limit visibility. However, the characteristics of gusts in the lower troposphere are not yet well understood, especially at the top of the boundary layer. In this paper, the gust parameters in the lower atmosphere at different heights and their diurnal variation characteristics are examined based on Doppler lidar data from the gentle coastal topography of Shandong Province, China. The results show that all the gust parameters have distinct stratification characteristics, with significantly different diurnal variations below 400 m, between 400 and 1,200 m, and above 1,200 m (above the ground, same below). Wind gusts are considered to be the result of turbulent disturbances superimposed on the background airflow, and strong turbulence could cause the instantaneous winds to significantly deviate from the mean airflow. The magnitude of the peak gust is mainly controlled by the mean flow, but the gust factor, which is the ratio of the peak gust to the mean flow, is almost independent of the mean flow and has a strong positive correlation with the turbulence intensity. These results imply that gusts of different properties occur at varying altitudes, with differences depending on turbulence intensity and mean airflow, and provide an observational basis for studies of gust structure.

Enhancing the order-to-delivery process with real-time performance measurement based on digital visualization

ABSTRACT This study examined the order-to-delivery (OTD) process that employ real-time performance measurement based on digital visualization (DV). It was performed as a longitudinal case study using the design science approach. The case company delivers customized technology solutions to its customers, with a specific focus on the OTD process of maintenance services. DV, it was found, is a powerful tool capable of enhancing the performance measurement of the OTD process. Determining the focal points that DV-based real-time performance measurement focuses on facilitates the implementation of the performance implications of the process. Further, these performance implications are the result of an appropriate interplay between real-time performance measurement and DV. The study addresses the voice of workers to avoid possible bias concerning the views of management or the limited visibility of certain areas of the company. This study is among the first to examine performance measurement that uses novel technologies to enhance decision-making.

Design and Fabrication of Automated Shopping Cart System

In cities, shopping malls experience high rush on holidays and weekends, particularly with offers and discounts. To minimize time spent at billing counters, a project proposes equipping merchandise in malls with RFID tags and trolleys with RFID readers and digital displays. This smart shopping trolley solution aims to enhance the shopping experience by addressing long queues, difficulty-finding products, and limited pricing visibility. The project focused on a small, cost-efficient, and user-friendly design, gathering ideas from group members. The trolley has been, successfully designed and fabricated, tested under loading conditions, meeting requirements. It is easy to use, requiring no special training, and benefits both retailers and customers by serving more customers simultaneously.

A Data-Based Tool Failure Prevention Approach in Progressive Die Stamping

The research on methods for monitoring sheet metal stamping is benefiting from the increased availability of enabling technologies such as sensors, data mining software, cloud computing, and artificial intelligence. The predictive maintenance policies of tools (punches and dies) can be targeted at monitoring progressive wear or at the detection of sudden failures or anomalies. Early detection of tool failure is the method preferred by the recent literature on data management in sheet metal stamping. However, the stamping of small parts poses challenges due to multiple tools and signals and limited visibility of die wear, requiring management of multiple sensors and data sources. This paper proposes a failure prevention approach for progressive die stamping using global and local force sensors with upper bounds for maximum values to indicate unhealthy conditions. The methodology was tested on millions of small washers made of carbon steel. The stamping process was implemented using a servo-press with a high rate. The press was equipped with eight in-process sensors, including strain gauges, thin foil force sensors, and acoustic sensors. The data of material properties, maintenance reports, statistical process control data, and in-process sensors were collected and stored in a data lake. By combining the in-process sensor acquisition with the corresponding log events and maintenance data in the same time span, it is possible to look for correlations among the variables and build an effective tool health prevention policy.

HydraMarker: Efficient, Flexible, and Multifold Marker Field Generation.

An n-order marker field is a special binary matrix whose n×n subregions are all distinct from each other in four orientations. It is commonly used to guide the composing process of position-sensing markers, which can be detected and identified in a camera image with very limited scope or severe visibility problems. Despite the advantages, position-sensing markers are rare and overlooked because generating marker fields is difficult. In this article, we broaden the definition of marker field, making it more powerful and flexible. Then, we propose bWFC (binary wave function collapse) and its high-speed version, fast-bWFC, to solve the generation problem. The methods are packaged into an open-sourced toolkit named HydraMarker, with which, users not only can generate marker fields on laptops within a short period of time, but also can highly customize them: preset values; fields and subregions in any shape; multifold local uniqueness. Comparative results indicate that the proposed method has superior efficiency, quality, and capability. It makes marker field generation accessible to common marker designers, opening up more possibilities for fiducial markers.

The Future of Mine Safety: A Comprehensive Review of Anti-Collision Systems Based on Computer Vision in Underground Mines.

Underground mining operations present critical safety hazards due to limited visibility and blind areas, which can lead to collisions between mobile machines and vehicles or persons, causing accidents and fatalities. This paper aims to survey the existing literature on anti-collision systems based on computer vision for pedestrian detection in underground mines, categorize them based on the types of sensors used, and evaluate their effectiveness in deep underground environments. A systematic review of the literature was conducted following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to identify relevant research work on anti-collision systems for underground mining. The selected studies were analyzed and categorized based on the types of sensors used and their advantages and limitations in deep underground environments. This study provides an overview of the anti-collision systems used in underground mining, including cameras and lidar sensors, and their effectiveness in detecting pedestrians in deep underground environments. Anti-collision systems based on computer vision are effective in reducing accidents and fatalities in underground mining operations. However, their performance is influenced by factors, such as lighting conditions, sensor placement, and sensor range. The findings of this study have significant implications for the mining industry and could help improve safety in underground mining operations. This review and analysis of existing anti-collision systems can guide mining companies in selecting the most suitable system for their specific needs, ultimately reducing the risk of accidents and fatalities.

Tension between the safe flow of government data across organizational boundaries and fragmentations in secure collaboration: the Chinese e-government

PurposeThe study focuses on influential factors of collaboration on government data security by the Chinese government.Design/methodology/approachThe article explores the case of e-government in the Chinese centralized unitary state system context, using a structured–pragmatic–situational (SPS) approach and the boundary theory as an analytical lens.FindingsThe findings indicate that e-government operates in highly interconnected environments where the safe flow of government data requires collaborative and cross-boundary strategies. Any organization is a potential “weakest link”. In addition, collaboration is fragmented by ambiguous accountability and organizational inertia across government departments, resources differences and limited visibility and measurability of security efforts across government levels and conflicts and uncertainties in principal–agent relationships. The solutions for those obstacles are also discussed from the multi-function, multi-level and multi-actor dimensions, respectively. A multi-dimensional overarching security model for the flow of government data is proposed.Originality/valueThe study advances the technology-oriented micro-analysis of previous studies on government data security to cross-organizational revealing at the macrolevel by connecting streams of research in information systems and public administration. These findings will contribute to making the safe flow of government data more resilient in the transformation of e-government.

Opportunities for Early Detection and Prediction of Ransomware Attacks against Industrial Control Systems

Industrial control systems (ICS) and supervisory control and data acquisition (SCADA) systems, which control critical infrastructure such as power plants and water treatment facilities, have unique characteristics that make them vulnerable to ransomware attacks. These systems are often outdated and run on proprietary software, making them difficult to protect with traditional cybersecurity measures. The limited visibility into these systems and the lack of effective threat intelligence pose significant challenges to the early detection and prediction of ransomware attacks. Ransomware attacks on ICS and SCADA systems have become a growing concern in recent years. These attacks can cause significant disruptions to critical infrastructure and result in significant financial losses. Despite the increasing threat, the prediction of ransomware attacks on ICS remains a significant challenge for the cybersecurity community. This is due to the unique characteristics of these systems, including the use of proprietary software and limited visibility into their operations. In this review paper, we will examine the challenges associated with predicting ransomware attacks on industrial systems and the existing approaches for mitigating these risks. We will also discuss the need for a multi-disciplinary approach that involves a close collaboration between the cybersecurity and ICS communities. We aim to provide a comprehensive overview of the current state of ransomware prediction on industrial systems and to identify opportunities for future research and development in this area.

How to Design the eHMI of AVs for Urgent Warning to Other Drivers with Limited Visibility?

The importance of an external interaction interface (eHMI) has grown in recent years. Most eHMI concepts focus on communicating autonomous vehicle (AV)'s yielding intention to pedestrians at a crossing. However, according to previous studies, pedestrians at a crossing rely mainly on the vehicle's movement information (implicit communication) rather than information from eHMIs (explicit communication). This paper has the purpose of proposing a specific use case in which the eHMI of future AVs could play an indispensable role in the safety of other road users (ORUs). Often VRUs cannot see the traffic flow due to a series of parked or stopped vehicles, which is a frequent cause of fatal traffic collision accidents. Drivers may also not be able to see approaching pedestrians or other cars from the side for the same reason. In this paper, the impact of an eHMI is tested from the perspective of drivers with limited visibility when a jaywalker steps into the road. A combination of colors, shapes, and information levels is presented on an eHMI. We show that our proposed eHMI design, in the deadlock scenario of a jaywalker and a driver who both lack visibility, significantly reduced the reaction time compared to when there was no eHMI. In the experiment, the willingness to stop, varying from 0 to 5, was measured from the driver's perspective. The results showed that most users felt uncertainty and did not move quickly when seeing the light band color alone. Textual information on the eHMI was significantly more effective in providing an urgent warning of this specific scenario than vertical and horizontal light bands with color without text. In addition, red color, blinking rapidly above 3 Hz, and egocentric messages were also necessary to reduce the PRT(perception response time). By using text-added eHMI (Vertical + Text eHMI), the mean time to achieve a score above 4 for willingness to stop was 2.113 s faster than when there was no eHMI. It was 2.571 s faster than the time until the slider of the participants reached the maximum level for willingness to stop. This is a meaningful amount of difference when considering a PRT of 2.5 s, which is the Korean road design standard. As eHMIs tend to be applied for smarter mobility, it is expected that they will be more effective in preventing accidents if the eHMI is standardized in autonomous driving level 2 to 3 vehicles driven by humans before fully autonomous driving becomes a reality.

Training arthrocentesis and arthroscopy: Using surgical navigation to bend the learning curve

ObjectiveTemporomandibular joint arthroscopy and arthrocentesis are generally considered safe and minimally invasive surgical procedures. For an inexperienced surgeon, the complex anatomy of the surgical field and the limited visibility represent a significant challenge, and many surgical training programmes are considered limited in providing the adequate training.Technological advancements, involving surgical navigation, facilitate planning, execution, and evaluation of various complex surgical treatments and represent a very promising addition to the surgical training toolkit. TechniqueThis article presents the use of surgical navigation as an additional training tool in teaching level I and II arthroscopy to resident surgeons. Surgical navigation is used to aid the trainee by controlling the starting point and angulation, inspect anatomical landmarks and discus consequences of errors in angulation. While the trainee performs the puncture, the instructor oversees both the surgical field and the anatomy on the surgical navigation screen. ConclusionIt is demonstrated that real-time guidance provided by a surgical navigation system can be used as a training tool for surgeons with limited previous experience in arthroscopic procedures. This application could help improve the safety for the patient and provide a deeper educational level in training surgeons. Still, clinical and tactile feedback perioperatively should remain a primary guideline. Factors such as financial investments, challenges in implementation and a steep learning curve regarding the navigation system must be considered.