Industrial enterprises have high requirements on timeliness and cost when delivering industrial products to their customers. For this reason, this paper studies the vehicle routing problem (VRP) of different vehicle models in multiple distribution centers. First of all, we consider the multi-dimensional constraints in the actual distribution process such as vehicle load and time window, and build a multi-objective optimization model for product distribution with the goal of minimizing the distribution time and cost and maximizing the loading rate of vehicles. Furthermore, an Improved Life-cycle Swarm Optimization (ILSO) algorithm is proposed based on the life cycle theory. Finally, we use the order data that Yunnan Power Grid Company needs to deliver to the customer  on a certain day to conduct a dispatching experiment. The simulation and application results show that the transportation cost of transportation obtained by the ILSO algorithm is reduced by 0.8% to 1.6% compared with the other five algorithms. Therefore, ILSO algorithm has advantages in helping enterprises reduce costs and improve efficiency. Therefore, many enterprises urgently need to reduce transportation costs. At present, the loading rate of trucks used by the Metrology Center of China Southern Power Grid Co., Ltd to distribute electric power metering devices (a kind of electric power equipment) to the municipal power supply bureau is only about 55%, which wastes a lot of transportation resources2. In view of the current problems in the electric power equipment logistics distribution system of power enterprises, such as low quality and efficiency of decision-making, unscientific and unreasonable scheduling2, this paper studies the corresponding VRP problem against the background of the electric power equipment logistics distribution of Yunnan Power Grid Corporation, so as to successfully help power enterprises achieve cost reduction and efficiency increase. The logistics distribution of electric power equipment can be summed up as the problem of highway trunk transportation in cargo transportation. The core of trunk transportation is to solve the problem of trunk transportation no-load rate3, that is, to increase the quantity of electric power equipment delivered by a single vehicle on the premise of ensuring the delivery time. Below, we briefly describe the specific characterization of the problem, in which the business model flowchart is shown in Fig. The Council of Supply Chain Management Professionals (CSCMP) in its "33rd annual state of logistics report" shows that although the inventory of American commercial logistics enterprises fell to the lowest level in history in 2021, the related transportation costs increased by 21.7%5.For power grid enterprises, there are usually multiple distribution centers that deliver goods to the municipal power supply bureau within their jurisdiction, and the models of transportation vehicles in the distribution centers are different. For example, China Southern Power Grid Co., Ltd has four logistics distribution centers in different cities. Its customers  are also distributed in different cities, and each logistics distribution center has different transport vehicles to distribute electric power equipment. In order to maintain profitability, the transportation companies only carry out the distribution task when the actual load tonnage of vehicles is higher than the minimum load limit. In addition, it is also necessary to consider the time window limit of the arrival time of electric power equipment required by each municipal power supply bureau. Therefore, the distribution of electric power equipment has the characteristics of multiple vehicle types, covering multiple cities, and multiple distribution centers. It is a multi-objective complex vehicle routing problem (VRP) involving many constraintsIn view of the above problems, different from the existing research, this paper constructs a multi-objective optimization model involving power equipment distribution. In the case of considering more real constraints, the minimum fitness function of distribution cost, the minimum fitness function of delivery time and the maximum fitness function of the municipal power supply bureau for single vehicle distribution are built, which makes the established mathematical model more practical. Further, we developed a heuristic algorithm, which draws on the biological life cycle characteristics to improve the group search optimization algorithm (GSO). Then, the variant group strategy is introduced to design an improved life-cycle swarm optimization (ILSO) algorithm for the model solution. Finally, based on the actual business scenario data, the simulation experiments are compared with other heuristic algorithms.The paper is organized as follows: in Section “Literature review”, we present the existing literature studies. In Section “Modeling the distribution path problem of heterogeneous vehicles for industrial products in multiple-depot with time windows”, we construct the corresponding mathematical model. In Section “Model solution based on ILSO algorithm”, we design the ILSO algorithm. In Section “Results and analysis”, we show the simulation results with the application of the model and algorithm. Finally, in Section “Conclusion”, we summarize the whole paper.6. Further, Clarke et al. proposed a heuristic algorithm called C-W saving algorithm to solve VRP problem7. On this basis, relevant researchers have carried out extensive research on the problem, improved relevant models and algorithms, and studied the variants of VRP9. Therefore, this paper reviews the problem from three aspects: relevant models, algorithms and variants of the problem.The VRP problem was first proposed by Dantzig et al. in 1959 in order to solve the distribution problem of oil tank trucks10. For the logistics distribution of multiple distribution centers in most researches, each distribution center is responsible for the customers in one region11. Unfortunately, this method is not applicable to the distribution problem due to the different inventory structure of each distribution center for industrial products, the influence of the logistics distribution radius of industrial products, and the transfer costs imposed by the legal permit system. In addition, some researchers have simplified the vehicle routing problem of multiple distribution centers to the vehicle path problem of a single distribution center12. Sadati et al. studied the trilevel r-interdiction selective multi-center vehicle routing problem (3LRI-SMDVRP)13. When Xiang Yang et al. studied the logistics distribution problem of multiple distribution centers, they established the corresponding objective function, but only minimized the distribution cost without involving other dimensions such as distribution time14. La Vega et al. studied the logistics distribution problem of a fleet of vehicles with the same type without considering the different models of contracted carriers15. Z. Su et al. studied the heterogeneous vehicle logistics distribution problem based on the parallel heuristic algorithm, but it does not involve the logistics distribution of multiple distribution centers16.At this stage, most of the research on logistics distribution focus on a single distribution center17. However, similar to literature12, it only establishes the single objective function of the lowest distribution cost, and does not consider the two objectives of vehicle utilization and distribution duration, nor does it consider the constraints of different types of vehicles. Srivastava et al. studied the multi-objective, single-center, single-type vehicle routing problem, and focused on the two objectives of distribution cost and distribution time18. Similarly, this work did not consider the vehicle utilization. On this basis, literature19 studies the path planning problem of vehicles with multiple objectives, single centers and multiple models. From the above work, it can be concluded that the current work on VRP has not established the corresponding mathematical model with the goal of minimum distribution cost, minimum distribution time and maximum utilization of distribution vehicles. There is no work to study the VRP problem of multi-target, multi-center and different types of vehicles at the same time. In addition, the above research is mostly based on some assumptions, such as the assumption that as long as there are goods vehicles, they will be delivered. This is not true in reality. The distribution company will deliver only after the loading rate of vehicles reaches a certain threshold.The multi-center VRP problem was studied in literature5. Exact algorithms struggle to give effective solutions when the objective function and constraints are complex. Heuristic algorithms20 are widely used because of their better parallelism and low requirements on the characteristics of the objective function21. Montes et al. and Onieva et al. studied the optimization of logistics distribution paths based on evolutionary strategies23. Further, Peng Jiang et al. developed an evolutionary multi-objective algorithm24 to reduce the risk of dangerous goods transportation, based on which Z. Zhang et al. developed a multi-objective local search (MOLS) algorithm to avoid the algorithm from falling into local optima during the operation25. To solve the large-scale vehicle routing problem quickly and improve the algorithm's convergence accuracy, Y. Zhou et al. introduced a weight-space partitioning strategy and proposed a decomposition-based local search algorithm26. In addition, algorithms such as Ant Colony Optimization29, Genetic Algorithm31, and Particle Swarm Optimization34 are also widely used in the field of logistics and distribution routing optimization. In the process of algorithm improvement, all aforementioned algorithms aim to improve the convergence speed and shorten the search time.Most of the studies in the literature on algorithms for solving VPR problems are exact and heuristic algorithms36. Laithadualigah et al. successfully applied GSO algorithm to function selection (FS) problem in machine learning field, and studied the application of improved GSO search strategy in multi-objective optimization problem37. Further, Hamidteimourzadeh et al. established a single objective mathematical model with the goal of reducing the total loss of the distribution system. In order to make the GSO algorithm have better performance in solving such problems, they improved the GSO algorithm according to the problem characteristics38. Literature39 also introduced the mechanism of intraspecific competition (IC) and the searching strategy of Lévy walk (LW) into the basic GSO algorithm to improve the performance of the GSO algorithm. It can be seen that GSO algorithm and its improved algorithm have been widely used in optimization problems, but it is worth pointing out that because of the characteristics of the search strategy composed of discoverer, follower and wanderer in GSO algorithm, only the discoverer can change the search direction, and its ability to jump out of the local extreme value is not strong in the limited solution space. In addition, no relevant researchers have applied GSO algorithm to VRP problems and variants of VRP problems. According to the characteristics of GSO algorithm and based on the characteristics of biological life cycle, an improved life-cycle swarm optimization (ILSO) algorithm is designed to solve the model.The basic Group Search Optimizer (GSO) algorithm has been widely used in optimization problems since it was proposed in 200640; Based on the background of emergency rescue after the disaster, the humanitarian logistics problems41. In addition, VRP is also applied to other fields. For example, Fanjul-Peyro et al. studied the machine scheduling problem in the manufacturing industry, improved the traditional VRP problem, and established a linear programming model for the machine scheduling problem42. Literature43 also improves the traditional VRP problem and applies it to the berth allocation and crane allocation of the terminal.With the further exploration of VRP by researchers, many variants of VRP have been developed at this stage. For example, the traditional VRP problem is improved, and the green VRP problem is generated with the goal of reducing carbon emissionsEach order of a commercial customer company must correspond to a time-effective shipping permit issued by the administrative department, and the order must be delivered within the validity period of the shipping permit.Orders cannot be shipped by the way of cross-warehouse  per vehicle trip is provided.Assume that each distribution center has enough industrial products of each model. However, due to the different warehouse models and inventory structures of various distribution centers, their outgoing capabilities are also different. Assume that the stacking gap is not considered in the consideration of the maximum load capacity, the default is no gap, different specifications of cargo packaging are the same. The unloading time is the same at each commercial customer company: three hours. Industry enterprises stipulate that when the no-load rate of each vehicle is less than 5%, a subsidy of 40 China Yuan  when the vehicle is empty is neglected, leading to incomplete optimization and other problems. Therefore, this paper further improves the mathematical model established in document41, and builds the objective functions for shortest transportation time, lowest transportation cost, and most customers served by a single vehicle. Taking multiple objectives into account ensures the lowest transportation cost and shortest distribution time, improves the vehicle loading rate as much as possible, avoids wasting resources, and optimizes transportation routes and vehicle allocation. These improvements all contribute to improved distribution of industrial products.Molina et al. established an adaptation degree function with minimum transportation cost and maximum service customers based on the heterogeneous vehicle path problem with hard time windows, which is valuable for the heterogeneous vehicle scheduling problemCalculation rules for logistics, distribution, and transportation costs of industrial products are as follows:Therefore, this paper aims to minimize the transportation time, minimize the transportation cost, and maximize the average number of customers distributed by each vehicle. The model of the distribution route problem of heterogeneous vehicles with time windows for products in multiple distribution centers is as follows:-th commercial customer company, which is easy to know from the assumption The total time formulas , 6) and and\docuformulas .5\documeThe constraints of this article are shown in formulas -18)..18).s.t.mentclasspt{minimamentclasspt{minima34. However, when solving a problem with strong constraints, the optimal solution produced may no longer meet the requirements, and many local optimal solutions may also be produced. In addition, traditional mathematical optimization methods or some exact methods start from a single point in the search space and determine the next point through specific conversion rules. Compared with swarm intelligence optimization algorithms, their parallelism is lower. Therefore, this paper adopts the Life-cycle Swarm Optimization (LSO) algorithm, which is based on the life cycle characteristics of organisms and varies the number of populations in the algorithm. Further, we innovatively use the logistic population prediction model to predict the number of individuals in the control population and dynamically adjust the number of individuals in the population. This method simulates the natural evolution process of the population in the biological world. By making the population individuals more diverse, convergence happens faster in the optimization process. One can also control the time cost of the algorithm and improve the solution speed. The LSO algorithm provides an excellent choice to solve the problem of cargo distribution. Moreover, the LSO algorithm represents the parameter set of the problem as an individual and runs in the form of code instead of solving the parameters themselves as in traditional optimization algorithms. Therefore, when a computer processes the complex logistics scheduling model, the algorithm in this paper has good operability.The basic Group Search Optimizer (GSO) algorithm has been widely used in optimization problems since it was proposed in 2006Parameter initialization.Initialize the population randomly.Assess the fitness value.Perform chaotic chemotaxis operation: use Logistic equation to perform a chaotic search on the basis of the best individual in the current population.Perform assimilation or transposition operation: the assimilation operation makes the individual evolve toward the optimal individual position, and the transposition operation makes the individual search within the energy range of its own.Perform a breeding operation: pair the individuals in the population in sequence and perform a single-point crossover operation.Perform death operations: sort the population individuals linearly according to their fitness values, adjust the fitness values, and select individuals for better optimization using roulette.Perform mutation operation: change the evolution direction of the population according to the mutation probability.Update the global extremum: calculate the fitness of individuals in the current population and update the current optimal individuals.Iterative update of population individuals:If the preset iteration stop condition is reached, the optimal solution and its fitness value will be output; if not, return to step 4.The basic LSO algorithm simulates the main processes of the life cycle, including growth, development, reproduction, and death. The summary of the basic LSO algorithm is as follows:k-th generation, the transportation scheduling plan represented by the i-th individual;u-th distribution center;When applying the algorithm to a specific model, it is necessary to design the specific structure of the solution according to the actual problem, so that the problem can be adapted to the algorithm. The ILSO is divided into different phases to optimize different aspects of the problem at hand, just like how individuals go through different stages in their life cycle. And it draws on the characteristics of the biological life cycle: the number of individuals in the biological population is constantly changing, which conforms to the logistic population growth model. The ILSO algorithm also incorporates reproduction and mutation, which are biological processes that help population adapt and evolve over time. We also adopt multi-point crossover instead of single-point crossover to breed offspring individuals, and add roulette strategy when eliminating individuals. Based on this, we proposed the ILSO algorithm.The algorithm flow chart is shown in Fig. In the LSO algorithm, the position of an individual represents a solution to the problem, that is, a transportation scheduling plan. Due to the complex and complementary constraints of the model in this paper, the coding scheme must be intelligently designed, or it will be difficult to optimize the problem. But after modeling the problem reasonably and expressing the solution structure of the problem with an appropriate coding scheme, the algorithm proposed in this paper is suitable for most logistics scheduling optimization problems and has good adaptability.th vehicle of the model. The order group Based on this model, for a transportation scheduling scheme Due to the constraints of the upper and lower limits of vehicle loading and the number of orders, the allocation of orders is restricted. When the number of orders increases, the schemes that meet all constraints will drastically decrease, which is not conducive to the optimization of the algorithm. First, divide a batch of orders into several order groups, and filter the order groups that meet the upper and lower limits of vehicle loading and the number of orders. This initial optimization of the population individuals avoids the situation where the fitness of a large number of individuals in the population is extremely low.Initialize the Find the number of vehicles Repeat steps 1 and 2 to generate Based on the above discussion, the population initialization steps are as follows:The schematic diagram of the initial population generation is shown in Fig. After The fitness value of the individual is calculated by the objective function. The corresponding law of the objective function is denoted as Map  formula .19\docum(n + 1)-th chaotic variable 2. From the initial chaotic variable 3. The chaotic variable sequence -th generation optimal transportation scheduling plan, that is, let 4. Calculate The chaotic chemotaxis operation is a global search operation, which prevents the algorithm from falling into a local optimum due to insufficient search capabilities. The logistic equation is a typical chaotic system. The specific steps of using the logistic equation to perform chaotic operations on the optimal transportation scheduling plan Except for the best individual in the population, other individuals perform assimilation or transposition operations according to the selection probability The mathematical model of k-th generation.The multipoint crossover was used for two individuals to reproduce offspring individuals according to the crossover probability The original algorithm uses a linear sorting method to adjust the population individuals according to their fitness values, and the adjusted fitness values are arranged in descending order, and then the individuals are selected by the roulette method. On this basis, this paper uses the logistic population growth model to control the number of individuals in each generation. The number of population individuals dynamically changes according to the logistic population growth model, which can shorten the algorithm's running time while ensuring the accuracy of convergence.-th generation of the population is Assuming that the number of individuals in the kIn this paper, we use the elite strategy, i.e., the best individual is retained each time the roulette is performed, to prevent the best individual of the population from being eliminated, resulting in the algorithm's stability being affected.Calculate the probability of each individual being inherited into the k + 1 generation population from the fitness value Calculate the cumulative probability of each individual Randomly generate random numbers The roulette algorithm uses the idea that each individual's probability is proportional to its fitness. The implementation steps are as follows:Mutation is used to promote the diversification of individuals in the population and prevent the algorithm from falling into a local optimum. The individual Then  kg. The location codes for each commercial customer company are shown in Table In this section, we take an example of some pending orders for delivery on a particular day from China Southern Power Grid Co., Ltd,. The order information is shown in Table The parameters of the algorithm, such as the population size, are shown in Table The algorithm programming tool in this paper was MATLAB R2017a, the operating system was Windows 10, the computer memory was 16G, and the CPU was Intel i7-8750H. For comparison, the developed algorithm was compared with five other biological heuristic algorithms including Bat Algorithm (BA), Particle Swarm Algorithm (PSO), Whale Algorithm (WOA), Gray Wolf Algorithm (GWO), Mayfly Algorithm (MA), and conducted fifteen simulation experiments in total. The results are as follows, including the planning results of the ILSO algorithm during the fifteen runs of each algorithm randomly selected Table . The comIn Table A further experiment involved selecting the city name from the database and randomly generating a series of orders of different numbers corresponding to the valid time of the transportation permit. We conducted 16 random generation orders, and the order quantity increased from 15 to 30. This examined the stability and dynamic performance of the algorithm, and the effect of varying the number of orders on the running time of each algorithm and the optimal objective function. The results over sixteen runs are shown in Fig. Figure In addition, in order to further study the stability and reliability of the algorithm, we also conducted the Solomon's benchmark test of vehicle routing problem with time window constraints and parameter sensitivity analysis of ILSO algorithm. The average iteration curve after 50 runs of each of the six algorithms is shown in Fig. In Table In the following, we show the developed model and the interface of the algorithm applied to the scheduling system of China Southern Power Grid Co., Ltd. In addition, a screenshot of the order details interfaces after the logistics distribution multi-objective optimization model and ILSO algorithm has been calculated for a certain day's order is exhibited. It includes the order quantity, the number of vehicles of the delivered customer company, and the required vehicle information, as shown in Fig. CNY, which will enable the group to save at least CNY per year on freight costs. In addition, Table The above simulation experimental results show that the ILSO algorithm proposed in this paper is very applicable to the strongly constrained problem of logistics distribution by multi-center heterogeneous vehicles under multidimensional constraints. Table Furthermore, from the convergence curves of each algorithm's optimal, worst, and average objective function in the fifteen runs of the five algorithms Figs. , 8, 9 anThis research focuses on the logistics and distribution of industrial products. It focuses on the cross-regional heterogeneous vehicle scheduling mathematical model and algorithm design of multi-distribution centers and multi-municipal power supply bureaus. It develops an ILSO, making it the best in solving forty commercial client companies 6380 dan industrial products.First, a mathematical model of cross-regional heterogeneous vehicle scheduling with multiple distribution centers and multiple municipal power supply bureaus was established, and the ILSO algorithm was further developed. Then, finally, by processing the pending orders of China Southern Power Grid Co., Ltd, one day. The overall results show that the ILSO algorithm has higher convergence speed, convergence accuracy, and lower computing time than the other five biological heuristic algorithms. Furthermore, compared with the other five algorithms, the results of this algorithm reduce transportation costs by 0.8%-1.6% and reduce computing time by 47.78%-60.42%. Moreover, the ILSO algorithm can solve large-scale examples in the shortest time. It can be effectively applied in the dispatching system developed by the group, effectively solving the multi-objective complex heterogeneous vehicle routing problem involving numerous constraints.


Achieving the target for eliminating tuberculosis (TB) in India by 2025, 5 years ahead of the global target, critically depends on strengthening the capacity of human resources as one of the key components of the health system. Due to the rapid updates of standards and protocols, the human resources for TB health care suffer from a lack of understanding of recent updates and acquiring necessary knowledge.Despite an increasing focus on the digital revolution in health care, there is no such platform available to deliver the key updates in national TB control programs with easy access. Thus, the aim of this study was to explore the development and evolution of a mobile health tool for capacity building of the Indian health system’s workforce to better manage patients with TB.This study involved two phases. The first phase was based on a qualitative investigation, including personal interviews to understand the basic requirements of staff working in the management of patients with TB, followed by participatory consultative meetings with stakeholders to validate and develop the content for the mobile health app. Qualitative information was collected from the Purbi Singhbhum and Ranchi districts of Jharkhand and Gandhinagar, and from the Surat districts of Gujarat State. In the second phase, a participatory design process was undertaken as part of the content creation and validation exercises.The first phase collected information from 126 health care staff, with a mean age of 38.4 (SD 8.9) years and average work experience of 8.9 years. The assessment revealed that more than two-thirds of participants needed further training and lacked knowledge of the most current updates to TB program guidelines. The consultative process determined the need for a digital solution in easily accessible formats and ready reckoner content to deliver practical solutions to address operational issues for implementation of the program. Ultimately, the digital platform named Ni-kshay SETU (Support to End Tuberculosis) was developed to support the knowledge enhancement of health care workers.The development of staff capacity is vital to the success or failure of any program or intervention. Having up-to-date information provides confidence to health care staff when interacting with patients in the community and aids in making quick judgments when handling case scenarios. Ni-kshay SETU represents a novel digital capacity-building platform for enhancing human resource skills in achieving the goal of TB elimination. Mycobacterium tuberculosis, is a significant public health concern in developing countries such as India. Despite being a preventable and curable disease, TB kills 1.4 million people a year worldwide, making it the leading global infectious disease killer and a major contributor to antimicrobial resistance [Tuberculosis (TB), caused by sistance . To combsistance , under iHealth care workers under the NTEP are critical in reducing the burden of TB-related problems. Despite being engaged and trained in the program, the ever-changing program guidelines, introduction of new strategies and innovations, and continuous changes in the mode of care services delivery within the health system pose challenges in keeping the entire workforce up to date with all necessary information . Health Although continuous refresher training helps those working in the field strengthen their knowledge, develop a positive attitude, and prevent the spread of TB in the community, the COVID-19 pandemic added a significant challenge to physical capacity building and direct support/training ,6. AlthoDigital technology holds a promising future in dealing with capacity-building issues among health care workers . In partThus, the aim of this study was to showcase the evolution of the design of a digital platform for the capacity building of Indian health systems in TB care. Further, this study provides a skeleton of digital health innovations and their process, describing the design and delivery of a new digital platform as a ready reckoner and decision-making tool for the health workforce to better manage TB.The study was performed using a two-phase approach from March 2021 to January 2022. First, a qualitative research methodology was used to understand the key gaps and the need to enhance knowledge among health care workers working directly or indirectly with the NTEP. The synthesis of data collected from this first phase initiated the second phase to address the need to strengthen the capacity-building component through development of a digital health solution for sustainable implementation of the NTEP.The qualitative research phase of the study was performed in the Purbi Singhbhum and Ranchi districts of Jharkhand state and in the Gandhinagar and Surat districts of Gujarat state. Under the NTEP, a district is divided into TB Units (TUs), each covering an approximate population of 0.5 million. A total of 13 TUs were identified as an area for this qualitative investigation. Each TU has a Designated Microscopy Center (DMC), each covering a population of approximately 0.1 to 0.12 million. Under the NTEP’s integration policy, each DMC is located on the government’s general health facility premises. A DMC represents the crucial entry point or “gateway” for a patient with suspected or confirmed TB to access the TB diagnostic and treatment services offered by the NTEP. Any patient with suspected or confirmed TB must officially visit the DMC to enroll in the TB program. In addition, other government-run and private health facilities are operating in the areas surrounding the DMCs.Various stakeholders from the state (Gujarat and Jharkhand) and central health divisions were consulted on the design process of the digital platform.A purposive sampling strategy was applied to ensure diversity of cadres and maximum variation in responses for interviews, resulting in recruitment of 126 health care staff directly or indirectly involved in TB patient care. The line lists of the staff from the study settings were obtained from the state TB cell offices. Cadre-wise and work-wise distributions were applied to the line lists at the levels of health facility, TU (block), district, and state. The study participants were from the public sector  or consultants from various organizations and private settings . Additionally, field-level health staff such as community health officers, multipurpose workers, and accredited social health activists (ASHAs) were included in the study .The second phase involved a consultative group for a participatory discussion or one-to-one meetings with NTEP stakeholders to understand their views on the requirements for capacity building of health staff. The consultative meetings were not structured with a defined methodology and the stakeholder consultations aimed toward developing solutions that address the knowledge gaps and needs of the health care workers. There were 46 consultative meetings conducted nationwide with multiple stages to seek the reflections of stakeholders on the qualitative study findings from phase one and to consult them on the development of the digital solution. The participants were from the government , technical experts from private organizations and medical colleges, along with clinical specialists from the pulmonology field.In-depth one-to-one interviews were conducted in the regional language using an interview guide developed by the principal investigator and coinvestigators trained in NTEP guidelines. Consent was obtained and interviews were electronically recorded. The interview guides were pilot-tested and questions were restructured as needed. Social cognitive theory was used as a guiding framework for this study as it helps to understand human actions, intuitions, motivations, and processes of behavior change that determine training needs. There were 126 study participants with their assigned days’ availability to provide open-ended qualitative interviews. The interviews were continued until saturation of the responses from the participants was reached. After each interview, topics-based memos were written that enabled capturing different perspectives to address and create solutions based on the training need requirements of health staff for strong implementation of the NTEP. In some cases, participants were revisited to gather more insight.Audio-recorded data from interviews of health care providers were transcribed verbatim and translated into English. During the interview, verbatim notes were taken. On the same day of the interviews, transcripts were created using the verbatim notes of a coinvestigator in the field. The principal investigator read the collected transcripts to become familiar with the data once compiled. The transcripts were analyzed manually using descriptive content analysis. A second researcher skilled in qualitative research techniques reviewed the data to check for credibility and eliminate bias. The coding conventions and the theme creation were determined by consensus and according to accepted practices . Any difThe second phase included group or individual participatory discussions with stakeholders about outcomes related to the themes and findings from the first phase of the study. This consultative phase was designed to address the needs of health care workers in the management of patients with TB in line with national NTEP guidelines. The end goal of the discussions was to determine potential solutions to solve knowledge gaps experienced by health care workers. There were three areas of focus to these discussions: (1) delay in services to patients with TB, (2) gaps in knowledge of health care providers that lead to delays in services, and (3) possible digital solutions to enhance the knowledge of health care providers . An iterApproval for carrying out this study was obtained from the Institutional Review Board of the Indian Institute of Public Health, Gandhinagar, Gujarat (TRC-IEC 18/2020-21). Permission for carrying out the study was obtained from the State TB Office, Government of Gujarat and Jharkhand State. Written consent was obtained from all study participants.The qualitative enquiry and consultation exercise culminated in development of a digital platform named Ni-kshay SETU (Support to End Tuberculosis). This digital platform  is availThe participants from different health system levels were interviewed during the study’s first phase. The study participants comprised 30 frontline workers from the field, 46 staff members from government and private health facilities, 28 from the district level, and 22 from state-level cadres.The mean age of the 126 participants was 38.4 (SD 8.9) years and the average work experience was 8.9 years , with the maximum level of experience at the district and state levels. The district and state program functionaries are mostly supervisory cadres who are promoted from the cadres of lower levels. Approximately half of the respondents were women, one-third of whom had completed higher education with a bachelor’s degree or above.Approximately 83% of the health workers indicated the need for refresher trainings. The themes generated from the analysis of the transcripts of in-depth interviews are shown in The need for knowledge on the management of patients with TB was not assessed at the time of the program implementation plan. Since many new updates and the last formal training took place a few years ago, each cadre of the NTEP staff urged refresher training. A few frontline and health care facility staff were recently appointed without orientation or training. There was an ultimate need to create a planned training calendar based on the needs assessment.Refresher training is important. New things are updated in the program. If the regimen changed and we are not aware, then we administer the old regimen only, so refresher training is required.Field worker, TB health visitor with 2 years of experienceModules for all cadres need to be developed; currently, modules of frontline workers do not contain newer updates on diagnostics and regimen. The delay in universal drug susceptibility testing leads to poor management of TB patients.Multipurpose health worker, Ranchi, JharkhandI am newly joined here and do not know how to manage a drug-resistant TB patient. Also, whenever extrapulmonary TB patients come, I refer them to a higher center due to lack of knowledge on extrapulmonary TB patients.Medical officer, peripheral health institution, Gandhinagar, GujaratFor each stage of the TB care cascade, the NTEP has several interventions with specific protocols for providing care. Although health institutions have paper copies of these guidelines, a digital solution with easy navigation and a ready reckoner format would help medical personnel to take proper actions when dealing with patients with specific problems.Training needed for different diagnostic algorithms like pulmonary TB, extrapulmonary TB, pediatric TB, drug-resistant TB, and programmatic management of drug-resistant TB patients is required for medical officers. Refresher training for all health staff specific for programmatic management of drug-resistant TB guidelines on every yearly basis is required due to frequent changes in drug regimens.Medical officer, health facility, GujaratMany patients were not put on the right regimen due to knowledge gaps in diagnostic algorithms, and the delay happened in the treatment care cascade. Decision-making content and cross-checking of knowledge in the form of periodic assessment can be helpful.Private pulmonologist, JharkhandThe NTEP has undergone many newer updates since implementation of the National Strategic Plan 2017-25, with the introduction of injection-free regimens and newer drugs such as bedaquiline and delamanid, along with newer guidelines of preventive treatment for TB infection (Programmatic Management of Tuberculosis Preventive Treatment) .We have issued office orders based on communication received from the Central TB Division, Government of India. We issued to the districts and districts issued to blocks and health facilities. Still, many staff do not receive the communication due to their absence on the day of orientation or longer leaves for other personal commitments.Senior medical officer, State TB Training and Demonstration Center, GujaratWe call all the staff members at the health facility whenever we receive the office orders on newer guidelines or instruction for any activity, but not all ASHAs, auxiliary nurse midwives, and male health workers remain present due to their area work. During the COVID-19 pandemic, it was difficult to conduct any meetings or sensitize them to newer updates on any program, not just the TB program.Medical officer, health facility, JharkhandThe program guidelines, patient management protocols, repository of all government orders, and demand generation resource materials are available on the national website of the NTEP. During the interviews, it was observed that very few of the participants were using the online platform due to the time taken to search. Moreover, health staff had to go through several pages of guidelines to find a specific component they were looking for.There are so many pages in programmatic management of drug-resistant TB guidelines. If I want to read or refer to any specific sections it is difficult to search between chapters.Senior treatment supervisor, JharkhandIt is difficult for me to read all the guidelines as I have joined recently. Very few materials are available in Hindi, and I find it difficult to manage a TB patient without the trainings.Male health worker from the field, JharkhandMost of the time, we get PowerPoint slides or PDF files to read the protocol or guidelines. I find it difficult to go through all the material. A one-stop solution would be helpful with videos also.Senior TB treatment supervisor, GujaratThrough interviews, we further found that increasing training coverage to meet the needs of health personnel in capacity building is financially constrained. The infrastructure and funding in place would not be sufficient to train the entire workforce annually.We have limited resources in terms of infrastructure and budget to cover all staff for 5-7 days of modular training of NTEP. We also need finance to create the state-specific resource material in vernacular language and training materials to give to the trainees.District TB officer, GujaratWe are not training private sector staff. We do not have that much money in the budget. We orient the doctors, and it is their responsibility to train them, but we provide resource materials in soft copies.Block medical officer, GujaratThis phase’s consultative procedure included a series of formal and informal discussions with various stakeholders, including frontline workers. The early discussion exercises resulted in agreement on the need for a digital tool in the shape of a digital health app that boosts the capability of health cadres and supports and helps them with TB diagnosis and treatment concerns. To develop the digital solutions, different areas were discussed so as to build a prototype and then test it with health care providers. The end result was the development of Ni-kshay SETU that provides easy access to the most recent guidelines in the local languages of Gujarati, Hindi, and English, as well as practical answers to operational questions that health care workers frequently encounter in their day-to-day work .Initially, a ready reckoner version of evidence-based content from current NTEP guidelines was incorporated into the digital modules, and its compliance with the guidelines was verified by experts. The landscaping of available knowledge and TB control program apps such as Ni-kshay , TB AaroFrom October to December 2021, a beta version of the app was shared for input on user interface design and to identify key app components. Based on the feedback, the content of the app was evaluated and prioritized. The design and content of the app were put to the test by a variety of cadres, including field staff, medical officers at peripheral health institutions, community health officers, senior treatment supervisors, senior TB laboratory supervisors, private doctors, and general health care personnel.Finally, the Ni-kshay SETU app was developed for web, iOS, and Android platforms focusing on the core components of the management of patients with TB during the care cascade. The core components are how to identify a patient with TB, how to manage the patient, and where to refer a patient, along with resource materials and assessment sections. The app interface is shown in Digital learning platform as a mobile appPatient-centric diagnostic and treatment algorithm to guide users for management of patients with tuberculosis (TB)Cadre-specific modules in the form of ready reckoner content with easy navigationAccess to a digital repository with audio-visual resource materials; option to upload state-specific resource materials in local languagesArtificial intelligence and voice-assisted chatbot in providing specific answers in user-targeted query optionsAssessment sections for all health cadres and specific topics of patient managementBackend analytical dashboard to monitor the usage of the content and to identify training needsMultiple Indian language support for health care workers from varied geographical locationsThe National Strategic Plan 2017-25 was developed to reduce the burden of TB and eliminate the disease by 2025. This plan focuses on four critical strategic pillars: “Detect-Treat-Prevent-Build.” With “Build” as one of the strategic pillars, major attention has been paid to developing the ability of human resources and enhancing the enabling policies . There aThis study emphasizes the need for health care staff capacity-building and the availability of an easy-to-access solution to solve the issues they confront when managing patients with TB. The lack of updates on the newly released NTEP guidelines indirectly prolongs delays across the TB care cascades . This gaVarious studies highlighted that mobile apps, or digital health solutions, improve people’s health worldwide . Health This study focused on the need for health care professionals to have a quick reckoner and decision-support tool that is easily accessible and that enables them to take various actions based on the issues and complexity they run into when implementing the NTEP, even in remote stations. The app was created to meet the requirements of the health care workers to manage patients with TB based on the conclusions and observations made during the qualitative interviews. Health care workers may take swift action and have access to updated content at any time and location with the help of Ni-kshay SETU. Additionally, this app offers material in multiple languages that health care personnel may find useful. Along with a resource library with government office orders, guidelines, presentations on clinical standards, and easy-to-learn videos. Ni-kshay SETU also offers content filtering based on cadre and a selection of chatbot questions to help health care staff with their issues.This study thus offers a platform for the development of more operation research to address capacity-building issues and determine the optimum approach to include digital health learning apps into current implementation frameworks. More research will be performed to determine the impact of Ni-kshay SETU on the TB care cascade of patients by enhancing the knowledge of health care workers.The aim of this study was to gain understanding of the expectations placed on medical personnel working for the NTEP. The study’s restricted geographic scope makes it difficult to generalize the findings. The health staff highlighted a ready reckoner tool as a core requirement because the program is frequently altered depending on technical inputs and field observations. However, this effort represents the first creation of an app with consideration of the needs of the community personnel working with the TB control program. Therefore, this research serves as a crucial tool for planning and developing the app as well as for building modules and app-related material. Additionally, it is recommended to integrate such an app with multiple platforms to offer health professionals a uniform user experience.Health staff represent the primary contact point for a patient with TB. Therefore, it is critical to place our hope on the ability of health care workers to effectively comprehend the technical queries of the program. An easily accessible source of information can direct health care personnel to take the appropriate steps to manage patients with TB at their level. The recently developed Ni-kshay SETU app provides an opportunistic platform to strengthen the health workforce and achieve the target of TB elimination by 2025. The vision of this app is not only to strengthen capacity but also to provide a case for low-cost digital capacity building in resource-constrained settings toward developing a resilient health system.


Optical coherence tomography (OCT) is used extensively in imaging the cornea in health and disease. OCT delineates interfaces of differing refractive indices, which often but not always correspond to histological features of the tissue. Interpretation of images in the context of histology can be difficult. Some tissues or substances, like cyanoacrylate glue on the cornea, obstruct the passage of light and cast shadows obscuring all features deeper to the obstruction .We report a clinical sign, seen on corneal OCT images, which is consistently present in relation to corneal vascularization. Five patients with extensive corneal vascularization secondary to infectious keratitis (2), limbal stem cell deficiency (LSCD) (2) and interstitial keratitis (1) were examined clinically by slit lamp examination and by OCT as part of their routine assessment. The infectious keratitis cases and the interstitial keratitis case were in the healing stage after intensive antibiotic and topical steroid treatment respectively. The LSCD case was 2 years post chemical injury.Anterior segment (AS) OCT was carried out with a Heidelberg Spectralis  with the light beam at right angles to the major trunks of the corneal vessels giving cross-sectional images of the cornea. Twenty-one scans from limbus to the center of the superior and inferior halves, of the cornea were obtained. All forty-two scans were examined individually for each patient and correlated with the slit lamp examination and images using . Each major vascular trunk (400 µ–1200 µ), both afferent and efferent, with an active circulation obstructed the passage of light completely. A dark shadow, starting from the depth of location of the vessels and extending the entire thickness of the cornea posterior to the location, was seen as a straight line on the OCT scan. The shadow was well delineated as a hypo-reflective stripe in the general hyper-reflective background of the entire image. The width of the shadow corresponded to the width of the vessel that cast the shadow. In eyes with extensive vascularization with multiple vessels, several vertical lines of the shadows cast were visible in a single scan, giving it the appearance of a bar code, hence the descriptor, the ‘bar code sign’ is proposed for this appearance  and veins (efferent) have different vessel-wall structures, this is not the same as afferents and efferents of corneal neovascularization. As both type of vessels produced an equally dense shadow, it is likely that the obstruction to the passage of light was by the column of circulating blood in the vessels rather than the vessel wall. Moreover, ghost vessels that did not contain a blood column, did not cast a shadow. The corneal stroma has a rich network of nerves, especially anteriorly. These were not apparent on OCT imaging though in-vivo confocal microscopy imaging and whole mount staining of nerves of diseased corneas show extensive thickening of nerves , 3. The


The efficient computation of viewpoints for solving vision tasks comprising multi-features (regions of interest) represents a common challenge that any robot vision system (RVS) using range sensors faces. The characterization of valid and robust viewpoints is even more complex within real applications that require the consideration of various system constraints and model uncertainties. Hence, to address some of the challenges, our previous work outlined the computation of valid viewpoints as a geometrical problem and proposed feature-based constrained spaces ( The number of applications requiring machine vision capabilities  has rapidly increased within the research and industry over the last decade ,2. DepenIn an attempt to propose an efficient and generic framework to tackle the VPP, this publication extends the concept of feature-based constrained spaces :Problem 1.What is the minimum number of viewpoints to acquire a set of features considering different viewpoint constraints?Magaña et al.  focused Although  delivereFor these reasons, the present paper first extends the concept of In a second step, the present work addresses the second subproblem of the VPP, i.e., the SCP, and introduces a viewpoint plan strategy in In the last model-based and non-model-based approaches. Since our framework falls under the first category, this section provides a more comprehensive overview of the related research following model-based approaches.The VPP has been the focus of the research over the last three decades within a wide range of vision tasks that demand the computation of generalized viewpoints. A broad overview of the overall progress, challenges, and applications of the VPP is provided within various surveys ,6,7,8,9.synthesis or sampling-based approaches. On the one hand, synthesis approaches consider first the characterization of a continuous or discrete solution space. On the other hand, sampling-based techniques generate and evaluate viewpoints based on objective functions without the need to span a search space.Model-based methods require minimal spatial information from the features, e.g., its position and orientation, can be categorized as The synthesis of solution spaces  is available, this knowledge should be used in the most effective and analytical manner. Furthermore, in this study, it is assumed that each viewpoint constraint should be spatially modeled in the special Euclidean (6D) aligned to a synthesis approach see . This caViewpoint planning strategy: Taking into account the modularization of the VPP and the characterization of Our literature review revealed various ways of characterizing solution spaces to identify valid viewpoints that satisfy the VPP, either explicitly or implicitly. Implicit methods incorporating sampling techniques can be highly advantageous and computationally efficient, especially in straightforward scenarios with fewer constraints. However, modeling uncertainties to compensate for robust solutions in complex applications that consider multiple features and constraints poses a more challenging task when using objective functions. That is mainly because the validation of objective functions must be explicitly proofed for each computed viewpoint, and no alternative viewpoints are initially proposed. This point is particularly crucial in real-world applications, where modeling uncertainties cannot be ignored, and robust approaches for compensating for these uncertainties are necessary. The difficulties of handling the VPP by discretizing the valid viewpoint space can be mitigated by using analytical modeling to establish the validity of constraints in special Euclidean explicitly. Therefore, an approach that proposes modeling every constraint as a solution space has the potential to address the VPP explicitly. However, addressing the problem this way requires an extensive analysis of the constraints and how they can be spatially modeled. While our previous work  addresseTo the best of our knowledge, no other works have utilized a feature-based approach and combined multiple infinite spaces to compute valid viewpoints while considering several constraints. Furthermore, no generic strategies can be employed in conjunction with The outline of this research is shown in Finally, This section provides a brief overview of the most elementary components that build an RVS. A more exhaustive description of the models of all components is given in . Figure s)  is defined as a self-contained acquisition device comprising at least two imaging devices A sensor Is:=The resulting The sensor’s kinematic model considers the following frames: z-axis) A basic requirement for detecting a surface point is that the relative angle between a sensor and a surface is within the limits of the specific maximum angle of a sensor. The maximal incidence angle is normally provided by the sensor’s manufacturer. This incidence angle, denoted as Furthermore, the rotation of the sensor around the optical axis is given by the Euler angle o) domain  holds all features to be captured. Since the framework introduced in this publication can be categorized as a feature-based approach, the object may have an arbitrary surface topology. However, if occlusion constraints are taken into account, then a surface model of the object must be considered if the object itself occludes the features.The object (f)  can be fully specified by its kinematic and geometric parameters, i.e., frame A feature  for positioning the sensor at the selected viewpoint candidates. Since the viewpoint’s validity may depend on the robot kinematic,  considerv. The present report regards a feature-centered formulation and defines a viewpoint as a triple of the following core elements: a 6D sensor pose In the literature, there seems to be no general definition of a viewpoint The set of viewpoint constraints F P that holds a finite number of k viewpointsn features from F satisfying all viewpoint constraints A vision task is defined by the set of features We are convinced that a multi-stage formulation of the VPP can reduce its overall complexity and enable more efficient solutions. Therefore, in our first study , we propMagaña et al.  attributThe generation of viewpoints for acquiring one or multiple features can be treated as an isolated subproblem of the VPP. Hence, our previous study  focused The present study first summarizes the formulation of the VGP in the context of single-feature vision tasks . Then, aThe concept of  the VGP :Problem 2.Which is the f, considering a set of viewpoint constraints The mathematical definition of the up SO(3) :(5)Cf=R3i Moreover, let the formulation of An abstract representation of the Although the concept of feature,  did not Problem 3.Which is the G. As its counterpart, i.e., G considering a set of viewpoint constraints The Equation :(7)CG=⋂G.If a The k viewpoints to capture all n features; this formulation was initially introduced in Problem 1. On the other hand, the SCP can be posed as a decision problem:In general, the SCP may be formulated as an optimization problem or a decision problem. On the one hand, the optimization definition strives to find the minimal number of Problem 4.Are k viewpoints sufficient to acquire a set of features F?Although any approach addressing the VPP should prioritize the minimization of viewpoints, in our view, an optimization formulation may appear impractical and even ineffective in real applications regarding model uncertainties and feature-rich scenarios. Hence, for the benefit of pragmatism and as other authors, e.g., ,16,18, hk iteratively. In this case, a first attempt is made to solve the problem considering an initial value, e.g., k viewpoints are not sufficient to acquire F, then k is increased by one until there are enough viewpoints to acquire all features.A simple solution for Problem 4 is given by finding At this point, the challenge and motivation of the first subproblem of the VPP, i.e., the VGP, arises: how the validity of viewpoints can be efficiently and effectively assessed. A solution to this problem was comprehensively addressed using aces cf. . Hence, Having addressed the individual subproblems of the VPP, its reformulation can then be posed aligned to a decision formulation of the SCP and the concept Problem 5.Are k k potential feature clusters must be addressed in the first step. The number of k feature clusters can be iteratively found following the ground idea proposed in Aligning the VPP to a decision formulation, the search for finding k feature clusters can be found, then exactly k F. Now, if all Assuming that an adequate number of potential This section describes the definition of Aligned to the formulation of problem,  demonstrf.For instance, the fundamental The ion, see  for furtAlgorithm 1 Characterization of the f.Select a sensor orientation Rotate the Reflect Position the sensor’s TCP frame at the the feature’s frame considering the sensor orientation Translate the Fixed Sensor OrientationRecalling that Although an approach to characterize duced in , we consAlthough CharacterizationAssuming that the sensor orientation is known and the feature clusters are identified, the characterization of the In the first step, all individual Equation . Figure In addition, A great deal of attention must be paid if the intersection of two VerificationTo verify the characterization of In the first step, the individual r s1 see  and the A However, The present publication poses the VPP in the framework of decision formulation problems and suggests the use of Addressing the SCP as a decision problem requires identifying feature clusters in the first step, i.e., groups of features that can potentially be acquired together based on their spatial vicinity and orientation similarity. Identifying such feature clusters can be efficiently performed using a clustering algorithm such as a centroid-based k-Means algorithm. This subsection presents a practical and efficient clustering strategy for identifying potential feature clusters. Data Preparationz-axis) considering a defined distance I denotes a First, the strategy proposed within this subsection regards a data-enhancing preprocessing step for combining feature positions and their normal vectors to simplify the search for more effective clusters. In addition to the features’ position, we assume that features having similar normal directions are more likely to be clustered together. Hence, a new observation variable is introduced for each feature Iteratively Clusteringk cluster centroids Finally, using the set of observations Recalling the approach proposed in Taking into account the imaging capabilities of the sensor, lane see .k is increased by 1. If a minimal number of clusters can be estimated beforehand, this can be given as an initial value to optimize the search process; otherwise, If any element of ondition , then k Equation  is satisRecalling the requirements to compute FormulationThe sensor orientation in x-axis and y-axis of the sensor, the swing angle provides the rotation around the z-axis.While the normal vector represents the incidence angle, i.e., the rotation around the Incidence AngleThe optimized incidence angle for a cluster can be calculated using the arithmetic mean of the normal vectors of all features of a cluster In the case that the incidence angle between the optimized orientation and a feature is greater than the maximum Equation ), then tSwing Anglez-axis.Optimizing the rotation angle around the optical axis can be particularly advantageous when the sensor frustum is asymmetrical. Hence, this subsection suggests finding the optimal swing angle using an oriented minimum bounding box (OBB) algorithm. The direction of the longest side of such a bounding box corresponds to the optimized sensor around its First, the 2D projection of all features Next, using all projected points, an OBB algorithm  can be aThe swing angle corresponds to the principal axis vector Orientation of further imaging devicesIn the context of range sensors consisting of more than one imaging device see , note thThe Integration Strategy of Having identified the number of necessary feature clusters and corresponding optimized sensor orientations, the necessary This study extends the strategy from  to consiMoreover, the present strategy considers the decimation of the resulting Occlusion-Free According to , C-spaceBased on this insight and taking into account that this step must be repeated multiple times for all Strategy against invalid Finally, it should be noted that the feature clusters and optimized sensor orientations should be considered as an initial and plausible solution to capture all features. However, the validity of a The intersection of two consecutive Algorithm 2 Characterization of j feature cluster Select the t imaging device of the sensor Select the Consider the sensor orientation Compute all j Compute the Compute all j Recompute the Repeat Steps 3–7 for all imaging devices Compute the Steps 2–11 are repeated for each cluster Having computed all required In the simplest case, any vertex of the This section outlined a generic viewpoint planning strategy to solve the VPP based on the formulation of the SCP as a decision problem and This section comprehensively analyzes the usability of The framework presented within this publication was utilized for automating the dimensional metrology inspection of a car door comprising up to 670 features using the industrial robot vision system AIBox from ZEISS. The AIBox is an integrated industrial RVS manufactured by ZEISS, equipped with a structured light sensor (ZEISS Comet PRO AE), a six-axis industrial robot (Fanuc M20ia), and a rotary table for mounting an inspection object. The imaging parameters of the imaging sensor and structured light projector are given in To thoroughly evaluate the strategy and algorithms presented in this publication, 15 different inspection tasks were considered. The tasks comprise combinations of different features from both door sides and viewpoint constraints. The left columns of Door Side: To evaluate the usability of the present framework in an industrial context, a car door was used as the probing object. Due to their topological complexity, feature density, and variability, car doors are well-known benchmark workpieces for evaluating metrology tasks and their automation.Number and Type of Features: The scalability was evaluated using inspection tasks with different numbers and types (points and circles) of features.Viewpoint Constraints: To analyze the efficacy and efficiency of the overall strategy, vision tasks with different viewpoint constraints were designed. All vision tasks regarded at least the most elementary viewpoint constraints Two metrics were designed to properly evaluate the computed viewpoint plans and to compare and benchmark the obtained results.Measurability Indexn. The measurability index is given as follows:To properly quantify the validity of the computed To assess the measurability of a single feature, we considered a qualitative The qualitative function assesses the following two conditions.A feature Both sensor and projector have free sight to the feature.If both conditions are fulfilled, the feature is considered to be successfully acquired.The validity of each feature was further qualified based on the resulting 3D measurement, i.e., the point cloud. This metric counts the number of acquired points within a defined search radius around a feature. If there exist more points than a specified threshold, the feature can be considered to be valid.It needs to be noted that the proper evaluation of this condition requires that the measurements are perfectly aligned in the same coordinate system as the features and that the successful acquisition of surface points is guaranteed if all regarded constraints Computational EfficiencyTo provide a comprehensive analysis of the computational efficiency of the viewpoint planning strategy, the computation times of the most relevant steps were estimated:k feature clusters and corresponding optimized sensor orientations,computation time for computing the necessary computation time to characterize all individual k computation time to characterize all total computation time of the vision task, corresponds to the sum of the times mentioned above.The evaluation tests were developed using the trimesh library  and openThe viewpoint planning framework was developed based on the Robot Operating System (ROS) , which wMoreover, the clustering was performed using the k-Means algorithm of the Sci-Kit library, using the Lloyd implementation . Due to u et al.  was util library .In the first step, the required Equation ), which Equation . FurtherMeasurabilityIn the first step, the qualitative evaluation of all viewpoint plans was performed based on the previously introduced metrics. As expected, the qualitative evaluation shows very encouraging results, with an average measurability index above On the one hand, these encouraging results confirm the validity and applicability of the viewpoint planning strategy using Occlusion: All failed qualitative evaluations and the decrease in the measurability score if occlusion constraints were regarded can be attributed to the nonexistence of an occlusion-free space for the computed Furthermore, the failed evaluation of most features lying on the inside of the door was occasioned by occlusion with the door itself, which was initially neglected as an occluding object. However, an empirical analysis of some failed viewpoints showed that a positive evaluation could be achieved by recomputing the Missing points and misalignment: The quantitative evaluation of some individual viewpoints showed discrepancies between the simulation and the real measurements. These differences can be easily explained considering the requirements of the quantitative evaluation strategy proposed in Computational EfficiencyThe computational efficiency overview from It can be observed that the feature clustering and optimization of the sensor orientation can be regarded as the most efficient step of the strategy and represent, on average, less than 10% of the whole planning process. The experiments show the efficiency of the k-Means algorithm for such tasks, agreeing with the previous findings from .The vision tasks that only incorporate the fundamental constraints Moreover, neglecting occlusion constraints, the average computation time for the characterization of one ices. In  the compThe computation of the tion cf. , the timDeterminismFinally, we selected three inspection tasks  are perpendicular to the x-axis of the feature’s origin. The geometrical length of these extra features corresponds to the height of the cylinders. An overview of the frames of all features corresponding to one cylinder are shown in Features: The measuring object comprises three cylinders with different positions see . The feaSensors and Acquisition of Surface Points: It is assumed that the LLS only moves in a straight line in the CMM’s workspace with a fixed sensor orientation. For this reason, we assume that all feature surface points can be acquired with a single scanning trajectory as long as the incidence angle constraint between the surface points and the sensor holds.Viewpoint Constraints: Equally to other vision systems, the successful acquisition of surface points depends on the compliance of some geometric viewpoint constraints, such as the imaging capabilities of the LLS (z-axis, see Under consideration of the previously mentioned assumptions and modification of the domain models, the necessary z, Considering the minimal established viewpoint constraints, the viewpoint planning strategy yielded three The computation time of the whole strategy corresponded to Furthermore, an exemplary representation of the sensor placement of the resulting scanning trajectories of the third It should be noted that some surface points could not be successfully acquired for some single extreme scanning trajectories, e.g., the scans 1 and 2 from Furthermore, the measurements of all scanning trajectories are depicted in A more comprehensive evaluation of the strengths and limitations of the viewpoint planning strategy is discussed in the context of the main goals of this publication:On the one hand, the effectiveness of the computed viewpoint plans and chosen sensor poses showed an encouraging average measurability satisfiability of over 95% for all regarded vision tasks. It was demonstrated that by considering more viewpoint constraints, the efficacy of the viewpoint plans could be increased towards full measurability. On the other hand, in some cases, a complete measurability could not be achieved due to the occlusion limitations of the planning strategy. Although the present work considered occlusion constraints and the validity of occlusion-free Moreover, although the ested in .Furthermore, most of the selected viewpoints within the The comprehensive analysis of the computational complexity demonstrated that most view plans could be computed in near linear time. Due to the complexity of the developed software framework and dependency on external libraries, a more detailed computational analysis is needed to verify the complexity of the strategy and Moreover, the estimated computational times also showed that if occlusion constraints are regarded, the complexity of the overall strategy increases considerably and depends strongly on the complexity of the considered surface models. Hence, the future research should be devoted to a more efficient characterization and computation of the occlusion spaces.Furthermore, in terms of overall planning efficiency, the further studies should concentrate on the extension of the present viewpoint planning strategy for considering the proper combination of This study demonstrated that the usability of However, further work remains to be carried out to properly evaluate the use of The VPP is a multi-dimensional and challenging problem that any vision task demanding the computation of multiple and valid viewpoints must consider. Based on our literature review, the VPP is still regarded as a complex and unsolved challenge, lacking a generic and efficient framework for computing multiple viewpoints within feature-based applications.Towards tackling the VPP, the present work proposes its modularization and addresses its subproblems separately, i.e., the VGP and the SCP. First, based on our previous work , the preThe key contributions and advantages of a viewpoint planning strategy based on Mathematical and generic formulation of the VPP to ease the transferability and promote the extensibility of the framework for diverse vision systems and tasks.Synthesis of -analytical, model-based, and closed-form solutions,-simple characterization based on constructive solid geometry (-infinite solutions for the seamless compensation of model uncertainties.Generic and modular viewpoint planning strategy, which can be adapted to diverse vision tasks, systems, and constraints.The outlined viewpoint strategy can be categorized as a model-based approach requiring minimal a priori knowledge about the sensor’s frustum model and the location and geometry of the features to be acquired. However, the present framework does not consider a stringent definition of features. Hence, the future work should evaluate its usability and adaptability for diverse vision tasks.Our previous work  introducurements . On the Although our experimental results demonstrated encouraging results regarding the efficacy and efficiency of the present framework, further studies should concentrate on the definition of a benchmark scenario and standardized evaluation metrics that facilitate a direct and more comprehensive evaluation between diverse approaches. Due to the nature of the approach presented, which suggests an explicit characterization of the domain models and constraints, a non-negligible effort to implement and parameterize the models as proposed in this research should be considered.Despite the mentioned limitations, we are convinced that the outlined viewpoint planning strategy based on


Inserting IUDs during cesarean section reduces the need for more manipulation and discomfort. The current conventional manual technique for IUD insertion during cesarean section is not standardized with many modifications and high rates of expulsion, displacement, missed threads, and discontinuation. This study aims to find a standard technique for IUD insertion during cesarean section with the least possible problems, especially displacement and missed threads.A randomized controlled study was conducted at Kasr Al-Ainy Maternity Hospital, Cairo University, Egypt. The study was performed over 12 months, from September 2020 to September 2021. Two groups of patients were selected; each group included 420 patients with a desire for IUD insertion during cesarean section. Group (A) (Control group) was subjected to a post-placental intrauterine device (Copper T380) during cesarean section using a conventional manual method; Group (B) (Study group): the IUD (Copper T380) was placed at the top of the uterine fundus using a new technique .p-value < 0.05. There was no significant statistical difference in the term of duration of surgery.There was a significant statistical difference between the two groups regarding displacement of the IUDs at the end of puerperium, at 6 months, non-visibility of IUD threads, and continuation of use with The new technique of post-placental IUD insertion can be the standard technique of intra-cesarean section IUD insertion as it is associated with more favorable outcomes among the included women in the form of lower incidence of IUD displacement, non-visibility of IUD threads, and higher rates of continuation without increasing the duration of surgery as compared with the conventional manual technique.ClinicalTrial.gov ID: NCT05788354, registration date: 28/03/2023 (retrospectively registered).The online version contains supplementary material available at 10.1186/s12884-023-05777-1. In Egypt, an intrauterine contraceptive device (IUD) is commonly used more than any other kind of contraceptive . DespiteThe most upsetting risk is the displacement of the IUD, particularly if it occurs extra-uterine. Displacement of IUDs raises the possibility of unintended pregnancy and the complications of possible surgical interventions. To decrease the possibility of displacement, it is crucial to place IUDs at the right time and with the right procedure . The besMoreover, women now have a strong desire to start using contraceptives. The current conventional manual technique for IUD insertion during cesarean section is not standardized with many modifications and variable rates of displacement and expulsion 5.23–22%), missed threads 0–72%), and discontinuation (0–15%) [.23–22%, 2%, and dThis is a prospective randomized controlled study that was conducted to compare between the conventional  technique of post-placental IUD insertion and a new technique  for IUD insertion during cesarean section regarding side effects and complications.This study was performed at the Department of Obstetrics and Gynecology, Kasr Al-Ainy Hospital, Cairo University, Egypt. The study was conducted over 12 months, from September 2020 to September 2021.The study included 840 pregnant women to whom IUD was planned to be inserted during cesarean section upon their requests. The cases were randomly divided into two equal groups according to the technique of insertion as follows: Group A (Control group): Included 420 pregnant women where the IUD was placed at the top of the uterine fundus manually (Copper T380) using the conventional method of post placental IUD insertion; Group B (Study group): Included 420 pregnant women where the IUD was placed at the top of the uterine fundus (Copper T380) using the new technique of IUD insertion.We included pregnant women whose age was between 18-45 years old and attending for elective or emergency cesarean section. The patients desired immediate IUD insertion.We excluded women with the upper segment or classical cesarean scar, cesarean for placenta previa or placenta accreta, and evident infections during cesarean section as chorioamnionitis, uterine anomalies, uterine myomas, and bleeding tendency.Participants were randomly allocated to the two groups using opaque envelopes. Then, the envelopes were opened sequentially immediately before IUD insertion to maintain concealment. After that, the randomization list was generated using a “computer software” by a statistician not otherwise included in this study. The participant’s allocation is based on the 1:1 ratio. Then, the investigators enrolled participants and assigned them to interventions. A record of the type of chosen intervention and the insertion method was kept to facilitate analyses based on the intention to treat by protocol. Finally, participants were blinded to the group allocation.Written informed consent was obtained from all participants before inclusion in the study, explaining the value of the study plus the procedures that were commenced.The study design was approved by the Research Scientific Ethical Committee (RSEC), Department of Obstetrics and Gynecology, Faculty of Medicine, Cairo University, Egypt (reference number I20015). Confidentiality and personal privacy were respected at all levels of the study. Patients felt free to withdraw from the study at any time without any consequences. The collected data were not and will not be used for other purposes. All methods were carried out per relevant institutional guidelines and regulations.A lower-segment cesarean section was carried out for all participants after a full clinical assessment. Following placental delivery Copper T380 IUDs were placed in the uterine cavity as follows:First, we performed time out and verified that there were no contraindications to IUD placement; Second, after package opening, we removed the IUD from the introducer and trimmed IUD threads to 12 cm; Third, we grasped the IUD firmly along the stem of the device; Fourth, we stabilized the uterus using the non-dominant hand or with the aid of an assistant and advanced the IUD through the hysterotomy to the fundus; Fifth, we removed the hand and directed the IUD threads manually into the cervix; and Finally, we closed the uterine incision, took care not to incorporate the IUD threads.In our new technique, we applied the same idea of the withdrawal technique used for IUD insertion in gynecology. In this technique, the intoducer is used to push the IUD unfolded arms (after its release) to place it high up in the uterine fundus and withdraw it without pulling the IUD with it downwards. This is because the diameter of the introducer (3.8 mm) is wider than the diameter of the IUD stem (3 mm), so the introducer is not grasping on the IUD stem. In our new technique, the arms of the IUD remain unfolded through the steps of the technique.First, we performed time out and verified that there were no contraindications to IUD placement; Second, after the package opening, we removed IUD from the package and trimmed the IUD introducer with the IUD threads inside to 12 cm after the removal of the distance marker (The collar or the blue flange) of the introducer ; Third, we held the uterus, stabilized it with the non-dominant hand, and inserted the introducer with the IUD threads inside first downwards through the cervical canal before pushing it up to put it firmly against the endometrium of the uterine fundus. Then, we pulled it gently down through the cervical canal to the vagina while pressing on the fundus with the non-dominant hand, thus ensuring that the IUD is kept in the fundus and that the IUD threads are in the cervical canal. The pulling of the introducer will not withdraw the IUD as it is now grasped by the non-dominant hand. Even if the non-dominant hand is grasping both the IUD and the introducer, the introducer will not pull on the IUD downwards with it as it does not grasp on it. Finally, we closed the uterine incision, and took care not to incorporate the introducer or the threads. Next, we removed the introducer gently manually from the vagina after the closure of the skin and ceiling of the wound  by an independent assessor at the end of puerperium and six months following up the distance from the top of the uterine cavity to the IUD, which should be < 3 mm).◦Missed or non-visibility of IUD threads by speculum examination (at the end of puerperium and six months).Discontinuation of the method (at six months) by questionnaire assessment.Duration of surgery from the skin incision till the closure of skin wound .Follow up for:p-value), and the results were explained as follows: non-significant if the p-value is > 0.05, significant if the p-value is ≤ 0.05, and highly significant if the p-value < 0.001.The collected data were handled and studied using SPSS  version 27. Mean (X) and standard deviation (SD) were used for normally distributed data, while for skewed data, median (Med) and interquartile range (IQR) were used. For qualitative data, the frequency with percentage (%) was used. Analytical or inferential statistics included Fisher’s Exact Test: It was used to compare two or more groups regarding one qualitative variable. It was used instead of Chi-Square (χ2) test when the assumption that at least 80% of the expected frequencies are greater than five was violated. Independent samples t-test was used for continuous data to test for significant differences between two normally distributed groups. Assumptions of normality in each group and homogeneity of variances were verified using the Shapiro-Wilk test and Levine’s test, respectively. The Mann–Whitney U test was used for continuous data to test for significant differences between two abnormally distributed groups. Significant test results are quoted as two-tailed probabilities. For all the tests mentioned above, the level of significance was tested, expressed as the probability of : The conventional post-placental IUD insertion technique (Group A), and the new technique (Group B). The excluded cases due to lost follow-up were equal in the two groups (26), and finally, 394 cases in each group were analyzed  to maximize the usage of trustworthy, efficient, and long-lasting contraceptive techniques, especially in countries with high populations and at a time when women are highly motivated for contraception –11.Till now, there is no standardized technique for IUD insertion during cesarean section. The conventional technique of IUD insertion during cesarean section, as described in previous studies, is based on the manual placement of the IUD in the uterine fundus and manual guide of the IUD threads through the cervix –11. In sOur study compared the conventional manual technique to a new technique . This is the first study that describes and outlines this technique in detail and its advantage compared to the conventional post-placental manual IUD insertion technique.The rationale of our technique is to use the introducer to ensure placing the IUD in the uterine fundus and ensuring that its threads pass through the cervix to the vagina. The conventional manual insertion technique of grasping the IUD from the stem does not ensure that the arms of the IUD are firmly in contact with the uterine fundus, while pushing the IUD unfolded arms with introducer up to the fundus ensures that. Additionally, we must note that pushing the IUD differs from grasping and releasing it. Putting a grasped IUD in the uterine fundus may be followed by some degree of pulling the IUD downward during the withdrawal of the grasping hand (or even a grasping instrument) due to the narrowness of the available cavity that creates some negative pressure and due to some inability to completely ungrasp the IUD. In contrast, withdrawal of the introducer will not be followed by pulling forces to the IUD downwards as the introducer now has no attachment to the IUD, as usually happens in routine IUD insertion withdrawal techniques used in gynecology.In another study, they used the introducer during the insertion technique, but they did not trim it or trim the threads and they put the IUD first in the fundus before passing it through the cervix. We can expect that they have faced difficulty in passing the introducer through the cervix as in this way as the length of the uterine cavity may not allow easily for the entry of the whole introducer before pushing it through the cervix, and that they faced resistance by the posterior vaginal wall in case the cervix is directed posterior. Furthermore, in this study, they compared intra-cesarean insertion with interval insertion .IUD displacement is the major problem of IUD usage, leading to other problems such as unwanted pregnancy, expulsion, bleeding, and uterine colics –16. In o® CS for intra-cesarean insertion by Wildemeersch and Gyne-T 380 postpartum IUD has low displacement and expulsion rates  [Fixation of the IUD after placement of it in the uterine fundus will lead to less liability for displacement . GyneFixctively) .However, we aimed to standardize a technique that can be used in developing countries with limited resources using the commonly available types of IUDs and the regular tools for IUD insertion provided with each package. Moreover, suturing and fixing the IUD to the uterus may increase the risk of bleeding, prolongation of operative time, and undue surgical difficulty. Still, there will be a need for studying the additive value of fixing the IUD to this new technique as previous studies applied fixation of the IUD with conventional manual technique.Thread visibility may be a problem with post-placental IUD placement. Non-visibility of IUD threads makes the dilemma of missed IUD difficult to extract. In our research, the new method group had a proportion of missing IUDs threads after 6 months) of 3.6%, which was statistically significantly lower than the conventional technique 9.6%). The FIGO project reported the rates of absent threads in around one-third of women (visible in two-thirds), although this was for both vaginal and cesarean births . In one .6%. The  months oIn our study, we took the continuation of the IUD usage after 6 months as a marker for acceptance, side effects, and complications. The continuation of IUD usage was higher in the new technique group than in the conventional technique group . In another study in which they used the introducer to put the IUDs in the fundus and ring forceps to guide the threads in the cervical canal, the continuity after 6 months was 83%, considering that they used different types of IUDs [Finally, we studied the duration of surgery between the two groups to know if our new technique added more significant time for the surgical procedure, and there was no significant statistical difference between the two groups as regards the duration of surgery. However, more trials of the technique with different types of IUDs and different levels of obstetricians’ training are needed.Our new technique can be the standard technique for intra-cesarean section IUD insertion as it is associated with a lower incidence of IUD displacement, non-visibility of IUD theads, and a higher rate of continuation without increasing the duration of surgery as compared with the conventional technique. In addition, the standardization of the technique is essential for future studies so that the results can be compared and reproduced. Any future new modifications of the technique should be applied to a standard technique for the reliability of the value of these modifications.Additional file 1.