Exact Number Research Articles

On the computation of robust examination timetables: methods and experimental results

AbstractWith ever-rising student numbers and an increasing shift towards more interdisciplinary study programs, the requirements for finding schedules for courses and exams become ever more complex. In real-world scenarios, the models used for calculating solutions to the course and the examination timetabling problem often must be provided to the students at the time of registration. In the field of curriculum-based course timetabling, timetables are calculated based on the structure of the study programs. For the examination timetabling problem, only a few papers focus on scheduling exams without registration data, as the requirements for exams are often more strict, or partial information is known from course registrations. In this paper we show that with the use of robustness techniques, we can also define the examination timetabling problem based on curricula. We introduce three robustness measures that address the inherent uncertainty when using the curriculum-based model. These robustness measures, along with other quality measures, are analyzed using a multi-objective simulated annealing algorithm. The results are compared on the Pareto front approximations found. We present a case study showing that, without a significant loss in solution quality, the chance is significantly reduced that rescheduling will be required after the exact numbers for the model are known.

CT and MR Imaging of Hepatocellular Carcinoma and Liver Cirrhosis

Liver masses are routinely evaluated using ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI). MRI may be used for further investigation in cases with atypical findings and difficult diagnoses. Hepatocellular carcinoma (HCC) is a common malignancy, and it is important to know the exact spread and number of HCCs, as there are numerous treatment options. In addition, it is important to know how the differentiations of HCCs are reflected on the images, and what the subtypes of HCCs look like on the images. Elastography with US and MRI is increasingly used to measure liver stiffness, and non-invasive assessment of liver fibrosis is also possible. This review describes the diagnosis of HCC on commonly used CT and MRI, and also touches on the frontiers of imaging diagnosis of liver parenchymal changes such as liver cirrhosis.

Demographics of Total Hip and Knee Arthroplasty in Nepal: An Observational Study

Introduction: Hip and knee arthroplasty surgeries are essential for treating end-stage osteoarthritis, providing significant functional improvements. Despite a global rise in these procedures, Nepal lacks a National Joint Registry, resulting in a gap in tracking the exact number of surgeries, outcomes, and complications. This study aims to address this gap regarding the demographics of hip and knee arthroplasties in Nepal.Methods: An observational study was conducted after obtaining the ethical approval from the Nepal Health Research Council (Reference number: 2024/136) with data collected from prosthesis supplier. The study included all primary hip and knee arthroplasties performed in 2022 and 2023, excluding revision cases and those requiring mega prostheses. Data analysis was performed using Microsoft Excel for descriptive statistics.Results: There were a total of 1259 surgeries, 916 (72.77%) total knee replacements were performed, with a female predominance of 741 (81.42%) and a median age of 67 years(IQR: 62-71). There were 343 (27.23%) total hip replacements surgeries of which 200 (58.31%) were done in males. Most surgeries 1148 (91.18%) occurred within the Kathmandu Valley.Conclusions: Total knee arthroplasty accounted for the majority of cases, showing a predominance of female patients with the majority of surgeries in the capital city.

Forced displacement and the healthcare workforce crisis: Venezuelan healthcare workers in Peru

Abstract Background The migration of healthcare workforces tends to be economically based benefiting high income countries, while draining lower-income countries of workers and skills. However, national instability or civil conflict may also have the effect of forcing out health workers. Few articles focus on the experiences of these types of migrants. This study aims to close a gap in the migration debate by exploring the capacity of integrating displaced healthcare workers in middle-to-low resourced health systems, using Peru as a case study. Methods The study draws on a policy analysis, statistical data and expert information from Peru. Results Peru has become the second largest Latin American destination for Venezuelan forced displaced migrants, a number of which are healthcare workers. While the exact numbers of these workers is unknown, it is estimated that 4,000 and 3,000 physicians and about 2,500 nurses and health technicians from Venezuela reside in Peru. These workers find entry into the heath system difficult due to bureaucratic and costly registration and qualification validation procedures. However, during Covid-19 the conditions were relaxed, and a large number of these workers entered the healthcare workforce. They were primarily physicians and worked in urban medical facilities, though there was some distribution across the country’s departments. This avenue to the healthcare workforce allowed the mobilisation of dormant health skills and assisted to lift density numbers. Conclusions Peru’s experiences bring into focus the potential benefits of mobilising new resources through integrating displaced healthcare worker migrants. It is too early to assess the sustainability of these policies on the country’s healthcare workforce and its Universal Health Coverage goals, yet there seem to be some positive experiences. Speakers/Panelists Tomas Zapata WHO/Europe, Copenhagen, Denmark

Quantum search algorithm for binary constant weight codes

A binary constant weight code is a type of error-correcting code with a wide range of applications. The problem of finding a binary constant weight code has long been studied as a combinatorial optimization problem in coding theory. In this paper, we propose a quantum search algorithm for binary constant weight codes. Specifically, the search problem is formulated as a polynomial binary optimization problem and Grover adaptive search is used for providing the quadratic speedup. Focusing on the inherent structure of the problem, we derive an upper bound on the minimum of the objective function value and a lower bound on the exact number of solutions. By exploiting these two bounds, we successfully reduced the constant overhead of the algorithm, although the overall query complexity remains exponential due to the NP-complete nature of the problem. In our algebraic analysis, it was found that this proposed algorithm is capable of reducing the number of required qubits, thus enhancing the feasibility. Additionally, our simulations demonstrated that it reduces the average number of classical iterations by 63% as well as the average number of total Grover rotations by 31%. The proposed approach may be useful for other quantum search algorithms and optimization problems.

Extracting efficient exact real number computation from proofs in constructive type theory

Abstract Exact real computation is an alternative to floating-point arithmetic where operations on real numbers are performed exactly, without the introduction of rounding errors. When proving the correctness of an implementation, one can focus solely on the mathematical properties of the problem without thinking about the subtleties of representing real numbers. We propose a new axiomatization of the real numbers in a dependent type theory with the goal of extracting certified exact real computation programs from constructive proofs. Our formalization differs from similar approaches, in that we formalize the reals in a conceptually similar way as some mature implementations of exact real computation. Primitive operations on reals can be extracted directly to the corresponding operations in such an implementation, producing more efficient programs. We particularly focus on the formalization of partial and nondeterministic computation, which is essential in exact real computation. We prove the soundness of our formalization with regards to the standard realizability interpretation from computable analysis and show how to relate our theory to a classical formalization of the reals. We demonstrate the feasibility of our theory by implementing it in the Coq proof assistant and present several natural examples. From the examples we have automatically extracted Haskell programs that use the exact real computation framework AERN for efficiently performing exact operations on real numbers. In experiments, the extracted programs behave similarly to native implementations in AERN in terms of running time and memory usage.

Assessing the Principle of Equitable Access versus Non-Appropriation in the Era of Mega-Constellations

In the 21st century, mega-constellations and interconnected satellite constellations deployed at various orbital altitudes, such as LEO, MEO, and GEO, with low Earth orbits (LEOs) being the most commonly used, have emerged as a trend, aiming to enhance the productivity and reduce the costs in space service delivery. The UNOOSA has noted the uncertainty in the exact number of satellites but conducted simulations based on a substantial sample, projecting a significant increase from the 2075 satellites recorded in orbit in 2018. This surge in the launch of mega-constellations poses profound challenges to existing international space laws, originally formulated with limited consideration for private space actors, who are increasingly engaging in space activities, particularly with the cost-effective utilization of mega-constellations. This study critically analyzes the compatibility of mega-constellations with the current international space laws by examining the applicability of mega-constellations concerning equitable access and the non-appropriation principle, addressing their potential occupation of substantial orbital spaces during activities, and analyzing whether the acquisition of orbital slot licenses violates these two principles. Following an in-depth analysis, this study proposes recommendations to amend the existing laws, aiming to resolve ambiguities and address emerging challenges. Recognizing the time-consuming process of amending international space laws, this study suggests practical recommendations for supplementary rules of the road, prompting reflection on the potential obsolescence of the current international space laws in the face of evolving space activities.

On Minkowski Addition of Convex Polygons in the Plane

Summary We investigate the Minkowski addition of convex polygons in the plane. It is well-known that the Minkowski addition of two planar convex polygons with m and n vertices is a convex polygon with at most m + n vertices. We give an explicit formula for calculating the exact number of vertices of the resulting polygon.

Development of two step reverse transcription droplet digital PCR (RT-ddPCR) for simultaneous identification of saliva and semen

Determination of the type of body fluids is essential for crime scene reconstruction and for improving the reliability of expert testimonies. Messenger RNA (mRNA) analysis by reverse transcription quantitative PCR (RT-qPCR) has been used in forensic genetics, particularly for body fluid identification. It is a relative quantification method that compares the Ct values of target and reference gene. Thus, the method is unsuitable for determining exact copy numbers of the target gene. To address this limitation, this study performed body fluid-specific mRNA analysis using two-step reverse transcription droplet digital PCR (RT-ddPCR), which is capable of absolute quantification. We found that RT-ddPCR was accurate and sensitive enough to detect as little as 1.5 copies/μl of complementary DNA (cDNA), making it suitable for application using casework samples. It was also highly specific for body fluids, as non-specific amplification did not occur. In addition, saliva-semen mixtures with ratios ranging from 1:50 to 50:1 were successfully identified. When comparing the results of RT-qPCR and RT-ddPCR, some samples were difficult to interpret because of the high Ct values of RT-qPCR. However, when the same samples were analyzed using RT-ddPCR, saliva and semen were distinctly identified. Thus, RT-ddPCR is useful for mixed samples (e.g., in sexual assault cases) with low amounts of DNA, which often leads to ambiguous results when using RT-qPCR. Other body fluids (e.g., vaginal fluid and menstrual blood) can also be identified by including additional markers. This study demonstrates the potential of RT-ddPCR for applications in forensic science.

Variable selection for uncertain regression models based on elastic net method

On one hand, determining the exact number of explanatory variables in uncertain regression analysis is often challenging, as real-world scenarios are interconnected. On the other hand, it’s worth noting that even when the number of variables is determined, some variables may have minimal impact on the response variable, and retaining them would only increase the complexity of the model. Therefore, variable selection methods can help eliminate variables with minimal impact to enhance the simplicity and interpretability of the model. In light of this, this paper first introduces a novel variable selection strategy based on the elastic net method to address the variable selection problem in uncertain regression models. This method not only offers the flexibility to simplify uncertain regression analysis into Lasso estimation or Ridge estimation but also exhibits extremely high efficiency in variable selection. Secondly, to address the issue of determining tuning parameters, we introduce the cross-validation method to ensure optimal model performance. Furthermore, we propose an uncertain hypothesis testing method based on imprecise observational data, which can help us assess the suitability of estimated parameters. Finally, through a series of numerical examples, we validate the feasibility and effectiveness of this method.

Punitive Operations Carried out by Lithuanian Partisans in Alytus County in 1944–1952

To compare with guerrilla wars in the 20th century in Europe, participants of Lithuanian partisan movement after the WW II were particularly involved in fighting collaborationism; they were struggling to overcome challenges related to support showed by their fellow citizens to the Soviet authorities. In the majority of cases, the punitive operations were precalculated actions, by which it was sought not to allow the Soviets to entrench deeply their authority in this country; yet, in part, it had been spontaneous responses towards substantial reforming of social relations and world view norms prevailing in Lithuania (especialy in the countryside). New norms had to comply with the bolshevist communist ideology version. In the beginning, fighting collaborationism had not been the most important part of partisan activity, yet, under conditions of increasing involvement of local people in the schemes of repressive structures (first of all, those of NKVD and MGB), the number of counter-punitive operations increased. Especially violent fight of this kind broke out in South Lithuania, first of all, in Dzūkija, as in this region, Dainava and Tauras military districts of partisans were established. Those two military districts were stronger and resisted longer to compare with other ones. It is likely that earlier, the leaders of first military groups of partisans acted spontaneously, they were following their own understanding of ethics. Although a part of them had to have access to the Order of 10th November 1944 of Headquarters of Lithuanian Freedom Army formally functioning across Lithuania. The Order contained information related to citizens behaviour concerning collaborationism. Later, the leaders of partisan military districts drafted legal acts, more or less adapted to war time conditions, regulating partisan fight tactics and methods against collaborations. Statistics collected when preparing this article shows that in 1941 – 1952, in the biggest Dzūkija county, Alytus county, Lithuanian partisans claimed the lives of more than 1 450 people (this number includes victims of clashes with the NKVD and MGB units). About 300 (21 per cent) of them were killed during mass assaults on one or several villages; later these events were named Bartholomew‘s Day Massacre. The majority of the victims were people who contributed more or less to entrenchment of Soviet system in Lithuania, although it is problematic to determine the exact number of such people, because, when investigating concrete cases, frequently, one is not able to reconstruct all circumstances of the event. Those cases when entire families were killed together with underage children are to be considered criminal offences unambiguously – no justification documents have been found concerning such actions in the written legacy of the partisans (several concerete cases demonstrate that partisan leaders considered a person of 14 years of age fully responsible for his / her actions).

Paediatric long-COVID diagnosis in school’s health unit environment

It is known that the mental health and well-being of all children and young people should be taken care of, regardless of their SARS-CoV-2 infection status. It is difficult to know the exact number of young people who need help, but in many health systems the need is likely to be greater than the resources available. Many questions about long-COVID-19 in children and adolescents <18 years of age, its prevalence, natural course, risk factors, mechanisms and consequences remain unanswered. As well as studies assessing whether vaccination reduces the risk of long-COVID-19 in children and adolescents who contract COVID-19 despite vaccination would be valuable. This paper examine the degree to which environmental elements were connected to children’s well-being during COVID-19 lockdowns and restrictions. The purpose of this study is to investigate early learning experiences in the family, childhood education and environmental elements that affect children’s social-emotional health. The results also show that there may be protective variables for kids’ mental health amid stressful situations, such the lockdowns that many families went through during the pandemic. Keywords: long-COVID, mental health in children, COVID-19, vaccinations, pandemic.

Lignin dispersion in polybutadiene rubber (BR) with different mixing parameters

There is a strong need to replace carbon black and silica as a reinforcing filler in rubber industry. Lignin is a promising option as a replacement, because of its wide availability, complex chemistry and sustainable source. Typically, the reinforcing effect of lignin is weak and one major cause is the poor dispersion of filler. In this study, typical dispersion parameters in mixing are tested in a systematic way to validate their effect on kraft lignin dispersion in polybutadiene rubber. Tested mixing variables are temperature, rotor speed, mixing time, fill ratio and shear forces. The effect of variables to dispersion are analyzed from electron microscopy images with an image analysis software. With this novel method exact number of particles and their properties could be calculated. Unlike for conventional fillers (carbon black and silica), the results show clearly that only the mixing temperature has an effect on lignin dispersion in rubber. With high mixing temperatures, dispersion and hence mechanical properties improved. The better dispersion is especially seen as decreasing number of large (>Ø 5 μm) particles. Other mixing variables did not have significant effect on dispersion and the number of large particles.

Bounding the number of limit cycles for perturbed piecewise linear Hamiltonian system

In this paper, we investigate the number of limit cycles for piecewise linear Hamiltonian system with a homoclinic loop under perturbations of piecewise smooth polynomials. By studying the number of zeros of the first order Melnikov function, we obtain the exact number of limit cycles bifurcating from the periodic annulus, which improves the results given by Liu and Xiong [13], Yang and Zhang [20].

Layanan Mobile Banking dalam Mewujudkan Kepuasan Nasabah BSI di Surabaya

This research aims to determine the quality of Bank Syariah Indonesia (BSI Mobile) mobile banking services in providing customer satisfaction at Bank Syariah Indonesia KCP Diponegoro 2 Surabaya. The research method uses a quantitative approach. The population in this research is all BSI KCP Diponegoro 2 Surabaya customers. Meanwhile, the sample in this research is some BSI KCP Diponegoro 2 Surabaya customers who use the BSI Mobile application. Considering the large population so that the exact number cannot be known and the limited time in conducting research, this research uses the Lemeshow formula with a maximum estimate of 7% and an error rate of 5% as a guideline in finding the number of samples used. So through this technique a sample of 100 respondents was obtained. Data was collected through distributing questionnaires using incidental sampling technique. The data analysis process uses simple linear regression, hypothesis testing, and coefficient of determination. The research results show that the quality of BSI Mobile services has an influence on customer satisfaction. The influence between the independent variable and the dependent variable is 79.2%, while 20.8% is influenced by other factors not included in this research. This research can help increase customer satisfaction in using the BSI Mobile application.

Pengaruh Citra Merek, Ulasan Produk dan Digital Marketing terhadap Keputusan Pembelian Kosmetik Pixy di Kota Batam

This research aims to assess the influence of brand image, product reviews, and digital marketing on purchasing decisions for Pixy cosmetics in Batam City. The utilized population consists of users who have used Pixy items, although the exact number is not yet known. The Lemeshow algorithm was used to count a total of 100 respondents using a purposive sampling strategy. Multiple linear regression models were used to test the data, along with data quality checks, classical assumption tests, influence tests, and hypothesis tests. The findings of multiple linear regression analysis show that brand image influences purchasing decisions by 59.9%. Product reviews influence 24.3% of purchasing choices. Digital marketing influences 40.9% of purchasing choices. Test results using the coefficient of determination (R2) show that brand image, product reviews and digital marketing can explain up to 70.9% of the variation in purchasing choices. Furthermore, the t test and F test show that brand image, product reviews, and digital marketing both individually and together have a good and big influence on the decision to purchase Pixy cosmetics in Batam City.

Analysis of User Experience of the CapCut Application in Generation Z for Social Media Content Using the User Experience Questionnaire Method

Purpose: In the midst of these dynamics of change, research, development and application of technology continues to be the main focus in efforts to achieve progress and efficiency in various sectors of life. Generation Z has been the primary architect of cultural and behavioral change on social media. One of the most prominent characteristics of Generation Z is their desire to create "viral" content on social media. Content created using CapCut often uses interesting video and audio effects, such as progress effects, dry effects, music effects, and so on. This application has various features that make it easier for users to create video content, such as video effects, audio and animation. This shows that generation Z tends to use the CapCut application to create and edit video content that they share on social media. This research was conducted based on a phenomenon that has recently occurred, where many generations Z want to create content on social media using the CapCut application and also from several previous studies that have been conducted which are still lacking in understanding CapCup user satisfaction as a medium for creating content for Generation Z. and from several interviews the author conducted with CapCut application users. Method: This research uses the user experience questionnaire (UEQ) method with six (6) variables, namely attractiveness, efficiency, clarity, dependability, stimulation and novelty. Dr. Martin Schrepp developed a special tool that can be used to analyze UEQ questionnaire results, namely the UEQ Data Analysis Tool. The UEQ Data Analysis Tool is in the form of an Excel application which can be obtained by downloading it directly from the official https://www.ueq-online.org/ website This study employs a quantitative research strategy. This study does not know the exact number of the population to be studied. So, the sample size was calculated using the Lemeshow formula, a survey was conducted on 96 users of the Capcut application. Result: Based on the results of the discussion regarding user experience, specifically Generation Z, in the CapCut Application using the User Experience Questionnaire (UEQ) method, conclusions can be drawn from the 6 variables in the UEQ used, the 6 variables obtained positive evaluation values, namely the Attractiveness (mean 1.177), Perspicuity variables. (mean 1.109), Efficiency (mean 1.109), Dependability (mean 1.159), Stimulation (mean 1.151) and Novelty (mean 0.763) with the highest evaluation value on the Attractiveness variable. 2. Based on the benchmark results, the values obtained for the Attractiveness variable were 1.18, Perspicuity 1.11, Efficiency 1.11, Dependability 1.16, Stimulation 1.15, and Novelty 0.76. Each variable gets an Above Average value (above the average). However, there is still potential for improvement to achieve standards of perfection desired. Users provided invaluable feedback and suggestions, highlighting the need for improvement. Novelty: This research provides 2 recommendations based on the results of evaluations using UEQ, which are expected to help in improving and improving the quality of the CapCut Application in the future.

A complete analysis of a slow–fast modified Leslie–Gower predator–prey system

In this paper, we transform a modified Leslie–Gower predator–prey system into the corresponding fast–slow version by assuming that prey reproduces much faster than predator, and then perform a complete analysis about its dynamics. More specifically, we find the necessary and sufficient conditions of the exact number (zero, one or two) of positive equilibria of the slow–fast system and its (or their) location, and then we further fully determine its (or their) dynamics under explicit conditions. Besides, by converting the slow–fast system into its slow–fast normal form, we are able to characterize its rich dynamics completely, including relaxation oscillation, singular Hopf bifurcation, canard explosion, homoclinic orbits, heteroclinic orbits and global attraction of equilibrium. Moreover, the sufficient conditions to guarantee these various rich dynamics are explicitly given, including the explicit conditions to determine whether singular Hopf bifurcation is supercritical or subcritical, which generally cannot be explicitly derived in the existing literatures. Additionally, the cyclicity of diverse canard cycles is found under explicit conditions. Of particular interest is that we show the existence and uniqueness of one canard cycle without head whose cyclicity is at most two under explicit parameters conditions. Our results complement and enrich the previous work (relaxation oscillation, and global attraction of a boundary equilibrium) about this fast–slow system. We also employ numerical simulations to illustrate our theoretical analysis.

THE EFFECTS OF TRUST, STORE IMAGE AND CONSUMER JUDGMENT ON REPEAT PURCHASES MEDIATING CONSUMER SATISFACTION VARIABLES ALFAMIDI DEMAK AREA

The purpose of this study was to determine how much influence trust, store image and consumer judgment have on repeat purchases through customer satisfaction, because Alfamid customers are the mediator of research. The population of the people taken in the study is the number of Alfamidi customers in the Demak area, the exact number of which is unknown, the sampling technique of course uses purposive sampling, where the sample size is 110 consumer representatives. The validity and reliability criteria applied in this study also use Amos free calculations for data analysis and calculation. The main conclusions of this study are that trust has a positive and significant impact on customer satisfaction; customer satisfaction is positively affected by store image and also positively affects customer satisfaction; consumer judgment is positively affected by customer satisfaction but does not significantly affect customer satisfaction. trust has a positive and significant impact in relation to repeat purchases.Store image has a positive, but not significant impact in relation to repeat purchases; consumer judgment has a positive, but not significant impact in relation to repeat purchases. Consumer satisfaction has a positive and significant impact on repeat purchase behavior. trust has a positive and significant impact on the purchase of goods through consumer satisfaction feedback, while store image has a positive and significant impact on the purchase of goods through consumer consumer feedback, and consumer judgment evaluation has a positive and significant impact on the repurchase of goods through consumer satisfaction feedback

Pengaruh Kenyamanan, Harga, dan Kualitas Produk Terhadap Kepuasan Konsumen Berbelanja di Pasar Klewer Surakarta

Klewer market is the largest textile market in the city of Solo. Klewer market is located next to the Surakarta palace. The aim of this research is to analyze the significance of the influence of comfort, price and product quality on consumer satisfaction shopping at the Surakarta Klewer market. This research uses qualitative data and quantitative data. The data source uses primary data. The population in this research is consumers who shop at the Surakarta klewer market, the exact number of which is not known. The number of samples used in this research is 120 people. The sampling technique uses purposive sampling technique. Data collection techniques use questionnaires, literature study and observation. Data analysis uses descriptive analysis, multiple linear regression test, t test, F test and coefficient of determination test. The results of the multiple linear regression analysis in this study were Y = 3,229 + 0,191 X1 + 0,165 X2 + 0,186 X3. The results of the t test show that the variables of comfort, price and product quality have a significant effect on consumer satisfaction shopping at the Klewer market in Surakarta. The results of the F test in this study have a calculated F value of 29.124 with a significance value (p, value) of 0.000 < 0.05, so Ho rejected and Ha accepted, which means the model used is correct to predict the influence of the independent variables (price convenience and product quality) on the dependent variable (consumer satisfaction). The coefficient of determination test result (R²) for this model is 0.415 or 4.15%, which means the influence of comfort, price and product quality on consumer satisfaction while the remaining 58.5% is influenced by other variables outside this research. The results of the research show that Comfort has a significant influence on consumer satisfaction shopping at the Surakarta Klewer market. Price has a significant influence on consumer satisfaction shopping at the Surakarta Klewer market. Product quality has a significant influence on consumer satisfaction shopping at the Surakarta Klewer market.