In today’s highly computerized world, data compression is a key issue to minimize the costs associated with data storage and transfer. In 2019, more than 70% of the data sent over the network were ...images. This paper analyses the feasibility of using the SVD algorithm in image compression and shows that it improves the efficiency of JPEG and JPEG2000 compression. Image matrices were decomposed using the SVD algorithm before compression. It has also been shown that as the image dimensions increase, the fraction of eigenvalues that must be used to reconstruct the image in good quality decreases. The study was carried out on a large and diverse set of images, more than 2500 images were examined. The results were analyzed based on criteria typical for the evaluation of numerical algorithms operating on matrices and image compression: compression ratio, size of compressed file, MSE, number of bad pixels, complexity, numerical stability, easiness of implementation.
Low back pain (LBP) is a problem which causes human suffering and entails costs for treatment. Chronic LBP is considered a civilization diseases in developed countries and one of the major public ...health problem worldwide. Squatting is a part of such daily activities as sitting down, standing up or lifting objects. In this study, hip, knee, and ankle joint motions during squatting are analyzed in the sagittal plane. The aim of the study was to find a relationship between the function of the lower limb during squatting and LBP incidence.
Eleven healthy subjects and eight subjects suffering from low back pain were enrolled in tes study. Participants performed squat while maintaining heel contact with the ground throughout the movement. The participants attempted to make a squat as deep as possible. Kinematic data were captured using a Vicon optical motion capture system.
The low back pain group had a greater range of motion of the hip and knee with reference to the ankle joint motion, compared to the control group. There was no statistically significant difference in ankle dorsiflexion between groups. Control group reached maximal ankle dorsiflexion at higher point of descent than LBP group.
The findings support the hypothesis that the strategy of movement is different in subjects with and without back pain. They may suggest that subjects with low back pain in maximal squat use the hip joint and knee joint to a greater extent than subjects without back pain, with comparable ankle dorsiflexion. Clinicians should take into consideration the influence of ankle motion and timing on exercise biomechanics in persons suffering from low back pain.
The aim of the article is to compare three programs for the optical text recognition. The problem of the optical text recognition has been defined. Next, briefly the functionality of this technology ...was described. The most important programs realizing the discussed problem were also characterized. The selected programs were tested using two samples of machine writing in Polish. The speed of the text recognition process was determined. The correctness of characters and words recognition in the analyzed text was also specified.
This study examines the efficiency of certain software tasks in applications developed using three frameworks for the Android system: Android SDK, Qt and AppInventor. The results obtained using the ...Android SDK provided the benchmark for comparison with other frameworks. Three test applications were implemented. Each of them had the same functionality. Performance in the following aspects was tested: sorting a list of items using recursion by means of the Quicksort algorithm, access time to a location from a GPS sensor, duration time for reading the entire list of phone contacts, saving large and small files, reading large and small files, image conversion to greyscale, playback time of a music file, including the preparation time. The results of the Android SDK are good. Unexpectedly, it is not the fastest tool, but the time for performing most operations can be considered satisfactory. The Qt framework is overall about 34% faster than the Android SDK. The worst in terms of overall performance is the AppInventor: it is, on average, over 626 times slower than Android SDK.
Frequently the quality of a path returned by a pathfinding algorithm is more important than the performance of that algorithm. This paper presents a new algorithm, based on A*, which is better suited ...for use in 3D game engines. The modification was evaluated by a series of comparative tests. The standard A* algorithm was used as a benchmark in the comparisons. The changes in the algorithm consist in using a different heuristic, adding vertex penalties, and post-processing of the path. A custom-built 3D graphics engine was used as the test environment. The paths generated by the new algorithm are a more natural choice for humans than the ones selected by the standard A* algorithm.
The subject of the article is to compare the methodologies for the production of mobile applications in Swift and Objective-C languages. The similarities and differences of the implementation of ...applications for these two programming languages will be identified as a part of the analysis. An Magic Drawing Board application using Quartz 2D engine was designed and implemented. Two identical functional applications were created. The comparative analysis was carried out only after a thorough explanation of the implemented views.
Celem pracy była analiza i badanie programowej platformy Node.js i frameworka Laravel, a także porównanie wydajności serwisów utworzonych za pomocą tych technologii. Testy wydajności aplikacji ...przeprowadzono za pomocą oprogramowania Apache Benchmark i Apache JMeter. Analiza obejmuje teoretyczne i praktyczne aspekty ich funkcjonowania.
Artykuł przedstawia analizę porównawczą wybranych algorytmów, służących do rozwiązywania Sudoku. Porównywane są puzzle różnej wielkości, posiadające różny poziom trudności. Sprawdzany jest wpływ tych ...czynników na czas działania algorytmów. Na potrzeby badań stworzono specjalną aplikację, która zawiera wszystkie potrzebne algorytmy.
Celem artykułu było tworzenie i analiza aplikacji webowej na bazie frameworku AngularJS. Dla aplikacji zostało napisane API po stronie serwera z połączeniem do bazy danych. Była przeprowadzona ...analiza teoretyczna związana z funkcjonowaniem badanego frameworku. Przeanalizowane wady i zalety podejścia frameworku do tworzenia aplikacji webowych. Były przeprowadzone badania wydajności oraz linii kodu utworzonej aplikacji
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