Use of nearest neighbors (k–nn) algorithm in tool condition identification in the case of drilling in melamine faced particleboard

The purpose of this study was to develop an automatic indirect (non-invasive) system to identify the condition of drill bits on the basis of the measurement of feed force, cutting torque, jig vibrations, acoustic emission and noise which were all generated during machining. The k-nearest neighbors algorithm classifier (k-NN) was used. All data analyses were carried out in MATLAB (MathWorks – USA) environment. It was assumed that the most simple (but sufficiently effective in practice) tool condition identification system should be able to recognize (in an automatic way) 3 different states of the tool, which were conventionally defined as “Green” (tool can still be used), “Red” (tool change is necessary) and “Yellow” (intermediate, warning state). The overall accuracy of classification was 76 % what can be considered a satisfactory result at this stage of studies

Mobile IoT Systems in the Urban Area

An important element of Internet of Things systems (IoT) is wireless data transmission. Narrowband Internet of Things (NB-IoT) and LTE Cat M1 (LTE-M) are the new standards for such transmission intended for LTE cellular networks. Cellular network operators has recently launched such transmission. The article presents the results of measurements of NB-IoT transmission parameters in this network, inside the building and in open urban areas. The main features of the NB-IoT system and measuring equipment are briefly discussed

Ecological risk assessment of chemical contaminants in stormwater sediments

Contaminants bound to suspended solids transported by stormwater pose quantity and quality problems to the water ecosystem. Therefore, it is necessary to carry out an ecological risk assessment. Currently, Polish legal regulations do not require that stormwater sediments should be tested for hazardous substances prior to their removal. Ecological evaluation was performed for polycyclic aromatic hydrocarbons (PAHs) and heavy metals in the sediments from three selected stormwater sedimentation tanks located in urban catchment areas of Kielce city. The purpose this study was to analyze sediments for chemical contaminants and to demonstrate the relationship between contaminant levels and physical attributes of the catchment, including land use, drainage area, age of catchment and impervious surface in the watershed. Levels of PAHs and heavy metals (Cd, Cr, Ni, Pb and Zn) in stormwater sediments were then compared with Polish regulations and ecological screening values to determine their potential risk to environment were established. The results of the current study suggest that stormwater sediments are moderately contaminated with PAHs and heavy metals according to domestic regulations. They are, however, highly contaminated according to ecological benchmarks, which are exceeded several times

Catchment management influence on the magnitude of the total solids load conveyed by the stormwater sewer system – a comparative case study

The aim of the investigations was to make a comparative analysis of TSS concentration and variability in TSS loads as well as to analyse first flush phenomena. That issue is related to the characteristics of two urban catchments located in the city of Kielce. The runoff events observed in the period of investigations (years 2009 – 2016) showed a great diversity. The analyses performed for the study revealed substantial differences in the values of TSS concentration and loads in stormwater from the catchments of concern. The highest TSS concentration in the stormwater for the catchment located at the city outskirts was 252 mg.dm-3, whereas for the catchment in the city centre that value was almost 30 – fold higher and amounted to 7432 mg.dm-3. The analysis of the runoff first flush with respect to the mass of total solids in individual rainfall events showed substantial differences in the course of the process depending on the type of catchment management. In the densely built-up area, the initial 25% and 30% of the volume of runoff transported 25-41% and 30-48% of the solids mass, respectively. In the other catchment, with low and sparsely located buildings, the maximum values of TSS mass were considerably higher and amounted to 22-83% and 28-87%

Monte Carlo simulations of the fracture resistance degradation of asphalt concrete subjected to environmental factors

The paper presents the results of laboratory tests of SCB (semi-circular beam) samples of asphalt concrete, subjected to the destructive effect of water and frost as well as the aging processes. The determined values of material parameters show significant dispersions, which makes the design of mixtures difficult. Statistical analysis of the test results supplemented by computer simulations made with the use of the proprietary FEM model was carried out. The main distinguishing feature of the model is the assignment of material parameters of coarse aggregate and bituminous mortar to randomly selected finite elements. The parameters of the mortar are selected by trial and error to match the numerical results to the experimental ones. The stiffness modulus of the bituminous mortar is, therefore, a substitute parameter, taking into account the influence of many factors, including material degradation resulting from the aging and changing environmental conditions, the influence of voids, and contact between the aggregate and the bituminous mortar. The use of the Monte Carlo method allows to reflect the scattering of the results obtained based on laboratory tests. The computational algorithm created in the ABAQUS was limited only to the analysis of the global mechanical bending response of the SCB sample, without mapping the failure process in detail. The combination of the results of laboratory tests usually carried out on a limited number of samples and numerical simulations provide a sufficiently large population of data to carry out a reliable statistical analysis, and to estimate the reliability of the material designed

The statistical impact of experimental result scatter of asphalt mixtures on their numerical modelling

The paper presents selected test results of asphalt mixture conducted in low temperatures. The obtained parameters are highly diverse. It concerns ultimate breaking loads, stiffness parameters related to Young's modulus but also the fracture course. Statistical analysis upon the results makes it possible to relevantly estimate the material-defining parameter values. Such a random approach leads to the mean values of breaking and fracture-triggering loads, dealing with their dispersion too. The estimated parameters allow to form appropriate numerical models of asphalt mixture specimens. This type of analysis supports the laboratory tests. The paper presents the authors' simplified model considering non-uniform material features. The results reflect the scatter of real laboratory test outcomes. In order to do so an algorithm to calibrate the numerical model parameters was created

Laparoscopic dissection of uterine artery and coagulation uteroovarian ligament for the treatment of symptomatic myomas

Abstract Objectives: Our purpose was to evaluate the effects and safety of laparoscopic dissection of the uterine artery and coagulation of the utero-ovarian ligament in treating symptomatic myomas. Material and methods: We studied 40 women, aged 31 to 50, with symptomatic uterine fibroids undergoing laparoscopic dissection of the uterine artery and coagulation of the utero-ovarian ligament. Ultrasound examination of uterus and dominant fibroid were performed. Their volume reduction was measured. Clinical response was evaluated according to questionnaire assessing the level of menstrual bleeding, pain and urgency. Results: There were no complications during operations. Within 6 months after the surgery the mean uterus volume was reduced by 22% and mean volume of dominant fibroid was reduced by 51%. Six months after the surgery menstrual bleeding was reduced in case of 34/38 patients (85%), completed pain relief has been observed in case of 19/25 patients (76%). In case of 11/15 (73%) patients, a regression of urgency has been observed. Conclusions: Laparoscopic dissection of the uterine artery and coagulation of the utero-ovarian ligament is a safe and effective method of treating symptomatic myomas. It is an alternative to hysterectomy, especially for women who wish to preserve their uteru

The Review of New Scientific Developments in Drilling in Wood-Based Panels with Particular Emphasis on the Latest Research Trends in Drill Condition Monitoring

Drilling is still one of the basic cutting processes that are of particular interest to wood science and technology professionals. As a result, considerable (and very diverse thematically) research has been recently carried out on drilling. The article focuses on the new and quite spectacular approach to drill condition monitoring in wood-based panels machining. One of the most innovative elements in the analyzed research trend is the adoption of the new general methodological assumptions that allow one to define the drill condition monitoring problem as a standard three-class classification. The general effectiveness of the tested monitoring systems (accuracy of classification ACC [%]), ranged between 67% and 82%. The critical classification error (CCE [%]) ranged between 0% and 1.6%. These results seem very promising, yet are still not good enough to develop a commercial monitoring system. A more useful form of obtaining diagnostic data and more effective classification strategies (algorithms) are likely to be required

Economic literacy i.e. significance of economic awareness

Celem artykuïu jest przybliżenie zagadnienia świadomości i edukacji ekonomicznej (w tym finansowej). Tekst ma charakter opracowania przeglądowego i koncepcyjnego i zawiera próbę zdefiniowania pojęcia świadomości ekonomicznej. Wskazano w nim powody i korzyści wynikające z upowszechniania edukacji ekonomicznej oraz zarysowano wybrane dylematy związane z koncepcją i pomiarem świadomości ekonomicznej.The aim of this article is to present the subject of economic (including financial) knowledge and literacy. The text is both a literature review and conceptual elaboration and it attempts to define the notion of economic literacy. The article indicates the reasons and benefits of promoting economic education and outlines a selection of the concept and economic literacy measurement related dilemmas