The notion of the ‘principles of law’ in the light of the idea of ‘essentially contested concepts’

Pomimo istnienia wielu opracowań dotyczących teoretycznych właściwości „zasad prawa” żadna z koncepcji obecnych w polskim porządku prawnym nie została dotąd uznana za dominującą i bezsprzecznie trafniejszą niż pozostałe. Podobna sytuacja panuje w światowej teorii prawa. W niniejszym opracowaniu podjęto próbę zbadania przyczyn tego stanu rzeczy przez zaprezentowanie założeń mało znanej w nauce polskiej idei „pojęć co do istoty kwestionowanych” (essentially contested concepts – ECC), stworzonej przez Waltera B. Galliego i zastosowanie jej do analizy pojęcia zasad prawa. Istnieją dwie główne możliwe interpretacje idei. Zależnie od poglądów przyjętych w tej kwestii, może ona pełnić rolę analitycznego wzorca opisującego typowy zestaw cech charakteryzujących pojęcia wyjątkowo w nauce sporne, w świetle których warto je wraz z otaczającą dyskusją przestudiować. Drugą możliwość stanowi uznanie jej za ontologiczną „hipotezę wyjaśniającą”, zgodnie z którą każdemu ECC z konieczności towarzyszy nierozstrzygalność debaty o właściwy sposób użycia. Niezależnie od zajętego stanowiska, prześwietlenie „zasad prawa” z wykorzystaniem metodologii ECC pozwala pełniej spojrzeć na dotyczącą ich dyskusję z perspektywy „zewnętrznej”. To zaś pozwala sformułować tezę, że argumentacja za konkretnymi koncepcjami zasad powinna w większym stopniu obejmować użyteczność uważanej za słuszną teorii niż konwencjonalne z natury argumenty dotyczące tego, czym zasady w rzeczywistości są.Despite many studies on the theoretical properties of the ‘principles of law’ none of the theories proposed has been recognised as a leading or more accurate one than others. The paper is an attempt to examine the reasons for this, by examining the notion of the ‘principles of law’ in the light of the idea of ‘essentially contested concepts’ (ECC), introduced by Walter B. Gallie. This concept is little known in Polish legal scholarship. Depending on the views regarding its nature, the ‘essentially contested concept’ may be seen as an analytic framework pointing at its attributes and the attributes of a dispute about it, or as an ontological ‘explanatory hypothesis’ attributing to certain concepts a natural impossibility of reaching an agreement as to the proper use of these concepts. Regardless of the adopted view, the analysis of the ‘principles of law’ as an essentially contested concept provides a possibility to cast a glance at the discussion concerning their theoretical nature from an ‘external’, or independent point of view. This in turn allows for a thesis that the argumentation for a specific way of use of the concept of ‘principles’ should, to a greater extent than it is done by statements concerning the true nature of ‘principles’, which are the conventional by nature, advocate the suitability and utility of the theories proposed

Effects of Dreissena polymorpha and Pyganodon grandis on algal density

General EcologyInvasive species often compete with native species for various resources. This study investigated how an invasive species in Douglas Lake, the zebra mussel, and a native species, freshwater clams, would impact algal communities through their feeding habits. We set up aquaria with different treatments of clams and zebra mussels in the boatwell at the University of Michigan Biological Station (UMBS) and monitored algal populations through chlorophyll-a levels. The zebra mussel treatment had the highest chlorophyll-a levels and the zebra mussel and clams treatment had the lowest chlorophyll-a levels on Day 4. The higher levels of chlorophyll-a may be due to the selective feeding of zebra mussels while the lower levels of chlorophyll-a may be due to the non-selective feeding of native clams. Our findings may be useful to understand how zebra mussels are affecting algal populations and how that may in turn affect native clam populations.https://deepblue.lib.umich.edu/bitstream/2027.42/147908/1/Obuchowski_2018.pd

Seismic multiple events – a study on signals’ separation

In this paper we investigate an issue of multiple seismic events. Such events might occur in the case of both natural and mine-induced seismicity. In this paper we investigate an issue whether the distances between two overlapping impulses can be derived from a noisy seismic vibration measurement if the impulses are not equally spaced in time. Such distances might be therefore used for localization of the events or even for detection if more than one event occurred. The methodology is based on minimum entropy deconvolution (MED) and automatic peak finding. Simulated data analysis are performed in order to examine MED with different distances between events. Moreover, comprehensive simulated data analysis provide recommendations regarding MED filter size

Bearings damage detection in presence of heavy non-Gaussian noise via cyclo-stationary analysis

A problem of rolling element bearings diagnostics is discussed in the paper. In the classical approach, time domain detectors (e.g. kurtosis) or frequency domain representation (envelope spectrum analysis) are used to identify a damage in bearings. However, in our case, the machine (copper ore crusher) produces randomly spaced in time heavy impulsive disturbances related to normal operation of the machine. It eliminates completely possibility of detection of damage in time domain or using analysis of the envelope spectrum of the raw vibration signal. It is well known that effectiveness of envelope analysis might be significantly improved if the signal is pre-processed before enveloping. Unfortunately, again, almost all known criteria based on maximization of impulsiveness of signal in time domain fail in this case. In the paper we propose to incorporate cyclostationarity instead of impulsiveness, namely we propose to perform the spectral coherence density analysis

Identification of cyclic components in presence of non-Gaussian noise – application to crusher bearings damage detection

In this paper an issue of local damage detection in a rolling element bearing is discussed. The bearing operates in a hummer crusher, thus the vibration signal acquired on the housing contains a lot of impacts that originate in various sources. In the case of local damage detection it is crucial to find a set of cyclic impulses in the signal. These impulses are informative, in spite of impulses related to the crushing process, which are non-informative. In order to find the damage signature we provide feasibility study on a tool based on cyclostationary approach, namely cyclic spectral coherence. This comprehensive analysis includes study on four different signals from bearings in various condition and operating with or without load applied. This analysis is preceded by motivating preliminary analysis where we examine a few widely-used methods for local damage detection

Time-varying group delay as a basis for clustering and segmentation of seismic signals

In this paper the applications of group delay in seismic vibration signals analysis are discussed. A method which bases on the autoregressive model with sliding-window is used to track volatility of signal’s properties in time. The analysis of time-frequency maps of group delay can be used in a process of distinguishing signals of different characteristics. Moreover, the method is robust for the different parameters of the sliding-window AR model. In the article applications of the time-frequency maps of group delay in a signal segmentation and clustering are also discussed. In seismic analysis an ability to distinguish signals with different seismic nature is very important, especially in case of safety in copper-ore underground mines. Creation of tools for revealing the origin of vibration will have positive impact on evaluation of hazard level

Seismic signal segmentation procedure using time-frequency decomposition and statistical modelling

In the paper a novel automatic seismic signal segmentation procedure is proposed. This procedure is motivated by analysis of real seismic vibration signals acquired in an underground mine. During regular mining activities in the underground mine one can expect some seismic events which appear just after the mining activity, e.g. blasting procedures, provoked relaxation of rock and some events that are unexpected, like natural rock burst. It often happens that, during one signal realization, several shocks (events) appear. Apart from two main sources of events (i.e. rock burst and blasting), other activities in the mine might also initiate seismic signal recording procedure (for example machine moving nearby the sensor). Obviously, significance of each type of recorded signal is very different, its shape in time domain, energy and frequency structure (i.e. spectrum of the signal) are different. In order to recognize these events automatically, recorded observation should be pre-processed in order to isolate a single event. The problem of signal segmentation is investigated in literature, several application domains might be found. Although, there are just a few works on seismic signal segmentation. In this paper we propose to use a time-frequency decomposition of the signal and model each sub-signal at every frequency bin using statistical methods. Narrowband components are much easier to search for so called structural breakpoint, i.e. time instance when properties of signal significantly change. It is obvious that simple energy-based methods applied to raw signal fail when one event begins before the previous one relaxed. In order to find beginning and end of a single event we propose to use measures based on empirical quantiles estimated for each sub-signal and, finally, aggregate 2D array into 1D probability vector which indicates location where statistical features has switched from one regime to another one. The proposed procedure can be applied in order to improve time domain isolation of single event for the case, when duration of signal acquisition is longer than duration of the event or to isolate single event from sequence of events (recorded for example during blasting)

Combination of ICA and time-frequency representations of multichannel vibration data for gearbox fault detection

In the paper a multichannel vibration data processing method is presented in the context of local damage detection in gearboxes. The purpose of the approach is to obtain more reliable information about local damage when using several channels in comparison to results obtained for single channel vibration. The method is a combination of time-frequency representation and Independent Component Analysis (ICA) but applied not to raw time series but to each slice (along to time) from spectrogram. Finally we create new time-frequency map, that after aggregation clearly indicates presence of damage. In the paper we will present details of the method and benefits of using our procedure. We will refer to autocorrelation function of mentioned aggregated new time frequency map (1D signal) or simple spectrum (that might be somehow linked to classical envelope analysis). We believe that results are very convincing – detection of cyclic impulses associated to local damage are clearly identifiable. To validate our method we use real vibration data from heavy duty gearbox used in mining industry