Correlations in financial time series: established versus emerging markets

Long-time correlations in both well-developed and emerging market indexes are studied. The Hurst exponent as well as detrended fluctuations analysis (DFA) are used as technical tools. Some features that seem to be specific for developing markets are discovered and briefly discussed

Numerical analysis of soil-steel bridge

W pracy przedstawiono analizę numeryczną mostu gruntowo-stalowego w zakresie obciążeń statycznych. Do obliczeń wykorzystano program Abaqus oparty na MES. Maksymalne przemieszczenia uzyskano w kluczu powłoki, a największe naprężenia w narożach. Uzyskane wyniki obliczeń zostały porównane z rezultatami badań doświadczalnych i wcześniejszymi obliczeniami wykonanymi w programie Robot Millenium. Kształt przebiegu obliczonych przemieszczeń i naprężeń jest zbliżony do tych uzyskanych z badań, jednakże bezwzględne wartości były przeważnie większe od pomierzonych. Przy zastosowaniu obu programów obliczeniowych, względne różnice przemieszczeń mieściły się w zakresie 15–39%, a naprężeń 17–44%, z korzyścią dla programu Abaqus. Opracowany model obliczeniowy mostu gruntowo-stalowego w programie Abaqus pozwala uzyskiwać rozsądne wartości sił wewnętrznych w konstrukcji powłoki.The paper presents a numerical analysis of the soil-steel bridge in the scope of static loads. The Abaqus program based on the FEM was used to calculations. Maximum displacements were obtained in the shell crown, and the largest stresses in the haunches. Calculation results were compared with the experimental ones and previous calculations obtained from the Robot Millenium program. The shapes of calculated displacements and stresses are similar to those obtained with the experiment, but the absolute values were generally higher than measured ones. Using both calculation programs, the relative reductions of displacement were in the range of 15–39%, and 17–44% for stresses in favour of the Abaqus program. Developed calculation model of the soil-steel bridge in the Abaqus program allows to obtain reasonable values of internal forces in the shell structure

On effectiveness of conditional admission control for IP QoS network services with REM scheme

Future IP QoS (quality of service) networks are aiming at differentiating transfer quality of packets belonging to different flows. For this purpose, a set of network services (NS) with different QoS objectives is defined and implemented in the network. To a NS a certain amount of network resources, i.e. dedicated link capacity with associated buffer size, is allocated. Moreover, the resources dedicated for one NS are not available for other NSs. Traditional approach for admission control algorithm corresponding to given NS takes into account current traffic conditions inside considered NS. This can lead to the situation, due to traffic fluctuations, that temporary overloaded NS cannot use the spare bandwidth from underloaded in this time other NSs. This paper describes a conditional admission control algorithm (C-AC), allowing us to admit new packet flow conditionally in the case where no available capacity inside a given NS. For conditionally accepted flow currently unused capacity, dedicated to other NS, is allocated. This can be done only in the case when QoS requirements for both the conditionally accepted flow and the flows in progress are satisfied. The conditions for effective using of C-AC algorithm are discussed in the paper, like characteristics of NS borrowing and lending capacity and their current traffic load. To show potential benefits of the approach, exemplary numerical results are included, corresponding to hypothetical NSs using REM (rate envelope multiplexing) scheme

New generation drills with rotary tangent bits as the novelsolution for drilling and reaming in Tertiary and Quateriary formations

W artykule przedstawiono świdry (koronki) nowej generacji z wymiennymi obrotowymi nożami stycznymi do wiercenia i rozwiercania otworów w złożach o średniej zwięzłości, a także do wiercenia horyzontalnego i powrotnego. Przedstawiono rozwiązania poglądowe i konstrukcyjne świdrów do wiercenia otworów strzałowych i rozluźniających w górnictwie odkrywkowym i podziemnym o zakresie średnic od phi 105 do 216 mm oraz do wiercenia i rozwiercania otworów hydrologicznych, a także geologiczno-poszukiwawczych o zakresie średnic phi 250--670 mm.In the paper are presented drills (heads) of new generation with replacable rotary tangential bits for drilling and reaming holes in formations of medium cohesiveness usable also for horizontal and return drilling. There are presented illustrative and design solutions of drills for blasting and relaxing holes drilled in open-cast and underground mining of diametres range phi 105--216 mm and for drilling and reaming hydrogeological as well as geological - exploratory holes of diametres between phi 250 mm and phi 670 mm

Investigation of Self-Diffusion of Titanium by Fluctuation Autocorrelation Method

Diffusion of titanium was examined in the field emission microscope using the fluctuation autocorrelation method. A thick titanium layer (about three monolayers) deposited on a tungsten tip was used. A temperature range of 1260-1410 K was found where diffusion can be described in a hydrodynamic approximation. In this temperature range the diffusion coefficient seems to comply with Arrhenius rule for the activation energy of 1.31 eV and D$\text{}_{0}$ = 3×10$\text{}^{-7}$ cm$\text{}^{2}$s

AQUILA network architecture: first trial experiments

The paper presents trial experiments with IP QoS network services (NS) defined and implemented in the AQUILA pilot installation. The AQUILA NSs (premium CBR, premium VBR, premium multimedia and premium mission critical) provide a framework for supporting a variety of applications generating both streaming and elastic traffic. The measurement experiments confirm that AQUILA architecture differentiates the QoS offered to these NSs. The presented numerical results were obtained in the test network installed in the Polish Telecom (Warsaw) consisting of 8 CISCO routers

On Providing Cloud-awareness to Client's DASH Application by Using DASH over HTTP/2

Mobile Cloud Networks group together mobile users and clouds containing content servers. Hence, they are an ideal framework for media content delivery. Streamswitching adaptive video players cope well with some limitations of Mobile Cloud Networks as low bandwidth and bandwidth variability in access network. Nonetheless, other limitations, as cloud congestion, are difficult to be managed by the video players. This paper presents a system for discovering fault situations at the cloud (e.g., cloud congestion) and notifying to the video player, which will take appropriate actions for saving the quality of media transmission. In proposed implementation the video application is DASH-capable and adaptation action may be both stream rate adaptation and content server adaptation. The communication between client and server uses "bidirectional" communication feature of HTTP/2 thanks to the new deployed modules running DASH over HTTP/2 in both client's and server's applications

Identification of mushroom and murine tyrosinase inhibitors from Achillea biebersteinii Afan. Extract

Growing scientific evidence indicates that Achillea biebersteinii is a valuable source of active ingredients with potential cosmetic applications. However, the data on its composition and pharmacological properties are still insufficient. This study aims to optimize the extraction procedure of the plant material, evaluate its phytochemical composition, and compare anti-tyrosinase potential of A. biebersteinii extracts obtained by various methods. In order to identify compounds responsible for the tyrosinase inhibitory activity of A. biebersteinii, the most active anti-tyrosinase extract was fractionated by column chromatography. The fractions were examined for their skin lightening potential by mushroom and murine tyrosinase inhibitory assays and melanin release assay. HPLC-ESI-Q-TOF-MS/MS analysis of the total extract revealed the presence of several phenolic acids, flavonoids, flavonoid glucosides, and carboxylic acid. Among them, fraxetin-8-O-glucoside, quercetin-O-glucopyranose, schaftoside/isoschaftoside, gmelinin B, 1,3-dicaffeoylquinic acid (1,3- DCQA), and ferulic acid were found in the fractions with the highest skin lightening potential. Based on obtained qualitative and quantitative analysis of the fractions, it was assumed that the caffeoylquinic acid derivatives and dicaffeoylquinic acid derivatives are more likely responsible for mushroom tyrosinase inhibitory activity of A. biebersteinii extracts and fractions. Ferulic acid was proposed as the most active murine tyrosinase inhibitor, responsible also for the reduced melanin release from B16F10 murine melanoma cells. © 2021 by the authors. Licensee MDPI, Basel, Switzerland