Vilnius Gediminas Technical University
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Public spaces: tradition versus the present
No full textThe problems of public spaces in contemporary urban context as well as their historical roots are being
examined. The author claims that the legacy of the past was pushed aside as well as theoretical alternatives
that could change the urban planning and urban design paradigms of the last century. As soon as concept
of Camillo Sitte (as alternative to visions of Le Corbusier) was ignored, the functions and role of urban
public spaces has been interpreted in a simplified way. Pioneering research done by Christopher Alexander
and revised by his close associate Nikos Salingaros focuses on the “pattern language“ and can be useful
intellectual tool in rethinking and reconsidering the shape and role of public spaces in larger Lithuanian
cities. Some contemporary examples of the formation of urban spaces taken from different locations of the
world are discussed in the context of insights of Christopher Alexander and Nikos Salingaros
Soft asphalt and double Otta Seal—self-healing sustainable techniques for low-volume gravel road rehabilitation
No full textIncreased traffic flow on low-volume gravel roads and deficiencies of national road
infrastructure, are increasingly apparent in Lithuania. Gravel roads do not comply with requirements,
resulting in low driving comfort, longer travelling time, faster vehicle amortization, and dustiness.
The control of dustiness is one of the most important road maintenance activities on gravel roads.
Another important issue is the assurance of required driving comfort and safety. Soft asphalt and
Otta Seal technologies were proposed as a sustainable solution for the improvement of low-volume
roads in Lithuania. Five gravel roads were constructed with soft asphalt, and 13 gravel roads were
sealed with double Otta Seal, in 2012. The main aim of this research was to check soft asphalt and
double Otta Seal’s ability to self-heal, on the basis of the results of the qualitative visual assessment
of pavement defects and distress. The qualitative visual assessment was carried out twice a year
following the opening of the rehabilitated road sections. The results confirmed soft asphalt and
double Otta Seal’s ability to self-heal. The healing effect was more than 13% and 19% on roads with
soft asphalt and double Otta Seal, respectively. In addition, on some roads, all cracks observed in
spring self-healed during summer
The research and application of the stroke affected human upper extremity dynamical model
Get PDFDisertacijoje nagrinėjamos žmonių reabilitacijos metu kylančios problemos, taikant klinikinius funkcinių judesių vertinimo metodus, kuriuose galima subjektyvioji dedamoji. Sukurti algoritmai, skirti viršutinės galūnės judesių kokybei nu-statyti reabilitacijos metu. Tyrimų objektas yra žmogaus viršutinė galūnė (VG), kurios judesio motorika yra sutrikusi dėl insulto pažeidimų. Atlikta VG judesių kintamumo ir VG judesių kokybės kiekybinio įvertinimo analizė. Atliktų VG judesių kiekybinis vertinimas svarbus optimaliai reabilitacijos programai parinkti, reabilitacijos eigai sekti ir judesių kokybei nustatyti.
Pagrindiniai disertacijos uždaviniai yra šie: nustatyti žmogaus viršutinės galūnės judesių kokybės vertinimo kiekybinius rodiklius, sukurti metodiką, skirtą insultą patyrusių žmonių su labai sutrikusia viršutinės galūnės funkcija, judesiams tirti, sukurti universalius žmogaus viršutinės galūnės kinematinį ir dinaminį skaitinius modelius, ištirti VG motorikos kintamumo įtaką judesių kokybei vertinti. Insultą patyrę žmonės atliko klinikinių VG motorinių funkcinių testų judesius, o kinematiniai parametrai išmatuoti kamerų sistema arba inerciniais jutikliais.
Įvadiniame skyriuje aptariama tiriamoji problema, darbo aktualumas, aprašomas tyrimų objektas, tyrimų metodika, darbo mokslinis naujumas ir darbo rezultatų praktinė reikšmė, formuluojami uždaviniai, darbo tikslas, ginamieji teiginiai.
Pirmasis skyrius skirtas literatūros analizei. Jame pagrįsta temos svarba, vir-šutinės galūnės reabilitacijai taikomi klinikiniai metodai, pateikti skaitiniams tyrimams naudojami judesių matavimo įrankiai, esami modeliai ir jų trūkumai. Skyriaus pabaigoje formuluojamos išvados ir tikslinami disertacijos uždaviniai.
Antrajame skyriuje aprašyti sveikųjų tiriamųjų ir žmonių, patyrusių insultą judesių tyrimai. Sudaryti trys žmogaus rankos modeliai, naudojami skaitinių tyrimų metu gautiems duomenims apdoroti.
Trečiajame skyriuje pateikti rezultatai. Nustatyta, kad insultą patyrusių žmonių viršutinės galūnės judesių kokybė gali būti vertinama skaičiuojant me-chaninį darbą ir galią judesio metu. Insultą patyrę žmonės reabilitacijos metu pagerino VG judesių kokybę nuo 2 iki 50 kartų.
Disertacijos tema paskelbti 7 straipsniai: keturi – duomenų bazės Clarivate Analytics Web of Science leidiniuose, turinčiuose citavimo rodiklį, du – kitų tarptautinių duomenų bazių leidiniuose, vienas – konferencijų pranešimų rinkinyje. Disertacijos tema perskaityta 10 pranešimų Lietuvos ir kitų šalių konferencijose
Energy efficiency in the long run in the selected European countries
No full textn the presented paper assumption is being raised that ceteris paribus forecasted energy efficiency until the year 2050 reveals competitive potential, which could be reached if technological progress is ongoing and no radical changes in the energy consumption culture are observed. The research methodology is as follows. In order to clarify what trends of energy efficiency change are preconditioned by the structure of the economy, technological potential and behavioral patterns, activity level and energy intensity in the household sector are forecasted for the selected European countries – Poland, Lithuania and Germany. Lithuania and Poland represent here the countries slightly less economically developed as compared to highly developed Germany. Long-range energy forecasting software LEAP, developed by Stockholm Environment Institute is being employed for the long-term forecasting of energy use and energy intensities in the household sectors. The obtained results, as we have expected, allow verifying if consistent patterns of energy intensity change is existent for currently comparatively less developed and better countries, and if such patterns differ. Peculiarities of energy intensity change in less developed and more developed European countries are to be economically interpreted. The obtained results will allow to judge about change of competitiveness of the considered countries. Provided insights can be instrumental for devising national economic policies oriented on more efficient energy use in the long run
A Decision Framework under a Linguistic Hesitant Fuzzy Set for Solving Multi-Criteria Group Decision Making Problems
No full textWith fast-growing interest in sustainable healthcare management, proper selection and evaluation of hospitals become highly essential. Generally, experts/decision-makers (DMs) prefer qualitative information for rating objects. Motivated by this idea, in this paper, a linguistic hesitant fuzzy set (LHFS) is adopted for elicitation of preference information. The LHFS provides qualitative preferences of DMs as well as reflects their hesitancy, inconsistency, and vagueness. Motivated by the power of LHFS, in this paper we present a new decision framework that initially presents some operational laws and properties. Further, a new aggregation operator called simple linguistic hesitant fuzzy weighted geometry (SLHFWG) is proposed under the LHFS context that uses the strength of power operators. Some properties of SLHFWG are also investigated. Criteria weights are estimated using a newly proposed linguistic hesitant fuzzy statistical variance (LHFSV) method, and objects are ranked using the newly proposed linguistic hesitant fuzzy VIKOR (visekriterijumska optimizacijai kompromisno resenje) (LHFVIKOR) method, which is an extension of VIKOR under the LHFS context. The practicality and usefulness of the proposal are demonstrated by using a hospital evaluation example for sustainable healthcare management. Finally, the strengths and weaknesses of the proposal are realized by comparison with other methods.This article belongs to the Special Issue Multi-Objective and Multi-Attribute Optimisation for Sustainable Development Decision AidingThe authors thank the editor and the anonymous reviewer(s) for their insights that helped improve the quality of the research. The authors also thank the funding agencies University Grants Commission (grant no. F./2015-17/RGNF-2015-17-TAM-83) and Department of Science and Technology, Ministry of Science and Technology (grant no. SR/FST/ETI-349/2013) for their financial aid
Compressive Strength and Durability Properties of Structural Lightweight Concrete with Fine Expanded Glass and/or Clay Aggregates
No full textThis study is focused on the experimental investigation of compressive strength and durability properties of lightweight concrete mixtures with fine expanded glass and expanded clay aggregates using different microfillers. The paper proposes the relationships between the compressive strength and density of concrete mixtures with different proportions of the lightweight aggregates mentioned above. The performed experimental studies have revealed the tendencies of possible usage of different amounts of fine lightweight aggregates and their combinations in the production of concrete mixtures depending on the demands of practical application. Following the requirements for structural concrete subjected to environmental effects, durability properties (alkaline corrosion and freeze–thaw resistance) of the selected concrete mixtures with expanded glass aggregate were studied. The results of the experimental investigations have shown that durability of tested concrete specimens was sufficient. The study has concluded that the mixtures under consideration can be applied for the production of structural elements to which durability requirements are significant.This research is/was funded by the European Social Fund according to the activity ‘Improvement of researchers’ qualification by implementing world-class R&D projects’ of Measure No. 09.3.3-LMT-K-712 (Project No. 09.3.3-LMT-K-712-01-0145)
Investigation of the Behavior of Hardening Masonry Exposed to Variable Stresses
No full textThis paper analyzes the behavior of masonry under variable loads during execution (construction stage). It specifies the creep coefficient for calcium silicate brick masonry, presenting the research data of masonry deformation under variable and constant long-term loads. The interaction of separate layers of composite material in masonry is introduced and the formulae for determining long-term deformations are offered. The research results of masonry’s compressive strength and deformation properties under variable and constant long-term loads are presented. These are then compared to calculated ones. According to the presented comparison, the calculated long-term deformations coincide quite well with those determined experimentally.This article belongs to the Section Structure Analysis and Characterizatio
Investigation of Hyperbolic Metamaterials
No full textComposites designed by employing metal/dielectric composites coupled to the components of the incident electromagnetic (EM) fields are named metamaterials (MMs), and they display features not observed in nature. This type of artificial media has attracted great interest, resulting in groundbreaking theory that bridges the gap between EM and photonic phenomena. Practical applications of MMs have been delayed due to the high losses related to the use of metallic composites, on top of the challenges in manufacturing nanoscale, three-dimensional structures. Novel materials—for instance, graphene or transparent-conducting oxides (TCOs), employed for the production of multilayered MMs—can significantly suppress undesirable losses. It is worthwhile noting that three-layered nanocomposites enable an increase in the frequency range of the surface wave. This work analyzes recent progress in the physics of multilayered MMs. We deliver an outline of key notions, such as effective medium approximation, and present multilayered MMs based on the three-layered structure. An overview of graphene multilayered MMs reveals their ability to support Ferrell–Berreman (FB) modes. We also describe the tunable properties of the multilayered MMs.This article belongs to the Special Issue Photonic Metamaterial
The effect of multi-walled carbon nanotubes on the rheological properties and hydration process of cement pastes
No full textThe properties of cementitious materials can be noticeably improved by the addition of carbon nanotubes (CNTs). It is important to detect the effects of the pellets containing multi-walled CNTs, dispersed in carboxyl-methyl cellulose, on the hydration process of fresh cement pastes, and physical or mechanical properties of hardened cement paste specimens, obtained without the use of commercially available surfactants and plasticisers, in order to use CNTs in cementitious materials more effectively. The influence of dispersed CNTs in different amounts (from 0 to 0.5%) on the pH and electrical conductivity values of water solutions and fresh cement pastes, as well as on the rheological properties, setting time and exothermic reaction of fresh cement pastes or on the physical and mechanical properties of hardened cement paste specimens was analysed in this work. It can be stated, that 0.005% is the marginal amount of CNTs, as amounts above 0.005% deteriorate the hydration parameters of cement pastes. This was confirmed by decreased values in electrical conductivity (approximately 17%), pH (approximately 6.8%) and dynamic viscosity (approximately 3 times) tests. Lower pH values lead to a significant retardation of the dissolution of cement minerals and this process is reflected in the setting time (prolonged by 110–130%) and maximum time (extended by 148%) or temperature (decreased by 18.4%) of exothermic reaction. Consequently, the mechanical properties of hardened cement paste specimens (after 28 days) decreased about 10%, as well as water absorption increased up to 10.6%
Prediction of composite indicators using locally weighted quantile regression
Get PDFThe main goal of this paper is to improve the existing methods and tools used for
solving penalized quantile regression problems. We modified the quantile regression method by
implementing the extreme learning machine (ELM) algorithm and features of locally weighted
regression. Also, we used different penalty functions. A modified method was used for the onestep-
ahead prediction of the composite indicator (CI) of the Lithuanian economy. Our analysis
showed that the prediction error of the modified locally weighted quantile regression is smaller in
comparison to the other quantile regression