Generalized stepwise transmission irregular graphs

The transmission ${\rm Tr}_G(u)$ of a vertex $u$ of a connected graph $G$ is the sum of distances from $u$ to all other vertices. $G$ is a stepwise transmission irregular (STI) graph if $|{\rm Tr}_G(u) - {\rm Tr}_G(v)|= 1$ holds for any edge $uv\in E(G)$. In this paper, generalized STI graphs are introduced as the graphs $G$ such that for some $k\ge 1$ we have $|{\rm Tr}_G(u) - {\rm Tr}_G(v)|= k$ for any edge $uv$ of $G$. It is proved that generalized STI graphs are bipartite and that as soon as the minimum degree is at least $2$, they are 2-edge connected. Among the trees, the only generalized STI graphs are stars. The diameter of STI graphs is bounded and extremal cases discussed. The Cartesian product operation is used to obtain highly connected generalized STI graphs. Several families of generalized STI graphs are constructed

New transmission irregular chemical graphs

The transmission of a vertex $v$ of a (chemical) graph $G$ is the sum of distances from $v$ to other vertices in $G$. If any two vertices of $G$ have different transmissions, then $G$ is a transmission irregular graph. It is shown that for any odd number $n\geq 7$ there exists a transmission irregular chemical tree of order $n$. A construction is provided which generates new transmission irregular (chemical) trees. Two additional families of chemical graphs are characterized by property of transmission irregularity and two sufficient condition provided which guarantee that the transmission irregularity is preserved upon adding a new edge

Geodetic and seismological observations applied for investigation of subsidence formation in the CSM Mine (Czech Republic)

Purpose. Undermined areas are affected by the creation of subsidence depressions due to long-term underground mining. In general, different geodetic methods are applied to obtain further information needed to determine the spatial development of the formation of a subsidence depression. Methods. Application of these surveying methods enables us to investigate spatio-temporal changes of landscape relief in detail. Although the development of surveying technologies is in progress at present, conventional geodetic methods are still in use. Nowadays Global Navigation Satellite System (GNSS) surveying is mostly used for obtaining the actual degree of relief affection in undermined areas. Considering that during coal extraction induced seismic events are observed underground and on the surface, some seismological methods for their parameters determination were applied, e.g. foci location of induced seismic events, their classification by units of magnitude and by released seismic energy, frequency energy distribution, construction of Benioff graph and its derivation for assessment of adjacent working endangerment. Findings. The results of the assessment and analyses of spatial data demonstrate the real development of the sub-sidence depression under study and the relief changes of the landscape during the investigated period, respectively. Originality. It was recognized that all methods applied in this study represent very helpful tools for surveying subsidence depression and simultaneous monitoring of seismic activity development on an undermined area. Practical implications. Based on obtained results it is possible to perform a comparison of current subsidence dimensions with the original rate of affection.Мета. Дослідження причин утворення просідань земної поверхні в околиці шахти CSM (Чеська Республіка) за допомогою геодезичних і сейсмологічних методів спостереження. Методика. В роботі використано сейсмічні методи для визначення локалізації місць явищ техногенної сейсмічності, їх класифікації за магнітудами і кількістю виділеної сейсмічної енергії та її частотного розподілу; побудову графіка Беньофа та його модифікацію для оцінки безпеки суміжних до шахти територій; моделювання просторово-часового розвитку опускання поверхні за допомогою GPS-вимірювань. Результати. У результаті оцінки та аналізу просторових даних була визначена реальна область просідань і зміни навколишнього рельєфу протягом всього часу проведення досліджень. Ґрунтуючись на аналізі наявних сейсмічних даних та наземних GPS-вимірювань, встановлено, що протягом досліджуваного періоду ніякого виразного впливу розвитку зсувів і деформацій поверхні через сейсмічну активність не спостерігалося. Виконано моделювання просторово-часового розвитку опускання поверхні у досліджуваній області, що дозволило визначити швидкість осідання поверхні з часом. Визначено горизонтальні переміщення окремих точок і встановлено, що великі тектонічні розломи створюють природний бар’єр зсувам у масиві. Наукова новизна. Використання унікального комплексу методів дослідження та моніторингу, застосовані у даній роботі, дозволили точно виявити область просідання поверхні й причини її утворення, а також здійснити моніторинг сейсмічної активності в районі, порушеному гірничими роботами. Практична значимість. Отримані результати дозволяють порівняти сучасний стан утворених просідань з їх початковими параметрами, а також прогнозувати інтенсивність їх розвитку у часі.Цель. Исследование причин образования проседания земной поверхности в окрестности шахты CSM (Чешская Республика) при помощи геодезических и сейсмологических методов наблюдения. Методика. В работе использовано сейсмические методы для определения локализации очагов явлений техногенной сейсмичности, их классификации по магнитудам и количеству выделенной сейсмической энергии и ее частотного распределения; построение графика Беньофа и его модификацию для оценки безопасности прилегающих к шахте территорий; моделирование пространственно-временного развития опускания поверхности при помощи GPS-измерений. Результаты. В результате оценки и анализа пространственных данных была определена реальная область проседаний и изменения окружающего рельефа в течение всего времени проведения исследований. Основываясь на анализе имеющихся сейсмических данных и наземных GPS-измерений, установлено, что в течение исследуемого периода никакого выразительного влияния развития смещений и деформаций поверхности из-за сейсмической активности не наблюдалось. Выполнено моделирование пространственно-временного развития опускания поверхности в исследуемой области, позволившее определить скорость оседания поверхности с течением времени. Определены горизонтальные перемещения отдельных точек и установлено, что крупные тектонические разломы создают естественный барьер смещениям в массиве. Научная новизна. Использование уникального комплекса методов исследования и мониторинга, примененные в данной работе, позволили точно выявить область проседания поверхности и причины ее образования, а также осуществить мониторинг сейсмической активности в районе, затронутом горными работами. Практическая значимость. Полученные результаты позволяют сравнить современное состояние образовавшейся впадины с ее первоначальными параметрами, а также прогнозировать интенсивность ее развития со временем.This article was written in connection with the Project Institute of Clean Technologies for Mining and Utilization of Raw Materials for Energy Use – Sustainability Program (reg. No.CZ.1.05/2.1.00/03.0082 and MSMT LO1406), which is supported by the Research and Development for Innovations Operational Programme financed by the Structural Funds of the European Union and the Czech Republic project for the longterm conceptual development of research organisations (RVO: 68145535). Many thanks to Dr. Karel Holub, emeritus researcher from the Institute of Geonics of the Czech Academy of Sciences, for his helpful comments and advices during preparation of manuscript. R.I.P

Mobile radio alternative systems study. Volume 1: Traffic model

The markets for mobile radio services in non-urban areas of the United States are examined for the years 1985-2000. Three market categories are identified. New Services are defined as those for which there are different expressed ideas but which are not now met by any application of available technology. The complete fulfillment of the needs requires nationwide radio access to vehicles without knowledge of vehicle location, wideband data transmission from remote sites, one- and two way exchange of short data and control messages between vehicles and dispatch or control centers, and automatic vehicle location (surveillance). The commercial and public services market of interest to the study is drawn from existing users of mobile radio in non-urban areas who are dissatisfied with the geographical range or coverage of their systems. The mobile radio telephone market comprises potential users who require access to the public switched telephone network in areas that are not likely to be served by the traditional growth patterns of terrestrial mobile telephone services. Conservative, likely, and optimistic estimates of the markets are presented in terms of numbers of vehicles that will be served and the radio traffic they will generate

Microgel-based surface modifying system for stimuli-responsive functional finishing of cotton

An innovative strategy for functional finishing of textile materials is based on the incorporation of a thin layer of surface modifying systems (SMS) in the form of stimuli-sensitive microgels or hydrogels. Since the copolymerization of poly(N-isopropylacrylamide) with an ionizable polymer, such as chitosan, results in a microgel that is responsive to both temperature and pH, the microparticulate hydrogel of poly-NiPAAmchitosan copolymer (PNCS) was synthesized using surfactant-free emulsion method. The microparticle size in dry (collapsed) state is estimated at 200nm by SEM and TEM, and effect of temperature and pH on microparticles was investigated by DLS and UV–vis spectrophotometry. The incorporation of PNCS microparticles to cotton material was done by a simple pad-dry-cure procedure from aqueous microparticle dispersion that contained 1,2,3,4-butanetetracarboxylic acid (BTCA) as a crosslinking agent. This application method provided sufficient integrity to coating by maintaining the responsiveness of surface modifying system. The stimuli-responsiveness of modified cotton fabric has been confirmed in terms of regulating its water uptake in dependence of pH and temperature

Characterization of Reverberation Chambers for OTA Measurements of Wireless Devices: Physical Formulations of Channel Matrix and New Uncertainty Formula

The paper deals with reverberation chambers for over-the-air (OTA) testing of wireless devices for use in multipath. We present a formulation of the S-parameters of a reverberation chamber in terms of the free space S-parameters of the antennas, and the channel matrix in the way this is known from propagation literature. Thereby the physical relations between the chamber and real-life multipath environments are more easily explained. Thereafter we use the formulation to determine the uncertainty by which efficiency-related quantities can be measured in reverberation chamber. The final expression shows that the uncertainty is predominantly determined by the Rician K-factor in the reverberation chamber rather than by the number of excited modes, assumed by previous literature. We introduce an average Rician K-factor that is conveniently expressed in terms of the direct coupling between the transmitting and receiving antennas (corresponding to a line-of-sight contribution) and Hill's transmission formula (corresponding to a multipath or non-line-of-sight contribution). The uncertainty is expressed in terms of this average K-factor and geometrical mode stirring parameters, showing strong reduction by platform and polarization stirring. Finally the formulations are verified by measurements, and the new understanding of uncertainty is used to upgrade an existing reverberation chamber to better uncertainty

Food-web structure in relation to environmental gradients and predator-prey ratios in tank-bromeliad ecosystems

Little is known of how linkage patterns between species change along environmental gradients. The small, spatially discrete food webs inhabiting tank-bromeliads provide an excellent opportunity to analyse patterns of community diversity and food-web topology (connectance, linkage density, nestedness) in relation to key environmental variables (habitat size, detrital resource, incident radiation) and predators: prey ratios. We sampled 365 bromeliads in a wide range of understorey environments in French Guiana and used gut contents of invertebrates to draw the corresponding 365 connectance webs. At the bromeliad scale, habitat size (water volume) determined the number of species that constitute food-web nodes, the proportion of predators, and food-web topology. The number of species as well as the proportion of predators within bromeliads declined from open to forested habitats, where the volume of water collected by bromeliads was generally lower because of rainfall interception by the canopy. A core group of microorganisms and generalist detritivores remained relatively constant across environments. This suggests that (i) a highly-connected core ensures food-web stability and key ecosystem functions across environments, and (ii) larger deviations in food-web structures can be expected following disturbance if detritivores share traits that determine responses to environmental changes. While linkage density and nestedness were lower in bromeliads in the forest than in open areas, experiments are needed to confirm a trend for lower food-web stability in the understorey of primary forests