In this paper, we study the distributed optimization problem using approximate first-order information. We suppose the agent can repeatedly call an inexact first-order oracle of each individual objective function and exchange information with its time-varying neighbors. We revisit the distributed subgradient method in this circumstance and show its suboptimality under square summable but not summable step sizes. We also present several conditions on the inexactness of the local oracles to ensure an exact convergence of the iterative sequences towards the global optimal solution. A numerical example is given to verify the efficiency of our algorithm.
In this paper, the distributed output regulation problem of linear multi-agent systems with parametric-uncertain leaders is considered. The existing distributed output regulation results with exactly known leader systems is not applicable. To solve the leader-following with unknown parameters in the leader dynamics, a distributed control law based on an adaptive internal model is proposed and the convergence can be proved.
This paper addresses the distributed resilient filtering for discrete-time large-scale systems (LSSs) with energy constraints, where their information are collected by sensor networks with a same topology structure. As a typical model of information physics systems, LSSs have an inherent merit of modeling wide area power systems, automation processes and so forth. In this paper, two kinds of channels are employed to implement the information transmission in order to extend the service time of sensor nodes powered by energy-limited batteries. Specifically, the one has the merit of high reliability by sacrificing energy cost and the other reduces the energy cost but could result in packet loss. Furthermore, a communication scheduling matrix is introduced to govern the information transmission in these two kind of channels. In this scenario, a novel distributed filter is designed by fusing the compensated neighboring estimation. Then, two matrix-valued functions are derived to obtain the bounds of the covariance matrices of one-step prediction errors and the filtering errors. In what follows, the desired gain matrices are analytically designed to minimize the provided bounds with the help of the gradient-based approach and the mathematical induction. Furthermore, the effect on filtering performance from packet loss is profoundly discussed and it is claimed that the filtering performance becomes better when the probability of packet loss decreases. Finally, a simulation example on wide area power systems is exploited to check the usefulness of the designed distributed filter.
Distribution of a word across contexts has proved to be a very useful ap- proximation of the word’s meaning. This paper reflects on the recent attempts to enhance distributional (or vector space) semantics of words with meaning composition, in particular with Fregean compositionality. I discuss the nature and performance of distributional semantic representations and argue against the thesis that semantics is in some sense identical with distribution (which seems to be a strong assumption of the compositional efforts). I propose instead that distribution is merely a reflection of semantics, and a substantially imperfect one. That raises some doubts regarding the very idea of obtaining semantic representations for larger wholes (phrases, sentences) by combining the distributional representations of particular items. In any case, I reject the generally unquestioned assumption that formal semantics provides a good theory of semantic composition, which it would be desirable to combine with distributional semantics (as a theory that is highly successful on the lexical field). I suggest that a positive alternative to the strong reading of the distributional hypothesis can be seen in the philosophy of inferentialism with respect to language meaning. I argue that the spirit of inferentialism is reasonably compatible with the current practice of distributional semantics, and I discuss the motivations for as well as the obstacles in the way of implementing the philosophical position in a computational framework., Ukázalo se, že rozložení slova napříč kontextem je velmi užitečným přiblížením významu slova. Příspěvek se zabývá nedávnými snahami o rozšíření sémantiky slov s významovou skladbou, zejména pak o fregovskou kompozici. Diskutuji o povaze a výkonu distribučních sémantických reprezentací a argumentuji proti té tezi, že sémantika je v určitém smyslu identická s distribucí (což se zdá být silným předpokladem kompozičního úsilí). Místo toho navrhuji, aby distribuce byla pouze odrazem sémantiky a podstatně nedokonalým. To vyvolává určité pochybnosti o samotné myšlence získat sémantické reprezentace pro větší celky (fráze, věty) kombinací distribučních reprezentací jednotlivých položek. V každém případě, Odmítám obecně nezpochybnitelný předpoklad, že formální sémantika poskytuje dobrou teorii sémantické kompozice, kterou by bylo žádoucí kombinovat s distribuční sémantikou (jako teorie, která je na lexikálním poli velmi úspěšná). Navrhuji, že pozitivní alternativu k silnému čtení distribuční hypotézy lze vidět ve filozofii inferenciality s ohledem na jazykový význam. Tvrdím, že duch inferenciality je přiměřeně slučitelný se současnou praxí distribuční sémantiky a diskutuji o motivacích i překážkách ve způsobu implementace filosofické pozice do výpočetního rámce. které by bylo žádoucí kombinovat s distribuční sémantikou (jako teorie, která je na lexikálním poli velmi úspěšná). Navrhuji, že pozitivní alternativu k silnému čtení distribuční hypotézy lze vidět ve filozofii inferenciality s ohledem na jazykový význam. Tvrdím, že duch inferenciality je přiměřeně slučitelný se současnou praxí distribuční sémantiky a diskutuji o motivacích i překážkách ve způsobu implementace filosofické pozice do výpočetního rámce. které by bylo žádoucí kombinovat s distribuční sémantikou (jako teorie, která je na lexikálním poli velmi úspěšná). Navrhuji, že pozitivní alternativu k silnému čtení distribuční hypotézy lze vidět ve filozofii inferenciality s ohledem na jazykový význam. Tvrdím, že duch inferenciality je přiměřeně slučitelný se současnou praxí distribuční sémantiky a diskutuji o motivacích i překážkách ve způsobu implementace filosofické pozice do výpočetního rámce., and Radek Ocelák
The ubiquitin-proteasome pathway fulfills major biological functions, but its physiologic tissue distribution and the interrelationship between pathway component activities and ubiquitin pools are unknown. Therefore, we analyzed free and conjugated ubiquitin, ubiquitin-protein ligation rates (UbPL) and chymotryptic- and tryptic-like proteasome peptidase activities in porcine skeletal muscle, heart, lung, liver, spleen and kidney (n=5 each). There were considerable differences between tissues (p<0.05 for all parameters). Lung and spleen showed high levels of free and conjugated ubiquitin and high UbPL. Proteasome activities were highest in kidney and heart. There were linear relationships between tryptic-like and chymotryptic-like proteasome peptidase activities (r2 = 0.624, p<0.001) and between free and conjugated ubiquitin tissue levels (r2 = 0.623, p<0.001). Tissue levels of free and conjugated ubiquitin correlated linear with UbPL (p<0.005), but they were not correlated with proteasome peptidase activities. The results suggest that tissue ubiquitin pools are tightly regulated and indicate a constant proportion of conjugated ubiquitin. They further support the hypothesis that ubiquitin-protein ligase systems, and probably deubiquitylating enzymes, are key regulators of ubiquitin homeostasis. The detected differences are suggestive of tissue-specific roles of ubiquitin-proteasome pathway components. Besides the known importance of the ubiquitin proteasome pathway in heart, kidney and the immune system, the results suggest the lung as another organ in which ubiquitin proteasome pathway components may also significantly contribute to disease processes., M. B. Patel, M. Majetschak., and Obsahuje bibliografii a bibliografické odkazy
Laboratory studies were conducted to characterise the sorption-desorption behavior of four human pharmaceuticals (carbamazepine, diclofenac, gemfibrozil, and ibuprofen) at three initial concentrations in aqueous solution on one river sediment. The results of the experiments showed that distribution coefficients were either relatively low for diclofenac and ibuprofen or higher for gemfibrozil and carbamazepine. Distribution coefficients (mean Kd values for three initial concentrations), as measured by the batch experiments, were 4.21 ± 0.58 for diclofenac, 4.98 ± 0.29 for ibuprofen, 11.28 ± 1.22 for gemfibrozil, and 44.82 ± 14.89 for carbamazepine. Based on sorption data, migration potential of the pharmaceuticals in surface waters would decrease as follows: diclofenac > ibuprofen > gemfibrozil >> carbamazepine. Only 2.44 ± 1.05%, 3.67 ± 0.35% and 1.79 ± 1.17% of the initially sorbed ibuprofen, gemfibrozil and carbamazepine were desorbed during desorption period of 48 h, respectively. Diclofenac exhibited the highest desorption (15.01 ± 2.59%). Generally, the results indicate that significant amounts of the pharmaceuticals may be eliminated from surface waters via sorption by sediment and that observed low desorption would further limit their migration in surface waters. and Hlavným cieľom štúdie bol výskum sorpcie a desorpcie štyroch humánnych farmaceutík (karbamazepín, diklofenak, gemfibrozil a ibuprofén) pri troch počiatočných koncentráciách vo vodnom roztoku vo vzorke riečneho sedimentu. Výsledky experimentov ukázali, že rozdeľovacie koeficienty boli buď nižšie pre diklofenak a ibuprofén alebo zvýšené v prípade gemfibrozilu a karbamazepínu. Stanovené hodnoty rozdeľovacích koeficientov (priemerné hodnoty Kd pre všetky tri počiatočné koncentrácie) boli 4,21 ± 0,58 pre diklofenak, 4,98 ± 0,29 pre ibuprofén, 11,28 ± 1,22 pre gemfibrozil a 44,82 ± 14,89 pre karbamazepín. Podľa stanovených hodnôt Kd sa bude mobilita skúmaných farmaceutík v povrchových vodách znižovať v poradí: diklofenak > ibuprofén > gemfibrozil >> karbamazepín. Vodou desorbovateľné podiely farmaceutík zo sedimentu boli nízke, pričom len 2,44 ± 1,05%, 3,67 ± 0,35% a 1,79 ± 1,17% z celkového sorbovaného množstva ibuprofénu, gemfibrozilu a karbamazepínu v sedimente sa počas desorpčného experimentu uvoľnilo späť do vody. Diklofenak vykazoval najvyšší rozsah desorpcie zo sedimentu (15,01 ± 2,59%). Všeobecne tieto výsledky naznačujú, že značné množstvá sledovaných farmaceutík môžu byť odstránené z povrchových vôd prostredníctvom sorpcie v sedimente a že pozorovaný nízky rozsah desorpcie bude ešte viac obmedzovať ich mobilitu v povrchových vodách.
A population of the gill parasite Hatschekia pagellibogneravei (Hesse, 1878) was studied on one of its sparid fish hosts, the blackspot seabream, Pagellus bogaraveo (Brünnich), off the coast of Madeira Island, Portugal, northeast Atlantic. Very high infection levels of this copepod were detected, with no significant seasonal differences. Abundance was negatively correlated with fish size. There were significant differences in the distribution of this copepod among the gill arches of the host, which seem to be best explained by differences in water flow within the gill habitat.
Simple 3D distributions of the interplanetary dust cloud deríved from observations in the visible and distributions suggested by IR investigators are compared. Predictions of visual brightness based on IR models are falrly compatible with observations for large (ε<70°) elongations but not close to the Sun. Some reasons for this behaviour and first steps towards more realistic models are díscussed.
If the Shields number of a flow above an erodible bed is higher than one, then the current exerts so high shear stress at the top of a granular bed that the upper part of the bed is eroded and the top of the non-eroded rest of the bed is flat (no bed forms occur). This flow regime is typical for flows over a stationary bed in pipes but it can occur also in open-channel flows, particularly under flood conditions when both the depth and velocity of the flow are high. The current picks up particles from the eroded part of the bed and transports them within the flow. The total load of transported particles is composed of particles transported either as the contact load or as the suspended load, depending on the dispersive mechanism that keeps the particles inside the flow. Solids distribution (i.e. the shape of the concentration profile) of the transported particles across the flow helps to identify an acting dispersive mechanism and hence a mechanism through which the transported particles contribute to flow friction. The paper analyzes the concentration-profile measurements in a medium-sand-slurry current above an erodible stationary bed in a 150-mm pipe. The experiments revealed interesting effects of high shear stress on the shapes of concentration profiles across the flow above the bed. The analysis suggests that carrier turbulence is a prevailing dispersion mechanism within the upper part of the discharge area above the bed for flow conditions characterized by values of the ratio u*b/vt higher than say 4.5. It seems that the shearing action as an exclusive particle dispersion mechanism is confined to the region not far above the top of the bed. Apparently, the high shear stress at the top of the stationary bed is capable of producing turbulent suspension that transports a considerable amount of medium-sand particles (average delivered volumetric concentrations of transported particles up to 0.26) through the 150-mm pipe. and Při proudění vody nad pohyblivým dnem za podmínek vysokého smykového napětí na povrchu dna (Shieldsovo číslo větší než 1) je horní vrstva dna erodována proudem vody a na povrchu neerodované části dna nevznikají dnové útvary. Takové proudění se vyskytuje například v potrubí dopravujícím směs nad sedlinou na dně potrubí, ale může se vyskytnout i v otevřeném korytě, zvláště za povodňové situace, kdy jsou pro proudění typické velká rychlost a velká hloubka vody. Proud unáší částice z erodované vrstvy dna. Mechanismy, které mohou udržovat částice v proudu, jsou v principu dva: turbulentní suspenze a mezičásticový kontakt. Každý z těchto mechanismů způsobuje jiné rozdělení částic, tj. jiný koncentrační profil, po svislici proudu. Měřením koncentračních profilů by tedy mělo být možné odhadnout, jaký mechanismus převažuje v proudění za určitých sledovaných podmínek. Příspěvek analyzuje koncentrační profily měřené v potrubí průměru 150 mm při proudění vodní směsi střednězrnného písku nad pískovou sedlinou. Analýza výsledků měření ukázala, že turbulence v proudu vody je převažujícím mechanismem podpory částic přinejmenším v horní polovině výšky průtočné části potrubí při podmínkách charakterizovaných hodnotou poměru třecí rychlosti ve dně a usazovací rychlosti unášené částice (u*b/vt) větší než přibližně 4,5. Na rozdíl od dřívějších závěrů v literatuře se zdá, že mezičásticové kolize se jako výhradní mechanismus disperze částic uplatňují jen v poměrně omezené oblasti proudu nad povrchem dna. Vysoké smykové napětí ve dně tak přispívá nejen ke vzniku mezičásticových kolizí, ale i k turbulentní podpoře částic. Turbulentní podpora umožňuje dosažení vysokých hodnot (až do 0,26) dopravní koncentrace částic střednězrnného písku ve směsi proudící potrubím průměru 150 mm.
Observations of photometric and spectroscopic data for open clusters and associations have been intensive during the last few years. Incentives are many:
- each cluster is an object for which the state of evolution and other
characteristics can be studied much better than for individual stars
- the systems of open clusters and associations in our own and other galaxies give information about the recent evolution of the galaxies themselves
- the clusters and associations are sensors of the conditions in interstellar space
Collections of observed data have been made by Alter, Ruprecht, Balazs, Vanysek and White in the comprehehsive Prague-Budapest card catalogues. My own efforts in this direction have resulted in computer readable catalogue of open cluster data, of which the 5th edition appeared recently. In collaboration with K. Janes and C.
Tilley of Boston University, I have now entered weight classes. The purpose of these is to monitor the reliability of conclusions based on cluster data. It seems that physical systems of 10-1000 stars can be divided into three categories;
- associations and unbound open clusters
- bound open clusters in the disk
- old open clusters
Properties such as age, linear diameter and abundances are discussed for these categories on the basis of the data contained in the Lund catalogue. The galactic distribution of young clusters and associations shows the existence of complexes inside the thin disk. The system of old open clusters seems to back up the concept of a thick disk.