Abrupt Start Research Articles

SDRE 기법을 이용한 이륜 밸런싱 로봇의 비선형 최적제어

Two-wheeled balancing mobile robots are currently controlled in terms of linear control methods without considering the nonlinear dynamical characteristics. However, in the high maneuvering situations such as fast turn and abrupt start and stop, such neglected terms become dominant and greatly influence the overall driving performance. This paper addresses the SDRE nonlinear optimal control method to take advantage of the exact nonlinear dynamics of the balancing robot. Simulation results indicate that the SDRE control outperforms LQR in the respect of transient performance and required wheel torques. A design example is suggested for the state matrix that provides design flexibility in the SDRE control. It is shown that a well-planned state matrix by reflecting the physics of a balancing robot greatly contributes to the driving performance and stability.

Phonetic realization of glottal stop in Shugni.

Shugni is an underdocumented Indo‐European language, mainly spoken in the Pamir mountains. Orthographically, Shugni used the apostrophe to symbolize the glottal stop phoneme, and the symbol only occurred word initially. In this paper, phonetic manifestation of glottal stop was examined, and the adjacent vowel [a] was compared under five conditions: (1) word‐initial glottal stop followed by [a] and a consonant #[ʔaC1], (2) word‐medial [C2aC1] sequence where [a] was also syllable‐medial, (3) word‐medial [C2aC1] sequence where [a] was syllable‐final, (4) word‐final [a] preceded by a consonant [C2a]#, and (5) a sequence of [C2a]# [ʔaC1] where glottal stop was word‐initial and intervocalic. Four acoustic parameters were measured, and glottal stop was defined as (1) an absence of formant transitions entering or leaving [a], (2) an abrupt start or end of [a]’s magnitude, (3) identifiable stop closure, and (4) irregular pulses produced by glottal tension. The results showed that irregular pulses were noticed in some but not all [a]s of words which began with the apostrophe. No other significant acoustic differences were noted among conditions. The results suggested that glottal stop in Shugni be described as non‐phonemic vowel laryngealization or creaky phonation. The word‐initial apostrophe had to be treated cautiously to interpret the variation.

Is Russia Becoming a Normal Society?

The word normal is ambiguous in English. It can refer to acting in accord with a given standard of behavior, a norm, or it can refer to the way the average person behaves. In societies in which citizens and institutions act as they ought to, this makes social life both predictable and acceptable. However, what is normalno in Russia is much more problematic. Some scholars have argued that the autocratic institutions of tsarist and Soviet times survived because Russian subjects regarded the state's demands as normal in both the normative and the positive senses.1 However, the Soviet regime has been characterized as a dualistic hourglass society because of a conflict between the norms of the Communist regime and how people actually behaved.2 Vladimir Shlapentokh has recommended managing the resulting tension by adopting the approach of a herpetologist, studying life in A Normal Totalitarian Society as dispassionately as one might study the behavior of other parts of the animal kingdom.3The dissolution of the Soviet Union created the classic structural conditions for anomie in Durkheim's sense of the breakdown of the norms and institutions of polity, economy, and state. The upheavals that followed meant that Russians could not go about their everyday lives normally because they had been socialized to live in the Soviet era. People were forced to cope amidst the turbulence of a society that had not yet established routines of what was normal in the statistical sense. Most Russians have coped by adopting and adapting networks and strategies that were familiar in Soviet times.4By definition, a period of turbulence-and the transformation of Russia's polity, economy, and society was certainly that-can only be sustained for a limited period of time. At some point the void created by the repudiation of the Communist party-state and the command economy is filled by new institutions that require people to behave differently if they are to eat enough, enjoy their leisure, and get the benefits to which they are entitled from public services. Moreover, transformation has brought opportunities that people can seize to better their conditions. For example, by saving money in the knowledge that the shops will have goods if a person can pay the market price or studying English in the expectation that this will lead to a better job.5Two decades after the abrupt start of glasnost and perestroika, Russians have had time to learn, for better or worse, what is now statistically normal in their society. However, the regime's failure to live up to the values that Russians hold about what makes a normal society has led to widespread dissatisfaction with the institutions to which they have had to adapt.6The ambiguity of contemporary Russian life is expressed in the hybrid characterizations that international organizations and many area-studies experts use to describe it. Westerners use compound labels to emphasize values inherent in European norms and deviations from them, such as characterizing the country as partly free or exhibiting managed pluralism or a predatory capitalism. Compound labels can also be used by Russians to emphasize what is valued by the Russian using then. For example, Vladimir Putin's deputy head of administration characterizes the country as a sovereign democracy, an implicit assertion to foreigners that they have no right to comment on what the government does within Russia. The point is made more strongly by Dmitry Medvedev dropping the adjective to assert the claim that Russia is just as democratic as any other country of the G-8, a political challenge to G-7 leaders.However, all assessments of Russian society as a whole have limitations. It is assumed that there is agreement among Russians about what constitutes normal life and that Russians have the same norms and values as Western (that is, European and Anglo-American) citizens. But this assumption has no empirical validity. I draw on New Russian Barometer (NRB) survey data to examine what Russians mean by a normal society, whether they think it is normal today and if not, how many years will it take for Russian society to become normal or if it will ever do so. …

Abrupt and consistent responses of aquatic and terrestrial ecosystems to the 8200 cal. yr cold event: a lacustrine record from Lake Arapisto, Finland

A 8400—7700 yr cal. BP section of the sediments of a small lake in southern Finland was studied by high-resolution pollen and cladoceran analyses to examine the response of terrestrial and aquatic ecosystems to the 8200 cal. yr BP cold event. Furthermore, a pollen-based Tann reconstruction and proportions of chydorid ephippia were used to determine changes in temperature and in the length of open-water season during the event. The pollen data, with abrupt decreases of the early-flowering Alnus, Corylus and Ulmus at c. 8350 cal. yr BP, may partly reflect vegetation dynamics but possibly also decreased pollen productivity and reproduction caused by cold winters and springs. The reconstructed Tann indicated a rapid temperature fall and a subsequent recovery. Proportions of chydorid ephippia suggested a considerable reduction in the length of open-water season at the beginning of the event, followed by periodically shorter open-water seasons. In the aquatic ecosystem only one species, the dominant planktonic cladoceran Bosmina longirostris, responded by decreasing dramatically and almost became extinct during the coldest period. However, we were unable to reconstruct the causative link between the inferred climate change and its decrease. The response of both aquatic and terrestrial proxies at c. 8350 cal. yr BP was consistent, indicating an abrupt start of the event and also an abrupt end at c. 8100 cal. yr BP.

Transient drop deformation upon startup of shear in viscoelastic fluids

Recent experiments show that upon abrupt start of a shear flow, a suspended drop undergoes an overshoot in deformation if either the drop or the matrix is a polymeric fluid. Using a diffuse-interface formulation, we carry out two-dimensional numerical simulations that trace the origin of the transient to the mismatch of two time scales: a capillary time for drop deformation and a relaxation time for the polymers in the viscoelastic component. The results are in qualitative agreement with experiments.

Systemic pneumococcal disease after staging splenectomy for Hodgkin's disease 1969-1980 without pneumococcal vaccine protection: a follow-up study 1994.

We surveyed, during 1994, all 325 patients who underwent staging laparotomy with splenectomy for Hodgkin's disease in Norway 1969-80, before pneumococcal vaccine was available in this country. The patients were thus not immunized preoperatively. Of 162 patients (49.8%) who died before 1994, 8 (2.4% of the total study) died from pneumococcal septicaemia and 16 (6.2%) from infections totally. Of 163 patients (50.2%) who were alive in 1994, 158 cooperated and filled in a questionnaire: 22 had been hospitalized for serious infections; 2 with pneumococcal septicaemia, and 6 with pneumonia, although lacking a specified microbiological diagnosis. We observed 325 patients representing 4420 patient-years, 3066 patient-years among survivors and 1354 patient-years among the dead. This resulted in an incidence rate of systemic pneumococcal disease of 226 per 100,000 patient-years, which is a relative risk of 20.5 compared to the general Norwegian population during 1994. Septicaemia for these patients most often had an abrupt clinical start even for relapse-free individuals and occurred from 2 to 17 yr after splenectomy (mean 10 yr). The risk of developing an overwhelming pneumococcal septicaemia with high case-fatality in asplenic patients seems to persist for these patients at about the same level even 15-20 yr after splenectomy. Only 12.7% of the survivors had been given pneumococcal vaccine in the autumn of 1993. Despite the fact that medical journals and media in Norway focused upon the problem of pneumococcal disease in asplenic individuals in the autumn of 1993 and spring of 1994, a substantial proportion of these patients (55.3%) still remained unimmunized when interviewed in the autumn of 1994. None of our systemic pneumococcal disease patients was vaccinated. Our data underline the need for prophylactic immunization with effective vaccines against pneumococcal infection in splenectomized Hodgkin's disease patients.

Moderate vitamin D 3 supplementation lowers serum 1,25-dihydroxy-vitamin D 3 in rats

We examined how previous vitamin D 3 intake affects serum 1,25-dihydroxyvitamin D 3 (1,25(OH) 2D 3) after the abrupt start of moderate (10 nmol/day) vitamin D 3 doses. Diet calcium and phosphate were normal, but vitamin D 3 content differed among groups. In the rats mildly deprived of dietary vitamin D, serum 1,25(OH) 2D 3 was normal initially, but after the first vitamin D 3 dose, serum 1,25(OH) 2D 3 increased 3-fold, and returned to normal by the second day. In the rats that had been fed normal (2 nmol/day) or elevated (20 nmol/day) vitamin D 3, the vitamin D 3 doses did not produce the transient rise in 1,25-(OH) 2D 3. Before the experiment, rats fed diet with 20 nmol vitamin D 3/day had lower 1,25(OH) 2D 3 than the other groups (p < 0.05). All groups given vitamin D 3 doses for 7 days had lower serum 1,25(OH) 2D 3 by the end of the week (p < 0.05 each). At the end of the study, serum 1,25-(OH) 2D 3 correlated inversely with serum 25-(OH)D 3 (r = −0.608, p < 0.01, n = 28). There were no differences in weight gain, serum calcium or phosphate among the groups. In conclusion, vitamin D 3 doses caused a dramatic, acute rise in serum 1,25(OH) 2D 3 only in rats fed less than the recommended dietary vitamin D. In contrast, a long-term increase in vitamin D 3 intake resulted in lower serum 1,25(OH) 2D 3, and this was evident in every aspect of this study.

Myocardial and microvascular injury following coronary surgery and its attenuation by mode of reperfusion

In 14 patients undergoing coronary surgery, repeated atrial biopsies were obtained before and at the end of ischemia, and at 20 and 60 min of reperfusion. In half of the patients reperfusion was initiated with an abrupt rise in blood temperature and pressure, in the other half with a gradual rise. The biopsies were prepared for transmission electron microscopy and analyzed by stereological technique. In all biopsies, myocytic injury, as revealed by mitochondrial changes and intracellular edema, occurred following ischemia (P = 0.0003 and 0.007, respectively). The intracellular edema regressed following 20 min of reperfusion (P = 0.008). The myocytic mitochondrial changes persisted during reperfusion towards the end of the observation period (P = 0.0001). Interstitial edema increased following ischemia (P = 0.007) and persisted following 60 min of reperfusion (P = 0.009). The capillary part was significantly reduced after 20 min of reperfusion (P = 0.003), probably reflecting interstitial edema. Most changes were reversible in nature, although foci of irreversible changes were shown. In patients with a gradual start of reperfusion there was a significant regression of interstitial edema (P = 0.005) at 60 min reperfusion compared to the patients with an abrupt start, where the same changes seemed to persist or even increase. The study demonstrates that "reperfusion injury" occurs in human myocardium. It can be discerned from "ischemic" injury, and it may be reduced by a gentle mode of reperfusion.

An intervention analysis of the war on poverty: Poverty's persistence and political-business cycle implications

Intervention analysis is used to examine the impact of the War on Poverty on the proportion of income received by families in the lowest quintile of the income distribution in the United States. Evidence presented indicates that the War on Poverty intervention was of the ‘abrupt start, temporary duration’ type and, thus, that the position of the poor was only temporarily affected by the Economic Opportunity Act of 1964 and subsequent programs. Residual analysis suggest an interesting ancillary political economy hypothesis: government programs which are ‘marginally funded’ are more likely to be subject to political fine-tuning before Presidential elections than those that are ‘well advertised’ and ‘fully funded’.

Labour Relations in the Dutch Margarine Industry 1870–1954

A number of new industries were born at the end of the last century, in a manner resembling Aphrodite's rising from the sea. These industries are characterized by an abrupt start, in contrast with other industries that evolved from a traditional craft to a modern industry along an elaborate route of inventions and innovations. Each of these new industries began after one invention, that was so important for the industry concerned that it changed everything. Only the similarity between the final product and the original was maintained. Artificial silk resembled silk, artificial butter resembled normal butter and traditional soap resembled modern soap; yet the industries that produced rayon, margarine and modern soap in no way resembled the crafts that had brought forth the traditional products. Raw materials were used in an unprecedented way and machinery had to be developed. The new industries also brought forth a new type of workers. With no traditional bonds to fall back on, these workers proved difficult to organize. This will be illustrated by the labour relations in one of the most important new Dutch industries: the margarine industry. The margarine industry is not a labour intensive industry. Wages never constituted more than 5%/0 of the total costs. Even at its height, just after the first World War, the industry employed fewer than 8,000 people in the

Modification by chemical stimuli of temporal difference in the onset of inspiratory activity between vagal (superior laryngeal) or hypoglossal and phrenic nerves of the rat.

Temporal differences in the onset of inspiratory activities between the efferent vagal (superior laryngeal, Xsl) or hypoglossal (XII) and phrenic (Phr) nerves were measured at various levels of chemical stimuli in the halothane-anesthetized, vagotomized, and artificially ventilated rat. The onset of Xsl (XII) inspiratory activities always preceded the abrupt start of the Phr discharge. Hyperoxic hypocapnia due to hyperventilation delayed the start of inspiratory activity (reduction in respiratory frequency) and shortened the difference in onset time between the cranial (Xsl, XII) and Phr nerve discharges (Td). During respiratory stimulation due to asphyxia (progressive hypoxia and hypercapnia), the start of Xsl (XII) inspiratory activity became progressively earlier than that of Phr discharge, which extremely prolonged the Td. Severe asphyxia, however, retarded the start of inspiratory activities with accompanying long Td and slow respiratory frequency. The early but gradually augmenting inspiratory activity of the Xsl (XII) nerve was always followed by large bursts synchronized with Phr discharges during altered chemical stimuli. The termination of inspiratory activity, which occurred simultaneously in the three respiratory nerves, was not significantly affected by changes in chemical stimuli except for extreme hypocapnia. The results indicate that changes in chemical stimuli not only alter the start of inspiratory activity but also influence the transition from the initial slow onset to the final synchronized inspiratory activity in the Xsl (XII) nerve. The apparent dissociation of the onset time between the Xsl (XII) and Phr nerve discharges shows that the temporal aspect of the brain stem process(es) for starting inspiratory activities may not be determined from the trajectory of Phr discharges only.

Adaptation of sorghum/maize and sorghum/pearl millet intercrop systems to the toposequence land types in the North Sudanian zone of the west African Savanna

Cereal/cereal intercrop systems are commonly used by farmers in the higher-rainfall areas of the South Sudanian and Guinean savanna zones of West Africa. Towards the North Sudanian zone these systems become less common, because of a shorter rainy season with a more abrupt start and end. However, previous work on the responses of maize ( Zea mays), sorghum ( Sorghum bicolor), and pearl millet ( Pennisetum americanum) crops to the different toposequence land types indicated that crop mixtures of sorghum/millet for uplands and sorghum/maize for lowlands would be less prone to drought stress and waterlogging risks than would the respective sole crops. The present studies showed consistent intercropping advantages of at least 25% for sorghum/maize systems when both crops are sown at the same time. The relative advantages from this system were greatest for the uplands. Intercropping advantages were generally less for the sorghum/millet systems, and it proved essential to delay the millet sowing to prevent serious competition to the sorghum. Sorghum/millet intercropping provides a risk-reducing alternative to sole cropping, because sorghum plants lost during the common early droughts can be replaced by an early-maturing millet sown in July. However, because of the unpredictability of the early-season rainfall, sorghum/millet systems will be difficult to standardize; both the sowing date and the plant densities of the component crops may require adjustments each year in response to the starting date of the rains and the extent to which the sorghum has survived the early-season droughts.

Generation of initial wavelets by instability of a coupled shear flow and their evolution to wind waves

The generation of initial wavelets, which appear at the initial stage of the generation and growth processes of wind waves after the abrupt start of the wind on a still water surface, has been investigated by systematic experiments together with theoretical analyses. The energy of the initial wavelets, measured by a resistance-type wave gauge of 50 μm diameter, grew exponentially with time at a constant frequency. The frequency and the growth rate were independent of the fetch but did depend on the friction velocity u*a of the air. The phase velocity of the initial wavelets, measured by a shadowgraph-photography technique, was nearly constant, independent of u*a. A coupled shear flow model in the air and water was examined, to explain the observed characteristics of the initial wavelets in terms of the instability mechanism. The theoretical analysis showed that, for each shear flow pattern observed in the experiments, there exist waves whose growth rate is maximum. The frequency, the growth rate and the phase velocity of these critical waves were virtually coincident with those properties of the observed initial wavelets. It is concluded that the generation of wind waves, whose initial stage is called the initial wavelets, is caused by the selective amplification, by the instability mechanism, of the small perturbations which inevitably occur in the flow.The limitation of the linear instability theory as applied to the process of further growth of the wind waves is also discussed. From some facts recognized through detailed observations, it is inferred that the phenomena controlled by the linear mechanism last for only about 10 s, and that these evolve to the wind waves which are characterized by inherent nonlinearity.

Rotating elliptic cylinders in a viscous fluid at rest or in a parallel stream

Numerical solutions are presented for laminar incompressible fluid flow past a rotating thin elliptic cylinder either in a medium at rest at infinity or in a parallel stream. The transient period from the abrupt start of the body to some later time (at which the flow may be steady or periodic) is studied by means of streamlines and equi-vorticity lines and by means of drag, lift and moment coefficients. For purely rotating cylinders oscillatory behaviour from a certain Reynolds number on is observed and explained. Rotating bodies in a parallel stream are studied for two cases: (i) when the vortex developing at the retreating edge of the thin ellipse is in front of the edge and (ii) when it is behind the edge.

Affiliation between the sexes in common grackles i. specificity and seasonal progression.

Heterosexual affiliation involves behavioral mechanisms that limit bond membership and regulate partners interactions. Among Common Grackles, Quiscalus quiscula, two characteristic activities of partners, following and vocal answering, develop during group activities and promote the individual specificity of pair bonds. Pairs differ substantially in the durations and seasonal timing of the early stages of nesting activities and in the male's fidelity to his mate through incubation. After the relatively abrupt start of intensive nest-building, the seasonal course of a pair's behavior becomes more regular, an indication that this transition in the female's state is critical in pacing the pair's breeding activities. Aggression serves primarily to adjust the spatial relationships of individuals, both between partners and between unpaired birds. males that deserted their mates during incubation had earlier performed precopulatory displays to other males.

K-Ar ages from the Near Islands, western Aleutian Islands, Alaska: Indication of a mid-Oligocene thermal event

Deformed and metamorphosed basaltic volcanic rocks (one pillow lava, one amphibolite) from the basement on Attu Island have yielded whole-rock K-Ar ages of about 30 m.y. The greenschist (or higher grade) assemblage of these rocks and their presumed correlation with late Eocene or older early-series rocks elsewhere in the Aleutian arc suggest that these dates indicate a time of metamorphism. Similar ages (≅30 m.y.) for two mafic intrusions into the basement may also signify a time of metamorphism. These four ages place an older limit on, and may coincide with, the mid-Tertiary tectonism that deformed rocks of the early series along the length of the Aleutian arc. One post-early-series intrusion on Agattu is 14 m.y. old, in agreement with previous results from Shemya on a similar rock and in accord with the observation of a relatively abrupt start of late Tertiary magmatism throughout the arc about 15 m.y. ago. The youngest recognized igneous activity in the Near Islands is represented by hornblende-bearing rocks (one andesite lava, one dacite dike) on Attu that have yielded ages of 6 to 8 m.y.