On guarantee optimization in control problem with finite set of disturbances

In this paper, we deal with a control problem under conditions of disturbances, which is stated as a problem of optimization of the guaranteed result. Compared to the classical formulation of such problems, we assume that the set of admissible disturbances is finite and consists of piecewise continuous functions. In connection with this additional functional constraint on the disturbance, we introduce an appropriate class of non-anticipative control strategies and consider the corresponding value of the optimal guaranteed result. Under a technical assumption concerning a property of distinguishability of the admissible disturbances, we prove that this result can be achieved by using control strategies with full memory. As a consequence, we establish unimprovability of the class of full-memory strategies. A key element of the proof is a procedure of recovering the disturbance acting in the system, which allows us to associate every non-anticipative strategy with a full-memory strategy providing a close guaranteed result. The paper concludes with an illustrative example.

Chronotype as self-regulation: morning preference is associated with better working memory strategy independent of sleep

Study objectives We set out to examine how chronotype (diurnal preference) is connected to ability to function in natural conditions where individuals cannot choose their sleep schedule. We conducted a cross-sectional study in military conscript service to test the hypothesis that sleep deprivation mediates the adverse effects of chronotype on cognitive functioning. We also examined the effects of time of day. Methods 140 participants (ages 18-24 years) completed an online survey, including the Morningness-Eveningness Questionnaire (MEQ) and a Cambridge Neuropsychological Test Automated Battery (CANTAB). Most (n=106) underwent an actigraphy recording. After bivariate analyses, we created a mediation model (self-reported sleepiness and sleep deprivation mediating effect of chronotype on cognition) and a moderation model (synchrony between most alert time and testing time). Results Reaction times in inhibition task correlated negatively with sleep efficiency and positively with sleep latency in actigraphy. There was no relation to ability to inhibit responses. More significantly, spatial working memory performance (especially strategicness of performance) correlated positively with morning preference and negatively with sleep deprivation before service. Synchrony with most alert time of the day did not moderate these connections. No other cognitive task correlated with morningness or sleep variables. Conclusions In line with previous research, inhibitory control is maintained after insufficient sleep but with a tradeoff of slower performance. The connection between morning preference and working memory strategy is a novel finding. We suggest that diurnal preference could be seen as an adaptive strategy, as morningness has consistently been associated with better academic and health outcomes.

A Symbiotic Organisms Search Algorithm With Memory Guidance for Global Optimization Problems

Symbiotic organisms search (SOS) algorithm is a nature-inspired meta-heuristic algorithm, which has been successfully applied to solve a large number of problems of different areas. In this work, a novel modified variant of SOS with a memory strategy and good-point set (GMSOS) is proposed to improve the properties of exploration and exploitation. For improving the population diversity and the search capability of the SOS algorithm, the good point set theory rather than random selection is used to generate the initial population, and the memory strategy is adopted in three phases of the SOS algorithm, which aims at maintaining the trade-off between exploration and exploitation effectively, and preventing the current best solution from getting trapped into local optima. The performance of the proposed version of SOS is tested on standard benchmark functions with different characteristics and real-world problems. The numerical and statistical results on these applications demonstrate the competitive ability of the proposed algorithm as compared to other popular algorithms available in the literature.

Strategi Peningkatan Keterampilan Bahasa Inggris Pelaku Wisata Di Desa Wisata Tista, Kerambitan, Tabanan

English communication is a problem faced by the human resources involved in the tourism activities in Desa Wisata Tista, Kerambitan Subdistrict, Tabanan Regency, Bali. However, there had been no research that identified English problems. Then, this research was done to (1) identify the problem faced by the human resources involved in tourism activities in Desa Wisata Tista, Kerambitan Subdistrict, Tabanan Regency, Bali and (2) finding out the proper and suitable English learning strategies to improve the English mastery of the human resources involved in the tourism activities in Desa Wisata Tista, Kerambitan Subdistrict, Tabanan Regency, Bali. The data used in this research were gained through interviews, observation, and literature studies. The data were analyzed qualitatively. The results of the analysis reveal that (1) the numbers of the human resources who can speak English is limited, (2) the lack of speaking skills using English, (3) the lack of English vocabulary they have, and (4) low level of self-confidence to communicate in English. These problems can be overcome by implementing several strategies, namely (1) memory strategy, (2) cognitive strategy, (3) affective strategy and (4) social strategy. Based on the identification, the managers can conduct English course for the community. Keywords: English Communication, English Learning Strategies, English Communication Problems, English for Tourism Workers

Strategy Use Mediates the Relation between Openness to Experience and Episodic Memory in Younger and Older Adults

Previous research has shown that people with higher levels of Openness to Experience show higher levels of cognitive functioning. However, the mechanisms underlying this personality-cognition relation are not well understood. The goal of the current project was to examine whether strategy use mediates the relation between Openness to experience and retrospective memory, and whether the role of strategy use in the Openness-memory relation was the same in younger and older adults. Method: Two studies were conducted. In each of them, younger and older adults were administered a retrospective memory task (29 younger and 27 older in Study 1, 43 adults of all ages in Study 2). They were asked to report the strategies they used during the task, and to complete an Openness to Experience scale. Results: Consistent with previous reports, higher scores of Openness to experience and greater use of efficient memory strategies were associated with higher levels of memory performance. In addition, individual differences in memory strategy use mostly mediated the relation between Openness and memory performance. Results did not support a mediation model moderated by age. That is, the role of memory strategy use in the relation between Openness and memory was the same in younger and older adults. Conclusion: Higher levels of Openness are associated with better memory performance, mostly because people with higher levels of Openness use more efficient memory strategies.