Absence Of Leader Research Articles

Learning‐based containment control in the absence of leaders' information

AbstractThis article considers the containment control problem of continuous‐time dynamic agents without leaders' state information. The leaders have first‐ and second‐order dynamics, respectively, while first‐order dynamics always govern the followers. Each agent has inherent nonlinear dynamics and can only measure the output information of its neighbors. The output of each leader is expressed as the product of an unknown coefficient and a position‐like state, while the output of each follower is equal to its position‐like state. To stabilize the position‐like states of the followers to the convex hull spanned by leaders, the unknown coefficients are asymptotically tracked by leveraging reinforcement learning based on the inherent dynamics and the output information. Two distributed learning‐based containment protocols are proposed, respectively. It is proved that if the directed communication topology has a spanning forest and certain conditions in terms of the inherent nonlinear dynamics are satisfied, then the proposed controllers with proper control gains solve the containment control problem asymptotically under arbitrary initial states. An exciting conclusion is that the learning algorithms' convergence rate plays an important role in achieving containment control. Numerical simulations are performed to validate the effectiveness of the obtained theoretical results.

Decentralized composting: gated communities as ecologically promising environments.

The global need to strengthen circular economic chains highlights the importance of composting, since the organic fraction corresponds, on average, to 50% of the municipal solid waste. As centralized composting programs have been showing slow advances, especially in low and middle-income countries, the decentralized scale is a promising tool. Gated communities stand out as potential targets for decentralized composting programs, as they generally have organization, tools, employees, space, and a high density of gardens. This study detected, through online questionnaires sent to residents of gated communities, a high probability of adherence to composting programs in the condominium, predisposition for waste sorting, use of the compost, and participation in meetings to address the issue, in addition to a relevant potential for reducing the disposal of organic waste in landfills. On the other hand, the absence of leaders, lack of knowledge about community projects and fear of unpleasant odors and pests were evidenced. Among 106 respondents, residents of 25 condominiums, no variability was detected between positions of different genders, ages, and education. This diagnosis points out challenges and suggests alternatives to overcome them, based on successful experiences, focused on strengthening leadership, technical training, provision of equipment, improvements in communication and socio-environmental awareness.

Determinates of Customer Services Delivery in Civil Service Office: In Case of Sheka Zone Civil Service Office

Providing quality service to customer is very important for the success of any service delivered organization. Therefore they are very important for the customers too. This study aimed to examine the determinants of customer service delivery of civil service office in sheka zone civil service office. The study was conducted from June 2020 to august 2020. A questionnaire was designed to collect the data on the determinant factors like office bureaucracy, procrastination, absence of leader or manager in office, sociability of leader, time limitation that given for each server, time scheduled program manager or leader contact with customer, transparency and customer service delivery. The study was used explanatory research design and both primary and secondary data was used to conduct this study. Simple random sampling technique was used to select the office and the data was collected through convince method to infer the target population of the study. The data was collected from the customers of sheka zone civil service office. The collected data was analyzed by SPSS 20 Version. Descriptive and explanatory statistics was used to analyze the data and a sample of 385 customers was used to collect the data. Besides, descriptive statistical tools like maximum, minimum, mean and standard deviation. The study revealed that majority of the respondents feel agreed on determinant factors influence the service delivery. Inferential statistical methods like correlation analysis was used to assess the relationship between determinant factors and customer service delivery, multiple linear regression analysis also was employed to examine the influence of determinant factors on customer service delivery by using primary data collected through five scale likert questionnaire. Based on the findings of the study, from determinant factors of customer service delivery office bureaucracy, procrastination and absence of leader or manager in office have a negative and sociability of leader, time limitation that given for each server, time scheduled program manager or leader contact with customer and transparency have a positive and statistically significant correlation with customer service delivery. The multiple linear regression analysis (R2) implies that about 88.1% shows that the determinant factors determine the variation of customer service delivery of sheka zone civil service office. Also the regression result revealed that all explanatory variables have a statistically significant effect on customer service delivery. This indicated that determinant factors determine customer service delivery of sheka zone civil service office. Therefore, sheka zone civil service office should give primacy to avoid those bottlenecks appropriately to provide continuously as an indispensable tool to improve and maintain sustainable customer service delivery. Keywords : customer service delivery, office bureaucracy, procrastination, absence of leader or manager in office, sociability of leader, time limitation that given for each server, time scheduled program manager or leader contact with customer and transparency DOI: 10.7176/EJBM/13-7-01 Publication date: April 30 th 2021

Observer-based adaptive fixed-time formation control for multi-agent systems with unknown uncertainties

This paper investigates the fixed-time formation tracking control problem for multi-agent systems with model uncertainties and in absence of leader’s velocity measurements. For each follower, a novel fixed-time cascaded leader state observer (FTCLSO) without velocity measurements is first designed to reconstruct the states of the leader. Then, radial basis function neural networks (RBFNNs) are adopted to approximate the model uncertainties online. Based on the proposed FTCLSO and RBFNNs, a novel fixed-time formation control scheme is constructed to address the time-varying formation tracking problem by utilizing fixed-time nonsmooth backstepping technique. The fixed-time convergence of the formation tracking error is guaranteed through Lyapunov stability analysis. Finally, simulation results demonstrate the effectiveness of the proposed formation tracking control scheme.

Fixed‐time observer based adaptive neural network time‐varying formation tracking control for multi‐agent systems via minimal learning parameter approach

This study proposes a novel control scheme to investigate the time-varying formation tracking control problem for multi-agent systems with model uncertainties and the absence of leader's velocity measurements. For each agent, a novel fixed-time cascaded leader state observer (CLSO) without velocity measurements is first designed to reconstruct the states of the leader. Radial basis function neural networks (RBFNNs) are adopted to deal with the model uncertainties online. Taking the square of the norm of the NN weight vector as a newly developed adaptive parameter, a novel RBFNN-based adaptive control scheme with minimal learning-parameter approach and fixed-time CLSO is then constructed to tackle the time-varying formation tracking problem. The uniform ultimate boundedness property of the formation tracking error is guaranteed through Lyapunov stability analysis. Finally, two simulation scenario results demonstrate the effectiveness of the proposed formation tracking control scheme.

YOUTH POLICY IN MODERN RUSSIA. ABSENTEEISM AND POLITICAL PROTEST

The article analyzes the features of the current youth policy of the Russian Federation aimed at raising the political culture. Despite the current activities of the government institutions in the field under study, absenteeism, as well as the protest potential of the young people, remains at a fairly high level. In this regard, the government acknowledged the importance of forming a positive image of the state power in the eyes of young people and strengthen its influence in the sphere of forming loyal associations, which is not always positively perceived among the youth. The work focuses on the fact that raising the loyalty of youth organizations is one of the factors of political stability, both in case of internal turbulence and external influence. The authors also focus on the beneficiaries of youth protests. The authors paid special attention to the issue of forming political leadership among the youth and the absence of leaders expressing the opinions of young people in modern Russian politics. At the same time, youth protest as a social phenomenon lack class and in some cases ideological differences. The authors come to the conclusion that despite the steps taken by the government and political parties to involve Russian youth in the political agenda, the young people reject leaders of youth opinion imposed by the authorities, either cultivating nonparticipation in the electoral campagines or demonstrating latent protest voting.

Visual cryptographic schemes using combined Boolean operations

Visual Cryptographic scheme (VCS) is a variant form of secret sharing method to encode a secret image into n distinct shares. The dealer distributes shares to each participants in such a way that, while certain qualified subsets of participants can visually recover the secret, but other forbidden sets of participants have no information on the secret. Such a system is the general access structures in VCS. The essential access structure (k, n)* is a type of threshold scheme were one participant is the leader who holds the essential share and the remaining n-1 shares are given to n-1 participants. The secret image cannot be retrieved in the absence of leader and the leader needs the support of at least k-1 remaining participants to recover the secret image. Small pixel expansion and maximum contrast are the basic parameters for measuring the quality of the VCS. In the literature there are constructions for both deterministic and probabilistic (k, n)*-VCS. The following are the important contributions of this paper. (1) A deterministic (k, n)*-VCS with improved contrast. (2) A deterministic (k, n)- VCS for t essential participants with improved contrast and less pixel expansion. (3) An ideal contrast general access structure construction with AND operation for grey scale images. (4) An ideal contrast (k, n)*-VCS construction for both binary and grey scale images. (5) An ideal contrast (k, n)-VCS for t essential participants for both binary and grey scale images.

Servant leadership and conflict resolution: a qualitative study

Purpose The purpose of the present study was to examine the choice of conflict management strategies made by servant leaders. Design/methodology/approach The present qualitative study uses the method of narrative enquiry within the framework of interpretative phenomenological analysis (Smith et al., 2009) to capture the life experiences as lived. Findings The study suggests that the servant leaders manifest conflict management styles which are more persuasive, humane and participative. Their chief strategies for resolving subordinate-subordinate conflict are initial diagnosis of the situation; leader’s intervention in facilitating an amicable solution; and impartiality of the leader while effecting resolution of conflict. Diagnosis of the conflict situation, self-restraint, patience, composure and humility of the servant leader have emerged as major leadership characteristics, as well as strategies for dealing with any provocative employee behavior. Practical implications Insight provided by this study into alternate strategies for conflict resolution will guide the academicians, working managers and trainers to understand and practice the process of managing conflict in a more humane way. Originality/value Despite the presence of a few studies linking leadership style with the choice of conflict resolution strategies, an important gap till now has been the absence of leaders’ personal account of their experiences, reflections and analysis in their choice of conflict resolution strategies. This study seeks to investigate the approach of servant leaders when they handle subordinate-subordinate and superior-subordinate conflict.

The synchronization of instantaneously coupled harmonic oscillators using sampled data with measurement noise

In this brief, we propose an effective algorithm for synchronization of instantaneously coupled harmonic oscillators by using sampled data which may contain measurement noise. We discuss the convergence of this algorithm for both fixed and switching directed network topologies in the presence or absence of leaders. We also establish sufficient conditions under which the coupled harmonic oscillators could attain synchronized oscillatory motions in the presence of noise. And moreover, it is shown that synchronization can be attained even when the velocity information is exchanged only at discrete-time instants. Finally, we give some numerical examples to illustrate the effectiveness of the theoretical results.

Self-organization in the dynamics of huddling behavior in Octodon degus in two contrasting seasons

In small mammals, huddling appears as an efficient response to low temperature with important consequences in energy saving, which in turn affect individual fitness. It has been proposed that this behavior is a self-organized process. However, to prove self-organization, it is necessary to study the dynamics of huddling, ruling out the presence of leaders. The objectives of this study were to determine the dynamics of huddling at different temperatures in Octodon degus, documenting the presence or absence of leaders, and to study the consistency of this behavior in two contrasting seasons. We found that huddling dynamics did not indicate the presence of leader initiators of the clustering at lower temperatures. There was no deterministic pattern in huddling dynamics, in any period or at any temperature, suggesting a behavior triggered spontaneously without any order, hierarchy, or recipes. The effect of temperature on huddling behavior was marked and similar in both seasons. The variability of the huddled groups was greater at higher temperatures, which is explained by a greater movement of individuals and more frequent variations in the number and size of the groups at higher temperatures. The results describe huddling as a self-organized behavior, more economical than other physiological processes and therefore preserved by natural selection. This increases its importance for survival and fitness given the significant reduction in energy expenditure achieved under conditions of low temperatures and reduced availability of food, such as during the breeding season of O. degus.

Landing together: How flocks arrive at a coherent action in time and space in the presence of perturbations

Collective motion is abundant in nature, producing a vast amount of phenomena which have been studied in recent years, including the landing of flocks of birds. We investigate the collective decision making scenario where a flock of birds decides the optimal time of landing in the absence of a global leader. We introduce a simple phenomenological model in the spirit of the statistical mechanics-based self-propelled particles (SPPs) approach to interpret this process. We expect that our model is applicable to a larger class of spatiotemporal decision making situations than just the landing of flocks (which process is used as a paradigmatic case). In the model birds are only influenced by observable variables, like position and velocity. Heterogeneity is introduced in the flock in terms of a depletion time after which a bird feels increasing bias to move towards the ground. Our model demonstrates a possible mechanism by which animals in a large group can arrive at an egalitarian decision about the time of switching from one activity to another in the absence of a leader. In particular, we show the existence of a paradoxical effect where noise enhances the coherence of the landing process.

Adaptive formation control in absence of leader's velocity information

In the leader-following approach, it has been commonly assumed that the leader robot's velocity information may be either measured or telecommunicated. However, in some circumstances, it is difficult to satisfy it because the follower robots may not have the sensor or the communication device to obtain accurate enough leader robot's velocity. Therefore this study proposes an adaptive formation control approach for multiple mobile robots in the absence of the velocity information of the leader robot. The proposed control system only requires a knowledge of the leader–follower relative distance and the bearing angle. The smooth projection algorithm is employed to estimate time-invariant or time-varying velocities of the leader robot. Using Lyapunov stability theory, it is shown that the formation errors are uniformly ultimately bounded and converge to an adjustable neighbourhood of the origin. Simulation and experiment results are provided to demonstrate the performance and stability of the proposed formation scheme.

The 5′-untranslated region of the maize alcohol dehydrogenase gene provides efficient translation of mRNA in plants under stress conditions

Reduced level of expression of most cell proteins under stress conditions is determined by low efficiency of cap-dependent translation of corresponding mRNAs. The maize gene encoding alcohol dehydrogenase, adh1, is an example of a gene which mRNA is efficiently translated under hypoxia. Using reporter gene assay we showed that the leader sequence of adh1 mRNA, provides efficient translation of reporter gene gfp in Nicotiana benthamiana cells under hypoxia and heat shock. The presence of this leader sequence in 5' UTR of mRNA does not change the level of expression in aerobic conditions, but under hypoxia and heat shock the levels of reporter gfp expression were reduced about 5-10 fold in the absence of leader and remained unaffected in its presence in 5'UTR. We found that this leader sequence does not change the level of mRNA stability and does not exhibit promoter activity. Consequently, leader sequence acts as translational enhancer providing efficient translation of mRNA in plant cells under stress conditions. Introduction of this sequence into standard expression cassettes may be used for development of new systems of expression of target proteins in plants, efficient under stress conditions.

Social capital, local networks and community action: Experiences with services upgrading in Kumasi, Ghana

Ghana's transition to democratic and decentralised governance has profoundly altered the context for community action in urban services upgrading. In this article, variations in the way communities have managed to grasp new opportunities are discussed and related to the concept of social capital. Attention is given to the roles of local leaders, levels of internal social cohesion, and the nature of interactions between leaders and followers, and between leaders and the local state. Several threats to effective community action are identified, including: arbitrary and clientelistic politics; restricted opportunities for ordinary citizens to voice their needs; distrust towards the local authorities; and the absence of leaders who can make a difference. The continued importance of the chieftaincy institution in community action, due to its control over land and the reverence and recognition accorded it in local culture, is underscored. Finally, some critical remarks are made regarding the impact of formal in...

An AUG initiation codon, not codon-anticodon complementarity, is required for the translation of unleadered mRNA in Escherichia coli.

We determined the in vivo translational efficiency of 'unleadered' lacZ compared with a conventionally leadered lacZ with and without a Shine-Dalgarno (SD) sequence in Escherichia coli and found that changing the SD sequence of leadered lacZ from the consensus 5'-AGGA-3' to 5'-UUUU-3' results in a 15-fold reduction in translational efficiency; however, removing the leader altogether results in only a twofold reduction. An increase in translation coincident with the removal of the leader lacking a SD sequence suggests the existence of stronger or novel translational signals within the coding sequence in the absence of the leader. We examined, therefore, a change in the translational signals provided by altering the AUG initiation codon to other naturally occurring initiation codons (GUG, UUG, CUG) in the presence and absence of a leader and find that mRNAs lacking leader sequences are dependent upon an AUG initiation codon, whereas leadered mRNAs are not. This suggests that mRNAs lacking leader sequences are either more dependent on perfect codon-anticodon complementarity or require an AUG initiation codon in a sequence-specific manner to form productive initiation complexes. A mutant initiator tRNA with compensating anticodon mutations restored expression of leadered, but not unleadered, mRNAs with UAG start codons, indicating that codon-anticodon complementarity was insufficient for the translation of mRNA lacking leader sequences. These data suggest that a cognate AUG initiation codon specifically serves as a stronger and different translational signal in the absence of an untranslated leader.

Newtonian Dynamical Approach to Fish Schooling

Schools are groups of fish engaging in cohesive movements with parallel orientation. Schooling fish perform a well-organized collective motion by some kind of social interaction even in the absence of leaders or external stimuli. In this paper, a Newtonian model is developed for schooling behavior to study the self-organizing (i.e., decentralized control) mechanism of a school in a setting of collective motion of autonomous individuals, that is, within a Langrangian (i.e., individual-based) framework of N-fish motion dynamics. The school is modeled as an interacting particle system with behavioral and environmental stochasticity, such as gas molecules following the rules of Newton's mechanics. Two equations for the school mean and the variance of swimming velocity are derived from the Langrangian model which has a great degree of freedom ( N>> 1). These two reduced equations of motion of the system illustrate a feed-forward control structure underlying the self-organization of the school. On the basis of these equations, the transient process in which the system approaches the stationary polarized schooling is investigated. Features of the temporal evolution of the system from the motionless state of the non-polarized aggregation to the onset of the polarized school are extracted by calculating the following: transient fluctuation of the individual velocity in a school, transient fluctuation of the centroid velocity of a school, two-time correlation of initial fluctuation of the centroid velocity, and temporal evolution of the mean square velocity of the center of school, which are regulated by individual stochastic movement in a school and nonlinearity of a system. Experimental observations of the transient behavior of schooling are consistent with the theoretical predictions. It is expected that the transient fluctuation of the centroid velocity shows the enhancement at around the onset-time of schooling structure. The fluctuation enhancement is found to be the essential mechanism for the onset of schooling.